[CSSPGO] Fix repeated reading of profile metadata

Author: wlei-llvm

llvm/include/llvm/ProfileData/SampleProfReader.h

@@ -777,7 +777,7 @@ class SampleProfileReaderExtBinaryBase : public SampleProfileReaderBinary {
   std::error_code readSecHdrTable();
 
   std::error_code readFuncMetadata(bool ProfileHasAttribute,
-                                   SampleProfileMap &Profiles);
+                                   DenseSet<FunctionSamples *> &Profiles);
   std::error_code readFuncMetadata(bool ProfileHasAttribute);
   std::error_code readFuncMetadata(bool ProfileHasAttribute,
                                    FunctionSamples *FProfile);

llvm/lib/ProfileData/SampleProfReader.cpp

@@ -831,8 +831,15 @@ SampleProfileReaderExtBinaryBase::read(const DenseSet<StringRef> &FuncsToUse,
   if (std::error_code EC = readFuncProfiles(FuncsToUse, Profiles))
     return EC;
   End = Data;
+  DenseSet<FunctionSamples *> ProfilesToReadMetadata;
+  for (auto FName : FuncsToUse) {
+    auto I = Profiles.find(FName);
+    if (I != Profiles.end())
+      ProfilesToReadMetadata.insert(&I->second);
+  }
 
-  if (std::error_code EC = readFuncMetadata(ProfileHasAttribute, Profiles))
+  if (std::error_code EC =
+          readFuncMetadata(ProfileHasAttribute, ProfilesToReadMetadata))
     return EC;
   return sampleprof_error::success;
 }
@@ -1300,14 +1307,12 @@ SampleProfileReaderExtBinaryBase::readFuncMetadata(bool ProfileHasAttribute,
   return sampleprof_error::success;
 }
 
-std::error_code
-SampleProfileReaderExtBinaryBase::readFuncMetadata(bool ProfileHasAttribute,
-                                                   SampleProfileMap &Profiles) {
+std::error_code SampleProfileReaderExtBinaryBase::readFuncMetadata(
+    bool ProfileHasAttribute, DenseSet<FunctionSamples *> &Profiles) {
   if (FuncMetadataIndex.empty())
     return sampleprof_error::success;
 
-  for (auto &I : Profiles) {
-    FunctionSamples *FProfile = &I.second;
+  for (auto *FProfile : Profiles) {
     auto R = FuncMetadataIndex.find(FProfile->getContext().getHashCode());
     if (R == FuncMetadataIndex.end())
       continue;