Bug 270699 – [JSC] Add arbitrary label alignment functionality to offlineasm

• Component: JavaScriptCore
• Status: REOPENED

[Max Rottenkolber]

To express some programs like the InPlaceInterpreter we need to align instructions to specific boundaries (such as 256).

We currently to do this via `emit ".balign 256, 0xcc"' (for instance) but this is not reliable on armv7 as its globaladdr implementation can insert code unpredictably (from the point of view of the offlineasm user), hence breaking the alignment.

We should add functionality in offlineasm to address this usecase reliably.

Possibly related to rdar://113594783

[EWS]

Committed 276085@main (71f803e6ee62): <https://commits.webkit.org/276085@main>

Reviewed commits have been landed. Closing PR #25628 and removing active labels.

[Radar WebKit Bug Importer]

<rdar://problem/124613758>

[WebKit Commit Bot]

Re-opened since this is blocked by bug 271065

[Mark Lam]

rdar://113594783

[Mark Lam]

*** Bug 272200 has been marked as a duplicate of this bug. ***

[Mark Lam]

Pull request for re-land: https://github.com/WebKit/WebKit/pull/26877

[EWS]

Committed 277134@main (75713dba1787): <https://commits.webkit.org/277134@main>

Reviewed commits have been landed. Closing PR #26877 and removing active labels.

[EWS]

Committed 277212@main (885441cde700): <https://commits.webkit.org/277212@main>

Reviewed commits have been landed. Closing PR #26986 and removing active labels.

[Mark Lam]

We're going to revert this because it's causing crashes.

[Mark Lam]

This was reverted by Justin Michaud in https://commits.webkit.org/277212@main.