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All transforms that must run after this transform
All transforms that must run after this transform
This is a means of prerequisite injection into some other transform. Normally a transform will define its own prerequisites. Dependents exist for two main situations:
First, they improve the composition of optional transforms. If some first transform is optional (e.g., an expensive validation check), you would like to be able to conditionally cause it to run. If it is listed as a prerequisite on some other, second transform then it must always run before that second transform. There's no way to turn it off. However, by listing the second transform as a dependent of the first transform, the first transform will only run (and be treated as a prerequisite of the second transform) if included in a list of target transforms that should be run.
Second, an external library would like to inject some first transform before a second transform inside FIRRTL. In this situation, the second transform cannot have any knowledge of external libraries. The use of a dependent here allows for prerequisite injection into FIRRTL proper.
The use of a Seq here is to preserve input order. Internally, this will be converted to a private, ordered Set.
firrtl.passes.CheckTypes for an example of an optional checking firrtl.Transform
A function that, given *another* transform (parameter a) will return true if this transform invalidates/undos the
effects of the *other* transform (parameter a).
A function that, given *another* transform (parameter a) will return true if this transform invalidates/undos the
effects of the *other* transform (parameter a).
transform
All transform that must run before this transform
All transform that must run before this transform
The use of a Seq here is to preserve input order. Internally, this will be converted to a private, ordered Set.
Mixin that defines dependencies between TransformLikes (hereafter referred to as "transforms")
This trait forms the basis of the Dependency API of the Chisel/FIRRTL Hardware Compiler Framework. Dependencies are defined in terms of prerequisistes, dependents, and invalidates. A prerequisite is a transform that must run before this transform. A dependent is a transform that must run after this transform. (This can be viewed as a means of injecting a prerequisite into some other transform.) Finally, invalidates define the set of transforms whose effects this transform undos/invalidates. (Invalidation then implies that a transform that is invalidated by this transform and needed by another transform will need to be re-run.)
This Dependency API only defines dependencies. A concrete DependencyManager is expected to be used to statically resolve a linear ordering of transforms that satisfies dependency requirements.
some transform