Add support for \b and ^ and $ in multiline mode, completing Irregexp...

src/regexp-macro-assembler.h

 // Copyright 2008 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
@@ skipping 43 matching lines @@
   // 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;
+  virtual void CheckAtStart(Label* on_at_start) = 0;
   // Check the current character against a bitmap.  The range of the current
   // character must be from start to start + length_of_bitmap_in_bits.
   virtual void CheckBitmap(
       uc16 start,           // The bitmap is indexed from this character.
       Label* bitmap,        // Where the bitmap is emitted.
       Label* on_zero) = 0;  // Where to go if the bit is 0.  Fall through on 1.
   // Dispatch after looking the current character up in a 2-bits-per-entry
   // map.  The destinations vector has up to 4 labels.
   virtual void CheckCharacter(uint32_t c, Label* on_equal) = 0;
   // Bitwise and the current character with the given constant and then
@@ skipping 136 matching lines @@
   ArraySlice GetBuffer(Vector<T> values);
  private:
   size_t byte_array_size_;
   Handle<ByteArray> current_byte_array_;
   int current_byte_array_free_offset_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_REGEXP_MACRO_ASSEMBLER_H_