1//===- AliasAnalysisCounter.cpp - Alias Analysis Query Counter ------------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements a pass which can be used to count how many alias queries
11// are being made and how the alias analysis implementation being used responds.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/Analysis/Passes.h"
16#include "llvm/Pass.h"
17#include "llvm/Analysis/AliasAnalysis.h"
18#include "llvm/Assembly/Writer.h"
19#include "llvm/Support/CommandLine.h"
20#include "llvm/Support/Compiler.h"
21#include "llvm/Support/ErrorHandling.h"
22#include "llvm/Support/raw_ostream.h"
23using namespace llvm;
24
25static cl::opt<bool>
26PrintAll("count-aa-print-all-queries", cl::ReallyHidden, cl::init(true));
27static cl::opt<bool>
28PrintAllFailures("count-aa-print-all-failed-queries", cl::ReallyHidden);
29
30namespace {
31 class VISIBILITY_HIDDEN AliasAnalysisCounter
32 : public ModulePass, public AliasAnalysis {
33 unsigned No, May, Must;
34 unsigned NoMR, JustRef, JustMod, MR;
35 const char *Name;
36 Module *M;
37 public:
38 static char ID; // Class identification, replacement for typeinfo
39 AliasAnalysisCounter() : ModulePass(&ID) {
40 No = May = Must = 0;
41 NoMR = JustRef = JustMod = MR = 0;
42 }
43
44 void printLine(const char *Desc, unsigned Val, unsigned Sum) {
45 errs() << " " << Val << " " << Desc << " responses ("
46 << Val*100/Sum << "%)\n";
47 }
48 ~AliasAnalysisCounter() {
49 unsigned AASum = No+May+Must;
50 unsigned MRSum = NoMR+JustRef+JustMod+MR;
51 if (AASum + MRSum) { // Print a report if any counted queries occurred...
52 errs() << "\n===== Alias Analysis Counter Report =====\n"
53 << " Analysis counted: " << Name << "\n"
54 << " " << AASum << " Total Alias Queries Performed\n";
55 if (AASum) {
56 printLine("no alias", No, AASum);
57 printLine("may alias", May, AASum);
58 printLine("must alias", Must, AASum);
59 errs() << " Alias Analysis Counter Summary: " << No*100/AASum << "%/"
60 << May*100/AASum << "%/" << Must*100/AASum<<"%\n\n";
61 }
62
63 errs() << " " << MRSum << " Total Mod/Ref Queries Performed\n";
64 if (MRSum) {
65 printLine("no mod/ref", NoMR, MRSum);
66 printLine("ref", JustRef, MRSum);
67 printLine("mod", JustMod, MRSum);
68 printLine("mod/ref", MR, MRSum);
69 errs() << " Mod/Ref Analysis Counter Summary: " <<NoMR*100/MRSum
70 << "%/" << JustRef*100/MRSum << "%/" << JustMod*100/MRSum
71 << "%/" << MR*100/MRSum <<"%\n\n";
72 }
73 }
74 }
75
76 bool runOnModule(Module &M) {
77 this->M = &M;
78 InitializeAliasAnalysis(this);
79 Name = dynamic_cast<Pass*>(&getAnalysis<AliasAnalysis>())->getPassName();
80 return false;
81 }
82
83 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
84 AliasAnalysis::getAnalysisUsage(AU);
85 AU.addRequired<AliasAnalysis>();
86 AU.setPreservesAll();
87 }
88
89 // FIXME: We could count these too...
90 bool pointsToConstantMemory(const Value *P) {
91 return getAnalysis<AliasAnalysis>().pointsToConstantMemory(P);
92 }
93
94 // Forwarding functions: just delegate to a real AA implementation, counting
95 // the number of responses...
96 AliasResult alias(const Value *V1, unsigned V1Size,
97 const Value *V2, unsigned V2Size);
98
99 ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size);
100 ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) {
101 return AliasAnalysis::getModRefInfo(CS1,CS2);
102 }
103 };
104}
105
106char AliasAnalysisCounter::ID = 0;
107static RegisterPass<AliasAnalysisCounter>
108X("count-aa", "Count Alias Analysis Query Responses", false, true);
109static RegisterAnalysisGroup<AliasAnalysis> Y(X);
110
111ModulePass *llvm::createAliasAnalysisCounterPass() {
112 return new AliasAnalysisCounter();
113}
114
115AliasAnalysis::AliasResult
116AliasAnalysisCounter::alias(const Value *V1, unsigned V1Size,
117 const Value *V2, unsigned V2Size) {
118 AliasResult R = getAnalysis<AliasAnalysis>().alias(V1, V1Size, V2, V2Size);
119
120 const char *AliasString;
121 switch (R) {
122 default: llvm_unreachable("Unknown alias type!");
123 case NoAlias: No++; AliasString = "No alias"; break;
124 case MayAlias: May++; AliasString = "May alias"; break;
125 case MustAlias: Must++; AliasString = "Must alias"; break;
126 }
127
128 if (PrintAll || (PrintAllFailures && R == MayAlias)) {
129 errs() << AliasString << ":\t";
130 errs() << "[" << V1Size << "B] ";
131 WriteAsOperand(errs(), V1, true, M);
132 errs() << ", ";
133 errs() << "[" << V2Size << "B] ";
134 WriteAsOperand(errs(), V2, true, M);
135 errs() << "\n";
136 }
137
138 return R;
139}
140
141AliasAnalysis::ModRefResult
142AliasAnalysisCounter::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
143 ModRefResult R = getAnalysis<AliasAnalysis>().getModRefInfo(CS, P, Size);
144
145 const char *MRString;
146 switch (R) {
147 default: llvm_unreachable("Unknown mod/ref type!");
148 case NoModRef: NoMR++; MRString = "NoModRef"; break;
149 case Ref: JustRef++; MRString = "JustRef"; break;
150 case Mod: JustMod++; MRString = "JustMod"; break;
151 case ModRef: MR++; MRString = "ModRef"; break;
152 }
153
154 if (PrintAll || (PrintAllFailures && R == ModRef)) {
155 errs() << MRString << ": Ptr: ";
156 errs() << "[" << Size << "B] ";
157 WriteAsOperand(errs(), P, true, M);
158 errs() << "\t<->" << *CS.getInstruction();
159 }
160 return R;
161}