Index: lib/profile/CMakeLists.txt
===================================================================
--- lib/profile/CMakeLists.txt
+++ lib/profile/CMakeLists.txt
@@ -1,3 +1,4 @@
+include_directories(..)
 
 CHECK_CXX_SOURCE_COMPILES("
 #ifdef _MSC_VER
@@ -50,6 +51,7 @@
 
 set(PROFILE_SOURCES
   GCDAProfiling.c
+  GCDAProfilingInterceptors.cc
   InstrProfiling.c
   InstrProfilingValue.c
   InstrProfilingBuffer.c
@@ -65,6 +67,7 @@
   InstrProfilingUtil.c)
 
 set(PROFILE_HEADERS
+  GCDAProfiling.h
   InstrProfData.inc
   InstrProfiling.h
   InstrProfilingInternal.h
@@ -110,6 +113,7 @@
     STATIC
     OS ${PROFILE_SUPPORTED_OS}
     ARCHS ${PROFILE_SUPPORTED_ARCH}
+    OBJECT_LIBS RTInterception
     CFLAGS ${EXTRA_FLAGS}
     SOURCES ${PROFILE_SOURCES}
     ADDITIONAL_HEADERS ${PROFILE_HEADERS}
@@ -118,6 +122,7 @@
   add_compiler_rt_runtime(clang_rt.profile
     STATIC
     ARCHS ${PROFILE_SUPPORTED_ARCH}
+    OBJECT_LIBS RTInterception
     CFLAGS ${EXTRA_FLAGS}
     SOURCES ${PROFILE_SOURCES}
     ADDITIONAL_HEADERS ${PROFILE_HEADERS}
Index: lib/profile/GCDAProfiling.h
===================================================================
--- lib/profile/GCDAProfiling.h
+++ lib/profile/GCDAProfiling.h
@@ -0,0 +1,16 @@
+/*===- GCDAProfiling.h ----------------------------------------------------===*\
+|*
+|*                     The LLVM Compiler Infrastructure
+|*
+|* This file is distributed under the University of Illinois Open Source
+|* License. See LICENSE.TXT for details.
+|*
+\*===----------------------------------------------------------------------===*/
+
+#ifndef PROFILE_INSTRPROFILING_GCDAPROFILING_H
+#define PROFILE_INSTRPROFILING_GCDAPROFILING_H
+
+void gcov_initialize_interceptors();
+void __gcov_flush();
+
+#endif /* PROFILE_INSTRPROFILING_GCDAPROFILING_H */
Index: lib/profile/GCDAProfiling.c
===================================================================
--- lib/profile/GCDAProfiling.c
+++ lib/profile/GCDAProfiling.c
@@ -26,6 +26,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "GCDAProfiling.h"
 #if defined(_WIN32)
 #include "WindowsMMap.h"
 #else
@@ -587,6 +588,8 @@
 void llvm_gcov_init(fn_ptr wfn, fn_ptr ffn) {
   static int atexit_ran = 0;
 
+  gcov_initialize_interceptors();
+
   if (wfn)
     llvm_register_writeout_function(wfn);
 
Index: lib/profile/GCDAProfilingInterceptors.cc
===================================================================
--- lib/profile/GCDAProfilingInterceptors.cc
+++ lib/profile/GCDAProfilingInterceptors.cc
@@ -0,0 +1,33 @@
+//===-- GCDAProfilingInterceptors.c ---------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "interception/interception.h"
+extern "C" {
+#include "GCDAProfiling.h"
+}
+
+#include <stdio.h>
+
+// Before forking, we should flush the counters so that the execution so far is
+// not counted twice.
+INTERCEPTOR(int, fork, void) {
+  __gcov_flush();
+  return REAL(fork)();
+}
+
+extern "C" void gcov_initialize_interceptors() {
+  static int inited = 0;
+  if (inited != 0) {
+    fprintf(stderr, "llvmgcda: Interceptors already initialized\n");
+  }
+
+  INTERCEPT_FUNCTION(fork);
+
+  inited = 1;
+}
Index: test/profile/Inputs/instrprof-gcov-fork.c
===================================================================
--- test/profile/Inputs/instrprof-gcov-fork.c
+++ test/profile/Inputs/instrprof-gcov-fork.c
@@ -0,0 +1,15 @@
+#include <unistd.h>
+
+void func1() {}
+void func2() {}
+
+int main(void)
+{
+  func1();
+
+  fork();
+
+  func2();
+
+  return 0;
+}
Index: test/profile/Inputs/instrprof-gcov-fork.c.gcov
===================================================================
--- test/profile/Inputs/instrprof-gcov-fork.c.gcov
+++ test/profile/Inputs/instrprof-gcov-fork.c.gcov
@@ -0,0 +1,23 @@
+// CHECK:        -:    0:Source:{{.*}}Inputs/instrprof-gcov-fork.c
+// CHECK-NEXT:        -:    0:Graph:instrprof-gcov-fork.gcno
+// CHECK-NEXT:        -:    0:Data:instrprof-gcov-fork.gcda
+// CHECK-NEXT:        -:    0:Runs:1
+// CHECK-NEXT:        -:    0:Programs:1
+// CHECK-NEXT:        -:    1:#include <unistd.h>
+// CHECK-NEXT:        -:    2:
+// CHECK-NEXT:function func1 called 1 returned 100% blocks executed 100%
+// CHECK-NEXT:        2:    3:void func1() {}
+// CHECK-NEXT:function func2 called 2 returned 100% blocks executed 100%
+// CHECK-NEXT:        4:    4:void func2() {}
+// CHECK-NEXT:        -:    5:
+// CHECK-NEXT:function main called 1 returned 100% blocks executed 100%
+// CHECK-NEXT:        -:    6:int main(void)
+// CHECK-NEXT:        -:    7:{
+// CHECK-NEXT:        1:    8:  func1();
+// CHECK-NEXT:        -:    9:
+// CHECK-NEXT:        1:   10:  fork();
+// CHECK-NEXT:        -:   11:
+// CHECK-NEXT:        1:   12:  func2();
+// CHECK-NEXT:        -:   13:
+// CHECK-NEXT:        1:   14:  return 0;
+// CHECK-NEXT:        -:   15:}
Index: test/profile/Posix/instrprof-gcov-fork.test
===================================================================
--- test/profile/Posix/instrprof-gcov-fork.test
+++ test/profile/Posix/instrprof-gcov-fork.test
@@ -0,0 +1,10 @@
+RUN: mkdir -p %t.d
+RUN: cd %t.d
+
+RUN: %clang --coverage -o %t %S/../Inputs/instrprof-gcov-fork.c
+RUN: test -f instrprof-gcov-fork.gcno
+
+RUN: rm -f instrprof-gcov-fork.gcda
+RUN: %run %t
+RUN: llvm-cov gcov -b -c instrprof-gcov-fork.gcda
+RUN: FileCheck --match-full-lines --strict-whitespace --input-file instrprof-gcov-fork.c.gcov %S/../Inputs/instrprof-gcov-fork.c.gcov