Add rlib digest to identify Rust object files#154861
Add rlib digest to identify Rust object files#154861mehdiakiki wants to merge 1 commit intorust-lang:mainfrom
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This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed. Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers. |
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Got too much on my plate already. @rustbot reroll |
| create_wrapper_file(sess, rlib_digest::SECTION.to_string(), &digest_data); | ||
| let digest_file = emit_wrapper_file(sess, &wrapper, tmpdir.as_ref(), rlib_digest::FILENAME); | ||
| ab.add_file(&digest_file); | ||
| } |
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Can this be added right after the crate metadata instead? That saves time iterating over the rlib at staticlib build time.
| pub(crate) fn read(rlib_path: &Path) -> Option<RlibDigest> { | ||
| let file = File::open(rlib_path).ok()?; | ||
| let mmap = unsafe { Mmap::map(file).ok()? }; | ||
| let archive = ArchiveFile::parse(&*mmap).ok()?; |
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Ideally this mmap would be combined with the one in add_archive.
| if lto { | ||
| let is_rust_object = match &digest { | ||
| Some(d) => d.rust_object_files.iter().any(|f| f == fname), | ||
| None => looks_like_rust_object_file(fname), |
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Why is this fallback necessary? Wouldn't all rlibs contain the digest?
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| pub(crate) const FILENAME: &str = "lib.rlib-digest"; | ||
| pub(crate) const SECTION: &str = ".rlib-digest"; | ||
| const VERSION: u8 = 1; |
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This version is not necessary. By the time the linker code is reached, we already know that the rustc version as embedded in the crate metadata matches exactly.
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This adds a metadata entry to
rlibarchives that lists which members are Rust object files instead of relying on the filename heuristic inlooks_like_rust_object.file. I also added a fallback to the old behavior forrlibsbuilt by older compilers.