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 "llvm/Support/raw_ostream.h" 23 using namespace llvm; 24 25 int 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 = 34 FunctionType::get(Type::getInt32Ty(Context), /*not vararg*/false); 35 36 // By passing a module as the last parameter to the Function constructor, 37 // it automatically gets appended to the Module. 38 Function *F = Function::Create(FT, Function::ExternalLinkage, "main", M); 39 40 // Add a basic block to the function... again, it automatically inserts 41 // because of the last argument. 42 BasicBlock *BB = BasicBlock::Create(Context, "EntryBlock", F); 43 44 // Get pointers to the constant integers... 45 Value *Two = ConstantInt::get(Type::getInt32Ty(Context), 2); 46 Value *Three = ConstantInt::get(Type::getInt32Ty(Context), 3); 47 48 // Create the add instruction... does not insert... 49 Instruction *Add = BinaryOperator::Create(Instruction::Add, Two, Three, 50 "addresult"); 51 52 // explicitly insert it into the basic block... 53 BB->getInstList().push_back(Add); 54 55 // Create the return instruction and add it to the basic block 56 BB->getInstList().push_back(ReturnInst::Create(Context, Add)); 57 58 // Output the bitcode file to stdout 59 WriteBitcodeToFile(M, outs()); 60 61 // Delete the module and all of its contents. 62 delete M; 63 return 0; 64 } 65
