1 //===- AliasDebugger.cpp - Simple Alias Analysis Use Checker --------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
14 // Yes keeping track of every value in the program is expensive, but this is
17 //===----------------------------------------------------------------------===//
19 #include "llvm/Analysis/Passes.h"
20 #include "llvm/Module.h"
21 #include "llvm/Pass.h"
22 #include "llvm/Instructions.h"
23 #include "llvm/Constants.h"
24 #include "llvm/DerivedTypes.h"
25 #include "llvm/Analysis/AliasAnalysis.h"
26 #include "llvm/Support/Compiler.h"
32 class AliasDebugger : public ModulePass, public AliasAnalysis {
34 //What we do is simple. Keep track of every value the AA could
35 //know about, and verify that queries are one of those.
36 //A query to a value that didn't exist when the AA was created
37 //means someone forgot to update the AA when creating new values
39 std::set<const Value*> Vals;
42 static char ID; // Class identification, replacement for typeinfo
43 AliasDebugger() : ModulePass(&ID) {}
45 bool runOnModule(Module &M) {
46 InitializeAliasAnalysis(this); // set up super class
48 for(Module::global_iterator I = M.global_begin(),
49 E = M.global_end(); I != E; ++I)
52 for(Module::iterator I = M.begin(),
53 E = M.end(); I != E; ++I){
55 if(!I->isDeclaration()) {
56 for (Function::arg_iterator AI = I->arg_begin(), AE = I->arg_end();
59 for (Function::const_iterator FI = I->begin(), FE = I->end();
61 for (BasicBlock::const_iterator BI = FI->begin(), BE = FI->end();
70 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
71 AliasAnalysis::getAnalysisUsage(AU);
72 AU.setPreservesAll(); // Does not transform code
75 //------------------------------------------------
76 // Implement the AliasAnalysis API
78 AliasResult alias(const Value *V1, unsigned V1Size,
79 const Value *V2, unsigned V2Size) {
80 assert(Vals.find(V1) != Vals.end() && "Never seen value in AA before");
81 assert(Vals.find(V2) != Vals.end() && "Never seen value in AA before");
82 return AliasAnalysis::alias(V1, V1Size, V2, V2Size);
85 ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size) {
86 assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
87 return AliasAnalysis::getModRefInfo(CS, P, Size);
90 ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) {
91 return AliasAnalysis::getModRefInfo(CS1,CS2);
94 void getMustAliases(Value *P, std::vector<Value*> &RetVals) {
95 assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
96 return AliasAnalysis::getMustAliases(P, RetVals);
99 bool pointsToConstantMemory(const Value *P) {
100 assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
101 return AliasAnalysis::pointsToConstantMemory(P);
104 virtual void deleteValue(Value *V) {
105 assert(Vals.find(V) != Vals.end() && "Never seen value in AA before");
106 AliasAnalysis::deleteValue(V);
108 virtual void copyValue(Value *From, Value *To) {
110 AliasAnalysis::copyValue(From, To);
116 char AliasDebugger::ID = 0;
117 static RegisterPass<AliasDebugger>
118 X("debug-aa", "AA use debugger", false, true);
119 static RegisterAnalysisGroup<AliasAnalysis> Y(X);
121 Pass *llvm::createAliasDebugger() { return new AliasDebugger(); }