External string table.

External string table.

Instead of weak handles external strings use a separate table.  This
table uses 5 times less memory than weak handles.  Moreover, since we
don't have to follow the weak handle callback protocol we can collect
the strings faster and even on scavenge collections.

[Mads Ager (chromium), 2009-12-08 16:18:40]

LGTM!

http://codereview.chromium.org/467037/diff/1/7
File src/heap.cc (right):

http://codereview.chromium.org/467037/diff/1/7#newcode4060
src/heap.cc:4060: List<Object*>& target = new_to_old ? old_space_strings_ :
new_space_strings_;
Use old_space_strings_ as the target always?  It should be completely clear that
this can only ever move from the new space list to the old space list.

It might be clearer to remove the bool parameter and just iterate
new_space_strings first and then iterate old_space_strings?  It is a bit more
code, but I think it would be clearer and it would remove checking for new space
for old_space_strings.

[Vitaly Repeshko, 2009-12-09 14:33:23]

Thanks! Submitted.


-- Vitaly

http://codereview.chromium.org/467037/diff/1/7
File src/heap.cc (right):

http://codereview.chromium.org/467037/diff/1/7#newcode4060
src/heap.cc:4060: List<Object*>& target = new_to_old ? old_space_strings_ :
new_space_strings_;
On 2009/12/08 16:18:40, Mads Ager wrote:
> Use old_space_strings_ as the target always?  It should be completely clear
that
> this can only ever move from the new space list to the old space list.
> 
> It might be clearer to remove the bool parameter and just iterate
> new_space_strings first and then iterate old_space_strings?  It is a bit more
> code, but I think it would be clearer and it would remove checking for new
space
> for old_space_strings.

Makes sense. Done.