///
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "objc-arc-opts"
#include "ObjCARC.h"
+#include "ARCRuntimeEntryPoints.h"
#include "DependencyAnalysis.h"
#include "ObjCARCAliasAnalysis.h"
#include "ProvenanceAnalysis.h"
+#include "BlotMapVector.h"
+#include "PtrState.h"
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/IR/CFG.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/LLVMContext.h"
-#include "llvm/Support/CFG.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
using namespace llvm::objcarc;
-/// \defgroup MiscUtils Miscellaneous utilities that are not ARC specific.
-/// @{
-
-namespace {
- /// \brief An associative container with fast insertion-order (deterministic)
- /// iteration over its elements. Plus the special blot operation.
- template<class KeyT, class ValueT>
- class MapVector {
- /// Map keys to indices in Vector.
- typedef DenseMap<KeyT, size_t> MapTy;
- MapTy Map;
-
- typedef std::vector<std::pair<KeyT, ValueT> > VectorTy;
- /// Keys and values.
- VectorTy Vector;
-
- public:
- typedef typename VectorTy::iterator iterator;
- typedef typename VectorTy::const_iterator const_iterator;
- iterator begin() { return Vector.begin(); }
- iterator end() { return Vector.end(); }
- const_iterator begin() const { return Vector.begin(); }
- const_iterator end() const { return Vector.end(); }
-
-#ifdef XDEBUG
- ~MapVector() {
- assert(Vector.size() >= Map.size()); // May differ due to blotting.
- for (typename MapTy::const_iterator I = Map.begin(), E = Map.end();
- I != E; ++I) {
- assert(I->second < Vector.size());
- assert(Vector[I->second].first == I->first);
- }
- for (typename VectorTy::const_iterator I = Vector.begin(),
- E = Vector.end(); I != E; ++I)
- assert(!I->first ||
- (Map.count(I->first) &&
- Map[I->first] == size_t(I - Vector.begin())));
- }
-#endif
-
- ValueT &operator[](const KeyT &Arg) {
- std::pair<typename MapTy::iterator, bool> Pair =
- Map.insert(std::make_pair(Arg, size_t(0)));
- if (Pair.second) {
- size_t Num = Vector.size();
- Pair.first->second = Num;
- Vector.push_back(std::make_pair(Arg, ValueT()));
- return Vector[Num].second;
- }
- return Vector[Pair.first->second].second;
- }
-
- std::pair<iterator, bool>
- insert(const std::pair<KeyT, ValueT> &InsertPair) {
- std::pair<typename MapTy::iterator, bool> Pair =
- Map.insert(std::make_pair(InsertPair.first, size_t(0)));
- if (Pair.second) {
- size_t Num = Vector.size();
- Pair.first->second = Num;
- Vector.push_back(InsertPair);
- return std::make_pair(Vector.begin() + Num, true);
- }
- return std::make_pair(Vector.begin() + Pair.first->second, false);
- }
-
- const_iterator find(const KeyT &Key) const {
- typename MapTy::const_iterator It = Map.find(Key);
- if (It == Map.end()) return Vector.end();
- return Vector.begin() + It->second;
- }
-
- /// This is similar to erase, but instead of removing the element from the
- /// vector, it just zeros out the key in the vector. This leaves iterators
- /// intact, but clients must be prepared for zeroed-out keys when iterating.
- void blot(const KeyT &Key) {
- typename MapTy::iterator It = Map.find(Key);
- if (It == Map.end()) return;
- Vector[It->second].first = KeyT();
- Map.erase(It);
- }
-
- void clear() {
- Map.clear();
- Vector.clear();
- }
- };
-}
+#define DEBUG_TYPE "objc-arc-opts"
-/// @}
-///
/// \defgroup ARCUtilities Utility declarations/definitions specific to ARC.
/// @{
-/// \brief This is similar to StripPointerCastsAndObjCCalls but it stops as soon
+/// \brief This is similar to GetRCIdentityRoot but it stops as soon
/// as it finds a value with multiple uses.
static const Value *FindSingleUseIdentifiedObject(const Value *Arg) {
if (Arg->hasOneUse()) {
if (const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Arg))
if (GEP->hasAllZeroIndices())
return FindSingleUseIdentifiedObject(GEP->getPointerOperand());
- if (IsForwarding(GetBasicInstructionClass(Arg)))
+ if (IsForwarding(GetBasicARCInstKind(Arg)))
return FindSingleUseIdentifiedObject(
cast<CallInst>(Arg)->getArgOperand(0));
if (!IsObjCIdentifiedObject(Arg))
- return 0;
+ return nullptr;
return Arg;
}
// If we found an identifiable object but it has multiple uses, but they are
// trivial uses, we can still consider this to be a single-use value.
if (IsObjCIdentifiedObject(Arg)) {
- for (Value::const_use_iterator UI = Arg->use_begin(), UE = Arg->use_end();
- UI != UE; ++UI) {
- const User *U = *UI;
- if (!U->use_empty() || StripPointerCastsAndObjCCalls(U) != Arg)
- return 0;
- }
+ for (const User *U : Arg->users())
+ if (!U->use_empty() || GetRCIdentityRoot(U) != Arg)
+ return nullptr;
return Arg;
}
- return 0;
+ return nullptr;
}
-/// \brief Test whether the given retainable object pointer escapes.
-///
-/// This differs from regular escape analysis in that a use as an
-/// argument to a call is not considered an escape.
-///
-static bool DoesRetainableObjPtrEscape(const User *Ptr) {
- DEBUG(dbgs() << "DoesRetainableObjPtrEscape: Target: " << *Ptr << "\n");
-
- // Walk the def-use chains.
+/// This is a wrapper around getUnderlyingObjCPtr along the lines of
+/// GetUnderlyingObjects except that it returns early when it sees the first
+/// alloca.
+static inline bool AreAnyUnderlyingObjectsAnAlloca(const Value *V) {
+ SmallPtrSet<const Value *, 4> Visited;
SmallVector<const Value *, 4> Worklist;
- Worklist.push_back(Ptr);
- // If Ptr has any operands add them as well.
- for (User::const_op_iterator I = Ptr->op_begin(), E = Ptr->op_end(); I != E;
- ++I) {
- Worklist.push_back(*I);
- }
-
- // Ensure we do not visit any value twice.
- SmallPtrSet<const Value *, 8> VisitedSet;
-
+ Worklist.push_back(V);
do {
- const Value *V = Worklist.pop_back_val();
-
- DEBUG(dbgs() << "DoesRetainableObjPtrEscape: Visiting: " << *V << "\n");
-
- for (Value::const_use_iterator UI = V->use_begin(), UE = V->use_end();
- UI != UE; ++UI) {
- const User *UUser = *UI;
-
- DEBUG(dbgs() << "DoesRetainableObjPtrEscape: User: " << *UUser << "\n");
-
- // Special - Use by a call (callee or argument) is not considered
- // to be an escape.
- switch (GetBasicInstructionClass(UUser)) {
- case IC_StoreWeak:
- case IC_InitWeak:
- case IC_StoreStrong:
- case IC_Autorelease:
- case IC_AutoreleaseRV: {
- DEBUG(dbgs() << "DoesRetainableObjPtrEscape: User copies pointer "
- "arguments. Pointer Escapes!\n");
- // 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
- // result is an escape.
- if (isa<BitCastInst>(UUser) || isa<GetElementPtrInst>(UUser) ||
- isa<PHINode>(UUser) || isa<SelectInst>(UUser)) {
-
- if (VisitedSet.insert(UUser)) {
- DEBUG(dbgs() << "DoesRetainableObjPtrEscape: User copies value. "
- "Ptr escapes if result escapes. Adding to list.\n");
- Worklist.push_back(UUser);
- } else {
- DEBUG(dbgs() << "DoesRetainableObjPtrEscape: Already visited node."
- "\n");
- }
- continue;
- }
- // Use by a load is not an escape.
- if (isa<LoadInst>(UUser))
- continue;
- // Use by a store is not an escape if the use is the address.
- if (const StoreInst *SI = dyn_cast<StoreInst>(UUser))
- if (V != SI->getValueOperand())
- continue;
- break;
- default:
- // Regular calls and other stuff are not considered escapes.
- continue;
- }
- // Otherwise, conservatively assume an escape.
- DEBUG(dbgs() << "DoesRetainableObjPtrEscape: Assuming ptr escapes.\n");
+ const Value *P = Worklist.pop_back_val();
+ P = GetUnderlyingObjCPtr(P);
+
+ if (isa<AllocaInst>(P))
return true;
+
+ if (!Visited.insert(P).second)
+ continue;
+
+ if (const SelectInst *SI = dyn_cast<const SelectInst>(P)) {
+ Worklist.push_back(SI->getTrueValue());
+ Worklist.push_back(SI->getFalseValue());
+ continue;
+ }
+
+ if (const PHINode *PN = dyn_cast<const PHINode>(P)) {
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+ Worklist.push_back(PN->getIncomingValue(i));
+ continue;
}
} while (!Worklist.empty());
- // No escapes found.
- DEBUG(dbgs() << "DoesRetainableObjPtrEscape: Ptr does not escape.\n");
return false;
}
+
/// @}
///
/// \defgroup ARCOpt ARC Optimization.
STATISTIC(NumPartialNoops, "Number of partially no-op objc calls eliminated");
STATISTIC(NumAutoreleases,"Number of autoreleases converted to releases");
STATISTIC(NumRets, "Number of return value forwarding "
- "retain+autoreleaes eliminated");
+ "retain+autoreleases eliminated");
STATISTIC(NumRRs, "Number of retain+release paths eliminated");
STATISTIC(NumPeeps, "Number of calls peephole-optimized");
-
-namespace {
- /// \enum Sequence
- ///
- /// \brief A sequence of states that a pointer may go through in which an
- /// objc_retain and objc_release are actually needed.
- enum Sequence {
- S_None,
- S_Retain, ///< objc_retain(x).
- S_CanRelease, ///< foo(x) -- x could possibly see a ref count decrement.
- S_Use, ///< any use of x.
- S_Stop, ///< like S_Release, but code motion is stopped.
- S_Release, ///< objc_release(x).
- S_MovableRelease ///< objc_release(x), !clang.imprecise_release.
- };
-
- raw_ostream &operator<<(raw_ostream &OS, const Sequence S)
- LLVM_ATTRIBUTE_UNUSED;
- raw_ostream &operator<<(raw_ostream &OS, const Sequence S) {
- switch (S) {
- case S_None:
- return OS << "S_None";
- case S_Retain:
- return OS << "S_Retain";
- case S_CanRelease:
- return OS << "S_CanRelease";
- case S_Use:
- return OS << "S_Use";
- case S_Release:
- return OS << "S_Release";
- case S_MovableRelease:
- return OS << "S_MovableRelease";
- case S_Stop:
- return OS << "S_Stop";
- }
- llvm_unreachable("Unknown sequence type.");
- }
-}
-
-static Sequence MergeSeqs(Sequence A, Sequence B, bool TopDown) {
- // The easy cases.
- if (A == B)
- return A;
- if (A == S_None || B == S_None)
- return S_None;
-
- if (A > B) std::swap(A, B);
- if (TopDown) {
- // Choose the side which is further along in the sequence.
- if ((A == S_Retain || A == S_CanRelease) &&
- (B == S_CanRelease || B == S_Use))
- return B;
- } else {
- // Choose the side which is further along in the sequence.
- if ((A == S_Use || A == S_CanRelease) &&
- (B == S_Use || B == S_Release || B == S_Stop || B == S_MovableRelease))
- return A;
- // If both sides are releases, choose the more conservative one.
- if (A == S_Stop && (B == S_Release || B == S_MovableRelease))
- return A;
- if (A == S_Release && B == S_MovableRelease)
- return A;
- }
-
- return S_None;
-}
-
-namespace {
- /// \brief Unidirectional information about either a
- /// retain-decrement-use-release sequence or release-use-decrement-retain
- /// reverese sequence.
- struct RRInfo {
- /// After an objc_retain, the reference count of the referenced
- /// object is known to be positive. Similarly, before an objc_release, the
- /// reference count of the referenced object is known to be positive. If
- /// there are retain-release pairs in code regions where the retain count
- /// is known to be positive, they can be eliminated, regardless of any side
- /// effects between them.
- ///
- /// Also, a retain+release pair nested within another retain+release
- /// pair all on the known same pointer value can be eliminated, regardless
- /// of any intervening side effects.
- ///
- /// KnownSafe is true when either of these conditions is satisfied.
- bool KnownSafe;
-
- /// True of the objc_release calls are all marked with the "tail" keyword.
- bool IsTailCallRelease;
-
- /// If the Calls are objc_release calls and they all have a
- /// clang.imprecise_release tag, this is the metadata tag.
- MDNode *ReleaseMetadata;
-
- /// For a top-down sequence, the set of objc_retains or
- /// objc_retainBlocks. For bottom-up, the set of objc_releases.
- SmallPtrSet<Instruction *, 2> Calls;
-
- /// The set of optimal insert positions for moving calls in the opposite
- /// sequence.
- SmallPtrSet<Instruction *, 2> ReverseInsertPts;
-
- RRInfo() :
- KnownSafe(false), IsTailCallRelease(false), ReleaseMetadata(0) {}
-
- void clear();
- };
-}
-
-void RRInfo::clear() {
- KnownSafe = false;
- IsTailCallRelease = false;
- ReleaseMetadata = 0;
- Calls.clear();
- ReverseInsertPts.clear();
-}
-
-namespace {
- /// \brief This class summarizes several per-pointer runtime properties which
- /// are propogated through the flow graph.
- class PtrState {
- /// True if the reference count is known to be incremented.
- bool KnownPositiveRefCount;
-
- /// True of we've seen an opportunity for partial RR elimination, such as
- /// pushing calls into a CFG triangle or into one side of a CFG diamond.
- bool Partial;
-
- /// The current position in the sequence.
- Sequence Seq : 8;
-
- public:
- /// Unidirectional information about the current sequence.
- ///
- /// TODO: Encapsulate this better.
- RRInfo RRI;
-
- PtrState() : KnownPositiveRefCount(false), Partial(false),
- Seq(S_None) {}
-
- void SetKnownPositiveRefCount() {
- KnownPositiveRefCount = true;
- }
-
- void ClearKnownPositiveRefCount() {
- KnownPositiveRefCount = false;
- }
-
- bool HasKnownPositiveRefCount() const {
- return KnownPositiveRefCount;
- }
-
- void SetSeq(Sequence NewSeq) {
- Seq = NewSeq;
- }
-
- Sequence GetSeq() const {
- return Seq;
- }
-
- void ClearSequenceProgress() {
- ResetSequenceProgress(S_None);
- }
-
- void ResetSequenceProgress(Sequence NewSeq) {
- Seq = NewSeq;
- Partial = false;
- RRI.clear();
- }
-
- void Merge(const PtrState &Other, bool TopDown);
- };
-}
-
-void
-PtrState::Merge(const PtrState &Other, bool TopDown) {
- Seq = MergeSeqs(Seq, Other.Seq, TopDown);
- KnownPositiveRefCount = KnownPositiveRefCount && Other.KnownPositiveRefCount;
-
- // If we're not in a sequence (anymore), drop all associated state.
