[llvm-commits] [PATCH] Adding x32 ABI triple and separate StackSlotSize in MCAsmInfo

Evan Cheng evan.cheng at apple.com
Fri Jan 18 13:56:31 PST 2013


Hi Eli,

What does "stack slot size" mean? Stack slots may not have the same size, depending on what objects are stored in them.

Evan

On Jan 18, 2013, at 9:00 AM, Eli Bendersky <eliben at google.com> wrote:

> Hello,
> 
> Following David's email on llvmdev
> (http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-January/058209.html),
> here is an initial patch for adding the x32 ABI triple to LLVM.
> 
> The patch is deliberately very simple. All it does is add the new
> Triple::EnvironmentType value for the x32 ABI, and uses it on one
> place - separating stack slot size and pointer size in MCAsmInfo. All
> targets provide the same value there, but x86-64 has to behave
> differently based on the ABI.
> One place where this is important is the data alignment factor in
> DWARF frame section. I discussed this with Rafael previosuly and we
> agreed this solution makes sense.
> 
> A limitation in our llvm-dwarfdump tool currently precludes me from
> adding more tests that direct the slot size. I will try to see if I
> can patch up llvm-dwarfdump to allow this separately. Once that
> capability is in place, I will add more tests.
> 
> Note that changes based on the x32 ABI will have to eventually
> propagate into other places, but I will break it to small reviewable
> and testable chunks over time. For the full picture of where this is
> going, you can refer to the patches Michael Liao sent last year
> (http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-June/050360.html and
> other threads).
> 
> Eli
> <x32-triple-asminfo-slotsize.1.patch>_______________________________________________
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