Import llvm::SmallPtrSet.

include/llvm/DenseMapInfo.h

@@ -14,6 +14,7 @@
 #ifndef LLVM_ADT_DENSEMAPINFO_H
 #define LLVM_ADT_DENSEMAPINFO_H
 
+#include "llvm/PointerLikeTypeTraits.h"
 #include "llvm/type_traits.h"
 
 namespace llvm {
@@ -31,12 +32,12 @@ template<typename T>
 struct DenseMapInfo<T*> {
   static inline T* getEmptyKey() {
     uintptr_t Val = static_cast<uintptr_t>(-1);
-    Val <<= 2;
+    Val <<= PointerLikeTypeTraits<T*>::NumLowBitsAvailable;
     return reinterpret_cast<T*>(Val);
   }
   static inline T* getTombstoneKey() {
     uintptr_t Val = static_cast<uintptr_t>(-2);
-    Val <<= 2;
+    Val <<= PointerLikeTypeTraits<T*>::NumLowBitsAvailable;
     return reinterpret_cast<T*>(Val);
   }
   static unsigned getHashValue(const T *PtrVal) {

include/llvm/PointerLikeTypeTraits.h

@@ -0,0 +1,81 @@
+//===- llvm/Support/PointerLikeTypeTraits.h - Pointer Traits ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the PointerLikeTypeTraits class.  This allows data
+// structures to reason about pointers and other things that are pointer sized.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_POINTERLIKETYPETRAITS_H
+#define LLVM_SUPPORT_POINTERLIKETYPETRAITS_H
+
+#include <cstdint>
+
+namespace llvm {
+  
+/// PointerLikeTypeTraits - This is a traits object that is used to handle
+/// pointer types and things that are just wrappers for pointers as a uniform
+/// entity.
+template <typename T>
+class PointerLikeTypeTraits {
+  // getAsVoidPointer
+  // getFromVoidPointer
+  // getNumLowBitsAvailable
+};
+
+// Provide PointerLikeTypeTraits for non-cvr pointers.
+template<typename T>
+class PointerLikeTypeTraits<T*> {
+public:
+  static inline void *getAsVoidPointer(T* P) { return P; }
+  static inline T *getFromVoidPointer(void *P) {
+    return static_cast<T*>(P);
+  }
+  
+  /// Note, we assume here that malloc returns objects at least 4-byte aligned.
+  /// However, this may be wrong, or pointers may be from something other than
+  /// malloc.  In this case, you should specialize this template to reduce this.
+  ///
+  /// All clients should use assertions to do a run-time check to ensure that
+  /// this is actually true.
+  enum { NumLowBitsAvailable = 2 };
+};
+  
+// Provide PointerLikeTypeTraits for const pointers.
+template<typename T>
+class PointerLikeTypeTraits<const T*> {
+  typedef PointerLikeTypeTraits<T*> NonConst;
+
+public:
+  static inline const void *getAsVoidPointer(const T* P) {
+    return NonConst::getAsVoidPointer(const_cast<T*>(P));
+  }
+  static inline const T *getFromVoidPointer(const void *P) {
+    return NonConst::getFromVoidPointer(const_cast<void*>(P));
+  }
+  enum { NumLowBitsAvailable = NonConst::NumLowBitsAvailable };
+};
+
+// Provide PointerLikeTypeTraits for uintptr_t.
+template<>
+class PointerLikeTypeTraits<uintptr_t> {
+public:
+  static inline void *getAsVoidPointer(uintptr_t P) {
+    return reinterpret_cast<void*>(P);
+  }
+  static inline uintptr_t getFromVoidPointer(void *P) {
+    return reinterpret_cast<uintptr_t>(P);
+  }
+  // No bits are available!
