On 14.08.2023 17:34, Andrew Cooper wrote:
> On 14/08/2023 4:21 pm, Jan Beulich wrote:
>> Question therefore is whether we can find a way of effecting the needed
>> overrides (including for compiler generated calls) without resorting to
>> emitting .equ (or alike), and hence without doing it fully behind the
>> compiler's back.
>
> --wrap= each symbol, except when compiling wrappers.c ?
>
> This seems to be the normal way to mock out functions including malloc()
> and friends.
What is --wrap= ?
I was thinking along the lines of
void*memcpy(void*, const void*, size_t) __asm__("emul_memcpy");
void*memset(void*, int, size_t) __asm__("emul_memset");
This looks to work at least for explicit __builtin_mem*() invocations,
without LTO. Inspecting the LTO object, though, doesn't show any sign
of "memcpy" in any of the strings it embeds (custom functions are
recorded with strings one can recognize), so I fear this wouldn't work
there either. (But if indeed so, I'd wonder if this wasn't a compiler
bug, as then we don't do things behind the compiler's back anymore.)
Jan
