Profile: Add a library for the instrumentation based profiling format

This provides a library to work with the instrumentation based
profiling format that is used by clang's -fprofile-instr-* options and
by the llvm-profdata tool. This is a binary format, rather than the
textual one that's currently in use.

The tests are in the subsequent commits that use this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203703 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Profile/ProfileDataWriter.cpp

@@ -0,0 +1,71 @@
+//=-- ProfileDataWriter.cpp - Instrumented profiling writer -----------------=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains support for writing profiling data for clang's
+// instrumentation based PGO and coverage.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Profile/ProfileDataWriter.h"
+#include "llvm/Profile/ProfileData.h"
+#include "llvm/Support/Endian.h"
+
+using namespace llvm;
+
+template <typename T>
+struct LEBytes {
+  const T &Data;
+  LEBytes(const T &Data) : Data(Data) {}
+  void print(raw_ostream &OS) const {
+    for (uint32_t Shift = 0; Shift < sizeof(Data); ++Shift)
+      OS << (char)((Data >> (8 * Shift)) & 0xFF);
+  }
+};
+template <typename T>
+static raw_ostream &operator<<(raw_ostream &OS, const LEBytes<T> &Bytes) {
+  Bytes.print(OS);
+  return OS;
+}
+
+void ProfileDataWriter::addFunctionCounts(StringRef FuncName,
+                                          uint64_t FunctionHash,
+                                          uint64_t NumCounters,
+                                          const uint64_t *Counters) {
+  DataStart += 2 * sizeof(uint32_t) + FuncName.size();
+  FunctionOffsets[FuncName] = FunctionData.size() * sizeof(uint64_t);
+  FunctionData.push_back(FunctionHash);
+  FunctionData.push_back(NumCounters);
+  assert(NumCounters > 0 && "Function call counter missing!");
+  if (Counters[0] > MaxFunctionCount)
+    MaxFunctionCount = Counters[0];
+  for (uint64_t I = 0; I < NumCounters; ++I)
+    FunctionData.push_back(Counters[I]);
+}
+
+void ProfileDataWriter::write(raw_ostream &OS) {
+  for (char C : PROFILEDATA_MAGIC)
+    OS << C;
+  OS << LEBytes<uint32_t>(PROFILEDATA_VERSION);
+  OS << LEBytes<uint32_t>(DataStart);
+  OS << LEBytes<uint32_t>(0);
+  OS << LEBytes<uint64_t>(MaxFunctionCount);
+
+  for (const auto &I : FunctionOffsets) {
+    StringRef Name = I.getKey();
+    OS << LEBytes<uint32_t>(Name.size());
+    OS << Name;
+    OS << LEBytes<uint32_t>(I.getValue());
+  }
+
+  for (unsigned I = 0; I < sizeof(uint64_t) - DataStart % sizeof(uint64_t); ++I)
+    OS << '\0';
+
+  for (uint64_t Value : FunctionData)
+    OS << LEBytes<uint64_t>(Value);
+}