1 //===- AliasDebugger.cpp - Simple Alias Analysis Use Checker --------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Andrew Lenharth and is distributed under
6 // the University of Illinois Open Source 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"
31 class AliasDebugger : public ModulePass, public AliasAnalysis {
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
38 std::set<const Value*> Vals;
41 bool runOnModule(Module &M) {
42 InitializeAliasAnalysis(this); // set up super class
44 for(Module::global_iterator I = M.global_begin(),
45 E = M.global_end(); I != E; ++I)
48 for(Module::iterator I = M.begin(),
49 E = M.end(); I != E; ++I){
51 if(!I->isExternal()) {
52 for (Function::arg_iterator AI = I->arg_begin(), AE = I->arg_end();
55 for (Function::const_iterator FI = I->begin(), FE = I->end();
57 for (BasicBlock::const_iterator BI = FI->begin(), BE = FI->end();
66 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
67 AliasAnalysis::getAnalysisUsage(AU);
68 AU.setPreservesAll(); // Does not transform code
71 //------------------------------------------------
72 // Implement the AliasAnalysis API
74 AliasResult alias(const Value *V1, unsigned V1Size,
75 const Value *V2, unsigned V2Size) {
76 assert(Vals.find(V1) != Vals.end() && "Never seen value in AA before");
77 assert(Vals.find(V2) != Vals.end() && "Never seen value in AA before");
78 return AliasAnalysis::alias(V1, V1Size, V2, V2Size);
81 ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size) {
82 assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
83 return AliasAnalysis::getModRefInfo(CS, P, Size);
86 ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) {
87 return AliasAnalysis::getModRefInfo(CS1,CS2);
90 void getMustAliases(Value *P, std::vector<Value*> &RetVals) {
91 assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
92 return AliasAnalysis::getMustAliases(P, RetVals);
95 bool pointsToConstantMemory(const Value *P) {
96 assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
97 return AliasAnalysis::pointsToConstantMemory(P);
100 /// getModRefBehavior - Return the behavior of the specified function if
101 /// called from the specified call site. The call site may be null in which
102 /// case the most generic behavior of this function should be returned.
103 virtual ModRefBehavior getModRefBehavior(Function *F, CallSite CS,
104 std::vector<PointerAccessInfo> *Info) {
105 assert(Vals.find(F) != Vals.end() && "Never seen value in AA before");
106 return AliasAnalysis::getModRefBehavior(F, CS, Info);
109 virtual void deleteValue(Value *V) {
110 assert(Vals.find(V) != Vals.end() && "Never seen value in AA before");
111 AliasAnalysis::deleteValue(V);
113 virtual void copyValue(Value *From, Value *To) {
115 AliasAnalysis::copyValue(From, To);
120 RegisterPass<AliasDebugger> X("debug-aa", "AA use debugger");
121 RegisterAnalysisGroup<AliasAnalysis> Y(X);
124 Pass *llvm::createAliasDebugger() { return new AliasDebugger(); }