[cfe-dev] Define new pragma in Clang

[Alexandra]

Daniel Dunbar <daniel at ...> writes:

> 
> Hi Alexandra,
> 
> Its hard for me to know the problem without seeing the patch/crash. It
> looks like clang is crashing when it tries to index into a SmallVector
> out-of-bounds. I suggest you run clang in a debugger and see what code
> is doing this, which will probably give a clue as to the problem.
> 
>  - Daniel


It seems that the problem is in the file Metadata.cpp in 
void MetadataContextImpl::
getMDs(const Instruction *Inst, SmallVectorImpl<MDPairTy> &MDs) const {

...

 // MD kinds are numbered from 1.
 MDs[MI->first - 1] = std::make_pair(MI->first, MI->second);

}

Since the instruction has metadata attached, but the value of the MD kind is 2.
The metadata with MD kind equal to 1 was attached to a previous instruction.
Taking care of the index of  MDs[MI->first - 1] solves the problem. 

I used an int idx = 0 and  MDs[idx++] = std::make_pair(MI->first, MI->second);

I hope this is correct.

Alexandra