Use finite-length end-anchored regexps to reduce part of regexp that is searched.

src/ast.cc

 // Copyright 2010 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 380 matching lines @@
   Interval self(StartRegister(index()), EndRegister(index()));
   return self.Union(body()->CaptureRegisters());
 }
 
 
 Interval RegExpQuantifier::CaptureRegisters() {
   return body()->CaptureRegisters();
 }
 
 
-bool RegExpAssertion::IsAnchored() {
+bool RegExpAssertion::IsAnchoredAtStart() {
   return type() == RegExpAssertion::START_OF_INPUT;
 }
 
 
-bool RegExpAlternative::IsAnchored() {
+bool RegExpAssertion::IsAnchoredAtEnd() {
+  return type() == RegExpAssertion::END_OF_INPUT;
+}
+
+
+bool RegExpAlternative::IsAnchoredAtStart() {
   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->IsAnchoredAtStart()) { return true; }
     if (node->max_match() > 0) { return false; }
   }
   return false;
 }
 
 
-bool RegExpDisjunction::IsAnchored() {
+bool RegExpAlternative::IsAnchoredAtEnd() {
+  ZoneList<RegExpTree*>* nodes = this->nodes();
+  for (int i = nodes->length() - 1; i >= 0; i--) {
+    RegExpTree* node = nodes->at(i);
+    if (node->IsAnchoredAtEnd()) { return true; }
+    if (node->max_match() > 0) { return false; }
+  }
+  return false;
+}
+
+
+bool RegExpDisjunction::IsAnchoredAtStart() {
   ZoneList<RegExpTree*>* alternatives = this->alternatives();
   for (int i = 0; i < alternatives->length(); i++) {
-    if (!alternatives->at(i)->IsAnchored())
+    if (!alternatives->at(i)->IsAnchoredAtStart())
       return false;
   }
   return true;
 }
 
 
-bool RegExpLookahead::IsAnchored() {
-  return is_positive() && body()->IsAnchored();
+bool RegExpDisjunction::IsAnchoredAtEnd() {
+  ZoneList<RegExpTree*>* alternatives = this->alternatives();
+  for (int i = 0; i < alternatives->length(); i++) {
+    if (!alternatives->at(i)->IsAnchoredAtEnd())
+      return false;
+  }
+  return true;
 }
 
 
-bool RegExpCapture::IsAnchored() {
-  return body()->IsAnchored();
+bool RegExpLookahead::IsAnchoredAtStart() {
+  return is_positive() && body()->IsAnchoredAtStart();
 }
 
 
+bool RegExpCapture::IsAnchoredAtStart() {
+  return body()->IsAnchoredAtStart();
+}
+
+
+bool RegExpCapture::IsAnchoredAtEnd() {
+  return body()->IsAnchoredAtEnd();
+}
+
+
 // Convert regular expression trees to a simple sexp representation.
 // This representation should be different from the input grammar
 // in as many cases as possible, to make it more difficult for incorrect
 // parses to look as correct ones which is likely if the input and
 // output formats are alike.
 class RegExpUnparser: public RegExpVisitor {
  public:
   RegExpUnparser();
   void VisitCharacterRange(CharacterRange that);
   SmartPointer<const char> ToString() { return stream_.ToCString(); }
@@ skipping 195 matching lines @@
       cond_(NULL),
       may_have_function_literal_(true) {
 }
 
 
 CaseClause::CaseClause(Expression* label, ZoneList<Statement*>* statements)
     : label_(label), statements_(statements) {
 }
 
 } }  // namespace v8::internal