Hi,
On 31 March 2017 at 14:47, Dibyendu Majumdar <mobile@xxxxxxxxxxxxxxx> wrote:
> I am investigating a failure in this test:
>
> #include <stdarg.h>
> #include <stdlib.h>
> #include <stdio.h>
>
> void error_message(const char *fmt, ...) {
> va_list argp;
> va_start(argp, fmt);
> vfprintf(stdout, fmt, argp);
> va_end(argp);
> }
>
> int main(void)
> {
> error_message("%s\n", "hello world");
> return 0;
> }
>
>
> The linearized output for error_message() is:
>
> rror_message:
> .L0:
> <entry-point>
> store.64 %arg1 -> 0[fmt]
> cast.64 %r2 <- (64) fmt
> load.64 %r3 <- 0[stdout]
> call.32 %r6 <- vfprintf, %r3, %arg1, %r2
> ret
>
> Above seems incorrect to me, as %r2 should be pointing to [8]fmt presumably?
>
I think this might be because the macro __builtin_va_start() is being
defined in sparse but this doesn't match what gets defined by gcc? I
see this in sparse:
#define __builtin_va_start(a,b) ((a) = (__builtin_va_list)(&(b)))
but if I run above code through gcc then preprocessed output says:
__builtin_va_start(argp, fmt);
Thanks and Regards
Dibyendu
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