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

src/regexp-macro-assembler-tracer.h

Index: src/regexp-macro-assembler-tracer.h
diff --git a/src/regexp-macro-assembler-tracer.h b/src/regexp-macro-assembler-tracer.h
index f5b8851cf65f490b40c1b32b94e5232f946d036b..28f6bc26ff02f0d8ca5846f1e588285147a9ef35 100644
--- a/src/regexp-macro-assembler-tracer.h
+++ b/src/regexp-macro-assembler-tracer.h
@@ -35,6 +35,7 @@ class RegExpMacroAssemblerTracer: public RegExpMacroAssembler {
  public:
   explicit RegExpMacroAssemblerTracer(RegExpMacroAssembler* assembler);
   virtual ~RegExpMacroAssemblerTracer();
+  virtual int stack_limit() { return assembler_->stack_limit(); }
 
   virtual void AdvanceCurrentPosition(int by);  // Signed cp change.
   virtual void AdvanceRegister(int reg, int by);  // r[reg] += by.
@@ -96,9 +97,10 @@ class RegExpMacroAssemblerTracer: public RegExpMacroAssembler {
                                     int characters = 1);
   virtual void PopCurrentPosition();
   virtual void PopRegister(int register_index);
-  virtual void PushBacktrack(Label* label);
-  virtual void PushCurrentPosition();
-  virtual void PushRegister(int register_index);
+  virtual void PushBacktrack(Label* label, StackCheckFlag check_stack_limit);
+  virtual void PushCurrentPosition(StackCheckFlag check_stack_limit);
+  virtual void PushRegister(int register_index,
+                            StackCheckFlag check_stack_limit);
   virtual void ReadCurrentPositionFromRegister(int reg);
   virtual void ReadStackPointerFromRegister(int reg);
   virtual void SetRegister(int register_index, int to);