scala.tools.nsc.transform

# SpecializeTypes

###
Related Doc: package transform

#### abstract class SpecializeTypes extends SubComponent with InfoTransform with TypingTransformers

Specialize code on types.

Make sure you've read the thesis:

Iulian Dragos: Compiling Scala for Performance (chapter 4)

There are some things worth noting, (possibly) not mentioned there: 0) Make sure you understand the meaning of various `SpecializedInfo` descriptors defined below.

1) Specializing traits by introducing bridges in specialized methods of the specialized trait may introduce problems during mixin composition. Concretely, it may cause cyclic calls and result in a stack overflow. See ticket #4351. This was solved by introducing an `Abstract` specialized info descriptor. Instead of generating a bridge in the trait, an abstract method is generated.

2) Specialized private members sometimes have to be switched to protected. In some cases, even this is not enough. Example:

    class A[@specialized T](protected val d: T) {
      def foo(that: A[T]) = that.d
    }

Specialization will generate a specialized class and a specialized method:

    class A$mcI$sp(protected val d: Int) extends A[Int] {
      def foo(that: A[Int]) = foo$mcI$sp(that)
      def foo(that: A[Int]) = that.d
    }

Above, `A$mcI$sp` cannot access `d`, so the method cannot be typechecked.

Source
  SpecializeTypes.scala

Linear Supertypes
TypingTransformers, InfoTransform, Transform, SubComponent, AnyRef, Any
Known Subclasses
specializeTypes
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Inherited

1. SpecializeTypes
2. TypingTransformers
3. InfoTransform
4. Transform
5. SubComponent
6. AnyRef
7. Any

Implicitly

1. by any2stringadd
2. by StringFormat
3. by Ensuring
4. by ArrowAssoc

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### Instance Constructors

1. #### new SpecializeTypes()

### Type Members

1. #### case class Abstract(t: Global.Symbol) extends SpecializedInfo with Product with Serializable

   Symbol is a specialized abstract method, either specialized or original.

   Symbol is a specialized abstract method, either specialized or original. The original `t` is abstract.

2. #### class Duplicator extends Duplicators

   This duplicator additionally performs casts of expressions if that is allowed by the `casts` map.

3. #### case class Forward(t: Global.Symbol) extends SpecializedInfo with Product with Serializable

   Symbol is a method that should be forwarded to 't'

4. #### case class Implementation(target: Global.Symbol) extends SpecializedInfo with Product with Serializable

   Symbol is a specialized method whose body should be the target's method body.

5. #### class ImplementationAdapter extends Global.TreeSymSubstituter

   A tree symbol substituter that substitutes on type skolems.

   A tree symbol substituter that substitutes on type skolems. If a type parameter is a skolem, it looks for the original symbol in the 'from' and maps it to the corresponding new symbol. The new symbol should probably be a type skolem as well (not enforced).

   All private members are made protected in order to be accessible from specialized classes.

6. #### case class NormalizedMember(target: Global.Symbol) extends SpecializedInfo with Product with Serializable

   Symbol is a normalized member obtained by specializing 'target'.

7. #### case class Overload(sym: Global.Symbol, env: TypeEnv) extends Product with Serializable

8. #### class Phase extends InfoTransform.Phase

   Definition Classes
     InfoTransform

9. #### case class SpecialOverload(original: Global.Symbol, env: TypeEnv) extends SpecializedInfo with Product with Serializable

   Symbol is a special overloaded method of 'original', in the environment env.

10. #### case class SpecialOverride(target: Global.Symbol) extends SpecializedInfo with Product with Serializable

    Symbol is a specialized override paired with `target`.

11. #### case class SpecialSuperAccessor(t: Global.Symbol) extends SpecializedInfo with Product with Serializable

    Symbol is a special overload of the super accessor.

12. #### class SpecializationDuplicator extends Duplicator

    Introduced to fix SI-7343: Phase ordering problem between Duplicators and Specialization.

    Introduced to fix SI-7343: Phase ordering problem between Duplicators and Specialization. brief explanation: specialization rewires class parents during info transformation, and the new info then guides the tree changes. But if a symbol is created during duplication, which runs after specialization, its info is not visited and thus the corresponding tree is not specialized. One manifestation is the following: ```object Test { class Parent[@specialized(Int) T]```

    def spec_method[@specialized(Int) T](t: T, expectedXSuper: String) = { class X extends Parent[T]() // even in the specialized variant, the local X class // doesn't extend Parent$mcI$sp, since its symbol has // been created after specialization and was not seen // by specialization's info transformer. ... } } ```We fix this by forcing duplication to take place before specialization.```

    Note: The constructors phase (which also uses duplication) comes after erasure and uses the post-erasure typer => we must protect it from the beforeSpecialization phase shifting.

