InstrProf: When reading, copy the data instead of taking a reference. NFC

This consolidates the logic to read instrprof records into the on disk
hash table's lookup trait and makes us copy the counter data instead
of taking references to it as we read. This will simplify further
changes to the format.

Patch by Betul Buyukkurt.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240206 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ProfileData/InstrProf.h

@@ -16,7 +16,9 @@
 #ifndef LLVM_PROFILEDATA_INSTRPROF_H_
 #define LLVM_PROFILEDATA_INSTRPROF_H_
 
+#include "llvm/ADT/StringRef.h"
 #include <system_error>
+#include <vector>
 
 namespace llvm {
 const std::error_category &instrprof_category();
@@ -41,6 +43,16 @@ inline std::error_code make_error_code(instrprof_error E) {
   return std::error_code(static_cast<int>(E), instrprof_category());
 }
 
+/// Profiling information for a single function.
+struct InstrProfRecord {
+  InstrProfRecord() {}
+  InstrProfRecord(StringRef Name, uint64_t Hash, std::vector<uint64_t> &Counts)
+      : Name(Name), Hash(Hash), Counts(std::move(Counts)) {}
+  StringRef Name;
+  uint64_t Hash;
+  std::vector<uint64_t> Counts;
+};
+
 } // end namespace llvm
 
 namespace std {

include/llvm/ProfileData/InstrProfReader.h

@@ -29,16 +29,6 @@ namespace llvm {
 
 class InstrProfReader;
 
-/// Profiling information for a single function.
-struct InstrProfRecord {
-  InstrProfRecord() {}
-  InstrProfRecord(StringRef Name, uint64_t Hash, ArrayRef<uint64_t> Counts)
-      : Name(Name), Hash(Hash), Counts(Counts) {}
-  StringRef Name;
-  uint64_t Hash;
-  ArrayRef<uint64_t> Counts;
-};
-
 /// A file format agnostic iterator over profiling data.
 class InstrProfIterator : public std::iterator<std::input_iterator_tag,
                                                InstrProfRecord> {
@@ -114,8 +104,6 @@ private:
   std::unique_ptr<MemoryBuffer> DataBuffer;
   /// Iterator over the profile data.
   line_iterator Line;
-  /// The current set of counter values.
-  std::vector<uint64_t> Counts;
 
   TextInstrProfReader(const TextInstrProfReader &) = delete;
   TextInstrProfReader &operator=(const TextInstrProfReader &) = delete;
@@ -141,8 +129,6 @@ class RawInstrProfReader : public InstrProfReader {
 private:
   /// The profile data file contents.
   std::unique_ptr<MemoryBuffer> DataBuffer;
-  /// The current set of counter values.
-  std::vector<uint64_t> Counts;
   struct ProfileData {
     const uint32_t NameSize;
     const uint32_t NumCounters;
@@ -206,17 +192,16 @@ enum class HashT : uint32_t;
 /// Trait for lookups into the on-disk hash table for the binary instrprof
 /// format.
 class InstrProfLookupTrait {
-  std::vector<uint64_t> DataBuffer;
+  std::vector<InstrProfRecord> DataBuffer;
   IndexedInstrProf::HashT HashType;
-public:
+  unsigned FormatVersion;
-  InstrProfLookupTrait(IndexedInstrProf::HashT HashType) : HashType(HashType) {}
+
+public:
+  InstrProfLookupTrait(IndexedInstrProf::HashT HashType, unsigned FormatVersion)
+      : HashType(HashType), FormatVersion(FormatVersion) {}
+
+  typedef ArrayRef<InstrProfRecord> data_type;
 
-  struct data_type {
-    data_type(StringRef Name, ArrayRef<uint64_t> Data)
-        : Name(Name), Data(Data) {}
-    StringRef Name;
-    ArrayRef<uint64_t> Data;
-  };
   typedef StringRef internal_key_type;
   typedef StringRef external_key_type;
   typedef uint64_t hash_value_type;
@@ -239,22 +224,9 @@ public:
     return StringRef((const char *)D, N);
   }
 
