Irregexp: Added derived knowledge of whether we are at the start of input.

src/ast.cc

 // Copyright 2006-2008 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 232 matching lines @@
   return body()->CaptureRegisters();
 }
 
 
 bool RegExpAssertion::IsAnchored() {
   return type() == RegExpAssertion::START_OF_INPUT;
 }
 
 
 bool RegExpAlternative::IsAnchored() {
-  return this->nodes()->at(0)->IsAnchored();
+  ZoneList<RegExpTree*>* nodes = this->nodes();
+  for (int i = 0; i < nodes->length(); i++) {
+    RegExpTree* node = nodes->at(i);
+    if (node->IsAnchored()) { return true; }
+    if (node->max_match() > 0) { return false; }
+  }
+  return false;
 }
 
 
 bool RegExpDisjunction::IsAnchored() {
   ZoneList<RegExpTree*>* alternatives = this->alternatives();
   for (int i = 0; i < alternatives->length(); i++) {
     if (!alternatives->at(i)->IsAnchored())
       return false;
   }
   return true;
@@ skipping 207 matching lines @@
     if (kInfinity - max_match_ < node_max_match) {
       max_match_ = kInfinity;
     } else {
       max_match_ += node->max_match();
     }
   }
 }
 
 
 } }  // namespace v8::internal