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

src/regexp-macro-assembler.h

Index: src/regexp-macro-assembler.h
diff --git a/src/regexp-macro-assembler.h b/src/regexp-macro-assembler.h
index 878a29715b235f7bc5f1c51b0ef07030f8b2f99f..08c295f6ac29e1ba911197cb4b26e63b59234a6c 100644
--- a/src/regexp-macro-assembler.h
+++ b/src/regexp-macro-assembler.h
@@ -30,7 +30,6 @@
 
 namespace v8 { namespace internal {
 
-
 struct DisjunctDecisionRow {
   RegExpCharacterClass cc;
   Label* on_match;
@@ -42,10 +41,21 @@ class RegExpMacroAssembler {
   enum IrregexpImplementation {
     kIA32Implementation,
     kARMImplementation,
-    kBytecodeImplementation};
+    kBytecodeImplementation
+  };
+
+  enum StackCheckFlag {
+    kNoStackLimitCheck = false,
+    kCheckStackLimit = true
+  };
 
   RegExpMacroAssembler();
   virtual ~RegExpMacroAssembler();
+  // The maximal number of pushes between stack checks. Users must supply
+  // kCheckStackLimit flag to push operations (instead of kNoStackLimitCheck)
+  // at least once for every stack_limit() pushes that are executed. More
+  // often is allowed (and encouraged)

[Erik Corry, 2009/01/12 11:50:13]

Missing full stop, and I see no need to encourage inefficiency.  Also the name
is not descriptive.  Something including the word 'slack' seems more
appropriate.

[Lasse Reichstein, 2009/01/12 13:03:59]

Done.

+  virtual int stack_limit() = 0;
   virtual void AdvanceCurrentPosition(int by) = 0;  // Signed cp change.
   virtual void AdvanceRegister(int reg, int by) = 0;  // r[reg] += by.
   virtual void Backtrack() = 0;
@@ -145,9 +155,11 @@ class RegExpMacroAssembler {
                                     int characters = 1) = 0;
   virtual void PopCurrentPosition() = 0;
   virtual void PopRegister(int register_index) = 0;
-  virtual void PushBacktrack(Label* label) = 0;
-  virtual void PushCurrentPosition() = 0;
-  virtual void PushRegister(int register_index) = 0;
+  virtual void PushBacktrack(Label* label,
+                             StackCheckFlag check_stack_limit) = 0;
+  virtual void PushCurrentPosition(StackCheckFlag check_stack_limit) = 0;
+  virtual void PushRegister(int register_index,
+                            StackCheckFlag check_stack_limit) = 0;
   virtual void ReadCurrentPositionFromRegister(int reg) = 0;
   virtual void ReadStackPointerFromRegister(int reg) = 0;
   virtual void SetRegister(int register_index, int to) = 0;