1 //===- AliasAnalysisEvaluator.cpp - Alias Analysis Accuracy Evaluator -----===//
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 a simple N^2 alias analysis accuracy evaluator.
11 // Basically, for each function in the program, it simply queries to see how the
12 // alias analysis implementation answers alias queries between each pair of
13 // pointers in the function.
15 // This is inspired and adapted from code by: Naveen Neelakantam, Francesco
16 // Spadini, and Wojciech Stryjewski.
18 //===----------------------------------------------------------------------===//
20 #include "llvm/Constants.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/Function.h"
23 #include "llvm/Instructions.h"
24 #include "llvm/Module.h"
25 #include "llvm/Pass.h"
26 #include "llvm/Analysis/Passes.h"
27 #include "llvm/Analysis/AliasAnalysis.h"
28 #include "llvm/Assembly/Writer.h"
29 #include "llvm/Support/Debug.h"
30 #include "llvm/Support/InstIterator.h"
31 #include "llvm/Support/CommandLine.h"
32 #include "llvm/Support/raw_ostream.h"
33 #include "llvm/ADT/SetVector.h"
36 static cl::opt<bool> PrintAll("print-all-alias-modref-info", cl::ReallyHidden);
38 static cl::opt<bool> PrintNoAlias("print-no-aliases", cl::ReallyHidden);
39 static cl::opt<bool> PrintMayAlias("print-may-aliases", cl::ReallyHidden);
40 static cl::opt<bool> PrintMustAlias("print-must-aliases", cl::ReallyHidden);
42 static cl::opt<bool> PrintNoModRef("print-no-modref", cl::ReallyHidden);
43 static cl::opt<bool> PrintMod("print-mod", cl::ReallyHidden);
44 static cl::opt<bool> PrintRef("print-ref", cl::ReallyHidden);
45 static cl::opt<bool> PrintModRef("print-modref", cl::ReallyHidden);
48 /// AAEval - Base class for exhaustive alias analysis evaluators.
51 unsigned NoAlias, MayAlias, MustAlias;
52 unsigned NoModRef, Mod, Ref, ModRef;
54 SetVector<Value *> Pointers;
55 SetVector<CallSite> CallSites;
57 void getAnalysisUsage(AnalysisUsage &AU) const {
58 AU.addRequired<AliasAnalysis>();
62 void doInitialization(Module &M) {
63 NoAlias = MayAlias = MustAlias = 0;
64 NoModRef = Mod = Ref = ModRef = 0;
67 PrintNoAlias = PrintMayAlias = PrintMustAlias = true;
68 PrintNoModRef = PrintMod = PrintRef = PrintModRef = true;
72 void runOnFunction(Function &F);
73 void evaluate(AliasAnalysis *AA, Module *M);
74 void doFinalization(Module &M);
77 class FunctionAAEval : public FunctionPass, AAEval {
79 static char ID; // Pass identification, replacement for typeid
80 FunctionAAEval() : FunctionPass(&ID) {}
82 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
83 return AAEval::getAnalysisUsage(AU);
86 virtual bool doInitialization(Module &M) {
87 AAEval::doInitialization(M);
91 virtual bool runOnFunction(Function &F) {
92 AAEval::runOnFunction(F);
94 if (PrintNoAlias || PrintMayAlias || PrintMustAlias ||
95 PrintNoModRef || PrintMod || PrintRef || PrintModRef)
96 errs() << "Function: " << F.getName() << ": " << Pointers.size()
97 << " pointers, " << CallSites.size() << " call sites\n";
99 AAEval::evaluate(&getAnalysis<AliasAnalysis>(), F.getParent());
103 virtual bool doFinalization(Module &M) {
104 AAEval::doFinalization(M);
109 class InterproceduralAAEval : public ModulePass, AAEval {
111 static char ID; // Pass identification, replacement for typeid
112 InterproceduralAAEval() : ModulePass(&ID) {}
114 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
115 return AAEval::getAnalysisUsage(AU);
118 virtual bool runOnModule(Module &M) {
119 AAEval::doInitialization(M);
120 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
121 AAEval::runOnFunction(*I);
123 if (PrintNoAlias || PrintMayAlias || PrintMustAlias ||
124 PrintNoModRef || PrintMod || PrintRef || PrintModRef)
125 errs() << "Module: " << Pointers.size()
126 << " pointers, " << CallSites.size() << " call sites\n";
128 AAEval::evaluate(&getAnalysis<AliasAnalysis>(), &M);
129 AAEval::doFinalization(M);
135 char FunctionAAEval::ID = 0;
136 static RegisterPass<FunctionAAEval>
137 X("aa-eval", "Exhaustive Alias Analysis Precision Evaluator", false, true);
139 FunctionPass *llvm::createAAEvalPass() { return new FunctionAAEval(); }
141 char InterproceduralAAEval::ID = 0;
142 static RegisterPass<InterproceduralAAEval>
143 Y("interprocedural-aa-eval",
144 "Exhaustive Interprocedural Alias Analysis Precision Evaluator", false, true);
146 Pass *llvm::createInterproceduralAAEvalPass() {
147 return new InterproceduralAAEval();
150 static void PrintResults(const char *Msg, bool P, const Value *V1,
151 const Value *V2, const Module *M) {
155 raw_string_ostream os1(o1), os2(o2);
156 WriteAsOperand(os1, V1, true, M);
157 WriteAsOperand(os2, V2, true, M);
162 errs() << " " << Msg << ":\t"
169 PrintModRefResults(const char *Msg, bool P, Instruction *I, Value *Ptr,
172 errs() << " " << Msg << ": Ptr: ";
173 WriteAsOperand(errs(), Ptr, true, M);
174 errs() << "\t<->" << *I << '\n';
178 static inline bool isInterestingPointer(Value *V) {
179 return V->getType()->isPointerTy()
180 && !isa<ConstantPointerNull>(V);
183 void AAEval::runOnFunction(Function &F) {
184 for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I)
185 if (I->getType()->isPointerTy()) // Add all pointer arguments.
