Bug 224072 – Introduce LexicalScopeFeatures to enable future bytecode optimizations

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Alexey Shvayka]

Introduce LexicalScopeFeatures to enable future bytecode optimizations

[Alexey Shvayka]

Created attachment 424944 [details]
Patch

[Alexey Shvayka]

Created attachment 425040 [details]
Patch

Fix --debug build and make LexicalScopeFeatures constructor / static methods explicit.

[Keith Miller]

Comment on attachment 425040 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=425040&action=review

r=me with some nits.

> Source/JavaScriptCore/ChangeLog:9
> +        statement, direct `eval`, or certain variable names only within the current executable:

Typo: "to reason about" => "of reasoning about" and "of with statement" => "of with statements"

> Source/JavaScriptCore/ChangeLog:27
> +        If ResolveNode would know that unforgeable global properties are not shadowed and there

Nit: "would know" => "knew"

> Source/JavaScriptCore/bytecode/UnlinkedFunctionExecutable.h:257
>      unsigned m_firstLineOffset : 31;

This probably shouldn't be a bit field or other bit fields should be shuffled around to repack the struct.

[Radar WebKit Bug Importer]

<rdar://problem/76366251>

[Alexey Shvayka]

Created attachment 430502 [details]
Patch

Update ChangeLog, drop OptionSet to align with other features and use bit fields, add LexicalScopeFeatures to more classes, remove now unused StrictModeFeature and ArrowFunctionContextFeature, and fix bit fields packing.

[Alexey Shvayka]

(In reply to Alexey Shvayka from comment #5)
> Created attachment 430502 [details]
> Patch

                                 sizeof (r278401)   sizeof (patch)

UnlinkedCodeBlock                      160              160
UnlinkedFunctionExecutable              96               96
ScopeNode                              304              304
FunctionMetadataNode                   144              144
SourceProviderCacheItem                 32               32
CachedCodeBlock                        464              464
CachedFunctionExecutableMetadata         4                4
ScriptExecutable                        72               72

[Alexey Shvayka]

Created attachment 430507 [details]
Patch

Fix --debug build.

[EWS]

Committed r278588 (238578@main): <https://commits.webkit.org/238578@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 430507 [details].