X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FADT%2FSmallVector.h;h=769b7dc9f5e8b6e9ca1ec7fb3bf6890e96904fc5;hb=bc363931085587bac42a40653962a3e5acd1ffce;hp=d5fef4828e612e58150d85a79c3971359da2722e;hpb=d0dfbe096dd71ca4d652784705584876f8b18250;p=oota-llvm.git

diff --git a/include/llvm/ADT/SmallVector.h b/include/llvm/ADT/SmallVector.h
index d5fef4828e6..769b7dc9f5e 100644
--- a/include/llvm/ADT/SmallVector.h
+++ b/include/llvm/ADT/SmallVector.h
@@ -14,105 +14,108 @@
 #ifndef LLVM_ADT_SMALLVECTOR_H
 #define LLVM_ADT_SMALLVECTOR_H
 
-#include "llvm/ADT/iterator.h"
+#include "llvm/Support/AlignOf.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/type_traits.h"
 #include <algorithm>
 #include <cassert>
+#include <cstddef>
+#include <cstdlib>
 #include <cstring>
+#include <iterator>
 #include <memory>
 
-#ifdef _MSC_VER
-namespace std {
-#if _MSC_VER <= 1310
-  // Work around flawed VC++ implementation of std::uninitialized_copy.  Define
-  // additional overloads so that elements with pointer types are recognized as
-  // scalars and not objects, causing bizarre type conversion errors.
-  template<class T1, class T2>
-  inline _Scalar_ptr_iterator_tag _Ptr_cat(T1 **, T2 **) {
-    _Scalar_ptr_iterator_tag _Cat;
-    return _Cat;
+namespace llvm {
+
+/// SmallVectorBase - This is all the non-templated stuff common to all
+/// SmallVectors.
+class SmallVectorBase {
+protected:
+  void *BeginX, *EndX, *CapacityX;
+
+protected:
+  SmallVectorBase(void *FirstEl, size_t Size)
+    : BeginX(FirstEl), EndX(FirstEl), CapacityX((char*)FirstEl+Size) {}
+
+  /// grow_pod - This is an implementation of the grow() method which only works
+  /// on POD-like data types and is out of line to reduce code duplication.
+  void grow_pod(void *FirstEl, size_t MinSizeInBytes, size_t TSize);
+
+public:
+  /// size_in_bytes - This returns size()*sizeof(T).
+  size_t size_in_bytes() const {
+    return size_t((char*)EndX - (char*)BeginX);
   }
 
-  template<class T1, class T2>
-  inline _Scalar_ptr_iterator_tag _Ptr_cat(T1* const *, T2 **) {
-    _Scalar_ptr_iterator_tag _Cat;
-    return _Cat;
+  /// capacity_in_bytes - This returns capacity()*sizeof(T).
+  size_t capacity_in_bytes() const {
+    return size_t((char*)CapacityX - (char*)BeginX);
   }
-#else
-// FIXME: It is not clear if the problem is fixed in VS 2005.  What is clear
-// is that the above hack won't work if it wasn't fixed.
-#endif
-}
-#endif
 
-namespace llvm {
+  bool empty() const { return BeginX == EndX; }
+};
 
-/// SmallVectorImpl - This class consists of common code factored out of the
-/// SmallVector class to reduce code duplication based on the SmallVector 'N'
-/// template parameter.
-template <typename T>
-class SmallVectorImpl {
-protected:
-  T *Begin, *End, *Capacity;
+template <typename T, unsigned N> struct SmallVectorStorage;
+
+/// SmallVectorTemplateCommon - This is the part of SmallVectorTemplateBase
+/// which does not depend on whether the type T is a POD. The extra dummy
+/// template argument is used by ArrayRef to avoid unnecessarily requiring T
+/// to be complete.
+template <typename T, typename = void>
+class SmallVectorTemplateCommon : public SmallVectorBase {
+private:
+  template <typename, unsigned> friend struct SmallVectorStorage;
 
   // Allocate raw space for N elements of type T.  If T has a ctor or dtor, we
   // don't want it to be automatically run, so we need to represent the space as
-  // something else.  An array of char would work great, but might not be
-  // aligned sufficiently.  Instead, we either use GCC extensions, or some
-  // number of union instances for the space, which guarantee maximal alignment.
-protected:
-#ifdef __GNUC__
-  typedef char U;
-  U FirstEl __attribute__((aligned));
-#else
-  union U {
-    double D;
-    long double LD;
-    long long L;
-    void *P;
-  } FirstEl;
-#endif
+  // something else.  Use an array of char of sufficient alignment.
+  typedef llvm::AlignedCharArrayUnion<T> U;
+  U FirstEl;
   // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
-public:
-  // Default ctor - Initialize to empty.
-  explicit SmallVectorImpl(unsigned N)
-    : Begin(reinterpret_cast<T*>(&FirstEl)),
-      End(reinterpret_cast<T*>(&FirstEl)),
-      Capacity(reinterpret_cast<T*>(&FirstEl)+N) {
+
+protected:
+  SmallVectorTemplateCommon(size_t Size) : SmallVectorBase(&FirstEl, Size) {}
+
+  void grow_pod(size_t MinSizeInBytes, size_t TSize) {
+    SmallVectorBase::grow_pod(&FirstEl, MinSizeInBytes, TSize);
   }
 
