3 files changed, 65 insertions, 0 deletions
diff --git a/lib/ProfileData/CMakeLists.txt b/lib/ProfileData/CMakeLists.txt
index cef3a5336b..5204afcdc4 100644
--- a/lib/ProfileData/CMakeLists.txt
+++ b/lib/ProfileData/CMakeLists.txt
@@ -1,6 +1,7 @@
 add_llvm_library(LLVMProfileData
   InstrProf.cpp
   InstrProfReader.cpp
+  InstrProfWriter.cpp
 
   LINK_LIBS
   LLVMSupport
diff --git a/lib/ProfileData/InstrProf.cpp b/lib/ProfileData/InstrProf.cpp
index 329abf84e6..ecabdd75bd 100644
--- a/lib/ProfileData/InstrProf.cpp
+++ b/lib/ProfileData/InstrProf.cpp
@@ -39,6 +39,12 @@ class InstrProfErrorCategoryType : public error_category {
       return "Malformed profile data";
     case instrprof_error::unknown_function:
       return "No profile data available for function";
+    case instrprof_error::hash_mismatch:
+      return "Function hash mismatch";
+    case instrprof_error::count_mismatch:
+      return "Function count mismatch";
+    case instrprof_error::counter_overflow:
+      return "Counter overflow";
     }
     llvm_unreachable("A value of instrprof_error has no message.");
   }
diff --git a/lib/ProfileData/InstrProfWriter.cpp b/lib/ProfileData/InstrProfWriter.cpp
new file mode 100644
index 0000000000..320860a4cb
--- /dev/null
+++ b/lib/ProfileData/InstrProfWriter.cpp
@@ -0,0 +1,58 @@
+//=-- InstrProfWriter.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/ProfileData/InstrProfWriter.h"
+#include "llvm/Support/Endian.h"
+
+using namespace llvm;
+
+error_code InstrProfWriter::addFunctionCounts(StringRef FunctionName,
+                                              uint64_t FunctionHash,
+                                              ArrayRef<uint64_t> Counters) {
+  auto Where = FunctionData.find(FunctionName);
+  if (Where == FunctionData.end()) {
+    // If this is the first time we've seen this function, just add it.
+    FunctionData[FunctionName] = {FunctionHash, Counters};
+    return instrprof_error::success;;
+  }
+
+  auto &Data = Where->getValue();
+  // We can only add to existing functions if they match, so we check the hash
+  // and number of counters.
+  if (Data.Hash != FunctionHash)
+    return instrprof_error::hash_mismatch;
+  if (Data.Counts.size() != Counters.size())
+    return instrprof_error::count_mismatch;
+  // These match, add up the counters.
+  for (size_t I = 0, E = Counters.size(); I < E; ++I) {
+    if (Data.Counts[I] + Counters[I] < Data.Counts[I])
+      return instrprof_error::counter_overflow;
+    Data.Counts[I] += Counters[I];
+  }
+  return instrprof_error::success;
+}
+
+void InstrProfWriter::write(raw_ostream &OS) {
+  // Write out the counts for each function.
+  for (const auto &I : FunctionData) {
+    StringRef Name = I.getKey();
+    uint64_t Hash = I.getValue().Hash;
+    const std::vector<uint64_t> &Counts = I.getValue().Counts;
+
+    OS << Name << "\n" << Hash << "\n" << Counts.size() << "\n";
+    for (uint64_t Count : Counts)
+      OS << Count << "\n";
+    OS << "\n";
+  }
+}