1 //===- examples/ModuleMaker/ModuleMaker.cpp - Example project ---*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
14 //===----------------------------------------------------------------------===//
16 #include "llvm/Module.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Constants.h"
19 #include "llvm/Instructions.h"
20 #include "llvm/Bitcode/ReaderWriter.h"
25 // Create the "module" or "program" or "translation unit" to hold the
27 Module *M = new Module("test");
29 // Create the main function: first create the type 'int ()'
30 FunctionType *FT = FunctionType::get(Type::Int32Ty, /*not vararg*/false);
32 // By passing a module as the last parameter to the Function constructor,
33 // it automatically gets appended to the Module.
34 Function *F = Function::Create(FT, Function::ExternalLinkage, "main", M);
36 // Add a basic block to the function... again, it automatically inserts
37 // because of the last argument.
38 BasicBlock *BB = BasicBlock::Create("EntryBlock", F);
40 // Get pointers to the constant integers...
41 Value *Two = ConstantInt::get(Type::Int32Ty, 2);
42 Value *Three = ConstantInt::get(Type::Int32Ty, 3);
44 // Create the add instruction... does not insert...
45 Instruction *Add = BinaryOperator::Create(Instruction::Add, Two, Three,
48 // explicitly insert it into the basic block...
49 BB->getInstList().push_back(Add);
51 // Create the return instruction and add it to the basic block
52 BB->getInstList().push_back(ReturnInst::Create(Add));
54 // Output the bitcode file to stdout
55 WriteBitcodeToFile(M, std::cout);
57 // Delete the module and all of its contents.