llvm dev - May 2014 - [LLVMdev] Associate IR instruction with corresponding assembly

Hi,

Is there a way to associate LLVM IR instructions with the instructions they
finally generate in the assembly file emitted by LLC? I need to track the
PC's corresponding to certain IR level instructions for ARM.
One way to do this is to tag an IR instruction with a special flag and pass
that flag onto the Machine IR created by LLC and then onto Machine Code. It
would be helpful if I could get some pointers on how to do this.

Thanks in advance,

Shruti Padmanabha
University of Michigan, Ann Arbor
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On 17/05/2014 23:05, shruti padmanabha wrote:
> Hi,
>
> Is there a way to associate LLVM IR instructions with the instructions they
> finally generate in the assembly file emitted by LLC? I need to track the
> PC's corresponding to certain IR level instructions for ARM.
> One way to do this is to tag an IR instruction with a special flag and pass
> that flag onto the Machine IR created by LLC and then onto Machine Code. It
> would be helpful if I could get some pointers on how to do this.
You may want to look at the -debug-ir pass, which creates METADATA to 
emit debugging information that allows you to associate machine 
instructions with IR instructions. This may or may not be what you want.

Tobias

Hi,

Thanks for the pointer. I am unfortunately running into llc problems with
this pass.
I did
*opt  -debug-ir   hello.bc -o hello.deb.bc*

*llc -march=arm -debug  -O0 hello.deb.bc  -o hello.deb.s*

This is aborting with the error: llc:
llvm-3.4/lib/CodeGen/AsmPrinter/DwarfDebug.cpp:1614: void
llvm::DwarfDebug::beginFunction(const llvm::MachineFunction*): Assertion
`TheCU && "Unable to find compile unit!"' failed.
I'm assuming this is because llc found some errors in the metadata that
debug-ir prints out. How do I find and correct this?

Thanks again,
Shruti




On Sat, May 17, 2014 at 5:57 PM, Tobias Grosser <tobias at grosser.es>
wrote:
> On 17/05/2014 23:05, shruti padmanabha wrote:
>
>> Hi,
>>
>> Is there a way to associate LLVM IR instructions with the instructions
>> they
>> finally generate in the assembly file emitted by LLC? I need to track
the
>> PC's corresponding to certain IR level instructions for ARM.
>> One way to do this is to tag an IR instruction with a special flag and
>> pass
>> that flag onto the Machine IR created by LLC and then onto Machine
Code.
>> It
>> would be helpful if I could get some pointers on how to do this.
>>
>
> You may want to look at the -debug-ir pass, which creates METADATA to emit
> debugging information that allows you to associate machine instructions
> with IR instructions. This may or may not be what you want.
>
> Tobias
>


-- 
Shruti Padmanabha
University of Michigan, Ann Arbor
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