[LLVMdev] [patch] New feature: debug info for function memory ranges (-jit-emit-debug-function-range)

[Reid Kleckner]

On Sat, Jun 19, 2010 at 5:30 PM, Yuri <yuri at rawbw.com> wrote:
> On 06/19/2010 14:14, Jeffrey Yasskin wrote:
>> Have you found http://llvm.org/docs/DebuggingJITedCode.html? The JIT
>> already has support for something like this for gdb's benefit
>
> Yes, I saw it and tried it. -jit-emit-debug generates ELF image in
> memory with debug info.
> Another option -jit-emit-debug-to-disk creates .o ELF files with debug
> info, one per function. If there are thousands of functions there will
> be thousands of files.
>
> perftools can't use the first option, since it only collects stack
> address information during the run. And it would be very
> difficult/impractical to list all (thousands) of the resulting .o files
> into pprof's command line. Same with valgrind and very slow to load them
> since pprof runs addr2line per object file. This will take forever.
>
> So option -jit-emit-debug-function-range is meant to amend the above
> two. It creates just one file with information just sufficient for
> perftools.

Sounds good.  It's probably overkill, but it would be nice if
perftools could be made to Just Work with the JIT debugging interface.

Reid