13. #### class SpecializationPhase extends Phase

14. #### class SpecializationTransformer extends Global.Transformer

15. #### case class SpecializedAccessor(target: Global.Symbol) extends SpecializedInfo with Product with Serializable

    Symbol is a specialized accessor for the `target` field.

16. #### abstract class SpecializedInfo extends AnyRef

17. #### case class SpecializedInnerClass(target: Global.Symbol, env: TypeEnv) extends SpecializedInfo with Product with Serializable

    A specialized inner class that specializes original inner class `target` on a type parameter of the enclosing class, in the typeenv `env`.

18. #### abstract class StdPhase extends GlobalPhase

    A standard phase template

    A standard phase template

    Definition Classes
      SubComponent

19. #### type TypeEnv = Map[Global.Symbol, Global.Type]

20. #### abstract class TypingTransformer extends Global.Transformer

    Definition Classes
      TypingTransformers

### Abstract Value Members

1. #### abstract val global: Global

   Definition Classes
     TypingTransformers

2. #### abstract val runsAfter: List[String]

   Names of phases that must run before this phase.

   Names of phases that must run before this phase.

   Definition Classes
     SubComponent

3. #### abstract val runsRightAfter: Option[String]

   Name of the phase that this phase must follow immediately.

   Name of the phase that this phase must follow immediately.

   Definition Classes
     SubComponent

### Concrete Value Members

1. #### final def !=(arg0: Any): Boolean

   Test two objects for inequality.

   Test two objects for inequality.

   returns

     `true` if !(this == that), false otherwise.

   Definition Classes
     AnyRef → Any

2. #### final def ##(): Int

   Equivalent to `x.hashCode` except for boxed numeric types and `null`.

   Equivalent to `x.hashCode` except for boxed numeric types and `null`. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For `null` returns a hashcode where `null.hashCode` throws a `NullPointerException`.

   returns

     a hash value consistent with ==

   Definition Classes
     AnyRef → Any

3. #### def +(other: String): String

   Implicit information
     This member is added by an implicit conversion from SpecializeTypes to any2stringadd[SpecializeTypes] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd

4. #### def ->[B](y: B): (SpecializeTypes, B)

   Implicit information
     This member is added by an implicit conversion from SpecializeTypes to ArrowAssoc[SpecializeTypes] performed by method ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @inline()

5. #### final def ==(arg0: Any): Boolean

   The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

   The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

   arg0

     the object to compare against this object for equality.

   returns

     `true` if the receiver object is equivalent to the argument; `false` otherwise.

   Definition Classes
     AnyRef → Any

6. #### object TypeEnv

7. #### object UnifyError extends Throwable with ControlThrowable with Product with Serializable

8. #### def addConcreteSpecMethod(m: Global.Symbol): Unit

   Add method m to the set of symbols for which we need an implementation tree in the tree transformer.

   Add method m to the set of symbols for which we need an implementation tree in the tree transformer.

   Note

     This field is part of the specializeTypes subcomponent, so any symbols that here are not garbage collected at the end of a compiler run!

9. #### final def afterOwnPhase[T](op: ⇒ T): T

   Definition Classes
     SubComponent
   Annotations
     @inline()

10. #### final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type `T0`.

    Cast the receiver object to be of type `T0`.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression `1.asInstanceOf[String]` will throw a `ClassCastException` at runtime, while the expression `List(1).asInstanceOf[List[String]]` will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

    returns

      the receiver object.

    Definition Classes
      Any
    Exceptions thrown

      `ClassCastException` if the receiver object is not an instance of the erasure of type `T0`.

11. #### final def beforeOwnPhase[T](op: ⇒ T): T

    Definition Classes
      SubComponent
    Annotations
      @inline()

12. #### def changesBaseClasses: Boolean

    This phase changes base classes.

    This phase changes base classes.

    Definition Classes
      SpecializeTypes → InfoTransform

13. #### def clone(): AnyRef

    Create a copy of the receiver object.

    Create a copy of the receiver object.

    The default implementation of the `clone` method is platform dependent.

    returns

      a copy of the receiver object.