- if (Seq == S_None) {
- Partial = false;
- RRI.clear();
- } else if (Partial || Other.Partial) {
- // If we're doing a merge on a path that's previously seen a partial
- // merge, conservatively drop the sequence, to avoid doing partial
- // RR elimination. If the branch predicates for the two merge differ,
- // mixing them is unsafe.
- ClearSequenceProgress();
- } else {
- // Conservatively merge the ReleaseMetadata information.
- if (RRI.ReleaseMetadata != Other.RRI.ReleaseMetadata)
- RRI.ReleaseMetadata = 0;
-
- RRI.KnownSafe = RRI.KnownSafe && Other.RRI.KnownSafe;
- RRI.IsTailCallRelease = RRI.IsTailCallRelease &&
- Other.RRI.IsTailCallRelease;
- RRI.Calls.insert(Other.RRI.Calls.begin(), Other.RRI.Calls.end());
-
- // Merge the insert point sets. If there are any differences,
- // that makes this a partial merge.
- Partial = RRI.ReverseInsertPts.size() != Other.RRI.ReverseInsertPts.size();
- for (SmallPtrSet<Instruction *, 2>::const_iterator
- I = Other.RRI.ReverseInsertPts.begin(),
- E = Other.RRI.ReverseInsertPts.end(); I != E; ++I)
- Partial |= RRI.ReverseInsertPts.insert(*I);
- }
-}
+#ifndef NDEBUG
+STATISTIC(NumRetainsBeforeOpt,
+ "Number of retains before optimization");
+STATISTIC(NumReleasesBeforeOpt,
+ "Number of releases before optimization");
+STATISTIC(NumRetainsAfterOpt,
+ "Number of retains after optimization");
+STATISTIC(NumReleasesAfterOpt,
+ "Number of releases after optimization");
+#endif
namespace {
/// \brief Per-BasicBlock state.
/// The number of unique control paths to exits from this block.
unsigned BottomUpPathCount;
- /// A type for PerPtrTopDown and PerPtrBottomUp.
- typedef MapVector<const Value *, PtrState> MapTy;
-
/// The top-down traversal uses this to record information known about a
/// pointer at the bottom of each block.
- MapTy PerPtrTopDown;
+ BlotMapVector<const Value *, TopDownPtrState> PerPtrTopDown;
/// The bottom-up traversal uses this to record information known about a
/// pointer at the top of each block.
- MapTy PerPtrBottomUp;
+ BlotMapVector<const Value *, BottomUpPtrState> PerPtrBottomUp;
/// Effective predecessors of the current block ignoring ignorable edges and
/// ignored backedges.
SmallVector<BasicBlock *, 2> Preds;
+
/// Effective successors of the current block ignoring ignorable edges and
/// ignored backedges.
SmallVector<BasicBlock *, 2> Succs;
public:
- BBState() : TopDownPathCount(0), BottomUpPathCount(0) {}
+ static const unsigned OverflowOccurredValue;
- typedef MapTy::iterator ptr_iterator;
- typedef MapTy::const_iterator ptr_const_iterator;
+ BBState() : TopDownPathCount(0), BottomUpPathCount(0) { }
- ptr_iterator top_down_ptr_begin() { return PerPtrTopDown.begin(); }
- ptr_iterator top_down_ptr_end() { return PerPtrTopDown.end(); }
- ptr_const_iterator top_down_ptr_begin() const {
+ typedef decltype(PerPtrTopDown)::iterator top_down_ptr_iterator;
+ typedef decltype(PerPtrTopDown)::const_iterator const_top_down_ptr_iterator;
+
+ top_down_ptr_iterator top_down_ptr_begin() { return PerPtrTopDown.begin(); }
+ top_down_ptr_iterator top_down_ptr_end() { return PerPtrTopDown.end(); }
+ const_top_down_ptr_iterator top_down_ptr_begin() const {
return PerPtrTopDown.begin();
}
- ptr_const_iterator top_down_ptr_end() const {
+ const_top_down_ptr_iterator top_down_ptr_end() const {
return PerPtrTopDown.end();
}
- ptr_iterator bottom_up_ptr_begin() { return PerPtrBottomUp.begin(); }
- ptr_iterator bottom_up_ptr_end() { return PerPtrBottomUp.end(); }
- ptr_const_iterator bottom_up_ptr_begin() const {
+ typedef decltype(PerPtrBottomUp)::iterator bottom_up_ptr_iterator;
+ typedef decltype(
+ PerPtrBottomUp)::const_iterator const_bottom_up_ptr_iterator;
+
+ bottom_up_ptr_iterator bottom_up_ptr_begin() {
+ return PerPtrBottomUp.begin();
+ }
+ bottom_up_ptr_iterator bottom_up_ptr_end() { return PerPtrBottomUp.end(); }
+ const_bottom_up_ptr_iterator bottom_up_ptr_begin() const {
return PerPtrBottomUp.begin();
}
- ptr_const_iterator bottom_up_ptr_end() const {
+ const_bottom_up_ptr_iterator bottom_up_ptr_end() const {
return PerPtrBottomUp.end();
}
/// definition.
void SetAsExit() { BottomUpPathCount = 1; }
- PtrState &getPtrTopDownState(const Value *Arg) {
+ /// Attempt to find the PtrState object describing the top down state for
+ /// pointer Arg. Return a new initialized PtrState describing the top down
+ /// state for Arg if we do not find one.
+ TopDownPtrState &getPtrTopDownState(const Value *Arg) {
return PerPtrTopDown[Arg];
}
- PtrState &getPtrBottomUpState(const Value *Arg) {
+ /// Attempt to find the PtrState object describing the bottom up state for
+ /// pointer Arg. Return a new initialized PtrState describing the bottom up
+ /// state for Arg if we do not find one.
+ BottomUpPtrState &getPtrBottomUpState(const Value *Arg) {
return PerPtrBottomUp[Arg];
}
+ /// Attempt to find the PtrState object describing the bottom up state for
+ /// pointer Arg.
+ bottom_up_ptr_iterator findPtrBottomUpState(const Value *Arg) {
+ return PerPtrBottomUp.find(Arg);
+ }
+
void clearBottomUpPointers() {
PerPtrBottomUp.clear();
}
void MergePred(const BBState &Other);
void MergeSucc(const BBState &Other);
- /// Return the number of possible unique paths from an entry to an exit
+ /// Compute the number of possible unique paths from an entry to an exit
/// which pass through this block. This is only valid after both the
/// top-down and bottom-up traversals are complete.
- unsigned GetAllPathCount() const {
- assert(TopDownPathCount != 0);
- assert(BottomUpPathCount != 0);
- return TopDownPathCount * BottomUpPathCount;
+ ///
+ /// Returns true if overflow occurred. Returns false if overflow did not
+ /// occur.
+ bool GetAllPathCountWithOverflow(unsigned &PathCount) const {
+ if (TopDownPathCount == OverflowOccurredValue ||
+ BottomUpPathCount == OverflowOccurredValue)
+ return true;
+ unsigned long long Product =
+ (unsigned long long)TopDownPathCount*BottomUpPathCount;
+ // Overflow occurred if any of the upper bits of Product are set or if all
+ // the lower bits of Product are all set.
+ return (Product >> 32) ||
+ ((PathCount = Product) == OverflowOccurredValue);
}
// Specialized CFG utilities.
typedef SmallVectorImpl<BasicBlock *>::const_iterator edge_iterator;
- edge_iterator pred_begin() { return Preds.begin(); }
- edge_iterator pred_end() { return Preds.end(); }
- edge_iterator succ_begin() { return Succs.begin(); }
- edge_iterator succ_end() { return Succs.end(); }
+ edge_iterator pred_begin() const { return Preds.begin(); }
+ edge_iterator pred_end() const { return Preds.end(); }
+ edge_iterator succ_begin() const { return Succs.begin(); }
+ edge_iterator succ_end() const { return Succs.end(); }
void addSucc(BasicBlock *Succ) { Succs.push_back(Succ); }
void addPred(BasicBlock *Pred) { Preds.push_back(Pred); }
bool isExit() const { return Succs.empty(); }
};
+
+ const unsigned BBState::OverflowOccurredValue = 0xffffffff;
}
void BBState::InitFromPred(const BBState &Other) {
/// The top-down traversal uses this to merge information about predecessors to
/// form the initial state for a new block.
void BBState::MergePred(const BBState &Other) {
+ if (TopDownPathCount == OverflowOccurredValue)
+ return;
+
// Other.TopDownPathCount can be 0, in which case it is either dead or a
// loop backedge. Loop backedges are special.
TopDownPathCount += Other.TopDownPathCount;
+ // In order to be consistent, we clear the top down pointers when by adding
+ // TopDownPathCount becomes OverflowOccurredValue even though "true" overflow
+ // has not occurred.
+ if (TopDownPathCount == OverflowOccurredValue) {
+ clearTopDownPointers();
+ return;
+ }
+
// Check for overflow. If we have overflow, fall back to conservative
// behavior.
if (TopDownPathCount < Other.TopDownPathCount) {
+ TopDownPathCount = OverflowOccurredValue;
clearTopDownPointers();
return;
}
// For each entry in the other set, if our set has an entry with the same key,
// merge the entries. Otherwise, copy the entry and merge it with an empty
// entry.
- for (ptr_const_iterator MI = Other.top_down_ptr_begin(),
- ME = Other.top_down_ptr_end(); MI != ME; ++MI) {
- std::pair<ptr_iterator, bool> Pair = PerPtrTopDown.insert(*MI);
- Pair.first->second.Merge(Pair.second ? PtrState() : MI->second,
+ for (auto MI = Other.top_down_ptr_begin(), ME = Other.top_down_ptr_end();
+ MI != ME; ++MI) {
+ auto Pair = PerPtrTopDown.insert(*MI);
+ Pair.first->second.Merge(Pair.second ? TopDownPtrState() : MI->second,
/*TopDown=*/true);
}
// For each entry in our set, if the other set doesn't have an entry with the
// same key, force it to merge with an empty entry.
- for (ptr_iterator MI = top_down_ptr_begin(),
- ME = top_down_ptr_end(); MI != ME; ++MI)
+ for (auto MI = top_down_ptr_begin(), ME = top_down_ptr_end(); MI != ME; ++MI)
if (Other.PerPtrTopDown.find(MI->first) == Other.PerPtrTopDown.end())
- MI->second.Merge(PtrState(), /*TopDown=*/true);
+ MI->second.Merge(TopDownPtrState(), /*TopDown=*/true);
}
/// The bottom-up traversal uses this to merge information about successors to
/// form the initial state for a new block.
void BBState::MergeSucc(const BBState &Other) {
+ if (BottomUpPathCount == OverflowOccurredValue)
+ return;
+
// Other.BottomUpPathCount can be 0, in which case it is either dead or a
// loop backedge. Loop backedges are special.
BottomUpPathCount += Other.BottomUpPathCount;
+ // In order to be consistent, we clear the top down pointers when by adding
+ // BottomUpPathCount becomes OverflowOccurredValue even though "true" overflow
+ // has not occurred.
+ if (BottomUpPathCount == OverflowOccurredValue) {
+ clearBottomUpPointers();
+ return;
+ }
+
// Check for overflow. If we have overflow, fall back to conservative
// behavior.
if (BottomUpPathCount < Other.BottomUpPathCount) {
+ BottomUpPathCount = OverflowOccurredValue;
clearBottomUpPointers();
return;
}
// For each entry in the other set, if our set has an entry with the
// same key, merge the entries. Otherwise, copy the entry and merge
// it with an empty entry.
- for (ptr_const_iterator MI = Other.bottom_up_ptr_begin(),
- ME = Other.bottom_up_ptr_end(); MI != ME; ++MI) {
- std::pair<ptr_iterator, bool> Pair = PerPtrBottomUp.insert(*MI);
- Pair.first->second.Merge(Pair.second ? PtrState() : MI->second,
+ for (auto MI = Other.bottom_up_ptr_begin(), ME = Other.bottom_up_ptr_end();
+ MI != ME; ++MI) {
+ auto Pair = PerPtrBottomUp.insert(*MI);
+ Pair.first->second.Merge(Pair.second ? BottomUpPtrState() : MI->second,
/*TopDown=*/false);
}
// For each entry in our set, if the other set doesn't have an entry
// with the same key, force it to merge with an empty entry.
- for (ptr_iterator MI = bottom_up_ptr_begin(),
- ME = bottom_up_ptr_end(); MI != ME; ++MI)
+ for (auto MI = bottom_up_ptr_begin(), ME = bottom_up_ptr_end(); MI != ME;
+ ++MI)
if (Other.PerPtrBottomUp.find(MI->first) == Other.PerPtrBottomUp.end())
- MI->second.Merge(PtrState(), /*TopDown=*/false);
+ MI->second.Merge(BottomUpPtrState(), /*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))
-
-#define ANNOTATE_BB(_states, _bb, _name, _type, _direction) \
- do { \
- if (EnableARCAnnotations) { \
- for(BBState::ptr_const_iterator I = (_states)._direction##_ptr_begin(), \
- E = (_states)._direction##_ptr_end(); I != E; ++I) { \
- Value *Ptr = const_cast<Value*>(I->first); \
- Sequence Seq = I->second.GetSeq(); \
- GenerateARCBB ## _type ## Annotation(_name, (_bb), Ptr, Seq); \
- } \
- } \
-} while (0)
-
-#define ANNOTATE_BOTTOMUP_BBSTART(_states, _basicblock) \
- ANNOTATE_BB(_states, _basicblock, "llvm.arc.annotation.bottomup.bbstart", \
- Entrance, bottom_up)
-#define ANNOTATE_BOTTOMUP_BBEND(_states, _basicblock) \
- ANNOTATE_BB(_states, _basicblock, "llvm.arc.annotation.bottomup.bbend", \
- Terminator, bottom_up)
-#define ANNOTATE_TOPDOWN_BBSTART(_states, _basicblock) \
- ANNOTATE_BB(_states, _basicblock, "llvm.arc.annotation.topdown.bbstart", \
- Entrance, top_down)
-#define ANNOTATE_TOPDOWN_BBEND(_states, _basicblock) \
- ANNOTATE_BB(_states, _basicblock, "llvm.arc.annotation.topdown.bbend", \
- Terminator, top_down)
-
-#else // !ARC_ANNOTATION
-// If annotations are off, noop.
-#define ANNOTATE_BOTTOMUP(inst, ptr, old, new)
-#define ANNOTATE_TOPDOWN(inst, ptr, old, new)
-#define ANNOTATE_BOTTOMUP_BBSTART(states, basicblock)
-#define ANNOTATE_BOTTOMUP_BBEND(states, basicblock)
-#define ANNOTATE_TOPDOWN_BBSTART(states, basicblock)
-#define ANNOTATE_TOPDOWN_BBEND(states, basicblock)
-#endif // !ARC_ANNOTATION
-
namespace {
+
/// \brief The main ARC optimization pass.
class ObjCARCOpt : public FunctionPass {
bool Changed;
ProvenanceAnalysis PA;
+ /// A cache of references to runtime entry point constants.
+ ARCRuntimeEntryPoints EP;
+
+ /// A cache of MDKinds that can be passed into other functions to propagate
+ /// MDKind identifiers.
+ ARCMDKindCache MDKindCache;
+
+ // This is used to track if a pointer is stored into an alloca.
+ DenseSet<const Value *> MultiOwnersSet;
+
/// A flag indicating whether this optimization pass should run.
bool Run;
- /// Declarations for ObjC runtime functions, for use in creating calls to
- /// them. These are initialized lazily to avoid cluttering up the Module
- /// with unused declarations.
-
- /// Declaration for ObjC runtime function
- /// objc_retainAutoreleasedReturnValue.
- Constant *RetainRVCallee;
- /// Declaration for ObjC runtime function objc_autoreleaseReturnValue.
- Constant *AutoreleaseRVCallee;
- /// Declaration for ObjC runtime function objc_release.
- Constant *ReleaseCallee;
- /// Declaration for ObjC runtime function objc_retain.
- Constant *RetainCallee;
- /// Declaration for ObjC runtime function objc_retainBlock.
- Constant *RetainBlockCallee;
- /// Declaration for ObjC runtime function objc_autorelease.
- Constant *AutoreleaseCallee;
-
/// Flags which determine whether each of the interesting runtine functions
/// is in fact used in the current function.
unsigned UsedInThisFunction;
- /// The Metadata Kind for clang.imprecise_release metadata.
- unsigned ImpreciseReleaseMDKind;
-
- /// The Metadata Kind for clang.arc.copy_on_escape metadata.
- unsigned CopyOnEscapeMDKind;
-
- /// 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);
- Constant *getRetainCallee(Module *M);
- Constant *getRetainBlockCallee(Module *M);
- Constant *getAutoreleaseCallee(Module *M);
-
- bool IsRetainBlockOptimizable(const Instruction *Inst);
-
- void OptimizeRetainCall(Function &F, Instruction *Retain);
bool OptimizeRetainRVCall(Function &F, Instruction *RetainRV);
void OptimizeAutoreleaseRVCall(Function &F, Instruction *AutoreleaseRV,
- InstructionClass &Class);
- bool OptimizeRetainBlockCall(Function &F, Instruction *RetainBlock,
- InstructionClass &Class);
+ ARCInstKind &Class);
void OptimizeIndividualCalls(Function &F);
void CheckForCFGHazards(const BasicBlock *BB,
DenseMap<const BasicBlock *, BBState> &BBStates,
BBState &MyStates) const;
- bool VisitInstructionBottomUp(Instruction *Inst,
- BasicBlock *BB,
- MapVector<Value *, RRInfo> &Retains,
+ bool VisitInstructionBottomUp(Instruction *Inst, BasicBlock *BB,
+ BlotMapVector<Value *, RRInfo> &Retains,
BBState &MyStates);
bool VisitBottomUp(BasicBlock *BB,
DenseMap<const BasicBlock *, BBState> &BBStates,
- MapVector<Value *, RRInfo> &Retains);
+ BlotMapVector<Value *, RRInfo> &Retains);
bool VisitInstructionTopDown(Instruction *Inst,
DenseMap<Value *, RRInfo> &Releases,
BBState &MyStates);
bool VisitTopDown(BasicBlock *BB,
DenseMap<const BasicBlock *, BBState> &BBStates,
DenseMap<Value *, RRInfo> &Releases);
- bool Visit(Function &F,
- DenseMap<const BasicBlock *, BBState> &BBStates,
- MapVector<Value *, RRInfo> &Retains,
+ bool Visit(Function &F, DenseMap<const BasicBlock *, BBState> &BBStates,
+ BlotMapVector<Value *, RRInfo> &Retains,
DenseMap<Value *, RRInfo> &Releases);
void MoveCalls(Value *Arg, RRInfo &RetainsToMove, RRInfo &ReleasesToMove,
- MapVector<Value *, RRInfo> &Retains,
+ BlotMapVector<Value *, RRInfo> &Retains,
DenseMap<Value *, RRInfo> &Releases,
- SmallVectorImpl<Instruction *> &DeadInsts,
- Module *M);
+ SmallVectorImpl<Instruction *> &DeadInsts, Module *M);
bool ConnectTDBUTraversals(DenseMap<const BasicBlock *, BBState> &BBStates,
- MapVector<Value *, RRInfo> &Retains,
- DenseMap<Value *, RRInfo> &Releases,
- Module *M,
- SmallVector<Instruction *, 4> &NewRetains,
- SmallVector<Instruction *, 4> &NewReleases,
- SmallVector<Instruction *, 8> &DeadInsts,
- RRInfo &RetainsToMove,
- RRInfo &ReleasesToMove,
- Value *Arg,
- bool KnownSafe,
+ BlotMapVector<Value *, RRInfo> &Retains,
+ DenseMap<Value *, RRInfo> &Releases, Module *M,
+ SmallVectorImpl<Instruction *> &NewRetains,
+ SmallVectorImpl<Instruction *> &NewReleases,
+ SmallVectorImpl<Instruction *> &DeadInsts,
+ RRInfo &RetainsToMove, RRInfo &ReleasesToMove,
+ Value *Arg, bool KnownSafe,
bool &AnyPairsCompletelyEliminated);
bool PerformCodePlacement(DenseMap<const BasicBlock *, BBState> &BBStates,
- MapVector<Value *, RRInfo> &Retains,
- DenseMap<Value *, RRInfo> &Releases,
- Module *M);
+ BlotMapVector<Value *, RRInfo> &Retains,
+ DenseMap<Value *, RRInfo> &Releases, Module *M);
void OptimizeWeakCalls(Function &F);
void OptimizeReturns(Function &F);
- virtual void getAnalysisUsage(AnalysisUsage &AU) const;
- virtual bool doInitialization(Module &M);
- virtual bool runOnFunction(Function &F);
- virtual void releaseMemory();
+#ifndef NDEBUG
+ void GatherStatistics(Function &F, bool AfterOptimization = false);
+#endif
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override;
+ bool doInitialization(Module &M) override;
+ bool runOnFunction(Function &F) override;
+ void releaseMemory() override;
public:
static char ID;
AU.setPreservesCFG();
}
-bool ObjCARCOpt::IsRetainBlockOptimizable(const Instruction *Inst) {
- // Without the magic metadata tag, we have to assume this might be an
- // objc_retainBlock call inserted to convert a block pointer to an id,
- // in which case it really is needed.
- if (!Inst->getMetadata(CopyOnEscapeMDKind))
- return false;
-
- // If the pointer "escapes" (not including being used in a call),
- // the copy may be needed.
- if (DoesRetainableObjPtrEscape(Inst))
- return false;
-
- // Otherwise, it's not needed.
- return true;
-}
-
-Constant *ObjCARCOpt::getRetainRVCallee(Module *M) {
- if (!RetainRVCallee) {
- LLVMContext &C = M->getContext();
- Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
- Type *Params[] = { I8X };
- FunctionType *FTy = FunctionType::get(I8X, Params, /*isVarArg=*/false);
- AttributeSet Attribute =
- AttributeSet().addAttribute(M->getContext(), AttributeSet::FunctionIndex,
- Attribute::NoUnwind);
- RetainRVCallee =
- M->getOrInsertFunction("objc_retainAutoreleasedReturnValue", FTy,
- Attribute);
- }
- return RetainRVCallee;
-}
-
-Constant *ObjCARCOpt::getAutoreleaseRVCallee(Module *M) {
- if (!AutoreleaseRVCallee) {
- LLVMContext &C = M->getContext();
- Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
- Type *Params[] = { I8X };
- FunctionType *FTy = FunctionType::get(I8X, Params, /*isVarArg=*/false);
- AttributeSet Attribute =
- AttributeSet().addAttribute(M->getContext(), AttributeSet::FunctionIndex,
- Attribute::NoUnwind);
- AutoreleaseRVCallee =
- M->getOrInsertFunction("objc_autoreleaseReturnValue", FTy,
- Attribute);
- }
- return AutoreleaseRVCallee;
-}
-
-Constant *ObjCARCOpt::getReleaseCallee(Module *M) {
- if (!ReleaseCallee) {
- LLVMContext &C = M->getContext();
- Type *Params[] = { PointerType::getUnqual(Type::getInt8Ty(C)) };
- AttributeSet Attribute =
- AttributeSet().addAttribute(M->getContext(), AttributeSet::FunctionIndex,
- Attribute::NoUnwind);
- ReleaseCallee =
- M->getOrInsertFunction(
- "objc_release",
- FunctionType::get(Type::getVoidTy(C), Params, /*isVarArg=*/false),
- Attribute);
- }
- return ReleaseCallee;
-}
-
-Constant *ObjCARCOpt::getRetainCallee(Module *M) {
- if (!RetainCallee) {
- LLVMContext &C = M->getContext();
- Type *Params[] = { PointerType::getUnqual(Type::getInt8Ty(C)) };
- AttributeSet Attribute =
- AttributeSet().addAttribute(M->getContext(), AttributeSet::FunctionIndex,
- Attribute::NoUnwind);
- RetainCallee =
- M->getOrInsertFunction(
- "objc_retain",
- FunctionType::get(Params[0], Params, /*isVarArg=*/false),
- Attribute);
- }
- return RetainCallee;
-}
-
-Constant *ObjCARCOpt::getRetainBlockCallee(Module *M) {
- if (!RetainBlockCallee) {
- LLVMContext &C = M->getContext();
- Type *Params[] = { PointerType::getUnqual(Type::getInt8Ty(C)) };
- // objc_retainBlock is not nounwind because it calls user copy constructors
- // which could theoretically throw.
- RetainBlockCallee =
- M->getOrInsertFunction(
- "objc_retainBlock",
- FunctionType::get(Params[0], Params, /*isVarArg=*/false),
- AttributeSet());
- }
- return RetainBlockCallee;
-}
-
-Constant *ObjCARCOpt::getAutoreleaseCallee(Module *M) {
- if (!AutoreleaseCallee) {
- LLVMContext &C = M->getContext();
- Type *Params[] = { PointerType::getUnqual(Type::getInt8Ty(C)) };
- AttributeSet Attribute =
- AttributeSet().addAttribute(M->getContext(), AttributeSet::FunctionIndex,
- Attribute::NoUnwind);
- AutoreleaseCallee =
- M->getOrInsertFunction(
- "objc_autorelease",
- FunctionType::get(Params[0], Params, /*isVarArg=*/false),
- Attribute);
- }
- return AutoreleaseCallee;
-}
-
-/// Turn objc_retain into objc_retainAutoreleasedReturnValue if the operand is a
-/// return value.
-void
-ObjCARCOpt::OptimizeRetainCall(Function &F, Instruction *Retain) {
- ImmutableCallSite CS(GetObjCArg(Retain));
- const Instruction *Call = CS.getInstruction();
- if (!Call) return;
- if (Call->getParent() != Retain->getParent()) return;
-
- // Check that the call is next to the retain.
- BasicBlock::const_iterator I = Call;
- ++I;
- while (IsNoopInstruction(I)) ++I;
- if (&*I != Retain)
- return;
-
- // Turn it to an objc_retainAutoreleasedReturnValue..
- Changed = true;
- ++NumPeeps;
-
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeRetainCall: Transforming "
- "objc_retain => objc_retainAutoreleasedReturnValue"
- " since the operand is a return value.\n"
- " Old: "
- << *Retain << "\n");
-
- cast<CallInst>(Retain)->setCalledFunction(getRetainRVCallee(F.getParent()));
-
- DEBUG(dbgs() << " New: "
- << *Retain << "\n");
-}
-
/// Turn objc_retainAutoreleasedReturnValue into objc_retain if the operand is
/// not a return value. Or, if it can be paired with an
/// objc_autoreleaseReturnValue, delete the pair and return true.
bool
ObjCARCOpt::OptimizeRetainRVCall(Function &F, Instruction *RetainRV) {
// Check for the argument being from an immediately preceding call or invoke.
- const Value *Arg = GetObjCArg(RetainRV);
+ const Value *Arg = GetArgRCIdentityRoot(RetainRV);
ImmutableCallSite CS(Arg);
if (const Instruction *Call = CS.getInstruction()) {
if (Call->getParent() == RetainRV->getParent()) {
BasicBlock::iterator I = RetainRV, Begin = RetainRV->getParent()->begin();
if (I != Begin) {
do --I; while (I != Begin && IsNoopInstruction(I));
- if (GetBasicInstructionClass(I) == IC_AutoreleaseRV &&
- GetObjCArg(I) == Arg) {
+ if (GetBasicARCInstKind(I) == ARCInstKind::AutoreleaseRV &&
+ GetArgRCIdentityRoot(I) == Arg) {
Changed = true;
++NumPeeps;
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeRetainRVCall: Erasing " << *I << "\n"
- << " Erasing " << *RetainRV
- << "\n");
+ DEBUG(dbgs() << "Erasing autoreleaseRV,retainRV pair: " << *I << "\n"
+ << "Erasing " << *RetainRV << "\n");
EraseInstruction(I);
EraseInstruction(RetainRV);
Changed = true;
++NumPeeps;
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeRetainRVCall: Transforming "
- "objc_retainAutoreleasedReturnValue => "
+ DEBUG(dbgs() << "Transforming objc_retainAutoreleasedReturnValue => "
"objc_retain since the operand is not a return value.\n"
- " Old: "
- << *RetainRV << "\n");
+ "Old = " << *RetainRV << "\n");
- cast<CallInst>(RetainRV)->setCalledFunction(getRetainCallee(F.getParent()));
+ Constant *NewDecl = EP.get(ARCRuntimeEntryPoints::EPT_Retain);
+ cast<CallInst>(RetainRV)->setCalledFunction(NewDecl);
- DEBUG(dbgs() << " New: "
- << *RetainRV << "\n");
+ DEBUG(dbgs() << "New = " << *RetainRV << "\n");
return false;
}
/// Turn objc_autoreleaseReturnValue into objc_autorelease if the result is not
/// used as a return value.
-void
-ObjCARCOpt::OptimizeAutoreleaseRVCall(Function &F, Instruction *AutoreleaseRV,
- InstructionClass &Class) {
+void ObjCARCOpt::OptimizeAutoreleaseRVCall(Function &F,
+ Instruction *AutoreleaseRV,
+ ARCInstKind &Class) {
// Check for a return of the pointer value.
- const Value *Ptr = GetObjCArg(AutoreleaseRV);
+ const Value *Ptr = GetArgRCIdentityRoot(AutoreleaseRV);
SmallVector<const Value *, 2> Users;
Users.push_back(Ptr);
do {
Ptr = Users.pop_back_val();
- for (Value::const_use_iterator UI = Ptr->use_begin(), UE = Ptr->use_end();
- UI != UE; ++UI) {
- const User *I = *UI;
- if (isa<ReturnInst>(I) || GetBasicInstructionClass(I) == IC_RetainRV)
+ for (const User *U : Ptr->users()) {
+ if (isa<ReturnInst>(U) || GetBasicARCInstKind(U) == ARCInstKind::RetainRV)
return;
- if (isa<BitCastInst>(I))
- Users.push_back(I);
+ if (isa<BitCastInst>(U))
+ Users.push_back(U);
}
} while (!Users.empty());
Changed = true;
++NumPeeps;
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeAutoreleaseRVCall: Transforming "
- "objc_autoreleaseReturnValue => "
+ DEBUG(dbgs() << "Transforming objc_autoreleaseReturnValue => "
"objc_autorelease since its operand is not used as a return "
"value.\n"
- " Old: "
- << *AutoreleaseRV << "\n");
+ "Old = " << *AutoreleaseRV << "\n");
CallInst *AutoreleaseRVCI = cast<CallInst>(AutoreleaseRV);
- AutoreleaseRVCI->
- setCalledFunction(getAutoreleaseCallee(F.getParent()));
+ Constant *NewDecl = EP.get(ARCRuntimeEntryPoints::EPT_Autorelease);
+ AutoreleaseRVCI->setCalledFunction(NewDecl);
AutoreleaseRVCI->setTailCall(false); // Never tail call objc_autorelease.
- Class = IC_Autorelease;
+ Class = ARCInstKind::Autorelease;
- DEBUG(dbgs() << " New: "
- << *AutoreleaseRV << "\n");
+ DEBUG(dbgs() << "New: " << *AutoreleaseRV << "\n");
}
-// \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) {
+ DEBUG(dbgs() << "\n== ObjCARCOpt::OptimizeIndividualCalls ==\n");
// Reset all the flags in preparation for recomputing them.
UsedInThisFunction = 0;
for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ) {
Instruction *Inst = &*I++;
- InstructionClass Class = GetBasicInstructionClass(Inst);
+ ARCInstKind Class = GetBasicARCInstKind(Inst);
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Visiting: Class: "
- << Class << "; " << *Inst << "\n");
+ DEBUG(dbgs() << "Visiting: Class: " << Class << "; " << *Inst << "\n");
switch (Class) {
default: break;
// There are gray areas here, as the ability to cast reference-counted
// pointers to raw void* and back allows code to break ARC assumptions,
// however these are currently considered to be unimportant.
- case IC_NoopCast:
+ case ARCInstKind::NoopCast:
Changed = true;
++NumNoops;
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Erasing no-op cast:"
- " " << *Inst << "\n");
+ DEBUG(dbgs() << "Erasing no-op cast: " << *Inst << "\n");
EraseInstruction(Inst);
continue;
// If the pointer-to-weak-pointer is null, it's undefined behavior.
- case IC_StoreWeak:
- case IC_LoadWeak:
- case IC_LoadWeakRetained:
- case IC_InitWeak:
- case IC_DestroyWeak: {
+ case ARCInstKind::StoreWeak:
+ case ARCInstKind::LoadWeak:
+ case ARCInstKind::LoadWeakRetained:
+ case ARCInstKind::InitWeak:
+ case ARCInstKind::DestroyWeak: {
CallInst *CI = cast<CallInst>(Inst);
if (IsNullOrUndef(CI->getArgOperand(0))) {
Changed = true;
Constant::getNullValue(Ty),
CI);
llvm::Value *NewValue = UndefValue::get(CI->getType());
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: A null "
- "pointer-to-weak-pointer is undefined behavior.\n"
- " Old = " << *CI <<
- "\n New = " <<
- *NewValue << "\n");
+ DEBUG(dbgs() << "A null pointer-to-weak-pointer is undefined behavior."
+ "\nOld = " << *CI << "\nNew = " << *NewValue << "\n");
CI->replaceAllUsesWith(NewValue);
CI->eraseFromParent();
continue;
}
break;
}
- case IC_CopyWeak:
- case IC_MoveWeak: {
+ case ARCInstKind::CopyWeak:
+ case ARCInstKind::MoveWeak: {
CallInst *CI = cast<CallInst>(Inst);
if (IsNullOrUndef(CI->getArgOperand(0)) ||
IsNullOrUndef(CI->getArgOperand(1))) {
CI);
llvm::Value *NewValue = UndefValue::get(CI->getType());
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: A null "
- "pointer-to-weak-pointer is undefined behavior.\n"
- " Old = " << *CI <<
- "\n New = " <<
- *NewValue << "\n");
+ DEBUG(dbgs() << "A null pointer-to-weak-pointer is undefined behavior."
+ "\nOld = " << *CI << "\nNew = " << *NewValue << "\n");
CI->replaceAllUsesWith(NewValue);
CI->eraseFromParent();
}
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;
- case IC_RetainRV:
+ case ARCInstKind::RetainRV:
if (OptimizeRetainRVCall(F, Inst))
continue;
break;
- case IC_AutoreleaseRV:
+ case ARCInstKind::AutoreleaseRV:
OptimizeAutoreleaseRVCall(F, Inst, Class);
break;
}
// Create the declaration lazily.
LLVMContext &C = Inst->getContext();
- CallInst *NewCall =
- CallInst::Create(getReleaseCallee(F.getParent()),
- Call->getArgOperand(0), "", Call);
- NewCall->setMetadata(ImpreciseReleaseMDKind,
- MDNode::get(C, ArrayRef<Value *>()));
-
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Replacing "
- "objc_autorelease(x) with objc_release(x) since x is "
- "otherwise unused.\n"
- " Old: " << *Call <<
- "\n New: " <<
- *NewCall << "\n");
+
+ Constant *Decl = EP.get(ARCRuntimeEntryPoints::EPT_Release);
+ CallInst *NewCall = CallInst::Create(Decl, Call->getArgOperand(0), "",
+ Call);
+ NewCall->setMetadata(MDKindCache.ImpreciseReleaseMDKind,
+ MDNode::get(C, None));
+
+ DEBUG(dbgs() << "Replacing autorelease{,RV}(x) with objc_release(x) "
+ "since x is otherwise unused.\nOld: " << *Call << "\nNew: "
+ << *NewCall << "\n");
EraseInstruction(Call);
Inst = NewCall;
- Class = IC_Release;
+ Class = ARCInstKind::Release;
}
}
// a tail keyword.
if (IsAlwaysTail(Class)) {
Changed = true;
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Adding tail keyword"
- " to function since it can never be passed stack args: " << *Inst <<
- "\n");
+ DEBUG(dbgs() << "Adding tail keyword to function since it can never be "
+ "passed stack args: " << *Inst << "\n");
cast<CallInst>(Inst)->setTailCall();
}
// semantics of ARC truly do not do so.
if (IsNeverTail(Class)) {
Changed = true;
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Removing tail "
- "keyword from function: " << *Inst <<
+ DEBUG(dbgs() << "Removing tail keyword from function: " << *Inst <<
"\n");
cast<CallInst>(Inst)->setTailCall(false);
}
// Set nounwind as needed.
if (IsNoThrow(Class)) {
Changed = true;
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Found no throw"
- " class. Setting nounwind on: " << *Inst << "\n");
+ DEBUG(dbgs() << "Found no throw class. Setting nounwind on: " << *Inst
+ << "\n");
cast<CallInst>(Inst)->setDoesNotThrow();
}
if (!IsNoopOnNull(Class)) {
- UsedInThisFunction |= 1 << Class;
+ UsedInThisFunction |= 1 << unsigned(Class);
continue;
}
- const Value *Arg = GetObjCArg(Inst);
+ const Value *Arg = GetArgRCIdentityRoot(Inst);
// ARC calls with null are no-ops. Delete them.
if (IsNullOrUndef(Arg)) {
Changed = true;
++NumNoops;
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: ARC calls with "
- " null are no-ops. Erasing: " << *Inst << "\n");
+ DEBUG(dbgs() << "ARC calls with null are no-ops. Erasing: " << *Inst
+ << "\n");
EraseInstruction(Inst);
continue;
}
// Keep track of which of retain, release, autorelease, and retain_block
// are actually present in this function.
- UsedInThisFunction |= 1 << Class;
+ UsedInThisFunction |= 1 << unsigned(Class);
// If Arg is a PHI, and one or more incoming values to the
// PHI are null, and the call is control-equivalent to the PHI, and there
bool HasCriticalEdges = false;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
Value *Incoming =
- StripPointerCastsAndObjCCalls(PN->getIncomingValue(i));
+ GetRCIdentityRoot(PN->getIncomingValue(i));
if (IsNullOrUndef(Incoming))
HasNull = true;
else if (cast<TerminatorInst>(PN->getIncomingBlock(i)->back())
// Check that there is nothing that cares about the reference
// count between the call and the phi.
switch (Class) {
- case IC_Retain:
- case IC_RetainBlock:
+ case ARCInstKind::Retain:
+ case ARCInstKind::RetainBlock:
// These can always be moved up.
break;
- case IC_Release:
+ case ARCInstKind::Release:
// These can't be moved across things that care about the retain
// count.
FindDependencies(NeedsPositiveRetainCount, Arg,
Inst->getParent(), Inst,
DependingInstructions, Visited, PA);
break;
- case IC_Autorelease:
+ case ARCInstKind::Autorelease:
// These can't be moved across autorelease pool scope boundaries.
FindDependencies(AutoreleasePoolBoundary, Arg,
Inst->getParent(), Inst,
DependingInstructions, Visited, PA);
break;
- case IC_RetainRV:
- case IC_AutoreleaseRV:
+ case ARCInstKind::RetainRV:
+ case ARCInstKind::AutoreleaseRV:
// Don't move these; the RV optimization depends on the autoreleaseRV
// being tail called, and the retainRV being immediately after a call
// (which might still happen if we get lucky with codegen layout, but
Type *ParamTy = CInst->getArgOperand(0)->getType();
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
Value *Incoming =
- StripPointerCastsAndObjCCalls(PN->getIncomingValue(i));
+ GetRCIdentityRoot(PN->getIncomingValue(i));
if (!IsNullOrUndef(Incoming)) {
CallInst *Clone = cast<CallInst>(CInst->clone());
Value *Op = PN->getIncomingValue(i);
Clone->setArgOperand(0, Op);
Clone->insertBefore(InsertPos);
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Cloning "
+ DEBUG(dbgs() << "Cloning "
<< *CInst << "\n"
- " And inserting "
- "clone at " << *InsertPos << "\n");
+ "And inserting clone at " << *InsertPos << "\n");
Worklist.push_back(std::make_pair(Clone, Incoming));
}
}
}
} while (!Worklist.empty());
}
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Finished List.\n");
+}
+
+/// If we have a top down pointer in the S_Use state, make sure that there are
+/// no CFG hazards by checking the states of various bottom up pointers.
+static void CheckForUseCFGHazard(const Sequence SuccSSeq,
+ const bool SuccSRRIKnownSafe,
+ TopDownPtrState &S,
+ bool &SomeSuccHasSame,
+ bool &AllSuccsHaveSame,
+ bool &NotAllSeqEqualButKnownSafe,
+ bool &ShouldContinue) {
+ switch (SuccSSeq) {
+ case S_CanRelease: {
+ if (!S.IsKnownSafe() && !SuccSRRIKnownSafe) {
+ S.ClearSequenceProgress();
+ break;
+ }
+ S.SetCFGHazardAfflicted(true);
+ ShouldContinue = true;
+ break;
+ }
+ case S_Use:
+ SomeSuccHasSame = true;
+ break;
+ case S_Stop:
+ case S_Release:
+ case S_MovableRelease:
+ if (!S.IsKnownSafe() && !SuccSRRIKnownSafe)
+ AllSuccsHaveSame = false;
+ else
+ NotAllSeqEqualButKnownSafe = true;
+ break;
+ case S_Retain:
+ llvm_unreachable("bottom-up pointer in retain state!");
+ case S_None:
+ llvm_unreachable("This should have been handled earlier.");
+ }
+}
+
+/// If we have a Top Down pointer in the S_CanRelease state, make sure that
+/// there are no CFG hazards by checking the states of various bottom up
+/// pointers.
+static void CheckForCanReleaseCFGHazard(const Sequence SuccSSeq,
+ const bool SuccSRRIKnownSafe,
+ TopDownPtrState &S,
+ bool &SomeSuccHasSame,
+ bool &AllSuccsHaveSame,
+ bool &NotAllSeqEqualButKnownSafe) {
+ switch (SuccSSeq) {
+ case S_CanRelease:
+ SomeSuccHasSame = true;
+ break;
+ case S_Stop:
+ case S_Release:
+ case S_MovableRelease:
+ case S_Use:
+ if (!S.IsKnownSafe() && !SuccSRRIKnownSafe)
+ AllSuccsHaveSame = false;
+ else
+ NotAllSeqEqualButKnownSafe = true;
+ break;
+ case S_Retain:
+ llvm_unreachable("bottom-up pointer in retain state!");
+ case S_None:
+ llvm_unreachable("This should have been handled earlier.");
+ }
}
/// Check for critical edges, loop boundaries, irreducible control flow, or
BBState &MyStates) const {
// If any top-down local-use or possible-dec has a succ which is earlier in
// the sequence, forget it.
- for (BBState::ptr_iterator I = MyStates.top_down_ptr_begin(),
- E = MyStates.top_down_ptr_end(); I != E; ++I)
- switch (I->second.GetSeq()) {
- default: break;
- case S_Use: {
- const Value *Arg = I->first;
- const TerminatorInst *TI = cast<TerminatorInst>(&BB->back());
- bool SomeSuccHasSame = false;
- bool AllSuccsHaveSame = true;
- PtrState &S = I->second;
- succ_const_iterator SI(TI), SE(TI, false);
-
- for (; SI != SE; ++SI) {
- Sequence SuccSSeq = S_None;
- bool SuccSRRIKnownSafe = false;
- // If VisitBottomUp has pointer information for this successor, take
- // what we know about it.
- DenseMap<const BasicBlock *, BBState>::iterator BBI =
- BBStates.find(*SI);
- assert(BBI != BBStates.end());
- const PtrState &SuccS = BBI->second.getPtrBottomUpState(Arg);
- SuccSSeq = SuccS.GetSeq();
- SuccSRRIKnownSafe = SuccS.RRI.KnownSafe;
- switch (SuccSSeq) {
- case S_None:
- case S_CanRelease: {
- if (!S.RRI.KnownSafe && !SuccSRRIKnownSafe) {
- S.ClearSequenceProgress();
- break;
- }
- continue;
- }
- case S_Use:
- SomeSuccHasSame = true;
- break;
- case S_Stop:
- case S_Release:
- case S_MovableRelease:
- if (!S.RRI.KnownSafe && !SuccSRRIKnownSafe)
- AllSuccsHaveSame = false;
- break;
- case S_Retain:
- llvm_unreachable("bottom-up pointer in retain state!");
- }
- }
- // If the state at the other end of any of the successor edges
- // matches the current state, require all edges to match. This
- // guards against loops in the middle of a sequence.
- if (SomeSuccHasSame && !AllSuccsHaveSame)
+ for (auto I = MyStates.top_down_ptr_begin(), E = MyStates.top_down_ptr_end();
+ I != E; ++I) {
+ TopDownPtrState &S = I->second;
+ const Sequence Seq = I->second.GetSeq();
+
+ // We only care about S_Retain, S_CanRelease, and S_Use.
+ if (Seq == S_None)
+ continue;
+
+ // Make sure that if extra top down states are added in the future that this
+ // code is updated to handle it.
