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Differential D70925

Place the "cold" code piece into the same section as the original function
ClosedPublic

Authored by void on Dec 2 2019, 2:17 PM.

Details

Reviewers
compnerd
vsk
tejohnson
Commits
rG87f146767ed7: Place the "cold" code piece into the same section as the original function
Summary

This cropped up in the Linux kernel where cold code was placed in an
incompatible section.

Diff Detail

Event Timeline

void created this revision.Dec 2 2019, 2:17 PM
Herald added a project: Restricted Project. · View Herald TranscriptDec 2 2019, 2:17 PM
Herald added subscribers: llvm-commits, hiraditya. · View Herald Transcript
Harbormaster completed remote builds in B41744: Diff 231779.Dec 2 2019, 2:20 PM
vsk accepted this revision.Dec 2 2019, 3:09 PM

Thanks, LGTM.

This revision is now accepted and ready to land.Dec 2 2019, 3:09 PM
Closed by commit rG87f146767ed7: Place the "cold" code piece into the same section as the original function (authored by void). · Explain WhyDec 2 2019, 3:25 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents

PathSize
llvm/
lib/
Transforms/
IPO/
3 lines
test/
Transforms/
HotColdSplit/
33 lines

Diff 231779

llvm/lib/Transforms/IPO/HotColdSplitting.cpp

Show First 20 Lines • Show All 322 Lines • ▼ Show 20 Lines if (Function *OutF = CE.extractCodeRegion(CEAC)) {
CallSite CS(CI); CallSite CS(CI);
NumColdRegionsOutlined++; NumColdRegionsOutlined++;
if (TTI.useColdCCForColdCall(*OutF)) { if (TTI.useColdCCForColdCall(*OutF)) {
OutF->setCallingConv(CallingConv::Cold); OutF->setCallingConv(CallingConv::Cold);
CS.setCallingConv(CallingConv::Cold); CS.setCallingConv(CallingConv::Cold);
} }
CI->setIsNoInline(); CI->setIsNoInline();
if (OrigF->hasSection())
OutF->setSection(OrigF->getSection());
markFunctionCold(*OutF, BFI != nullptr); markFunctionCold(*OutF, BFI != nullptr);
LLVM_DEBUG(llvm::dbgs() << "Outlined Region: " << *OutF); LLVM_DEBUG(llvm::dbgs() << "Outlined Region: " << *OutF);
ORE.emit([&]() { ORE.emit([&]() {
return OptimizationRemark(DEBUG_TYPE, "HotColdSplit", return OptimizationRemark(DEBUG_TYPE, "HotColdSplit",
&*Region[0]->begin()) &*Region[0]->begin())
<< ore::NV("Original", OrigF) << " split cold code into " << ore::NV("Original", OrigF) << " split cold code into "
<< ore::NV("Split", OutF); << ore::NV("Split", OutF);
▲ Show 20 Lines • Show All 398 Lines • Show Last 20 Lines

llvm/test/Transforms/HotColdSplit/retain-section.ll

  • This file was added.
; RUN: opt -hotcoldsplit -hotcoldsplit-threshold=0 -S < %s | FileCheck %s
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.14.0"
; Retain section after cold code is split off.
; CHECK-LABEL: @fun
; CHECK: call void @fun.cold.1{{.*}} section ".text.cold"
define void @fun() section ".text.cold" {
entry:
br i1 undef, label %if.then, label %if.else
if.then:
ret void
if.else:
call void @sink()
ret void
}
; CHECK: define {{.*}} @foo{{.*}}#[[outlined_func_attr:[0-9]+]]
define void @foo() cold {
ret void
}
declare void @sink() cold
; CHECK: define {{.*}} @fun.cold.1{{.*}}#[[outlined_func_attr]]
; CHECK: attributes #[[outlined_func_attr]] = {
; CHECK-SAME: cold
; CHECK-SAME: minsize