X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=folly%2Fsmall_vector.h;h=12eba17f76ea3effee4c62e576460824b0ea1228;hb=58a70372d16f13a952ecc046fa90ce055fb6f36a;hp=318fcbfdf7ece46dc425c9ef5abbe484a1d87493;hpb=bd51c8dbebd7ee9de3db64b8d84a814a00639e0a;p=folly.git diff --git a/folly/small_vector.h b/folly/small_vector.h index 318fcbfd..12eba17f 100644 --- a/folly/small_vector.h +++ b/folly/small_vector.h @@ -1,5 +1,5 @@ /* - * Copyright 2015 Facebook, Inc. + * Copyright 2017 Facebook, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -20,10 +20,8 @@ * * @author Jordan DeLong */ -#ifndef FOLLY_SMALL_VECTOR_H_ -#define FOLLY_SMALL_VECTOR_H_ -#include +#pragma once #include #include @@ -44,30 +42,17 @@ #include #include #include -#include +#include +#include #include - -#if defined(__GNUC__) && FOLLY_X64 -# include -# define FB_PACK_ATTR FOLLY_PACK_ATTR -# define FB_PACK_PUSH FOLLY_PACK_PUSH -# define FB_PACK_POP FOLLY_PACK_POP -#else -# define FB_PACK_ATTR -# define FB_PACK_PUSH -# define FB_PACK_POP -#endif - -#if FOLLY_HAVE_MALLOC_SIZE - extern "C" std::size_t malloc_size(const void*); -# if !FOLLY_HAVE_MALLOC_USABLE_SIZE -# define malloc_usable_size malloc_size -# endif -# ifndef malloc_usable_size -# define malloc_usable_size malloc_size -# endif -#endif +#include +#include +#include +#include +#include +#include +#include // Ignore shadowing warnings within this file, so includers can use -Wshadow. #pragma GCC diagnostic push @@ -136,6 +121,42 @@ namespace detail { std::memmove(out, first, (last - first) * sizeof *first); } + /* + * Move a range to a range of uninitialized memory. Assumes the + * ranges don't overlap. Inserts an element at out + pos using emplaceFunc(). + * out will contain (end - begin) + 1 elements on success and none on failure. + * If emplaceFunc() throws [begin, end) is unmodified. + */ + template + void moveToUninitializedEmplace( + T* begin, + T* end, + T* out, + Size pos, + EmplaceFunc&& emplaceFunc) { + // Must be called first so that if it throws [begin, end) is unmodified. + // We have to support the strong exception guarantee for emplace_back(). + emplaceFunc(out + pos); + // move old elements to the left of the new one + try { + detail::moveToUninitialized(begin, begin + pos, out); + } catch (...) { + out[pos].~T(); + throw; + } + // move old elements to the right of the new one + try { + if (begin + pos < end) { + detail::moveToUninitialized(begin + pos, end, out + pos + 1); + } + } catch (...) { + for (Size i = 0; i <= pos; ++i) { + out[i].~T(); + } + throw; + } + } + /* * Move objects in memory to the right into some uninitialized * memory, where the region overlaps. This doesn't just use @@ -342,7 +363,7 @@ namespace detail { } ////////////////////////////////////////////////////////////////////// -FB_PACK_PUSH +FOLLY_PACK_PUSH template, - boost::mpl::int_ - >::type::value - }; + static constexpr std::size_t MaxInline{ + constexpr_max(sizeof(Value*) / sizeof(Value), RequestedMaxInline)}; -public: + public: typedef std::size_t size_type; typedef Value value_type; typedef value_type& reference; @@ -414,8 +431,12 @@ public: constructImpl(il.begin(), il.end(), std::false_type()); } - explicit small_vector(size_type n, value_type const& t = value_type()) { - doConstruct(n, t); + explicit small_vector(size_type n) { + doConstruct(n, [&](void* p) { new (p) value_type(); }); + } + + small_vector(size_type n, value_type const& t) { + doConstruct(n, [&](void* p) { new (p) value_type(t); }); } template @@ -458,7 +479,7 @@ public: } static constexpr size_type max_size() { - return !BaseType::kShouldUseHeap ? MaxInline + return !BaseType::kShouldUseHeap ? static_cast(MaxInline) : BaseType::policyMaxSize(); } @@ -503,7 +524,9 @@ public: auto thisCapacity = this->capacity(); auto oCapacity = o.capacity(); - std::swap(unpackHack(&u.pdata_.heap_), unpackHack(&o.u.pdata_.heap_)); + auto* tmp = u.pdata_.heap_; + u.pdata_.heap_ = o.u.pdata_.heap_; + o.u.pdata_.heap_ = tmp; this->setCapacity(oCapacity); o.setCapacity(thisCapacity); @@ -636,7 +659,7 @@ public: size_type capacity() const { if (this->isExtern()) { if (u.hasCapacity()) { - return *u.getCapacity(); + return u.getCapacity(); } return malloc_usable_size(u.pdata_.heap_) / sizeof(value_type); } @@ -652,44 +675,28 @@ public: tmp.swap(*this); } - template + template void emplace_back(Args&&... args) { - // call helper function for static dispatch of special cases - emplaceBack(std::forward(args)...); - } - - void emplace_back(const value_type& t) { - push_back(t); - } - void emplace_back(value_type& t) { - push_back(t); - } - - void emplace_back(value_type&& t) { - push_back(std::move(t)); - } - - void push_back(value_type&& t) { if (capacity() == size()) { - makeSize(std::max(size_type(2), 3 * size() / 2), &t, size()); + // Any of args may be references into the vector. + // When we are reallocating, we have to be careful to construct the new + // element before modifying the data in the old buffer. + makeSize( + size() + 1, + [&](void* p) { new (p) value_type(std::forward(args)...); }, + size()); } else { - new (end()) value_type(std::move(t)); + new (end()) value_type(std::forward(args)...); } this->setSize(size() + 1); } + void push_back(value_type&& t) { + return emplace_back(std::move(t)); + } + void push_back(value_type const& t) { - // TODO: we'd like to make use of makeSize (it can be optimized better, - // because it manipulates the internals) - // unfortunately the current implementation only supports moving from - // a supplied rvalue, and doing an extra move just to reuse it is a perf - // net loss - if (size() == capacity()) {// && isInside(&t)) { - value_type tmp(t); - emplaceBack(std::move(tmp)); - } else { - emplaceBack(t); - } + emplace_back(t); } void pop_back() { @@ -707,10 +714,12 @@ public: auto offset = p - begin(); if (capacity() == size()) { - makeSize(size() + 1, &t, offset); + makeSize( + size() + 1, + [&t](void* ptr) { new (ptr) value_type(std::move(t)); }, + offset); this->setSize(this->size() + 1); } else { - makeSize(size() + 1); detail::moveObjectsRight(data() + offset, data() + size(), data() + size() + 1); @@ -803,44 +812,24 @@ public: reference at(size_type i) { if (i >= size()) { - throw std::out_of_range("index out of range"); + std::__throw_out_of_range("index out of range"); } return (*this)[i]; } const_reference at(size_type i) const { if (i >= size()) { - throw std::out_of_range("index out of range"); + std::__throw_out_of_range("index out of range"); } return (*this)[i]; } private: - /* - * This is doing the same like emplace_back, but we need this helper - * to catch the special case - see the next overload function.. - */ - template - void emplaceBack(Args&&... args) { - makeSize(size() + 1); - new (end()) value_type(std::forward(args)...); - this->setSize(size() + 1); - } - static iterator unconst(const_iterator it) { return const_cast(it); } - /* - * g++ doesn't allow you to bind a non-const reference to a member - * of a packed structure, presumably because it would make it too - * easy to accidentally make an unaligned memory access? - */ - template static T& unpackHack(T* p) { - return *p; - } - // The std::false_type argument is part of disambiguating the // iterator insert functions from integral types (see insert().) template @@ -883,7 +872,7 @@ private: // With iterators that only allow a single pass, we can't really // do anything sane here. while (first != last) { - push_back(*first++); + emplace_back(*first++); } return; } @@ -903,13 +892,12 @@ private: } } - void doConstruct(size_type n, value_type const& val) { + template + void doConstruct(size_type n, InitFunc&& func) { makeSize(n); this->setSize(n); try { - detail::populateMemForward(data(), n, - [&] (void* p) { new (p) value_type(val); } - ); + detail::populateMemForward(data(), n, std::forward(func)); } catch (...) { if (this->isExtern()) { u.freeHeap(); @@ -921,33 +909,53 @@ private: // The true_type means we should forward to the size_t,value_type // overload. void constructImpl(size_type n, value_type const& val, std::true_type) { - doConstruct(n, val); + doConstruct(n, [&](void* p) { new (p) value_type(val); }); + } + + /* + * Compute the size after growth. + */ + size_type computeNewSize() const { + return std::min((3 * capacity()) / 2 + 1, max_size()); + } + + void makeSize(size_type newSize) { + makeSizeInternal(newSize, false, [](void*) { assume_unreachable(); }, 0); } - void makeSize(size_type size, value_type* v = nullptr) { - makeSize(size, v, size - 1); + template + void makeSize(size_type newSize, EmplaceFunc&& emplaceFunc, size_type pos) { + assert(size() == capacity()); + makeSizeInternal( + newSize, true, std::forward(emplaceFunc), pos); } /* - * Ensure we have a large enough memory region to be size `size'. + * Ensure we have a large enough memory region to be size `newSize'. * Will move/copy elements if we are spilling to heap_ or needed to * allocate a new region, but if resized in place doesn't initialize * anything in the new region. In any case doesn't change size(). * Supports insertion of new element during reallocation by given * pointer to new element and position of new element. - * NOTE: If reallocation is not needed, and new element should be - * inserted in the middle of vector (not at the end), do the move - * objects and insertion outside the function, otherwise exception is thrown. + * NOTE: If reallocation