I also wonder if you have something like LTO enabled.
No, he doesn't enable LLVM LTO. Even if it did, LTO wouldn't touch
the 'CC1000SendReceiveP*' definitions because they are not static
(unless he explicitly built with an export map).
Interesting.
I haven't analyzed what is going on in this example though. The
code is probably using some undefined behavior and getting zapped.
This access is being eliminated:
_cil_inline_tmp_23 =
((unsigned int)
*((uint8_t const *) ((void const *) ((unsigned char *) 0U)) +
1) << 8) | (unsigned int) *((uint8_t const *) ((void const *)
GCC generates
movzbl 1, %eax
movzbl 0, %edx
sall $8, %eax
orl %edx, %eax
ret
so probably LLVM is eliminating NULL pointer accesses, or something like
that. This is the undefined behavior.
Thanks for following up.
Paolo
