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/iOther.h"
22 #include "llvm/iTerminators.h"
23 #include "llvm/Pass.h"
24 #include "llvm/Type.h"
25 #include "llvm/Analysis/AliasAnalysis.h"
26 #include "llvm/Assembly/Writer.h"
27 #include "llvm/Support/InstIterator.h"
28 #include "Support/CommandLine.h"
33 cl::opt<bool> PrintNoAlias("print-no-aliases", cl::ReallyHidden);
34 cl::opt<bool> PrintMayAlias("print-may-aliases", cl::ReallyHidden);
35 cl::opt<bool> PrintMustAlias("print-must-aliases", cl::ReallyHidden);
37 cl::opt<bool> PrintNoModRef("print-no-modref", cl::ReallyHidden);
38 cl::opt<bool> PrintMod("print-mod", cl::ReallyHidden);
39 cl::opt<bool> PrintRef("print-ref", cl::ReallyHidden);
40 cl::opt<bool> PrintModRef("print-modref", cl::ReallyHidden);
42 class AAEval : public FunctionPass {
43 unsigned NoAlias, MayAlias, MustAlias;
44 unsigned NoModRef, Mod, Ref, ModRef;
47 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
48 AU.addRequired<AliasAnalysis>();
52 bool doInitialization(Module &M) {
53 NoAlias = MayAlias = MustAlias = 0;
54 NoModRef = Mod = Ref = ModRef = 0;
58 bool runOnFunction(Function &F);
59 bool doFinalization(Module &M);
63 X("aa-eval", "Exhaustive Alias Analysis Precision Evaluator");
66 static inline void PrintResults(const char *Msg, bool P, Value *V1, Value *V2,
69 std::cerr << " " << Msg << ":\t";
70 WriteAsOperand(std::cerr, V1, true, true, M) << ", ";
71 WriteAsOperand(std::cerr, V2, true, true, M) << "\n";
75 bool AAEval::runOnFunction(Function &F) {
76 AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
78 std::set<Value *> Pointers;
79 std::set<CallSite> CallSites;
81 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I)
82 if (isa<PointerType>(I->getType())) // Add all pointer arguments
85 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
86 if (isa<PointerType>((*I)->getType())) // Add all pointer instructions
88 for (User::op_iterator OI = (*I)->op_begin(); OI != (*I)->op_end(); ++OI)
89 if (isa<PointerType>((*OI)->getType()))
93 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
94 CallSite CS = CallSite::get(*I);
95 if (CS.getInstruction()) CallSites.insert(CS);
98 if (PrintNoAlias || PrintMayAlias || PrintMustAlias ||
99 PrintNoModRef || PrintMod || PrintRef || PrintModRef)
100 std::cerr << "Function: " << F.getName() << "\n";
102 // iterate over the worklist, and run the full (n^2)/2 disambiguations
103 for (std::set<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
105 for (std::set<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2)
106 switch (AA.alias(*I1, 0, *I2, 0)) {
107 case AliasAnalysis::NoAlias:
108 PrintResults("NoAlias", PrintNoAlias, *I1, *I2, F.getParent());
110 case AliasAnalysis::MayAlias:
111 PrintResults("MayAlias", PrintMayAlias, *I1, *I2, F.getParent());
113 case AliasAnalysis::MustAlias:
114 PrintResults("MustAlias", PrintMustAlias, *I1, *I2, F.getParent());
117 std::cerr << "Unknown alias query result!\n";
120 // Mod/ref alias analysis: compare all pairs of calls and values
121 for (std::set<Value *>::iterator V = Pointers.begin(), Ve = Pointers.end();
123 for (std::set<CallSite>::iterator C = CallSites.begin(),
124 Ce = CallSites.end(); C != Ce; ++C) {
125 Instruction *I = C->getInstruction();
126 switch (AA.getModRefInfo(*C, *V, (*V)->getType()->getPrimitiveSize())) {
127 case AliasAnalysis::NoModRef:
128 PrintResults("NoModRef", PrintNoModRef, I, *V, F.getParent());
130 case AliasAnalysis::Mod:
131 PrintResults("Mod", PrintMod, I, *V, F.getParent());
133 case AliasAnalysis::Ref:
134 PrintResults("Ref", PrintRef, I, *V, F.getParent());
136 case AliasAnalysis::ModRef:
137 PrintResults("ModRef", PrintModRef, I, *V, F.getParent());
140 std::cerr << "Unknown alias query result!\n";
147 bool AAEval::doFinalization(Module &M) {
148 unsigned AliasSum = NoAlias + MayAlias + MustAlias;
149 std::cerr << "===== Alias Analysis Evaluator Report =====\n";
151 std::cerr << " Alias Analysis Evaluator Summary: No pointers!\n";
153 std::cerr << " " << AliasSum << " Total Alias Queries Performed\n";
154 std::cerr << " " << NoAlias << " no alias responses ("
155 << NoAlias*100/AliasSum << "%)\n";
156 std::cerr << " " << MayAlias << " may alias responses ("
157 << MayAlias*100/AliasSum << "%)\n";
158 std::cerr << " " << MustAlias << " must alias responses ("
159 << MustAlias*100/AliasSum <<"%)\n";
160 std::cerr << " Alias Analysis Evaluator Pointer Alias Summary: "
161 << NoAlias*100/AliasSum << "%/" << MayAlias*100/AliasSum << "%/"
162 << MustAlias*100/AliasSum << "%\n";
165 // Display the summary for mod/ref analysis
166 unsigned ModRefSum = NoModRef + Mod + Ref + ModRef;
167 if (ModRefSum == 0) {
168 std::cerr << " Alias Analysis Mod/Ref Evaluator Summary: no mod/ref!\n";
170 std::cerr << " " << ModRefSum << " Total ModRef Queries Performed\n";
171 std::cerr << " " << NoModRef << " no mod/ref responses ("
172 << NoModRef*100/ModRefSum << "%)\n";
173 std::cerr << " " << Mod << " mod responses ("
174 << Mod*100/ModRefSum << "%)\n";
175 std::cerr << " " << Ref << " ref responses ("
176 << Ref*100/ModRefSum <<"%)\n";
177 std::cerr << " " << ModRef << " mod & ref responses ("
178 << ModRef*100/ModRefSum <<"%)\n";
179 std::cerr << " Alias Analysis Evaluator Mod/Ref Summary: "
180 << NoModRef*100/ModRefSum << "%/" << Mod*100/ModRefSum << "%/"
181 << Ref*100/ModRefSum << "%/" << ModRef*100/ModRefSum << "%\n";