    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
    Note

      not specified by SLS as a member of AnyRef

14. #### def concreteTypes(sym: Global.Symbol): List[Global.Type]

    Return the types `sym` should be specialized at.

    Return the types `sym` should be specialized at. This may be some of the primitive types or AnyRef. AnyRef means that a new type parameter T will be generated later, known to be a subtype of AnyRef (T <: AnyRef). These are in a meaningful order for stability purposes.

15. #### def emptyEnv: TypeEnv

16. #### def enabled: Boolean

    Is this component enabled? Default is true.

    Is this component enabled? Default is true.

    Definition Classes
      SubComponent

17. #### def ensuring(cond: (SpecializeTypes) ⇒ Boolean, msg: ⇒ Any): SpecializeTypes

    Implicit information
      This member is added by an implicit conversion from SpecializeTypes to Ensuring[SpecializeTypes] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

18. #### def ensuring(cond: (SpecializeTypes) ⇒ Boolean): SpecializeTypes

    Implicit information
      This member is added by an implicit conversion from SpecializeTypes to Ensuring[SpecializeTypes] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

19. #### def ensuring(cond: Boolean, msg: ⇒ Any): SpecializeTypes

    Implicit information
      This member is added by an implicit conversion from SpecializeTypes to Ensuring[SpecializeTypes] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

20. #### def ensuring(cond: Boolean): SpecializeTypes

    Implicit information
      This member is added by an implicit conversion from SpecializeTypes to Ensuring[SpecializeTypes] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

21. #### final def eq(arg0: AnyRef): Boolean

    Tests whether the argument (`arg0`) is a reference to the receiver object (`this`).

    Tests whether the argument (`arg0`) is a reference to the receiver object (`this`).

    The `eq` method implements an equivalence relation on non-null instances of `AnyRef`, and has three additional properties:

    - It is consistent: for any non-null instances `x` and `y` of type `AnyRef`, multiple invocations of `x.eq(y)` consistently returns `true` or consistently returns `false`.
    - For any non-null instance `x` of type `AnyRef`, `x.eq(null)` and `null.eq(x)` returns `false`.
    - `null.eq(null)` returns `true`.

    When overriding the `equals` or `hashCode` methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (`o1 eq o2`), they should be equal to each other (`o1 == o2`) and they should hash to the same value (`o1.hashCode == o2.hashCode`).

    returns

      `true` if the argument is a reference to the receiver object; `false` otherwise.

    Definition Classes
      AnyRef

22. #### def equals(arg0: Any): Boolean

    The equality method for reference types.

    The equality method for reference types. Default implementation delegates to `eq`.

    See also `equals` in scala.Any.

    returns

      `true` if the receiver object is equivalent to the argument; `false` otherwise.

    Definition Classes
      AnyRef → Any

23. #### def finalize(): Unit

    Called by the garbage collector on the receiver object when there are no more references to the object.

    Called by the garbage collector on the receiver object when there are no more references to the object.

    The details of when and if the `finalize` method is invoked, as well as the interaction between `finalize` and non-local returns and exceptions, are all platform dependent.

    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )
    Note

      not specified by SLS as a member of AnyRef

24. #### def formatted(fmtstr: String): String

    Implicit information
      This member is added by an implicit conversion from SpecializeTypes to StringFormat[SpecializeTypes] performed by method StringFormat in scala.Predef.
    Definition Classes
      StringFormat
    Annotations
      @inline()

25. #### final def getClass(): Class[_]

    A representation that corresponds to the dynamic class of the receiver object.

    A representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

      a representation that corresponds to the dynamic class of the receiver object.

    Definition Classes
      AnyRef → Any
    Note

      not specified by SLS as a member of AnyRef

26. #### def hasSpecializedParams(clazz: Global.Symbol): Boolean

    Has `clazz` any type parameters that need be specialized?

27. #### def hashCode(): Int

    SubComponent are added to a HashSet and two phases are the same if they have the same name

    SubComponent are added to a HashSet and two phases are the same if they have the same name

    returns

      the hash code value for this object.

    Definition Classes
      SubComponent → AnyRef → Any

28. #### def illegalSpecializedInheritance(clazz: Global.Symbol): Boolean

29. #### val initial: Boolean

    True if this phase runs before all other phases.

    True if this phase runs before all other phases. Usually, `parser`.

    Definition Classes
      SubComponent

30. #### val internal: Boolean

    True if this phase is not provided by a plug-in.

