LLVM Pass

This project is mainly used to save some practices of writing llvm pass, which is helpful for people who are unfamiliar with LLVM.

Directory Info

Introduce some information about several directories.

pass_example: there are some llvm pass example, like iterate BasicBlocks
	./info.txt: 对pass的功能进行说明
	
test_program: there are some C program, which is used to

write_ir: 用llvm架构，直接编写IR
	notice: 这些文件要放到 example 目录下

Notice: More information you can see in dir's doc file

How to Use These LLVM Pass

1. You should compile the LLVM for your platform

2. Select a LLVM Pass example, and copy it in LLVM

   cp -R pass_example/${LLVM_PASS} ${LLVM_HOME}/lib/Transforms

   add the pass_dir's description into CMakeLists.txt, just like "add_subdirectory(MyHello)"

   cd ${LLVM_BUILD}

   make

3. Test the LLVM Pass

   clang -emit-llvm -S -o ${TEST_FILE}.ll test_program/${TEST_FILE}.c

   opt -load ${LLVM_BUILD}/lib/LLVM${LLVM_PASS}.so -${LLVM_PASS_RegisterName} ${TEST_FILE}.ll

   例子：

   clang -emit-llvm -o main.ll -S main.c

   opt -load ~/develop/llvm_risc_ise/llvm_4_build/lib/LLVMcountOpcode.so -opcodeCounter main_itrBB.ll

Notice:
LLVM_HOME: llvm's home dir
LLVM_BUILD: the dir which is uesd to build llvm
LLVM_PASS: the llvm pass which you want to test
LLVM_PASS_RegisterName: the name used to register pass
TEST_FILE: test C file