From 936a8232df56cf6fbf41beb3b2329a99498d2167 Mon Sep 17 00:00:00 2001 From: Nicholas Nethercote Date: Tue, 25 Feb 2025 15:25:54 +1100 Subject: Change signature of `target_features_cfg`. Currently it is called twice, once with `allow_unstable` set to true and once with it set to false. This results in some duplicated work. Most notably, for the LLVM backend, `LLVMRustHasFeature` is called twice for every feature, and it's moderately slow. For very short running compilations on platforms with many features (e.g. a `check` build of hello-world on x86) this is a significant fraction of runtime. This commit changes `target_features_cfg` so it is only called once, and it now returns a pair of feature sets. This halves the number of `LLVMRustHasFeature` calls. --- compiler/rustc_codegen_llvm/src/lib.rs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'compiler/rustc_codegen_llvm/src/lib.rs') diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs index 8f72307eeba..833c8441196 100644 --- a/compiler/rustc_codegen_llvm/src/lib.rs +++ b/compiler/rustc_codegen_llvm/src/lib.rs @@ -338,8 +338,8 @@ impl CodegenBackend for LlvmCodegenBackend { llvm_util::print_version(); } - fn target_features_cfg(&self, sess: &Session, allow_unstable: bool) -> Vec { - target_features_cfg(sess, allow_unstable) + fn target_features_cfg(&self, sess: &Session) -> (Vec, Vec) { + target_features_cfg(sess) } fn codegen_crate<'tcx>( -- cgit 1.4.1-3-g733a5