Support access to constructs inside type parameters (#3702)

This changeset brings support for accesses like:

	class Cls#(type TYPE1);
	    TYPE1::some_method();
	endclass

It is done by delaying dot resolution on type parameters until they get
resolved by V3Param, and doing a more thorough reference skip.

src/V3AstNodeDType.h

@@ -912,6 +912,7 @@ public:
         dtypep(nullptr);  // V3Width will resolve
     }
     ASTGEN_MEMBERS_AstParamTypeDType;
+    void dump(std::ostream& str = std::cout) const override;
     AstNodeDType* getChildDTypep() const override { return childDTypep(); }
     AstNodeDType* subDTypep() const override { return dtypep() ? dtypep() : childDTypep(); }
     AstBasicDType* basicp() const override VL_MT_SAFE { return subDTypep()->basicp(); }

src/V3AstNodes.cpp

@@ -1719,12 +1719,25 @@ void AstTimeImport::dump(std::ostream& str) const {
 void AstTypedef::dump(std::ostream& str) const {
     this->AstNode::dump(str);
     if (attrPublic()) str << " [PUBLIC]";
+    if (subDTypep()) {
+        str << " -> ";
+        subDTypep()->dump(str);
+    }
 }
 void AstNodeRange::dump(std::ostream& str) const { this->AstNode::dump(str); }
 void AstRange::dump(std::ostream& str) const {
     this->AstNodeRange::dump(str);
     if (littleEndian()) str << " [LITTLE]";
 }
+void AstParamTypeDType::dump(std::ostream& str) const {
+    this->AstNodeDType::dump(str);
+    if (subDTypep()) {
+        str << " -> ";
+        subDTypep()->dump(str);
+    } else {
+        str << " -> UNLINKED";
+    }
+}
 void AstRefDType::dump(std::ostream& str) const {
     this->AstNodeDType::dump(str);
     if (typedefp() || subDTypep()) {
@@ -2095,7 +2108,8 @@ void AstClassOrPackageRef::dump(std::ostream& str) const {
 }
 AstNodeModule* AstClassOrPackageRef::classOrPackagep() const {
     AstNode* foundp = m_classOrPackageNodep;
-    while (auto* const anodep = VN_CAST(foundp, Typedef)) foundp = anodep->subDTypep();
+    if (auto* const anodep = VN_CAST(foundp, Typedef)) foundp = anodep->subDTypep();
+    if (auto* const anodep = VN_CAST(foundp, NodeDType)) foundp = anodep->skipRefp();
     if (auto* const anodep = VN_CAST(foundp, ClassRefDType)) foundp = anodep->classp();
     return VN_CAST(foundp, NodeModule);
 }

src/V3LinkDot.cpp

@@ -2069,11 +2069,13 @@ private:
     }
 
     bool isParamedClassRef(const AstNode* nodep) {
+        // Is this a parametrized reference to a class, or a reference to class parameter
         if (const auto* classRefp = VN_CAST(nodep, ClassOrPackageRef)) {
             if (classRefp->paramsp()) return true;
             const auto* classp = classRefp->classOrPackageNodep();
             while (const auto* typedefp = VN_CAST(classp, Typedef)) classp = typedefp->subDTypep();
-            return VN_IS(classp, ClassRefDType) && VN_AS(classp, ClassRefDType)->paramsp();
+            return (VN_IS(classp, ClassRefDType) && VN_AS(classp, ClassRefDType)->paramsp())
+                   || VN_IS(classp, ParamTypeDType);
         }
         return false;
     }
@@ -2633,8 +2635,9 @@ private:
         // Class: Recurse inside or cleanup not founds
         // checkNoDot not appropriate, can be under a dot
         AstNode::user5ClearTree();
-        UASSERT_OBJ(m_statep->forPrimary() || nodep->classOrPackagep(), nodep,
-                    "ClassRef has unlinked class");
+        UASSERT_OBJ(m_statep->forPrimary() || VN_IS(nodep->classOrPackageNodep(), ParamTypeDType)
+                        || nodep->classOrPackagep(),
+                    nodep, "ClassRef has unlinked class");
         UASSERT_OBJ(m_statep->forPrimary() || !nodep->paramsp(), nodep,
                     "class reference parameter not removed by V3Param");
         VL_RESTORER(m_ds);

src/V3Param.cpp

@@ -936,11 +936,13 @@ class ParamVisitor final : public VNVisitor {
                     srcModp = modCellp->modp();
                 } else if (const auto* classRefp = VN_CAST(cellp, ClassOrPackageRef)) {
                     srcModp = classRefp->classOrPackagep();
+                    if (VN_IS(classRefp->classOrPackageNodep(), ParamTypeDType)) continue;
                 } else if (const auto* classRefp = VN_CAST(cellp, ClassRefDType)) {
                     srcModp = classRefp->classp();
                 } else {
                     cellp->v3fatalSrc("Expected module parametrization");
                 }
+                UASSERT_OBJ(srcModp, cellp, "Unlinked class ref");
 
                 // Update path
                 string someInstanceName(modp->someInstanceName());

test_regress/t/t_class_param_type.pl

@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2020 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
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;

test_regress/t/t_class_param_type.v

@@ -0,0 +1,32 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Arkadiusz Kozdra.
+// SPDX-License-Identifier: CC0-1.0
+
+// See also t_class_param.v
+
+class Parcls #(type T);
+   static function int get_p;
+     return T::get_p();
+   endfunction
+endclass
+
+class Cls;
+   static function int get_p;
+     return 20;
+   endfunction
+endclass
+
+typedef Cls cls_t;
+typedef cls_t cls2_t;
+
+module t (/*AUTOARG*/);
+
+   initial begin
+      if (Parcls#(cls2_t)::get_p() != 20) $stop;
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule