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Differential D25339

[PGO] Create weak alias for the renamed Comdat function
ClosedPublic

Authored by xur on Oct 6 2016, 11:45 AM.

Details

Reviewers
davidxl
Commits
rG0e79f7d11d6a: [PGO] Create weak alias for the renamed Comdat function
rL283490: [PGO] Create weak alias for the renamed Comdat function
Summary

Add a weak alias to the renamed Comdat function in IR level instrumentation, using it's original name. This ensures the same behavior w/ and w/o IR instrumentation, even for non standard conforming code.

Diff Detail

Event Timeline

xur updated this revision to Diff 73827.Oct 6 2016, 11:45 AM
xur retitled this revision from to [PGO] Create weak alias for the renamed Comdat function.
xur updated this object.
xur added a reviewer: davidxl.
xur added a subscriber: llvm-commits.
davidxl accepted this revision.Oct 6 2016, 1:40 PM
davidxl edited edge metadata.

lgtm

This revision is now accepted and ready to land.Oct 6 2016, 1:40 PM
Closed by commit rL283490: [PGO] Create weak alias for the renamed Comdat function (authored by xur). · Explain WhyOct 6 2016, 1:47 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents

PathSize
lib/
Transforms/
Instrumentation/
4 lines
test/
Transforms/
PGOProfile/
6 lines

Diff 73827

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

Context not available.
void FuncPGOInstrumentation<Edge, BBInfo>::renameComdatFunction() { void FuncPGOInstrumentation<Edge, BBInfo>::renameComdatFunction() {
if (!canRenameComdat(F, ComdatMembers)) if (!canRenameComdat(F, ComdatMembers))
return; return;
std::string OrigName = F.getName().str();
std::string NewFuncName = std::string NewFuncName =
Twine(F.getName() + "." + Twine(FunctionHash)).str(); Twine(F.getName() + "." + Twine(FunctionHash)).str();
F.setName(Twine(NewFuncName)); F.setName(Twine(NewFuncName));
GlobalAlias::create(GlobalValue::WeakAnyLinkage, OrigName, &F);
FuncName = Twine(FuncName + "." + Twine(FunctionHash)).str(); FuncName = Twine(FuncName + "." + Twine(FunctionHash)).str();
Comdat *NewComdat; Comdat *NewComdat;
Module *M = F.getParent(); Module *M = F.getParent();
Context not available.
if (GlobalAlias *GA = dyn_cast<GlobalAlias>(CM.second)) { if (GlobalAlias *GA = dyn_cast<GlobalAlias>(CM.second)) {
// For aliases, change the name directly. // For aliases, change the name directly.
assert(dyn_cast<Function>(GA->getAliasee()->stripPointerCasts()) == &F); assert(dyn_cast<Function>(GA->getAliasee()->stripPointerCasts()) == &F);
std::string OrigGAName = GA->getName().str();
GA->setName(Twine(GA->getName() + "." + Twine(FunctionHash))); GA->setName(Twine(GA->getName() + "." + Twine(FunctionHash)));
GlobalAlias::create(GlobalValue::WeakAnyLinkage, OrigGAName, GA);
continue; continue;
} }
// Must be a function. // Must be a function.
Context not available.

test/Transforms/PGOProfile/comdat_rename.ll

Context not available.
; Rename AvailableExternallyLinkage functions ; Rename AvailableExternallyLinkage functions
; ELFONLY-DAG: $aef.[[SINGLEBB_HASH]] = comdat any ; ELFONLY-DAG: $aef.[[SINGLEBB_HASH]] = comdat any
; ELFONLY: @f = weak alias void (), void ()* @f.[[SINGLEBB_HASH]]
; ELFONLY: @f_with_alias = weak alias void (), void ()* @f_with_alias.[[SINGLEBB_HASH]]
; ELFONLY: @af = weak alias void (...), void (...)* @af.[[SINGLEBB_HASH]]
; ELFONLY: @aef = weak alias void (), void ()* @aef.[[SINGLEBB_HASH]]
define available_externally void @aef() { define available_externally void @aef() {
; ELFONLY: define linkonce_odr void @aef.[[SINGLEBB_HASH]]() comdat { ; ELFONLY: define linkonce_odr void @aef.[[SINGLEBB_HASH]]() comdat {
; COFFONLY: define available_externally void @aef() { ; COFFONLY: define available_externally void @aef() {
Context not available.