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author | Dan Gohman <djg@cray.com> | 2007-07-18 16:29:46 +0000 |
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committer | Dan Gohman <djg@cray.com> | 2007-07-18 16:29:46 +0000 |
commit | f17a25c88b892d30c2b41ba7ecdfbdfb2b4be9cc (patch) | |
tree | ebb79ea1ee5e3bc1fdf38541a811a8b804f0679a /include/llvm/ADT/SmallVector.h | |
download | external_llvm-f17a25c88b892d30c2b41ba7ecdfbdfb2b4be9cc.zip external_llvm-f17a25c88b892d30c2b41ba7ecdfbdfb2b4be9cc.tar.gz external_llvm-f17a25c88b892d30c2b41ba7ecdfbdfb2b4be9cc.tar.bz2 |
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')
-rw-r--r-- | include/llvm/ADT/SmallVector.h | 485 |
1 files changed, 485 insertions, 0 deletions
diff --git a/include/llvm/ADT/SmallVector.h b/include/llvm/ADT/SmallVector.h new file mode 100644 index 0000000..876ca27 --- /dev/null +++ b/include/llvm/ADT/SmallVector.h @@ -0,0 +1,485 @@ +//===- 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 |