diff options
Diffstat (limited to 'lib/Transforms/ObjCARC/ObjCARCOpts.cpp')
| -rw-r--r-- | lib/Transforms/ObjCARC/ObjCARCOpts.cpp | 461 |
1 files changed, 392 insertions, 69 deletions
diff --git a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp index 9c14949877..924fb0a9da 100644 --- a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp +++ b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp @@ -33,6 +33,7 @@ #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/Statistic.h" +#include "llvm/IR/IRBuilder.h" #include "llvm/IR/LLVMContext.h" #include "llvm/Support/CFG.h" #include "llvm/Support/Debug.h" @@ -211,6 +212,9 @@ static bool DoesRetainableObjPtrEscape(const User *Ptr) { // These special functions make copies of their pointer arguments. return true; } + case IC_IntrinsicUser: + // Use by the use intrinsic is not an escape. + continue; case IC_User: case IC_None: // Use by an instruction which copies the value is an escape if the @@ -387,10 +391,6 @@ namespace { /// KnownSafe is true when either of these conditions is satisfied. bool KnownSafe; - /// True if the Calls are objc_retainBlock calls (as opposed to objc_retain - /// calls). - bool IsRetainBlock; - /// True of the objc_release calls are all marked with the "tail" keyword. bool IsTailCallRelease; @@ -407,9 +407,7 @@ namespace { SmallPtrSet<Instruction *, 2> ReverseInsertPts; RRInfo() : - KnownSafe(false), IsRetainBlock(false), - IsTailCallRelease(false), - ReleaseMetadata(0) {} + KnownSafe(false), IsTailCallRelease(false), ReleaseMetadata(0) {} void clear(); }; @@ -417,7 +415,6 @@ namespace { void RRInfo::clear() { KnownSafe = false; - IsRetainBlock = false; IsTailCallRelease = false; ReleaseMetadata = 0; Calls.clear(); @@ -451,11 +448,11 @@ namespace { KnownPositiveRefCount = true; } - void ClearRefCount() { + void ClearKnownPositiveRefCount() { KnownPositiveRefCount = false; } - bool IsKnownIncremented() const { + bool HasKnownPositiveRefCount() const { return KnownPositiveRefCount; } @@ -486,10 +483,6 @@ PtrState::Merge(const PtrState &Other, bool TopDown) { Seq = MergeSeqs(Seq, Other.Seq, TopDown); KnownPositiveRefCount = KnownPositiveRefCount && Other.KnownPositiveRefCount; - // We can't merge a plain objc_retain with an objc_retainBlock. - if (RRI.IsRetainBlock != Other.RRI.IsRetainBlock) - Seq = S_None; - // If we're not in a sequence (anymore), drop all associated state. if (Seq == S_None) { Partial = false; @@ -698,6 +691,228 @@ void BBState::MergeSucc(const BBState &Other) { MI->second.Merge(PtrState(), /*TopDown=*/false); } +// Only enable ARC Annotations if we are building a debug version of +// libObjCARCOpts. +#ifndef NDEBUG +#define ARC_ANNOTATIONS +#endif + +// Define some macros along the lines of DEBUG and some helper functions to make +// it cleaner to create annotations in the source code and to no-op when not +// building in debug mode. +#ifdef ARC_ANNOTATIONS + +#include "llvm/Support/CommandLine.h" + +/// Enable/disable ARC sequence annotations. +static cl::opt<bool> +EnableARCAnnotations("enable-objc-arc-annotations", cl::init(false)); + +/// This function appends a unique ARCAnnotationProvenanceSourceMDKind id to an +/// instruction so that we can track backwards when post processing via the llvm +/// arc annotation processor tool. If the function is an +static MDString *AppendMDNodeToSourcePtr(unsigned NodeId, + Value *Ptr) { + MDString *Hash = 0; + + // If pointer is a result of an instruction and it does not have a source + // MDNode it, attach a new MDNode onto it. If pointer is a result of + // an instruction and does have a source MDNode attached to it, return a + // reference to said Node. Otherwise just return 0. + if (Instruction *Inst = dyn_cast<Instruction>(Ptr)) { + MDNode *Node; + if (!