[LLVMdev] [LLVM, llvm-diff] Question about FunctionDifferenceEngine and DiffConsumer::printValue

Stepan Dyatkovskiy stpworld at narod.ru
Mon Oct 31 02:29:42 PDT 2011


Hi,

Please find the attached patch for review.

-Stepan.

John McCall wrote:
> On Oct 28, 2011, at 2:00 AM, Stepan Dyatkovskiy wrote:
>> I found next code when switch instruction differs:
>>
>> Engine.logf("right switch has extra case %r")<<  CaseValue;
>>
>> Where CaseValue is a ConstantInt object. Looking how logf works I found
>> that it invokes DiffConsumer::printValue method for CaseValue. And here
>> I found that CaseValue itself will never printed. On first look how
>> DiffConsumer::printValue works it seems that for all constants "object
>> numbering" should be printed:
>>
>> out<<  '%'<<  ctxt.RNumbering[V]; // V = CaseValue in our case.
>>                                    // RNumbering is instance of
>> DenseMap<Value*,unsigned>.
>>
>> Then I look into DiffConsumer.cpp, ComputeNumbering method that fills
>> RNumbering and LNumbering. Well, numbering computed for function
>> arguments, basic blocks and instructions only.
>>
>> It means that for Constants "%0" will be printed always. If so, I
>> propose to add case for constants in DiffConsumer::printValue method,
>> that will print constant itself.
>
> Patches welcome!
>
> John.

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