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AliasDebugger.cpp
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1 //===- AliasDebugger.cpp - Simple Alias Analysis Use Checker --------------===//
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 simple pass checks alias analysis users to ensure that if they
11 // create a new value, they do not query AA without informing it of the value.
12 // It acts as a shim over any other AA pass you want.
13 //
14 // Yes keeping track of every value in the program is expensive, but this is
15 // a debugging pass.
16 //
17 //===----------------------------------------------------------------------===//
18 
19 #include "llvm/Analysis/Passes.h"
21 #include "llvm/IR/Constants.h"
22 #include "llvm/IR/DerivedTypes.h"
23 #include "llvm/IR/Instructions.h"
24 #include "llvm/IR/Module.h"
25 #include "llvm/Pass.h"
26 #include <set>
27 using namespace llvm;
28 
29 namespace {
30 
31  class AliasDebugger : public ModulePass, public AliasAnalysis {
32 
33  //What we do is simple. Keep track of every value the AA could
34  //know about, and verify that queries are one of those.
35  //A query to a value that didn't exist when the AA was created
36  //means someone forgot to update the AA when creating new values
37 
38  std::set<const Value*> Vals;
39 
40  public:
41  static char ID; // Class identification, replacement for typeinfo
42  AliasDebugger() : ModulePass(ID) {
44  }
45 
46  bool runOnModule(Module &M) {
47  InitializeAliasAnalysis(this); // set up super class
48 
50  E = M.global_end(); I != E; ++I) {
51  Vals.insert(&*I);
52  for (User::const_op_iterator OI = I->op_begin(),
53  OE = I->op_end(); OI != OE; ++OI)
54  Vals.insert(*OI);
55  }
56 
57  for(Module::iterator I = M.begin(),
58  E = M.end(); I != E; ++I){
59  Vals.insert(&*I);
60  if(!I->isDeclaration()) {
61  for (Function::arg_iterator AI = I->arg_begin(), AE = I->arg_end();
62  AI != AE; ++AI)
63  Vals.insert(&*AI);
64  for (Function::const_iterator FI = I->begin(), FE = I->end();
65  FI != FE; ++FI)
66  for (BasicBlock::const_iterator BI = FI->begin(), BE = FI->end();
67  BI != BE; ++BI) {
68  Vals.insert(&*BI);
69  for (User::const_op_iterator OI = BI->op_begin(),
70  OE = BI->op_end(); OI != OE; ++OI)
71  Vals.insert(*OI);
72  }
73  }
74 
75  }
76  return false;
77  }
78 
79  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
81  AU.setPreservesAll(); // Does not transform code
82  }
83 
84  /// getAdjustedAnalysisPointer - This method is used when a pass implements
85  /// an analysis interface through multiple inheritance. If needed, it
86  /// should override this to adjust the this pointer as needed for the
87  /// specified pass info.
88  virtual void *getAdjustedAnalysisPointer(AnalysisID PI) {
89  if (PI == &AliasAnalysis::ID)
90  return (AliasAnalysis*)this;
91  return this;
92  }
93 
94  //------------------------------------------------
95  // Implement the AliasAnalysis API
96  //
97  AliasResult alias(const Location &LocA, const Location &LocB) {
98  assert(Vals.find(LocA.Ptr) != Vals.end() &&
99  "Never seen value in AA before");
100  assert(Vals.find(LocB.Ptr) != Vals.end() &&
101  "Never seen value in AA before");
102  return AliasAnalysis::alias(LocA, LocB);
103  }
104 
105  ModRefResult getModRefInfo(ImmutableCallSite CS,
106  const Location &Loc) {
107  assert(Vals.find(Loc.Ptr) != Vals.end() && "Never seen value in AA before");
108  return AliasAnalysis::getModRefInfo(CS, Loc);
109  }
110 
111  ModRefResult getModRefInfo(ImmutableCallSite CS1,
112  ImmutableCallSite CS2) {
113  return AliasAnalysis::getModRefInfo(CS1,CS2);
114  }
115 
116  bool pointsToConstantMemory(const Location &Loc, bool OrLocal) {
117  assert(Vals.find(Loc.Ptr) != Vals.end() && "Never seen value in AA before");
118  return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
119  }
120 
121  virtual void deleteValue(Value *V) {
122  assert(Vals.find(V) != Vals.end() && "Never seen value in AA before");
124  }
125  virtual void copyValue(Value *From, Value *To) {
126  Vals.insert(To);
127  AliasAnalysis::copyValue(From, To);
128  }
129 
130  };
131 }
132 
133 char AliasDebugger::ID = 0;
134 INITIALIZE_AG_PASS(AliasDebugger, AliasAnalysis, "debug-aa",
135  "AA use debugger", false, true, false)
136 
137 Pass *llvm::createAliasDebugger() { return new AliasDebugger(); }
138 
virtual bool pointsToConstantMemory(const Location &Loc, bool OrLocal=false)
static PassRegistry * getPassRegistry()
ModRefResult getModRefInfo(const Instruction *I, const Location &Loc)
The main container class for the LLVM Intermediate Representation.
Definition: Module.h:112
Definition: Use.h:60
INITIALIZE_AG_PASS(AliasDebugger, AliasAnalysis,"debug-aa","AA use debugger", false, true, false) Pass *llvm
ID
LLVM Calling Convention Representation.
Definition: CallingConv.h:26
virtual void copyValue(Value *From, Value *To)
global_iterator global_begin()
Definition: Module.h:521
void initializeAliasDebuggerPass(PassRegistry &)
virtual AliasResult alias(const Location &LocA, const Location &LocB)
virtual void deleteValue(Value *V)
global_iterator global_end()
Definition: Module.h:523
iterator end()
Definition: Module.h:533
ImmutableCallSite - establish a view to a call site for examination.
Definition: CallSite.h:318
#define I(x, y, z)
Definition: MD5.cpp:54
iterator begin()
Definition: Module.h:531
const void * AnalysisID
Definition: Pass.h:47
Pass * createAliasDebugger()
LLVM Value Representation.
Definition: Value.h:66
virtual void getAnalysisUsage(AnalysisUsage &AU) const