X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FAnalysis%2FAliasAnalysis.cpp;h=0fef5c666511d86f32b4ea1e65fc7ba9d342f31e;hp=752edd52b454fb3d9e55a2f1c727b3834d77b6e2;hb=198a6c5be5990008347b191f3cdd5713e3463cd6;hpb=3e2d76c946ba753c2b11af192a52e25b6f9b46ff diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp index 752edd52b45..0fef5c66651 100644 --- a/lib/Analysis/AliasAnalysis.cpp +++ b/lib/Analysis/AliasAnalysis.cpp @@ -25,401 +25,287 @@ //===----------------------------------------------------------------------===// #include "llvm/Analysis/AliasAnalysis.h" +#include "llvm/Analysis/BasicAliasAnalysis.h" +#include "llvm/Analysis/CFG.h" +#include "llvm/Analysis/CFLAliasAnalysis.h" #include "llvm/Analysis/CaptureTracking.h" -#include "llvm/Analysis/Dominators.h" +#include "llvm/Analysis/GlobalsModRef.h" +#include "llvm/Analysis/ObjCARCAliasAnalysis.h" +#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h" +#include "llvm/Analysis/ScopedNoAliasAA.h" +#include "llvm/Analysis/TargetLibraryInfo.h" +#include "llvm/Analysis/TypeBasedAliasAnalysis.h" #include "llvm/Analysis/ValueTracking.h" +#include "llvm/IR/BasicBlock.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/Dominators.h" +#include "llvm/IR/Function.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/BasicBlock.h" -#include "llvm/Function.h" -#include "llvm/IntrinsicInst.h" -#include "llvm/Instructions.h" -#include "llvm/LLVMContext.h" -#include "llvm/Type.h" -#include "llvm/DataLayout.h" -#include "llvm/Target/TargetLibraryInfo.h" using namespace llvm; -// Register the AliasAnalysis interface, providing a nice name to refer to. -INITIALIZE_ANALYSIS_GROUP(AliasAnalysis, "Alias Analysis", NoAA) -char AliasAnalysis::ID = 0; +/// Allow disabling BasicAA from the AA results. This is particularly useful +/// when testing to isolate a single AA implementation. +static cl::opt DisableBasicAA("disable-basicaa", cl::Hidden, + cl::init(false)); -//===----------------------------------------------------------------------===// -// Default chaining methods -//===----------------------------------------------------------------------===// - -AliasAnalysis::AliasResult -AliasAnalysis::alias(const Location &LocA, const Location &LocB) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); - return AA->alias(LocA, LocB); +AAResults::AAResults(AAResults &&Arg) : AAs(std::move(Arg.AAs)) { + for (auto &AA : AAs) + AA->setAAResults(this); } -bool AliasAnalysis::pointsToConstantMemory(const Location &Loc, - bool OrLocal) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); - return AA->pointsToConstantMemory(Loc, OrLocal); +AAResults &AAResults::operator=(AAResults &&Arg) { + AAs = std::move(Arg.AAs); + for (auto &AA : AAs) + AA->setAAResults(this); + return *this; } -void AliasAnalysis::deleteValue(Value *V) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); - AA->deleteValue(V); -} - -void AliasAnalysis::copyValue(Value *From, Value *To) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); - AA->copyValue(From, To); -} - -void AliasAnalysis::addEscapingUse(Use &U) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); - AA->addEscapingUse(U); +AAResults::~AAResults() { +// FIXME; It would be nice to at least clear out the pointers back to this +// aggregation here, but we end up with non-nesting lifetimes in the legacy +// pass manager that prevent this from working. In the legacy pass manager +// we'll end up with dangling references here in some cases. +#if 0 + for (auto &AA : AAs) + AA->setAAResults(nullptr); +#endif } +//===----------------------------------------------------------------------===// +// Default chaining methods +//===----------------------------------------------------------------------===// -AliasAnalysis::ModRefResult -AliasAnalysis::getModRefInfo(ImmutableCallSite CS, - const Location &Loc) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); - - ModRefBehavior MRB = getModRefBehavior(CS); - if (MRB == DoesNotAccessMemory) - return NoModRef; - - ModRefResult Mask = ModRef; - if (onlyReadsMemory(MRB)) - Mask = Ref; - - if (onlyAccessesArgPointees(MRB)) { - bool doesAlias = false; - if (doesAccessArgPointees(MRB)) { - MDNode *CSTag = CS.getInstruction()->getMetadata(LLVMContext::MD_tbaa); - for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end(); - AI != AE; ++AI) { - const Value *Arg = *AI; - if (!Arg->getType()->isPointerTy()) - continue; - Location CSLoc(Arg, UnknownSize, CSTag); - if (!isNoAlias(CSLoc, Loc)) { - doesAlias = true; - break; - } - } - } - if (!doesAlias) - return NoModRef; +AliasResult AAResults::alias(const MemoryLocation &LocA, + const MemoryLocation &LocB) { + for (const auto &AA : AAs) { + auto Result = AA->alias(LocA, LocB); + if (Result != MayAlias) + return Result; } + return MayAlias; +} - // If Loc is a constant memory location, the call definitely could not - // modify the memory location. - if ((Mask & Mod) && pointsToConstantMemory(Loc)) - Mask = ModRefResult(Mask & ~Mod); - - // If this is the end of the chain, don't forward. - if (!AA) return Mask; +bool AAResults::pointsToConstantMemory(const MemoryLocation &Loc, + bool OrLocal) { + for (const auto &AA : AAs) + if (AA->pointsToConstantMemory(Loc, OrLocal)) + return true; - // Otherwise, fall back to the next AA in the chain. But we can merge - // in any mask we've managed to compute. - return ModRefResult(AA->getModRefInfo(CS, Loc) & Mask); + return false; } -AliasAnalysis::ModRefResult -AliasAnalysis::getModRefInfo(ImmutableCallSite CS1, ImmutableCallSite CS2) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); - - // If CS1 or CS2 are readnone, they don't interact. - ModRefBehavior CS1B = getModRefBehavior(CS1); - if (CS1B == DoesNotAccessMemory) return NoModRef; - - ModRefBehavior CS2B = getModRefBehavior(CS2); - if (CS2B == DoesNotAccessMemory) return NoModRef; - - // If they both only read from memory, there is no dependence. - if (onlyReadsMemory(CS1B) && onlyReadsMemory(CS2B)) - return NoModRef; - - AliasAnalysis::ModRefResult Mask = ModRef; - - // If CS1 only reads memory, the only dependence on CS2 can be - // from CS1 reading memory written by CS2. - if (onlyReadsMemory(CS1B)) - Mask = ModRefResult(Mask & Ref); - - // If CS2 only access memory through arguments, accumulate the mod/ref - // information from CS1's references to the memory referenced by - // CS2's arguments. - if (onlyAccessesArgPointees(CS2B)) { - AliasAnalysis::ModRefResult R = NoModRef; - if (doesAccessArgPointees(CS2B)) { - MDNode *CS2Tag = CS2.getInstruction()->getMetadata(LLVMContext::MD_tbaa); - for (ImmutableCallSite::arg_iterator - I = CS2.arg_begin(), E = CS2.arg_end(); I != E; ++I) { - const Value *Arg = *I; - if (!Arg->getType()->isPointerTy()) - continue; - Location CS2Loc(Arg, UnknownSize, CS2Tag); - R = ModRefResult((R | getModRefInfo(CS1, CS2Loc)) & Mask); - if (R == Mask) - break; - } - } - return R; - } +ModRefInfo AAResults::getArgModRefInfo(ImmutableCallSite CS, unsigned ArgIdx) { + ModRefInfo Result = MRI_ModRef; - // If CS1 only accesses memory through arguments, check if CS2 references - // any of the memory referenced by CS1's arguments. If not, return NoModRef. - if (onlyAccessesArgPointees(CS1B)) { - AliasAnalysis::ModRefResult R = NoModRef; - if (doesAccessArgPointees(CS1B)) { - MDNode *CS1Tag = CS1.getInstruction()->getMetadata(LLVMContext::MD_tbaa); - for (ImmutableCallSite::arg_iterator - I = CS1.arg_begin(), E = CS1.arg_end(); I != E; ++I) { - const Value *Arg = *I; - if (!Arg->getType()->isPointerTy()) - continue; - Location CS1Loc(Arg, UnknownSize, CS1Tag); - if (getModRefInfo(CS2, CS1Loc) != NoModRef) { - R = Mask; - break; - } - } - } - if (R == NoModRef) - return R; - } + for (const auto &AA : AAs) { + Result = ModRefInfo(Result & AA->getArgModRefInfo(CS, ArgIdx)); - // If this is the end of the chain, don't forward. - if (!AA) return Mask; + // Early-exit the moment we reach the bottom of the lattice. + if (Result == MRI_NoModRef) + return Result; + } - // Otherwise, fall back to the next AA in the chain. But we can merge - // in any mask we've managed to compute. - return ModRefResult(AA->getModRefInfo(CS1, CS2) & Mask); + return Result; } -AliasAnalysis::ModRefBehavior -AliasAnalysis::getModRefBehavior(ImmutableCallSite CS) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); +ModRefInfo AAResults::getModRefInfo(Instruction *I, ImmutableCallSite Call) { + // We may have two calls + if (auto CS = ImmutableCallSite(I)) { + // Check if the two calls modify the same memory + return getModRefInfo(Call, CS); + } else { + // Otherwise, check if the call modifies or references the + // location this memory access defines. The best we can say + // is that if the call references what this instruction + // defines, it must be clobbered by this location. + const MemoryLocation DefLoc = MemoryLocation::get(I); + if (getModRefInfo(Call, DefLoc) != MRI_NoModRef) + return MRI_ModRef; + } + return MRI_NoModRef; +} - ModRefBehavior Min = UnknownModRefBehavior; +ModRefInfo AAResults::getModRefInfo(ImmutableCallSite CS, + const MemoryLocation &Loc) { + ModRefInfo Result = MRI_ModRef; - // Call back into the alias analysis with the other form of getModRefBehavior - // to see if it can give a better response. - if (const Function *F = CS.getCalledFunction()) - Min = getModRefBehavior(F); + for (const auto &AA : AAs) { + Result = ModRefInfo(Result & AA->getModRefInfo(CS, Loc)); - // If this is the end of the chain, don't forward. - if (!AA) return Min; + // Early-exit the moment we reach the bottom of the lattice. + if (Result == MRI_NoModRef) + return Result; + } - // Otherwise, fall back to the next AA in the chain. But we can merge - // in any result we've managed to compute. - return ModRefBehavior(AA->getModRefBehavior(CS) & Min); + return Result; } -AliasAnalysis::ModRefBehavior -AliasAnalysis::getModRefBehavior(const Function *F) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); - return AA->getModRefBehavior(F); -} +ModRefInfo AAResults::getModRefInfo(ImmutableCallSite CS1, + ImmutableCallSite CS2) { + ModRefInfo Result = MRI_ModRef; -//===----------------------------------------------------------------------===// -// AliasAnalysis non-virtual helper method implementation -//===----------------------------------------------------------------------===// + for (const auto &AA : AAs) { + Result = ModRefInfo(Result & AA->getModRefInfo(CS1, CS2)); -AliasAnalysis::Location AliasAnalysis::getLocation(const LoadInst *LI) { - return Location(LI->getPointerOperand(), - getTypeStoreSize(LI->getType()), - LI->getMetadata(LLVMContext::MD_tbaa)); -} + // Early-exit the moment we reach the bottom of the lattice. + if (Result == MRI_NoModRef) + return Result; + } -AliasAnalysis::Location AliasAnalysis::getLocation(const StoreInst *SI) { - return Location(SI->getPointerOperand(), - getTypeStoreSize(SI->getValueOperand()->getType()), - SI->getMetadata(LLVMContext::MD_tbaa)); + return Result; } -AliasAnalysis::Location AliasAnalysis::getLocation(const VAArgInst *VI) { - return Location(VI->getPointerOperand(), - UnknownSize, - VI->getMetadata(LLVMContext::MD_tbaa)); -} +FunctionModRefBehavior AAResults::getModRefBehavior(ImmutableCallSite CS) { + FunctionModRefBehavior Result = FMRB_UnknownModRefBehavior; -AliasAnalysis::Location -AliasAnalysis::getLocation(const AtomicCmpXchgInst *CXI) { - return Location(CXI->getPointerOperand(), - getTypeStoreSize(CXI->getCompareOperand()->getType()), - CXI->getMetadata(LLVMContext::MD_tbaa)); -} + for (const auto &AA : AAs) { + Result = FunctionModRefBehavior(Result & AA->getModRefBehavior(CS)); + + // Early-exit the moment we reach the bottom of the lattice. + if (Result == FMRB_DoesNotAccessMemory) + return Result; + } -AliasAnalysis::Location -AliasAnalysis::getLocation(const AtomicRMWInst *RMWI) { - return Location(RMWI->getPointerOperand(), - getTypeStoreSize(RMWI->getValOperand()->getType()), - RMWI->getMetadata(LLVMContext::MD_tbaa)); + return Result; } -AliasAnalysis::Location -AliasAnalysis::getLocationForSource(const MemTransferInst *MTI) { - uint64_t Size = UnknownSize; - if (ConstantInt *C = dyn_cast(MTI->getLength())) - Size = C->getValue().getZExtValue(); +FunctionModRefBehavior AAResults::getModRefBehavior(const Function *F) { + FunctionModRefBehavior Result = FMRB_UnknownModRefBehavior; - // memcpy/memmove can have TBAA tags. For memcpy, they apply - // to both the source and the destination. - MDNode *TBAATag = MTI->getMetadata(LLVMContext::MD_tbaa); + for (const auto &AA : AAs) { + Result = FunctionModRefBehavior(Result & AA->getModRefBehavior(F)); - return Location(MTI->getRawSource(), Size, TBAATag); -} + // Early-exit the moment we reach the bottom of the lattice. + if (Result == FMRB_DoesNotAccessMemory) + return Result; + } -AliasAnalysis::Location -AliasAnalysis::getLocationForDest(const MemIntrinsic *MTI) { - uint64_t Size = UnknownSize; - if (ConstantInt *C = dyn_cast(MTI->getLength())) - Size = C->getValue().getZExtValue(); - - // memcpy/memmove can have TBAA tags. For memcpy, they apply - // to both the source and the destination. - MDNode *TBAATag = MTI->getMetadata(LLVMContext::MD_tbaa); - - return Location(MTI->getRawDest(), Size, TBAATag); + return Result; } +//===----------------------------------------------------------------------===// +// Helper method implementation +//===----------------------------------------------------------------------===// - -AliasAnalysis::ModRefResult -AliasAnalysis::getModRefInfo(const LoadInst *L, const Location &Loc) { +ModRefInfo AAResults::getModRefInfo(const LoadInst *L, + const MemoryLocation &Loc) { // Be conservative in the face of volatile/atomic. if (!L->isUnordered()) - return ModRef; + return MRI_ModRef; // If the load address doesn't alias the given address, it doesn't read // or write the specified memory. - if (!alias(getLocation(L), Loc)) - return NoModRef; + if (Loc.Ptr && !alias(MemoryLocation::get(L), Loc)) + return MRI_NoModRef; // Otherwise, a load just reads. - return Ref; + return MRI_Ref; } -AliasAnalysis::ModRefResult -AliasAnalysis::getModRefInfo(const StoreInst *S, const Location &Loc) { +ModRefInfo AAResults::getModRefInfo(const StoreInst *S, + const MemoryLocation &Loc) { // Be conservative in the face of volatile/atomic. if (!S->isUnordered()) - return ModRef; - - // If the store address cannot alias the pointer in question, then the - // specified memory cannot be modified by the store. - if (!alias(getLocation(S), Loc)) - return NoModRef; - - // If the pointer is a pointer to constant memory, then it could not have been - // modified by this store. - if (pointsToConstantMemory(Loc)) - return NoModRef; + return MRI_ModRef; + + if (Loc.Ptr) { + // If the store address cannot alias the pointer in question, then the + // specified memory cannot be modified by the store. + if (!alias(MemoryLocation::get(S), Loc)) + return MRI_NoModRef; + + // If the pointer is a pointer to constant memory, then it could not have + // been modified by this store. + if (pointsToConstantMemory(Loc)) + return MRI_NoModRef; + } // Otherwise, a store just writes. - return Mod; + return MRI_Mod; } -AliasAnalysis::ModRefResult -AliasAnalysis::getModRefInfo(const VAArgInst *V, const Location &Loc) { - // If the va_arg address cannot alias the pointer in question, then the - // specified memory cannot be accessed by the va_arg. - if (!alias(getLocation(V), Loc)) - return NoModRef; +ModRefInfo AAResults::getModRefInfo(const VAArgInst *V, + const MemoryLocation &Loc) { + + if (Loc.Ptr) { + // If the va_arg address cannot alias the pointer in question, then the + // specified memory cannot be accessed by the va_arg. + if (!alias(MemoryLocation::get(V), Loc)) + return MRI_NoModRef; - // If the pointer is a pointer to constant memory, then it could not have been - // modified by this va_arg. - if (pointsToConstantMemory(Loc)) - return NoModRef; + // If the pointer is a pointer to constant memory, then it could not have + // been modified by this va_arg. + if (pointsToConstantMemory(Loc)) + return MRI_NoModRef; + } // Otherwise, a va_arg reads and writes. - return ModRef; + return MRI_ModRef; } -AliasAnalysis::ModRefResult -AliasAnalysis::getModRefInfo(const AtomicCmpXchgInst *CX, const Location &Loc) { +ModRefInfo AAResults::getModRefInfo(const AtomicCmpXchgInst *CX, + const MemoryLocation &Loc) { // Acquire/Release cmpxchg has properties that matter for arbitrary addresses. - if (CX->getOrdering() > Monotonic) - return ModRef; + if (CX->getSuccessOrdering() > Monotonic) + return MRI_ModRef; // If the cmpxchg address does not alias the location, it does not access it. - if (!alias(getLocation(CX), Loc)) - return NoModRef; + if (Loc.Ptr && !alias(MemoryLocation::get(CX), Loc)) + return MRI_NoModRef; - return ModRef; + return MRI_ModRef; } -AliasAnalysis::ModRefResult -AliasAnalysis::getModRefInfo(const AtomicRMWInst *RMW, const Location &Loc) { +ModRefInfo AAResults::getModRefInfo(const AtomicRMWInst *RMW, + const MemoryLocation &Loc) { // Acquire/Release atomicrmw has properties that matter for arbitrary addresses. if (RMW->getOrdering() > Monotonic) - return ModRef; + return MRI_ModRef; // If the atomicrmw address does not alias the location, it does not access it. - if (!alias(getLocation(RMW), Loc)) - return NoModRef; + if (Loc.Ptr && !alias(MemoryLocation::get(RMW), Loc)) + return MRI_NoModRef; - return ModRef; + return MRI_ModRef; } -namespace { - /// Only find pointer captures which happen before the given instruction. Uses - /// the dominator tree to determine whether one instruction is before another. - struct CapturesBefore : public CaptureTracker { - CapturesBefore(const Instruction *I, DominatorTree *DT) - : BeforeHere(I), DT(DT), Captured(false) {} - - void tooManyUses() { Captured = true; } - - bool shouldExplore(Use *U) { - Instruction *I = cast(U->getUser()); - BasicBlock *BB = I->getParent(); - if (BeforeHere != I && - (!DT->isReachableFromEntry(BB) || DT->dominates(BeforeHere, I))) - return false; - return true; - } - - bool captured(Use *U) { - Instruction *I = cast(U->getUser()); - BasicBlock *BB = I->getParent(); - if (BeforeHere != I && - (!DT->isReachableFromEntry(BB) || DT->dominates(BeforeHere, I))) - return false; - Captured = true; - return true; - } - - const Instruction *BeforeHere; - DominatorTree *DT; - - bool Captured; - }; -} - -// FIXME: this is really just shoring-up a deficiency in alias analysis. -// BasicAA isn't willing to spend linear time determining whether an alloca -// was captured before or after this particular call, while we are. However, -// with a smarter AA in place, this test is just wasting compile time. -AliasAnalysis::ModRefResult -AliasAnalysis::callCapturesBefore(const Instruction *I, - const AliasAnalysis::Location &MemLoc, - DominatorTree *DT) { - if (!DT || !TD) return AliasAnalysis::ModRef; - - const Value *Object = GetUnderlyingObject(MemLoc.Ptr, TD); +/// \brief Return information about whether a particular call site modifies +/// or reads the specified memory location \p MemLoc before instruction \p I +/// in a BasicBlock. A ordered basic block \p OBB can be used to speed up +/// instruction-ordering queries inside the BasicBlock containing \p I. +/// FIXME: this is really just shoring-up a deficiency in alias analysis. +/// BasicAA isn't willing to spend linear time determining whether an alloca +/// was captured before or after this particular call, while we are. However, +/// with a smarter AA in place, this test is just wasting compile time. +ModRefInfo AAResults::callCapturesBefore(const Instruction *I, + const MemoryLocation &MemLoc, + DominatorTree *DT, + OrderedBasicBlock *OBB) { + if (!DT) + return MRI_ModRef; + + const Value *Object = + GetUnderlyingObject(MemLoc.Ptr, I->getModule()->getDataLayout()); if (!isIdentifiedObject(Object) || isa(Object) || isa(Object)) - return AliasAnalysis::ModRef; + return MRI_ModRef; ImmutableCallSite CS(I); if (!CS.getInstruction() || CS.getInstruction() == Object) - return AliasAnalysis::ModRef; + return MRI_ModRef; - CapturesBefore CB(I, DT); - llvm::PointerMayBeCaptured(Object, &CB); - if (CB.Captured) - return AliasAnalysis::ModRef; + if (llvm::PointerMayBeCapturedBefore(Object, /* ReturnCaptures */ true, + /* StoreCaptures */ true, I, DT, + /* include Object */ true, + /* OrderedBasicBlock */ OBB)) + return MRI_ModRef; unsigned ArgNo = 0; + ModRefInfo R = MRI_NoModRef; for (ImmutableCallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end(); CI != CE; ++CI, ++ArgNo) { // Only look at the no-capture or byval pointer arguments. If this @@ -433,77 +319,213 @@ AliasAnalysis::callCapturesBefore(const Instruction *I, // is impossible to alias the pointer we're checking. If not, we have to // assume that the call could touch the pointer, even though it doesn't // escape. - if (!isNoAlias(AliasAnalysis::Location(*CI), - AliasAnalysis::Location(Object))) { - return AliasAnalysis::ModRef; + if (isNoAlias(MemoryLocation(*CI), MemoryLocation(Object))) + continue; + if (CS.doesNotAccessMemory(ArgNo)) + continue; + if (CS.onlyReadsMemory(ArgNo)) { + R = MRI_Ref; + continue; } + return MRI_ModRef; } - return AliasAnalysis::NoModRef; -} - -// AliasAnalysis destructor: DO NOT move this to the header file for -// AliasAnalysis or else clients of the AliasAnalysis class may not depend on -// the AliasAnalysis.o file in the current .a file, causing alias analysis -// support to not be included in the tool correctly! -// -AliasAnalysis::~AliasAnalysis() {} - -/// InitializeAliasAnalysis - Subclasses must call this method to initialize the -/// AliasAnalysis interface before any other methods are called. -/// -void AliasAnalysis::InitializeAliasAnalysis(Pass *P) { - TD = P->getAnalysisIfAvailable(); - TLI = P->getAnalysisIfAvailable(); - AA = &P->getAnalysis(); -} - -// getAnalysisUsage - All alias analysis implementations should invoke this -// directly (using AliasAnalysis::getAnalysisUsage(AU)). -void AliasAnalysis::getAnalysisUsage(AnalysisUsage &AU) const { - AU.addRequired(); // All AA's chain -} - -/// getTypeStoreSize - Return the DataLayout store size for the given type, -/// if known, or a conservative value otherwise. -/// -uint64_t AliasAnalysis::getTypeStoreSize(Type *Ty) { - return TD ? TD->getTypeStoreSize(Ty) : UnknownSize; + return R; } /// canBasicBlockModify - Return true if it is possible for execution of the -/// specified basic block to modify the value pointed to by Ptr. +/// specified basic block to modify the location Loc. /// -bool AliasAnalysis::canBasicBlockModify(const BasicBlock &BB, - const Location &Loc) { - return canInstructionRangeModify(BB.front(), BB.back(), Loc); +bool AAResults::canBasicBlockModify(const BasicBlock &BB, + const MemoryLocation &Loc) { + return canInstructionRangeModRef(BB.front(), BB.back(), Loc, MRI_Mod); } -/// canInstructionRangeModify - Return true if it is possible for the execution -/// of the specified instructions to modify the value pointed to by Ptr. The -/// instructions to consider are all of the instructions in the range of [I1,I2] -/// INCLUSIVE. I1 and I2 must be in the same basic block. -/// -bool AliasAnalysis::canInstructionRangeModify(const Instruction &I1, - const Instruction &I2, - const Location &Loc) { +/// canInstructionRangeModRef - Return true if it is possible for the +/// execution of the specified instructions to mod\ref (according to the +/// mode) the location Loc. The instructions to consider are all +/// of the instructions in the range of [I1,I2] INCLUSIVE. +/// I1 and I2 must be in the same basic block. +bool AAResults::canInstructionRangeModRef(const Instruction &I1, + const Instruction &I2, + const MemoryLocation &Loc, + const ModRefInfo Mode) { assert(I1.getParent() == I2.getParent() && "Instructions not in same basic block!"); - BasicBlock::const_iterator I = &I1; - BasicBlock::const_iterator E = &I2; + BasicBlock::const_iterator I = I1.getIterator(); + BasicBlock::const_iterator E = I2.getIterator(); ++E; // Convert from inclusive to exclusive range. for (; I != E; ++I) // Check every instruction in range - if (getModRefInfo(I, Loc) & Mod) + if (getModRefInfo(&*I, Loc) & Mode) return true; return false; } +// Provide a definition for the root virtual destructor. +AAResults::Concept::~Concept() {} + +namespace { +/// A wrapper pass for external alias analyses. This just squirrels away the +/// callback used to run any analyses and register their results. +struct ExternalAAWrapperPass : ImmutablePass { + typedef std::function CallbackT; + + CallbackT CB; + + static char ID; + + ExternalAAWrapperPass() : ImmutablePass(ID) { + initializeExternalAAWrapperPassPass(*PassRegistry::getPassRegistry()); + } + explicit ExternalAAWrapperPass(CallbackT CB) + : ImmutablePass(ID), CB(std::move(CB)) { + initializeExternalAAWrapperPassPass(*PassRegistry::getPassRegistry()); + } + + void getAnalysisUsage(AnalysisUsage &AU) const override { + AU.setPreservesAll(); + } +}; +} + +char ExternalAAWrapperPass::ID = 0; +INITIALIZE_PASS(ExternalAAWrapperPass, "external-aa", "External Alias Analysis", + false, true) + +ImmutablePass * +llvm::createExternalAAWrapperPass(ExternalAAWrapperPass::CallbackT Callback) { + return new ExternalAAWrapperPass(std::move(Callback)); +} + +AAResultsWrapperPass::AAResultsWrapperPass() : FunctionPass(ID) { + initializeAAResultsWrapperPassPass(*PassRegistry::getPassRegistry()); +} + +char AAResultsWrapperPass::ID = 0; + +INITIALIZE_PASS_BEGIN(AAResultsWrapperPass, "aa", + "Function Alias Analysis Results", false, true) +INITIALIZE_PASS_DEPENDENCY(BasicAAWrapperPass) +INITIALIZE_PASS_DEPENDENCY(CFLAAWrapperPass) +INITIALIZE_PASS_DEPENDENCY(ExternalAAWrapperPass) +INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass) +INITIALIZE_PASS_DEPENDENCY(ObjCARCAAWrapperPass) +INITIALIZE_PASS_DEPENDENCY(SCEVAAWrapperPass) +INITIALIZE_PASS_DEPENDENCY(ScopedNoAliasAAWrapperPass) +INITIALIZE_PASS_DEPENDENCY(TypeBasedAAWrapperPass) +INITIALIZE_PASS_END(AAResultsWrapperPass, "aa", + "Function Alias Analysis Results", false, true) + +FunctionPass *llvm::createAAResultsWrapperPass() { + return new AAResultsWrapperPass(); +} + +/// Run the wrapper pass to rebuild an aggregation over known AA passes. +/// +/// This is the legacy pass manager's interface to the new-style AA results +/// aggregation object. Because this is somewhat shoe-horned into the legacy +/// pass manager, we hard code all the specific alias analyses available into +/// it. While the particular set enabled is configured via commandline flags, +/// adding a new alias analysis to LLVM will require adding support for it to +/// this list. +bool AAResultsWrapperPass::runOnFunction(Function &F) { + // NB! This *must* be reset before adding new AA results to the new + // AAResults object because in the legacy pass manager, each instance + // of these will refer to the *same* immutable analyses, registering and + // unregistering themselves with them. We need to carefully tear down the + // previous object first, in this case replacing it with an empty one, before + // registering new results. + AAR.reset(new AAResults()); + + // BasicAA is always available for function analyses. Also, we add it first + // so that it can trump TBAA results when it proves MustAlias. + // FIXME: TBAA should have an explicit mode to support this and then we + // should reconsider the ordering here. + if (!DisableBasicAA) + AAR->addAAResult(getAnalysis().getResult()); + + // Populate