String search performance improvements:

src/runtime.cc

 // Copyright 2006-2009 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 2335 matching lines @@
   }
 
   return -1;
 }
 
 
 template <typename schar>
 static inline int SingleCharIndexOf(Vector<const schar> string,
                                     schar pattern_char,
                                     int start_index) {
+  if (sizeof(schar) == 1) {
+    schar* pos = reinterpret_cast<schar*>(
+        memchr(string.start() + start_index,
+               pattern_char,
+               string.length() - start_index));
+    if (pos == NULL) return -1;
+    return pos - string.start();
+  }
   for (int i = start_index, n = string.length(); i < n; i++) {
     if (pattern_char == string[i]) {
       return i;
     }
   }
   return -1;
 }
 
 
 template <typename schar>
@@ skipping 27 matching lines @@
 
   // We know our pattern is at least 2 characters, we cache the first so
   // the common case of the first character not matching is faster.
   pchar pattern_first_char = pattern[0];
   for (int i = idx, n = subject.length() - pattern.length(); i <= n; i++) {
     badness++;
     if (badness > 0) {
       *complete = false;
       return i;
     }
-    if (subject[i] != pattern_first_char) continue;
+    if (sizeof(schar) == 1 && sizeof(pchar) == 1) {
+      schar* pos = reinterpret_cast<schar*>(memchr(subject.start() + i,
+                                                   pattern_first_char,
+                                                   n - i + 1));
+      if (pos == NULL) {
+        *complete = true;
+        return -1;
+      }
+      i = pos - subject.start();
+    } else {
+      if (subject[i] != pattern_first_char) continue;
+    }
     int j = 1;
     do {
       if (pattern[j] != subject[i+j]) {
         break;
       }
       j++;
     } while (j < pattern.length());
     if (j == pattern.length()) {
       *complete = true;
       return i;
     }
     badness += j;
   }
   *complete = true;
   return -1;
 }
 
 // Simple indexOf that never bails out. For short patterns only.
 template <typename pchar, typename schar>
 static int SimpleIndexOf(Vector<const schar> subject,
                          Vector<const pchar> pattern,
                          int idx) {
   pchar pattern_first_char = pattern[0];
   for (int i = idx, n = subject.length() - pattern.length(); i <= n; i++) {
-    if (subject[i] != pattern_first_char) continue;
+    if (sizeof(schar) == 1 && sizeof(pchar) == 1) {
+      schar* pos = reinterpret_cast<schar*>(memchr(subject.start() + i,
+                                                   pattern_first_char,
+                                                   n - i + 1));
+      if (pos == NULL) return -1;
+      i = pos - subject.start();
+    } else {
+      if (subject[i] != pattern_first_char) continue;
+    }
     int j = 1;
     do {
       if (pattern[j] != subject[i+j]) {
         break;
       }
       j++;
     } while (j < pattern.length());
     if (j == pattern.length()) {
       return i;
     }
@@ skipping 6934 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal