From 4ec75b261854f0013781e515678c3f79de884fa1 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Tue, 24 Sep 2024 18:53:32 -0400
Subject: [PATCH] Fix over-permissive parsing of UDPs without identifiers

---
 src/V3ParseImp.cpp                   |  3 ++-
 src/verilog.y                        | 20 ++++++++++++++------
 test_regress/t/t_preproc_inc_bad.out |  2 +-
 test_regress/t/t_vams_kwd_bad.out    |  2 +-
 4 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/src/V3ParseImp.cpp b/src/V3ParseImp.cpp
index ea60f2061..fc6d979df 100644
--- a/src/V3ParseImp.cpp
+++ b/src/V3ParseImp.cpp
@@ -656,7 +656,8 @@ int V3ParseImp::tokenToBison() {
     m_bisonLastFileline = yylval.fl;
 
     // yylval.scp = nullptr;   // Symbol table not yet needed - no packages
-    if (debugFlex() >= 6 || debugBison() >= 6) {  // --debugi-flex and --debugi-bison
+    if (debug() >= 6 || debugFlex() >= 6
+        || debugBison() >= 6) {  // --debugi-flex and --debugi-bison
         cout << "tokenToBison  " << yylval << endl;
     }
     return yylval.token;
diff --git a/src/verilog.y b/src/verilog.y
index 1f2b62e3f..18be2aba6 100644
--- a/src/verilog.y
+++ b/src/verilog.y
@@ -3242,7 +3242,9 @@ instDecl<nodep>:
         //                      // Currently disambiguated from data_declaration based on
         //                      // VARs being type, and cells non-type.
         //                      // IEEE requires a '(' to disambiguate, we need TODO force this
-                id parameter_value_assignmentE {INSTPREP($<fl>1, *$1, $2);} instnameList ';'
+                id parameter_value_assignmentE
+        /*mid*/         { INSTPREP($<fl>1, *$1, $2); }
+        /*cont*/    instnameList ';'
                         { $$ = $4;
                           GRAMMARP->m_impliedDecl = false;
                           if (GRAMMARP->m_instParamp) {
@@ -3257,6 +3259,12 @@ instDecl<nodep>:
         /*cont*/    mpInstnameList ';'
                         { $$ = VARDONEP($5, nullptr, nullptr); }
         //UNSUP: strengthSpecE for udp_instantiations
+        //                      // IEEE: part of udp_instance when no name_of_instance
+        //                      // Note no unpacked dimension nor list of instances
+        |       id
+        /*mid*/         { INSTPREP($<fl>1, *$1, nullptr); }
+        /*cont*/    instnameParenUdpn ';'
+                        { $$ = $3; GRAMMARP->m_impliedDecl = false; }
         ;
 
 mpInstnameList<nodep>:          // Similar to instnameList, but for modport instantiations which have no parenthesis
@@ -3278,7 +3286,10 @@ instnameParen<nodep>:
                         { $$ = GRAMMARP->createCellOrIfaceRef($<fl>1, *$1, $4, $2, true); }
         |       id instRangeListE
                         { $$ = GRAMMARP->createCellOrIfaceRef($<fl>1, *$1, nullptr, $2, false); }
-        |       '(' cellpinListE ')'  // When UDP has empty name, unpacked dimensions must not be used
+        ;
+
+instnameParenUdpn<nodep>:  // IEEE: part of udp_instance when no name_of_instance
+                '(' cellpinListE ')'  // When UDP has empty name, unpacked dimensions must not be used
                         { $$ = GRAMMARP->createCellOrIfaceRef($<fl>1, "", $2, nullptr, true); }
         ;
 
@@ -4607,7 +4618,7 @@ taskId<nodeFTaskp>:
                           SYMP->pushNewUnderNodeOrCurrent($$, $<scp>1); }
         ;
 
-funcId<nodeFTaskp>:                     // IEEE: function_data_type_or_implicit + part of function_body_declaration
+funcId<nodeFTaskp>:             // IEEE: function_data_type_or_implicit + part of function_body_declaration
         //                      // IEEE: function_data_type_or_implicit must be expanded here to prevent conflict
         //                      // function_data_type expanded here to prevent conflicts with
         //                      // implicit_type:empty vs data_type:ID
@@ -6552,9 +6563,6 @@ boolean_abbrev<nodeExprp>:  // ==IEEE: boolean_abbrev
                         { $$ = $2; BBUNSUP($<fl>1, "Unsupported: [-> boolean abbrev expression"); }
         ;
 
-//************************************************
-// Let
-
 //************************************************
 // Covergroup
 
diff --git a/test_regress/t/t_preproc_inc_bad.out b/test_regress/t/t_preproc_inc_bad.out
index 2f46dacbd..006f0ec09 100644
--- a/test_regress/t/t_preproc_inc_bad.out
+++ b/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 '(' or randomize
+%Error: t/t_preproc_inc_inc_bad.vh:11:1: syntax error, unexpected endmodule, expecting IDENTIFIER or randomize
    11 | endmodule
       | ^~~~~~~~~
         t/t_preproc_inc_bad.v:10:1: ... note: In file included from 't_preproc_inc_bad.v'
diff --git a/test_regress/t/t_vams_kwd_bad.out b/test_regress/t/t_vams_kwd_bad.out
index 9e3a97617..0d6fac32e 100644
--- a/test_regress/t/t_vams_kwd_bad.out
+++ b/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 '(' or randomize
+%Error: t/t_vams_kwd_bad.v:12:13: syntax error, unexpected ';', expecting IDENTIFIER or randomize
    12 |    int above;
       |             ^
 %Error-UNSUPPORTED: t/t_vams_kwd_bad.v:13:8: Unsupported: AMS reserved word not implemented: 'abs'