Add zero-arity funclike #define

chibicc.h

@@ -73,6 +73,7 @@ struct Token {
   File *file;       // Source location
   int line_no;      // Line number
   bool at_bol;      // True if this token is at beginning of line
+  bool has_space;   // True if this token follows a space character
   Hideset *hideset; // For macro expansion
 };
 

main.c

@@ -179,7 +179,9 @@ static void print_tokens(Token *tok) {
   for (; tok->kind != TK_EOF; tok = tok->next) {
     if (line > 1 && tok->at_bol)
       fprintf(out, "\n");
-    fprintf(out, " %.*s", tok->len, tok->loc);
+    if (tok->has_space && !tok->at_bol)
+      fprintf(out, " ");
+    fprintf(out, "%.*s", tok->len, tok->loc);
     line++;
   }
   fprintf(out, "\n");

preprocess.c

@@ -27,6 +27,7 @@ typedef struct Macro Macro;
 struct Macro {
   Macro *next;
   char *name;
+  bool is_objlike; // Object-like or function-like
   Token *body;
   bool deleted;
 };
@@ -215,15 +216,32 @@ static Macro *find_macro(Token *tok) {
   return NULL;
 }
 
-static Macro *add_macro(char *name, Token *body) {
+static Macro *add_macro(char *name, bool is_objlike, Token *body) {
   Macro *m = calloc(1, sizeof(Macro));
   m->next = macros;
   m->name = name;
+  m->is_objlike = is_objlike;
   m->body = body;
   macros = m;
   return m;
 }
 
+static void read_macro_definition(Token **rest, Token *tok) {
+  if (tok->kind != TK_IDENT)
+    error_tok(tok, "macro name must be an identifier");
+  char *name = strndup(tok->loc, tok->len);
+  tok = tok->next;
+
+  if (!tok->has_space && equal(tok, "(")) {
+    // Function-like macro
+    tok = skip(tok->next, ")");
+    add_macro(name, false, copy_line(rest, tok));
+  } else {
+    // Object-like macro
+    add_macro(name, true, copy_line(rest, tok));
+  }
+}
+
 // If tok is a macro, expand it and return true.
 // Otherwise, do nothing and return false.
 static bool expand_macro(Token **rest, Token *tok) {
@@ -234,9 +252,22 @@ static bool expand_macro(Token **rest, Token *tok) {
   if (!m)
     return false;
 
-  Hideset *hs = hideset_union(tok->hideset, new_hideset(m->name));
-  Token *body = add_hideset(m->body, hs);
-  *rest = append(body, tok->next);
+  // Object-like macro application
+  if (m->is_objlike) {
+    Hideset *hs = hideset_union(tok->hideset, new_hideset(m->name));
+    Token *body = add_hideset(m->body, hs);
+    *rest = append(body, tok->next);
+    return true;
+  }
+
+  // If a funclike macro token is not followed by an argument list,
+  // treat it as a normal identifier.
+  if (!equal(tok->next, "("))
+    return false;
+
+  // Function-like macro application
+  tok = skip(tok->next->next, ")");
+  *rest = append(m->body, tok);
   return true;
 }
 
@@ -282,11 +313,7 @@ static Token *preprocess2(Token *tok) {
     }
 
     if (equal(tok, "define")) {
-      tok = tok->next;
-      if (tok->kind != TK_IDENT)
-        error_tok(tok, "macro name must be an identifier");
-      char *name = strndup(tok->loc, tok->len);
-      add_macro(name, copy_line(&tok, tok->next));
+      read_macro_definition(&tok, tok->next);
       continue;
     }
 
@@ -297,7 +324,7 @@ static Token *preprocess2(Token *tok) {
       char *name = strndup(tok->loc, tok->len);
       tok = skip_line(tok->next);
 
-      Macro *m = add_macro(name, NULL);
+      Macro *m = add_macro(name, true, NULL);
       m->deleted = true;
       continue;
     }

test/macro.c

@@ -10,6 +10,8 @@ int memcmp(char *p, char *q, long n);
 
 /* */ #
 
+int ret3(void) { return 3; }
+
 int main() {
   assert(5, include1, "include1");
   assert(7, include2, "include2");
@@ -194,6 +196,14 @@ int main() {
 #else
 #endif
 
+#define M7() 1
+  int M7 = 5;
+  assert(1, M7(), "M7()");
+  assert(5, M7, "M7");
+
+#define M7 ()
+  assert(3, ret3 M7, "ret3 M7");
+
   printf("OK\n");
   return 0;
 }

tokenize.c

@@ -9,6 +9,9 @@ static File **input_files;
 // True if the current position is at the beginning of a line
 static bool at_bol;
 
+// True if the current position follows a space character
+static bool has_space;
+
 // Reports an error and exit.
 void error(char *fmt, ...) {
   va_list ap;
@@ -101,7 +104,9 @@ static Token *new_token(TokenKind kind, char *start, char *end) {
   tok->len = end - start;
   tok->file = current_file;
   tok->at_bol = at_bol;
-  at_bol = false;
+  tok->has_space = has_space;
+
+  at_bol = has_space = false;
   return tok;
 }
 
@@ -394,6 +399,7 @@ static Token *tokenize(File *file) {
   Token *cur = &head;
 
   at_bol = true;
+  has_space = false;
 
   while (*p) {
     // Skip line comments.
@@ -401,6 +407,7 @@ static Token *tokenize(File *file) {
       p += 2;
       while (*p != '\n')
         p++;
+      has_space = true;
       continue;
     }
 
@@ -410,6 +417,7 @@ static Token *tokenize(File *file) {
       if (!q)
         error_at(p, "unclosed block comment");
       p = q + 2;
+      has_space = true;
       continue;
     }
 
@@ -417,12 +425,14 @@ static Token *tokenize(File *file) {
     if (*p == '\n') {
       p++;
       at_bol = true;
+      has_space = false;
       continue;
     }
 
     // Skip whitespace characters.
     if (isspace(*p)) {
       p++;
+      has_space = true;
       continue;
     }