Internals: Determine needing verilated_std without symbol table

include/verilated_std.sv

@@ -21,6 +21,9 @@
 /// It is only for internal use.
 ///
 //*************************************************************************
+//
+// The following keywords from this file are hardcoded for detection in the parser:
+// "mailbox", "process", "randomize", "semaphore", "std"
 
 // verilator lint_off DECLFILENAME
 // verilator lint_off TIMESCALEMOD

src/Makefile_obj.in

@@ -142,6 +142,8 @@ BISONPRE = $(srcdir)/bisonpre
 FLEXFIX = $(srcdir)/flexfix
 VLCOVGEN = $(srcdir)/vlcovgen
 
+# BISON_DEBUG = -Wcounterexamples
+
 ######################################################################
 # CCACHE flags (via environment as no command line option available)
 CCACHE_SLOPPINESS ?= pch_defines,time_macros
@@ -417,7 +419,7 @@ V3ParseBison.h: V3ParseBison.c
 # Have only one output file in this rule to prevent parallel make issues
 V3ParseBison.c: verilog.y $(BISONPRE)
 	@echo "If you get errors from verilog.y below, try upgrading bison to version 1.875 or newer."
-	$(PYTHON3) $(BISONPRE) --yacc ${YACC} -d -v -o V3ParseBison.c $<
+	$(PYTHON3) $(BISONPRE) --yacc ${YACC} -d -v -o V3ParseBison.c $(BISON_DEBUG) $<
 
 V3Lexer_pregen.yy.cpp: verilog.l V3ParseBison.h $(HEADERS)
 	${LEX} --version

src/V3ParseImp.cpp

@@ -70,6 +70,25 @@ V3ParseImp::~V3ParseImp() {
 //######################################################################
 // Parser utility methods
 
+void V3ParseImp::importIfInStd(FileLine* fileline, const string& id) {
+    // Keywords that auto-import to require use of verilated_std.vh.
+    // OK if overly sensitive; will over-import and keep std:: around
+    // longer than migt otherwise.
+    if (v3Global.usesStdPackage()) return;  // Run once then short-circuit
+    const bool identifierImportsStd = (id == "mailbox" || id == "process" || id == "randomize"
+                                       || id == "semaphore" || id == "std");
+    if (!identifierImportsStd) return;
+    // Ignore Std:: used inside verilated_std.vh itself
+    if (fileline->filename() == V3Options::getStdPackagePath()) return;
+    if (AstPackage* const stdpkgp
+        = v3Global.rootp()->stdPackagep()) {  // else e.g. --no-std-package
+        UINFO(9, "import and keep std:: for " << fileline << "\n");
+        AstPackageImport* const impp = new AstPackageImport{stdpkgp->fileline(), stdpkgp, "*"};
+        unitPackage(stdpkgp->fileline())->addStmtsp(impp);
+        v3Global.setUsesStdPackage();
+    }
+}
+
 void V3ParseImp::lexPpline(const char* textp) {
     // Handle lexer `line directive
     // FileLine* const prevFl = lexFileline();
@@ -647,6 +666,9 @@ void V3ParseImp::tokenPipelineSym() {
     // Note above sometimes converts yGLOBAL to a yaID__LEX
     tokenPipeline();  // sets yylval
     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__CC) {
         const VSymEnt* foundp;
         if (const VSymEnt* const look_underp = V3ParseImp::parsep()->symp()->nextId()) {
@@ -669,12 +691,6 @@ void V3ParseImp::tokenPipelineSym() {
                 VSymEnt* const stdsymp = stdpkgp->user4u().toSymEnt();
                 foundp = stdsymp->findIdFallback(*(yylval.strp));
             }
-            if (foundp && !v3Global.usesStdPackage()) {
-                AstPackageImport* const impp
-                    = new AstPackageImport{stdpkgp->fileline(), stdpkgp, "*"};
-                unitPackage(stdpkgp->fileline())->addStmtsp(impp);
-                v3Global.setUsesStdPackage();
-            }
         }
         if (foundp) {
             AstNode* const scp = foundp->nodep();
@@ -692,8 +708,6 @@ void V3ParseImp::tokenPipelineSym() {
                 } else {
                     token = yaID__ETC;
                 }
-            } else if (!m_afterColonColon && *(yylval.strp) == "std") {
-                v3Global.setUsesStdPackage();
             }
         } else {  // Not found
             yylval.scp = nullptr;

src/V3ParseImp.h

@@ -309,6 +309,7 @@ private:
     void preprocDumps(std::ostream& os);
     void lexFile(const string& modname) VL_MT_DISABLED;
     void yylexReadTok() VL_MT_DISABLED;
+    void importIfInStd(FileLine* fileline, const string& id);
     void tokenPull() VL_MT_DISABLED;
     void tokenPipeline() VL_MT_DISABLED;  // Internal; called from tokenToBison
     int tokenPipelineId(int token) VL_MT_DISABLED;

