| /* -*- 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. |
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| // 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 |
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| |
| #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*)); |
| } |
| }; |
| |
| int |
| GrowBacktrackStack(JSRuntime* rt); |
| |
| }} // namespace js::irregexp |
| |
| #endif // V8_REGEXP_STACK_H_ |