Support class type params without defaults (#3693)

src/V3LinkDot.cpp

@@ -161,6 +161,7 @@ private:
     bool m_forPrimary;  // First link
     bool m_forPrearray;  // Compress cell__[array] refs
     bool m_forScopeCreation;  // Remove VarXRefs for V3Scope
+    bool m_removeVoidParamedClasses;  // Remove classes with void params
 
 public:
     // METHODS
@@ -207,6 +208,7 @@ public:
         m_forPrimary = (step == LDS_PRIMARY);
         m_forPrearray = (step == LDS_PARAMED || step == LDS_PRIMARY);
         m_forScopeCreation = (step == LDS_SCOPED);
+        m_removeVoidParamedClasses = (step == LDS_PARAMED);
         s_errorThisp = this;
         V3Error::errorExitCb(preErrorDumpHandler);  // If get error, dump self
     }
@@ -220,6 +222,7 @@ public:
     bool forPrimary() const { return m_forPrimary; }
     bool forPrearray() const { return m_forPrearray; }
     bool forScopeCreation() const { return m_forScopeCreation; }
+    bool removeVoidParamedClasses() const { return m_removeVoidParamedClasses; }
 
     // METHODS
     static string nodeTextType(AstNode* nodep) {
@@ -902,6 +905,18 @@ class LinkDotFindVisitor final : public VNVisitor {
     void visit(AstClass* nodep) override {
         UASSERT_OBJ(m_curSymp, nodep, "Class not under module/package/$unit");
         UINFO(8, "   " << nodep << endl);
+        // Remove classes that have void params, as they were only used for the parametrization
+        // step and will not be instantiated
+        if (m_statep->removeVoidParamedClasses()) {
+            for (auto* stmtp = nodep->stmtsp(); stmtp; stmtp = stmtp->nextp()) {
+                if (auto* dtypep = VN_CAST(stmtp, ParamTypeDType)) {
+                    if (VN_IS(dtypep->subDTypep(), VoidDType)) {
+                        VL_DO_DANGLING(nodep->unlinkFrBack()->deleteTree(), nodep);
+                        return;
+                    }
+                }
+            }
+        }
         VL_RESTORER(m_scope);
         VL_RESTORER(m_classOrPackagep);
         VL_RESTORER(m_modSymp);

src/V3LinkParse.cpp

@@ -209,18 +209,16 @@ private:
         }
         if (VN_IS(nodep->subDTypep(), ParseTypeDType)) {
             // It's a parameter type. Use a different node type for this.
-            AstNodeDType* const dtypep = VN_CAST(nodep->valuep(), NodeDType);
-            if (!dtypep) {
-                nodep->v3error(
-                    "Parameter type's initial value isn't a type: " << nodep->prettyNameQ());
-                nodep->unlinkFrBack();
-            } else {
+            AstNodeDType* dtypep = VN_CAST(nodep->valuep(), NodeDType);
+            if (dtypep) {
                 dtypep->unlinkFrBack();
-                AstNode* const newp = new AstParamTypeDType(
-                    nodep->fileline(), nodep->varType(), nodep->name(), VFlagChildDType(), dtypep);
-                nodep->replaceWith(newp);
-                VL_DO_DANGLING(nodep->deleteTree(), nodep);
+            } else {
+                dtypep = new AstVoidDType{nodep->fileline()};
             }
+            AstNode* const newp = new AstParamTypeDType{nodep->fileline(), nodep->varType(),
+                                                        nodep->name(), VFlagChildDType{}, dtypep};
+            nodep->replaceWith(newp);
+            VL_DO_DANGLING(nodep->deleteTree(), nodep);
             return;
         }
 

src/V3Param.cpp

@@ -801,6 +801,15 @@ class ParamProcessor final {
             srcModpr = modInfop->m_modp;
         }
 
