Optimize associative constant patterns to fixed point (#8147)

Re-associating constants can enable further simplification e.g. when
those constant become all zero/all ones. Run these patterns to fixed
point to capture the simplification, by revisiting the node.

.github/actions/artifact-cache/action.yml

@@ -0,0 +1,165 @@
+---
+# DESCRIPTION: Github actions composite action
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+name: Artifact cache
+description: >-
+  Cache a directory across workflow runs using a GitHub Actions artifact instead
+  of actions/cache (useful where artifacts are preferable, e.g. no 10 GB limit
+  on public repos). The base 'key' is scoped automatically: per pull request
+  (<key>-pr-<N>) or per branch (<key>-branch-<name>), and on a PR restore falls
+  back to the target branch's cache. Call once with mode=restore before the work
+  and once with mode=save after, passing the same 'key' and 'path'.
+
+  Branch-scoped restores are provenance-checked (the artifact must come from a
+  same-repo push to that branch) - artifact names are a global, unauthenticated
+  namespace, so otherwise a fork PR could forge one.
+
+  mode=restore calls the GitHub API via 'gh', so the caller's job must grant
+  'actions: read'.
+
+inputs:
+  mode:
+    description: "'restore' or 'save'"
+    required: true
+  path:
+    description: "Directory to cache (archived on save, extracted into on restore)"
+    required: true
+  key:
+    description: "Base artifact name; scoped per PR/branch automatically"
+    required: true
+  retention-days:
+    description: "Artifact retention in days (mode=save)"
+    required: false
+    default: '3'
+  token:
+    description: "Token for the GitHub API (mode=restore); defaults to the job's GITHUB_TOKEN"
+    required: false
+    default: ''
+
+outputs:
+  key:
+    description: "Echoes the input 'key', so a later save can reuse it without repeating the expression"
+    value: ${{ inputs.key }}
+  cache-hit:
+    description: "'true' if an artifact was restored (mode=restore)"
+    value: ${{ steps.restore.outputs.cache-hit }}
+
+runs:
+  using: composite
+  steps:
+    - name: Check mode
+      shell: bash
+      env:
+        MODE: ${{ inputs.mode }}
+      run: |
+        case "$MODE" in
+          restore|save) ;;
+          *) echo "::error::artifact-cache: 'mode' must be 'restore' or 'save' (got '$MODE')"; exit 1 ;;
+        esac
+
+    # Scope the base key: <key>-pr-<N> for pull requests (with the target branch
+    # as fallback), else <key>-branch-<name>. Refs come via env, not ${{ }}
+    # interpolation, so a branch name with shell metacharacters can't inject.
+    - name: Compute artifact name
+      id: name
+      shell: bash
+      env:
+        BASE_KEY: ${{ inputs.key }}
+        EVENT_NAME: ${{ github.event_name }}
+        PR_NUMBER: ${{ github.event.pull_request.number }}
+        BASE_REF: ${{ github.event.pull_request.base.ref }}
+        REF_NAME: ${{ github.ref_name }}
+      run: |
+        set -euo pipefail
+        sanitize() { printf '%s' "$1" | tr '/' '-'; }  # artifact names cannot contain '/'
+        if [ "$EVENT_NAME" = pull_request ]; then
+          {
+            echo "primary=${BASE_KEY}-pr-${PR_NUMBER}"
+            echo "primary-branch="
+            echo "fallback=${BASE_KEY}-branch-$(sanitize "$BASE_REF")"
+            echo "fallback-branch=$BASE_REF"
+          } >> "$GITHUB_OUTPUT"
+        else
+          {
+            echo "primary=${BASE_KEY}-branch-$(sanitize "$REF_NAME")"
+            echo "primary-branch=$REF_NAME"
+            echo "fallback="
+            echo "fallback-branch="
+          } >> "$GITHUB_OUTPUT"
+        fi
+
+    - name: Restore artifact cache
+      id: restore
+      if: ${{ inputs.mode == 'restore' }}
+      continue-on-error: true  # a cold start is fine; a restore failure must not fail the caller
+      shell: bash
+      env:
+        GH_TOKEN: ${{ inputs.token || github.token }}
+        CACHE_PATH: ${{ inputs.path }}
+        PRIMARY: ${{ steps.name.outputs.primary }}
+        PRIMARY_BRANCH: ${{ steps.name.outputs.primary-branch }}
+        FALLBACK: ${{ steps.name.outputs.fallback }}
+        FALLBACK_BRANCH: ${{ steps.name.outputs.fallback-branch }}
+      run: |
+        set -euo pipefail
+        mkdir -p "$CACHE_PATH"
+        # Newest non-expired artifact named $1 (empty if none). With a non-empty
+        # $2 (branch), require provenance: a same-repo run (head_repository_id ==
+        # repository_id) whose head branch is $2, so a fork cannot forge it.
+        newest_run_id() {
+          want="$1" br="$2" gh api \
+            "/repos/$GITHUB_REPOSITORY/actions/artifacts?name=$1&per_page=100" \
+            --jq '.artifacts[]
+                  | select(.expired == false and .name == env.want)
+                  | select(env.br == ""
+                           or (.workflow_run.head_branch == env.br
+                               and .workflow_run.head_repository_id == .workflow_run.repository_id))
+                  | [.created_at, (.workflow_run.id | tostring)] | @tsv' \
+            | sort | tail -n1 | cut -f2
+        }
+        restore() {  # $1=name $2=branch(empty ok); returns 0 on a successful restore
+          local name="$1" br="$2" rid tarball
+          [ -n "$name" ] || return 1
+          rid="$(newest_run_id "$name" "$br")" || return 1
+          [ -n "$rid" ] || return 1
+          echo "Restoring '$CACHE_PATH' from artifact '$name' (run $rid)"
+          gh run download "$rid" -R "$GITHUB_REPOSITORY" --name "$name" --dir "$RUNNER_TEMP/artifact-cache-dl" || return 1
+          # Each artifact holds a single tarball; match by extension so the inner
+          # filename is not part of the contract.
+          tarball="$(find "$RUNNER_TEMP/artifact-cache-dl" -name '*.tar.zst' -print -quit)"
+          [ -n "$tarball" ] || return 1
+          tar -I zstd -x -f "$tarball" -C "$CACHE_PATH"
+        }
+        if restore "$PRIMARY" "$PRIMARY_BRANCH"; then
+          echo "Restored from primary key"
+          echo "cache-hit=true" >> "$GITHUB_OUTPUT"
+        elif restore "$FALLBACK" "$FALLBACK_BRANCH"; then
+          echo "Restored from fallback key"
+          echo "cache-hit=true" >> "$GITHUB_OUTPUT"
+        else
+          echo "No matching artifact found; starting cold"
+          echo "cache-hit=false" >> "$GITHUB_OUTPUT"
+        fi
+
+    - name: Pack artifact cache
+      id: pack
+      if: ${{ inputs.mode == 'save' }}
+      shell: bash
+      env:
+        CACHE_PATH: ${{ inputs.path }}
+      run: |
+        set -euo pipefail
+        packdir="$(mktemp -d)"  # unique dir so concurrent saves cannot collide
+        tar -I 'zstd -T0' -cf "$packdir/cache.tar.zst" -C "$CACHE_PATH" .
+        echo "tarball=$packdir/cache.tar.zst" >> "$GITHUB_OUTPUT"
+
+    - name: Upload artifact cache
+      if: ${{ inputs.mode == 'save' }}
+      uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7
+      with:
+        name: ${{ steps.name.outputs.primary }}
+        path: ${{ steps.pack.outputs.tarball }}
+        retention-days: ${{ inputs.retention-days }}
+        overwrite: true
+        compression-level: 0  # tarball is already zstd-compressed

.github/actions/setup-venv/action.yml

@@ -0,0 +1,56 @@
+---
+# DESCRIPTION: Github actions composite action
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+name: Set up Python venv
+description: >-
+  Restore, create, and optionally save the make-managed Python venv in a GitHub
+  Actions cache. The cache key combines the venv path (venvs are not
+  relocatable), the host OS and version, the Python major.minor version, and
+  the python-dev-requirements.txt hash, so any of those changing invalidates
+  it. Requires the already-configured Verilator tree to be present in 'repo'.
+
+inputs:
+  repo:
+    description: "Verilator checkout holding the Makefile and .venv"
+    required: false
+    default: repo
+  save:
+    description: "Save the cache on a miss (set true only on trusted branches)"
+    required: false
+    default: 'false'
+
+runs:
+  using: composite
+  steps:
+    - name: Compute Python venv cache key
+      id: cachekey
+      shell: bash
+      working-directory: ${{ inputs.repo }}
+      run: |
+        source ci/ci-common.bash
+        host="${DISTRO_ID:-$HOST_OS}${DISTRO_VERSION:+-$DISTRO_VERSION}"
+        pyver="$(python3 -c 'import sys; print("%d.%d" % sys.version_info[:2])')"
+        reqs="$(sha256sum python-dev-requirements.txt | cut -d' ' -f1)"
+        venv="${PWD#/}/.venv"  # absolute venv path (leading '/' trimmed)
+        echo "key=venv-${host}-py${pyver}-${reqs}-${venv//\//-}" >> "$GITHUB_OUTPUT"
+
+    - name: Restore Python venv
+      id: venv
+      uses: actions/cache/restore@55cc8345863c7cc4c66a329aec7e433d2d1c52a9  # v5
+      with:
+        path: ${{ inputs.repo }}/.venv
+        key: ${{ steps.cachekey.outputs.key }}
+
+    - name: Create Python venv
+      if: ${{ steps.venv.outputs.cache-hit != 'true' }}
+      shell: bash
+      working-directory: ${{ inputs.repo }}
+      run: make venv
+
+    - name: Save Python venv
+      if: ${{ inputs.save == 'true' && steps.venv.outputs.cache-hit != 'true' }}
+      uses: actions/cache/save@55cc8345863c7cc4c66a329aec7e433d2d1c52a9  # v5
+      with:
+        path: ${{ inputs.repo }}/.venv
+        key: ${{ steps.venv.outputs.cache-primary-key }}

.github/workflows/build-test.yml

@@ -16,6 +16,7 @@ on:
 
 permissions:
   contents: read
+  actions: read
 
 defaults:
   run:
@@ -29,272 +30,141 @@ concurrency:
 jobs:
 
   build-2604-gcc:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+    name: Build | 26.04 | gcc
     uses: ./.github/workflows/reusable-build.yml
     with:
+      cc: gcc
+      runs-on: ubuntu-26.04
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: linux
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
-      dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: ubuntu-26.04, cc: gcc, asan: 0}
 
   build-2604-clang:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+    name: Build | 26.04 | clang
     uses: ./.github/workflows/reusable-build.yml
     with:
+      cc: clang
+      dev-asan: true  # Build (and run) with address sanitizer
+      runs-on: ubuntu-26.04
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: linux
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
-      dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: ubuntu-26.04, cc: clang, asan: 1}
 
   build-2404-gcc:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+    name: Build | 24.04 | gcc
     uses: ./.github/workflows/reusable-build.yml
     with:
+      cc: gcc
+      runs-on: ubuntu-24.04
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: linux
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
-      dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: ubuntu-24.04, cc: gcc, asan: 0}
 
   build-2404-clang:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+    name: Build | 24.04 | clang
     uses: ./.github/workflows/reusable-build.yml
     with:
+      cc: clang
+      runs-on: ubuntu-24.04
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: linux
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
-      dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: ubuntu-24.04, cc: clang, asan: 0}
 
   build-2204-gcc:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+    name: Build | 22.04 | gcc
     uses: ./.github/workflows/reusable-build.yml
     with:
+      cc: gcc
+      runs-on: ubuntu-22.04
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: linux
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
-      dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: ubuntu-22.04, cc: gcc, asan: 0}
 
-  build-osx-gcc:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+  build-macos-15-clang:
+    name: Build | macos-15 | clang
     uses: ./.github/workflows/reusable-build.yml
     with:
+      cc: clang
+      runs-on: macos-15
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: osx
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
-      dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: macos-15, cc: gcc, asan: 0}
-
-  build-osx-clang:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
-    uses: ./.github/workflows/reusable-build.yml
-    with:
-      sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: osx
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
-      dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: macos-15, cc: clang, asan: 0}
 
   build-windows:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}
-    runs-on: ${{ matrix.os }}
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: windows-2025-vs2026, cc: msvc}
-    env:
-      CI_OS_NAME: win
-      CCACHE_COMPRESS: 1
-      CCACHE_DIR: ${{ github.workspace }}/.ccache
-      CCACHE_LIMIT_MULTIPLE: 0.95
+    name: Build | windows-2025-vs2026 | msvc
+    runs-on: windows-2025-vs2026
     steps:
-      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
         with:
           path: repo
-      - name: Cache $CCACHE_DIR
+      - name: Cache win_flex_bison
         uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9  # v5
         with:
-          path: ${{ env.CCACHE_DIR }}
-          key: msbuild-msvc-cmake
+          path: ${{ github.workspace }}/win_flex_bison
+          key: win_flex_bison
       - name: compile
-        env:
-          WIN_FLEX_BISON: ${{ github.workspace }}/.ccache
         run: ./ci/ci-win-compile.ps1
       - name: test build
         run: ./ci/ci-win-test.ps1
-      - name: Zip up repository
-        run: Compress-Archive -LiteralPath install -DestinationPath verilator.zip
-      - name: Upload zip archive
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7
-        with:
-          path: ${{ github.workspace }}/repo/verilator.zip
-          name: verilator-win.zip
 
   test-2604-gcc:
-    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.reloc && 'reloc | ' || '' }} ${{ matrix.suite }}
+    name: Test | 26.04 | gcc | ${{ matrix.suite }}
     needs: build-2604-gcc
     uses: ./.github/workflows/reusable-test.yml
     with:
       archive: ${{ needs.build-2604-gcc.outputs.archive }}
-      os: ${{ matrix.os }}
-      cc: ${{ matrix.cc }}
-      reloc: ${{ matrix.reloc }}
+      cc: gcc
+      runs-on: ubuntu-26.04
       suite: ${{ matrix.suite }}
-      dev-gcov: 0
     strategy:
       fail-fast: false
       matrix:
-        include:
-          # Ubuntu 26.04 gcc
-          - {os: ubuntu-26.04, cc: gcc, reloc: 0, suite: dist-vlt-0}
-          - {os: ubuntu-26.04, cc: gcc, reloc: 0, suite: dist-vlt-1}
-          - {os: ubuntu-26.04, cc: gcc, reloc: 0, suite: dist-vlt-2}
-          - {os: ubuntu-26.04, cc: gcc, reloc: 0, suite: dist-vlt-3}
-          - {os: ubuntu-26.04, cc: gcc, reloc: 0, suite: vltmt-0}
-          - {os: ubuntu-26.04, cc: gcc, reloc: 0, suite: vltmt-1}
-          - {os: ubuntu-26.04, cc: gcc, reloc: 0, suite: vltmt-2}
+        suite: [dist-vlt-0, dist-vlt-1, dist-vlt-2, dist-vlt-3, vltmt-0, vltmt-1, vltmt-2]
 
   test-2604-clang:
-    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.reloc && 'reloc | ' || '' }} ${{ matrix.suite }}
+    name: Test | 26.04 | clang | ${{ matrix.suite }}
     needs: build-2604-clang
     uses: ./.github/workflows/reusable-test.yml
     with:
       archive: ${{ needs.build-2604-clang.outputs.archive }}
-      os: ${{ matrix.os }}
-      cc: ${{ matrix.cc }}
-      reloc: ${{ matrix.reloc }}
+      cc: clang
+      runs-on: ubuntu-26.04
       suite: ${{ matrix.suite }}
-      dev-gcov: 0
     strategy:
       fail-fast: false
       matrix:
-        include:
-          # Ubuntu 26.04 clang
-          - {os: ubuntu-26.04, cc: clang, reloc: 0, suite: dist-vlt-0}
-          - {os: ubuntu-26.04, cc: clang, reloc: 0, suite: dist-vlt-1}
-          - {os: ubuntu-26.04, cc: clang, reloc: 0, suite: dist-vlt-2}
-          - {os: ubuntu-26.04, cc: clang, reloc: 0, suite: dist-vlt-3}
-          - {os: ubuntu-26.04, cc: clang, reloc: 0, suite: vltmt-0}
-          - {os: ubuntu-26.04, cc: clang, reloc: 0, suite: vltmt-1}
-          - {os: ubuntu-26.04, cc: clang, reloc: 0, suite: vltmt-2}
+        suite: [dist-vlt-0, dist-vlt-1, dist-vlt-2, dist-vlt-3, vltmt-0, vltmt-1, vltmt-2]
 
   test-2404-gcc:
-    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.reloc && 'reloc | ' || '' }} ${{ matrix.suite }}
+    name: Test | 24.04 | gcc | ${{ matrix.suite }}
     needs: build-2404-gcc
     uses: ./.github/workflows/reusable-test.yml
     with:
       archive: ${{ needs.build-2404-gcc.outputs.archive }}
-      os: ${{ matrix.os }}
-      cc: ${{ matrix.cc }}
-      reloc: ${{ matrix.reloc }}
+      cc: gcc
+      runs-on: ubuntu-24.04
       suite: ${{ matrix.suite }}
-      dev-gcov: 0
     strategy:
       fail-fast: false
       matrix:
-        include:
-          # Ubuntu 24.04 gcc
-          - {os: ubuntu-24.04, cc: gcc, reloc: 0, suite: dist-vlt-0}
-          - {os: ubuntu-24.04, cc: gcc, reloc: 0, suite: dist-vlt-1}
-          - {os: ubuntu-24.04, cc: gcc, reloc: 0, suite: dist-vlt-2}
-          - {os: ubuntu-24.04, cc: gcc, reloc: 0, suite: dist-vlt-3}
-          - {os: ubuntu-24.04, cc: gcc, reloc: 0, suite: vltmt-0}
-          - {os: ubuntu-24.04, cc: gcc, reloc: 0, suite: vltmt-1}
-          - {os: ubuntu-24.04, cc: gcc, reloc: 0, suite: vltmt-2}
+        suite: [dist-vlt-0, dist-vlt-1, dist-vlt-2, dist-vlt-3, vltmt-0, vltmt-1, vltmt-2]
 
   test-2404-clang:
-    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.reloc && 'reloc | ' || '' }} ${{ matrix.suite }}
+    name: Test | 24.04 | clang | ${{ matrix.suite }}
     needs: build-2404-clang
     uses: ./.github/workflows/reusable-test.yml
     with:
       archive: ${{ needs.build-2404-clang.outputs.archive }}
-      os: ${{ matrix.os }}
-      cc: ${{ matrix.cc }}
-      reloc: ${{ matrix.reloc }}
+      cc: clang
+      reloc: true  # Test with relocated installation
+      runs-on: ubuntu-24.04
       suite: ${{ matrix.suite }}
-      dev-gcov: 0
     strategy:
       fail-fast: false
       matrix:
-        include:
-          # Ubuntu 24.04 clang
-          - {os: ubuntu-24.04, cc: clang, reloc: 0, suite: dist-vlt-0}
-          - {os: ubuntu-24.04, cc: clang, reloc: 0, suite: dist-vlt-1}
-          - {os: ubuntu-24.04, cc: clang, reloc: 0, suite: dist-vlt-2}
-          - {os: ubuntu-24.04, cc: clang, reloc: 0, suite: dist-vlt-3}
-          - {os: ubuntu-24.04, cc: clang, reloc: 0, suite: vltmt-0}
-          - {os: ubuntu-24.04, cc: clang, reloc: 0, suite: vltmt-1}
-          - {os: ubuntu-24.04, cc: clang, reloc: 0, suite: vltmt-2}
+        suite: [dist-vlt-0, dist-vlt-1, dist-vlt-2, dist-vlt-3, vltmt-0, vltmt-1, vltmt-2]
 
   test-2204-gcc:
-    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.reloc && 'reloc | ' || '' }} ${{ matrix.suite }}
+    name: Test | 22.04 | gcc | ${{ matrix.suite }}
     needs: build-2204-gcc
     uses: ./.github/workflows/reusable-test.yml
     with:
       archive: ${{ needs.build-2204-gcc.outputs.archive }}
-      os: ${{ matrix.os }}
-      cc: ${{ matrix.cc }}
-      reloc: ${{ matrix.reloc }}
+      cc: gcc
+      runs-on: ubuntu-22.04
       suite: ${{ matrix.suite }}
-      dev-gcov: 0
     strategy:
       fail-fast: false
       matrix:
-        include:
-          # Ubuntu 22.04 gcc
-          - {os: ubuntu-22.04, cc: gcc, reloc: 0, suite: dist-vlt-0}
-          - {os: ubuntu-22.04, cc: gcc, reloc: 0, suite: dist-vlt-1}
-          - {os: ubuntu-22.04, cc: gcc, reloc: 0, suite: dist-vlt-2}
-          - {os: ubuntu-22.04, cc: gcc, reloc: 0, suite: dist-vlt-3}
-          - {os: ubuntu-22.04, cc: gcc, reloc: 0, suite: vltmt-0}
-          - {os: ubuntu-22.04, cc: gcc, reloc: 0, suite: vltmt-1}
-          - {os: ubuntu-22.04, cc: gcc, reloc: 0, suite: vltmt-2}
+        suite: [dist-vlt-0, dist-vlt-1, dist-vlt-2, dist-vlt-3, vltmt-0, vltmt-1, vltmt-2]
 
   lint-py:
     name: Lint Python

.github/workflows/contributor.yml

@@ -16,5 +16,5 @@ jobs:
     name: "'docs/CONTRIBUTORS' was signed"
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
       - run: test_regress/t/t_dist_contributors.py

.github/workflows/coverage.yml

@@ -13,6 +13,7 @@ on:
 
 permissions:
   contents: read
+  actions: read
 
 defaults:
   run:
@@ -38,15 +39,13 @@ jobs:
       (github.event_name == 'workflow_dispatch')
     uses: ./.github/workflows/reusable-build.yml
     with:
+      cc: gcc
+      dev-gcov: true
+      runs-on: ubuntu-24.04
       # For pull requests, build the head of the pull request branch, not the
       # merge commit, otherwise patch coverage would include the changes
       # between the root of the pull request and the target branch
       sha: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
-      os: ubuntu-24.04
-      os-name: linux
-      cc: gcc
-      dev-asan: 0
-      dev-gcov: 1
 
   test:
     name: Test | ${{ matrix.test }}${{ matrix.num }}
@@ -54,11 +53,10 @@ jobs:
     uses: ./.github/workflows/reusable-test.yml
     with:
       archive: ${{ needs.build.outputs.archive }}
-      os: ubuntu-24.04
       cc: gcc
-      reloc: 0
+      dev-gcov: true
+      runs-on: ubuntu-24.04
       suite: ${{ matrix.test }}${{ matrix.num }}
-      dev-gcov: 1
     strategy:
       fail-fast: false
       matrix:
@@ -74,7 +72,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
 
       - name: Download code coverage data
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c  # v8
@@ -121,7 +119,7 @@ jobs:
 
       - name: Unpack repository archive
         run: |
-          tar -x -z -f ${{ needs.build.outputs.archive }}
+          tar --zstd -x -f ${{ needs.build.outputs.archive }}
           ls -lsha
 
       - name: Download code coverage data

.github/workflows/docker.yml

@@ -39,7 +39,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
 
       - name: Extract context variables
         run: |
@@ -54,7 +54,7 @@ jobs:
 
       - name: Docker meta
         id: docker_meta
-        uses: docker/metadata-action@80c7e94dd9b9319bd5eb7a0e0fe9291e23a2a2e9  # v6
+        uses: docker/metadata-action@dc802804100637a589fabce1cb79ff13a1411302  # v6
         with:
           images: |
             ${{ vars.DOCKER_HUB_NAMESPACE }}/${{ env.image_name }}
@@ -64,21 +64,21 @@ jobs:
             type=raw,value=latest,enable=${{ inputs.add_latest_tag == true }}
 
       - name: Set up QEMU
-        uses: docker/setup-qemu-action@06116385d9baf250c9f4dcb4858b16962ea869c3  # v4
+        uses: docker/setup-qemu-action@96fe6ef7f33517b61c61be40b68a1882f3264fb8  # v4
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@d7f5e7f509e45cec5c76c4d5afdd7de93d0b3df5  # v4
+        uses: docker/setup-buildx-action@bb05f3f5519dd87d3ba754cc423b652a5edd6d2c  # v4
         with:
           buildkitd-flags: --debug
 
       - name: Login to Docker Hub
-        uses: docker/login-action@650006c6eb7dba73a995cc03b0b2d7f5ca915bee  # v4
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f  # v4
         with:
           username: ${{ secrets.DOCKER_HUB_USER }}
           password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}
 
       - name: Build and Push to Docker
-        uses: docker/build-push-action@f9f3042f7e2789586610d6e8b85c8f03e5195baf  # v7
+        uses: docker/build-push-action@53b7df96c91f9c12dcc8a07bcb9ccacbed38856a  # v7
         if: startsWith(github.ref, 'refs/tags/v') || github.event_name == 'workflow_dispatch'
         with:
           context: ${{ env.build_context }}

.github/workflows/format.yml

@@ -11,35 +11,44 @@ on:
 permissions:
   contents: write
 
+defaults:
+  run:
+    working-directory: repo
+
 jobs:
   format:
     runs-on: ubuntu-24.04
     name: Ubuntu 24.04 | format
-    env:
-      CI_OS_NAME: linux
-      CI_RUNS_ON: ubuntu-24.04
-      CI_COMMIT: ${{ github.sha }}
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
         with:
+          path: repo
           token: ${{ secrets.GITHUB_TOKEN }}
+
       - name: Install packages for build
-        env:
-          CI_BUILD_STAGE_NAME: build
         run: |
           sudo apt install clang-format-18 || \
           sudo apt install clang-format-18
           git config --global user.email "action@example.com"
           git config --global user.name "github action"
-      - name: Format code
+
+      - name: Configure
         run: |
           autoconf
           ./configure
-          make venv
+
+      - name: Set up Python venv
+        uses: ./repo/.github/actions/setup-venv
+        with:
+          save: ${{ github.ref == 'refs/heads/master' }}
+
+      - name: Format code
+        run: |
           source .venv/bin/activate
           make -j 4 format CLANGFORMAT=clang-format-18
           git status
+
       - name: Push
         run: |-
           if [ -n "$(git status --porcelain)" ]; then

.github/workflows/pages.yml

@@ -7,7 +7,7 @@ name: Pages
 on:
   push:
     branches: [master]
-    paths: ["ci/**", ".github/workflows"]
+    paths: ["ci/**", ".github/workflows/**"]
   workflow_dispatch:
   workflow_run:
     workflows: ["Code coverage", "RTLMeter"]
@@ -22,8 +22,11 @@ permissions:
 # Allow only one concurrent deployment, skipping runs queued between the run
 # in-progress and latest queued. However, do NOT cancel in-progress runs as we
 # want to allow these deployments to complete.
+# A skipped-upstream run does no work (see the build job's if:), so put it in its
+# own throwaway group: otherwise, as the newest queued run, it would cancel a
+# pending real run and then deploy nothing.
 concurrency:
-  group: "pages"
+  group: ${{ (github.event_name == 'workflow_run' && github.event.workflow_run.conclusion == 'skipped') && format('pages-skip-{0}', github.run_id) || 'pages' }}
   cancel-in-progress: false
 
 defaults:
@@ -34,11 +37,15 @@ jobs:
   build:
     name: Build content
     runs-on: ubuntu-24.04
+    # A skipped upstream run (e.g. Code coverage / RTLMeter on a branch push)
+    # still fires workflow_run; don't rebuild and redeploy for it. deploy and
+    # notify need this job, so they cascade-skip too.
+    if: ${{ github.event_name != 'workflow_run' || github.event.workflow_run.conclusion != 'skipped' }}
     outputs:
       pr-run-ids: ${{ steps.build.outputs.pr-run-ids }}
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
       - name: Build pages
         id: build
         env:
@@ -58,9 +65,16 @@ jobs:
     runs-on: ubuntu-24.04
     environment:
       name: github-pages
-      url: ${{ steps.deployment.outputs.page_url }}
+      url: ${{ steps.deploy-2.outputs.page_url || steps.deploy-1.outputs.page_url }}
     steps:
+      # GitHub's Pages backend intermittently fails a deployment mid-sync, retry
       - name: Deploy to GitHub Pages
+        id: deploy-1
+        continue-on-error: true
+        uses: actions/deploy-pages@cd2ce8fcbc39b97be8ca5fce6e763baed58fa128  # v5
+      - name: Deploy to GitHub Pages (retry)
+        id: deploy-2
+        if: steps.deploy-1.outcome == 'failure'
         uses: actions/deploy-pages@cd2ce8fcbc39b97be8ca5fce6e763baed58fa128  # v5
 
   notify:
@@ -70,7 +84,7 @@ jobs:
     if: ${{ github.repository == 'verilator/verilator' }}
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
       # Use the Verilator CI app to post the comment
       - name: Generate access token
         id: generate-token

.github/workflows/reusable-build.yml

@@ -7,37 +7,47 @@ name: reusable-build
 on:
   workflow_call:
     inputs:
+      cc:
+        description: "Compiler to use: 'gcc' or 'clang'"
+        required: true
+        type: string
+      ccwarn:
+        description: "Build Verilator with warnings treated as errors (--enable-ccwarn)"
+        required: false
+        default: true
+        type: boolean
+      dev-asan:
+        description: "Build Verilator with the address sanitizer (--enable-dev-asan)"
+        required: false
+        default: false
+        type: boolean
+      dev-gcov:
+        description: "Build Verilator with gcov instrumentation (--enable-dev-gcov)"
+        required: false
+        default: false
+        type: boolean
+      install:
+        description: "Archive the Verilator installation, not the repo tree"
+        required: false
+        default: false
+        type: boolean
+      runs-on:
+        description: "Runner to build on, e.g. ubuntu-24.04"
+        required: true
+        type: string
       sha:
         description: "Commit SHA to build"
         required: true
         type: string
-      os:  # e.g. ubuntu-24.04
-        required: true
-        type: string
-      cc: # 'clang' or 'gcc'
-        required: true
-        type: string
-      os-name: # 'linux' or 'osx'
-        required: true
-        type: string
-      dev-asan:
-        required: true
-        type: number
-      dev-gcov:
-        required: true
-        type: number
     outputs:
       archive:
-        description: "Name of the built repository archive artifact"
+        description: "Name of the built archive artifact"
         value: ${{ jobs.build.outputs.archive }}
 
 env:
-  CI_OS_NAME: ${{ inputs.os-name }}
-  CCACHE_COMPRESS: 1
+  CACHE_BASE_KEY: build-${{ inputs.runs-on }}-${{ inputs.cc }}${{ inputs.ccwarn && '-ccwarn' || '' }}${{ inputs.dev-asan && '-asan' || '' }}${{ inputs.dev-gcov && '-gcov' || '' }}
+  CCACHE_COMPILERCHECK: content
   CCACHE_DIR: ${{ github.workspace }}/.ccache
-  CCACHE_LIMIT_MULTIPLE: 0.95
-  INSTALL_DIR: ${{ github.workspace }}/install
-  RELOC_DIR: ${{ github.workspace }}/relloc
 
 defaults:
   run:
@@ -48,26 +58,28 @@ jobs:
 
   build:
     name: Build
-    runs-on: ${{ inputs.os }}
+    runs-on: ${{ inputs.runs-on }}
     outputs:
       archive: ${{ steps.create-archive.outputs.archive }}
-    env:
-      CI_BUILD_STAGE_NAME: build
-      CI_DEV_ASAN: ${{ inputs.dev-asan }}
-      CI_DEV_GCOV: ${{ inputs.dev-gcov }}
-      CI_RUNS_ON: ${{ inputs.os }}
-      CXX: ${{ inputs.cc == 'clang' && 'clang++' || 'g++' }}
-      CACHE_BASE_KEY: build-${{ inputs.os }}-${{ inputs.cc }}
-      CCACHE_MAXSIZE: 1000M  # Per build matrix entry (* 5 = 5000M in total)
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
         with:
           path: repo
           ref: ${{ inputs.sha }}
-          fetch-depth: ${{ inputs.dev-gcov && '0' || '1' }}  # Coverage flow needs full history
+          # Coverage needs full history; install needs it for the 'git describe'
+          # behind 'verilator --version'
+          fetch-depth: ${{ (inputs.install || inputs.dev-gcov) && '0' || '1' }}
+
+      - name: Configure ccache
+        run: |
+          # ccache is unreliable on macOS, and does nothing with 'gcc --coverage'
+          if [ "${{ startsWith(inputs.runs-on, 'macos') }}" = true ] || [ "${{ inputs.dev-gcov }}" = true ]; then
+            echo "CCACHE_DISABLE=1" >> "$GITHUB_ENV"
+          fi
 
       - name: Cache $CCACHE_DIR
+        if: ${{ env.CCACHE_DISABLE != '1' }}
         uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9  # v5
         env:
           CACHE_KEY: ${{ env.CACHE_BASE_KEY }}-ccache
@@ -75,25 +87,44 @@ jobs:
           path: ${{ env.CCACHE_DIR }}
           key: ${{ env.CACHE_KEY }}-${{ inputs.sha }}
           restore-keys: |
-            ${{ env.CACHE_KEY }}-
+            ${{ env.CACHE_KEY }}
 
       - name: Install packages for build
-        run: ./ci/ci-install.bash
+        run: ./ci/ci-install.bash build
 
       - name: Build
-        run: ./ci/ci-script.bash
+        run: |
+          ./ci/ci-build.bash \
+            --prefix ${{ github.workspace }}/install \
+            --compiler ${{ inputs.cc }} \
+            --light-debug \
+            ${{ inputs.ccwarn && '--ccwarn' || '' }} \
+            ${{ inputs.dev-asan && '--asan' || '' }} \
+            ${{ inputs.dev-gcov && '--gcov' || '' }}
 
-      - name: Create repository archive
+      - name: Install
+        if: ${{ inputs.install }}
+        run: make install
+
+      - name: Create archive
         id: create-archive
         working-directory: ${{ github.workspace }}
         run: |
-          # Name of the archive must be unique based on the build parameters
-          ARCHIVE=verilator-${{ inputs.sha }}-${{ inputs.os }}-${{ inputs.cc }}-${{ inputs.dev-asan }}-${{ inputs.dev-gcov }}.tar.gz
-          tar --posix -c -z -f $ARCHIVE repo
+          # Archive name, unique per build; flavour tags mark non-default builds
+          ARCHIVE="verilator-${{ inputs.sha }}-${{ inputs.runs-on }}-${{ inputs.cc }}"
+          ARCHIVE="$ARCHIVE${{ inputs.ccwarn && '-ccwarn' || '' }}"
+          ARCHIVE="$ARCHIVE${{ inputs.dev-asan && '-asan' || '' }}"
+          ARCHIVE="$ARCHIVE${{ inputs.dev-gcov && '-gcov' || '' }}"
+          ARCHIVE="$ARCHIVE.tar.zst"
+          # zstd compresses faster than gzip and decompresses far faster in the many downstream jobs
+          ZSTD_NBTHREADS=0 tar --posix --zstd -c -f "$ARCHIVE" ${{ inputs.install && 'install' || 'repo' }}
           echo "archive=$ARCHIVE" >> "$GITHUB_OUTPUT"
 
-      - name: Upload repository archive
+      - name: Upload archive
         uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7
         with:
           path: ${{ github.workspace }}/${{ steps.create-archive.outputs.archive }}
           name: ${{ steps.create-archive.outputs.archive }}
+          overwrite: true
+          # Archive is already zstd-compressed; skip upload-artifact's zip pass
+          compression-level: 0

.github/workflows/reusable-lint-py.yml

@@ -7,14 +7,6 @@ name: reusable-lint-py
 on:
   workflow_call:
 
-env:
-  CI_OS_NAME: linux
-  CI_BUILD_STAGE_NAME: build
-  CI_RUNS_ON: ubuntu-22.04
-  CCACHE_COMPRESS: 1
-  CCACHE_DIR: ${{ github.workspace }}/.ccache
-  CCACHE_LIMIT_MULTIPLE: 0.95
-
 defaults:
   run:
     shell: bash
@@ -27,23 +19,22 @@ jobs:
     name: Sub-lint | Python
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
         with:
           path: repo
 
-      - name: Install packages for build
-        run: ./ci/ci-install.bash
+      - name: Install dependencies
+        run: ./ci/ci-install.bash lint-py
 
       - name: Configure
         run: |
           autoconf
           ./configure --enable-longtests --enable-ccwarn
 
-      - name: Install python dependencies
-        run: |
-          sudo apt install python3-clang || \
-          sudo apt install python3-clang
-          make venv
+      - name: Set up Python venv
+        uses: ./repo/.github/actions/setup-venv
+        with:
+          save: ${{ github.ref == 'refs/heads/master' }}
 
       - name: Lint
         run: |-

.github/workflows/reusable-rtlmeter-build.yml

@@ -1,96 +0,0 @@
----
-# DESCRIPTION: Github actions config
-# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
-
-name: reusable-rtlmeter-build
-
-on:
-  workflow_call:
-    inputs:
-      runs-on:
-        description: "Runner to use, e.g.: ubuntu-24.04"
-        type: string
-        required: true
-      cc:
-        description: "Compiler to use: 'gcc' or 'clang'"
-        type: string
-        required: true
-      sha:
-        description: "Git SHA to build"
-        type: string
-        required: true
-    outputs:
-      archive:
-        description: "Name of the built installation archive artifact"
-        value: ${{ jobs.build.outputs.archive }}
-
-defaults:
-  run:
-    shell: bash
-
-env:
-  CCACHE_DIR: ${{ github.workspace }}/ccache
-  CCACHE_MAXSIZE: 512M
-
-jobs:
-  build:
-    name: Build
-    runs-on: ${{ inputs.runs-on }}
-    outputs:
-      archive: ${{ steps.create-archive.outputs.archive }}
-    steps:
-      - name: Install dependencies
-        run: |
-          echo "path-exclude /usr/share/doc/*"  | sudo tee -a /etc/dpkg/dpkg.cfg.d/01_nodoc
-          echo "path-exclude /usr/share/man/*"  | sudo tee -a /etc/dpkg/dpkg.cfg.d/01_nodoc
-          echo "path-exclude /usr/share/info/*" | sudo tee -a /etc/dpkg/dpkg.cfg.d/01_nodoc
-          sudo apt update || \
-          sudo apt update
-          sudo apt install ccache mold help2man libfl-dev libjemalloc-dev libsystemc-dev || \
-          sudo apt install ccache mold help2man libfl-dev libjemalloc-dev libsystemc-dev
-
-      - name: Use saved ccache
-        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9  # v5
-        with:
-          path: ccache
-          key: rtlmeter-build-ccache-${{ inputs.runs-on }}-${{ inputs.cc }}-${{ inputs.sha }}-${{ github.run_id }}-${{ github.run_attempt }}
-          restore-keys: |
-            rtlmeter-build-ccache-${{ inputs.runs-on }}-${{ inputs.cc }}-${{ inputs.sha }}-${{ github.run_id }}
-            rtlmeter-build-ccache-${{ inputs.runs-on }}-${{ inputs.cc }}-${{ inputs.sha }}
-            rtlmeter-build-ccache-${{ inputs.runs-on }}-${{ inputs.cc }}
-
-      - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
-        with:
-          path: repo
-          ref: ${{ inputs.sha }}
-          fetch-depth: 0 # Required for 'git describe' used for 'verilator --version'
-
-      - name: Configure
-        working-directory: repo
-        run: |
-          autoconf
-          ./configure --prefix=${{ github.workspace }}/install CXX=${{ inputs.cc == 'clang' && 'clang++' || 'g++' }}
-
-      - name: Make
-        working-directory: repo
-        run: make -j $(nproc)
-
-      - name: Install
-        working-directory: repo
-        run: make install
-
-      - name: Tar up installation
-        id: create-archive
-        run: |
-          SHA=$(git -C repo rev-parse HEAD)
-          ARCHIVE=verilator-$SHA-rtlmeter-${{ inputs.runs-on }}-${{ inputs.cc }}.tar.gz
-          tar --posix -c -z -f $ARCHIVE install
-          echo "archive=$ARCHIVE" >> $GITHUB_OUTPUT
-
-      - name: Upload Verilator installation archive
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7
-        with:
-          path: ${{ steps.create-archive.outputs.archive }}
-          name: ${{ steps.create-archive.outputs.archive }}
-          overwrite: true

.github/workflows/reusable-rtlmeter-run.yml

@@ -20,11 +20,11 @@ on:
         type: string
         required: true
       verilator-archive-new:
-        description: "Name of the installation archive artifact from reusable-rtlmeter-build, new version"
+        description: "Name of the installation archive artifact from reusable-build, new version"
         type: string
         required: true
       verilator-archive-old:
-        description: "Name of the installation archive artifact from reusable-rtlmeter-build, old version"
+        description: "Name of the installation archive artifact from reusable-build, old version"
         type: string
         required: false
         default: ""
@@ -53,8 +53,8 @@ defaults:
     shell: bash
 
 env:
-  CCACHE_DIR: ${{ github.workspace }}/ccache
-  CCACHE_MAXSIZE: 512M
+  # RTLMeter measures compile/execute times, so caching must stay off to keep
+  # timings representative; ccache is still on PATH but acts as a pass-through
   CCACHE_DISABLE: 1
 
 jobs:
@@ -73,7 +73,7 @@ jobs:
           sudo apt install ccache mold libfl-dev libjemalloc-dev libsystemc-dev
 
       - name: Checkout RTLMeter
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
         with:
           repository: "verilator/rtlmeter"
           path: rtlmeter
@@ -82,14 +82,6 @@ jobs:
         working-directory: rtlmeter
         run: make venv
 
-      - name: Use saved ccache
-        if: ${{ env.CCACHE_DISABLE == 0 }}
-        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9  # v5
-        with:
-          path: ${{ env.CCACHE_DIR }}
-          key: rtlmeter-run-ccache-${{ inputs.runs-on }}-${{ inputs.cc }}-${{ inputs.cases }}-${{ inputs.compileArgs }}-${{ github.run_id }}-${{ github.run_attempt }}
-          restore-keys: rtlmeter-run-ccache-${{ inputs.runs-on }}-${{ inputs.cc }}-${{ inputs.cases }}-${{ inputs.compileArgs }}
-
       ########################################################################
       # Run with new Verilator
       ########################################################################
@@ -101,7 +93,7 @@ jobs:
 
       - name: Unpack Verilator installation archive - new
         run: |
-          tar -x -z -f ${{ inputs.verilator-archive-new }}
+          tar --zstd -x -f ${{ inputs.verilator-archive-new }}
           mv install verilator-new
 
       - name: Compile cases - new
@@ -164,7 +156,7 @@ jobs:
       - name: Unpack Verilator installation archive - old
         if: ${{ inputs.verilator-archive-old != '' }}
         run: |
-          tar -x -z -f ${{ inputs.verilator-archive-old }}
+          tar --zstd -x -f ${{ inputs.verilator-archive-old }}
           mv install verilator-old
 
       - name: Compile cases - old

.github/workflows/reusable-test.yml

@@ -11,29 +11,37 @@ on:
         description: "Name of the repository archive artifact from reusable-build"
         required: true
         type: string
-      os:  # e.g. ubuntu-24.04
-        required: true
-        type: string
-      cc:  # gcc or clang
-        required: true
-        type: string
-      reloc:  # 0 or 1
-        required: true
-        type: number
-      suite:  # e.g. dist-vlt-0
+      cc:
+        description: "Compiler to use: 'gcc' or 'clang'"
         required: true
         type: string
       dev-gcov:
+        description: "Collect gcov coverage data from the test run"
+        required: false
+        default: false
+        type: boolean
+      reloc:
+        description: "Relocate the installation before testing"
+        required: false
+        default: false
+        type: boolean
+      runs-on:
+        description: "Runner to test on, e.g. ubuntu-24.04"
         required: true
-        type: number
+        type: string
+      suite:
+        description: "Test suite to run, e.g. dist-vlt-0"
+        required: true
+        type: string
+
+permissions:
+  contents: read
+  actions: read
 
 env:
-  CI_OS_NAME: linux
-  CCACHE_COMPRESS: 1
+  CCACHE_COMPILERCHECK: content
   CCACHE_DIR: ${{ github.workspace }}/.ccache
-  CCACHE_LIMIT_MULTIPLE: 0.95
-  INSTALL_DIR: ${{ github.workspace }}/install
-  RELOC_DIR: ${{ github.workspace }}/relloc
+  CXX: ${{ inputs.cc == 'clang' && 'clang++' || 'g++' }}
 
 defaults:
   run:
@@ -43,15 +51,8 @@ defaults:
 jobs:
 
   test:
-    runs-on: ${{ inputs.os }}
+    runs-on: ${{ inputs.runs-on }}
     name: Test
-    env:
-      CI_BUILD_STAGE_NAME: test
-      CI_RUNS_ON: ${{ inputs.os }}
-      CI_RELOC: ${{inputs.reloc }}
-      CXX: ${{ inputs.cc == 'clang' && 'clang++' || 'g++' }}
-      CACHE_BASE_KEY: test-${{ inputs.os }}-${{ inputs.cc }}-${{inputs.reloc }}-${{ inputs.suite }}
-      CCACHE_MAXSIZE: 100M  # Per build per suite (* 5 * 5 = 2500M in total)
     steps:
 
       - name: Download repository archive
@@ -63,32 +64,43 @@ jobs:
       - name: Unpack repository archive
         working-directory: ${{ github.workspace }}
         run: |
-          tar -x -z -f ${{ inputs.archive }}
+          tar --zstd -x -f ${{ inputs.archive }}
           ls -lsha
 
-      - name: Cache $CCACHE_DIR
-        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9  # v5
-        env:
-          CACHE_KEY: ${{ env.CACHE_BASE_KEY }}-ccache2
+      - name: Configure ccache
+        run: |
+          # ccache is unreliable on macOS, and does nothing with 'gcc --coverage'
+          if [ "${{ startsWith(inputs.runs-on, 'macos') }}" = true ] || [ "${{ inputs.dev-gcov }}" = true ]; then
+            echo "CCACHE_DISABLE=1" >> "$GITHUB_ENV"
+          fi
+
+      # Test-job ccache is stored as an artifact, not actions/cache
+      - name: Restore ccache
+        id: ccache
+        if: ${{ env.CCACHE_DISABLE != '1' }}
+        uses: ./repo/.github/actions/artifact-cache
         with:
+          mode: restore
           path: ${{ env.CCACHE_DIR }}
-          key: ${{ env.CACHE_KEY }}-${{ github.sha }}
-          restore-keys: |
-            ${{ env.CACHE_KEY }}-
+          key: ccache-${{ inputs.runs-on }}-${{ inputs.cc }}-${{ inputs.suite }}
 
       - name: Install test dependencies
         run: |
-          ./ci/ci-install.bash
-          make venv
+          ./ci/ci-install.bash test
+
+      - name: Set up Python venv
+        uses: ./repo/.github/actions/setup-venv
+        with:
+          save: ${{ github.ref == 'refs/heads/master' }}
 
       - name: Test
         id: run-test
         continue-on-error: true
-        env:
-          TESTS: ${{ inputs.suite }}
         run: |
           source .venv/bin/activate
-          ./ci/ci-script.bash
+          ./ci/ci-test.bash \
+            --suite ${{ inputs.suite }} \
+            ${{ inputs.reloc && format('--reloc {0}/reloc', github.workspace) || '' }}
 
       - name: Combine code coverage data
         if: ${{ inputs.dev-gcov }}
@@ -104,6 +116,16 @@ jobs:
           path: ${{ github.workspace }}/repo/obj_coverage/verilator-${{ inputs.suite }}.info
           name: code-coverage-${{ inputs.suite }}
 
+      - name: Save ccache
+        if: ${{ env.CCACHE_DISABLE != '1' && !cancelled() }}
+        uses: ./repo/.github/actions/artifact-cache
+        with:
+          mode: save
+          path: ${{ env.CCACHE_DIR }}
+          key: ${{ steps.ccache.outputs.key }}
+          # Keep master's cache around longer; PR/branch caches churn faster
+          retention-days: ${{ github.ref == 'refs/heads/master' && 7 || 3 }}
+
       - name: Fail job if a test failed
         if: ${{ steps.run-test.outcome == 'failure' && !cancelled() }}
         run: |-

.github/workflows/rtlmeter.yml

@@ -45,7 +45,7 @@ jobs:
       cases: ${{ steps.cases.outputs.cases }}
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
 
       - name: Startup
         id: start
@@ -65,39 +65,47 @@ jobs:
   build-gcc-new:
     name: Build New Verilator - GCC
     needs: start
-    uses: ./.github/workflows/reusable-rtlmeter-build.yml
+    uses: ./.github/workflows/reusable-build.yml
     with:
-      runs-on: ubuntu-24.04
       cc: gcc
+      ccwarn: false
+      install: true
+      runs-on: ubuntu-24.04
       sha: ${{ github.sha }}
 
   build-clang-new:
     name: Build New Verilator - Clang
     needs: start
-    uses: ./.github/workflows/reusable-rtlmeter-build.yml
+    uses: ./.github/workflows/reusable-build.yml
     with:
-      runs-on: ubuntu-24.04
       cc: clang
+      ccwarn: false
+      install: true
+      runs-on: ubuntu-24.04
       sha: ${{ github.sha }}
 
   build-gcc-old:
     name: Build Old Verilator - GCC
     needs: start
     if: ${{ needs.start.outputs.old-sha != '' }}
-    uses: ./.github/workflows/reusable-rtlmeter-build.yml
+    uses: ./.github/workflows/reusable-build.yml
     with:
-      runs-on: ubuntu-24.04
       cc: gcc
+      ccwarn: false
+      install: true
+      runs-on: ubuntu-24.04
       sha: ${{ needs.start.outputs.old-sha }}
 
   build-clang-old:
     name: Build Old Verilator - Clang
     needs: start
     if: ${{ needs.start.outputs.old-sha != '' }}
-    uses: ./.github/workflows/reusable-rtlmeter-build.yml
+    uses: ./.github/workflows/reusable-build.yml
     with:
-      runs-on: ubuntu-24.04
       cc: clang
+      ccwarn: false
+      install: true
+      runs-on: ubuntu-24.04
       sha: ${{ needs.start.outputs.old-sha }}
 
   run-gcc:
@@ -208,7 +216,7 @@ jobs:
         run: echo "tags=$(jq -r 'keys | map(sub("^run-"; "")) | join(" ")' <<< '${{ toJSON(needs) }}')" >> "$GITHUB_OUTPUT"
 
       - name: Checkout RTLMeter
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
         with:
           repository: "verilator/rtlmeter"
           path: rtlmeter
@@ -298,7 +306,7 @@ jobs:
           repositories: verilator-rtlmeter-results
           permission-contents: write
       - name: Checkout verilator-rtlmeter-results
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
         with:
           repository: "verilator/verilator-rtlmeter-results"
           token: ${{ steps.generate-token.outputs.token }}
@@ -331,7 +339,7 @@ jobs:
       actions: read
     steps:
       - name: Checkout RTLMeter
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
         with:
           repository: "verilator/rtlmeter"
           path: rtlmeter
@@ -341,7 +349,7 @@ jobs:
         run: make venv
 
       - name: Checkout Verilator
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
         with:
           path: verilator
 

CMakeLists.txt

@@ -16,7 +16,7 @@ cmake_minimum_required(VERSION 3.15)
 cmake_policy(SET CMP0091 NEW) # Use MSVC_RUNTIME_LIBRARY to select the runtime
 project(
     Verilator
-    VERSION 5.050
+    VERSION 5.051
     HOMEPAGE_URL https://verilator.org
     LANGUAGES CXX
 )
@@ -155,11 +155,12 @@ install(
 foreach(
     program
     verilator
-    verilator_gantt
     verilator_ccache_report
+    verilator_coverage
     verilator_difftree
-    verilator_profcfunc
+    verilator_gantt
     verilator_includer
+    verilator_profcfunc
 )
     install(PROGRAMS bin/${program} TYPE BIN)
 endforeach()

Changes

@@ -10,6 +10,125 @@ The changes in each Verilator version are described below.  The
 contributors that suggested or implemented a given issue are shown in []. Thanks!
 
