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123 lines
4.2 KiB
C++
123 lines
4.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* vim: set ts=8 sts=4 et sw=4 tw=99: */
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// Copyright 2009 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef V8_REGEXP_STACK_H_
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#define V8_REGEXP_STACK_H_
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#include "jspubtd.h"
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#include "js/Utility.h"
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namespace js {
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namespace irregexp {
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class RegExpStack;
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// Maintains a per-thread stack area that can be used by irregexp
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// implementation for its backtracking stack.
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//
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// Since there is only one stack area, the Irregexp implementation is not
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// re-entrant. I.e., no regular expressions may be executed in the same thread
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// during a preempted Irregexp execution.
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class RegExpStackScope
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{
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public:
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// Create and delete an instance to control the life-time of a growing stack.
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// Initializes the stack memory area if necessary.
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explicit RegExpStackScope(JSRuntime* rt);
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// Releases the stack if it has grown.
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~RegExpStackScope();
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private:
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RegExpStack* regexp_stack;
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};
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class RegExpStack
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{
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public:
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// Number of allocated locations on the stack above the limit.
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// No sequence of pushes must be longer that this without doing a stack-limit
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// check.
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static const int kStackLimitSlack = 32;
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RegExpStack();
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~RegExpStack();
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bool init();
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// Resets the buffer if it has grown beyond the default/minimum size.
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void reset();
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// Attempts to grow the stack by at least kStackLimitSlack entries.
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bool grow();
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// Address of allocated memory.
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const void* addressOfBase() { return &base_; }
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const void* addressOfLimit() { return &limit_; }
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void* base() { return base_; }
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void* limit() { return limit_; }
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private:
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// Artificial limit used when no memory has been allocated.
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static const uintptr_t kMemoryTop = static_cast<uintptr_t>(-1);
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// Minimal size of allocated stack area, in bytes.
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static const size_t kMinimumStackSize = 1 * 1024;
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// Maximal size of allocated stack area, in bytes.
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static const size_t kMaximumStackSize = 64 * 1024 * 1024;
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// If size > 0 then base must be non-nullptr.
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void* base_;
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// Length in bytes of base.
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size_t size;
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// If the stack pointer gets above the limit, we should react and
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// either grow the stack or report an out-of-stack exception.
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// There is only a limited number of locations above the stack limit,
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// so users of the stack should check the stack limit during any
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// sequence of pushes longer than this.
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void* limit_;
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void updateLimit() {
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MOZ_ASSERT(size >= kStackLimitSlack * sizeof(void*));
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limit_ = static_cast<uint8_t*>(base()) + size - (kStackLimitSlack * sizeof(void*));
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}
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};
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int
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GrowBacktrackStack(JSRuntime* rt);
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}} // namespace js::irregexp
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#endif // V8_REGEXP_STACK_H_
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