bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Annotate functions in LLVM with target-cpu, same as Clang does.

Browse source
This commit is contained in:
Michael Woerister 2018-08-02 18:10:26 +02:00
parent f2969ed6c3
commit b27a161939
4 changed files with 50 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

18
src/librustc_codegen_llvm/attributes.rs
View file

@ -123,6 +123,15 @@ pub fn llvm_target_features(sess: &Session) -> impl Iterator<Item = &str> {
.filter(|l| !l.is_empty())
}
pub fn apply_target_cpu_attr(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
let target_cpu = CString::new(cx.tcx.sess.target_cpu().to_string()).unwrap();
llvm::AddFunctionAttrStringValue(
llfn,
llvm::AttributePlace::Function,
cstr("target-cpu\0"),
target_cpu.as_c_str());
}
/// Composite function which sets LLVM attributes for function depending on its AST (#[attribute])
/// attributes.
pub fn from_fn_attrs(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value, id: DefId) {
@ -167,6 +176,15 @@ pub fn from_fn_attrs(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value, id: DefId) {
Some(true) | None => {}
}
// 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);
}
let features = llvm_target_features(cx.tcx.sess)
.map(|s| s.to_string())
.chain(