 
+Verilator 5.051 devel
+==========================
+
+**Important:**
+
+* Verilator now supports UVM 2020-3.2; see (#1538) for limitations.
+
+**Other:**
+
+* Add comments as a branch description in coverage .info files (#7843). [Eryk Szpotanski]
+* Add --enable-light-debug configure option (#7886). [Geza Lore, Testorrent USA, Inc.]
+* Add user-provided DPI-C function declarations (#7626) (#7893). [Jakub Michalski]
+* Add error on static virtual functions (#7932). [Igor Zaworski, Antmicro Ltd.]
+* Add error when scalar is passed to array task argument (#7948). [Pawel Klopotek]
+* Add MULTIDRIVENPROC warning for signals driven by multiple plain always blocks (#7968). [Aisha]
+* Add FSM arc and state coverage to verilator_coverage .info output (#7972) (#7973). [Igor Zaworski, Antmicro Ltd.]
+* Add SIMILARNAME warning when variables have names that only differ in lexical case (#7992) (#8020). [Paul Campbell]
+* Add `+verilator+assert+lock` to ignore RTL assert control statements (#8086). [Sumanth Kadiyala]
+* Support embedded covergroup member references (#7749) (#8015). [Marco Bartoli]
+* Support a sequence used as an event control (#7797) (#7846). [Yilou Wang]
+* Support `[\*N:$]` consecutive repetition (#7940). [Artur Bieniek, Antmicro Ltd.]
+* Support dynamic containers in unique constraints (#7947). [Adam Kostrzewski, Antmicro Ltd.]
+* Support delayed tristate gates (#7960) (#7961). [Patrick Creighton]
+* Support `default clocking` (#7984). [Kamil Danecki, Antmicro Ltd.]
+* Support embedded covergroup clocking events (#8028). [Marco Bartoli]
+* Support `weak`/`strong` keywords in property expressions (#8054). [Artur Bieniek, Antmicro Ltd.]
+* Support class handle covergroup arguments (#8071). [Marco Bartoli]
+* Optimize random initialization. [Geza Lore, Testorrent USA, Inc.]
+* Optimize more always blocks in DFG (#7775). [Geza Lore, Testorrent USA, Inc.]
+* Optimize assertion NFAs using bit-vector ring buffers (#7885). [Artur Bieniek, Antmicro Ltd.]
+* Optimize VPI symbol registration and scope construction (#7936). [Nick Brereton]
+* Optimize bounded always properties using ring buffers (#8061) (#8092). [Artur Bieniek, Antmicro Ltd.]
+* Optimize VL_WORDS_I/VL_BYTES_I (#8095). [Geza Lore, Testorrent USA, Inc.]
+* Optimize temporary insertion for single bit replicates in DFG (#8110). [Geza Lore, Testorrent USA, Inc.]
+* Fix $finish continuing event loop (#7267) (#7950). [Artur Bieniek, Antmicro Ltd.]
+* Fix $display accepting streaming concat arguments (#7663) (#7890). [Jaeuk Lee]
+* Fix DFG misoptimizing bound checks (#7755). [Jakub Michalski]
+* Fix unique0 case side effects (#7787). [Pawel Klopotek]
+* Fix mid-window disable iff (#7792) (#7869). [Yilou Wang]
+* Fix cleaning purity cache after assertions. [Geza Lore, Testorrent USA, Inc.]
+* Fix uncaught type error leading to invalid C++ output (#7814). [Geza Lore, Testorrent USA, Inc.]
+* Fix internal error for coverpoints that reference a covergroup formal parameter (#7853 partial) (#7889). [Matthew Ballance]
+* Fix immediate disable of fork join branches (#7856) (#7931). [Marco Bartoli]
+* Fix self-disable of named blocks with forks (Part of #7857) (#7996) (#8006). [Marco Bartoli]
+* Fix clang++ ambiguous overload of '==' operator (#7863). [Pawel Kojma, Antmicro Ltd.]
+* Fix heap-use-after-free in `VlRNG::VlRNG()` (#7865). [Dragon-Git]
+* Fix mixed-width inside and dist range bounds failing randomization (#7875). [Yilou Wang]
+* Fix solve-before over array variables failing randomization (#7876). [Yilou Wang]
+* Fix scoped randomize with array members under rand_mode (#7877). [Yilou Wang]
+* Fix dist constraint on a frozen variable failing randomization (#7878). [Yilou Wang]
+* Fix range delays with parameter bounds (#7882). [Artur Bieniek, Antmicro Ltd.]
+* Fix --coverage on labeled inline assert/cover property (#7898) (#7904). [Patrick Creighton]
+* Fix memory leak in VerilatedFst::close() (#7899). [Jakub Michalski]
+* Fix spurious FSM COVERIGN on comparisons (#7900) (#7908). [Yogish Sekhar]
+* Fix independent force of multiply instantiated signals (#7905). [Artur Bieniek, Antmicro Ltd.]
+* Fix release of forced port nets (#7907) (#7901). [Artur Bieniek, Antmicro Ltd.]
+* Fix randomization of unreferenced rand members of unpacked structs (#7910) (#7911). [Philip Axer]
+* Fix VL_TO_STRING function for array of structs (#7912). [Kornel Uriasz, Antmicro Ltd.]
+* Fix queues falling into wrong template spec (#7914). [Adam Kostrzewski, Antmicro Ltd.]
+* Fix type resolution when a local name shadows a type name (#7915). [Pawel Klopotek]
+* Fix crash streaming an unpacked array of unpacked structs (#7917). [Nick Brereton]
+* Fix streaming concat as output-port lvalue into unpacked struct (#7918). [Nick Brereton]
+* Fix dropping variable writes across opaque calls (#7921) (#7933). [Philip Axer]
+* Fix dynamic array handling in solve...before (#7922). [Kornel Uriasz, Antmicro Ltd.]
+* Fix unlinked error with function call in derived class parameter (#7923). [Mateusz Gancarz, Antmicro Ltd.]
+* Fix scheduling of variables written in non-inlined functions in suspendable processes (#7924). [Igor Zaworski, Antmicro Ltd.]
+* Fix class parameter resolution (#7935).
+* Fix FSM detection of coverage-only branches (#7941) (#7942). [Patrick Creighton]
+* Fix use-after-free in V3LinkDotIfaceCapture (#7943). [Nick Brereton]
+* Fix sampled-value clocks in repeated assertions (#7944). [Artur Bieniek, Antmicro Ltd.]
+* Fix queued $finish/$stop request thread ordering (#7946 prep) (#7952). [Yilou Wang]
+* Fix DFG nested shifts with overflowing shift amount (#7955) (#7977).
+* Fix timing controls in interface tasks called via virtual interface (#7959). [Yilou Wang]
+* Fix lambda parameter types in queue min and max (#7962). [Bartosz Skorowski]
+* Fix solve-before dropping all soft constraints in randomize() (#7963). [Yilou Wang]
+* Fix generic interface param resolution in module/cell parameterization (#7970) (#7971). [David Garau]
+* Fix lost writes when select width exceeds variable width (#7975). [Bartosz Skorowski]
+* Fix $fgets being mis-optimized away (#7976). [G-A. Kamendje]
+* Fix SYNCASYNCNET false positive with changed non-edge logic (#7980). [Oron Port]
+* Fix variable scope in unique on dynamic array (#7981). [Kornel Uriasz, Antmicro Ltd.]
+* Fix table optimization causing not contextually convertible to bool error (#7983). [Jakub Michalski]
+* Fix wait fork trigger temporary split across generated functions (#7985) (#7986). [Marco Brambilla]
+* Fix randc cycling in a class that also uses solve...before (#7991 partial) (#8055). [Yilou Wang]
+* Fix randomize() with a user variable named 'item' (#7993) (#7994).
+* Fix UNSATCONSTR reporting constraint indices above 9 (#7995). [Yilou Wang]
+* Fix MULTIDRIVEN/PROC warning suppression via lint_off (#8000). [Gilberto Abram]
+* Fix force not substituted into an unpacked array index (#8002).
+* Fix dist weights ignored when an item is not a literal (#8003).
+* Fix error when forcing an array element read at a run-time index (#8004).
+* Fix FSM coverage on empty reset branches (#8005) (#8064). [Yogish Sekhar]
+* Fix missing verilator_coverage in cmake install (#8008) (#8011).
+* Fix dist inside a foreach nested in a constraint if (#8016).
+* Fix gcov dump on warnings discarding later coverage counts (#8017). [Yilou Wang]
+* Fix unique constraint crash, guards, and size (#8018).
+* Fix Linux peak memory stat to use VmHWM (#8022) (#8070). [Tyrone Marhguy]
+* Fix assignment pattern key constant expressions (#8029) (#8030). [Josep Sans]
+* Fix skipping optimization for unpacked data types (#8031). [Kornel Uriasz, Antmicro Ltd.]
+* Fix gate deduplication with function arguments (#8038). [JOTEGO]
+* Fix conditional expression with parameterized classes (#8039). [Pawel Klopotek, Antmicro Ltd.]
+* Fix array size references in constraints (#8040). [Kornel Uriasz, Antmicro Ltd.]
+* Fix mid-range consecutive repetition rejects (#8041). [Artur Bieniek, Antmicro Ltd.]
+* Fix write access to dynamic arrays (#8043). [Bartosz Skorowski, Antmicro Ltd.]
+* Fix nondeterminism in trace stage (#8046). [Sumanth Kadiyala]
+* Fix force helpers in multiply instantiated modules (#8047). [Artur Bieniek, Antmicro Ltd.]
+* Fix pin to non-existent port with PINNOTFOUND suppressed (#8051) (#8052). [Nikolai Kumar]
+* Fix wildcard equality against a 4-state constant in an assertion (#8056) (#8057). [Nikolai Kumar]
+* Fix untyped datatype error on sampling functions with property arguments (#8060). [Artur Bieniek, Antmicro Ltd.]
+* Fix VPI cbValueChange for 1-bit select (#8063). [Bartłomiej Chmiel, Antmicro Ltd.]
+* Fix skipping non-constrained enum constraining when inside object of other class (#8075). [Kornel Uriasz, Antmicro Ltd.]
+* Fix unintended side-effect insertion on associative array read (#8077). [Adam Kostrzewski, Antmicro Ltd.]
+* Fix undefined symbol solver error (#8080). [Igor Zaworski, Antmicro Ltd.]
+* Fix unpacked array element force with procedural assign (#8084) (#8085). [Nikolai Kumar]
+* Fix hierarchical class scope resolution (#8094). [Artur Bieniek, Antmicro Ltd.]
+* Fix the clang compilation using precompiled headers (#8105). [Demin Han]
+* Fix invalid typedef (#8106). [Adam Kostrzewski, Antmicro Ltd.]
+* Fix R/W references to random builtin function seeds (#8112). [Geza Lore, Testorrent USA, Inc.]
+* Fix COVERIGN on SVA goto repetition (#8118). [Artur Bieniek, Antmicro Ltd.]
+
+
 Verilator 5.050 2026-07-01
 ==========================
 
@@ -5738,7 +5857,7 @@ Verilator 3.104 2003-04-30
 **Major:**
 
 * Indicate direction of ports with VL_IN and VL_OUT.
-* Allow $c32, etc, to specify width of the $c statement for VCS.
+* Allow $c32, etc, to specify width of the $c statement.
 * Numerous performance improvements, worth about 25%
 
 **Minor:**

Makefile.in

@@ -536,6 +536,7 @@ PY_PROGRAMS = \
   src/vlcovgen \
   test_regress/*.py \
   test_regress/t/*.pf \
+  test_regress/t/randomize_solver_tamper.py \
 
 # Python files, subject to format but not lint
 PY_FILES = \

bin/verilator

@@ -636,6 +636,7 @@ description of these arguments.
 
 =for VL_SPHINX_EXTRACT "_build/gen/args_verilated.rst"
 
+     +verilator+assert+lock                Lock assertion status changes at startup
      +verilator+coverage+file+<filename>   Set coverage output filename
      +verilator+debug                      Enable debugging
      +verilator+debugi+<value>             Enable debugging at a level

ci/ci-build.bash

@@ -0,0 +1,90 @@
+#!/usr/bin/env bash
+# DESCRIPTION: Verilator: CI build job script
+#
+# SPDX-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+################################################################################
+# Executed in the 'build' stage.
+################################################################################
+
+# Destructive to the checkout (reconfigures and rebuilds); never run locally
+if [ "$GITHUB_ACTIONS" != "true" ]; then
+  echo "ERROR: $(basename "$0") must only be run in GitHub Actions CI" >&2
+  exit 1
+fi
+
+set -e
+set -x
+
+source "$(dirname "$0")/ci-common.bash"
+
+################################################################################
+# Parse arguments
+
+OPT_ASAN=0
+OPT_CCWARN=0
+OPT_GCOV=0
+OPT_LIGHT_DEBUG=0
+OPT_COMPILER=
+OPT_PREFIX=
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --asan) OPT_ASAN=1 ;;
+    --ccwarn) OPT_CCWARN=1 ;;
+    --compiler)
+      [ $# -ge 2 ] || fatal "--compiler requires an argument"
+      OPT_COMPILER="$2"
+      shift
+      ;;
+    --gcov) OPT_GCOV=1 ;;
+    --light-debug) OPT_LIGHT_DEBUG=1 ;;
+    --prefix)
+      [ $# -ge 2 ] || fatal "--prefix requires an argument"
+      OPT_PREFIX="$2"
+      shift
+      ;;
+    *) fatal "Unknown option: '$1'" ;;
+  esac
+  shift
+done
+
+[ -n "$OPT_COMPILER" ] || fatal "--compiler is required"
+[ -n "$OPT_PREFIX" ] || fatal "--prefix is required"
+
+# Map the compiler name to the executable name configure CXX expects
+case "$OPT_COMPILER" in
+  clang) CXX=clang++ ;;
+  gcc) CXX=g++ ;;
+  *) fatal "Unknown compiler: '$OPT_COMPILER'" ;;
+esac
+
+################################################################################
+# Configure
+
+CONFIGURE_ARGS="--prefix=$OPT_PREFIX --enable-longtests"
+if [ "$OPT_CCWARN" = 1 ]; then
+  CONFIGURE_ARGS="$CONFIGURE_ARGS --enable-ccwarn"
+fi
+if [ "$OPT_ASAN" = 1 ]; then
+  CONFIGURE_ARGS="$CONFIGURE_ARGS --enable-dev-asan"
+  CXX="$CXX -DVL_LEAK_CHECKS"
+fi
+if [ "$OPT_GCOV" = 1 ]; then
+  CONFIGURE_ARGS="$CONFIGURE_ARGS --enable-dev-gcov"
+fi
+if [ "$OPT_LIGHT_DEBUG" = 1 ]; then
+  CONFIGURE_ARGS="$CONFIGURE_ARGS --enable-light-debug"
+fi
+autoconf
+./configure $CONFIGURE_ARGS CXX="$CXX"
+
+################################################################################
+# Build
+
+ccache -z
+BUILD_START=$SECONDS
+"$MAKE" -j "$NPROC" -k
+ccache -svv
+ccache --evict-older-than "$((SECONDS - BUILD_START + 60))s"
+ccache -svv

ci/ci-common.bash

@@ -0,0 +1,35 @@
+# DESCRIPTION: Verilator: CI common definitions, sourced by the stage scripts
+#
+# SPDX-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+################################################################################
+# Common definitions sourced by the CI stage scripts; not executed directly.
+################################################################################
+
+fatal() {
+  echo "ERROR: $(basename "$0"): $1" >&2; exit 1;
+}
+
+case "$(uname -s)" in
+  Linux)
+    HOST_OS=linux
+    MAKE=make
+    NPROC=$(nproc)
+    # Distro id/version; subshell keeps os-release out of our namespace
+    if [ -r /etc/os-release ]; then
+      DISTRO_ID=$(. /etc/os-release; echo "$ID")
+      DISTRO_VERSION=$(. /etc/os-release; echo "$VERSION_ID")
+    fi
+    ;;
+  Darwin)
+    HOST_OS=macOS
+    MAKE=make
+    NPROC=$(sysctl -n hw.logicalcpu)
+    ;;
+  *)
+    fatal "Unknown host OS: '$(uname -s)'"
+    ;;
+esac
+
+export MAKE

ci/ci-install.bash

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 # DESCRIPTION: Verilator: CI dependency install script
 #
-# SPDX-FileCopyrightText: 2020 Geza Lore
+# SPDX-FileCopyrightText: 2026 Wilson Snyder
 # SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
 
 ################################################################################
@@ -10,141 +10,168 @@
 # required by the particular build stage.
 ################################################################################
 
+# Installs system packages with sudo; never run locally
+if [ "$GITHUB_ACTIONS" != "true" ]; then
+  echo "ERROR: $(basename "$0") must only be run in GitHub Actions CI" >&2
+  exit 1
+fi
+
 set -e
 set -x
 
 cd $(dirname "$0")/..
 
+source "$(dirname "$0")/ci-common.bash"
+
+################################################################################
+# Parse arguments
+
+# Which stage to install dependencies for: 'build' or 'test'
+STAGE="$1"
+
+################################################################################
+# Install dependencies
+
 # Avoid occasional cpan failures "Issued certificate has expired."
 export PERL_LWP_SSL_VERIFY_HOSTNAME=0
 echo "check_certificate = off" >> ~/.wgetrc
 
-fatal() {
-  echo "ERROR: $(basename "$0"): $1" >&2; exit 1;
-}
-
-if [ "$CI_OS_NAME" = "linux" ]; then
-  MAKE=make
-elif [ "$CI_OS_NAME" = "osx" ]; then
-  MAKE=make
-elif [ "$CI_OS_NAME" = "freebsd" ]; then
-  MAKE=gmake
-else
-  fatal "Unknown CI_OS_NAME: '$CI_OS_NAME'"
-fi
-
-if [ "$CI_OS_NAME" = "linux" ]; then
+if [ "$HOST_OS" = "linux" ]; then
   # Avoid slow "processing triggers for man db"
   echo "path-exclude /usr/share/doc/*"  | sudo tee -a /etc/dpkg/dpkg.cfg.d/01_nodoc
   echo "path-exclude /usr/share/man/*"  | sudo tee -a /etc/dpkg/dpkg.cfg.d/01_nodoc
   echo "path-exclude /usr/share/info/*" | sudo tee -a /etc/dpkg/dpkg.cfg.d/01_nodoc
+elif [ "$HOST_OS" = "macOS" ]; then
+  # The macos runner image ships an untrusted third-party tap we don't use;
+  # untap it so brew stops emitting a tap-trust warning. Force + '|| true' since
+  # untap fails if a formula was installed from it, which is harmless here.
+  brew untap --force aws/tap || true
 fi
 
 install-wavediff() {
   source ci/docker/buildenv/wavetools.conf
   local _base_url="https://github.com/hudson-trading/wavetools/releases/download/${WAVETOOLS_VERSION}"
   local _platform
-  if [ "$CI_OS_NAME" = "linux" ]; then
+  if [ "$HOST_OS" = "linux" ]; then
     _platform="linux-x86_64"
-  elif [ "$CI_OS_NAME" = "osx" ]; then
+  elif [ "$HOST_OS" = "macOS" ]; then
     _platform="macos-arm64"
-  elif [ "$CI_OS_NAME" = "windows" ]; then
-    _platform="windows-x86_64"
   else
-    echo "WARNING: No wavetools binary available for CI_OS_NAME=$CI_OS_NAME, skipping"
+    echo "WARNING: No wavetools binary available for HOST_OS=$HOST_OS, skipping"
     return 0
   fi
   local _tmpdir
   _tmpdir=$(mktemp -d)
   local _archive="wavetools-${WAVETOOLS_VERSION}-${_platform}"
-  if [ "$CI_OS_NAME" = "windows" ]; then
-    wget -q -O "${_tmpdir}/${_archive}.zip" "${_base_url}/${_archive}.zip"
-    unzip -o "${_tmpdir}/${_archive}.zip" -d "${_tmpdir}"
-  else
-    wget -q -O "${_tmpdir}/${_archive}.tar.gz" "${_base_url}/${_archive}.tar.gz"
-    tar -xzf "${_tmpdir}/${_archive}.tar.gz" -C "${_tmpdir}"
-  fi
+  wget -q -O "${_tmpdir}/${_archive}.tar.gz" "${_base_url}/${_archive}.tar.gz"
+  tar -xzf "${_tmpdir}/${_archive}.tar.gz" -C "${_tmpdir}"
   sudo cp "${_tmpdir}/${_archive}/wavediff" /usr/local/bin/wavediff
   rm -rf "${_tmpdir}"
 }
 
-if [ "$CI_BUILD_STAGE_NAME" = "build" ]; then
+if [ "$STAGE" = "build" ]; then
   ##############################################################################
   # Dependencies of jobs in the 'build' stage, i.e.: packages required to
   # build Verilator
 
-  if [ "$CI_OS_NAME" = "linux" ]; then
-    sudo apt-get update ||
-    sudo apt-get update
-    sudo apt-get install --yes ccache help2man libfl-dev ||
-    sudo apt-get install --yes ccache help2man libfl-dev
-    if [[ ! "$CI_RUNS_ON" =~ "ubuntu-22.04" ]]; then
-      # Some conflict of libunwind verison on 22.04, can live without it for now
-      sudo apt-get install --yes libjemalloc-dev ||
-      sudo apt-get install --yes libjemalloc-dev
-    fi
-    if [[ "$CI_RUNS_ON" =~ "ubuntu-22.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-24.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-26.04" ]]; then
-      if [[ ! "$CI_RUNS_ON" =~ "-riscv" ]]; then
-        sudo apt-get install --yes libsystemc libsystemc-dev ||
-        sudo apt-get install --yes libsystemc libsystemc-dev
+  if [ "$HOST_OS" = "linux" ]; then
+    if [ "$DISTRO_ID" = "ubuntu" ]; then
+      PACKAGES=(
+        bear
+        ccache
+        help2man
+        libfl-dev
+        libsystemc-dev
+        mold
+      )
+      # libunwind conflict on 22.04, can live without libjemalloc there
+      if [ "$DISTRO_VERSION" != "22.04" ]; then
+        PACKAGES+=(libjemalloc-dev)
       fi
+      sudo apt-get update ||
+      sudo apt-get update
+      sudo apt-get install --yes "${PACKAGES[@]}" ||
+      sudo apt-get install --yes "${PACKAGES[@]}"
     fi
-    if [[ "$CI_RUNS_ON" =~ "ubuntu-22.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-24.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-26.04" ]]; then
-      sudo apt-get install --yes bear mold ||
-      sudo apt-get install --yes bear mold
-    fi
-  elif [ "$CI_OS_NAME" = "osx" ]; then
+  elif [ "$HOST_OS" = "macOS" ]; then
+    PACKAGES=(
+      autoconf
+      bison
+      ccache
+      flex
+      gperftools
+      help2man
+      perl
+    )
     brew update ||
     brew update
-    brew install ccache perl gperftools autoconf bison flex help2man ||
-    brew install ccache perl gperftools autoconf bison flex help2man
-  elif [ "$CI_OS_NAME" = "freebsd" ]; then
-    sudo pkg install -y autoconf bison ccache gmake perl5
+    brew install "${PACKAGES[@]}" ||
+    brew install "${PACKAGES[@]}"
   else
-    fatal "Unknown CI_OS_NAME: '$CI_OS_NAME'"
+    fatal "Unknown HOST_OS: '$HOST_OS'"
   fi
-
-  if [ -n "$CCACHE_DIR" ]; then
-    mkdir -p "$CCACHE_DIR"
-  fi
-elif [ "$CI_BUILD_STAGE_NAME" = "test" ]; then
+elif [ "$STAGE" = "test" ]; then
   ##############################################################################
   # Dependencies of jobs in the 'test' stage, i.e.: packages required to
   # run the tests
 
-  if [ "$CI_OS_NAME" = "linux" ]; then
-    sudo apt-get update ||
-    sudo apt-get update
-    # libfl-dev needed for internal coverage's test runs
-    sudo apt-get install --yes gdb gtkwave lcov libfl-dev ccache jq z3 ||
-    sudo apt-get install --yes gdb gtkwave lcov libfl-dev ccache jq z3
-    # Required for test_regress/t/t_dist_attributes.py
-    if [[ "$CI_RUNS_ON" =~ "ubuntu-22.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-24.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-26.04" ]]; then
-      sudo apt-get install --yes python3-clang mold ||
-      sudo apt-get install --yes python3-clang mold
+  if [ "$HOST_OS" = "linux" ]; then
+    if [ "$DISTRO_ID" = "ubuntu" ]; then
+      PACKAGES=(
+        ccache
+        gdb
+        jq
+        lcov
+        libfl-dev
+        libsystemc-dev
+        mold
+        python3-clang
+        z3
+      )
+      sudo apt-get update ||
+      sudo apt-get update
+      sudo apt-get install --yes "${PACKAGES[@]}" ||
+      sudo apt-get install --yes "${PACKAGES[@]}"
     fi
-    if [[ "$CI_RUNS_ON" =~ "ubuntu-22.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-24.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-26.04" ]]; then
-      if [[ ! "$CI_RUNS_ON" =~ "-riscv" ]]; then
-        sudo apt-get install --yes libsystemc libsystemc-dev ||
-        sudo apt-get install --yes libsystemc libsystemc-dev
-      fi
-    fi
-  elif [ "$CI_OS_NAME" = "osx" ]; then
+  elif [ "$HOST_OS" = "macOS" ]; then
+    PACKAGES=(
+      ccache
+      jq
+      perl
+      z3
+    )
+    brew update ||
     brew update
-    # brew cask install gtkwave # fst2vcd hangs at launch, so don't bother
-    brew install ccache perl jq z3
-  elif [ "$CI_OS_NAME" = "freebsd" ]; then
-    # fst2vcd fails with "Could not open '<input file>', exiting."
-    sudo pkg install -y ccache gmake perl5 python3 jq z3
+    brew install "${PACKAGES[@]}" ||
+    brew install "${PACKAGES[@]}"
   else
-    fatal "Unknown CI_OS_NAME: '$CI_OS_NAME'"
+    fatal "Unknown HOST_OS: '$HOST_OS'"
   fi
   # Common installs
   install-wavediff
   # Workaround -fsanitize=address crash
   sudo sysctl -w vm.mmap_rnd_bits=28
+elif [ "$STAGE" = "lint-py" ]; then
+  # nodist/clang_check_attributes.
+  if [ "$HOST_OS" = "linux" ] && [ "$DISTRO_ID" = "ubuntu" ]; then
+    PACKAGES=(
+      python3-clang  # Not run, but importers are linted
+    )
+    sudo apt-get update ||
+    sudo apt-get update
+    sudo apt-get install --yes "${PACKAGES[@]}" ||
+    sudo apt-get install --yes "${PACKAGES[@]}"
+  fi
 else
   ##############################################################################
   # Unknown build stage
-  fatal "Unknown CI_BUILD_STAGE_NAME: '$CI_BUILD_STAGE_NAME'"
+  fatal "Unknown stage '$STAGE' (expected 'build', 'test' or 'lint-py')"
 fi
+
+# Report where the tools we may have installed live (ok if some are missing)
+set +x
+echo "Tools:"
+for bin in autoconf bear bison ccache flex gdb help2man jq lcov mold perl wavediff z3; do
+  echo -n "  $bin: "
+  which "$bin" || echo "Not found"
+done

ci/ci-pages-notify.bash

@@ -34,9 +34,14 @@ for RUN_ID in ${PR_RUN_IDS//,/ }; do
   cat ${ARTIFACTS_DIR}/body.txt
   gh pr comment $(cat ${ARTIFACTS_DIR}/pr-number.txt) --body-file ${ARTIFACTS_DIR}/body.txt
 
-  # Get the artifact ID
-  ARTIFACT_ID=$(gh api "repos/{owner}/{repo}/actions/runs/${RUN_ID}/artifacts" --jq '.artifacts[] | select(.name == "pr-notification") | .id')
+  # Get the artifact IDs. Note there can be more than one artifact named
+  # 'pr-notification' for a single run, as the artifacts endpoint lists
+  # artifacts across all run attempts, and a re-run uploads a new one while
+  # keeping the previous attempt's artifact.
+  ARTIFACT_IDS=$(gh api "repos/{owner}/{repo}/actions/runs/${RUN_ID}/artifacts" --jq '.artifacts[] | select(.name == "pr-notification") | .id')
 
-  # Delete it, so we only notify once
-  gh api --method DELETE "repos/{owner}/{repo}/actions/artifacts/${ARTIFACT_ID}"
+  # Delete them all, so we only notify once
+  for ARTIFACT_ID in ${ARTIFACT_IDS}; do
+    gh api --method DELETE "repos/{owner}/{repo}/actions/artifacts/${ARTIFACT_ID}"
+  done
 done

ci/ci-script.bash

@@ -1,208 +0,0 @@
-#!/usr/bin/env bash
-# DESCRIPTION: Verilator: CI main job script
-#
-# SPDX-FileCopyrightText: 2020 Geza Lore
-# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
-
-################################################################################
-# This is the main script executed in the 'script' phase by all jobs. We use a
-# single script to keep the CI setting simple. We pass job parameters via
-# environment variables using 'env' keys.
-################################################################################
-
-set -e
-set -x
-
-fatal() {
-  echo "ERROR: $(basename "$0"): $1" >&2; exit 1;
-}
-
-if [ "$CI_OS_NAME" = "linux" ]; then
-  export MAKE=make
-  NPROC=$(nproc)
-elif [ "$CI_OS_NAME" = "osx" ]; then
-  export MAKE=make
-  NPROC=$(sysctl -n hw.logicalcpu)
-  # Disable ccache, doesn't always work in GitHub Actions
-  export OBJCACHE=
-elif [ "$CI_OS_NAME" = "freebsd" ]; then
-  export MAKE=gmake
-  NPROC=$(sysctl -n hw.ncpu)
-else
-  fatal "Unknown CI_OS_NAME: '$CI_OS_NAME'"
-fi
-NPROC=$(expr $NPROC '+' 1)
-
-if [ "$CI_BUILD_STAGE_NAME" = "build" ]; then
-  ##############################################################################
-  # Build verilator
-
-  autoconf
-  CONFIGURE_ARGS="--enable-longtests --enable-ccwarn"
-  if [ "$CI_DEV_ASAN" = 1 ]; then
-    CONFIGURE_ARGS="$CONFIGURE_ARGS --enable-dev-asan"
-    CXX="$CXX -DVL_LEAK_CHECKS"
-  fi
-  if [ "$CI_DEV_GCOV" = 1 ]; then
-    CONFIGURE_ARGS="$CONFIGURE_ARGS --enable-dev-gcov"
-  fi
-  ./configure $CONFIGURE_ARGS --prefix="$INSTALL_DIR"
-  ccache -z
-  "$MAKE" -j "$NPROC" -k
-  # 22.04: ccache -s -v
-  ccache -s
-  if [ "$CI_OS_NAME" = "osx" ]; then
-    file bin/verilator_bin
-    file bin/verilator_bin_dbg
-    md5 bin/verilator_bin
-    md5 bin/verilator_bin_dbg
-    stat bin/verilator_bin
-    stat bin/verilator_bin_dbg
-  fi
-elif [ "$CI_BUILD_STAGE_NAME" = "test" ]; then
-  ##############################################################################
-  # Run tests
-
-  export VERILATOR_TEST_NO_CONTRIBUTORS=1  # Separate workflow check
-  export VERILATOR_TEST_NO_LINT_PY=1  # Separate workflow check
-
-  if [ "$CI_OS_NAME" = "osx" ]; then
-    export VERILATOR_TEST_NO_GDB=1  # Pain to get GDB to work on OS X
-    # TODO below may no longer be required as configure checks for -pg
-    export VERILATOR_TEST_NO_GPROF=1  # Apple Clang has no -pg
-    # export PATH="/Applications/gtkwave.app/Contents/Resources/bin:$PATH" # fst2vcd
-    file bin/verilator_bin
-    file bin/verilator_bin_dbg
-    md5 bin/verilator_bin
-    md5 bin/verilator_bin_dbg
-    stat bin/verilator_bin
-    stat bin/verilator_bin_dbg
-    # For some reason, the dbg exe is corrupted by this point ('file' reports
-    # it as data rather than a Mach-O). Unclear if this is an OS X issue or
-    # CI's. Remove the file and re-link...
-    rm bin/verilator_bin_dbg
-    "$MAKE" -j "$NPROC" -k
-  elif [ "$CI_OS_NAME" = "freebsd" ]; then
-    export VERILATOR_TEST_NO_GDB=1 # Disable for now, ideally should run
-    # TODO below may no longer be required as configure checks for -pg
-    export VERILATOR_TEST_NO_GPROF=1 # gprof is a bit different on FreeBSD, disable
-  fi
-
-  TEST_REGRESS=test_regress
-  if [ "$CI_RELOC" == 1 ]; then
-    # Testing that the installation is relocatable.
-    "$MAKE" install
-    mkdir -p "$RELOC_DIR"
-    mv "$INSTALL_DIR" "$RELOC_DIR/relocated-install"
-    export VERILATOR_ROOT="$RELOC_DIR/relocated-install/share/verilator"
-    TEST_REGRESS="$RELOC_DIR/test_regress"
-    mv test_regress "$TEST_REGRESS"
-    NODIST="$RELOC_DIR/nodist"
-    mv nodist "$NODIST"
-    # Feeling brave?
-    find . -delete
-    ls -la .
-  fi
-
-  # Run the specified test
-  ccache -z
-  case $TESTS in
-    dist-vlt-0)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=0/4
-      ;;
-    dist-vlt-1)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=1/4
-      ;;
-    dist-vlt-2)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=2/4
-      ;;
-    dist-vlt-3)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=3/4
-      ;;
-    vltmt-0)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=0/3
-      ;;
-    vltmt-1)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=1/3
-      ;;
-    vltmt-2)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=2/3
-      ;;
-    coverage-dist)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist"
-      ;;
-    coverage-vlt-0)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=0/10
-      ;;
-    coverage-vlt-1)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=1/10
-      ;;
-    coverage-vlt-2)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=2/10
-      ;;
-    coverage-vlt-3)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=3/10
-      ;;
-    coverage-vlt-4)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=4/10
-      ;;
-    coverage-vlt-5)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=5/10
-      ;;
-    coverage-vlt-6)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=6/10
-      ;;
-    coverage-vlt-7)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=7/10
-      ;;
-    coverage-vlt-8)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=8/10
-      ;;
-    coverage-vlt-9)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=9/10
-      ;;
-    coverage-vltmt-0)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=0/10
-      ;;
-    coverage-vltmt-1)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=1/10
-      ;;
-    coverage-vltmt-2)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=2/10
-      ;;
-    coverage-vltmt-3)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=3/10
-      ;;
-    coverage-vltmt-4)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=4/10
-      ;;
-    coverage-vltmt-5)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=5/10
-      ;;
-    coverage-vltmt-6)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=6/10
-      ;;
-    coverage-vltmt-7)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=7/10
-      ;;
-    coverage-vltmt-8)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=8/10
-      ;;
-    coverage-vltmt-9)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=9/10
-      ;;
-    *)
-      fatal "Unknown TESTS: $TESTS"
-      ;;
-  esac
-
-  # To see load average (1 minute, 5 minute, 15 minute)
-  uptime
-  # 22.04: ccache -s -v
-  ccache -s
-
-else
-  ##############################################################################
-  # Unknown build stage
-  fatal "Unknown CI_BUILD_STAGE_NAME: '$CI_BUILD_STAGE_NAME'"
-fi

ci/ci-test.bash

@@ -0,0 +1,169 @@
+#!/usr/bin/env bash
+# DESCRIPTION: Verilator: CI test job script
+#
+# SPDX-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+################################################################################
+# Executed in the 'test' stage.
+################################################################################
+
+# Destructive to the checkout (wipes most of it); never run locally
+if [ "$GITHUB_ACTIONS" != "true" ]; then
+  echo "ERROR: $(basename "$0") must only be run in GitHub Actions CI" >&2
+  exit 1
+fi
+
+set -e
+set -x
+
+source "$(dirname "$0")/ci-common.bash"
+
+################################################################################
+# Parse arguments
+
+OPT_RELOC=
+OPT_SUITE=
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --reloc)
+      [ $# -ge 2 ] || fatal "--reloc requires an argument"
+      OPT_RELOC="$2"
+      shift
+      ;;
+    --suite)
+      [ $# -ge 2 ] || fatal "--suite requires an argument"
+      OPT_SUITE="$2"
+      shift
+      ;;
+    *) fatal "Unknown option: '$1'" ;;
+  esac
+  shift
+done
+
+[ -n "$OPT_SUITE" ] || fatal "--suite is required"
+
+################################################################################
+# Run tests
+
+export VERILATOR_TEST_NO_CONTRIBUTORS=1  # Separate workflow check
+export VERILATOR_TEST_NO_LINT_PY=1  # Separate workflow check
+
+if [ "$HOST_OS" = "macOS" ]; then
+  export VERILATOR_TEST_NO_GDB=1  # No working GDB on macOS
+fi
+
+TEST_REGRESS=test_regress
+if [ -n "$OPT_RELOC" ]; then
+  # Testing that the installation is relocatable.
+  "$MAKE" install
+  # Install prefix, as configured into the Makefile at build time
+  INSTALL_DIR=$(sed -n 's/^prefix = //p' Makefile)
+  mkdir -p "$OPT_RELOC"
+  mv "$INSTALL_DIR" "$OPT_RELOC/relocated-install"
+  export VERILATOR_ROOT="$OPT_RELOC/relocated-install/share/verilator"
+  TEST_REGRESS="$OPT_RELOC/test_regress"
+  mv test_regress "$TEST_REGRESS"
+  NODIST="$OPT_RELOC/nodist"
+  mv nodist "$NODIST"
+  # Delete everything else, but keep the CI infrastructure
+  find . -mindepth 1 -maxdepth 1 ! -name .github ! -name ci -exec rm -rf {} +
+  ls -la .
+fi
+
+# Run the specified suite
+ccache -z
+TEST_START=$SECONDS
+case $OPT_SUITE in
+  dist-vlt-0)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=0/4
+    ;;
+  dist-vlt-1)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=1/4
+    ;;
+  dist-vlt-2)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=2/4
+    ;;
+  dist-vlt-3)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=3/4
+    ;;
+  vltmt-0)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=0/3
+    ;;
+  vltmt-1)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=1/3
+    ;;
+  vltmt-2)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=2/3
+    ;;
+  coverage-dist)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist"
+    ;;
+  coverage-vlt-0)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=0/10
+    ;;
+  coverage-vlt-1)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=1/10
+    ;;
+  coverage-vlt-2)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=2/10
+    ;;
+  coverage-vlt-3)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=3/10
+    ;;
+  coverage-vlt-4)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=4/10
+    ;;
+  coverage-vlt-5)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=5/10
+    ;;
+  coverage-vlt-6)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=6/10
+    ;;
+  coverage-vlt-7)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=7/10
+    ;;
+  coverage-vlt-8)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=8/10
+    ;;
+  coverage-vlt-9)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=9/10
+    ;;
+  coverage-vltmt-0)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=0/10
+    ;;
+  coverage-vltmt-1)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=1/10
+    ;;
+  coverage-vltmt-2)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=2/10
+    ;;
+  coverage-vltmt-3)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=3/10
+    ;;
+  coverage-vltmt-4)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=4/10
+    ;;
+  coverage-vltmt-5)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=5/10
+    ;;
+  coverage-vltmt-6)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=6/10
+    ;;
+  coverage-vltmt-7)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=7/10
+    ;;
+  coverage-vltmt-8)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=8/10
+    ;;
+  coverage-vltmt-9)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=9/10
+    ;;
+  *)
+    fatal "Unknown suite: $OPT_SUITE"
+    ;;
+esac
+ccache -svv
+ccache --evict-older-than "$((SECONDS - TEST_START + 60))s"
+ccache -svv
+uptime # To see load average

ci/ci-win-compile.ps1

@@ -6,19 +6,33 @@
 
 Set-PSDebug -Trace 1
 
-if (-Not (Test-Path $PWD/../.ccache/win_bison.exe)) {
+$NPROC = $env:NUMBER_OF_PROCESSORS
+
+# Absolute path for the win_flex_bison install; CMake reads this from the environment
+$env:WIN_FLEX_BISON = "$(Resolve-Path ..)/win_flex_bison"
+
+if (-Not (Test-Path $env:WIN_FLEX_BISON/win_bison.exe)) {
     git clone --depth 1 https://github.com/lexxmark/winflexbison
     cd winflexbison
     mkdir build
     cd build
-    cmake .. --install-prefix $PWD/../../../.ccache
-    cmake --build . --config Release -j 3
-    cmake --install . --prefix $PWD/../../../.ccache
+    cmake .. --install-prefix $env:WIN_FLEX_BISON
+    cmake --build . --config Release -j $NPROC
+    cmake --install . --prefix $env:WIN_FLEX_BISON
     cd ../..
 }
 
+# Enter the MSVC developer shell so cl/link are on PATH for the Ninja generator
+$VsPath = & "${env:ProgramFiles(x86)}/Microsoft Visual Studio/Installer/vswhere.exe" -latest -products * -property installationPath
+Import-Module "$VsPath/Common7/Tools/Microsoft.VisualStudio.DevShell.dll"
+Enter-VsDevShell -VsInstallPath $VsPath -SkipAutomaticLocation -DevCmdArguments "-arch=x64 -host_arch=x64"
+
 mkdir build
 cd build
-cmake .. --install-prefix $PWD/../install
-cmake --build . --config Release -j 3
+# Ninja saturates all cores; the MSBuild generator only parallelizes across
+# projects and Verilator is a single target, so it compiles serially. /Od skips
+# optimization: this job only checks that Verilator builds and can verilate an
+# example, so an optimized binary is not needed and the codegen time dominates.
+cmake .. -G Ninja -DCMAKE_BUILD_TYPE=Release --install-prefix $PWD/../install "-DCMAKE_CXX_FLAGS_RELEASE=/Od /DNDEBUG"
+cmake --build .
 cmake --install . --prefix $PWD/../install

ci/ci-win-test.ps1

@@ -7,13 +7,17 @@
 
 Set-PSDebug -Trace 1
 
+$NPROC = $env:NUMBER_OF_PROCESSORS
+
 cd install
 $Env:VERILATOR_ROOT=$PWD
 cd examples/cmake_tracing_c
 mkdir build
 cd build
-cmake ..
-cmake --build . --config Release -j 3
+# /Od skips optimization; this only checks the example verilates and builds, so
+# an optimized binary is not needed (see ci-win-compile.ps1).
+cmake .. "-DCMAKE_CXX_FLAGS_RELEASE=/Od /DNDEBUG"
+cmake --build . --config Release -j $NPROC
 
 # TODO put this back in, see issue# 5163
 # Release/example.exe

configure.ac

@@ -12,7 +12,7 @@
 # Then 'make maintainer-dist'
 #AC_INIT([Verilator],[#.### YYYY-MM-DD])
 #AC_INIT([Verilator],[#.### devel])
-AC_INIT([Verilator],[5.050 2026-07-01],
+AC_INIT([Verilator],[5.051 devel],
         [https://verilator.org],
         [verilator],[https://verilator.org])
 
@@ -129,6 +129,21 @@ AC_ARG_ENABLE([dev-gcov],
 AC_SUBST(CFG_WITH_DEV_GCOV)
 AC_MSG_RESULT($CFG_WITH_DEV_GCOV)
 
+# Flag to reduce the debug info in the debug executable to minimize its size
+AC_MSG_CHECKING(whether to reduce debug info in the debug executable)
+AC_ARG_ENABLE([light-debug],
+              [AS_HELP_STRING([--enable-light-debug],
+                              [Reduce the amount of debug information in the debug
+                               Verilator executable to minimize its size. Enable
+                               slight optimization. Enough for backtraces only.])],
+              [case "${enableval}" in
+                yes) CFG_WITH_LIGHT_DEBUG=yes ;;
+                no)  CFG_WITH_LIGHT_DEBUG=no ;;
+                *)   AC_MSG_ERROR([bad value '${enableval}' for --enable-light-debug]) ;;
+               esac],
+               CFG_WITH_LIGHT_DEBUG=no)
+AC_MSG_RESULT($CFG_WITH_LIGHT_DEBUG)
+
 # Special Substitutions - CFG_WITH_DEFENV
 AC_MSG_CHECKING(whether to use hardcoded paths)
 AC_ARG_ENABLE([defenv],
@@ -492,6 +507,11 @@ _MY_CXX_CHECK_CORO_SET(CFG_CXXFLAGS_COROUTINES,-std=gnu++20)
 AC_SUBST(CFG_CXXFLAGS_COROUTINES)
 AC_SUBST(HAVE_COROUTINES)
 
+# Check if the C++ compiler supports ThreadSanitizer
+_MY_CXX_CHECK_IFELSE(-fsanitize=thread,
+  [AC_DEFINE([HAVE_TSAN],[1],[Defined if ThreadSanitizer is supported by $CXX])])
+AC_SUBST(HAVE_TSAN)
+
 # Flags for compiling Verilator internals including parser always
 if test "$CFG_WITH_DEV_ASAN" = "yes"; then
   _MY_CXX_CHECK_IFELSE(-fsanitize=address -DVL_ASAN,
@@ -518,15 +538,27 @@ _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_PARSER,-Wno-unused)
 AC_SUBST(CFG_CXXFLAGS_PARSER)
 
 # Flags for compiling the debug version of Verilator (in addition to above CFG_CXXFLAGS_SRC)
-if test "$CFG_WITH_DEV_GCOV" = "no"; then # Do not optimize for the coverage build
-_MY_CXX_CHECK_OPT(CFG_CXXFLAGS_DBG,-Og)
+if test "$CFG_WITH_LIGHT_DEBUG" = "yes"; then
+  # Slight optimization and minimal compressed debug info. This is enough for
+  # --gdb/--gdbbt backtraces, but omits the bulk of the debug info, which
+  # significantly reduces object file sizes. For CI or release builds.
+  if test "$CFG_WITH_DEV_GCOV" = "no"; then # Do not optimize for the coverage build
+    _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_DBG,-Og)
+  fi
+  _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_DBG,-ggdb1)
+  _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_DBG,-fdebug-info-for-profiling) # For fully-qualified names with clang
+  _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_DBG,-gz)
+else
+  # Full debug: no optimization, full debug info, for development.
+  _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_DBG,-O0)
+  _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_DBG,-ggdb)
 fi
-_MY_CXX_CHECK_OPT(CFG_CXXFLAGS_DBG,-ggdb)
-_MY_CXX_CHECK_OPT(CFG_CXXFLAGS_DBG,-gz)
 AC_SUBST(CFG_CXXFLAGS_DBG)
 
 # Flags for linking the debug version of Verilator (in addition to above CFG_LDFLAGS_SRC)
-_MY_LDLIBS_CHECK_OPT(CFG_LDFLAGS_DBG,-gz)
+if test "$CFG_WITH_LIGHT_DEBUG" = "yes"; then
+  _MY_LDLIBS_CHECK_OPT(CFG_LDFLAGS_DBG,-gz)
+fi
 AC_SUBST(CFG_LDFLAGS_DBG)
 
 # Flags for compiling the optimized version of Verilator (in addition to above CFG_CXXFLAGS_SRC)

docs/CONTRIBUTORS

@@ -7,6 +7,7 @@ contribution terms including the AI policy in ``docs/CONTRIBUTING.rst``.
 
