[PGO] InstrPGO and coverage code refactoring (NFC)

Introduce a new class InstrProfSymtab to abstract
the PGO symbol table for prof and coverage reader.
The symtab is is to lookup function's PGO name
using function keys. The first user of the class
is CoverageMapping Reader. More will follow.

llvm-svn: 255862

1 files changed, 33 insertions, 46 deletions

diff --git a/llvm/lib/ProfileData/CoverageMappingReader.cpp b/llvm/lib/ProfileData/CoverageMappingReader.cpp
index ed737d8f04e..3f59136d088 100644
--- a/llvm/lib/ProfileData/CoverageMappingReader.cpp
+++ b/llvm/lib/ProfileData/CoverageMappingReader.cpp
@@ -290,36 +290,25 @@ std::error_code RawCoverageMappingReader::read() {
   return std::error_code();
 }
 
-namespace {
-
-/// \brief A helper structure to access the data from a section
-/// in an object file.
-struct SectionData {
-  StringRef Data;
-  uint64_t Address;
-
-  std::error_code load(SectionRef &Section) {
-    if (auto Err = Section.getContents(Data))
-      return Err;
-    Address = Section.getAddress();
-    return std::error_code();
-  }
+std::error_code InstrProfSymtab::create(SectionRef &Section) {
+  if (auto Err = Section.getContents(Data))
+    return Err;
+  Address = Section.getAddress();
+  return std::error_code();
+}
 
-  std::error_code get(uint64_t Pointer, size_t Size, StringRef &Result) {
-    if (Pointer < Address)
-      return coveragemap_error::malformed;
-    auto Offset = Pointer - Address;
-    if (Offset + Size > Data.size())
-      return coveragemap_error::malformed;
-    Result = Data.substr(Pointer - Address, Size);
-    return std::error_code();
-  }
-};
+StringRef InstrProfSymtab::getFuncName(uint64_t Pointer, size_t Size) {
+  if (Pointer < Address)
+    return StringRef();
+  auto Offset = Pointer - Address;
+  if (Offset + Size > Data.size())
+    return StringRef();
+  return Data.substr(Pointer - Address, Size);
 }
 
 template <typename T, support::endianness Endian>
 std::error_code readCoverageMappingData(
-    SectionData &ProfileNames, StringRef Data,
+    InstrProfSymtab &ProfileNames, StringRef Data,
     std::vector<BinaryCoverageReader::ProfileMappingRecord> &Records,
     std::vector<StringRef> &Filenames) {
   using namespace support;
@@ -389,9 +378,9 @@ std::error_code readCoverageMappingData(
         continue;
 
       // Finally, grab the name and create a record.
-      StringRef FuncName;
-      if (std::error_code EC = ProfileNames.get(NamePtr, NameSize, FuncName))
-        return EC;
+      StringRef FuncName = ProfileNames.getFuncName(NamePtr, NameSize);
+      if (NameSize && FuncName.empty())
+        return coveragemap_error::malformed;
       Records.push_back(BinaryCoverageReader::ProfileMappingRecord(
           CoverageMappingVersion(Version), FuncName, FuncHash, Mapping,
           FilenamesBegin, Filenames.size() - FilenamesBegin));
@@ -404,7 +393,7 @@ std::error_code readCoverageMappingData(
 static const char *TestingFormatMagic = "llvmcovmtestdata";
 
 static std::error_code loadTestingFormat(StringRef Data,
-                                         SectionData &ProfileNames,
+                                         InstrProfSymtab &ProfileNames,
                                          StringRef &CoverageMapping,
                                          uint8_t &BytesInAddress,
                                          support::endianness &Endian) {
@@ -423,14 +412,14 @@ static std::error_code loadTestingFormat(StringRef Data,
   if (Data.size() < 1)
     return coveragemap_error::truncated;
   N = 0;
-  ProfileNames.Address =
+  uint64_t Address =
       decodeULEB128(reinterpret_cast<const uint8_t *>(Data.data()), &N);
   if (N > Data.size())
     return coveragemap_error::malformed;
   Data = Data.substr(N);
   if (Data.size() < ProfileNamesSize)
     return coveragemap_error::malformed;
-  ProfileNames.Data = Data.substr(0, ProfileNamesSize);
+  ProfileNames.create(Data.substr(0, ProfileNamesSize), Address);
   CoverageMapping = Data.substr(ProfileNamesSize);
   return std::error_code();
 }
@@ -446,12 +435,10 @@ static ErrorOr<SectionRef> lookupSection(ObjectFile &OF, StringRef Name) {
   return coveragemap_error::no_data_found;
 }
 
