1 // 2 // Copyright (C) 2002-2005 3Dlabs Inc. Ltd. 3 // Copyright (C) 2012-2013 LunarG, Inc. 4 // 5 // All rights reserved. 6 // 7 // Redistribution and use in source and binary forms, with or without 8 // modification, are permitted provided that the following conditions 9 // are met: 10 // 11 // Redistributions of source code must retain the above copyright 12 // notice, this list of conditions and the following disclaimer. 13 // 14 // Redistributions in binary form must reproduce the above 15 // copyright notice, this list of conditions and the following 16 // disclaimer in the documentation and/or other materials provided 17 // with the distribution. 18 // 19 // Neither the name of 3Dlabs Inc. Ltd. nor the names of its 20 // contributors may be used to endorse or promote products derived 21 // from this software without specific prior written permission. 22 // 23 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 26 // FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 27 // COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 28 // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 29 // BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 30 // LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 31 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 // LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 33 // ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 34 // POSSIBILITY OF SUCH DAMAGE. 35 // 36 37 #ifndef _POOLALLOC_INCLUDED_ 38 #define _POOLALLOC_INCLUDED_ 39 40 #ifdef _DEBUG 41 # define GUARD_BLOCKS // define to enable guard block sanity checking 42 #endif 43 44 // 45 // This header defines an allocator that can be used to efficiently 46 // allocate a large number of small requests for heap memory, with the 47 // intention that they are not individually deallocated, but rather 48 // collectively deallocated at one time. 49 // 50 // This simultaneously 51 // 52 // * Makes each individual allocation much more efficient; the 53 // typical allocation is trivial. 54 // * Completely avoids the cost of doing individual deallocation. 55 // * Saves the trouble of tracking down and plugging a large class of leaks. 56 // 57 // Individual classes can use this allocator by supplying their own 58 // new and delete methods. 59 // 60 // STL containers can use this allocator by using the pool_allocator 61 // class as the allocator (second) template argument. 62 // 63 64 #include <cstddef> 65 #include <cstring> 66 #include <vector> 67 68 namespace glslang { 69 70 // If we are using guard blocks, we must track each individual 71 // allocation. If we aren't using guard blocks, these 72 // never get instantiated, so won't have any impact. 73 // 74 75 class TAllocation { 76 public: 77 TAllocation(size_t size, unsigned char* mem, TAllocation* prev = 0) : size(size)78 size(size), mem(mem), prevAlloc(prev) { 79 // Allocations are bracketed: 80 // [allocationHeader][initialGuardBlock][userData][finalGuardBlock] 81 // This would be cleaner with if (guardBlockSize)..., but that 82 // makes the compiler print warnings about 0 length memsets, 83 // even with the if() protecting them. 84 # ifdef GUARD_BLOCKS 85 memset(preGuard(), guardBlockBeginVal, guardBlockSize); 86 memset(data(), userDataFill, size); 87 memset(postGuard(), guardBlockEndVal, guardBlockSize); 88 # endif 89 } 90 check()91 void check() const { 92 checkGuardBlock(preGuard(), guardBlockBeginVal, "before"); 93 checkGuardBlock(postGuard(), guardBlockEndVal, "after"); 94 } 95 96 void checkAllocList() const; 97 98 // Return total size needed to accommodate user buffer of 'size', 99 // plus our tracking data. allocationSize(size_t size)100 inline static size_t allocationSize(size_t size) { 101 return size + 2 * guardBlockSize + headerSize(); 102 } 103 104 // Offset from surrounding buffer to get to user data buffer. offsetAllocation(unsigned char * m)105 inline static unsigned char* offsetAllocation(unsigned char* m) { 106 return m + guardBlockSize + headerSize(); 107 } 108 