 Please see the Verilator manual for 200+ additional contributors. Thanks to all.
 
+24bit-xjkp
 404allen404
 Adam Bagley
 Adam Kostrzewski
@@ -14,6 +15,7 @@ Adrian Sampson
 Adrien Le Masle
 أحمد المحمودي (Ahmed El-Mahmoudy)
 Aidan McNay
+Aisha Salimgereyeva
 Aleksander Kiryk
 Alex Chadwick
 Alex Solomatnikov
@@ -26,16 +28,20 @@ Andrei Kostovski
 Andrew Miloradovsky
 Andrew Nolte
 Andrew Voznytsa
+Andrii Andrieiev
 anonkey
 Anthony Donlon
 Anthony Moore
+apocelipes
 Arkadiusz Kozdra
 Arthur Rosa
 Artur Bieniek
 AUDIY
 Aylon Chaim Porat
+Bartosz Skorowski
 Bartłomiej Chmiel
 Benjamin Collier
+BRDR LIFE
 Brian Li
 Cameron Kirk
 Cameron Waite
@@ -53,27 +59,35 @@ Dan Ruelas-Petrisko
 Daniel Bates
 Danny Oler
 Dave Sargeant
+David Garau
 David Horton
 David Ledger
 David Metz
 David Stanford
 David Turner
+dependabot[bot]
 Dercury
+Demin Han
 Diego Roux
 Dominick Grochowina
 Don Williamson
+Dragon-Git
 Drew Ranck
 Drew Taussig
 Driss Hafdi
 Edgar E. Iglesias
+em2machine
+emmettifelts
 Eric Mejdrich
 Eric Müller
 Eric Rippey
-Eunseo Song
+Eryk Szpotański
 Ethan Sifferman
+Eunseo Song
 Eyck Jentzsch
 Fabian Keßler-Schulz
 Fan Shupei
+february cozzocrea
 Felix Neumärker
 Felix Yan
 Frans Skarman
@@ -108,6 +122,8 @@ Ilya Barkov
 Iru Cai
 Ivan Vnučec
 Iztok Jeras
+JAEUK LEE
+Jaeuk Lee (이재욱)
 Jake Merdich
 Jakub Michalski
 Jakub Wasilewski
@@ -122,6 +138,8 @@ Jamie Iles
 Jan Van Winkel
 Jean Berniolles
 Jean-Nicolas Strauss
+Jeffrey Song
+jeffrey.song
 Jens Yuechao Liu
 Jeremy Bennett
 Jesse Taube
@@ -147,6 +165,7 @@ Josep Sans
 Joseph Nwabueze
 Josh Redford
 Joshua Leahy
+JOTEGO (Jose Tejada)
 Julian Carrier
 Julian Daube
 Julie Schwartz
@@ -183,6 +202,7 @@ Maarten De Braekeleer
 Maciej Sobkowski
 Marcel Chang
 Marco Bartoli
+Marco Brambilla
 Marco Widmer
 Mariusz Glebocki
 Markus Krause
@@ -208,6 +228,7 @@ Mladen Slijepcevic
 Morten Borup Petersen
 Mostafa Gamal
 Moubarak Jeje
+Muzaffer Kal
 Nandu Raj
 Natan Kreimer
 Nathan Graybeal
@@ -218,8 +239,10 @@ Nikolai Kumar
 Nikolay Puzanov
 Nolan Poe
 Oleh Maksymenko
+Patrick Creighton
 Patrick Stewart
 Paul Bowen-Huggett
+Paul Campbell
 Paul Swirhun
 Paul Wright
 Pawel Jewstafjew
@@ -262,15 +285,19 @@ Sergey Chusov
 Sergey Fedorov
 Sergi Granell
 Seth Pellegrino
+Shashvat Prabhu
 Shogo Yamazaki
 Shou-Li Hsu
+spomatasmd
 Srinivasan Venkataramanan
 Stefan Wallentowitz
 Stephen Henry
 Steven Hugg
 Stuart Morris
+sumpster
 Szymon Gizler
 Sören Tempel
+Sumanth Kadiyala
 Teng Huang
 Thomas Aldrian
 Thomas Brown
@@ -291,6 +318,7 @@ Tracy Narine
 Trung Nguyen
 Tudor Timi
 Tymoteusz Blazejczyk
+Tyrone Marhguy
 Udaya Raj Subedi
 Udi Finkelstein
 Unai Martinez-Corral
@@ -308,9 +336,11 @@ Wolfgang Mayerwieser
 Xi Zhang
 Yan Xu
 Yangyu Chen
+Yilin Li
 Yilou Wang
 Yinan Xu
 Yoda Lee
+Yogish Sekhar
 Yossi Nivin
 Yu-Sheng Lin
 Yuri Victorovich
@@ -321,17 +351,7 @@ Zhen Yan
 Zhou Shen
 Zhouyi Shen
 Zixi Li
-apocelipes
-dependabot[bot]
-february cozzocrea
-sumpster
-em2machine
-emmettifelts
+Zubin Jain
 Àlex Torregrosa
 Ícaro Lima
-Yogish Sekhar
-24bit-xjkp
-Zubin Jain
-Muzaffer Kal
-Yilin Li
-Shashvat Prabhu
+Sunimali Rathnayake

docs/gen/ex_MULTIDRIVENPROC_faulty.rst

@@ -0,0 +1,6 @@
+.. comment: generated by t_lint_multidriven_proc_bad
+.. code-block:: sv
+   :linenos:
+
+     always @(posedge clk) q <= d;
+     always @(posedge clk) q <= ~d;

docs/gen/ex_MULTIDRIVENPROC_msg.rst

@@ -0,0 +1,8 @@
+.. comment: generated by t_lint_multidriven_proc_bad
+.. code-block::
+
+   %Warning-MULTIDRIVENPROC: example.v:1:25 Variable written to in always block also written by another always block: 'q'
+                                                                  : ... note: In instance 't'
+                             example.v:1:25
+      16 |   always @(posedge clk) q <= ~d;
+         |                         ^

docs/gen/ex_SIMILARNAME_faulty.rst

@@ -0,0 +1,6 @@
+.. comment: generated by t_lint_similarname_bad
+.. code-block:: sv
+   :linenos:
+
+     reg i;
+     wire I;

docs/gen/ex_SIMILARNAME_msg.rst

@@ -0,0 +1,9 @@
+.. comment: generated by t_lint_similarname_bad
+.. code-block::
+
+   %Warning-SIMILARNAME: example.v:1:8 Declaration overlaps another with different case: 'I'
+      13 |   wire I;
+         |        ^
+                         example.v:1:7 ... Location of original declaration
+      12 |   reg i;
+         |       ^

docs/guide/connecting.rst

@@ -92,13 +92,17 @@ model.
 Refer to ``examples/make_tracing_c`` in the distribution for a detailed
 commented example.
 
-Top level IO signals are read and written as members of the model. You call
-the model's ``eval()`` method to evaluate the model. When the simulation is
-complete call the model's ``final()`` method to execute any SystemVerilog
-final blocks, and complete any assertions. If using :vlopt:`--timing`,
-there are two additional functions for checking if there are any events
-pending in the simulation due to delays, and for retrieving the simulation
-time of the next delayed event. See :ref:`Evaluation Loop`.
+Top level IO signals are read and written as members of the model. All
+inputs must be sanitized, that is have no bits set above those
+corresponding to the width of the Verilog construct;
+:vlopt:`--runtime-debug` will assert this is correct.
+
+Call the model's ``eval()`` method to evaluate the model. When the
+simulation is complete call the model's ``final()`` method to execute any
+SystemVerilog final blocks, and complete any assertions. If using
+:vlopt:`--timing`, there are two additional functions for checking if there
+are any events pending in the simulation due to delays, and for retrieving
+the simulation time of the next delayed event. See :ref:`Evaluation Loop`.
 
 
 Connecting to SystemC
@@ -179,7 +183,7 @@ DPI Example
 In the SYSTEMC example above, if you wanted to import C++ functions into
 Verilog, put in our.v:
 
-.. code-block:: sv
+.. code-block::
 
    import "DPI-C" function int add (input int a, input int b);
 
@@ -211,7 +215,7 @@ Verilator extends the DPI format to allow using the same scheme to
 efficiently add system functions. Use a dollar-sign prefixed system
 function name for the import, but note it must be escaped.
 
-.. code-block:: sv
+.. code-block::
 
    import "DPI-C" function integer \$myRand;
 

docs/guide/exe_sim.rst

@@ -21,6 +21,13 @@ Summary:
 
 Options:
 
+.. option:: +verilator+assert+lock
+
+   Only allow command line options to disable / enable assertions.
+   Disables RTL from changing assertion handling via ``$asserton``,
+   ``$assertoff``, and ``$assertcontrol``. Also prevents ``VerilatedContext*``
+   assertion control functions from updating assertion handling.
+
 .. option:: +verilator+coverage+file+<filename>
 
    When a model was Verilated using :vlopt:`--coverage`, sets the filename
@@ -114,7 +121,7 @@ Options:
    When a model was Verilated using :vlopt:`--x-initial unique
    <--x-initial>`, sets the simulation runtime initialization technique. 0
    = Reset to zeros. 1 = Reset to all-ones. 2 = Randomize. See
-   :ref:`Unknown States`.
+   :ref:`Unknown States`.  Default is 0.
 
 .. option:: +verilator+seed+<value>
 

docs/guide/exe_verilator.rst

@@ -715,6 +715,10 @@ Summary:
 
 .. option:: -fno-dfg-break-cycles
 
+   Deprecated and has no effect (ignored).
+
+   In versions before 5.052:
+
    Rarely needed. Disable breaking combinational cycles during DFG.
 
 .. option:: -fno-dfg-peephole
@@ -936,7 +940,7 @@ Summary:
    :file:`*.mk` files.
 
    Feature may be one of the following: COROUTINES, DEV_ASAN, DEV_GCOV,
-   SYSTEMC.
+   SYSTEMC, TSAN.
 
 .. option:: --getenv <variable>
 

docs/guide/exe_verilator_coverage.rst

@@ -133,7 +133,7 @@ verilator_coverage Arguments
 
 .. option:: --filter-type <regex>
 
-   Skips records of coverage types that matches with <regex>
+   Keeps records of coverage types that matches with <regex>
    Possible values are `toggle`, `line`, `branch`, `expr`, `covergroup`,
    `user`, `fsm_state`, `fsm_arc` and a wildcard with `\*` or `?`. The
    default value is `\*`.

docs/guide/extensions.rst

@@ -294,6 +294,25 @@ or "`ifdef`"'s may break other tools.
    (if appropriate :vlopt:`--coverage` flags are passed) after being
    disabled earlier with :option:`/*verilator&32;coverage_off*/`.
 
+.. option:: /*verilator&32;dpi_c_decl "<C function declaration>"*/
+
+   Specifies C function declaration that will be emitted for given DPI-C
+   function into the Verilator-generated __Dpi.h header, replacing the declaration
+   that Verilator would build by default using the Verilog function signature.
+
+   This enables use of C functions with types not specified in the
+   standard. For example, it enables use of functions that return ``char*``:
+
+   .. code-block:: sv
+
+      module t;
+        import "DPI-C" function string getenv(input string arg) /*verilator dpi_c_decl "char* getenv(const char*)"*/;
+
+        initial begin
+          $display("%s", getenv("HOME"));
+        end
+      endmodule
+
 .. option:: /*verilator&32;fargs <arguments>*/
 
    For Verilator developers only. When a source file containing these `fargs`

docs/guide/simulating.rst

@@ -66,7 +66,7 @@ The information in this report is:
 
 .. describe:: "allocated 123 MB"
 
-   Total memory used during simulation in megabytes.
+   Peak resident memory used during simulation in megabytes.
 
 
 .. _benchmarking & optimization:

docs/guide/verilating.rst

@@ -623,5 +623,5 @@ The information in this report is:
 
 .. describe:: "allocated 123 MB"
 
-   Total memory used during build by Verilator executable (excludes
-   :vlopt:`--build` compiler's usage) in megabytes.
+   Peak resident memory used by the Verilator executable during build
+   (excludes :vlopt:`--build` compiler's usage) in megabytes.

docs/guide/warnings.rst

@@ -1469,11 +1469,50 @@ List Of Warnings
         q <= d;
       end
 
+   A further case is when a signal named as a clocking block ``output`` is
+   also driven by a continuous assignment, or is named as an ``output`` of a
+   second clocking block. The clocking block drives the signal, so the design
+   and the testbench contend for it and the synchronous drive may be silently
+   lost. Declare the clocking block ``input`` if the intent is only to
+   observe the signal.
+
    Ignoring this warning may hide clock domain crossing, timing, or
    portability bugs. It may also cause longer simulation runtimes due to
    reduced optimizations.
 
 
+.. option:: MULTIDRIVENPROC
+
+   Warns that the whole of a variable is driven by more than one plain
+   ``always`` block. Unlike the :option:`MULTIDRIVEN` cases, plain
+   ``always`` blocks carry no ``always_comb``/``always_ff`` intent, so this
+   is legal SystemVerilog rather than an IEEE 1800 violation. It is,
+   however, typically a synthesis error: hardware cannot have a signal
+   driven by two separate sequential blocks, so the design usually will not
+   behave as the RTL simulation suggests.
+
+   Disabled by default as this is a code-style warning; it will simulate
+   correctly.
+
+   Faulty example:
+
+   .. include:: ../../docs/gen/ex_MULTIDRIVENPROC_faulty.rst
+
+   Results in:
+
+   .. include:: ../../docs/gen/ex_MULTIDRIVENPROC_msg.rst
+
+   Also warns when a signal named as a clocking block ``output`` is driven
+   by a plain ``always`` block. Driving a signal from both a clocking block
+   and a plain ``always`` block is a deliberate idiom in some testbenches,
+   so it is reported as MULTIDRIVENPROC rather than under the on-by-default
+   :option:`MULTIDRIVEN`.
+
+   To fix, drive the signal from a single ``always`` block, or use
+   ``always_ff``/``always_comb`` if the intent is a single specialized
+   process.
+
+
 .. option:: MULTITOP
 
    .. TODO better example
@@ -2089,6 +2128,25 @@ List Of Warnings
    simulators.
 
 
+.. option:: SIMILARNAME
+
+   Warns that a variable name only differs from another in lexical case.
+
+   Faulty example:
+
+   .. include:: ../../docs/gen/ex_SIMILARNAME_faulty.rst
+
+   Results in:
+
+   .. include:: ../../docs/gen/ex_SIMILARNAME_msg.rst
+
+   Disabled by default as this is a code-style warning; it will simulate
+   correctly.
+
+   This is a warning as some downstream VLSI tools do
+   not distinguish net and gate names with the same case.
+
+
 .. option:: SPECIFYIGN
 
    Warns that Verilator does not support certain constructs in

docs/spelling.txt

@@ -477,6 +477,7 @@ Syms
 Synopsys
 SystemC
 SystemVerilog
+Szpotanski
 Takatsukasa
 Tambe
 Tarik
@@ -537,6 +538,7 @@ Verilog
 Vighnesh
 Viktor
 Vilp
+VlRNG
 VlWide
 Vlip
 Vm
@@ -644,6 +646,7 @@ casez
 casted
 castro
 cb
+cbValueChange
 ccache
 ccall
 cdc
@@ -707,6 +710,7 @@ de
 dearray
 deassign
 debugi
+deduplication
 defenv
 defname
 defparam
@@ -947,6 +951,7 @@ misconnected
 misconversion
 misdetecting
 misoptimized
+misoptimizing
 missized
 mk
 mno
@@ -1174,6 +1179,7 @@ tcmalloc
 tcmalloc
 tenghtt
 testbench
+testbenches
 threadsafe
 threashold
 timeInc

include/verilated.cpp

@@ -243,20 +243,32 @@ void vl_warn(const char* filename, int linenum, const char* hier, const char* ms
 // Wrapper to call certain functions via messages when multithreaded
 
 void VL_FINISH_MT(const char* filename, int linenum, const char* hier) VL_MT_SAFE {
+    VerilatedContext* const contextp = Verilated::threadContextp();
+    contextp->finishPendingInc();
     VerilatedThreadMsgQueue::post(VerilatedMsg{[=]() {  //
         vl_finish(filename, linenum, hier);
+        contextp->finishPendingDec();
     }});
 }
 
 void VL_STOP_MT(const char* filename, int linenum, const char* hier, bool maybe) VL_MT_SAFE {
+    // Classify now, so a queued request is pending from the moment it is posted
+    VerilatedContext* const contextp = Verilated::threadContextp();
+    const bool stop = contextp->stopRequestReserve(maybe);
+    if (stop) contextp->finishPendingInc();
     VerilatedThreadMsgQueue::post(VerilatedMsg{[=]() {  //
         vl_stop_maybe(filename, linenum, hier, maybe);
+        contextp->stopRequestRelease();
+        if (stop) contextp->finishPendingDec();
     }});
 }
 
 void VL_FATAL_MT(const char* filename, int linenum, const char* hier, const char* msg) VL_MT_SAFE {
+    VerilatedContext* const contextp = Verilated::threadContextp();
+    contextp->finishPendingInc();
     VerilatedThreadMsgQueue::post(VerilatedMsg{[=]() {  //
         vl_fatal(filename, linenum, hier, msg);
+        contextp->finishPendingDec();
     }});
 }
 
@@ -563,9 +575,10 @@ IData VL_URANDOM_SEEDED_II(IData seed) VL_MT_SAFE {
 }
 
 IData VL_SCOPED_RAND_RESET_I(int obits, uint64_t scopeHash, uint64_t salt) VL_MT_UNSAFE {
-    if (Verilated::threadContextp()->randReset() == 0) return 0;
+    const int randReset = Verilated::threadContextp()->randReset();
+    if (randReset == 0) return 0;
     IData data = ~0;
-    if (Verilated::threadContextp()->randReset() != 1) {  // if 2, randomize
+    if (randReset != 1) {  // if 2, randomize
         VlRNG rng{Verilated::threadContextp()->randSeed() ^ scopeHash ^ salt};
         data = rng.rand64();
     }
@@ -574,9 +587,10 @@ IData VL_SCOPED_RAND_RESET_I(int obits, uint64_t scopeHash, uint64_t salt) VL_MT
 }
 
 QData VL_SCOPED_RAND_RESET_Q(int obits, uint64_t scopeHash, uint64_t salt) VL_MT_UNSAFE {
-    if (Verilated::threadContextp()->randReset() == 0) return 0;
+    const int randReset = Verilated::threadContextp()->randReset();
+    if (randReset == 0) return 0;
     QData data = ~0ULL;
-    if (Verilated::threadContextp()->randReset() != 1) {  // if 2, randomize
+    if (randReset != 1) {  // if 2, randomize
         VlRNG rng{Verilated::threadContextp()->randSeed() ^ scopeHash ^ salt};
         data = rng.rand64();
     }
@@ -586,10 +600,17 @@ QData VL_SCOPED_RAND_RESET_Q(int obits, uint64_t scopeHash, uint64_t salt) VL_MT
 
 WDataOutP VL_SCOPED_RAND_RESET_W(int obits, WDataOutP outwp, uint64_t scopeHash,
                                  uint64_t salt) VL_MT_UNSAFE {
-    if (Verilated::threadContextp()->randReset() != 2) { return VL_RAND_RESET_W(obits, outwp); }
-    VlRNG rng{Verilated::threadContextp()->randSeed() ^ scopeHash ^ salt};
-    for (int i = 0; i < VL_WORDS_I(obits) - 1; ++i) outwp[i] = rng.rand64();
-    outwp[VL_WORDS_I(obits) - 1] = rng.rand64() & VL_MASK_E(obits);
+    const int words = VL_WORDS_I(obits);
+    const int randReset = Verilated::threadContextp()->randReset();
+    if (randReset == 0) {
+        VL_MEMSET_ZERO_W(outwp, words);
+    } else if (randReset == 1) {
+        VL_MEMSET_ONES_W(outwp, words);
+    } else {
+        VlRNG rng{Verilated::threadContextp()->randSeed() ^ scopeHash ^ salt};
+        for (int i = 0; i < words; ++i) outwp[i] = rng.rand64();
+    }
+    outwp[words - 1] &= VL_MASK_E(obits);
     return outwp;
 }
 
@@ -614,30 +635,14 @@ WDataOutP VL_SCOPED_RAND_RESET_ASSIGN_W(int obits, WDataOutP outwp, uint64_t sco
 }
 
 IData VL_RAND_RESET_I(int obits) VL_MT_SAFE {
-    if (Verilated::threadContextp()->randReset() == 0) return 0;
+    const int randReset = Verilated::threadContextp()->randReset();
+    if (randReset == 0) return 0;
     IData data = ~0;
-    if (Verilated::threadContextp()->randReset() != 1) {  // if 2, randomize
-        data = VL_RANDOM_I();
-    }
+    if (randReset != 1) data = VL_RANDOM_I();  // if 2, randomize
     data &= VL_MASK_I(obits);
     return data;
 }
 
-QData VL_RAND_RESET_Q(int obits) VL_MT_SAFE {
-    if (Verilated::threadContextp()->randReset() == 0) return 0;
-    QData data = ~0ULL;
-    if (Verilated::threadContextp()->randReset() != 1) {  // if 2, randomize
-        data = VL_RANDOM_Q();
-    }
-    data &= VL_MASK_Q(obits);
-    return data;
-}
-
-WDataOutP VL_RAND_RESET_W(int obits, WDataOutP outwp) VL_MT_SAFE {
-    for (int i = 0; i < VL_WORDS_I(obits) - 1; ++i) outwp[i] = VL_RAND_RESET_I(32);
-    outwp[VL_WORDS_I(obits) - 1] = VL_RAND_RESET_I(32) & VL_MASK_E(obits);
-    return outwp;
-}
 WDataOutP VL_ZERO_RESET_W(int obits, WDataOutP outwp) VL_MT_SAFE {
     // Not inlined to speed up compilation of slowpath code
     return VL_ZERO_W(obits, outwp);
@@ -3087,6 +3092,7 @@ VerilatedContext::Serialized::Serialized() {
 
 bool VerilatedContext::assertOn() const VL_MT_SAFE { return m_s.m_assertOn; }
 void VerilatedContext::assertOn(bool flag) VL_MT_SAFE {
+    if (assertCtlsLocked()) return;
     // Set all assert and directive types when true, clear otherwise.
     m_s.m_assertOn = VL_MASK_I(ASSERT_ON_WIDTH) * flag;
 }
@@ -3105,16 +3111,22 @@ uint32_t VerilatedContext::assertOnMask(VerilatedAssertType_t types,
 }
 void VerilatedContext::assertOnSet(VerilatedAssertType_t types,
                                    VerilatedAssertDirectiveType_t directives) VL_MT_SAFE {
+    if (assertCtlsLocked()) return;
     m_s.m_assertOn |= assertOnMask(types, directives);
 }
 void VerilatedContext::assertOnClear(VerilatedAssertType_t types,
                                      VerilatedAssertDirectiveType_t directives) VL_MT_SAFE {
+    if (assertCtlsLocked()) return;
     m_s.m_assertOn &= ~assertOnMask(types, directives);
 }
+bool VerilatedContext::assertCtlsLocked() const VL_MT_SAFE { return m_ns.m_assertCtlsLocked; }
+void VerilatedContext::assertCtlsLocked(bool flag) VL_MT_SAFE { m_ns.m_assertCtlsLocked = flag; }
 void VerilatedContext::assertCtl(uint32_t controlType, VerilatedAssertType_t types,
                                  VerilatedAssertDirectiveType_t directives) VL_MT_SAFE {
     // IEEE 1800-2023 Table 20-5 control_type. Lock freezes the On/Off state of the
     // selected bits until Unlock; On/Off/Kill leave locked bits unchanged.
+    // +verilator+assert+lock freezes everything, including Lock/Unlock itself.
+    if (assertCtlsLocked()) return;
     const uint32_t mask = assertOnMask(types, directives);
     const uint32_t lockedMask = mask & ~m_s.m_assertLock;
     switch (controlType) {
@@ -3286,6 +3298,15 @@ void VerilatedContext::gotFinish(bool flag) VL_MT_SAFE {
     const VerilatedLockGuard lock{m_mutex};
     m_s.m_gotFinish = flag;
 }
+bool VerilatedContext::stopRequestReserve(bool maybe) VL_MT_SAFE {
+    const VerilatedLockGuard lock{m_mutex};
+    const int reserved = ++m_ns.m_stopReserved;
+    return !maybe || m_s.m_errorCount + reserved >= m_s.m_errorLimit;
+}
+void VerilatedContext::stopRequestRelease() VL_MT_SAFE {
+    const VerilatedLockGuard lock{m_mutex};
+    --m_ns.m_stopReserved;
+}
 bool VerilatedContext::executingFinal() const VL_MT_SAFE {
     const VerilatedLockGuard lock{m_mutex};
     return m_ns.m_executingFinal;
@@ -3556,7 +3577,9 @@ void VerilatedContextImp::commandArgVl(const std::string& arg) {
     if (0 == std::strncmp(arg.c_str(), "+verilator+", std::strlen("+verilator+"))) {
         std::string str;
         uint64_t u64;
-        if (commandArgVlString(arg, "+verilator+coverage+file+", str)) {
+        if (arg == "+verilator+assert+lock") {
+            assertCtlsLocked(true);
+        } else if (commandArgVlString(arg, "+verilator+coverage+file+", str)) {
             coverageFilename(str);
         } else if (arg == "+verilator+debug") {
             Verilated::debug(4);
@@ -3575,7 +3598,8 @@ void VerilatedContextImp::commandArgVl(const std::string& arg) {
             logFilename(str);
             logOutputToFile(false /* append */);
         } else if (arg == "+verilator+noassert") {
-            assertOn(false);
+            // Set directly on to avoid conflicts with +verilator+assert+lock
+            m_s.m_assertOn = 0;
         } else if (commandArgVlUint64(arg, "+verilator+prof+exec+start+", u64)) {
             profExecStart(u64);
         } else if (commandArgVlUint64(arg, "+verilator+prof+exec+window+", u64, 1)) {
@@ -3891,7 +3915,7 @@ void Verilated::runFlushCallbacks() VL_MT_SAFE {
     // When running internal code coverage (gcc --coverage, as opposed to
     // verilator --coverage), dump coverage data to properly cover failing
     // tests.
-    VL_GCOV_DUMP();
+    VL_GCOV_DUMP_RESET();
 }
 
 void Verilated::addExitCb(VoidPCb cb, void* datap) VL_MT_SAFE { addCbExit(cb, datap); }
@@ -4142,6 +4166,50 @@ VerilatedVar* VerilatedScope::varInsert(const char* namep, void* datap, bool isP
     return &(m_varsp->find(namep)->second);
 }
 
+void VerilatedScope::varsInsertFromTable(const VlVarTableEntry* entp, size_t n,
+                                         void* basep) VL_MT_UNSAFE {
+    // Table-driven equivalent of a run of varInsert()/varInsertSized() calls; see VlVarTableEntry.
+    if (!m_varsp) m_varsp = new VerilatedVarNameMap;
+    uint8_t* const base = static_cast<uint8_t*>(basep);
+    for (size_t i = 0; i < n; ++i) {
+        const VlVarTableEntry& e = entp[i];
+        void* const datap = base + e.byteOffset;
+        const VerilatedVarFlags vlflags = static_cast<VerilatedVarFlags>(e.vlflags);
+        VerilatedVar var{e.namep, datap, e.vltype, vlflags, e.udims, e.pdims, /*isParam=*/false};
+        for (int d = 0; d < e.udims; ++d) {
+            var.m_unpacked[d].m_left = e.dims[2 * d];
+            var.m_unpacked[d].m_right = e.dims[2 * d + 1];
+        }
+        for (int d = 0; d < e.pdims; ++d) {
+            var.m_packed[d].m_left = e.dims[2 * (e.udims + d)];
+            var.m_packed[d].m_right = e.dims[2 * (e.udims + d) + 1];
+        }
+        // Recompute the flattened DPI packed range now dims are known (see
+        // VerilatedVarProps::initPacked)
+        if (e.pdims == 1) {
+            var.m_packedDpi = var.m_packed.front();
+        } else if (e.pdims > 1) {
+            int packedSize = 1;
+            for (int d = 0; d < e.pdims; ++d) packedSize *= var.m_packed[d].elements();
+            var.m_packedDpi = VerilatedRange{packedSize - 1, 0};
+        }
+        m_varsp->emplace(e.namep, std::move(var));
+    }
+}
+
+void VerilatedScope::scopesConstructFromTable(const VlScopeTableEntry* entp, size_t n,
+                                              VerilatedSyms* symsp) VL_MT_UNSAFE {
+    // Table-driven equivalent of a run of 'new VerilatedScope{...}' statements; see
+    // VlScopeTableEntry. The generated Syms class derives VerilatedSyms as its sole primary
+    // base at offset 0, so symsp doubles as the base for the offsetof-baked member addresses.
+    uint8_t* const base = reinterpret_cast<uint8_t*>(symsp);
+    for (size_t i = 0; i < n; ++i) {
+        const VlScopeTableEntry& e = entp[i];
+        VerilatedScope** const slotp = reinterpret_cast<VerilatedScope**>(base + e.ptrOffset);
+        *slotp = new VerilatedScope{symsp, e.namep, e.identp, e.defnamep, e.timeunit, e.type};
+    }
+}
+
 VerilatedVar* VerilatedScope::varInsertSized(const char* namep, void* datap, bool isParam,
                                              VerilatedVarType vltype, int vlflags, int udims,
                                              uint32_t entSize...) VL_MT_UNSAFE {

include/verilated.h

@@ -160,6 +160,21 @@ enum VerilatedVarFlags : uint32_t {
     VLVF_NET = (1 << 15)  // Net object
 };
 
+// One VPI-visible variable, consumed by VerilatedScope::varsInsertFromTable();
+// replaces per-variable varInsert() calls, which compiles faster at scale.
+struct VlVarTableEntry final {
+    static constexpr int kMaxDims = 3;  // Max packed+unpacked dims a table row holds
+    const char* namep;  // VPI-facing (protected) variable name, string literal
+    size_t byteOffset;  // offsetof of storage member from module instance base
+    VerilatedVarType vltype;
+    uint32_t vlflags;  // Direction + flags (VLVD_*/VLVF_*)
+    uint8_t udims;  // udims + pdims <= kMaxDims
+    uint8_t pdims;
+    // (left,right) pairs: unpacked dims first, then packed; int32_t since large
+    // unpacked memories exceed int16 range
+    int32_t dims[kMaxDims * 2];
+};
+
 // IEEE 1800-2023 Table 20-6
 enum class VerilatedAssertType : uint8_t {
     ASSERT_TYPE_CONCURRENT = (1 << 0),
@@ -372,6 +387,8 @@ private:
     static uint32_t assertOnMask(VerilatedAssertType_t types,
                                  VerilatedAssertDirectiveType_t directives) VL_PURE;
     static constexpr size_t ASSERT_CONTROL_SLOT_COUNT = ASSERT_ON_WIDTH - 1;
+    // No termination request has stamped m_finishPendingTime yet
+    static constexpr uint64_t TIME_UNSET = ~0ULL;
 
 protected:
     // TYPES
@@ -430,6 +447,12 @@ protected:
     struct NonSerialized final {  // Non-serialized information
         // These are reloaded from on command-line settings, so do not need to persist
         // Fast path
+        // A worker queues $finish before the main thread callback can set m_gotFinish.
+        std::atomic<uint32_t> m_finishPending{0};  // Number of queued $finish callbacks
+        std::atomic<uint64_t> m_finishPendingTime{TIME_UNSET};  // Time of the first callback
+        std::atomic<bool> m_assertCtlsLocked{
+            false};  // When true, all assertion-control updates are ignored
+        int m_stopReserved = 0;  // Posted $stop requests not yet executed
         bool m_executingFinal = false;  // Running generated final() code
         uint64_t m_profExecStart = 1;  // +prof+exec+start time
         uint32_t m_profExecWindow = 2;  // +prof+exec+window size
@@ -510,6 +533,12 @@ public:
     /// Clear enabled status for given assertion types
     void assertOnClear(VerilatedAssertType_t types,
                        VerilatedAssertDirectiveType_t directives) VL_MT_SAFE;
+    /// Return if assertion-control updates are locked. When locked, RTL assert
+    // control statements ($asserton/$assertoff/$assertcontrol) are ignored, as
+    // are updates from the C++ API.
+    bool assertCtlsLocked() const VL_MT_SAFE;
+    /// Lock/unlock assertion-control updates.
+    void assertCtlsLocked(bool flag) VL_MT_SAFE;
     /// Apply assertion control for given control, assertion, and directive types
     void assertCtl(uint32_t controlType, VerilatedAssertType_t types,
                    VerilatedAssertDirectiveType_t directives) VL_MT_SAFE;
@@ -669,6 +698,27 @@ public:
 
     // METHODS - public but for internal use only
 
+    // Internal: Track $finish/$stop callbacks queued by worker threads
+    bool finishPending() const VL_MT_SAFE { return m_ns.m_finishPending.load() != 0; }
+    void finishPendingInc() VL_MT_SAFE {
+        ++m_ns.m_finishPending;
+        uint64_t unset = TIME_UNSET;
+        m_ns.m_finishPendingTime.compare_exchange_strong(unset, time());
+    }
+    void finishPendingDec() VL_MT_SAFE {
+        const uint32_t previous = m_ns.m_finishPending.fetch_sub(1);
+        assert(previous > 0);
+        if (previous == 1 && !gotFinish()) m_ns.m_finishPendingTime = TIME_UNSET;
+    }
+    // Internal: Time of the first termination request, else the current time
+    uint64_t finishPendingTime() const VL_MT_SAFE {
+        const uint64_t stamped = m_ns.m_finishPendingTime.load();
+        return stamped == TIME_UNSET ? time() : stamped;
+    }
+    // Internal: Reserve a posted $stop, returning true if it reaches the termination limit
+    bool stopRequestReserve(bool maybe) VL_MT_SAFE;
+    void stopRequestRelease() VL_MT_SAFE;
+
     // Internal: access to implementation class
     VerilatedContextImp* impp() VL_MT_SAFE { return reinterpret_cast<VerilatedContextImp*>(this); }
     const VerilatedContextImp* impp() const VL_MT_SAFE {
@@ -756,6 +806,8 @@ public:  // But for internal use only
 // Verilator scope information class
 // Used for internal VPI implementation, and introspection into scopes
 
+struct VlScopeTableEntry;  // Defined below VerilatedScope; used by scopesConstructFromTable()
+
 class VerilatedScope final {
 public:
     enum Type : uint8_t {
@@ -792,6 +844,9 @@ public:  // But internals only - called from verilated modules, VerilatedSyms
                                      void* forceReadSignalData, const char* forceReadSignalName,
                                      std::pair<VerilatedVar*, VerilatedVar*> forceControlSignals,
                                      int udims, int pdims...) VL_MT_UNSAFE;
+    void varsInsertFromTable(const VlVarTableEntry* entp, size_t n, void* basep) VL_MT_UNSAFE;
+    static void scopesConstructFromTable(const VlScopeTableEntry* entp, size_t n,
+                                         VerilatedSyms* symsp) VL_MT_UNSAFE;
     // ACCESSORS
     const char* name() const VL_MT_SAFE_POSTINIT { return m_namep; }
     const char* identifier() const VL_MT_SAFE_POSTINIT { return m_identifierp; }
@@ -807,6 +862,17 @@ public:  // But internals only - called from verilated modules, VerilatedSyms
     Type type() const { return m_type; }
 };
 
+// One scope, consumed by VerilatedScope::scopesConstructFromTable(); replaces
+// per-scope 'new VerilatedScope{...}' statements, which compiles faster at scale.
+struct VlScopeTableEntry final {
+    size_t ptrOffset;  // offsetof of the target __Vscopep_* member within the Syms object
+    const char* namep;  // Scope suffix name (protected), string literal
+    const char* identp;  // Identifier with escapes removed (protected)
+    const char* defnamep;  // Definition name (SCOPE_MODULE only), else "<null>"
+    int8_t timeunit;  // Timeunit in negative power-of-10
+    VerilatedScope::Type type;
+};
+
 class VerilatedHierarchy final {
 public:
     static void add(const VerilatedScope* fromp, const VerilatedScope* top);

include/verilated.mk.in

@@ -43,7 +43,7 @@ CFG_CXXFLAGS_WEXTRA = @CFG_CXXFLAGS_WEXTRA@
 # Compiler flags that enable coroutine support
 CFG_CXXFLAGS_COROUTINES = @CFG_CXXFLAGS_COROUTINES@
 # Compiler flags when creating a precompiled header
-CFG_CXXFLAGS_PCH = -x c++-header
+CFG_CXXFLAGS_PCH = -c -x c++-header
 # Compiler option to put in front of filename to read precompiled header
 CFG_CXXFLAGS_PCH_I = @CFG_CXXFLAGS_PCH_I@
 # Compiler's filename prefix for precompiled headers, .gch if clang, empty if GCC

include/verilated_cov.h

@@ -75,24 +75,24 @@ class VerilatedCovImp;
         ccontextp->_insertp("hier", name, __VA_ARGS__); \
     } while (false)
 
-static inline void VL_COV_TOGGLE_CHG_ST_I(const int width, uint32_t* covp, const IData newData,
-                                          const IData oldData) {
+inline void VL_COV_TOGGLE_CHG_ST_I(const int width, uint32_t* covp, const IData newData,
+                                   const IData oldData) {
     const IData chgData = newData ^ oldData;
     for (int i = 0; i < width; ++i) {
         *(covp + 2 * i + ((newData >> i) & 1)) += (chgData >> i) & 1;
     }
 }
 
-static inline void VL_COV_TOGGLE_CHG_ST_Q(const int width, uint32_t* covp, const QData newData,
-                                          const QData oldData) {
+inline void VL_COV_TOGGLE_CHG_ST_Q(const int width, uint32_t* covp, const QData newData,
+                                   const QData oldData) {
     const QData chgData = newData ^ oldData;
     for (int i = 0; i < width; ++i) {
         *(covp + 2 * i + ((newData >> i) & 1)) += (chgData >> i) & 1;
     }
 }
 
-static inline void VL_COV_TOGGLE_CHG_ST_W(const int width, uint32_t* covp, WDataInP newData,
-                                          WDataInP oldData) {
+inline void VL_COV_TOGGLE_CHG_ST_W(const int width, uint32_t* covp, WDataInP newData,
+                                   WDataInP oldData) {
     for (int i = 0; i < VL_WORDS_I(width); ++i) {
         const EData chgData = newData[i] ^ oldData[i];
         if (chgData) {
@@ -104,8 +104,8 @@ static inline void VL_COV_TOGGLE_CHG_ST_W(const int width, uint32_t* covp, WData
     }
 }
 
-static inline void VL_COV_TOGGLE_CHG_MT_I(const int width, std::atomic<uint32_t>* covp,
-                                          const IData newData, const IData oldData) VL_MT_SAFE {
+inline void VL_COV_TOGGLE_CHG_MT_I(const int width, std::atomic<uint32_t>* covp,
+                                   const IData newData, const IData oldData) VL_MT_SAFE {
     const IData chgData = newData ^ oldData;
     for (int i = 0; i < width; ++i) {
         if (VL_BITISSET_I(chgData, i)) {
@@ -114,8 +114,8 @@ static inline void VL_COV_TOGGLE_CHG_MT_I(const int width, std::atomic<uint32_t>
     }
 }
 
