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

[Kevin Modzelewski]

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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