the results with the currently available AAs. + if (auto *WrapperPass = getAnalysisIfAvailable()) + AAR->addAAResult(WrapperPass->getResult()); + if (auto *WrapperPass = getAnalysisIfAvailable()) + AAR->addAAResult(WrapperPass->getResult()); + if (auto *WrapperPass = + getAnalysisIfAvailable()) + AAR->addAAResult(WrapperPass->getResult()); + if (auto *WrapperPass = getAnalysisIfAvailable()) + AAR->addAAResult(WrapperPass->getResult()); + if (auto *WrapperPass = getAnalysisIfAvailable()) + AAR->addAAResult(WrapperPass->getResult()); + if (auto *WrapperPass = getAnalysisIfAvailable()) + AAR->addAAResult(WrapperPass->getResult()); + + // If available, run an external AA providing callback over the results as + // well. + if (auto *WrapperPass = getAnalysisIfAvailable()) + if (WrapperPass->CB) + WrapperPass->CB(*this, F, *AAR); + + // Analyses don't mutate the IR, so return false. + return false; +} + +void AAResultsWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const { + AU.setPreservesAll(); + AU.addRequired(); + + // We also need to mark all the alias analysis passes we will potentially + // probe in runOnFunction as used here to ensure the legacy pass manager + // preserves them. This hard coding of lists of alias analyses is specific to + // the legacy pass manager. + AU.addUsedIfAvailable(); + AU.addUsedIfAvailable(); + AU.addUsedIfAvailable(); + AU.addUsedIfAvailable(); + AU.addUsedIfAvailable(); + AU.addUsedIfAvailable(); +} + +AAResults llvm::createLegacyPMAAResults(Pass &P, Function &F, + BasicAAResult &BAR) { + AAResults AAR; + + // Add in our explicitly constructed BasicAA results. + if (!DisableBasicAA) + AAR.addAAResult(BAR); + + // Populate the results with the other currently available AAs. + if (auto *WrapperPass = + P.getAnalysisIfAvailable()) + AAR.addAAResult(WrapperPass->getResult()); + if (auto *WrapperPass = P.getAnalysisIfAvailable()) + AAR.addAAResult(WrapperPass->getResult()); + if (auto *WrapperPass = + P.getAnalysisIfAvailable()) + AAR.addAAResult(WrapperPass->getResult()); + if (auto *WrapperPass = P.getAnalysisIfAvailable()) + AAR.addAAResult(WrapperPass->getResult()); + if (auto *WrapperPass = P.getAnalysisIfAvailable()) + AAR.addAAResult(WrapperPass->getResult()); + if (auto *WrapperPass = P.getAnalysisIfAvailable()) + AAR.addAAResult(WrapperPass->getResult()); + + return AAR; +} + /// isNoAliasCall - Return true if this pointer is returned by a noalias /// function. bool llvm::isNoAliasCall(const Value *V) { - if (isa(V) || isa(V)) - return ImmutableCallSite(cast(V)) - .paramHasAttr(0, Attributes::NoAlias); + if (auto CS = ImmutableCallSite(V)) + return CS.paramHasAttr(0, Attribute::NoAlias); + return false; +} + +/// isNoAliasArgument - Return true if this is an argument with the noalias +/// attribute. +bool llvm::isNoAliasArgument(const Value *V) +{ + if (const Argument *A = dyn_cast(V)) + return A->hasNoAliasAttr(); return false; } @@ -526,18 +548,12 @@ bool llvm::isIdentifiedObject(const Value *V) { return false; } -/// isKnownNonNull - Return true if we know that the specified value is never -/// null. -bool llvm::isKnownNonNull(const Value *V) { - // Alloca never returns null, malloc might. - if (isa(V)) return true; - - // A byval argument is never null. - if (const Argument *A = dyn_cast(V)) - return A->hasByValAttr(); - - // Global values are not null unless extern weak. - if (const GlobalValue *GV = dyn_cast(V)) - return !GV->hasExternalWeakLinkage(); - return false; +/// isIdentifiedFunctionLocal - Return true if V is umabigously identified +/// at the function-level. Different IdentifiedFunctionLocals can't alias. +/// Further, an IdentifiedFunctionLocal can not alias with any function +/// arguments other than itself, which is not necessarily true for +/// IdentifiedObjects. +bool llvm::isIdentifiedFunctionLocal(const Value *V) +{ + return isa(V) || isNoAliasCall(V) || isNoAliasArgument(V); }