Removed dangerous Factory::NewUninitializedFixedArray.

Removed dangerous Factory::NewUninitializedFixedArray.

This was used in runtime StringToArray function which I simplified
keeping its performance for ascii strings.

Committed: http://code.google.com/p/v8/source/detail?r=4035

[Mads Ager (chromium), 2010-03-05 12:17:16]

LGTM, thanks!

http://codereview.chromium.org/669156/diff/1/4
File src/runtime.cc (right):

http://codereview.chromium.org/669156/diff/1/4#newcode4263
src/runtime.cc:4263: FixedArray* raw_elements = FixedArray::cast(obj);
Let's put elements in a handle right away here and pass *elements to
CopyCachedAsciiCharsToArray.

[antonm, 2010-03-05 12:18:05]

LGTM

http://codereview.chromium.org/669156/diff/1/4
File src/runtime.cc (right):

http://codereview.chromium.org/669156/diff/1/4#newcode4234
src/runtime.cc:4234: if (i < length) {
maybe lift this filling into the loop itself:

if (value == undefined) {
  // fill the rest of array
  return
}

?

http://codereview.chromium.org/669156/diff/1/4#newcode4236
src/runtime.cc:4236: memset(elements->data_start() + i, 0, length - i);
not insisting, but something like Smi::FromInt(0) == 0 might be helpful for next
generations.

http://codereview.chromium.org/669156/diff/1/4#newcode4261
src/runtime.cc:4261: Object* obj =
Heap::AllocateUninitializedFixedArray(length);
maybe add a comment that uninitialized array will never leak into GC?

[Vitaly Repeshko, 2010-03-05 12:32:10]

Thanks for review!
Anton, thanks for spotting this!

This is now submitted.


-- Vitaly

http://codereview.chromium.org/669156/diff/1/4
File src/runtime.cc (right):

http://codereview.chromium.org/669156/diff/1/4#newcode4234
src/runtime.cc:4234: if (i < length) {
On 2010/03/05 12:18:05, antonm wrote:
> maybe lift this filling into the loop itself:
> 
> if (value == undefined) {
>   // fill the rest of array
>   return
> }
> 
> ?

I'd like to keep the fast loop as simple as possible to avoid confusing the poor
compiler.

http://codereview.chromium.org/669156/diff/1/4#newcode4236
src/runtime.cc:4236: memset(elements->data_start() + i, 0, length - i);
On 2010/03/05 12:18:05, antonm wrote:
> not insisting, but something like Smi::FromInt(0) == 0 might be helpful for
next
> generations.

Done.

http://codereview.chromium.org/669156/diff/1/4#newcode4261
src/runtime.cc:4261: Object* obj =
Heap::AllocateUninitializedFixedArray(length);
On 2010/03/05 12:18:05, antonm wrote:
> maybe add a comment that uninitialized array will never leak into GC?

Done.

http://codereview.chromium.org/669156/diff/1/4#newcode4263
src/runtime.cc:4263: FixedArray* raw_elements = FixedArray::cast(obj);
On 2010/03/05 12:17:16, Mads Ager wrote:
> Let's put elements in a handle right away here and pass *elements to
> CopyCachedAsciiCharsToArray.

Done.