Fix complex user type problem with --x-assign (#5543)

src/V3LinkDot.cpp

@@ -1333,9 +1333,10 @@ class LinkDotFindVisitor final : public VNVisitor {
                     } else {
                         findvarp->combineType(nodep);
                         findvarp->fileline()->modifyStateInherit(nodep->fileline());
-                        if (nodep->getChildDTypep()->numeric().isSigned()
-                            && !findvarp->getChildDTypep()->numeric().isSigned()) {
-                            findvarp->getChildDTypep()->numeric(VSigning{true});
+                        UASSERT_OBJ(nodep->subDTypep(), nodep, "Var has no type");
+                        if (nodep->subDTypep()->numeric().isSigned()
+                            && !findvarp->subDTypep()->numeric().isSigned()) {
+                            findvarp->subDTypep()->numeric(VSigning{true});
                         }
                         AstBasicDType* const bdtypep
                             = VN_CAST(findvarp->childDTypep(), BasicDType);

src/V3Unknown.cpp

@@ -48,6 +48,7 @@ class UnknownVisitor final : public VNVisitor {
     //  AstNode::user2p()       -> AstIf* Inserted if assignment for conditional
     const VNUser1InUse m_inuser1;
     const VNUser2InUse m_inuser2;
+    static const std::string m_xrandPrefix;
 
     // STATE
     AstNodeModule* m_modp = nullptr;  // Current module
@@ -58,7 +59,7 @@ class UnknownVisitor final : public VNVisitor {
     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
+    std::unique_ptr<V3UniqueNames> m_xrandNames;  // For generating unique temporary variable names
 
     // METHODS
 
@@ -141,14 +142,16 @@ class UnknownVisitor final : public VNVisitor {
         VL_RESTORER(m_modp);
         VL_RESTORER(m_constXCvt);
         VL_RESTORER(m_allowXUnique);
+        auto xrandNames = std::make_unique<V3UniqueNames>(m_xrandPrefix);
         {
             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();
+            xrandNames.swap(m_xrandNames);
             iterateChildren(nodep);
+            xrandNames.swap(m_xrandNames);
         }
     }
     void visit(AstAssignDly* nodep) override {
@@ -345,7 +348,7 @@ class UnknownVisitor final : public VNVisitor {
                 // We use the special XTEMP type so it doesn't break pure functions
                 UASSERT_OBJ(m_modp, nodep, "X number not under module");
                 AstVar* const newvarp
-                    = new AstVar{nodep->fileline(), VVarType::XTEMP, m_xrandNames.get(nodep),
+                    = new AstVar{nodep->fileline(), VVarType::XTEMP, m_xrandNames->get(nodep),
                                  VFlagLogicPacked{}, nodep->width()};
                 newvarp->lifetime(VLifetime::STATIC);
                 ++m_statUnkVars;
@@ -517,7 +520,7 @@ public:
     // CONSTRUCTORS
     explicit UnknownVisitor(AstNetlist* nodep)
         : m_lvboundNames{"__Vlvbound"}
-        , m_xrandNames{"__Vxrand"} {
+        , m_xrandNames{std::make_unique<V3UniqueNames>(m_xrandPrefix)} {
         iterate(nodep);
     }
     ~UnknownVisitor() override {  //
@@ -525,6 +528,8 @@ public:
     }
 };
 
+const std::string UnknownVisitor::m_xrandPrefix = "__Vxrand";
+
 //######################################################################
 // Unknown class functions
 

test_regress/t/t_user_type_xassign.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2024 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.compile()
+
+test.execute()
+
+test.passes()

test_regress/t/t_user_type_xassign.v

@@ -0,0 +1,43 @@
+// DESCRIPTION: Verilator: Demonstrate complex user typea problem with --x-assign
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2024 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t (/*AUTOARG*/
+   // Inputs
+   clk
+   );
+
+   input clk;
+
+   typedef logic [31:0] int_t;
+   typedef int_t [6:0] bar_t;
+   bar_t the_bar;
+
+   logic [31:0] thing_one;
+   always_comb begin
+       for (int sel = 0; sel < 1; sel++)
+           thing_one = the_bar[sel];
+   end
+
+   virtual class SomeClass;
+       static function logic compare(int a, int b);
+           return a > b;
+       endfunction
+   endclass
+
+   logic [31:0] thing_two;
+   always_comb begin
+       for (int sel_a = 0; sel_a < 1; sel_a++)
+           thing_two = the_bar[sel_a];
+   end
+
+   // finish report
+   always @ (posedge clk) begin
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+
+
+endmodule