Rust: Tracking issue for `-Z strip=val` option

[petrochenkov]

Option -Z strip=val controls stripping of debuginfo and similar auxiliary data from binaries
during linking.

Supported values for this option are:

• none - debuginfo and symbols (if they exist) are copied to the produced binary or separate files
  depending on the target (e.g. .pdb files in case of MSVC).
• debuginfo - debuginfo sections and debuginfo symbols from the symbol table section
  are stripped at link time and are not copied to the produced binary or separate files.
• symbols - same as debuginfo, but the rest of the symbol table section is stripped as well
  if the linker supports it.

---

History:

• The option was introduced in https://github.com/rust-lang/rust/pull/71825.
• Documentation is added in https://github.com/rust-lang/rust/pull/72111.

[ccope]

Is there a way to make the compiler emit separate debug symbol files (besides the default on Windows)?

[ehuss]

@ccope I think split debug support on Linux is tracked in #34651.

[ehuss]

This flag doesn't seem to work with the Darwin linker (ld64). MacOS is defined to use the gcc linker flavor, but although it uses clang, the underlying ld64 doesn't support gcc options.

Is there an intent to support that?

[petrochenkov]

src\librustc_codegen_ssa\back\linker.rs has a bunch of special cases for the MacOS linker, but it's still considered a GccLinker linker flavor.
Perhaps it needs one more such case for symbol stripping.

That's pretty much all I know about MacOS linker and MacOS in general, so no plans to fix it from me.

[eggyal]

MacOS linker supports -s and -S shorthand arguments, but not --strip-all and --strip-debug longhand arguments; given that the shorthands are supported by all GCC linkers (afaik), perhaps one only needs to change GccLinker::debuginfo() to use those instead?

[eggyal]

It turns out that, whilst the MacOS linker accepts the -s and -S shorthand arguments, they are obsolete and ignored (they generate warnings rather than the fatal errors produced with the longhand arguments).

The MacOS linker no longer provides any ability to strip its output. Instead, Apple provide a strip utility that can be run on a resulting binary—but caveat that it is designed for the output from Apple compilers and may not work with the layouts produced by other compilers. I've not had any issues using it with rust binaries, however.

[AlexApps99]

This option needs to accept true and false, where true would be the equivalent of symbols and false to none.
Currently both lto and debug also support configuration using true for the highest level, and false for disabled.

Including this option would make a lot of sense and simplify usage of it (but would not remove the old functionality either)