-  ~SmallVectorImpl() {
-    // Destroy the constructed elements in the vector.
-    destroy_range(Begin, End);
+  /// isSmall - Return true if this is a smallvector which has not had dynamic
+  /// memory allocated for it.
+  bool isSmall() const {
+    return BeginX == static_cast<const void*>(&FirstEl);
+  }
 
-    // If this wasn't grown from the inline copy, deallocate the old space.
-    if (!isSmall())
-      operator delete(Begin);
+  /// resetToSmall - Put this vector in a state of being small.
+  void resetToSmall() {
+    BeginX = EndX = CapacityX = &FirstEl;
   }
 
+  void setEnd(T *P) { this->EndX = P; }
+public:
   typedef size_t size_type;
   typedef ptrdiff_t difference_type;
   typedef T value_type;
-  typedef T* iterator;
-  typedef const T* const_iterator;
+  typedef T *iterator;
+  typedef const T *const_iterator;
 
-  typedef std::reverse_iterator<const_iterator>  const_reverse_iterator;
-  typedef std::reverse_iterator<iterator>  reverse_iterator;
+  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+  typedef std::reverse_iterator<iterator> reverse_iterator;
 
-  typedef T& reference;
-  typedef const T& const_reference;
-  typedef T* pointer;
-  typedef const T* const_pointer;
-
-  bool empty() const { return Begin == End; }
-  size_type size() const { return End-Begin; }
-  size_type max_size() const { return size_type(-1) / sizeof(T); }
+  typedef T &reference;
+  typedef const T &const_reference;
+  typedef T *pointer;
+  typedef const T *const_pointer;
 
   // forward iterator creation methods.
-  iterator begin() { return Begin; }
-  const_iterator begin() const { return Begin; }
-  iterator end() { return End; }
-  const_iterator end() const { return End; }
+  iterator begin() { return (iterator)this->BeginX; }
+  const_iterator begin() const { return (const_iterator)this->BeginX; }
+  iterator end() { return (iterator)this->EndX; }
+  const_iterator end() const { return (const_iterator)this->EndX; }
+protected:
+  iterator capacity_ptr() { return (iterator)this->CapacityX; }
+  const_iterator capacity_ptr() const { return (const_iterator)this->CapacityX;}
+public:
 
   // reverse iterator creation methods.
   reverse_iterator rbegin()            { return reverse_iterator(end()); }
@@ -120,16 +123,25 @@ public:
   reverse_iterator rend()              { return reverse_iterator(begin()); }
   const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
 
+  size_type size() const { return end()-begin(); }
+  size_type max_size() const { return size_type(-1) / sizeof(T); }
+
+  /// capacity - Return the total number of elements in the currently allocated
+  /// buffer.
+  size_t capacity() const { return capacity_ptr() - begin(); }
+
+  /// data - Return a pointer to the vector's buffer, even if empty().
+  pointer data() { return pointer(begin()); }
+  /// data - Return a pointer to the vector's buffer, even if empty().
+  const_pointer data() const { return const_pointer(begin()); }
 
-  /* These asserts could be "Begin + idx < End", but there are lots of places
-     in llvm where we use &v[v.size()] instead of v.end(). */
   reference operator[](unsigned idx) {
-    assert (Begin + idx <= End);
-    return Begin[idx];
+    assert(begin() + idx < end());
+    return begin()[idx];
   }
   const_reference operator[](unsigned idx) const {
-    assert (Begin + idx <= End);
-    return Begin[idx];
+    assert(begin() + idx < end());
+    return begin()[idx];
   }
 
   reference front() {
@@ -145,61 +157,278 @@ public:
   const_reference back() const {
     return end()[-1];
   }
+};
+
+/// SmallVectorTemplateBase<isPodLike = false> - This is where we put method
+/// implementations that are designed to work with non-POD-like T's.
+template <typename T, bool isPodLike>
+class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
+protected:
+  SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
 
-  void push_back(const_reference Elt) {
-    if (End < Capacity) {
-  Retry:
-      new (End) T(Elt);
-      ++End;
+  static void destroy_range(T *S, T *E) {
+    while (S != E) {
+      --E;
+      E->~T();
+    }
+  }
+
+  /// move - Use move-assignment to move the range [I, E) onto the
+  /// objects starting with "Dest".  This is just <memory>'s
+  /// std::move, but not all stdlibs actually provide that.
+  template<typename It1, typename It2>
+  static It2 move(It1 I, It1 E, It2 Dest) {
+#if LLVM_USE_RVALUE_REFERENCES
+    for (; I != E; ++I, ++Dest)
+      *Dest = ::std::move(*I);
+    return Dest;
+#else
+    return ::std::copy(I, E, Dest);
+#endif
+  }
+
+  /// move_backward - Use move-assignment to move the range
+  /// [I, E) onto the objects ending at "Dest", moving objects
+  /// in reverse order.  This is just <algorithm>'s
+  /// std::move_backward, but not all stdlibs actually provide that.
+  template<typename It1, typename It2>
+  static It2 move_backward(It1 I, It1 E, It2 Dest) {
+#if LLVM_USE_RVALUE_REFERENCES
+    while (I != E)
+      *--Dest = ::std::move(*--E);
+    return Dest;
+#else
+    return ::std::copy_backward(I, E, Dest);
+#endif
+  }
+
+  /// uninitialized_move - Move the range [I, E) into the uninitialized
+  /// memory starting with "Dest", constructing elements as needed.
+  template<typename It1, typename It2>
+  static void uninitialized_move(It1 I, It1 E, It2 Dest) {
+#if LLVM_USE_RVALUE_REFERENCES
+    for (; I != E; ++I, ++Dest)
+      ::new ((void*) &*Dest) T(::std::move(*I));
+#else
+    ::std::uninitialized_copy(I, E, Dest);
+#endif
+  }
+
+  /// uninitialized_copy - Copy the range [I, E) onto the uninitialized
+  /// memory starting with "Dest", constructing elements as needed.
+  template<typename It1, typename It2>
+  static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
+    std::uninitialized_copy(I, E, Dest);
+  }
+
+  /// grow - Grow the allocated memory (without initializing new
+  /// elements), doubling the size of the allocated memory.
+  /// Guarantees space for at least one more element, or MinSize more
+  /// elements if specified.
+  void grow(size_t MinSize = 0);
+  
+public:
+  void push_back(const T &Elt) {
+    if (this->EndX < this->CapacityX) {
+    Retry:
+      ::new ((void*) this->end()) T(Elt);
+      this->setEnd(this->end()+1);
       return;
     }
-    grow();
+    this->grow();
     goto Retry;
   }
 
