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//===- examples/ModuleMaker/ModuleMaker.cpp - Example project ---*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This programs is a simple example that creates an LLVM module "from scratch",
// emitting it as a bitcode file to standard out. This is just to show how
// LLVM projects work and to demonstrate some of the LLVM APIs.
#include "llvm/Bitcode/BitcodeWriter.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
int main() {
LLVMContext Context;
// Create the "module" or "program" or "translation unit" to hold the
// function
Module *M = new Module("test", Context);
// Create the main function: first create the type 'int ()'
FunctionType *FT =
FunctionType::get(Type::getInt32Ty(Context), /*not vararg*/false);
// By passing a module as the last parameter to the Function constructor,
// it automatically gets appended to the Module.
Function *F = Function::Create(FT, Function::ExternalLinkage, "main", M);
// Add a basic block to the function... again, it automatically inserts
// because of the last argument.
BasicBlock *BB = BasicBlock::Create(Context, "EntryBlock", F);
// Get pointers to the constant integers...
Value *Two = ConstantInt::get(Type::getInt32Ty(Context), 2);
Value *Three = ConstantInt::get(Type::getInt32Ty(Context), 3);
// Create the add instruction... does not insert...
Instruction *Add = BinaryOperator::Create(Instruction::Add, Two, Three,
// explicitly insert it into the basic block...
// Create the return instruction and add it to the basic block
BB->getInstList().push_back(ReturnInst::Create(Context, Add));
// Output the bitcode file to stdout
WriteBitcodeToFile(*M, outs());
// Delete the module and all of its contents.
delete M;
return 0;