bjoernager/rust
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Add run-make-fulldeps test

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Implement RUSTC_FORCE_INCR_COMP_ARTIFACT_HEADER

Also makes minor docs edits.
This commit is contained in:
pierwill 2021-10-28 12:00:43 -05:00
parent 7d7dfba350
commit 535278aa51
12 changed files with 102 additions and 31 deletions
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19
compiler/rustc_span/src/def_id.rs
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@ -126,14 +126,17 @@ impl Borrow<Fingerprint> for DefPathHash {
}
}
/// A [`StableCrateId`] is a 64 bit hash of the crate name combined with all
/// `-Cmetadata` arguments. It is to [`CrateNum`] what [`DefPathHash`] is to
/// A [`StableCrateId`] is a 64-bit hash of a crate name, together with all
/// `-Cmetadata` arguments, and some other data. It is to [`CrateNum`] what [`DefPathHash`] is to
/// [`DefId`]. It is stable across compilation sessions.
///
/// Since the ID is a hash value there is a (very small) chance that two crates
/// Since the ID is a hash value, there is a small chance that two crates
/// end up with the same [`StableCrateId`]. The compiler will check for such
/// collisions when loading crates and abort compilation in order to avoid
/// further trouble.
///
/// See the discussion in [`DefId`] for more information
/// on the possibility of hash collisions in rustc,
#[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Debug)]
#[derive(HashStable_Generic, Encodable, Decodable)]
pub struct StableCrateId(pub(crate) u64);
@ -174,8 +177,14 @@ impl StableCrateId {
// Also incorporate the rustc version. Otherwise, with -Zsymbol-mangling-version=v0
// and no -Cmetadata, symbols from the same crate compiled with different versions of
// rustc are named the same.
let rustc_version = option_env!("CFG_VERSION").unwrap_or("unknown version").as_bytes();
hasher.write(rustc_version);
//
// RUSTC_FORCE_INCR_COMP_ARTIFACT_HEADER is used to inject rustc version information
// during testing.
if let Some(val) = std::env::var_os("RUSTC_FORCE_INCR_COMP_ARTIFACT_HEADER") {
hasher.write(val.to_string_lossy().into_owned().as_bytes())
} else {
hasher.write(option_env!("CFG_VERSION").unwrap_or("unknown version").as_bytes());
}
StableCrateId(hasher.finish())
}