109 private: 110 void checkGuardBlock(unsigned char* blockMem, unsigned char val, const char* locText) const; 111 112 // Find offsets to pre and post guard blocks, and user data buffer preGuard()113 unsigned char* preGuard() const { return mem + headerSize(); } data()114 unsigned char* data() const { return preGuard() + guardBlockSize; } postGuard()115 unsigned char* postGuard() const { return data() + size; } 116 117 size_t size; // size of the user data area 118 unsigned char* mem; // beginning of our allocation (pts to header) 119 TAllocation* prevAlloc; // prior allocation in the chain 120 121 const static unsigned char guardBlockBeginVal; 122 const static unsigned char guardBlockEndVal; 123 const static unsigned char userDataFill; 124 125 const static size_t guardBlockSize; 126 # ifdef GUARD_BLOCKS headerSize()127 inline static size_t headerSize() { return sizeof(TAllocation); } 128 # else headerSize()129 inline static size_t headerSize() { return 0; } 130 # endif 131 }; 132 133 // 134 // There are several stacks. One is to track the pushing and popping 135 // of the user, and not yet implemented. The others are simply a 136 // repositories of free pages or used pages. 137 // 138 // Page stacks are linked together with a simple header at the beginning 139 // of each allocation obtained from the underlying OS. Multi-page allocations 140 // are returned to the OS. Individual page allocations are kept for future 141 // re-use. 142 // 143 // The "page size" used is not, nor must it match, the underlying OS 144 // page size. But, having it be about that size or equal to a set of 145 // pages is likely most optimal. 146 // 147 class TPoolAllocator { 148 public: 149 TPoolAllocator(int growthIncrement = 8*1024, int allocationAlignment = 16); 150 151 // 152 // Don't call the destructor just to free up the memory, call pop() 153 // 154 ~TPoolAllocator(); 155 156 // 157 // Call push() to establish a new place to pop memory too. Does not 158 // have to be called to get things started. 159 // 160 void push(); 161 162 // 163 // Call pop() to free all memory allocated since the last call to push(), 164 // or if no last call to push, frees all memory since first allocation. 165 // 166 void pop(); 167 168 // 169 // Call popAll() to free all memory allocated. 170 // 171 void popAll(); 172 173 // 174 // Call allocate() to actually acquire memory. Returns 0 if no memory 175 // available, otherwise a properly aligned pointer to 'numBytes' of memory. 176 // 177 void* allocate(size_t numBytes); 178 179 // 180 // There is no deallocate. The point of this class is that 181 // deallocation can be skipped by the user of it, as the model 182 // of use is to simultaneously deallocate everything at once 183 // by calling pop(), and to not have to solve memory leak problems. 184 // 185 186 protected: 187 friend struct tHeader; 188 189 struct tHeader { tHeadertHeader190 tHeader(tHeader* nextPage, size_t pageCount) : 191 #ifdef GUARD_BLOCKS 192 lastAllocation(0), 193 #endif 194 nextPage(nextPage), pageCount(pageCount) { } 195 ~tHeadertHeader196 ~tHeader() { 197 #ifdef GUARD_BLOCKS 198 if (lastAllocation) 199 lastAllocation->checkAllocList(); 200 #endif 201 } 202 203 #ifdef GUARD_BLOCKS 204 TAllocation* lastAllocation; 205 #endif 206 tHeader* nextPage; 207 size_t pageCount; 208 }; 209 210 struct tAllocState { 211 size_t offset; 212 tHeader* page; 213 }; 214 typedef std::vector<tAllocState> tAllocStack; 215 216 // Track allocations if and only if we're using guard blocks 217 #ifndef GUARD_BLOCKS initializeAllocation(tHeader *,unsigned char * memory,size_t)218 void* initializeAllocation(tHeader*, unsigned char* memory, size_t) { 219 #else 220 void* initializeAllocation(tHeader* block, unsigned char* memory, size_t numBytes) { 221 new(memory) TAllocation(numBytes, memory, block->lastAllocation); 222 block->lastAllocation = reinterpret_cast<TAllocation*>(memory); 223 #endif 224 225 // This is optimized entirely away if GUARD_BLOCKS is not defined. 