blob: b1dfde49677e6ba0cd2abe1edafc2b2b15be2451 [file] [log] [blame]
From 810f9fae7e12142c3bd47ab7011ed071284760f8 Mon Sep 17 00:00:00 2001
From: Jun He <jun.he@arm.com>
Date: Fri, 5 Mar 2021 02:49:08 +0000
Subject: [PATCH] Backport atomic operations with support of arm64 and generic
Signed-off-by: Jun He <jun.he@arm.com>
---
src/Makefile.am | 2 +
src/google/protobuf/stubs/atomicops.h | 8 +-
.../stubs/atomicops_internals_arm64_gcc.h | 325 ++++++++++++++++++
.../stubs/atomicops_internals_generic_gcc.h | 137 ++++++++
src/google/protobuf/stubs/platform_macros.h | 16 +
5 files changed, 486 insertions(+), 2 deletions(-)
create mode 100644 src/google/protobuf/stubs/atomicops_internals_arm64_gcc.h
create mode 100644 src/google/protobuf/stubs/atomicops_internals_generic_gcc.h
diff --git a/src/Makefile.am b/src/Makefile.am
index df733d9b8..f9fa82ec0 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -40,6 +40,7 @@ MAINTAINERCLEANFILES = \
nobase_include_HEADERS = \
google/protobuf/stubs/atomicops.h \
google/protobuf/stubs/atomicops_internals_arm_gcc.h \
+ google/protobuf/stubs/atomicops_internals_arm64_gcc.h \
google/protobuf/stubs/atomicops_internals_arm_qnx.h \
google/protobuf/stubs/atomicops_internals_atomicword_compat.h \
google/protobuf/stubs/atomicops_internals_macosx.h \
@@ -47,6 +48,7 @@ nobase_include_HEADERS = \
google/protobuf/stubs/atomicops_internals_pnacl.h \
google/protobuf/stubs/atomicops_internals_x86_gcc.h \
google/protobuf/stubs/atomicops_internals_x86_msvc.h \
+ google/protobuf/stubs/atomicops_internals_generic_gcc.h \
google/protobuf/stubs/common.h \
google/protobuf/stubs/platform_macros.h \
google/protobuf/stubs/once.h \
diff --git a/src/google/protobuf/stubs/atomicops.h b/src/google/protobuf/stubs/atomicops.h
index b8581fa27..5b2e64cb5 100644
--- a/src/google/protobuf/stubs/atomicops.h
+++ b/src/google/protobuf/stubs/atomicops.h
@@ -176,14 +176,18 @@ GOOGLE_PROTOBUF_ATOMICOPS_ERROR
#elif defined(__GNUC__)
#if defined(GOOGLE_PROTOBUF_ARCH_IA32) || defined(GOOGLE_PROTOBUF_ARCH_X64)
#include <google/protobuf/stubs/atomicops_internals_x86_gcc.h>
-#elif defined(GOOGLE_PROTOBUF_ARCH_ARM)
+#elif defined(GOOGLE_PROTOBUF_ARCH_ARM) && defined(__linux__)
#include <google/protobuf/stubs/atomicops_internals_arm_gcc.h>
+#elif defined(GOOGLE_PROTOBUF_ARCH_AARCH64)
+#include <google/protobuf/stubs/atomicops_internals_arm64_gcc.h>
#elif defined(GOOGLE_PROTOBUF_ARCH_ARM_QNX)
#include <google/protobuf/stubs/atomicops_internals_arm_qnx.h>
-#elif defined(GOOGLE_PROTOBUF_ARCH_MIPS)
+#elif defined(GOOGLE_PROTOBUF_ARCH_MIPS) || defined(GOOGLE_PROTOBUF_ARCH_MIPS64)
#include <google/protobuf/stubs/atomicops_internals_mips_gcc.h>
#elif defined(__pnacl__)
#include <google/protobuf/stubs/atomicops_internals_pnacl.h>
+#elif (((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4))
+#include <google/protobuf/stubs/atomicops_internals_generic_gcc.h>
#else
GOOGLE_PROTOBUF_ATOMICOPS_ERROR
#endif
diff --git a/src/google/protobuf/stubs/atomicops_internals_arm64_gcc.h b/src/google/protobuf/stubs/atomicops_internals_arm64_gcc.h
new file mode 100644
index 000000000..fe9727ad0
--- /dev/null
+++ b/src/google/protobuf/stubs/atomicops_internals_arm64_gcc.h
@@ -0,0 +1,325 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2012 Google Inc. All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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 Google Inc. 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_ARM64_GCC_H_
+#define GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_ARM64_GCC_H_
+
+namespace google {
+namespace protobuf {
+namespace internal {
+
+inline void MemoryBarrier() {
+ __asm__ __volatile__ ("dmb ish" ::: "memory"); // NOLINT
+}
+
+// NoBarrier versions of the operation include "memory" in the clobber list.
