Antonio Abbatangelo b7e110fcfe [X86] Align stack to 16-bytes on 32-bit with X86_INTR call convention ...

Adds a dynamic stack alignment to functions under the interrupt call
convention on x86-32. This fixes the issue where the stack can be
misaligned on entry, since x86-32 makes no guarantees about the stack
pointer position when the interrupt service routine is called.

The alignment is done by overriding X86RegisterInfo::shouldRealignStack,
and by setting the correct alignment in X86FrameLowering::calculateMaxStackAlign.
This forces the interrupt handler to be dynamically aligned, generating
the appropriate `and` instruction in the prologue and `lea` in the
epilogue. The `no-realign-stack` attribute can be used as an opt-out.

Fixes #26851

Reviewed By: pengfei

Differential Revision: https://reviews.llvm.org/D151400

2023-06-01 17:00:34 +08:00

157 KiB

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