computer_knowledge_notes/Languages/JavaScript/install-emcc.md

1. sudo apt update //更新软件包到最新状态

2. sudo apt install python2.7 //安装python2.7

3. sudo apt install nodejs //安装nodejs

4. sudo apt install build-essential 安装gcc sudo apt install cmake //安装cmake

5. sudo apt install git-core //安装git-core

6. sudo apt install default-jre //安装JavaScript

7. 编译安装Fastcomp(LLVM + Clang)

mkdir myfastcomp
cd myfastcomp
git clone https://github.com/kripken/emscripten-fastcomp
cd emscripten-fastcomp
git clone https://github.com/kripken/emscripten-fastcomp-clang tools/clang
mkdir duild
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD="X86;JSBackend" -DLLVM_INCLUDE_EXAMPLES=OFF -DLLVM_INCLUDE_TESTS=OFF -DCLANG_INCLUDE_EXAMPLES=OFF -DCLANG_INCLUDE_TESTS=OFF   // 使用cmake配置（cmake或configure二选一）
../configure --enable-optimized --disable-assertions --enable-targets=host,js   // 使用configure配置（cmake或configure二选一）
cat /proc/cpuinfo | grep "^cpu cores" | uniq    // 查询CPU核心数量，充分利用多核可以加快编译速度
make -j2    // 上步查到是2核，所以我用-j2参数，慢慢等待吧。。。

8. git clone https://github.com/kripken/emscripten.git //复制Emscripten

9. 修改配置文件~/.emscripten，将LLVM_ROOT设置为第7步的目录.../myfastcomp/emscripten-fastcomp/build/bin

10. ./emcc -v //在emscripten目录运行此命令，如果没报错即为安装正确

11. ./emcc tests/hello_world.c //如果没报错即为运行正确