Support virtual class

Changes

@@ -9,7 +9,7 @@ The contributors that suggested a given feature are shown in []. Thanks!
 
 **    Support hierarchical Verilation (#2206). [Yutetsu TAKATSUKASA]
 
-****  Support class extern.
+****  Support (with limitations) class extern, class extends, virtual class.
 
 ****  Support $urandom, $urandom_range without stability.
 

src/V3Task.cpp

@@ -1036,7 +1036,7 @@ private:
         // Unless public, v3Descope will not uniquify function names even if duplicate per-scope,
         // so make it unique now.
         string suffix;  // So, make them unique
-        if (!nodep->taskPublic()) suffix = "_" + m_scopep->nameDotless();
+        if (!nodep->taskPublic() && !nodep->classMethod()) suffix = "_" + m_scopep->nameDotless();
         string name = ((nodep->name() == "new") ? "new" : prefix + nodep->name() + suffix);
         AstCFunc* cfuncp = new AstCFunc(
             nodep->fileline(), name, m_scopep,
@@ -1049,6 +1049,7 @@ private:
         cfuncp->dpiExport(nodep->dpiExport());
         cfuncp->dpiImportWrapper(nodep->dpiImport());
         cfuncp->isStatic(!(nodep->dpiImport() || nodep->taskPublic() || nodep->classMethod()));
+        cfuncp->isVirtual(nodep->isVirtual());
         cfuncp->pure(nodep->pure());
         if (nodep->name() == "new") {
             cfuncp->isConstructor(true);

src/V3Width.cpp

@@ -2028,7 +2028,6 @@ private:
     virtual void visit(AstClass* nodep) override {
         if (nodep->didWidthAndSet()) return;
         userIterateChildren(nodep, nullptr);  // First size all members
-        if (nodep->isVirtual()) nodep->v3warn(E_UNSUPPORTED, "Unsupported: virtual class");
         nodep->repairCache();
     }
     virtual void visit(AstClassRefDType* nodep) override {
@@ -2739,7 +2738,10 @@ private:
             // Either made explicitly or V3LinkDot made implicitly
             classp->v3fatalSrc("Can't find class's new");
         }
-
+        if (classp->isVirtual()) {
+            nodep->v3error(
+                "Illegal to call 'new' using an abstract virtual class (IEEE 1800-2017 8.21)");
+        }
         userIterate(nodep->taskp(), nullptr);
         userIterateChildren(nodep, nullptr);
         processFTaskRefArgs(nodep);
@@ -3771,9 +3773,6 @@ private:
             nodep->didWidth(true);
             return;
         }
-        if (nodep->isVirtual() || nodep->pureVirtual()) {
-            nodep->v3warn(E_UNSUPPORTED, "Unsupported: 'virtual' class method");
-        }
         // Function hasn't been widthed, so make it so.
         // Would use user1 etc, but V3Width called from too many places to spend a user
         nodep->doingWidth(true);

test_regress/t/t_class_virtual.out

@@ -1,7 +0,0 @@
-%Error-UNSUPPORTED: t/t_class_virtual.v:8:25: Unsupported: 'virtual' class method
-    8 |    virtual function int hello;
-      |                         ^~~~~
-%Error-UNSUPPORTED: t/t_class_virtual.v:7:9: Unsupported: virtual class
-    7 | virtual class VBase;
-      |         ^~~~~
-%Error: Exiting due to

test_regress/t/t_class_virtual.pl

@@ -8,11 +8,13 @@ if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); di
 # Version 2.0.
 # SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
 
-scenarios(vlt => 1);
+scenarios(simulator => 1);
 
-lint(
-    fails => 1,
-    expect_filename => $Self->{golden_filename},
+compile(
+    );
+
+execute(
+    check_finished => 1,
     );
 
 ok(1);

test_regress/t/t_class_virtual.v

@@ -10,14 +10,13 @@ virtual class VBase;
    endfunction
 endclass
 
-`ifndef VERILATOR
-virtual class VA extends VBase;
+class VA extends VBase;
    virtual function int hello;
       return 2;
    endfunction
 endclass
 
-virtual class VB extends VBase;
+class VB extends VBase;
    virtual function int hello;
       return 3;
    endfunction
@@ -28,6 +27,10 @@ module t;
       VA va = new;
       VB vb = new;
       VBase b;
+
+      if (va.hello() != 2) $stop;
+      if (vb.hello() != 3) $stop;
+
       b = va;
       if (b.hello() != 2) $stop;
       b = vb;
@@ -36,4 +39,3 @@ module t;
       $finish;
    end
 endmodule
-`endif

test_regress/t/t_class_virtual_bad.out

@@ -0,0 +1,5 @@
+%Error: t/t_class_virtual_bad.v:12:17: Illegal to call 'new' using an abstract virtual class (IEEE 1800-2017 8.21)
+                                     : ... In instance t
+   12 |       VBase b = new;   
+      |                 ^~~
+%Error: Exiting due to

test_regress/t/t_class_virtual_bad.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 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(vlt => 1);
+
+lint(
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;

test_regress/t/t_class_virtual_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, 2019 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+virtual class VBase;
+endclass
+
+module t;
+   initial begin
+      VBase b = new;  // Error
+   end
+endmodule

test_regress/t/t_class_virtual_pure.pl

@@ -8,11 +8,13 @@ if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); di
 # Version 2.0.
 # SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
 
-scenarios(vlt => 1);
+scenarios(simulator => 1);
 
-lint(
-    fails => 1,
-    expect_filename => $Self->{golden_filename},
+compile(
+    );
+
+execute(
+    check_finished => 1,
     );
 
 ok(1);

test_regress/t/t_class_virtual_pure.v

@@ -4,6 +4,21 @@
 // any use, without warranty, 2019 by Wilson Snyder.
 // SPDX-License-Identifier: CC0-1.0
 
-virtual class VC;
-   pure virtual task hello();
+virtual class VBase;
+   pure virtual function int hello();
 endclass
+
+class VA extends VBase;
+   virtual function int hello;
+      return 2;
+   endfunction
+endclass
+
+module t;
+   initial begin
+      VA va = new;
+      if (va.hello() != 2) $stop;
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule