From 84ee833ea78d481a9a0db9150ee3a4038c7abc7d Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Sun, 2 Jan 2022 12:26:10 -0500
Subject: [PATCH] Ignore --x-initial unique inside classes.

---
 docs/guide/exe_verilator.rst | 7 ++++---
 src/V3Unknown.cpp            | 7 ++++++-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/docs/guide/exe_verilator.rst b/docs/guide/exe_verilator.rst
index b85a7036c..37741a603 100644
--- a/docs/guide/exe_verilator.rst
+++ b/docs/guide/exe_verilator.rst
@@ -1364,9 +1364,10 @@ Summary:
    .. note::
 
       This option applies only to values which are explicitly written as X
-      in the Verilog source code. Initial values of clocks are set to 0
-      unless `--x-initial-edge` is specified. Initial values of all other
-      state holding variables are controlled with `--x-initial`.
+      in modules (not classes) in the Verilog source code. Initial values
+      of clocks are set to 0 unless `--x-initial-edge` is
+      specified. Initial values of all other state holding variables are
+      controlled with `--x-initial`.
 
 .. option:: --x-initial 0
 
diff --git a/src/V3Unknown.cpp b/src/V3Unknown.cpp
index b5daaf8a5..e1db3adc5 100644
--- a/src/V3Unknown.cpp
+++ b/src/V3Unknown.cpp
@@ -57,6 +57,7 @@ private:
     AstAssignW* m_assignwp = nullptr;  // Current assignment
     AstAssignDly* m_assigndlyp = nullptr;  // Current assignment
     bool m_constXCvt = false;  // Convert X's
+    bool m_allowXUnique = true;  // Allow unique assignments
     VDouble0 m_statUnkVars;  // Statistic tracking
     V3UniqueNames m_lvboundNames;  // For generating unique temporary variable names
     V3UniqueNames m_xrandNames;  // For generating unique temporary variable names
@@ -141,9 +142,12 @@ private:
         UINFO(4, " MOD   " << nodep << endl);
         VL_RESTORER(m_modp);
         VL_RESTORER(m_constXCvt);
+        VL_RESTORER(m_allowXUnique);
         {
             m_modp = nodep;
             m_constXCvt = true;
+            // Class X randomization causes Vxrand in strange places, so disable
+            if (VN_IS(nodep, Class)) m_allowXUnique = false;
             m_lvboundNames.reset();
             m_xrandNames.reset();
             iterateChildren(nodep);
@@ -310,7 +314,7 @@ private:
             numb1.opBitsOne(nodep->num());
             V3Number numbx(nodep, nodep->width());
             numbx.opBitsXZ(nodep->num());
-            if (v3Global.opt.xAssign() != "unique") {
+            if (!m_allowXUnique || v3Global.opt.xAssign() != "unique") {
                 // All X bits just become 0; fastest simulation, but not nice
                 V3Number numnew(nodep, numb1.width());
                 if (v3Global.opt.xAssign() == "1") {
@@ -329,6 +333,7 @@ private:
                 AstVar* const newvarp
                     = new AstVar(nodep->fileline(), AstVarType::XTEMP, m_xrandNames.get(nodep),
                                  VFlagLogicPacked(), nodep->width());
+                newvarp->lifetime(VLifetime::STATIC);
                 ++m_statUnkVars;
                 VNRelinker replaceHandle;
                 nodep->unlinkFrBack(&replaceHandle);