Reviewers: William Hesse,
Description:
Double allocation size for special json strings on every resize (fixes
crbug 83877)
The issue was that with the relatively small start and increment size of the
string we created a ton of string handles when scanning a large string with
special characters (500k+ in this case).
In addition, since we can not be sure the the newly allocated string
is in newspace a check is introduced and if not a filler object is
inserted instead of shrinking.
Please review this at http://codereview.chromium.org/7075009/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/json-parser.h
M src/json-parser.cc
Index: src/json-parser.cc
===================================================================
--- src/json-parser.cc (revision 8071)
+++ src/json-parser.cc (working copy)
@@ -380,7 +380,7 @@
while (c0_ != '"') {
// Create new seq string
if (count >= kInitialSpecialStringSize * allocation_count) {
- allocation_count++;
+ allocation_count = allocation_count * 2;
int new_size = allocation_count * kInitialSpecialStringSize;
Handle<String> new_two_byte =
isolate()->factory()->NewRawTwoByteString(new_size,
@@ -443,10 +443,18 @@
Advance();
// Shrink the the string to our length.
- isolate()->heap()->
- new_space()->
- ShrinkStringAtAllocationBoundary<SeqTwoByteString>(*seq_two_byte,
- count);
+ if (isolate()->heap()->InNewSpace(*seq_two_byte)) {
+ isolate()->heap()->new_space()->
+ ShrinkStringAtAllocationBoundary<SeqTwoByteString>(*seq_two_byte,
+ count);
+ } else {
+ int string_size = SeqTwoByteString::SizeFor(count);
+ int allocated_string_size =
+ SeqTwoByteString::SizeFor(kInitialSpecialStringSize *
allocation_count);
+ int delta = allocated_string_size - string_size;
+ Address start_filler_object = seq_two_byte->address() + delta;
+ isolate()->heap()->CreateFillerObjectAt(start_filler_object, delta);
+ }
string_val_ = isolate()->factory()->NewConsString(ascii, seq_two_byte);
return Token::STRING;
}
Index: src/json-parser.h
===================================================================
--- src/json-parser.h (revision 8071)
+++ src/json-parser.h (working copy)
@@ -135,7 +135,7 @@
int end_pos;
};
- static const int kInitialSpecialStringSize = 100;
+ static const int kInitialSpecialStringSize = 1024;
private:
--
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