为了调试方便,有时我们需要在codegen代码中添加printf函数,打印调试信息
PrintTest.cpp
//clang++ PrintTest.cpp `llvm-config --cxxflags --ldflags --system-libs --libs core mcjit native` -o p
#include <iostream>
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/raw_os_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Scalar/GVN.h"
#include "KaleidoscopeJIT.h"
typedef void (*print_int32_ptr_t)(int32_t);
llvm::Function *get_printf(llvm::Module *mod)
{
const char *fun_name = "printf";
llvm::Function *func = mod->getFunction(fun_name);
if (func == nullptr)
{
llvm::FunctionType *func_type = llvm::FunctionType::get(
llvm::Type::getInt32Ty(mod->getContext()),
{llvm::Type::getInt8PtrTy(mod->getContext())},
true);
func = llvm::Function::Create(func_type, llvm::GlobalValue::ExternalLinkage, fun_name, mod);
}
return func;
}
int main()
{
llvm::LLVMContext context;
llvm::InitializeNativeTarget();
llvm::InitializeNativeTargetAsmPrinter();
llvm::InitializeNativeTargetAsmParser();
auto native_jit = llvm::make_unique<llvm::orc::KaleidoscopeJIT>();
auto module = llvm::make_unique<llvm::Module>("print_module", context);
module->setDataLayout(native_jit->getTargetMachine().createDataLayout());
const char *fun_name = "print_test";
llvm::FunctionType *func_type = llvm::FunctionType::get(
llvm::Type::getVoidTy(context),
{llvm::Type::getInt32Ty(context)},
false);
auto func_ptr = llvm::Function::Create(func_type, llvm::GlobalValue::ExternalLinkage, fun_name, module.get());
auto func_arg_iter = func_ptr->arg_begin();
func_arg_iter->setName("val_");
llvm::Value *arg_val = &(*func_arg_iter);
llvm::IRBuilder<> builder(context);
auto bb_entry = llvm::BasicBlock::Create(context, "entry", func_ptr);
builder.SetInsertPoint(bb_entry);
auto printf_ptr = get_printf(module.get());
builder.CreateCall(printf_ptr,
{builder.CreateGlobalStringPtr("in llvm fun, value = %d\n"), arg_val});
builder.CreateRetVoid();
llvm::raw_os_ostream os(std::cout);
module->print(os,nullptr);
auto jit_mod = native_jit->addModule(std::move(module));
auto print_sym = native_jit->findSymbol(fun_name);
if(!print_sym){
std::cout << "cant't find symbol : " << fun_name << std::endl;
return -1;
}
auto print_ptr = (print_int32_ptr_t)llvm::cantFail(print_sym.getAddress());
std::cout << "====================" << std::endl;
(*print_ptr)(12);
std::cout << "=====================" << std::endl;
native_jit->removeModule(jit_mod);
return 0;
}
KaleidoscopeJIT.h
//===- KaleidoscopeJIT.h - A simple JIT for Kaleidoscope --------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Contains a simple JIT definition for use in the kaleidoscope tutorials.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_EXECUTIONENGINE_ORC_KALEIDOSCOPEJIT_H
#define LLVM_EXECUTIONENGINE_ORC_KALEIDOSCOPEJIT_H
#include "llvm/ADT/iterator_range.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/ExecutionEngine/JITSymbol.h"
#include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
#include "llvm/ExecutionEngine/SectionMemoryManager.h"
#include "llvm/ExecutionEngine/Orc/CompileUtils.h"
#include "llvm/ExecutionEngine/Orc/IRCompileLayer.h"
#include "llvm/ExecutionEngine/Orc/LambdaResolver.h"
#include "llvm/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Mangler.h"
#include "llvm/Support/DynamicLibrary.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include <algorithm>
#include <memory>
#include <string>
#include <vector>
namespace llvm {
namespace orc {
class KaleidoscopeJIT {
public:
using ObjLayerT = RTDyldObjectLinkingLayer;
using CompileLayerT = IRCompileLayer<ObjLayerT, SimpleCompiler>;
using ModuleHandleT = CompileLayerT::ModuleHandleT;
KaleidoscopeJIT()
: TM(EngineBuilder().selectTarget()), DL(TM->createDataLayout()),
ObjectLayer([]() { return std::make_shared<SectionMemoryManager>(); }),
CompileLayer(ObjectLayer, SimpleCompiler(*TM)) {
llvm::sys::DynamicLibrary::LoadLibraryPermanently(nullptr);
}
TargetMachine &getTargetMachine() { return *TM; }
ModuleHandleT addModule(std::unique_ptr<Module> M) {
// We need a memory manager to allocate memory and resolve symbols for this
// new module. Create one that resolves symbols by looking back into the
// JIT.
