transforms

Type Members

1. sealed trait BlackBoxHelperAnno extends Annotation

   

2. case class BlackBoxInlineAnno(target: ModuleName, name: String, text: String) extends BlackBoxHelperAnno with SingleTargetAnnotation[ModuleName] with Product with Serializable

   

3. class BlackBoxNotFoundException extends FirrtlUserException

   

   Exception indicating that a blackbox wasn't found

4. case class BlackBoxPathAnno(target: ModuleName, path: String) extends BlackBoxHelperAnno with SingleTargetAnnotation[ModuleName] with Product with Serializable

   

5. case class BlackBoxResourceAnno(target: ModuleName, resourceId: String) extends BlackBoxHelperAnno with SingleTargetAnnotation[ModuleName] with Product with Serializable

   

6. case class BlackBoxResourceFileNameAnno(resourceFileName: String) extends BlackBoxHelperAnno with NoTargetAnnotation with Product with Serializable

   

7. class BlackBoxSourceHelper extends Transform with DependencyAPIMigration

   

   Handle source for Verilog ExtModules (BlackBoxes)

   Handle source for Verilog ExtModules (BlackBoxes)

   This transform handles the moving of Verilog source for black boxes into the target directory so that it can be accessed by verilator or other backend compilers While parsing it's annotations it looks for a BlackBoxTargetDir annotation that will set the directory where the Verilog will be written. This annotation is typically be set by the execution harness, or directly in the tests

8. case class BlackBoxTargetDirAnno(targetDir: String) extends BlackBoxHelperAnno with NoTargetAnnotation with Product with Serializable

   

9. class CheckCombLoops extends Transform with RegisteredTransform with DependencyAPIMigration

   

   Finds and detects combinational logic loops in a circuit, if any exist.

   Finds and detects combinational logic loops in a circuit, if any exist. Returns the input circuit with no modifications.

   Exceptions thrown

   firrtl.transforms.CheckCombLoops.CombLoopException if a loop is found

   Note

   The pass will throw exceptions on "false paths"

   ,

   The pass relies on ExtModulePathAnnotations to find loops through ExtModules

   ,

   The pass looks for loops through combinational-read memories

   ,

   Output form: Low FIRRTL (identity transform)

   ,

   Input form: Low FIRRTL

10. case class CombinationalPath(sink: ReferenceTarget, sources: Seq[ReferenceTarget]) extends Annotation with Product with Serializable

    

11. class CombineCats extends Transform with DependencyAPIMigration

    

    Combine Cat DoPrims

    Combine Cat DoPrims

    Expands the arguments of any Cat DoPrims if they are references to other Cat DoPrims. Operates only on Cat DoPrims that are node values.

    Use MaxCatLenAnnotation to limit the number of elements that can be concatenated. The default maximum number of elements is 10.

12. class ConstantPropagation extends Transform with DependencyAPIMigration

    

13. class DeadCodeElimination extends Transform with RegisteredTransform with DependencyAPIMigration

    

    Dead Code Elimination (DCE)

    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.

14. class DedupModules extends Transform with DependencyAPIMigration

    

    Only use on legal Firrtl.

    Only use on legal Firrtl.

    Specifically, the restriction of instance loops must have been checked, or else this pass can infinitely recurse.

    Deduped modules are renamed using a chain of 3 RenameMaps. The first RenameMap renames the original annotations.ModuleTargets and relative annotations.InstanceTargets to the groups of absolute annotations.InstanceTargets that they target. These renames only affect instance names and paths and use the old module names. During this rename, modules will also have their instance names renamed if they dedup with a module that has different instance names. The second RenameMap renames all component names within modules that dedup with another module that has different component names. The third RenameMap renames original annotations.ModuleTargets to their deduped annotations.ModuleTarget.

    This transform will also emit DedupedResult for deduped modules that only have one instance.

