[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 ↗

(On Diff #52123)

clang-format it.

-->getPGOFuncNameMetaDataKind()

262 ↗

(On Diff #52123)

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 ↗

(On Diff #52129)

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 ↗

(On Diff #52129)

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 ↗

(On Diff #52133)

apply to internal linkage functions declared by user only.

lib/ProfileData/InstrProf.cpp

101 ↗

(On Diff #52133)

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

llvm/trunk/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/GlobalValue.h"
+#include "llvm/IR/Metadata.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"
 #include <cstdint>

 /// 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 getPGOFuncNameMetadataName() { return "PGOFuncName"; }
+
+/// Return the PGOFuncName meta data associated with a function.
+inline MDNode *getPGOFuncNameMetadata(const Function &F) {
+  return F.getMetadata(getPGOFuncNameMetadataName());
+}
+
+/// Create the PGOFuncName meta data if PGOFuncName is different from
+/// function's raw name. This should only apply to internal linkage functions
+/// declared by users only.
+void createPGOFuncNameMetadata(Function &F);
+
 const std::error_category &instrprof_category();
 
 enum class instrprof_error {
   success = 0,
   eof,
   unrecognized_format,
   bad_magic,
   bad_header,

llvm/trunk/lib/ProfileData/InstrProf.cpp

 // symbols in the value profile annotation step
 // (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) {
+  // In LTO mode (when InLTO is true), first check if there is a meta data.
+  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);
for (unsigned I = 3; I < NOps; I += 2) {
     if (!Value || !Count)
       return false;
     ValueData[ActualNumValueData].Value = Value->getZExtValue();
     ValueData[ActualNumValueData].Count = Count->getZExtValue();
     ActualNumValueData++;
   }
   return true;
 }
+
+void createPGOFuncNameMetadata(Function &F) {
+  const std::string &FuncName = getPGOFuncName(F);
+  if (FuncName == F.getName())
+    return;
+
+  LLVMContext &C = F.getContext();
+  MDNode *N = MDNode::get(C, MDString::get(C, FuncName.c_str()));
+  F.setMetadata(getPGOFuncNameMetadataName(), N);
+}
+
 } // end namespace llvm

llvm/trunk/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);
-  }
+  // Create 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 =