| //===- AliasSetTracker.cpp - Alias Sets Tracker implementation-------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by the LLVM research group and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the AliasSetTracker and AliasSet classes. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Analysis/AliasSetTracker.h" |
| #include "llvm/Analysis/AliasAnalysis.h" |
| #include "llvm/Instructions.h" |
| #include "llvm/Pass.h" |
| #include "llvm/Type.h" |
| #include "llvm/Target/TargetData.h" |
| #include "llvm/Assembly/Writer.h" |
| #include "llvm/Support/InstIterator.h" |
| #include <iostream> |
| using namespace llvm; |
| |
| /// mergeSetIn - Merge the specified alias set into this alias set. |
| /// |
| void AliasSet::mergeSetIn(AliasSet &AS, AliasSetTracker &AST) { |
| assert(!AS.Forward && "Alias set is already forwarding!"); |
| assert(!Forward && "This set is a forwarding set!!"); |
| |
| // Update the alias and access types of this set... |
| AccessTy |= AS.AccessTy; |
| AliasTy |= AS.AliasTy; |
| |
| if (AliasTy == MustAlias) { |
| // Check that these two merged sets really are must aliases. Since both |
| // used to be must-alias sets, we can just check any pointer from each set |
| // for aliasing. |
| AliasAnalysis &AA = AST.getAliasAnalysis(); |
| HashNodePair *L = getSomePointer(); |
| HashNodePair *R = AS.getSomePointer(); |
| |
| // If the pointers are not a must-alias pair, this set becomes a may alias. |
| if (AA.alias(L->first, L->second.getSize(), R->first, R->second.getSize()) |
| != AliasAnalysis::MustAlias) |
| AliasTy = MayAlias; |
| } |
| |
| if (CallSites.empty()) { // Merge call sites... |
| if (!AS.CallSites.empty()) |
| std::swap(CallSites, AS.CallSites); |
| } else if (!AS.CallSites.empty()) { |
| CallSites.insert(CallSites.end(), AS.CallSites.begin(), AS.CallSites.end()); |
| AS.CallSites.clear(); |
| } |
| |
| AS.Forward = this; // Forward across AS now... |
| addRef(); // AS is now pointing to us... |
| |
| // Merge the list of constituent pointers... |
| if (AS.PtrList) { |
| *PtrListEnd = AS.PtrList; |
| AS.PtrList->second.setPrevInList(PtrListEnd); |
| PtrListEnd = AS.PtrListEnd; |
| |
| AS.PtrList = 0; |
| AS.PtrListEnd = &AS.PtrList; |
| assert(*AS.PtrListEnd == 0 && "End of list is not null?"); |
| } |
| } |
| |
| void AliasSetTracker::removeAliasSet(AliasSet *AS) { |
| if (AliasSet *Fwd = AS->Forward) { |
| Fwd->dropRef(*this); |
| AS->Forward = 0; |
| } |
| AliasSets.erase(AS); |
| } |
| |
| void AliasSet::removeFromTracker(AliasSetTracker &AST) { |
| assert(RefCount == 0 && "Cannot remove non-dead alias set from tracker!"); |
| AST.removeAliasSet(this); |
| } |
| |
| void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry, |
| unsigned Size, bool KnownMustAlias) { |
| assert(!Entry.second.hasAliasSet() && "Entry already in set!"); |
| |
| // Check to see if we have to downgrade to _may_ alias. |
| if (isMustAlias() && !KnownMustAlias) |
| if (HashNodePair *P = getSomePointer()) { |
| AliasAnalysis &AA = AST.getAliasAnalysis(); |
| AliasAnalysis::AliasResult Result = |
| AA.alias(P->first, P->second.getSize(), Entry.first, Size); |
| if (Result == AliasAnalysis::MayAlias) |
| AliasTy = MayAlias; |
| else // First entry of must alias must have maximum size! |
| P->second.updateSize(Size); |
| assert(Result != AliasAnalysis::NoAlias && "Cannot be part of must set!"); |
| } |
| |
| Entry.second.setAliasSet(this); |
| Entry.second.updateSize(Size); |
| |
| // Add it to the end of the list... |
| assert(*PtrListEnd == 0 && "End of list is not null?"); |
| *PtrListEnd = &Entry; |
| PtrListEnd = Entry.second.setPrevInList(PtrListEnd); |
