1 //===- Hello.cpp - Example code from "Writing an LLVM Pass" ---------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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 #include "llvm/Pass.h"
16 #include "llvm/Function.h"
17 #include "llvm/ADT/StringExtras.h"
18 #include "llvm/Support/SlowOperationInformer.h"
19 #include "llvm/Support/Streams.h"
20 #include "llvm/ADT/Statistic.h"
24 Statistic HelloCounter("hellocount",
25 "Counts number of functions greeted");
26 // Hello - The first implementation, without getAnalysisUsage.
27 struct Hello : public FunctionPass {
28 virtual bool runOnFunction(Function &F) {
29 SlowOperationInformer soi("EscapeString");
31 std::string fname = F.getName();
33 llvm_cerr << "Hello: " << fname << "\n";
37 RegisterPass<Hello> X("hello", "Hello World Pass");
39 // Hello2 - The second implementation with getAnalysisUsage implemented.
40 struct Hello2 : public FunctionPass {
41 virtual bool runOnFunction(Function &F) {
42 SlowOperationInformer soi("EscapeString");
44 std::string fname = F.getName();
46 llvm_cerr << "Hello: " << fname << "\n";
50 // We don't modify the program, so we preserve all analyses
51 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
55 RegisterPass<Hello2> Y("hello2",
56 "Hello World Pass (with getAnalysisUsage implemented)");