[GNU] Support GCC-style variadic macro

preprocess.c

@@ -34,6 +34,7 @@ typedef struct MacroArg MacroArg;
 struct MacroArg {
   MacroArg *next;
   char *name;
+  bool is_va_args;
   Token *tok;
 };
 
@@ -45,7 +46,7 @@ struct Macro {
   char *name;
   bool is_objlike; // Object-like or function-like
   MacroParam *params;
-  bool is_variadic;
+  char *va_args_name;
   Token *body;
   bool deleted;
   macro_handler_fn *handler;
@@ -349,7 +350,7 @@ static Macro *add_macro(char *name, bool is_objlike, Token *body) {
   return m;
 }
 
-static MacroParam *read_macro_params(Token **rest, Token *tok, bool *is_variadic) {
+static MacroParam *read_macro_params(Token **rest, Token *tok, char **va_args_name) {
   MacroParam head = {};
   MacroParam *cur = &head;
 
@@ -358,13 +359,20 @@ static MacroParam *read_macro_params(Token **rest, Token *tok, bool *is_variadic
       tok = skip(tok, ",");
 
     if (equal(tok, "...")) {
-      *is_variadic = true;
+      *va_args_name = "__VA_ARGS__";
       *rest = skip(tok->next, ")");
       return head.next;
     }
 
     if (tok->kind != TK_IDENT)
       error_tok(tok, "expected an identifier");
+
+    if (equal(tok->next, "...")) {
+      *va_args_name = strndup(tok->loc, tok->len);
+      *rest = skip(tok->next->next, ")");
+      return head.next;
+    }
+
     MacroParam *m = calloc(1, sizeof(MacroParam));
     m->name = strndup(tok->loc, tok->len);
     cur = cur->next = m;
@@ -383,12 +391,12 @@ static void read_macro_definition(Token **rest, Token *tok) {
 
   if (!tok->has_space && equal(tok, "(")) {
     // Function-like macro
-    bool is_variadic = false;
-    MacroParam *params = read_macro_params(&tok, tok->next, &is_variadic);
+    char *va_args_name = NULL;
+    MacroParam *params = read_macro_params(&tok, tok->next, &va_args_name);
 
     Macro *m = add_macro(name, false, copy_line(rest, tok));
     m->params = params;
-    m->is_variadic = is_variadic;
+    m->va_args_name = va_args_name;
   } else {
     // Object-like macro
     add_macro(name, true, copy_line(rest, tok));
@@ -427,7 +435,7 @@ static MacroArg *read_macro_arg_one(Token **rest, Token *tok, bool read_rest) {
 }
 
 static MacroArg *
-read_macro_args(Token **rest, Token *tok, MacroParam *params, bool is_variadic) {
+read_macro_args(Token **rest, Token *tok, MacroParam *params, char *va_args_name) {
   Token *start = tok;
   tok = tok->next->next;
 
@@ -442,7 +450,7 @@ read_macro_args(Token **rest, Token *tok, MacroParam *params, bool is_variadic)
     cur->name = pp->name;
   }
 
-  if (is_variadic) {
+  if (va_args_name) {
     MacroArg *arg;
     if (equal(tok, ")")) {
       arg = calloc(1, sizeof(MacroArg));
@@ -452,7 +460,8 @@ read_macro_args(Token **rest, Token *tok, MacroParam *params, bool is_variadic)
         tok = skip(tok, ",");
       arg = read_macro_arg_one(&tok, tok, true);
     }
-    arg->name = "__VA_ARGS__";
+    arg->name = va_args_name;;
+    arg->is_va_args = true;
     cur = cur->next = arg;
   } else if (pp) {
     error_tok(start, "too many arguments");
@@ -545,7 +554,7 @@ static Token *subst(Token *tok, MacroArg *args) {
     // __VA_ARGS__.
     if (equal(tok, ",") && equal(tok->next, "##")) {
       MacroArg *arg = find_arg(args, tok->next->next);
-      if (arg && !strcmp(arg->name, "__VA_ARGS__")) {
+      if (arg && arg->is_va_args) {
         if (arg->tok->kind == TK_EOF) {
           tok = tok->next->next->next;
         } else {
@@ -671,7 +680,7 @@ static bool expand_macro(Token **rest, Token *tok) {
 
   // Function-like macro application
   Token *macro_token = tok;
-  MacroArg *args = read_macro_args(&tok, tok, m->params, m->is_variadic);
+  MacroArg *args = read_macro_args(&tok, tok, m->params, m->va_args_name);
   Token *rparen = tok;
 
   // Tokens that consist a func-like macro invocation may have different

test/macro.c

@@ -359,9 +359,28 @@ int main() {
 #define M14(x, ...) add6(1,2,x,__VA_ARGS__,6)
   ASSERT(21, M14(3,4,5));
 
+#define M14(args...) 3
+  ASSERT(3, M14());
+
 #define M14(x, ...) x
   ASSERT(5, M14(5));
 
+#define M14(args...) args
+  ASSERT(2, M14() 2);
+  ASSERT(5, M14(5));
+
+#define M14(args...) add2(args)
+  ASSERT(8, M14(2, 6));
+
+#define M14(args...) add6(1,2,args,6)
+  ASSERT(21, M14(3,4,5));
+
+#define M14(x, args...) add6(1,2,x,args,6)
+  ASSERT(21, M14(3,4,5));
+
+#define M14(x, args...) x
+  ASSERT(5, M14(5));
+
 #define CONCAT(x,y) x##y
   ASSERT(5, ({ int f0zz=5; CONCAT(f,0zz); }));
   ASSERT(5, ({ CONCAT(4,.57) + 0.5; }));