/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- * vim: set ts=8 sts=4 et sw=4 tw=99: */ // 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_ #include "jspubtd.h" #include "js/Utility.h" namespace js { namespace irregexp { class RegExpStack; // Maintains a per-thread 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 RegExpStackScope { public: // Create and delete an instance to control the life-time of a growing stack. // Initializes the stack memory area if necessary. explicit RegExpStackScope(JSRuntime* rt); // Releases the stack if it has grown. ~RegExpStackScope(); private: RegExpStack* regexp_stack; }; class RegExpStack { public: // Number of allocated locations on the stack above the limit. // No sequence of pushes must be longer that this without doing a stack-limit // check. static const int kStackLimitSlack = 32; RegExpStack(); ~RegExpStack(); bool init(); // Resets the buffer if it has grown beyond the default/minimum size. void reset(); // Attempts to grow the stack by at least kStackLimitSlack entries. bool grow(); // Address of allocated memory. const void* addressOfBase() { return &base_; } const void* addressOfLimit() { return &limit_; } void* base() { return base_; } void* limit() { return limit_; } 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, in bytes. static const size_t kMinimumStackSize = 1 * 1024; // Maximal size of allocated stack area, in bytes. static const size_t kMaximumStackSize = 64 * 1024 * 1024; // If size > 0 then base must be non-nullptr. void* base_; // Length in bytes of base. size_t size; // If the stack pointer gets above 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 above the stack limit, // so users of the stack should check the stack limit during any // sequence of pushes longer than this. void* limit_; void updateLimit() { MOZ_ASSERT(size >= kStackLimitSlack * sizeof(void*)); limit_ = static_cast<uint8_t*>(base()) + size - (kStackLimitSlack * sizeof(void*)); } }; bool GrowBacktrackStack(JSRuntime* rt); }} // namespace js::irregexp #endif // V8_REGEXP_STACK_H_