[llvm] r175317 - c[ms-inline asm] It's possible to have a SizeDirective rewrite and an

[Chad Rosier]

On Feb 15, 2013, at 11:33 PM, Timur Iskhodzhanov <timurrrr at google.com> wrote:

> Do you think you should also add a small repro test for this case?

I don't think it's necessary and would very likely be fragile.  The llvm_unreachable at the end of the sort function should ensure the sort is forever stable/deterministic.

 Chad

> It looked like the assertion didn't fire on the existing set of tests.
> 
> 2013/2/16 Chad Rosier <mcrosier at apple.com>:
>> Author: mcrosier
>> Date: Fri Feb 15 16:54:16 2013
>> New Revision: 175317
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=175317&view=rev
>> Log:
>> c[ms-inline asm] It's possible to have a SizeDirective rewrite and an
>> Input/Output rewrite to the same location.  Make sure the SizeDirective rewrite
>> is performed first.  This also ensure the sort algorithm is stable.
>> 
>> Modified:
>>    llvm/trunk/lib/MC/MCParser/AsmParser.cpp
>> 
>> Modified: llvm/trunk/lib/MC/MCParser/AsmParser.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCParser/AsmParser.cpp?rev=175317&r1=175316&r2=175317&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/MC/MCParser/AsmParser.cpp (original)
>> +++ llvm/trunk/lib/MC/MCParser/AsmParser.cpp Fri Feb 15 16:54:16 2013
>> @@ -4041,7 +4041,21 @@ static int RewritesSort(const void *A, c
>>     return -1;
>>   if (AsmRewriteB->Loc.getPointer() < AsmRewriteA->Loc.getPointer())
>>     return 1;
>> -  return 0;
>> +
>> +  // It's possible to have a SizeDirective rewrite and an Input/Output rewrite
>> +  // to the same location.  Make sure the SizeDirective rewrite is performed
>> +  // first.  This also ensure the sort algorithm is stable.
>> +  if (AsmRewriteA->Kind == AOK_SizeDirective) {
>> +    assert ((AsmRewriteB->Kind == AOK_Input || AsmRewriteB->Kind == AOK_Output) &&
>> +            "Expected an Input/Output rewrite!");
>> +    return -1;
>> +  }
>> +  if (AsmRewriteB->Kind == AOK_SizeDirective) {
>> +    assert ((AsmRewriteA->Kind == AOK_Input || AsmRewriteA->Kind == AOK_Output) &&
>> +            "Expected an Input/Output rewrite!");
>> +    return 1;
>> +  }
>> +  llvm_unreachable ("Unstable rewrite sort.");
>> }
>> 
>> bool
>> @@ -4174,6 +4188,7 @@ AsmParser::ParseMSInlineAsm(void *AsmLoc
>>                                              E = AsmStrRewrites.end();
>>        I != E; ++I) {
>>     const char *Loc = (*I).Loc.getPointer();
>> +    assert(Loc >= Start && "Expected Loc to be after Start!");
>> 
>>     unsigned AdditionalSkip = 0;
>>     AsmRewriteKind Kind = (*I).Kind;
>> 
>> 
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