[Coverage] Refactor coverage mapping reader code /NFC

(Resubmit after fixing build bot failures)

In this refactoring, member functions are introduced to access
CovMap header/func record members and hide layout details. This
will enable further code restructuring to support reading multiple
versions of coverage mapping data with shared/templatized code. 
(When coveremap format version changes, backward compatibtility
should be preserved).

llvm-svn: 257551

llvm/include/llvm/ProfileData/CoverageMapping.h

@@ -20,13 +20,33 @@
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/iterator.h"
-#include "llvm/ProfileData/InstrProfData.inc"
+#include "llvm/ProfileData/InstrProf.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/Endian.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/raw_ostream.h"
 #include <system_error>
 #include <tuple>
 
+namespace llvm {
+namespace coverage {
+enum class coveragemap_error {
+  success = 0,
+  eof,
+  no_data_found,
+  unsupported_version,
+  truncated,
+  malformed
+};
+} // end of coverage namespace.
+}
+
+namespace std {
+template <>
+struct is_error_code_enum<llvm::coverage::coveragemap_error> : std::true_type {
+};
+}
+
 namespace llvm {
 class IndexedInstrProfReader;
 namespace coverage {
@@ -455,20 +475,10 @@ public:
 
 const std::error_category &coveragemap_category();
 
-enum class coveragemap_error {
-  success = 0,
-  eof,
-  no_data_found,
-  unsupported_version,
-  truncated,
-  malformed
-};
-
 inline std::error_code make_error_code(coveragemap_error E) {
   return std::error_code(static_cast<int>(E), coveragemap_category());
 }
 
-
 // Profile coverage map has the following layout:
 // [CoverageMapFileHeader]
 // [ArrayStart]
@@ -479,14 +489,50 @@ inline std::error_code make_error_code(coveragemap_error E) {
 // [Encoded Region Mapping Data]
 LLVM_PACKED_START
 template <class IntPtrT> struct CovMapFunctionRecord {
-  #define COVMAP_FUNC_RECORD(Type, LLVMType, Name, Init) Type Name;
-  #include "llvm/ProfileData/InstrProfData.inc"
+#define COVMAP_FUNC_RECORD(Type, LLVMType, Name, Init) Type Name;
+#include "llvm/ProfileData/InstrProfData.inc"
+
+  // Return the structural hash associated with the function.
+  template <support::endianness Endian> uint64_t getFuncHash() const {
+    return support::endian::byte_swap<uint64_t, Endian>(FuncHash);
+  }
+  // Return the coverage map data size for the funciton.
+  template <support::endianness Endian> uint32_t getDataSize() const {
+    return support::endian::byte_swap<uint32_t, Endian>(DataSize);
+  }
+  // Return function lookup key. The value is consider opaque.
+  template <support::endianness Endian> IntPtrT getFuncNameRef() const {
+    return support::endian::byte_swap<IntPtrT, Endian>(NamePtr);
+  }
+  // Return the PGO name of the function */
+  template <support::endianness Endian>
+  std::error_code getFuncName(InstrProfSymtab &ProfileNames,
+                              StringRef &FuncName) const {
+    IntPtrT NameRef = getFuncNameRef<Endian>();
+    uint32_t NameS = support::endian::byte_swap<IntPtrT, Endian>(NameSize);
+    FuncName = ProfileNames.getFuncName(NameRef, NameS);
+    if (NameS && FuncName.empty())
+      return coveragemap_error::malformed;
+    return std::error_code();
+  }
 };
 // Per module coverage mapping data header, i.e. CoverageMapFileHeader
 // documented above.
 struct CovMapHeader {
 #define COVMAP_HEADER(Type, LLVMType, Name, Init) Type Name;
 #include "llvm/ProfileData/InstrProfData.inc"
+  template <support::endianness Endian> uint32_t getNRecords() const {
+    return support::endian::byte_swap<uint32_t, Endian>(NRecords);
+  }
+  template <support::endianness Endian> uint32_t getFilenamesSize() const {
+    return support::endian::byte_swap<uint32_t, Endian>(FilenamesSize);
+  }
+  template <support::endianness Endian> uint32_t getCoverageSize() const {
+    return support::endian::byte_swap<uint32_t, Endian>(CoverageSize);
+  }
+  template <support::endianness Endian> uint32_t getVersion() const {
+    return support::endian::byte_swap<uint32_t, Endian>(Version);
+  }
 };
 
