Auto merge of #86020 - nagisa:nagisa/outliner, r=pnkfelix

Disable the machine outliner by default

This addresses a codegen-issue that needs to be fixed upstream in LLVM.
While we wait for the fix, we can disable it.

Verified manually that the outliner is no longer run when
`-Copt-level=z` is specified, and also that you can override this with
`-Cllvm-args=-enable-machine-outliner` if you need it anyway.

A regression test is not really feasible in this instance, given that we
do not have any minimal reproducers.

Fixes #85351

cc `@pnkfelix`
This commit is contained in:
bors 2021-06-10 15:11:01 +00:00
commit 1f949e94e8

View File

@ -1,5 +1,5 @@
use crate::back::write::create_informational_target_machine;
use crate::llvm;
use crate::{llvm, llvm_util};
use libc::c_int;
use rustc_codegen_ssa::target_features::supported_target_features;
use rustc_data_structures::fx::FxHashSet;
@ -84,6 +84,17 @@ unsafe fn configure_llvm(sess: &Session) {
if !sess.opts.debugging_opts.no_generate_arange_section {
add("-generate-arange-section", false);
}
// FIXME(nagisa): disable the machine outliner by default in LLVM versions 11, where it was
// introduced and up.
//
// This should remain in place until https://reviews.llvm.org/D103167 is fixed. If LLVM
// has been upgraded since, consider adjusting the version check below to contain an upper
// bound.
if llvm_util::get_version() >= (11, 0, 0) {
add("-enable-machine-outliner=never", false);
}
match sess.opts.debugging_opts.merge_functions.unwrap_or(sess.target.merge_functions) {
MergeFunctions::Disabled | MergeFunctions::Trampolines => {}
MergeFunctions::Aliases => {