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