Support `specparam` (#5767).

Changes

@@ -19,6 +19,7 @@ Verilator 5.037 devel
 * Support SARIF JSON diagnostic output with `--diagnostics-sarif`. (#6017)
 * Support 1-bit params with -G and -pvalue (#6051) (#6082). [Paul Swirhun]
 * Support `$timeformat` with missing arguments (#6113). [Alex Solomatnikov]
+* Support `specparam` (#5767).
 * Support parameter forward types.
 * Add PROCINITASSIGN on initial assignments to process variables (#2481). [Niraj Menon]
 * Add BADVLTPRAGMA on unknown Verilator pragmas (#5945). [Shou-Li Hsu]

src/V3Ast.h

@@ -923,6 +923,7 @@ public:
         UNKNOWN,
         GPARAM,
         LPARAM,
+        SPECPARAM,
         GENVAR,
         VAR,  // Reg, integer, logic, etc
         SUPPLY0,
@@ -951,9 +952,10 @@ public:
     constexpr operator en() const { return m_e; }
     const char* ascii() const {
         static const char* const names[]
-            = {"?",    "GPARAM",    "LPARAM",     "GENVAR",   "VAR",     "SUPPLY0",  "SUPPLY1",
+            = {"?",        "GPARAM",  "LPARAM",   "SPECPARAM", "GENVAR",    "VAR",
-               "WIRE", "WREAL",     "TRIAND",     "TRIOR",    "TRIWIRE", "TRI0",     "TRI1",
+               "SUPPLY0",  "SUPPLY1", "WIRE",     "WREAL",     "TRIAND",    "TRIOR",
-               "PORT", "BLOCKTEMP", "MODULETEMP", "STMTTEMP", "XTEMP",   "IFACEREF", "MEMBER"};
+               "TRIWIRE",  "TRI0",    "TRI1",     "PORT",      "BLOCKTEMP", "MODULETEMP",
+               "STMTTEMP", "XTEMP",   "IFACEREF", "MEMBER"};
         return names[m_e];
     }
     bool isParam() const { return m_e == GPARAM || m_e == LPARAM; }
@@ -983,8 +985,8 @@ public:
         return (m_e == BLOCKTEMP || m_e == MODULETEMP || m_e == STMTTEMP || m_e == XTEMP);
     }
     bool isVPIAccessible() const {
-        return (m_e == VAR || m_e == GPARAM || m_e == LPARAM || m_e == PORT || m_e == WIRE
+        return (m_e == VAR || m_e == GPARAM || m_e == LPARAM || m_e == SPECPARAM || m_e == PORT
-                || m_e == TRI0 || m_e == TRI1);
+                || m_e == WIRE || m_e == TRI0 || m_e == TRI1);
     }
 
     const char* traceSigKind() const {
@@ -993,6 +995,7 @@ public:
             /* UNKNOWN:      */ "",  // Should not be traced
             /* GPARAM:       */ "PARAMETER",
             /* LPARAM:       */ "PARAMETER",
+            /* SPECPARAM:    */ "PARAMETER",
             /* GENVAR:       */ "PARAMETER",
             /* VAR:          */ "VAR",
             /* SUPPLY0:      */ "SUPPLY0",

src/V3ParseImp.cpp

@@ -688,7 +688,13 @@ void V3ParseImp::tokenPipelineSym() {
     int token = yylval.token;
     if (token == yaID__LEX || token == yaID__CC || token == yaID__aTYPE) {
         importIfInStd(yylval.fl, *(yylval.strp));
-        if (token == yaID__LEX) token = yaID__ETC;
+        if (token == yaID__LEX) {
+            if (VString::startsWith(*(yylval.strp), "PATHPULSE__024a")) {
+                token = yaID__PATHPULSE;
+            } else {
+                token = yaID__ETC;
+            }
+        }
     }
     m_afterColonColon = token == yP_COLONCOLON;
     yylval.token = token;

src/verilog.y

@@ -426,6 +426,7 @@ BISONPRE_VERSION(3.7,%define api.header.include {"V3ParseBison.h"})
 %token<strp>            yaID__ETC       "IDENTIFIER"
 %token<strp>            yaID__CC        "IDENTIFIER-::"
 %token<strp>            yaID__LEX       "IDENTIFIER-in-lex"
+%token<strp>            yaID__PATHPULSE "IDENTIFIER-for-pathpulse"
 %token<strp>            yaID__aINST     "IDENTIFIER-for-instance"
 %token<strp>            yaID__aTYPE     "IDENTIFIER-for-type"
 //                      Can't predecode aFUNCTION, can declare after use
@@ -5787,12 +5788,42 @@ specify_itemList<nodep>:            // IEEE: { specify_item }
         ;
 
 specify_item<nodep>:                // ==IEEE: specify_item
-                system_timing_check                     { $$ = $1; }
+                specparam_declaration                   { $$ = $1; }
+        |       system_timing_check                     { $$ = $1; }
         |       junkToSemiList ';'                      { $$ = nullptr; }
         ;
 