+// This is not required for direct usage of the NoBarrier versions of the
+// operations. However this is required for correctness when they are used as
+// part of the Acquire or Release versions, to ensure that nothing from outside
+// the call is reordered between the operation and the memory barrier. This does
+// not change the code generated, so has no or minimal impact on the
+// NoBarrier operations.
+
+inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value) {
+ Atomic32 prev;
+ int32_t temp;
+
+ __asm__ __volatile__ ( // NOLINT
+ "0: \n\t"
+ "ldxr %w[prev], %[ptr] \n\t" // Load the previous value.
+ "cmp %w[prev], %w[old_value] \n\t"
+ "bne 1f \n\t"
+ "stxr %w[temp], %w[new_value], %[ptr] \n\t" // Try to store the new value.
+ "cbnz %w[temp], 0b \n\t" // Retry if it did not work.
+ "1: \n\t"
+ : [prev]"=&r" (prev),
+ [temp]"=&r" (temp),
+ [ptr]"+Q" (*ptr)
+ : [old_value]"IJr" (old_value),
+ [new_value]"r" (new_value)
+ : "cc", "memory"
+ ); // NOLINT
+
+ return prev;
+}
+
+inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr,
+ Atomic32 new_value) {
+ Atomic32 result;
+ int32_t temp;
+
+ __asm__ __volatile__ ( // NOLINT
+ "0: \n\t"
+ "ldxr %w[result], %[ptr] \n\t" // Load the previous value.
+ "stxr %w[temp], %w[new_value], %[ptr] \n\t" // Try to store the new value.
+ "cbnz %w[temp], 0b \n\t" // Retry if it did not work.
+ : [result]"=&r" (result),
+ [temp]"=&r" (temp),
+ [ptr]"+Q" (*ptr)
+ : [new_value]"r" (new_value)
+ : "memory"
+ ); // NOLINT
+
+ return result;
+}
+
+inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr,
+ Atomic32 increment) {
+ Atomic32 result;
+ int32_t temp;
+
+ __asm__ __volatile__ ( // NOLINT
+ "0: \n\t"
+ "ldxr %w[result], %[ptr] \n\t" // Load the previous value.
+ "add %w[result], %w[result], %w[increment]\n\t"
+ "stxr %w[temp], %w[result], %[ptr] \n\t" // Try to store the result.
+ "cbnz %w[temp], 0b \n\t" // Retry on failure.
+ : [result]"=&r" (result),
+ [temp]"=&r" (temp),
+ [ptr]"+Q" (*ptr)
+ : [increment]"IJr" (increment)
+ : "memory"
+ ); // NOLINT
+
+ return result;
+}
+
+inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr,
+ Atomic32 increment) {
+ MemoryBarrier();
+ Atomic32 result = NoBarrier_AtomicIncrement(ptr, increment);
+ MemoryBarrier();
+
+ return result;
+}
+
+inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value) {
+ Atomic32 prev = NoBarrier_CompareAndSwap(ptr, old_value, new_value);
+ MemoryBarrier();
+
+ return prev;
+}
+
+inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value) {
+ MemoryBarrier();
+ Atomic32 prev = NoBarrier_CompareAndSwap(ptr, old_value, new_value);
+
+ return prev;
+}
+
+inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
+ *ptr = value;
+}
+
+inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) {
+ *ptr = value;
+ MemoryBarrier();
+}
+
+inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
+ __asm__ __volatile__ ( // NOLINT
+ "stlr %w[value], %[ptr] \n\t"
+ : [ptr]"=Q" (*ptr)
+ : [value]"r" (value)
+ : "memory"
+ ); // NOLINT
+}
+
+inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
+ return *ptr;
+}
+
+inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) {
+ Atomic32 value;
+
+ __asm__ __volatile__ ( // NOLINT
+ "ldar %w[value], %[ptr] \n\t"
+ : [value]"=r" (value)
+ : [ptr]"Q" (*ptr)
+ : "memory"
+ ); // NOLINT
+
+ return value;
+}
+
+inline Atomic32 Release_Load(volatile const Atomic32* ptr) {
+ MemoryBarrier();
+ return *ptr;
+}
+
+// 64-bit versions of the operations.
+// See the 32-bit versions for comments.
