1442903 - Web Replay: Record/replay assertion changes

Status: RESOLVED INVALID

(Core :: General, enhancement)

Description

[Brian Hackett [Laid off!]]

Record/replay assertions can be stuck into the source (usually C++, but JS is also supported) to add checks that the replay is lining up with the recording.  Currently there are a fair number of these scattered around the codebase, mostly leftover from previous issues that have since been tracked down.  See Part 9b in bug 1422587.  This bug will keep track of changes to these assertions.  Before landing to m-c they will all (or mostly) be stripped out.

Comment 1

[Brian Hackett [Laid off!]]

Attachment: Part 1 - Remove invalid ThingIndex uses in layout code.

The ThingIndex APIs in RecordReplay.h are used to associate pointer values (which can vary between recording/replay) with unique integer values (which should not vary between recording/replay).  This API is flexible but a bit of a footgun because if a pointer was never registered with the API then getting its index can produce a non-deterministic result: the index of some other pointer previously at that address may be returned instead.  This patch fixes a couple places where ThingIndex was used on pointers that were never registered, causing bogus divergence reports.

Comment 2

[Brian Hackett [Laid off!]]

https://hg.mozilla.org/projects/ash/rev/8530a6b76c736d3ad2a212c91bb12a9dfb326d21

Comment 3

[Brian Hackett [Laid off!]]

Closing this bug, all the changes here will be reviewed in separate bugs dependent on bug 1422587.