LLVM API Documentation
00001 //===- Hello.cpp - Example code from "Writing an LLVM Pass" ---------------===// 00002 // 00003 // The LLVM Compiler Infrastructure 00004 // 00005 // This file was developed by the LLVM research group and is distributed under 00006 // the University of Illinois Open Source License. See LICENSE.TXT for details. 00007 // 00008 //===----------------------------------------------------------------------===// 00009 // 00010 // This file implements two versions of the LLVM "Hello World" pass described 00011 // in docs/WritingAnLLVMPass.html 00012 // 00013 //===----------------------------------------------------------------------===// 00014 00015 #include "llvm/Pass.h" 00016 #include "llvm/Function.h" 00017 #include <iostream> 00018 using namespace llvm; 00019 00020 namespace { 00021 // Hello - The first implementation, without getAnalysisUsage. 00022 struct Hello : public FunctionPass { 00023 virtual bool runOnFunction(Function &F) { 00024 std::cerr << "Hello: " << F.getName() << "\n"; 00025 return false; 00026 } 00027 }; 00028 RegisterOpt<Hello> X("hello", "Hello World Pass"); 00029 00030 // Hello2 - The second implementation with getAnalysisUsage implemented. 00031 struct Hello2 : public FunctionPass { 00032 virtual bool runOnFunction(Function &F) { 00033 std::cerr << "Hello: " << F.getName() << "\n"; 00034 return false; 00035 } 00036 00037 // We don't modify the program, so we preserve all analyses 00038 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 00039 AU.setPreservesAll(); 00040 }; 00041 }; 00042 RegisterOpt<Hello2> Y("hello2", "Hello World Pass (with getAnalysisUsage implemented)"); 00043 }