1 //===- Hello.cpp - Example code from "Writing an LLVM Pass" ---------------===//
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 file implements two versions of the LLVM "Hello World" pass described
11 // in docs/WritingAnLLVMPass.html
13 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "hello"
16 #include "llvm/ADT/Statistic.h"
17 #include "llvm/IR/Function.h"
18 #include "llvm/Pass.h"
19 #include "llvm/Support/raw_ostream.h"
22 STATISTIC(HelloCounter, "Counts number of functions greeted");
25 // Hello - The first implementation, without getAnalysisUsage.
26 struct Hello : public FunctionPass {
27 static char ID; // Pass identification, replacement for typeid
28 Hello() : FunctionPass(ID) {}
30 virtual bool runOnFunction(Function &F) {
33 errs().write_escaped(F.getName()) << '\n';
40 static RegisterPass<Hello> X("hello", "Hello World Pass");
43 // Hello2 - The second implementation with getAnalysisUsage implemented.
44 struct Hello2 : public FunctionPass {
45 static char ID; // Pass identification, replacement for typeid
46 Hello2() : FunctionPass(ID) {}
48 virtual bool runOnFunction(Function &F) {
51 errs().write_escaped(F.getName()) << '\n';
55 // We don't modify the program, so we preserve all analyses.
56 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
63 static RegisterPass<Hello2>
64 Y("hello2", "Hello World Pass (with getAnalysisUsage implemented)");