Avoids allocating a JSArray of capture information on each non-global...

src/jsregexp.h

Index: src/jsregexp.h
===================================================================
--- src/jsregexp.h	(revision 1374)
+++ src/jsregexp.h	(working copy)
@@ -59,13 +59,15 @@
   // This function calls the garbage collector if necessary.
   static Handle<Object> Exec(Handle<JSRegExp> regexp,
                              Handle<String> subject,
-                             Handle<Object> index);
+                             Smi* index,
+                             Handle<JSArray> lastMatchInfo);
 
   // Call RegExp.prototyp.exec(string) in a loop.
   // Used by String.prototype.match and String.prototype.replace.
   // This function calls the garbage collector if necessary.
   static Handle<Object> ExecGlobal(Handle<JSRegExp> regexp,
-                                   Handle<String> subject);
+                                   Handle<String> subject,
+                                   Handle<JSArray> lastMatchInfo);
 
   // Prepares a JSRegExp object with Irregexp-specific data.
   static Handle<Object> IrregexpPrepare(Handle<JSRegExp> re,
@@ -79,18 +81,22 @@
                                     Handle<String> match_pattern);
   static Handle<Object> AtomExec(Handle<JSRegExp> regexp,
                                  Handle<String> subject,
-                                 Handle<Object> index);
+                                 Smi* index,
+                                 Handle<JSArray> lastMatchInfo);
 
   static Handle<Object> AtomExecGlobal(Handle<JSRegExp> regexp,
-                                       Handle<String> subject);
+                                       Handle<String> subject,
+                                       Handle<JSArray> lastMatchInfo);
 
   // Execute an Irregexp bytecode pattern.
   static Handle<Object> IrregexpExec(Handle<JSRegExp> regexp,
                                      Handle<String> subject,
-                                     Handle<Object> index);
+                                     Smi* index,
+                                     Handle<JSArray> lastMatchInfo);
 
   static Handle<Object> IrregexpExecGlobal(Handle<JSRegExp> regexp,
-                                           Handle<String> subject);
+                                           Handle<String> subject,
+                                           Handle<JSArray> lastMatchInfo);
 
   static void NewSpaceCollectionPrologue();
   static void OldSpaceCollectionPrologue();
@@ -107,6 +113,30 @@
   static const int kIrregexpCodeIndex = 3;
   static const int kIrregexpDataLength = 4;
 
+  // Offsets in the lastMatchInfo array.
+  static const int kLastCaptureCount = 0;
+  static const int kLastSubject = 1;
+  static const int kLastInput = 2;
+  static const int kFirstCapture = 1;
+  static const int kLastMatchOverhead = 3;
+  static int GetCapture(FixedArray* array, int index) {
+    return Smi::cast(array->get(index + kFirstCapture))->value();
+  }
+  static void SetLastCaptureCount(FixedArray* array, int to) {
+    array->set(kLastCaptureCount, Smi::FromInt(to));
+  }
+  static void SetLastSubject(FixedArray* array, String* to) {
+    int capture_count = GetLastCaptureCount(array);
+    array->set(capture_count + kLastSubject, to);
+  }
+  static void SetLastInput(FixedArray* array, String* to) {
+    int capture_count = GetLastCaptureCount(array);
+    array->set(capture_count + kLastInput, to);
+  }
+  static void SetCapture(FixedArray* array, int index, int to) {
+    array->set(index + kFirstCapture, Smi::FromInt(to));
+  }
+
  private:
   static String* last_ascii_string_;
   static String* two_byte_cached_string_;
@@ -121,6 +151,7 @@
   // Returns an empty handle in case of an exception.
   static Handle<Object> IrregexpExecOnce(Handle<FixedArray> regexp,
                                          int num_captures,
+                                         Handle<JSArray> lastMatchInfo,
                                          Handle<String> subject16,
                                          int previous_index,
                                          int* ovector,
@@ -134,6 +165,10 @@
                               int character_position,
                               int utf8_position);
 
+  // Used to access the lastMatchInfo array.
+  static int GetLastCaptureCount(FixedArray* array) {
+    return Smi::cast(array->get(kLastCaptureCount))->value();
+  }
   // A one element cache of the last utf8_subject string and its length.  The
   // subject JS String object is cached in the heap.  We also cache a
   // translation between position and utf8 position.