1 //===- MetaRenamer.cpp - Rename everything with metasyntatic names --------===//
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 pass renames everything with metasyntatic names. The intent is to use
11 // this pass after bugpoint reduction to conceal the nature of the original
14 //===----------------------------------------------------------------------===//
16 #include "llvm/Transforms/IPO.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/SmallString.h"
19 #include "llvm/IR/DerivedTypes.h"
20 #include "llvm/IR/Function.h"
21 #include "llvm/IR/Module.h"
22 #include "llvm/IR/Type.h"
23 #include "llvm/IR/TypeFinder.h"
24 #include "llvm/Pass.h"
29 // This PRNG is from the ISO C spec. It is intentionally simple and
30 // unsuitable for cryptographic use. We're just looking for enough
31 // variety to surprise and delight users.
35 void srand(unsigned int seed) {
40 next = next * 1103515245 + 12345;
41 return (unsigned int)(next / 65536) % 32768;
45 static const char *const metaNames[] = {
46 // See http://en.wikipedia.org/wiki/Metasyntactic_variable
47 "foo", "bar", "baz", "quux", "barney", "snork", "zot", "blam", "hoge",
48 "wibble", "wobble", "widget", "wombat", "ham", "eggs", "pluto", "spam"
52 Renamer(unsigned int seed) {
56 const char *newName() {
57 return metaNames[prng.rand() % array_lengthof(metaNames)];
63 struct MetaRenamer : public ModulePass {
64 static char ID; // Pass identification, replacement for typeid
65 MetaRenamer() : ModulePass(ID) {
66 initializeMetaRenamerPass(*PassRegistry::getPassRegistry());
69 void getAnalysisUsage(AnalysisUsage &AU) const override {
73 bool runOnModule(Module &M) override {
74 // Seed our PRNG with simple additive sum of ModuleID. We're looking to
75 // simply avoid always having the same function names, and we need to
76 // remain deterministic.
77 unsigned int randSeed = 0;
78 for (std::string::const_iterator I = M.getModuleIdentifier().begin(),
79 E = M.getModuleIdentifier().end(); I != E; ++I)
82 Renamer renamer(randSeed);
85 for (Module::alias_iterator AI = M.alias_begin(), AE = M.alias_end();
87 StringRef Name = AI->getName();
88 if (Name.startswith("llvm.") || (!Name.empty() && Name[0] == 1))
94 // Rename all global variables
95 for (Module::global_iterator GI = M.global_begin(), GE = M.global_end();
97 StringRef Name = GI->getName();
98 if (Name.startswith("llvm.") || (!Name.empty() && Name[0] == 1))
101 GI->setName("global");
104 // Rename all struct types
105 TypeFinder StructTypes;
106 StructTypes.run(M, true);
107 for (unsigned i = 0, e = StructTypes.size(); i != e; ++i) {
108 StructType *STy = StructTypes[i];
109 if (STy->isLiteral() || STy->getName().empty()) continue;
111 SmallString<128> NameStorage;
112 STy->setName((Twine("struct.") +
113 renamer.newName()).toStringRef(NameStorage));
116 // Rename all functions
117 for (Module::iterator FI = M.begin(), FE = M.end();
119 StringRef Name = FI->getName();
120 if (Name.startswith("llvm.") || (!Name.empty() && Name[0] == 1))
123 FI->setName(renamer.newName());
129 bool runOnFunction(Function &F) {
130 for (Function::arg_iterator AI = F.arg_begin(), AE = F.arg_end();
132 if (!AI->getType()->isVoidTy())
135 for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
138 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
139 if (!I->getType()->isVoidTy())
147 char MetaRenamer::ID = 0;
148 INITIALIZE_PASS(MetaRenamer, "metarenamer",
149 "Assign new names to everything", false, false)
150 //===----------------------------------------------------------------------===//
152 // MetaRenamer - Rename everything with metasyntactic names.
154 ModulePass *llvm::createMetaRenamerPass() {
155 return new MetaRenamer();