auto Resolver = createLambdaResolver(
[&](const std::string &Name) {
if (auto Sym = findMangledSymbol(Name))
return Sym;
return JITSymbol(nullptr);
},
[](const std::string &S) { return nullptr; });
auto H = cantFail(CompileLayer.addModule(std::move(M),
std::move(Resolver)));
ModuleHandles.push_back(H);
return H;
}
void removeModule(ModuleHandleT H) {
ModuleHandles.erase(find(ModuleHandles, H));
cantFail(CompileLayer.removeModule(H));
}
JITSymbol findSymbol(const std::string Name) {
return findMangledSymbol(mangle(Name));
}
private:
std::string mangle(const std::string &Name) {
std::string MangledName;
{
raw_string_ostream MangledNameStream(MangledName);
Mangler::getNameWithPrefix(MangledNameStream, Name, DL);
}
return MangledName;
}
JITSymbol findMangledSymbol(const std::string &Name) {
#ifdef LLVM_ON_WIN32
// The symbol lookup of ObjectLinkingLayer uses the SymbolRef::SF_Exported
// flag to decide whether a symbol will be visible or not, when we call
// IRCompileLayer::findSymbolIn with ExportedSymbolsOnly set to true.
//
// But for Windows COFF objects, this flag is currently never set.
// For a potential solution see: https://reviews.llvm.org/rL258665
// For now, we allow non-exported symbols on Windows as a workaround.
const bool ExportedSymbolsOnly = false;
#else
const bool ExportedSymbolsOnly = true;
#endif
// Search modules in reverse order: from last added to first added.
// This is the opposite of the usual search order for dlsym, but makes more
// sense in a REPL where we want to bind to the newest available definition.
for (auto H : make_range(ModuleHandles.rbegin(), ModuleHandles.rend()))
if (auto Sym = CompileLayer.findSymbolIn(H, Name, ExportedSymbolsOnly))
return Sym;
// If we can't find the symbol in the JIT, try looking in the host process.
if (auto SymAddr = RTDyldMemoryManager::getSymbolAddressInProcess(Name))
return JITSymbol(SymAddr, JITSymbolFlags::Exported);
#ifdef LLVM_ON_WIN32
// For Windows retry without "_" at beginning, as RTDyldMemoryManager uses
// GetProcAddress and standard libraries like msvcrt.dll use names
// with and without "_" (for example "_itoa" but "sin").
if (Name.length() > 2 && Name[0] == '_')
if (auto SymAddr =
RTDyldMemoryManager::getSymbolAddressInProcess(Name.substr(1)))
return JITSymbol(SymAddr, JITSymbolFlags::Exported);
#endif
return nullptr;
}
std::unique_ptr<TargetMachine> TM;
const DataLayout DL;
ObjLayerT ObjectLayer;
CompileLayerT CompileLayer;
std::vector<ModuleHandleT> ModuleHandles;
};
} // end namespace orc
} // end namespace llvm
#endif // LLVM_EXECUTIONENGINE_ORC_KALEIDOSCOPEJIT_H
使用如下命令编译:
clang++ PrintTest.cpp `llvm-config --cxxflags --ldflags --system-libs --libs core mcjit native` -o p
输出结果:
; ModuleID = 'print_module'
source_filename = "print_module"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
@0 = private unnamed_addr constant [25 x i8] c"in llvm fun, value = %d\0A\00"
define void @print_test(i32 %val_) {
entry:
%0 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([25 x i8], [25 x i8]* @0, i32 0, i32 0), i32 %val_)
ret void
}
declare i32 @printf(i8*, ...)
====================
in llvm fun, value = 12
=====================