-static inline void VL_COV_TOGGLE_CHG_MT_Q(const int width, std::atomic<uint32_t>* covp,
-                                          const QData newData, const QData oldData) VL_MT_SAFE {
+inline void VL_COV_TOGGLE_CHG_MT_Q(const int width, std::atomic<uint32_t>* covp,
+                                   const QData newData, const QData oldData) VL_MT_SAFE {
     const QData chgData = newData ^ oldData;
     for (int i = 0; i < width; ++i) {
         if (VL_BITISSET_Q(chgData, i)) {
@@ -124,8 +124,8 @@ static inline void VL_COV_TOGGLE_CHG_MT_Q(const int width, std::atomic<uint32_t>
     }
 }
 
-static inline void VL_COV_TOGGLE_CHG_MT_W(const int width, std::atomic<uint32_t>* covp,
-                                          WDataInP newData, WDataInP oldData) VL_MT_SAFE {
+inline void VL_COV_TOGGLE_CHG_MT_W(const int width, std::atomic<uint32_t>* covp, WDataInP newData,
+                                   WDataInP oldData) VL_MT_SAFE {
     for (int i = 0; i < VL_WORDS_I(width); ++i) {
         const EData chgData = newData[i] ^ oldData[i];
         if (chgData) {

include/verilated_cov_model.h

@@ -41,9 +41,13 @@ enum class VlCovBinKind : uint8_t {
 
 //=============================================================================
 // VlCoverpointIf
-/// Read-side view of a coverpoint.  The writer queries bins by index; the
-/// implementor computes names/kinds on demand.  Bounded bin count, so random
-/// access by index is the primary usage.
+/// Read-side view of a coverpoint -- a named, index-addressable set of bins
+/// with a coverage fraction.  A cross is also a coverpoint from this view: its
+/// auto cross bins (one per element of the Cartesian product of the feeding
+/// coverpoints' Normal bins) are all Normal, and their names are built on
+/// demand by concatenating the feeding coverpoints' bin names.  The writer
+/// queries bins by index; the implementor computes names/kinds on demand.
+/// Bounded bin count, so random access by index is the primary usage.
 
 class VlCoverpointIf VL_NOT_FINAL {
 public:
@@ -51,11 +55,11 @@ public:
     virtual ~VlCoverpointIf() = default;
 
     // METHODS
-    // All bins, across every set; index range [0, binCount())
-    virtual int binCount() const = 0;
-    // Bin name in declaration order (e.g. "myBin" or "b[3]")
-    virtual std::string binName(int i) const = 0;
-    virtual VlCovBinKind binKind(int i) const = 0;
+    // All bins, across every set; index range [0, binCount()).
+    virtual uint32_t binCount() const = 0;
+    // Bin name in declaration order (e.g. "myBin" or "b[3]"); for a cross,
+    // the concatenated cross bin name (e.g. "b1_x_b2_x_b3")
+    virtual std::string binName(uint32_t i) const = 0;
     // Bins covered / effective total (Normal set only) for the coverage calc
     virtual void coverageParts(double& covered, double& total) const = 0;
 };

include/verilated_covergroup.cpp

@@ -23,34 +23,57 @@
 
 #include "verilated_covergroup.h"
 
+#include "verilated.h"
+
+// This file is compiled whenever covergroups are used, with or without
+// "verilator --coverage" (see V3Global::verilatedCppFiles).  Bin counts are
+// members of the covergroup objects themselves, so sampling, bin naming, and
+// coverage queries such as get_inst_coverage() all work with no coverage
+// database present.  VL_COVER_INSERT does not copy a count; it hands the
+// database the address of a counter to read at write time.  Only that
+// publication step needs verilated_cov.cpp, which is compiled solely under
+// --coverage, so only the registerBins() bodies are gated on VM_COVERAGE.
 #if VM_COVERAGE
 #include "verilated_cov.h"
 #endif
 
-void VlCoverpoint::init(const char* hier, uint32_t atLeast, int nBins) {
+void VlCoverpoint::init(const char* hier, uint32_t atLeast, uint32_t nBins) {
     m_hier = hier;
     m_atLeast = atLeast;
     m_total = nBins;
     m_counts.assign(nBins, 0);
+    m_crossIdx.assign(nBins, -1);
+    m_crossToBin.clear();
 }
 
-void VlCoverpoint::addNamer(VlCovBinKind set, int count, VlCovBinNaming naming, const char* name,
-                            const char* file, int line, int col) {
+void VlCoverpoint::addNamer(VlCovBinKind set, uint32_t count, VlCovBinNaming naming,
+                            const char* name, const char* file, int line, int col) {
     m_namers.emplace_back(set, count, m_nextBase, naming, name, file, line, col);
+    if (set == VlCovBinKind::KIND_NORMAL) {
+        // Assign each Normal bin a cross index, and record the inverse map.
+        for (uint32_t b = m_nextBase; b < m_nextBase + count; ++b) {
+            m_crossIdx[b] = static_cast<int>(m_crossToBin.size());
+            m_crossToBin.push_back(b);
+        }
+        m_normal += count;
+    }
     m_nextBase += count;
-    if (set == VlCovBinKind::KIND_NORMAL) m_normal += count;
 }
 
-const VlCovNamer& VlCoverpoint::namerFor(int i) const {
-    // Namers are appended in ascending, contiguous index order covering [0, m_total),
-    // and i is always a valid bin index, so the matching namer always exists.
+std::string VlCoverpoint::normalBinName(uint32_t crossIdx) const {
+    // Build the bin name based on the bin index
+    return binName(m_crossToBin[crossIdx]);
+}
+
+const VlCovNamer& VlCoverpoint::namerFor(uint32_t i) const {
+    // Namers are appended in ascending order covering [0, m_total),
     for (const VlCovNamer& nm : m_namers) {
         if (i < nm.base() + nm.count()) return nm;
     }
-    VL_UNREACHABLE;
+    VL_UNREACHABLE;  // LCOV_EXCL_LINE
 }
 
-std::string VlCoverpoint::binName(int i) const {
+std::string VlCoverpoint::binName(uint32_t i) const {
     const VlCovNamer& nm = namerFor(i);
     std::string name = nm.name();
     if (nm.naming() == VlCovBinNaming::Array) name += '[' + std::to_string(i - nm.base()) + ']';
@@ -59,7 +82,7 @@ std::string VlCoverpoint::binName(int i) const {
 
 #if VM_COVERAGE
 void VlCoverpoint::registerBins(VerilatedCovContext* covcontextp, const char* page) {
-    for (int i = 0; i < binCount(); ++i) {
+    for (uint32_t i = 0; i < binCount(); ++i) {
         const VlCovNamer& nm = namerFor(i);
         const VlCovBinKind kind = binKind(i);
         const std::string binp = binName(i);
@@ -81,3 +104,89 @@ void VlCoverpoint::registerBins(VerilatedCovContext* covcontextp, const char* pa
     }
 }
 #endif  // VM_COVERAGE
+
+//=============================================================================
+// VlCoverCross
+
+void VlCoverCross::init(const char* hier, uint32_t dims, VlCoverpoint* const* cps,
+                        const char* file, int line, int col) {
+    m_hier = hier;
+    m_file = file;
+    m_line = line;
+    m_col = col;
+    m_dims = dims;
+    m_cps.assign(cps, cps + dims);
+    m_cpBinCounts.resize(dims);
+    // Accumulate in 64 bits so the overflow check itself cannot overflow.
+    uint64_t product = 1;
+    for (uint32_t d = 0; d < dims; ++d) {
+        m_cpBinCounts[d] = cps[d]->normalBinCount();
+        product *= m_cpBinCounts[d];
+        if (VL_UNLIKELY(product > UINT32_MAX)) {  // LCOV_EXCL_START
+            VL_FATAL_MT(file, line, "", "Cross has too many auto bins to represent");
+        }  // LCOV_EXCL_STOP
+    }
+    m_numAutoBins = static_cast<uint32_t>(product);
+    // stride[d] = product of the Normal bin counts of all dimensions after d.
+    // Counts down with an offset so the unsigned index never wraps below zero.
+    m_stride.assign(dims, 1);
+    for (uint32_t d = dims; d > 1; --d) m_stride[d - 2] = m_stride[d - 1] * m_cpBinCounts[d - 1];
+    m_flatCounts.assign(m_numAutoBins, 0);
+}
+
+void VlCoverCross::iterateProduct(VlCoverpoint* const* cps, uint32_t dim, uint32_t baseIdx) {
+    const uint32_t hits = cps[dim]->hitCount();
+    const uint32_t* const list = cps[dim]->hitList();
+    const bool last = (dim == m_dims - 1);
+    const uint32_t stride = m_stride[dim];
+    for (uint32_t hit = 0; hit < hits; ++hit) {
+        const uint32_t idx = baseIdx + list[hit] * stride;
+        if (last) {
+            incrementTuple(idx);
+        } else {
+            iterateProduct(cps, dim + 1, idx);
+        }
+    }
+}
+
+void VlCoverCross::sample(VlCoverpoint* const* cps) {
+    // Fast path: if any dimension had no Normal-bin hit, the cross cannot hit.
+    for (uint32_t d = 0; d < m_dims; ++d) {
+        if (cps[d]->hitCount() == 0) return;
+    }
+    iterateProduct(cps, 0, 0);
+}
+
+std::string VlCoverCross::binName(uint32_t flat) const {
+    // Built on demand by concatenating each coverpoint's own bin name.
+    std::string name;
+    for (uint32_t d = 0; d < m_dims; ++d) {
+        const uint32_t crossIdx = (flat / m_stride[d]) % m_cpBinCounts[d];
+        if (d > 0) name += "_x_";
+        name += m_cps[d]->normalBinName(crossIdx);
+    }
+    return name;
+}
+
+#if VM_COVERAGE
+void VlCoverCross::registerBins(VerilatedCovContext* covcontextp, const char* page) {
+    // Register every auto cross bin (zero-count bins included), so the report
+    // shows the full Cartesian product of cross bins.  Names are built on the fly.
+    const std::string lineStr = std::to_string(m_line);
+    const std::string colStr = std::to_string(m_col);
+    for (uint32_t flat = 0; flat < binCount(); ++flat) {
+        const std::string bin = binName(flat);  // "b1_x_b2_x_..."
+        // cross_bins metadata: the same components joined by ',' (not read by the report)
+        std::string crossBins;
+        for (uint32_t d = 0; d < m_dims; ++d) {
+            const uint32_t crossIdx = (flat / m_stride[d]) % m_cpBinCounts[d];
+            if (d > 0) crossBins += ",";
+            crossBins += m_cps[d]->normalBinName(crossIdx);
+        }
+        const std::string full = m_hier + "." + bin;
+        VL_COVER_INSERT(covcontextp, full.c_str(), &m_flatCounts[flat], "page", page, "filename",
+                        m_file, "lineno", lineStr.c_str(), "column", colStr.c_str(), "bin",
+                        bin.c_str(), "cross", "1", "cross_bins", crossBins.c_str());
+    }
+}
+#endif  // VM_COVERAGE

include/verilated_covergroup.h

@@ -22,6 +22,9 @@
 /// it in the constructor (init + add*Namer), increments bins from sample(),
 /// and registers via registerBins().
 ///
+/// Collection and coverage queries are always available; only registerBins(),
+/// which publishes bin counters to the coverage database, requires VM_COVERAGE.
+///
 //=============================================================================
 
 #ifndef VERILATOR_VERILATED_COVERGROUP_H_
@@ -49,8 +52,8 @@ enum class VlCovBinNaming : uint8_t {
 class VlCovNamer final {
     // MEMBERS
     VlCovBinKind m_set;  // which set the bins belong to
-    int m_count;  // bins this namer covers (1 for Single)
-    int m_base;  // first bin index (declaration order), assigned on append
+    uint32_t m_count;  // bins this namer covers (1 for Single)
+    uint32_t m_base;  // first bin index (declaration order), assigned on append
     VlCovBinNaming m_naming;  // how bin names are built
     const char* m_name;  // bin name (Single) or array base name (Array)
     const char* m_file;  // declaration file
@@ -59,8 +62,8 @@ class VlCovNamer final {
 
 public:
     // CONSTRUCTORS
-    VlCovNamer(VlCovBinKind set, int count, int base, VlCovBinNaming naming, const char* name,
-               const char* file, int line, int col)
+    VlCovNamer(VlCovBinKind set, uint32_t count, uint32_t base, VlCovBinNaming naming,
+               const char* name, const char* file, int line, int col)
         : m_set{set}
         , m_count{count}
         , m_base{base}
@@ -72,8 +75,8 @@ public:
 
     // METHODS
     VlCovBinKind set() const { return m_set; }
-    int count() const { return m_count; }
-    int base() const { return m_base; }
+    uint32_t count() const { return m_count; }
+    uint32_t base() const { return m_base; }
     VlCovBinNaming naming() const { return m_naming; }
     const char* name() const { return m_name; }
     const char* file() const { return m_file; }
@@ -87,19 +90,30 @@ public:
 /// bin's set/name come from the owning namer.  coverage() is computed on demand
 /// by scanning bin counts, keeping the sample() hot path a plain counter bump.
 
-class VlCoverpoint final : public VlCoverpointIf {
-    // MEMBERS
+// Base coverpoint runtime (read side + collection logic, no hit-list storage).
+// VlCoverpointT<MaxHits> adds the inline hit-list array and the incrementBin write
+// path; the cross holds VlCoverpoint* and reads via hitCount()/hitList().
+class VlCoverpoint VL_NOT_FINAL : public VlCoverpointIf {
+protected:
+    // MEMBERS (protected so VlCoverpointT::incrementBin can update them)
     std::string m_hier;  // "covergroup.coverpoint"
     uint32_t m_atLeast = 1;  // option.at_least (coverpoint-wide)
-    int m_total = 0;  // bins across all sets
-    int m_normal = 0;  // Normal bins (coverage denominator)
-    int m_nextBase = 0;  // running append cursor
+    uint32_t m_total = 0;  // bins across all sets
+    uint32_t m_normal = 0;  // Normal bins (coverage denominator)
+    uint32_t m_nextBase = 0;  // running append cursor
     std::vector<uint32_t> m_counts;  // [m_total], one per bin
     std::vector<VlCovNamer> m_namers;  // appended in declaration order
+    // [m_total] full bin idx -> cross idx (Normal-only), -1 otherwise.  The only
+    // signed index here: -1 marks a non-Normal bin, which incrementBin filters on.
+    std::vector<int> m_crossIdx;
+    // [m_normal] inverse of m_crossIdx: cross idx -> full bin idx, appended in cross-index order
+    std::vector<uint32_t> m_crossToBin;
+    uint32_t m_hitCount = 0;  // entries valid in the hit list this sample
 
+private:
     // PRIVATE METHODS
-    const VlCovNamer& namerFor(int i) const;  // obtain the bin-specific name producer
-    void addNamer(VlCovBinKind set, int count, VlCovBinNaming naming, const char* name,
+    const VlCovNamer& namerFor(uint32_t i) const;  // obtain the bin-specific name producer
+    void addNamer(VlCovBinKind set, uint32_t count, VlCovBinNaming naming, const char* name,
                   const char* file, int line, int col);
 
 public:
@@ -108,31 +122,44 @@ public:
 
     // METHODS
     // ---- configuration (from generated constructor) ----
-    void init(const char* hier, uint32_t atLeast, int nBins);
+    void init(const char* hier, uint32_t atLeast, uint32_t nBins);
     void addSingleNamer(VlCovBinKind set, const char* name, const char* file, int line, int col) {
         addNamer(set, 1, VlCovBinNaming::Single, name, file, line, col);
     }
-    void addArrayNamer(VlCovBinKind set, int count, const char* name, const char* file, int line,
-                       int col) {
+    void addArrayNamer(VlCovBinKind set, uint32_t count, const char* name, const char* file,
+                       int line, int col) {
         addNamer(set, count, VlCovBinNaming::Array, name, file, line, col);
     }
     void registerBins(VerilatedCovContext* covcontextp, const char* page);
 
     // ---- hot path (from generated sample()) ----
-    void incrementBin(int i) { ++m_counts[i]; }  // Normal bin: count only
-    void recordHit(int i) { ++m_counts[i]; }  // Ignore/Illegal/Default: count only
+    // Clear the hit list at the start of each sample() for a cross-fed coverpoint.
+    void clearHitList() { m_hitCount = 0; }
+    // Ignore/Illegal/Default: count only; never propagates to cross coverage.
+    void recordHit(uint32_t i) { ++m_counts[i]; }
+    // incrementBin (Normal bin: count + hit-list append) lives in VlCoverpointT<MaxHits>,
+    // where MaxHits is the gen-time max per-sample bin overlap.
+
+    // ---- cross support (read by VlCoverCross) ----
+    uint32_t hitCount() const { return m_hitCount; }
+    virtual const uint32_t* hitList() const = 0;  // provided by VlCoverpointT
+    uint32_t normalBinCount() const { return m_normal; }  // cross dimension size (Normal bins)
+    std::string normalBinName(uint32_t crossIdx) const;  // name of the crossIdx-th Normal bin
 
     // ---- VlCoverpointIf ----
-    int binCount() const override { return m_total; }
-    std::string binName(int i) const override;
-    VlCovBinKind binKind(int i) const override { return namerFor(i).set(); }
+    uint32_t binCount() const override { return m_total; }
+    std::string binName(uint32_t i) const override;
+    // Deliberately not on VlCoverpointIf: only registerBins() needs it, via the
+    // concrete coverpoint.  A cross has all-Normal bins and exposes no kind, so the
+    // interface omits it; add it back only if a writer needs it polymorphically.
+    VlCovBinKind binKind(uint32_t i) const { return namerFor(i).set(); }
     void coverageParts(double& covered, double& total) const override {
         // Count Normal bins that reached option.at_least on demand, so the hot
         // path (incrementBin) stays a plain counter bump.
-        int numCovered = 0;
+        uint32_t numCovered = 0;
         for (const VlCovNamer& nm : m_namers) {
             if (nm.set() != VlCovBinKind::KIND_NORMAL) continue;
-            for (int i = nm.base(); i < nm.base() + nm.count(); ++i) {
+            for (uint32_t i = nm.base(); i < nm.base() + nm.count(); ++i) {
                 if (m_counts[i] >= m_atLeast) ++numCovered;
             }
         }
@@ -141,4 +168,90 @@ public:
     }
 };
 
+//=============================================================================
+// VlCoverpointT
+/// Concrete coverpoint with an inline hit-list array sized to MaxHits -- the
+/// gen-time maximum number of Normal bins one sample value can match (1 for the
+/// common non-overlapping case).  The bound is a compile-time constant, so for
+/// MaxHits == 1 incrementBin collapses to a single store.  Generated code holds
+/// the coverpoint as VlCoverpointT<K> and calls incrementBin via the concrete
+/// type; the cross reads it polymorphically through VlCoverpoint*.
+
+template <uint32_t MaxHits>
+class VlCoverpointT final : public VlCoverpoint {
+    // MEMBERS
+    uint32_t m_hits[MaxHits];  // cross indices of Normal bins hit this sample
+
+public:
+    // CONSTRUCTORS
+    VlCoverpointT() = default;
+
+    // METHODS
+    // Normal bin: bump count and append the bin's cross index to the hit list.
+    // m_hitCount can never exceed MaxHits (the gen-time overlap bound), so no hit
+    // is ever dropped; the bound check is a compile-time-folded safety net.
+    void incrementBin(uint32_t i) {
+        ++m_counts[i];
+        // m_crossIdx is signed only to carry the -1 "not a Normal bin" marker;
+        // the >= 0 test below is what makes every stored hit index unsigned-safe.
+        const int cx = m_crossIdx[i];
+        if (cx >= 0 && m_hitCount < MaxHits) m_hits[m_hitCount++] = static_cast<uint32_t>(cx);
+    }
+    const uint32_t* hitList() const override { return m_hits; }
+};
+
+//=============================================================================
+// VlCoverCross
+/// Per-instance auto cross runtime.  Holds flat uint32_t[] storage over the
+/// Cartesian product of the feeding coverpoints' Normal bins.  Each sample()
+/// walks the coverpoint hit lists (O(hits), not O(product)).  Bin names are
+/// built on demand from the coverpoints, so no per-bin name is stored.
+
+class VlCoverCross final : public VlCoverpointIf {
+    // MEMBERS
+    std::string m_hier;  // "covergroup.cross"
+    const char* m_file = nullptr;  // Cross declaration file (registration metadata)
+    int m_line = 0;  // Cross declaration line
+    int m_col = 0;  // Cross declaration column
+    uint32_t m_dims = 0;  // Number of feeding coverpoints
+    // Cross bin indexes are unsigned, like the coverpoint bin indexes they are
+    // built from.  init() fatals if the product would exceed UINT32_MAX, so every
+    // index computed here provably fits.  That bound is far beyond anything
+    // storable anyway: m_flatCounts alone would need 16GB.
+    uint32_t m_numAutoBins = 0;  // Product of per-dim Normal bin counts
+    uint32_t m_numCovered = 0;  // Distinct bins hit >= 1 (maintained incrementally)
+    std::vector<uint32_t> m_cpBinCounts;  // [m_dims] Normal bin count per dimension
+    std::vector<uint32_t> m_stride;  // [m_dims] Flat-index stride per dimension
+    std::vector<uint32_t> m_flatCounts;  // [m_numAutoBins] Per-bin hit counts
+    std::vector<VlCoverpoint*> m_cps;  // Feeding coverpoints (the only name source)
+
+    // PRIVATE METHODS
+    void iterateProduct(VlCoverpoint* const* cps, uint32_t dim, uint32_t baseIdx);
+    void incrementTuple(uint32_t idx) {
+        if (m_flatCounts[idx]++ == 0) ++m_numCovered;
+    }
+
+public:
+    // CONSTRUCTORS
+    VlCoverCross() = default;
+
+    // METHODS
+    // ---- configuration (from generated constructor, after coverpoints init'd) ----
+    void init(const char* hier, uint32_t dims, VlCoverpoint* const* cps, const char* file,
+              int line, int col);
+    void registerBins(VerilatedCovContext* covcontextp, const char* page);
+
+    // ---- hot path (from generated sample(), after all coverpoints sampled) ----
+    void sample(VlCoverpoint* const* cps);
+
+    // ---- VlCoverpointIf ----
+    // A cross is a coverpoint whose bins are the auto cross bins (all Normal).
+    uint32_t binCount() const override { return m_numAutoBins; }
+    std::string binName(uint32_t flat) const override;
+    void coverageParts(double& covered, double& total) const override {
+        covered = m_numCovered;
+        total = m_numAutoBins;
+    }
+};
+
 #endif  // Guard

include/verilated_dpi.h

@@ -37,68 +37,68 @@
 // SETTING OPERATORS
 
 // Convert svBitVecVal to Verilator internal data
-static inline void VL_SET_W_SVBV(int obits, WDataOutP owp, const svBitVecVal* lwp) VL_MT_SAFE {
+inline void VL_SET_W_SVBV(int obits, WDataOutP owp, const svBitVecVal* lwp) VL_MT_SAFE {
     const int words = VL_WORDS_I(obits);
     for (int i = 0; i < words - 1; ++i) owp[i] = lwp[i];
     owp[words - 1] = lwp[words - 1] & VL_MASK_I(obits);
 }
-static inline void VL_SET_Q_SVBV(int obits, QData& out, const svBitVecVal* lwp) VL_MT_SAFE {
+inline void VL_SET_Q_SVBV(int obits, QData& out, const svBitVecVal* lwp) VL_MT_SAFE {
     out = VL_MASK_Q(obits) & VL_SET_QII(lwp[1], lwp[0]);
 }
-static inline void VL_SET_I_SVBV(int obits, IData& out, const svBitVecVal* lwp) VL_MT_SAFE {
+inline void VL_SET_I_SVBV(int obits, IData& out, const svBitVecVal* lwp) VL_MT_SAFE {
     out = VL_MASK_I(obits) & lwp[0];
 }
-static inline void VL_SET_S_SVBV(int obits, SData& out, const svBitVecVal* lwp) VL_MT_SAFE {
+inline void VL_SET_S_SVBV(int obits, SData& out, const svBitVecVal* lwp) VL_MT_SAFE {
     out = VL_MASK_I(obits) & lwp[0];
 }
-static inline void VL_SET_C_SVBV(int obits, CData& out, const svBitVecVal* lwp) VL_MT_SAFE {
+inline void VL_SET_C_SVBV(int obits, CData& out, const svBitVecVal* lwp) VL_MT_SAFE {
     out = VL_MASK_I(obits) & lwp[0];
 }
 
 // Convert Verilator internal data to svBitVecVal
-static inline void VL_SET_SVBV_W(int obits, svBitVecVal* owp, const WDataInP lwp) VL_MT_SAFE {
+inline void VL_SET_SVBV_W(int obits, svBitVecVal* owp, const WDataInP lwp) VL_MT_SAFE {
     const int words = VL_WORDS_I(obits);
     for (int i = 0; i < words - 1; ++i) owp[i] = lwp[i];
     owp[words - 1] = lwp[words - 1] & VL_MASK_I(obits);
 }
-static inline void VL_SET_SVBV_I(int, svBitVecVal* owp, const IData ld) VL_MT_SAFE { owp[0] = ld; }
-static inline void VL_SET_SVBV_Q(int, svBitVecVal* owp, const QData ld) VL_MT_SAFE {
+inline void VL_SET_SVBV_I(int, svBitVecVal* owp, const IData ld) VL_MT_SAFE { owp[0] = ld; }
+inline void VL_SET_SVBV_Q(int, svBitVecVal* owp, const QData ld) VL_MT_SAFE {
     VL_SET_WQ(WDataOutP::external(owp), ld);
 }
 
 // Convert svLogicVecVal to Verilator internal data
 // Note these functions ignore X/Z in svLogicVecVal
-static inline void VL_SET_W_SVLV(int obits, WDataOutP owp, const svLogicVecVal* lwp) VL_MT_SAFE {
+inline void VL_SET_W_SVLV(int obits, WDataOutP owp, const svLogicVecVal* lwp) VL_MT_SAFE {
     const int words = VL_WORDS_I(obits);
     for (int i = 0; i < words - 1; ++i) owp[i] = lwp[i].aval;
     owp[words - 1] = lwp[words - 1].aval & VL_MASK_I(obits);
 }
-static inline void VL_SET_Q_SVLV(int obits, QData& out, const svLogicVecVal* lwp) VL_MT_SAFE {
+inline void VL_SET_Q_SVLV(int obits, QData& out, const svLogicVecVal* lwp) VL_MT_SAFE {
     out = VL_MASK_Q(obits) & VL_SET_QII(lwp[1].aval, lwp[0].aval);
 }
-static inline void VL_SET_I_SVLV(int obits, IData& out, const svLogicVecVal* lwp) VL_MT_SAFE {
+inline void VL_SET_I_SVLV(int obits, IData& out, const svLogicVecVal* lwp) VL_MT_SAFE {
     out = VL_MASK_I(obits) & lwp[0].aval;
 }
-static inline void VL_SET_S_SVLV(int obits, SData& out, const svLogicVecVal* lwp) VL_MT_SAFE {
+inline void VL_SET_S_SVLV(int obits, SData& out, const svLogicVecVal* lwp) VL_MT_SAFE {
     out = VL_MASK_I(obits) & lwp[0].aval;
 }
-static inline void VL_SET_C_SVLV(int obits, CData& out, const svLogicVecVal* lwp) VL_MT_SAFE {
+inline void VL_SET_C_SVLV(int obits, CData& out, const svLogicVecVal* lwp) VL_MT_SAFE {
     out = VL_MASK_I(obits) & lwp[0].aval;
 }
 
 // Convert Verilator internal data to svLogicVecVal
 // Note these functions never create X/Z in svLogicVecVal
-static inline void VL_SET_SVLV_W(int obits, svLogicVecVal* owp, const WDataInP lwp) VL_MT_SAFE {
+inline void VL_SET_SVLV_W(int obits, svLogicVecVal* owp, const WDataInP lwp) VL_MT_SAFE {
     const int words = VL_WORDS_I(obits);
     for (int i = 0; i < words; ++i) owp[i].bval = 0;
     for (int i = 0; i < words - 1; ++i) owp[i].aval = lwp[i];
     owp[words - 1].aval = lwp[words - 1] & VL_MASK_I(obits);
 }
-static inline void VL_SET_SVLV_I(int, svLogicVecVal* owp, const IData ld) VL_MT_SAFE {
+inline void VL_SET_SVLV_I(int, svLogicVecVal* owp, const IData ld) VL_MT_SAFE {
     owp[0].aval = ld;
     owp[0].bval = 0;
 }
-static inline void VL_SET_SVLV_Q(int, svLogicVecVal* owp, const QData ld) VL_MT_SAFE {
+inline void VL_SET_SVLV_Q(int, svLogicVecVal* owp, const QData ld) VL_MT_SAFE {
     VlWide<2> lwp;
     VL_SET_WQ(lwp, ld);
     owp[0].aval = lwp[0];

include/verilated_fst_c.cpp

@@ -98,8 +98,10 @@ void VerilatedFst::close() VL_MT_SAFE_EXCLUDES(m_mutex) {
     const VerilatedLockGuard lock{m_mutex};
     Super::closeBase();
     emitTimeChangeMaybe();
-    if (m_fst) m_fst->close();  // LCOV_EXCL_BR_LINE
-    m_fst = nullptr;
+    if (m_fst) {
+        m_fst->close();
+        VL_DO_CLEAR(delete m_fst, m_fst = nullptr);
+    }
 }
 
 void VerilatedFst::flush() VL_MT_SAFE_EXCLUDES(m_mutex) {

include/verilated_random.cpp

@@ -129,7 +129,7 @@ public:
     void wait_report() {
         if (m_pidExited) return;
 #ifdef _VL_SOLVER_PIPE
-        if (waitpid(m_pid, &m_pidStatus, 0) != m_pid) return;
+        if (waitpid(m_pid, &m_pidStatus, WNOHANG) != m_pid) m_pidStatus = 0;
         if (m_pidStatus) {
             std::stringstream msg;
             msg << "Subprocess command `" << m_cmd[0];
@@ -208,8 +208,10 @@ public:
             // Child
             close(fd_stdin[P_WR]);
             dup2(fd_stdin[P_RD], STDIN_FILENO);
+            close(fd_stdin[P_RD]);
             close(fd_stdout[P_RD]);
             dup2(fd_stdout[P_WR], STDOUT_FILENO);
+            close(fd_stdout[P_WR]);
             execvp(cmd[0], const_cast<char* const*>(cmd));
             std::stringstream msg;
             msg << "VlRProcess::open: execvp(" << cmd[0] << ")";
@@ -441,11 +443,14 @@ void VlRandomizer::randomConstraint(std::ostream& os, VlRNG& rngr, int bits) {
     os << ')';
 }
 
-size_t VlRandomizer::hashConstraints() const {
+size_t VlRandomizer::hashConstraints(const std::vector<std::string>& extras) const {
     size_t h = 0;
     for (const auto& c : m_constraints) {
         h ^= std::hash<std::string>{}(c) + 0x9e3779b9 + (h << 6) + (h >> 2);
     }
+    for (const auto& c : extras) {
+        h ^= std::hash<std::string>{}(c) + 0x9e3779b9 + (h << 6) + (h >> 2);
+    }
     return h;
 }
 
@@ -478,36 +483,20 @@ void VlRandomizer::recordRandcValues() {
     }
 }
 
-bool VlRandomizer::next_check_only(VlRNG& rngr) {
-    m_checkOnly = true;
-    const bool result = next(rngr);
-    m_checkOnly = false;
-    return result;
-}
+bool VlRandomizer::next_check_only(VlRNG& rngr) { return nextRandomize(rngr, true); }
 
-bool VlRandomizer::next(VlRNG& rngr) {
-    if (!m_checkOnly && m_vars.empty() && m_unique_arrays.empty()) return true;
-    if (m_checkOnly && m_vars.empty()) return true;  // No rand members: trivially SAT
-    for (const std::string& baseName : m_unique_arrays) {
-        const auto it = m_vars.find(baseName);
-        const uint32_t size = m_unique_array_sizes.at(baseName);
+bool VlRandomizer::next(VlRNG& rngr) { return nextRandomize(rngr, false); }
 
-        if (it != m_vars.end()) {
-            std::string distinctExpr = "(__Vbv (distinct";
-            for (uint32_t i = 0; i < size; ++i) {
-                char hexIdx[12];
-                sprintf(hexIdx, "#x%08x", i);
-                distinctExpr += " (select " + it->first + " " + hexIdx + ")";
-            }
-            distinctExpr += "))";
-            m_constraints.push_back(distinctExpr);
-        }
-    }
+bool VlRandomizer::nextRandomize(VlRNG& rngr, bool checkOnly) {
+    if (!checkOnly && m_vars.empty() && m_unique_arrays.empty()) return true;
+    if (checkOnly && m_vars.empty()) return true;  // No rand members: trivially SAT
+    m_checkOnly = checkOnly;
+    const std::vector<std::string> uniqueExprs = buildUniqueExprs();
 
     // Randc exclusion-based cycling: exclude previously used values per randc var.
     // When solver returns unsat (all values exhausted), clear history for new cycle.
     if (!m_randcVarNames.empty()) {
-        const size_t currentHash = hashConstraints();
+        const size_t currentHash = hashConstraints(uniqueExprs);
         // Invalidate history if constraints changed (e.g., constraint_mode toggled)
         if (currentHash != m_randcConstraintHash) {
             m_randcUsedValues.clear();
@@ -516,83 +505,103 @@ bool VlRandomizer::next(VlRNG& rngr) {
     }
 
     // Pinned vars make phase ordering moot; skip phased path in check-only.
-    if (!m_checkOnly && !m_solveBefore.empty()) return nextPhased(rngr);
+    bool result;
+    if (!m_checkOnly && !m_solveBefore.empty()) {
+        result = nextPhased(rngr, uniqueExprs);
+    } else {
+        result = nextFlat(rngr, uniqueExprs);
+    }
+    m_checkOnly = false;
+    return result;
+}
 
+std::vector<std::string> VlRandomizer::buildUniqueExprs() const {
+    std::vector<std::string> exprs;
+    if (m_unique_arrays.empty()) return exprs;
+    const auto arrVarsp = std::make_shared<const ArrayInfoMap>(m_arr_vars);
+    for (const std::string& baseName : m_unique_arrays) {
+        const auto it = m_vars.find(baseName);
+        if (it == m_vars.end()) continue;
+        const VlRandomVar& var = *it->second;
+        // Select the elements the array actually holds now, by their own index
+        // or key, rather than by ordinal position
+        var.setArrayInfo(arrVarsp);
+        // 'distinct' needs at least two operands; fewer elements are trivially unique
+        if (var.countMatchingElements(*arrVarsp, baseName) < 2) continue;
+        std::ostringstream os;
+        os << "(__Vbv (distinct ";
+        var.emitGetValue(os);
+        os << "))";
+        exprs.push_back(os.str());
+    }
+    return exprs;
+}
+
+void VlRandomizer::emitDefines(std::ostream& os) const {
+    os << "(define-fun __Vbv ((b Bool)) (_ BitVec 1) (ite b #b1 #b0))\n";
+    os << "(define-fun __Vbool ((v (_ BitVec 1))) Bool (= #b1 v))\n";
+}
+
+void VlRandomizer::emitDeclares(std::ostream& os, bool pinCurrent) const {
+    for (const auto& var : m_vars) {
+        if (var.second->dimension() > 0) {
+            auto arrVarsp = std::make_shared<const ArrayInfoMap>(m_arr_vars);
+            var.second->setArrayInfo(arrVarsp);
+        }
+        os << "(declare-fun " << var.first << " () ";
+        var.second->emitType(os);
+        os << ")\n";
+        // Pin each var to its current value
+        if (pinCurrent) {
+            assert(var.second->dimension() == 0);
+            os << "(assert (= " << var.first << ' ';
+            var.second->emitConcreteValue(os);
+            os << "))\n";
+        }
+    }
+}
+
+void VlRandomizer::emitAsserts(std::ostream& os, const std::vector<std::string>& extras,
+                               bool named) const {
+    int j = 0;
+    for (const std::string& constraint : m_constraints) {
+        if (named) {
+            os << "(assert (! (= #b1 " << constraint << ") :named cons" << j++ << "))\n";
+        } else {
+            os << "(assert (= #b1 " << constraint << "))\n";
+        }
+    }
+    for (const std::string& extra : extras) {
+        if (named) {
+            os << "(assert (! (= #b1 " << extra << ") :named cons" << j++ << "))\n";
+        } else {
+            os << "(assert (= #b1 " << extra << "))\n";
+        }
+    }
+}
+
+bool VlRandomizer::nextFlat(VlRNG& rngr, const std::vector<std::string>& uniqueExprs) {
     // Randc retry: if unsat due to randc exhaustion, clear history and retry once
     const bool hasRandc = !m_randcVarNames.empty();
     for (int attempt = 0; attempt < (hasRandc ? 2 : 1); ++attempt) {
         std::iostream& os = getSolver();
         if (!os) return false;
 
-        // Soft constraint relaxation (IEEE 1800-2023 18.5.13, last-wins priority):
-        // Try hard + soft[0..N-1], then hard + soft[1..N-1], ..., then hard only.
-        // First SAT phase wins. If hard-only is UNSAT, report via unsat-core.
         os << "(set-option :produce-models true)\n";
         // Lets the scalar pin path learn which free-bit assumptions conflict.
         os << "(set-option :produce-unsat-assumptions true)\n";
         os << "(set-logic QF_ABV)\n";
-        os << "(define-fun __Vbv ((b Bool)) (_ BitVec 1) (ite b #b1 #b0))\n";
-        os << "(define-fun __Vbool ((v (_ BitVec 1))) Bool (= #b1 v))\n";
-        for (const auto& var : m_vars) {
-            if (var.second->dimension() > 0) {
-                auto arrVarsp = std::make_shared<const ArrayInfoMap>(m_arr_vars);
-                var.second->setArrayInfo(arrVarsp);
-            }
-            os << "(declare-fun " << var.first << " () ";
-            var.second->emitType(os);
-            os << ")\n";
-            // Pin each var to its current value: SAT iff the current values
-            // satisfy the constraints. V3Randomize rejects non-scalar rand
-            // members upstream, hence the assert.
-            if (m_checkOnly) {
-                assert(var.second->dimension() == 0);
-                os << "(assert (= " << var.first << ' ';
-                var.second->emitConcreteValue(os);
-                os << "))\n";
-            }
-        }
-
-        for (const std::string& constraint : m_constraints) {
-            os << "(assert (= #b1 " << constraint << "))\n";
-        }
+        emitDefines(os);
+        emitDeclares(os, m_checkOnly);
+        emitAsserts(os, uniqueExprs, false);
 
         // randc exclusions vs. a pinned current value would make every check
         // trivially UNSAT after the first cycle.
         if (!m_checkOnly) emitRandcExclusions(os);
 
-        const size_t nSoft = m_softConstraints.size();
-        bool sat = false;
-        if (nSoft > 0) {
-            // Fast path: try all soft constraints at once
-            os << "(push 1)\n";
-            for (const auto& s : m_softConstraints) os << "(assert (= #b1 " << s << "))\n";
-            os << "(check-sat)\n";
-            sat = parseSolution(os, false);
-            if (!sat) {
-                // Some soft constraints conflict. Incrementally add from back
-                // (highest priority first), keeping only compatible ones.
-                // This preserves the maximum set of compatible soft constraints.
-                os << "(pop 1)\n";
-                for (int i = static_cast<int>(nSoft) - 1; i >= 0; --i) {
-                    os << "(push 1)\n";
-                    os << "(assert (= #b1 " << m_softConstraints[i] << "))\n";
-                    os << "(check-sat)\n";
-                    if (checkSat(os)) {
-                        // Compatible -- keep this push level
-                    } else {
-                        // Incompatible -- remove this soft constraint
-                        os << "(pop 1)\n";
-                    }
-                }
-                // Read solution with remaining compatible soft constraints
-                os << "(check-sat)\n";
-                sat = parseSolution(os, false);
-            }
-        } else {
-            // No soft constraints -- hard-only
-            os << "(check-sat)\n";
-            sat = parseSolution(os, false);
-        }
+        relaxSoftConstraints(os);
+        os << "(check-sat)\n";
+        const bool sat = parseSolution(os);
 
         if (!sat) {
             os << "(reset)\n";
@@ -606,116 +615,120 @@ bool VlRandomizer::next(VlRNG& rngr) {
             // the solver's free assignment.
             if (m_checkOnly) return false;
             // Genuine unsat: report via unsat-core
-            os << "(set-option :produce-unsat-cores true)\n";
-            os << "(set-logic QF_ABV)\n";
-            os << "(define-fun __Vbv ((b Bool)) (_ BitVec 1) (ite b #b1 #b0))\n";
-            os << "(define-fun __Vbool ((v (_ BitVec 1))) Bool (= #b1 v))\n";
-            for (const auto& var : m_vars) {
-                if (var.second->dimension() > 0) {
-                    auto arrVarsp = std::make_shared<const ArrayInfoMap>(m_arr_vars);
-                    var.second->setArrayInfo(arrVarsp);
-                }
-                os << "(declare-fun " << var.first << " () ";
-                var.second->emitType(os);
-                os << ")\n";
-            }
-            int j = 0;
-            for (const std::string& constraint : m_constraints) {
-                os << "(assert (! (= #b1 " << constraint << ") :named cons" << j++ << "))\n";
-            }
-            os << "(check-sat)\n";
-            sat = parseSolution(os, true);
-            (void)sat;
+            reportUnsatSetup(os, uniqueExprs);
             os << "(reset)\n";
             return false;
         }
 
         if (!m_checkOnly) {
-            bool hasArray = false;
-            for (const auto& var : m_vars) {
-                if (var.second->dimension() > 0) {
-                    hasArray = true;
-                    break;
-                }
-            }
-            if (!hasArray) {
-                // Tie each free bit to a fresh random target via a boolean
-                // assumption literal a_k <=> (bit_k == target_k), then force the
-                // bits with (check-sat-assuming ...). If UNSAT,
-                // (get-unsat-assumptions) names the literals clashing with the
-                // feasible base; drop ONE per round so the maximal compatible
-                // set survives -- dropping a whole conflicting group at once
-                // would collapse the diversity of tightly coupled bits (one-hot,
-                // 2-value sets) onto the solver's fixed default. Assumptions are
-                // ephemeral, so rounds need no push/pop or re-asserting and the
-                // solver keeps its learned clauses. Each round drops >= 1 -> ends
-                // in <= npins rounds.
-                std::vector<bool> targets;
-                int npins = 0;
-                for (const auto& var : m_vars) {
-                    const int w = var.second->totalWidth();
-                    for (int b = 0; b < w; b++) {
-                        const bool target = (VL_RANDOM_RNG_I(rngr) & 1);
-                        targets.push_back(target);
-                        os << "(declare-fun a" << npins << " () Bool)\n";
-                        os << "(assert (= a" << npins << " (=";
-                        var.second->emitExtract(os, b);
-                        os << " #b" << (target ? '1' : '0') << ")))\n";
-                        ++npins;
-                    }
-                }
-                std::vector<bool> dropped(npins, false);
-                for (int round = 0; round <= npins; ++round) {
-                    os << "(check-sat-assuming (";
-                    for (int k = 0; k < npins; k++)
-                        if (!dropped[k]) os << " a" << k;
-                    os << "))\n";
-                    if (parseSolution(os, false)) break;
-                    // get-unsat-assumptions only echoes still-active literals,
-                    // so the first in-range index is a live conflicting bit.
-                    const std::vector<int> core = readUnsatAssumptions(os);
-                    for (const int idx : core)
-                        if (idx < npins) {
-                            dropped[idx] = true;
-                            break;
-                        }
-                }
-            } else {
-                // Array present: original XOR-rounds path.
-                for (int i = 0; i < _VL_SOLVER_HASH_LEN_TOTAL && sat; ++i) {
-                    os << "(assert ";
-                    randomConstraint(os, rngr, _VL_SOLVER_HASH_LEN);
-                    os << ")\n";
-                    os << "\n(check-sat)\n";
-                    sat = parseSolution(os, false);
-                    (void)sat;
-                }
-            }
+            solveDiversity(rngr, os);
+            // Check-only must not advance randc cycle state.
+            recordRandcValues();
         }
 
-        // Check-only must not advance randc cycle state.
-        if (!m_checkOnly) recordRandcValues();
-
         os << "(reset)\n";
         return true;
     }
     return false;  // Should not reach here
 }
 
+void VlRandomizer::solveDiversity(VlRNG& rngr, std::iostream& os) {
+    bool hasArray = false;
+    for (const auto& var : m_vars) {
+        if (var.second->dimension() > 0) {
+            hasArray = true;
+            break;
+        }
+    }
+    if (hasArray) {
+        solveDiversityXor(rngr, os);
+    } else {
+        solveDiversityPins(rngr, os);
+    }
+}
+
+void VlRandomizer::solveDiversityPins(VlRNG& rngr, std::iostream& os) {
+    // Tie each free bit to a random target via an assumption literal;
+    // drop one conflicting literal per round until compatible
+    int npins = 0;
+    for (const auto& var : m_vars) {
+        const int w = var.second->totalWidth();
+        for (int b = 0; b < w; ++b) {
+            const bool target = (VL_RANDOM_RNG_I(rngr) & 1);
+            os << "(declare-fun a" << npins << " () Bool)\n";
+            os << "(assert (= a" << npins << " (=";
+            var.second->emitExtract(os, b);
+            os << " #b" << (target ? '1' : '0') << ")))\n";
+            ++npins;
+        }
+    }
+    std::vector<bool> dropped(npins, false);
+    for (int round = 0; round <= npins; ++round) {
+        os << "(check-sat-assuming (";
+        for (int k = 0; k < npins; ++k) {
+            if (!dropped[k]) os << " a" << k;
+        }
+        os << "))\n";
+        if (parseSolution(os)) return;
+        // get-unsat-assumptions only echoes still-active literals,
+        // so the first in-range index is a live conflicting bit.
+        const std::vector<int> core = readUnsatAssumptions(os);
+        for (const int idx : core) {
+            if (idx < npins) {
+                dropped[idx] = true;
+                break;
+            }
+        }
+    }
+}
+
+void VlRandomizer::solveDiversityXor(VlRNG& rngr, std::iostream& os) {
+    bool sat = true;
+    for (int i = 0; i < _VL_SOLVER_HASH_LEN_TOTAL && sat; ++i) {
+        os << "(assert ";
+        randomConstraint(os, rngr, _VL_SOLVER_HASH_LEN);
+        os << ")\n";
+        os << "\n(check-sat)\n";
+        sat = parseSolution(os);
+    }
+}
+
+// False once the solver is gone, so no reply loop can spin forever
+static bool readNonBlankLine(std::istream& is, std::string& liner) {
+    do {
+        if (!std::getline(is, liner)) return false;
+    } while (liner.empty());
+    return true;
+}
+
 bool VlRandomizer::checkSat(std::iostream& os) {
     std::string result;
-    do { std::getline(os, result); } while (result.empty());
+    if (!readNonBlankLine(os, result)) return false;
     return result == "sat";
 }
 
