diff --git a/include/llvm/Support/GCOV.h b/include/llvm/Support/GCOV.h
index 6111d3aebec..188c4126f1f 100644
--- a/include/llvm/Support/GCOV.h
+++ b/include/llvm/Support/GCOV.h
@@ -250,6 +250,7 @@ public:
 private:
   GCOVFile &Parent;
   uint32_t Ident;
+  uint32_t Checksum;
   uint32_t LineNumber;
   StringRef Name;
   StringRef Filename;
diff --git a/lib/IR/GCOV.cpp b/lib/IR/GCOV.cpp
index 64d53e4251a..14eb71f0300 100644
--- a/lib/IR/GCOV.cpp
+++ b/lib/IR/GCOV.cpp
@@ -125,7 +125,7 @@ bool GCOVFunction::readGCNO(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
   uint32_t Dummy;
   if (!Buff.readInt(Dummy)) return false; // Function header length
   if (!Buff.readInt(Ident)) return false;
-  if (!Buff.readInt(Dummy)) return false; // Checksum #1
+  if (!Buff.readInt(Checksum)) return false;
   if (Version != GCOV::V402) {
     uint32_t CfgChecksum;
     if (!Buff.readInt(CfgChecksum)) return false;
@@ -212,6 +212,7 @@ bool GCOVFunction::readGCNO(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
 bool GCOVFunction::readGCDA(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
   uint32_t Dummy;
   if (!Buff.readInt(Dummy)) return false; // Function header length
+
   uint32_t GCDAIdent;
   if (!Buff.readInt(GCDAIdent)) return false;
   if (Ident != GCDAIdent) {
@@ -220,8 +221,13 @@ bool GCOVFunction::readGCDA(GCOVBuffer &Buff, GCOV::GCOVVersion Version) {
     return false;
   }
 
-  if (!Buff.readInt(Dummy)) return false; // Checksum #1
-
+  uint32_t GCDAChecksum;
+  if (!Buff.readInt(GCDAChecksum)) return false;
+  if (Checksum != GCDAChecksum) {
+    errs() << "Function checksums do not match: " << Checksum << " != "
+           << GCDAChecksum << " (in " << Name << ").\n";
+    return false;
+  }
 
   uint32_t CfgChecksum;
   if (Version != GCOV::V402) {
diff --git a/lib/Transforms/Instrumentation/GCOVProfiling.cpp b/lib/Transforms/Instrumentation/GCOVProfiling.cpp
index fb5bee2ede2..488f451944b 100644
--- a/lib/Transforms/Instrumentation/GCOVProfiling.cpp
+++ b/lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -314,12 +314,18 @@ namespace {
       this->os = os;
 
       Function *F = SP.getFunction();
-      DEBUG(dbgs() << "Function: " << F->getName() << "\n");
+      DEBUG(dbgs() << "Function: " << getFunctionName(SP) << "\n");
       uint32_t i = 0;
       for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
         Blocks[BB] = new GCOVBlock(i++, os);
       }
       ReturnBlock = new GCOVBlock(i++, os);
+
+      std::string FunctionNameAndLine;
+      raw_string_ostream FNLOS(FunctionNameAndLine);
+      FNLOS << getFunctionName(SP) << SP.getLineNumber();
+      FNLOS.flush();
+      FuncChecksum = hash_value(FunctionNameAndLine);
     }
 
     ~GCOVFunction() {
@@ -347,6 +353,10 @@ namespace {
       return EdgeDestinations;
     }
 
