clang-cl miscompiles calls to swprintf

[zmodem]

Bugzilla Link	21247
Resolution	FIXED
Resolved on	Sep 21, 2015 22:00
Version	trunk
OS	Windows NT
Blocks	#14079 #19261
CC	@majnemer,@rnk,@timurrrr

Extended Description

Consider:

#include <stdio.h>

int main() {
wchar_t buf[1024];

swprintf(buf, 1024, L"hello %d\n", 42);
printf("%ws\n", buf);

return 0;

}

Compiled with clang-cl, the program prints garbage (debug mode) or 0 (optimized).

Note that this happens when we hit the inline definition of swprintf in VC/include/swprinf.inl, which gets included from stdio.h.

[majnemer]

I wouldn't be surprised if this was caused by _crt_va_start/_crt_va_end mapping to something crazy with clang-cl.

[zmodem]

r219740

[nico]

*** Bug #12534 has been marked as a duplicate of this bug. ***