From 7e3cd8af655c6d9425c4500afcd48e74736c6bc6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Chmiel?= <bchmiel@antmicro.com>
Date: Thu, 8 Jan 2026 21:10:19 +0100
Subject: [PATCH] Fix tracing signals with escaped dots in names (#6897)

---
 src/V3TraceDecl.cpp                  | 17 +++++++++-------
 test_regress/t/t_var_escape_noinl.py | 30 ++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 7 deletions(-)
 create mode 100755 test_regress/t/t_var_escape_noinl.py

diff --git a/src/V3TraceDecl.cpp b/src/V3TraceDecl.cpp
index 9a8ad49b2..8cc34b198 100644
--- a/src/V3TraceDecl.cpp
+++ b/src/V3TraceDecl.cpp
@@ -262,15 +262,17 @@ class TraceDeclVisitor final : public VNVisitor {
         // Find the scope for the path. As we are working based on cell names,
         // it is possible there is no corresponding scope (e.g.: for an empty
         // module).
-        const auto it = m_pathToScopep.find(path);
+        const auto it = m_pathToScopep.find(AstNode::prettyName(path));
         if (it != m_pathToScopep.end()) {
             const AstScope* const scopep = it->second;
             FileLine* const flp = placeholderp->fileline();
 
             // Pick up the last path element. The prefixes have already been pushed
-            // when building the initialization functions
-            const size_t pos = path.rfind('.');
-            const std::string name = path.substr(pos == string::npos ? 0 : pos + 1);
+            // when building the initialization.
+            // We still need to find __DOT__ as cell names may have such.
+            const std::string dot = "__DOT__";
+            const size_t pos = path.rfind(dot);
+            const std::string name = path.substr(pos == string::npos ? 0 : pos + dot.size());
 
             // Compute the type of the scope being fixed up
             const AstCell* const cellp = scopep->aboveCellp();
@@ -280,7 +282,8 @@ class TraceDeclVisitor final : public VNVisitor {
                         : VTracePrefixType::SCOPE_MODULE;
 
             // Push the scope prefix
-            AstNodeStmt* const pushp = new AstTracePushPrefix{flp, name, scopeType};
+            AstNodeStmt* const pushp
+                = new AstTracePushPrefix{flp, AstNode::prettyName(name), scopeType};
 
             // Call the initialization functions for the scope
             for (AstCFunc* const subFuncp : m_scopeInitFuncps.at(scopep)) {
@@ -308,7 +311,7 @@ class TraceDeclVisitor final : public VNVisitor {
             const AstScope* const parentp = std::get<0>(item);
             const AstCell* const cellp = std::get<1>(item);
             AstNodeStmt* const placeholderp = std::get<2>(item);
-            const std::string path = AstNode::prettyName(parentp->name() + "." + cellp->name());
+            const std::string path = parentp->name() + "__DOT__" + cellp->name();
             fixupPlaceholder(path, placeholderp);
         }
 
@@ -316,7 +319,7 @@ class TraceDeclVisitor final : public VNVisitor {
         for (const auto& item : m_ifaceRefInitPlaceholders) {
             const AstVarScope* const vscp = std::get<0>(item);
             AstNodeStmt* const placeholderp = std::get<1>(item);
-            const std::string path = vscp->prettyName();
+            const std::string path = vscp->scopep()->name() + "__DOT__" + vscp->varp()->name();
             fixupPlaceholder(path, placeholderp);
         }
     }
diff --git a/test_regress/t/t_var_escape_noinl.py b/test_regress/t/t_var_escape_noinl.py
new file mode 100755
index 000000000..dc717ba7e
--- /dev/null
+++ b/test_regress/t/t_var_escape_noinl.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2026 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+test.top_filename = "t/t_var_escape.v"
+test.golden_filename = "t/t_var_escape.out"
+
+test.compile(
+    # Access is so we can dump waves
+    v_flags2=['-trace' if test.vlt_all else ' +access+rwc', '-fno-inline'])
+
+test.execute()
+
+if test.vlt_all:
+    test.file_grep(test.trace_filename, r'\$enddefinitions')
+    sigre = re.escape("bra[ket]slash/dash-colon:9")
+    test.file_grep(test.trace_filename, sigre)
+    test.file_grep(test.trace_filename, r' other\.cyc ')
+    test.file_grep(test.trace_filename, r' module mod\.with_dot ')
+    test.vcd_identical(test.trace_filename, test.golden_filename)
+
+test.passes()