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/Bitcode/ReaderWriter.h" 17 #include "llvm/IR/BasicBlock.h" 18 #include "llvm/IR/Constants.h" 19 #include "llvm/IR/DerivedTypes.h" 20 #include "llvm/IR/Function.h" 21 #include "llvm/IR/InstrTypes.h" 22 #include "llvm/IR/Instruction.h" 23 #include "llvm/IR/Instructions.h" 24 #include "llvm/IR/LLVMContext.h" 25 #include "llvm/IR/Module.h" 26 #include "llvm/IR/Type.h" 27 #include "llvm/Support/raw_ostream.h" 28 29 using namespace llvm; 30 31 int main() { 32 LLVMContext Context; 33 34 // Create the "module" or "program" or "translation unit" to hold the 35 // function 36 Module *M = new Module("test", Context); 37 38 // Create the main function: first create the type 'int ()' 39 FunctionType *FT = 40 FunctionType::get(Type::getInt32Ty(Context), /*not vararg*/false); 41 42 // By passing a module as the last parameter to the Function constructor, 43 // it automatically gets appended to the Module. 44 Function *F = Function::Create(FT, Function::ExternalLinkage, "main", M); 45 46 // Add a basic block to the function... again, it automatically inserts 47 // because of the last argument. 48 BasicBlock *BB = BasicBlock::Create(Context, "EntryBlock", F); 49 50 // Get pointers to the constant integers... 51 Value *Two = ConstantInt::get(Type::getInt32Ty(Context), 2); 52 Value *Three = ConstantInt::get(Type::getInt32Ty(Context), 3); 53 54 // Create the add instruction... does not insert... 55 Instruction *Add = BinaryOperator::Create(Instruction::Add, Two, Three, 56 "addresult"); 57 58 // explicitly insert it into the basic block... 59 BB->getInstList().push_back(Add); 60 61 // Create the return instruction and add it to the basic block 62 BB->getInstList().push_back(ReturnInst::Create(Context, Add)); 63 64 // Output the bitcode file to stdout 65 WriteBitcodeToFile(M, outs()); 66 67 // Delete the module and all of its contents. 68 delete M; 69 return 0; 70 } 71
