Packages

  • package root

    The Scala compiler and reflection APIs.

    The Scala compiler and reflection APIs.

    Definition Classes
    root
  • package scala
    Definition Classes
    root
  • package tools
    Definition Classes
    scala
  • package nsc
    Definition Classes
    tools
  • package transform
    Definition Classes
    nsc
  • abstract class TailCalls extends SubComponent with Transform

    Perform tail recursive call elimination.

    Perform tail recursive call elimination.

    Definition Classes
    transform
    Version

    1.0

  • class TailCallElimination extends Global.Transformer

    A Tail Call Transformer

    A Tail Call Transformer

    Definition Classes
    TailCalls
    Version

    1.1 What it does: Finds method calls in tail-position and replaces them with jumps. A call is in a tail-position if it is the last instruction to be executed in the body of a method. This is done by recursing over the trees that may contain calls in tail-position (trees that can't contain such calls are not transformed). However, they are not that many. Self-recursive calls in tail-position are replaced by jumps to a label at the beginning of the method. As the JVM provides no way to jump from a method to another one, non-recursive calls in tail-position are not optimized. A method call is self-recursive if it calls the current method and the method is final (otherwise, it could be a call to an overridden method in a subclass). Furthermore, If the method has type parameters, the call must contain these parameters as type arguments. Recursive calls on a different instance are optimized. Since 'this' is not a local variable, a dummy local val is added and used as a label parameter. The backend knows to load the corresponding argument in the 'this' (local at index 0). This dummy local is never used and should be cleaned up by dead code elimination (when enabled). This phase has been moved before pattern matching to catch more of the common cases of tail recursive functions. This means that more cases should be taken into account (like nested function, and pattern cases). If a method contains self-recursive calls, a label is added to at the beginning of its body and the calls are replaced by jumps to that label. Assumes: Uncurry has been run already, and no multiple parameter lists exist.

  • ClonedTailContext
  • DefDefTailContext
  • EmptyTailContext
  • TailContext

object EmptyTailContext extends TailContext

Source
TailCalls.scala
Linear Supertypes
TailContext, AnyRef, Any
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. EmptyTailContext
  2. TailContext
  3. AnyRef
  4. Any
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Visibility
  1. Public
  2. All

Value Members

  1. def enclosingType: Global.Type
    Definition Classes
    TailContext
  2. def isEligible: Boolean
    Definition Classes
    TailContext
  3. def isMandatory: Boolean
    Definition Classes
    TailContext
  4. def isTransformed: Boolean
    Definition Classes
    TailContext
  5. def label: Global.NoSymbol
    Definition Classes
    EmptyTailContext → TailContext
  6. def method: Global.NoSymbol
    Definition Classes
    EmptyTailContext → TailContext
  7. def methodPos: NoPosition.type
    Definition Classes
    EmptyTailContext → TailContext
  8. def newThis(pos: Global.Position): Global.TermSymbol
    Definition Classes
    TailContext
  9. final def noTailContext(): TailContext
    Definition Classes
    TailContext
  10. def tailLabels: Set[Global.Symbol]
    Definition Classes
    EmptyTailContext → TailContext
  11. def tailPos: Boolean
    Definition Classes
    EmptyTailContext → TailContext
  12. def toString(): String
    Definition Classes
    TailContext → AnyRef → Any
  13. def tparams: collection.immutable.Nil.type
    Definition Classes
    EmptyTailContext → TailContext
  14. final def yesTailContext(): TailContext
    Definition Classes
    TailContext