+  enum { NumLowBitsAvailable = 0 };
+};
+  
+} // end namespace llvm
+
+#endif

include/llvm/SmallPtrSet.h

@@ -0,0 +1,346 @@
+//===- llvm/ADT/SmallPtrSet.h - 'Normally small' pointer set ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the SmallPtrSet class.  See the doxygen comment for
+// SmallPtrSetImplBase for more details on the algorithm used.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ADT_SMALLPTRSET_H
+#define LLVM_ADT_SMALLPTRSET_H
+
+#include "llvm/Compiler.h"
+#include "llvm/PointerLikeTypeTraits.h"
+#include <cassert>
+#include <cstddef>
+#include <cstring>
+#include <iterator>
+#include <utility>
+
+namespace llvm {
+
+class SmallPtrSetIteratorImpl;
+
+/// SmallPtrSetImplBase - This is the common code shared among all the
+/// SmallPtrSet<>'s, which is almost everything.  SmallPtrSet has two modes, one
+/// for small and one for large sets.
+///
+/// Small sets use an array of pointers allocated in the SmallPtrSet object,
+/// which is treated as a simple array of pointers.  When a pointer is added to
+/// the set, the array is scanned to see if the element already exists, if not
+/// the element is 'pushed back' onto the array.  If we run out of space in the
+/// array, we grow into the 'large set' case.  SmallSet should be used when the
+/// sets are often small.  In this case, no memory allocation is used, and only
+/// light-weight and cache-efficient scanning is used.
+///
+/// Large sets use a classic exponentially-probed hash table.  Empty buckets are
+/// represented with an illegal pointer value (-1) to allow null pointers to be
+/// inserted.  Tombstones are represented with another illegal pointer value
+/// (-2), to allow deletion.  The hash table is resized when the table is 3/4 or
+/// more.  When this happens, the table is doubled in size.
+///
+class SmallPtrSetImplBase {
+  friend class SmallPtrSetIteratorImpl;
+protected:
+  /// SmallArray - Points to a fixed size set of buckets, used in 'small mode'.
+  const void **SmallArray;
+  /// CurArray - This is the current set of buckets.  If equal to SmallArray,
+  /// then the set is in 'small mode'.
+  const void **CurArray;
+  /// CurArraySize - The allocated size of CurArray, always a power of two.
+  unsigned CurArraySize;
+
+  // If small, this is # elts allocated consecutively
+  unsigned NumElements;
+  unsigned NumTombstones;
+
+  // Helpers to copy and move construct a SmallPtrSet.
+  SmallPtrSetImplBase(const void **SmallStorage, const SmallPtrSetImplBase &that);
+  SmallPtrSetImplBase(const void **SmallStorage, unsigned SmallSize,
+                  SmallPtrSetImplBase &&that);
+  explicit SmallPtrSetImplBase(const void **SmallStorage, unsigned SmallSize) :
+    SmallArray(SmallStorage), CurArray(SmallStorage), CurArraySize(SmallSize) {
+    assert(SmallSize && (SmallSize & (SmallSize-1)) == 0 &&
+           "Initial size must be a power of two!");
+    clear();
+  }
+  ~SmallPtrSetImplBase();
+
+public:
+  typedef unsigned size_type;
+  bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const { return size() == 0; }
+  size_type size() const { return NumElements; }
+
+  void clear() {
+    // If the capacity of the array is huge, and the # elements used is small,
+    // shrink the array.
+    if (!isSmall() && NumElements*4 < CurArraySize && CurArraySize > 32)
+      return shrink_and_clear();
+
+    // Fill the array with empty markers.
+    memset(CurArray, -1, CurArraySize*sizeof(void*));
+    NumElements = 0;
+    NumTombstones = 0;
+  }
+
+protected:
+  static void *getTombstoneMarker() { return reinterpret_cast<void*>(-2); }
+  static void *getEmptyMarker() {
+    // Note that -1 is chosen to make clear() efficiently implementable with
+    // memset and because it's not a valid pointer value.
+    return reinterpret_cast<void*>(-1);
+  }
+
+  /// insert_imp - This returns true if the pointer was new to the set, false if
+  /// it was already in the set.  This is hidden from the client so that the
+  /// derived class can check that the right type of pointer is passed in.