(Node = Inst->getMetadata(NodeId))) { + // We do not have any node. Generate and attatch the hash MDString to the + // instruction. + + // We just use an MDString to ensure that this metadata gets written out + // of line at the module level and to provide a very simple format + // encoding the information herein. Both of these makes it simpler to + // parse the annotations by a simple external program. + std::string Str; + raw_string_ostream os(Str); + os << "(" << Inst->getParent()->getParent()->getName() << ",%" + << Inst->getName() << ")"; + + Hash = MDString::get(Inst->getContext(), os.str()); + Inst->setMetadata(NodeId, MDNode::get(Inst->getContext(),Hash)); + } else { + // We have a node. Grab its hash and return it. + assert(Node->getNumOperands() == 1 && + "An ARCAnnotationProvenanceSourceMDKind can only have 1 operand."); + Hash = cast<MDString>(Node->getOperand(0)); + } + } else if (Argument *Arg = dyn_cast<Argument>(Ptr)) { + std::string str; + raw_string_ostream os(str); + os << "(" << Arg->getParent()->getName() << ",%" << Arg->getName() + << ")"; + Hash = MDString::get(Arg->getContext(), os.str()); + } + + return Hash; +} + +static std::string SequenceToString(Sequence A) { + std::string str; + raw_string_ostream os(str); + os << A; + return os.str(); +} + +/// Helper function to change a Sequence into a String object using our overload +/// for raw_ostream so we only have printing code in one location. +static MDString *SequenceToMDString(LLVMContext &Context, + Sequence A) { + return MDString::get(Context, SequenceToString(A)); +} + +/// A simple function to generate a MDNode which describes the change in state +/// for Value *Ptr caused by Instruction *Inst. +static void AppendMDNodeToInstForPtr(unsigned NodeId, + Instruction *Inst, + Value *Ptr, + MDString *PtrSourceMDNodeID, + Sequence OldSeq, + Sequence NewSeq) { + MDNode *Node = 0; + Value *tmp[3] = {PtrSourceMDNodeID, + SequenceToMDString(Inst->getContext(), + OldSeq), + SequenceToMDString(Inst->getContext(), + NewSeq)}; + Node = MDNode::get(Inst->getContext(), + ArrayRef<Value*>(tmp, 3)); + + Inst->setMetadata(NodeId, Node); +} + +/// Add to the beginning of the basic block llvm.ptr.annotations which show the +/// state of a pointer at the entrance to a basic block. +static void GenerateARCBBEntranceAnnotation(const char *Name, BasicBlock *BB, + Value *Ptr, Sequence Seq) { + Module *M = BB->getParent()->getParent(); + LLVMContext &C = M->getContext(); + Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C)); + Type *I8XX = PointerType::getUnqual(I8X); + Type *Params[] = {I8XX, I8XX}; + FunctionType *FTy = FunctionType::get(Type::getVoidTy(C), + ArrayRef<Type*>(Params, 2), + /*isVarArg=*/false); + Constant *Callee = M->getOrInsertFunction(Name, FTy); + + IRBuilder<> Builder(BB, BB->getFirstInsertionPt()); + + Value *PtrName; + StringRef Tmp = Ptr->getName(); + if (0 == (PtrName = M->getGlobalVariable(Tmp, true))) { + Value *ActualPtrName = Builder.CreateGlobalStringPtr(Tmp, + Tmp + "_STR"); + PtrName = new GlobalVariable(*M, I8X, true, GlobalVariable::InternalLinkage, + cast<Constant>(ActualPtrName), Tmp); + } + + Value *S; + std::string SeqStr = SequenceToString(Seq); + if (0 == (S = M->getGlobalVariable(SeqStr, true))) { + Value *ActualPtrName = Builder.CreateGlobalStringPtr(SeqStr, + SeqStr + "_STR"); + S = new GlobalVariable(*M, I8X, true, GlobalVariable::InternalLinkage, + cast<Constant>(ActualPtrName), SeqStr); + } + + Builder.CreateCall2(Callee, PtrName, S); +} + +/// Add to the end of the basic block llvm.ptr.annotations which show the state +/// of the pointer at the bottom of the basic block. +static void GenerateARCBBTerminatorAnnotation(const char *Name, BasicBlock *BB, + Value *Ptr, Sequence Seq) { + Module *M = BB->getParent()->getParent(); + LLVMContext &C = M->getContext(); + Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C)); + Type *I8XX = PointerType::getUnqual(I8X); + Type *Params[] = {I8XX, I8XX}; + FunctionType *FTy = FunctionType::get(Type::getVoidTy(C), + ArrayRef<Type*>(Params, 2), + /*isVarArg=*/false); + Constant *Callee = M->getOrInsertFunction(Name, FTy); + + IRBuilder<> Builder(BB, llvm::prior(BB->end())); + + Value *PtrName; + StringRef Tmp = Ptr->getName(); + if (0 == (PtrName = M->getGlobalVariable(Tmp, true))) { + Value *ActualPtrName = Builder.CreateGlobalStringPtr(Tmp, + Tmp + "_STR"); + PtrName = new GlobalVariable(*M, I8X, true, GlobalVariable::InternalLinkage, + cast<Constant>(ActualPtrName), Tmp); + } + + Value *S; + std::string SeqStr = SequenceToString(Seq); + if (0 == (S = M->getGlobalVariable(SeqStr, true))) { + Value *ActualPtrName = Builder.CreateGlobalStringPtr(SeqStr, + SeqStr + "_STR"); + S = new GlobalVariable(*M, I8X, true, GlobalVariable::InternalLinkage, + cast<Constant>(ActualPtrName), SeqStr); + } + Builder.CreateCall2(Callee, PtrName, S); +} + +/// Adds a source annotation to pointer and a state change annotation to Inst +/// referencing the source annotation and the old/new state of pointer. +static void GenerateARCAnnotation(unsigned InstMDId, + unsigned PtrMDId, + Instruction *Inst, + Value *Ptr, + Sequence OldSeq, + Sequence NewSeq) { + if (EnableARCAnnotations) { + // First generate the source annotation on our pointer. This will return an + // MDString* if Ptr actually comes from an instruction implying we can put + // in a source annotation. If AppendMDNodeToSourcePtr returns 0 (i.e. NULL), + // then we know that our pointer is from an Argument so we put a reference + // to the argument number. + // + // The point of this is to make it easy for the + // llvm-arc-annotation-processor tool to cross reference where the source + // pointer is in the LLVM IR since the LLVM IR parser does not submit such + // information via debug info for backends to use (since why would anyone + // need such a thing from LLVM IR besides in non standard cases + // [i.e. this]). + MDString *SourcePtrMDNode = + AppendMDNodeToSourcePtr(PtrMDId, Ptr); + AppendMDNodeToInstForPtr(InstMDId, Inst, Ptr, SourcePtrMDNode, OldSeq, + NewSeq); + } +} + +// The actual interface for accessing the above functionality is defined via +// some simple macros which are defined below. We do this so that the user does +// not need to pass in what metadata id is needed resulting in cleaner code and +// additionally since it provides an easy way to conditionally no-op all +// annotation support in a non-debug build. + +/// Use this macro to annotate a sequence state change when processing +/// instructions bottom up, +#define ANNOTATE_BOTTOMUP(inst, ptr, old, new) \ + GenerateARCAnnotation(ARCAnnotationBottomUpMDKind, \ + ARCAnnotationProvenanceSourceMDKind, (inst), \ + const_cast<Value*>(ptr), (old), (new)) +/// Use this macro to annotate a sequence state change when processing +/// instructions top down. +#define ANNOTATE_TOPDOWN(inst, ptr, old, new) \ + GenerateARCAnnotation(ARCAnnotationTopDownMDKind, \ + ARCAnnotationProvenanceSourceMDKind, (inst), \ + const_cast<Value*>(ptr), (old), (new)) + +#else // !ARC_ANNOTATION +// If annotations are off, noop. +#define ANNOTATE_BOTTOMUP(inst, ptr, old, new) +#define ANNOTATE_TOPDOWN(inst, ptr, old, new) +#endif // !ARC_ANNOTATION + namespace { /// \brief The main ARC optimization pass. class ObjCARCOpt : public FunctionPass { @@ -738,6 +953,15 @@ namespace { /// The Metadata Kind for clang.arc.no_objc_arc_exceptions metadata. unsigned NoObjCARCExceptionsMDKind; +#ifdef ARC_ANNOTATIONS + /// The Metadata Kind for llvm.arc.annotation.bottomup metadata. + unsigned ARCAnnotationBottomUpMDKind; + /// The Metadata Kind for llvm.arc.annotation.topdown metadata. + unsigned ARCAnnotationTopDownMDKind; + /// The Metadata Kind for llvm.arc.annotation.provenancesource metadata. + unsigned ARCAnnotationProvenanceSourceMDKind; +#endif // ARC_ANNOATIONS + Constant *getRetainRVCallee(Module *M); Constant *getAutoreleaseRVCallee(Module *M); Constant *getReleaseCallee(Module *M); @@ -751,6 +975,8 @@ namespace { bool OptimizeRetainRVCall(Function &F, Instruction *RetainRV); void OptimizeAutoreleaseRVCall(Function &F, Instruction *AutoreleaseRV, InstructionClass &Class); + bool OptimizeRetainBlockCall(Function &F, Instruction *RetainBlock, + InstructionClass &Class); void OptimizeIndividualCalls(Function &F); void CheckForCFGHazards(const BasicBlock *BB, @@ -958,7 +1184,7 @@ ObjCARCOpt::OptimizeRetainCall(Function &F, Instruction *Retain) { // Check that the call is next to the retain. BasicBlock::const_iterator I = Call; ++I; - while (isNoopInstruction(I)) ++I; + while (IsNoopInstruction(I)) ++I; if (&*I != Retain) return; @@ -990,14 +1216,14 @@ ObjCARCOpt::OptimizeRetainRVCall(Function &F, Instruction *RetainRV) { if (Call->getParent() == RetainRV->getParent()) { BasicBlock::const_iterator I = Call; ++I; - while (isNoopInstruction(I)) ++I; + while (IsNoopInstruction(I)) ++I; if (&*I == RetainRV) return false; } else if (const InvokeInst *II = dyn_cast<InvokeInst>(Call)) { BasicBlock *RetainRVParent = RetainRV->getParent(); if (II->getNormalDest() == RetainRVParent) { BasicBlock::const_iterator I = RetainRVParent->begin(); - while (isNoopInstruction(I)) ++I; + while (IsNoopInstruction(I)) ++I; if (&*I == RetainRV) return false; } @@ -1008,7 +1234,7 @@ ObjCARCOpt::OptimizeRetainRVCall(Function &F, Instruction *RetainRV) { // pointer. In this case, we can delete the pair. BasicBlock::iterator I = RetainRV, Begin = RetainRV->getParent()->begin(); if (I != Begin) { - do --I; while (I != Begin && isNoopInstruction(I)); + do --I; while (I != Begin && IsNoopInstruction(I)); if (GetBasicInstructionClass(I) == IC_AutoreleaseRV && GetObjCArg(I) == Arg) { Changed = true; @@ -1084,6 +1310,35 @@ ObjCARCOpt::OptimizeAutoreleaseRVCall(Function &F, Instruction *AutoreleaseRV, } +// \brief Attempt to strength reduce objc_retainBlock calls to objc_retain +// calls. +// +// Specifically: If an objc_retainBlock call has the copy_on_escape metadata and +// does not escape (following the rules of block escaping), strength reduce the +// objc_retainBlock to an objc_retain. +// +// TODO: If an objc_retainBlock call is dominated period by a previous +// objc_retainBlock call, strength reduce the objc_retainBlock to an +// objc_retain. +bool +ObjCARCOpt::OptimizeRetainBlockCall(Function &F, Instruction *Inst, + InstructionClass &Class) { + assert(GetBasicInstructionClass(Inst) == Class); + assert(IC_RetainBlock == Class); + + // If we can not optimize Inst, return false. + if (!IsRetainBlockOptimizable(Inst)) + return false; + + CallInst *RetainBlock = cast<CallInst>(Inst); + RetainBlock->setCalledFunction(getRetainCallee(F.getParent())); + // Remove copy_on_escape metadata. + RetainBlock->setMetadata(CopyOnEscapeMDKind, 0); + Class = IC_Retain; + + return true; +} + /// Visit each call, one at a time, and make simplifications without doing any /// additional analysis. void ObjCARCOpt::OptimizeIndividualCalls(Function &F) { @@ -1125,7 +1380,7 @@ void ObjCARCOpt::OptimizeIndividualCalls(Function &F) { case IC_InitWeak: case IC_DestroyWeak: { CallInst *CI = cast<CallInst>(Inst); - if (isNullOrUndef(CI->getArgOperand(0))) { + if (IsNullOrUndef(CI->getArgOperand(0))) { Changed = true; Type *Ty = CI->getArgOperand(0)->getType(); new StoreInst(UndefValue::get(cast<PointerType>(Ty)->getElementType()), @@ -1146,8 +1401,8 @@ void ObjCARCOpt::OptimizeIndividualCalls(Function &F) { case IC_CopyWeak: case IC_MoveWeak: { CallInst *CI = cast<CallInst>(Inst); - if (isNullOrUndef(CI->getArgOperand(0)) || - isNullOrUndef(CI->getArgOperand(1))) { + if (IsNullOrUndef(CI->getArgOperand(0)) || + IsNullOrUndef(CI->getArgOperand(1))) { Changed = true; Type *Ty = CI->getArgOperand(0)->getType(); new StoreInst(UndefValue::get(cast<PointerType>(Ty)->getElementType()), @@ -1167,6 +1422,12 @@ void ObjCARCOpt::OptimizeIndividualCalls(Function &F) { } break; } + case IC_RetainBlock: + // If we strength reduce an objc_retainBlock to amn objc_retain, continue + // onto the objc_retain peephole optimizations. Otherwise break. + if (!OptimizeRetainBlockCall(F, Inst, Class)) + break; + // FALLTHROUGH case IC_Retain: OptimizeRetainCall(F, Inst); break; @@ -1245,7 +1506,7 @@ void ObjCARCOpt::OptimizeIndividualCalls(Function &F) { const Value *Arg = GetObjCArg(Inst); // ARC calls with null are no-ops. Delete them. - if (isNullOrUndef(Arg)) { + if (IsNullOrUndef(Arg)) { Changed = true; ++NumNoops; DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: ARC calls with " @@ -1280,7 +1541,7 @@ void ObjCARCOpt::OptimizeIndividualCalls(Function &F) { for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { Value *Incoming = StripPointerCastsAndObjCCalls(PN->getIncomingValue(i)); - if (isNullOrUndef(Incoming)) + if (IsNullOrUndef(Incoming)) HasNull = true; else if (cast<TerminatorInst>(PN->getIncomingBlock(i)->back()) .getNumSuccessors() != 1) { @@ -1334,7 +1595,7 @@ void ObjCARCOpt::OptimizeIndividualCalls(Function &F) { for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { Value *Incoming = StripPointerCastsAndObjCCalls(PN->getIncomingValue(i)); - if (!isNullOrUndef(Incoming)) { + if (!IsNullOrUndef(Incoming)) { CallInst *Clone = cast<CallInst>(CInst->clone()); Value *Op = PN->getIncomingValue(i); Instruction *InsertPos = &PN->getIncomingBlock(i)->back(); @@ -1502,21 +1763,21 @@ ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst, } MDNode *ReleaseMetadata = Inst->getMetadata(ImpreciseReleaseMDKind); - S.ResetSequenceProgress(ReleaseMetadata ? S_MovableRelease : S_Release); + Sequence NewSeq = ReleaseMetadata ? S_MovableRelease : S_Release; + ANNOTATE_BOTTOMUP(Inst, Arg, S.GetSeq(), NewSeq); + S.ResetSequenceProgress(NewSeq); S.RRI.ReleaseMetadata = ReleaseMetadata; - S.RRI.KnownSafe = S.IsKnownIncremented(); + S.RRI.KnownSafe = S.HasKnownPositiveRefCount(); S.RRI.IsTailCallRelease = cast<CallInst>(Inst)->isTailCall(); S.RRI.Calls.insert(Inst); - S.SetKnownPositiveRefCount(); break; } case IC_RetainBlock: - // An objc_retainBlock