| assert(*PtrListEnd == 0 && "End of list is not null?"); |
| addRef(); // Entry points to alias set... |
| } |
| |
| void AliasSet::addCallSite(CallSite CS, AliasAnalysis &AA) { |
| CallSites.push_back(CS); |
| |
| if (Function *F = CS.getCalledFunction()) { |
| AliasAnalysis::ModRefBehavior Behavior = AA.getModRefBehavior(F, CS); |
| if (Behavior == AliasAnalysis::DoesNotAccessMemory) |
| return; |
| else if (Behavior == AliasAnalysis::OnlyReadsMemory) { |
| AliasTy = MayAlias; |
| AccessTy |= Refs; |
| return; |
| } |
| } |
| |
| // FIXME: This should use mod/ref information to make this not suck so bad |
| AliasTy = MayAlias; |
| AccessTy = ModRef; |
| } |
| |
| /// aliasesPointer - Return true if the specified pointer "may" (or must) |
| /// alias one of the members in the set. |
| /// |
| bool AliasSet::aliasesPointer(const Value *Ptr, unsigned Size, |
| AliasAnalysis &AA) const { |
| if (AliasTy == MustAlias) { |
| assert(CallSites.empty() && "Illegal must alias set!"); |
| |
| // If this is a set of MustAliases, only check to see if the pointer aliases |
| // SOME value in the set... |
| HashNodePair *SomePtr = getSomePointer(); |
| assert(SomePtr && "Empty must-alias set??"); |
| return AA.alias(SomePtr->first, SomePtr->second.getSize(), Ptr, Size); |
| } |
| |
| // If this is a may-alias set, we have to check all of the pointers in the set |
| // to be sure it doesn't alias the set... |
| for (iterator I = begin(), E = end(); I != E; ++I) |
| if (AA.alias(Ptr, Size, I.getPointer(), I.getSize())) |
| return true; |
| |
| // Check the call sites list and invoke list... |
| if (!CallSites.empty()) { |
| if (AA.hasNoModRefInfoForCalls()) |
| return true; |
| |
| for (unsigned i = 0, e = CallSites.size(); i != e; ++i) |
| if (AA.getModRefInfo(CallSites[i], const_cast<Value*>(Ptr), Size) |
| != AliasAnalysis::NoModRef) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const { |
| if (Function *F = CS.getCalledFunction()) |
| if (AA.doesNotAccessMemory(F)) |
| return false; |
| |
| if (AA.hasNoModRefInfoForCalls()) |
| return true; |
| |
| for (unsigned i = 0, e = CallSites.size(); i != e; ++i) |
| if (AA.getModRefInfo(CallSites[i], CS) != AliasAnalysis::NoModRef || |
| AA.getModRefInfo(CS, CallSites[i]) != AliasAnalysis::NoModRef) |
| return true; |
| |
| for (iterator I = begin(), E = end(); I != E; ++I) |
| if (AA.getModRefInfo(CS, I.getPointer(), I.getSize()) != |
| AliasAnalysis::NoModRef) |
| return true; |
| |
| return false; |
| } |
| |
| |
| /// findAliasSetForPointer - Given a pointer, find the one alias set to put the |
| /// instruction referring to the pointer into. If there are multiple alias sets |
| /// that may alias the pointer, merge them together and return the unified set. |
| /// |
| AliasSet *AliasSetTracker::findAliasSetForPointer(const Value *Ptr, |
| unsigned Size) { |
| AliasSet *FoundSet = 0; |
| for (iterator I = begin(), E = end(); I != E; ++I) |
| if (!I->Forward && I->aliasesPointer(Ptr, Size, AA)) { |
| if (FoundSet == 0) { // If this is the first alias set ptr can go into. |
| FoundSet = I; // Remember it. |
| } else { // Otherwise, we must merge the sets. |
| FoundSet->mergeSetIn(*I, *this); // Merge in contents. |
| } |
| } |
| |
| return FoundSet; |
| } |
| |
| /// containsPointer - Return true if the specified location is represented by |
| /// this alias set, false otherwise. This does not modify the AST object or |
| /// alias sets. |
| bool AliasSetTracker::containsPointer(Value *Ptr, unsigned Size) const { |
| for (const_iterator I = begin(), E = end(); I != E; ++I) |
| if (!I->Forward && I->aliasesPointer(Ptr, Size, AA)) |
| return true; |
| return false; |
| } |
| |
