Llvm 13.1 new pass plug-in form [for win]

LLVM 13.1 new Pass Plug in form [for win]

4 Key points ：

1. LLVM 13.1 edition ( The latest edition )
2. windows On the platform pass demo
3. new pass form ( Not legacy)
4. clang Dynamic plug-in form (pass Plug in and llvm Ontology compilation separation )

background ：
The current external data are all old versions LLVM + legacy Mode pass, And the current llvm Version disjointed , In the new mode, I did my own research without finding any data , New and old LLVM Version pair pass What is the impact of writing , What is the specific reason , How to make it compatible with the old version? See my Last article ( The principle and thought of analyzing the similarities and differences between the old and the new design )

Operation steps
( In all subsequent steps, if the directory is inconsistent, you need to change the directory structure by yourself , Don't go into )

1. establish ：D:\Code\llvm-project Folder , Put in a file named clang Source folder for , And called llvm Source folder for , Create a new one in this directory MyCustom The folder is used to store our dynamic plug-in project （ edition LLVM 13.1）
2. According to my Last article Steps introduced 1~3 Build up x64release Version of clang&llvm( Old and new pass Yes llvm and clang There is no difference in the construction of ), Compilation is slow and CPU High occupancy, please find free time to complete
3. Switch to D:\Code\llvm-project\llvm\build\Release\bin Directory type .\clang.exe --version The command ensures that the output is in the following form

clang version 13.0.1
Target: x86_64-pc-windows-msvc
...

4. newly build D:\Code\llvm-project\MyCustom\src Folder , Create a new file MyPass.cpp And write

#include <llvm/IR/PassManager.h>
#include <llvm/IR/Module.h>
#include <llvm/Pass.h>
#include <llvm/Passes/PassBuilder.h>
#include <llvm/Passes/PassPlugin.h>


using namespace llvm;

// test for my custom pass
class MyCustomPass : public PassInfoMixin<MyCustomPass> {
    
public:
    PreservedAnalyses run(Module& M, ModuleAnalysisManager& AM)
    {
    
        for (auto& f : M) {
    
            errs() << "MyCustomPass: " << f.getName() << "\n";
        }
        return PreservedAnalyses::all();
    }
};

//  stay clang Create a custom according to the configuration pass,called by PassManagerBuilder::populateModulePassManager
extern "C"  __declspec(dllexport) void __stdcall clangAddCustomPass(ModulePassManager & MPM)
{
    
    MPM.addPass(MyCustomPass());
}

5. stay D:\Code\llvm-project\MyCustom New file in directory CMakeLists.txt, And write

cmake_minimum_required(VERSION 3.4)

project(custompass)

#  Set compilation mode 
set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /MD")        #/MT
set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /MDd")                #/MTd

#  Add source directory 
aux_source_directory(./src  src_1)
set(srcs ${src_1})

#  Generate DLL , So in Windows Next is dll, Will eventually generate custompass.dll
add_library(custompass SHARED ${srcs})

set(LLVM_PROJECT_DIR "" CACHE STRING
	"You must input the correct llvm-project dir")
if( LLVM_PROJECT_DIR STREQUAL "" )
	MESSAGE(FATAL_ERROR "LLVM_PROJECT_DIR is empty")
else()
	MESSAGE("LLVM_PROJECT_DIR=${LLVM_PROJECT_DIR}")
endif()

#  Add header file , You need compiled and source header files 
include_directories("${LLVM_PROJECT_DIR}/llvm/build/include")
include_directories("${LLVM_PROJECT_DIR}/llvm/include")

#  Add compiled lib
set(mylibdir "${LLVM_PROJECT_DIR}/llvm/build/Release/lib")
set(VTKLIBS LLVMCore LLVMSupport LLVMBinaryFormat LLVMRemarks LLVMBitstreamReader)
foreach(libname ${VTKLIBS})
        SET(FOUND_LIB "FOUND_LIB-NOTFOUND")
        find_library(FOUND_LIB NAMES ${libname} HINTS ${mylibdir} NO_DEFAULT_PATH)
                IF (FOUND_LIB)
                        message("found lib: ${FOUND_LIB}")
                        LIST(APPEND mylibs ${FOUND_LIB})
                ELSE()
                        MESSAGE("not lib found: ${libname}")
                ENDIF ()
endforeach(libname)
#message(${mylibs})

#message(${CPPUNIT_LIBRARY})
target_link_libraries(custompass PUBLIC ${mylibs})

6. cmake Choose D:\Code\llvm-project\MyCustom engineering , To configure LLVM_PROJECT_DIR Field is D:\Code\llvm-project, And ensure successful generation sln Engineering documents
7. Compile the project file to get custompass.dll The output file , Copy it to D:\Code\llvm-project\llvm\build\Release\bin Under the table of contents
8. open llvm engineering , In turn, open Object Libraries\obj.clangCodeGen\Source Files\BackendUtil.cpp file
9. stay EmitAssemblyHelper::EmitAssemblyWithNewPassManager In function if (!CodeGenOpts.DisableLLVMPasses) Add the following code to the end of the judgment body to make it load fixedly custompass.dll Of clangAddCustomPass The export function ( Remember to introduce #include "windows.h")

#if _WINDOWS
    using myPassType = void(__stdcall *)(ModulePassManager & MPM);
    auto customHandle = ::LoadLibraryA("custompass.dll");
    if (!customHandle) {
    
      errs() << "custompass.dll not found\n";
    } else {
    
      auto pfn =
          (myPassType)::GetProcAddress(customHandle, "clangAddCustomPass");
      if (pfn != NULL) {
    
        pfn(MPM);
      } else {
    
        errs() << "clangAddCustomPass not found\n";
      }
    }
#endif // _WINDOWS

10. Incremental compilation LLVM engineering ( Little modification and faster compilation )

test
12. D:\Code\llvm-project\llvm\build\Release\bin Next new file test.cpp, And write

#include <stdio.h>

int add(int a,int b)
{
    
	return a+b;
}

int min(int a,int b)
{
    
	return a-b;
}

void show()
{
    
	printf("show\n");
}

int main(int argc, char* argv[]){
    
	add(1,2);
	min(5,3);
	show();
	return 0;	
}

2. Enter the command .\clang.exe test.cpp -o test.exe Successful output , It only needs to be modified later MyCustom Project and put the compiled plug-in into clang directory , At the same time, the project supports the addition of multiple PASS, First the pass Understand the process PASS Process logic &llvm Syntax component of … Some code is confusing , Data encryption and other functions will be issued later

MyCustomPass: [email protected]@[email protected]
MyCustomPass: [email protected]@[email protected]
MyCustomPass: [email protected]@YAXXZ
MyCustomPass: printf
MyCustomPass: main
MyCustomPass: llvm.va_start
MyCustomPass: _vfprintf_l
MyCustomPass: __acrt_iob_func
MyCustomPass: llvm.va_end
MyCustomPass: __stdio_common_vfprintf
MyCustomPass: __local_stdio_printf_options