intel/llvm
1
0
Fork 0
mirror of https://github.com/intel/llvm.git synced 2026-01-26 21:53:12 +08:00
Code Issues Packages Projects Releases Wiki Activity

[nfc][InstrProfiling]For comdat setting helper function, move comment closer to the code (#83757)

Browse Source
This commit is contained in:
Mingming Liu
2024-03-04 09:46:34 -08:00
committed by GitHub
parent bd7bce2c84
commit 87e7140f72
1 changed files with 29 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

50
llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
View File

@@ -208,6 +208,7 @@ private:
std::function<const TargetLibraryInfo &(Function &F)> GetTLI;
const bool DataReferencedByCode;
struct PerFunctionProfileData {
uint32_t NumValueSites[IPVK_Last + 1] = {};
GlobalVariable *RegionCounters = nullptr;
@@ -1193,18 +1194,41 @@ static bool needsRuntimeRegistrationOfSectionRange(const Triple &TT) {
}
void InstrLowerer::maybeSetComdat(GlobalVariable *GV, Function *Fn,
StringRef VarName) {
StringRef CounterGroupName) {
// Place lowered global variables in a comdat group if the associated function
// is a COMDAT. This will make sure that only one copy of global variable
// (e.g. function counters) of the COMDAT function will be emitted after
// linking.
bool NeedComdat = needsComdatForCounter(*Fn, M);
bool UseComdat = (NeedComdat || TT.isOSBinFormatELF());
if (!UseComdat)
return;
StringRef GroupName =
TT.isOSBinFormatCOFF() && DataReferencedByCode ? GV->getName() : VarName;
// Keep in mind that this pass may run before the inliner, so we need to
// create a new comdat group (for counters, profiling data, etc). If we use
// the comdat of the parent function, that will result in relocations against
// discarded sections.
//
// If the data variable is referenced by code, non-counter variables (notably
// profiling data) and counters have to be in different comdats for COFF
// because the Visual C++ linker will report duplicate symbol errors if there
// are multiple external symbols with the same name marked
// IMAGE_COMDAT_SELECT_ASSOCIATIVE.
StringRef GroupName = TT.isOSBinFormatCOFF() && DataReferencedByCode
? GV->getName()
: CounterGroupName;
Comdat *C = M.getOrInsertComdat(GroupName);
if (!NeedComdat)
if (!NeedComdat) {
// Object file format must be ELF since `UseComdat && !NeedComdat` is true.
//
// For ELF, when not using COMDAT, put counters, data and values into a
// nodeduplicate COMDAT which is lowered to a zero-flag section group. This
// allows -z start-stop-gc to discard the entire group when the function is
// discarded.
C->setSelectionKind(Comdat::NoDeduplicate);
}
GV->setComdat(C);
// COFF doesn't allow the comdat group leader to have private linkage, so
// upgrade private linkage to internal linkage to produce a symbol table
@@ -1238,23 +1262,7 @@ GlobalVariable *InstrLowerer::setupProfileSection(InstrProfInstBase *Inc,
Linkage = GlobalValue::PrivateLinkage;
Visibility = GlobalValue::DefaultVisibility;
}
// Move the name variable to the right section. Place them in a COMDAT group
// if the associated function is a COMDAT. This will make sure that only one
// copy of counters of the COMDAT function will be emitted after linking. Keep
// in mind that this pass may run before the inliner, so we need to create a
// new comdat group for the counters and profiling data. If we use the comdat
// of the parent function, that will result in relocations against discarded
// sections.
//
// If the data variable is referenced by code, counters and data have to be
// in different comdats for COFF because the Visual C++ linker will report
// duplicate symbol errors if there are multiple external symbols with the
// same name marked IMAGE_COMDAT_SELECT_ASSOCIATIVE.
//
// For ELF, when not using COMDAT, put counters, data and values into a
// nodeduplicate COMDAT which is lowered to a zero-flag section group. This
// allows -z start-stop-gc to discard the entire group when the function is
// discarded.
// Move the name variable to the right section.
bool Renamed;
GlobalVariable *Ptr;
StringRef VarPrefix;