Quote version script symbols

[syrel]

Hi

rustc generates an LD version script in the following format:

{
  global:
    exported_symbol;
    some$foo::bar$thing/path.rs:42;

  local:
    *;
};

However, the symbols are not quoted, which means that the following code will cause a linker failure because the gnerated LD version script has an invalid syntax.

#[unsafe(export_name = "some$foo::bar$thing/path.rs:42")]
pub extern "C" fn exported_symbol_with_version_script_special_characters() {}

error: linking with `cc` failed: exit status: 1
  |
  = note:  "cc" "-Wl,--version-script=/project/target/release/deps/rustcYQww7z/list" "-Wl,--no-undefined-version" "/project/target/release/deps/rustcYQww7z/symbols.o" ...
  = note: /project/target/release/deps/rustcYQww7z/list:349: ignoring invalid character `/' in script
          /usr/bin/ld:/project/target/release/deps/rustcYQww7z/list:349: syntax error in VERSION script
          clang: error: linker command failed with exit code 1 (use -v to see invocation)

Special characters such as $, /, ., and : are valid for a symbol name in an ELF binary. LD Script Format documentation specifies (same rules apply for symbols and file names):

If the file name contains a character such as a comma which would otherwise serve to separate file names, you may put the file name in double quotes.

This PR quotes each symbol name before adding it to the global: section. This allows exported symbols containing linker-special characters, such as $, ::, /, ., and :, to be handled correctly by the linker:

{
  global:
    "exported_symbol";
    "some$foo::bar$thing/path.rs:42";

  local:
    *;
};

The new run-make test builds a cdylib with an export_name containing those characters and verifies that the exact symbol is exported from the produced shared object.

Cheers
Alex

[rustbot]

Thanks for the pull request, and welcome! The Rust Project is excited to review your changes, and you should hear from @TaKO8Ki (or someone else) some time within the next two weeks.

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[bjorn3]

Can you check if this fixes #38238?

[syrel]

Can you check if this fixes #38238?

Thanks for referencing the issue! This PR does indeed fix it. Just a comment about trailing spaces in export_name: even though they will be supported on linux, macos strips whitespaces. It might be wise to extend the docs around export_name and link_name to mention platform specific quirks.

[rust-bors]

☔ The latest upstream changes (presumably #158663) made this pull request unmergeable. Please resolve the merge conflicts by rebasing.