On Tue, Jan 14, 2020 at 12:36:11PM +0100, Martin Liška wrote:
> The missing sanitizer reports about violations of function signatures
> for indirect calls, like:
>
> $ cat sanitize-function.cpp
> #include <inttypes.h>
>
> void f() {}
> void (*fnpointer) (int);
>
> void save () {
> fnpointer = reinterpret_cast<void (*)(int)>(reinterpret_cast<uintptr_t>(f));
> }
>
> int main(void) {
> save ();
> fnpointer (32);
> }
_Z4savev: # @_Z4savev
.cfi_startproc
.long 846595819 # 0x327606eb
.long .L__unnamed_2-_Z4savev
# %bb.0: # %entry
...
seems to be what they emit on x86_64. Now, wonder what they do on other
targets, and how does it play with all the other options that add stuff
to the start of functions, e.g. -fcf-protection=full (where it needs to
really start with endbr64 instruction), or the various options for
patcheable function entries, -mfentry, profiling and the like.
Jakub
