This CL handles the caller-side argument padding and out-of-line
scratch/call alignment in the x64 TurboFan / Turboshaft backend:
- InstructionSelector::EmitPrepareArguments: prepend a padding slot at
the highest address when ShouldPadArguments() holds.
- CodeGenerator::AssembleTailCallAfterGap: initialize the optional tail
call padding slot.
- Out-of-line builtin calls add a padding slot when rsp is misaligned
- CodeGenerator::AssembleConstructFrame: pad odd fixed headers around
pre-frame Wasm stack-overflow calls.
No-op unless `v8_x64_16byte_stack_alignment = true`.
TAG=agy
CONV=256fd3be-961f-422c-8d36-eb021c6d03a3
Bug: 42212385
Change-Id: Ia678be3c8522ed8f683015eb86874018e3df2cd2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/8719073
Auto-Submit: Ryan Diaz <ryandiaz@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Ryan Diaz <ryandiaz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#111781}
Ryan Diaz
87b0595e60