ModuleMaker.cpp revision 31895e73591d3c9ceae731a1274c8f56194b9616
1//===- examples/ModuleMaker/ModuleMaker.cpp - Example project ---*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This programs is a simple example that creates an LLVM module "from scratch", 11// emitting it as a bitcode file to standard out. This is just to show how 12// LLVM projects work and to demonstrate some of the LLVM APIs. 13// 14//===----------------------------------------------------------------------===// 15 16#include "llvm/LLVMContext.h" 17#include "llvm/Module.h" 18#include "llvm/DerivedTypes.h" 19#include "llvm/Constants.h" 20#include "llvm/Instructions.h" 21#include "llvm/Bitcode/ReaderWriter.h" 22#include <iostream> 23using namespace llvm; 24 25int main() { 26 LLVMContext Context; 27 28 // Create the "module" or "program" or "translation unit" to hold the 29 // function 30 Module *M = new Module("test", Context); 31 32 // Create the main function: first create the type 'int ()' 33 FunctionType *FT = FunctionType::get(Type::Int32Ty, /*not vararg*/false); 34 35 // By passing a module as the last parameter to the Function constructor, 36 // it automatically gets appended to the Module. 37 Function *F = Function::Create(FT, Function::ExternalLinkage, "main", M); 38 39 // Add a basic block to the function... again, it automatically inserts 40 // because of the last argument. 41 BasicBlock *BB = BasicBlock::Create("EntryBlock", F); 42 43 // Get pointers to the constant integers... 44 Value *Two = ConstantInt::get(Type::Int32Ty, 2); 45 Value *Three = ConstantInt::get(Type::Int32Ty, 3); 46 47 // Create the add instruction... does not insert... 48 Instruction *Add = BinaryOperator::Create(Instruction::Add, Two, Three, 49 "addresult"); 50 51 // explicitly insert it into the basic block... 52 BB->getInstList().push_back(Add); 53 54 // Create the return instruction and add it to the basic block 55 BB->getInstList().push_back(ReturnInst::Create(Add)); 56 57 // Output the bitcode file to stdout 58 WriteBitcodeToFile(M, std::cout); 59 60 // Delete the module and all of its contents. 61 delete M; 62 return 0; 63} 64