-  data_type ReadData(StringRef K, const unsigned char *D, offset_type N) {
+  data_type ReadData(StringRef K, const unsigned char *D, offset_type N);
-    DataBuffer.clear();
-    if (N % sizeof(uint64_t))
-      // The data is corrupt, don't try to read it.
-      return data_type("", DataBuffer);
-
-    using namespace support;
-    // We just treat the data as opaque here. It's simpler to handle in
-    // IndexedInstrProfReader.
-    unsigned NumEntries = N / sizeof(uint64_t);
-    DataBuffer.reserve(NumEntries);
-    for (unsigned I = 0; I < NumEntries; ++I)
-      DataBuffer.push_back(endian::readNext<uint64_t, little, unaligned>(D));
-    return data_type(K, DataBuffer);
-  }
 };
+
 typedef OnDiskIterableChainedHashTable<InstrProfLookupTrait>
     InstrProfReaderIndex;
 
@@ -267,8 +239,6 @@ private:
   std::unique_ptr<InstrProfReaderIndex> Index;
   /// Iterator over the profile data.
   InstrProfReaderIndex::data_iterator RecordIterator;
-  /// Offset into our current data set.
-  size_t CurrentOffset;
   /// The file format version of the profile data.
   uint64_t FormatVersion;
   /// The maximal execution count among all functions.
@@ -278,7 +248,7 @@ private:
   IndexedInstrProfReader &operator=(const IndexedInstrProfReader &) = delete;
 public:
   IndexedInstrProfReader(std::unique_ptr<MemoryBuffer> DataBuffer)
-      : DataBuffer(std::move(DataBuffer)), Index(nullptr), CurrentOffset(0) {}
+      : DataBuffer(std::move(DataBuffer)), Index(nullptr) {}
 
   /// Return true if the given buffer is in an indexed instrprof format.
   static bool hasFormat(const MemoryBuffer &DataBuffer);

lib/ProfileData/InstrProfReader.cpp

@@ -15,7 +15,6 @@
 #include "llvm/ProfileData/InstrProfReader.h"
 #include "InstrProfIndexed.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/ProfileData/InstrProf.h"
 #include <cassert>
 
 using namespace llvm;
@@ -126,18 +125,16 @@ std::error_code TextInstrProfReader::readNextRecord(InstrProfRecord &Record) {
     return error(instrprof_error::malformed);
 
   // Read each counter and fill our internal storage with the values.
-  Counts.clear();
+  Record.Counts.clear();
-  Counts.reserve(NumCounters);
+  Record.Counts.reserve(NumCounters);
   for (uint64_t I = 0; I < NumCounters; ++I) {
     if (Line.is_at_end())
       return error(instrprof_error::truncated);
     uint64_t Count;
     if ((Line++)->getAsInteger(10, Count))
       return error(instrprof_error::malformed);
-    Counts.push_back(Count);
+    Record.Counts.push_back(Count);
   }
-  // Give the record a reference to our internal counter storage.
-  Record.Counts = Counts;
 
   return success();
 }
@@ -280,11 +277,10 @@ RawInstrProfReader<IntPtrT>::readNextRecord(InstrProfRecord &Record) {
   Record.Hash = swap(Data->FuncHash);
   Record.Name = RawName;
   if (ShouldSwapBytes) {
-    Counts.clear();
+    Record.Counts.clear();
-    Counts.reserve(RawCounts.size());
+    Record.Counts.reserve(RawCounts.size());
     for (uint64_t Count : RawCounts)
-      Counts.push_back(swap(Count));
+      Record.Counts.push_back(swap(Count));
-    Record.Counts = Counts;
   } else
     Record.Counts = RawCounts;
 
@@ -303,6 +299,49 @@ InstrProfLookupTrait::ComputeHash(StringRef K) {
   return IndexedInstrProf::ComputeHash(HashType, K);
 }
 
