diff options
Diffstat (limited to 'compiler/rustc_codegen_ssa/src')
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/target_features.rs | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/compiler/rustc_codegen_ssa/src/target_features.rs b/compiler/rustc_codegen_ssa/src/target_features.rs index d984156c674..7e4341a8236 100644 --- a/compiler/rustc_codegen_ssa/src/target_features.rs +++ b/compiler/rustc_codegen_ssa/src/target_features.rs @@ -197,7 +197,10 @@ fn parse_rust_feature_flag<'a>( /// 2nd component of the return value, respectively). /// /// `target_base_has_feature` should check whether the given feature (a Rust feature name!) is -/// enabled in the "base" target machine, i.e., without applying `-Ctarget-feature`. +/// enabled in the "base" target machine, i.e., without applying `-Ctarget-feature`. Note that LLVM +/// may consider features to be implied that we do not and vice-versa. We want `cfg` to be entirely +/// consistent with Rust feature implications, and thus only consult LLVM to expand the target CPU +/// to target features. /// /// We do not have to worry about RUSTC_SPECIFIC_FEATURES here, those are handled elsewhere. pub fn cfg_target_feature( @@ -211,7 +214,15 @@ pub fn cfg_target_feature( .rust_target_features() .iter() .filter(|(feature, _, _)| target_base_has_feature(feature)) - .map(|(feature, _, _)| Symbol::intern(feature)) + .flat_map(|(base_feature, _, _)| { + // Expand the direct base feature into all transitively-implied features. Note that we + // cannot simply use the `implied` field of the tuple since that only contains + // directly-implied features. + // + // Iteration order is irrelevant because we're collecting into an `UnordSet`. + #[allow(rustc::potential_query_instability)] + sess.target.implied_target_features(base_feature).into_iter().map(|f| Symbol::intern(f)) + }) .collect(); // Add enabled and remove disabled features. |