 LLVM_PACKED_END
@@ -529,10 +575,4 @@ template<> struct DenseMapInfo<coverage::CounterExpression> {
 
 } // end namespace llvm
 
-namespace std {
-template <>
-struct is_error_code_enum<llvm::coverage::coveragemap_error> : std::true_type {};
-}
-
-
 #endif // LLVM_PROFILEDATA_COVERAGEMAPPING_H_

llvm/lib/ProfileData/CoverageMappingReader.cpp

@@ -319,13 +319,10 @@ static std::error_code readCoverageMappingData(
     if (Buf + sizeof(CovMapHeader) > End)
       return coveragemap_error::malformed;
     auto CovHeader = reinterpret_cast<const coverage::CovMapHeader *>(Buf);
-    uint32_t NRecords =
-        endian::byte_swap<uint32_t, Endian>(CovHeader->NRecords);
-    uint32_t FilenamesSize =
-        endian::byte_swap<uint32_t, Endian>(CovHeader->FilenamesSize);
-    uint32_t CoverageSize =
-        endian::byte_swap<uint32_t, Endian>(CovHeader->CoverageSize);
-    uint32_t Version = endian::byte_swap<uint32_t, Endian>(CovHeader->Version);
+    uint32_t NRecords = CovHeader->getNRecords<Endian>();
+    uint32_t FilenamesSize = CovHeader->getFilenamesSize<Endian>();
+    uint32_t CoverageSize = CovHeader->getCoverageSize<Endian>();
+    uint32_t Version = CovHeader->getVersion<Endian>();
     Buf = reinterpret_cast<const char *>(++CovHeader);
 
     if (Version > coverage::CoverageMappingCurrentVersion)
@@ -360,11 +357,8 @@ static std::error_code readCoverageMappingData(
         reinterpret_cast<const coverage::CovMapFunctionRecord<T> *>(FunBuf);
     while ((const char *)CFR < FunEnd) {
       // Read the function information
-      T NamePtr = endian::byte_swap<T, Endian>(CFR->NamePtr);
-      uint32_t NameSize = endian::byte_swap<uint32_t, Endian>(CFR->NameSize);
-      uint32_t DataSize = endian::byte_swap<uint32_t, Endian>(CFR->DataSize);
-      uint64_t FuncHash = endian::byte_swap<uint64_t, Endian>(CFR->FuncHash);
-      CFR++;
+      uint32_t DataSize = CFR->template getDataSize<Endian>();
+      uint64_t FuncHash = CFR->template getFuncHash<Endian>();
 
       // Now use that to read the coverage data.
       if (CovBuf + DataSize > CovEnd)
@@ -375,16 +369,18 @@ static std::error_code readCoverageMappingData(
       // Ignore this record if we already have a record that points to the same
       // function name. This is useful to ignore the redundant records for the
       // functions with ODR linkage.
-      if (!UniqueFunctionMappingData.insert(NamePtr).second)
+      T NameRef = CFR->template getFuncNameRef<Endian>();
+      if (!UniqueFunctionMappingData.insert(NameRef).second)
         continue;
 
-      // Finally, grab the name and create a record.
-      StringRef FuncName = ProfileNames.getFuncName(NamePtr, NameSize);
-      if (NameSize && FuncName.empty())
-        return coveragemap_error::malformed;
+      StringRef FuncName;
+      if (std::error_code EC =
+              CFR->template getFuncName<Endian>(ProfileNames, FuncName))
+        return EC;
       Records.push_back(BinaryCoverageReader::ProfileMappingRecord(
           CoverageMappingVersion(Version), FuncName, FuncHash, Mapping,
           FilenamesBegin, Filenames.size() - FilenamesBegin));
+      CFR++;
     }
   }