Google Tensorflow 源码编译（一）：Protobuf<v3.0.0-alpha-3>

这几天终于把tensorflow安装上了，中间遇到过不少的问题，这里记录下来。供大家想源码安装的参考。

安装环境：POWER8处理器，Docker容器Ubuntu14.04镜像。

Build Protobuf<v3.0.0-alpha-3> for IBM POWER8 CPU from Source Code

My computer's os is ubuntu 14.04 , and I want to install protobuf v3.0.0-alpha-3, but there is no deb package in the repository, so I need to build from source code.
Here are the steps that I succeed to install protobuf<v3.0.0-alpha-3> on my computer:

1. Get source code
1.1 Get protobuf code
　　git clone https://github.com/google/protobuf
　　git checkout v3.0.0-alpha-3
1.2 Get gtest code
　　The latest protobuf version uses gmock, but v3.0.0-alpha-3 uses gtest. Anyway ,the following code always works!
　　git clone https://github.com/franramirez688/gmock(../ is the root path of protobuf)
　　cp ./gmock/gtest ../

2. Modify the code to support POWER cpu
2.1 Add g++ MACRO
　　in protobuf/src/google/protobuf/stubs/platform_macros.h:
　　change #elif defined(_POWER) to #elif defined(_POWER) || defined(__powerpc64__) || defined(__PPC64__).

2.2 Include power cpu header file
　　in protobuf/src/google/protobuf/stubs/atomicops.h, add:
　　if defined(GOOGLE_PROTOBUF_ARCH_POWER)
　　#include <google/protobuf/stubs/atomicops_internals_power.h>
　　endif
2.3 Add power cpu header file
　　add atomicops_internals_power.h to google/protobuf/stubs folder:
　　you can copy it from the latest version < v3.0.0-beta-1>

3. Compile source code
　　$ ./autogen.sh
　　$ ./configure
　　$ make
　　$ make install

4. the binary file <protoc> is saved at protobuf/src/protoc.