call with just a use may need to be kept, - // because it may be copying a block from the stack to the heap. - if (!IsRetainBlockOptimizable(Inst)) - break; - // FALLTHROUGH + // In OptimizeIndividualCalls, we have strength reduced all optimizable + // objc_retainBlocks to objc_retains. Thus at this point any + // objc_retainBlocks that we see are not optimizable. + break; case IC_Retain: case IC_RetainRV: { Arg = GetObjCArg(Inst); @@ -1524,7 +1785,8 @@ ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst, PtrState &S = MyStates.getPtrBottomUpState(Arg); S.SetKnownPositiveRefCount(); - switch (S.GetSeq()) { + Sequence OldSeq = S.GetSeq(); + switch (OldSeq) { case S_Stop: case S_Release: case S_MovableRelease: @@ -1534,10 +1796,8 @@ ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst, case S_CanRelease: // Don't do retain+release tracking for IC_RetainRV, because it's // better to let it remain as the first instruction after a call. - if (Class != IC_RetainRV) { - S.RRI.IsRetainBlock = Class == IC_RetainBlock; + if (Class != IC_RetainRV) Retains[Inst] = S.RRI; - } S.ClearSequenceProgress(); break; case S_None: @@ -1545,6 +1805,7 @@ ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst, case S_Retain: llvm_unreachable("bottom-up pointer in retain state!"); } + ANNOTATE_BOTTOMUP(Inst, Arg, OldSeq, S.GetSeq()); return NestingDetected; } case IC_AutoreleasepoolPop: @@ -1571,10 +1832,11 @@ ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst, // Check for possible releases. if (CanAlterRefCount(Inst, Ptr, PA, Class)) { - S.ClearRefCount(); + S.ClearKnownPositiveRefCount(); switch (Seq) { case S_Use: S.SetSeq(S_CanRelease); + ANNOTATE_BOTTOMUP(Inst, Ptr, Seq, S.GetSeq()); continue; case S_CanRelease: case S_Release: @@ -1601,10 +1863,11 @@ ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst, else S.RRI.ReverseInsertPts.insert(llvm::next(BasicBlock::iterator(Inst))); S.SetSeq(S_Use); - } else if (Seq == S_Release && - (Class == IC_User || Class == IC_CallOrUser)) { + ANNOTATE_BOTTOMUP(Inst, Ptr, Seq, S_Use); + } else if (Seq == S_Release && IsUser(Class)) { // Non-movable releases depend on any possible objc pointer use. S.SetSeq(S_Stop); + ANNOTATE_BOTTOMUP(Inst, Ptr, S_Release, S_Stop); assert(S.RRI.ReverseInsertPts.empty()); // As above; handle invoke specially. if (isa<InvokeInst>(Inst)) @@ -1614,8 +1877,10 @@ ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst, } break; case S_Stop: - if (CanUse(Inst, Ptr, PA, Class)) + if (CanUse(Inst, Ptr, PA, Class)) { S.SetSeq(S_Use); + ANNOTATE_BOTTOMUP(Inst, Ptr, Seq, S_Use); + } break; case S_CanRelease: case S_Use: @@ -1654,6 +1919,21 @@ ObjCARCOpt::VisitBottomUp(BasicBlock *BB, } } +#ifdef ARC_ANNOTATIONS + if (EnableARCAnnotations) { + // If ARC Annotations are enabled, output the current state of pointers at the + // bottom of the basic block. + for(BBState::ptr_const_iterator I = MyStates.bottom_up_ptr_begin(), + E = MyStates.bottom_up_ptr_end(); I != E; ++I) { + Value *Ptr = const_cast<Value*>(I->first); + Sequence Seq = I->second.GetSeq(); + GenerateARCBBTerminatorAnnotation("llvm.arc.annotation.bottomup.bbend", + BB, Ptr, Seq); + } + } +#endif + + // Visit all the instructions, bottom-up. for (BasicBlock::iterator I = BB->end(), E = BB->begin(); I != E; --I) { Instruction *Inst = llvm::prior(I); @@ -1677,6 +1957,20 @@ ObjCARCOpt::VisitBottomUp(BasicBlock *BB, NestingDetected |= VisitInstructionBottomUp(II, BB, Retains, MyStates); } +#ifdef ARC_ANNOTATIONS + if (EnableARCAnnotations) { + // If ARC Annotations are