+    uint32_t getFuncChecksum() {
+      return FuncChecksum;
+    }
+
     void setCfgChecksum(uint32_t Checksum) {
       CfgChecksum = Checksum;
     }
@@ -359,7 +369,7 @@ namespace {
         ++BlockLen;
       write(BlockLen);
       write(Ident);
-      write(0);  // lineno checksum
+      write(FuncChecksum);
       if (UseCfgChecksum)
         write(CfgChecksum);
       writeGCOVString(getFunctionName(SP));
@@ -401,6 +411,7 @@ namespace {
    private:
     DISubprogram SP;
     uint32_t Ident;
+    uint32_t FuncChecksum;
     bool UseCfgChecksum;
     uint32_t CfgChecksum;
     DenseMap<BasicBlock *, GCOVBlock *> Blocks;
@@ -731,6 +742,7 @@ Constant *GCOVProfiler::getEmitFunctionFunc() {
   Type *Args[] = {
     Type::getInt32Ty(*Ctx),    // uint32_t ident
     Type::getInt8PtrTy(*Ctx),  // const char *function_name
+    Type::getInt32Ty(*Ctx),    // uint32_t func_checksum
     Type::getInt8Ty(*Ctx),     // uint8_t use_extra_checksum
     Type::getInt32Ty(*Ctx),    // uint32_t cfg_checksum
   };
@@ -813,11 +825,12 @@ Function *GCOVProfiler::insertCounterWriteout(
                           Builder.getInt32(CfgChecksum));
       for (unsigned j = 0, e = CountersBySP.size(); j != e; ++j) {
         DISubprogram SP(CountersBySP[j].second);
-        Builder.CreateCall4(
+        Builder.CreateCall5(
             EmitFunction, Builder.getInt32(j),
             Options.FunctionNamesInData ?
               Builder.CreateGlobalStringPtr(getFunctionName(SP)) :
               Constant::getNullValue(Builder.getInt8PtrTy()),
+            Builder.getInt32(Funcs[j]->getFuncChecksum()),
             Builder.getInt8(Options.UseCfgChecksum),
             Builder.getInt32(CfgChecksum));
 
diff --git a/test/tools/llvm-cov/Inputs/test.gcda b/test/tools/llvm-cov/Inputs/test.gcda
index a62c069c9a7..c0c8329afb6 100644
Binary files a/test/tools/llvm-cov/Inputs/test.gcda and b/test/tools/llvm-cov/Inputs/test.gcda differ
diff --git a/test/tools/llvm-cov/Inputs/test.gcno b/test/tools/llvm-cov/Inputs/test.gcno
index 218398548ef..97b67bb692b 100644
Binary files a/test/tools/llvm-cov/Inputs/test.gcno and b/test/tools/llvm-cov/Inputs/test.gcno differ
diff --git a/test/tools/llvm-cov/Inputs/test_checksum_mismatch.gcda b/test/tools/llvm-cov/Inputs/test_checksum_mismatch.gcda
deleted file mode 100644
index 2fcf33dd21b..00000000000
Binary files a/test/tools/llvm-cov/Inputs/test_checksum_mismatch.gcda and /dev/null differ
diff --git a/test/tools/llvm-cov/Inputs/test_file_checksum_fail.gcda b/test/tools/llvm-cov/Inputs/test_file_checksum_fail.gcda
new file mode 100644
index 00000000000..8bfd82c7b24
Binary files /dev/null and b/test/tools/llvm-cov/Inputs/test_file_checksum_fail.gcda differ
diff --git a/test/tools/llvm-cov/Inputs/test_func_checksum_fail.gcda b/test/tools/llvm-cov/Inputs/test_func_checksum_fail.gcda
new file mode 100644
index 00000000000..4c729a850d8
Binary files /dev/null and b/test/tools/llvm-cov/Inputs/test_func_checksum_fail.gcda differ
diff --git a/test/tools/llvm-cov/Inputs/test_read_fail.gcno b/test/tools/llvm-cov/Inputs/test_read_fail.gcno
index bcc20a65eee..88073f15dac 100644
Binary files a/test/tools/llvm-cov/Inputs/test_read_fail.gcno and b/test/tools/llvm-cov/Inputs/test_read_fail.gcno differ
diff --git a/test/tools/llvm-cov/llvm-cov.test b/test/tools/llvm-cov/llvm-cov.test
index e2a21e1889e..b08b514a9f2 100644
--- a/test/tools/llvm-cov/llvm-cov.test
+++ b/test/tools/llvm-cov/llvm-cov.test
@@ -11,6 +11,8 @@ RUN: rm test.cpp.llcov
 
 RUN: not llvm-cov -gcno=test_read_fail.gcno -gcda=test.gcda
 
-RUN: not llvm-cov -gcno=test.gcno -gcda=test_checksum_mismatch.gcda
+RUN: not llvm-cov -gcno=test.gcno -gcda=test_file_checksum_fail.gcda
+
+RUN: not llvm-cov -gcno=test.gcno -gcda=test_func_checksum_fail.gcda
 
 XFAIL: powerpc64, s390x, mips