-std::vector<int> VlRandomizer::readUnsatAssumptions(std::iostream& os) {
-    os << "(get-unsat-assumptions)\n";
-    std::string line;
-    do { std::getline(os, line); } while (line.empty());
-    // The response lists only "a<N>" literals; collect each full integer run.
+void VlRandomizer::relaxSoftConstraints(std::iostream& os) {
+    // Re-add softs highest-priority first, dropping incompatible ones.
+    const size_t nSoft = m_softConstraints.size();
+    if (nSoft == 0) return;
+    os << "(push 1)\n";
+    for (const auto& s : m_softConstraints) os << "(assert (= #b1 " << s << "))\n";
+    os << "(check-sat)\n";
+    if (checkSat(os)) return;
+    os << "(pop 1)\n";
+    for (auto it = m_softConstraints.rbegin(); it != m_softConstraints.rend(); ++it) {
+        os << "(push 1)\n";
+        os << "(assert (= #b1 " << *it << "))\n";
+        os << "(check-sat)\n";
+        if (!checkSat(os)) os << "(pop 1)\n";
+    }
+}
+
+// Every complete run of digits in the reply, in order
+static std::vector<int> scanIntRuns(const std::string& reply) {
     std::vector<int> idxs;
     std::string num;
-    for (const char c : line) {
+    for (const char c : reply) {
         if (std::isdigit(static_cast<unsigned char>(c))) {
             num += c;
         } else if (!num.empty()) {
@@ -727,60 +740,66 @@ std::vector<int> VlRandomizer::readUnsatAssumptions(std::iostream& os) {
     return idxs;
 }
 
-bool VlRandomizer::parseSolution(std::iostream& os, bool log) {
-    std::string sat;
-    do { std::getline(os, sat); } while (sat == "");
-    if (sat == "unsat") {
-        if (!log) return false;
-        os << "(get-unsat-core) \n";
-        sat.clear();
-        std::getline(os, sat);
-        std::vector<int> numbers;
-        std::string currentNum;
-        for (const char c : sat) {
-            if (std::isdigit(c)) {
-                currentNum += c;
-                numbers.push_back(std::stoi(currentNum));
-                currentNum.clear();
-            }
-        }
-        if (Verilated::threadContextp()->warnUnsatConstr()) {
-            for (const int n : numbers) {
-                if (n < m_constraints_line.size()) {
-                    const std::string& constraint_info = m_constraints_line[n];
-                    // Parse "filename:linenum   source" format
-                    const size_t colon_pos = constraint_info.find(':');
-                    if (colon_pos != std::string::npos) {
-                        const std::string filename = constraint_info.substr(0, colon_pos);
-                        const size_t space_pos = constraint_info.find("   ", colon_pos);
-                        std::string linenum_str;
-                        std::string source;
-                        if (space_pos != std::string::npos) {
-                            linenum_str
-                                = constraint_info.substr(colon_pos + 1, space_pos - colon_pos - 1);
-                            source = constraint_info.substr(space_pos + 3);
-                        } else {
-                            linenum_str = constraint_info.substr(colon_pos + 1);
-                        }
-                        const int linenum = std::stoi(linenum_str);
-                        std::string msg = "UNSATCONSTR: Unsatisfied constraint";
-                        if (!source.empty()) {
-                            // Trim leading whitespace and add quotes
-                            const size_t start = source.find_first_not_of(" \t");
-                            if (start != std::string::npos) {
-                                msg += ": '" + source.substr(start) + "'";
-                            }
-                        }
-                        VL_WARN_MT(filename.c_str(), linenum, "", msg.c_str());
-                    } else {
-                        VL_PRINTF("%%Warning-UNSATCONSTR: Unsatisfied constraint: %s\n",
-                                  constraint_info.c_str());
-                    }
+std::vector<int> VlRandomizer::readUnsatAssumptions(std::iostream& os) {
+    os << "(get-unsat-assumptions)\n";
+    std::string line;
+    if (!readNonBlankLine(os, line)) return {};
+    // The response lists only "a<N>" literals; collect each full integer run.
+    return scanIntRuns(line);
+}
+
+// Re-solve with named asserts so an unsat core can name the failing constraints
+void VlRandomizer::reportUnsatSetup(std::iostream& os,
+                                    const std::vector<std::string>& uniqueExprs) {
+    os << "(set-option :produce-unsat-cores true)\n";
+    os << "(set-logic QF_ABV)\n";
+    emitDefines(os);
+    emitDeclares(os, false);
+    emitAsserts(os, uniqueExprs, true);
+    os << "(check-sat)\n";
+    std::string status;
+    if (!readNonBlankLine(os, status)) return;
+    if (status == "unsat") reportUnsatCore(os);
+}
+
+void VlRandomizer::reportUnsatCore(std::iostream& os) {
+    os << "(get-unsat-core)\n";
+    std::string reply;
+    std::getline(os, reply);
+    const std::vector<int> numbers = scanIntRuns(reply);
+    if (Verilated::threadContextp()->warnUnsatConstr()) {
+        for (const int n : numbers) {
+            if (static_cast<size_t>(n) < m_constraints_line.size()) {
+                const std::string& constraint_info = m_constraints_line[n];
+                // Parse "filename:linenum   source" format, parts optional
+                std::string filename;
+                int linenum = 0;
+                std::string source = constraint_info;
+                const size_t colon_pos = constraint_info.find(':');
+                if (colon_pos != std::string::npos) {
+                    filename = constraint_info.substr(0, colon_pos);
+                    const size_t space_pos = constraint_info.find("   ", colon_pos);
+                    const size_t num_end
+                        = space_pos == std::string::npos ? constraint_info.size() : space_pos;
+                    linenum = std::atoi(
+                        constraint_info.substr(colon_pos + 1, num_end - colon_pos - 1).c_str());
+                    source = space_pos == std::string::npos
+                                 ? ""
+                                 : constraint_info.substr(space_pos + 3);
                 }
+                std::string msg = "UNSATCONSTR: Unsatisfied constraint";
+                const size_t start = source.find_first_not_of(" \t");
+                if (start != std::string::npos) msg += ": '" + source.substr(start) + "'";
+                VL_WARN_MT(filename.c_str(), linenum, "", msg.c_str());
             }
         }
-        return false;
     }
+}
+
+bool VlRandomizer::parseSolution(std::iostream& os) {
+    std::string sat;
+    if (!readNonBlankLine(os, sat)) return false;
+    if (sat == "unsat") return false;
     if (sat != "sat") {
         std::stringstream msg;
         msg << "Internal: Solver error: " << sat;
@@ -789,25 +808,29 @@ bool VlRandomizer::parseSolution(std::iostream& os, bool log) {
         return false;
     }
 
-    os << "(get-value (";
+    std::stringstream getValueStr;
     for (const auto& var : m_vars) {
         if (var.second->dimension() > 0) {
             auto arrVarsp = std::make_shared<const ArrayInfoMap>(m_arr_vars);
             var.second->setArrayInfo(arrVarsp);
         }
-        var.second->emitGetValue(os);
+        var.second->emitGetValue(getValueStr);
     }
-    os << "))\n";
+    if (getValueStr.str() == "") {
+        // Mark as m_checkOnly to skip generation of any subsequent solver calls
+        m_checkOnly = true;
+        return true;
+    }
+    os << "(get-value (" << getValueStr.str() << "))\n";
     // Quasi-parse S-expression of the form ((x #xVALUE) (y #bVALUE) (z #xVALUE))
     char c;
-    os >> c;
-    if (c != '(') {
+    if (!(os >> c) || c != '(') {
         VL_WARN_MT(__FILE__, __LINE__, "randomize",
                    "Internal: Unable to parse solver's response: invalid S-expression");
         return false;
     }
     while (true) {
-        os >> c;
+        if (!(os >> c)) return false;
         if (c == ')') break;
         if (c != '(') {
             VL_WARN_MT(__FILE__, __LINE__, "randomize",
@@ -912,6 +935,7 @@ void VlRandomizer::clearConstraints() {
     m_constraints_line.clear();
     m_solveBefore.clear();
     m_softConstraints.clear();
+    m_unique_arrays.clear();  // Re-registered by constraint setup
     // Keep m_vars for class member randomization
 }
 
@@ -930,13 +954,7 @@ void VlRandomizer::solveBefore(const std::string& beforeName, const std::string&
     m_solveBefore.emplace_back(beforeName, afterName);
 }
 
-bool VlRandomizer::nextPhased(VlRNG& rngr) {
-    // Phased solving for solve...before constraints.
-    // Variables are solved in layers determined by topological sort of the
-    // solve-before dependency graph. Each layer is solved with ALL constraints
-    // (preserving the solution space) but earlier layers' values are pinned.
-
-    // Step 1: Build dependency graph (before -> {after vars})
+bool VlRandomizer::buildSolveLayers(std::vector<std::vector<std::string>>& layersr) {
     std::map<std::string, std::set<std::string>> graph;
     std::map<std::string, int> inDegree;
     std::set<std::string> solveBeforeVars;
@@ -953,18 +971,12 @@ bool VlRandomizer::nextPhased(VlRNG& rngr) {
         if (inDegree.find(after) == inDegree.end()) inDegree[after] = 0;
     }
 
-    // Compute in-degrees (after depends on before, so edge is before->after,
-    // but for solving order: before has no incoming edge from after)
-    // Actually: "solve x before y" means x should be solved first.
-    // Dependency: y depends on x. Edge: x -> y. in-degree of y increases.
+    // "solve x before y": edge x -> y, in-degree of y increases
     for (const auto& entry : graph) {
         for (const auto& to : entry.second) { inDegree[to]++; }
     }
 
-    // Step 2: Topological sort into layers (Kahn's algorithm)
-    std::vector<std::vector<std::string>> layers;
     std::set<std::string> remaining = solveBeforeVars;
-
     while (!remaining.empty()) {
         std::vector<std::string> currentLayer;
         for (const auto& var : remaining) {
@@ -981,22 +993,38 @@ bool VlRandomizer::nextPhased(VlRNG& rngr) {
                 for (const auto& to : graph[var]) { inDegree[to]--; }
             }
         }
-        layers.push_back(std::move(currentLayer));
+        layersr.push_back(std::move(currentLayer));
     }
+    return true;
+}
 
-    // If only one layer, no phased solving needed -- fall through to normal path
-    // (all solve_before vars are independent, no actual ordering required)
-    if (layers.size() <= 1) {
-        // Clear solve_before temporarily and call normal next()
-        const auto saved = std::move(m_solveBefore);
-        m_solveBefore.clear();
-        const bool result = next(rngr);
-        m_solveBefore = std::move(saved);
-        return result;
+const char* VlRandomizer::phasedLogic() const {
+    for (const auto& var : m_vars) {
+        if (var.second->dimension() == 0) continue;
+        if (!var.second->hasMatchingElements(m_arr_vars, var.second->name())) return "ALL";
     }
+    return "QF_ABV";
+}
 
-    // Step 3: Solve phase by phase
+bool VlRandomizer::nextPhased(VlRNG& rngr, const std::vector<std::string>& uniqueExprs) {
+    // Solve layer by layer with ALL constraints, pinning earlier layers
+    std::vector<std::vector<std::string>> layers;
+    if (!buildSolveLayers(layers)) return false;
+
+    // One layer: all solve_before vars are independent, no ordering required
+    if (layers.size() <= 1) return nextFlat(rngr, uniqueExprs);
+
+    if (solvePhases(rngr, layers, uniqueExprs)) return true;
+    // Retry once with the randc cycle cleared, as nextFlat does
+    if (m_randcUsedValues.empty()) return false;
+    m_randcUsedValues.clear();
+    return solvePhases(rngr, layers, uniqueExprs);
+}
+
+bool VlRandomizer::solvePhases(VlRNG& rngr, const std::vector<std::vector<std::string>>& layers,
+                               const std::vector<std::string>& uniqueExprs) {
     std::map<std::string, std::string> solvedValues;  // varName -> SMT value literal
+    const char* const logicp = phasedLogic();
 
     for (size_t phase = 0; phase < layers.size(); phase++) {
         const bool isFinalPhase = (phase == layers.size() - 1);
@@ -1004,143 +1032,45 @@ bool VlRandomizer::nextPhased(VlRNG& rngr) {
         std::iostream& os = getSolver();
         if (!os) return false;
 
-        // Solver session setup
         os << "(set-option :produce-models true)\n";
-        os << "(set-logic QF_ABV)\n";
-        os << "(define-fun __Vbv ((b Bool)) (_ BitVec 1) (ite b #b1 #b0))\n";
-        os << "(define-fun __Vbool ((v (_ BitVec 1))) Bool (= #b1 v))\n";
+        os << "(set-logic " << logicp << ")\n";
+        emitDefines(os);
+        emitDeclares(os, false);
 
-        // Declare ALL variables
-        for (const auto& var : m_vars) {
-            if (var.second->dimension() > 0) {
-                auto arrVarsp = std::make_shared<const ArrayInfoMap>(m_arr_vars);
-                var.second->setArrayInfo(arrVarsp);
-            }
-            os << "(declare-fun " << var.first << " () ";
-            var.second->emitType(os);
-            os << ")\n";
-        }
-
-        // Pin all previously solved variables
         for (const auto& entry : solvedValues) {
             os << "(assert (= " << entry.first << " " << entry.second << "))\n";
         }
-
-        // Assert ALL constraints
-        for (const std::string& constraint : m_constraints) {
-            os << "(assert (= #b1 " << constraint << "))\n";
-        }
+        emitAsserts(os, uniqueExprs, false);
 
         // Randc: exclude previously used values
         emitRandcExclusions(os);
 
+        // Soft constraints participate in every phase, priority-ordered.
+        relaxSoftConstraints(os);
+
         // Initial check-sat WITHOUT diversity (guaranteed sat if constraints are consistent)
         os << "(check-sat)\n";
 
         if (isFinalPhase) {
             // Final phase: use parseSolution to write ALL values to memory
-            bool sat = parseSolution(os, true);
+            const bool sat = parseSolution(os);
             if (!sat) {
-                if (!m_randcVarNames.empty()) m_randcUsedValues.clear();
                 os << "(reset)\n";
                 return false;
             }
+            solveDiversityXor(rngr, os);
             // Record solved randc values for future exclusion
             recordRandcValues();
-            // Diversity loop (same as normal next())
-            for (int i = 0; i < _VL_SOLVER_HASH_LEN_TOTAL && sat; ++i) {
-                os << "(assert ";
-                randomConstraint(os, rngr, _VL_SOLVER_HASH_LEN);
-                os << ")\n";
-                os << "\n(check-sat)\n";
-                sat = parseSolution(os, false);
-                (void)sat;
-            }
             os << "(reset)\n";
         } else {
-            // Intermediate phase: extract values for current layer variables only
-            std::string satResponse;
-            do { std::getline(os, satResponse); } while (satResponse.empty());
-
-            if (satResponse != "sat") {
+            if (!checkSat(os)) {
                 os << "(reset)\n";
                 return false;
             }
-
-            // Build get-value variable list for this layer
-            const auto& layerVars = layers[phase];
-            auto getValueCmd = [&]() {
-                os << "(get-value (";
-                for (const auto& varName : layerVars) {
-                    if (m_vars.count(varName)) os << varName << " ";
-                }
-                os << "))\n";
-            };
-
-            // Helper to parse ((name1 value1) (name2 value2) ...) response
-            auto parseGetValue = [&]() -> bool {
-                char c;
-                os >> c;  // outer '('
-                while (true) {
-                    os >> c;
-                    if (c == ')') break;  // outer closing
-                    if (c != '(') return false;
-                    std::string name;
-                    os >> name;
-
-                    // Read value handling nested parens for (_ bvN W) format
-                    os >> std::ws;
-                    std::string value;
-                    char firstChar;
-                    os.get(firstChar);
-                    if (firstChar == '(') {
-                        // Compound value like (_ bv5 32)
-                        value = "(";
-                        int depth = 1;
-                        while (depth > 0) {
-                            os.get(c);
-                            value += c;
-                            if (c == '(')
-                                depth++;
-                            else if (c == ')')
-                                depth--;
-                        }
-                        // Read closing ')' of the pair
-                        os >> c;
-                    } else {
-                        // Atom value like #x00000005 or #b101
-                        value += firstChar;
-                        while (os.get(c) && c != ')') { value += c; }
-                        // Trim trailing whitespace
-                        const size_t end = value.find_last_not_of(" \t\n\r");
-                        if (end != std::string::npos) value = value.substr(0, end + 1);
-                    }
-
-                    solvedValues[name] = value;
-                }
-                return true;
-            };
-
-            // Get baseline values (deterministic, always valid)
-            getValueCmd();
-            if (!parseGetValue()) {
+            if (!solvePhaseValues(os, rngr, layers[phase], solvedValues)) {
                 os << "(reset)\n";
                 return false;
             }
-
-            // Try diversity: add random constraint, re-check. If sat, get
-            // updated (more diverse) values. If unsat, keep baseline values.
-            os << "(assert ";
-            randomConstraint(os, rngr, _VL_SOLVER_HASH_LEN);
-            os << ")\n";
-            os << "(check-sat)\n";
-            satResponse.clear();
-            do { std::getline(os, satResponse); } while (satResponse.empty());
-            if (satResponse == "sat") {
-                getValueCmd();
-                parseGetValue();
-            }
-
             os << "(reset)\n";
         }
     }
@@ -1148,6 +1078,86 @@ bool VlRandomizer::nextPhased(VlRNG& rngr) {
     return true;
 }
 
+// Intermediate phase: extract this layer's values, then try one diversity round
+bool VlRandomizer::solvePhaseValues(std::iostream& os, VlRNG& rngr,
+                                    const std::vector<std::string>& layerVars,
+                                    std::map<std::string, std::string>& solvedValuesr) {
+    const auto emitGetValueCmd = [&]() {
+        os << "(get-value (";
+        for (const auto& varName : layerVars) {
+            const auto it = m_vars.find(varName);
+            if (it->second->dimension() > 0) {
+                auto arrVarsp = std::make_shared<const ArrayInfoMap>(m_arr_vars);
+                it->second->setArrayInfo(arrVarsp);
+                // Enumerable arrays: query each element for a QF_ABV-safe pin.
+                if (it->second->hasMatchingElements(m_arr_vars, it->second->name())) {
+                    it->second->emitGetValue(os);
+                    continue;
+                }
+            }
+            os << varName << " ";
+        }
+        os << "))\n";
+    };
+    // Get baseline values (deterministic, always valid)
+    emitGetValueCmd();
+    if (!parsePhaseValues(os, solvedValuesr)) return false;
+
+    // Try diversity: add random constraint, re-check. If sat, get
+    // updated (more diverse) values. If unsat, keep baseline values.
+    os << "(assert ";
+    randomConstraint(os, rngr, _VL_SOLVER_HASH_LEN);
+    os << ")\n";
+    os << "(check-sat)\n";
+    if (checkSat(os)) {
+        emitGetValueCmd();
+        (void)parsePhaseValues(os, solvedValuesr);
+    }
+    return true;
+}
+
+bool VlRandomizer::parsePhaseValues(std::istream& is,
+                                    std::map<std::string, std::string>& solvedValuesr) {
+    // Parse ((name value) ...): one paren-depth counter drives every match.
+    char c = 0;
+    is >> c;  // outer '('
+    if (c != '(') return false;
+    int depth = 1;
+    std::string tokens[2];
+    std::string cur;
+    int fields = 0;
+    const auto flush = [&]() {
+        if (cur.empty()) return;
+        if (fields < 2) tokens[fields] = cur;
+        ++fields;
+        cur.clear();
+    };
+    while (depth > 0 && is.get(c)) {
+        if (c == '(') {
+            ++depth;
+            if (depth >= 3) cur += c;
+        } else if (c == ')') {
+            --depth;
+            if (depth >= 2) {
+                cur += c;
+            } else if (depth == 1) {
+                flush();
+                if (fields == 2) solvedValuesr[tokens[0]] = tokens[1];
+                fields = 0;
+            }
+        } else if (c == ' ' || c == '\t' || c == '\n' || c == '\r') {
+            if (depth >= 3) {
+                cur += c;
+            } else {
+                flush();
+            }
+        } else {
+            cur += c;
+        }
+    }
+    return true;
+}
+
 #ifdef VL_DEBUG
 void VlRandomizer::dump() const {
     for (const auto& var : m_vars) {

include/verilated_random.h

@@ -104,13 +104,32 @@ public:
         count_cache[base_name] = count;
         return count;
     }
+    bool hasMatchingElements(const ArrayInfoMap& arr_vars, const std::string& base_name) const {
+        return arr_vars.find(base_name + "0") != arr_vars.end();
+    }
+};
+// SMT key width per associative-array level (string = 128, integral = 8 * sizeof).
+template <typename T>
+struct VlRandomAssocKeyWidths final {
+    static void push(std::vector<size_t>&) {}
+};
+template <typename T_Key, typename T_Value>
+struct VlRandomAssocKeyWidths<VlAssocArray<T_Key, T_Value>> final {
+    static void push(std::vector<size_t>& widths) {
+        widths.push_back(std::is_same<T_Key, std::string>::value ? 128 : sizeof(T_Key) * 8);
+        VlRandomAssocKeyWidths<T_Value>::push(widths);
+    }
 };
 template <typename T>
 class VlRandomArrayVarTemplate final : public VlRandomVar {
+    // Static key widths per level for the empty-array declaration fallback
+    const std::vector<size_t> m_fallbackIdxWidths;
+
 public:
     VlRandomArrayVarTemplate(const std::string& name, int width, void* datap, int dimension,
-                             std::uint32_t randModeIdx)
-        : VlRandomVar{name, width, datap, dimension, randModeIdx} {}
+                             std::uint32_t randModeIdx, const std::vector<size_t>& idxWidths = {})
+        : VlRandomVar{name, width, datap, dimension, randModeIdx}
+        , m_fallbackIdxWidths{idxWidths} {}
     void* datap(int idx) const override {
         const std::string indexed_name = name() + std::to_string(idx);
         const auto it = m_arrVarsRefp->find(indexed_name);
@@ -175,7 +194,13 @@ public:
             }
         } else {
             if (dimension() > 0) {
-                for (int i = 0; i < dimension(); ++i) s << "(Array (_ BitVec 32) ";
+                // Empty array: declare from the static key widths, not a 32-bit default.
+                for (int i = 0; i < dimension(); ++i) {
+                    const size_t idxWidth = i < static_cast<int>(m_fallbackIdxWidths.size())
+                                                ? m_fallbackIdxWidths[i]
+                                                : 32;
+                    s << "(Array (_ BitVec " << idxWidth << ") ";
+                }
                 s << "(_ BitVec " << width() << ")";
                 for (int i = 0; i < dimension(); ++i) s << ")";
             } else {
@@ -217,8 +242,7 @@ class VlRandomizer VL_NOT_FINAL {
     std::set<std::string> m_disabledVars;  // Variables with rand_mode off (skip write-back)
                                            // variables
     ArrayInfoMap m_arr_vars;  // Tracks each element in array structures for iteration
-    std::vector<std::string> m_unique_arrays;
-    std::map<std::string, uint32_t> m_unique_array_sizes;
+    std::vector<std::string> m_unique_arrays;  // Arrays whose elements must be distinct
     const VlQueue<CData>* m_randmodep = nullptr;  // rand_mode state;
     const VlQueue<CData>* m_static_randmodep = nullptr;  // Static rand_mode state (shared)
     std::unordered_set<std::string> m_staticVars;  // Names of static rand vars
@@ -233,14 +257,37 @@ class VlRandomizer VL_NOT_FINAL {
 
     // PRIVATE METHODS
     void randomConstraint(std::ostream& os, VlRNG& rngr, int bits);
-    bool parseSolution(std::iostream& os, bool log = false);
+    bool parseSolution(std::iostream& os);
     bool checkSat(std::iostream& os);
+    // Assert the maximal compatible soft-constraint set onto the open session.
+    void relaxSoftConstraints(std::iostream& os);
     // Indices of the "a<N>" literals named by (get-unsat-assumptions).
     std::vector<int> readUnsatAssumptions(std::iostream& os);
+    void reportUnsatSetup(std::iostream& os, const std::vector<std::string>& uniqueExprs);
+    void reportUnsatCore(std::iostream& os);
     void emitRandcExclusions(std::ostream& os) const;  // Emit randc exclusion constraints
     void recordRandcValues();  // Record solved randc values for future exclusion
-    size_t hashConstraints() const;
-    bool nextPhased(VlRNG& rngr);  // Phased solving for solve...before
+    size_t hashConstraints(const std::vector<std::string>& extras) const;
+    bool nextRandomize(VlRNG& rngr, bool checkOnly);
+    // "(distinct ...)" expression per unique-constrained array
+    std::vector<std::string> buildUniqueExprs() const;
+    void emitDefines(std::ostream& os) const;
+    void emitDeclares(std::ostream& os, bool pinCurrent) const;
+    void emitAsserts(std::ostream& os, const std::vector<std::string>& extras, bool named) const;
+    bool nextFlat(VlRNG& rngr, const std::vector<std::string>& uniqueExprs);
+    void solveDiversity(VlRNG& rngr, std::iostream& os);
+    void solveDiversityPins(VlRNG& rngr, std::iostream& os);
+    void solveDiversityXor(VlRNG& rngr, std::iostream& os);
+    // Layers of solve...before variables in dependency order
+    bool buildSolveLayers(std::vector<std::vector<std::string>>& layersr);
+    const char* phasedLogic() const;
+    bool nextPhased(VlRNG& rngr, const std::vector<std::string>& uniqueExprs);
+    bool solvePhases(VlRNG& rngr, const std::vector<std::vector<std::string>>& layers,
+                     const std::vector<std::string>& uniqueExprs);
+    bool solvePhaseValues(std::iostream& os, VlRNG& rngr,
+                          const std::vector<std::string>& layerVars,
+                          std::map<std::string, std::string>& solvedValuesr);
+    bool parsePhaseValues(std::istream& is, std::map<std::string, std::string>& solvedValuesr);
 
 public:
     // CONSTRUCTORS
@@ -377,12 +424,12 @@ public:
     }
 
     // Register queue of non-struct types
-    template <typename T>
+    template <typename T, size_t N_MaxSize>
     typename std::enable_if<!VlContainsCustomStruct<T>::value, void>::type
-    write_var(VlQueue<T>& var, int width, const char* name, int dimension,
+    write_var(VlQueue<T, N_MaxSize>& var, int width, const char* name, int dimension,
               std::uint32_t randmodeIdx = std::numeric_limits<std::uint32_t>::max()) {
         if (m_vars.find(name) == m_vars.end()) {
-            m_vars[name] = std::make_shared<const VlRandomArrayVarTemplate<VlQueue<T>>>(
+            m_vars[name] = std::make_shared<const VlRandomArrayVarTemplate<VlQueue<T, N_MaxSize>>>(
                 name, width, &var, dimension, randmodeIdx);
         }
         if (dimension > 0) {
@@ -394,9 +441,9 @@ public:
     }
 
     // Register queue of structs
-    template <typename T>
+    template <typename T, size_t N_MaxSize>
     typename std::enable_if<VlContainsCustomStruct<T>::value, void>::type
-    write_var(VlQueue<T>& var, int width, const char* name, int dimension,
+    write_var(VlQueue<T, N_MaxSize>& var, int width, const char* name, int dimension,
               std::uint32_t randmodeIdx = std::numeric_limits<std::uint32_t>::max()) {
         if (dimension > 0) record_struct_arr(var, name, dimension, {}, {});
     }
@@ -433,9 +480,11 @@ public:
     write_var(VlAssocArray<T_Key, T_Value>& var, int width, const char* name, int dimension,
               std::uint32_t randmodeIdx = std::numeric_limits<std::uint32_t>::max()) {
         if (m_vars.find(name) == m_vars.end()) {
+            std::vector<size_t> keyWidths;
+            VlRandomAssocKeyWidths<VlAssocArray<T_Key, T_Value>>::push(keyWidths);
             m_vars[name]
                 = std::make_shared<const VlRandomArrayVarTemplate<VlAssocArray<T_Key, T_Value>>>(
-                    name, width, &var, dimension, randmodeIdx);
+                    name, width, &var, dimension, randmodeIdx, keyWidths);
         }
         if (dimension > 0) {
             m_index = 0;
@@ -465,11 +514,10 @@ public:
         ++m_index;
     }
 
-    // This is the "Sender" API for the generated code
-    void rand_unique(const std::string& name, uint32_t size) {
-        m_unique_arrays.push_back(name);
-        m_unique_array_sizes[name] = size;
-    }
+    // This is the "Sender" API for the generated code.
+    // The elements to make distinct are taken from the array element table at
+    // solve time, so a container resized by the solver is handled correctly.
+    void rand_unique(const std::string& name) { m_unique_arrays.push_back(name); }
 
     // Recursively record all elements in an unpacked array
     template <typename T, std::size_t N_Depth>
@@ -488,8 +536,8 @@ public:
     }
 
     // Recursively record all elements in a queue
-    template <typename T>
-    void record_arr_table(VlQueue<T>& var, const std::string& name, int dimension,
+    template <typename T, size_t N_MaxSize>
+    void record_arr_table(VlQueue<T, N_MaxSize>& var, const std::string& name, int dimension,
                           std::vector<IData> indices, std::vector<size_t> idxWidths) {
         if ((dimension > 0) && (var.size() != 0)) {
             idxWidths.push_back(32);
@@ -522,7 +570,8 @@ public:
                 idxWidths.push_back(idx_width);
                 indices.insert(indices.end(), integral_index.begin(), integral_index.end());
 
-                record_arr_table(var.at(key), indexed_name, dimension - 1, indices, idxWidths);
+                record_arr_table(var.atWrite(key), indexed_name, dimension - 1, indices,
+                                 idxWidths);
 
                 // Cleanup indices and widths
                 idxWidths.pop_back();
@@ -562,8 +611,8 @@ public:
     }
 
     // Recursively process VlQueue of structs
-    template <typename T>
-    void record_struct_arr(VlQueue<T>& var, const std::string& name, int dimension,
+    template <typename T, size_t N_MaxSize>
+    void record_struct_arr(VlQueue<T, N_MaxSize>& var, const std::string& name, int dimension,
                            std::vector<IData> indices, std::vector<size_t> idxWidths) {
         if ((dimension > 0) && (var.size() != 0)) {
             idxWidths.push_back(32);
@@ -596,7 +645,7 @@ public:
 
                 std::string result = oss.str();
                 result.insert(result.begin(), int(idx_width / 4) - result.size(), '0');
-                record_struct_arr(var.at(key), name + "." + result, dimension - 1, indices,
+                record_struct_arr(var.atWrite(key), name + "." + result, dimension - 1, indices,
                                   idxWidths);
             }
         }
@@ -724,11 +773,20 @@ public:
     bool basicStdRandomization(VlAssocArray<T_Key, T_Value>& value, size_t width) {
         T_Key key;
         for (int exists = value.first(key); exists; exists = value.next(key)) {
-            basicStdRandomization(value.at(key), width);
+            basicStdRandomization(value.atWrite(key), width);
         }
         return true;
     }
     bool next() { return VlRandomizer::next(m_rng); }
 };
 
+//======================================================================
+//Helper method for dynamic array handling in SMT expressions
+
+inline std::string vlToSolverHex(const IData& value) {
+    std::ostringstream oss;
+    oss << std::hex << std::setfill('0') << std::setw(8) << value;
+    return oss.str();
+}
+
 #endif  // Guard

include/verilated_save.h

@@ -327,7 +327,7 @@ VerilatedDeserialize& operator>>(VerilatedDeserialize& os, VlAssocArray<T_Key, T
         T_Value value;
         os >> index;
         os >> value;
-        rhs.at(index) = value;
+        rhs.atWrite(index) = value;
     }
     return os;
 }

include/verilated_trace_imp.h

@@ -449,7 +449,7 @@ void VerilatedTrace<VL_SUB_T, VL_BUF_T>::initLib(const std::string& name) VL_MT_
 // All of these take a destination pointer where the string will be emitted,
 // and a value to convert. There are a couple of variants for efficiency.
 
-static inline void cvtCDataToStr(char* dstp, CData value) {
+inline void cvtCDataToStr(char* dstp, CData value) {
 #ifdef VL_HAVE_SSE2
     // Similar to cvtSDataToStr but only the bottom 8 byte lanes are used
     const __m128i a = _mm_cvtsi32_si128(value);
@@ -471,7 +471,7 @@ static inline void cvtCDataToStr(char* dstp, CData value) {
 #endif
 }
 
-static inline void cvtSDataToStr(char* dstp, SData value) {
+inline void cvtSDataToStr(char* dstp, SData value) {
 #ifdef VL_HAVE_SSE2
     // We want each bit in the 16-bit input value to end up in a byte lane
     // within the 128-bit XMM register. Note that x86 is little-endian and we
@@ -507,7 +507,7 @@ static inline void cvtSDataToStr(char* dstp, SData value) {
 #endif
 }
 
-static inline void cvtIDataToStr(char* dstp, IData value) {
+inline void cvtIDataToStr(char* dstp, IData value) {
 #ifdef VL_HAVE_AVX2
     // Similar to cvtSDataToStr but the bottom 16-bits are processed in the
     // top half of the YMM registers
@@ -526,7 +526,7 @@ static inline void cvtIDataToStr(char* dstp, IData value) {
 #endif
 }
 
-static inline void cvtQDataToStr(char* dstp, QData value) {
+inline void cvtQDataToStr(char* dstp, QData value) {
     cvtIDataToStr(dstp, value >> 32);
     cvtIDataToStr(dstp + 32, value);
 }

include/verilated_types.h

@@ -214,7 +214,7 @@ public:
 };
 static_assert(sizeof(WDataInP) == sizeof(EData*), "WDataInP should be a single pointer");
 
-static int _vl_cmp_w(int words, WDataInP const lwp, WDataInP const rwp) VL_PURE;
+inline int _vl_cmp_w(int words, WDataInP const lwp, WDataInP const rwp) VL_PURE;
 
 template <std::size_t N_Words>
 bool VlWide<N_Words>::operator<(const VlWide<N_Words>& rhs) const VL_PURE {
@@ -337,6 +337,7 @@ public:
 
     ~VlProcess() {
         if (m_parentp) m_parentp->detach(this);
+        if (t_currentp == this) t_currentp = m_parentp.get();
     }
 
     void attach(VlProcess* childp) { m_children.insert(childp); }
@@ -931,7 +932,7 @@ public:
     VlQueue min(T_Func with_func) const {
         if (m_deque.empty()) return VlQueue{};
         const auto it = std::min_element(m_deque.cbegin(), m_deque.cend(),
-                                         [&with_func](const IData& a, const IData& b) {
+                                         [&with_func](const T_Value& a, const T_Value& b) {
                                              return with_func(0, a) < with_func(0, b);
                                          });
         return VlQueue::consV(*it);
@@ -945,7 +946,7 @@ public:
     VlQueue max(T_Func with_func) const {
         if (m_deque.empty()) return VlQueue{};
         const auto it = std::max_element(m_deque.cbegin(), m_deque.cend(),
-                                         [&with_func](const IData& a, const IData& b) {
+                                         [&with_func](const T_Value& a, const T_Value& b) {
                                              return with_func(0, a) < with_func(0, b);
                                          });
         return VlQueue::consV(*it);
@@ -1119,9 +1120,7 @@ public:
         return 1;
     }
     // Setting. Verilog: assoc[index] = v
-    // Can't just overload operator[] or provide a "at" reference to set,
-    // because we need to be able to insert only when the value is set
-    T_Value& at(const T_Key& index) {
+    T_Value& atWrite(const T_Key& index) {
         const auto it = m_map.find(index);
         if (it == m_map.end()) {
             std::pair<typename Map::iterator, bool> pit = m_map.emplace(index, m_defaultValue);
@@ -1137,7 +1136,7 @@ public:
     }
     // Setting as a chained operation
     VlAssocArray& set(const T_Key& index, const T_Value& value) {
-        at(index) = value;
+        atWrite(index) = value;
         return *this;
     }
     VlAssocArray& setDefault(const T_Value& value) {
@@ -1394,7 +1393,7 @@ void VL_READMEM_N(bool hex, int bits, const std::string& filename,
         QData addr;
         std::string data;
         if (rmem.get(addr /*ref*/, data /*ref*/)) {
-            rmem.setData(&(obj.at(addr)), data);
+            rmem.setData(&(obj.atWrite(addr)), data);
         } else {
             break;
         }
@@ -2069,8 +2068,24 @@ struct VlNull final {
     operator T*() const {
         return nullptr;
     }
+    template <class T>
+    bool operator==(T* rhs) const {
+        return !rhs;
+    }
+    template <class T>
+    bool operator==(const T* rhs) const {
+        return !rhs;
+    }
 };
-inline bool operator==(const void* ptr, VlNull) { return !ptr; }
+
+template <class T>
+inline bool operator==(T* lhs, VlNull) {
+    return !lhs;
+}
+template <class T>
+inline bool operator==(const T* lhs, VlNull) {
+    return !lhs;
+}
 
 //===================================================================
 // Verilog class reference container
@@ -2223,7 +2238,7 @@ public:
 };
 
 template <typename T_Lhs, typename T_Out>
-static inline bool VL_CAST_DYNAMIC(VlClassRef<T_Lhs> in, VlClassRef<T_Out>& outr) {
+inline bool VL_CAST_DYNAMIC(VlClassRef<T_Lhs> in, VlClassRef<T_Out>& outr) {
     if (!in) {
         outr = VlNull{};
         return true;
@@ -2237,7 +2252,7 @@ static inline bool VL_CAST_DYNAMIC(VlClassRef<T_Lhs> in, VlClassRef<T_Out>& outr
 }
 
 template <typename T_Lhs>
-static inline bool VL_CAST_DYNAMIC(VlNull, VlClassRef<T_Lhs>& outr) {
+inline bool VL_CAST_DYNAMIC(VlNull, VlClassRef<T_Lhs>& outr) {
     outr = VlNull{};
     return true;
 }

include/verilated_vpi.cpp

@@ -539,7 +539,7 @@ public:
         for (auto idx : index()) m_fullname += "[" + std::to_string(idx) + "]";
         return m_fullname.c_str();
     }
-    void* prevDatap() const { return m_prevDatap; }
+    uint8_t* prevDatap() const { return m_prevDatap; }
     void* varDatap() const override { return m_varDatap; }
     void createPrevDatap() {
         if (VL_UNLIKELY(!m_prevDatap)) {
@@ -1027,6 +1027,26 @@ struct VerilatedVpiTimedCbsCmp final {
 class VerilatedVpiError;
 void vl_vpi_put_word(const VerilatedVpioVar* vop, QData word, size_t bitCount, size_t addOffset);
 
+// Information about how to access packed array data.
+// If underlying type is multi-word (VLVT_WDATA), the packed element might straddle word
+// boundaries, in which case m_maskHi != 0.
+template <typename T>
+struct VarAccessInfo final {
+    T* m_datap;  // Typed pointer to packed array base address
+    size_t m_bitOffset;  // Data start location (bit offset)
+    size_t m_wordOffset;  // Data start location (word offset, VLVT_WDATA only)
+    T m_maskLo;  // Access mask for m_datap[m_wordOffset]
+    T m_maskHi;  // Access mask for m_datap[m_wordOffset + 1] (VLVT_WDATA only)
+};
+template <typename T>
+VarAccessInfo<T> vl_vpi_var_access_info(const VerilatedVpioVarBase* vop, size_t bitCount,
+                                        size_t addOffset);
+template <typename T>
+T vl_vpi_get_word_gen(VarAccessInfo<T> info);
+
+template <typename T>
+void vl_vpi_put_word_gen(VarAccessInfo<T> info, T word);
+
 class VerilatedVpiImp final {
     enum { CB_ENUM_MAX_VALUE = cbAtEndOfSimTime + 1 };  // Maximum callback reason
     using VpioCbList = std::list<VerilatedVpiCbHolder>;
@@ -1169,6 +1189,72 @@ public:
         s().m_cbCallList.clear();
         return called;
     }
+    template <typename T>
+    static bool valueDiffersFromPrev(VerilatedVpioVar* varop) {
+        VL_DEBUG_IF_PLI(VL_DBG_MSGF("- vpi: value_test %s v[0]=%d/%d %p %p size=%d\n",
+                                    varop->fullname(), *(static_cast<CData*>(varop->varDatap())),
+                                    *(varop->prevDatap()), varop->varDatap(), varop->prevDatap(),
+                                    varop->entSize()););
+        if (varop->bitSize() == 1) {
+            T* const prevDatap = reinterpret_cast<T*>(
+                varop->prevDatap());  // Was malloced when we added the callback
+            const VarAccessInfo<T> currInfo
+                = vl_vpi_var_access_info<T>(varop, varop->bitSize(), 0);
+            VarAccessInfo<T> prevInfo = currInfo;
+            prevInfo.m_datap = prevDatap;
+            return vl_vpi_get_word_gen(currInfo) != vl_vpi_get_word_gen(prevInfo);
+        }
+        return std::memcmp(varop->prevDatap(), varop->varDatap(), varop->entSize()) != 0;
+    }
+    static bool valueDiffersFromPrev(VerilatedVpioVar* varop) {
+        switch (varop->varp()->vltype()) {
+        case VLVT_UINT8: return valueDiffersFromPrev<CData>(varop);
+        case VLVT_UINT16: return valueDiffersFromPrev<SData>(varop);
+        case VLVT_UINT32: return valueDiffersFromPrev<IData>(varop);
+        case VLVT_UINT64: return valueDiffersFromPrev<QData>(varop);
+        case VLVT_WDATA:
+            return valueDiffersFromPrev<EData>(varop);
+            // LCOV_EXCL_START - Would require earlier type check to not catch that
+        default:
+            const std::string msg
+                = "Unsupported type (" + std::to_string(varop->varp()->vltype()) + ")";
+            VL_FATAL_MT(__FILE__, __LINE__, "", msg.c_str());
+            return true;
+            // LCOV_EXCL_STOP
+        }
+    }
+    template <typename T>
+    static void updatePrev(const VerilatedVpioVar* const varop) {
+        if (varop->bitSize() == 1) {
+            const VarAccessInfo<T> currInfo
+                = vl_vpi_var_access_info<T>(varop, varop->bitSize(), 0);
+            VarAccessInfo<T> prevInfo = currInfo;
+            T* const prevDatap = reinterpret_cast<T*>(varop->prevDatap());
+            prevInfo.m_datap = prevDatap;
+            const T currWord = vl_vpi_get_word_gen(currInfo);
+            vl_vpi_put_word_gen(prevInfo, currWord);
+            assert(std::memcmp(varop->prevDatap(), varop->varDatap(), varop->entSize()) == 0);
+        } else {
+            std::memcpy(varop->prevDatap(), varop->varDatap(), varop->entSize());
+        }
+    }
+    static void updatePrev(const VerilatedVpioVar* const varop) {
+        switch (varop->varp()->vltype()) {
+        case VLVT_UINT8: updatePrev<CData>(varop); break;
+        case VLVT_UINT16: updatePrev<SData>(varop); break;
+        case VLVT_UINT32: updatePrev<IData>(varop); break;
+        case VLVT_UINT64: updatePrev<QData>(varop); break;
+        case VLVT_WDATA:
+            updatePrev<EData>(varop);
+            break;
+            // LCOV_EXCL_START - Would require earlier type check to not catch that
+        default:
+            const std::string msg
+                = "Unsupported type (" + std::to_string(varop->varp()->vltype()) + ")";
+            VL_FATAL_MT(__FILE__, __LINE__, "", msg.c_str());
+            // LCOV_EXCL_STOP
+        }
+    }
     static bool callValueCbs() VL_MT_UNSAFE_ONE {
         assertOneCheck();
         VpioCbList& cbObjList = s().m_cbCurrentLists[cbValueChange];
@@ -1187,15 +1273,10 @@ public:
             VerilatedVpiCbHolder& ho = *it++;
             VerilatedVpioVar* const varop
                 = reinterpret_cast<VerilatedVpioVar*>(ho.cb_datap()->obj);
-            void* const newDatap = varop->varDatap();
-            void* const prevDatap = varop->prevDatap();  // Was malloced when we added the callback
-            VL_DEBUG_IF_PLI(VL_DBG_MSGF("- vpi: value_test %s v[0]=%d/%d %p %p\n",
-                                        varop->fullname(), *(static_cast<CData*>(newDatap)),
-                                        *(static_cast<CData*>(prevDatap)), newDatap, prevDatap););
-            if (std::memcmp(prevDatap, newDatap, varop->entSize()) != 0) {
+            if (valueDiffersFromPrev(varop)) {
                 VL_DEBUG_IF_PLI(VL_DBG_MSGF("- vpi: value_callback %" PRId64 " %s v[0]=%d\n",
                                             ho.id(), varop->fullname(),
-                                            *(static_cast<CData*>(newDatap))););
+                                            *(static_cast<CData*>(varop->varDatap()))););
                 update.insert(varop);
                 vpi_get_value(ho.cb_datap()->obj, ho.cb_datap()->value);
                 (ho.cb_rtnp())(ho.cb_datap());
@@ -1203,9 +1284,7 @@ public:
             }
             if (was_last) break;
         }
-        for (const VerilatedVpioVar* const ip : update) {
-            std::memcpy(ip->prevDatap(), ip->varDatap(), ip->entSize());
-        }
+        for (const VerilatedVpioVar* const varop : update) updatePrev(varop);
         return called;
     }
     static void dumpCbs() VL_MT_UNSAFE_ONE;
@@ -2410,7 +2489,7 @@ vpiHandle vpi_register_cb(p_cb_data cb_data_p) {
         return vop->castVpiHandle();
     }
     default:
-        VL_VPI_WARNING_(__FILE__, __LINE__, "%s: Unsupported callback type %s", __func__,
+        VL_VPI_WARNING_(__FILE__, __LINE__, "%s: Unsupported callback type '%s'", __func__,
                         VerilatedVpiError::strFromVpiCallbackReason(reason));
         return nullptr;
     }
@@ -2856,7 +2935,7 @@ vpiHandle vpi_handle(PLI_INT32 type, vpiHandle object) {
             return (new VerilatedVpioConst{vop->rangep()->left()})->castVpiHandle();
         }
         VL_VPI_WARNING_(__FILE__, __LINE__,
-                        "%s: Unsupported vpiHandle (%p) for type %s, nothing will be returned",
+                        "%s: Unsupported vpiHandle '%p' for type '%s', nothing will be returned",
                         __func__, object, VerilatedVpiError::strFromVpiMethod(type));
         return nullptr;
     }
@@ -2870,7 +2949,7 @@ vpiHandle vpi_handle(PLI_INT32 type, vpiHandle object) {
             return (new VerilatedVpioConst{vop->rangep()->right()})->castVpiHandle();
         }
         VL_VPI_WARNING_(__FILE__, __LINE__,
-                        "%s: Unsupported vpiHandle (%p) for type %s, nothing will be returned",
+                        "%s: Unsupported vpiHandle '%p' for type '%s', nothing will be returned",
                         __func__, object, VerilatedVpiError::strFromVpiMethod(type));
         return nullptr;
     }
@@ -3031,8 +3110,9 @@ PLI_INT32 vpi_get(PLI_INT32 property, vpiHandle object) {
         [[fallthrough]];
     }
     default:
-        VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported property %s, nothing will be returned",
-                      __func__, VerilatedVpiError::strFromVpiProp(property));
+        VL_VPI_ERROR_(__FILE__, __LINE__,
+                      "%s: Unsupported property '%s', nothing will be returned", __func__,
+                      VerilatedVpiError::strFromVpiProp(property));
         return vpiUndefined;
     }
 }
@@ -3195,18 +3275,6 @@ static void vl_strprintf(std::string& buffer, char const* fmt, ...) {
     va_end(args);
 }
 