enabled, output the current state of pointers at the + // top of the basic block. + for(BBState::ptr_const_iterator I = MyStates.bottom_up_ptr_begin(), + E = MyStates.bottom_up_ptr_end(); I != E; ++I) { + Value *Ptr = const_cast<Value*>(I->first); + Sequence Seq = I->second.GetSeq(); + GenerateARCBBEntranceAnnotation("llvm.arc.annotation.bottomup.bbstart", + BB, Ptr, Seq); + } + } +#endif + return NestingDetected; } @@ -1690,11 +1984,10 @@ ObjCARCOpt::VisitInstructionTopDown(Instruction *Inst, switch (Class) { case IC_RetainBlock: - // An objc_retainBlock call with just a use may need to be kept, - // because it may be copying a block from the stack to the heap. - if (!IsRetainBlockOptimizable(Inst)) - break; - // FALLTHROUGH + // In OptimizeIndividualCalls, we have strength reduced all optimizable + // objc_retainBlocks to objc_retains. Thus at this point any + // objc_retainBlocks that we see are not optimizable. + break; case IC_Retain: case IC_RetainRV: { Arg = GetObjCArg(Inst); @@ -1714,9 +2007,9 @@ ObjCARCOpt::VisitInstructionTopDown(Instruction *Inst, if (S.GetSeq() == S_Retain) NestingDetected = true; + ANNOTATE_TOPDOWN(Inst, Arg, S.GetSeq(), S_Retain); S.ResetSequenceProgress(S_Retain); - S.RRI.IsRetainBlock = Class == IC_RetainBlock; - S.RRI.KnownSafe = S.IsKnownIncremented(); + S.RRI.KnownSafe = S.HasKnownPositiveRefCount(); S.RRI.Calls.insert(Inst); } @@ -1730,7 +2023,7 @@ ObjCARCOpt::VisitInstructionTopDown(Instruction *Inst, Arg = GetObjCArg(Inst); PtrState &S = MyStates.getPtrTopDownState(Arg); - S.ClearRefCount(); + S.ClearKnownPositiveRefCount(); switch (S.GetSeq()) { case S_Retain: @@ -1741,6 +2034,7 @@ ObjCARCOpt::VisitInstructionTopDown(Instruction *Inst, S.RRI.ReleaseMetadata = Inst->getMetadata(ImpreciseReleaseMDKind); S.RRI.IsTailCallRelease = cast<CallInst>(Inst)->isTailCall(); Releases[Inst] = S.RRI; + ANNOTATE_TOPDOWN(Inst, Arg, S.GetSeq(), S_None); S.ClearSequenceProgress(); break; case S_None: @@ -1776,10 +2070,11 @@ ObjCARCOpt::VisitInstructionTopDown(Instruction *Inst, // Check for possible releases. if (CanAlterRefCount(Inst, Ptr, PA, Class)) { - S.ClearRefCount(); + S.ClearKnownPositiveRefCount(); switch (Seq) { case S_Retain: S.SetSeq(S_CanRelease); + ANNOTATE_TOPDOWN(Inst, Ptr, Seq, S_CanRelease); assert(S.RRI.ReverseInsertPts.empty()); S.RRI.ReverseInsertPts.insert(Inst); @@ -1801,8 +2096,10 @@ ObjCARCOpt::VisitInstructionTopDown(Instruction *Inst, // Check for possible direct uses. switch (Seq) { case S_CanRelease: - if (CanUse(Inst, Ptr, PA, Class)) + if (CanUse(Inst, Ptr, PA, Class)) { S.SetSeq(S_Use); + ANNOTATE_TOPDOWN(Inst, Ptr, Seq, S_Use); + } break; case S_Retain: case S_Use: @@ -1843,6 +2140,20 @@ ObjCARCOpt::VisitTopDown(BasicBlock *BB, } } +#ifdef ARC_ANNOTATIONS + if (EnableARCAnnotations) { + // If ARC Annotations are enabled, output the current state of pointers at the + // top of the basic block. + for(BBState::ptr_const_iterator I = MyStates.top_down_ptr_begin(), + E = MyStates.top_down_ptr_end(); I != E; ++I) { + Value *Ptr = const_cast<Value*>(I->first); + Sequence Seq = I->second.GetSeq(); + GenerateARCBBEntranceAnnotation("llvm.arc.annotation.topdown.bbstart", + BB, Ptr, Seq); + } + } +#endif + // Visit all the instructions, top-down. for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { Instruction *Inst = I; @@ -1852,6 +2163,20 @@ ObjCARCOpt::VisitTopDown(BasicBlock *BB, NestingDetected |= VisitInstructionTopDown(Inst, Releases, MyStates); } +#ifdef ARC_ANNOTATIONS + if (EnableARCAnnotations) { + // If ARC Annotations are