安装clang和cmake
sudo apt-get install clang cmake
安装llvm
sudo apt-get install llvm
使用这种方法我默认安装上的llvm版本为3.8.0，安装后的文件目录为/usr/share/llvm-3.8
修改LLVMConfig.cmake文件
set(LLVM_CMAKE_DIR "${LLVM_INSTALL_PREFIX}/share/llvm/cmake")
改为
set(LLVM_CMAKE_DIR "${LLVM_INSTALL_PREFIX}/share/llvm-3.8/cmake")
修改LLVMExports-relwithdebinfo.cmake文件
由于权限问题不能直接打开修改，在命令行中写入:
sudo gedit LLVMExports-relwithdebinfo.cmake
对文件进行如下修改:
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| #Commands may need to know the format version.
set(CMAKE_IMPORT_FILE_VERSION 1)
set(_IMPORT_PREFIX "/usr/lib/llvm-3.8")
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注释与Polly相关的库引用
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| # Import target "PollyISL" for configuration "RelWithDebInfo"
# set_property(TARGET PollyISL APPEND PROPERTY IMPORTED_CONFIGURATIONS RELWITHDEBINFO)
# set_target_properties(PollyISL PROPERTIES
# IMPORTED_LINK_INTERFACE_LANGUAGES_RELWITHDEBINFO "C"
# IMPORTED_LOCATION_RELWITHDEBINFO "${_IMPORT_PREFIX}/lib/libPollyISL.a"
# )
#
# list(APPEND _IMPORT_CHECK_TARGETS PollyISL )
# list(APPEND _IMPORT_CHECK_FILES_FOR_PollyISL "${_IMPORT_PREFIX}/lib/libPollyISL.a" )
#
# # Import target "Polly" for configuration "RelWithDebInfo"
# set_property(TARGET Polly APPEND PROPERTY IMPORTED_CONFIGURATIONS RELWITHDEBINFO)
# set_target_properties(Polly PROPERTIES
# IMPORTED_LINK_INTERFACE_LANGUAGES_RELWITHDEBINFO "CXX"
# IMPORTED_LOCATION_RELWITHDEBINFO "${_IMPORT_PREFIX}/lib/libPolly.a"
# )
#
# list(APPEND _IMPORT_CHECK_TARGETS Polly )
# list(APPEND _IMPORT_CHECK_FILES_FOR_Polly "${_IMPORT_PREFIX}/lib/libPolly.a" )
#
# # Import target "LLVMPolly" for configuration "RelWithDebInfo"
# set_property(TARGET LLVMPolly APPEND PROPERTY IMPORTED_CONFIGURATIONS RELWITHDEBINFO)
# set_target_properties(LLVMPolly PROPERTIES
# IMPORTED_LOCATION_RELWITHDEBINFO "${_IMPORT_PREFIX}/lib/LLVMPolly.so"
# IMPORTED_NO_SONAME_RELWITHDEBINFO "TRUE"
# )
#
# list(APPEND _IMPORT_CHECK_TARGETS LLVMPolly )
# list(APPEND _IMPORT_CHECK_FILES_FOR_LLVMPolly "${_IMPORT_PREFIX}/lib/LLVMPolly.so" )
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使用LLVM进行开发
新建文件夹: HowToUseJIT
目录结构如下:
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| HowToUseJIT
-- src
+ -- HowToUseJIT.cpp
-- CMakeLists.txt
-- build
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在HowToUseJIT文件夹下进行如下操作:
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| cd build
cmake ..
make
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HowToUseJIT.cpp和CMakeLists.txt文件可以自己根据LLVM提供的API自行开发，也可以使用下面所给的例子：
HowToUseJIT.cpp
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| #include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/IRBuilder.h"
#include <vector>
#include <string>
int main()
{
llvm::LLVMContext & context = llvm::getGlobalContext();
llvm::Module *module = new llvm::Module("asdf", context);
llvm::IRBuilder<> builder(context);
llvm::FunctionType *funcType = llvm::FunctionType::get(builder.getVoidTy(), false);
llvm::Function *mainFunc =
llvm::Function::Create(funcType, llvm::Function::ExternalLinkage, "main", module);
llvm::BasicBlock *entry = llvm::BasicBlock::Create(context, "entrypoint", mainFunc);
builder.SetInsertPoint(entry);
llvm::Value *helloWorld = builder.CreateGlobalStringPtr("hello world!\n");
std::vector<llvm::Type *> putsArgs;
putsArgs.push_back(builder.getInt8Ty()->getPointerTo());
llvm::ArrayRef<llvm::Type*> argsRef(putsArgs);
llvm::FunctionType *putsType =
llvm::FunctionType::get(builder.getInt32Ty(), argsRef, false);
//llvm::Constant *putsFunc = module->getOrInsertFunction("puts", putsType);
llvm::Function *putsFunc =
llvm::Function::Create(putsType, llvm::Function::ExternalLinkage, "puts", module);
llvm::BasicBlock *putsentry = llvm::BasicBlock::Create(context, "entrypoint", putsFunc);
builder.SetInsertPoint(putsentry);
builder.CreateCall(putsFunc, helloWorld);
builder.CreateRetVoid();
module->dump();
}
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CMakeLists.txt
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| cmake_minimum_required(VERSION 2.8)
project(llvm_test)
set(LLVM_TARGETS_TO_BUILD X86)
set(LLVM_BUILD_RUNTIME OFF)
set(LLVM_BUILD_TOOLS OFF)
find_package(LLVM REQUIRED CONFIG)
message(STATUS "Found LLVM ${LLVM_INCLUDE_DIRS}")
message(STATUS "Using LLVMConfig.cmake in: ${LLVM_DIR}")
SET (CMAKE_CXX_COMPILER_ENV_VAR "clang++")
SET (CMAKE_CXX_FLAGS "-std=c++11")
SET (CMAKE_CXX_FLAGS_DEBUG "-g")
SET (CMAKE_CXX_FLAGS_MINSIZEREL "-Os -DNDEBUG")
SET (CMAKE_CXX_FLAGS_RELEASE "-O4 -DNDEBUG")
SET (CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O2 -g")
SET(EXECUTABLE_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/bin)
include_directories(${LLVM_INCLUDE_DIRS})
add_definitions(${LLVM_DEFINITIONS})
file(GLOB_RECURSE source_files "${CMAKE_CURRENT_SOURCE_DIR}/src/*.cpp")
add_executable(llvm_test ${source_files})
install(TARGETS llvm_test RUNTIME DESTINATION bin)
# Find the libraries that correspond to the LLVM components
# that we wish to use
llvm_map_components_to_libnames(llvm_libs
Core
ExecutionEngine
Interpreter
MC
Support
nativecodegen)
# Link against LLVM libraries
target_link_libraries(llvm_test ${llvm_libs})
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如果编译通过说明LLVM开发环境搭建成功，如果报一些库文件缺失的错误有可能是因为默认LLVM文件夹的文件名为llvm而安装LLVM后自带的文件名为llvm-3.8可以根据报错内容对/usr/share/llvm-3.8或usr/lib/llvm-3.8的文件名进行修改