-// Information about how to access packed array data.
-// If underlying type is multi-word (VLVT_WDATA), the packed element might straddle word
-// boundaries, in which case m_maskHi != 0.
-template <typename T>
-struct VarAccessInfo final {
-    T* m_datap;  // Typed pointer to packed array base address
-    size_t m_bitOffset;  // Data start location (bit offset)
-    size_t m_wordOffset;  // Data start location (word offset, VLVT_WDATA only)
-    T m_maskLo;  // Access mask for m_datap[m_wordOffset]
-    T m_maskHi;  // Access mask for m_datap[m_wordOffset + 1] (VLVT_WDATA only)
-};
-
 template <typename T>
 VarAccessInfo<T> vl_vpi_var_access_info(const VerilatedVpioVarBase* vop, size_t bitCount,
                                         size_t addOffset) {
@@ -3262,21 +3330,25 @@ VarAccessInfo<T> vl_vpi_var_access_info(const VerilatedVpioVarBase* vop, size_t
 }
 
 template <typename T>
-T vl_vpi_get_word_gen(const VerilatedVpioVarBase* vop, size_t bitCount, size_t addOffset) {
+T vl_vpi_get_word_gen(VarAccessInfo<T> info) {
     const size_t wordBits = sizeof(T) * 8;
-    const VarAccessInfo<T> info = vl_vpi_var_access_info<T>(vop, bitCount, addOffset);
-    if (info.m_maskHi)
+    if (info.m_maskHi) {
         return ((info.m_datap[info.m_wordOffset] & info.m_maskLo) >> info.m_bitOffset)
                | ((info.m_datap[info.m_wordOffset + 1] & info.m_maskHi)
                   << (wordBits - info.m_bitOffset));
+    }
     return (info.m_datap[info.m_wordOffset] & info.m_maskLo) >> info.m_bitOffset;
 }
 
 template <typename T>
-void vl_vpi_put_word_gen(const VerilatedVpioVar* vop, T word, size_t bitCount, size_t addOffset) {
-    const size_t wordBits = sizeof(T) * 8;
+T vl_vpi_get_word_gen(const VerilatedVpioVarBase* vop, size_t bitCount, size_t addOffset) {
     const VarAccessInfo<T> info = vl_vpi_var_access_info<T>(vop, bitCount, addOffset);
+    return vl_vpi_get_word_gen(info);
+}
 
+template <typename T>
+void vl_vpi_put_word_gen(VarAccessInfo<T> info, T word) {
+    const size_t wordBits = sizeof(T) * 8;
     if (info.m_maskHi) {
         info.m_datap[info.m_wordOffset + 1]
             = (info.m_datap[info.m_wordOffset + 1] & ~info.m_maskHi)
@@ -3287,6 +3359,12 @@ void vl_vpi_put_word_gen(const VerilatedVpioVar* vop, T word, size_t bitCount, s
                                       | ((word << info.m_bitOffset) & info.m_maskLo);
 }
 
+template <typename T>
+void vl_vpi_put_word_gen(const VerilatedVpioVar* vop, T word, size_t bitCount, size_t addOffset) {
+    const VarAccessInfo<T> info = vl_vpi_var_access_info<T>(vop, bitCount, addOffset);
+    vl_vpi_put_word_gen(info, word);
+}
+
 // bitCount: maximum number of bits to read, will stop earlier if it reaches the var bounds
 // addOffset: additional read bitoffset
 QData vl_vpi_get_word(const VerilatedVpioVarBase* vop, size_t bitCount, size_t addOffset) {
@@ -3500,7 +3578,7 @@ void vpi_get_value(vpiHandle object, p_vpi_value valuep) {
                       VerilatedVpiError::strFromVpiVal(valuep->format), vop->fullname());
         return;
     }
-    VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported vpiHandle (%p)", __func__, object);
+    VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported vpiHandle '%p'", __func__, object);
 }
 
 vpiHandle vpi_put_value(vpiHandle object, p_vpi_value valuep, p_vpi_time /*time_p*/,
@@ -3841,7 +3919,7 @@ vpiHandle vpi_put_value(vpiHandle object, p_vpi_value valuep, p_vpi_time /*time_
                         __func__, vop->fullname());
         return nullptr;
     }
-    VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported vpiHandle (%p)", __func__, object);
+    VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported vpiHandle '%p'", __func__, object);
     return nullptr;
 }
 
@@ -4236,13 +4314,13 @@ void vpi_get_value_array(vpiHandle object, p_vpi_arrayvalue arrayvalue_p, PLI_IN
 
     const VerilatedVpioVar* const vop = VerilatedVpioVar::castp(object);
     if (VL_UNLIKELY(!vop)) {
-        VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported vpiHandle (%p)", __func__, object);
+        VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported vpiHandle '%p'", __func__, object);
         return;
     }
 
     if (vop->type() != vpiRegArray) {
-        VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported type (%p, %s)", __func__, object,
-                      VerilatedVpiError::strFromVpiObjType(vop->type()));
+        VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported type '%s' for '%s'", __func__,
+                      VerilatedVpiError::strFromVpiObjType(vop->type()), vop->name());
         return;
     }
 
@@ -4418,13 +4496,13 @@ void vpi_put_value_array(vpiHandle object, p_vpi_arrayvalue arrayvalue_p, PLI_IN
 
     const VerilatedVpioVar* const vop = VerilatedVpioVar::castp(object);
     if (VL_UNLIKELY(!vop)) {
-        VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported vpiHandle (%p)", __func__, object);
+        VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported vpiHandle '%p'", __func__, object);
         return;
     }
 
     if (vop->type() != vpiRegArray) {
-        VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported type (%p, %s)", __func__, object,
-                      VerilatedVpiError::strFromVpiObjType(vop->type()));
+        VL_VPI_ERROR_(__FILE__, __LINE__, "%s: Unsupported vpiHandle type '%s' for '%s'", __func__,
+                      VerilatedVpiError::strFromVpiObjType(vop->type()), vop->name());
         return;
     }
 

include/verilatedos.h

@@ -332,10 +332,19 @@
 
 #ifdef VL_GCOV
 extern "C" void __gcov_dump();
+extern "C" void __gcov_reset();
 // Dump internal code coverage data before e.g. std::abort()
 # define VL_GCOV_DUMP() __gcov_dump()
+// Dump, then re-arm dumping; dumping is one-shot, so without the reset a dump
+// on a nonfatal path would silently discard everything counted after it
+# define VL_GCOV_DUMP_RESET() \
+        do { \
+            __gcov_dump(); \
+            __gcov_reset(); \
+        } while (false)
 #else
 # define VL_GCOV_DUMP()
+# define VL_GCOV_DUMP_RESET()
 #endif
 
 //=========================================================================
@@ -368,6 +377,7 @@ extern "C" void __gcov_dump();
 #define __STDC_FORMAT_MACROS
 
 // Now that C++ requires these standard types the vl types are deprecated
+#include <cstddef>  // offsetof (used by generated VlVarTableEntry tables)
 #include <cstdint>
 #include <cinttypes>
 #include <cmath>
@@ -460,6 +470,7 @@ using ssize_t = uint32_t;  ///< signed size_t; returned from read()
 // Integer size macros
 
 #define VL_BYTESIZE 8  ///< Bits in a CData / byte
+#define VL_BYTESIZE_LOG2 3  ///< log2(VL_BYTESIZE)
 #define VL_SHORTSIZE 16  ///< Bits in a SData / short
 #define VL_IDATASIZE 32  ///< Bits in an IData / word
 #define VL_QUADSIZE 64  ///< Bits in a QData / quadword
@@ -472,9 +483,9 @@ using ssize_t = uint32_t;  ///< signed size_t; returned from read()
 #endif
 
 /// Return number of bytes argument-number of bits needs (1 bit=1 byte)
-#define VL_BYTES_I(nbits) (((nbits) + (VL_BYTESIZE - 1)) / VL_BYTESIZE)
+#define VL_BYTES_I(nbits) (((nbits) + (VL_BYTESIZE - 1)) >> VL_BYTESIZE_LOG2)
 /// Return Words/EDatas in argument-number of bits needs (1 bit=1 word)
-#define VL_WORDS_I(nbits) (((nbits) + (VL_EDATASIZE - 1)) / VL_EDATASIZE)
+#define VL_WORDS_I(nbits) (((nbits) + (VL_EDATASIZE - 1)) >> VL_EDATASIZE_LOG2)
 // Number of Words/EDatas a quad requires
 #define VL_WQ_WORDS_E VL_WORDS_I(VL_QUADSIZE)
 
@@ -536,10 +547,10 @@ using ssize_t = uint32_t;  ///< signed size_t; returned from read()
 // #defines, to avoid requiring math.h on all compile runs
 
 #ifdef _MSC_VER
-static inline double VL_TRUNC(double n) {
+inline double VL_TRUNC(double n) {
     return (n < 0) ? std::ceil(n) : std::floor(n);
 }
-static inline double VL_ROUND(double n) {
+inline double VL_ROUND(double n) {
     return (n < 0) ? std::ceil(n-0.5) : std::floor(n + 0.5);
 }
 #else

include/verilatedos_c.h

@@ -169,17 +169,19 @@ void memUsageBytes(uint64_t& peakr, uint64_t& currentr) VL_MT_SAFE {
     }
 #else
     // Highly unportable. Sorry
+    // Use VmHWM (peak resident), matching Windows PeakWorkingSetSize and macOS resident_size_max.
+    // VmHWM excludes pages swapped out before the peak; /proc has no peak-(RSS+Swap) counter.
     std::ifstream is{"/proc/self/status"};
     if (!is) return;
     std::string line;
-    uint64_t vmPeak = 0;
+    uint64_t vmHwm = 0;
     uint64_t vmRss = 0;
     uint64_t vmSwap = 0;
     std::string field;
     while (std::getline(is, line)) {
-        if (line.rfind("VmPeak:", 0) == 0) {
+        if (line.rfind("VmHWM:", 0) == 0) {
             std::stringstream ss{line};
-            ss >> field >> vmPeak;
+            ss >> field >> vmHwm;
         } else if (line.rfind("VmRSS:", 0) == 0) {
             std::stringstream ss{line};
             ss >> field >> vmRss;
@@ -188,7 +190,7 @@ void memUsageBytes(uint64_t& peakr, uint64_t& currentr) VL_MT_SAFE {
             ss >> field >> vmSwap;
         }
     }
-    peakr = vmPeak * 1024;
+    peakr = vmHwm * 1024;
     currentr = (vmRss + vmSwap) * 1024;
 #endif
 }

nodist/verilog_format

@@ -12,6 +12,8 @@
 # SPDX-FileCopyrightText: 2026 Wilson Snyder
 # SPDX-License-Identifier: CC0-1.0
 
+# These flags tested against verible-v0.0-4080-ga0a8d8eb
+
 verible-verilog-format \
     --inplace \
     --wrap_end_else_clauses  \

python-dev-requirements.txt

@@ -33,4 +33,4 @@ sphinxcontrib-spelling==8.0.2
 yamlfix==1.19.1
 yapf==0.43.0
 
-git+https://github.com/antmicro/astsee.git
+git+https://github.com/antmicro/astsee.git@222480a8ec13b312809ea4acc08c81b4c0f4da2f

src/CMakeLists.txt

@@ -149,6 +149,7 @@ set(HEADERS
     V3OrderGraph.h
     V3OrderInternal.h
     V3OrderMoveGraph.h
+    V3OrderMTaskGraph.h
     V3Os.h
     V3PairingHeap.h
     V3Param.h
@@ -156,6 +157,7 @@ set(HEADERS
     V3ParseImp.h
     V3PchAstMT.h
     V3PchAstNoMT.h
+    V3PoolAllocator.h
     V3PreExpr.h
     V3PreLex.h
     V3PreProc.h
@@ -170,7 +172,6 @@ set(HEADERS
     V3Sampled.h
     V3Sched.h
     V3Scope.h
-    V3Scoreboard.h
     V3SenExprBuilder.h
     V3SenTree.h
     V3Simulate.h
@@ -319,6 +320,9 @@ set(COMMON_SOURCES
     V3Order.cpp
     V3OrderGraphBuilder.cpp
     V3OrderMoveGraph.cpp
+    V3OrderMTaskContraction.cpp
+    V3OrderMTaskFixHazards.cpp
+    V3OrderMTaskGraph.cpp
     V3OrderParallel.cpp
     V3OrderProcessDomains.cpp
     V3OrderSerial.cpp
@@ -346,7 +350,6 @@ set(COMMON_SOURCES
     V3SchedUtil.cpp
     V3SchedVirtIface.cpp
     V3Scope.cpp
-    V3Scoreboard.cpp
     V3Slice.cpp
     V3Split.cpp
     V3SplitVar.cpp

src/Makefile_obj.in

@@ -309,6 +309,9 @@ RAW_OBJS_PCH_ASTNOMT = \
   V3Order.o \
   V3OrderGraphBuilder.o \
   V3OrderMoveGraph.o \
+  V3OrderMTaskContraction.o \
+  V3OrderMTaskFixHazards.o \
+  V3OrderMTaskGraph.o \
   V3OrderParallel.o \
   V3OrderProcessDomains.o \
   V3OrderSerial.o \
@@ -330,7 +333,6 @@ RAW_OBJS_PCH_ASTNOMT = \
   V3SchedUtil.o \
   V3SchedVirtIface.o \
   V3Scope.o \
-  V3Scoreboard.o \
   V3Slice.o \
   V3Split.o \
   V3SplitVar.o \

src/V3ActiveTop.cpp

@@ -36,11 +36,13 @@ VL_DEFINE_DEBUG_FUNCTIONS;
 // Active class functions
 
 class ActiveTopVisitor final : public VNVisitor {
+    // NODE STATE
+    // AstVarScope::user1()  // bool.  Processed
+
     // STATE
     SenTreeFinder m_finder;  // Find global sentree's / add them under the AstTopScope
 
     // METHODS
-
     static bool isInitial(AstNode* nodep) {
         const VNUser1InUse user1InUse;
         // Return true if no variables that read.

src/V3Assert.cpp

@@ -20,6 +20,7 @@
 
 #include "V3AstUserAllocator.h"
 #include "V3Stats.h"
+#include "V3UniqueNames.h"
 
 VL_DEFINE_DEBUG_FUNCTIONS;
 
@@ -89,6 +90,58 @@ public:
     explicit DefaultDisablePropagateVisitor(AstNetlist* nodep) { iterate(nodep); }
 };
 
+// Lower a sequence used as an event control ('@seq', IEEE 1800-2023 9.4.2.4) into a
+// synthesized event fired by an internal 'cover sequence' on each end-of-match
+class SeqEventLowerVisitor final : public VNVisitor {
+    // STATE
+    AstNodeModule* m_modp = nullptr;  // Current module
+    V3UniqueNames m_names{"__VseqEvent"};  // Synthesized event names
+
+    // VISITORS
+    void visit(AstNodeModule* nodep) override {
+        VL_RESTORER(m_modp);
+        m_modp = nodep;
+        iterateChildren(nodep);
+    }
+    void visit(AstSenItem* nodep) override {
+        AstFuncRef* const funcrefp = VN_CAST(nodep->sensp(), FuncRef);
+        if (funcrefp && VN_IS(funcrefp->taskp(), Sequence)) {
+            FileLine* const flp = nodep->fileline();
+            AstVar* const eventp = new AstVar{flp, VVarType::MODULETEMP, m_names.get(nodep),
+                                              m_modp->findBasicDType(VBasicDTypeKwd::EVENT)};
+            eventp->lifetime(VLifetime::STATIC_EXPLICIT);
+            m_modp->addStmtsp(eventp);
+            v3Global.setHasEvents();
+            funcrefp->unlinkFrBack();
+            nodep->sensp(new AstVarRef{flp, eventp, VAccess::READ});
+            const bool automaticActual = funcrefp->exists([](const AstNodeVarRef* refp) {
+                return refp->varp() && refp->varp()->lifetime().isAutomatic();
+            });
+            if (automaticActual) {
+                nodep->v3error("Arguments to a sequence used as an event control must be"
+                               " static (IEEE 1800-2023 9.4.2.4)");
+                VN_AS(funcrefp->taskp(), Sequence)->isReferenced(false);
+                VL_DO_DANGLING(pushDeletep(funcrefp), funcrefp);
+                return;
+            }
+            AstFireEvent* const firep
+                = new AstFireEvent{flp, new AstVarRef{flp, eventp, VAccess::WRITE}, false};
+            AstCover* const coverp
+                = new AstCover{flp, new AstPropSpec{flp, nullptr, nullptr, funcrefp}, firep,
+                               VAssertType::CONCURRENT};
+            coverp->isCoverSeq(true);
+            coverp->isSeqEvent(true);
+            m_modp->addStmtsp(coverp);
+            return;
+        }
+        iterateChildren(nodep);
+    }
+    void visit(AstNode* nodep) override { iterateChildren(nodep); }
+
+public:
+    explicit SeqEventLowerVisitor(AstNetlist* nodep) { iterate(nodep); }
+};
+
 }  // namespace
 
 void V3AssertCommon::collectDefaultDisable(AstNetlist* nodep) {
@@ -96,6 +149,11 @@ void V3AssertCommon::collectDefaultDisable(AstNetlist* nodep) {
     { DefaultDisablePropagateVisitor{nodep}; }
 }
 
+void V3AssertCommon::lowerSequenceEvents(AstNetlist* nodep) {
+    { SeqEventLowerVisitor{nodep}; }
+    V3Global::dumpCheckGlobalTree("assertseqevent", 0, dumpTreeEitherLevel() >= 3);
+}
+
 //######################################################################
 // AssertDeFutureVisitor
 // If any AstFuture, then move all non-future varrefs to be one cycle behind,
@@ -228,6 +286,9 @@ class AssertVisitor final : public VNVisitor {
     AstNode* m_failsp = nullptr;  // Current fail statement
     AstNodeCoverOrAssert* m_assertp = nullptr;  // Current assertion
     AstFinal* m_finalp = nullptr;  // Current final block
+    VDouble0 m_statLiftedCaseExprs;  // Count of purified case expressions
+    AstNodeFTask* m_ftaskp = nullptr;  // Current function/task
+    V3UniqueNames m_caseTempNames{"__VCase"};
     // Map from (expression, senTree) to AstAlways that computes delayed values of the expression
     std::unordered_map<VNRef<AstNodeExpr>, std::unordered_map<VNRef<AstSenTree>, AstAlways*>>
         m_modExpr2Sen2DelayedAlwaysp;
@@ -326,8 +387,7 @@ class AssertVisitor final : public VNVisitor {
         }
     }
     AstSampled* newSampledExpr(AstNodeExpr* nodep) {
-        AstSampled* const sampledp = new AstSampled{nodep->fileline(), nodep, nodep->dtypep()};
-        return sampledp;
+        return new AstSampled{nodep->fileline(), nodep, nodep->dtypep(), true};
     }
     AstVarRef* newMonitorNumVarRefp(const AstNode* nodep, VAccess access) {
         if (!m_monitorNumVarp) {
@@ -542,14 +602,19 @@ class AssertVisitor final : public VNVisitor {
 
         bool selfDestruct = false;
         bool passspGated = false;
-        if (const AstCover* const snodep = VN_CAST(nodep, Cover)) {
+        const AstCover* const coverp = VN_CAST(nodep, Cover);
+        // A sequence event control is not an assertion directive; no assertion control
+        const bool seqEvent = coverp && coverp->isSeqEvent();
+        if (coverp) {
             ++m_statCover;
-            if (!v3Global.opt.coverageUser()) {
+            if (seqEvent) {
+                // Keep the event-fire action, with no coverage bucket
+            } else if (!v3Global.opt.coverageUser()) {
                 selfDestruct = true;
             } else {
                 // V3Coverage assigned us a bucket to increment.
-                AstCoverInc* const covincp = VN_AS(snodep->coverincsp(), CoverInc);
-                UASSERT_OBJ(covincp, snodep, "Missing AstCoverInc under assertion");
+                AstCoverInc* const covincp = VN_AS(coverp->coverincsp(), CoverInc);
+                UASSERT_OBJ(covincp, coverp, "Missing AstCoverInc under assertion");
                 covincp->unlinkFrBackWithNext();  // next() might have  AstAssign for trace
                 if (message != "") covincp->declp()->comment(message);
                 if (passsp) {
@@ -593,7 +658,8 @@ class AssertVisitor final : public VNVisitor {
         FileLine* const flp = nodep->fileline();
         bool passspAlreadyGated = false;
         if (passsp && VN_IS(passsp, If)) passspAlreadyGated = VN_AS(passsp, If)->user1();
-        if (passsp && !passspGated && !passspAlreadyGated && !VN_IS(propExprp, PExpr)) {
+        if (passsp && !passspGated && !passspAlreadyGated && !VN_IS(propExprp, PExpr)
+            && !seqEvent) {
             passsp = newIfAssertPassOn(passsp, nodep->directive(), nodep->userType(),
                                        /*vacuous=*/false);
         }
@@ -603,7 +669,7 @@ class AssertVisitor final : public VNVisitor {
         AstNode* bodysp = assertBody(nodep, propExprp, passsp, failsp);
         if (disablep) bodysp = new AstIf{flp, new AstLogNot{flp, disablep}, bodysp};
         // Add assertOn check last, for better combining
-        bodysp = newIfAssertOn(bodysp, nodep->directive(), nodep->userType());
+        if (!seqEvent) bodysp = newIfAssertOn(bodysp, nodep->directive(), nodep->userType());
         if (sentreep) bodysp = new AstAlways{flp, VAlwaysKwd::ALWAYS, sentreep, bodysp};
 
         if (passsp && !passsp->backp()) VL_DO_DANGLING(pushDeletep(passsp), passsp);
@@ -755,6 +821,28 @@ class AssertVisitor final : public VNVisitor {
 
     //========== Case assertions
     void visit(AstCase* nodep) override {
+        // Introduce temporary variable for AstCase if needed - it is done here and not in V3Case
+        // because this phase is before V3Scope and V3Case is not. Doing it before V3Scope ensures
+        // that V3Scope will take care of a scope creation
+        // We also need to do it before V3Begin, co that pragmas like `unique0` also work correctly
+        if (!nodep->exprp()->isPure()) {
+            ++m_statLiftedCaseExprs;
+            FileLine* const fl = nodep->exprp()->fileline();
+            AstVar* const varp = new AstVar{fl, VVarType::BLOCKTEMP, m_caseTempNames.get(nodep),
+                                            nodep->exprp()->dtypep()};
+            AstNodeExpr* const origp = nodep->exprp()->unlinkFrBack();
+            nodep->addHereThisAsNext(
+                new AstAssign{fl, new AstVarRef{fl, varp, VAccess::WRITE}, origp});
+            nodep->exprp(new AstVarRef{fl, varp, VAccess::READ});
+            if (m_ftaskp) {
+                varp->funcLocal(true);
+                varp->lifetime(VLifetime::AUTOMATIC_EXPLICIT);
+                m_ftaskp->stmtsp()->addHereThisAsNext(varp);
+            } else {
+                m_modp->stmtsp()->addHereThisAsNext(varp);
+            }
+            VIsCached::clearCacheTree();
+        }
         iterateChildren(nodep);
         if (!nodep->user1SetOnce()) {
             bool has_default = false;
@@ -983,11 +1071,7 @@ class AssertVisitor final : public VNVisitor {
                         = new AstSenItem{fl, VEdgeType::ET_CHANGED,
                                          // Clone so get VarRef or VarXRef as needed
                                          varrefp->cloneTree(false)};
-                    if (!monSenItemsp) {
-                        monSenItemsp = senItemp;
-                    } else {
-                        monSenItemsp->addNext(senItemp);
-                    }
+                    monSenItemsp = AstNode::addNextNull(monSenItemsp, senItemp);
                 });
             }
 
@@ -1127,12 +1211,11 @@ class AssertVisitor final : public VNVisitor {
         VL_RESTORER(m_modp);
         VL_RESTORER(m_modPastNum);
         VL_RESTORER(m_modStrobeNum);
-        VL_RESTORER(m_modExpr2Sen2DelayedAlwaysp);
         VL_RESTORER(m_finalp);
+        VL_RESTORER_CLEAR(m_modExpr2Sen2DelayedAlwaysp);
         m_modp = nodep;
         m_modPastNum = 0;
         m_modStrobeNum = 0;
-        m_modExpr2Sen2DelayedAlwaysp.clear();
         m_finalp = nullptr;
         iterateChildren(nodep);
     }
@@ -1180,6 +1263,9 @@ public:
         V3Stats::addStat("Assertions, $past variables", m_statPastVars);
         V3Stats::addStat("Assertions, assertOn checks combined", m_statAssertOnCombined);
         V3Stats::addStat("Assertions, assertOn checks hoisted", m_statAssertOnHoisted);
+        V3Stats::addStat("Assertions, lifted impure case expressions", m_statLiftedCaseExprs);
+        // Rewrites can change purity, e.g. by compiling out assertion statements with --no-assert
+        VIsCached::clearCacheTree();
     }
 };
 

src/V3Assert.h

@@ -27,6 +27,7 @@
 class V3AssertCommon final {
 public:
     static void collectDefaultDisable(AstNetlist* nodep) VL_MT_DISABLED;
+    static void lowerSequenceEvents(AstNetlist* nodep) VL_MT_DISABLED;
 };
 
 class V3Assert final {

src/V3AssertPre.cpp

@@ -79,6 +79,14 @@ private:
 
     // METHODS
 
+    static void checkSamplingFuncDType(AstNodeExpr* nodep, const AstNode* exprp) {
+        const AstNodeDType* const dtypep = exprp->dtypep()->skipRefp();
+        if (!dtypep->isIntegralOrPacked()) {
+            nodep->v3error("Expected numeric type, but got a " << dtypep->prettyDTypeNameQ()
+                                                               << " data type");
+        }
+    }
+
     AstSenTree* newSenTree(AstNode* nodep, AstSenTree* useTreep = nullptr,
                            AstNodeCoverOrAssert* cassertp = nullptr) {
         // Create sentree based on clocked or default clock
@@ -372,7 +380,7 @@ private:
                 // #1step means the value that is sampled is always the signal's last value
                 // before the clock edge (IEEE 1800-2023 14.4)
                 AstSampled* const sampledp
-                    = new AstSampled{flp, exprp->cloneTreePure(false), exprp->dtypep()};
+                    = new AstSampled{flp, exprp->cloneTreePure(false), exprp->dtypep(), true};
                 AstAssign* const assignp = new AstAssign{flp, refp, sampledp};
                 m_clockingp->addNextHere(new AstAlways{
                     flp, VAlwaysKwd::ALWAYS,
@@ -683,6 +691,7 @@ private:
     void visit(AstFalling* nodep) override {
         if (nodep->user1SetOnce()) return;
         iterateChildren(nodep);
+        checkSamplingFuncDType(nodep, nodep->exprp());
         FileLine* const fl = nodep->fileline();
         AstNodeExpr* exprp = nodep->exprp()->unlinkFrBack();
         if (exprp->width() > 1) exprp = new AstSel{fl, exprp, 0, 1};
@@ -696,6 +705,7 @@ private:
     void visit(AstFell* nodep) override {
         if (nodep->user1SetOnce()) return;
         iterateChildren(nodep);
+        checkSamplingFuncDType(nodep, nodep->exprp());
         FileLine* const fl = nodep->fileline();
         AstNodeExpr* exprp = nodep->exprp()->unlinkFrBack();
         if (exprp->width() > 1) exprp = new AstSel{fl, exprp, 0, 1};
@@ -712,11 +722,13 @@ private:
     void visit(AstFuture* nodep) override {
         if (nodep->user1SetOnce()) return;
         iterateChildren(nodep);
+        checkSamplingFuncDType(nodep, nodep->exprp());
         AstSenTree* const sentreep = nodep->sentreep();
         if (sentreep) VL_DO_DANGLING(pushDeletep(sentreep->unlinkFrBack()), sentreep);
         nodep->sentreep(newSenTree(nodep));
     }
     void visit(AstPast* nodep) override {
+        checkSamplingFuncDType(nodep, nodep->exprp());
         if (nodep->sentreep()) return;  // Already processed
         iterateChildren(nodep);
         nodep->sentreep(newSenTree(nodep));
@@ -774,6 +786,7 @@ private:
     void visit(AstRising* nodep) override {
         if (nodep->user1SetOnce()) return;
         iterateChildren(nodep);
+        checkSamplingFuncDType(nodep, nodep->exprp());
         FileLine* const fl = nodep->fileline();
         AstNodeExpr* exprp = nodep->exprp()->unlinkFrBack();
         if (exprp->width() > 1) exprp = new AstSel{fl, exprp, 0, 1};
@@ -787,6 +800,7 @@ private:
     void visit(AstRose* nodep) override {
         if (nodep->user1SetOnce()) return;
         iterateChildren(nodep);
+        checkSamplingFuncDType(nodep, nodep->exprp());
         FileLine* const fl = nodep->fileline();
         AstNodeExpr* exprp = nodep->exprp()->unlinkFrBack();
         if (exprp->width() > 1) exprp = new AstSel{fl, exprp, 0, 1};
@@ -849,7 +863,8 @@ private:
 
         // Assertion condition check
         AstLoop* const loopp = new AstLoop{flp};
-        AstNodeExpr* const condp = new AstSampled{flp, nodep->exprp()->unlinkFrBack(), nullptr};
+        AstSampled* const condp
+            = new AstSampled{flp, nodep->exprp()->unlinkFrBack(), nullptr, true};
         loopp->addStmtsp(new AstLoopTest{flp, loopp, new AstLogNot{flp, condp}});
         loopp->addStmtsp(new AstEventControl{flp, sentreep, nullptr});
 
@@ -916,6 +931,7 @@ private:
     void visit(AstStable* nodep) override {
         if (nodep->user1SetOnce()) return;
         iterateChildren(nodep);
+        checkSamplingFuncDType(nodep, nodep->exprp());
         FileLine* const fl = nodep->fileline();
         AstNodeExpr* exprp = nodep->exprp()->unlinkFrBack();
         AstSenTree* sentreep = nodep->sentreep();
@@ -931,6 +947,7 @@ private:
     void visit(AstSteady* nodep) override {
         if (nodep->user1SetOnce()) return;
         iterateChildren(nodep);
+        checkSamplingFuncDType(nodep, nodep->exprp());
         FileLine* const fl = nodep->fileline();
         AstNodeExpr* exprp = nodep->exprp()->unlinkFrBack();
         if (exprp->width() > 1) exprp = new AstSel{fl, exprp, 0, 1};
@@ -941,6 +958,10 @@ private:
         nodep->replaceWith(exprp);
         VL_DO_DANGLING(pushDeletep(nodep), nodep);
     }
+    void visit(AstSampled* nodep) override {
+        iterateChildren(nodep);
+        if (!nodep->internal()) checkSamplingFuncDType(nodep, nodep->exprp());
+    }
 
     // Validate repetition count: must be a non-negative elaboration-time constant.
     // Shared by goto [->N] and nonconsecutive [=N] repetition.
@@ -1203,11 +1224,7 @@ private:
                     AstNode* const nextp = stmtp->nextp();
                     if (AstAssign* const assignp = VN_CAST(stmtp, Assign)) {
                         assignp->unlinkFrBack();
-                        if (!matchAssignsp) {
-                            matchAssignsp = assignp;
-                        } else {
-                            matchAssignsp->addNext(assignp);
-                        }
+                        matchAssignsp = AstNode::addNextNull(matchAssignsp, assignp);
                     }
                     stmtp = nextp;
                 }
@@ -1233,11 +1250,7 @@ private:
                         AstNodeExpr* const assignRhsp = assignp->rhsp()->unlinkFrBack();
                         AstAssignDly* const dlyp = new AstAssignDly{flp, assignLhsp, assignRhsp};
                         VL_DO_DANGLING(pushDeletep(assignp), assignp);
-                        if (!matchAssignsp) {
-                            matchAssignsp = dlyp;
-                        } else {
-                            matchAssignsp->addNext(dlyp);
-                        }
+                        matchAssignsp = AstNode::addNextNull(matchAssignsp, dlyp);
                     }
                     stmtp = nextp;
                 }
@@ -1318,8 +1331,8 @@ private:
             // this tick, p is not required. For s_until_with, p must be true on the q tick too.
             AstNodeExpr* const rawLhsp = nodep->lhsp()->unlinkFrBack();
             AstNodeExpr* const rawRhsp = nodep->rhsp()->unlinkFrBack();
-            AstSampled* const lhsp = new AstSampled{flp, rawLhsp, rawLhsp->dtypep()};
-            AstSampled* const rhsp = new AstSampled{flp, rawRhsp, rawRhsp->dtypep()};
+            AstSampled* const lhsp = new AstSampled{flp, rawLhsp, rawLhsp->dtypep(), true};
+            AstSampled* const rhsp = new AstSampled{flp, rawRhsp, rawRhsp->dtypep(), true};
             AstNodeExpr* finalCondp = rhsp->cloneTreePure(false);
             if (nodep->isOverlapping()) {
                 finalCondp = new AstLogAnd{flp, lhsp->cloneTreePure(false), finalCondp};
@@ -1466,7 +1479,9 @@ private:
         iterateAndNextNull(nodep->sensesp());
         if (m_senip && m_senip != nodep->sensesp())
             nodep->v3warn(E_UNSUPPORTED, "Unsupported: Only one PSL clock allowed per assertion");
-        if (!nodep->disablep() && m_defaultDisablep) {
+        const AstCover* const coverp = VN_CAST(nodep->backp(), Cover);
+        const bool seqEvent = coverp && coverp->isSeqEvent();
+        if (!nodep->disablep() && m_defaultDisablep && !seqEvent) {
             nodep->disablep(m_defaultDisablep->condp()->cloneTreePure(true));
         }
         m_disablep = nodep->disablep();
@@ -1476,7 +1491,7 @@ private:
         if (!VN_AS(nodep->backp(), NodeCoverOrAssert)->immediate()) {
             const AstNodeDType* const propDtp = nodep->propp()->dtypep();
             nodep->propp(new AstSampled{nodep->fileline(), nodep->propp()->unlinkFrBack(),
-                                        propDtp->dtypep()});
+                                        propDtp->dtypep(), true});
         }
         // cover counts non-vacuous matches only (IEEE 1800-2023 16.15.2), so an
         // implication antecedent must hold; assert passes vacuously instead.

src/V3Ast.cpp

@@ -1542,14 +1542,14 @@ string AstNode::instanceStr() const {
     return "";
 }
 void AstNode::v3errorEnd(const std::ostringstream& str) const VL_RELEASE(V3Error::s().m_mutex) {
-    // Don't look for instance name when warning is disabled.
-    // In case of large number of warnings, this can
-    // take significant amount of time
-    const string instanceStrExtra
-        = m_fileline->warnIsOff(V3Error::s().errorCode()) ? "" : instanceStr();
     if (!m_fileline) {
-        V3Error::v3errorEnd(str, instanceStrExtra, nullptr);
+        V3Error::v3errorEnd(str, "", nullptr);
     } else {
+        // Don't look for instance name when warning is disabled.
+        // In case of large number of warnings, this can
+        // take significant amount of time
+        const string instanceStrExtra
+            = m_fileline->warnIsOff(V3Error::s().errorCode()) ? "" : instanceStr();
         std::ostringstream nsstr;
         nsstr << str.str();
         if (debug()) {
@@ -1735,12 +1735,15 @@ AstNodeDType* AstNode::getCommonClassTypep(AstNode* node1p, AstNode* node2p) {
         if (castable == VCastable::DYNAMIC_CLASS) return node2p->dtypep();
     }
 
-    AstClassRefDType* classDtypep1 = VN_CAST(node1p->dtypep(), ClassRefDType);
+    AstClassRefDType* classDtypep1 = VN_CAST(node1p->dtypep()->skipRefp(), ClassRefDType);
     while (classDtypep1) {
         const VCastable castable = computeCastable(classDtypep1, node2p->dtypep(), node2p);
         if (castable == VCastable::COMPATIBLE) return classDtypep1;
-        const AstClassExtends* const extendsp = classDtypep1->classp()->extendsp();
-        classDtypep1 = extendsp ? VN_AS(extendsp->dtypep(), ClassRefDType) : nullptr;
+        AstClassExtends* const extendsp = classDtypep1->classp()->extendsp();
+        if (!extendsp) break;
+        AstNodeDType* const edtp
+            = extendsp->dtypep() ? extendsp->dtypep() : extendsp->childDTypep();
+        classDtypep1 = VN_AS(edtp->skipRefp(), ClassRefDType);
     }
     return nullptr;
 }

src/V3Ast.h

@@ -730,6 +730,7 @@ public:
 
     // ACCESSORS for specific types
     // Alas these can't be virtual or they break when passed a nullptr
+    bool isDisableQueuePushSelfStmt();
     inline bool isClassHandleValue() const;
     inline bool isNull() const;
     inline bool isZero() const;

src/V3AstAttr.h

@@ -299,6 +299,34 @@ constexpr VAssertType::en operator|(VAssertType::en lhs, VAssertType::en rhs) {
 
 // ######################################################################
 
+class VPropStrength final {
+public:
+    enum en : uint8_t {
+        DEFAULT = 0,  // Resolve from assertion/coverage context
+        WEAK,
+        STRONG,
+    };
+    enum en m_e;
+    // cppcheck-suppress noExplicitConstructor
+    constexpr VPropStrength(en _e)
+        : m_e{_e} {}
+    const char* ascii() const {
+        static const char* const names[] = {"default", "weak", "strong"};
+        return names[m_e];
+    }
+};
+constexpr bool operator==(const VPropStrength& lhs, const VPropStrength& rhs) {
+    return lhs.m_e == rhs.m_e;
+}
+constexpr bool operator==(const VPropStrength& lhs, VPropStrength::en rhs) {
+    return lhs.m_e == rhs;
+}
+constexpr bool operator!=(const VPropStrength& lhs, VPropStrength::en rhs) {
+    return lhs.m_e != rhs;
+}
+
+// ######################################################################
+
 class VAttrType final {
 public:
     // clang-format off

src/V3AstNodeDType.h

@@ -584,6 +584,7 @@ class AstClassRefDType final : public AstNodeDType {
     //
     // @astgen ptr := m_classp : Optional[AstClass]  // data type pointed to, BELOW the AstTypedef
     // @astgen ptr := m_classOrPackagep : Optional[AstNodeModule]  // Package hierarchy
+    bool m_rawPointer = false;  // Emit as a non-owning C++ pointer rather than VlClassRef
 public:
     AstClassRefDType(FileLine* fl, AstClass* classp, AstPin* paramsp)
         : ASTGEN_SUPER_ClassRefDType(fl)
@@ -595,7 +596,8 @@ public:
     // METHODS
     bool sameNode(const AstNode* samep) const override {
         const AstClassRefDType* const asamep = VN_DBG_AS(samep, ClassRefDType);
-        return (m_classp == asamep->m_classp && m_classOrPackagep == asamep->m_classOrPackagep);
+        return (m_classp == asamep->m_classp && m_classOrPackagep == asamep->m_classOrPackagep
+                && m_rawPointer == asamep->m_rawPointer);
     }
     bool similarDTypeNode(const AstNodeDType* samep) const override;
     void dump(std::ostream& str = std::cout) const override;
@@ -613,6 +615,9 @@ public:
     void classOrPackagep(AstNodeModule* nodep) { m_classOrPackagep = nodep; }
     AstClass* classp() const VL_MT_STABLE { return m_classp; }
     void classp(AstClass* nodep) { m_classp = nodep; }
+    bool rawPointer() const { return m_rawPointer; }
+    void rawPointer(bool flag) { m_rawPointer = flag; }
+    static void selfTest();
     bool isCompound() const override { return true; }
 };
 class AstConstDType final : public AstNodeDType {
@@ -968,7 +973,7 @@ class AstMemberDType final : public AstNodeDType {
     string m_tag;  // Holds the string of the verilator tag -- used in JSON output.
     int m_lsb = -1;  // Within this level's packed struct, the LSB of the first bit of the member
     bool m_constrainedRand = false;
-    // UNSUP: int m_randType;    // Randomization type (IEEE)
+    VRandAttr m_rand;  // Randomizability of this member (rand, randc, etc)
 public:
     AstMemberDType(FileLine* fl, const string& name, VFlagChildDType, AstNodeDType* dtp,
                    AstNode* valuep)
@@ -1025,6 +1030,8 @@ public:
     }
     bool isConstrainedRand() const { return m_constrainedRand; }
     void markConstrainedRand(bool flag) { m_constrainedRand = flag; }
+    VRandAttr rand() const { return m_rand; }
+    void rand(const VRandAttr flag) { m_rand = flag; }
 };
 class AstNBACommitQueueDType final : public AstNodeDType {
     // @astgen ptr := m_subDTypep : AstNodeDType  // Type of the corresponding variable

