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[CSSPGO] Avoid repeatedly computing md5 hash code for pseudo probe inline contexts. 

Md5 hashing is expansive. Using a hash map to look up already computed GUID for dwarf names. Saw a 2% build time improvement on an internal large application.

Reviewed By: wenlei

Differential Revision: https://reviews.llvm.org/D108722
This commit is contained in:
Hongtao Yu 2021-08-25 11:57:48 -07:00
parent 881677b58a
commit f39256e3a5
2 changed files with 9 additions and 1 deletions
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7
llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.cpp
View File

@ -20,6 +20,8 @@
using namespace llvm;
PseudoProbeHandler::~PseudoProbeHandler() = default;
void PseudoProbeHandler::emitPseudoProbe(uint64_t Guid, uint64_t Index,
uint64_t Type, uint64_t Attr,
const DILocation *DebugLoc) {
@ -35,7 +37,10 @@ void PseudoProbeHandler::emitPseudoProbe(uint64_t Guid, uint64_t Index,
auto Name = SP->getLinkageName();
if (Name.empty())
Name = SP->getName();
uint64_t CallerGuid = Function::getGUID(Name);
// Use caching to avoid redundant md5 computation for build speed.
uint64_t &CallerGuid = NameGuidMap[Name];
if (!CallerGuid)
CallerGuid = Function::getGUID(Name);
uint64_t CallerProbeId = PseudoProbeDwarfDiscriminator::extractProbeIndex(
InlinedAt->getDiscriminator());
ReversedInlineStack.emplace_back(CallerGuid, CallerProbeId);

3
llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.h
View File

@ -26,9 +26,12 @@ class DILocation;
class PseudoProbeHandler : public AsmPrinterHandler {
// Target of pseudo probe emission.
AsmPrinter *Asm;
// Name to GUID map, used as caching/memoization for speed.
DenseMap<StringRef, uint64_t> NameGuidMap;
public:
PseudoProbeHandler(AsmPrinter *A) : Asm(A){};
~PseudoProbeHandler() override;
void emitPseudoProbe(uint64_t Guid, uint64_t Index, uint64_t Type,
uint64_t Attr, const DILocation *DebugLoc);