1 //===- AliasAnalysisEvaluator.cpp - Alias Analysis Accuracy Evaluator -----===//
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 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/Function.h"
21 #include "llvm/Instructions.h"
22 #include "llvm/Pass.h"
23 #include "llvm/DerivedTypes.h"
24 #include "llvm/Analysis/Passes.h"
25 #include "llvm/Analysis/AliasAnalysis.h"
26 #include "llvm/Assembly/Writer.h"
27 #include "llvm/Target/TargetData.h"
28 #include "llvm/Support/InstIterator.h"
29 #include "llvm/Support/CommandLine.h"
36 cl::opt<bool> PrintAll("print-all-alias-modref-info", cl::ReallyHidden);
38 cl::opt<bool> PrintNoAlias("print-no-aliases", cl::ReallyHidden);
39 cl::opt<bool> PrintMayAlias("print-may-aliases", cl::ReallyHidden);
40 cl::opt<bool> PrintMustAlias("print-must-aliases", cl::ReallyHidden);
42 cl::opt<bool> PrintNoModRef("print-no-modref", cl::ReallyHidden);
43 cl::opt<bool> PrintMod("print-mod", cl::ReallyHidden);
44 cl::opt<bool> PrintRef("print-ref", cl::ReallyHidden);
45 cl::opt<bool> PrintModRef("print-modref", cl::ReallyHidden);
47 class AAEval : public FunctionPass {
48 unsigned NoAlias, MayAlias, MustAlias;
49 unsigned NoModRef, Mod, Ref, ModRef;
52 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
53 AU.addRequired<AliasAnalysis>();
57 bool doInitialization(Module &M) {
58 NoAlias = MayAlias = MustAlias = 0;
59 NoModRef = Mod = Ref = ModRef = 0;
62 PrintNoAlias = PrintMayAlias = PrintMustAlias = true;
63 PrintNoModRef = PrintMod = PrintRef = PrintModRef = true;
68 bool runOnFunction(Function &F);
69 bool doFinalization(Module &M);
73 X("aa-eval", "Exhaustive Alias Analysis Precision Evaluator");
76 FunctionPass *llvm::createAAEvalPass() { return new AAEval(); }
78 static inline void PrintResults(const char *Msg, bool P, Value *V1, Value *V2,
81 std::cerr << " " << Msg << ":\t";
82 WriteAsOperand(std::cerr, V1, true, true, M) << ", ";
83 WriteAsOperand(std::cerr, V2, true, true, M) << "\n";
88 PrintModRefResults(const char *Msg, bool P, Instruction *I, Value *Ptr,
91 std::cerr << " " << Msg << ": Ptr: ";
92 WriteAsOperand(std::cerr, Ptr, true, true, M);
93 std::cerr << "\t<->" << *I;
97 bool AAEval::runOnFunction(Function &F) {
98 AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
100 const TargetData &TD = AA.getTargetData();
102 std::set<Value *> Pointers;
103 std::set<CallSite> CallSites;
105 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I)
106 if (isa<PointerType>(I->getType())) // Add all pointer arguments
109 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
110 if (isa<PointerType>(I->getType())) // Add all pointer instructions
111 Pointers.insert(&*I);
112 for (User::op_iterator OI = (*I).op_begin(); OI != (*I).op_end(); ++OI)
113 if (isa<PointerType>((*OI)->getType()))
114 Pointers.insert(*OI);
116 CallSite CS = CallSite::get(&*I);
117 if (CS.getInstruction()) CallSites.insert(CS);
120 if (PrintNoAlias || PrintMayAlias || PrintMustAlias ||
121 PrintNoModRef || PrintMod || PrintRef || PrintModRef)
122 std::cerr << "Function: " << F.getName() << ": " << Pointers.size()
123 << " pointers, " << CallSites.size() << " call sites\n";
125 // iterate over the worklist, and run the full (n^2)/2 disambiguations
126 for (std::set<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