15. case class DedupedResult(original: ModuleTarget, duplicate: Option[IsModule], index: Double) extends MultiTargetAnnotation with Product with Serializable

    

    Holds the mapping from original module to the instances the original module pointed to The original module target is unaffected by renaming

    Holds the mapping from original module to the instances the original module pointed to The original module target is unaffected by renaming

    original

    Original module

    duplicate

    Instance target of what the original module now points to

    index

    the normalized position of the original module in the original module list, fraction between 0 and 1

16. trait DontTouchAllTargets extends HasDontTouches

    

    A globalized form of HasDontTouches which applies to all ReferenceTargets provided with the annotation

17. case class DontTouchAnnotation(target: ReferenceTarget) extends SingleTargetAnnotation[ReferenceTarget] with DontTouchAllTargets with Product with Serializable

    

    A component that should be preserved

    A component that should be preserved

    DCE treats the component as a top-level sink of the circuit

18. case class ExtModulePathAnnotation(source: ReferenceTarget, sink: ReferenceTarget) extends Annotation with Product with Serializable

    

19. class FixAddingNegativeLiterals extends Transform with DependencyAPIMigration

    

    Replaces adding a negative literal with subtracting that literal

    Replaces adding a negative literal with subtracting that literal

    Verilator has a lint warning if a literal is negated in an expression, because it adds a bit to the literal and thus not all expressions in the add are the same. This is fixed here when we directly subtract the literal instead.

20. class Flatten extends Transform with DependencyAPIMigration

    

    Takes flatten annotations for module instances and modules and inline the entire hierarchy of modules down from the annotations.

    Takes flatten annotations for module instances and modules and inline the entire hierarchy of modules down from the annotations. This transformation instantiates and is based on the InlineInstances transformation.

    Note

    Instances of extmodules are not (and cannot be) inlined

    ,

    Flattening a module means inlining all its fully-defined child instances

21. case class FlattenAnnotation(target: Named) extends SingleTargetAnnotation[Named] with Product with Serializable

    

    Tags an annotation to be consumed by this transform

22. class FlattenRegUpdate extends Transform with DependencyAPIMigration

    

    Flatten register update

    Flatten register update

    This transform flattens register updates into a single expression on the rhs of connection to the register

23. class GroupAndDedup extends GroupComponents

    

    Splits a module into multiple modules by grouping its components via GroupAnnotation's Tries to deduplicate the resulting circuit

24. case class GroupAnnotation(components: Seq[ComponentName], newModule: String, newInstance: String, outputSuffix: Option[String] = None, inputSuffix: Option[String] = None) extends Annotation with Product with Serializable

    

    Specifies a group of components, within a module, to pull out into their own module Components that are only connected to a group's components will also be included

    Specifies a group of components, within a module, to pull out into their own module Components that are only connected to a group's components will also be included

    components

    components in this group

    newModule

    suggested name of the new module

    newInstance

    suggested name of the instance of the new module

    outputSuffix

    suggested suffix of any output ports of the new module

    inputSuffix

    suggested suffix of any input ports of the new module

25. class GroupComponents extends Transform with DependencyAPIMigration

    

    Splits a module into multiple modules by grouping its components via GroupAnnotation's

26. trait HasDontTouches extends AnyRef

    

    Lets an annotation mark its ReferenceTarget members as DontTouch

    Lets an annotation mark its ReferenceTarget members as DontTouch

    This permits a transform to run and remove its associated annotations, thus making their ReferenceTargets new candidates for optimization. This removes the need for the pass writer to reason about pre-existing DontTouchAnnotations that may touch the same node.

27. class InferResets extends Transform with DependencyAPIMigration

    

    Infers the concrete type of ResetTypes by their connections

    Infers the concrete type of ResetTypes by their connections

    There are 3 cases 1. An abstract reset driven by and/or driving only asynchronous resets will be inferred as asynchronous reset 1. An abstract reset driven by and/or driving both asynchronous and synchronous resets will error 1. Otherwise, the reset is inferred as synchronous (i.e. the abstract reset is only invalidated or is driven by or drives only synchronous resets)

    Note

    This transform should be run before DedupModules so that similar Modules from generator languages like Chisel can infer differently

    ,

    This is a global inference because ports can be of type ResetType

28. class InlineBitExtractionsTransform extends Transform with DependencyAPIMigration

    

    Inline nodes that are simple bits

29. class InlineBooleanExpressions extends Transform with DependencyAPIMigration

    

    Inline Bool expressions

    Inline Bool expressions

    The following conditions must be satisfied to inline 1. has type Utils.BoolType 2. is bound to a DefNode with name starting with '_' 3. is bound to a DefNode with a source locator that points at the same file and line number. If it is a MultiInfo source locator, the set of file and line number pairs must be the same. Source locators may point to different column numbers. 4. InlineBooleanExpressionsMax has not been exceeded 5. is not a Mux

