| // Copyright 2009 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef V8_REGEXP_STACK_H_ |
| #define V8_REGEXP_STACK_H_ |
| |
| namespace v8 { |
| namespace internal { |
| |
| // Maintains a per-v8thread stack area that can be used by irregexp |
| // implementation for its backtracking stack. |
| // Since there is only one stack area, the Irregexp implementation is not |
| // re-entrant. I.e., no regular expressions may be executed in the same thread |
| // during a preempted Irregexp execution. |
| class RegExpStack { |
| public: |
| // Number of allocated locations on the stack below the limit. |
| // No sequence of pushes must be longer that this without doing a stack-limit |
| // check. |
| static const int kStackLimitSlack = 32; |
| |
| // Create and delete an instance to control the life-time of a growing stack. |
| RegExpStack(); // Initializes the stack memory area if necessary. |
| ~RegExpStack(); // Releases the stack if it has grown. |
| |
| // Gives the top of the memory used as stack. |
| static Address stack_base() { |
| ASSERT(thread_local_.memory_size_ != 0); |
| return thread_local_.memory_ + thread_local_.memory_size_; |
| } |
| |
| // The total size of the memory allocated for the stack. |
| static size_t stack_capacity() { return thread_local_.memory_size_; } |
| |
| // If the stack pointer gets below the limit, we should react and |
| // either grow the stack or report an out-of-stack exception. |
| // There is only a limited number of locations below the stack limit, |
| // so users of the stack should check the stack limit during any |
| // sequence of pushes longer that this. |
| static Address* limit_address() { return &(thread_local_.limit_); } |
| |
| // Ensures that there is a memory area with at least the specified size. |
| // If passing zero, the default/minimum size buffer is allocated. |
| static Address EnsureCapacity(size_t size); |
| |
| // Thread local archiving. |
| static size_t ArchiveSpacePerThread() { return sizeof(thread_local_); } |
| static char* ArchiveStack(char* to); |
| static char* RestoreStack(char* from); |
| |
| private: |
| // Artificial limit used when no memory has been allocated. |
| static const uintptr_t kMemoryTop = static_cast<uintptr_t>(-1); |
| |
| // Minimal size of allocated stack area. |
| static const size_t kMinimumStackSize = 1 * KB; |
| |
| // Maximal size of allocated stack area. |
| static const size_t kMaximumStackSize = 64 * MB; |
| |
| // Structure holding the allocated memory, size and limit. |
| struct ThreadLocal { |
| ThreadLocal() |
| : memory_(NULL), |
| memory_size_(0), |
| limit_(reinterpret_cast<Address>(kMemoryTop)) {} |
| // If memory_size_ > 0 then memory_ must be non-NULL. |
| Address memory_; |
| size_t memory_size_; |
| Address limit_; |
| }; |
| |
| // Resets the buffer if it has grown beyond the default/minimum size. |
| // After this, the buffer is either the default size, or it is empty, so |
| // you have to call EnsureCapacity before using it again. |
| static void Reset(); |
| |
| static ThreadLocal thread_local_; |
| }; |
| |
| }} // namespace v8::internal |
| |
| #endif // V8_REGEXP_STACK_H_ |