Leverage Lasse's StringSearch object to speed up calculations of script ...

src/handles.cc

 // Copyright 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 18 matching lines @@
 
 #include "accessors.h"
 #include "api.h"
 #include "arguments.h"
 #include "bootstrapper.h"
 #include "compiler.h"
 #include "debug.h"
 #include "execution.h"
 #include "global-handles.h"
 #include "natives.h"
+#include "string-search.h"
 #include "runtime.h"
 #include "stub-cache.h"
 
 namespace v8 {
 namespace internal {
 
 
 v8::ImplementationUtilities::HandleScopeData HandleScope::current_ =
     { NULL, NULL, 0 };
 
@@ skipping 448 matching lines @@
 
   Handle<String> src(String::cast(script->source()));
 
   Handle<FixedArray> array = CalculateLineEnds(src, true);
 
   script->set_line_ends(*array);
   ASSERT(script->line_ends()->IsFixedArray());
 }
 
 
-Handle<FixedArray> CalculateLineEnds(Handle<String> src,
-                                     bool with_imaginary_last_new_line) {
-  const int src_len = src->length();
-  Handle<String> new_line = Factory::NewStringFromAscii(CStrVector("\n"));
+template <typename SourceChar>
+Handle<FixedArray> CalculateLineEnds(Vector<const SourceChar> src,

[mnaganov (inactive), 2010/11/17 15:32:00]

Please mark this private function 'static'.

[sandholm, 2010/11/17 15:45:23]

Done.

+                                     bool with_last_line) {
+  const int src_len = src.length();
+  StringSearch<char, SourceChar> search(CStrVector("\n"));
 
   // Pass 1: Identify line count.
   int line_count = 0;
   int position = 0;
   while (position != -1 && position < src_len) {
-    position = Runtime::StringMatch(src, new_line, position);
+    position = search.Search(src, position);
     if (position != -1) {
       position++;
-    }
-    if (position != -1) {
       line_count++;
-    } else if (with_imaginary_last_new_line) {
+    } else if (with_last_line) {
       // Even if the last line misses a line end, it is counted.
       line_count++;
     }
   }
 
   // Pass 2: Fill in line ends positions
   Handle<FixedArray> array = Factory::NewFixedArray(line_count);
   int array_index = 0;
   position = 0;
   while (position != -1 && position < src_len) {
-    position = Runtime::StringMatch(src, new_line, position);
+    position = search.Search(src, position);
     if (position != -1) {
       array->set(array_index++, Smi::FromInt(position++));
-    } else if (with_imaginary_last_new_line) {
+    } else if (with_last_line) {
       // If the script does not end with a line ending add the final end
       // position as just past the last line ending.
       array->set(array_index++, Smi::FromInt(src_len));
     }
   }
   ASSERT(array_index == line_count);
 
   return array;
 }
 
+Handle<FixedArray> CalculateLineEnds(Handle<String> src,
+                                     bool with_last_line) {
+  // const int src_len = src->length();
+  if (!src->IsFlat()) FlattenString(src);
+  AssertNoAllocation no_heap_allocation;  // ensure vectors stay valid
+  // Extract flattened substrings of cons strings before determining asciiness.
+  String* seq_src = *src;
+  if (seq_src->IsConsString()) seq_src = ConsString::cast(seq_src)->first();

[mnaganov (inactive), 2010/11/17 15:32:00]

Should you assert anything about the second part of cons string? Must it be
empty or something?

[sandholm, 2010/11/17 15:45:23]

Yes. src is flat so if it is a cons string then the second part must be empty.

+  // dispatch on type of strings
+  if (seq_src->IsAsciiRepresentation()) {
+    return CalculateLineEnds(seq_src->ToAsciiVector(), with_last_line);
+  }
+  return CalculateLineEnds(seq_src->ToUC16Vector(), with_last_line);
+}
+
 
 // Convert code position into line number.
 int GetScriptLineNumber(Handle<Script> script, int code_pos) {
   InitScriptLineEnds(script);
   AssertNoAllocation no_allocation;
   FixedArray* line_ends_array = FixedArray::cast(script->line_ends());
   const int line_ends_len = line_ends_array->length();
 
   if (!line_ends_len)
     return -1;
@@ skipping 307 matching lines @@
 
 OptimizedObjectForAddingMultipleProperties::
 ~OptimizedObjectForAddingMultipleProperties() {
   // Reoptimize the object to allow fast property access.
   if (has_been_transformed_) {
     TransformToFastProperties(object_, unused_property_fields_);
   }
 }
 
 } }  // namespace v8::internal