+#if LLVM_USE_RVALUE_REFERENCES
+  void push_back(T &&Elt) {
+    if (this->EndX < this->CapacityX) {
+    Retry:
+      ::new ((void*) this->end()) T(::std::move(Elt));
+      this->setEnd(this->end()+1);
+      return;
+    }
+    this->grow();
+    goto Retry;
+  }
+#endif
+  
   void pop_back() {
-    --End;
-    End->~T();
+    this->setEnd(this->end()-1);
+    this->end()->~T();
   }
+};
 
-  T pop_back_val() {
-    T Result = back();
-    pop_back();
-    return Result;
+// Define this out-of-line to dissuade the C++ compiler from inlining it.
+template <typename T, bool isPodLike>
+void SmallVectorTemplateBase<T, isPodLike>::grow(size_t MinSize) {
+  size_t CurCapacity = this->capacity();
+  size_t CurSize = this->size();
+  size_t NewCapacity = 2*CurCapacity + 1; // Always grow, even from zero.
+  if (NewCapacity < MinSize)
+    NewCapacity = MinSize;
+  T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T)));
+
+  // Move the elements over.
+  this->uninitialized_move(this->begin(), this->end(), NewElts);
+
+  // Destroy the original elements.
+  destroy_range(this->begin(), this->end());
+
+  // If this wasn't grown from the inline copy, deallocate the old space.
+  if (!this->isSmall())
+    free(this->begin());
+
+  this->setEnd(NewElts+CurSize);
+  this->BeginX = NewElts;
+  this->CapacityX = this->begin()+NewCapacity;
+}
+
+
+/// SmallVectorTemplateBase<isPodLike = true> - This is where we put method
+/// implementations that are designed to work with POD-like T's.
+template <typename T>
+class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
+protected:
+  SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
+
+  // No need to do a destroy loop for POD's.
+  static void destroy_range(T *, T *) {}
+
+  /// move - Use move-assignment to move the range [I, E) onto the
+  /// objects starting with "Dest".  For PODs, this is just memcpy.
+  template<typename It1, typename It2>
+  static It2 move(It1 I, It1 E, It2 Dest) {
+    return ::std::copy(I, E, Dest);
+  }
+
+  /// move_backward - Use move-assignment to move the range
+  /// [I, E) onto the objects ending at "Dest", moving objects
+  /// in reverse order.
+  template<typename It1, typename It2>
+  static It2 move_backward(It1 I, It1 E, It2 Dest) {
+    return ::std::copy_backward(I, E, Dest);
+  }
+
+  /// uninitialized_move - Move the range [I, E) onto the uninitialized memory
+  /// starting with "Dest", constructing elements into it as needed.
+  template<typename It1, typename It2>
+  static void uninitialized_move(It1 I, It1 E, It2 Dest) {
+    // Just do a copy.
+    uninitialized_copy(I, E, Dest);
+  }
+
+  /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
+  /// starting with "Dest", constructing elements into it as needed.
+  template<typename It1, typename It2>
+  static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
+    // Arbitrary iterator types; just use the basic implementation.
+    std::uninitialized_copy(I, E, Dest);
+  }
+
+  /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
+  /// starting with "Dest", constructing elements into it as needed.
+  template<typename T1, typename T2>
+  static void uninitialized_copy(T1 *I, T1 *E, T2 *Dest) {
+    // Use memcpy for PODs iterated by pointers (which includes SmallVector
+    // iterators): std::uninitialized_copy optimizes to memmove, but we can
+    // use memcpy here.
+    memcpy(Dest, I, (E-I)*sizeof(T));
+  }
+
+  /// grow - double the size of the allocated memory, guaranteeing space for at
+  /// least one more element or MinSize if specified.
+  void grow(size_t MinSize = 0) {
+    this->grow_pod(MinSize*sizeof(T), sizeof(T));
+  }
+public:
+  void push_back(const T &Elt) {
+    if (this->EndX < this->CapacityX) {
+    Retry:
+      memcpy(this->end(), &Elt, sizeof(T));
+      this->setEnd(this->end()+1);
+      return;
+    }
+    this->grow();
+    goto Retry;
+  }
+  
+  void pop_back() {
+    this->setEnd(this->end()-1);
+  }
+};
+
+
+/// SmallVectorImpl - This class consists of common code factored out of the
+/// SmallVector class to reduce code duplication based on the SmallVector 'N'
+/// template parameter.
+template <typename T>
+class SmallVectorImpl : public SmallVectorTemplateBase<T, isPodLike<T>::value> {
+  typedef SmallVectorTemplateBase<T, isPodLike<T>::value > SuperClass;
+
+  SmallVectorImpl(const SmallVectorImpl&); // DISABLED.
+public:
+  typedef typename SuperClass::iterator iterator;
+  typedef typename SuperClass::size_type size_type;
+
+protected:
+  // Default ctor - Initialize to empty.
+  explicit SmallVectorImpl(unsigned N)
+    : SmallVectorTemplateBase<T, isPodLike<T>::value>(N*sizeof(T)) {
+  }
+
+public:
+  ~SmallVectorImpl() {
+    // Destroy the constructed elements in the vector.
+    this->destroy_range(this->begin(), this->end());
+
+    // If this wasn't grown from the inline copy, deallocate the old space.
+    if (!this->isSmall())
+      free(this->begin());
   }
 
