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AliasAnalysisCounter.cpp
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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"
17 #include "llvm/Assembly/Writer.h"
18 #include "llvm/Pass.h"
20 #include "llvm/Support/Debug.h"
23 using namespace llvm;
24 
25 static cl::opt<bool>
26 PrintAll("count-aa-print-all-queries", cl::ReallyHidden, cl::init(true));
27 static cl::opt<bool>
28 PrintAllFailures("count-aa-print-all-failed-queries", cl::ReallyHidden);
29 
30 namespace {
31  class AliasAnalysisCounter : public ModulePass, public AliasAnalysis {
32  unsigned No, May, Partial, Must;
33  unsigned NoMR, JustRef, JustMod, MR;
34  Module *M;
35  public:
36  static char ID; // Class identification, replacement for typeinfo
37  AliasAnalysisCounter() : ModulePass(ID) {
39  No = May = Partial = Must = 0;
40  NoMR = JustRef = JustMod = MR = 0;
41  }
42 
43  void printLine(const char *Desc, unsigned Val, unsigned Sum) {
44  errs() << " " << Val << " " << Desc << " responses ("
45  << Val*100/Sum << "%)\n";
46  }
47  ~AliasAnalysisCounter() {
48  unsigned AASum = No+May+Partial+Must;
49  unsigned MRSum = NoMR+JustRef+JustMod+MR;
50  if (AASum + MRSum) { // Print a report if any counted queries occurred...
51  errs() << "\n===== Alias Analysis Counter Report =====\n"
52  << " Analysis counted:\n"
53  << " " << AASum << " Total Alias Queries Performed\n";
54  if (AASum) {
55  printLine("no alias", No, AASum);
56  printLine("may alias", May, AASum);
57  printLine("partial alias", Partial, AASum);
58  printLine("must alias", Must, AASum);
59  errs() << " Alias Analysis Counter Summary: " << No*100/AASum << "%/"
60  << May*100/AASum << "%/"
61  << Partial*100/AASum << "%/"
62  << Must*100/AASum<<"%\n\n";
63  }
64 
65  errs() << " " << MRSum << " Total Mod/Ref Queries Performed\n";
66  if (MRSum) {
67  printLine("no mod/ref", NoMR, MRSum);
68  printLine("ref", JustRef, MRSum);
69  printLine("mod", JustMod, MRSum);
70  printLine("mod/ref", MR, MRSum);
71  errs() << " Mod/Ref Analysis Counter Summary: " <<NoMR*100/MRSum
72  << "%/" << JustRef*100/MRSum << "%/" << JustMod*100/MRSum
73  << "%/" << MR*100/MRSum <<"%\n\n";
74  }
75  }
76  }
77 
78  bool runOnModule(Module &M) {
79  this->M = &M;
80  InitializeAliasAnalysis(this);
81  return false;
82  }
83 
84  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
87  AU.setPreservesAll();
88  }
89 
90  /// getAdjustedAnalysisPointer - This method is used when a pass implements
91  /// an analysis interface through multiple inheritance. If needed, it
92  /// should override this to adjust the this pointer as needed for the
93  /// specified pass info.
94  virtual void *getAdjustedAnalysisPointer(AnalysisID PI) {
95  if (PI == &AliasAnalysis::ID)
96  return (AliasAnalysis*)this;
97  return this;
98  }
99 
100  // FIXME: We could count these too...
101  bool pointsToConstantMemory(const Location &Loc, bool OrLocal) {
102  return getAnalysis<AliasAnalysis>().pointsToConstantMemory(Loc, OrLocal);
103  }
104 
105  // Forwarding functions: just delegate to a real AA implementation, counting
106  // the number of responses...
