[gn] Use exec_script_allowlist in //llvm/utils/gn/.gn

[dpranke]

Use exec_script_allowlist in //llvm/utils/gn/.gn

GN is moving to use exec_script_allowlist instead of exec_script_whitelist everywhere.

See crbug.com/389986807

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[zmodem]

I see the new spelling was added in January (https://gn.googlesource.com/gn/+/ed1abc107815210dc66ec439542bee2f6cbabc00), so this requires a fairly recent version of gn. I don't know if that's a problem for people or not.

Anyway, @nico knows the gn build best.

[nico]

lg, but please give me a bit to update the bots.

Do you want to update the comment right above too?

Could you also update

llvm-project/llvm/utils/gn/build/toolchain/BUILD.gn

Line 86 in 783201b

assert(gn_version >= 1693,

? (Move it to top of file; update comment.)

Another idea could be to assign to one or the other depending on gn_version.

But I think fairly few people use this build, and it's fairly easy to update GN (just run llvm/utils/gn/get.py), so I think it's fine to just require a new(ish) version of GN.

[nico]

Thanks, looks great! I'll land this some time today, after making sure my bots have a new-enough GN.

[nico]

Do you want to update the comment right above too?

(Looks like this wasn't done yet.)

[dpranke]

Do you want to update the comment right above too?

(Looks like this wasn't done yet.)

Whoops. Fixed.

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[nico]

Hm, looks like the assert runs too late. On a machine where I hadn't bumped GN yet, I'm getting

ERROR at //.gn:9:25: Assignment had no effect.
exec_script_allowlist = []
                        ^
You set the variable "exec_script_allowlist" here and it was unused before it went
out of scope.

Ah well. If anyone runs into this, running llvm/utils/gn/get.py makes it go away.

[dpranke]

Yeah, the dotfile is processed before the other files, so I'm not surprised.