+
   void clear() {
-    destroy_range(Begin, End);
-    End = Begin;
+    this->destroy_range(this->begin(), this->end());
+    this->EndX = this->BeginX;
   }
 
   void resize(unsigned N) {
-    if (N < size()) {
-      destroy_range(Begin+N, End);
-      End = Begin+N;
-    } else if (N > size()) {
-      if (unsigned(Capacity-Begin) < N)
-        grow(N);
-      construct_range(End, Begin+N, T());
-      End = Begin+N;
+    if (N < this->size()) {
+      this->destroy_range(this->begin()+N, this->end());
+      this->setEnd(this->begin()+N);
+    } else if (N > this->size()) {
+      if (this->capacity() < N)
+        this->grow(N);
+      std::uninitialized_fill(this->end(), this->begin()+N, T());
+      this->setEnd(this->begin()+N);
     }
   }
 
   void resize(unsigned N, const T &NV) {
-    if (N < size()) {
-      destroy_range(Begin+N, End);
-      End = Begin+N;
-    } else if (N > size()) {
-      if (unsigned(Capacity-Begin) < N)
-        grow(N);
-      construct_range(End, Begin+N, NV);
-      End = Begin+N;
+    if (N < this->size()) {
+      this->destroy_range(this->begin()+N, this->end());
+      this->setEnd(this->begin()+N);
+    } else if (N > this->size()) {
+      if (this->capacity() < N)
+        this->grow(N);
+      std::uninitialized_fill(this->end(), this->begin()+N, NV);
+      this->setEnd(this->begin()+N);
     }
   }
 
   void reserve(unsigned N) {
-    if (unsigned(Capacity-Begin) < N)
-      grow(N);
+    if (this->capacity() < N)
+      this->grow(N);
+  }
+
+  T pop_back_val() {
+#if LLVM_USE_RVALUE_REFERENCES
+    T Result = ::std::move(this->back());
+#else
+    T Result = this->back();
+#endif
+    this->pop_back();
+    return Result;
   }
 
   void swap(SmallVectorImpl &RHS);
@@ -210,99 +439,154 @@ public:
   void append(in_iter in_start, in_iter in_end) {
     size_type NumInputs = std::distance(in_start, in_end);
     // Grow allocated space if needed.
-    if (NumInputs > size_type(Capacity-End))
-      grow(size()+NumInputs);
+    if (NumInputs > size_type(this->capacity_ptr()-this->end()))
+      this->grow(this->size()+NumInputs);
 
     // Copy the new elements over.
-    std::uninitialized_copy(in_start, in_end, End);
-    End += NumInputs;
+    // TODO: NEED To compile time dispatch on whether in_iter is a random access
+    // iterator to use the fast uninitialized_copy.
+    std::uninitialized_copy(in_start, in_end, this->end());
+    this->setEnd(this->end() + NumInputs);
   }
 
   /// append - Add the specified range to the end of the SmallVector.
   ///
   void append(size_type NumInputs, const T &Elt) {
     // Grow allocated space if needed.
-    if (NumInputs > size_type(Capacity-End))
-      grow(size()+NumInputs);
+    if (NumInputs > size_type(this->capacity_ptr()-this->end()))
+      this->grow(this->size()+NumInputs);
 
     // Copy the new elements over.
-    std::uninitialized_fill_n(End, NumInputs, Elt);
-    End += NumInputs;
+    std::uninitialized_fill_n(this->end(), NumInputs, Elt);
+    this->setEnd(this->end() + NumInputs);
   }
 
   void assign(unsigned NumElts, const T &Elt) {
     clear();
-    if (unsigned(Capacity-Begin) < NumElts)
-      grow(NumElts);
-    End = Begin+NumElts;
-    construct_range(Begin, End, Elt);
+    if (this->capacity() < NumElts)
+      this->grow(NumElts);
+    this->setEnd(this->begin()+NumElts);
+    std::uninitialized_fill(this->begin(), this->end(), Elt);
   }
 
   iterator erase(iterator I) {
+    assert(I >= this->begin() && "Iterator to erase is out of bounds.");
+    assert(I < this->end() && "Erasing at past-the-end iterator.");
+
     iterator N = I;
     // Shift all elts down one.
-    std::copy(I+1, End, I);
+    this->move(I+1, this->end(), I);
     // Drop the last elt.
-    pop_back();
+    this->pop_back();
     return(N);
   }
 
   iterator erase(iterator S, iterator E) {
+    assert(S >= this->begin() && "Range to erase is out of bounds.");
+    assert(S <= E && "Trying to erase invalid range.");
+    assert(E <= this->end() && "Trying to erase past the end.");
+
     iterator N = S;
     // Shift all elts down.
-    iterator I = std::copy(E, End, S);
+    iterator I = this->move(E, this->end(), S);
     // Drop the last elts.
-    destroy_range(I, End);
-    End = I;
+    this->destroy_range(I, this->end());
+    this->setEnd(I);
     return(N);
   }
 
