Add a `--verbose` option for `llvm-strip`

[fxmarty-amd]

Hi, it appears llvm-strip has no --verbose option https://llvm.org/docs/CommandGuide/llvm-strip.html.

strip utility has it and it proves handy. It would be nice to have a verbose option for llvm-strip to see which sections/symbols are removed. In my case, trying to use llvm-objdump --syms or llvm-objdump -TC I am unable to see a difference although the file size is reduced.

Thank you!

[llvmbot]

@llvm/issue-subscribers-tools-llvm-objcopy-strip

Author: None (fxmarty-amd)

Hi, it appears `llvm-strip` has no `--verbose` option https://llvm.org/docs/CommandGuide/llvm-strip.html.

strip utility has it and it proves handy. It would be nice to have a verbose option for llvm-strip to see which sections/symbols are removed. In my case, trying to use llvm-objdump --syms or llvm-objdump -TC I am unable to see a difference although the file size is reduced.

Thank you!

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. Check that no other contributor has already been assigned to this issue. If you believe that no one is actually working on it despite an assignment, ping the person. After one week without a response, the assignee may be changed.
2. In the comments of this issue, request for it to be assigned to you, or just create a pull request after following the steps below. Mention this issue in the description of the pull request.
3. Fix the issue locally.
4. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
5. Create a Git commit.
6. Run git clang-format HEAD~1 to format your changes.
7. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation. Mention this issue in the description of the pull request.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: None (fxmarty-amd)

Hi, it appears `llvm-strip` has no `--verbose` option https://llvm.org/docs/CommandGuide/llvm-strip.html.

strip utility has it and it proves handy. It would be nice to have a verbose option for llvm-strip to see which sections/symbols are removed. In my case, trying to use llvm-objdump --syms or llvm-objdump -TC I am unable to see a difference although the file size is reduced.

Thank you!

[jh7370]

I think this seems very reasonable to add. I also don't think it'd be especially complicated, so I've added the "good-first-issue" label.

To whomever picks this up: note that llvm-objcopy and llvm-strip share the same codebase and it seems reasonable for them both to gain this option. Please also make sure the output looks similar to the GNU version.

@fxmarty-amd, if you fancy tackling this yourself, by all means do so. With regards to identifying why your size changed, two comments:

1. Try using llvm-readelf --all to dump everything. This will either directly (missing sections/symbols/etc) or indirectly (adjusted file offsets etc) show the issue.
2. Keep in mind that even if llvm-strip does not remove anything, the object file is still potentially rebuilt, i.e. gaps in the file might be removed, depending on the alignment constraints of the sections in the file.

[kshitijvp]

I want to work. Can you assign it to me? Thanks!

[jh7370]

@fxmarty-amd, were you planning on implementing this yourself, or are you happy for @kshitijvp to do so? I've assigned it to @kshitijvp for now, but would like @fxmarty-amd to confirm they're not planning on tackling it themselves first, as if they'd like to, it'd make sense for them to do so, since they opened the issue in the first place.

[fxmarty-amd]

Thank you! For sure @kshitijvp, feel free to give it a go!