107  AliasResult alias(const Location &LocA, const Location &LocB);
108 
109  ModRefResult getModRefInfo(ImmutableCallSite CS,
110  const Location &Loc);
111  ModRefResult getModRefInfo(ImmutableCallSite CS1,
112  ImmutableCallSite CS2) {
113  return AliasAnalysis::getModRefInfo(CS1,CS2);
114  }
115  };
116 }
117 
118 char AliasAnalysisCounter::ID = 0;
119 INITIALIZE_AG_PASS(AliasAnalysisCounter, AliasAnalysis, "count-aa",
120  "Count Alias Analysis Query Responses", false, true, false)
121 
123  return new AliasAnalysisCounter();
124 }
125 
127 AliasAnalysisCounter::alias(const Location &LocA, const Location &LocB) {
128  AliasResult R = getAnalysis<AliasAnalysis>().alias(LocA, LocB);
129 
130  const char *AliasString = 0;
131  switch (R) {
132  case NoAlias: No++; AliasString = "No alias"; break;
133  case MayAlias: May++; AliasString = "May alias"; break;
134  case PartialAlias: Partial++; AliasString = "Partial alias"; break;
135  case MustAlias: Must++; AliasString = "Must alias"; break;
136  }
137 
138  if (PrintAll || (PrintAllFailures && R == MayAlias)) {
139  errs() << AliasString << ":\t";
140  errs() << "[" << LocA.Size << "B] ";
141  WriteAsOperand(errs(), LocA.Ptr, true, M);
142  errs() << ", ";
143  errs() << "[" << LocB.Size << "B] ";
144  WriteAsOperand(errs(), LocB.Ptr, true, M);
145  errs() << "\n";
146  }
147 
148  return R;
149 }
150 
152 AliasAnalysisCounter::getModRefInfo(ImmutableCallSite CS,
153  const Location &Loc) {
154  ModRefResult R = getAnalysis<AliasAnalysis>().getModRefInfo(CS, Loc);
155 
156  const char *MRString = 0;
157  switch (R) {
158  case NoModRef: NoMR++; MRString = "NoModRef"; break;
159  case Ref: JustRef++; MRString = "JustRef"; break;
160  case Mod: JustMod++; MRString = "JustMod"; break;
161  case ModRef: MR++; MRString = "ModRef"; break;
162  }
163 
164  if (PrintAll || (PrintAllFailures && R == ModRef)) {
165  errs() << MRString << ": Ptr: ";
166  errs() << "[" << Loc.Size << "B] ";
167  WriteAsOperand(errs(), Loc.Ptr, true, M);
168  errs() << "\t<->" << *CS.getInstruction() << '\n';
169  }
170  return R;
171 }
raw_ostream & errs()
static PassRegistry * getPassRegistry()
ModRefResult getModRefInfo(const Instruction *I, const Location &Loc)
The main container class for the LLVM Intermediate Representation.
Definition: Module.h:112
void WriteAsOperand(raw_ostream &, const Value *, bool PrintTy=true, const Module *Context=0)
Definition: AsmWriter.cpp:1179
AnalysisUsage & addRequired()
INITIALIZE_AG_PASS(AliasAnalysisCounter, AliasAnalysis,"count-aa","Count Alias Analysis Query Responses", false, true, false) ModulePass *llvm
ModulePass * createAliasAnalysisCounterPass()
ID
LLVM Calling Convention Representation.
Definition: CallingConv.h:26
void initializeAliasAnalysisCounterPass(PassRegistry &)
static cl::opt< bool > PrintAllFailures("count-aa-print-all-failed-queries", cl::ReallyHidden)
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:314
InstrTy * getInstruction() const
Definition: CallSite.h:79
static cl::opt< bool > PrintAll("count-aa-print-all-queries", cl::ReallyHidden, cl::init(true))
static void printLine(raw_ostream &OS, const Twine &Prefix, char Fill, StringRef Suffix)
ImmutableCallSite - establish a view to a call site for examination.
Definition: CallSite.h:318
const void * AnalysisID
Definition: Pass.h:47
virtual void getAnalysisUsage(AnalysisUsage &AU) const