[PATCH] x86 inline-asm: error-out on a 64-bit variable bound to a single register in 32-bit mode

[Akira Hatanaka]

Rebased patches attached.

I also made changes to the clang patch so that clang can error-out after a
size mismatch is found as soon as
possible.TargetInfo::validateConstraintModifier has an extra parameter
IsError, which is set when it decides there is no point in continuing
compilation and it should stop compilation immediately. The error message
clang prints looks better than lllvm's message, but if it isn't right to
change the warning to an error, then I guess we have to detect the error
later just before isel, as is done in the llvm patch.

On Wed, Jul 23, 2014 at 3:56 PM, Akira Hatanaka <ahatanak at gmail.com> wrote:

> llvm should error-out when a 64-bit variable is bound to a single register
> in x86 32-bit mode, but ToT clang/llvm fails to detect this error and
> continues compilation until it crashes in type-legalization:
>
> $ llc test/CodeGen/X86/inline-asm-regsize.ll  -O3
> -mtriple=i386-apple-darwin -o -
>
> inline-asm-regsize.ll  -O3 -mtriple=i386-apple-darwin -o -
>
> .section __TEXT,__text,regular,pure_instructions
>
> ExpandIntegerResult #0: 0x7fa2d1041728: i64 = Register %RCX [ID=0]
>
>
> Do not know how to expand the result of this operator!
>
> UNREACHABLE executed at
> /Users/ahatanaka/projects/llvm/git/llvm3/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp:1116!
>
> The attached patch fixes llvm to error-out and print this error message:
>
> error: Cannot bind a variable larger than 32-bit to a single register in
> 32-bit mode
>
>
> My initial solution was to have clang detect this error in
> TargetInfo::validateConstraintModifier. However, the code in
> SemaStmtAsm.cpp has to be changed to error-out instead of issuing a
> warning, which I wasn't sure was the right thing to do. I am attaching this
> patch too in case someone has a suggestion or an opinion on it.
>
> <rdar://problem/17476970>
>
>
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