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Diffstat (limited to 'contrib/llvm/lib/Analysis/AliasSetTracker.cpp')
| -rw-r--r-- | contrib/llvm/lib/Analysis/AliasSetTracker.cpp | 653 |
1 files changed, 653 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Analysis/AliasSetTracker.cpp b/contrib/llvm/lib/Analysis/AliasSetTracker.cpp new file mode 100644 index 000000000000..2289c1223e97 --- /dev/null +++ b/contrib/llvm/lib/Analysis/AliasSetTracker.cpp @@ -0,0 +1,653 @@ +//===- AliasSetTracker.cpp - Alias Sets Tracker implementation-------------===// +// +// The LLVM Compiler Infrastructure +// +// This file 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/Assembly/Writer.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/LLVMContext.h" +#include "llvm/IR/Type.h" +#include "llvm/Pass.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/InstIterator.h" +#include "llvm/Support/raw_ostream.h" +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; + Volatile |= AS.Volatile; + + 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(); + PointerRec *L = getSomePointer(); + PointerRec *R = AS.getSomePointer(); + + // If the pointers are not a must-alias pair, this set becomes a may alias. + if (AA.alias(AliasAnalysis::Location(L->getValue(), + L->getSize(), + L->getTBAAInfo()), + AliasAnalysis::Location(R->getValue(), + R->getSize(), + R->getTBAAInfo())) + != AliasAnalysis::MustAlias) + AliasTy = MayAlias; + } + + if (UnknownInsts.empty()) { // Merge call sites... + if (!AS.UnknownInsts.empty()) + std::swap(UnknownInsts, AS.UnknownInsts); + } else if (!AS.UnknownInsts.empty()) { + UnknownInsts.insert(UnknownInsts.end(), AS.UnknownInsts.begin(), AS.UnknownInsts.end()); + AS.UnknownInsts.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->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, PointerRec &Entry, + uint64_t Size, const MDNode *TBAAInfo, + bool KnownMustAlias) { + assert(!Entry.hasAliasSet() && "Entry already in set!"); + + // Check to see if we have to downgrade to _may_ alias. + if (isMustAlias() && !KnownMustAlias) + if (PointerRec *P = getSomePointer()) { + AliasAnalysis &AA = AST.getAliasAnalysis(); + AliasAnalysis::AliasResult Result = + AA.alias(AliasAnalysis::Location(P->getValue(), P->getSize(), + P->getTBAAInfo()), + AliasAnalysis::Location(Entry.getValue(), Size, TBAAInfo)); + if (Result != AliasAnalysis::MustAlias) + AliasTy = MayAlias; + else // First entry of must alias must have maximum size! + P->updateSizeAndTBAAInfo(Size, TBAAInfo); + assert(Result != AliasAnalysis::NoAlias && "Cannot be part of must set!"); + } + + Entry.setAliasSet(this); + Entry.updateSizeAndTBAAInfo(Size, TBAAInfo); + + // Add it to the end of the list... + assert(*PtrListEnd == 0 && "End of list is not null?"); + *PtrListEnd = &Entry; + PtrListEnd = Entry.setPrevInList(PtrListEnd); + assert(*PtrListEnd == 0 && "End of list is not null?"); + addRef(); // Entry points to alias set. +} + +void AliasSet::addUnknownInst(Instruction *I, AliasAnalysis &AA) { + UnknownInsts.push_back(I); + + if (!I->mayWriteToMemory()) { + 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, uint64_t Size, + const MDNode *TBAAInfo, + AliasAnalysis &AA) const { + if (AliasTy == MustAlias) { + assert(UnknownInsts.