Add TypedArray.from method

Add TypedArray.from method

This function creates a new way to make TypedArrays based on existing
iterable or Array-like objects, analogous to Array.from. The patch
implements the function and adds tests.

R=arv@chromium.org
BUG=v8:3578
LOG=Y

Committed: https://crrev.com/cc3f59db556efe4e31813326510730cccafe801b
Cr-Commit-Position: refs/heads/master@{#28456}

[arv (Not doing code reviews), 2015-05-15 00:20:23]

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js
File src/harmony-typedarray.js (right):

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:104: // TODO(dehrenberg): This is an approximation of
the spec, which requires
I thought you wanted littledan?

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:106: if (!IS_SPEC_OBJECT(constructor) ||
constructor.prototype === undefined ||
Use IS_UNDEFINED since undefined can be redefined.

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:107: !%HasOwnProperty(constructor.prototype,
"BYTES_PER_ELEMENT"))
Use {}

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:119: var array = $arrayFrom.call(global.Array, source,
mapfn, thisArg);
Please add 

var GlobalArray = global.Array;

to the top since Array can be redefined.

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:119: var array = $arrayFrom.call(global.Array, source,
mapfn, thisArg);
Use %_CallFunction since Function.prototype.call can be redefined.

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:119: var array = $arrayFrom.call(global.Array, source,
mapfn, thisArg);
Is global.Array correct here? Shouldn't Uint8Array.from(new Set([1, 2, 3])
create a new Uint8Array?

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:127: "from", TypedArrayFrom,
This needs one more object in the [[Prototype]] chain:

Uint8Array.__proto__ === %TypedArray%
%TypedArray%.__proto__ === %FunctionPrototype%

http://people.mozilla.org/~jorendorff/es6-draft.html#sec-properties-of-the-ty...

Maybe add a todo and reference the bug we already have on this?

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
File test/mjsunit/harmony/typedarray-from.js (right):

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:16: Float64Array];
] on next line

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:18:
typedArrayConstructors.forEach(function(constructor) {
I find for-of loops easier to read

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:20: assertEquals(1,
constructor.from.length);
indent

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:25: var construct_fn =
constructor.construct;
Where did construct come from?

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:28: assertInstanceof(value, type);
I tend to prefer to check the __proto__ or Object.getPrototypeOf since it is
more exact. Checking instanceof does not care if there are extra object in the
prototype chain.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:30: for (var i=0; i<value.length; ++i) {
ws around binops

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:38: function non_strict(){
assertEquals(global, this); }
ws before {

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:39: function strict(){ "use strict";
assertEquals(void 0, this); }
you can use undefined in tests if you want

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:58: { length: 1, '0': 5 }), [5],
constructor);
no need to quote the key here.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:82: assertThrows(function() {
constructor.from([], "noncallable"); },
stick to either " or '

[dehrenberg, 2015-05-15 23:39:15]

These should all be fixed in v2.

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js
File src/harmony-typedarray.js (right):

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:104: // TODO(dehrenberg): This is an approximation of
the spec, which requires
On 2015/05/15 00:20:22, arv wrote:
> I thought you wanted littledan?

Done.

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:106: if (!IS_SPEC_OBJECT(constructor) ||
constructor.prototype === undefined ||
On 2015/05/15 00:20:22, arv wrote:
> Use IS_UNDEFINED since undefined can be redefined.

Done.

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:107: !%HasOwnProperty(constructor.prototype,
"BYTES_PER_ELEMENT"))
On 2015/05/15 00:20:22, arv wrote:
> Use {}

Done.

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:119: var array = $arrayFrom.call(global.Array, source,
mapfn, thisArg);
On 2015/05/15 00:20:22, arv wrote:
> Is global.Array correct here? Shouldn't Uint8Array.from(new Set([1, 2, 3])
> create a new Uint8Array?

I'm first making an array with the contents and then making a TypedArray with
that in it.

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:119: var array = $arrayFrom.call(global.Array, source,
mapfn, thisArg);
On 2015/05/15 00:20:22, arv wrote:
> Please add 
> 
> var GlobalArray = global.Array;
> 
> to the top since Array can be redefined.

Done.

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:119: var array = $arrayFrom.call(global.Array, source,
mapfn, thisArg);
On 2015/05/15 00:20:22, arv wrote:
> Use %_CallFunction since Function.prototype.call can be redefined.

Done.

https://codereview.chromium.org/1132163011/diff/1/src/harmony-typedarray.js#n...
src/harmony-typedarray.js:127: "from", TypedArrayFrom,
On 2015/05/15 00:20:22, arv wrote:
> This needs one more object in the [[Prototype]] chain:
> 
> Uint8Array.__proto__ === %TypedArray%
> %TypedArray%.__proto__ === %FunctionPrototype%
> 
>
http://people.mozilla.org/~jorendorff/es6-draft.html#sec-properties-of-the-ty...
> 
> Maybe add a todo and reference the bug we already have on this?

I have a bug open for this https://code.google.com/p/v8/issues/detail?id=4085 .
Added a reference.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
File test/mjsunit/harmony/typedarray-from.js (right):

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:16: Float64Array];
On 2015/05/15 00:20:22, arv wrote:
> ] on next line

Done.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:18:
typedArrayConstructors.forEach(function(constructor) {
On 2015/05/15 00:20:22, arv wrote:
> I find for-of loops easier to read

Done.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:20: assertEquals(1,
constructor.from.length);
On 2015/05/15 00:20:22, arv wrote:
> indent

Done.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:25: var construct_fn =
constructor.construct;
On 2015/05/15 00:20:22, arv wrote:
> Where did construct come from?

