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Always include global target features in function attributes

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This ensures that information about target features configured with
`-C target-feature=...` or detected with `-C target-cpu=native` is
retained for subsequent consumers of LLVM bitcode.

This is crucial for linker plugin LTO, since this information is not
conveyed to the plugin otherwise.
This commit is contained in:
Tomasz Miąsko 2022-03-03 00:00:00 +00:00
parent b6f845f225
commit 095d818e0c
2 changed files with 9 additions and 10 deletions
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13
compiler/rustc_codegen_llvm/src/attributes.rs
View File

@ -378,13 +378,12 @@ pub fn from_fn_attrs<'ll, 'tcx>(
}
}
if !function_features.is_empty() {
let global_features = cx.tcx.global_backend_features(()).iter().map(|s| &s[..]);
let val = global_features
.chain(function_features.iter().map(|s| &s[..]))
.intersperse(",")
.collect::<SmallStr<1024>>();
to_add.push(llvm::CreateAttrStringValue(cx.llcx, "target-features", &val));
let global_features = cx.tcx.global_backend_features(()).iter().map(|s| s.as_str());
let function_features = function_features.iter().map(|s| s.as_str());
let target_features =
global_features.chain(function_features).intersperse(",").collect::<SmallStr<1024>>();
if !target_features.is_empty() {
to_add.push(llvm::CreateAttrStringValue(cx.llcx, "target-features", &target_features));
}
attributes::apply_to_llfn(llfn, Function, &to_add);

6
src/test/codegen/target-feature-overrides.rs
View File

@ -29,7 +29,7 @@ pub unsafe fn apple() -> u32 {
peach()
}
// target features same as global (not reflected or overriden in IR)
// target features same as global
#[no_mangle]
pub unsafe fn banana() -> u32 {
// CHECK-LABEL: @banana()
@ -43,5 +43,5 @@ pub unsafe fn banana() -> u32 {
// COMPAT-SAME: "target-features"="+avx2,+avx,+avx"
// INCOMPAT-SAME: "target-features"="-avx2,-avx,+avx"
// CHECK: attributes [[BANANAATTRS]]
// CHECK-NOT: target-features
// CHECK-SAME: }
// COMPAT-SAME: "target-features"="+avx2,+avx"
// INCOMPAT-SAME: "target-features"="-avx2,-avx"