enabled, output the current state of pointers at the + // bottom of the basic block. + for(BBState::ptr_const_iterator I = MyStates.top_down_ptr_begin(), + E = MyStates.top_down_ptr_end(); I != E; ++I) { + Value *Ptr = const_cast<Value*>(I->first); + Sequence Seq = I->second.GetSeq(); + GenerateARCBBTerminatorAnnotation("llvm.arc.annotation.topdown.bbend", + BB, Ptr, Seq); + } + } +#endif + CheckForCFGHazards(BB, BBStates, MyStates); return NestingDetected; } @@ -1991,15 +2316,9 @@ void ObjCARCOpt::MoveCalls(Value *Arg, Value *MyArg = ArgTy == ParamTy ? Arg : new BitCastInst(Arg, ParamTy, "", InsertPt); CallInst *Call = - CallInst::Create(RetainsToMove.IsRetainBlock ? - getRetainBlockCallee(M) : getRetainCallee(M), - MyArg, "", InsertPt); + CallInst::Create(getRetainCallee(M), MyArg, "", InsertPt); Call->setDoesNotThrow(); - if (RetainsToMove.IsRetainBlock) - Call->setMetadata(CopyOnEscapeMDKind, - MDNode::get(M->getContext(), ArrayRef<Value *>())); - else - Call->setTailCall(); + Call->setTailCall(); DEBUG(dbgs() << "ObjCARCOpt::MoveCalls: Inserting new Release: " << *Call << "\n" @@ -2075,7 +2394,6 @@ ObjCARCOpt::ConnectTDBUTraversals(DenseMap<const BasicBlock *, BBState> unsigned OldCount = 0; unsigned NewCount = 0; bool FirstRelease = true; - bool FirstRetain = true; for (;;) { for (SmallVectorImpl<Instruction *>::const_iterator NI = NewRetains.begin(), NE = NewRetains.end(); NI != NE; ++NI) { @@ -2156,16 +2474,6 @@ ObjCARCOpt::ConnectTDBUTraversals(DenseMap<const BasicBlock *, BBState> OldDelta += PathCount; OldCount += PathCount; - // Merge the IsRetainBlock values. - if (FirstRetain) { - RetainsToMove.IsRetainBlock = NewReleaseRetainRRI.IsRetainBlock; - FirstRetain = false; - } else if (ReleasesToMove.IsRetainBlock != - NewReleaseRetainRRI.IsRetainBlock) - // It's not possible to merge the sequences if one uses - // objc_retain and the other uses objc_retainBlock. - return false; - // Collect the optimal insertion points. if (!KnownSafe) for (SmallPtrSet<Instruction *, 2>::const_iterator @@ -2271,6 +2579,12 @@ ObjCARCOpt::PerformCodePlacement(DenseMap<const BasicBlock *, BBState> ReleasesToMove, Arg, KnownSafe, AnyPairsCompletelyEliminated); +#ifdef ARC_ANNOTATIONS + // Do not move calls if ARC annotations are requested. If we were to move + // calls in this case, we would not be able + PerformMoveCalls = PerformMoveCalls && !EnableARCAnnotations; +#endif // ARC_ANNOTATIONS + if (PerformMoveCalls) { // Ok, everything checks out and we're all set. Let's move/delete some // code! @@ -2392,6 +2706,7 @@ void ObjCARCOpt::OptimizeWeakCalls(Function &F) { goto clobbered; case IC_AutoreleasepoolPush: case IC_None: + case IC_IntrinsicUser: case IC_User: // Weak pointers are only modified through the weak entry points // (and arbitrary calls, which could call the weak entry points). @@ -2617,6 +2932,14 @@ bool ObjCARCOpt::doInitialization(Module &M) { M.getContext().getMDKindID("clang.arc.copy_on_escape"); NoObjCARCExceptionsMDKind = M.getContext().getMDKindID("clang.arc.no_objc_arc_exceptions"); +#ifdef ARC_ANNOTATIONS + ARCAnnotationBottomUpMDKind = + M.getContext().getMDKindID("llvm.arc.annotation.bottomup"); + ARCAnnotationTopDownMDKind = + M.getContext().getMDKindID("llvm.arc.annotation.topdown"); + ARCAnnotationProvenanceSourceMDKind = + M.getContext().getMDKindID("llvm.arc.annotation.provenancesource"); +#endif // ARC_ANNOTATIONS // Intuitively, objc_retain and others are nocapture, however in practice // they are not, because they return their argument value. And objc_release |