+  std::pair<const void *const *, bool> insert_imp(const void *Ptr);
+
+  /// erase_imp - If the set contains the specified pointer, remove it and
+  /// return true, otherwise return false.  This is hidden from the client so
+  /// that the derived class can check that the right type of pointer is passed
+  /// in.
+  bool erase_imp(const void * Ptr);
+
+  bool count_imp(const void * Ptr) const {
+    if (isSmall()) {
+      // Linear search for the item.
+      for (const void *const *APtr = SmallArray,
+                      *const *E = SmallArray+NumElements; APtr != E; ++APtr)
+        if (*APtr == Ptr)
+          return true;
+      return false;
+    }
+
+    // Big set case.
+    return *FindBucketFor(Ptr) == Ptr;
+  }
+
+private:
+  bool isSmall() const { return CurArray == SmallArray; }
+
+  const void * const *FindBucketFor(const void *Ptr) const;
+  void shrink_and_clear();
+
+  /// Grow - Allocate a larger backing store for the buckets and move it over.
+  void Grow(unsigned NewSize);
+
+  void operator=(const SmallPtrSetImplBase &RHS) = delete;
+protected:
+  /// swap - Swaps the elements of two sets.
+  /// Note: This method assumes that both sets have the same small size.
+  void swap(SmallPtrSetImplBase &RHS);
+
+  void CopyFrom(const SmallPtrSetImplBase &RHS);
+  void MoveFrom(unsigned SmallSize, SmallPtrSetImplBase &&RHS);
+};
+
+/// SmallPtrSetIteratorImpl - This is the common base class shared between all
+/// instances of SmallPtrSetIterator.
+class SmallPtrSetIteratorImpl {
+protected:
+  const void *const *Bucket;
+  const void *const *End;
+public:
+  explicit SmallPtrSetIteratorImpl(const void *const *BP, const void*const *E)
+    : Bucket(BP), End(E) {
+      AdvanceIfNotValid();
+  }
+
+  bool operator==(const SmallPtrSetIteratorImpl &RHS) const {
+    return Bucket == RHS.Bucket;
+  }
+  bool operator!=(const SmallPtrSetIteratorImpl &RHS) const {
+    return Bucket != RHS.Bucket;
+  }
+
+protected:
+  /// AdvanceIfNotValid - If the current bucket isn't valid, advance to a bucket
+  /// that is.   This is guaranteed to stop because the end() bucket is marked
+  /// valid.
+  void AdvanceIfNotValid() {
+    assert(Bucket <= End);
+    while (Bucket != End &&
+           (*Bucket == SmallPtrSetImplBase::getEmptyMarker() ||
+            *Bucket == SmallPtrSetImplBase::getTombstoneMarker()))
+      ++Bucket;
+  }
+};
+
+/// SmallPtrSetIterator - This implements a const_iterator for SmallPtrSet.
+template<typename PtrTy>
+class SmallPtrSetIterator : public SmallPtrSetIteratorImpl {
+  typedef PointerLikeTypeTraits<PtrTy> PtrTraits;
+  
+public:
+  typedef PtrTy                     value_type;
+  typedef PtrTy                     reference;
+  typedef PtrTy                     pointer;
+  typedef std::ptrdiff_t            difference_type;
+  typedef std::forward_iterator_tag iterator_category;
+  
+  explicit SmallPtrSetIterator(const void *const *BP, const void *const *E)
+    : SmallPtrSetIteratorImpl(BP, E) {}
+
+  // Most methods provided by baseclass.
+
+  const PtrTy operator*() const {
+    assert(Bucket < End);
+    return PtrTraits::getFromVoidPointer(const_cast<void*>(*Bucket));
+  }
+
+  inline SmallPtrSetIterator& operator++() {          // Preincrement
+    ++Bucket;
+    AdvanceIfNotValid();
+    return *this;
+  }
+
+  SmallPtrSetIterator operator++(int) {        // Postincrement
+    SmallPtrSetIterator tmp = *this; ++*this; return tmp;
+  }
+};
+
+/// RoundUpToPowerOfTwo - This is a helper template that rounds N up to the next
+/// power of two (which means N itself if N is already a power of two).
