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authorDan Gohman <djg@cray.com>2007-07-18 16:29:46 +0000
committerDan Gohman <djg@cray.com>2007-07-18 16:29:46 +0000
commitf17a25c88b892d30c2b41ba7ecdfbdfb2b4be9cc (patch)
treeebb79ea1ee5e3bc1fdf38541a811a8b804f0679a /include/llvm/ADT/SmallVector.h
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It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'include/llvm/ADT/SmallVector.h')
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diff --git a/include/llvm/ADT/SmallVector.h b/include/llvm/ADT/SmallVector.h
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+//===- llvm/ADT/SmallVector.h - 'Normally small' vectors --------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the SmallVector class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ADT_SMALLVECTOR_H
+#define LLVM_ADT_SMALLVECTOR_H
+
+#include <algorithm>
+#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;
+ }
+
+ template<class T1, class T2>
+ inline _Scalar_ptr_iterator_tag _Ptr_cat(T1* const *, T2 **) {
+ _Scalar_ptr_iterator_tag _Cat;
+ return _Cat;
+ }
+#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 {
+
+/// 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;
+
+ // 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
+ // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
+public:
+ // Default ctor - Initialize to empty.
+ SmallVectorImpl(unsigned N)
+ : Begin((T*)&FirstEl), End((T*)&FirstEl), Capacity((T*)&FirstEl+N) {
+ }
+
+ ~SmallVectorImpl() {
+ // Destroy the constructed elements in the vector.
+ destroy_range(Begin, End);
+
+ // If this wasn't grown from the inline copy, deallocate the old space.
+ if (!isSmall())
+ delete[] (char*)Begin;
+ }
+
+ typedef size_t size_type;
+ typedef T* iterator;
+ typedef const T* const_iterator;
+ typedef T& reference;
+ typedef const T& const_reference;
+
+ bool empty() const { return Begin == End; }
+ size_type size() const { return End-Begin; }
+
+ iterator begin() { return Begin; }
+ const_iterator begin() const { return Begin; }
+
+ iterator end() { return End; }
+ const_iterator end() const { return End; }
+
+ reference operator[](unsigned idx) {
+ return Begin[idx];
+ }
+ const_reference operator[](unsigned idx) const {
+ return Begin[idx];
+ }
+
+ reference front() {
+ return begin()[0];
+ }
+ const_reference front() const {
+ return begin()[0];
+ }
+
+ reference back() {
+ return end()[-1];
+ }
+ const_reference back() const {
+ return end()[-1];
+ }
+
+ void push_back(const_reference Elt) {
+ if (End < Capacity) {
+ Retry:
+ new (End) T(Elt);
+ ++End;
+ return;
+ }
+ grow();
+ goto Retry;
+ }
+
+ void pop_back() {
+ --End;
+ End->~T();
+ }
+
+ void clear() {
+ destroy_range(Begin, End);
+ End = Begin;
+ }
+
+ 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;
+ }
+ }
+
+ 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;
+ }
+ }
+
+ void reserve(unsigned N) {
+ if (unsigned(Capacity-Begin) < N)
+ grow(N);
+ }
+
+ void swap(SmallVectorImpl &RHS);
+
+ /// append - Add the specified range to the end of the SmallVector.
+ ///
+ template<typename in_iter>
+ void append(in_iter in_start, in_iter in_end) {
+ unsigned NumInputs = std::distance(in_start, in_end);
+ // Grow allocated space if needed.
+ if (End+NumInputs > Capacity)
+ grow(size()+NumInputs);
+
+ // Copy the new elements over.
+ std::uninitialized_copy(in_start, in_end, End);
+ 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);
+ }
+
+ void erase(iterator I) {
+ // Shift all elts down one.
+ std::copy(I+1, End, I);
+ // Drop the last elt.
+ pop_back();
+ }
+
+ void erase(iterator S, iterator E) {
+ // Shift all elts down.
+ iterator I = std::copy(E, End, S);
+ // Drop the last elts.
+ destroy_range(I, End);
+ End = I;
+ }
+
+ iterator insert(iterator I, const T &Elt) {
+ if (I == End) { // Important special case for empty vector.
+ push_back(Elt);
+ return end()-1;
+ }
+
+ if (End < Capacity) {
+ Retry:
+ new (End) T(back());
+ ++End;
+ // Push everything else over.
+ std::copy_backward(I, End-1, End);
+ *I = Elt;
+ return I;
+ }
+ unsigned EltNo = I-Begin;
+ grow();
+ I = Begin+EltNo;
+ goto Retry;
+ }
+
+ template<typename ItTy>
+ iterator insert(iterator I, ItTy From, ItTy To) {
+ if (I == End) { // Important special case for empty vector.
+ append(From, To);
+ return end()-1;
+ }
+
+ unsigned NumToInsert = std::distance(From, To);
+ // Convert iterator to elt# to avoid invalidating iterator when we reserve()
+ unsigned InsertElt = I-begin();
+
+ // Ensure there is enough space.
+ reserve(size() + NumToInsert);
+
+ // Uninvalidate the iterator.
+ I = begin()+InsertElt;
+
+ // If we already have this many elements in the collection, append the
+ // dest elements at the end, then copy over the appropriate elements. Since
+ // we already reserved space, we know that this won't reallocate the vector.