129 const Type *I1ElTy = cast<PointerType>((*I1)->getType())->getElementType();
130 if (I1ElTy->isSized()) I1Size = TD.getTypeSize(I1ElTy);
132 for (std::set<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2) {
134 const Type *I2ElTy =cast<PointerType>((*I2)->getType())->getElementType();
135 if (I2ElTy->isSized()) I2Size = TD.getTypeSize(I2ElTy);
137 switch (AA.alias(*I1, I1Size, *I2, I2Size)) {
138 case AliasAnalysis::NoAlias:
139 PrintResults("NoAlias", PrintNoAlias, *I1, *I2, F.getParent());
141 case AliasAnalysis::MayAlias:
142 PrintResults("MayAlias", PrintMayAlias, *I1, *I2, F.getParent());
144 case AliasAnalysis::MustAlias:
145 PrintResults("MustAlias", PrintMustAlias, *I1, *I2, F.getParent());
148 std::cerr << "Unknown alias query result!\n";
153 // Mod/ref alias analysis: compare all pairs of calls and values
154 for (std::set<Value *>::iterator V = Pointers.begin(), Ve = Pointers.end();
157 const Type *ElTy = cast<PointerType>((*V)->getType())->getElementType();
158 if (ElTy->isSized()) Size = TD.getTypeSize(ElTy);
160 for (std::set<CallSite>::iterator C = CallSites.begin(),
161 Ce = CallSites.end(); C != Ce; ++C) {
162 Instruction *I = C->getInstruction();
163 switch (AA.getModRefInfo(*C, *V, Size)) {
164 case AliasAnalysis::NoModRef:
165 PrintModRefResults("NoModRef", PrintNoModRef, I, *V, F.getParent());
167 case AliasAnalysis::Mod:
168 PrintModRefResults(" Mod", PrintMod, I, *V, F.getParent());
170 case AliasAnalysis::Ref:
171 PrintModRefResults(" Ref", PrintRef, I, *V, F.getParent());
173 case AliasAnalysis::ModRef:
174 PrintModRefResults(" ModRef", PrintModRef, I, *V, F.getParent());
177 std::cerr << "Unknown alias query result!\n";
185 bool AAEval::doFinalization(Module &M) {
186 unsigned AliasSum = NoAlias + MayAlias + MustAlias;
187 std::cerr << "===== Alias Analysis Evaluator Report =====\n";
189 std::cerr << " Alias Analysis Evaluator Summary: No pointers!\n";
191 std::cerr << " " << AliasSum << " Total Alias Queries Performed\n";
192 std::cerr << " " << NoAlias << " no alias responses ("
193 << NoAlias*100/AliasSum << "%)\n";
194 std::cerr << " " << MayAlias << " may alias responses ("
195 << MayAlias*100/AliasSum << "%)\n";
196 std::cerr << " " << MustAlias << " must alias responses ("
197 << MustAlias*100/AliasSum <<"%)\n";
198 std::cerr << " Alias Analysis Evaluator Pointer Alias Summary: "
199 << NoAlias*100/AliasSum << "%/" << MayAlias*100/AliasSum << "%/"
200 << MustAlias*100/AliasSum << "%\n";
203 // Display the summary for mod/ref analysis
204 unsigned ModRefSum = NoModRef + Mod + Ref + ModRef;
205 if (ModRefSum == 0) {
206 std::cerr << " Alias Analysis Mod/Ref Evaluator Summary: no mod/ref!\n";
208 std::cerr << " " << ModRefSum << " Total ModRef Queries Performed\n";
209 std::cerr << " " << NoModRef << " no mod/ref responses ("
210 << NoModRef*100/ModRefSum << "%)\n";
211 std::cerr << " " << Mod << " mod responses ("
212 << Mod*100/ModRefSum << "%)\n";
213 std::cerr << " " << Ref << " ref responses ("
214 << Ref*100/ModRefSum <<"%)\n";
215 std::cerr << " " << ModRef << " mod & ref responses ("
216 << ModRef*100/ModRefSum <<"%)\n";
217 std::cerr << " Alias Analysis Evaluator Mod/Ref Summary: "
218 << NoModRef*100/ModRefSum << "%/" << Mod*100/ModRefSum << "%/"
219 << Ref*100/ModRefSum << "%/" << ModRef*100/ModRefSum << "%\n";