+template<unsigned N>
+struct RoundUpToPowerOfTwo;
+
+/// RoundUpToPowerOfTwoH - If N is not a power of two, increase it.  This is a
+/// helper template used to implement RoundUpToPowerOfTwo.
+template<unsigned N, bool isPowerTwo>
+struct RoundUpToPowerOfTwoH {
+  enum { Val = N };
+};
+template<unsigned N>
+struct RoundUpToPowerOfTwoH<N, false> {
+  enum {
+    // We could just use NextVal = N+1, but this converges faster.  N|(N-1) sets
+    // the right-most zero bits to one all at once, e.g. 0b0011000 -> 0b0011111.
+    Val = RoundUpToPowerOfTwo<(N|(N-1)) + 1>::Val
+  };
+};
+
+template<unsigned N>
+struct RoundUpToPowerOfTwo {
+  enum { Val = RoundUpToPowerOfTwoH<N, (N&(N-1)) == 0>::Val };
+};
+  
+
+/// \brief A templated base class for \c SmallPtrSet which provides the
+/// typesafe interface that is common across all small sizes.
+///
+/// This is particularly useful for passing around between interface boundaries
+/// to avoid encoding a particular small size in the interface boundary.
+template <typename PtrType>
+class SmallPtrSetImpl : public SmallPtrSetImplBase {
+  typedef PointerLikeTypeTraits<PtrType> PtrTraits;
+
+  SmallPtrSetImpl(const SmallPtrSetImpl&) = delete;
+protected:
+  // Constructors that forward to the base.
+  SmallPtrSetImpl(const void **SmallStorage, const SmallPtrSetImpl &that)
+      : SmallPtrSetImplBase(SmallStorage, that) {}
+  SmallPtrSetImpl(const void **SmallStorage, unsigned SmallSize,
+                  SmallPtrSetImpl &&that)
+      : SmallPtrSetImplBase(SmallStorage, SmallSize, std::move(that)) {}
+  explicit SmallPtrSetImpl(const void **SmallStorage, unsigned SmallSize)
+      : SmallPtrSetImplBase(SmallStorage, SmallSize) {}
+
+public:
+  typedef SmallPtrSetIterator<PtrType> iterator;
+  typedef SmallPtrSetIterator<PtrType> const_iterator;
+
+  /// Inserts Ptr if and only if there is no element in the container equal to
+  /// Ptr. The bool component of the returned pair is true if and only if the
+  /// insertion takes place, and the iterator component of the pair points to
+  /// the element equal to Ptr.
+  std::pair<iterator, bool> insert(PtrType Ptr) {
+    auto p = insert_imp(PtrTraits::getAsVoidPointer(Ptr));
+    return std::make_pair(iterator(p.first, CurArray + CurArraySize), p.second);
+  }
+
+  /// erase - If the set contains the specified pointer, remove it and return
+  /// true, otherwise return false.
+  bool erase(PtrType Ptr) {
+    return erase_imp(PtrTraits::getAsVoidPointer(Ptr));
+  }
+
+  /// count - Return 1 if the specified pointer is in the set, 0 otherwise.
+  size_type count(PtrType Ptr) const {
+    return count_imp(PtrTraits::getAsVoidPointer(Ptr)) ? 1 : 0;
+  }
+
+  template <typename IterT>
+  void insert(IterT I, IterT E) {
+    for (; I != E; ++I)
+      insert(*I);
+  }
+
+  inline iterator begin() const {
+    return iterator(CurArray, CurArray+CurArraySize);
+  }
+  inline iterator end() const {
+    return iterator(CurArray+CurArraySize, CurArray+CurArraySize);
+  }
+};
+
+/// SmallPtrSet - This class implements a set which is optimized for holding
+/// SmallSize or less elements.  This internally rounds up SmallSize to the next
+/// power of two if it is not already a power of two.  See the comments above
+/// SmallPtrSetImplBase for details of the algorithm.