| |
| |
| AliasSet *AliasSetTracker::findAliasSetForCallSite(CallSite CS) { |
| AliasSet *FoundSet = 0; |
| for (iterator I = begin(), E = end(); I != E; ++I) |
| if (!I->Forward && I->aliasesCallSite(CS, AA)) { |
| if (FoundSet == 0) { // If this is the first alias set ptr can go into. |
| FoundSet = I; // Remember it. |
| } else if (!I->Forward) { // Otherwise, we must merge the sets. |
| FoundSet->mergeSetIn(*I, *this); // Merge in contents. |
| } |
| } |
| |
| return FoundSet; |
| } |
| |
| |
| |
| |
| /// getAliasSetForPointer - Return the alias set that the specified pointer |
| /// lives in... |
| AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, unsigned Size, |
| bool *New) { |
| AliasSet::HashNodePair &Entry = getEntryFor(Pointer); |
| |
| // Check to see if the pointer is already known... |
| if (Entry.second.hasAliasSet()) { |
| Entry.second.updateSize(Size); |
| // Return the set! |
| return *Entry.second.getAliasSet(*this)->getForwardedTarget(*this); |
| } else if (AliasSet *AS = findAliasSetForPointer(Pointer, Size)) { |
| // Add it to the alias set it aliases... |
| AS->addPointer(*this, Entry, Size); |
| return *AS; |
| } else { |
| if (New) *New = true; |
| // Otherwise create a new alias set to hold the loaded pointer... |
| AliasSets.push_back(new AliasSet()); |
| AliasSets.back().addPointer(*this, Entry, Size); |
| return AliasSets.back(); |
| } |
| } |
| |
| bool AliasSetTracker::add(Value *Ptr, unsigned Size) { |
| bool NewPtr; |
| addPointer(Ptr, Size, AliasSet::NoModRef, NewPtr); |
| return NewPtr; |
| } |
| |
| |
| bool AliasSetTracker::add(LoadInst *LI) { |
| bool NewPtr; |
| AliasSet &AS = addPointer(LI->getOperand(0), |
| AA.getTargetData().getTypeSize(LI->getType()), |
| AliasSet::Refs, NewPtr); |
| if (LI->isVolatile()) AS.setVolatile(); |
| return NewPtr; |
| } |
| |
| bool AliasSetTracker::add(StoreInst *SI) { |
| bool NewPtr; |
| Value *Val = SI->getOperand(0); |
| AliasSet &AS = addPointer(SI->getOperand(1), |
| AA.getTargetData().getTypeSize(Val->getType()), |
| AliasSet::Mods, NewPtr); |
| if (SI->isVolatile()) AS.setVolatile(); |
| return NewPtr; |
| } |
| |
| bool AliasSetTracker::add(FreeInst *FI) { |
| bool NewPtr; |
| AliasSet &AS = addPointer(FI->getOperand(0), ~0, |
| AliasSet::Mods, NewPtr); |
| |
| // Free operations are volatile ops (cannot be moved). |
| AS.setVolatile(); |
| return NewPtr; |
| } |
| |
| |
| bool AliasSetTracker::add(CallSite CS) { |
| if (Function *F = CS.getCalledFunction()) |
| if (AA.doesNotAccessMemory(F)) |
| return true; // doesn't alias anything |
| |
| AliasSet *AS = findAliasSetForCallSite(CS); |
| if (!AS) { |
| AliasSets.push_back(new AliasSet()); |
| AS = &AliasSets.back(); |
| AS->addCallSite(CS, AA); |
| return true; |
| } else { |
| AS->addCallSite(CS, AA); |
| return false; |
| } |
| } |
| |
| bool AliasSetTracker::add(Instruction *I) { |
| // Dispatch to one of the other add methods... |
| if (LoadInst *LI = dyn_cast<LoadInst>(I)) |
| return add(LI); |
| else if (StoreInst *SI = dyn_cast<StoreInst>(I)) |
| return add(SI); |
| else if (CallInst *CI = dyn_cast<CallInst>(I)) |
| return add(CI); |
| else if (InvokeInst *II = dyn_cast<InvokeInst>(I)) |
| return add(II); |
| else if (FreeInst *FI = dyn_cast<FreeInst>(I)) |
| return add(FI); |
| return true; |
| } |
| |
| void AliasSetTracker::add(BasicBlock &BB) { |
| for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I) |
| add(I); |
| } |
| |
| void AliasSetTracker::add(const AliasSetTracker &AST) { |
| assert(&AA == &AST.AA && |
| "Merging AliasSetTracker objects with different Alias Analyses!"); |
| |
| // Loop over all of the alias sets in AST, adding the pointers contained |
