Add atomicops for AIX/POWER + IBM xlC compiler.
diff --git a/src/google/protobuf/stubs/atomicops.h b/src/google/protobuf/stubs/atomicops.h
index b1336e3..bbe2d84 100644
--- a/src/google/protobuf/stubs/atomicops.h
+++ b/src/google/protobuf/stubs/atomicops.h
@@ -62,6 +62,15 @@
 namespace protobuf {
 namespace internal {
 
+#if defined(GOOGLE_PROTOBUF_ARCH_POWER)
+#if defined(_LP64) || defined(__LP64__)
+typedef int32 Atomic32;
+typedef intptr_t Atomic64;
+#else
+typedef intptr_t Atomic32;
+typedef int64 Atomic64;
+#endif
+#else
 typedef int32 Atomic32;
 #ifdef GOOGLE_PROTOBUF_ARCH_64_BIT
 // We need to be able to go between Atomic64 and AtomicWord implicitly.  This
@@ -75,6 +84,7 @@
 typedef intptr_t Atomic64;
 #endif
 #endif
+#endif
 
 // Use AtomicWord for a machine-sized pointer.  It will use the Atomic32 or
 // Atomic64 routines below, depending on your architecture.
@@ -179,6 +189,10 @@
 #elif defined(GOOGLE_PROTOBUF_OS_SOLARIS)
 #include <google/protobuf/stubs/atomicops_internals_solaris.h>
 
+// AIX
+#elif defined(GOOGLE_PROTOBUF_OS_AIX)
+#include <google/protobuf/stubs/atomicops_internals_aix.h>
+
 // Apple.
 #elif defined(GOOGLE_PROTOBUF_OS_APPLE)
 #include <google/protobuf/stubs/atomicops_internals_macosx.h>
diff --git a/src/google/protobuf/stubs/atomicops_internals_aix.h b/src/google/protobuf/stubs/atomicops_internals_aix.h
new file mode 100644
index 0000000..b8a42f2
--- /dev/null
+++ b/src/google/protobuf/stubs/atomicops_internals_aix.h
@@ -0,0 +1,440 @@
+// Copyright 2014 Bloomberg Finance LP. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Bloomberg Finance LP. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// This file is an internal atomic implementation, use atomicops.h instead.
+
+#ifndef GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_AIX_H_
+#define GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_AIX_H_
+
+namespace google {
+namespace protobuf {
+namespace internal {
+
+inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
+                                         Atomic32 old_value,
+                                         Atomic32 new_value) {
+  Atomic32 result;
+
+  asm volatile (
+      "1:     lwarx %[res], %[zero], %[obj]   \n\t"  // load and reserve
+      "       cmpw %[cmp], %[res]             \n\t"  // compare values
+      "       bne- 2f                         \n\t"
+      "       stwcx. %[val], %[zero], %[obj]  \n\t"  // store new value
+      "       bne- 1b                         \n\t"
+      "2:                                     \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [cmp]  "b"   (old_value),
+                [val]  "b"   (new_value),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr,
+                                         Atomic32 new_value) {
+  Atomic32 result;
+
+  asm volatile (
+      "1:     lwarx %[res], %[zero], %[obj]       \n\t"
+      "       stwcx. %[val], %[zero], %[obj]      \n\t"
+      "       bne- 1b                             \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [val]  "b"   (new_value),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr,
+                                          Atomic32 increment) {
+  Atomic32 result;
+
+  asm volatile (
+      "1:     lwarx %[res], %[zero], %[obj]   \n\t"  // load and reserve
+      "       add %[res], %[val], %[res]      \n\t"  // add the operand
+      "       stwcx. %[res], %[zero], %[obj]  \n\t"  // store old value
+                                                     // if still reserved
+      "       bne- 1b                         \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [val]  "b"   (increment),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline void MemoryBarrier(void) {
+  asm volatile (
+      "       lwsync                          \n\t"
+      "       isync                           \n\t"
+              :
+              :
+              : "memory");
+}
+
+inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr,
+                                        Atomic32 increment) {
+  Atomic32 result;
+
+  asm volatile (
+      "       lwsync                          \n\t"
+
+      "1:     lwarx %[res], %[zero], %[obj]   \n\t"  // load and reserve
+      "       add %[res], %[val], %[res]      \n\t"  // add the operand
+      "       stwcx. %[res], %[zero], %[obj]  \n\t"  // store old value
+                                                     // if still reserved
+      "       bne- 1b                         \n\t"
+      "       isync                           \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [val]  "b"   (increment),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
+                                       Atomic32 old_value,
+                                       Atomic32 new_value) {
+  Atomic32 result;
+
+  asm volatile (
+      "1:     lwarx %[res], %[zero], %[obj]   \n\t"  // load and reserve
+      "       cmpw %[cmp], %[res]             \n\t"  // compare values
+      "       bne- 2f                         \n\t"
