Introduce builtin for Array.unshift function.

Introduce builtin for Array.unshift function.

Committed: http://code.google.com/p/v8/source/detail?r=3859

[antonm, 2010-02-15 10:46:31]

Mads, may you have look at this one?

There is still place for improvements both minimal (like faster copying and rset
management) and more dramatical (like reversed arrays to get rid of copying
altogether).

[Mads Ager (chromium), 2010-02-15 11:23:41]

LGTM

Please make sure that we have test cases for the different cases as for
Array.prototype.shift.

http://codereview.chromium.org/600124/diff/2001/3002
File src/builtins.cc (right):

http://codereview.chromium.org/600124/diff/2001/3002#newcode251
src/builtins.cc:251: if (to_add == 0)
Please either use one-liner or use braces around the body.

http://codereview.chromium.org/600124/diff/2001/3002#newcode318
src/builtins.cc:318: FixedArray* elms, JSObject* prototype) {
Please use one-parameter per line indentation here.

http://codereview.chromium.org/600124/diff/2001/3002#newcode366
src/builtins.cc:366: if (to_add == 0)
Braces or one-liner.

http://codereview.chromium.org/600124/diff/2001/3002#newcode399
src/builtins.cc:399: for (int index = 0; index < len; index++) {
Just use 'i' as above?

http://codereview.chromium.org/600124/diff/2001/3002#newcode409
src/builtins.cc:409: for (int index = 0; index < to_add; index++) {
Just use 'i' as above?

[antonm, 2010-02-15 13:21:10]

I've spotted one bug in my code---one cannot leave early from unshift with no
args as it still should get elements from prototypes.  I checked that current
Chromium works this way.

If you think there should be more tests, just let me know.

http://codereview.chromium.org/600124/diff/2001/3002
File src/builtins.cc (right):

http://codereview.chromium.org/600124/diff/2001/3002#newcode251
src/builtins.cc:251: if (to_add == 0)
On 2010/02/15 11:23:41, Mads Ager wrote:
> Please either use one-liner or use braces around the body.

Done.

http://codereview.chromium.org/600124/diff/2001/3002#newcode318
src/builtins.cc:318: FixedArray* elms, JSObject* prototype) {
On 2010/02/15 11:23:41, Mads Ager wrote:
> Please use one-parameter per line indentation here.

Done.

http://codereview.chromium.org/600124/diff/2001/3002#newcode366
src/builtins.cc:366: if (to_add == 0)
On 2010/02/15 11:23:41, Mads Ager wrote:
> Braces or one-liner.

Done.

http://codereview.chromium.org/600124/diff/2001/3002#newcode399
src/builtins.cc:399: for (int index = 0; index < len; index++) {
On 2010/02/15 11:23:41, Mads Ager wrote:
> Just use 'i' as above?

Done.

http://codereview.chromium.org/600124/diff/2001/3002#newcode409
src/builtins.cc:409: for (int index = 0; index < to_add; index++) {
On 2010/02/15 11:23:41, Mads Ager wrote:
> Just use 'i' as above?

Done.

[Mads Ager (chromium), 2010-02-15 13:25:51]

LGTM, good catch.