LLVM编译C++测试

安装命令 

sudo apt install clang

sudo apt-get install llvm

源码 hello.cpp

#include <iostream>
using namespace std;
int main(){cout << "hello world" << endl;return 0;
}

编译 

clang++ -emit-llvm -S hello.cpp -o hello.ll

执行后，生成文件hello.ll

opt -O3 hello.ll -o optimized.ll 

lkmao@ubuntu:~/llvm$ ls
hello.cpp  hello.ll  optimized.ll
lkmao@ubuntu:~/llvm$ 

生成汇编代码 

lkmao@ubuntu:~/llvm$ llc optimized.ll -o output.s
lkmao@ubuntu:~/llvm$ ls
hello.cpp  hello.ll  optimized.ll  output.s
lkmao@ubuntu:~/llvm$ 
 

生成可执行文件 

clang++ output.s -o hello

lkmao@ubuntu:~/llvm$ clang++ output.s -o hello
lkmao@ubuntu:~/llvm$ ls
hello  hello.cpp  hello.ll  optimized.ll  output.s
lkmao@ubuntu:~/llvm$  

或者 

clang output.s -o hello_c -lstdc++

lkmao@ubuntu:~/llvm$ clang output.s -o hello_c -lstdc++
lkmao@ubuntu:~/llvm$ ls
hello  hello_c  hello.cpp  hello.ll  optimized.ll  output.s
lkmao@ubuntu:~/llvm$ 
 

测试结果

 lkmao@ubuntu:~/llvm$ ./hello
hello world
lkmao@ubuntu:~/llvm$ ./hello_c 
hello world
lkmao@ubuntu:~/llvm$ 

小结