+
+inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr,
+ Atomic64 old_value,
+ Atomic64 new_value) {
+ Atomic64 prev;
+ int32_t temp;
+
+ __asm__ __volatile__ ( // NOLINT
+ "0: \n\t"
+ "ldxr %[prev], %[ptr] \n\t"
+ "cmp %[prev], %[old_value] \n\t"
+ "bne 1f \n\t"
+ "stxr %w[temp], %[new_value], %[ptr] \n\t"
+ "cbnz %w[temp], 0b \n\t"
+ "1: \n\t"
+ : [prev]"=&r" (prev),
+ [temp]"=&r" (temp),
+ [ptr]"+Q" (*ptr)
+ : [old_value]"IJr" (old_value),
+ [new_value]"r" (new_value)
+ : "cc", "memory"
+ ); // NOLINT
+
+ return prev;
+}
+
+inline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr,
+ Atomic64 new_value) {
+ Atomic64 result;
+ int32_t temp;
+
+ __asm__ __volatile__ ( // NOLINT
+ "0: \n\t"
+ "ldxr %[result], %[ptr] \n\t"
+ "stxr %w[temp], %[new_value], %[ptr] \n\t"
+ "cbnz %w[temp], 0b \n\t"
+ : [result]"=&r" (result),
+ [temp]"=&r" (temp),
+ [ptr]"+Q" (*ptr)
+ : [new_value]"r" (new_value)
+ : "memory"
+ ); // NOLINT
+
+ return result;
+}
+
+inline Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr,
+ Atomic64 increment) {
+ Atomic64 result;
+ int32_t temp;
+
+ __asm__ __volatile__ ( // NOLINT
+ "0: \n\t"
+ "ldxr %[result], %[ptr] \n\t"
+ "add %[result], %[result], %[increment] \n\t"
+ "stxr %w[temp], %[result], %[ptr] \n\t"
+ "cbnz %w[temp], 0b \n\t"
+ : [result]"=&r" (result),
+ [temp]"=&r" (temp),
+ [ptr]"+Q" (*ptr)
+ : [increment]"IJr" (increment)
+ : "memory"
+ ); // NOLINT
+
+ return result;
+}
+
+inline Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr,
+ Atomic64 increment) {
+ MemoryBarrier();
+ Atomic64 result = NoBarrier_AtomicIncrement(ptr, increment);
+ MemoryBarrier();
+
+ return result;
+}
+
+inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr,
+ Atomic64 old_value,
+ Atomic64 new_value) {
+ Atomic64 prev = NoBarrier_CompareAndSwap(ptr, old_value, new_value);
+ MemoryBarrier();
+
+ return prev;
+}
+
+inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr,
+ Atomic64 old_value,
+ Atomic64 new_value) {
+ MemoryBarrier();
+ Atomic64 prev = NoBarrier_CompareAndSwap(ptr, old_value, new_value);
+
+ return prev;
+}
+
+inline void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value) {
+ *ptr = value;
+}
+
+inline void Acquire_Store(volatile Atomic64* ptr, Atomic64 value) {
+ *ptr = value;
+ MemoryBarrier();
+}
+
+inline void Release_Store(volatile Atomic64* ptr, Atomic64 value) {
+ __asm__ __volatile__ ( // NOLINT
+ "stlr %x[value], %[ptr] \n\t"
+ : [ptr]"=Q" (*ptr)
+ : [value]"r" (value)
+ : "memory"
+ ); // NOLINT
+}
+
+inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) {
+ return *ptr;
+}
+
+inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) {
+ Atomic64 value;
+
+ __asm__ __volatile__ ( // NOLINT
+ "ldar %x[value], %[ptr] \n\t"
+ : [value]"=r" (value)
+ : [ptr]"Q" (*ptr)
+ : "memory"
+ ); // NOLINT
+
+ return value;
+}
+
+inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
+ MemoryBarrier();
+ return *ptr;
+}
+
+} // namespace internal
+} // namespace protobuf
+} // namespace google
+
+#endif // GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_ARM64_GCC_H_
diff --git a/src/google/protobuf/stubs/atomicops_internals_generic_gcc.h b/src/google/protobuf/stubs/atomicops_internals_generic_gcc.h
new file mode 100644
index 000000000..e30bb4449
--- /dev/null
+++ b/src/google/protobuf/stubs/atomicops_internals_generic_gcc.h
@@ -0,0 +1,137 @@
+// Copyright 2013 Red Hat Inc. 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 Red Hat Inc. 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_GENERIC_GCC_H_
+#define GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_GENERIC_GCC_H_
+
+namespace google {
+namespace protobuf {
+namespace internal {
+
+inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value) {
+ __atomic_compare_exchange_n(ptr, &old_value, new_value, true,