src/V3AstNodeExpr.h

@@ -905,7 +905,7 @@ public:
     string name() const override VL_MT_STABLE { return m_name; }  // * = Var name
     // There's no classOrPackagep(); use classOrPackageNodep() to get Node,
     // or iterating to package with classOrPackageSkipp()
-    AstNodeModule* classOrPackageSkipp() const;
+    AstNodeModule* classOrPackageSkipp(const bool doRefs = true) const;
     AstNode* classOrPackageNodep() const { return m_classOrPackageNodep; }
     void classOrPackageNodep(AstNode* nodep) { m_classOrPackageNodep = nodep; }
     void classOrPackagep(AstNodeModule* nodep) {
@@ -2262,24 +2262,25 @@ public:
     bool cleanOut() const override { V3ERROR_NA_RETURN(false); }
 };
 class AstSConsRep final : public AstNodeExpr {
-    // Consecutive repetition [*N], [*N:M], [+], [*] (IEEE 1800-2023 16.9.2)
+    // Consecutive repetition [*N], [*N:M], [*N:$], [+], [*] (IEEE 1800-2023 16.9.2)
     // op1 := exprp -- the repeated expression
-    // op2 := countp -- min repetition count (N); always a positive constant after V3Width
+    // op2 := countp -- min repetition count (N); always a non-negative constant after V3Width
     // op3 := maxCountp -- max repetition count (M); nullptr when exact or unbounded
     //
     // Encoding:
     //   [*N]:   countp=N, maxCountp=nullptr, unbounded=false
     //   [*N:M]: countp=N, maxCountp=M,       unbounded=false
+    //   [*N:$]: countp=N, maxCountp=nullptr,  unbounded=true
     //   [+]:    countp=1, maxCountp=nullptr,  unbounded=true  (= [*1:$])
     //   [*]:    countp=0, maxCountp=nullptr,  unbounded=true  (= [*0:$])
     //
     // Lowering:
     //   Exact [*N] standalone: V3AssertPre saturating counter
-    //   All other forms and all SExpr-contained forms: V3AssertProp PExpr loop
+    //   All other forms and all SExpr-contained forms: V3AssertNfa
     // @astgen op1 := exprp : AstNodeExpr
     // @astgen op2 := countp : AstNodeExpr
     // @astgen op3 := maxCountp : Optional[AstNodeExpr]
-    const bool m_unbounded = false;  // True for [+] and [*] (upper bound is $)
+    const bool m_unbounded = false;  // True when the upper bound is $
 public:
     // Exact [*N]
     AstSConsRep(FileLine* fl, AstNodeExpr* exprp, AstNodeExpr* countp)
@@ -2287,7 +2288,7 @@ public:
         this->exprp(exprp);
         this->countp(countp);
     }
-    // Range [*N:M] or unbounded [+]/[*]
+    // Range [*N:M] or unbounded [*N:$]/[+]/[*]
     AstSConsRep(FileLine* fl, AstNodeExpr* exprp, AstNodeExpr* countp, AstNodeExpr* maxCountp,
                 bool unbounded)
         : ASTGEN_SUPER_SConsRep(fl)
@@ -2554,19 +2555,26 @@ public:
 class AstSampled final : public AstNodeExpr {
     // Verilog $sampled
     // @astgen op1 := exprp : AstNode<AstNodeExpr|AstPropSpec>
+    bool m_internal : 1;  // Internally created, not from a source $sampled
 public:
-    AstSampled(FileLine* fl, AstNode* exprp, AstNodeDType* dtypep)
-        : ASTGEN_SUPER_Sampled(fl) {
+    AstSampled(FileLine* fl, AstNode* exprp, AstNodeDType* dtypep, bool internal = false)
+        : ASTGEN_SUPER_Sampled(fl)
+        , m_internal{internal} {
         this->exprp(exprp);
         this->dtypep(dtypep);
     }
     ASTGEN_MEMBERS_AstSampled;
+    void dump(std::ostream& str) const override;
+    void dumpJson(std::ostream& str) const override;
     string emitVerilog() override { return "$sampled(%l)"; }
     string emitC() override { V3ERROR_NA_RETURN(""); }
     string emitSimpleOperator() override { V3ERROR_NA_RETURN(""); }
     bool cleanOut() const override { V3ERROR_NA_RETURN(""); }
     int instrCount() const override { return 0; }
-    bool sameNode(const AstNode* /*samep*/) const override { return true; }
+    bool sameNode(const AstNode* samep) const override {
+        return m_internal == VN_DBG_AS(samep, Sampled)->m_internal;
+    }
+    bool internal() const { return m_internal; }
     bool isSystemFunc() const override { return true; }
 };
 class AstScopeName final : public AstNodeExpr {
@@ -3258,6 +3266,7 @@ public:
     bool sizeMattersRhs() const override { return false; }
     bool isSystemFunc() const override { return true; }
     int instrCount() const override { return widthInstrs() * 64; }
+    bool isPure() override { return false; }  // SPECIAL: $display has 'visual' ordering
 };
 class AstFUngetC final : public AstNodeBiop {
 public:
@@ -3978,12 +3987,16 @@ public:
 class AstSAnd final : public AstNodeBiop {
     // Sequence 'and' (IEEE 1800-2023 16.9.5): both operand sequences must match.
     // Operates on match sets, not values. For boolean operands, lowered to AstLogAnd.
+    const bool m_propertyControl;  // Parser-generated property if/case branch conjunction
 public:
-    AstSAnd(FileLine* fl, AstNodeExpr* lhsp, AstNodeExpr* rhsp)
-        : ASTGEN_SUPER_SAnd(fl, lhsp, rhsp) {
+    AstSAnd(FileLine* fl, AstNodeExpr* lhsp, AstNodeExpr* rhsp, bool propertyControl = false)
+        : ASTGEN_SUPER_SAnd(fl, lhsp, rhsp)
+        , m_propertyControl{propertyControl} {
         dtypeSetBit();
     }
     ASTGEN_MEMBERS_AstSAnd;
+    void dump(std::ostream& str) const override;
+    void dumpJson(std::ostream& str) const override;
     void numberOperate(V3Number& out, const V3Number& lhs, const V3Number& rhs) override {
         out.opLogAnd(lhs, rhs);
     }
@@ -3997,6 +4010,10 @@ public:
     bool sizeMattersRhs() const override { return false; }
     int instrCount() const override { return widthInstrs() + INSTR_COUNT_BRANCH; }
     bool isMultiCycleSva() const override { return true; }
+    bool sameNode(const AstNode* samep) const override {  // LCOV_EXCL_LINE
+        return m_propertyControl == VN_DBG_AS(samep, SAnd)->m_propertyControl;  // LCOV_EXCL_LINE
+    }
+    bool propertyControl() const { return m_propertyControl; }
 };
 class AstSIntersect final : public AstNodeBiop {
     // Sequence 'intersect' (IEEE 1800-2023 16.9.6): both operands match with equal length.
@@ -4886,9 +4903,11 @@ public:
     bool cleanRhs() const override { return true; }
     bool sizeMattersLhs() const override { return false; }
     bool sizeMattersRhs() const override { return false; }
-    bool isGateOptimizable() const override { return false; }  // AssocSel creates on miss
+    bool isGateOptimizable() const override {
+        return !isLValue();  // AssocSel creates on miss
+    }
     bool isPredictOptimizable() const override { return false; }
-    bool isPure() override { return false; }  // AssocSel creates on miss
+    bool isPure() override { return !isLValue(); }  // AssocSel creates on miss
     bool sameNode(const AstNode* /*samep*/) const override { return true; }
     int instrCount() const override { return widthInstrs(); }
 };

src/V3AstNodeOther.h

@@ -94,6 +94,7 @@ class AstNodeFTask VL_NOT_FINAL : public AstNode {
     // @astgen op4 := scopeNamep : Optional[AstScopeName]
     string m_name;  // Name of task
     string m_cname;  // Name of task if DPI import
+    string m_dpiCDecl;  // Custom DPI-C function declaration
     string m_ifacePortName;  // Interface port name for out-of-block definition (IEEE 25.8)
     uint64_t m_dpiOpenParent = 0;  // DPI import open array, if !=0, how many callees
     bool m_taskPublic : 1;  // Public task
@@ -199,6 +200,9 @@ public:
     void dpiOpenChild(bool flag) { m_dpiOpenChild = flag; }
     bool dpiTask() const { return m_dpiTask; }
     void dpiTask(bool flag) { m_dpiTask = flag; }
+    bool dpiCDeclOverride() const { return !m_dpiCDecl.empty(); }
+    const string& dpiCDecl() const { return m_dpiCDecl; }
+    void dpiCDecl(const string& cDecl) { m_dpiCDecl = cDecl; }
     bool isConstructor() const { return m_isConstructor; }
     void isConstructor(bool flag) { m_isConstructor = flag; }
     bool isHideLocal() const { return m_isHideLocal; }
@@ -504,6 +508,7 @@ class AstCFunc final : public AstNode {
     // @astgen op1 := argsp : List[AstVar]  // Argument (and return value) variables
     // @astgen op2 := varsp : List[AstVar]  // Local variables
     // @astgen op3 := stmtsp : List[AstNode]
+    // @astgen op4 := scopeNamep : Optional[AstScopeName]  // Scoping context for DPI export
     //
     // @astgen ptr := m_scopep : Optional[AstScope]  // Scope that function is under
     string m_name;
@@ -511,6 +516,7 @@ class AstCFunc final : public AstNode {
     string m_rtnType;  // void, bool, or other return type
     string m_argTypes;  // Argument types
     string m_ifdef;  // #ifdef symbol around this function
+    string m_cDecl;  // Custom DPI-C function declaration
     VBoolOrUnknown m_isConst;  // Function is declared const (*this not changed)
     bool m_isStatic : 1;  // Function is static (no need for a 'this' pointer)
     bool m_isTrace : 1;  // Function is related to tracing
@@ -640,6 +646,9 @@ public:
     void dpiImportPrototype(bool flag) { m_dpiImportPrototype = flag; }
     bool dpiImportWrapper() const { return m_dpiImportWrapper; }
     void dpiImportWrapper(bool flag) { m_dpiImportWrapper = flag; }
+    bool dpiCDeclOverride() const { return !m_cDecl.empty(); }
+    const string& dpiCDecl() const { return m_cDecl; }
+    void dpiCDecl(const string& cDecl) { m_cDecl = cDecl; }
     bool isCoroutine() const { return m_rtnType == "VlCoroutine"; }
     void recursive(bool flag) { m_recursive = flag; }
     bool recursive() const { return m_recursive; }
@@ -650,20 +659,10 @@ public:
     void cost(int cost) { m_cost = cost; }
     // Special methods
     bool emptyBody() const {
-        return !keepIfEmpty() && !argsp() && !varsp() && !stmtsp() && !isVirtual()
+        return !keepIfEmpty() && !argsp() && !varsp() && !stmtsp() && !scopeNamep() && !isVirtual()
                && !dpiImportPrototype();
     }
 };
-class AstCLocalScope final : public AstNode {
-    // Pack statements into an unnamed scope when generating C++
-    // @astgen op1 := stmtsp : List[AstNode]
-public:
-    AstCLocalScope(FileLine* fl, AstNode* stmtsp)
-        : ASTGEN_SUPER_CLocalScope(fl) {
-        addStmtsp(stmtsp);
-    }
-    ASTGEN_MEMBERS_AstCLocalScope;
-};
 class AstCUse final : public AstNode {
     // C++ use of a class or #include; indicates need of forward declaration
     // Parents:  NODEMODULE
@@ -844,7 +843,7 @@ class AstClocking final : public AstNode {
     // @astgen op2 := itemsp : List[AstNode]
     // @astgen op3 := eventp : Optional[AstVar]
     std::string m_name;  // Clocking block name
-    const bool m_isDefault;  // True if default clocking
+    bool m_isDefault;  // True if default clocking
     const bool m_isGlobal;  // True if global clocking
 
 public:
@@ -865,6 +864,7 @@ public:
     bool isDefault() const { return m_isDefault; }
     bool isGlobal() const { return m_isGlobal; }
     AstVar* ensureEventp(bool childDType = false);
+    void makeDefault() { m_isDefault = true; }
 };
 class AstClockingItem final : public AstNode {
     // Parents:  CLOCKING
@@ -1042,22 +1042,6 @@ public:
     void isStatic(bool flag) { m_isStatic = flag; }
     bool isStatic() const { return m_isStatic; }
 };
-class AstConstraintBefore final : public AstNode {
-    // Constraint solve before item
-    // @astgen op1 := lhssp : List[AstNodeExpr]
-    // @astgen op2 := rhssp : List[AstNodeExpr]
-public:
-    AstConstraintBefore(FileLine* fl, AstNodeExpr* lhssp, AstNodeExpr* rhssp)
-        : ASTGEN_SUPER_ConstraintBefore(fl) {
-        addLhssp(lhssp);
-        addRhssp(rhssp);
-    }
-    ASTGEN_MEMBERS_AstConstraintBefore;
-    bool isGateOptimizable() const override { return false; }
-    bool isPredictOptimizable() const override { return false; }
-    bool sameNode(const AstNode* /*samep*/) const override { return true; }
-};
-
 class AstCoverBin final : public AstNode {
     // Captures data for a coverpoint 'bins' declaration
     // @astgen op1 := rangesp : List[AstNode]
@@ -1222,6 +1206,16 @@ public:
     ASTGEN_MEMBERS_AstDefParam;
     bool sameNode(const AstNode*) const override { return true; }
 };
+class AstDefaultClocking final : public AstNode {
+    std::string m_name;  // Clocking block name
+
+public:
+    AstDefaultClocking(FileLine* fl, const std::string& name)
+        : ASTGEN_SUPER_DefaultClocking(fl)
+        , m_name{name} {}
+    ASTGEN_MEMBERS_AstDefaultClocking;
+    std::string name() const override VL_MT_STABLE { return m_name; }
+};
 class AstDefaultDisable final : public AstNode {
     // @astgen op1 := condp : AstNodeExpr
 
@@ -1679,17 +1673,24 @@ class AstPropSpec final : public AstNode {
     // @astgen op1 := sensesp : Optional[AstSenItem]
     // @astgen op2 := disablep : Optional[AstNodeExpr]
     // @astgen op3 := propp : AstNode
+    VPropStrength m_propStrength = VPropStrength::DEFAULT;
+
 public:
-    AstPropSpec(FileLine* fl, AstSenItem* sensesp, AstNodeExpr* disablep, AstNode* propp)
-        : ASTGEN_SUPER_PropSpec(fl) {
+    AstPropSpec(FileLine* fl, AstSenItem* sensesp, AstNodeExpr* disablep, AstNode* propp,
+                VPropStrength propStrength = VPropStrength::DEFAULT)
+        : ASTGEN_SUPER_PropSpec(fl)
+        , m_propStrength{propStrength} {
         this->sensesp(sensesp);
         this->disablep(disablep);
         this->propp(propp);
     }
     ASTGEN_MEMBERS_AstPropSpec;
+    void dump(std::ostream& str) const override;
+    void dumpJson(std::ostream& str) const override;
     bool hasDType() const override VL_MT_SAFE {
         return true;
     }  // Used under Cover, which expects a bool child
+    VPropStrength propStrength() const { return m_propStrength; }
 };
 class AstPull final : public AstNode {
     // @astgen op1 := lhsp : AstNodeExpr
@@ -2784,11 +2785,14 @@ class AstCoverCross final : public AstNodeFuncCovItem {
     // @astgen op2 := optionsp : List[AstCoverOption]     // post-LinkParse only
     // @astgen op3 := rawBodyp : List[AstNode]  // Parse: raw cross_body items;
     //                                          // post-LinkParse: empty
+    // @astgen op4 := iffp     : Optional[AstNodeExpr]  // Conditional sampling guard
 public:
-    AstCoverCross(FileLine* fl, const string& name, AstCoverpointRef* itemsp)
+    AstCoverCross(FileLine* fl, const string& name, AstCoverpointRef* itemsp,
+                  AstNodeExpr* iffp = nullptr)
         : ASTGEN_SUPER_CoverCross(fl, name) {
         UASSERT(itemsp, "AstCoverCross requires at least one coverpoint reference");
         addItemsp(itemsp);
+        this->iffp(iffp);
     }
     ASTGEN_MEMBERS_AstCoverCross;
     void dump(std::ostream& str) const override;
@@ -2889,6 +2893,7 @@ class AstClass final : public AstNodeModule {
     // @astgen op4 := extendsp : List[AstClassExtends]
     // MEMBERS
     // @astgen ptr := m_classOrPackagep : Optional[AstClassPackage]  // Package to be emitted with
+    // @astgen ptr := m_covergroupEnclosingClassp : Optional[AstClass]  // Lexical enclosing class
     uint32_t m_declTokenNum;  // Declaration token number
     VBaseOverride m_baseOverride;  // BaseOverride (inital/final/extends)
     bool m_covergroup = false;  // Is covergroup (TODO perhaps make a new Ast node type for CG?)
@@ -2913,6 +2918,10 @@ public:
     bool timescaleMatters() const override { return false; }
     AstClassPackage* classOrPackagep() const VL_MT_STABLE { return m_classOrPackagep; }
     void classOrPackagep(AstClassPackage* classpackagep) { m_classOrPackagep = classpackagep; }
+    AstClass* covergroupEnclosingClassp() const VL_MT_STABLE {
+        return m_covergroupEnclosingClassp;
+    }
+    void covergroupEnclosingClassp(AstClass* classp) { m_covergroupEnclosingClassp = classp; }
     AstNode* membersp() const VL_MT_STABLE { return stmtsp(); }
     void addMembersp(AstNode* nodep) { addStmtsp(nodep); }
     bool isCovergroup() const { return m_covergroup; }

src/V3AstNodeStmt.h

@@ -297,6 +297,16 @@ public:
     AstSenTree* sentreep() const { return m_sentreep; }
     void clearSentreep() { m_sentreep = nullptr; }
 };
+class AstCLocalScope final : public AstNodeStmt {
+    // Pack statements into an unnamed scope when generating C++
+    // @astgen op1 := stmtsp : List[AstNode]
+public:
+    AstCLocalScope(FileLine* fl, AstNode* stmtsp)
+        : ASTGEN_SUPER_CLocalScope(fl) {
+        addStmtsp(stmtsp);
+    }
+    ASTGEN_MEMBERS_AstCLocalScope;
+};
 class AstCReturn final : public AstNodeStmt {
     // C++ return from a function
     // @astgen op1 := lhsp : AstNodeExpr
@@ -451,6 +461,21 @@ public:
     bool sameNode(const AstNode* samep) const override { return true; }  // Ignore name in comments
     virtual bool showAt() const { return m_showAt; }
 };
+class AstConstraintBefore final : public AstNodeStmt {
+    // Constraint solve before item
+    // @astgen op1 := lhssp : List[AstNodeExpr]
+    // @astgen op2 := rhssp : List[AstNodeExpr]
+public:
+    AstConstraintBefore(FileLine* fl, AstNodeExpr* lhssp, AstNodeExpr* rhssp)
+        : ASTGEN_SUPER_ConstraintBefore(fl) {
+        addLhssp(lhssp);
+        addRhssp(rhssp);
+    }
+    ASTGEN_MEMBERS_AstConstraintBefore;
+    bool isGateOptimizable() const override { return false; }
+    bool isPredictOptimizable() const override { return false; }
+    bool sameNode(const AstNode* /*samep*/) const override { return true; }
+};
 class AstConstraintExpr final : public AstNodeStmt {
     // Constraint expression
     // @astgen op1 := exprp : AstNodeExpr
@@ -1568,15 +1593,23 @@ class AstFork final : public AstNodeBlock {
     //
     // @astgen op3 := forksp : List[AstBegin]
     const VJoinType m_joinType;  // Join keyword type
+    bool m_immediateStart = false;  // Fork starts before its parent blocks or exits
+
 public:
     AstFork(FileLine* fl, VJoinType joinType, const string& name = "")
         : ASTGEN_SUPER_Fork(fl, name)
         , m_joinType{joinType} {}
     ASTGEN_MEMBERS_AstFork;
+    bool sameNode(const AstNode* samep) const override {
+        const AstFork* const asamep = VN_DBG_AS(samep, Fork);
+        return joinType() == asamep->joinType() && immediateStart() == asamep->immediateStart();
+    }
     bool isTimingControl() const override { return !joinType().joinNone(); }
     void dump(std::ostream& str) const override;
     void dumpJson(std::ostream& str) const override;
     VJoinType joinType() const { return m_joinType; }
+    bool immediateStart() const { return m_immediateStart; }
+    void immediateStart(bool flag) { m_immediateStart = flag; }
 };
 
 // === AstNodeCoverOrAssert ===
@@ -1612,6 +1645,8 @@ class AstCover final : public AstNodeCoverOrAssert {
     // @astgen op3 := coverincsp: List[AstNode] // Coverage node
     bool m_isCoverSeq = false;  // 'cover sequence' (IEEE 1800-2023 16.14.3): fires per
                                 // end-of-match, not per property success
+    bool m_isSeqEvent = false;  // Synthesized for a sequence used as an event control
+                                // (IEEE 1800-2023 9.4.2.4)
 public:
     ASTGEN_MEMBERS_AstCover;
     AstCover(FileLine* fl, AstNode* propp, AstNode* stmtsp, VAssertType type,
@@ -1622,6 +1657,8 @@ public:
     void dumpJson(std::ostream& str) const override;
     bool isCoverSeq() const { return m_isCoverSeq; }
     void isCoverSeq(bool flag) { m_isCoverSeq = flag; }
+    bool isSeqEvent() const { return m_isSeqEvent; }
+    void isSeqEvent(bool flag) { m_isSeqEvent = flag; }
 };
 class AstRestrict final : public AstNodeCoverOrAssert {
 public:

src/V3AstNodes.cpp

@@ -108,6 +108,21 @@ int AstNodeSel::bitConst() const {
     return (constp ? constp->toSInt() : 0);
 }
 
+bool AstNode::isDisableQueuePushSelfStmt() {
+    // Detect LinkJump-generated registration:
+    // __VprocessQueue_*.push_back(std::process::self())
+    AstStmtExpr* const stmtExprp = VN_CAST(this, StmtExpr);
+    if (!stmtExprp) return false;
+    AstCMethodHard* const methodp = VN_CAST(stmtExprp->exprp(), CMethodHard);
+    if (!methodp || methodp->name() != "push_back") return false;
+    AstNode* const basep = AstArraySel::baseFromp(methodp->fromp(), false);
+    if (AstVarRef* const refp = VN_CAST(basep, VarRef)) return refp->varp()->processQueue();
+    if (AstMemberSel* const selp = VN_CAST(basep, MemberSel)) {
+        return selp->varp() && selp->varp()->processQueue();
+    }
+    return false;
+}
+
 void AstNodeStmt::dump(std::ostream& str) const { this->AstNode::dump(str); }
 void AstNodeStmt::dumpJson(std::ostream& str) const { dumpJsonGen(str); }
 
@@ -468,6 +483,14 @@ void AstSConsRep::dumpJson(std::ostream& str) const {
     dumpJsonBoolFuncIf(str, unbounded);
     dumpJsonGen(str);
 }  // LCOV_EXCL_STOP
+void AstSAnd::dump(std::ostream& str) const {
+    this->AstNodeExpr::dump(str);
+    if (propertyControl()) str << " [PROPERTY_CONTROL]";
+}
+void AstSAnd::dumpJson(std::ostream& str) const {
+    dumpJsonBoolFuncIf(str, propertyControl);
+    dumpJsonGen(str);
+}
 void AstPropAlways::dump(std::ostream& str) const {
     this->AstNodeExpr::dump(str);
     if (isStrong()) str << " [strong]";
@@ -1179,7 +1202,8 @@ AstNodeDType::CTypeRecursed AstNodeDType::cTypeRecurse(bool compound, bool packe
         info.m_type = "VlSampleQueue<" + sub.m_type + ">";
     } else if (const auto* const adtypep = VN_CAST(dtypep, ClassRefDType)) {
         UASSERT_OBJ(!packed, this, "Unsupported type for packed struct or union");
-        info.m_type = "VlClassRef<" + EmitCUtil::prefixNameProtect(adtypep) + ">";
+        const string className = EmitCUtil::prefixNameProtect(adtypep);
+        info.m_type = adtypep->rawPointer() ? className + "*" : "VlClassRef<" + className + ">";
     } else if (const auto* const adtypep = VN_CAST(dtypep, IfaceRefDType)) {
         UASSERT_OBJ(!packed, this, "Unsupported type for packed struct or union");
         info.m_type = EmitCUtil::prefixNameProtect(adtypep->ifaceViaCellp()) + "*";
@@ -1401,6 +1425,9 @@ AstNode* AstArraySel::baseFromp(AstNode* nodep, bool overMembers) {
         } else if (VN_IS(nodep, WildcardSel)) {
             nodep = VN_AS(nodep, WildcardSel)->fromp();
             continue;
+        } else if (VN_IS(nodep, CMethodHard)) {
+            nodep = VN_AS(nodep, CMethodHard)->fromp();
+            continue;
         } else if (overMembers && VN_IS(nodep, MemberSel)) {
             nodep = VN_AS(nodep, MemberSel)->fromp();
             continue;
@@ -1977,6 +2004,18 @@ string AstBasicDType::prettyDTypeName(bool) const {
 void AstNodeExpr::dump(std::ostream& str) const { this->AstNode::dump(str); }
 void AstNodeExpr::dumpJson(std::ostream& str) const { dumpJsonGen(str); }
 
+void AstPropSpec::dump(std::ostream& str) const {
+    this->AstNode::dump(str);
+    if (propStrength() != VPropStrength::DEFAULT) {
+        str << " [" << VString::upcase(propStrength().ascii()) << "]";
+    }
+}
+void AstPropSpec::dumpJson(std::ostream& str) const {
+    if (propStrength() != VPropStrength::DEFAULT)
+        dumpJsonStr(str, "strength", propStrength().ascii());
+    dumpJsonGen(str);
+}
+
 AstConst::~AstConst() {
     // Only rare constants carry originating parameter-name metadata. For all other AstConst nodes,
     // the V3Number bit keeps this destructor from touching AstNetlist's side table. When the bit
@@ -2022,6 +2061,8 @@ bool AstNodeExpr::isLValue() const {
         return varrefp->access().isWriteOrRW();
     } else if (const AstMemberSel* const memberselp = VN_CAST(this, MemberSel)) {
         return memberselp->access().isWriteOrRW();
+    } else if (const AstStructSel* const structselp = VN_CAST(this, StructSel)) {
+        return structselp->fromp()->isLValue();
     } else if (const AstSel* const selp = VN_CAST(this, Sel)) {
         return selp->fromp()->isLValue();
     } else if (const AstNodeSel* const nodeSelp = VN_CAST(this, NodeSel)) {
@@ -2181,8 +2222,22 @@ void AstClassRefDType::dump(std::ostream& str) const {
     } else {
         str << " -> UNLINKED";
     }
+    if (rawPointer()) str << " [RAWPTR]";
+}
+void AstClassRefDType::dumpJson(std::ostream& str) const {
+    dumpJsonBoolFuncIf(str, rawPointer);
+    dumpJsonGen(str);
+}
+void AstClassRefDType::selfTest() {
+    FileLine* const fl = new FileLine{FileLine::commandLineFilename()};
+    AstClassRefDType* const owningp = new AstClassRefDType{fl, nullptr, nullptr};
+    AstClassRefDType* const rawp = new AstClassRefDType{fl, nullptr, nullptr};
+    rawp->rawPointer(true);
+    UASSERT_OBJ(!owningp->sameNode(rawp) && !rawp->sameNode(owningp) && rawp->sameNode(rawp), rawp,
+                "Raw class pointer must have distinct type identity");
+    VL_DO_DANGLING(owningp->deleteTree(), owningp);
+    VL_DO_DANGLING(rawp->deleteTree(), rawp);
 }
-void AstClassRefDType::dumpJson(std::ostream& str) const { dumpJsonGen(str); }
 void AstClassRefDType::dumpSmall(std::ostream& str) const {
     this->AstNodeDType::dumpSmall(str);
     str << "class:" << name();
@@ -2241,9 +2296,11 @@ void AstNodeCoverOrAssert::dumpJson(std::ostream& str) const {
 void AstCover::dump(std::ostream& str) const {
     this->AstNodeCoverOrAssert::dump(str);
     if (isCoverSeq()) str << " [COVERSEQ]";
+    if (isSeqEvent()) str << " [SEQEVENT]";
 }
 void AstCover::dumpJson(std::ostream& str) const {
     dumpJsonBoolFuncIf(str, isCoverSeq);
+    dumpJsonBoolFuncIf(str, isSeqEvent);
     this->AstNodeCoverOrAssert::dumpJson(str);
 }
 void AstClocking::dump(std::ostream& str) const {
@@ -2486,12 +2543,14 @@ const char* AstLoopTest::broken() const {
 void AstMemberDType::dump(std::ostream& str) const {
     this->AstNodeDType::dump(str);
     if (isConstrainedRand()) str << " [CONSTRAINEDRAND]";
+    if (rand().isRandomizable()) str << " [" << rand() << "]";
     if (name() != "") str << " name=" << name();
     if (tag() != "") str << " tag=" << tag();
 }
 
 void AstMemberDType::dumpJson(std::ostream& str) const {
     dumpJsonBoolFuncIf(str, isConstrainedRand);
+    if (rand().isRandomizable()) dumpJsonStr(str, "rand", rand().ascii());
     dumpJsonStrFunc(str, name);
     dumpJsonStrFunc(str, tag);
     dumpJsonGen(str);
@@ -3032,6 +3091,14 @@ void AstSFormatF::dumpJson(std::ostream& str) const {
     dumpJsonBoolFuncIf(str, exprFormat);
     dumpJsonBoolFuncIf(str, optionalFormat);
 }
+void AstSampled::dump(std::ostream& str) const {
+    this->AstNodeExpr::dump(str);
+    if (internal()) str << " [INTERNAL]";
+}
+void AstSampled::dumpJson(std::ostream& str) const {
+    dumpJsonBoolFuncIf(str, internal);
+    dumpJsonGen(str);
+}
 void AstSel::dump(std::ostream& str) const {
     this->AstNodeBiop::dump(str);
     str << " widthConst=" << this->widthConst();
@@ -3401,7 +3468,7 @@ void AstClassOrPackageRef::dump(std::ostream& str) const {
     }
 }
 void AstClassOrPackageRef::dumpJson(std::ostream& str) const { dumpJsonGen(str); }
-AstNodeModule* AstClassOrPackageRef::classOrPackageSkipp() const {
+AstNodeModule* AstClassOrPackageRef::classOrPackageSkipp(const bool doRefs) const {
     AstNode* foundp = m_classOrPackageNodep;
     AstNode* lastp = nullptr;
     while (foundp != lastp) {
@@ -3409,11 +3476,12 @@ AstNodeModule* AstClassOrPackageRef::classOrPackageSkipp() const {
         if (AstNodeDType* const anodep = VN_CAST(foundp, NodeDType)) {
             foundp = anodep->skipRefOrNullp();
         }
-        if (const AstTypedef* const anodep = VN_CAST(foundp, Typedef)) {
-            foundp = anodep->subDTypep();
-        }
-        if (const AstClassRefDType* const anodep = VN_CAST(foundp, ClassRefDType)) {
-            foundp = anodep->classp();
+        if (doRefs) {
+            if (const AstTypedef* const anodep = VN_CAST(foundp, Typedef)) {
+                foundp = anodep->subDTypep();
+            } else if (const AstClassRefDType* const anodep = VN_CAST(foundp, ClassRefDType)) {
+                foundp = anodep->classp();
+            }
         }
     }
     return VN_CAST(foundp, NodeModule);
@@ -3600,9 +3668,11 @@ void AstCoverInc::dumpJson(std::ostream& str) const { dumpJsonGen(str); }
 void AstFork::dump(std::ostream& str) const {
     this->AstNodeBlock::dump(str);
     str << " [" << joinType() << "]";
+    if (immediateStart()) str << " [IMMEDIATE]";
 }
 void AstFork::dumpJson(std::ostream& str) const {
     dumpJsonStr(str, "joinType", joinType().ascii());
+    dumpJsonBoolFuncIf(str, immediateStart);
     dumpJsonGen(str);
 }
 void AstStop::dump(std::ostream& str) const {
@@ -3793,7 +3863,7 @@ void AstDelay::dumpJson(std::ostream& str) const {
 }
 
 const char* AstDisable::broken() const {
-    BROKEN_RTN((m_targetp && targetRefp()) || ((!m_targetp && !targetRefp())));
+    BROKEN_RTN(!m_targetp && !targetRefp());
     return nullptr;
 }
 void AstDisable::dump(std::ostream& str) const {

src/V3Begin.cpp

@@ -137,12 +137,9 @@ class BeginVisitor final : public VNVisitor {
             UINFO(8, "     rename to " << nodep->name());
             m_statep->userMarkChanged(nodep);
         }
-        VL_RESTORER(m_displayScope);
-        VL_RESTORER(m_namedScope);
-        VL_RESTORER(m_unnamedScope);
-        m_displayScope = "";
-        m_namedScope = "";
-        m_unnamedScope = "";
+        VL_RESTORER_CLEAR(m_displayScope);
+        VL_RESTORER_CLEAR(m_namedScope);
+        VL_RESTORER_CLEAR(m_unnamedScope);
         iterateChildren(nodep);
     }
     void visit(AstNodeProcedure* nodep) override {
@@ -163,14 +160,13 @@ class BeginVisitor final : public VNVisitor {
         // naming; so that any begin's inside the function will rename
         // inside the function.
         // Process children
-        VL_RESTORER(m_displayScope);
+        VL_RESTORER_COPY(m_displayScope);
         VL_RESTORER(m_ftaskp);
         VL_RESTORER(m_liftedp);
-        VL_RESTORER(m_namedScope);
-        VL_RESTORER(m_unnamedScope);
+        VL_RESTORER_CLEAR(m_namedScope);
+        VL_RESTORER_CLEAR(m_unnamedScope);
         m_displayScope = dot(m_displayScope, nodep->name());
-        m_namedScope = "";
-        m_unnamedScope = "";
+
         m_ftaskp = nodep;
         m_liftedp = nullptr;
         iterateChildren(nodep);
@@ -191,9 +187,9 @@ class BeginVisitor final : public VNVisitor {
     void visit(AstGenBlock* nodep) override {
         // GenBlocks were only useful in variable creation, change names and delete
         UINFO(8, "  " << nodep);
-        VL_RESTORER(m_displayScope);
-        VL_RESTORER(m_namedScope);
-        VL_RESTORER(m_unnamedScope);
+        VL_RESTORER_COPY(m_displayScope);
+        VL_RESTORER_COPY(m_namedScope);
+        VL_RESTORER_COPY(m_unnamedScope);
         UASSERT_OBJ(!m_keepBegins, nodep, "Should be able to eliminate all AstGenBlock");
         dotNames(nodep->name(), nodep->fileline(), "__BEGIN__");
         iterateAndNextNull(nodep->itemsp());
@@ -227,9 +223,9 @@ class BeginVisitor final : public VNVisitor {
     void visit(AstBegin* nodep) override {
         // Begin blocks were only useful in variable creation, change names and delete
         UINFO(8, "  " << nodep);
-        VL_RESTORER(m_displayScope);
-        VL_RESTORER(m_namedScope);
-        VL_RESTORER(m_unnamedScope);
+        VL_RESTORER_COPY(m_displayScope);
+        VL_RESTORER_COPY(m_namedScope);
+        VL_RESTORER_COPY(m_unnamedScope);
         {
             VL_RESTORER(m_keepBegins);
             m_keepBegins = false;
@@ -261,9 +257,9 @@ class BeginVisitor final : public VNVisitor {
     void visit(AstNodeBlock* nodep) override {
         // Begin/Fork blocks were only useful in variable creation, change names and delete
         UINFO(8, "  " << nodep);
-        VL_RESTORER(m_displayScope);
-        VL_RESTORER(m_namedScope);
-        VL_RESTORER(m_unnamedScope);
+        VL_RESTORER_COPY(m_displayScope);
+        VL_RESTORER_COPY(m_namedScope);
+        VL_RESTORER_COPY(m_unnamedScope);
         {
             VL_RESTORER(m_keepBegins);
             m_keepBegins = VN_IS(nodep, Fork);
@@ -451,7 +447,7 @@ class BeginRelinkVisitor final : public VNVisitorConst {
 private:
     // NODE STATE
     //  Input:
-    //   AstNodeFTask::user1p           // Node replaced, rename it
+    //   AstNodeFTask::user1p           // bool.  Node replaced, rename it
 
     // VISITORS
     void visit(AstNodeFTaskRef* nodep) override {

src/V3Broken.cpp

@@ -252,18 +252,15 @@ private:
     void visit(AstScope* nodep) override {
         VL_RESTORER(m_inScope);
         m_inScope = true;
-        VL_RESTORER(m_cFuncNames);
-        m_cFuncNames.clear();
+        VL_RESTORER_CLEAR(m_cFuncNames);
         processAndIterate(nodep);
     }
     void visit(AstNodeModule* nodep) override {
-        VL_RESTORER(m_cFuncNames);
-        m_cFuncNames.clear();
+        VL_RESTORER_CLEAR(m_cFuncNames);
         processAndIterate(nodep);
     }
     void visit(AstNodeUOrStructDType* nodep) override {
-        VL_RESTORER(m_cFuncNames);
-        m_cFuncNames.clear();
+        VL_RESTORER_CLEAR(m_cFuncNames);
         processAndIterate(nodep);
     }
     void visit(AstNodeVarRef* nodep) override {

src/V3Cast.cpp

@@ -49,7 +49,7 @@ VL_DEFINE_DEBUG_FUNCTIONS;
 class CastVisitor final : public VNVisitor {
     // NODE STATE
     // Entire netlist:
-    //   AstNode::user1()               // bool.  Indicates node is of known size
+    //   AstNode::user1()               // bool.  Node is of known size
     const VNUser1InUse m_inuser1;
 
     // STATE

src/V3Class.cpp

@@ -114,7 +114,7 @@ class ClassVisitor final : public VNVisitor {
                            classScopep->aboveScopep(), classScopep->aboveCellp()};
         packagep->addStmtsp(scopep);
         // Iterate
-        VL_RESTORER(m_prefix);
+        VL_RESTORER_CLEAR(m_prefix);
         VL_RESTORER(m_classPackagep);
         VL_RESTORER(m_classScopep);
         VL_RESTORER(m_packageScopep);
@@ -129,7 +129,7 @@ class ClassVisitor final : public VNVisitor {
     void visit(AstNodeModule* nodep) override {
         // Visit for NodeModules that are not AstClass (AstClass is-a AstNodeModule)
         // Classes are always under a Package (perhaps $unit) or a module
-        VL_RESTORER(m_prefix);
+        VL_RESTORER_CLEAR(m_prefix);
         VL_RESTORER(m_modp);
         m_modp = nodep;
         m_prefix = nodep->name() + "__03a__03a";  // ::

src/V3Clean.cpp

@@ -35,7 +35,7 @@ VL_DEFINE_DEBUG_FUNCTIONS;
 class CleanVisitor final : public VNVisitor {
     // NODE STATE
     // Entire netlist:
-    //  AstNode::user()         -> CleanState.  For this node, 0==UNKNOWN
+    //  AstNode::user1()        -> CleanState.  For this node, 0==UNKNOWN
     //  AstNode::user2()        -> bool.  True indicates widthMin has been propagated
     //  AstNodeDType::user3()   -> AstNodeDType*.  Alternative node with C size
     const VNUser1InUse m_inuser1;

src/V3Const.cpp

@@ -438,6 +438,7 @@ class ConstBitOpTreeVisitor final : public VNVisitorConst {
 
     // Traverse down to see AstConst or AstVarRef
     LeafInfo findLeaf(AstNode* nodep, bool expectConst) {
+        if (!nodep->dtypep()->skipRefp()->isIntegralOrPacked()) return LeafInfo{};
         LeafInfo info{m_lsb};
         {
             VL_RESTORER(m_leafp);
@@ -1708,8 +1709,7 @@ class ConstVisitor final : public VNVisitor {
         const V3Number num{constp, subsize, constp->num()};
         nodep->lhsp(new AstConst{constp->fileline(), num});
         VL_DO_DANGLING(pushDeletep(constp), constp);
-        UINFOTREE(9, nodep, "", "BI(EXTEND)-ou");
-        return true;
+        return false;  // input node is still valid, keep going
     }
     bool operandBiExtendConstOver(const AstNodeBiop* nodep) {
         // EQ(const{width32}, EXTEND(xx{width3})) -> constant
@@ -2069,7 +2069,7 @@ class ConstVisitor final : public VNVisitor {
         rp->rhsp(bp);
         rp->dtypeFrom(nodep);  // Upper widthMin more likely correct
         if (VN_IS(rp->lhsp(), Const) && VN_IS(rp->rhsp(), Const)) replaceConst(rp);
-        // UINFOTREE(1, nodep, "", "repAsvConst_new");
+        iterate(nodep);  // Proceed to fixed point
     }
     void replaceAsvLUp(AstNodeBiop* nodep) {
         // BIASV(BIASV(CONSTll,lr),r) -> BIASV(CONSTll,BIASV(lr,r))
@@ -2082,7 +2082,7 @@ class ConstVisitor final : public VNVisitor {
         lp->lhsp(lrp);
         lp->rhsp(rp);
         lp->dtypeFrom(nodep);  // Upper widthMin more likely correct
-        // UINFOTREE(1, nodep, "", "repAsvLUp_new");
+        iterate(nodep);  // Proceed to fixed point
     }
     void replaceAsvRUp(AstNodeBiop* nodep) {
         // BIASV(l,BIASV(CONSTrl,rr)) -> BIASV(CONSTrl,BIASV(l,rr))
@@ -2095,7 +2095,7 @@ class ConstVisitor final : public VNVisitor {
         rp->lhsp(lp);
         rp->rhsp(rrp);
         rp->dtypeFrom(nodep);  // Upper widthMin more likely correct
-        // UINFOTREE(1, nodep, "", "repAsvRUp_new");
+        iterate(nodep);  // Proceed to fixed point
     }
     void replaceAndOr(AstNodeBiop* nodep) {
         //  OR  (AND (CONSTll,lr), AND(CONSTrl==ll,rr))    -> AND (CONSTll, OR(lr,rr))
@@ -2780,9 +2780,8 @@ class ConstVisitor final : public VNVisitor {
                 streamp->dtypeSetLogicUnsized(packedp->width(), packedp->widthMin(),
                                               VSigning::UNSIGNED);
                 srcp = packedp;
-            }
-            if ((VN_IS(srcDTypep, QueueDType) || VN_IS(srcDTypep, DynArrayDType)
-                 || VN_IS(srcDTypep, UnpackArrayDType))) {
+            } else if ((VN_IS(srcDTypep, QueueDType) || VN_IS(srcDTypep, DynArrayDType)
+                        || VN_IS(srcDTypep, UnpackArrayDType))) {
                 if (VN_IS(dstDTypep, QueueDType) || VN_IS(dstDTypep, DynArrayDType)) {
                     int blockSize = 1;
                     if (const AstConst* const constp = VN_CAST(streamp->rhsp(), Const)) {
@@ -4585,6 +4584,10 @@ class ConstVisitor final : public VNVisitor {
     // Custom
     // Implied by AstIsUnbounded::numberOperate: V("AstIsUnbounded{$lhsp.castConst}", "replaceNum(nodep, 0)");
     TREEOPV("AstIsUnbounded{$lhsp.castUnbounded}", "replaceNum(nodep, 1)");
+    // Sampled value functions of a constant.
+    // $rose/$fell/$stable/$changed are lowered to $past by V3AssertPre, so they fold via AstPast
+    TREEOPV("AstSampled{$exprp.castConst}", "replaceWChild(nodep, VN_AS(nodep->exprp(), NodeExpr))");
+    TREEOPV("AstPast{$exprp.castConst, !$ticksp}", "replaceWChild(nodep, nodep->exprp())");
     // clang-format on
 
     // Possible futures:

src/V3Coverage.cpp

@@ -279,8 +279,8 @@ class CoverageVisitor final : public VNVisitor {
         const AstNodeModule* const origModp = m_modp;
         VL_RESTORER(m_modp);
         VL_RESTORER(m_state);
-        VL_RESTORER(m_exprTempNames);
-        VL_RESTORER(m_funcTemps);
+        VL_RESTORER_COPY(m_exprTempNames);
+        VL_RESTORER_COPY(m_funcTemps);
         createHandle(nodep);
         m_modp = nodep;
         m_state.m_inModOff = false;  // Haven't made top shell, so tops are real tops
@@ -294,8 +294,8 @@ class CoverageVisitor final : public VNVisitor {
     void visit(AstClass* nodep) override {
         VL_RESTORER(m_modp);
         VL_RESTORER(m_state);
-        VL_RESTORER(m_exprTempNames);
-        VL_RESTORER(m_funcTemps);
+        VL_RESTORER_COPY(m_exprTempNames);
+        VL_RESTORER_COPY(m_funcTemps);
         createHandle(nodep);
         m_modp = nodep;
         // Covergroup declarations are not executable statements; suppress line/expr/toggle
@@ -356,8 +356,8 @@ class CoverageVisitor final : public VNVisitor {
 
     void visit(AstNodeFTask* nodep) override {
         VL_RESTORER(m_ftaskp);
-        VL_RESTORER(m_exprTempNames);
-        VL_RESTORER(m_funcTemps);
+        VL_RESTORER_COPY(m_exprTempNames);
+        VL_RESTORER_COPY(m_funcTemps);
         m_ftaskp = nodep;
         if (!nodep->dpiImport()) iterateProcedure(nodep);
     }
@@ -385,8 +385,7 @@ class CoverageVisitor final : public VNVisitor {
         VL_RESTORER(m_state);
         VL_RESTORER(m_exprStmtsp);
         VL_RESTORER(m_inToggleOff);
-        // skip properties for expresison coverage
-        if (!VN_IS(nodep, Property)) m_exprStmtsp = nodep;
+        m_exprStmtsp = nodep;
         m_inToggleOff = true;
         createHandle(nodep);
         iterateChildren(nodep);
@@ -745,6 +744,11 @@ class CoverageVisitor final : public VNVisitor {
                 newCoverInc(nodep->fileline(), declp, m_beginHier + "_vlCoverageUserTrace"));
         }
     }
+    void visit(AstPropSpec* nodep) override {
+        VL_RESTORER(m_exprStmtsp);
+        m_exprStmtsp = nullptr;
+        iterateChildren(nodep);
+    }
     void visit(AstStop* nodep) override {
         UINFO(4, "  STOP: " << nodep);
         m_state.m_on = false;
@@ -762,7 +766,7 @@ class CoverageVisitor final : public VNVisitor {
     }
     void visit(AstGenBlock* nodep) override {
         // Similar to AstBegin
-        VL_RESTORER(m_beginHier);
+        VL_RESTORER_COPY(m_beginHier);
         if (nodep->name() != "") {
             m_beginHier = m_beginHier + (m_beginHier != "" ? "__DOT__" : "") + nodep->name();
         }
@@ -776,7 +780,7 @@ class CoverageVisitor final : public VNVisitor {
         // generate blocks; each point should get separate consideration.
         // (Currently ignored for line coverage, since any generate iteration
         // covers the code in that line.)
-        VL_RESTORER(m_beginHier);
+        VL_RESTORER_COPY(m_beginHier);
         VL_RESTORER(m_inToggleOff);
         VL_RESTORER(m_exprStmtsp);
         m_exprStmtsp = nodep;
@@ -874,7 +878,7 @@ class CoverageVisitor final : public VNVisitor {
         UASSERT_OBJ(m_exprs.empty(), nodep, "unexpected expression coverage garbage");
         VL_RESTORER(m_seeking);
         VL_RESTORER(m_objective);
-        VL_RESTORER(m_exprs);
+        VL_RESTORER_CLEAR(m_exprs);  // Already asserted above it's empty.
 
         m_seeking = SEEKING;
         m_objective = false;

src/V3Dfg.cpp

@@ -34,180 +34,6 @@ DfgGraph::~DfgGraph() {
     forEachVertex([&](DfgVertex& vtx) { vtx.unlinkDelete(*this); });
 }
 