+#if LLVM_USE_RVALUE_REFERENCES
+  iterator insert(iterator I, T &&Elt) {
+    if (I == this->end()) {  // Important special case for empty vector.
+      this->push_back(::std::move(Elt));
+      return this->end()-1;
+    }
+
+    assert(I >= this->begin() && "Insertion iterator is out of bounds.");
+    assert(I <= this->end() && "Inserting past the end of the vector.");
+
+    if (this->EndX < this->CapacityX) {
+    Retry:
+      ::new ((void*) this->end()) T(::std::move(this->back()));
+      this->setEnd(this->end()+1);
+      // Push everything else over.
+      this->move_backward(I, this->end()-1, this->end());
+
+      // If we just moved the element we're inserting, be sure to update
+      // the reference.
+      T *EltPtr = &Elt;
+      if (I <= EltPtr && EltPtr < this->EndX)
+        ++EltPtr;
+
+      *I = ::std::move(*EltPtr);
+      return I;
+    }
+    size_t EltNo = I-this->begin();
+    this->grow();
+    I = this->begin()+EltNo;
+    goto Retry;
+  }
+#endif
+
   iterator insert(iterator I, const T &Elt) {
-    if (I == End) {  // Important special case for empty vector.
-      push_back(Elt);
-      return end()-1;
+    if (I == this->end()) {  // Important special case for empty vector.
+      this->push_back(Elt);
+      return this->end()-1;
     }
 
-    if (End < Capacity) {
-  Retry:
-      new (End) T(back());
-      ++End;
+    assert(I >= this->begin() && "Insertion iterator is out of bounds.");
+    assert(I <= this->end() && "Inserting past the end of the vector.");
+
+    if (this->EndX < this->CapacityX) {
+    Retry:
+      ::new ((void*) this->end()) T(this->back());
+      this->setEnd(this->end()+1);
       // Push everything else over.
-      std::copy_backward(I, End-1, End);
-      *I = Elt;
+      this->move_backward(I, this->end()-1, this->end());
+
+      // If we just moved the element we're inserting, be sure to update
+      // the reference.
+      const T *EltPtr = &Elt;
+      if (I <= EltPtr && EltPtr < this->EndX)
+        ++EltPtr;
+
+      *I = *EltPtr;
       return I;
     }
-    size_t EltNo = I-Begin;
-    grow();
-    I = Begin+EltNo;
+    size_t EltNo = I-this->begin();
+    this->grow();
+    I = this->begin()+EltNo;
     goto Retry;
   }
 
   iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
-    if (I == End) {  // Important special case for empty vector.
+    // Convert iterator to elt# to avoid invalidating iterator when we reserve()
+    size_t InsertElt = I - this->begin();
+
+    if (I == this->end()) {  // Important special case for empty vector.
       append(NumToInsert, Elt);
-      return end()-1;
+      return this->begin()+InsertElt;
     }
 
-    // Convert iterator to elt# to avoid invalidating iterator when we reserve()
-    size_t InsertElt = I-begin();
+    assert(I >= this->begin() && "Insertion iterator is out of bounds.");
+    assert(I <= this->end() && "Inserting past the end of the vector.");
 
     // Ensure there is enough space.
-    reserve(static_cast<unsigned>(size() + NumToInsert));
+    reserve(static_cast<unsigned>(this->size() + NumToInsert));
 
     // Uninvalidate the iterator.
-    I = begin()+InsertElt;
+    I = this->begin()+InsertElt;
 
     // If there are more elements between the insertion point and the end of the
     // range than there are being inserted, we can use a simple approach to
     // insertion.  Since we already reserved space, we know that this won't
     // reallocate the vector.
-    if (size_t(end()-I) >= NumToInsert) {
-      T *OldEnd = End;
-      append(End-NumToInsert, End);
+    if (size_t(this->end()-I) >= NumToInsert) {
+      T *OldEnd = this->end();
+      append(this->end()-NumToInsert, this->end());
 
       // Copy the existing elements that get replaced.
-      std::copy(I, OldEnd-NumToInsert, I+NumToInsert);
+      this->move_backward(I, OldEnd-NumToInsert, OldEnd);
 
       std::fill_n(I, NumToInsert, Elt);
       return I;
@@ -311,11 +595,11 @@ public:
     // Otherwise, we're inserting more elements than exist already, and we're
     // not inserting at the end.
 
