[PGO] Make indexed value profile data more compact

- Make indexed value profile data more compact by peeling out 
  the per-site value count field into its own smaller sized array.
- Introduced formal data structure definitions to specify value 
  profile data layout in indexed format. Previously the layout 
  of the data is only assumed in the client code (scattered in 
  three different places : size computation, EmitData, and ReadData
- The new data structure  serves as a central place for layout documentation.
- Add interfaces to force BE output for value profile data (testing purpose)
- Add byte swap unit tests

Differential Revision: http://reviews.llvm.org/D14401

llvm-svn: 252563

1 files changed, 6 insertions, 41 deletions

diff --git a/llvm/lib/ProfileData/InstrProfReader.cpp b/llvm/lib/ProfileData/InstrProfReader.cpp
index 66fd961..b968e6b 100644
--- a/llvm/lib/ProfileData/InstrProfReader.cpp
+++ b/llvm/lib/ProfileData/InstrProfReader.cpp
@@ -298,51 +298,16 @@ typedef InstrProfLookupTrait::offset_type offset_type;
 
 bool InstrProfLookupTrait::ReadValueProfilingData(
     const unsigned char *&D, const unsigned char *const End) {
+  ErrorOr<std::unique_ptr<IndexedInstrProf::ValueProfData>> VDataPtrOrErr =
+      IndexedInstrProf::ValueProfData::getValueProfData(
+          D, End, ValueProfDataEndianness);
 
-  using namespace support;
-  // Read number of value kinds with value sites.
-  if (D + sizeof(uint64_t) > End)
+  if (VDataPtrOrErr.getError())
     return false;
-  uint64_t ValueKindCount = endian::readNext<uint64_t, little, unaligned>(D);
-
-  InstrProfRecord &ProfRecord = DataBuffer.back();
-  for (uint32_t Kind = 0; Kind < ValueKindCount; ++Kind) {
-
-    // Read value kind and number of value sites for kind.
-    if (D + 2 * sizeof(uint64_t) > End)
-      return false;
-
-    uint64_t ValueKind = endian::readNext<uint64_t, little, unaligned>(D);
-    uint64_t ValueSiteCount = endian::readNext<uint64_t, little, unaligned>(D);
 
-    ProfRecord.reserveSites(ValueKind, ValueSiteCount);
+  VDataPtrOrErr.get()->deserializeTo(DataBuffer.back(), &HashKeys);
+  D += VDataPtrOrErr.get()->TotalSize;
 
-    for (uint64_t VSite = 0; VSite < ValueSiteCount; ++VSite) {
-      // Read number of value data pairs at value site.
-      if (D + sizeof(uint64_t) > End)
-        return false;
-
-      uint64_t ValueDataCount =
-          endian::readNext<uint64_t, little, unaligned>(D);
-
-      // Check if there are as many ValueDataPairs as ValueDataCount in memory.
-      if (D + (ValueDataCount << 1) * sizeof(uint64_t) > End)
-        return false;
-
-      std::unique_ptr<InstrProfValueData[]> VDataPtr(
-          ValueDataCount == 0 ? nullptr
-                              : new InstrProfValueData[ValueDataCount]);
-
-      for (uint64_t VCount = 0; VCount < ValueDataCount; ++VCount) {
-        VDataPtr[VCount].Value =
-            endian::readNext<uint64_t, little, unaligned>(D);
-        VDataPtr[VCount].Count =
-            endian::readNext<uint64_t, little, unaligned>(D);
-      }
-      ProfRecord.addValueData(ValueKind, VSite, VDataPtr.get(), ValueDataCount,
-                              &HashKeys);
-    }
-  }
   return true;
 }