-static std::error_code loadBinaryFormat(MemoryBufferRef ObjectBuffer,
-                                        SectionData &ProfileNames,
-                                        StringRef &CoverageMapping,
-                                        uint8_t &BytesInAddress,
-                                        support::endianness &Endian,
-                                        StringRef Arch) {
+static std::error_code
+loadBinaryFormat(MemoryBufferRef ObjectBuffer, InstrProfSymtab &ProfileNames,
+                 StringRef &CoverageMapping, uint8_t &BytesInAddress,
+                 support::endianness &Endian, StringRef Arch) {
   auto BinOrErr = object::createBinary(ObjectBuffer);
   if (std::error_code EC = BinOrErr.getError())
     return EC;
@@ -491,7 +478,7 @@ static std::error_code loadBinaryFormat(MemoryBufferRef ObjectBuffer,
   // Get the contents of the given sections.
   if (std::error_code EC = CoverageSection->getContents(CoverageMapping))
     return EC;
-  if (std::error_code EC = ProfileNames.load(*NamesSection))
+  if (std::error_code EC = ProfileNames.create(*NamesSection))
     return EC;
 
   return std::error_code();
@@ -502,33 +489,33 @@ BinaryCoverageReader::create(std::unique_ptr<MemoryBuffer> &ObjectBuffer,
                              StringRef Arch) {
   std::unique_ptr<BinaryCoverageReader> Reader(new BinaryCoverageReader());
 
-  SectionData Profile;
+  InstrProfSymtab ProfileNames;
   StringRef Coverage;
   uint8_t BytesInAddress;
   support::endianness Endian;
   std::error_code EC;
   if (ObjectBuffer->getBuffer().startswith(TestingFormatMagic))
     // This is a special format used for testing.
-    EC = loadTestingFormat(ObjectBuffer->getBuffer(), Profile, Coverage,
+    EC = loadTestingFormat(ObjectBuffer->getBuffer(), ProfileNames, Coverage,
                            BytesInAddress, Endian);
   else
-    EC = loadBinaryFormat(ObjectBuffer->getMemBufferRef(), Profile, Coverage,
-                          BytesInAddress, Endian, Arch);
+    EC = loadBinaryFormat(ObjectBuffer->getMemBufferRef(), ProfileNames,
+                          Coverage, BytesInAddress, Endian, Arch);
   if (EC)
     return EC;
 
   if (BytesInAddress == 4 && Endian == support::endianness::little)
     EC = readCoverageMappingData<uint32_t, support::endianness::little>(
-        Profile, Coverage, Reader->MappingRecords, Reader->Filenames);
+        ProfileNames, Coverage, Reader->MappingRecords, Reader->Filenames);
   else if (BytesInAddress == 4 && Endian == support::endianness::big)
     EC = readCoverageMappingData<uint32_t, support::endianness::big>(
-        Profile, Coverage, Reader->MappingRecords, Reader->Filenames);
+        ProfileNames, Coverage, Reader->MappingRecords, Reader->Filenames);
   else if (BytesInAddress == 8 && Endian == support::endianness::little)
     EC = readCoverageMappingData<uint64_t, support::endianness::little>(
-        Profile, Coverage, Reader->MappingRecords, Reader->Filenames);
+        ProfileNames, Coverage, Reader->MappingRecords, Reader->Filenames);
   else if (BytesInAddress == 8 && Endian == support::endianness::big)
     EC = readCoverageMappingData<uint64_t, support::endianness::big>(
-        Profile, Coverage, Reader->MappingRecords, Reader->Filenames);
+        ProfileNames, Coverage, Reader->MappingRecords, Reader->Filenames);
   else
     return coveragemap_error::malformed;
   if (EC)