-    // Copy over the elements that we're about to overwrite.
-    T *OldEnd = End;
-    End += NumToInsert;
+    // Move over the elements that we're about to overwrite.
+    T *OldEnd = this->end();
+    this->setEnd(this->end() + NumToInsert);
     size_t NumOverwritten = OldEnd-I;
-    std::uninitialized_copy(I, OldEnd, End-NumOverwritten);
+    this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
 
     // Replace the overwritten part.
     std::fill_n(I, NumOverwritten, Elt);
@@ -327,31 +611,35 @@ public:
 
   template<typename ItTy>
   iterator insert(iterator I, ItTy From, ItTy To) {
-    if (I == End) {  // Important special case for empty vector.
+    // Convert iterator to elt# to avoid invalidating iterator when we reserve()
+    size_t InsertElt = I - this->begin();
+
+    if (I == this->end()) {  // Important special case for empty vector.
       append(From, To);
-      return end()-1;
+      return this->begin()+InsertElt;
     }
 
+    assert(I >= this->begin() && "Insertion iterator is out of bounds.");
+    assert(I <= this->end() && "Inserting past the end of the vector.");
+
     size_t NumToInsert = std::distance(From, To);
-    // Convert iterator to elt# to avoid invalidating iterator when we reserve()
-    size_t InsertElt = I-begin();
 
     // Ensure there is enough space.
-    reserve(static_cast<unsigned>(size() + NumToInsert));
+    reserve(static_cast<unsigned>(this->size() + NumToInsert));
 
     // Uninvalidate the iterator.
-    I = begin()+InsertElt;
+    I = this->begin()+InsertElt;
 
     // If there are more elements between the insertion point and the end of the
     // range than there are being inserted, we can use a simple approach to
     // insertion.  Since we already reserved space, we know that this won't
     // reallocate the vector.
-    if (size_t(end()-I) >= NumToInsert) {
-      T *OldEnd = End;
-      append(End-NumToInsert, End);
+    if (size_t(this->end()-I) >= NumToInsert) {
+      T *OldEnd = this->end();
+      append(this->end()-NumToInsert, this->end());
 
       // Copy the existing elements that get replaced.
-      std::copy(I, OldEnd-NumToInsert, I+NumToInsert);
+      this->move_backward(I, OldEnd-NumToInsert, OldEnd);
 
       std::copy(From, To, I);
       return I;
@@ -360,175 +648,219 @@ public:
     // Otherwise, we're inserting more elements than exist already, and we're
     // not inserting at the end.
 
-    // Copy over the elements that we're about to overwrite.
-    T *OldEnd = End;
-    End += NumToInsert;
+    // Move over the elements that we're about to overwrite.
+    T *OldEnd = this->end();
+    this->setEnd(this->end() + NumToInsert);
     size_t NumOverwritten = OldEnd-I;
-    std::uninitialized_copy(I, OldEnd, End-NumOverwritten);
+    this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
 
     // Replace the overwritten part.
-    std::copy(From, From+NumOverwritten, I);
+    for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
+      *J = *From;
+      ++J; ++From;
+    }
 
     // Insert the non-overwritten middle part.
-    std::uninitialized_copy(From+NumOverwritten, To, OldEnd);
+    this->uninitialized_copy(From, To, OldEnd);
     return I;
   }
 
-  const SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
+  SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
+
+#if LLVM_USE_RVALUE_REFERENCES
+  SmallVectorImpl &operator=(SmallVectorImpl &&RHS);
+#endif
 
   bool operator==(const SmallVectorImpl &RHS) const {
-    if (size() != RHS.size()) return false;
-    for (T *This = Begin, *That = RHS.Begin, *E = Begin+size();
-         This != E; ++This, ++That)
-      if (*This != *That)
-        return false;
-    return true;
+    if (this->size() != RHS.size()) return false;
+    return std::equal(this->begin(), this->end(), RHS.begin());
+  }
+  bool operator!=(const SmallVectorImpl &RHS) const {
+    return !(*this == RHS);
   }
-  bool operator!=(const SmallVectorImpl &RHS) const { return !(*this == RHS); }
 
   bool operator<(const SmallVectorImpl &RHS) const {
-    return std::lexicographical_compare(begin(), end(),
+    return std::lexicographical_compare(this->begin(), this->end(),
                                         RHS.begin(), RHS.end());
   }
 
-private:
-  /// isSmall - Return true if this is a smallvector which has not had dynamic
-  /// memory allocated for it.
-  bool isSmall() const {
-    return static_cast<const void*>(Begin) ==
-           static_cast<const void*>(&FirstEl);
-  }
-
-  /// grow - double the size of the allocated memory, guaranteeing space for at
-  /// least one more element or MinSize if specified.
-  void grow(size_type MinSize = 0);
-
-  void construct_range(T *S, T *E, const T &Elt) {
-    for (; S != E; ++S)
-      new (S) T(Elt);
-  }
-
-  void destroy_range(T *S, T *E) {
-    while (S != E) {
-      --E;
-      E->~T();
-    }
+  /// set_size - Set the array size to \arg N, which the current array must have
+  /// enough capacity for.
+  ///
+  /// This does not construct or destroy any elements in the vector.
+  ///
+  /// Clients can use this in conjunction with capacity() to write past the end
+  /// of the buffer when they know that more elements are available, and only
+  /// update the size later. This avoids the cost of value initializing elements
+  /// which will only be overwritten.
+  void set_size(unsigned N) {
+    assert(N <= this->capacity());
+    this->setEnd(this->begin() + N);
   }
 };
 
-// Define this out-of-line to dissuade the C++ compiler from inlining it.
-template <typename T>
-void SmallVectorImpl<T>::grow(size_t MinSize) {
-  size_t CurCapacity = Capacity-Begin;
-  size_t CurSize = size();
-  size_t NewCapacity = 2*CurCapacity;
-  if (NewCapacity < MinSize)
-    NewCapacity = MinSize;
-  T *NewElts = static_cast<T*>(operator new(NewCapacity*sizeof(T)));
-
-  // Copy the elements over.
-  if (is_class<T>::value)
-    std::uninitialized_copy(Begin, End, NewElts);
-  else
-    // Use memcpy for PODs (std::uninitialized_copy optimizes to memmove).
-    memcpy(NewElts, Begin, CurSize * sizeof(T));
-
-  // Destroy the original elements.
-  destroy_range(Begin, End);
-
-  // If this wasn't grown from the inline copy, deallocate the old space.
-  if (!isSmall())
-    operator delete(Begin);
-
-  Begin = NewElts;
-  End = NewElts+CurSize;
-  Capacity = Begin+NewCapacity;
-}
 
 template <typename T>
 void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
   if (this == &RHS) return;
 
