diff --git a/compiler-rt/include/CMakeLists.txt b/compiler-rt/include/CMakeLists.txt
--- a/compiler-rt/include/CMakeLists.txt
+++ b/compiler-rt/include/CMakeLists.txt
@@ -1,3 +1,6 @@
+set(GCOV_COMPAT_HEADERS
+  gcov.h)
+
 if (COMPILER_RT_BUILD_SANITIZERS)
   set(SANITIZER_HEADERS
     sanitizer/allocator_interface.h
@@ -25,6 +28,7 @@
 endif(COMPILER_RT_BUILD_XRAY)
 
 set(COMPILER_RT_HEADERS
+  ${GCOV_COMPAT_HEADERS}
   ${SANITIZER_HEADERS}
   ${XRAY_HEADERS})
 
@@ -46,6 +50,11 @@
 add_dependencies(compiler-rt compiler-rt-headers)
 set_target_properties(compiler-rt-headers PROPERTIES FOLDER "Compiler-RT Misc")
 
+# Install gcov compat headers.
+install(FILES ${GCOV_COMPAT_HEADERS}
+  PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
+  DESTINATION ${COMPILER_RT_INSTALL_PATH}/include)
+
 # Install sanitizer headers.
 install(FILES ${SANITIZER_HEADERS}
   COMPONENT compiler-rt-headers
diff --git a/compiler-rt/include/gcov.h b/compiler-rt/include/gcov.h
new file mode 100644
--- /dev/null
+++ b/compiler-rt/include/gcov.h
@@ -0,0 +1,23 @@
+//===-- gcov.h ------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides the public interface for functions which are available to
+// end-users when using gcov(3).
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef	COMPILER_RT_GCOV_H
+#define	COMPILER_RT_GCOV_H
+
+/*
+ * - Write profile information/counters out to their appropriate GCDA files.
+ * - Reset profile counters to zero.
+ */
+extern void __gcov_flush(void);
+
+#endif
diff --git a/compiler-rt/lib/profile/CMakeLists.txt b/compiler-rt/lib/profile/CMakeLists.txt
--- a/compiler-rt/lib/profile/CMakeLists.txt
+++ b/compiler-rt/lib/profile/CMakeLists.txt
@@ -74,6 +74,8 @@
   InstrProfilingUtil.h
   WindowsMMap.h)
 
+include_directories(../../include)
+
 if(WIN32)
     list(APPEND PROFILE_SOURCES WindowsMMap.c)
 endif()
diff --git a/compiler-rt/lib/profile/GCDAProfiling.c b/compiler-rt/lib/profile/GCDAProfiling.c
--- a/compiler-rt/lib/profile/GCDAProfiling.c
+++ b/compiler-rt/lib/profile/GCDAProfiling.c
@@ -46,6 +46,8 @@
 #include <stdint.h>
 #endif
 
+#include <gcov.h>
+
 #if defined(_MSC_VER)
 typedef unsigned char uint8_t;
 typedef unsigned int uint32_t;
@@ -619,7 +621,7 @@
   fn_list_insert(&flush_fn_list, fn);
 }
 
-void __gcov_flush() {
+void __gcov_flush(void) {
   struct fn_node* curr = flush_fn_list.head;
 
   while (curr) {
diff --git a/compiler-rt/test/profile/Inputs/instrprof-gcov-__gcov_flush-multiple.c b/compiler-rt/test/profile/Inputs/instrprof-gcov-__gcov_flush-multiple.c
--- a/compiler-rt/test/profile/Inputs/instrprof-gcov-__gcov_flush-multiple.c
+++ b/compiler-rt/test/profile/Inputs/instrprof-gcov-__gcov_flush-multiple.c
@@ -1,3 +1,6 @@
+#include <stdio.h>
+#include <gcov.h>
+
 int main(void) {
   __gcov_flush();
 
diff --git a/compiler-rt/test/profile/Inputs/instrprof-gcov-__gcov_flush-terminate.c b/compiler-rt/test/profile/Inputs/instrprof-gcov-__gcov_flush-terminate.c
--- a/compiler-rt/test/profile/Inputs/instrprof-gcov-__gcov_flush-terminate.c
+++ b/compiler-rt/test/profile/Inputs/instrprof-gcov-__gcov_flush-terminate.c
@@ -1,3 +1,5 @@
+#include <gcov.h>
+
 int main(void) {
   int i = 22;
 
diff --git a/compiler-rt/test/profile/Inputs/instrprof-shared-main-gcov-flush.c b/compiler-rt/test/profile/Inputs/instrprof-shared-main-gcov-flush.c
--- a/compiler-rt/test/profile/Inputs/instrprof-shared-main-gcov-flush.c
+++ b/compiler-rt/test/profile/Inputs/instrprof-shared-main-gcov-flush.c
@@ -1,5 +1,6 @@
+#include <gcov.h>
+
 extern void foo(int n);
-extern void __gcov_flush(void);
 
 int bar1 = 0;
 int bar2 = 1;