* Move irregexp backtrack stack to external memory area, instead of the system stack.

src/regexp-stack.cc

Index: src/regexp-stack.cc
diff --git a/src/regexp-stack.cc b/src/regexp-stack.cc
new file mode 100644
index 0000000000000000000000000000000000000000..05daa58d4eb3cf269bcf3fb39a12a9f14dc968dd
--- /dev/null
+++ b/src/regexp-stack.cc
@@ -0,0 +1,94 @@
+// 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.
+
+#include "v8.h"
+#include "top.h"
+#include "regexp-stack.h"
+
+namespace v8 { namespace internal {
+
+RegExpStack::RegExpStack() {
+  // Initialize, if not already initialized.
+  RegExpStack::EnsureCapacity(0);
+}
+
+
+RegExpStack::~RegExpStack() {
+  // Reset the buffer if it has grown.
+  RegExpStack::Reset();
+}
+
+
+char* RegExpStack::ArchiveStack(char* to) {
+  size_t size = sizeof(thread_local_);
+  memcpy(reinterpret_cast<void*>(to),
+         &thread_local_,
+         size);
+  thread_local_ = ThreadLocal();
+  return to + size;
+}
+
+
+char* RegExpStack::RestoreStack(char* from) {
+  size_t size = sizeof(thread_local_);
+  memcpy(&thread_local_, reinterpret_cast<void*>(from), size);
+  return from + size;
+}
+
+
+void RegExpStack::Reset() {
+  if (thread_local_.memory_size_ > kMinimumStackSize) {
+    DeleteArray(thread_local_.memory_);
+    thread_local_ = ThreadLocal();
+  }
+}
+
+
+Address RegExpStack::EnsureCapacity(size_t size) {
+  if (size > kMaximumStackSize) return NULL;
+  if (size < kMinimumStackSize) size = kMinimumStackSize;
+  if (thread_local_.memory_size_ < size) {
+    Address new_memory = NewArray<byte>(size);
+    if (thread_local_.memory_size_ > 0) {
+      // Copy original memory into top of new memory.
+      memcpy(reinterpret_cast<void*>(
+          new_memory + size - thread_local_.memory_size_),
+             reinterpret_cast<void*>(thread_local_.memory_),
+             thread_local_.memory_size_);
+      DeleteArray(thread_local_.memory_);
+    }
+    thread_local_.memory_ = new_memory;
+    thread_local_.memory_size_ = size;
+    thread_local_.limit_ = new_memory + kStackLimitSlack * kPointerSize;
+  }
+  return thread_local_.memory_ + thread_local_.memory_size_;
+}
+
+
+RegExpStack::ThreadLocal RegExpStack::thread_local_;
+
+}}  // namespace v8::internal