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Rollup merge of #56609 - michaelwoerister:unconditional-target-cpu-attr, r=alexcrichton

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Unconditionally emit the target-cpu LLVM attribute.

This PR makes `rustc` always emit the `target-cpu` LLVM attribute for functions. The goal is to allow for cross-language inlining of functions defined in `libstd`. So far `libstd` functions were the only function without a `target-cpu` attribute, so in whole-crate-graph cross-lang LTO scenarios they were not eligible for inlining into foreign code.

r? @alexcrichton
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kennytm 2018-12-14 22:10:04 +08:00 committed by GitHub
commit 4f0f1102bf
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1 changed files with 3 additions and 7 deletions
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10
src/librustc_codegen_llvm/attributes.rs
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@ -18,6 +18,7 @@
use rustc::ty::{self, TyCtxt, PolyFnSig};
use rustc::ty::layout::HasTyCtxt;
use rustc::ty::query::Providers;
use rustc_data_structures::small_c_str::SmallCStr;
use rustc_data_structures::sync::Lrc;
use rustc_data_structures::fx::FxHashMap;
use rustc_target::spec::PanicStrategy;
@ -130,8 +131,7 @@ pub fn llvm_target_features(sess: &Session) -> impl Iterator<Item = &str> {
}
pub fn apply_target_cpu_attr(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
let cpu = llvm_util::target_cpu(cx.tcx.sess);
let target_cpu = CString::new(cpu).unwrap();
let target_cpu = SmallCStr::new(llvm_util::target_cpu(cx.tcx.sess));
llvm::AddFunctionAttrStringValue(
llfn,
llvm::AttributePlace::Function,
@ -231,11 +231,7 @@ pub fn from_fn_attrs(
// Always annotate functions with the target-cpu they are compiled for.
// Without this, ThinLTO won't inline Rust functions into Clang generated
// functions (because Clang annotates functions this way too).
// NOTE: For now we just apply this if -Zcross-lang-lto is specified, since
// it introduce a little overhead and isn't really necessary otherwise.
if cx.tcx.sess.opts.debugging_opts.cross_lang_lto.enabled() {
apply_target_cpu_attr(cx, llfn);
}
apply_target_cpu_attr(cx, llfn);
let features = llvm_target_features(cx.tcx.sess)
.map(|s| s.to_string())