Handle function argument type conversion

chibicc.h

@@ -140,6 +140,7 @@ struct Node {
 
   // Function call
   char *funcname;
+  Type *func_ty;
   Node *args;
 
   Obj *var;      // Used if kind == ND_VAR

parse.c

@@ -937,22 +937,35 @@ static Node *funcall(Token **rest, Token *tok) {
   if (!sc->var || sc->var->ty->kind != TY_FUNC)
     error_tok(start, "not a function");
 
-  Type *ty = sc->var->ty->return_ty;
+  Type *ty = sc->var->ty;
+  Type *param_ty = ty->params;
+
   Node head = {};
   Node *cur = &head;
 
   while (!equal(tok, ")")) {
     if (cur != &head)
       tok = skip(tok, ",");
-    cur = cur->next = assign(&tok, tok);
-    add_type(cur);
+
+    Node *arg = assign(&tok, tok);
+    add_type(arg);
+
+    if (param_ty) {
+      if (param_ty->kind == TY_STRUCT || param_ty->kind == TY_UNION)
+        error_tok(arg->tok, "passing struct or union is not supported yet");
+      arg = new_cast(arg, param_ty);
+      param_ty = param_ty->next;
+    }
+
+    cur = cur->next = arg;
   }
 
   *rest = skip(tok, ")");
 
   Node *node = new_node(ND_FUNCALL, start);
   node->funcname = strndup(start->loc, start->len);
-  node->ty = ty;
+  node->func_ty = ty;
+  node->ty = ty->return_ty;
   node->args = head.next;
   return node;
 }

test/function.c

@@ -44,6 +44,10 @@ int g1;
 int *g1_ptr() { return &g1; }
 char int_to_char(int x) { return x; }
 
+int div_long(long a, long b) {
+  return a / b;
+}
+
 int main() {
   ASSERT(3, ret3());
   ASSERT(8, add2(3, 5));
@@ -65,6 +69,8 @@ int main() {
 
   ASSERT(3, *g1_ptr());
   ASSERT(5, int_to_char(261));
+  ASSERT(5, int_to_char(261));
+  ASSERT(-5, div_long(-10, 2));
 
   printf("OK\n");
   return 0;