+ assert((Seq == S_Retain || Seq == S_CanRelease || Seq == S_Use) &&
+ "Unknown top down sequence state.");
+
+ const Value *Arg = I->first;
+ const TerminatorInst *TI = cast<TerminatorInst>(&BB->back());
+ bool SomeSuccHasSame = false;
+ bool AllSuccsHaveSame = true;
+ bool NotAllSeqEqualButKnownSafe = false;
+
+ succ_const_iterator SI(TI), SE(TI, false);
+
+ for (; SI != SE; ++SI) {
+ // If VisitBottomUp has pointer information for this successor, take
+ // what we know about it.
+ const DenseMap<const BasicBlock *, BBState>::iterator BBI =
+ BBStates.find(*SI);
+ assert(BBI != BBStates.end());
+ const BottomUpPtrState &SuccS = BBI->second.getPtrBottomUpState(Arg);
+ const Sequence SuccSSeq = SuccS.GetSeq();
+
+ // If bottom up, the pointer is in an S_None state, clear the sequence
+ // progress since the sequence in the bottom up state finished
+ // suggesting a mismatch in between retains/releases. This is true for
+ // all three cases that we are handling here: S_Retain, S_Use, and
+ // S_CanRelease.
+ if (SuccSSeq == S_None) {
S.ClearSequenceProgress();
- break;
- }
- case S_CanRelease: {
- const Value *Arg = I->first;
- const TerminatorInst *TI = cast<TerminatorInst>(&BB->back());
- bool SomeSuccHasSame = false;
- bool AllSuccsHaveSame = true;
- PtrState &S = I->second;
- succ_const_iterator SI(TI), SE(TI, false);
-
- for (; SI != SE; ++SI) {
- Sequence SuccSSeq = S_None;
- bool SuccSRRIKnownSafe = false;
- // If VisitBottomUp has pointer information for this successor, take
- // what we know about it.
- DenseMap<const BasicBlock *, BBState>::iterator BBI =
- BBStates.find(*SI);
- assert(BBI != BBStates.end());
- const PtrState &SuccS = BBI->second.getPtrBottomUpState(Arg);
- SuccSSeq = SuccS.GetSeq();
- SuccSRRIKnownSafe = SuccS.RRI.KnownSafe;
- switch (SuccSSeq) {
- case S_None: {
- if (!S.RRI.KnownSafe && !SuccSRRIKnownSafe) {
- S.ClearSequenceProgress();
- break;
- }
+ continue;
+ }
+
+ // If we have S_Use or S_CanRelease, perform our check for cfg hazard
+ // checks.
+ const bool SuccSRRIKnownSafe = SuccS.IsKnownSafe();
+
+ // *NOTE* We do not use Seq from above here since we are allowing for
+ // S.GetSeq() to change while we are visiting basic blocks.
+ switch(S.GetSeq()) {
+ case S_Use: {
+ bool ShouldContinue = false;
+ CheckForUseCFGHazard(SuccSSeq, SuccSRRIKnownSafe, S, SomeSuccHasSame,
+ AllSuccsHaveSame, NotAllSeqEqualButKnownSafe,
+ ShouldContinue);
+ if (ShouldContinue)
continue;
- }
- case S_CanRelease:
- SomeSuccHasSame = true;
- break;
- case S_Stop:
- case S_Release:
- case S_MovableRelease:
- case S_Use:
- if (!S.RRI.KnownSafe && !SuccSRRIKnownSafe)
- AllSuccsHaveSame = false;
- break;
- case S_Retain:
- llvm_unreachable("bottom-up pointer in retain state!");
- }
+ break;
+ }
+ case S_CanRelease: {
+ CheckForCanReleaseCFGHazard(SuccSSeq, SuccSRRIKnownSafe, S,
+ SomeSuccHasSame, AllSuccsHaveSame,
+ NotAllSeqEqualButKnownSafe);
+ break;
+ }
+ case S_Retain:
+ case S_None:
+ case S_Stop:
+ case S_Release:
+ case S_MovableRelease:
+ break;
}
- // If the state at the other end of any of the successor edges
- // matches the current state, require all edges to match. This
- // guards against loops in the middle of a sequence.
- if (SomeSuccHasSame && !AllSuccsHaveSame)
- S.ClearSequenceProgress();
- break;
}
+
+ // If the state at the other end of any of the successor edges
+ // matches the current state, require all edges to match. This
+ // guards against loops in the middle of a sequence.
+ if (SomeSuccHasSame && !AllSuccsHaveSame) {
+ S.ClearSequenceProgress();
+ } else if (NotAllSeqEqualButKnownSafe) {
+ // If we would have cleared the state foregoing the fact that we are known
+ // safe, stop code motion. This is because whether or not it is safe to
+ // remove RR pairs via KnownSafe is an orthogonal concept to whether we
+ // are allowed to perform code motion.
+ S.SetCFGHazardAfflicted(true);
}
+ }
}
-bool
-ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst,
- BasicBlock *BB,
- MapVector<Value *, RRInfo> &Retains,
- BBState &MyStates) {
+bool ObjCARCOpt::VisitInstructionBottomUp(
+ Instruction *Inst, BasicBlock *BB, BlotMapVector<Value *, RRInfo> &Retains,
+ BBState &MyStates) {
bool NestingDetected = false;
- InstructionClass Class = GetInstructionClass(Inst);
- const Value *Arg = 0;
+ ARCInstKind Class = GetARCInstKind(Inst);
+ const Value *Arg = nullptr;
+
+ DEBUG(dbgs() << "Class: " << Class << "\n");
switch (Class) {
- case IC_Release: {
- Arg = GetObjCArg(Inst);
+ case ARCInstKind::Release: {
+ Arg = GetArgRCIdentityRoot(Inst);
- PtrState &S = MyStates.getPtrBottomUpState(Arg);
+ BottomUpPtrState &S = MyStates.getPtrBottomUpState(Arg);
// If we see two releases in a row on the same pointer. If so, make
// a note, and we'll cicle back to revisit it after we've
// pairs by making PtrState hold a stack of states, but this is
// simple and avoids adding overhead for the non-nested case.
if (S.GetSeq() == S_Release || S.GetSeq() == S_MovableRelease) {
- DEBUG(dbgs() << "ObjCARCOpt::VisitInstructionBottomUp: Found nested "
- "releases (i.e. a release pair)\n");
+ DEBUG(dbgs() << "Found nested releases (i.e. a release pair)\n");
NestingDetected = true;
}
- MDNode *ReleaseMetadata = Inst->getMetadata(ImpreciseReleaseMDKind);
+ MDNode *ReleaseMetadata =
+ Inst->getMetadata(MDKindCache.ImpreciseReleaseMDKind);
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.SetReleaseMetadata(ReleaseMetadata);
+ S.SetKnownSafe(S.HasKnownPositiveRefCount());
+ S.SetTailCallRelease(cast<CallInst>(Inst)->isTailCall());
+ S.InsertCall(Inst);
S.SetKnownPositiveRefCount();
break;
}
- case IC_RetainBlock:
+ case ARCInstKind::RetainBlock:
// 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);
+ case ARCInstKind::Retain:
+ case ARCInstKind::RetainRV: {
+ Arg = GetArgRCIdentityRoot(Inst);
- PtrState &S = MyStates.getPtrBottomUpState(Arg);
+ BottomUpPtrState &S = MyStates.getPtrBottomUpState(Arg);
S.SetKnownPositiveRefCount();
Sequence OldSeq = S.GetSeq();
case S_Release:
case S_MovableRelease:
case S_Use:
- S.RRI.ReverseInsertPts.clear();
+ // If OldSeq is not S_Use or OldSeq is S_Use and we are tracking an
+ // imprecise release, clear our reverse insertion points.
+ if (OldSeq != S_Use || S.IsTrackingImpreciseReleases())
+ S.ClearReverseInsertPts();
// FALL THROUGH
case S_CanRelease:
- // Don't do retain+release tracking for IC_RetainRV, because it's
+ // Don't do retain+release tracking for ARCInstKind::RetainRV,
+ // because it's
// better to let it remain as the first instruction after a call.
- if (Class != IC_RetainRV)
- Retains[Inst] = S.RRI;
+ if (Class != ARCInstKind::RetainRV)
+ Retains[Inst] = S.GetRRInfo();
S.ClearSequenceProgress();
break;
case S_None:
case S_Retain:
llvm_unreachable("bottom-up pointer in retain state!");
}
- ANNOTATE_BOTTOMUP(Inst, Arg, OldSeq, S.GetSeq());
- return NestingDetected;
+ // A retain moving bottom up can be a use.
+ break;
}
- case IC_AutoreleasepoolPop:
+ case ARCInstKind::AutoreleasepoolPop:
// Conservatively, clear MyStates for all known pointers.
MyStates.clearBottomUpPointers();
return NestingDetected;
- case IC_AutoreleasepoolPush:
- case IC_None:
+ case ARCInstKind::AutoreleasepoolPush:
+ case ARCInstKind::None:
// These are irrelevant.
return NestingDetected;
+ case ARCInstKind::User:
+ // If we have a store into an alloca of a pointer we are tracking, the
+ // pointer has multiple owners implying that we must be more conservative.
+ //
+ // This comes up in the context of a pointer being ``KnownSafe''. In the
+ // presence of a block being initialized, the frontend will emit the
+ // objc_retain on the original pointer and the release on the pointer loaded
+ // from the alloca. The optimizer will through the provenance analysis
+ // realize that the two are related, but since we only require KnownSafe in
+ // one direction, will match the inner retain on the original pointer with
+ // the guard release on the original pointer. This is fixed by ensuring that
+ // in the presence of allocas we only unconditionally remove pointers if
+ // both our retain and our release are KnownSafe.
+ if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
+ if (AreAnyUnderlyingObjectsAnAlloca(SI->getPointerOperand())) {
+ auto I = MyStates.findPtrBottomUpState(
+ GetRCIdentityRoot(SI->getValueOperand()));
+ if (I != MyStates.bottom_up_ptr_end())
+ MultiOwnersSet.insert(I->first);
+ }
+ }
+ break;
default:
break;
}
// Consider any other possible effects of this instruction on each
// pointer being tracked.
- for (BBState::ptr_iterator MI = MyStates.bottom_up_ptr_begin(),
- ME = MyStates.bottom_up_ptr_end(); MI != ME; ++MI) {
+ for (auto MI = MyStates.bottom_up_ptr_begin(),
+ ME = MyStates.bottom_up_ptr_end();
+ MI != ME; ++MI) {
const Value *Ptr = MI->first;
if (Ptr == Arg)
continue; // Handled above.
- PtrState &S = MI->second;
+ BottomUpPtrState &S = MI->second;
Sequence Seq = S.GetSeq();
// Check for possible releases.
if (CanAlterRefCount(Inst, Ptr, PA, Class)) {
+ DEBUG(dbgs() << "CanAlterRefCount: Seq: " << Seq << "; " << *Ptr
+ << "\n");
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:
case S_Release:
case S_MovableRelease:
if (CanUse(Inst, Ptr, PA, Class)) {
- assert(S.RRI.ReverseInsertPts.empty());
+ DEBUG(dbgs() << "CanUse: Seq: " << Seq << "; " << *Ptr
+ << "\n");
+ assert(!S.HasReverseInsertPts());
// If this is an invoke instruction, we're scanning it as part of
// one of its successor blocks, since we can't insert code after it
// in its own block, and we don't want to split critical edges.
if (isa<InvokeInst>(Inst))
- S.RRI.ReverseInsertPts.insert(BB->getFirstInsertionPt());
+ S.InsertReverseInsertPt(BB->getFirstInsertionPt());
else
- S.RRI.ReverseInsertPts.insert(llvm::next(BasicBlock::iterator(Inst)));
+ S.InsertReverseInsertPt(std::next(BasicBlock::iterator(Inst)));
S.SetSeq(S_Use);
- ANNOTATE_BOTTOMUP(Inst, Ptr, Seq, S_Use);
} else if (Seq == S_Release && IsUser(Class)) {
+ DEBUG(dbgs() << "PreciseReleaseUse: Seq: " << Seq << "; " << *Ptr
+ << "\n");
// 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());
+ assert(!S.HasReverseInsertPts());
// As above; handle invoke specially.
if (isa<InvokeInst>(Inst))
- S.RRI.ReverseInsertPts.insert(BB->getFirstInsertionPt());
+ S.InsertReverseInsertPt(BB->getFirstInsertionPt());
else
- S.RRI.ReverseInsertPts.insert(llvm::next(BasicBlock::iterator(Inst)));
+ S.InsertReverseInsertPt(std::next(BasicBlock::iterator(Inst)));
}
break;
case S_Stop:
if (CanUse(Inst, Ptr, PA, Class)) {
+ DEBUG(dbgs() << "PreciseStopUse: Seq: " << Seq << "; " << *Ptr
+ << "\n");
S.SetSeq(S_Use);
- ANNOTATE_BOTTOMUP(Inst, Ptr, Seq, S_Use);
}
break;
case S_CanRelease:
return NestingDetected;
}
-bool
-ObjCARCOpt::VisitBottomUp(BasicBlock *BB,
- DenseMap<const BasicBlock *, BBState> &BBStates,
- MapVector<Value *, RRInfo> &Retains) {
+bool ObjCARCOpt::VisitBottomUp(BasicBlock *BB,
+ DenseMap<const BasicBlock *, BBState> &BBStates,
+ BlotMapVector<Value *, RRInfo> &Retains) {
+
+ DEBUG(dbgs() << "\n== ObjCARCOpt::VisitBottomUp ==\n");
+
bool NestingDetected = false;
BBState &MyStates = BBStates[BB];
}
}
- // If ARC Annotations are enabled, output the current state of pointers at the
- // bottom of the basic block.
- ANNOTATE_BOTTOMUP_BBEND(MyStates, BB);
-
// Visit all the instructions, bottom-up.
for (BasicBlock::iterator I = BB->end(), E = BB->begin(); I != E; --I) {
- Instruction *Inst = llvm::prior(I);
+ Instruction *Inst = std::prev(I);
// Invoke instructions are visited as part of their successors (below).
if (isa<InvokeInst>(Inst))
continue;
- DEBUG(dbgs() << "ObjCARCOpt::VisitButtonUp: Visiting " << *Inst << "\n");
+ DEBUG(dbgs() << "Visiting " << *Inst << "\n");
NestingDetected |= VisitInstructionBottomUp(Inst, BB, Retains, MyStates);
}
NestingDetected |= VisitInstructionBottomUp(II, BB, Retains, MyStates);
}
- // If ARC Annotations are enabled, output the current state of pointers at the
- // top of the basic block.
- ANNOTATE_BOTTOMUP_BBSTART(MyStates, BB);
-
return NestingDetected;
}
DenseMap<Value *, RRInfo> &Releases,
BBState &MyStates) {
bool NestingDetected = false;
- InstructionClass Class = GetInstructionClass(Inst);
- const Value *Arg = 0;
+ ARCInstKind Class = GetARCInstKind(Inst);
+ const Value *Arg = nullptr;
switch (Class) {
- case IC_RetainBlock:
+ case ARCInstKind::RetainBlock:
// 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);
+ case ARCInstKind::Retain:
+ case ARCInstKind::RetainRV: {
+ Arg = GetArgRCIdentityRoot(Inst);
- PtrState &S = MyStates.getPtrTopDownState(Arg);
+ TopDownPtrState &S = MyStates.getPtrTopDownState(Arg);
- // Don't do retain+release tracking for IC_RetainRV, because it's
+ // Don't do retain+release tracking for ARCInstKind::RetainRV, because
+ // it's
// better to let it remain as the first instruction after a call.