| // therein into the current alias sets. This can cause alias sets to be |
| // merged together in the current AST. |
| for (const_iterator I = AST.begin(), E = AST.end(); I != E; ++I) |
| if (!I->Forward) { // Ignore forwarding alias sets |
| AliasSet &AS = const_cast<AliasSet&>(*I); |
| |
| // If there are any call sites in the alias set, add them to this AST. |
| for (unsigned i = 0, e = AS.CallSites.size(); i != e; ++i) |
| add(AS.CallSites[i]); |
| |
| // Loop over all of the pointers in this alias set... |
| AliasSet::iterator I = AS.begin(), E = AS.end(); |
| bool X; |
| for (; I != E; ++I) |
| addPointer(I.getPointer(), I.getSize(), |
| (AliasSet::AccessType)AS.AccessTy, X); |
| } |
| } |
| |
| /// remove - Remove the specified (potentially non-empty) alias set from the |
| /// tracker. |
| void AliasSetTracker::remove(AliasSet &AS) { |
| bool SetDead; |
| do { |
| AliasSet::iterator I = AS.begin(); |
| Value *Ptr = I.getPointer(); ++I; |
| |
| // deleteValue will delete the set automatically when the last pointer |
| // reference is destroyed. "Predict" when this will happen. |
| SetDead = I == AS.end(); |
| deleteValue(Ptr); // Delete all of the pointers from the set |
| } while (!SetDead); |
| } |
| |
| bool AliasSetTracker::remove(Value *Ptr, unsigned Size) { |
| AliasSet *AS = findAliasSetForPointer(Ptr, Size); |
| if (!AS) return false; |
| remove(*AS); |
| return true; |
| } |
| |
| bool AliasSetTracker::remove(LoadInst *LI) { |
| unsigned Size = AA.getTargetData().getTypeSize(LI->getType()); |
| AliasSet *AS = findAliasSetForPointer(LI->getOperand(0), Size); |
| if (!AS) return false; |
| remove(*AS); |
| return true; |
| } |
| |
| bool AliasSetTracker::remove(StoreInst *SI) { |
| unsigned Size = AA.getTargetData().getTypeSize(SI->getOperand(0)->getType()); |
| AliasSet *AS = findAliasSetForPointer(SI->getOperand(1), Size); |
| if (!AS) return false; |
| remove(*AS); |
| return true; |
| } |
| |
| bool AliasSetTracker::remove(FreeInst *FI) { |
| AliasSet *AS = findAliasSetForPointer(FI->getOperand(0), ~0); |
| if (!AS) return false; |
| remove(*AS); |
| return true; |
| } |
| |
| bool AliasSetTracker::remove(CallSite CS) { |
| if (Function *F = CS.getCalledFunction()) |
| if (AA.doesNotAccessMemory(F)) |
| return false; // doesn't alias anything |
| |
| AliasSet *AS = findAliasSetForCallSite(CS); |
| if (!AS) return false; |
| remove(*AS); |
| return true; |
| } |
| |
| bool AliasSetTracker::remove(Instruction *I) { |
| // Dispatch to one of the other remove methods... |
| if (LoadInst *LI = dyn_cast<LoadInst>(I)) |
| return remove(LI); |
| else if (StoreInst *SI = dyn_cast<StoreInst>(I)) |
| return remove(SI); |
| else if (CallInst *CI = dyn_cast<CallInst>(I)) |
| return remove(CI); |
| else if (FreeInst *FI = dyn_cast<FreeInst>(I)) |
| return remove(FI); |
| return true; |
| } |
| |
| |
| // deleteValue method - This method is used to remove a pointer value from the |
| // AliasSetTracker entirely. It should be used when an instruction is deleted |
| // from the program to update the AST. If you don't use this, you would have |
| // dangling pointers to deleted instructions. |
| // |
| void AliasSetTracker::deleteValue(Value *PtrVal) { |
| // Notify the alias analysis implementation that this value is gone. |
| AA.deleteValue(PtrVal); |
| |
| // First, look up the PointerRec for this pointer. |
| hash_map<Value*, AliasSet::PointerRec>::iterator I = PointerMap.find(PtrVal); |
| if (I == PointerMap.end()) return; // Noop |
| |
| // If we found one, remove the pointer from the alias set it is in. |
| AliasSet::HashNodePair &PtrValEnt = *I; |