+typedef InstrProfLookupTrait::data_type data_type;
+typedef InstrProfLookupTrait::offset_type offset_type;
+
+data_type InstrProfLookupTrait::ReadData(StringRef K, const unsigned char *D,
+                                         offset_type N) {
+
+  // Check if the data is corrupt. If so, don't try to read it.
+  if (N % sizeof(uint64_t))
+    return data_type();
+
+  DataBuffer.clear();
+  uint64_t NumCounts;
+  uint64_t NumEntries = N / sizeof(uint64_t);
+  std::vector<uint64_t> CounterBuffer;
+  for (uint64_t I = 0; I < NumEntries; I += NumCounts) {
+    using namespace support;
+    // The function hash comes first.
+    uint64_t Hash = endian::readNext<uint64_t, little, unaligned>(D);
+
+    if (++I >= NumEntries)
+      return data_type();
+
+    // In v1, we have at least one count.
+    // Later, we have the number of counts.
+    NumCounts = (1 == FormatVersion)
+                    ? NumEntries - I
+                    : endian::readNext<uint64_t, little, unaligned>(D);
+    if (1 != FormatVersion)
+      ++I;
+
+    // If we have more counts than data, this is bogus.
+    if (I + NumCounts > NumEntries)
+      return data_type();
+
+    CounterBuffer.clear();
+    for (unsigned J = 0; J < NumCounts; ++J)
+      CounterBuffer.push_back(endian::readNext<uint64_t, little, unaligned>(D));
+
+    DataBuffer.push_back(InstrProfRecord(K, Hash, CounterBuffer));
+  }
+  return DataBuffer;
+}
+
 bool IndexedInstrProfReader::hasFormat(const MemoryBuffer &DataBuffer) {
   if (DataBuffer.getBufferSize() < 8)
     return false;
@@ -342,8 +381,9 @@ std::error_code IndexedInstrProfReader::readHeader() {
   uint64_t HashOffset = endian::readNext<uint64_t, little, unaligned>(Cur);
 
   // The rest of the file is an on disk hash table.
-  Index.reset(InstrProfReaderIndex::Create(Start + HashOffset, Cur, Start,
+  Index.reset(InstrProfReaderIndex::Create(
-                                           InstrProfLookupTrait(HashType)));
+      Start + HashOffset, Cur, Start,
+      InstrProfLookupTrait(HashType, FormatVersion)));
   // Set up our iterator for readNextRecord.
   RecordIterator = Index->data_begin();
 
@@ -357,21 +397,14 @@ std::error_code IndexedInstrProfReader::getFunctionCounts(
     return error(instrprof_error::unknown_function);
 
   // Found it. Look for counters with the right hash.
-  ArrayRef<uint64_t> Data = (*Iter).Data;
+  ArrayRef<InstrProfRecord> Data = (*Iter);
-  uint64_t NumCounts;
+  if (Data.empty())
-  for (uint64_t I = 0, E = Data.size(); I != E; I += NumCounts) {
-    // The function hash comes first.
-    uint64_t FoundHash = Data[I++];
-    // In v1, we have at least one count. Later, we have the number of counts.
-    if (I == E)
-      return error(instrprof_error::malformed);
-    NumCounts = FormatVersion == 1 ? E - I : Data[I++];
-    // If we have more counts than data, this is bogus.
-    if (I + NumCounts > E)
     return error(instrprof_error::malformed);
+
+  for (unsigned I = 0, E = Data.size(); I < E; ++I) {
     // Check for a match and fill the vector if there is one.
-    if (FoundHash == FuncHash) {
+    if (Data[I].Hash == FuncHash) {
-      Counts = Data.slice(I, NumCounts);
+      Counts = Data[I].Counts;
       return success();
     }
   }
@@ -384,30 +417,15 @@ IndexedInstrProfReader::readNextRecord(InstrProfRecord &Record) {
   if (RecordIterator == Index->data_end())
     return error(instrprof_error::eof);
 
-  // Record the current function name.
+  if ((*RecordIterator).empty())
-  Record.Name = (*RecordIterator).Name;
-
-  ArrayRef<uint64_t> Data = (*RecordIterator).Data;
-  // Valid data starts with a hash and either a count or the number of counts.
-  if (CurrentOffset + 1 > Data.size())
     return error(instrprof_error::malformed);
-  // First we have a function hash.
-  Record.Hash = Data[CurrentOffset++];
-  // In version 1 we knew the number of counters implicitly, but in newer
-  // versions we store the number of counters next.
-  uint64_t NumCounts =
-      FormatVersion == 1 ? Data.size() - CurrentOffset : Data[CurrentOffset++];
-  if (CurrentOffset + NumCounts > Data.size())
-    return error(instrprof_error::malformed);
-  // And finally the counts themselves.
-  Record.Counts = Data.slice(CurrentOffset, NumCounts);
 
-  // If we've exhausted this function's data, increment the record.
+  static unsigned RecordIndex = 0;
-  CurrentOffset += NumCounts;
+  ArrayRef<InstrProfRecord> Data = (*RecordIterator);
-  if (CurrentOffset == Data.size()) {
+  Record = Data[RecordIndex++];
+  if (RecordIndex >= Data.size()) {
     ++RecordIterator;
-    CurrentOffset = 0;
+    RecordIndex = 0;
   }
-
   return success();
 }