When `-fstack-clash-protection` is enabled and stack has to be realigned, some parts of redzone is written prior the probe, so probe might overwrite content already written in redzone. To avoid it, we have to make sure the first probe is at full probe size or is the last probe so that we can skip redzone.
It also fixes violation of ABI under PPC where `r1` isn't updated atomically.
This fixes https://bugs.llvm.org/show_bug.cgi?id=49903.
Reviewed By: jsji
Differential Revision: https://reviews.llvm.org/D100290
On subtargets that have a red zone, we will copy the stack pointer to the base
pointer in the prologue prior to updating the stack pointer. There are no other
updates to the base pointer after that. This suggests that we should be able to
restore the stack pointer from the base pointer rather than loading it from the
back chain or adding the frame size back to either the stack pointer or the
frame pointer.
This came about because functions that call setjmp need to restore the SP from
the FP because the back chain might have been clobbered
(see https://reviews.llvm.org/D92906). However, if the stack is realigned, the
restored SP might be incorrect (which is what caused the failures in the two
ASan test cases).
This patch was tested quite extensivelly both with sanitizer runtimes and
general code.
Differential revision: https://reviews.llvm.org/D93327
During reviewing https://reviews.llvm.org/D84419, @efriedma mentioned the gap between realigned stack pointer and origin stack pointer should be probed too whatever the alignment is. This patch fixes the issue for PPC64.
Reviewed By: jsji
Differential Revision: https://reviews.llvm.org/D88078
This patch is part of supporting `-fstack-clash-protection`. Implemented
probing when emitting prologue.
Differential Revision: https://reviews.llvm.org/D81460
Kai Luo