Fix stringify in nested preprocessor macros (#5323)

src/V3PreProc.cpp

@@ -1326,8 +1326,8 @@ int V3PreProcImp::getStateToken() {
                     // NOP: out = m_preprocp->defSubstitute(out);
                 }
                 VL_DO_DANGLING(m_defRefs.pop(), refp);
-                if (m_defRefs.empty()) {
+                statePop();
-                    statePop();
+                if (m_defRefs.empty() || state() == ps_STRIFY || state() == ps_JOIN) {
                     if (state()
                         == ps_JOIN) {  // Handle {left}```FOO(ARG) where `FOO(ARG) might be empty
                         UASSERT(!m_joinStack.empty(), "`` join stack empty, but in a ``");
@@ -1345,7 +1345,8 @@ int V3PreProcImp::getStateToken() {
                         unputDefrefString("__IF_OFF_IGNORED_DEFINE");
                     }
                     m_lexp->m_parenLevel = 0;
-                } else {  // Finished a defref inside a upper defref
+                } else {  // Finished a defref inside a upper defref,
+                          // and not under stringification or join.
                     // Can't subst now, or
                     // `define a(ign) x,y
                     // foo(`a(ign),`b)  would break because a contains comma
@@ -1353,7 +1354,7 @@ int V3PreProcImp::getStateToken() {
                     refp->nextarg(refp->nextarg() + m_lexp->m_defValue + out);
                     m_lexp->m_defValue = "";
                     m_lexp->m_parenLevel = refp->parenLevel();
-                    statePop();  // Will go to ps_DEFARG, as we're under another define
+                    // Will go to ps_DEFARG, as we're under another define
                 }
                 goto next_tok;
             } else if (tok == VP_DEFREF) {
@@ -1551,7 +1552,7 @@ int V3PreProcImp::getStateToken() {
                     }
                     // Similar code in parenthesized define (Search for END_OF_DEFARG)
                     // NOP: out = m_preprocp->defSubstitute(out);
-                    if (m_defRefs.empty()) {
+                    if (m_defRefs.empty() || state() == ps_STRIFY || state() == ps_JOIN) {
                         // Just output the substitution
                         if (state() == ps_JOIN) {  // Handle {left}```FOO where `FOO might be empty
                             UASSERT(!m_joinStack.empty(), "`` join stack empty, but in a ``");
@@ -1569,7 +1570,7 @@ int V3PreProcImp::getStateToken() {
                             unputDefrefString("__IF_OFF_IGNORED_DEFINE");
                         }
                     } else {
-                        // Inside another define.
+                        // Inside another define, and not under stringification or join.
                         // Can't subst now, or
                         // `define a x,y
                         // foo(`a,`b)  would break because a contains comma

test_regress/t/t_preproc.out

@@ -1065,3 +1065,17 @@ predef 2 2
  
 
 `line 744 "t/t_preproc.v" 0
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+string boo = "test";
+string boo = "test x,y x,y";
+string boo = "testx,ytest x x,y";
+string boo = "testtest x,y xquux(test)";
+
+`line 757 "t/t_preproc.v" 0

test_regress/t/t_preproc.v

@@ -740,3 +740,16 @@ predef `SV_COV_PARTIAL 2
 //======================================================================
 // After `undefineall above, for testing --dump-defines
 `define WITH_ARG(a) (a)(a)
+
+//======================================================================
+// Stringify in nested macro
+`define foo test
+`define a x,y
+`define bar(a, b) test a b
+`define baz(a, b) test``a``b
+`define qux(x) string boo = x;
+`define quux(x) `qux(`"x`")
+`quux(`foo)
+`quux(`bar(`a,`a))
+`quux(`baz(`a,`bar(x,`a)))
+`quux(`baz(`bar(`a,x), quux(`foo)))

test_regress/t/t_preproc_comments.out

@@ -1070,3 +1070,17 @@ predef 2 2
  
 
 `line 744 "t/t_preproc.v" 0
+//====================================================================== 
+// Stringify in nested macro 
+ 
+ 
+ 
+ 
+ 
+ 
+string boo = "test";
+string boo = "test x,y x,y";
+string boo = "testx,ytest x x,y";
+string boo = "testtest x,y xquux(test)";
+
+`line 757 "t/t_preproc.v" 0

test_regress/t/t_preproc_defines.out

@@ -20,6 +20,12 @@
 `define TEST_OBJ_DIR obj_vlt/t_preproc_defines
 `define VERILATOR 1
 `define WITH_ARG(a) (a)(a)
+`define a x,y
+`define bar(a, b) test a b
+`define baz(a, b) test``a``b
 `define coverage_block_off /*verilator coverage_block_off*/
+`define foo test
+`define quux(x) `qux(`"x`")
+`define qux(x) string boo = x;
 `define verilator 1
 `define verilator3 1