[SampleFDO] Set ProfileIsFS bit properly in extbinary format from the internal option

[xur]

Summary

We have "-profile-isfs" internal option for text, binary, and compactbinary format (mostly for debug and test purpose).
We need to set the related flag in FunctionSamples so that ProfileIsFS is written to the header in extbinary format.

[xur]

Thanks Wenlei for the fast response!

-Rong

[xur]

Wenlei / Hongtao / Lei,

Wei committed the FSAFDO tool part of change to GitHub yesterday. Sorry for
taking so long.

I'm wondering if you can port the change to llvm-profgen and do some
experiments with FSAFDO. Let me know if there anything that I can help with.

Best regards,

-Rong

[MaskRay]

llvm/lib/ProfileData/SampleProfReader.cpp

254

Writes to the static data member ProfileIsFS is racy: ThinLTO may creates multiple InProcessThinBackend instances and backends may run the code concurrently.

llvm/lib/ProfileData/SampleProfReader.cpp

std::error_code SampleProfileReaderText::readImpl() {
   InlineCallStack InlineStack;
   uint32_t ProbeProfileCount = 0;
 
   // SeenMetadata tracks whether we have processed metadata for the current
   // top-level function profile.
   bool SeenMetadata = false;
 
   ProfileIsFS = ProfileIsFSDisciminator;
+  FunctionSamples::ProfileIsFS = ProfileIsFS;
   for (; !LineIt.is_at_eof(); ++LineIt) {
     if ((*LineIt)[(*LineIt).find_first_not_of(' ')] == '#')
       continue;
     // Read the header of each function.
     //
     // Note that for function identifiers we are actually expecting
     // mangled names, but we may not always get them. This happens when
     // the compiler decides not to emit the function (e.g., it was inlined
SampleProfileReaderBinary::readFuncProfile(const uint8_t *Start) {
 
   if (std::error_code EC = readProfile(FProfile))
     return EC;
   return sampleprof_error::success;
 }
 
 std::error_code SampleProfileReaderBinary::readImpl() {
   ProfileIsFS = ProfileIsFSDisciminator;
+  FunctionSamples::ProfileIsFS = ProfileIsFS;
   while (!at_eof()) {
     if (std::error_code EC = readFuncProfile(Data))
       return EC;
   }
 
   return sampleprof_error::success;
 }
 
std::error_code SampleProfileReaderExtBinaryBase::readImpl() {
   return sampleprof_error::success;
 }
 
 std::error_code SampleProfileReaderCompactBinary::readImpl() {
   // Collect functions used by current module if the Reader has been
   // given a module.
   bool LoadFuncsToBeUsed = collectFuncsFromModule();
   ProfileIsFS = ProfileIsFSDisciminator;
+  FunctionSamples::ProfileIsFS = ProfileIsFS;
   std::vector<uint64_t> OffsetsToUse;
   if (!LoadFuncsToBeUsed) {
     // load all the function profiles.
     for (auto FuncEntry : FuncOffsetTable) {
       OffsetsToUse.push_back(FuncEntry.second);
     }
   } else {
     // load function profiles on demand.

llvm/test/tools/llvm-profdata/sample-fs.test

 RUN: llvm-profdata show --sample %p/Inputs/sample-fs.proftext -profile-isfs -fs-discriminator-pass=Base -o %t2-text
 RUN: diff %t2-binary %t2-text
 
 3- Merge command and keep only the base discriminator bits and first pass of FS discriminator
 RUN: llvm-profdata merge --sample %p/Inputs/sample-fs.proftext -profile-isfs -fs-discriminator-pass=Pass1 --binary -o - | llvm-profdata show --sample - -o %t3-binary
 RUN: llvm-profdata show --sample %p/Inputs/sample-fs.proftext -profile-isfs -fs-discriminator-pass=Pass1 -o %t3-text
 RUN: diff %t3-binary %t3-text
 
+4- ProfileIsFS is set properly in extbinary format from the internal option
+RUN: llvm-profdata merge --sample %p/Inputs/sample-fs.proftext -profile-isfs --extbinary -o %t_extbin.afdo
+RUN: llvm-profdata show --sample --show-sec-info-only %t_extbin.afdo | FileCheck %s --check-prefix=ISFSSET
+ISFSSET: Flags: {fs-discriminator}