c

firrtl.transforms

DeadCodeElimination

class DeadCodeElimination extends Transform

Dead Code Elimination (DCE)

Performs DCE by constructing a global dependency graph starting with top-level outputs, external module ports, and simulation constructs as circuit sinks. External modules can optionally be eligible for DCE via the OptimizableExtModuleAnnotation.

Dead code is eliminated across module boundaries. Wires, ports, registers, and memories are all eligible for removal. Components marked with a DontTouchAnnotation will be treated as a circuit sink and thus anything that drives such a marked component will NOT be removed.

This transform preserves deduplication. All instances of a given firrtl.ir.DefModule are treated as the same individual module. Thus, while certain instances may have dead code due to the circumstances of their instantiation in their parent module, they will still not be removed. To remove such modules, use the NoDedupAnnotation to prevent deduplication.

Linear Supertypes
Transform, LazyLogging, AnyRef, Any
Type Hierarchy
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. DeadCodeElimination
  2. Transform
  3. LazyLogging
  4. AnyRef
  5. Any
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Visibility
  1. Public
  2. All

Instance Constructors

  1. new DeadCodeElimination()

Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##(): Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  5. def clone(): AnyRef
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @native() @throws( ... )
  6. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  7. def equals(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  8. def execute(state: CircuitState): CircuitState

    Perform the transform, encode renaming with RenameMap, and can delete annotations Called by runTransform.

    Perform the transform, encode renaming with RenameMap, and can delete annotations Called by runTransform.

    state

    Input Firrtl AST

    returns

    A transformed Firrtl AST

    Definition Classes
    DeadCodeElimination → Transform
  9. def extractRefs(expr: Expression): Seq[Expression]

    Extract all References and SubFields from a possibly nested Expression

  10. def finalize(): Unit
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  11. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  12. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  13. def inputForm: LowForm.type

    The firrtl.CircuitForm that this transform requires to operate on

    The firrtl.CircuitForm that this transform requires to operate on

    Definition Classes
    DeadCodeElimination → Transform
  14. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  15. val logger: Logger
    Definition Classes
    LazyLogging
  16. def name: String

    A convenience function useful for debugging and error messages

    A convenience function useful for debugging and error messages

    Definition Classes
    Transform
  17. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  18. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  19. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  20. def outputForm: LowForm.type

    The firrtl.CircuitForm that this transform outputs

    The firrtl.CircuitForm that this transform outputs

    Definition Classes
    DeadCodeElimination → Transform
  21. def run(state: CircuitState, dontTouches: Seq[LogicNode], doTouchExtMods: Set[String]): CircuitState
  22. final def runTransform(state: CircuitState): CircuitState

    Perform the transform and update annotations.

    Perform the transform and update annotations.

    state

    Input Firrtl AST

    returns

    A transformed Firrtl AST

    Definition Classes
    Transform
  23. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  24. def toString(): String
    Definition Classes
    AnyRef → Any
  25. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  26. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  27. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @throws( ... )

Deprecated Value Members

  1. final def getMyAnnotations(state: CircuitState): Seq[Annotation]

    Convenience method to get annotations relevant to this Transform

    Convenience method to get annotations relevant to this Transform

    state

    The CircuitState form which to extract annotations

    returns

    A collection of annotations

    Definition Classes
    Transform
    Annotations
    @deprecated
    Deprecated

    (Since version 1.1) Just collect the actual Annotation types the transform wants

Inherited from Transform

Inherited from LazyLogging

Inherited from AnyRef

Inherited from Any

Ungrouped