在 2019/9/5 7:12, Jacek Caban 写道: > > I'm fine with this patch, but not so much about the fortify patch. > Earlier this year we discussed inlines and if I remember right (sorry, I > can't fine it now, maybe it was on IRC), the conclusion was to try to > move toward static inline everywhere. Commit > 6988d73a95fbbd97a0bdbb517008cf18f4eb5f02 was a test to see if anything > breaks. It seems fine so far, so I'd suggest to open code static inline > for fortify wrappers instead of introducing a few new inline override > macros. > > There is something worse: As these wrappers uses `__builtin_va_arg_pack()` they MUST always be emitted inline, not just be declared inline. If inline is not possible, the inline definition cannot be used, which is exactly the `__gnu_inline__` behavior.
Yeah, the bad news is that we now have a bug:
```
#define __USE_MINGW_ANSI_STDIO 1
#include <stdio.h>
int main(void)
{
printf("%lld\n", (long long)sprintf);
}
```
```
E:\Desktop>gcc test.c
In file included from test.c:2:
C:/MinGW/MSYS2/mingw64/x86_64-w64-mingw32/include/stdio.h: In function
'sprintf':
C:/MinGW/MSYS2/mingw64/x86_64-w64-mingw32/include/stdio.h:371:10: error:
invalid use of '__builtin_va_arg_pack ()'
371 | return __mingw_sprintf( __stream, __format,
__builtin_va_arg_pack() );
|
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
This doesn't happen if `__USE_MINGW_ANSI_STDIO` was not defined, where
the other definition would be used, which is specified as
`__mingw_bos_extern_ovr` rather than `__mingw_va_arg_pack_ovr`. The
former expands to `extern __inline__ __attribute__((__gnu_inline__))`
while the latter expands to `static __inline__`. When the address of the
function is taken, GCC has to emit a body of the latter, which contains
`__builtin_va_arg_pack()`, which causes an error. `snprintf()` always
suffers from this issue because both definitions are specified as
`__mingw_va_arg_pack_ovr`.
I think that `__mingw_va_arg_pack_ovr` should be changed to `extern
__inline__`. It is identical to `__mingw_bos_extern_ovr` thereafter.
--
Best regards,
LH_Mouse
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