+ if (size() >= NumToInsert) {
+ T *OldEnd = End;
+ append(End-NumToInsert, End);
+
+ // Copy the existing elements that get replaced.
+ std::copy(I, OldEnd-NumToInsert, I+NumToInsert);
+
+ std::copy(From, To, I);
+ return I;
+ }
+
+ // 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;
+ unsigned NumOverwritten = OldEnd-I;
+ std::uninitialized_copy(I, OldEnd, End-NumOverwritten);
+
+ // Replace the overwritten part.
+ std::copy(From, From+NumOverwritten, I);
+
+ // Insert the non-overwritten middle part.
+ std::uninitialized_copy(From+NumOverwritten, To, OldEnd);
+ return I;
+ }
+
+ const SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
+
+private:
+ /// isSmall - Return true if this is a smallvector which has not had dynamic
+ /// memory allocated for it.
+ bool isSmall() const {
+ return (void*)Begin == (void*)&FirstEl;
+ }
+
+ /// grow - double the size of the allocated memory, guaranteeing space for at
+ /// least one more element or MinSize if specified.
+ void grow(unsigned 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();
+ }
+ }
+};
+
+// Define this out-of-line to dissuade the C++ compiler from inlining it.
+template <typename T>
+void SmallVectorImpl<T>::grow(unsigned MinSize) {
+ unsigned CurCapacity = unsigned(Capacity-Begin);
+ unsigned CurSize = unsigned(size());
+ unsigned NewCapacity = 2*CurCapacity;
+ if (NewCapacity < MinSize)
+ NewCapacity = MinSize;
+ T *NewElts = reinterpret_cast<T*>(new char[NewCapacity*sizeof(T)]);
+
+ // Copy the elements over.
+ std::uninitialized_copy(Begin, End, NewElts);
+
+ // Destroy the original elements.
+ destroy_range(Begin, End);
+
+ // If this wasn't grown from the inline copy, deallocate the old space.
+ if (!isSmall())
+ delete[] (char*)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);
+ return;
+ }
+ if (Begin+RHS.size() > Capacity)
+ grow(RHS.size());
+ if (RHS.begin()+size() > RHS.Capacity)
+ RHS.grow(size());
+
+ // Swap the shared elements.
+ unsigned NumShared = size();
+ if (NumShared > RHS.size()) NumShared = RHS.size();
+ for (unsigned i = 0; i != NumShared; ++i)
+ std::swap(Begin[i], RHS[i]);
+
+ // Copy over the extra elts.
+ if (size() > RHS.size()) {
+ unsigned 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()) {
+ unsigned 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;
+ }
+}
+
+template <typename T>
+const 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());
+ if (CurSize >= RHSSize) {
+ // Assign common elements.
+ iterator NewEnd = std::copy(RHS.Begin, RHS.Begin+RHSSize, Begin);
+
+ // Destroy excess elements.
+ destroy_range(NewEnd, End);
+
+ // Trim.
+ End = 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) {
+ // Destroy current elements.
+ destroy_range(Begin, End);
+ End = Begin;
+ CurSize = 0;
+ grow(RHSSize);
+ } else if (CurSize) {
+ // Otherwise, use assignment for the already-constructed elements.
+ std::copy(RHS.Begin, RHS.Begin+CurSize, Begin);
+ }
+
+ // Copy construct the new elements in place.
+ std::uninitialized_copy(RHS.Begin+CurSize, RHS.End, Begin+CurSize);
+
+ // Set end.
+ End = Begin+RHSSize;
+ return *this;
+}
+
+/// 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
+/// in-place, which allows it to avoid heap allocation when the actual number of
+/// elements is below that threshold. This allows normal "small" cases to be
+/// fast without losing generality for large inputs.
+///
+/// Note that this does not attempt to be exception safe.
+///
+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 = (sizeof(T)*N+sizeof(U)-1)/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) > 0 ? (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)*sizeof(U) / sizeof(T)
+ };
+ U InlineElts[NumInlineEltsElts];
+public:
+ SmallVector() : SmallVectorImpl<T>(NumTsAvailable) {
+ }
+
+ explicit SmallVector(unsigned Size, const T &Value = T())
+ : SmallVectorImpl<T>(NumTsAvailable) {
+ this->reserve(Size);
+ while (Size--)
+ push_back(Value);
+ }
+
+ template<typename ItTy>
+ SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(NumTsAvailable) {
+ append(S, E);
+ }
+
+ SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(NumTsAvailable) {
+ operator=(RHS);
+ }
+
+ const SmallVector &operator=(const SmallVector &RHS) {
+ SmallVectorImpl<T>::operator=(RHS);
+ return *this;
+ }
+};
+
+} // End llvm namespace
+
+namespace std {
+ /// Implement std::swap in terms of SmallVector swap.
+ template<typename T>
+ inline void
+ swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
+ LHS.swap(RHS);
+ }
+
+ /// Implement std::swap in terms of SmallVector swap.
+ template<typename T, unsigned N>
+ inline void
+ swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {
+ LHS.swap(RHS);
+ }
+}
+
+#endif