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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
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tree10027f336435511475e392454359edea8e25895d /js/src/irregexp/RegExpStack.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
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+/* -*- 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_