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/Analysis/AliasAnalysis.h"
17 #include "llvm/Pass.h"
18 #include "llvm/Support/CommandLine.h"
19 #include "llvm/Support/Debug.h"
20 #include "llvm/Support/ErrorHandling.h"
21 #include "llvm/Support/raw_ostream.h"
22 using namespace llvm;
23
24 static cl::opt<bool>
25 PrintAll("count-aa-print-all-queries", cl::ReallyHidden, cl::init(true));
26 static cl::opt<bool>
27 PrintAllFailures("count-aa-print-all-failed-queries", cl::ReallyHidden);
28
29 namespace {
30 class AliasAnalysisCounter : public ModulePass, public AliasAnalysis {
31 unsigned No, May, Partial, Must;
32 unsigned NoMR, JustRef, JustMod, MR;
33 Module *M;
34 public:
35 static char ID; // Class identification, replacement for typeinfo
AliasAnalysisCounter()36 AliasAnalysisCounter() : ModulePass(ID) {
37 initializeAliasAnalysisCounterPass(*PassRegistry::getPassRegistry());
38 No = May = Partial = Must = 0;
39 NoMR = JustRef = JustMod = MR = 0;
40 }
41
printLine(const char * Desc,unsigned Val,unsigned Sum)42 void printLine(const char *Desc, unsigned Val, unsigned Sum) {
43 errs() << " " << Val << " " << Desc << " responses ("
44 << Val*100/Sum << "%)\n";
45 }
~AliasAnalysisCounter()46 ~AliasAnalysisCounter() {
47 unsigned AASum = No+May+Partial+Must;
48 unsigned MRSum = NoMR+JustRef+JustMod+MR;
49 if (AASum + MRSum) { // Print a report if any counted queries occurred...
50 errs() << "\n===== Alias Analysis Counter Report =====\n"
51 << " Analysis counted:\n"
52 << " " << AASum << " Total Alias Queries Performed\n";
53 if (AASum) {
54 printLine("no alias", No, AASum);
55 printLine("may alias", May, AASum);
56 printLine("partial alias", Partial, AASum);
57 printLine("must alias", Must, AASum);
58 errs() << " Alias Analysis Counter Summary: " << No*100/AASum << "%/"
59 << May*100/AASum << "%/"
60 << Partial*100/AASum << "%/"
61 << Must*100/AASum<<"%\n\n";
62 }
63
64 errs() << " " << MRSum << " Total Mod/Ref Queries Performed\n";
65 if (MRSum) {
66 printLine("no mod/ref", NoMR, MRSum);
67 printLine("ref", JustRef, MRSum);
68 printLine("mod", JustMod, MRSum);
69 printLine("mod/ref", MR, MRSum);
70 errs() << " Mod/Ref Analysis Counter Summary: " <<NoMR*100/MRSum
71 << "%/" << JustRef*100/MRSum << "%/" << JustMod*100/MRSum
72 << "%/" << MR*100/MRSum <<"%\n\n";
73 }
74 }
75 }
76
runOnModule(Module & M)77 bool runOnModule(Module &M) override {
78 this->M = &M;
79 InitializeAliasAnalysis(this);
80 return false;
81 }
82
getAnalysisUsage(AnalysisUsage & AU) const83 void getAnalysisUsage(AnalysisUsage &AU) const override {
84 AliasAnalysis::getAnalysisUsage(AU);
85 AU.addRequired<AliasAnalysis>();
86 AU.setPreservesAll();
87 }
88
89 /// getAdjustedAnalysisPointer - This method is used when a pass implements
90 /// an analysis interface through multiple inheritance. If needed, it
91 /// should override this to adjust the this pointer as needed for the
92 /// specified pass info.
getAdjustedAnalysisPointer(AnalysisID PI)93 void *getAdjustedAnalysisPointer(AnalysisID PI) override {
94 if (PI == &AliasAnalysis::ID)
95 return (AliasAnalysis*)this;
96 return this;
97 }
98
99 // FIXME: We could count these too...
pointsToConstantMemory(const Location & Loc,bool OrLocal)100 bool pointsToConstantMemory(const Location &Loc, bool OrLocal) override {
101 return getAnalysis<AliasAnalysis>().pointsToConstantMemory(Loc, OrLocal);
102 }
103
104 // Forwarding functions: just delegate to a real AA implementation, counting
105 // the number of responses...
106 AliasResult alias(const Location &LocA, const Location &LocB) override;
107
108 ModRefResult getModRefInfo(ImmutableCallSite CS,
109 const Location &Loc) override;
getModRefInfo(ImmutableCallSite CS1,ImmutableCallSite CS2)110 ModRefResult getModRefInfo(ImmutableCallSite CS1,
111 ImmutableCallSite CS2) override {
112 return AliasAnalysis::getModRefInfo(CS1,CS2);
113 }
114 };
115 }
116
117 char AliasAnalysisCounter::ID = 0;
118 INITIALIZE_AG_PASS(AliasAnalysisCounter, AliasAnalysis, "count-aa",
119 "Count Alias Analysis Query Responses", false, true, false)
120
createAliasAnalysisCounterPass()121 ModulePass *llvm::createAliasAnalysisCounterPass() {
122 return new AliasAnalysisCounter();
123 }
124
125 AliasAnalysis::AliasResult
alias(const Location & LocA,const Location & LocB)126 AliasAnalysisCounter::alias(const Location &LocA, const Location &LocB) {
127 AliasResult R = getAnalysis<AliasAnalysis>().alias(LocA, LocB);
128
129 const char *AliasString = nullptr;
130 switch (R) {
131 case NoAlias: No++; AliasString = "No alias"; break;
132 case MayAlias: May++; AliasString = "May alias"; break;
133 case PartialAlias: Partial++; AliasString = "Partial alias"; break;
134 case MustAlias: Must++; AliasString = "Must alias"; break;
135 }
136
137 if (PrintAll || (PrintAllFailures && R == MayAlias)) {
138 errs() << AliasString << ":\t";
139 errs() << "[" << LocA.Size << "B] ";
140 LocA.Ptr->printAsOperand(errs(), true, M);
141 errs() << ", ";
142 errs() << "[" << LocB.Size << "B] ";
143 LocB.Ptr->printAsOperand(errs(), true, M);
144 errs() << "\n";
145 }
146
147 return R;
148 }
149
150 AliasAnalysis::ModRefResult
getModRefInfo(ImmutableCallSite CS,const Location & Loc)151 AliasAnalysisCounter::getModRefInfo(ImmutableCallSite CS,
152 const Location &Loc) {
153 ModRefResult R = getAnalysis<AliasAnalysis>().getModRefInfo(CS, Loc);
154
155 const char *MRString = nullptr;
156 switch (R) {
157 case NoModRef: NoMR++; MRString = "NoModRef"; break;
158 case Ref: JustRef++; MRString = "JustRef"; break;
159 case Mod: JustMod++; MRString = "JustMod"; break;
160 case ModRef: MR++; MRString = "ModRef"; break;
161 }
162
163 if (PrintAll || (PrintAllFailures && R == ModRef)) {
164 errs() << MRString << ": Ptr: ";
165 errs() << "[" << Loc.Size << "B] ";
166 Loc.Ptr->printAsOperand(errs(), true, M);
167 errs() << "\t<->" << *CS.getInstruction() << '\n';
168 }
169 return R;
170 }
171