Bug 205517 – Make JSString values from literals in a single consistent style

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Darin Adler]

Make JSString values from literals in a single consistent style

[Darin Adler]

Created attachment 386248 [details]
Patch

[Saam Barati]

Comment on attachment 386248 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=386248&action=review

> Source/JavaScriptCore/ChangeLog:15
> +            jsNontrivialString(vm, "literal")

Could we use literal string as template to turn this code into what you did?

[Darin Adler]

Comment on attachment 386248 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=386248&action=review

>> Source/JavaScriptCore/ChangeLog:15
>> +            jsNontrivialString(vm, "literal")
> 
> Could we use literal string as template to turn this code into what you did?

Yes and no.

The two things we need to know:

1) These characters are immortal, so we can point to them instead of copying.
2) The string is not 1 character long.

We can make a function template that takes an array of char. This matches a literal and does not match things like "const char*'. That is what we do in various places like the equalLettersIgnoringASCIICase function template. However, this does not distinguish literals from other arrays of char, nor does it determine that the last character of the array is a NUL.

However, if we were OK with that limitation, then we could deduce the length of the string from the length of the array (subtracting one), and emit the appropriate code for that case.

I don’t think it’s worth it but it’s something I considered.

[Darin Adler]

More accurately: the string is more than 1 character long

[Darin Adler]

Committed r253865: <https://trac.webkit.org/changeset/253865>

[Radar WebKit Bug Importer]

<rdar://problem/58138961>