+        for (auto* stmtp = srcModpr->stmtsp(); stmtp; stmtp = stmtp->nextp()) {
+            if (auto* dtypep = VN_CAST(stmtp, ParamTypeDType)) {
+                if (VN_IS(dtypep->subDTypep(), VoidDType)) {
+                    nodep->v3error("Missing type parameter: " << dtypep->prettyNameQ());
+                    VL_DO_DANGLING(nodep->unlinkFrBack()->deleteTree(), nodep);
+                }
+            }
+        }
+
         // Delete the parameters from the cell; they're not relevant any longer.
         if (paramsp) paramsp->unlinkFrBackWithNext()->deleteTree();
         return any_overrides;
@@ -822,8 +831,11 @@ class ParamProcessor final {
     }
 
     void classRefDeparam(AstClassRefDType* nodep, AstNodeModule*& srcModpr) {
-        if (nodeDeparamCommon(nodep, srcModpr, nodep->paramsp(), nullptr, false))
-            nodep->classp(VN_AS(srcModpr, Class));
+        if (nodeDeparamCommon(nodep, srcModpr, nodep->paramsp(), nullptr, false)) {
+            AstClass* const classp = VN_AS(srcModpr, Class);
+            nodep->classp(classp);
+            nodep->classOrPackagep(classp);
+        }
     }
 
 public:

src/verilog.y

@@ -2882,7 +2882,9 @@ list_of_param_assignments<varp>:        // ==IEEE: list_of_param_assignments
 
 type_assignment<varp>:          // ==IEEE: type_assignment
         //                      // note exptOrDataType being a data_type is only for yPARAMETER yTYPE
-                idAny/*new-parameter*/ sigAttrListE '=' data_type
+                idAny/*new-parameter*/ sigAttrListE
+                        { $$ = VARDONEA($<fl>1, *$1, nullptr, $2); }
+        |       idAny/*new-parameter*/ sigAttrListE '=' data_type
                         { $$ = VARDONEA($<fl>1, *$1, nullptr, $2); $$->valuep($4); }
         ;
 

test_regress/t/t_class_param_bad.out

@@ -1,9 +0,0 @@
-%Error-PINNOTFOUND: t/t_class_param_bad.v:12:11: Parameter pin not found: 'PARAMBAD'
-                                               : ... Suggested alternative: 'PARAMB'
-   12 |    Cls #(.PARAMBAD(1)) c;   
-      |           ^~~~~~~~
-                    ... For error description see https://verilator.org/warn/PINNOTFOUND?v=latest
-%Error-PINNOTFOUND: t/t_class_param_bad.v:13:14: Parameter pin not found: '__paramNumber2'
-   13 |    Cls #(13, 1) cd;   
-      |              ^
-%Error: Exiting due to

test_regress/t/t_class_param_bad1.out

@@ -0,0 +1,9 @@
+%Error-PINNOTFOUND: t/t_class_param_bad1.v:12:11: Parameter pin not found: 'PARAMBAD'
+                                                : ... Suggested alternative: 'PARAMB'
+   12 |    Cls #(.PARAMBAD(1)) c;   
+      |           ^~~~~~~~
+                    ... For error description see https://verilator.org/warn/PINNOTFOUND?v=latest
+%Error-PINNOTFOUND: t/t_class_param_bad1.v:13:14: Parameter pin not found: '__paramNumber2'
+   13 |    Cls #(13, 1) cd;   
+      |              ^
+%Error: Exiting due to

test_regress/t/t_class_param_bad2.out

@@ -0,0 +1,5 @@
+%Error: t/t_class_param_bad2.v:12:4: Missing type parameter: 'PARAMB'
+                                   : ... In instance t
+   12 |    Cls c;   
+      |    ^~~
+%Error: Exiting due to

test_regress/t/t_class_param_bad2.pl

@@ -0,0 +1,19 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2022 by Antmicro Ltd. 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
+
+scenarios(linter => 1);
+
+lint(
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;

test_regress/t/t_class_param_bad2.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, 2022 by Antmicro Ltd.
+// SPDX-License-Identifier: CC0-1.0
+
+class Cls #(type PARAMB);
+endclass
+
+module t (/*AUTOARG*/);
+
+   Cls c;  // Missing type param
+
+endmodule

test_regress/t/t_class_vparam.v

@@ -14,7 +14,7 @@ virtual class vclass #(type CTYPE_t = arg_class_t, int I = 0);
    pure virtual function void funcname(paramed_class_t #(CTYPE_t) v);
 endclass
 
-class paramed_class_t #(type TYPE = int, int I = 0);
+class paramed_class_t #(type TYPE, int I = 0);
    TYPE memb;
 endclass