llvm dev - Jun 2020 - How to fixup source paths during objdump disassembly?

Hi folks,

As part of our build, the Tock project uses remap-path-prefix [1] to create
a reproducible build. This means that the paths inside of built artifacts
are not full source paths. When we later attempt to produce a listings
file, the source mapping fails. The result is many copies of this recently
merged warning [2]:

     llvm-objdump: warning:
'/Volumes/code/helena-project/tock/target/thumbv7em-none-eabi/release/hail.elf':
failed to find source chips/sam4l/src/eic.rs

It looks like GNU objdump provides a --prefix option to address this exact
problem [3]:

*    --prefix=**prefix*     Specify *prefix* to add to the absolute paths
when used with *-S*.

But I can't find an equivalent mechanism in llvm-objdump.

What's the correct way to point objdump to source files during disassembly?

To reproduce the problem, `make lst` in any of the boards for the
Tock Operating System (e.g.
https://github.com/tock/tock/tree/master/boards/hail ) will produce many
missing file warnings.

Thanks for your help!

-Pat

[1]
https://doc.rust-lang.org/1.24.0/unstable-book/compiler-flags/remap-path-prefix.html
[2] https://reviews.llvm.org/D62462
[3] https://linux.die.net/man/1/objdump
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As far as I'm aware, there is no equivalent option in llvm-objdump
currently unfortunately. We should add it. Could you file a bug against
llvm-objdump to that effect?

James

On Tue, 16 Jun 2020 at 22:27, Pat Pannuto via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi folks,
>
> As part of our build, the Tock project uses remap-path-prefix [1] to
> create a reproducible build. This means that the paths inside of built
> artifacts are not full source paths. When we later attempt to produce a
> listings file, the source mapping fails. The result is many copies of this
> recently merged warning [2]:
>
>      llvm-objdump: warning:
>
'/Volumes/code/helena-project/tock/target/thumbv7em-none-eabi/release/hail.elf':
> failed to find source chips/sam4l/src/eic.rs
>
> It looks like GNU objdump provides a --prefix option to address this exact
> problem [3]:
>
> *    --prefix=**prefix*     Specify *prefix* to add to the absolute paths
> when used with *-S*.
>
> But I can't find an equivalent mechanism in llvm-objdump.
>
> What's the correct way to point objdump to source files during
disassembly?
>
> To reproduce the problem, `make lst` in any of the boards for the
> Tock Operating System (e.g.
> https://github.com/tock/tock/tree/master/boards/hail ) will produce many
> missing file warnings.
>
> Thanks for your help!
>
> -Pat
>
> [1]
>
https://doc.rust-lang.org/1.24.0/unstable-book/compiler-flags/remap-path-prefix.html
> [2] https://reviews.llvm.org/D62462
> [3] https://linux.die.net/man/1/objdump
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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llvm-symbolizer has --relativenames, which is close. It would only take a
bit of plumbing to add that to llvm-objdump.

On Wed, Jun 17, 2020 at 8:12 AM James Henderson via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> As far as I'm aware, there is no equivalent option in llvm-objdump
> currently unfortunately. We should add it. Could you file a bug against
> llvm-objdump to that effect?
>
> James
>
> On Tue, 16 Jun 2020 at 22:27, Pat Pannuto via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> Hi folks,
>>
>> As part of our build, the Tock project uses remap-path-prefix [1] to
>> create a reproducible build. This means that the paths inside of built
>> artifacts are not full source paths. When we later attempt to produce a
>> listings file, the source mapping fails. The result is many copies of
this
>> recently merged warning [2]:
>>
>>      llvm-objdump: warning:
>>
'/Volumes/code/helena-project/tock/target/thumbv7em-none-eabi/release/hail.elf':
>> failed to find source chips/sam4l/src/eic.rs
>>
>> It looks like GNU objdump provides a --prefix option to address this
>> exact problem [3]:
>>
>> *    --prefix=**prefix*     Specify *prefix* to add to the absolute
>> paths when used with *-S*.
>>
>> But I can't find an equivalent mechanism in llvm-objdump.
>>
>> What's the correct way to point objdump to source files during
>> disassembly?
>>
>> To reproduce the problem, `make lst` in any of the boards for the
>> Tock Operating System (e.g.
>> https://github.com/tock/tock/tree/master/boards/hail ) will produce
many
>> missing file warnings.
>>
>> Thanks for your help!
>>
>> -Pat
>>
>> [1]
>>
https://doc.rust-lang.org/1.24.0/unstable-book/compiler-flags/remap-path-prefix.html
>> [2] https://reviews.llvm.org/D62462
>> [3] https://linux.die.net/man/1/objdump
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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