[LLVMdev] Any way get debug output of generated assembly from MCJIT without completely redoing CodeGen?

[Eric Christopher]

Yeah, that's probably how I'd do it.

Might be useful if you guys want to contribute that as a command line
option Kevin.

-eric

On Tue, Jun 24, 2014 at 3:03 PM, Kevin Modzelewski <kmod at dropbox.com> wrote:
> We do this in Pyston using a JITEventListener that just disassembles the
> output; it's "it works let's move on"-quality:
> https://github.com/dropbox/pyston/blob/master/src/codegen/dis.cpp
>
> I'm not sure how efficient the disassembling is, but at least the process is
> pretty self-contained.
>
>
> On Tue, Jun 24, 2014 at 1:33 PM, Craig Smith <craig at ni.com> wrote:
>>
>>
>> Hello all,
>>
>> I'm trying to hack MCJIT::emitObject to optionally output the
>> corresponding text assembly associated with the object code being emitted
>> (if a debug flag is set in the app/dev environment which is hosting LLVM).
>> I attempted to do this by adding another AsmPrinter pass to the
>> PassManager, but this runs into all sorts of problems because there's only
>> once MCContext and one MachneModuleInfo pass maintaining various state
>> information (MCSections, MCSymbols, etc.) and the two AsmPrinter passes
>> interfere with each other.
>>
>> The only way I've been able to get this to work is to create an entirely
>> separate PassManager, and use addPassesToEmitFile() on it, which will redo
>> the entire CodeGen process again unnecessarily.
>> Does anyone have any ideas/pointers on how I might do this efficiently?
>> This is only for a debugging aid, but I'd like to not have to compile
>> everything twice when it's enabled.
>>
>> Thanks
>> Craig
>>
>>
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