 specparam_declaration<nodep>:       // ==IEEE: specparam_declaration
-                ySPECPARAM junkToSemiList ';'           { $$ = nullptr; }
+                specparam_declarationFront list_of_specparam_assignments ';'
+                        { $$ = $2; }
+        ;
+
+specparam_declarationFront:     // IEEE: part of specparam_declaration
+        //                      // Front must execute first so VARDTYPE is ready before list of vars
+                ySPECPARAM
+                        { VARRESET_NONLIST(SPECPARAM);
+                          AstNodeDType* dtp = new AstBasicDType{$1, VBasicDTypeKwd::DOUBLE};
+                          VARDTYPE(dtp); }
+        |       ySPECPARAM packed_dimension
+                        { VARRESET_NONLIST(SPECPARAM);
+                          AstNodeDType* const dtp = GRAMMARP->addRange(
+                                    new AstBasicDType{$2->fileline(), LOGIC_IMPLICIT}, $2, true);
+                          VARDTYPE(dtp); }
+        ;
+
+list_of_specparam_assignments<varp>:  // ==IEEE: list_of_specparam_assignments
+                specparam_assignment                    { $$ = $1; }
+        |       list_of_specparam_assignments ',' specparam_assignment  { $$ = $1->addNext($3); }
+        ;
+
+specparam_assignment<varp>:     // ==IEEE: specparam_assignment
+                idNotPathpulse sigAttrListE '=' minTypMax
+                        { $$ = VARDONEA($<fl>1, *$1, nullptr, $2);
+                          if ($4) $$->valuep($4); }
+        //                      //  IEEE: pulse_control_specparam
+        |       idPathpulse sigAttrListE '=' '(' minTypMax ',' minTypMax ')'
+                        { $$ = VARDONEA($<fl>1, *$1, nullptr, $2);
+                          if ($5) $$->valuep($5); }
         ;
 
 system_timing_check<nodep>:         // ==IEEE: system_timing_check
@@ -5851,7 +5882,7 @@ junkToSemiList:
         ;
 
 junkToSemi:
-                BISONPRE_NOT(';',yENDSPECIFY,yENDMODULE,yD_SETUPHOLD)        { }
+                BISONPRE_NOT(';',yD_SETUPHOLD,yENDMODULE,yENDSPECIFY,ySPECPARAM)        { }
         |       error {}
         ;
 
@@ -5860,16 +5891,27 @@ junkToSemi:
 
 id<strp>:
                 yaID__ETC                               { $$ = $1; $<fl>$ = $<fl>1; }
+        |       yaID__PATHPULSE                         { $$ = $1; $<fl>$ = $<fl>1; }
         |       idRandomize                             { $$ = $1; $<fl>$ = $<fl>1; }
         ;
 
 idAny<strp>:  // Any kind of identifier
                 yaID__ETC                               { $$ = $1; $<fl>$ = $<fl>1; }
+        |       yaID__PATHPULSE                         { $$ = $1; $<fl>$ = $<fl>1; }
         |       yaID__aINST                             { $$ = $1; $<fl>$ = $<fl>1; }
         |       yaID__aTYPE                             { $$ = $1; $<fl>$ = $<fl>1; }
         |       idRandomize                             { $$ = $1; $<fl>$ = $<fl>1; }
         ;
 
+idNotPathpulse<strp>:  // Id excluding specparam PATHPULSE$, IEEE: part of specparam_assignment
+                yaID__ETC                               { $$ = $1; $<fl>$ = $<fl>1; }
+        |       idRandomize                             { $$ = $1; $<fl>$ = $<fl>1; }
+        ;
+
+idPathpulse<strp>:  // Id for specparam PATHPULSE$, IEEE: part of pulse_control_specparam
+                yaID__PATHPULSE                         { $$ = $1; $<fl>$ = $<fl>1; }
+        ;
+
 idAnyAsParseRef<parseRefp>:  // Any kind of identifier as a ParseRef
                 idAny
                         { $$ = new AstParseRef{$<fl>1, VParseRefExp::PX_TEXT, *$1}; }

test_regress/t/t_flag_wpedantic_bad.out

@@ -1,4 +1,4 @@
-%Error: t/t_flag_wpedantic_bad.v:8:8: syntax error, unexpected global, expecting IDENTIFIER or do or final or randomize
+%Error: t/t_flag_wpedantic_bad.v:8:8: syntax error, unexpected global
     8 |    reg global;
       |        ^~~~~~
         ... See the manual at https://verilator.org/verilator_doc.html?v=latest for more assistance.

test_regress/t/t_lint_pkg_colon_bad.out

@@ -1,4 +1,4 @@
-%Error: t/t_lint_pkg_colon_bad.v:8:8: syntax error, unexpected IDENTIFIER-::, expecting IDENTIFIER or do or final or randomize
+%Error: t/t_lint_pkg_colon_bad.v:8:8: syntax error, unexpected IDENTIFIER-::
     8 |    reg mispkgb::bar_t b;
       |        ^~~~~~~
         ... See the manual at https://verilator.org/verilator_doc.html?v=latest for more assistance.

