From 8e19cadfd6de3db6b4cd025be8a6028071a83dd6 Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@cs.stanford.edu>
Date: Thu, 27 Aug 2020 22:05:29 +0900
Subject: [PATCH] Allow to call a variadic function

---
 chibicc.h       |  1 +
 parse.c         | 11 ++++++++++-
 test/common     | 10 ++++++++++
 test/function.c |  7 +++++++
 test/test.h     |  4 ++--
 tokenize.c      |  3 ++-
 6 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/chibicc.h b/chibicc.h
index fa3cec2..cffbf5f 100644
--- a/chibicc.h
+++ b/chibicc.h
@@ -243,6 +243,7 @@ struct Type {
   // Function type
   Type *return_ty;
   Type *params;
+  bool is_variadic;
   Type *next;
 };
 
diff --git a/parse.c b/parse.c
index 5ee3228..6d87145 100644
--- a/parse.c
+++ b/parse.c
@@ -485,7 +485,7 @@ static Type *typespec(Token **rest, Token *tok, VarAttr *attr) {
   return ty;
 }
 
-// func-params = ("void" | param ("," param)*?)? ")"
+// func-params = ("void" | param ("," param)* ("," "...")?)? ")"
 // param       = typespec declarator
 static Type *func_params(Token **rest, Token *tok, Type *ty) {
   if (equal(tok, "void") && equal(tok->next, ")")) {
@@ -495,11 +495,19 @@ static Type *func_params(Token **rest, Token *tok, Type *ty) {
 
   Type head = {};
   Type *cur = &head;
+  bool is_variadic = false;
 
   while (!equal(tok, ")")) {
     if (cur != &head)
       tok = skip(tok, ",");
 
+    if (equal(tok, "...")) {
+      is_variadic = true;
+      tok = tok->next;
+      skip(tok, ")");
+      break;
+    }
+
     Type *ty2 = typespec(&tok, tok, NULL);
     ty2 = declarator(&tok, tok, ty2);
 
@@ -516,6 +524,7 @@ static Type *func_params(Token **rest, Token *tok, Type *ty) {
 
   ty = func_type(ty);
   ty->params = head.next;
+  ty->is_variadic = is_variadic;
   *rest = tok->next;
   return ty;
 }
diff --git a/test/common b/test/common
index d488bdd..74065f7 100644
--- a/test/common
+++ b/test/common
@@ -22,3 +22,13 @@ int false_fn() { return 512; }
 int true_fn() { return 513; }
 int char_fn() { return (2<<8)+3; }
 int short_fn() { return (2<<16)+5; }
+
+int add_all(int n, ...) {
+  va_list ap;
+  va_start(ap, n);
+
+  int sum = 0;
+  for (int i = 0; i < n; i++)
+    sum += va_arg(ap, int);
+  return sum;
+}
diff --git a/test/function.c b/test/function.c
index df09ddd..0c0d36d 100644
--- a/test/function.c
+++ b/test/function.c
@@ -70,6 +70,8 @@ _Bool false_fn();
 char char_fn();
 short short_fn();
 
+int add_all(int n, ...);
+
 int main() {
   ASSERT(3, ret3());
   ASSERT(8, add2(3, 5));
@@ -116,6 +118,11 @@ int main() {
   ASSERT(3, char_fn());
   ASSERT(5, short_fn());
 
+  ASSERT(6, add_all(3,1,2,3));
+  ASSERT(5, add_all(4,1,2,3,-1));
+
+  ASSERT(0, ({ char buf[100]; sprintf(buf, "%d %d %s", 1, 2, "foo"); strcmp("1 2 foo", buf); }));
+
   printf("OK\n");
   return 0;
 }
diff --git a/test/test.h b/test/test.h
index 380607a..de46a32 100644
--- a/test/test.h
+++ b/test/test.h
@@ -1,7 +1,7 @@
 #define ASSERT(x, y) assert(x, y, #y)
 
 int assert(int expected, int actual, char *code);
-int printf();
-int sprintf();
+int printf(char *fmt, ...);
+int sprintf(char *buf, char *fmt, ...);
 int strcmp(char *p, char *q);
 int memcmp(char *p, char *q, long n);
diff --git a/tokenize.c b/tokenize.c
index 577b760..373eb1e 100644
--- a/tokenize.c
+++ b/tokenize.c
@@ -333,7 +333,8 @@ static Token *tokenize(char *filename, char *p) {
     }
 
     // Three-letter punctuators
-    if (startswith(p, "<<=") || startswith(p, ">>=")) {
+    if (startswith(p, "<<=") || startswith(p, ">>=") ||
+        startswith(p, "...")) {
       cur = new_token(TK_RESERVED, cur, p, 3);
       p += 3;
       continue;
-- 
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