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mark calls in the unwind path as !noinline

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The unwind path is always cold, so that should not have bad performance
implications.  This avoids catastrophic exponential inlining, and also
decreases the size of librustc.so by 1.5% (OTOH, the size of `libstd.so`
increased by 0.5% for some reason).

Fixes #41696.
This commit is contained in:
Ariel Ben-Yehuda 2017-06-20 15:07:47 +03:00
parent 1143eb26a2
commit 0b93798959
2 changed files with 7 additions and 2 deletions
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7
src/librustc_trans/mir/block.rs
View file

@ -146,6 +146,13 @@ fn trans_terminator(&mut self,
} else {
let llret = bcx.call(fn_ptr, &llargs, cleanup_bundle);
fn_ty.apply_attrs_callsite(llret);
if this.mir[bb].is_cleanup {
// Cleanup is always the cold path. Don't inline
// drop glue. Also, when there is a deeply-nested
// struct, there are "symmetry" issues that cause
// exponential inlining - see issue #41696.
llvm::Attribute::NoInline.apply_callsite(llvm::AttributePlace::Function, llret);
}
if let Some((ret_dest, ret_ty, target)) = destination {
let op = OperandRef {

2
src/test/run-pass/issue-41696.rs
View file

@ -9,8 +9,6 @@
// except according to those terms.
// this used to cause exponential code-size blowup during LLVM passes.
// ignore-test FIXME #41696
// min-llvm-version 3.9
#![feature(test)]