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machinst ABI: Allow back-end to define stack alignment#2345

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cfallin merged 1 commit intobytecodealliance:mainfrom
uweigand:abi-stackalign
Nov 3, 2020
Merged

machinst ABI: Allow back-end to define stack alignment#2345
cfallin merged 1 commit intobytecodealliance:mainfrom
uweigand:abi-stackalign

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@uweigand uweigand commented Nov 2, 2020

The common gen_prologue code currently assumes that the stack
pointer has to be aligned to twice the word size. While this
is true for many ABIs, it does not hold universally.

This patch adds a new constant STACK_ALIGN that back-ends can
provide to define the specific stack alignment required by the
ABI on that platform.

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uweigand commented Nov 2, 2020

@cfallin This is one of the changes discussed here #2128 (comment) (required for the IBM Z back-end).

@github-actions github-actions bot added cranelift Issues related to the Cranelift code generator cranelift:area:machinst Issues related to instruction selection and the new MachInst backend. cranelift:area:aarch64 Issues related to AArch64 backend. cranelift:area:x64 Issues related to x64 codegen labels Nov 2, 2020
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Thanks!

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cfallin commented Nov 2, 2020

There's some weirdness with wiggle in the x64-backend CI -- looking into it.

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cfallin commented Nov 2, 2020

@uweigand I think #2352 should fix the CI failure; would you mind rebasing to pull that in?

The common gen_prologue code currently assumes that the stack
pointer has to be aligned to twice the word size.  While this
is true for many ABIs, it does not hold universally.

This patch adds a new callback stack_align that back-ends can
provide to define the specific stack alignment required by the
ABI on that platform.
@cfallin cfallin merged commit 5ab7b4a into bytecodealliance:main Nov 3, 2020
@uweigand uweigand deleted the abi-stackalign branch November 10, 2020 12:14
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cranelift:area:aarch64 Issues related to AArch64 backend. cranelift:area:machinst Issues related to instruction selection and the new MachInst backend. cranelift:area:x64 Issues related to x64 codegen cranelift Issues related to the Cranelift code generator

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