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// RUN: %cxx `%llvm-config --cxxflags` -fPIC -shared %s -o Hello.so
// RUN: %opt -load ./Hello.so -help | grep "Hello World Pass"
// REQUIRES: opt, llvm-config
//===- Hello.cpp - Example code from "Writing an LLVM Pass" ---------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements two versions of the LLVM "Hello World" pass described
// in docs/WritingAnLLVMPass.html
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/Statistic.h"
#include "llvm/IR/Function.h"
#include "llvm/Pass.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "hello"
STATISTIC(HelloCounter, "Counts number of functions greeted");
namespace {
// Hello - The first implementation, without getAnalysisUsage.
struct Hello : public FunctionPass {
static char ID; // Pass identification, replacement for typeid
Hello() : FunctionPass(ID) {}
bool runOnFunction(Function &F) override {
++HelloCounter;
errs() << "Hello: ";
errs().write_escaped(F.getName()) << '\n';
return false;
}
};
}
char Hello::ID = 0;
static RegisterPass<Hello> X("hello", "Hello World Pass");
namespace {
// Hello2 - The second implementation with getAnalysisUsage implemented.
struct Hello2 : public FunctionPass {
static char ID; // Pass identification, replacement for typeid
Hello2() : FunctionPass(ID) {}
bool runOnFunction(Function &F) override {
++HelloCounter;
errs() << "Hello: ";
errs().write_escaped(F.getName()) << '\n';
return false;
}
// We don't modify the program, so we preserve all analyses.
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
}
};
}
char Hello2::ID = 0;
static RegisterPass<Hello2>
Y("hello2", "Hello World Pass (with getAnalysisUsage implemented)");
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