Class field layout

The class field layout table shows the layout of a class or struct, including inherited members, and holes.

The table reflects multiple build configurations and the platforms.

If the layout differs between them, for example with the following reasons, a row is created for each group.

  • Debug-only fields

  • Pointer size difference between platforms

Enabling Class field layout: To use class field layout features, visit the settings page and change the “Default feature gate” from “Release” to “Alpha”, or use the “Semantic Info Queries gate” setting.

Class field layout table

Context Menu

The context menu for classes
Class layout of …

Open the class field layout table of given class.

Controls

Use Ascending Order/Use Descending Order

Order the classes in the ascending/descending order of the offset.

By default, descending order is used, and thus the specified class is shown in the top, and the base classes are shown below it.

Choosing the ascending order makes the all fields orderedby the field offset.

Columns

Select the columns to show.

Corresponds to the show-cols:LIST parameter.

Name

The name of the field.

Type

The actual type of the field.

Line

The actual line that declares the field. This can be a macro invocation.

Queries

Show the class field layout table of given a class or struct.

field-layout:'nsTString'

https://searchfox.org/mozilla-central/query/default?q=field-layout%3A%27nsTString%27