| AliasSet *AS = PtrValEnt.second.getAliasSet(*this); |
| |
| // Unlink from the list of values... |
| PtrValEnt.second.removeFromList(); |
| // Stop using the alias set |
| AS->dropRef(*this); |
| PointerMap.erase(I); |
| } |
| |
| // copyValue - This method should be used whenever a preexisting value in the |
| // program is copied or cloned, introducing a new value. Note that it is ok for |
| // clients that use this method to introduce the same value multiple times: if |
| // the tracker already knows about a value, it will ignore the request. |
| // |
| void AliasSetTracker::copyValue(Value *From, Value *To) { |
| // Notify the alias analysis implementation that this value is copied. |
| AA.copyValue(From, To); |
| |
| // First, look up the PointerRec for this pointer. |
| hash_map<Value*, AliasSet::PointerRec>::iterator I = PointerMap.find(From); |
| if (I == PointerMap.end() || !I->second.hasAliasSet()) |
| return; // Noop |
| |
| AliasSet::HashNodePair &Entry = getEntryFor(To); |
| if (Entry.second.hasAliasSet()) return; // Already in the tracker! |
| |
| // Add it to the alias set it aliases... |
| AliasSet *AS = I->second.getAliasSet(*this); |
| AS->addPointer(*this, Entry, I->second.getSize(), true); |
| } |
| |
| |
| |
| //===----------------------------------------------------------------------===// |
| // AliasSet/AliasSetTracker Printing Support |
| //===----------------------------------------------------------------------===// |
| |
| void AliasSet::print(std::ostream &OS) const { |
| OS << " AliasSet[" << (void*)this << "," << RefCount << "] "; |
| OS << (AliasTy == MustAlias ? "must" : "may ") << " alias, "; |
| switch (AccessTy) { |
| case NoModRef: OS << "No access "; break; |
| case Refs : OS << "Ref "; break; |
| case Mods : OS << "Mod "; break; |
| case ModRef : OS << "Mod/Ref "; break; |
| default: assert(0 && "Bad value for AccessTy!"); |
| } |
| if (isVolatile()) OS << "[volatile] "; |
| if (Forward) |
| OS << " forwarding to " << (void*)Forward; |
| |
| |
| if (begin() != end()) { |
| OS << "Pointers: "; |
| for (iterator I = begin(), E = end(); I != E; ++I) { |
| if (I != begin()) OS << ", "; |
| WriteAsOperand(OS << "(", I.getPointer()); |
| OS << ", " << I.getSize() << ")"; |
| } |
| } |
| if (!CallSites.empty()) { |
| OS << "\n " << CallSites.size() << " Call Sites: "; |
| for (unsigned i = 0, e = CallSites.size(); i != e; ++i) { |
| if (i) OS << ", "; |
| WriteAsOperand(OS, CallSites[i].getCalledValue()); |
| } |
| } |
| OS << "\n"; |
| } |
| |
| void AliasSetTracker::print(std::ostream &OS) const { |
| OS << "Alias Set Tracker: " << AliasSets.size() << " alias sets for " |
| << PointerMap.size() << " pointer values.\n"; |
| for (const_iterator I = begin(), E = end(); I != E; ++I) |
| I->print(OS); |
| OS << "\n"; |
| } |
| |
| void AliasSet::dump() const { print (std::cerr); } |
| void AliasSetTracker::dump() const { print(std::cerr); } |
| |
| //===----------------------------------------------------------------------===// |
| // AliasSetPrinter Pass |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class AliasSetPrinter : public FunctionPass { |
| AliasSetTracker *Tracker; |
| public: |
| virtual void getAnalysisUsage(AnalysisUsage &AU) const { |
| AU.setPreservesAll(); |
| AU.addRequired<AliasAnalysis>(); |
| } |
| |
| virtual bool runOnFunction(Function &F) { |
| Tracker = new AliasSetTracker(getAnalysis<AliasAnalysis>()); |
| |
| for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) |
| Tracker->add(&*I); |
| Tracker->print(std::cerr); |
| delete Tracker; |
| return false; |
| } |
| }; |
| RegisterOpt<AliasSetPrinter> X("print-alias-sets", "Alias Set Printer"); |
| } |