Support parsing anonymous primitive instantiations (#4809)

src/V3LinkParse.cpp

@@ -56,6 +56,7 @@ class LinkParseVisitor final : public VNVisitor {
     AstNodeDType* m_dtypep = nullptr;  // Current data type
     AstNodeExpr* m_defaultInSkewp = nullptr;  // Current default input skew
     AstNodeExpr* m_defaultOutSkewp = nullptr;  // Current default output skew
+    int m_anonUdpId = 0;  // Counter for anonymous UDP instances
     int m_genblkAbove = 0;  // Begin block number of if/case/for above
     int m_genblkNum = 0;  // Begin block number, 0=none seen
     int m_beginDepth = 0;  // How many begin blocks above current node within current AstNodeModule
@@ -621,6 +622,7 @@ class LinkParseVisitor final : public VNVisitor {
         V3Config::applyModule(nodep);
 
         VL_RESTORER(m_modp);
+        VL_RESTORER(m_anonUdpId);
         VL_RESTORER(m_genblkAbove);
         VL_RESTORER(m_genblkNum);
         VL_RESTORER(m_beginDepth);
@@ -631,6 +633,7 @@ class LinkParseVisitor final : public VNVisitor {
             // Classes inherit from upper package
             if (m_modp && nodep->timeunit().isNone()) nodep->timeunit(m_modp->timeunit());
             m_modp = nodep;
+            m_anonUdpId = 0;
             m_genblkAbove = 0;
             m_genblkNum = 0;
             m_beginDepth = 0;
@@ -700,6 +703,19 @@ class LinkParseVisitor final : public VNVisitor {
             iterateChildren(nodep);
         }
     }
+    void visit(AstCell* nodep) override {
+        if (nodep->origName().empty()) {
+            if (!VN_IS(nodep->modp(), Primitive)) {  // Module/Program/Iface
+                nodep->modNameFileline()->v3error("Instance of " << nodep->modp()->verilogKwd()
+                                                                 << " must be named");
+            }
+            // UDPs can have empty instance names. Assigning unique names for them to prevent any
+            // conflicts
+            const string newName = "$unnamedudp" + cvtToStr(++m_anonUdpId);
+            nodep->name(newName);
+            nodep->origName(newName);
+        }
+    }
     void visit(AstGenCase* nodep) override {
         ++m_genblkNum;
         cleanFileline(nodep);

src/verilog.y

@@ -3203,10 +3203,8 @@ instnameParen<nodep>:
                         { $$ = GRAMMARP->createCellOrIfaceRef($<fl>1, *$1, $4, $2, true); }
         |       id instRangeListE
                         { $$ = GRAMMARP->createCellOrIfaceRef($<fl>1, *$1, nullptr, $2, false); }
-        //UNSUP instRangeListE '(' cellpinListE ')'      { UNSUP } // UDP
-        //                      // Adding above and switching to the Verilog-Perl syntax
-        //                      // causes a shift conflict due to use of idClassSel inside exprScope.
-        //                      // It also breaks allowing "id foo;" instantiation syntax.
+        |       '(' cellpinListE ')'  // When UDP has empty name, unpacked dimensions must not be used
+                        { $$ = GRAMMARP->createCellOrIfaceRef($<fl>1, "", $2, nullptr, true); }
         ;
 
 instRangeListE<nodeRangep>:

test_regress/t/t_inst_noname_bad.out

@@ -0,0 +1,7 @@
+%Error: t/t_inst_noname_bad.v:8:5: Instance of module must be named
+    8 |     m ();
+      |     ^
+%Error: t/t_inst_noname_bad.v:9:5: Instance of module must be named
+    9 |     m ();
+      |     ^
+%Error: Exiting due to

test_regress/t/t_inst_noname_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 2003 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(linter => 1);
+
+lint(
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;

test_regress/t/t_inst_noname_bad.v

@@ -0,0 +1,13 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2023 by Anthony Donlon.
+// SPDX-License-Identifier: CC0-1.0
+
+module t;
+    m ();
+    m ();
+endmodule
+
+module m;
+endmodule

test_regress/t/t_preproc_inc_bad.out

@@ -1,4 +1,4 @@
-%Error: t/t_preproc_inc_inc_bad.vh:11:1: syntax error, unexpected endmodule, expecting IDENTIFIER or randomize
+%Error: t/t_preproc_inc_inc_bad.vh:11:1: syntax error, unexpected endmodule, expecting IDENTIFIER or '(' or randomize
    11 | endmodule
       | ^~~~~~~~~
         t/t_preproc_inc_bad.v:10:1: ... note: In file included from 't_preproc_inc_bad.v'

test_regress/t/t_udp_noname.out

@@ -1,4 +0,0 @@
-%Error: t/t_udp_noname.v:15:8: syntax error, unexpected '(', expecting IDENTIFIER or randomize
-   15 |    udp (o, a);
-      |        ^
-%Error: Exiting due to

test_regress/t/t_udp_noname.pl

@@ -11,13 +11,11 @@ if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); di
 scenarios(simulator => 1);
 
 compile(
-    expect_filename => $Self->{golden_filename},
-    fails => $Self->{vlt_all},  # Verilator unsupported, bug468"
     );
 
-#execute(
-#    check_finished => 1,
-#    );
+execute(
+    check_finished => 1,
+    );
 
 ok(1);
 1;

test_regress/t/t_udp_noname.v

@@ -10,20 +10,23 @@ module t (/*AUTOARG*/
    );
    input clk;
 
-   reg  a;
-   wire  o;
-   udp (o, a);
+   reg  a1;
+   wire a2 = ~a1;
+   wire o1, o2;
+   udp (o1, a1);
+   udp (o2, a2);
 
    integer cyc;  initial cyc = 0;
 
    // Test loop
    always @ (posedge clk) begin
       cyc <= cyc + 1;
-      a <= cyc[0];
+      a1  <= cyc[0];
       if (cyc==0) begin
       end
       else if (cyc<90) begin
-         if (a != !cyc[0]) $stop;
+         if (o1 !=  cyc[0]) $stop;
+         if (o2 != !cyc[0]) $stop;
       end
       else if (cyc==99) begin
          $write("*-* All Finished *-*\n");

test_regress/t/t_vams_kwd_bad.out

@@ -2,7 +2,7 @@
    12 |    int above;
       |        ^~~~~
                     ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
-%Error: t/t_vams_kwd_bad.v:12:13: syntax error, unexpected ';', expecting IDENTIFIER or randomize
+%Error: t/t_vams_kwd_bad.v:12:13: syntax error, unexpected ';', expecting IDENTIFIER or '(' or randomize
    12 |    int above;
       |             ^
 %Error-UNSUPPORTED: t/t_vams_kwd_bad.v:13:8: Unsupported: AMS reserved word not implemented: 'abs'