scc

commit 4626414db8c5ae6f8b65054d74465626be2a4fc1
parent 545b4aacc0f5f08df8c2a75c77ef02287127c098
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Mon, 13 Feb 2017 09:13:10 +0100

[cc1] Add warnings about promotable types in va_arg()

Bool, char  and short are promoted to int when they are passed through ...,
and it means that it is impossible to have them in a stack created by a
variadic function. This patch warns to the user about it and correct
the type to int.

Diffstat:
M
cc1/builtin.c
 | 
6
++++++

1 file changed, 6 insertions(+), 0 deletions(-)
diff --git a/cc1/builtin.c b/cc1/builtin.c
@@ -20,6 +20,12 @@ builtin_va_arg(Symbol *sym)
 		errorp("incorrect parameters for va_arg");
 		return constnode(zero);
 	}
+	if (tp == booltype ||
+	    tp == chartype || tp == uchartype || tp == schartype ||
+	    tp == shortype || tp == ushortype) {
+		warn("bool, char and short are promoted to int when passed through '...'");
+		tp = (tp->prop & TSIGNED) ? inttype : uinttype;
+	}
 
 	np = node(OBUILTIN, tp, ap, NULL);
 	np->sym = sym;