- if (Class != IC_RetainRV) {
+ if (Class != ARCInstKind::RetainRV) {
// If we see two retains in a row on the same pointer. If so, make
// a note, and we'll cicle back to revisit it after we've
// hopefully eliminated the second retain, which may allow us to
if (S.GetSeq() == S_Retain)
NestingDetected = true;
- ANNOTATE_TOPDOWN(Inst, Arg, S.GetSeq(), S_Retain);
S.ResetSequenceProgress(S_Retain);
- S.RRI.KnownSafe = S.HasKnownPositiveRefCount();
- S.RRI.Calls.insert(Inst);
+ S.SetKnownSafe(S.HasKnownPositiveRefCount());
+ S.InsertCall(Inst);
}
S.SetKnownPositiveRefCount();
// code below.
break;
}
- case IC_Release: {
- Arg = GetObjCArg(Inst);
+ case ARCInstKind::Release: {
+ Arg = GetArgRCIdentityRoot(Inst);
- PtrState &S = MyStates.getPtrTopDownState(Arg);
+ TopDownPtrState &S = MyStates.getPtrTopDownState(Arg);
S.ClearKnownPositiveRefCount();
- switch (S.GetSeq()) {
+ Sequence OldSeq = S.GetSeq();
+
+ MDNode *ReleaseMetadata =
+ Inst->getMetadata(MDKindCache.ImpreciseReleaseMDKind);
+
+ switch (OldSeq) {
case S_Retain:
case S_CanRelease:
- S.RRI.ReverseInsertPts.clear();
+ if (OldSeq == S_Retain || ReleaseMetadata != nullptr)
+ S.ClearReverseInsertPts();
// FALL THROUGH
case S_Use:
- 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.SetReleaseMetadata(ReleaseMetadata);
+ S.SetTailCallRelease(cast<CallInst>(Inst)->isTailCall());
+ Releases[Inst] = S.GetRRInfo();
S.ClearSequenceProgress();
break;
case S_None:
}
break;
}
- case IC_AutoreleasepoolPop:
+ case ARCInstKind::AutoreleasepoolPop:
// Conservatively, clear MyStates for all known pointers.
MyStates.clearTopDownPointers();
return NestingDetected;
- case IC_AutoreleasepoolPush:
- case IC_None:
+ case ARCInstKind::AutoreleasepoolPush:
+ case ARCInstKind::None:
// These are irrelevant.
return NestingDetected;
default:
// Consider any other possible effects of this instruction on each
// pointer being tracked.
- for (BBState::ptr_iterator MI = MyStates.top_down_ptr_begin(),
- ME = MyStates.top_down_ptr_end(); MI != ME; ++MI) {
+ for (auto MI = MyStates.top_down_ptr_begin(),
+ ME = MyStates.top_down_ptr_end();
+ MI != ME; ++MI) {
const Value *Ptr = MI->first;
if (Ptr == Arg)
continue; // Handled above.
- PtrState &S = MI->second;
+ TopDownPtrState &S = MI->second;
Sequence Seq = S.GetSeq();
// Check for possible releases.
if (CanAlterRefCount(Inst, Ptr, PA, Class)) {
+ DEBUG(dbgs() << "CanAlterRefCount: Seq: " << Seq << "; " << *Ptr
+ << "\n");
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);
+ assert(!S.HasReverseInsertPts());
+ S.InsertReverseInsertPt(Inst);
// One call can't cause a transition from S_Retain to S_CanRelease
// and S_CanRelease to S_Use. If we've made the first transition,
switch (Seq) {
case S_CanRelease:
if (CanUse(Inst, Ptr, PA, Class)) {
+ DEBUG(dbgs() << "CanUse: Seq: " << Seq << "; " << *Ptr
+ << "\n");
S.SetSeq(S_Use);
- ANNOTATE_TOPDOWN(Inst, Ptr, Seq, S_Use);
}
break;
case S_Retain:
ObjCARCOpt::VisitTopDown(BasicBlock *BB,
DenseMap<const BasicBlock *, BBState> &BBStates,
DenseMap<Value *, RRInfo> &Releases) {
+ DEBUG(dbgs() << "\n== ObjCARCOpt::VisitTopDown ==\n");
bool NestingDetected = false;
BBState &MyStates = BBStates[BB];
}
}
- // If ARC Annotations are enabled, output the current state of pointers at the
- // top of the basic block.
- ANNOTATE_TOPDOWN_BBSTART(MyStates, BB);
-
// Visit all the instructions, top-down.
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
Instruction *Inst = I;
- DEBUG(dbgs() << "ObjCARCOpt::VisitTopDown: Visiting " << *Inst << "\n");
+ DEBUG(dbgs() << "Visiting " << *Inst << "\n");
NestingDetected |= VisitInstructionTopDown(Inst, Releases, MyStates);
}
-
- // If ARC Annotations are enabled, output the current state of pointers at the
- // bottom of the basic block.
- ANNOTATE_TOPDOWN_BBEND(MyStates, BB);
-
+
CheckForCFGHazards(BB, BBStates, MyStates);
return NestingDetected;
}
while (SuccStack.back().second != SE) {
BasicBlock *SuccBB = *SuccStack.back().second++;
- if (Visited.insert(SuccBB)) {
+ if (Visited.insert(SuccBB).second) {
TerminatorInst *TI = cast<TerminatorInst>(&SuccBB->back());
SuccStack.push_back(std::make_pair(SuccBB, succ_iterator(TI)));
BBStates[CurrBB].addSucc(SuccBB);
BBState::edge_iterator PE = BBStates[PredStack.back().first].pred_end();
while (PredStack.back().second != PE) {
BasicBlock *BB = *PredStack.back().second++;
- if (Visited.insert(BB)) {
+ if (Visited.insert(BB).second) {
PredStack.push_back(std::make_pair(BB, BBStates[BB].pred_begin()));
goto reverse_dfs_next_succ;
}
}
// Visit the function both top-down and bottom-up.
-bool
-ObjCARCOpt::Visit(Function &F,
- DenseMap<const BasicBlock *, BBState> &BBStates,
- MapVector<Value *, RRInfo> &Retains,
- DenseMap<Value *, RRInfo> &Releases) {
+bool ObjCARCOpt::Visit(Function &F,
+ DenseMap<const BasicBlock *, BBState> &BBStates,
+ BlotMapVector<Value *, RRInfo> &Retains,
+ DenseMap<Value *, RRInfo> &Releases) {
// Use reverse-postorder traversals, because we magically know that loops
// will be well behaved, i.e. they won't repeatedly call retain on a single
SmallVector<BasicBlock *, 16> PostOrder;
SmallVector<BasicBlock *, 16> ReverseCFGPostOrder;
ComputePostOrders(F, PostOrder, ReverseCFGPostOrder,
- NoObjCARCExceptionsMDKind,
- BBStates);
+ MDKindCache.NoObjCARCExceptionsMDKind, BBStates);
// Use reverse-postorder on the reverse CFG for bottom-up.
bool BottomUpNestingDetected = false;
}
/// Move the calls in RetainsToMove and ReleasesToMove.
-void ObjCARCOpt::MoveCalls(Value *Arg,
- RRInfo &RetainsToMove,
+void ObjCARCOpt::MoveCalls(Value *Arg, RRInfo &RetainsToMove,
RRInfo &ReleasesToMove,
- MapVector<Value *, RRInfo> &Retains,
+ BlotMapVector<Value *, RRInfo> &Retains,
DenseMap<Value *, RRInfo> &Releases,
SmallVectorImpl<Instruction *> &DeadInsts,
Module *M) {
Type *ArgTy = Arg->getType();
Type *ParamTy = PointerType::getUnqual(Type::getInt8Ty(ArgTy->getContext()));
+ DEBUG(dbgs() << "== ObjCARCOpt::MoveCalls ==\n");
+
// Insert the new retain and release calls.
- for (SmallPtrSet<Instruction *, 2>::const_iterator
- PI = ReleasesToMove.ReverseInsertPts.begin(),
- PE = ReleasesToMove.ReverseInsertPts.end(); PI != PE; ++PI) {
- Instruction *InsertPt = *PI;
+ for (Instruction *InsertPt : ReleasesToMove.ReverseInsertPts) {
Value *MyArg = ArgTy == ParamTy ? Arg :
new BitCastInst(Arg, ParamTy, "", InsertPt);
- CallInst *Call =
- CallInst::Create(getRetainCallee(M), MyArg, "", InsertPt);
+ Constant *Decl = EP.get(ARCRuntimeEntryPoints::EPT_Retain);
+ CallInst *Call = CallInst::Create(Decl, MyArg, "", InsertPt);
Call->setDoesNotThrow();
Call->setTailCall();
- DEBUG(dbgs() << "ObjCARCOpt::MoveCalls: Inserting new Release: " << *Call
- << "\n"
- " At insertion point: " << *InsertPt
- << "\n");
+ DEBUG(dbgs() << "Inserting new Retain: " << *Call << "\n"
+ "At insertion point: " << *InsertPt << "\n");
}
- for (SmallPtrSet<Instruction *, 2>::const_iterator
- PI = RetainsToMove.ReverseInsertPts.begin(),
- PE = RetainsToMove.ReverseInsertPts.end(); PI != PE; ++PI) {
- Instruction *InsertPt = *PI;
+ for (Instruction *InsertPt : RetainsToMove.ReverseInsertPts) {
Value *MyArg = ArgTy == ParamTy ? Arg :
new BitCastInst(Arg, ParamTy, "", InsertPt);
- CallInst *Call = CallInst::Create(getReleaseCallee(M), MyArg,
- "", InsertPt);
+ Constant *Decl = EP.get(ARCRuntimeEntryPoints::EPT_Release);
+ CallInst *Call = CallInst::Create(Decl, MyArg, "", InsertPt);
// Attach a clang.imprecise_release metadata tag, if appropriate.
if (MDNode *M = ReleasesToMove.ReleaseMetadata)
- Call->setMetadata(ImpreciseReleaseMDKind, M);
+ Call->setMetadata(MDKindCache.ImpreciseReleaseMDKind, M);
Call->setDoesNotThrow();
if (ReleasesToMove.IsTailCallRelease)
Call->setTailCall();
- DEBUG(dbgs() << "ObjCARCOpt::MoveCalls: Inserting new Retain: " << *Call
- << "\n"
- " At insertion point: " << *InsertPt
- << "\n");
+ DEBUG(dbgs() << "Inserting new Release: " << *Call << "\n"
+ "At insertion point: " << *InsertPt << "\n");
}
// Delete the original retain and release calls.
- for (SmallPtrSet<Instruction *, 2>::const_iterator
- AI = RetainsToMove.Calls.begin(),
- AE = RetainsToMove.Calls.end(); AI != AE; ++AI) {
- Instruction *OrigRetain = *AI;
+ for (Instruction *OrigRetain : RetainsToMove.Calls) {
Retains.blot(OrigRetain);
DeadInsts.push_back(OrigRetain);
- DEBUG(dbgs() << "ObjCARCOpt::MoveCalls: Deleting retain: " << *OrigRetain <<
- "\n");
+ DEBUG(dbgs() << "Deleting retain: " << *OrigRetain << "\n");
}
- for (SmallPtrSet<Instruction *, 2>::const_iterator
- AI = ReleasesToMove.Calls.begin(),
- AE = ReleasesToMove.Calls.end(); AI != AE; ++AI) {
- Instruction *OrigRelease = *AI;
+ for (Instruction *OrigRelease : ReleasesToMove.Calls) {
Releases.erase(OrigRelease);
DeadInsts.push_back(OrigRelease);
- DEBUG(dbgs() << "ObjCARCOpt::MoveCalls: Deleting release: " << *OrigRelease
- << "\n");
+ DEBUG(dbgs() << "Deleting release: " << *OrigRelease << "\n");
}
+
}
-bool
-ObjCARCOpt::ConnectTDBUTraversals(DenseMap<const BasicBlock *, BBState>
- &BBStates,
- MapVector<Value *, RRInfo> &Retains,
- DenseMap<Value *, RRInfo> &Releases,
- Module *M,
- SmallVector<Instruction *, 4> &NewRetains,
- SmallVector<Instruction *, 4> &NewReleases,
- SmallVector<Instruction *, 8> &DeadInsts,
- RRInfo &RetainsToMove,
- RRInfo &ReleasesToMove,
- Value *Arg,
- bool KnownSafe,
- bool &AnyPairsCompletelyEliminated) {
+bool ObjCARCOpt::ConnectTDBUTraversals(
+ DenseMap<const BasicBlock *, BBState> &BBStates,
+ BlotMapVector<Value *, RRInfo> &Retains,
+ DenseMap<Value *, RRInfo> &Releases, Module *M,
+ SmallVectorImpl<Instruction *> &NewRetains,
+ SmallVectorImpl<Instruction *> &NewReleases,
+ SmallVectorImpl<Instruction *> &DeadInsts, RRInfo &RetainsToMove,
+ RRInfo &ReleasesToMove, Value *Arg, bool KnownSafe,
+ bool &AnyPairsCompletelyEliminated) {
// If a pair happens in a region where it is known that the reference count
- // is already incremented, we can similarly ignore possible decrements.
+ // is already incremented, we can similarly ignore possible decrements unless
+ // we are dealing with a retainable object with multiple provenance sources.
bool KnownSafeTD = true, KnownSafeBU = true;
+ bool MultipleOwners = false;
+ bool CFGHazardAfflicted = false;
// Connect the dots between the top-down-collected RetainsToMove and
// bottom-up-collected ReleasesToMove to form sets of related calls.
for (SmallVectorImpl<Instruction *>::const_iterator
NI = NewRetains.begin(), NE = NewRetains.end(); NI != NE; ++NI) {
Instruction *NewRetain = *NI;
- MapVector<Value *, RRInfo>::const_iterator It = Retains.find(NewRetain);
+ BlotMapVector<Value *, RRInfo>::const_iterator It =
+ Retains.find(NewRetain);
assert(It != Retains.end());
const RRInfo &NewRetainRRI = It->second;
KnownSafeTD &= NewRetainRRI.KnownSafe;
- for (SmallPtrSet<Instruction *, 2>::const_iterator
- LI = NewRetainRRI.Calls.begin(),
- LE = NewRetainRRI.Calls.end(); LI != LE; ++LI) {
- Instruction *NewRetainRelease = *LI;
+ MultipleOwners =
+ MultipleOwners || MultiOwnersSet.count(GetArgRCIdentityRoot(NewRetain));
+ for (Instruction *NewRetainRelease : NewRetainRRI.Calls) {
DenseMap<Value *, RRInfo>::const_iterator Jt =
Releases.find(NewRetainRelease);
if (Jt == Releases.end())
return false;
const RRInfo &NewRetainReleaseRRI = Jt->second;
- assert(NewRetainReleaseRRI.Calls.count(NewRetain));
- if (ReleasesToMove.Calls.insert(NewRetainRelease)) {
- OldDelta -=
- BBStates[NewRetainRelease->getParent()].GetAllPathCount();
+
+ // If the release does not have a reference to the retain as well,
+ // something happened which is unaccounted for. Do not do anything.
