[PGO] refactor PGOFuncName meta data code to be used in clang

[xur]

Summary

Refactor the code that gets and creates PGOFuncName meta data so that it can be used in clang's value profile annotation.

[davidxl]

include/llvm/ProfileData/InstrProf.h

250

clang-format it.

-->getPGOFuncNameMetaDataKind()

262

Not suitable for being an 'inline' function. Put the def in InstrProf.cpp.

[xur]

Updated with David's comments.

[vsk]

Thanks --

include/llvm/ProfileData/InstrProf.h

250

nit 1: MetaData -> Metadata, I'd prefer to preserve consistency with the existing naming convention.
nit 2: MetaDataKind -> MetadataName, since enum MetadataKind already exists, and this could cause confusion.

257

nit: "Write out" -> "Create"

[xur]

Updated the patch with vsk@'s review comments.

Thanks!

-Rong

[davidxl]

sort the header file order properly.

include/llvm/ProfileData/InstrProf.h

258

apply to internal linkage functions declared by user only.

lib/ProfileData/InstrProf.cpp

102

In LTO mode or When InLTO is true

[xur]

More comments change suggested by David.

Thanks,

-Rong

[davidxl]

lgtm

The return value of createPGOFunctionMetadata is not used -- consider dropping it.

[xur]

drop the return value of reatePGOFuncNameMetadata().

If I don't here other review comments, I'll commit ater today.

Thanks,

-Rong

include/llvm/ProfileData/InstrProf.h

 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_PROFILEDATA_INSTRPROF_H
 #define LLVM_PROFILEDATA_INSTRPROF_H
 
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSet.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Metadata.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/ProfileData/InstrProfData.inc"
 #include "llvm/ProfileData/ProfileCommon.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/MD5.h"
 #include "llvm/Support/MathExtras.h"

 /// value profile meta data. Return false if there is no value data annotated,
 /// otherwise  return true.
 bool getValueProfDataFromInst(const Instruction &Inst,
                               InstrProfValueKind ValueKind,
                               uint32_t MaxNumValueData,
                               InstrProfValueData ValueData[],
                               uint32_t &ActualNumValueData, uint64_t &TotalC);
 
+inline StringRef PGOFuncNameMetaData(){
+  return "PGOFuncName";
+}
+
+/// Return the PGOFuncName meta data associated with a function.
+inline MDNode *getPGOFuncNameMetaData(const Function &F) {
+  return F.getMetadata(PGOFuncNameMetaData());
+}
+
+/// Write out the PGOFuncName meta data if PGOFuncName is different from
+/// function's raw name. This should only apply to internal linkage functions
+/// only. Return true if the meta data is written out, and false if not.
+inline bool createPGOFuncNameMetaData(Function &F) {
+  const std::string &FuncName = getPGOFuncName(F);
+  if (FuncName == F.getName())
+    return false;
+
+  LLVMContext &C = F.getContext();
+  MDNode *N = MDNode::get(C, MDString::get(C, FuncName.c_str()));
+  F.setMetadata(PGOFuncNameMetaData(), N); 
+  return true;
+}
+
 const std::error_category &instrprof_category();
 
 enum class instrprof_error {
   success = 0,
   eof,
   unrecognized_format,
   bad_magic,
   bad_header,

lib/ProfileData/InstrProf.cpp

 // (PGOUseFunc::annotateIndirectCallSites). If a symbol does not have the meta
 // data, its original linkage must be non-internal.
 std::string getPGOFuncName(const Function &F, bool InLTO, uint64_t Version) {
   if (!InLTO)
     return getPGOFuncName(F.getName(), F.getLinkage(), F.getParent()->getName(),
                           Version);
 
   // InLTO mode. First check if these is a meta data.
-  MDNode *MD = F.getMetadata("PGOFuncName");
-  if (MD != nullptr) {
+  if (MDNode *MD = getPGOFuncNameMetaData(F)) {
     StringRef S = cast<MDString>(MD->getOperand(0))->getString();
     return S.str();
   }
 
   // If there is no meta data, the function must be a global before the value
   // profile annotation pass. Its current linkage may be internal if it is
   // internalized in LTO mode.
-  return getPGOFuncName (F.getName(), GlobalValue::ExternalLinkage, "");
+  return getPGOFuncName(F.getName(), GlobalValue::ExternalLinkage, "");
 }
 
 StringRef getFuncNameWithoutPrefix(StringRef PGOFuncName, StringRef FileName) {
   if (FileName.empty())
     return PGOFuncName;
   // Drop the file name including ':'. See also getPGOFuncName.
   if (PGOFuncName.startswith(FileName))
     PGOFuncName = PGOFuncName.drop_front(FileName.size() + 1);

lib/Transforms/Instrumentation/PGOInstrumentation.cpp

void PGOUseFunc::setBranchWeights() {
   }
 }
 
 // Traverse all the indirect callsites and annotate the instructions.
 void PGOUseFunc::annotateIndirectCallSites() {
   if (DisableValueProfiling)
     return;
 
-  // Write out the PGOFuncName if this is different from it's raw name.
-  // This should only apply to internal linkage functions only.
-  const std::string &FuncName = getPGOFuncName(F);
-  if (FuncName != F.getName()) {
-    LLVMContext &C = F.getContext();
-    MDNode *N = MDNode::get(C, MDString::get(C, FuncName.c_str()));
-    F.setMetadata("PGOFuncName", N);
-  }
+  // Write out the PGOFuncName meta data.
+  createPGOFuncNameMetaData(F);
 
   unsigned IndirectCallSiteIndex = 0;
   PGOIndirectCallSiteVisitor ICV;
   ICV.visit(F);
   unsigned NumValueSites =
       ProfileRecord.getNumValueSites(IPVK_IndirectCallTarget);
   if (NumValueSites != ICV.IndirectCallInsts.size()) {
     std::string Msg =