+ __ATOMIC_RELAXED, __ATOMIC_RELAXED);
+ return old_value;
+}
+
+inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr,
+ Atomic32 new_value) {
+ return __atomic_exchange_n(ptr, new_value, __ATOMIC_RELAXED);
+}
+
+inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr,
+ Atomic32 increment) {
+ return __atomic_add_fetch(ptr, increment, __ATOMIC_RELAXED);
+}
+
+inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr,
+ Atomic32 increment) {
+ return __atomic_add_fetch(ptr, increment, __ATOMIC_SEQ_CST);
+}
+
+inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value) {
+ __atomic_compare_exchange(ptr, &old_value, &new_value, true,
+ __ATOMIC_ACQUIRE, __ATOMIC_ACQUIRE);
+ return old_value;
+}
+
+inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value) {
+ __atomic_compare_exchange_n(ptr, &old_value, new_value, true,
+ __ATOMIC_RELEASE, __ATOMIC_ACQUIRE);
+ return old_value;
+}
+
+inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
+ __atomic_store_n(ptr, value, __ATOMIC_RELAXED);
+}
+
+inline void MemoryBarrier() {
+ __sync_synchronize();
+}
+
+inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) {
+ __atomic_store_n(ptr, value, __ATOMIC_ACQUIRE);
+}
+
+inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
+ __atomic_store_n(ptr, value, __ATOMIC_RELEASE);
+}
+
+inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
+ return __atomic_load_n(ptr, __ATOMIC_RELAXED);
+}
+
+inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) {
+ return __atomic_load_n(ptr, __ATOMIC_ACQUIRE);
+}
+
+inline Atomic32 Release_Load(volatile const Atomic32* ptr) {
+ return __atomic_load_n(ptr, __ATOMIC_RELEASE);
+}
+
+#ifdef __LP64__
+
+inline void Release_Store(volatile Atomic64* ptr, Atomic64 value) {
+ __atomic_store_n(ptr, value, __ATOMIC_RELEASE);
+}
+
+inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) {
+ return __atomic_load_n(ptr, __ATOMIC_ACQUIRE);
+}
+
+inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr,
+ Atomic64 old_value,
+ Atomic64 new_value) {
+ __atomic_compare_exchange_n(ptr, &old_value, new_value, true,
+ __ATOMIC_ACQUIRE, __ATOMIC_ACQUIRE);
+ return old_value;
+}
+
+inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr,
+ Atomic64 old_value,
+ Atomic64 new_value) {
+ __atomic_compare_exchange_n(ptr, &old_value, new_value, true,
+ __ATOMIC_RELAXED, __ATOMIC_RELAXED);
+ return old_value;
+}
+
+#endif // defined(__LP64__)
+
+} // namespace internal
+} // namespace protobuf
+} // namespace google
+
+#endif // GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_GENERIC_GCC_H_
diff --git a/src/google/protobuf/stubs/platform_macros.h b/src/google/protobuf/stubs/platform_macros.h
index b1df60e46..1705b4162 100644
--- a/src/google/protobuf/stubs/platform_macros.h
+++ b/src/google/protobuf/stubs/platform_macros.h
@@ -49,14 +49,30 @@
#elif defined(__ARMEL__)
#define GOOGLE_PROTOBUF_ARCH_ARM 1
#define GOOGLE_PROTOBUF_ARCH_32_BIT 1
+#elif defined(__aarch64__)
+#define GOOGLE_PROTOBUF_ARCH_AARCH64 1
+#define GOOGLE_PROTOBUF_ARCH_64_BIT 1
#elif defined(__MIPSEL__)
+#if defined(__LP64__)
+#define GOOGLE_PROTOBUF_ARCH_MIPS64 1
+#define GOOGLE_PROTOBUF_ARCH_64_BIT 1
+#else
#define GOOGLE_PROTOBUF_ARCH_MIPS 1
#define GOOGLE_PROTOBUF_ARCH_32_BIT 1
+#endif
#elif defined(__pnacl__)
#define GOOGLE_PROTOBUF_ARCH_32_BIT 1
#elif defined(__ppc__)
#define GOOGLE_PROTOBUF_ARCH_PPC 1
#define GOOGLE_PROTOBUF_ARCH_32_BIT 1
+#elif defined(__GNUC__) && \
+ (((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4))
+// We fallback to the generic GCC >= 4.7 implementation in atomicops.h
+# if __LP64__
+# define GOOGLE_PROTOBUF_ARCH_64_BIT 1
+# else
+# define GOOGLE_PROTOBUF_ARCH_32_BIT 1
+# endif
#else
#error Host architecture was not detected as supported by protobuf
#endif
--
2.17.1