AArch64 accesses MachineFrameInfo::getMaxCallFrameSize() before it is computed

[MatzeB]

Bugzilla Link	32867
Version	4.0
OS	All
CC	@TNorthover

Extended Description

https://reviews.llvm.org/D32570 is adding infrastructure to detect whether
MachineFrameInfo::MaxCallFrameSize is queried before it is computed. This fails the following aarch64 tests blocking the assert in the patch to be enabled:

LLVM :: CodeGen/AArch64/arm64-tls-darwin.ll
LLVM :: CodeGen/AArch64/cxx-tlscc.ll

[llvmbot]

I investigated this a little bit, the problem seems to be the ShrinkWrapping calls TFI->determineCalleeSaves() before PEI. The AArch64 implementation of determineCalleeSaves() assumes it is being run after MaxCallFrameSize has been computed by PEI, since it calls MFI::estimateStackSize() which can call getMaxCallFrameSize(), but in this case MaxCallFrameSize has not been computed yet.

[llvmbot]

I should add that the conditions under which this occurs are functions that ShrinkWrapping is considering where MFI->adjustsStack() and TFI->hasReservedCallFrame() are true, which is only true for AArch64 if there are variable sized objects in the frame.

[xgupta]

This fails the following aarch64 tests blocking the assert in the patch to be enabled:

LLVM :: CodeGen/AArch64/arm64-tls-darwin.ll
LLVM :: CodeGen/AArch64/cxx-tlscc.ll

Just check after enabling assert, those two test cases are passing now.
We may close this issue.

[c-rhodes]

Lots of tests for other targets are still failing with the assert enabled, but can also confirm these tests are no longer failing. Closing this one.