1132718Skan//===- AliasDebugger.cpp - Simple Alias Analysis Use Checker --------------===// 2169689Skan// 3132718Skan// The LLVM Compiler Infrastructure 4132718Skan// 5132718Skan// This file is distributed under the University of Illinois Open Source 6132718Skan// License. See LICENSE.TXT for details. 7132718Skan// 8132718Skan//===----------------------------------------------------------------------===// 9132718Skan// 10132718Skan// This simple pass checks alias analysis users to ensure that if they 11132718Skan// create a new value, they do not query AA without informing it of the value. 12132718Skan// It acts as a shim over any other AA pass you want. 13132718Skan// 14132718Skan// Yes keeping track of every value in the program is expensive, but this is 15132718Skan// a debugging pass. 16132718Skan// 17132718Skan//===----------------------------------------------------------------------===// 18169689Skan 19169689Skan#include "llvm/Analysis/Passes.h" 20132718Skan#include "llvm/Analysis/AliasAnalysis.h" 21132718Skan#include "llvm/IR/Constants.h" 22132718Skan#include "llvm/IR/DerivedTypes.h" 23132718Skan#include "llvm/IR/Instructions.h" 24132718Skan#include "llvm/IR/Module.h" 25132718Skan#include "llvm/Pass.h" 26132718Skan#include <set> 27132718Skanusing namespace llvm; 28132718Skan 29132718Skannamespace { 30132718Skan 31132718Skan class AliasDebugger : public ModulePass, public AliasAnalysis { 32132718Skan 33132718Skan //What we do is simple. Keep track of every value the AA could 34132718Skan //know about, and verify that queries are one of those. 35132718Skan //A query to a value that didn't exist when the AA was created 36132718Skan //means someone forgot to update the AA when creating new values 37132718Skan 38132718Skan std::set<const Value*> Vals; 39132718Skan 40132718Skan public: 41132718Skan static char ID; // Class identification, replacement for typeinfo 42132718Skan AliasDebugger() : ModulePass(ID) { 43132718Skan initializeAliasDebuggerPass(*PassRegistry::getPassRegistry()); 44132718Skan } 45132718Skan 46132718Skan bool runOnModule(Module &M) { 47132718Skan InitializeAliasAnalysis(this); // set up super class 48132718Skan 49132718Skan for(Module::global_iterator I = M.global_begin(), 50132718Skan E = M.global_end(); I != E; ++I) { 51132718Skan Vals.insert(&*I); 52132718Skan for (User::const_op_iterator OI = I->op_begin(), 53132718Skan OE = I->op_end(); OI != OE; ++OI) 54132718Skan Vals.insert(*OI); 55132718Skan } 56132718Skan 57132718Skan for(Module::iterator I = M.begin(), 58132718Skan E = M.end(); I != E; ++I){ 59132718Skan Vals.insert(&*I); 60132718Skan if(!I->isDeclaration()) { 61132718Skan for (Function::arg_iterator AI = I->arg_begin(), AE = I->arg_end(); 62132718Skan AI != AE; ++AI) 63132718Skan Vals.insert(&*AI); 64169689Skan for (Function::const_iterator FI = I->begin(), FE = I->end(); 65169689Skan FI != FE; ++FI) 66169689Skan for (BasicBlock::const_iterator BI = FI->begin(), BE = FI->end(); 67169689Skan BI != BE; ++BI) { 68169689Skan Vals.insert(&*BI); 69132718Skan for (User::const_op_iterator OI = BI->op_begin(), 70169689Skan OE = BI->op_end(); OI != OE; ++OI) 71132718Skan Vals.insert(*OI); 72132718Skan } 73132718Skan } 74132718Skan 75132718Skan } 76132718Skan return false; 77132718Skan } 78132718Skan 79132718Skan virtual void getAnalysisUsage(AnalysisUsage &AU) const { 80132718Skan AliasAnalysis::getAnalysisUsage(AU); 81132718Skan AU.setPreservesAll(); // Does not transform code 82132718Skan } 83132718Skan 84132718Skan /// getAdjustedAnalysisPointer - This method is used when a pass implements 85132718Skan /// an analysis interface through multiple inheritance. If needed, it 86132718Skan /// should override this to adjust the this pointer as needed for the 87132718Skan /// specified pass info. 88169689Skan virtual void *getAdjustedAnalysisPointer(AnalysisID PI) { 89169689Skan if (PI == &AliasAnalysis::ID) 90132718Skan return (AliasAnalysis*)this; 91169689Skan return this; 92169689Skan } 93132718Skan 94169689Skan //------------------------------------------------ 95132718Skan // Implement the AliasAnalysis API 96132718Skan // 97132718Skan AliasResult alias(const Location &LocA, const Location &LocB) { 98261188Spfg assert(Vals.find(LocA.Ptr) != Vals.end() && 99261188Spfg "Never seen value in AA before"); 100261188Spfg assert(Vals.find(LocB.Ptr) != Vals.end() && 101261188Spfg "Never seen value in AA before"); 102261188Spfg return AliasAnalysis::alias(LocA, LocB); 103261188Spfg } 104261188Spfg 105261188Spfg ModRefResult getModRefInfo(ImmutableCallSite CS, 106261188Spfg const Location &Loc) { 107261188Spfg assert(Vals.find(Loc.Ptr) != Vals.end() && "Never seen value in AA before"); 108261188Spfg return AliasAnalysis::getModRefInfo(CS, Loc); 109261188Spfg } 110169689Skan 111169689Skan ModRefResult getModRefInfo(ImmutableCallSite CS1, 112169689Skan ImmutableCallSite CS2) { 113169689Skan return AliasAnalysis::getModRefInfo(CS1,CS2); 114169689Skan } 115169689Skan 116169689Skan bool pointsToConstantMemory(const Location &Loc, bool OrLocal) { 117169689Skan assert(Vals.find(Loc.Ptr) != Vals.end() && "Never seen value in AA before"); 118169689Skan return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal); 119169689Skan } 120169689Skan 121169689Skan virtual void deleteValue(Value *V) { 122169689Skan assert(Vals.find(V) != Vals.end() && "Never seen value in AA before"); 123169689Skan AliasAnalysis::deleteValue(V); 124169689Skan } 125169689Skan virtual void copyValue(Value *From, Value *To) { 126169689Skan Vals.insert(To); 127169689Skan AliasAnalysis::copyValue(From, To); 128169689Skan } 129169689Skan 130169689Skan }; 131169689Skan} 132169689Skan 133169689Skanchar AliasDebugger::ID = 0; 134169689SkanINITIALIZE_AG_PASS(AliasDebugger, AliasAnalysis, "debug-aa", 135169689Skan "AA use debugger", false, true, false) 136132718Skan 137169689SkanPass *llvm::createAliasDebugger() { return new AliasDebugger(); } 138132718Skan 139132718Skan