X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FAliasAnalysis.cpp;h=35f2e97622fa276e8872565e590e49e0bd107713;hb=bef6034cc2b3c10c7762d8aa7831bf4b44d56854;hp=ab12b0df31d826b014c5dd5f6f20a09850dc23eb;hpb=081c34b725980f995be9080eaec24cd3dfaaf065;p=oota-llvm.git diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp index ab12b0df31d..35f2e97622f 100644 --- a/lib/Analysis/AliasAnalysis.cpp +++ b/lib/Analysis/AliasAnalysis.cpp @@ -25,302 +25,533 @@ //===----------------------------------------------------------------------===// #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/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/Target/TargetData.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) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); - return AA->pointsToConstantMemory(Loc); +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); +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 } -void AliasAnalysis::copyValue(Value *From, Value *To) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); - AA->copyValue(From, To); +//===----------------------------------------------------------------------===// +// Default chaining methods +//===----------------------------------------------------------------------===// + +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; } -AliasAnalysis::ModRefResult -AliasAnalysis::getModRefInfo(ImmutableCallSite CS, - const Location &Loc) { - // Don't assert AA because BasicAA calls us in order to make use of the - // logic here. +bool AAResults::pointsToConstantMemory(const MemoryLocation &Loc, + bool OrLocal) { + for (const auto &AA : AAs) + if (AA->pointsToConstantMemory(Loc, OrLocal)) + return true; - ModRefBehavior MRB = getModRefBehavior(CS); - if (MRB == DoesNotAccessMemory) - return NoModRef; + return false; +} - ModRefResult Mask = ModRef; - if (MRB == OnlyReadsMemory) - Mask = Ref; - else if (MRB == AliasAnalysis::AccessesArguments) { - bool doesAlias = false; - for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end(); - AI != AE; ++AI) - if (!isNoAlias(Location(*AI), Loc)) { - doesAlias = true; - break; - } +ModRefInfo AAResults::getArgModRefInfo(ImmutableCallSite CS, unsigned ArgIdx) { + ModRefInfo Result = MRI_ModRef; - if (!doesAlias) - return NoModRef; - } + for (const auto &AA : AAs) { + Result = ModRefInfo(Result & AA->getArgModRefInfo(CS, ArgIdx)); - // 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); + // Early-exit the moment we reach the bottom of the lattice. + if (Result == MRI_NoModRef) + return Result; + } - // If this is BasicAA, don't forward. - if (!AA) return Mask; + 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(CS, Loc) & Mask); +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; } -AliasAnalysis::ModRefResult -AliasAnalysis::getModRefInfo(ImmutableCallSite CS1, ImmutableCallSite CS2) { - // Don't assert AA because BasicAA calls us in order to make use of the - // logic here. +ModRefInfo AAResults::getModRefInfo(ImmutableCallSite CS, + const MemoryLocation &Loc) { + ModRefInfo Result = MRI_ModRef; - // If CS1 or CS2 are readnone, they don't interact. - ModRefBehavior CS1B = getModRefBehavior(CS1); - if (CS1B == DoesNotAccessMemory) return NoModRef; + for (const auto &AA : AAs) { + Result = ModRefInfo(Result & AA->getModRefInfo(CS, Loc)); - ModRefBehavior CS2B = getModRefBehavior(CS2); - if (CS2B == DoesNotAccessMemory) return NoModRef; + // Early-exit the moment we reach the bottom of the lattice. + if (Result == MRI_NoModRef) + return Result; + } - // If they both only read from memory, there is no dependence. - if (CS1B == OnlyReadsMemory && CS2B == OnlyReadsMemory) - return NoModRef; + return Result; +} - AliasAnalysis::ModRefResult Mask = ModRef; +ModRefInfo AAResults::getModRefInfo(ImmutableCallSite CS1, + ImmutableCallSite CS2) { + ModRefInfo Result = MRI_ModRef; - // If CS1 only reads memory, the only dependence on CS2 can be - // from CS1 reading memory written by CS2. - if (CS1B == OnlyReadsMemory) - Mask = ModRefResult(Mask & Ref); + for (const auto &AA : AAs) { + Result = ModRefInfo(Result & AA->getModRefInfo(CS1, CS2)); - // 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 (CS2B == AccessesArguments) { - AliasAnalysis::ModRefResult R = NoModRef; - for (ImmutableCallSite::arg_iterator - I = CS2.arg_begin(), E = CS2.arg_end(); I != E; ++I) { - R = ModRefResult((R | getModRefInfo(CS1, *I, UnknownSize)) & Mask); - if (R == Mask) - break; - } - return R; + // Early-exit the moment we reach the bottom of the lattice. + if (Result == MRI_NoModRef) + return Result; } - // 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 (CS1B == AccessesArguments) { - AliasAnalysis::ModRefResult R = NoModRef; - for (ImmutableCallSite::arg_iterator - I = CS1.arg_begin(), E = CS1.arg_end(); I != E; ++I) - if (getModRefInfo(CS2, *I, UnknownSize) != NoModRef) { - R = Mask; - break; - } - if (R == NoModRef) - return R; - } + return Result; +} - // If this is BasicAA, don't forward. - if (!AA) return Mask; +FunctionModRefBehavior AAResults::getModRefBehavior(ImmutableCallSite CS) { + FunctionModRefBehavior Result = FMRB_UnknownModRefBehavior; - // 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); -} + for (const auto &AA : AAs) { + Result = FunctionModRefBehavior(Result & AA->getModRefBehavior(CS)); -AliasAnalysis::ModRefBehavior -AliasAnalysis::getModRefBehavior(ImmutableCallSite CS) { - // Don't assert AA because BasicAA calls us in order to make use of the - // logic here. + // Early-exit the moment we reach the bottom of the lattice. + if (Result == FMRB_DoesNotAccessMemory) + return Result; + } - ModRefBehavior Min = UnknownModRefBehavior; + return Result; +} - // 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); +FunctionModRefBehavior AAResults::getModRefBehavior(const Function *F) { + FunctionModRefBehavior Result = FMRB_UnknownModRefBehavior; - // If this is BasicAA, don't forward. - if (!AA) return Min; + for (const auto &AA : AAs) { + Result = FunctionModRefBehavior(Result & AA->getModRefBehavior(F)); - // Otherwise, fall back to the next AA in the chain. But we can merge - // in any result we've managed to compute. - return std::min(AA->getModRefBehavior(CS), Min); -} + // Early-exit the moment we reach the bottom of the lattice. + if (Result == FMRB_DoesNotAccessMemory) + return Result; + } -AliasAnalysis::ModRefBehavior -AliasAnalysis::getModRefBehavior(const Function *F) { - assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!"); - return AA->getModRefBehavior(F); + return Result; } //===----------------------------------------------------------------------===// -// AliasAnalysis non-virtual helper method implementation +// Helper method implementation //===----------------------------------------------------------------------===// -AliasAnalysis::ModRefResult -AliasAnalysis::getModRefInfo(const LoadInst *L, const Location &Loc) { - // Be conservative in the face of volatile. - if (L->isVolatile()) - return ModRef; +ModRefInfo AAResults::getModRefInfo(const LoadInst *L, + const MemoryLocation &Loc) { + // Be conservative in the face of volatile/atomic. + if (!L->isUnordered()) + return MRI_ModRef; // If the load address doesn't alias the given address, it doesn't read // or write the specified memory. - if (!alias(Location(L->getOperand(0), - getTypeStoreSize(L->getType()), - L->getMetadata(LLVMContext::MD_tbaa)), - 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) { - // Be conservative in the face of volatile. - if (S->isVolatile()) - return ModRef; - - // If the store address cannot alias the pointer in question, then the - // specified memory cannot be modified by the store. - if (!alias(Location(S->getOperand(1), - getTypeStoreSize(S->getOperand(0)->getType()), - S->getMetadata(LLVMContext::MD_tbaa)), - 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; +ModRefInfo AAResults::getModRefInfo(const StoreInst *S, + const MemoryLocation &Loc) { + // Be conservative in the face of volatile/atomic. + if (!S->isUnordered()) + 