ModuleMaker.cpp revision 66e7cd0eea6f116f3ed79acb8948c6d8db50833c 
1//===- examples/ModuleMaker/ModuleMaker.cpp - Example project ---*- 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
16using namespace llvm;
17
18int 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