30. case class InlineBooleanExpressionsMax(max: Int) extends NoTargetAnnotation with Product with Serializable

    

31. class InlineCastsTransform extends Transform with DependencyAPIMigration

    

    Inline nodes that are simple casts

32. class LegalizeAndReductionsTransform extends Transform with DependencyAPIMigration

    

    Turns andr for expression > 64-bit into equality check with all ones

    Turns andr for expression > 64-bit into equality check with all ones

    Workaround a bug in Verilator v4.026 - v4.032 (inclusive). For context, see https://github.com/verilator/verilator/issues/2300

33. class LegalizeClocksAndAsyncResetsTransform extends Transform with DependencyAPIMigration

    

    Ensure Clocks and AsyncResets to be emitted are legal Verilog

34. case class LogicNode(name: String, inst: Option[String] = None, memport: Option[String] = None) extends Product with Serializable

    

    A case class that represents a net in the circuit.

    A case class that represents a net in the circuit. This is necessary since combinational loop checking is an analysis on the netlist of the circuit; the fields are specialized for low FIRRTL. Since all wires are ground types, a given ground type net may only be a subfield of an instance or a memory port. Therefore, it is uniquely specified within its module context by its name, its optional parent instance (a WDefInstance or WDefMemory), and its optional memory port name.

35. abstract class ManipulateNames[A <: ManipulateNames[_]] extends Transform with DependencyAPIMigration

    

    Transform for manipulate all the names in a FIRRTL circuit.

    Transform for manipulate all the names in a FIRRTL circuit.

    A

    the type of the child transform

36. case class ManipulateNamesAllowlistAnnotation[A <: ManipulateNames[_]](targets: Seq[Seq[Target]], transform: Dependency[A]) extends ManipulateNamesListAnnotation[A] with Product with Serializable

    

    Annotation to filter name manipulation to only manipulate specific Targets in a transform that subclasses ManipulateNames.

    Annotation to filter name manipulation to only manipulate specific Targets in a transform that subclasses ManipulateNames. Targets will be renamed if they are not listed in a ManipulateNamesBlocklistAnnotation and also listed in this annotation.

    Not providing a ManipulateNamesAllowlistAnnotation means that all targets in a circuit may be renamed.

    A

    a sub-type of ManipulateNames

    targets

    FIRRTL IR targets to include in name manipulation

    transform

    the transform that this should apply to

    Exceptions thrown

    java.lang.IllegalArgumentException if any non-local targets are given

    Note

    All targets must be local. Name modification in a non-local target (e.g., a node in a specific instance) makes no structural modification and will be ignored during deduplication. If you want this behavior, use a combination of a sub-class of this annotation and a NoDedupAnnotation.

37. case class ManipulateNamesAllowlistResultAnnotation[A <: ManipulateNames[_]](targets: Seq[Seq[Target]], transform: Dependency[A], oldTargets: Seq[Seq[Target]]) extends MultiTargetAnnotation with Product with Serializable

    

    Records the result of name changes for any targets included in a ManipulateNamesAllowlistAnnotation

    Records the result of name changes for any targets included in a ManipulateNamesAllowlistAnnotation

    If targets are later removed, then a target and old target will be removed from this annotation. If all targets are removed, then this annotation will be deleted.

    targets

    the new targets

    transform

    the transform that performed this rename

    oldTargets

    the old targets

38. case class ManipulateNamesBlocklistAnnotation[A <: ManipulateNames[_]](targets: Seq[Seq[Target]], transform: Dependency[A]) extends ManipulateNamesListAnnotation[A] with Product with Serializable

    

    Annotation to prevent name manipulation ofTargets in a transform that subclasses ManipulateNames.

    Annotation to prevent name manipulation ofTargets in a transform that subclasses ManipulateNames. All listed targets will not be modified.

    A

    a sub-type of ManipulateNames

    targets

    FIRRTL IR targets to exclude from name manipulation

    transform

    the transform that this should apply to

    Exceptions thrown

    java.lang.IllegalArgumentException if any non-local targets are given

    Note

    All targets must be local. Name modification in a non-local target (e.g., a node in a specific instance) makes no structural modification and will be ignored during deduplication. If you want this behavior, use a combination of a sub-class of this annotation and a NoDedupAnnotation.