+ //
+ // This can happen if we catch an additive overflow during path count
+ // merging.
+ if (!NewRetainReleaseRRI.Calls.count(NewRetain))
+ return false;
+
+ if (ReleasesToMove.Calls.insert(NewRetainRelease).second) {
+
+ // If we overflow when we compute the path count, don't remove/move
+ // anything.
+ const BBState &NRRBBState = BBStates[NewRetainRelease->getParent()];
+ unsigned PathCount = BBState::OverflowOccurredValue;
+ if (NRRBBState.GetAllPathCountWithOverflow(PathCount))
+ return false;
+ assert(PathCount != BBState::OverflowOccurredValue &&
+ "PathCount at this point can not be "
+ "OverflowOccurredValue.");
+ OldDelta -= PathCount;
// Merge the ReleaseMetadata and IsTailCallRelease values.
if (FirstRelease) {
} else {
if (ReleasesToMove.ReleaseMetadata !=
NewRetainReleaseRRI.ReleaseMetadata)
- ReleasesToMove.ReleaseMetadata = 0;
+ ReleasesToMove.ReleaseMetadata = nullptr;
if (ReleasesToMove.IsTailCallRelease !=
NewRetainReleaseRRI.IsTailCallRelease)
ReleasesToMove.IsTailCallRelease = false;
// Collect the optimal insertion points.
if (!KnownSafe)
- for (SmallPtrSet<Instruction *, 2>::const_iterator
- RI = NewRetainReleaseRRI.ReverseInsertPts.begin(),
- RE = NewRetainReleaseRRI.ReverseInsertPts.end();
- RI != RE; ++RI) {
- Instruction *RIP = *RI;
- if (ReleasesToMove.ReverseInsertPts.insert(RIP))
- NewDelta -= BBStates[RIP->getParent()].GetAllPathCount();
+ for (Instruction *RIP : NewRetainReleaseRRI.ReverseInsertPts) {
+ if (ReleasesToMove.ReverseInsertPts.insert(RIP).second) {
+ // If we overflow when we compute the path count, don't
+ // remove/move anything.
+ const BBState &RIPBBState = BBStates[RIP->getParent()];
+ PathCount = BBState::OverflowOccurredValue;
+ if (RIPBBState.GetAllPathCountWithOverflow(PathCount))
+ return false;
+ assert(PathCount != BBState::OverflowOccurredValue &&
+ "PathCount at this point can not be "
+ "OverflowOccurredValue.");
+ NewDelta -= PathCount;
+ }
}
NewReleases.push_back(NewRetainRelease);
}
assert(It != Releases.end());
const RRInfo &NewReleaseRRI = It->second;
KnownSafeBU &= NewReleaseRRI.KnownSafe;
- for (SmallPtrSet<Instruction *, 2>::const_iterator
- LI = NewReleaseRRI.Calls.begin(),
- LE = NewReleaseRRI.Calls.end(); LI != LE; ++LI) {
- Instruction *NewReleaseRetain = *LI;
- MapVector<Value *, RRInfo>::const_iterator Jt =
- Retains.find(NewReleaseRetain);
+ CFGHazardAfflicted |= NewReleaseRRI.CFGHazardAfflicted;
+ for (Instruction *NewReleaseRetain : NewReleaseRRI.Calls) {
+ BlotMapVector<Value *, RRInfo>::const_iterator Jt =
+ Retains.find(NewReleaseRetain);
if (Jt == Retains.end())
return false;
const RRInfo &NewReleaseRetainRRI = Jt->second;
- assert(NewReleaseRetainRRI.Calls.count(NewRelease));
- if (RetainsToMove.Calls.insert(NewReleaseRetain)) {
- unsigned PathCount =
- BBStates[NewReleaseRetain->getParent()].GetAllPathCount();
+
+ // If the retain does not have a reference to the release as well,
+ // something happened which is unaccounted for. Do not do anything.
+ //
+ // This can happen if we catch an additive overflow during path count
+ // merging.
+ if (!NewReleaseRetainRRI.Calls.count(NewRelease))
+ return false;
+
+ if (RetainsToMove.Calls.insert(NewReleaseRetain).second) {
+ // If we overflow when we compute the path count, don't remove/move
+ // anything.
+ const BBState &NRRBBState = BBStates[NewReleaseRetain->getParent()];
+ unsigned PathCount = BBState::OverflowOccurredValue;
+ if (NRRBBState.GetAllPathCountWithOverflow(PathCount))
+ return false;
+ assert(PathCount != BBState::OverflowOccurredValue &&
+ "PathCount at this point can not be "
+ "OverflowOccurredValue.");
OldDelta += PathCount;
OldCount += PathCount;
// Collect the optimal insertion points.
if (!KnownSafe)
- for (SmallPtrSet<Instruction *, 2>::const_iterator
- RI = NewReleaseRetainRRI.ReverseInsertPts.begin(),
- RE = NewReleaseRetainRRI.ReverseInsertPts.end();
- RI != RE; ++RI) {
- Instruction *RIP = *RI;
- if (RetainsToMove.ReverseInsertPts.insert(RIP)) {
- PathCount = BBStates[RIP->getParent()].GetAllPathCount();
+ for (Instruction *RIP : NewReleaseRetainRRI.ReverseInsertPts) {
+ if (RetainsToMove.ReverseInsertPts.insert(RIP).second) {
+ // If we overflow when we compute the path count, don't
+ // remove/move anything.
+ const BBState &RIPBBState = BBStates[RIP->getParent()];
+
+ PathCount = BBState::OverflowOccurredValue;
+ if (RIPBBState.GetAllPathCountWithOverflow(PathCount))
+ return false;
+ assert(PathCount != BBState::OverflowOccurredValue &&
+ "PathCount at this point can not be "
+ "OverflowOccurredValue.");
NewDelta += PathCount;
NewCount += PathCount;
}
if (NewRetains.empty()) break;
}
- // If the pointer is known incremented or nested, we can safely delete the
- // pair regardless of what's between them.
- if (KnownSafeTD || KnownSafeBU) {
+ // If the pointer is known incremented in 1 direction and we do not have
+ // MultipleOwners, we can safely remove the retain/releases. Otherwise we need
+ // to be known safe in both directions.
+ bool UnconditionallySafe = (KnownSafeTD && KnownSafeBU) ||
+ ((KnownSafeTD || KnownSafeBU) && !MultipleOwners);
+ if (UnconditionallySafe) {
RetainsToMove.ReverseInsertPts.clear();
ReleasesToMove.ReverseInsertPts.clear();
NewCount = 0;
// less aggressive solution which is.
if (NewDelta != 0)
return false;
+
+ // At this point, we are not going to remove any RR pairs, but we still are
+ // able to move RR pairs. If one of our pointers is afflicted with
+ // CFGHazards, we cannot perform such code motion so exit early.
+ const bool WillPerformCodeMotion = RetainsToMove.ReverseInsertPts.size() ||
+ ReleasesToMove.ReverseInsertPts.size();
+ if (CFGHazardAfflicted && WillPerformCodeMotion)
+ return false;
}
// Determine whether the original call points are balanced in the retain and
/// Identify pairings between the retains and releases, and delete and/or move
/// them.
-bool
-ObjCARCOpt::PerformCodePlacement(DenseMap<const BasicBlock *, BBState>
- &BBStates,
- MapVector<Value *, RRInfo> &Retains,
- DenseMap<Value *, RRInfo> &Releases,
- Module *M) {
+bool ObjCARCOpt::PerformCodePlacement(
+ DenseMap<const BasicBlock *, BBState> &BBStates,
+ BlotMapVector<Value *, RRInfo> &Retains,
+ DenseMap<Value *, RRInfo> &Releases, Module *M) {
+ DEBUG(dbgs() << "\n== ObjCARCOpt::PerformCodePlacement ==\n");
+
bool AnyPairsCompletelyEliminated = false;
RRInfo RetainsToMove;
RRInfo ReleasesToMove;
SmallVector<Instruction *, 8> DeadInsts;
// Visit each retain.
- for (MapVector<Value *, RRInfo>::const_iterator I = Retains.begin(),
- E = Retains.end(); I != E; ++I) {
+ for (BlotMapVector<Value *, RRInfo>::const_iterator I = Retains.begin(),
+ E = Retains.end();
+ I != E; ++I) {
Value *V = I->first;
if (!V) continue; // blotted
Instruction *Retain = cast<Instruction>(V);
- DEBUG(dbgs() << "ObjCARCOpt::PerformCodePlacement: Visiting: " << *Retain
- << "\n");
+ DEBUG(dbgs() << "Visiting: " << *Retain << "\n");
- Value *Arg = GetObjCArg(Retain);
+ Value *Arg = GetArgRCIdentityRoot(Retain);
// If the object being released is in static or stack storage, we know it's
// not being managed by ObjC reference counting, so we can delete pairs
if (const LoadInst *LI = dyn_cast<LoadInst>(Arg))
if (const GlobalVariable *GV =
dyn_cast<GlobalVariable>(
- StripPointerCastsAndObjCCalls(LI->getPointerOperand())))
+ GetRCIdentityRoot(LI->getPointerOperand())))
if (GV->isConstant())
KnownSafe = true;
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!
/// Weak pointer optimizations.
void ObjCARCOpt::OptimizeWeakCalls(Function &F) {
+ DEBUG(dbgs() << "\n== ObjCARCOpt::OptimizeWeakCalls ==\n");
+
// First, do memdep-style RLE and S2L optimizations. We can't use memdep
// itself because it uses AliasAnalysis and we need to do provenance
// queries instead.
for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ) {
Instruction *Inst = &*I++;
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeWeakCalls: Visiting: " << *Inst <<
- "\n");
+ DEBUG(dbgs() << "Visiting: " << *Inst << "\n");
- InstructionClass Class = GetBasicInstructionClass(Inst);
- if (Class != IC_LoadWeak && Class != IC_LoadWeakRetained)
+ ARCInstKind Class = GetBasicARCInstKind(Inst);
+ if (Class != ARCInstKind::LoadWeak &&
+ Class != ARCInstKind::LoadWeakRetained)
continue;
// Delete objc_loadWeak calls with no users.
- if (Class == IC_LoadWeak && Inst->use_empty()) {
+ if (Class == ARCInstKind::LoadWeak && Inst->use_empty()) {
Inst->eraseFromParent();
continue;
}
// within the same block. Theoretically, we could do memdep-style non-local
// analysis too, but that would want caching. A better approach would be to
// use the technique that EarlyCSE uses.
- inst_iterator Current = llvm::prior(I);
+ inst_iterator Current = std::prev(I);
BasicBlock *CurrentBB = Current.getBasicBlockIterator();
for (BasicBlock::iterator B = CurrentBB->begin(),
J = Current.getInstructionIterator();
J != B; --J) {
- Instruction *EarlierInst = &*llvm::prior(J);
- InstructionClass EarlierClass = GetInstructionClass(EarlierInst);
+ Instruction *EarlierInst = &*std::prev(J);
+ ARCInstKind EarlierClass = GetARCInstKind(EarlierInst);
switch (EarlierClass) {
- case IC_LoadWeak:
- case IC_LoadWeakRetained: {
+ case ARCInstKind::LoadWeak:
+ case ARCInstKind::LoadWeakRetained: {
// If this is loading from the same pointer, replace this load's value
// with that one.
CallInst *Call = cast<CallInst>(Inst);
case AliasAnalysis::MustAlias:
Changed = true;
// If the load has a builtin retain, insert a plain retain for it.
- if (Class == IC_LoadWeakRetained) {
- CallInst *CI =
- CallInst::Create(getRetainCallee(F.getParent()), EarlierCall,
- "", Call);
+ if (Class == ARCInstKind::LoadWeakRetained) {
+ Constant *Decl = EP.get(ARCRuntimeEntryPoints::EPT_Retain);
+ CallInst *CI = CallInst::Create(Decl, EarlierCall, "", Call);
CI->setTailCall();
}
// Zap the fully redundant load.
}
break;
}
- case IC_StoreWeak:
- case IC_InitWeak: {
+ case ARCInstKind::StoreWeak:
+ case ARCInstKind::InitWeak: {
// If this is storing to the same pointer and has the same size etc.
// replace this load's value with the stored value.
CallInst *Call = cast<CallInst>(Inst);
case AliasAnalysis::MustAlias:
Changed = true;
// If the load has a builtin retain, insert a plain retain for it.
- if (Class == IC_LoadWeakRetained) {
- CallInst *CI =
- CallInst::Create(getRetainCallee(F.getParent()), EarlierCall,
- "", Call);
+ if (Class == ARCInstKind::LoadWeakRetained) {
+ Constant *Decl = EP.get(ARCRuntimeEntryPoints::EPT_Retain);
+ CallInst *CI = CallInst::Create(Decl, EarlierCall, "", Call);
CI->setTailCall();
}
// Zap the fully redundant load.
}
break;
}
- case IC_MoveWeak:
- case IC_CopyWeak:
+ case ARCInstKind::MoveWeak:
+ case ARCInstKind::CopyWeak:
// TOOD: Grab the copied value.
goto clobbered;
- case IC_AutoreleasepoolPush:
- case IC_None:
- case IC_IntrinsicUser:
- case IC_User:
+ case ARCInstKind::AutoreleasepoolPush:
+ case ARCInstKind::None:
+ case ARCInstKind::IntrinsicUser:
+ case ARCInstKind::User:
// Weak pointers are only modified through the weak entry points
// (and arbitrary calls, which could call the weak entry points).
break;
// the alloca and all its users can be zapped.
for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ) {
Instruction *Inst = &*I++;
- InstructionClass Class = GetBasicInstructionClass(Inst);
- if (Class != IC_DestroyWeak)
+ ARCInstKind Class = GetBasicARCInstKind(Inst);
+ if (Class != ARCInstKind::DestroyWeak)
continue;
CallInst *Call = cast<CallInst>(Inst);
Value *Arg = Call->getArgOperand(0);
if (AllocaInst *Alloca = dyn_cast<AllocaInst>(Arg)) {
- for (Value::use_iterator UI = Alloca->use_begin(),
- UE = Alloca->use_end(); UI != UE; ++UI) {
- const Instruction *UserInst = cast<Instruction>(*UI);
- switch (GetBasicInstructionClass(UserInst)) {
- case IC_InitWeak:
- case IC_StoreWeak:
- case IC_DestroyWeak:
+ for (User *U : Alloca->users()) {
+ const Instruction *UserInst = cast<Instruction>(U);
+ switch (GetBasicARCInstKind(UserInst)) {
+ case ARCInstKind::InitWeak:
+ case ARCInstKind::StoreWeak:
+ case ARCInstKind::DestroyWeak:
continue;
default:
goto done;
}
}
Changed = true;
- for (Value::use_iterator UI = Alloca->use_begin(),
- UE = Alloca->use_end(); UI != UE; ) {
+ for (auto UI = Alloca->user_begin(), UE = Alloca->user_end(); UI != UE;) {
CallInst *UserInst = cast<CallInst>(*UI++);
- switch (GetBasicInstructionClass(UserInst)) {
- case IC_InitWeak:
- case IC_StoreWeak:
+ switch (GetBasicARCInstKind(UserInst)) {
+ case ARCInstKind::InitWeak:
+ case ARCInstKind::StoreWeak:
// These functions return their second argument.