+      "       stwcx. %[val], %[zero], %[obj]  \n\t"  // store new value
+      "       bne- 1b                         \n\t"
+
+      "       isync                           \n\t"
+      "2:                                     \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [cmp]  "b"   (old_value),
+                [val]  "b"   (new_value),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
+                                       Atomic32 old_value,
+                                       Atomic32 new_value) {
+  Atomic32 result;
+
+  asm volatile (
+      "       lwsync                          \n\t"
+
+      "1:     lwarx %[res], %[zero], %[obj]   \n\t"  // load and reserve
+      "       cmpw %[cmp], %[res]             \n\t"  // compare values
+      "       bne- 2f                         \n\t"
+      "       stwcx. %[val], %[zero], %[obj]  \n\t"  // store new value
+      "       bne- 1b                         \n\t"
+
+      "2:                                     \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [cmp]  "b"   (old_value),
+                [val]  "b"   (new_value),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
+  *ptr = value;
+}
+
+inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) {
+  asm volatile (
+      "       stw %[val], %[obj]      \n\t"
+      "       isync                   \n\t"
+              : [obj] "=m" (*ptr)
+              : [val]  "b"  (value));
+}
+
+inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
+  asm volatile (
+      "       lwsync                  \n\t"
+      "       stw %[val], %[obj]      \n\t"
+              : [obj] "=m" (*ptr)
+              : [val]  "b"  (value));
+}
+
+inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
+  return *ptr;
+}
+
+inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) {
+  Atomic32 result;
+
+  asm volatile (
+      "1:     lwz %[res], %[obj]              \n\t"
+      "       cmpw %[res], %[res]             \n\t" // create data
+                                                    // dependency for
+                                                    // load/load ordering
+      "       bne- 1b                         \n\t" // never taken
+
+      "       isync                           \n\t"
+              : [res]  "=b" (result)
+              : [obj]  "m"  (*ptr),
+                [zero] "i"  (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline Atomic32 Release_Load(volatile const Atomic32* ptr) {
+  Atomic32 result;
+
+  asm volatile (
+      "       lwsync                          \n\t"
+
+      "1:     lwz %[res], %[obj]              \n\t"
+      "       cmpw %[res], %[res]             \n\t" // create data
+                                                    // dependency for
+                                                    // load/load ordering
+      "       bne- 1b                         \n\t" // never taken
+              : [res]  "=b" (result)
+              : [obj]  "m"  (*ptr),
+                [zero] "i"  (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+#ifdef GOOGLE_PROTOBUF_ARCH_64_BIT
+inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr,
+                                         Atomic64 old_value,
+                                         Atomic64 new_value) {
+  Atomic64 result;
+
+  asm volatile (
+      "1:     ldarx %[res], %[zero], %[obj]   \n\t"  // load and reserve
+      "       cmpd %[cmp], %[res]             \n\t"  // compare values
+      "       bne- 2f                         \n\t"
+
+      "       stdcx. %[val], %[zero], %[obj]  \n\t"  // store the new value
+      "       bne- 1b                         \n\t"
+      "2:                                     \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [cmp]  "b"   (old_value),
+                [val]  "b"   (new_value),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr,
+                                         Atomic64 new_value) {
+  Atomic64 result;
+
+  asm volatile (
+      "1:     ldarx %[res], %[zero], %[obj]       \n\t"
+      "       stdcx. %[val], %[zero], %[obj]      \n\t"
+      "       bne- 1b                             \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [val]  "b"   (new_value),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr,
+                                          Atomic64 increment) {
+  Atomic64 result;
+
+  asm volatile (
+      "1:     ldarx %[res], %[zero], %[obj]   \n\t" // load and reserve
+      "       add %[res], %[res], %[val]      \n\t" // add the operand
+      "       stdcx. %[res], %[zero], %[obj]  \n\t" // store old value if
+                                                    // still reserved
+
+      "       bne- 1b                         \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [val]  "b"   (increment),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr,
+                                        Atomic64 increment) {
+
+  Atomic64 result;
+
+  asm volatile (
+      "       lwsync                          \n\t"
+
+      "1:     ldarx %[res], %[zero], %[obj]   \n\t" // load and reserve
