1544852 - ScopeData destructors are not called

Status: RESOLVED FIXED

(Core :: JavaScript: GC, task)

Description

[Jon Coppeard (:jonco)]

When scopes are finalized their data is freed rather than deleted, as follows:

void Scope::finalize(FreeOp* fop) {
  MOZ_ASSERT(CurrentThreadIsGCSweeping());
  if (data_) {
    // We don't need to call the destructors for any GCPtrs in Data because
    // this only happens during a GC.
    fop->free_(data_);
    data_ = nullptr;
  }
}

This seems pretty dubious. At the very least we want GCPtr destructors to run in debug builds because they have assertions that we would like checked. (It is true that GCPtr destructors do nothing in release builds).

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1544852 - Call scope data destructors r=tcampbell?

The patch casts the base class pointer to the correct type and deletes it. Happily very little code (~20 instructions) is generated in opt builds where these destructors are basically no-ops.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/e3cd7a936c71
Call scope data destructors from the finalizer r=tcampbell

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

The bot thinks this bug is a task, but please change it back in case of error.

Comment 4

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/e3cd7a936c71