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. + PointerRec *SomePtr = getSomePointer(); + assert(SomePtr && "Empty must-alias set??"); + return AA.alias(AliasAnalysis::Location(SomePtr->getValue(), + SomePtr->getSize(), + SomePtr->getTBAAInfo()), + AliasAnalysis::Location(Ptr, Size, TBAAInfo)); + } + + // 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(AliasAnalysis::Location(Ptr, Size, TBAAInfo), + AliasAnalysis::Location(I.getPointer(), I.getSize(), + I.getTBAAInfo()))) + return true; + + // Check the unknown instructions... + if (!UnknownInsts.empty()) { + for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i) + if (AA.getModRefInfo(UnknownInsts[i], + AliasAnalysis::Location(Ptr, Size, TBAAInfo)) != + AliasAnalysis::NoModRef) + return true; + } + + return false; +} + +bool AliasSet::aliasesUnknownInst(Instruction *Inst, AliasAnalysis &AA) const { + if (!Inst->mayReadOrWriteMemory()) + return false; + + for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i) { + CallSite C1 = getUnknownInst(i), C2 = Inst; + if (!C1 || !C2 || + AA.getModRefInfo(C1, C2) != AliasAnalysis::NoModRef || + AA.getModRefInfo(C2, C1) != AliasAnalysis::NoModRef) + return true; + } + + for (iterator I = begin(), E = end(); I != E; ++I) + if (AA.getModRefInfo(Inst, AliasAnalysis::Location(I.getPointer(), + I.getSize(), + I.getTBAAInfo())) != + AliasAnalysis::NoModRef) + return true; + + return false; +} + +void AliasSetTracker::clear() { + // Delete all the PointerRec entries. + for (PointerMapType::iterator I = PointerMap.begin(), E = PointerMap.end(); + I != E; ++I) + I->second->eraseFromList(); + + PointerMap.clear(); + + // The alias sets should all be clear now. + AliasSets.clear(); +} + + +/// 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, + uint64_t Size, + const MDNode *TBAAInfo) { + AliasSet *FoundSet = 0; + for (iterator I = begin(), E = end(); I != E; ++I) { + if (I->Forward || !I->aliasesPointer(Ptr, Size, TBAAInfo, AA)) continue; + + 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, uint64_t Size, + const MDNode *TBAAInfo) const { + for (const_iterator I = begin(), E = end(); I != E; ++I) + if (!I->Forward && I->aliasesPointer(Ptr, Size, TBAAInfo, AA)) + return true; + return false; +} + + + +AliasSet *AliasSetTracker::findAliasSetForUnknownInst(Instruction *Inst) { + AliasSet *FoundSet = 0; + for (iterator I = begin(), E = end(); I != E; ++I) { + if (I->Forward || !I->aliasesUnknownInst(Inst, AA)) + continue; + + 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, uint64_t Size, + const MDNode *TBAAInfo, + bool *New) { + AliasSet::PointerRec &Entry = getEntryFor(Pointer); + + // Check to see if the pointer is already known. + if (Entry.hasAliasSet()) { + Entry.updateSizeAndTBAAInfo(Size, TBAAInfo); + // Return the set! + return *Entry.getAliasSet(*this)->getForwardedTarget(*this); + } + + if (AliasSet *AS = findAliasSetForPointer(Pointer, Size, TBAAInfo)) { + // Add it to the alias set it aliases. + AS->addPointer(*this, Entry, Size, TBAAInfo); + return *AS; + } + + 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, TBAAInfo); + return AliasSets.back(); +} + +bool AliasSetTracker::add(Value *Ptr, uint64_t Size, const MDNode *TBAAInfo) { + bool NewPtr; + addPointer(Ptr, Size, TBAAInfo, AliasSet::NoModRef, NewPtr); + return NewPtr; +} + + +bool AliasSetTracker::add(LoadInst *LI) { + if (LI->getOrdering() > Monotonic) return addUnknown(LI); + AliasSet::AccessType ATy = AliasSet::Refs; + bool NewPtr; + AliasSet &AS = addPointer(LI->getOperand(0), + AA.getTypeStoreSize(LI->getType()), + LI->getMetadata(LLVMContext::MD_tbaa), + ATy, NewPtr); + if (LI->isVolatile()) AS.setVolatile(); + return NewPtr; +} + +bool AliasSetTracker::add(StoreInst *SI) { + if (SI->getOrdering() > Monotonic) return addUnknown(SI); + AliasSet::AccessType ATy = AliasSet::Mods; + bool NewPtr; + Value *Val = SI->getOperand(0); + AliasSet &AS = addPointer(SI->getOperand(1), + AA.getTypeStoreSize(Val->getType()), + SI->getMetadata(LLVMContext::MD_tbaa), + ATy, NewPtr); + if (SI->isVolatile()) AS.setVolatile(); + return NewPtr; +} + +bool AliasSetTracker::add(VAArgInst *VAAI) { + bool NewPtr; + addPointer(VAAI->getOperand(0), AliasAnalysis::UnknownSize, + VAAI->getMetadata(LLVMContext::MD_tbaa), + AliasSet::ModRef, NewPtr); + return NewPtr; +} + + +bool AliasSetTracker::addUnknown(Instruction *Inst) { + if (isa<DbgInfoIntrinsic>(Inst)) + return true; // Ignore DbgInfo Intrinsics. + if (!Inst->mayReadOrWriteMemory()) + return true; // doesn't alias anything + + AliasSet *AS = findAliasSetForUnknownInst(Inst); + if (AS) { + AS->addUnknownInst(Inst, AA); + return false; + } + AliasSets.push_back(new AliasSet()); + AS = &AliasSets.back(); + AS->addUnknownInst(Inst, AA); + return true; +} + +bool AliasSetTracker::add(Instruction *I) { + // Dispatch to one of the other add methods. + if (LoadInst *LI = dyn_cast<LoadInst>(I)) + return add(LI); + if (StoreInst *SI = dyn_cast<StoreInst>(I)) + return add(SI); + if (VAArgInst *VAAI = dyn_cast<VAArgInst>(I)) + return add(VAAI); + return addUnknown(I); +} + +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) continue; // 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.UnknownInsts.size(); i != e; ++i) + add(AS.UnknownInsts[i]); + + // Loop over all of the pointers in this alias set. + bool X; + for (AliasSet::iterator ASI = AS.begin(), E = AS.end(); ASI != E; ++ASI) { + AliasSet &NewAS = addPointer(ASI.getPointer(), ASI.getSize(), + ASI.getTBAAInfo(), + (AliasSet::AccessType)AS.AccessTy, X); + if (AS.isVolatile()) NewAS.setVolatile(); + } + } +} + +/// remove - Remove the specified (potentially non-empty) alias set from the +/// tracker. +void AliasSetTracker::remove(AliasSet &AS) { + // Drop all call sites. + AS.UnknownInsts.clear(); + + // Clear the alias set. + unsigned NumRefs = 0; + while (!AS.empty()) { + AliasSet::PointerRec *P = AS.PtrList; + + Value *ValToRemove = P->getValue(); + + // Unlink and delete entry from the list of values. + P->eraseFromList(); + + // Remember how many references need to be dropped. + ++NumRefs; + + // Finally, remove the entry. + PointerMap.erase(ValToRemove); + } + + // Stop using the alias set, removing it. + AS.RefCount -= NumRefs; + if (AS.RefCount == 0) + AS.removeFromTracker(*this); +} + +bool +AliasSetTracker::remove(Value *Ptr, uint64_t Size, const MDNode *TBAAInfo) { + AliasSet *AS = findAliasSetForPointer(Ptr, Size, TBAAInfo); + if (!AS) return false; + remove(*AS); + return true; +} + +bool AliasSetTracker::remove(LoadInst *LI) { + uint64_t Size = AA.getTypeStoreSize(LI->getType()); + const MDNode *TBAAInfo = LI->getMetadata(LLVMContext::MD_tbaa); + AliasSet *AS = findAliasSetForPointer(LI->getOperand(0), Size, TBAAInfo); + if (!AS) return false; + remove(*AS); + return true; +} + +bool AliasSetTracker::remove(StoreInst *SI) { + uint64_t Size = AA.getTypeStoreSize(SI->getOperand(0)->getType()); + const MDNode *TBAAInfo = SI->getMetadata(LLVMContext::MD_tbaa); + AliasSet *AS = findAliasSetForPointer(SI->getOperand(1), Size, TBAAInfo); + if (!AS) return false; + remove(*AS); + return true; +} + +bool AliasSetTracker::remove(VAArgInst *VAAI) { + AliasSet *AS = findAliasSetForPointer(VAAI->getOperand(0), + AliasAnalysis::UnknownSize, + VAAI->getMetadata(LLVMContext::MD_tbaa)); + if (!AS) return false; + remove(*AS); + return true; +} + +bool AliasSetTracker::removeUnknown(Instruction *I) { + if (!I->mayReadOrWriteMemory()) + return false; // doesn't alias anything + + AliasSet *AS = findAliasSetForUnknownInst(I); + 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); + if (StoreInst *SI = dyn_cast<StoreInst>(I)) + return remove(SI); + if (VAArgInst *VAAI = dyn_cast<VAArgInst>(I)) + return remove(VAAI); + return removeUnknown(I); +} + + +// 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); + + // If this is a call instruction, remove the callsite from the appropriate + // AliasSet (if present). + if (Instruction *Inst = dyn_cast<Instruction>(PtrVal)) { + if (Inst->mayReadOrWriteMemory()) { + // Scan all the alias sets to see if this call site is contained. + for (iterator I = begin(), E = end(); I != E; ++I) { + if (I->Forward) continue; + + I->removeUnknownInst(Inst); + } + } + } + + // First, look up the PointerRec for this pointer. + PointerMapType::iterator I = PointerMap.find_as(PtrVal); + if (I == PointerMap.end()) return; // Noop + + // If we found one, remove the pointer from the alias set it is in. + AliasSet::PointerRec *PtrValEnt = I->second; + AliasSet *AS = PtrValEnt->getAliasSet(*this); + + // Unlink and delete from the list of values. + PtrValEnt->eraseFromList(); + + // 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. + PointerMapType::iterator I = PointerMap.find_as(From); + if (I == PointerMap.end()) + return; // Noop + assert(I->second->hasAliasSet() && "Dead entry?"); + + AliasSet::PointerRec &Entry = getEntryFor(To); + if (Entry.hasAliasSet()) return; // Already in the tracker! + + // Add it to the alias set it aliases... + I = PointerMap.find_as(From); + AliasSet *AS = I->second->getAliasSet(*this); + AS->addPointer(*this, Entry, I->second->getSize(), + I->second->getTBAAInfo(), + true); +} + + + +//===----------------------------------------------------------------------===// +// AliasSet/AliasSetTracker Printing Support +//===----------------------------------------------------------------------===// + +void AliasSet::print(raw_ostream &OS) const { + OS << " AliasSet[" << (const 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: llvm_unreachable("Bad value for AccessTy!"); + } + if (isVolatile()) OS << "[volatile] "; + if (Forward) + OS << " forwarding to " << (void*)Forward; + + + if (!empty()) { + OS << "Pointers: "; + for (iterator I = begin(), E = end(); I != E; ++I) { + if (I != begin()) OS << ", "; + WriteAsOperand(OS << "(", I.getPointer()); + OS << ", " << I.getSize() << ")"; + } + } + if (!UnknownInsts.empty()) { + OS << "\n " << UnknownInsts.size() << " Unknown instructions: "; + for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i) { + if (i) OS << ", "; + WriteAsOperand(OS, UnknownInsts[i]); + } + } + OS << "\n"; +} + +void AliasSetTracker::print(raw_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"; +} + +#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) +void AliasSet::dump() const { print(dbgs()); } +void AliasSetTracker::dump() const { print(dbgs()); } +#endif + +//===----------------------------------------------------------------------===// +// ASTCallbackVH Class Implementation +//===----------------------------------------------------------------------===// + +void AliasSetTracker::ASTCallbackVH::deleted() { + assert(AST && "ASTCallbackVH called with a null AliasSetTracker!"); + AST->deleteValue(getValPtr()); + // this now dangles! +} + +void AliasSetTracker::ASTCallbackVH::allUsesReplacedWith(Value *V) { + AST->copyValue(getValPtr(), V); +} + +AliasSetTracker::ASTCallbackVH::ASTCallbackVH(Value *V, AliasSetTracker *ast) + : CallbackVH(V), AST(ast) {} + +AliasSetTracker::ASTCallbackVH & +AliasSetTracker::ASTCallbackVH::operator=(Value *V) { + return *this = ASTCallbackVH(V, AST); +} + +//===----------------------------------------------------------------------===// +// AliasSetPrinter Pass +//===----------------------------------------------------------------------===// + +namespace { + class AliasSetPrinter : public FunctionPass { + AliasSetTracker *Tracker; + public: + static char ID; // Pass identification, replacement for typeid + AliasSetPrinter() : FunctionPass(ID) { + initializeAliasSetPrinterPass(*PassRegistry::getPassRegistry()); + } + + 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(errs()); + delete Tracker; + return false; + } + }; +} + +char AliasSetPrinter::ID = 0; +INITIALIZE_PASS_BEGIN(AliasSetPrinter, "print-alias-sets", + "Alias Set Printer", false, true) +INITIALIZE_AG_DEPENDENCY(AliasAnalysis) +INITIALIZE_PASS_END(AliasSetPrinter, "print-alias-sets", + "Alias Set Printer", false, true) |