[jsc-dev] Idea: DWARF in offlineasm output

[Michael Saboff]

Konstantin,

Provided that gcc & gdb work with Dwarf2 .loc and .file directives and gcc can handle multiple .file directives in one file, it should work with that toolchain.  I just haven’t tested it.

The single line change I added to the processor specific files, e.g. arm.rb, would need to be added to mips.rb and the other processor backend .rb files.  I also didn’t make those since I can’t test them either.

If you could try add the single line change to mips.rb and test on gcc / gdb that would be great.

- Michael

> On Jan 4, 2016, at 11:47 AM, Konstantin Tokarev <annulen at yandex.ru> wrote:
> 
> 
> 
> 04.01.2016, 22:39, "Michael Saboff" <msaboff at apple.com <mailto:msaboff at apple.com>>:
>> Konstantin,
>> 
>> Actually, that change hasn’t been landed.  I have been waiting for a fix in the clang toolchain.  I have provided that fix to the clang team, but it hasn’t landed yet.
>> 
>> I posted my DWARF2 changes to the bug: <https://bugs.webkit.org/show_bug.cgi?id=152703> - “offlineasm: Emit Dwarf2 file and location directives to allow for debugging .asm files”.
>> 
>> I’ll work with the clang team to get that change done.
>> 
>> If you are willing, it would be good to get gcc/gdb working with the change as well.  I only did changes for the compiler (clang) and CPUs (X86, ARM & ARM64) that I could test.
> 
> Michael,
> 
> Problem is that I'm using gcc (and my target is MIPS). Does your change work with GCC, or this is clang-only feature?
> 
> Though I guess it should be feasible to build one assembly file with clang using its MIPS backend, and use gcc for the rest of build.
> 
>> 
>> - Michael
>> 
>>> On Jan 4, 2016, at 10:47 AM, Konstantin Tokarev <annulen at yandex.ru> wrote:
>>> 
>>> 04.01.2016, 21:41, "Geoffrey Garen" <ggaren at apple.com>:
>>>> Michael Saboff recently added file and line number annotations to offlineasm.
>>>> 
>>>> What other kinds of information would you add using DWARF? How would you update the DWARF information when the .asm file changed?
>>> 
>>> I thought it would be useful to have files and line numbers as DWARF instead of comments so it would be easier to single-step with gdb.
>>> 
>>> Also, macros could be annotated as inline functions.
>>> 
>>> However, for now I've fixed crash that I was struggling with.
>>> 
>>>> Geoff
>>>> 
>>>>>  On Jan 3, 2016, at 12:48 PM, Konstantin Tokarev <annulen at yandex.ru> wrote:
>>>>> 
>>>>>  Hi JSC developers,
>>>>> 
>>>>>  Haven't you ever considered adding DWARF information into assembly produced by offlineasm? I'm trying to fix MIPS backend right now, and I thought it may be useful to debug crashes in LLINT.
>>>>> 
>>>>>  --
>>>>>  Regards,
>>>>>  Konstantin
>>>>>  _______________________________________________
>>>>>  jsc-dev mailing list
>>>>>  jsc-dev at lists.webkit.org
>>>>>  https://lists.webkit.org/mailman/listinfo/jsc-dev
>>> 
>>> --
>>> Regards,
>>> Konstantin
>>> _______________________________________________
>>> jsc-dev mailing list
>>> jsc-dev at lists.webkit.org
>>> https://lists.webkit.org/mailman/listinfo/jsc-dev
> 
> 
> -- 
> Regards,
> Konstantin

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