is not needed, insert must be false, + * because we only know how to emplace elements into new memory. */ - void makeSize(size_type size, value_type* v, size_type pos) { - if (size > this->max_size()) { + template + void makeSizeInternal( + size_type newSize, + bool insert, + EmplaceFunc&& emplaceFunc, + size_type pos) { + if (newSize > max_size()) { throw std::length_error("max_size exceeded in small_vector"); } - if (size <= this->capacity()) { + if (newSize <= capacity()) { + assert(!insert); return; } + newSize = std::max(newSize, computeNewSize()); - auto needBytes = size * sizeof(value_type); + auto needBytes = newSize * sizeof(value_type); // If the capacity isn't explicitly stored inline, but the heap // allocation is grown to over some threshold, we should store // a capacity at the front of the heap allocation. @@ -967,44 +975,18 @@ private: detail::shiftPointer(newh, kHeapifyCapacitySize) : newh); - if (v != nullptr) { - // move new element - try { - new (&newp[pos]) value_type(std::move(*v)); - } catch (...) { - free(newh); - throw; - } - - // move old elements to the left of the new one - try { - detail::moveToUninitialized(begin(), begin() + pos, newp); - } catch (...) { - newp[pos].~value_type(); - free(newh); - throw; - } - - // move old elements to the right of the new one - try { - if (pos < size-1) { - detail::moveToUninitialized(begin() + pos, end(), newp + pos + 1); - } - } catch (...) { - for (size_type i = 0; i <= pos; ++i) { - newp[i].~value_type(); - } - free(newh); - throw; - } - } else { - // move without inserting new element - try { + try { + if (insert) { + // move and insert the new element + detail::moveToUninitializedEmplace( + begin(), end(), newp, pos, std::forward(emplaceFunc)); + } else { + // move without inserting new element detail::moveToUninitialized(begin(), end(), newp); - } catch (...) { - free(newh); - throw; } + } catch (...) { + free(newh); + throw; } for (auto& val : *this) { val.~value_type(); @@ -1032,7 +1014,7 @@ private: assert(this->isExtern()); if (u.hasCapacity()) { assert(newCapacity < std::numeric_limits::max()); - *u.getCapacity() = InternalSizeType(newCapacity); + u.setCapacity(newCapacity); } } @@ -1041,32 +1023,43 @@ private: void* heap_; InternalSizeType capacity_; - InternalSizeType* getCapacity() { - return &capacity_; + InternalSizeType getCapacity() const { + return capacity_; + } + void setCapacity(InternalSizeType c) { + capacity_ = c; } - } FB_PACK_ATTR; + } FOLLY_PACK_ATTR; struct HeapPtr { // Lower order bit of heap_ is used as flag to indicate whether capacity is // stored at the front of the heap allocation. void* heap_; - InternalSizeType* getCapacity() { + InternalSizeType getCapacity() const { assert(detail::pointerFlagGet(heap_)); - return static_cast( - detail::pointerFlagClear(heap_)); + return *static_cast(detail::pointerFlagClear(heap_)); + } + void setCapacity(InternalSizeType c) { + *static_cast(detail::pointerFlagClear(heap_)) = c; } - } FB_PACK_ATTR; + } FOLLY_PACK_ATTR; -#if FOLLY_X64 - typedef unsigned char InlineStorageType[sizeof(value_type) * MaxInline]; +#if (FOLLY_X64 || FOLLY_PPC64) + typedef unsigned char InlineStorageDataType[sizeof(value_type) * MaxInline]; #else typedef typename std::aligned_storage< sizeof(value_type) * MaxInline, alignof(value_type) - >::type InlineStorageType; + >::type InlineStorageDataType; #endif + typedef typename std::conditional< + sizeof(value_type) * MaxInline != 0, + InlineStorageDataType, + void* + >::type InlineStorageType; + static bool const kHasInlineCapacity = sizeof(HeapPtrWithCapacity) < sizeof(InlineStorageType); @@ -1114,20 +1107,20 @@ private: bool hasCapacity() const { return kHasInlineCapacity || detail::pointerFlagGet(pdata_.heap_); } - InternalSizeType* getCapacity() { + InternalSizeType getCapacity() const { return pdata_.getCapacity(); } - InternalSizeType* getCapacity() const { - return const_cast(this)->getCapacity(); + void setCapacity(InternalSizeType c) { + pdata_.setCapacity(c); } void freeHeap() { auto vp = detail::pointerFlagClear(pdata_.heap_); free(vp); } - } FB_PACK_ATTR u; -} FB_PACK_ATTR; -FB_PACK_POP + } FOLLY_PACK_ATTR u; +} FOLLY_PACK_ATTR; +FOLLY_PACK_POP ////////////////////////////////////////////////////////////////////// @@ -1141,14 +1134,16 @@ void swap(small_vector& a, ////////////////////////////////////////////////////////////////////// -} +namespace detail { -#pragma GCC diagnostic pop +// Format support. +template +struct IndexableTraits> + : public IndexableTraitsSeq> { +}; -#ifdef FB_PACK_ATTR -# undef FB_PACK_ATTR -# undef FB_PACK_PUSH -# undef FB_PACK_POP -#endif +} // namespace detail -#endif +} // namespace folly + +#pragma GCC diagnostic pop