188 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
189 if (I->getType()->isPointerTy()) // Add all pointer instructions.
190 Pointers.insert(&*I);
191 Instruction &Inst = *I;
192 CallSite CS = CallSite::get(&Inst);
194 Value *Callee = CS.getCalledValue();
195 // Skip actual functions for direct function calls.
196 if (!isa<Function>(Callee) && isInterestingPointer(Callee))
197 Pointers.insert(Callee);
199 for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
201 if (isInterestingPointer(*AI))
202 Pointers.insert(*AI);
204 // Consider all operands.
205 for (Instruction::op_iterator OI = Inst.op_begin(), OE = Inst.op_end();
207 if (isInterestingPointer(*OI))
208 Pointers.insert(*OI);
211 if (CS.getInstruction()) CallSites.insert(CS);
215 void AAEval::evaluate(AliasAnalysis *AA, Module *M) {
217 // iterate over the worklist, and run the full (n^2)/2 disambiguations
218 for (SetVector<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
220 unsigned I1Size = ~0u;
221 const Type *I1ElTy = cast<PointerType>((*I1)->getType())->getElementType();
222 if (I1ElTy->isSized()) I1Size = AA->getTypeStoreSize(I1ElTy);
224 for (SetVector<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2) {
225 unsigned I2Size = ~0u;
226 const Type *I2ElTy =cast<PointerType>((*I2)->getType())->getElementType();
227 if (I2ElTy->isSized()) I2Size = AA->getTypeStoreSize(I2ElTy);
229 switch (AA->alias(*I1, I1Size, *I2, I2Size)) {
230 case AliasAnalysis::NoAlias:
231 PrintResults("NoAlias", PrintNoAlias, *I1, *I2, M);
233 case AliasAnalysis::MayAlias:
234 PrintResults("MayAlias", PrintMayAlias, *I1, *I2, M);
236 case AliasAnalysis::MustAlias:
237 PrintResults("MustAlias", PrintMustAlias, *I1, *I2, M);
240 errs() << "Unknown alias query result!\n";
245 // Mod/ref alias analysis: compare all pairs of calls and values
246 for (SetVector<CallSite>::iterator C = CallSites.begin(),
247 Ce = CallSites.end(); C != Ce; ++C) {
248 Instruction *I = C->getInstruction();
250 for (SetVector<Value *>::iterator V = Pointers.begin(), Ve = Pointers.end();
253 const Type *ElTy = cast<PointerType>((*V)->getType())->getElementType();
254 if (ElTy->isSized()) Size = AA->getTypeStoreSize(ElTy);
256 switch (AA->getModRefInfo(*C, *V, Size)) {
257 case AliasAnalysis::NoModRef:
258 PrintModRefResults("NoModRef", PrintNoModRef, I, *V, M);
260 case AliasAnalysis::Mod:
261 PrintModRefResults(" Mod", PrintMod, I, *V, M);
263 case AliasAnalysis::Ref:
264 PrintModRefResults(" Ref", PrintRef, I, *V, M);
266 case AliasAnalysis::ModRef:
267 PrintModRefResults(" ModRef", PrintModRef, I, *V, M);
270 errs() << "Unknown alias query result!\n";
279 static void PrintPercent(unsigned Num, unsigned Sum) {
280 errs() << "(" << Num*100ULL/Sum << "."
281 << ((Num*1000ULL/Sum) % 10) << "%)\n";
284 void AAEval::doFinalization(Module &M) {
285 unsigned AliasSum = NoAlias + MayAlias + MustAlias;
286 errs() << "===== Alias Analysis Evaluator Report =====\n";
288 errs() << " Alias Analysis Evaluator Summary: No pointers!\n";
290 errs() << " " << AliasSum << " Total Alias Queries Performed\n";
291 errs() << " " << NoAlias << " no alias responses ";
292 PrintPercent(NoAlias, AliasSum);
293 errs() << " " << MayAlias << " may alias responses ";
294 PrintPercent(MayAlias, AliasSum);
295 errs() << " " << MustAlias << " must alias responses ";
296 PrintPercent(MustAlias, AliasSum);
297 errs() << " Alias Analysis Evaluator Pointer Alias Summary: "
298 << NoAlias*100/AliasSum << "%/" << MayAlias*100/AliasSum << "%/"
299 << MustAlias*100/AliasSum << "%\n";
302 // Display the summary for mod/ref analysis
303 unsigned ModRefSum = NoModRef + Mod + Ref + ModRef;
304 if (ModRefSum == 0) {
305 errs() << " Alias Analysis Mod/Ref Evaluator Summary: no mod/ref!\n";
307 errs() << " " << ModRefSum << " Total ModRef Queries Performed\n";
308 errs() << " " << NoModRef << " no mod/ref responses ";
309 PrintPercent(NoModRef, ModRefSum);
310 errs() << " " << Mod << " mod responses ";
311 PrintPercent(Mod, ModRefSum);
312 errs() << " " << Ref << " ref responses ";
313 PrintPercent(Ref, ModRefSum);
314 errs() << " " << ModRef << " mod & ref responses ";
315 PrintPercent(ModRef, ModRefSum);
316 errs() << " Alias Analysis Evaluator Mod/Ref Summary: "
317 << NoModRef*100/ModRefSum << "%/" << Mod*100/ModRefSum << "%/"
318 << Ref*100/ModRefSum << "%/" << ModRef*100/ModRefSum << "%\n";