test_regress/t/t_param_type_bad.out

@@ -1,4 +1,4 @@
-%Error: t/t_param_type_bad.v:9:27: syntax error, unexpected INTEGER NUMBER, expecting IDENTIFIER or IDENTIFIER-for-instance or IDENTIFIER-for-type or randomize
+%Error: t/t_param_type_bad.v:9:27: syntax error, unexpected INTEGER NUMBER
     9 |    localparam type bad2 = 2;   
       |                           ^
         ... See the manual at https://verilator.org/verilator_doc.html?v=latest for more assistance.

test_regress/t/t_pp_circ_subst_bad.out

@@ -1,4 +1,4 @@
 %Error: t/t_pp_circ_subst_bad.v:8:80001: Too many preprocessor tokens on a line (>40000); perhaps recursive `define
         ... See the manual at https://verilator.org/verilator_doc.html?v=latest for more assistance.
-%Error: t/t_pp_circ_subst_bad.v:8:5: syntax error, unexpected IDENTIFIER-for-type, expecting IDENTIFIER or do or final or randomize
+%Error: t/t_pp_circ_subst_bad.v:8:5: syntax error, unexpected IDENTIFIER-for-type
 %Error: Exiting due to

test_regress/t/t_pp_circ_subst_bad2.out

@@ -1,4 +1,4 @@
 %Error: t/t_pp_circ_subst_bad.v:8:40002: Too many preprocessor tokens on a line (>20000); perhaps recursive `define
         ... See the manual at https://verilator.org/verilator_doc.html?v=latest for more assistance.
-%Error: t/t_pp_circ_subst_bad.v:8:5: syntax error, unexpected IDENTIFIER-for-type, expecting IDENTIFIER or do or final or randomize
+%Error: t/t_pp_circ_subst_bad.v:8:5: syntax error, unexpected IDENTIFIER-for-type
 %Error: Exiting due to

test_regress/t/t_specparam.py

@@ -11,6 +11,8 @@ import vltest_bootstrap
 
 test.scenarios('vlt')
 
-test.lint(fails=True, expect_filename=test.golden_filename)
+test.compile(verilator_flags2=['--binary'])
+
+test.execute()
 
 test.passes()

test_regress/t/t_specparam.v

@@ -0,0 +1,44 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2025 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t;
+  specify
+    specparam tdevice_PU = 3e8;
+    specparam Tdelay11 = 1.1;
+    // verilator lint_off MINTYPMAXDLY
+    specparam Tmintypmax = 1.0:1.1:1.2;
+    specparam PATHPULSE$a$b = (3.0:3.1:3.2, 4.0:4.1:4.2);
+    specparam randomize = 1;  // Special parser corner-case
+  endspecify
+
+  // Support in other simulators is limited for module specparams
+  specparam Tmod34 = 3.4, Tmod35 = 3.5;  // IEEE 6.20.5 allowed in body
+  // Support in other simulators is limited for ranged specparams
+  specparam [5:2] Tranged = 4'b1011;
+
+  localparam real PATHPULSE$normal$var = 6.78;
+
+  reg PoweredUp;
+  wire DelayIn, DelayOut;
+
+  assign #tdevice_PU DelayOut = DelayIn;
+
+  initial begin
+    PoweredUp = 1'b0;
+    #tdevice_PU PoweredUp = 1'b1;
+    if (Tdelay11 != 1.1) $stop;
+`ifdef VERILATOR
+    if (Tmintypmax != 1.1) $stop;
+    if (PATHPULSE$a$b != 3.1) $stop;
+`endif
+    if (Tranged != 4'b1011) $stop;
+    if (Tmod34 != 3.4) $stop;
+    if (Tmod35 != 3.5) $stop;
+    if (PATHPULSE$normal$var != 6.78) $stop;
+    $write("*-* All Finished *-*\n");
+    $finish;
+  end
+endmodule

test_regress/t/t_specparam_unsup.out

@@ -1,5 +0,0 @@
-%Error: t/t_specparam_unsup.v:14:8: Can't find definition of variable: 'tdevice_PU'
-   14 |       #tdevice_PU PoweredUp = 1'b1;
-      |        ^~~~~~~~~~
-        ... See the manual at https://verilator.org/verilator_doc.html?v=latest for more assistance.
-%Error: Exiting due to

test_regress/t/t_specparam_unsup.v

@@ -1,16 +0,0 @@
-// DESCRIPTION: Verilator: Verilog Test module
-//
-// This file ONLY is placed under the Creative Commons Public Domain, for
-// any use, without warranty, 2025 by Wilson Snyder.
-// SPDX-License-Identifier: CC0-1.0
-
-module t ();
-   reg PoweredUp;
-   specify
-      specparam tdevice_PU = 3e8;
-   endspecify
-   initial begin
-      PoweredUp = 1'b0;
-      #tdevice_PU PoweredUp = 1'b1;
-   end
-endmodule