+template<class PtrType, unsigned SmallSize>
+class SmallPtrSet : public SmallPtrSetImpl<PtrType> {
+  typedef SmallPtrSetImpl<PtrType> BaseT;
+
+  // Make sure that SmallSize is a power of two, round up if not.
+  enum { SmallSizePowTwo = RoundUpToPowerOfTwo<SmallSize>::Val };
+  /// SmallStorage - Fixed size storage used in 'small mode'.
+  const void *SmallStorage[SmallSizePowTwo];
+public:
+  SmallPtrSet() : BaseT(SmallStorage, SmallSizePowTwo) {}
+  SmallPtrSet(const SmallPtrSet &that) : BaseT(SmallStorage, that) {}
+  SmallPtrSet(SmallPtrSet &&that)
+      : BaseT(SmallStorage, SmallSizePowTwo, std::move(that)) {}
+
+  template<typename It>
+  SmallPtrSet(It I, It E) : BaseT(SmallStorage, SmallSizePowTwo) {
+    this->insert(I, E);
+  }
+
+  SmallPtrSet<PtrType, SmallSize> &
+  operator=(const SmallPtrSet<PtrType, SmallSize> &RHS) {
+    if (&RHS != this)
+      this->CopyFrom(RHS);
+    return *this;
+  }
+
+  SmallPtrSet<PtrType, SmallSize>&
+  operator=(SmallPtrSet<PtrType, SmallSize> &&RHS) {
+    if (&RHS != this)
+      this->MoveFrom(SmallSizePowTwo, std::move(RHS));
+    return *this;
+  }
+
+  /// swap - Swaps the elements of two sets.
+  void swap(SmallPtrSet<PtrType, SmallSize> &RHS) {
+    SmallPtrSetImplBase::swap(RHS);
+  }
+};
+
+} // namespace llvm
+
+namespace std {
+  /// Implement std::swap in terms of SmallPtrSet swap.
+  template<class T, unsigned N>
+  inline void swap(llvm::SmallPtrSet<T, N> &LHS, llvm::SmallPtrSet<T, N> &RHS) {
+    LHS.swap(RHS);
+  }
+}
+
+#endif

src/llvm/SmallPtrSet.cpp

@@ -0,0 +1,338 @@
+//===- llvm/ADT/SmallPtrSet.cpp - 'Normally small' pointer set ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the SmallPtrSet class.  See SmallPtrSet.h for an
+// overview of the algorithm.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/SmallPtrSet.h"
+#include "llvm/DenseMapInfo.h"
+#include "llvm/MathExtras.h"
+#include <algorithm>
+#include <cstdlib>
+
+using namespace llvm;
+
+void SmallPtrSetImplBase::shrink_and_clear() {
+  assert(!isSmall() && "Can't shrink a small set!");
+  free(CurArray);
+
+  // Reduce the number of buckets.
+  CurArraySize = NumElements > 16 ? 1 << (Log2_32_Ceil(NumElements) + 1) : 32;
+  NumElements = NumTombstones = 0;
+
+  // Install the new array.  Clear all the buckets to empty.
+  CurArray = (const void**)malloc(sizeof(void*) * CurArraySize);
+  assert(CurArray && "Failed to allocate memory?");
+  memset(CurArray, -1, CurArraySize*sizeof(void*));
+}
+
+std::pair<const void *const *, bool>
+SmallPtrSetImplBase::insert_imp(const void *Ptr) {
+  if (isSmall()) {
+    // Check to see if it is already in the set.
+    for (const void **APtr = SmallArray, **E = SmallArray+NumElements;
+         APtr != E; ++APtr)
+      if (*APtr == Ptr)
+        return std::make_pair(APtr, false);
+
+    // Nope, there isn't.  If we stay small, just 'pushback' now.