test_regress/t/t_dump_json.out

@@ -519,14 +519,14 @@
  "miscsp": [
   {"type":"TYPETABLE","name":"","addr":"(C)","loc":"a,0:0,0:0","constraintRefp":"UNLINKED","emptyQueuep":"UNLINKED","queueIndexp":"UNLINKED","streamp":"UNLINKED","voidp":"(HI)",
    "typesp": [
-    {"type":"BASICDTYPE","name":"integer","addr":"(II)","loc":"d,31:27,31:28","dtypep":"(II)","keyword":"integer","range":"31:0","generic":true,"rangep": []},
+    {"type":"BASICDTYPE","name":"integer","addr":"(II)","loc":"d,34:27,34:28","dtypep":"(II)","keyword":"integer","range":"31:0","generic":true,"rangep": []},
-    {"type":"BASICDTYPE","name":"logic","addr":"(L)","loc":"d,33:32,33:33","dtypep":"(L)","keyword":"logic","range":"31:0","generic":true,"rangep": []},
+    {"type":"BASICDTYPE","name":"logic","addr":"(L)","loc":"d,36:32,36:33","dtypep":"(L)","keyword":"logic","range":"31:0","generic":true,"rangep": []},
-    {"type":"BASICDTYPE","name":"logic","addr":"(UE)","loc":"d,50:22,50:24","dtypep":"(UE)","keyword":"logic","generic":true,"rangep": []},
+    {"type":"BASICDTYPE","name":"logic","addr":"(UE)","loc":"d,53:22,53:24","dtypep":"(UE)","keyword":"logic","generic":true,"rangep": []},
-    {"type":"VOIDDTYPE","name":"","addr":"(HI)","loc":"d,51:21,51:30","dtypep":"(HI)","generic":false},
+    {"type":"VOIDDTYPE","name":"","addr":"(HI)","loc":"d,54:21,54:30","dtypep":"(HI)","generic":false},
-    {"type":"BASICDTYPE","name":"logic","addr":"(QD)","loc":"d,125:22,125:23","dtypep":"(QD)","keyword":"logic","range":"31:0","generic":true,"rangep": []},
+    {"type":"BASICDTYPE","name":"logic","addr":"(QD)","loc":"d,128:22,128:23","dtypep":"(QD)","keyword":"logic","range":"31:0","generic":true,"rangep": []},
-    {"type":"BASICDTYPE","name":"logic","addr":"(JI)","loc":"d,127:22,127:23","dtypep":"(JI)","keyword":"logic","range":"31:0","generic":true,"rangep": []},
+    {"type":"BASICDTYPE","name":"logic","addr":"(JI)","loc":"d,130:22,130:23","dtypep":"(JI)","keyword":"logic","range":"31:0","generic":true,"rangep": []},
-    {"type":"BASICDTYPE","name":"logic","addr":"(KI)","loc":"d,162:17,162:56","dtypep":"(KI)","keyword":"logic","range":"295:0","generic":true,"rangep": []},
+    {"type":"BASICDTYPE","name":"logic","addr":"(KI)","loc":"d,165:17,165:56","dtypep":"(KI)","keyword":"logic","range":"295:0","generic":true,"rangep": []},
-    {"type":"BASICDTYPE","name":"string","addr":"(BG)","loc":"d,162:10,162:16","dtypep":"(BG)","keyword":"string","generic":true,"rangep": []},
+    {"type":"BASICDTYPE","name":"string","addr":"(BG)","loc":"d,165:10,165:16","dtypep":"(BG)","keyword":"string","generic":true,"rangep": []},
     {"type":"BASICDTYPE","name":"logic","addr":"(Q)","loc":"e,14:9,14:11","dtypep":"(Q)","keyword":"logic","range":"31:0","generic":true,"rangep": []},
     {"type":"BASICDTYPE","name":"logic","addr":"(BB)","loc":"e,18:10,18:12","dtypep":"(BB)","keyword":"logic","range":"31:0","generic":true,"rangep": []},
     {"type":"BASICDTYPE","name":"logic","addr":"(MC)","loc":"e,33:26,33:31","dtypep":"(MC)","keyword":"logic","range":"31:0","generic":true,"rangep": []},

test_regress/t/t_std_identifier.py

@@ -11,6 +11,6 @@ import vltest_bootstrap
 
 test.scenarios('linter')
 
-test.lint(verilator_flags2=["-DTEST_DECLARE_STD"])
+test.lint(verilator_flags2=["-DTEST_DECLARE_STD"], fails=test.vlt_all)  # Issue #4705 due to ::
 
 test.passes()