   // We can only avoid copying elements if neither vector is small.
-  if (!isSmall() && !RHS.isSmall()) {
-    std::swap(Begin, RHS.Begin);
-    std::swap(End, RHS.End);
-    std::swap(Capacity, RHS.Capacity);
+  if (!this->isSmall() && !RHS.isSmall()) {
+    std::swap(this->BeginX, RHS.BeginX);
+    std::swap(this->EndX, RHS.EndX);
+    std::swap(this->CapacityX, RHS.CapacityX);
     return;
   }
-  if (RHS.size() > size_type(Capacity-Begin))
-    grow(RHS.size());
-  if (size() > size_type(RHS.Capacity-RHS.begin()))
-    RHS.grow(size());
+  if (RHS.size() > this->capacity())
+    this->grow(RHS.size());
+  if (this->size() > RHS.capacity())
+    RHS.grow(this->size());
 
   // Swap the shared elements.
-  size_t NumShared = size();
+  size_t NumShared = this->size();
   if (NumShared > RHS.size()) NumShared = RHS.size();
   for (unsigned i = 0; i != static_cast<unsigned>(NumShared); ++i)
-    std::swap(Begin[i], RHS[i]);
+    std::swap((*this)[i], RHS[i]);
 
   // Copy over the extra elts.
-  if (size() > RHS.size()) {
-    size_t EltDiff = size() - RHS.size();
-    std::uninitialized_copy(Begin+NumShared, End, RHS.End);
-    RHS.End += EltDiff;
-    destroy_range(Begin+NumShared, End);
-    End = Begin+NumShared;
-  } else if (RHS.size() > size()) {
-    size_t EltDiff = RHS.size() - size();
-    std::uninitialized_copy(RHS.Begin+NumShared, RHS.End, End);
-    End += EltDiff;
-    destroy_range(RHS.Begin+NumShared, RHS.End);
-    RHS.End = RHS.Begin+NumShared;
+  if (this->size() > RHS.size()) {
+    size_t EltDiff = this->size() - RHS.size();
+    this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
+    RHS.setEnd(RHS.end()+EltDiff);
+    this->destroy_range(this->begin()+NumShared, this->end());
+    this->setEnd(this->begin()+NumShared);
+  } else if (RHS.size() > this->size()) {
+    size_t EltDiff = RHS.size() - this->size();
+    this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
+    this->setEnd(this->end() + EltDiff);
+    this->destroy_range(RHS.begin()+NumShared, RHS.end());
+    RHS.setEnd(RHS.begin()+NumShared);
   }
 }
 
 template <typename T>
-const SmallVectorImpl<T> &
-SmallVectorImpl<T>::operator=(const SmallVectorImpl<T> &RHS) {
+SmallVectorImpl<T> &SmallVectorImpl<T>::
+  operator=(const SmallVectorImpl<T> &RHS) {
   // Avoid self-assignment.
   if (this == &RHS) return *this;
 
   // If we already have sufficient space, assign the common elements, then
   // destroy any excess.
-  unsigned RHSSize = unsigned(RHS.size());
-  unsigned CurSize = unsigned(size());
+  size_t RHSSize = RHS.size();
+  size_t CurSize = this->size();
   if (CurSize >= RHSSize) {
     // Assign common elements.
     iterator NewEnd;
     if (RHSSize)
-      NewEnd = std::copy(RHS.Begin, RHS.Begin+RHSSize, Begin);
+      NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
     else
-      NewEnd = Begin;
+      NewEnd = this->begin();
 
     // Destroy excess elements.
-    destroy_range(NewEnd, End);
+    this->destroy_range(NewEnd, this->end());
 
     // Trim.
-    End = NewEnd;
+    this->setEnd(NewEnd);
     return *this;
   }
 
   // If we have to grow to have enough elements, destroy the current elements.
   // This allows us to avoid copying them during the grow.
-  if (unsigned(Capacity-Begin) < RHSSize) {
+  // FIXME: don't do this if they're efficiently moveable.
+  if (this->capacity() < RHSSize) {
     // Destroy current elements.
-    destroy_range(Begin, End);
-    End = Begin;
+    this->destroy_range(this->begin(), this->end());
+    this->setEnd(this->begin());
     CurSize = 0;
-    grow(RHSSize);
+    this->grow(RHSSize);
   } else if (CurSize) {
     // Otherwise, use assignment for the already-constructed elements.
-    std::copy(RHS.Begin, RHS.Begin+CurSize, Begin);
+    std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
   }
 
