Experimental: merge from bleeding_edge. Merge up to and including...

src/regexp-macro-assembler.h

Index: src/regexp-macro-assembler.h
===================================================================
--- src/regexp-macro-assembler.h	(revision 1085)
+++ src/regexp-macro-assembler.h	(working copy)
@@ -30,7 +30,6 @@
 
 namespace v8 { namespace internal {
 
-
 struct DisjunctDecisionRow {
   RegExpCharacterClass cc;
   Label* on_match;
@@ -42,12 +41,24 @@
   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.
+  virtual int stack_limit_slack() = 0;
   virtual void AdvanceCurrentPosition(int by) = 0;  // Signed cp change.
   virtual void AdvanceRegister(int reg, int by) = 0;  // r[reg] += by.
+  // Continues execution from the position pushed on the top of the backtrack
+  // stack by an earlier PushBacktrack(Label*).
   virtual void Backtrack() = 0;
   virtual void Bind(Label* label) = 0;
   // Check the current character against a bitmap.  The range of the current
@@ -135,6 +146,9 @@
   // Check whether a register is < a given constant and go to a label if it is.
   // Backtracks instead if the label is NULL.
   virtual void IfRegisterLT(int reg, int comparand, Label* if_lt) = 0;
+  // Check whether a register is == to the current position and go to a
+  // label if it is.
+  virtual void IfRegisterEqPos(int reg, Label* if_eq) = 0;
   virtual IrregexpImplementation Implementation() = 0;
   virtual void LoadCurrentCharacter(int cp_offset,
                                     Label* on_end_of_input,
@@ -142,14 +156,18 @@
                                     int characters = 1) = 0;
   virtual void PopCurrentPosition() = 0;
   virtual void PopRegister(int register_index) = 0;
+  // Pushes the label on the backtrack stack, so that a following Backtrack
+  // will go to this label. Always checks the backtrack stack limit.
   virtual void PushBacktrack(Label* label) = 0;
   virtual void PushCurrentPosition() = 0;
-  virtual void PushRegister(int register_index) = 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;
   virtual void Succeed() = 0;
   virtual void WriteCurrentPositionToRegister(int reg, int cp_offset) = 0;
+  virtual void ClearRegister(int reg) = 0;
   virtual void WriteStackPointerToRegister(int reg) = 0;
 
  private: