Re: RFC: Should -fplugin and -fplugin-arg options be excluded from DW_AT_producer recording?

On Wed, Aug 12, 2026 at 12:40 PM Jaihind Yadav
<[email protected]> wrote:
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> Hi,
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>
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> While investigating a build-path leakage issue, I noticed that
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> -fplugin=<path> and -fplugin-arg-* options are currently recorded in
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> DW_AT_producer when -grecord-gcc-switches is enabled.
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>
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> As a result, an absolute plugin path may become embedded in debug
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> metadata.
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>
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> For example:
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>
>
> gcc -g -grecord-gcc-switches \
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> -fplugin=/path/to/plugin.so \
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> -c hello.c
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>
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> produces an object file whose DW_AT_producer contains:
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>
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> GNU C23 ... -g -fplugin=/path/to/plugin.so
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>
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> In my case, the recorded path was an absolute build-system path to a
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> GCC plugin:
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> -fplugin=/local/.../scripts/gcc-plugins/stackleak_plugin.so
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>
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> This introduces host-specific path information into the generated
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> artifact and may negatively affect reproducibility.
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>
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> I noticed that GCC already has the NoDWARFRecord mechanism for options
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> that should not be recorded in the producer string. Looking through the
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> history, it appears that this mechanism was introduced partly to address
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> reproducibility concerns involving path-containing options, and there
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> are also examples where specific options are intentionally excluded from
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> producer-string recording.
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>
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> As an experiment, I modified:
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> gcc/common.opt
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>
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> and marked:
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> -fplugin=
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> -fplugin-arg-*
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>
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> with NoDWARFRecord.
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>
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> With this change:
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>
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> Before:
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> DW_AT_producer:
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> GNU C23 ... -g \
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> -fplugin=/local/.../stackleak_plugin.so
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>
>
> After:
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> DW_AT_producer:
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> GNU C23 ... -g
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>
>
> The plugin is still loaded correctly, plugin arguments are still passed,
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> and generated code/debug information remain unchanged. The only observed
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> difference is that plugin-related command-line options are no longer
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> recorded in DW_AT_producer.
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>
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> The tradeoff appears to be:
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>
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> Benefits:
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> - Avoids recording host-specific absolute plugin paths.
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> - Improves reproducibility of producer strings.
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> - Reduces leakage of local build environment details.
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>
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> Downsides:
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> - Reduces provenance information available from DW_AT_producer.
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> - Makes it harder to determine from the binary alone which GCC plugin
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> (and plugin arguments) were used during compilation.
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>
>
> Before preparing a formal patch submission, I would like feedback on the
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> policy aspect:
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>
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> Should -fplugin and -fplugin-arg-* be treated similarly to other
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> path-sensitive options and be excluded from producer-string
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> recording?

No, they should not be excluded as they are clearly affecting
the compilation.  Is there not a standard plugin search path
so the build systems can use -fplugin=<name>.so without path?

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>
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> or
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> Is preserving plugin provenance in DW_AT_producer considered more
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> valuable than avoiding path leakage and reproducibility issues?
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>
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> Comments and guidance would be appreciated.
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>
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> Thanks,
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> Jaihind Yadav
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>