+      "       add %[res], %[res], %[val]      \n\t" // add the operand
+      "       stdcx. %[res], %[zero], %[obj]  \n\t" // store old value if
+                                                    // still reserved
+
+      "       bne- 1b                         \n\t"
+
+      "       isync                           \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [val]  "b"   (increment),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr,
+                                       Atomic64 old_value,
+                                       Atomic64 new_value) {
+  Atomic64 result;
+
+  asm volatile (
+      "1:     ldarx %[res], %[zero], %[obj]   \n\t"  // load and reserve
+      "       cmpd %[cmp], %[res]             \n\t"  // compare values
+      "       bne- 2f                         \n\t"
+
+      "       stdcx. %[val], %[zero], %[obj]  \n\t"  // store the new value
+      "       bne- 1b                         \n\t"
+      "       isync                           \n\t"
+      "2:                                     \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [cmp]  "b"   (old_value),
+                [val]  "b"   (new_value),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr,
+                                       Atomic64 old_value,
+                                       Atomic64 new_value) {
+  Atomic64 result;
+
+  asm volatile (
+      "       lwsync                          \n\t"
+
+      "1:     ldarx %[res], %[zero], %[obj]   \n\t"  // load and reserve
+      "       cmpd %[cmp], %[res]             \n\t"  // compare values
+      "       bne- 2f                         \n\t"
+
+      "       stdcx. %[val], %[zero], %[obj]  \n\t"  // store the new value
+      "       bne- 1b                         \n\t"
+      "2:                                     \n\t"
+              : [res]  "=&b" (result)
+              : [obj]  "b"   (ptr),
+                [cmp]  "b"   (old_value),
+                [val]  "b"   (new_value),
+                [zero] "i"   (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value) {
+  *ptr = value;
+}
+
+inline void Acquire_Store(volatile Atomic64* ptr, Atomic64 value) {
+  asm volatile (
+      "       std %[val], %[obj]          \n\t"
+      "       isync                       \n\t"
+              : [obj] "=m" (*ptr)
+              : [val] "b"  (value));
+}
+
+inline void Release_Store(volatile Atomic64* ptr, Atomic64 value) {
+  asm volatile (
+      "       lwsync                      \n\t"
+      "       std %[val], %[obj]          \n\t"
+              : [obj] "=m" (*ptr)
+              : [val] "b"  (value));
+}
+
+inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) {
+  return *ptr;
+}
+
+inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) {
+  Atomic64 result;
+
+  asm volatile (
+      "1:     ld %[res], %[obj]                   \n\t"
+      "       cmpd %[res], %[res]                 \n\t" // create data
+                                                        // dependency for
+                                                        // load/load ordering
+      "       bne- 1b                             \n\t" // never taken
+
+      "       isync                               \n\t"
+              : [res]  "=b" (result)
+              : [obj]  "m"  (*ptr),
+                [zero] "i"  (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+
+inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
+  Atomic64 result;
+
+  asm volatile (
+      "       lwsync                              \n\t"
+
+      "1:     ld %[res], %[obj]                   \n\t"
+      "       cmpd %[res], %[res]                 \n\t" // create data
+                                                        // dependency for
+                                                        // load/load ordering
+      "       bne- 1b                             \n\t" // never taken
+              : [res]  "=b" (result)
+              : [obj]  "m"  (*ptr),
+                [zero] "i"  (0)
+              : "cr0", "ctr");
+
+  return result;
+}
+#endif
+
+}  // namespace internal
+}  // namespace protobuf
+}  // namespace google
+
+#endif  // GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_SPARC_GCC_H_
diff --git a/src/google/protobuf/stubs/platform_macros.h b/src/google/protobuf/stubs/platform_macros.h
index 7956d07..1ff09b8 100644
--- a/src/google/protobuf/stubs/platform_macros.h
+++ b/src/google/protobuf/stubs/platform_macros.h
@@ -72,6 +72,9 @@
 #else
 #define GOOGLE_PROTOBUF_ARCH_32_BIT 1
 #endif
+#elif defined(_POWER)
+#define GOOGLE_PROTOBUF_ARCH_POWER 1
+#define GOOGLE_PROTOBUF_ARCH_64_BIT 1
 #elif defined(__GNUC__)
 # if (((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4))
 // We fallback to the generic Clang/GCC >= 4.7 implementation in atomicops.h
@@ -96,6 +99,8 @@
 #define GOOGLE_PROTOBUF_OS_NACL
 #elif defined(sun)
 #define GOOGLE_PROTOBUF_OS_SOLARIS
+#elif defined(_AIX)
+#define GOOGLE_PROTOBUF_OS_AIX
 #endif
 
 #undef GOOGLE_PROTOBUF_PLATFORM_ERROR