+    if (NumElements < CurArraySize) {
+      SmallArray[NumElements++] = Ptr;
+      return std::make_pair(SmallArray + (NumElements - 1), true);
+    }
+    // Otherwise, hit the big set case, which will call grow.
+  }
+
+  if (LLVM_UNLIKELY(NumElements * 4 >= CurArraySize * 3)) {
+    // If more than 3/4 of the array is full, grow.
+    Grow(CurArraySize < 64 ? 128 : CurArraySize*2);
+  } else if (LLVM_UNLIKELY(CurArraySize - (NumElements + NumTombstones) <
+                           CurArraySize / 8)) {
+    // If fewer of 1/8 of the array is empty (meaning that many are filled with
+    // tombstones), rehash.
+    Grow(CurArraySize);
+  }
+  
+  // Okay, we know we have space.  Find a hash bucket.
+  const void **Bucket = const_cast<const void**>(FindBucketFor(Ptr));
+  if (*Bucket == Ptr)
+    return std::make_pair(Bucket, false); // Already inserted, good.
+
+  // Otherwise, insert it!
+  if (*Bucket == getTombstoneMarker())
+    --NumTombstones;
+  *Bucket = Ptr;
+  ++NumElements;  // Track density.
+  return std::make_pair(Bucket, true);
+}
+
+bool SmallPtrSetImplBase::erase_imp(const void * Ptr) {
+  if (isSmall()) {
+    // Check to see if it is in the set.
+    for (const void **APtr = SmallArray, **E = SmallArray+NumElements;
+         APtr != E; ++APtr)
+      if (*APtr == Ptr) {
+        // If it is in the set, replace this element.
+        *APtr = E[-1];
+        E[-1] = getEmptyMarker();
+        --NumElements;
+        return true;
+      }
+    
+    return false;
+  }
+  
+  // Okay, we know we have space.  Find a hash bucket.
+  void **Bucket = const_cast<void**>(FindBucketFor(Ptr));
+  if (*Bucket != Ptr) return false;  // Not in the set?
+
+  // Set this as a tombstone.
+  *Bucket = getTombstoneMarker();
+  --NumElements;
+  ++NumTombstones;
+  return true;
+}
+
+const void * const *SmallPtrSetImplBase::FindBucketFor(const void *Ptr) const {
+  unsigned Bucket = DenseMapInfo<void *>::getHashValue(Ptr) & (CurArraySize-1);
+  unsigned ArraySize = CurArraySize;
+  unsigned ProbeAmt = 1;
+  const void *const *Array = CurArray;
+  const void *const *Tombstone = nullptr;
+  while (1) {
+    // If we found an empty bucket, the pointer doesn't exist in the set.
+    // Return a tombstone if we've seen one so far, or the empty bucket if
+    // not.
+    if (LLVM_LIKELY(Array[Bucket] == getEmptyMarker()))
+      return Tombstone ? Tombstone : Array+Bucket;
+
+    // Found Ptr's bucket?
+    if (LLVM_LIKELY(Array[Bucket] == Ptr))
+      return Array+Bucket;
+
+    // If this is a tombstone, remember it.  If Ptr ends up not in the set, we
+    // prefer to return it than something that would require more probing.
+    if (Array[Bucket] == getTombstoneMarker() && !Tombstone)
+      Tombstone = Array+Bucket;  // Remember the first tombstone found.
+    
+    // It's a hash collision or a tombstone. Reprobe.
+    Bucket = (Bucket + ProbeAmt++) & (ArraySize-1);
+  }
+}
+
+/// Grow - Allocate a larger backing store for the buckets and move it over.
+///
+void SmallPtrSetImplBase::Grow(unsigned NewSize) {
+  // Allocate at twice as many buckets, but at least 128.
+  unsigned OldSize = CurArraySize;
+  
+  const void **OldBuckets = CurArray;
+  bool WasSmall = isSmall();
+  
+  // Install the new array.  Clear all the buckets to empty.
+  CurArray = (const void**)malloc(sizeof(void*) * NewSize);
+  assert(CurArray && "Failed to allocate memory?");
+  CurArraySize = NewSize;
+  memset(CurArray, -1, NewSize*sizeof(void*));
+  
+  // Copy over all the elements.
