[llvm] f39256e - [CSSPGO] Avoid repeatedly computing md5 hash code for pseudo probe inline contexts.
Hongtao Yu via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 30 10:12:07 PDT 2021
Author: Hongtao Yu
Date: 2021-08-30T10:11:47-07:00
New Revision: f39256e3a5dd1f3d7311703003608340ffdb42bc
URL: https://github.com/llvm/llvm-project/commit/f39256e3a5dd1f3d7311703003608340ffdb42bc
DIFF: https://github.com/llvm/llvm-project/commit/f39256e3a5dd1f3d7311703003608340ffdb42bc.diff
LOG: [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
Added:
Modified:
llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.cpp
llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.h
Removed:
################################################################################
diff --git a/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.cpp
index 35a830f416f6..9e6f1a537de3 100644
--- a/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.cpp
@@ -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);
diff --git a/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.h b/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.h
index f2026a118bf5..7d5e51218693 100644
--- a/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.h
+++ b/llvm/lib/CodeGen/AsmPrinter/PseudoProbePrinter.h
@@ -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);
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