   // Copy construct the new elements in place.
-  std::uninitialized_copy(RHS.Begin+CurSize, RHS.End, Begin+CurSize);
+  this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
+                           this->begin()+CurSize);
+
+  // Set end.
+  this->setEnd(this->begin()+RHSSize);
+  return *this;
+}
+
+#if LLVM_USE_RVALUE_REFERENCES
+template <typename T>
+SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
+  // Avoid self-assignment.
+  if (this == &RHS) return *this;
+
+  // If the RHS isn't small, clear this vector and then steal its buffer.
+  if (!RHS.isSmall()) {
+    this->destroy_range(this->begin(), this->end());
+    if (!this->isSmall()) free(this->begin());
+    this->BeginX = RHS.BeginX;
+    this->EndX = RHS.EndX;
+    this->CapacityX = RHS.CapacityX;
+    RHS.resetToSmall();
+    return *this;
+  }
+
+  // If we already have sufficient space, assign the common elements, then
+  // destroy any excess.
+  size_t RHSSize = RHS.size();
+  size_t CurSize = this->size();
+  if (CurSize >= RHSSize) {
+    // Assign common elements.
+    iterator NewEnd = this->begin();
+    if (RHSSize)
+      NewEnd = this->move(RHS.begin(), RHS.end(), NewEnd);
+
+    // Destroy excess elements and trim the bounds.
+    this->destroy_range(NewEnd, this->end());
+    this->setEnd(NewEnd);
+
+    // Clear the RHS.
+    RHS.clear();
+
+    return *this;
+  }
+
+  // If we have to grow to have enough elements, destroy the current elements.
+  // This allows us to avoid copying them during the grow.
+  // FIXME: this may not actually make any sense if we can efficiently move
+  // elements.
+  if (this->capacity() < RHSSize) {
+    // Destroy current elements.
+    this->destroy_range(this->begin(), this->end());
+    this->setEnd(this->begin());
+    CurSize = 0;
+    this->grow(RHSSize);
+  } else if (CurSize) {
+    // Otherwise, use assignment for the already-constructed elements.
+    this->move(RHS.begin(), RHS.end(), this->begin());
+  }
+
+  // Move-construct the new elements in place.
+  this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
+                           this->begin()+CurSize);
 
   // Set end.
-  End = Begin+RHSSize;
+  this->setEnd(this->begin()+RHSSize);
+
+  RHS.clear();
   return *this;
 }
+#endif
+
+/// Storage for the SmallVector elements which aren't contained in
+/// SmallVectorTemplateCommon. There are 'N-1' elements here. The remaining '1'
+/// element is in the base class. This is specialized for the N=1 and N=0 cases
+/// to avoid allocating unnecessary storage.
+template <typename T, unsigned N>
+struct SmallVectorStorage {
+  typename SmallVectorTemplateCommon<T>::U InlineElts[N - 1];
+};
+template <typename T> struct SmallVectorStorage<T, 1> {};
+template <typename T> struct SmallVectorStorage<T, 0> {};
 
 /// SmallVector - This is a 'vector' (really, a variable-sized array), optimized
 /// for the case when the array is small.  It contains some number of elements
@@ -540,43 +872,23 @@ SmallVectorImpl<T>::operator=(const SmallVectorImpl<T> &RHS) {
 ///
 template <typename T, unsigned N>
 class SmallVector : public SmallVectorImpl<T> {
-  /// InlineElts - These are 'N-1' elements that are stored inline in the body
-  /// of the vector.  The extra '1' element is stored in SmallVectorImpl.
-  typedef typename SmallVectorImpl<T>::U U;
-  enum {
-    // MinUs - The number of U's require to cover N T's.
-    MinUs = (static_cast<unsigned int>(sizeof(T))*N +
-             static_cast<unsigned int>(sizeof(U)) - 1) /
-            static_cast<unsigned int>(sizeof(U)),
-
-    // NumInlineEltsElts - The number of elements actually in this array.  There
-    // is already one in the parent class, and we have to round up to avoid
-    // having a zero-element array.
-    NumInlineEltsElts = MinUs > 1 ? (MinUs - 1) : 1,
-
-    // NumTsAvailable - The number of T's we actually have space for, which may
-    // be more than N due to rounding.
-    NumTsAvailable = (NumInlineEltsElts+1)*static_cast<unsigned int>(sizeof(U))/
-                     static_cast<unsigned int>(sizeof(T))
-  };
-  U InlineElts[NumInlineEltsElts];
+  /// Storage - Inline space for elements which aren't stored in the base class.
+  SmallVectorStorage<T, N> Storage;
 public:
-  SmallVector() : SmallVectorImpl<T>(NumTsAvailable) {
+  SmallVector() : SmallVectorImpl<T>(N) {
   }
 
   explicit SmallVector(unsigned Size, const T &Value = T())
-    : SmallVectorImpl<T>(NumTsAvailable) {
-    this->reserve(Size);
-    while (Size--)
-      this->push_back(Value);
+    : SmallVectorImpl<T>(N) {
+    this->assign(Size, Value);
   }
 
   template<typename ItTy>
-  SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(NumTsAvailable) {
+  SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
     this->append(S, E);
   }
 
-  SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(NumTsAvailable) {
+  SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
     if (!RHS.empty())
       SmallVectorImpl<T>::operator=(RHS);
   }
@@ -586,8 +898,25 @@ public:
     return *this;
   }
 
+#if LLVM_USE_RVALUE_REFERENCES
+  SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
+    if (!RHS.empty())
+      SmallVectorImpl<T>::operator=(::std::move(RHS));
+  }
+
+  const SmallVector &operator=(SmallVector &&RHS) {
+    SmallVectorImpl<T>::operator=(::std::move(RHS));
+    return *this;
+  }
+#endif
+
 };
 
+template<typename T, unsigned N>
+static inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
+  return X.capacity_in_bytes();
+}
+
 } // End llvm namespace
 
 namespace std {