+  if (WasSmall) {
+    // Small sets store their elements in order.
+    for (const void **BucketPtr = OldBuckets, **E = OldBuckets+NumElements;
+         BucketPtr != E; ++BucketPtr) {
+      const void *Elt = *BucketPtr;
+      *const_cast<void**>(FindBucketFor(Elt)) = const_cast<void*>(Elt);
+    }
+  } else {
+    // Copy over all valid entries.
+    for (const void **BucketPtr = OldBuckets, **E = OldBuckets+OldSize;
+         BucketPtr != E; ++BucketPtr) {
+      // Copy over the element if it is valid.
+      const void *Elt = *BucketPtr;
+      if (Elt != getTombstoneMarker() && Elt != getEmptyMarker())
+        *const_cast<void**>(FindBucketFor(Elt)) = const_cast<void*>(Elt);
+    }
+    
+    free(OldBuckets);
+    NumTombstones = 0;
+  }
+}
+
+SmallPtrSetImplBase::SmallPtrSetImplBase(const void **SmallStorage,
+                                 const SmallPtrSetImplBase& that) {
+  SmallArray = SmallStorage;
+
+  // If we're becoming small, prepare to insert into our stack space
+  if (that.isSmall()) {
+    CurArray = SmallArray;
+  // Otherwise, allocate new heap space (unless we were the same size)
+  } else {
+    CurArray = (const void**)malloc(sizeof(void*) * that.CurArraySize);
+    assert(CurArray && "Failed to allocate memory?");
+  }
+  
+  // Copy over the new array size
+  CurArraySize = that.CurArraySize;
+
+  // Copy over the contents from the other set
+  memcpy(CurArray, that.CurArray, sizeof(void*)*CurArraySize);
+  
+  NumElements = that.NumElements;
+  NumTombstones = that.NumTombstones;
+}
+
+SmallPtrSetImplBase::SmallPtrSetImplBase(const void **SmallStorage,
+                                         unsigned SmallSize,
+                                         SmallPtrSetImplBase &&that) {
+  SmallArray = SmallStorage;
+
+  // Copy over the basic members.
+  CurArraySize = that.CurArraySize;
+  NumElements = that.NumElements;
+  NumTombstones = that.NumTombstones;
+
+  // When small, just copy into our small buffer.
+  if (that.isSmall()) {
+    CurArray = SmallArray;
+    memcpy(CurArray, that.CurArray, sizeof(void *) * CurArraySize);
+  } else {
+    // Otherwise, we steal the large memory allocation and no copy is needed.
+    CurArray = that.CurArray;
+    that.CurArray = that.SmallArray;
+  }
+
+  // Make the "that" object small and empty.
+  that.CurArraySize = SmallSize;
+  assert(that.CurArray == that.SmallArray);
+  that.NumElements = 0;
+  that.NumTombstones = 0;
+}
+
+/// CopyFrom - implement operator= from a smallptrset that has the same pointer
+/// type, but may have a different small size.
+void SmallPtrSetImplBase::CopyFrom(const SmallPtrSetImplBase &RHS) {
+  assert(&RHS != this && "Self-copy should be handled by the caller.");
+
+  if (isSmall() && RHS.isSmall())
+    assert(CurArraySize == RHS.CurArraySize &&
+           "Cannot assign sets with different small sizes");
+
+  // If we're becoming small, prepare to insert into our stack space
+  if (RHS.isSmall()) {
+    if (!isSmall())
+      free(CurArray);
+    CurArray = SmallArray;
+  // Otherwise, allocate new heap space (unless we were the same size)
+  } else if (CurArraySize != RHS.CurArraySize) {
+    if (isSmall())
+      CurArray = (const void**)malloc(sizeof(void*) * RHS.CurArraySize);
+    else {
+      const void **T = (const void**)realloc(CurArray,
+                                             sizeof(void*) * RHS.CurArraySize);
+      if (!T)
+        free(CurArray);
+      CurArray = T;
+    }
+    assert(CurArray && "Failed to allocate memory?");
+  }
+  
+  // Copy over the new array size
+  CurArraySize = RHS.CurArraySize;
+
+  // Copy over the contents from the other set
+  memcpy(CurArray, RHS.CurArray, sizeof(void*)*CurArraySize);
+  
+  NumElements = RHS.NumElements;
+  NumTombstones = RHS.NumTombstones;
+}
+
+void SmallPtrSetImplBase::MoveFrom(unsigned SmallSize,
+                                   SmallPtrSetImplBase &&RHS) {
+  assert(&RHS != this && "Self-move should be handled by the caller.");
+
+  if (!isSmall())
+    free(CurArray);
+
+  if (RHS.isSmall()) {
+    // Copy a small RHS rather than moving.
