Add error on randc inside dist

src/V3LinkResolve.cpp

@@ -47,6 +47,8 @@ class LinkResolveVisitor final : public VNVisitor {
     // Below state needs to be preserved between each module call.
     AstNodeModule* m_modp = nullptr;  // Current module
     AstClass* m_classp = nullptr;  // Class we're inside
+    string m_randcIllegalWhy;  // Why randc illegal
+    AstNode* m_randcIllegalp = nullptr;  // Node causing randc illegal
     AstNodeFTask* m_ftaskp = nullptr;  // Function or task we're inside
     AstNodeCoverOrAssert* m_assertp = nullptr;  // Current assertion
     int m_senitemCvtNum = 0;  // Temporary signal counter
@@ -82,6 +84,30 @@ class LinkResolveVisitor final : public VNVisitor {
         }
         iterateChildren(nodep);
     }
+    void visit(AstConstraintBefore* nodep) override {
+        VL_RESTORER(m_randcIllegalWhy);
+        VL_RESTORER(m_randcIllegalp);
+        m_randcIllegalWhy = "'solve before' (IEEE 1800-2023 18.5.9)";
+        m_randcIllegalp = nodep;
+        iterateChildrenConst(nodep);
+    }
+    void visit(AstDist* nodep) override {
+        VL_RESTORER(m_randcIllegalWhy);
+        VL_RESTORER(m_randcIllegalp);
+        m_randcIllegalWhy = "'constraint dist' (IEEE 1800-2023 18.5.3)";
+        m_randcIllegalp = nodep;
+        iterateChildrenConst(nodep);
+    }
+    void visit(AstConstraintExpr* nodep) override {
+        VL_RESTORER(m_randcIllegalWhy);
+        VL_RESTORER(m_randcIllegalp);
+        if (nodep->isSoft()) {
+            m_randcIllegalWhy = "'constraint soft' (IEEE 1800-2023 18.5.13.1)";
+            m_randcIllegalp = nodep;
+        }
+        iterateChildrenConst(nodep);
+    }
+
     void visit(AstInitialAutomatic* nodep) override {
         iterateChildren(nodep);
         // Initial assignments under function/tasks can just be simple
@@ -110,14 +136,25 @@ class LinkResolveVisitor final : public VNVisitor {
     }
 
     void visit(AstNodeVarRef* nodep) override {
+        if (nodep->varp()) {  // Else due to dead code, might not have var pointer
             // VarRef: Resolve its reference
-        if (nodep->varp()) nodep->varp()->usedParam(true);
+            nodep->varp()->usedParam(true);
             // TODO should look for where genvar is valid, but for now catch
             // just gross errors of using genvar outside any generate
-        if (nodep->varp() && nodep->varp()->isGenVar() && !m_underGenFor) {
-            nodep->v3error("Genvar " << nodep->prettyNameQ()
+            if (nodep->varp()->isGenVar() && !m_underGenFor) {
+                nodep->v3error("Genvar "
+                               << nodep->prettyNameQ()
                                << " used outside generate for loop (IEEE 1800-2023 27.4)");
             }
+            if (nodep->varp()->isRandC() && m_randcIllegalp) {
+                nodep->v3error("Randc variables not allowed in "
+                               << m_randcIllegalWhy << '\n'
+                               << nodep->warnContextPrimary() << '\n'
+                               << m_randcIllegalp->warnOther()
+                               << "... Location of restricting expression\n"
+                               << m_randcIllegalp->warnContextSecondary());
+            }
+        }
         iterateChildren(nodep);
     }
 