UserInst->replaceAllUsesWith(UserInst->getArgOperand(1));
break;
- case IC_DestroyWeak:
+ case ARCInstKind::DestroyWeak:
// No return value.
break;
default:
done:;
}
}
-
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeWeakCalls: Finished List.\n\n");
-
}
/// Identify program paths which execute sequences of retains and releases which
/// can be eliminated.
bool ObjCARCOpt::OptimizeSequences(Function &F) {
- /// Releases, Retains - These are used to store the results of the main flow
- /// analysis. These use Value* as the key instead of Instruction* so that the
- /// map stays valid when we get around to rewriting code and calls get
- /// replaced by arguments.
+ // Releases, Retains - These are used to store the results of the main flow
+ // analysis. These use Value* as the key instead of Instruction* so that the
+ // map stays valid when we get around to rewriting code and calls get
+ // replaced by arguments.
DenseMap<Value *, RRInfo> Releases;
- MapVector<Value *, RRInfo> Retains;
+ BlotMapVector<Value *, RRInfo> Retains;
- /// This is used during the traversal of the function to track the
- /// states for each identified object at each block.
+ // This is used during the traversal of the function to track the
+ // states for each identified object at each block.
DenseMap<const BasicBlock *, BBState> BBStates;
// Analyze the CFG of the function, and all instructions.
bool NestingDetected = Visit(F, BBStates, Retains, Releases);
// Transform.
- return PerformCodePlacement(BBStates, Retains, Releases, F.getParent()) &&
- NestingDetected;
+ bool AnyPairsCompletelyEliminated = PerformCodePlacement(BBStates, Retains,
+ Releases,
+ F.getParent());
+
+ // Cleanup.
+ MultiOwnersSet.clear();
+
+ return AnyPairsCompletelyEliminated && NestingDetected;
+}
+
+/// Check if there is a dependent call earlier that does not have anything in
+/// between the Retain and the call that can affect the reference count of their
+/// shared pointer argument. Note that Retain need not be in BB.
+static bool
+HasSafePathToPredecessorCall(const Value *Arg, Instruction *Retain,
+ SmallPtrSetImpl<Instruction *> &DepInsts,
+ SmallPtrSetImpl<const BasicBlock *> &Visited,
+ ProvenanceAnalysis &PA) {
+ FindDependencies(CanChangeRetainCount, Arg, Retain->getParent(), Retain,
+ DepInsts, Visited, PA);
+ if (DepInsts.size() != 1)
+ return false;
+
+ auto *Call = dyn_cast_or_null<CallInst>(*DepInsts.begin());
+
+ // Check that the pointer is the return value of the call.
+ if (!Call || Arg != Call)
+ return false;
+
+ // Check that the call is a regular call.
+ ARCInstKind Class = GetBasicARCInstKind(Call);
+ if (Class != ARCInstKind::CallOrUser && Class != ARCInstKind::Call)
+ return false;
+
+ return true;
+}
+
+/// Find a dependent retain that precedes the given autorelease for which there
+/// is nothing in between the two instructions that can affect the ref count of
+/// Arg.
+static CallInst *
+FindPredecessorRetainWithSafePath(const Value *Arg, BasicBlock *BB,
+ Instruction *Autorelease,
+ SmallPtrSetImpl<Instruction *> &DepInsts,
+ SmallPtrSetImpl<const BasicBlock *> &Visited,
+ ProvenanceAnalysis &PA) {
+ FindDependencies(CanChangeRetainCount, Arg,
+ BB, Autorelease, DepInsts, Visited, PA);
+ if (DepInsts.size() != 1)
+ return nullptr;
+
+ auto *Retain = dyn_cast_or_null<CallInst>(*DepInsts.begin());
+
+ // Check that we found a retain with the same argument.
+ if (!Retain || !IsRetain(GetBasicARCInstKind(Retain)) ||
+ GetArgRCIdentityRoot(Retain) != Arg) {
+ return nullptr;
+ }
+
+ return Retain;
+}
+
+/// Look for an ``autorelease'' instruction dependent on Arg such that there are
+/// no instructions dependent on Arg that need a positive ref count in between
+/// the autorelease and the ret.
+static CallInst *
+FindPredecessorAutoreleaseWithSafePath(const Value *Arg, BasicBlock *BB,
+ ReturnInst *Ret,
+ SmallPtrSetImpl<Instruction *> &DepInsts,
+ SmallPtrSetImpl<const BasicBlock *> &V,
+ ProvenanceAnalysis &PA) {
+ FindDependencies(NeedsPositiveRetainCount, Arg,
+ BB, Ret, DepInsts, V, PA);
+ if (DepInsts.size() != 1)
+ return nullptr;
+
+ auto *Autorelease = dyn_cast_or_null<CallInst>(*DepInsts.begin());
+ if (!Autorelease)
+ return nullptr;
+ ARCInstKind AutoreleaseClass = GetBasicARCInstKind(Autorelease);
+ if (!IsAutorelease(AutoreleaseClass))
+ return nullptr;
+ if (GetArgRCIdentityRoot(Autorelease) != Arg)
+ return nullptr;
+
+ return Autorelease;
}
/// Look for this pattern:
/// ret i8* %3
/// \endcode
/// And delete the retain and autorelease.
-///
-/// Otherwise if it's just this:
-/// \code
-/// %3 = call i8* @objc_autorelease(i8* %2)
-/// ret i8* %3
-/// \endcode
-/// convert the autorelease to autoreleaseRV.
void ObjCARCOpt::OptimizeReturns(Function &F) {
if (!F.getReturnType()->isPointerTy())
return;
+ DEBUG(dbgs() << "\n== ObjCARCOpt::OptimizeReturns ==\n");
+
SmallPtrSet<Instruction *, 4> DependingInstructions;
SmallPtrSet<const BasicBlock *, 4> Visited;
for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) {
BasicBlock *BB = FI;
ReturnInst *Ret = dyn_cast<ReturnInst>(&BB->back());
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeReturns: Visiting: " << *Ret << "\n");
-
- if (!Ret) continue;
-
- const Value *Arg = StripPointerCastsAndObjCCalls(Ret->getOperand(0));
- FindDependencies(NeedsPositiveRetainCount, Arg,
- BB, Ret, DependingInstructions, Visited, PA);
- if (DependingInstructions.size() != 1)
- goto next_block;
-
- {
- CallInst *Autorelease =
- dyn_cast_or_null<CallInst>(*DependingInstructions.begin());
- if (!Autorelease)
- goto next_block;
- InstructionClass AutoreleaseClass = GetBasicInstructionClass(Autorelease);
- if (!IsAutorelease(AutoreleaseClass))
- goto next_block;
- if (GetObjCArg(Autorelease) != Arg)
- goto next_block;
-
- DependingInstructions.clear();
- Visited.clear();
-
- // Check that there is nothing that can affect the reference
- // count between the autorelease and the retain.
- FindDependencies(CanChangeRetainCount, Arg,
- BB, Autorelease, DependingInstructions, Visited, PA);
- if (DependingInstructions.size() != 1)
- goto next_block;
-
- {
- CallInst *Retain =
- dyn_cast_or_null<CallInst>(*DependingInstructions.begin());
-
- // Check that we found a retain with the same argument.
- if (!Retain ||
- !IsRetain(GetBasicInstructionClass(Retain)) ||
- GetObjCArg(Retain) != Arg)
- goto next_block;
-
- DependingInstructions.clear();
- Visited.clear();
-
- // Check that there is nothing that can affect the reference
- // count between the retain and the call.
- // Note that Retain need not be in BB.
- FindDependencies(CanChangeRetainCount, Arg, Retain->getParent(), Retain,
- DependingInstructions, Visited, PA);
- if (DependingInstructions.size() != 1)
- goto next_block;
-
- {
- CallInst *Call =
- dyn_cast_or_null<CallInst>(*DependingInstructions.begin());
-
- // Check that the pointer is the return value of the call.
- if (!Call || Arg != Call)
- goto next_block;
-
- // Check that the call is a regular call.
- InstructionClass Class = GetBasicInstructionClass(Call);
- if (Class != IC_CallOrUser && Class != IC_Call)
- goto next_block;
-
- // If so, we can zap the retain and autorelease.
- Changed = true;
- ++NumRets;
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeReturns: Erasing: " << *Retain
- << "\n Erasing: "
- << *Autorelease << "\n");
- EraseInstruction(Retain);
- EraseInstruction(Autorelease);
- }
- }
- }
+ DEBUG(dbgs() << "Visiting: " << *Ret << "\n");
+
+ if (!Ret)
+ continue;
+
+ const Value *Arg = GetRCIdentityRoot(Ret->getOperand(0));
+
+ // Look for an ``autorelease'' instruction that is a predecessor of Ret and
+ // dependent on Arg such that there are no instructions dependent on Arg
+ // that need a positive ref count in between the autorelease and Ret.
+ CallInst *Autorelease =
+ FindPredecessorAutoreleaseWithSafePath(Arg, BB, Ret,
+ DependingInstructions, Visited,
+ PA);
+ DependingInstructions.clear();
+ Visited.clear();
+
+ if (!Autorelease)
+ continue;
- next_block:
+ CallInst *Retain =
+ FindPredecessorRetainWithSafePath(Arg, BB, Autorelease,
+ DependingInstructions, Visited, PA);
DependingInstructions.clear();
Visited.clear();
+
+ if (!Retain)
+ continue;
+
+ // Check that there is nothing that can affect the reference count
+ // between the retain and the call. Note that Retain need not be in BB.
+ bool HasSafePathToCall = HasSafePathToPredecessorCall(Arg, Retain,
+ DependingInstructions,
+ Visited, PA);
+ DependingInstructions.clear();
+ Visited.clear();
+
+ if (!HasSafePathToCall)
+ continue;
+
+ // If so, we can zap the retain and autorelease.
+ Changed = true;
+ ++NumRets;
+ DEBUG(dbgs() << "Erasing: " << *Retain << "\nErasing: "
+ << *Autorelease << "\n");
+ EraseInstruction(Retain);
+ EraseInstruction(Autorelease);
}
+}
- DEBUG(dbgs() << "ObjCARCOpt::OptimizeReturns: Finished List.\n\n");
+#ifndef NDEBUG
+void
+ObjCARCOpt::GatherStatistics(Function &F, bool AfterOptimization) {
+ llvm::Statistic &NumRetains =
+ AfterOptimization? NumRetainsAfterOpt : NumRetainsBeforeOpt;
+ llvm::Statistic &NumReleases =
+ AfterOptimization? NumReleasesAfterOpt : NumReleasesBeforeOpt;
+ for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ) {
+ Instruction *Inst = &*I++;
+ switch (GetBasicARCInstKind(Inst)) {
+ default:
+ break;
+ case ARCInstKind::Retain:
+ ++NumRetains;
+ break;
+ case ARCInstKind::Release:
+ ++NumReleases;
+ break;
+ }
+ }
}
+#endif
bool ObjCARCOpt::doInitialization(Module &M) {
if (!EnableARCOpts)
return false;
// Identify the imprecise release metadata kind.
- ImpreciseReleaseMDKind =
- M.getContext().getMDKindID("clang.imprecise_release");
- CopyOnEscapeMDKind =
- 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
+ MDKindCache.ImpreciseReleaseMDKind =
+ M.getContext().getMDKindID("clang.imprecise_release");
+ MDKindCache.CopyOnEscapeMDKind =
+ M.getContext().getMDKindID("clang.arc.copy_on_escape");
+ MDKindCache.NoObjCARCExceptionsMDKind =
+ M.getContext().getMDKindID("clang.arc.no_objc_arc_exceptions");
// Intuitively, objc_retain and others are nocapture, however in practice
// they are not, because they return their argument value. And objc_release
// calls finalizers which can have arbitrary side effects.
- // These are initialized lazily.
- RetainRVCallee = 0;
- AutoreleaseRVCallee = 0;
- ReleaseCallee = 0;
- RetainCallee = 0;
- RetainBlockCallee = 0;
- AutoreleaseCallee = 0;
+ // Initialize our runtime entry point cache.
+ EP.Initialize(&M);
return false;
}
Changed = false;
- DEBUG(dbgs() << "ObjCARCOpt: Visiting Function: " << F.getName() << "\n");
+ DEBUG(dbgs() << "<<< ObjCARCOpt: Visiting Function: " << F.getName() << " >>>"
+ "\n");
PA.setAA(&getAnalysis<AliasAnalysis>());
+#ifndef NDEBUG
+ if (AreStatisticsEnabled()) {
+ GatherStatistics(F, false);
+ }
+#endif
+
// This pass performs several distinct transformations. As a compile-time aid
// when compiling code that isn't ObjC, skip these if the relevant ObjC
// library functions aren't declared.
- // Preliminary optimizations. This also computs UsedInThisFunction.
+ // Preliminary optimizations. This also computes UsedInThisFunction.
OptimizeIndividualCalls(F);
// Optimizations for weak pointers.
- if (UsedInThisFunction & ((1 << IC_LoadWeak) |
- (1 << IC_LoadWeakRetained) |
- (1 << IC_StoreWeak) |
- (1 << IC_InitWeak) |
- (1 << IC_CopyWeak) |
- (1 << IC_MoveWeak) |
- (1 << IC_DestroyWeak)))
+ if (UsedInThisFunction & ((1 << unsigned(ARCInstKind::LoadWeak)) |
+ (1 << unsigned(ARCInstKind::LoadWeakRetained)) |
+ (1 << unsigned(ARCInstKind::StoreWeak)) |
+ (1 << unsigned(ARCInstKind::InitWeak)) |
+ (1 << unsigned(ARCInstKind::CopyWeak)) |
+ (1 << unsigned(ARCInstKind::MoveWeak)) |
+ (1 << unsigned(ARCInstKind::DestroyWeak))))
OptimizeWeakCalls(F);
// Optimizations for retain+release pairs.
- if (UsedInThisFunction & ((1 << IC_Retain) |
- (1 << IC_RetainRV) |
- (1 << IC_RetainBlock)))
- if (UsedInThisFunction & (1 << IC_Release))
+ if (UsedInThisFunction & ((1 << unsigned(ARCInstKind::Retain)) |
+ (1 << unsigned(ARCInstKind::RetainRV)) |
+ (1 << unsigned(ARCInstKind::RetainBlock))))
+ if (UsedInThisFunction & (1 << unsigned(ARCInstKind::Release)))
// Run OptimizeSequences until it either stops making changes or
// no retain+release pair nesting is detected.
while (OptimizeSequences(F)) {}
// Optimizations if objc_autorelease is used.
- if (UsedInThisFunction & ((1 << IC_Autorelease) |
- (1 << IC_AutoreleaseRV)))
+ if (UsedInThisFunction & ((1 << unsigned(ARCInstKind::Autorelease)) |
+ (1 << unsigned(ARCInstKind::AutoreleaseRV))))
OptimizeReturns(F);
+ // Gather statistics after optimization.
+#ifndef NDEBUG
+ if (AreStatisticsEnabled()) {
+ GatherStatistics(F, true);
+ }
+#endif
+
DEBUG(dbgs() << "\n");
return Changed;
projects / oota-llvm.git / blobdiff