226 return TAllocation::offsetAllocation(memory); 227 } 228 229 size_t pageSize; // granularity of allocation from the OS 230 size_t alignment; // all returned allocations will be aligned at 231 // this granularity, which will be a power of 2 232 size_t alignmentMask; 233 size_t headerSkip; // amount of memory to skip to make room for the 234 // header (basically, size of header, rounded 235 // up to make it aligned 236 size_t currentPageOffset; // next offset in top of inUseList to allocate from 237 tHeader* freeList; // list of popped memory 238 tHeader* inUseList; // list of all memory currently being used 239 tAllocStack stack; // stack of where to allocate from, to partition pool 240 241 int numCalls; // just an interesting statistic 242 size_t totalBytes; // just an interesting statistic 243 private: 244 TPoolAllocator& operator=(const TPoolAllocator&); // don't allow assignment operator 245 TPoolAllocator(const TPoolAllocator&); // don't allow default copy constructor 246 }; 247 248 // 249 // There could potentially be many pools with pops happening at 250 // different times. But a simple use is to have a global pop 251 // with everyone using the same global allocator. 252 // 253 extern TPoolAllocator& GetThreadPoolAllocator(); 254 void SetThreadPoolAllocator(TPoolAllocator* poolAllocator); 255 256 // 257 // This STL compatible allocator is intended to be used as the allocator 258 // parameter to templatized STL containers, like vector and map. 259 // 260 // It will use the pools for allocation, and not 261 // do any deallocation, but will still do destruction. 262 // 263 template<class T> 264 class pool_allocator { 265 public: 266 typedef size_t size_type; 267 typedef ptrdiff_t difference_type; 268 typedef T *pointer; 269 typedef const T *const_pointer; 270 typedef T& reference; 271 typedef const T& const_reference; 272 typedef T value_type; 273 template<class Other> 274 struct rebind { 275 typedef pool_allocator<Other> other; 276 }; address(reference x)277 pointer address(reference x) const { return &x; } address(const_reference x)278 const_pointer address(const_reference x) const { return &x; } 279 pool_allocator()280 pool_allocator() : allocator(GetThreadPoolAllocator()) { } pool_allocator(TPoolAllocator & a)281 pool_allocator(TPoolAllocator& a) : allocator(a) { } pool_allocator(const pool_allocator<T> & p)282 pool_allocator(const pool_allocator<T>& p) : allocator(p.allocator) { } 283 284 template<class Other> pool_allocator(const pool_allocator<Other> & p)285 pool_allocator(const pool_allocator<Other>& p) : allocator(p.getAllocator()) { } 286 allocate(size_type n)287 pointer allocate(size_type n) { 288 return reinterpret_cast<pointer>(getAllocator().allocate(n * sizeof(T))); } allocate(size_type n,const void *)289 pointer allocate(size_type n, const void*) { 290 return reinterpret_cast<pointer>(getAllocator().allocate(n * sizeof(T))); } 291 deallocate(void *,size_type)292 void deallocate(void*, size_type) { } deallocate(pointer,size_type)293 void deallocate(pointer, size_type) { } 294 _Charalloc(size_t n)295 pointer _Charalloc(size_t n) { 296 return reinterpret_cast<pointer>(getAllocator().allocate(n)); } 297 construct(pointer p,const T & val)298 void construct(pointer p, const T& val) { new ((void *)p) T(val); } destroy(pointer p)299 void destroy(pointer p) { p->T::~T(); } 300 301 bool operator==(const pool_allocator& rhs) const { return &getAllocator() == &rhs.getAllocator(); } 302 bool operator!=(const pool_allocator& rhs) const { return &getAllocator() != &rhs.getAllocator(); } 303 max_size()304 size_type max_size() const { return static_cast<size_type>(-1) / sizeof(T); } max_size(int size)305 size_type max_size(int size) const { return static_cast<size_type>(-1) / size; } 306 getAllocator()307 TPoolAllocator& getAllocator() const { return allocator; } 308 309 protected: 310 pool_allocator& operator=(const pool_allocator&) { return *this; } 311 TPoolAllocator& allocator; 312 }; 313 314 } // end namespace glslang 315 316 #endif // _POOLALLOC_INCLUDED_ 317