1 //===- examples/ModuleMaker/ModuleMaker.cpp - Example project ---*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file was developed by the LLVM research group and is distributed under 6 // the University of Illinois Open Source 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 bytecode 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/Module.h" 17 #include "llvm/DerivedTypes.h" 18 #include "llvm/Constants.h" 19 #include "llvm/Instructions.h" 20 #include "llvm/Bytecode/Writer.h" 21 #include <iostream> 22 23 using namespace llvm; 24 25 int main() { 26 // Create the "module" or "program" or "translation unit" to hold the 27 // function 28 Module *M = new Module("test"); 29 30 // Create the main function: first create the type 'int ()' 31 FunctionType *FT = FunctionType::get(Type::IntTy, std::vector<const Type*>(), 32 /*not vararg*/false); 33 34 // By passing a module as the last parameter to the Function constructor, 35 // it automatically gets appended to the Module. 36 Function *F = new Function(FT, Function::ExternalLinkage, "main", M); 37 38 // Add a basic block to the function... again, it automatically inserts 39 // because of the last argument. 40 BasicBlock *BB = new BasicBlock("EntryBlock", F); 41 42 // Get pointers to the constant integers... 43 Value *Two = ConstantSInt::get(Type::IntTy, 2); 44 Value *Three = ConstantSInt::get(Type::IntTy, 3); 45 46 // Create the add instruction... does not insert... 47 Instruction *Add = BinaryOperator::create(Instruction::Add, Two, Three, 48 "addresult"); 49 50 // explicitly insert it into the basic block... 51 BB->getInstList().push_back(Add); 52 53 // Create the return instruction and add it to the basic block 54 BB->getInstList().push_back(new ReturnInst(Add)); 55 56 // Output the bytecode file to stdout 57 WriteBytecodeToFile(M, std::cout); 58 59 // Delete the module and all of its contents. 60 delete M; 61 return 0; 62 } 63