-std::unique_ptr<DfgGraph> DfgGraph::clone() const {
-    // Create the new graph
-    DfgGraph* const clonep = new DfgGraph{name()};
-
-    // Map from original vertex to clone
-    std::unordered_map<const DfgVertex*, DfgVertex*> vtxp2clonep(size() * 2);
-
-    // Clone constVertices
-    for (const DfgConst& vtx : m_constVertices) {
-        DfgConst* const cp = new DfgConst{*clonep, vtx.fileline(), vtx.num()};
-        vtxp2clonep.emplace(&vtx, cp);
-    }
-    // Clone variable vertices
-    for (const DfgVertexVar& vtx : m_varVertices) {
-        const DfgVertexVar* const vp = vtx.as<DfgVertexVar>();
-        DfgVertexVar* cp = nullptr;
-
-        switch (vtx.type()) {
-        case VDfgType::VarArray: {
-            cp = new DfgVarArray{*clonep, vp->vscp()};
-            vtxp2clonep.emplace(&vtx, cp);
-            break;
-        }
-        case VDfgType::VarPacked: {
-            cp = new DfgVarPacked{*clonep, vp->vscp()};
-            vtxp2clonep.emplace(&vtx, cp);
-            break;
-        }
-        default: {
-            vtx.v3fatalSrc("Unhandled variable vertex type: " + vtx.typeName());
-            VL_UNREACHABLE;
-            break;
-        }
-        }
-
-        if (AstVarScope* const tmpForp = vp->tmpForp()) cp->tmpForp(tmpForp);
-    }
-    // Clone ast reference vertices
-    for (const DfgVertexAst& vtx : m_astVertices) {  // LCOV_EXCL_START
-        switch (vtx.type()) {
-        case VDfgType::AstRd: {
-            const DfgAstRd* const vp = vtx.as<DfgAstRd>();
-            DfgAstRd* const cp = new DfgAstRd{*clonep, vp->exprp(), vp->inSenItem(), vp->inLoop()};
-            vtxp2clonep.emplace(&vtx, cp);
-            break;
-        }
-        default: {
-            vtx.v3fatalSrc("Unhandled ast reference vertex type: " + vtx.typeName());
-            VL_UNREACHABLE;
-            break;
-        }
-        }
-    }  // LCOV_EXCL_STOP
-    // Clone operation vertices
-    for (const DfgVertex& vtx : m_opVertices) {
-        switch (vtx.type()) {
-#include "V3Dfg__gen_clone_cases.h"  // From ./astgen
-        case VDfgType::CReset: {  // LCOV_EXCL_START - No algorithm actually hits this today
-            DfgCReset* const cp = new DfgCReset{*clonep, vtx.fileline(), vtx.dtype()};
-            vtxp2clonep.emplace(&vtx, cp);
-            break;
-        }  // LCOV_EXCL_STOP
-        case VDfgType::MatchMasked: {
-            DfgMatchMasked* const cp = new DfgMatchMasked{*clonep, vtx.fileline(), vtx.dtype()};
-            vtxp2clonep.emplace(&vtx, cp);
-            break;
-        }
-        case VDfgType::Sel: {
-            DfgSel* const cp = new DfgSel{*clonep, vtx.fileline(), vtx.dtype()};
-            cp->lsb(vtx.as<DfgSel>()->lsb());
-            vtxp2clonep.emplace(&vtx, cp);
-            break;
-        }
-        case VDfgType::Rep: {
-            DfgRep* const cp = new DfgRep{*clonep, vtx.fileline(), vtx.dtype()};
-            vtxp2clonep.emplace(&vtx, cp);
-            break;
-        }
-        case VDfgType::UnitArray: {
-            DfgUnitArray* const cp = new DfgUnitArray{*clonep, vtx.fileline(), vtx.dtype()};
-            vtxp2clonep.emplace(&vtx, cp);
-            break;
-        }
-        case VDfgType::Mux: {
-            DfgMux* const cp = new DfgMux{*clonep, vtx.fileline(), vtx.dtype()};
-            vtxp2clonep.emplace(&vtx, cp);
-            break;
-        }
-        case VDfgType::SpliceArray: {
-            DfgSpliceArray* const cp = new DfgSpliceArray{*clonep, vtx.fileline(), vtx.dtype()};
-            vtxp2clonep.emplace(&vtx, cp);
-            break;
-        }
-        case VDfgType::SplicePacked: {
-            DfgSplicePacked* const cp = new DfgSplicePacked{*clonep, vtx.fileline(), vtx.dtype()};
-            vtxp2clonep.emplace(&vtx, cp);
-            break;
-        }
-        case VDfgType::Logic: {
-            vtx.v3fatalSrc("DfgLogic cannot be cloned");
-            VL_UNREACHABLE;
-            break;
-        }
-        case VDfgType::Unresolved: {
-            vtx.v3fatalSrc("DfgUnresolved cannot be cloned");
-            VL_UNREACHABLE;
-            break;
-        }
-        case VDfgType::AstRd:  // LCOV_EXCL_START
-        case VDfgType::Const:
-        case VDfgType::VarArray:
-        case VDfgType::VarPacked: {
-            vtx.v3fatalSrc("Vertex should have been handled above: " + vtx.typeName());
-            VL_UNREACHABLE;
-            break;
-        }  // LCOV_EXCL_STOP
-        }
-    }
-    UASSERT(size() == clonep->size(), "Size of clone should be the same");
-
-    // Constants have no inputs
-    // Hook up inputs of cloned variables
-    for (const DfgVertexVar& vtx : m_varVertices) {
-        DfgVertexVar* const cp = vtxp2clonep.at(&vtx)->as<DfgVertexVar>();
-        if (const DfgVertex* const srcp = vtx.srcp()) cp->srcp(vtxp2clonep.at(srcp));
-        if (const DfgVertex* const defp = vtx.defaultp()) cp->defaultp(vtxp2clonep.at(defp));
-    }
-    // Hook up inputs of cloned ast references
-    for (const DfgVertexAst& vtx : m_astVertices) {  // LCOV_EXCL_START
-        switch (vtx.type()) {
-        case VDfgType::AstRd: {
-            const DfgAstRd* const vp = vtx.as<DfgAstRd>();
-            DfgAstRd* const cp = vtxp2clonep.at(&vtx)->as<DfgAstRd>();
-            if (const DfgVertex* const srcp = vp->srcp()) cp->srcp(vtxp2clonep.at(srcp));
-            break;
-        }
-        default: {
-            vtx.v3fatalSrc("Unhandled DfgVertexAst sub type: " + vtx.typeName());
-            VL_UNREACHABLE;
-            break;
-        }
-        }
-    }  // LCOV_EXCL_STOP
-    // Hook up inputs of cloned operation vertices
-    for (const DfgVertex& vtx : m_opVertices) {
-        if (vtx.is<DfgVertexVariadic>()) {
-            switch (vtx.type()) {
-            case VDfgType::SpliceArray:
-            case VDfgType::SplicePacked: {
-                const DfgVertexSplice* const vp = vtx.as<DfgVertexSplice>();
-                DfgVertexSplice* const cp = vtxp2clonep.at(vp)->as<DfgVertexSplice>();
-                vp->foreachDriver([&](const DfgVertex& src, uint32_t lo, FileLine* flp) {
-                    cp->addDriver(vtxp2clonep.at(&src), lo, flp);
-                    return false;
-                });
-                break;
-            }
-            default: {
-                vtx.v3fatalSrc("Unhandled DfgVertexVariadic sub type: " + vtx.typeName());
-                VL_UNREACHABLE;
-                break;
-            }
-            }
-        } else {
-            DfgVertex* const cp = vtxp2clonep.at(&vtx);
-            for (size_t i = 0; i < vtx.nInputs(); ++i) {
-                cp->inputp(i, vtxp2clonep.at(vtx.inputp(i)));
-            }
-        }
-    }
-
-    return std::unique_ptr<DfgGraph>{clonep};
-}
-
 void DfgGraph::mergeGraphs(std::vector<std::unique_ptr<DfgGraph>>&& otherps) {
     if (otherps.empty()) return;
 
@@ -353,6 +179,40 @@ static void dumpDotVertex(std::ostream& os, const DfgVertex& vtx) {
         return;
     }
 
+    if (const DfgPrev* const prevVtxp = vtx.cast<DfgPrev>()) {
+        const AstVarScope* const vscp = prevVtxp->vscp();
+        os << toDotId(vtx);
+        // Begin attributes
+        os << " [";
+        // Begin 'label'
+        os << "label=\"";
+        // Name
+        os << vscp->prettyName();
+        // Address
+        os << '\n' << cvtToHex(prevVtxp);
+        // Type and fanout
+        os << '\n';
+        prevVtxp->dtype().astDtypep()->dumpSmall(os);
+        os << " / F" << prevVtxp->fanout();
+        // End 'label'
+        os << '"';
+        // Shape
+        if (prevVtxp->isPacked()) {
+            os << ", shape=box";
+        } else if (prevVtxp->isArray()) {
+            os << ", shape=box3d";
+        } else {
+            prevVtxp->v3fatalSrc("Unhandled variable type");
+        }
+        // Color
+        const char* const colorp = "mediumorchid1";  // Purple
+        os << ", style=filled";
+        os << ", fillcolor=\"" << colorp << "\"";
+        // End attributes
+        os << "]\n";
+        return;
+    }
+
     if (const DfgConst* const constVtxp = vtx.cast<DfgConst>()) {
         const V3Number& num = constVtxp->num();
 
@@ -620,6 +480,12 @@ DfgVertex::DfgVertex(DfgGraph& dfg, VDfgType type, FileLine* flp, const DfgDataT
     dfg.addVertex(*this);
 }
 
+bool DfgVertex::unsafe() const {
+    if (is<DfgMux>()) return true;
+    if (is<DfgArraySel>()) return !as<DfgArraySel>()->bitp()->is<DfgConst>();
+    return false;
+}
+
 void DfgVertex::typeCheck(const DfgGraph& dfg) const {
 
 #define CHECK(cond, msg) \
@@ -647,6 +513,10 @@ void DfgVertex::typeCheck(const DfgGraph& dfg) const {
         CHECK(!v.srcp() || v.srcp()->dtype() == v.dtype(), "'srcp' should match");
         return;
     }
+    case VDfgType::Prev: {
+        CHECK(isPacked() || isArray(), "Should be Packed or Array type");
+        return;
+    }
     case VDfgType::SpliceArray:
     case VDfgType::SplicePacked: {
         const DfgVertexSplice& v = *as<DfgVertexSplice>();

src/V3Dfg.h

@@ -195,6 +195,8 @@ public:
         UASSERT_OBJ(m_dtype.isPacked(), this, "Non packed vertex has no 'width'");
         return m_dtype.size();
     }
+    // Has terminating side-effect
+    bool unsafe() const;
 
     // Type check vertex (for debugging)
     void typeCheck(const DfgGraph& dfg) const;
@@ -485,9 +487,6 @@ public:
         for (const DfgVertex& vtx : m_opVertices) f(vtx);
     }
 
-    // Return an identical, independent copy of this graph. Vertex and edge order might differ.
-    std::unique_ptr<DfgGraph> clone() const VL_MT_DISABLED;
-
     // Merge contents of other graphs into this graph. Deletes the other graphs.
     // DfgVertexVar instances representing the same Ast variable are unified.
     void mergeGraphs(std::vector<std::unique_ptr<DfgGraph>>&& otherps) VL_MT_DISABLED;
@@ -817,6 +816,7 @@ bool DfgVertex::isCheaperThanLoad() const {
     if (is<DfgConst>()) return true;
     // Variables
     if (is<DfgVertexVar>()) return true;
+    if (is<DfgPrev>()) return true;
     // Array sels are just address computation, but the address itself can be expensive
     if (const DfgArraySel* aselp = cast<DfgArraySel>()) {
         if (aselp->bitp()->is<DfgMatchMasked>()) return false;
@@ -830,6 +830,13 @@ bool DfgVertex::isCheaperThanLoad() const {
         const uint32_t msb = lsb + selp->width() - 1;
         return VL_BITWORD_E(msb) == VL_BITWORD_E(lsb);
     }
+    // Replication of a single cheap bit. Each word of the result is the same
+    // mask computed by negating that bit, so recomputing it at each use costs
+    // no more than the load it replaces.
+    if (const DfgRep* const repp = cast<DfgRep>()) {
+        const DfgVertex* const srcp = repp->srcp();
+        return srcp->width() == 1 && srcp->isCheaperThanLoad();
+    }
     // Zero extend of a cheap vertex - Extend(_) was converted to Concat(0, _)
     if (const DfgConcat* const catp = cast<DfgConcat>()) {
         if (catp->width() > VL_QUADSIZE) return false;

src/V3DfgContext.h

@@ -100,10 +100,10 @@ class V3DfgBreakCyclesContext final : public V3DfgSubContext {
 public:
     // STATE
     VDouble0 m_nFixed;  // Number of graphs that became acyclic
-    VDouble0 m_nImproved;  // Number of graphs that were imporoved but still cyclic
+    VDouble0 m_nImproved;  // Number of graphs that were improved but still cyclic
     VDouble0 m_nUnchanged;  // Number of graphs that were left unchanged
-    VDouble0 m_nTrivial;  // Number of graphs that were not changed
     VDouble0 m_nImprovements;  // Number of changes made to graphs
+    VDouble0 m_nPrevInserted;  // Number of Prev vertices inserted
 
 private:
     V3DfgBreakCyclesContext()
@@ -112,8 +112,8 @@ private:
         addStat("made acyclic", m_nFixed);
         addStat("improved", m_nImproved);
         addStat("left unchanged", m_nUnchanged);
-        addStat("trivial", m_nTrivial);
         addStat("changes applied", m_nImprovements);
+        addStat("prev vertices inserted", m_nPrevInserted);
     }
 };
 class V3DfgCseContext final : public V3DfgSubContext {

src/V3DfgCse.cpp

@@ -55,6 +55,7 @@ class V3DfgCse final {
         case VDfgType::CReset:
         case VDfgType::VarArray:
         case VDfgType::VarPacked:
+        case VDfgType::Prev:
         case VDfgType::AstRd:  // LCOV_EXCL_STOP
             vtx.v3fatalSrc("Hash should have been pre-computed");
 
@@ -173,6 +174,7 @@ class V3DfgCse final {
         // Special vertices
         case VDfgType::Const: return a.as<DfgConst>()->num().isCaseEq(b.as<DfgConst>()->num());
         case VDfgType::CReset: return false;
+        case VDfgType::Prev: return false;
 
         case VDfgType::VarArray:
         case VDfgType::VarPacked:  // CSE does not combine variables
@@ -307,9 +309,9 @@ class V3DfgCse final {
         for (const DfgVertexVar& vtx : dfg.varVertices()) m_hashCache[vtx] = V3Hash{++varHash};
         // Pre-hash Ast references, these are all unique like variables
         for (const DfgVertexAst& vtx : dfg.astVertices()) m_hashCache[vtx] = V3Hash{++varHash};
-        // Pre-hash CReset vertices, these are all unique
+        // Pre-hash CReset and Prev vertices, these are all unique
         for (const DfgVertex& vtx : dfg.opVertices()) {
-            if (vtx.is<DfgCReset>()) m_hashCache[vtx] = V3Hash{++varHash};
+            if (vtx.is<DfgCReset>() || vtx.is<DfgPrev>()) m_hashCache[vtx] = V3Hash{++varHash};
         }
 
         // Similarly pre-hash constants for speed. While we don't combine constants, we do want

src/V3DfgDfgToAst.cpp

@@ -224,6 +224,10 @@ class DfgToAstVisitor final : DfgVisitor {
         m_resultp = new AstVarRef{vtxp->fileline(), vtxp->vscp(), VAccess::READ};
     }
 
+    void visit(DfgPrev* vtxp) override {
+        m_resultp = new AstVarRef{vtxp->fileline(), vtxp->vscp(), VAccess::READ};
+    }
+
     void visit(DfgConst* vtxp) override {  //
         m_resultp = new AstConst{vtxp->fileline(), vtxp->num()};
     }

src/V3DfgOptimizer.cpp

@@ -39,7 +39,8 @@ class DataflowOptimize final {
     // - bit2: Read by logic in same module/netlist not represented in DFG
     // - bit3: Written by logic in same module/netlist not represented in DFG
     // - bit4: Has READWRITE references
-    // - bit31-5: Reference count, how many DfgVertexVar represent this variable
+    // - bit5: Has DfgPrev instance
+    // - bit31-6: Reference count, how many DfgVertexVar represent this variable
     //
     // AstNode::user2/user3/user4 can be used by various DFG algorithms
     const VNUser1InUse m_user1InUse;
@@ -116,69 +117,44 @@ class DataflowOptimize final {
         V3DfgPasses::synthesize(dfg, m_ctx);
         endOfStage("synthesize", dfg, {});
 
-        // Extract the cyclic sub-graphs. We do this because a lot of the optimizations assume a
-        // DAG, and large, mostly acyclic graphs could not be optimized due to the presence of
-        // small cycles.
-        std::vector<std::unique_ptr<DfgGraph>> cyclicComps = dfg.extractCyclicComponents("cyclic");
-        endOfStage("extractCyclic", dfg, cyclicComps);
-
-        // Attempt to convert cyclic components into acyclic ones
-        std::vector<std::unique_ptr<DfgGraph>> madeAcyclicComponents;
-        if (v3Global.opt.fDfgBreakCycles()) {
-            for (auto it = cyclicComps.begin(); it != cyclicComps.end();) {
-                auto result = V3DfgPasses::breakCycles(**it, m_ctx);
-                if (!result.first) {
-                    // No improvement, moving on.
-                    ++it;
-                } else if (!result.second) {
-                    // Improved, but still cyclic. Replace the original cyclic component.
-                    *it = std::move(result.first);
-                    ++it;
-                } else {
-                    // Result became acyclic. Move to madeAcyclicComponents, delete original.
-                    madeAcyclicComponents.emplace_back(std::move(result.first));
-                    it = cyclicComps.erase(it);
-                }
-            }
+        // Extract the cyclic sub-graphs, so breakCycles can operate on small graphs,
+        // make all of them acyclic, then merge them back to the main graph
+        {
+            std::vector<std::unique_ptr<DfgGraph>> comps = dfg.extractCyclicComponents("cyclic");
+            for (const auto& cp : comps) V3DfgPasses::breakCycles(*cp, m_ctx);
+            dfg.mergeGraphs(std::move(comps));
+            endOfStage("breakCycles", dfg, {});
         }
-        // Merge those that were made acyclic back to the graph, this enables optimizing more
-        dfg.mergeGraphs(std::move(madeAcyclicComponents));
-        endOfStage("breakCycles", dfg, cyclicComps);
 
-        // Remove redundant selects
-        V3DfgPasses::removeSelects(dfg, m_ctx.m_removeSelectsContext);
-        for (std::unique_ptr<DfgGraph>& compp : cyclicComps) {
-            V3DfgPasses::removeSelects(*compp, m_ctx.m_removeSelectsContext);
-        }
-        endOfStage("removeSelects", dfg, cyclicComps);
-
-        // Split the acyclic DFG into [weakly] connected components
-        std::vector<std::unique_ptr<DfgGraph>> acyclicComps = dfg.splitIntoComponents("acyclic");
+        // Split the now entirely acyclic DFG into [weakly] connected components
+        std::vector<std::unique_ptr<DfgGraph>> comps = dfg.splitIntoComponents("acyclic");
         UASSERT(dfg.size() == 0, "DfgGraph should have become empty");
-        endOfStage("splitAcyclic", dfg, acyclicComps);
+        endOfStage("splitAcyclic", dfg, comps);
 
-        // Optimize each acyclic component
-        for (auto& cp : acyclicComps) V3DfgPasses::inlineVars(*cp);
-        endOfStage("inlineVars", dfg, acyclicComps);
-        for (auto& cp : acyclicComps) V3DfgPasses::cse(*cp, m_ctx.m_cseContext0);
-        endOfStage("cse0", dfg, acyclicComps);
-        for (auto& cp : acyclicComps) V3DfgPasses::binToOneHot(*cp, m_ctx.m_binToOneHotContext);
-        endOfStage("binToOneHot", dfg, acyclicComps);
-        for (auto& cp : acyclicComps) V3DfgPasses::peephole(*cp, m_ctx.m_peepholeContext);
-        endOfStage("peephole", dfg, acyclicComps);
-        // Accumulate patterns for reporting
-        if (v3Global.opt.dumpDfgPatterns()) {
-            V3DfgPasses::dumpPatterns(acyclicComps);
-            endOfStage("dumpPatterns");
+        // Main pass pipeline - optimize each acyclic component
+        {
+            for (auto& cp : comps) V3DfgPasses::removeSelects(*cp, m_ctx.m_removeSelectsContext);
+            endOfStage("removeSelects", dfg, comps);
+            for (const auto& cp : comps) V3DfgPasses::inlineVars(*cp);
+            endOfStage("inlineVars", dfg, comps);
+            for (auto& cp : comps) V3DfgPasses::cse(*cp, m_ctx.m_cseContext0);
+            endOfStage("cse0", dfg, comps);
+            for (auto& cp : comps) V3DfgPasses::binToOneHot(*cp, m_ctx.m_binToOneHotContext);
+            endOfStage("binToOneHot", dfg, comps);
+            for (auto& cp : comps) V3DfgPasses::peephole(*cp, m_ctx.m_peepholeContext);
+            endOfStage("peephole", dfg, comps);
+
+            // Accumulate patterns for reporting
+            if (v3Global.opt.dumpDfgPatterns()) V3DfgPasses::dumpPatterns(comps);
+
+            for (auto& cp : comps) V3DfgPasses::pushDownSels(*cp, m_ctx.m_pushDownSelsContext);
+            endOfStage("pushDownSels", dfg, comps);
+            for (auto& cp : comps) V3DfgPasses::cse(*cp, m_ctx.m_cseContext1);
+            endOfStage("cse1", dfg, comps);
         }
-        for (auto& cp : acyclicComps) V3DfgPasses::pushDownSels(*cp, m_ctx.m_pushDownSelsContext);
-        endOfStage("pushDownSels", dfg, acyclicComps);
-        for (auto& cp : acyclicComps) V3DfgPasses::cse(*cp, m_ctx.m_cseContext1);
-        endOfStage("cse1", dfg, acyclicComps);
 
-        // Merge everything back under the main DFG
-        dfg.mergeGraphs(std::move(acyclicComps));
-        dfg.mergeGraphs(std::move(cyclicComps));
+        // Merge everything back under the main graph
+        dfg.mergeGraphs(std::move(comps));
         endOfStage("optimized", dfg, {});
 
         // Regularize the graph after merging it all back together so all

src/V3DfgPasses.cpp

@@ -78,7 +78,13 @@ void V3DfgPasses::removeUnobservable(DfgGraph& dfg, V3DfgContext& dfgCtx) {
                             && !vVtxp->hasExtWrRefs()  //
                             && !vVtxp->hasModWrRefs();
         VL_DO_DANGLING(vVtxp->unlinkDelete(dfg), vVtxp);
-        if (srcp) VL_DO_DANGLING(srcp->unlinkDelete(dfg), srcp);
+        if (srcp) {
+            srcp->foreachSource([&](DfgVertex& src) {
+                src.as<DfgLogic>()->setDrivesUnusedVars();
+                return false;
+            });
+            VL_DO_DANGLING(srcp->unlinkDelete(dfg), srcp);
+        }
         if (delAst) {
             VL_DO_DANGLING(vscp->unlinkFrBack()->deleteTree(), vscp);
             ++ctx.m_varsDeleted;

src/V3DfgPasses.h

@@ -43,15 +43,10 @@ void removeUnobservable(DfgGraph&, V3DfgContext&) VL_MT_DISABLED;
 void synthesize(DfgGraph&, V3DfgContext&) VL_MT_DISABLED;
 // Remove redundant selects
 void removeSelects(DfgGraph& dfg, V3DfgRemoveSelectsContext& ctx) VL_MT_DISABLED;
-// Attempt to make the given cyclic graph into an acyclic, or "less cyclic"
-// equivalent. If the returned pointer is null, then no improvement was
-// possible on the input graph. Otherwise the returned graph is an improvement
-// on the input graph, with at least some cycles eliminated. The returned
-// graph is always independent of the original. If an imporoved graph is
-// returned, then the returned 'bool' flag indicated if the returned graph is
-// acyclic (flag 'true'), or still cyclic (flag 'false').
-std::pair<std::unique_ptr<DfgGraph>, bool>  //
-breakCycles(const DfgGraph&, V3DfgContext&) VL_MT_DISABLED;
+// Make the given cyclic graph into an acyclic one, by tracing drivers, and
+// if that is unsuccessful, by inserting Prev vertices. The given graph will
+// always become acyclic after this pass.
+void breakCycles(DfgGraph&, V3DfgContext&) VL_MT_DISABLED;
 // Construct binary to oneHot decoders
 void binToOneHot(DfgGraph&, V3DfgBinToOneHotContext&) VL_MT_DISABLED;
 // Common subexpression elimination

src/V3DfgPeephole.cpp

@@ -266,6 +266,8 @@ class V3DfgPeephole final : public DfgVisitor {
     void deleteVertex(DfgVertex* vtxp) {
         UASSERT_OBJ(!m_vInfo[vtxp].m_workListIndex, vtxp, "Deleted Vertex is in work list");
         UASSERT_OBJ(!vtxp->hasSinks(), vtxp, "Should not delete used vertex");
+        const DfgVertexVar* const varp = vtxp->cast<DfgVertexVar>();
+        UASSERT_OBJ(!varp || !varp->hasPrev(), vtxp, "Deleting variable consumed via DfgPrev");
 
         // Invalidate cache entry
         m_cache.invalidate(vtxp);
@@ -293,7 +295,6 @@ class V3DfgPeephole final : public DfgVisitor {
         // This pass only removes variables that are either not driven in this graph,
         // or are not observable outside the graph. If there is also no external write
         // to the variable and no references in other graph then delete the Ast var too.
-        const DfgVertexVar* const varp = vtxp->cast<DfgVertexVar>();
         if (varp && !varp->isVolatile() && !varp->hasDfgRefs()) {
             m_ctx.m_deleteps.push_back(varp->vscp());
             VL_DO_DANGLING(vtxp->unlinkDelete(m_dfg), vtxp);
@@ -2269,7 +2270,7 @@ class V3DfgPeephole final : public DfgVisitor {
     }
 
     void visit(DfgLogAnd* const vtxp) override {
-        if (binary(vtxp)) return;
+        if (binary(vtxp) || vtxp->rhsp()->unsafe()) return;
 
         DfgVertex* const lhsp = vtxp->lhsp();
         DfgVertex* const rhsp = vtxp->rhsp();
@@ -2287,11 +2288,11 @@ class V3DfgPeephole final : public DfgVisitor {
     }
 
     void visit(DfgLogIf* const vtxp) override {
-        if (binary(vtxp)) return;
+        if (binary(vtxp) || vtxp->rhsp()->unsafe()) return;
     }
 
     void visit(DfgLogOr* const vtxp) override {
-        if (binary(vtxp)) return;
+        if (binary(vtxp) || vtxp->rhsp()->unsafe()) return;
 
         DfgVertex* const lhsp = vtxp->lhsp();
         DfgVertex* const rhsp = vtxp->rhsp();
@@ -2548,7 +2549,13 @@ class V3DfgPeephole final : public DfgVisitor {
         if (DfgShiftL* const lShiftLp = lhsp->cast<DfgShiftL>()) {
             if (!lShiftLp->hasMultipleSinks() && rhsp->dtype() == lShiftLp->rhsp()->dtype()) {
                 APPLYING(REPLACE_SHIFTL_SHIFTL) {
-                    DfgAdd* const addp = make<DfgAdd>(rhsp, rhsp, lShiftLp->rhsp());
+                    // Fold '(a << b) << c' to 'a << (b + c)'.  Compute 'b + c'
+                    // one bit wider than the amounts so it cannot overflow.
+                    FileLine* const flp = vtxp->fileline();
+                    const DfgDataType& sumDType = DfgDataType::packed(rhsp->width() + 1);
+                    DfgVertex* const bp = make<DfgExtend>(flp, sumDType, lShiftLp->rhsp());
+                    DfgVertex* const cp = make<DfgExtend>(flp, sumDType, rhsp);
+                    DfgAdd* const addp = make<DfgAdd>(flp, sumDType, bp, cp);
                     replace(make<DfgShiftL>(vtxp, lShiftLp->lhsp(), addp));
                     return;
                 }
@@ -2637,7 +2644,13 @@ class V3DfgPeephole final : public DfgVisitor {
         if (DfgShiftR* const lShiftRp = lhsp->cast<DfgShiftR>()) {
             if (!lShiftRp->hasMultipleSinks() && rhsp->dtype() == lShiftRp->rhsp()->dtype()) {
                 APPLYING(REPLACE_SHIFTR_SHIFTR) {
-                    DfgAdd* const addp = make<DfgAdd>(rhsp, rhsp, lShiftRp->rhsp());
+                    // Fold '(a >> b) >> c' to 'a >> (b + c)'.  Compute 'b + c'
+                    // one bit wider than the amounts so it cannot overflow.
+                    FileLine* const flp = vtxp->fileline();
+                    const DfgDataType& sumDType = DfgDataType::packed(rhsp->width() + 1);
+                    DfgVertex* const bp = make<DfgExtend>(flp, sumDType, lShiftRp->rhsp());
+                    DfgVertex* const cp = make<DfgExtend>(flp, sumDType, rhsp);
+                    DfgAdd* const addp = make<DfgAdd>(flp, sumDType, bp, cp);
                     replace(make<DfgShiftR>(vtxp, lShiftRp->lhsp(), addp));
                     return;
                 }
@@ -2890,13 +2903,13 @@ class V3DfgPeephole final : public DfgVisitor {
         }
 
         if (vtxp->dtype() == m_bitDType) {
-            if (isSame(condp, thenp)) {  // a ? a : b becomes a | b
+            if (isSame(condp, thenp) && !elsep->unsafe()) {  // a ? a : b becomes a | b
                 APPLYING(REPLACE_COND_WITH_THEN_BRANCH_COND) {
                     replace(make<DfgOr>(vtxp, condp, elsep));
                     return;
                 }
             }
-            if (isSame(condp, elsep)) {  // a ? b : a becomes a & b
+            if (isSame(condp, elsep) && !thenp->unsafe()) {  // a ? b : a becomes a & b
                 APPLYING(REPLACE_COND_WITH_ELSE_BRANCH_COND) {
                     replace(make<DfgAnd>(vtxp, condp, thenp));
                     return;
@@ -2905,28 +2918,28 @@ class V3DfgPeephole final : public DfgVisitor {
         }
 
         if (vtxp->width() <= VL_QUADSIZE) {
-            if (isZero(thenp)) {  // a ? 0 : b becomes ~a & b
+            if (isZero(thenp) && !elsep->unsafe()) {  // a ? 0 : b becomes ~a & b
                 APPLYING(REPLACE_COND_WITH_THEN_BRANCH_ZERO) {
                     DfgVertex* const maskp = replicate(vtxp, make<DfgNot>(condp, condp));
                     replace(make<DfgAnd>(vtxp, maskp, elsep));
                     return;
                 }
             }
-            if (isOnes(thenp)) {  // a ? 1 : b becomes a | b
+            if (isOnes(thenp) && !elsep->unsafe()) {  // a ? 1 : b becomes a | b
                 APPLYING(REPLACE_COND_WITH_THEN_BRANCH_ONES) {
                     DfgVertex* const maskp = replicate(vtxp, condp);
                     replace(make<DfgOr>(vtxp, maskp, elsep));
                     return;
                 }
             }
-            if (isZero(elsep)) {  // a ? b : 0 becomes a & b
+            if (isZero(elsep) && !thenp->unsafe()) {  // a ? b : 0 becomes a & b
                 APPLYING(REPLACE_COND_WITH_ELSE_BRANCH_ZERO) {
                     DfgVertex* const maskp = replicate(vtxp, condp);
                     replace(make<DfgAnd>(vtxp, maskp, thenp));
                     return;
                 }
             }
-            if (isOnes(elsep)) {  // a ? b : 1 becomes ~a | b
+            if (isOnes(elsep) && !thenp->unsafe()) {  // a ? b : 1 becomes ~a | b
                 APPLYING(REPLACE_COND_WITH_ELSE_BRANCH_ONES) {
                     DfgVertex* const maskp = replicate(vtxp, make<DfgNot>(condp, condp));
                     replace(make<DfgOr>(vtxp, maskp, thenp));
@@ -2935,7 +2948,8 @@ class V3DfgPeephole final : public DfgVisitor {
             }
 
             if (DfgOr* const tOrp = thenp->cast<DfgOr>()) {
-                if (isSame(tOrp->lhsp(), elsep)) {  // a ? b | c : b becomes b | (a & c)
+                if (isSame(tOrp->lhsp(), elsep)
+                    && !tOrp->rhsp()->unsafe()) {  // a ? b | c : b becomes b | (a & c)
                     APPLYING(REPLACE_COND_THEN_OR_LHS) {
                         DfgVertex* const maskp = replicate(vtxp, condp);
                         DfgAnd* const andp = make<DfgAnd>(vtxp, maskp, tOrp->rhsp());
@@ -2943,7 +2957,8 @@ class V3DfgPeephole final : public DfgVisitor {
                         return;
                     }
                 }
-                if (isSame(tOrp->rhsp(), elsep)) {  // a ? b | c : c becomes c | (a & b)
+                if (isSame(tOrp->rhsp(), elsep)
+                    && !tOrp->lhsp()->unsafe()) {  // a ? b | c : c becomes c | (a & b)
                     APPLYING(REPLACE_COND_THEN_OR_RHS) {
                         DfgVertex* const maskp = replicate(vtxp, condp);
                         DfgAnd* const andp = make<DfgAnd>(vtxp, maskp, tOrp->lhsp());

src/V3DfgRegularize.cpp

@@ -56,16 +56,6 @@ class DfgRegularize final {
         }
     }
 
-    std::unordered_set<const DfgVertexVar*> gatherCyclicVariables() {
-        DfgUserMap<uint64_t> vtx2Scc = m_dfg.makeUserMap<uint64_t>();
-        V3DfgPasses::colorStronglyConnectedComponents(m_dfg, vtx2Scc);
-        std::unordered_set<const DfgVertexVar*> circularVariables;
-        for (const DfgVertexVar& vtx : m_dfg.varVertices()) {
-            if (vtx2Scc[vtx]) circularVariables.emplace(&vtx);
-        }
-        return circularVariables;
-    }
-
     static bool isUnused(const DfgVertex& vtx) {
         if (vtx.hasSinks()) return false;
         if (const DfgVertexVar* const varp = vtx.cast<DfgVertexVar>()) {
@@ -73,6 +63,7 @@ class DfgRegularize final {
             UASSERT_OBJ(!varp->hasDfgRefs(), varp, "Should not have refs in other DfgGraph");
             if (varp->hasModWrRefs()) return false;
             if (varp->hasExtRefs()) return false;
+            if (varp->hasPrev()) return false;
         }
         return true;
     }
@@ -87,6 +78,9 @@ class DfgRegularize final {
                     &aVtx, "Mismatched vertices");
         UASSERT_OBJ(!aVtx.is<DfgVertexVar>(), &aVtx, "Should be an operation vertex");
 
+        // Prev is just a variable reference
+        if (aVtx.is<DfgPrev>()) return false;
+
         if (bVtx.hasMultipleSinks()) {
             // Add a temporary if it's cheaper to store and load from memory than recompute
             if (!aVtx.isCheaperThanLoad()) return true;
@@ -119,10 +113,6 @@ class DfgRegularize final {
     }
 
     void eliminateVars() {
-        // Although we could eliminate some circular variables, doing so would
-        // make UNOPTFLAT traces fairly usesless, so we will not do so.
-        const std::unordered_set<const DfgVertexVar*> circularVariables = gatherCyclicVariables();
-
         // Worklist based algoritm
         DfgWorklist workList{m_dfg};
 
@@ -141,7 +131,7 @@ class DfgRegularize final {
             });
             // Delete corresponsing Ast variable at the end
             if (const DfgVertexVar* const varp = vtx.cast<DfgVertexVar>()) {
-                m_ctx.m_deleteps.push_back(varp->vscp());
+                if (!varp->hasPrev()) m_ctx.m_deleteps.push_back(varp->vscp());
             }
             // Remove the unused vertex
             vtx.unlinkDelete(m_dfg);
@@ -173,7 +163,7 @@ class DfgRegularize final {
             UASSERT_OBJ(!varp->hasDfgRefs(), varp, "Should not have refs in other DfgGraph");
 
             // Do not eliminate circular variables - need to preserve UNOPTFLAT traces
-            if (circularVariables.count(varp)) return;
+            if (varp->hasPrev()) return;
 
             // Do not inline if partially driven (the partial driver network can't be fed into
             // arbitrary logic. TODO: we should peeophole these away entirely)

src/V3DfgSynthesize.cpp

@@ -2005,6 +2005,11 @@ static void dfgSelectLogicForSynthesis(DfgGraph& dfg) {
     for (DfgVertex& vtx : dfg.opVertices()) {
         DfgLogic* const logicp = vtx.cast<DfgLogic>();
         if (!logicp) continue;
+        // If drives an unused variable, synthesize it so the partial logic can be removed
+        if (logicp->drivesUnusedVars()) {
+            worklist.push_front(*logicp);
+            continue;
+        }
         // Blocks corresponding to continuous assignments
         if (logicp->nodep()->keyword() == VAlwaysKwd::CONT_ASSIGN) {
             worklist.push_front(*logicp);
@@ -2016,10 +2021,8 @@ static void dfgSelectLogicForSynthesis(DfgGraph& dfg) {
             worklist.push_front(*logicp);
             continue;
         }
-        // Simple blocks driving exactly 1 variable, e.g if (rst) a = b else a = c;
-        if (!logicp->hasMultipleSinks() && cfg.nBlocks() <= 4 && cfg.nEdges() <= 4) {
-            worklist.push_front(*logicp);
-        }
+        // Blocks driving exactly 1 variable
+        if (!logicp->hasMultipleSinks()) worklist.push_front(*logicp);
     }
 
     // Now expand to cover all logic driving the same set of variables and mark

src/V3DfgVertices.h

@@ -62,8 +62,8 @@ protected:
                     *DfgDataType::fromAst(vscp->varp()->dtypep())}
         , m_vscp{vscp} {
         // Increment reference count
-        m_vscp->user1(m_vscp->user1() + 0x20);
-        UASSERT_OBJ((m_vscp->user1() >> 5) > 0, m_vscp, "Reference count overflow");
+        m_vscp->user1(m_vscp->user1() + 0x40);
+        UASSERT_OBJ((m_vscp->user1() >> 6) > 0, m_vscp, "Reference count overflow");
         // Allocate sources
         newInput();
         newInput();
@@ -72,8 +72,8 @@ protected:
 public:
     ~DfgVertexVar() {
         // Decrement reference count
-        m_vscp->user1(m_vscp->user1() - 0x20);
-        UASSERT_OBJ((m_vscp->user1() >> 5) >= 0, m_vscp, "Reference count underflow");
+        m_vscp->user1(m_vscp->user1() - 0x40);
+        UASSERT_OBJ((m_vscp->user1() >> 6) >= 0, m_vscp, "Reference count underflow");
     }
     ASTGEN_MEMBERS_DfgVertexVar;
 
@@ -87,7 +87,6 @@ public:
     std::string srcName(size_t idx) const override final { return idx ? "defaultp" : "srcp"; }
 
     // The Ast variable this vertex representess
-    // AstVar* varp() const { return m_varp; }
     AstVarScope* vscp() const { return m_vscp; }
 
     // If this is a temporary, the Ast variable it stands for,  or same as
@@ -100,7 +99,7 @@ public:
     void driverFileLine(FileLine* flp) { m_driverFileLine = flp; }
 
     // Variable referenced from other DFG in the same module/netlist
-    bool hasDfgRefs() const { return m_vscp->user1() >> 6; }  // I.e.: (nodep()->user1() >> 5) > 1
+    bool hasDfgRefs() const { return m_vscp->user1() >> 7; }  // I.e.: (nodep()->user1() >> 6) > 1
 
     // Variable referenced from Ast code in the same module/netlist
     static bool hasModWrRefs(const AstVarScope* nodep) { return nodep->user1() & 0x08; }
@@ -121,8 +120,15 @@ public:
     static bool hasRWRefs(const AstVarScope* nodep) { return nodep->user1() & 0x10; }
     static void setHasRWRefs(AstVarScope* nodep) { nodep->user1(nodep->user1() | 0x10); }
 
-    // True iff the value of this variable is read outside this DfgGraph
+    // There exists a DfgPrev vertex for this variable
+    static bool hasPrev(const AstVarScope* nodep) { return nodep->user1() & 0x20; }
+    bool hasPrev() const { return hasPrev(m_vscp); }
+
+    // True iff this variable is consumed without an explicit sink: its value is read outside
+    // this DfgGraph, or a DfgPrev reads it within this graph.
     bool isObserved() const {
+        // A DfgPrev reads this variable
+        if (hasPrev()) return true;
         // A DfgVarVertex is written in exactly one DfgGraph, and might be read in an arbitrary
         // number of other DfgGraphs. If it's driven in this DfgGraph, it's read in others.
         if (hasDfgRefs()) return srcp() || defaultp();
@@ -162,6 +168,33 @@ public:
     ASTGEN_MEMBERS_DfgVarPacked;
 };
 
+class DfgPrev final : public DfgVertex {
+    // Previous value of variable, before any updates made in this graph.
+    // Used to break combinational cycles.
+    friend class DfgVertex;
+    friend class DfgVisitor;
+
+    AstVarScope* const m_vscp;  // The AstVarScope associated with this vertex (not owned)
+
+public:
+    DfgPrev(DfgGraph& dfg, AstVarScope* vscp)
+        : DfgVertex{dfg, dfgType(), vscp->varp()->fileline(),
+                    *DfgDataType::fromAst(vscp->varp()->dtypep())}
+        , m_vscp{vscp} {
+        UASSERT_OBJ(!DfgVertexVar::hasPrev(vscp), vscp, "Variable already has a DfgPrev");
+        m_vscp->user1(m_vscp->user1() | 0x20);  // Mark having a DfgPrev
+    }
+    ~DfgPrev() {
+        m_vscp->user1(m_vscp->user1() & ~0x20);  // Unmark having a DfgPrev
+    }
+    ASTGEN_MEMBERS_DfgPrev;
+
+    // The Ast variable this vertex representess
+    AstVarScope* vscp() const { return m_vscp; }
+
+    std::string srcName(size_t) const override final { return ""; }
+};
+
 //------------------------------------------------------------------------------
 // Ast reference vertices
 
@@ -512,6 +545,7 @@ class DfgLogic final : public DfgVertexVariadic {
     AstScope* const m_scopep;  // The AstScope m_nodep is under, iff scoped
     const std::unique_ptr<CfgGraph> m_cfgp;
     std::vector<DfgVertex*> m_synth;  // Vertices this logic was synthesized into
+    bool m_drivesUnusedVars = false;  // Logic drives unused variables
     bool m_selectedForSynthesis = false;  // Logic selected for synthesis
     bool m_nonSynthesizable = false;  // Logic is not synthesizeable (by DfgSynthesis)
     bool m_reverted = false;  // Logic was synthesized (in part if non-synthesizable) then reverted
@@ -538,6 +572,8 @@ public:
     const CfgGraph& cfg() const { return *m_cfgp; }
     std::vector<DfgVertex*>& synth() { return m_synth; }
     const std::vector<DfgVertex*>& synth() const { return m_synth; }
+    bool drivesUnusedVars() const { return m_drivesUnusedVars; }
+    void setDrivesUnusedVars() { m_drivesUnusedVars = true; }
     bool selectedForSynthesis() const { return m_selectedForSynthesis; }
     void setSelectedForSynthesis() { m_selectedForSynthesis = true; }
     bool nonSynthesizable() const { return m_nonSynthesizable; }

src/V3EmitCBase.cpp

@@ -137,6 +137,10 @@ void EmitCBaseVisitorConst::emitCDefaultConstructor(const AstNodeModule* const m
 void EmitCBaseVisitorConst::emitCFuncHeader(const AstCFunc* funcp, const AstNodeModule* modp,
                                             bool withScope) {
     if (funcp->slow()) putns(funcp, "VL_ATTR_COLD ");
+    if (funcp->dpiCDeclOverride()) {
+        putns(funcp, funcp->dpiCDecl() + ";\n");
+        return;
+    }
     if (!funcp->isDestructor()) {
         putns(funcp, funcp->rtnTypeVoid());
         puts(" ");

src/V3EmitCFunc.cpp

@@ -485,7 +485,7 @@ void EmitCFunc::emitVarReset(const string& prefix, AstVar* varp, bool constructi
             const auto& mapr = initarp->map();
             for (const auto& itr : mapr) {
                 AstNode* const valuep = itr.second->valuep();
-                emitSetVarConstant(newPrefix + ".at(" + cvtToStr(itr.first) + ")",
+                emitSetVarConstant(newPrefix + ".atWrite(" + cvtToStr(itr.first) + ")",
                                    VN_AS(valuep, Const));
             }
         } else if (VN_IS(dtypep, WildcardArrayDType)) {
@@ -496,7 +496,7 @@ void EmitCFunc::emitVarReset(const string& prefix, AstVar* varp, bool constructi
             const auto& mapr = initarp->map();
             for (const auto& itr : mapr) {
                 AstNode* const valuep = itr.second->valuep();
-                emitSetVarConstant(newPrefix + ".at(" + cvtToStr(itr.first) + ")",
+                emitSetVarConstant(newPrefix + ".atWrite(" + cvtToStr(itr.first) + ")",
                                    VN_AS(valuep, Const));
             }
         } else if (AstUnpackArrayDType* const adtypep = VN_CAST(dtypep, UnpackArrayDType)) {
@@ -541,8 +541,8 @@ string EmitCFunc::emitVarResetRecurse(const AstVar* varp, bool constructing,
                                      depth + 1, suffix + ".atDefault()", nullptr);
     } else if (VN_IS(dtypep, CDType)) {
         return "";  // Constructor does it
-    } else if (VN_IS(dtypep, ClassRefDType)) {
-        return "";  // Constructor does it
+    } else if (const AstClassRefDType* const adtypep = VN_CAST(dtypep, ClassRefDType)) {
+        return adtypep->rawPointer() ? varNameProtected + suffix + " = nullptr;\n" : "";
     } else if (VN_IS(dtypep, IfaceRefDType)) {
         return varNameProtected + suffix + " = nullptr;\n";
     } else if (const AstDynArrayDType* const adtypep = VN_CAST(dtypep, DynArrayDType)) {

src/V3EmitCFunc.h

@@ -732,7 +732,8 @@ public:
     }
     void visit(AstAssocSel* nodep) override {
         iterateAndNextConstNull(nodep->fromp());
-        putnbs(nodep, ".at(");
+        const std::string atFunc = nodep->isLValue() ? ".atWrite(" : ".at(";
+        putnbs(nodep, atFunc);
         AstAssocArrayDType* const adtypep
             = VN_AS(nodep->fromp()->dtypep()->skipRefp(), AssocArrayDType);
         UASSERT_OBJ(adtypep, nodep, "Associative select on non-associative type");
@@ -741,7 +742,8 @@ public:
     }
     void visit(AstWildcardSel* nodep) override {
         iterateAndNextConstNull(nodep->fromp());
-        putnbs(nodep, ".at(");
+        const std::string atFunc = nodep->isLValue() ? ".atWrite(" : ".at(";
+        putnbs(nodep, atFunc);
         AstWildcardArrayDType* const adtypep
             = VN_AS(nodep->fromp()->dtypep()->skipRefp(), WildcardArrayDType);
         UASSERT_OBJ(adtypep, nodep, "Wildcard select on non-wildcard-associative type");