Index: cmake/config-ix.cmake
===================================================================
--- cmake/config-ix.cmake
+++ cmake/config-ix.cmake
@@ -532,7 +532,7 @@
 endif()
 
 if (PROFILE_SUPPORTED_ARCH AND NOT LLVM_USE_SANITIZER AND
-    OS_NAME MATCHES "Darwin|Linux|FreeBSD|Windows|Android")
+    OS_NAME MATCHES "Darwin|Linux|FreeBSD|Windows|Android|SunOS")
   set(COMPILER_RT_HAS_PROFILE TRUE)
 else()
   set(COMPILER_RT_HAS_PROFILE FALSE)
Index: lib/profile/GCDAProfiling.c
===================================================================
--- lib/profile/GCDAProfiling.c
+++ lib/profile/GCDAProfiling.c
@@ -34,9 +34,6 @@
 #else
 #include <sys/mman.h>
 #include <sys/file.h>
-#ifndef MAP_FILE
-#define MAP_FILE 0
-#endif
 #ifndef O_BINARY
 #define O_BINARY 0
 #endif
@@ -266,7 +263,7 @@
    * same GCDA. This can fail if the filesystem doesn't support it, but in that
    * case we'll just carry on with the old racy behaviour and hope for the best.
    */
-  flock(fd, LOCK_EX);
+  lprofLockFd(fd);
   output_file = fdopen(fd, mode);
 
   /* Initialize the write buffer. */
@@ -465,7 +462,7 @@
       unmap_file();
     }
 
-    flock(fd, LOCK_UN);
+    lprofUnlockFd(fd);
     fclose(output_file);
     output_file = NULL;
     write_buffer = NULL;
Index: lib/profile/InstrProfilingFile.c
===================================================================
--- lib/profile/InstrProfilingFile.c
+++ lib/profile/InstrProfilingFile.c
@@ -85,7 +85,6 @@
 COMPILER_RT_WEAK lprofFilename lprofCurFilename = {0, 0, 0, {0}, {0},
                                                    0, 0, 0, PNS_unknown};
 
-int getpid(void);
 static int getCurFilenameLength();
 static const char *getCurFilename(char *FilenameBuf);
 static unsigned doMerging() { return lprofCurFilename.MergePoolSize; }
Index: lib/profile/InstrProfilingPlatformLinux.c
===================================================================
--- lib/profile/InstrProfilingPlatformLinux.c
+++ lib/profile/InstrProfilingPlatformLinux.c
@@ -9,7 +9,7 @@
 
 #include "InstrProfiling.h"
 
-#if defined(__linux__) || defined(__FreeBSD__)
+#if defined(__linux__) || defined(__FreeBSD__) || (defined(__sun__) && defined(__svr4__))
 #include <stdlib.h>
 
 #define PROF_DATA_START INSTR_PROF_SECT_START(INSTR_PROF_DATA_SECT_NAME)
Index: lib/profile/InstrProfilingPlatformOther.c
===================================================================
--- lib/profile/InstrProfilingPlatformOther.c
+++ lib/profile/InstrProfilingPlatformOther.c
@@ -9,7 +9,7 @@
 
 #include "InstrProfiling.h"
 
-#if !defined(__APPLE__) && !defined(__linux__) && !defined(__FreeBSD__)
+#if !defined(__APPLE__) && !defined(__linux__) && !defined(__FreeBSD__) && !(defined(__sun__) && defined(__svr4__))
 
 #include <stdlib.h>
 
Index: lib/profile/InstrProfilingPort.h
===================================================================
--- lib/profile/InstrProfilingPort.h
+++ lib/profile/InstrProfilingPort.h
@@ -107,6 +107,10 @@
 #define PROF_NOTE(Format, ...)                                                 \
   fprintf(stderr, "LLVM Profile Note: " Format, __VA_ARGS__);
 
+#ifndef MAP_FILE
+#define MAP_FILE 0
+#endif
+
 #if defined(__FreeBSD__)
 
 #include <inttypes.h>
Index: lib/profile/InstrProfilingUtil.h
===================================================================
--- lib/profile/InstrProfilingUtil.h
+++ lib/profile/InstrProfilingUtil.h
@@ -16,6 +16,9 @@
 /*! \brief Create a directory tree. */
 void __llvm_profile_recursive_mkdir(char *Pathname);
 
+int lprofLockFd(int fd);
+int lprofUnlockFd(int fd);
+
 /*! Open file \c Filename for read+write with write
  * lock for exclusive access. The caller will block
  * if the lock is already held by another process. */
Index: lib/profile/InstrProfilingUtil.c
===================================================================
--- lib/profile/InstrProfilingUtil.c
+++ lib/profile/InstrProfilingUtil.c
@@ -93,9 +93,7 @@
 }
 #endif
 
-COMPILER_RT_VISIBILITY FILE *lprofOpenFileEx(const char *ProfileName) {
-  FILE *f;
-  int fd;
+COMPILER_RT_VISIBILITY int lprofLockFd(int fd) {
 #ifdef COMPILER_RT_HAS_FCNTL_LCK
   struct flock s_flock;
 
@@ -103,21 +101,59 @@
   s_flock.l_start = 0;
   s_flock.l_len = 0; /* Until EOF.  */
   s_flock.l_pid = getpid();
+  s_flock.l_type = F_WRLCK;
 
-  s_flock.l_type = F_WRLCK;
+  while (fcntl(fd, F_SETLKW, &s_flock) == -1) {
+    if (errno != EINTR) {
+      if (errno == ENOLCK) {
+	return -1;
+      }
+      break;
+    }
+  }
+  return 0;
+#else
+  flock(fd, LOCK_EX);
+  return 0;
+#endif
+}
+
+COMPILER_RT_VISIBILITY int lprofUnlockFd(int fd) {
+#ifdef COMPILER_RT_HAS_FCNTL_LCK
+  struct flock s_flock;
+
+  s_flock.l_whence = SEEK_SET;
+  s_flock.l_start = 0;
+  s_flock.l_len = 0; /* Until EOF.  */
+  s_flock.l_pid = getpid();
+  s_flock.l_type = F_UNLCK;
+
+  while (fcntl(fd, F_SETLKW, &s_flock) == -1) {
+    if (errno != EINTR) {
+      if (errno == ENOLCK) {
+	return -1;
+      }
+      break;
+    }
+  }
+  return 0;
+#else
+  flock(fd, LOCK_UN);
+  return 0;
+#endif
+}
+
+COMPILER_RT_VISIBILITY FILE *lprofOpenFileEx(const char *ProfileName) {
+  FILE *f;
+  int fd;
+#ifdef COMPILER_RT_HAS_FCNTL_LCK
   fd = open(ProfileName, O_RDWR | O_CREAT, 0666);
   if (fd < 0)
     return NULL;
 
-  while (fcntl(fd, F_SETLKW, &s_flock) == -1) {
-    if (errno != EINTR) {
-      if (errno == ENOLCK) {
-        PROF_WARN("Data may be corrupted during profile merging : %s\n",
-                  "Fail to obtain file lock due to system limit.");
-      }
-      break;
-    }
-  }
+  if (lprofLockFd(fd) != 0)
+    PROF_WARN("Data may be corrupted during profile merging : %s\n",
+              "Fail to obtain file lock due to system limit.");
 
   f = fdopen(fd, "r+b");
 #elif defined(_WIN32)