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(Location(V->getOperand(0), - UnknownSize, - V->getMetadata(LLVMContext::MD_tbaa)), - Loc)) - return NoModRef; +ModRefInfo AAResults::getModRefInfo(const VAArgInst *V, + const MemoryLocation &Loc) { - // 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 (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 MRI_NoModRef; + } // Otherwise, a va_arg reads and writes. - return ModRef; + return MRI_ModRef; } -AliasAnalysis::ModRefBehavior -AliasAnalysis::getIntrinsicModRefBehavior(unsigned iid) { -#define GET_INTRINSIC_MODREF_BEHAVIOR -#include "llvm/Intrinsics.gen" -#undef GET_INTRINSIC_MODREF_BEHAVIOR +ModRefInfo AAResults::getModRefInfo(const CatchPadInst *CatchPad, + const MemoryLocation &Loc) { + if (Loc.Ptr) { + // If the pointer is a pointer to constant memory, + // then it could not have been modified by this catchpad. + if (pointsToConstantMemory(Loc)) + return MRI_NoModRef; + } + + // Otherwise, a catchpad reads and writes. + return MRI_ModRef; } -// 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() {} +ModRefInfo AAResults::getModRefInfo(const CatchReturnInst *CatchRet, + const MemoryLocation &Loc) { + if (Loc.Ptr) { + // If the pointer is a pointer to constant memory, + // then it could not have been modified by this catchpad. + if (pointsToConstantMemory(Loc)) + return MRI_NoModRef; + } -/// 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(); - AA = &P->getAnalysis(); + // Otherwise, a catchret reads and writes. + return MRI_ModRef; +} + +ModRefInfo AAResults::getModRefInfo(const AtomicCmpXchgInst *CX, + const MemoryLocation &Loc) { + // Acquire/Release cmpxchg has properties that matter for arbitrary addresses. + if (CX->getSuccessOrdering() > Monotonic) + return MRI_ModRef; + + // If the cmpxchg address does not alias the location, it does not access it. + if (Loc.Ptr && !alias(MemoryLocation::get(CX), Loc)) + return MRI_NoModRef; + + return MRI_ModRef; } -// 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 +ModRefInfo AAResults::getModRefInfo(const AtomicRMWInst *RMW, + const MemoryLocation &Loc) { + // Acquire/Release atomicrmw has properties that matter for arbitrary addresses. + if (RMW->getOrdering() > Monotonic) + return MRI_ModRef; + + // If the atomicrmw address does not alias the location, it does not access it. + if (Loc.Ptr && !alias(MemoryLocation::get(RMW), Loc)) + return MRI_NoModRef; + + return MRI_ModRef; } -/// getTypeStoreSize - Return the TargetData store size for the given type, -/// if known, or a conservative value otherwise. -/// -unsigned AliasAnalysis::getTypeStoreSize(const Type *Ty) { - return TD ? TD->getTypeStoreSize(Ty) : UnknownSize; +/// \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 MRI_ModRef; + + ImmutableCallSite CS(I); + if (!CS.getInstruction() || CS.getInstruction() == Object) + return MRI_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 + // pointer were passed to arguments that were neither of these, then it + // couldn't be no-capture. + if (!(*CI)->getType()->isPointerTy() || + (!CS.doesNotCapture(ArgNo) && !CS.isByValArgument(ArgNo))) + continue; + + // If this is a no-capture pointer argument, see if we can tell that it + // 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(MemoryLocation(*CI), MemoryLocation(Object))) + continue; + if (CS.doesNotAccessMemory(ArgNo)) + continue; + if (CS.onlyReadsMemory(ArgNo)) { + R = MRI_Ref; + continue; + } + return MRI_ModRef; + } + 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, Attribute::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; } @@ -343,8 +574,12 @@ bool llvm::isIdentifiedObject(const Value *V) { return false; } -// Because of the way .a files work, we must force the BasicAA implementation to -// be pulled in if the AliasAnalysis classes are pulled in. Otherwise we run -// the risk of AliasAnalysis being used, but the default implementation not -// being linked into the tool that uses it. -DEFINING_FILE_FOR(AliasAnalysis) +/// 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); +}