Oops, this was a remnant for a test that I deleted, and it was supposed to read
constructor.constructor.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:28: assertInstanceof(value, type);
On 2015/05/15 00:20:22, arv wrote:
> I tend to prefer to check the __proto__ or Object.getPrototypeOf since it is
> more exact. Checking instanceof does not care if there are extra object in the
> prototype chain.

Done.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:30: for (var i=0; i<value.length; ++i) {
On 2015/05/15 00:20:22, arv wrote:
> ws around binops

Done.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:38: function non_strict(){
assertEquals(global, this); }
On 2015/05/15 00:20:23, arv wrote:
> ws before {

Done.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:39: function strict(){ "use strict";
assertEquals(void 0, this); }
On 2015/05/15 00:20:22, arv wrote:
> you can use undefined in tests if you want

Done.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:58: { length: 1, '0': 5 }), [5],
constructor);
On 2015/05/15 00:20:22, arv wrote:
> no need to quote the key here.

Done.

https://codereview.chromium.org/1132163011/diff/1/test/mjsunit/harmony/typeda...
test/mjsunit/harmony/typedarray-from.js:82: assertThrows(function() {
constructor.from([], "noncallable"); },
On 2015/05/15 00:20:22, arv wrote:
> stick to either " or '

Done.

[arv (Not doing code reviews), 2015-05-16 18:23:45]

https://codereview.chromium.org/1132163011/diff/20001/src/harmony-typedarray.js
File src/harmony-typedarray.js (right):

https://codereview.chromium.org/1132163011/diff/20001/src/harmony-typedarray....
src/harmony-typedarray.js:121: var array = %_CallFunction(GlobalArray, source,
mapfn, thisArg, $arrayFrom);
Add todo. It would surely be better to not have a temporary array.

Can you do the $innerArrayFrom solution here too?

https://codereview.chromium.org/1132163011/diff/20001/test/mjsunit/harmony/ty...
File test/mjsunit/harmony/typedarray-from.js (right):

https://codereview.chromium.org/1132163011/diff/20001/test/mjsunit/harmony/ty...
test/mjsunit/harmony/typedarray-from.js:64: var kSet = new Set([1, 2, 3]);
kSet -> set

https://codereview.chromium.org/1132163011/diff/20001/test/mjsunit/harmony/ty...
test/mjsunit/harmony/typedarray-from.js:103: called = true;
another way to do this is to use a counter and then assert that it is 1
afterwards.

https://codereview.chromium.org/1132163011/diff/20001/test/mjsunit/harmony/ty...
test/mjsunit/harmony/typedarray-from.js:124: 
remove empty line

[dehrenberg, 2015-05-18 17:56:51]

https://codereview.chromium.org/1132163011/diff/20001/src/harmony-typedarray.js
File src/harmony-typedarray.js (right):

https://codereview.chromium.org/1132163011/diff/20001/src/harmony-typedarray....
src/harmony-typedarray.js:121: var array = %_CallFunction(GlobalArray, source,
mapfn, thisArg, $arrayFrom);
On 2015/05/16 18:23:45, arv wrote:
> Add todo. It would surely be better to not have a temporary array.
> 
> Can you do the $innerArrayFrom solution here too?

The problem is that, if the source is iterable, then we don't know its length
until we get all the way through it. So we have to iterate through the whole
thing, and then make a TypedArray of that length. I don't really see an 'inner'
part that I could pull out.
The only way I could see to speed this up would be to implement a TypedVector
(TypedArray supporting a push method) and execute 'from' directly onto that.
This would be a bit of work, and may or may not be faster. I added a todo.

https://codereview.chromium.org/1132163011/diff/20001/test/mjsunit/harmony/ty...
File test/mjsunit/harmony/typedarray-from.js (right):

https://codereview.chromium.org/1132163011/diff/20001/test/mjsunit/harmony/ty...
test/mjsunit/harmony/typedarray-from.js:64: var kSet = new Set([1, 2, 3]);
On 2015/05/16 18:23:45, arv wrote:
> kSet -> set

Done.

https://codereview.chromium.org/1132163011/diff/20001/test/mjsunit/harmony/ty...
test/mjsunit/harmony/typedarray-from.js:103: called = true;
On 2015/05/16 18:23:45, arv wrote:
> another way to do this is to use a counter and then assert that it is 1
> afterwards.

Done. Thanks, that's cleaner.

https://codereview.chromium.org/1132163011/diff/20001/test/mjsunit/harmony/ty...
test/mjsunit/harmony/typedarray-from.js:124: 
On 2015/05/16 18:23:45, arv wrote:
> remove empty line

Done.

[arv (Not doing code reviews), 2015-05-18 18:11:53]

LGTM

[dehrenberg, 2015-05-18 18:52:23]

The CQ bit was checked by dehrenberg@chromium.org

[commit-bot: I haz the power, 2015-05-18 18:53:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1132163011/40001

[commit-bot: I haz the power, 2015-05-18 20:14:03]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-05-18 22:12:19]

Patchset 3 (id:??) landed as
https://crrev.com/cc3f59db556efe4e31813326510730cccafe801b
Cr-Commit-Position: refs/heads/master@{#28456}