39. sealed trait ManipulateNamesListAnnotation[A <: ManipulateNames[_]] extends MultiTargetAnnotation

    

    Base trait for annotations that control the behavior of transforms that sub-class ManipulateNames

    Base trait for annotations that control the behavior of transforms that sub-class ManipulateNames

    See also

    ManipulateNamesAllowlistAnnotation

    ManipulateNamesBlocklistAnnotation

40. case class MaxCatLenAnnotation(maxCatLen: Int) extends NoTargetAnnotation with Product with Serializable

    

41. case class NoDedupAnnotation(target: ModuleTarget) extends SingleTargetAnnotation[ModuleTarget] with Product with Serializable

    

    A component, e.g.

    A component, e.g. register etc. Must be declared only once under the TopAnnotation

42. case class OptimizableExtModuleAnnotation(target: ModuleName) extends SingleTargetAnnotation[ModuleName] with Product with Serializable

    

    An firrtl.ir.ExtModule that can be optimized

    An firrtl.ir.ExtModule that can be optimized

    Firrtl does not know the semantics of an external module. This annotation provides some "greybox" information that the external module does not have any side effects. In particular, this means that the external module can be Dead Code Eliminated.

    Note

    Unlike DontTouchAnnotation, we don't care if the annotation is deleted

43. class PropagatePresetAnnotations extends Transform with DependencyAPIMigration

    

    Propagate PresetAnnotations to all children of targeted AsyncResets Leaf Registers are annotated with PresetRegAnnotation All wires, nodes and connectors along the way are suppressed

    Propagate PresetAnnotations to all children of targeted AsyncResets Leaf Registers are annotated with PresetRegAnnotation All wires, nodes and connectors along the way are suppressed

    Processing of multiples targets are NOT isolated from one another as the expected outcome does not differ Annotations of leaf registers, wires, nodes & connectors does indeed not depend on the initial AsyncReset reference The set of created annotation based on multiple initial AsyncReset PresetAnnotation

    This transform consists of 2 successive walk of the AST I./ Propagate

    • 1./ Create all AsyncResetTrees
    • 2./ Leverage them to annotate register for specialized emission & PresetTree for cleanUp II./ CleanUpTree
    • clean up all the intermediate nodes (replaced with EmptyStmt)
    • raise Error on orphans (typically cast of Annotated Reset)
    • disconnect Registers from their reset nodes (replaced with UInt(0))

    Thanks to the clean-up phase, this transform does not rely on DCE

    Note

    This pass must run before InlineCastsTransform

44. class RemoveKeywordCollisions extends ManipulateNames[Nothing]

    

    Transform that removes collisions with reserved keywords

45. class RemoveWires extends Transform with DependencyAPIMigration

    

    Replace wires with nodes in a legal, flow-forward order

    Replace wires with nodes in a legal, flow-forward order

    This pass must run after LowerTypes because Aggregate-type wires have multiple connections that may be impossible to order in a flow-foward way

46. class RenameModules extends Transform with DependencyAPIMigration

    

    Rename Modules

    Rename Modules

    using namespace created by analyses.GetNamespace, create unique names for modules

47. class ReplaceTruncatingArithmetic extends Transform with DependencyAPIMigration

    

    Replaces non-expanding arithmetic

    Replaces non-expanding arithmetic

    In the case where the result of add or sub immediately throws away the expanded msb, this transform will replace the operation with a non-expanding operator addw or subw respectively.

    Note

    This replaces some FIRRTL primops with ops that are not actually legal FIRRTL. They are useful for emission to languages that support non-expanding arithmetic (like Verilog)

48. class SimplifyMems extends Transform with DependencyAPIMigration

    

    Lowers memories without splitting them, but without the complexity of ReplaceMemMacros

49. class VerilogRename extends RemoveKeywordCollisions

    

    Transform that removes collisions with Verilog keywords

50. class IdentityTransform extends Transform

    

    Transform that applies an identity function.

    Transform that applies an identity function. This returns an unmodified CircuitState.

    Annotations

    @deprecated

    Deprecated

    (Since version FIRRTL 1.3) mix-in firrtl.options.IdentityLike[CircuitState]. IdentityTransform will be removed in 1.4.

51. type LegalizeClocksTransform = LegalizeClocksAndAsyncResetsTransform

    

    Annotations

    @deprecated

    Deprecated

    (Since version FIRRTL 1.4.0) Replaced by LegalizeClocksAndAsyncResetsTransform