[ES6] DFG and FTL should be aware of that StringConstructor behavior for symbols becomes different from ToString

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Yusuke Suzuki]

In ES6, StringConstructor behavior becomes different from ToString abstract operations in the spec. (and JSValue::toString).

ToString(symbol) throws a type error.
String(symbol) produces  SymbolDescriptiveString(value).

So, in DFG and FTL phase, they should not inline String constructor to ToString.
Now, in the template literals patch, ToString DFG operation is planned to be used for it.
And current ToString behavior is aligned to the spec (and JSValue::toString). I think keeping it is better.
So intead of changing ToString behavior, I think adding StringConstructor operation into DFG and FTL is nice.

[Yusuke Suzuki]

Created attachment 250171 [details]
Patch

[Yusuke Suzuki]

*** Bug 143427 has been marked as a duplicate of this bug. ***

[Joseph Pecoraro]

Comment on attachment 250171 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=250171&action=review

> Source/JavaScriptCore/runtime/StringConstructor.cpp:112
> +        return jsString(exec, asSymbol(argument)->descriptiveString());

Nit: This can be jsNontrivialString, which can be used for Strings guaranteed to be 2 or more characters long, and this is guaranteed to have "Symbol()".

[Yusuke Suzuki]

Comment on attachment 250171 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=250171&action=review

>> Source/JavaScriptCore/runtime/StringConstructor.cpp:112
>> +        return jsString(exec, asSymbol(argument)->descriptiveString());
> 
> Nit: This can be jsNontrivialString, which can be used for Strings guaranteed to be 2 or more characters long, and this is guaranteed to have "Symbol()".

Thank you! I've changed it.

[Yusuke Suzuki]

Created attachment 250182 [details]
Patch

[Geoffrey Garen]

Comment on attachment 250182 [details]
Patch

r=me

[Yusuke Suzuki]

Comment on attachment 250182 [details]
Patch

Thank you for your review :D

[WebKit Commit Bot]

Comment on attachment 250182 [details]
Patch

Clearing flags on attachment: 250182

Committed r182433: <http://trac.webkit.org/changeset/182433>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.