src/V3Randomize.cpp

@@ -131,8 +131,6 @@ class RandomizeMarkVisitor final : public VNVisitor {
 
     BaseToDerivedMap m_baseToDerivedMap;  // Mapping from base classes to classes that extend them
     AstClass* m_classp = nullptr;  // Current class
-    AstConstraintBefore* m_constraintBeforep = nullptr;  // Current before constraint
-    AstConstraintExpr* m_constraintExprp = nullptr;  // Current constraint expression
     AstNode* m_constraintExprGenp = nullptr;  // Current constraint or constraint if expression
     AstNodeModule* m_modp;  // Current module
     AstNodeStmt* m_stmtp = nullptr;  // Current statement
@@ -403,14 +401,7 @@ class RandomizeMarkVisitor final : public VNVisitor {
             }
         }
     }
-    void visit(AstConstraintBefore* nodep) override {
-        VL_RESTORER(m_constraintBeforep);
-        m_constraintBeforep = nodep;
-        iterateChildrenConst(nodep);
-    }
     void visit(AstConstraintExpr* nodep) override {
-        VL_RESTORER(m_constraintExprp);
-        m_constraintExprp = nodep;
         VL_RESTORER(m_constraintExprGenp);
         m_constraintExprGenp = nodep;
         iterateChildrenConst(nodep);
@@ -425,15 +416,6 @@ class RandomizeMarkVisitor final : public VNVisitor {
         iterateAndNextConstNull(nodep->elsesp());
     }
     void visit(AstNodeVarRef* nodep) override {
-        if (nodep->varp()->isRandC()) {
-            if (m_constraintExprp && m_constraintExprp->isSoft()) {
-                nodep->v3error(
-                    "Randc variables not allowed in 'constraint soft' (IEEE 1800-2023 18.5.13.1)");
-            } else if (m_constraintBeforep) {
-                nodep->v3error(
-                    "Randc variables not allowed in 'solve before' (IEEE 1800-2023 18.5.9)");
-            }
-        }
         if (!m_constraintExprGenp) return;
 
         if (nodep->varp()->lifetime().isStatic()) m_staticRefs.emplace(nodep);

test_regress/t/t_constraint_before_randc_bad.out

@@ -0,0 +1,7 @@
+%Error: t/t_constraint_before_randc_bad.v:11:45: Randc variables not allowed in 'solve before' (IEEE 1800-2023 18.5.9)
+   11 |     constraint raint2_bad { solve b1 before b2; }   
+      |                                             ^~
+        t/t_constraint_before_randc_bad.v:11:29: ... Location of restricting expression
+   11 |     constraint raint2_bad { solve b1 before b2; }   
+      |                             ^~~~~
+%Error: Exiting due to

test_regress/t/t_constraint_dist_randc_bad.out

@@ -0,0 +1,7 @@
+%Error: t/t_constraint_dist_randc_bad.v:10:23: Randc variables not allowed in 'constraint dist' (IEEE 1800-2023 18.5.3)
+   10 |    constraint c_bad { rc dist {3 := 0, 10 := 5}; }   
+      |                       ^~
+        t/t_constraint_dist_randc_bad.v:10:26: ... Location of restricting expression
+   10 |    constraint c_bad { rc dist {3 := 0, 10 := 5}; }   
+      |                          ^~~~
+%Error: Exiting due to

test_regress/t/t_constraint_dist_randc_bad.v

@@ -0,0 +1,14 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+class Cls1;
+   randc int rc;
+
+   constraint c_bad { rc dist {3 := 0, 10 := 5}; }  // Bad, no dist on randc
+endclass
+
+module t (/*AUTOARG*/);
+endmodule

test_regress/t/t_constraint_soft_randc_bad.out

@@ -0,0 +1,7 @@
+%Error: t/t_constraint_soft_randc_bad.v:10:28: Randc variables not allowed in 'constraint soft' (IEEE 1800-2023 18.5.13.1)
+   10 |    constraint c_bad { soft rc > 4; }   
+      |                            ^~
+        t/t_constraint_soft_randc_bad.v:10:23: ... Location of restricting expression
+   10 |    constraint c_bad { soft rc > 4; }   
+      |                       ^~~~
+%Error: Exiting due to

test_regress/t/t_constraint_soft_randc_bad.py

@@ -0,0 +1,16 @@
+#!/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('linter')
+
+test.lint(fails=test.vlt_all, expect_filename=test.golden_filename)
+
+test.passes()

test_regress/t/t_randomize_before_randc_bad.out

@@ -1,5 +0,0 @@
-%Error: t/t_randomize_before_randc_bad.v:11:45: Randc variables not allowed in 'solve before' (IEEE 1800-2023 18.5.9)
-                                              : ... note: In instance 't'
-   11 |     constraint raint2_bad { solve b1 before b2; }   
-      |                                             ^~
-%Error: Exiting due to

test_regress/t/t_randomize_soft_randc_bad.out

@@ -1,5 +0,0 @@
-%Error: t/t_randomize_soft_randc_bad.v:10:28: Randc variables not allowed in 'constraint soft' (IEEE 1800-2023 18.5.13.1)
-                                            : ... note: In instance 't'
-   10 |    constraint c_bad { soft rc > 4; }   
-      |                            ^~
-%Error: Exiting due to