1606113 - Move JSScript/LazyScript finalization/tracing to js::BaseScript

Status: RESOLVED FIXED

(Core :: JavaScript Engine, task, P1)

Description

[Ted Campbell [:tcampbell]]

The trace/finalize logic should be moved to the BaseScript to prepare for unifying the GC arena.

Care must be taken with side-table data used for JSScripts. We can add a BaseScript::hasBytecode() method that looks for the presence of sharedData_ to determine if side-tables needed to be traced or updated. These side-tables are only used for successfully compiled scripts, so checking for bytecode is a reasonable mechanism.

The script->lazy and lazy->script tracing is not moved to BaseScript because those fields will be removed shortly.

Comment 1

[Ted Campbell [:tcampbell]]

Attachment: Bug 1606113 - Finalize JSScript fields after associated data. r?jandem

Associated tables like DebuggerScripts still need access to bytecode, so make
sure we finalize the script's actual fields last.

Comment 2

[Ted Campbell [:tcampbell]]

Attachment: Bug 1606113 - Move BaseScript::warmUpData tracing/finalizing to BaseScript. r?jandem

The trace logic is already part of BaseScript so move the finalization logic.
Use a down-cast to JSScript now since only JSScripts have bytecode and
JitScripts. This lets us avoid rewriting a lot of helper methods just yet.

Depends on D58300

Comment 3

[Ted Campbell [:tcampbell]]

Attachment: Bug 1606113 - Move BaseScript::sharedData tracing/finalizing to BaseScript. r?jandem

Move the code from JSScript to BaseScript and rename freeScriptData to
freeSharedData.

Depends on D58301

Comment 4

[Ted Campbell [:tcampbell]]

Attachment: Bug 1606113 - Trace/finalize script side-tables from BaseScript. r?jandem

A number of side-tables exist that are keyed by JSScript pointers. This patch
moves the tracing and finalization of these from JSScript to BaseScript to
support combining LazyScript/JSScript GC arena. This patch eliminates the
LazyScript and JSScript finalize method specializations.

A BaseScript::hasBytecode() method is added to determine if a BaseScript was
a JSScript that was successfully compiled with bytecode. Only these scripts
may be used as keys in side-tables so we check this in finalize methods. A
down-cast to JSScript is used once again to avoid rewriting all the accessor
methods yet.

Depends on D58303

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7b0110552618
Finalize JSScript fields after associated data. r=jandem
https://hg.mozilla.org/integration/autoland/rev/96d2a50a56a6
Move BaseScript::warmUpData tracing/finalizing to BaseScript. r=jandem
https://hg.mozilla.org/integration/autoland/rev/33ae0330cbe4
Move BaseScript::sharedData tracing/finalizing to BaseScript. r=jandem
https://hg.mozilla.org/integration/autoland/rev/710e512a7352
Trace/finalize script side-tables from BaseScript. r=jandem

Comment 6

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/7b0110552618
https://hg.mozilla.org/mozilla-central/rev/96d2a50a56a6
https://hg.mozilla.org/mozilla-central/rev/33ae0330cbe4
https://hg.mozilla.org/mozilla-central/rev/710e512a7352