diff options
| -rw-r--r-- | lib/Transforms/ObjCARC/ObjCARCOpts.cpp | 191 |
1 files changed, 186 insertions, 5 deletions
diff --git a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp index 27bc2bb..d13baf3 100644 --- a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp +++ b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp @@ -701,6 +701,151 @@ 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; +} + +/// 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) { + std::string str; + raw_string_ostream os(str); + os << A; + return MDString::get(Context, os.str()); +} + +/// 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); +} + +/// 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 { @@ -741,6 +886,15 @@ 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); @@ -1505,12 +1659,13 @@ 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.HasKnownPositiveRefCount(); S.RRI.IsTailCallRelease = cast<CallInst>(Inst)->isTailCall(); S.RRI.Calls.insert(Inst); - S.SetKnownPositiveRefCount(); break; } @@ -1527,7 +1682,8 @@ 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: @@ -1548,6 +1704,7 @@ 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: @@ -1578,6 +1735,7 @@ ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst, switch (Seq) { case S_Use: S.SetSeq(S_CanRelease); + ANNOTATE_BOTTOMUP(Inst, Ptr, Seq, S.GetSeq()); continue; case S_CanRelease: case S_Release: @@ -1604,9 +1762,11 @@ ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst, else S.RRI.ReverseInsertPts.insert(llvm::next(BasicBlock::iterator(Inst))); S.SetSeq(S_Use); + 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)) @@ -1616,8 +1776,10 @@ 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: @@ -1716,6 +1878,7 @@ 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.HasKnownPositiveRefCount(); @@ -1743,6 +1906,7 @@ 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: @@ -1782,6 +1946,7 @@ ObjCARCOpt::VisitInstructionTopDown(Instruction *Inst, 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); @@ -1803,8 +1968,10 @@ 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: @@ -2273,6 +2440,12 @@ 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! @@ -2620,6 +2793,14 @@ 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 |