[LLVMdev] Could LLVM or Clang go backward to modify c source code?

[Joshua Warner]

Forgot to CC the list.

On Wed, May 4, 2011 at 10:16 PM, Joshua Warner <joshuawarner32 at gmail.com>wrote:

> Wen-Han,
>
> It sounds like there are two problems here: first is detecting when free is
> not properly called, and figuring out where to insert the call - which seems
> like an intractable problem by iteself.  Second is a reversible translation
> from C to LLVM IR.  LLVM does (did?) have support for generating C code
> again on the back end, but the result doesn't look that much like the
> original code.  In order to translate changes from the IR back to the source
> code, detailed information would have to be kept on what IR structures
> resulted from what source statements and how they interact.  There has been
> work on such reversible transformations done (I can't recall where atm), but
> that was only in very simple cases that could be described by regular
> expressions.
>
> So the short answer is "no."
>
> -Joshua
>
> On Wed, May 4, 2011 at 9:16 PM, Wenhan Gu <nowar100 at gmail.com> wrote:
>
>> Hi all,
>>
>> I have a source code:
>> int* p = malloc(...);
>>
>> After translating to llvm::Module, We can know the source code did not
>> call free.
>> I know we can hack this into Module.
>>
>> But my question is,
>> could we hack it back to source code?
>> After fixing, the source will become:
>> int *p = malloc(...);
>> free(p);
>>
>> Is this feasible?
>>
>> Thanks all very much.
>>
>> --
>> Best regards,
>> Wen-Han
>>
>> _______________________________________________
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>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
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>>
>>
>
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