+    CurArray = SmallArray;
+    memcpy(CurArray, RHS.CurArray, sizeof(void*)*RHS.CurArraySize);
+  } else {
+    CurArray = RHS.CurArray;
+    RHS.CurArray = RHS.SmallArray;
+  }
+
+  // Copy the rest of the trivial members.
+  CurArraySize = RHS.CurArraySize;
+  NumElements = RHS.NumElements;
+  NumTombstones = RHS.NumTombstones;
+
+  // Make the RHS small and empty.
+  RHS.CurArraySize = SmallSize;
+  assert(RHS.CurArray == RHS.SmallArray);
+  RHS.NumElements = 0;
+  RHS.NumTombstones = 0;
+}
+
+void SmallPtrSetImplBase::swap(SmallPtrSetImplBase &RHS) {
+  if (this == &RHS) return;
+
+  // We can only avoid copying elements if neither set is small.
+  if (!this->isSmall() && !RHS.isSmall()) {
+    std::swap(this->CurArray, RHS.CurArray);
+    std::swap(this->CurArraySize, RHS.CurArraySize);
+    std::swap(this->NumElements, RHS.NumElements);
+    std::swap(this->NumTombstones, RHS.NumTombstones);
+    return;
+  }
+
+  // FIXME: From here on we assume that both sets have the same small size.
+
+  // If only RHS is small, copy the small elements into LHS and move the pointer
+  // from LHS to RHS.
+  if (!this->isSmall() && RHS.isSmall()) {
+    std::copy(RHS.SmallArray, RHS.SmallArray+RHS.CurArraySize,
+              this->SmallArray);
+    std::swap(this->NumElements, RHS.NumElements);
+    std::swap(this->CurArraySize, RHS.CurArraySize);
+    RHS.CurArray = this->CurArray;
+    RHS.NumTombstones = this->NumTombstones;
+    this->CurArray = this->SmallArray;
+    this->NumTombstones = 0;
+    return;
+  }
+
+  // If only LHS is small, copy the small elements into RHS and move the pointer
+  // from RHS to LHS.
+  if (this->isSmall() && !RHS.isSmall()) {
+    std::copy(this->SmallArray, this->SmallArray+this->CurArraySize,
+              RHS.SmallArray);
+    std::swap(RHS.NumElements, this->NumElements);
+    std::swap(RHS.CurArraySize, this->CurArraySize);
+    this->CurArray = RHS.CurArray;
+    this->NumTombstones = RHS.NumTombstones;
+    RHS.CurArray = RHS.SmallArray;
+    RHS.NumTombstones = 0;
+    return;
+  }
+
+  // Both a small, just swap the small elements.
+  assert(this->isSmall() && RHS.isSmall());
+  assert(this->CurArraySize == RHS.CurArraySize);
+  std::swap_ranges(this->SmallArray, this->SmallArray+this->CurArraySize,
+                   RHS.SmallArray);
+  std::swap(this->NumElements, RHS.NumElements);
+}
+
+SmallPtrSetImplBase::~SmallPtrSetImplBase() {
+  if (!isSmall())
+    free(CurArray);
+}