    True if this phase is not provided by a plug-in.

    Definition Classes
      SubComponent

31. #### final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object is `T0`.

    Test whether the dynamic type of the receiver object is `T0`.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression `1.isInstanceOf[String]` will return `false`, while the expression `List(1).isInstanceOf[List[String]]` will return `true`. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

    returns

      `true` if the receiver object is an instance of erasure of type `T0`; `false` otherwise.

    Definition Classes
      Any

32. #### def isNormalizedMember(m: Global.Symbol): Boolean

33. #### def keepsTypeParams: Boolean

    Definition Classes
      SpecializeTypes → InfoTransform

34. #### final def ne(arg0: AnyRef): Boolean

    Equivalent to `!(this eq that)`.

    Equivalent to `!(this eq that)`.

    returns

      `true` if the argument is not a reference to the receiver object; `false` otherwise.

    Definition Classes
      AnyRef

35. #### def newPhase(prev: nsc.Phase): StdPhase

    Just to mark uncheckable

    Just to mark uncheckable

    Definition Classes
      SpecializeTypes → InfoTransform → Transform → SubComponent

36. #### def newTransformer(unit: Global.CompilationUnit): Global.Transformer

    The transformer factory

    The transformer factory

    Attributes
      protected
    Definition Classes
      SpecializeTypes → Transform

37. #### def nonConflicting(env: TypeEnv): Boolean

    Is any type variable in `env` conflicting with any if its type bounds, when type bindings in `env` are taken into account?

    Is any type variable in `env` conflicting with any if its type bounds, when type bindings in `env` are taken into account?

    A conflicting type environment could still be satisfiable.

38. #### final def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Note

      not specified by SLS as a member of AnyRef

39. #### final def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Note

      not specified by SLS as a member of AnyRef

40. #### def originalClass(clazz: Global.Symbol): Global.Symbol

    Return the generic class corresponding to this specialized class.

41. #### def ownPhase: nsc.Phase

    The phase corresponding to this subcomponent in the current compiler run

    The phase corresponding to this subcomponent in the current compiler run

    Definition Classes
      SubComponent

42. #### val phaseName: String

    the name of the phase:

    the name of the phase:

    Definition Classes
      SpecializeTypes → SubComponent

43. #### def phaseNewFlags: Long

    The following flags may be set by this phase:

    The following flags may be set by this phase:

    Definition Classes
      SpecializeTypes → SubComponent

44. #### def phaseNextFlags: Long

    New flags defined by the phase which are not valid until immediately after it

    New flags defined by the phase which are not valid until immediately after it

    Definition Classes
      SubComponent

45. #### def produceTypeParameters(syms: List[Global.Symbol], nowner: Global.Symbol, env: TypeEnv): collection.immutable.List[Global.Symbol]

    Produces the symbols from type parameters `syms` of the original owner, in the given type environment `env`.

    Produces the symbols from type parameters `syms` of the original owner, in the given type environment `env`. The new owner is `nowner`.

    Non-specialized type parameters are cloned into new ones. Type parameters specialized on AnyRef have preexisting symbols.

    For instance, a @specialized(AnyRef) T, will become T$sp <: AnyRef.

46. #### val requires: List[String]

    Names of phases required by this component.

    Names of phases required by this component. Default is `Nil`.

    Definition Classes
      SubComponent

47. #### val runsBefore: List[String]

    Names of phases that must run after this phase.

    Names of phases that must run after this phase. Default is `Nil`.

    Definition Classes
      SubComponent

48. #### def satisfiabilityConstraints(env: TypeEnv): Option[TypeEnv]

49. #### def satisfiable(env: TypeEnv, warnings: Boolean): Boolean

50. #### def satisfiable(env: TypeEnv): Boolean

    The type environment is sound w.r.t.

    The type environment is sound w.r.t. to all type bounds or only soft conflicts appear. An environment is sound if all bindings are within the bounds of the given type variable. A soft conflict is a binding that does not fall within the bounds, but whose bounds contain type variables that are @specialized, (that could become satisfiable).

51. #### lazy val specializableTypes: collection.immutable.List[Global.Type]

52. #### def specializeCalls(unit: Global.CompilationUnit): TypingTransformer { ... /* 7 definitions in type refinement */ }

53. #### def specializeClass(clazz: Global.Symbol, outerEnv: TypeEnv): List[Global.Symbol]

    Specialize 'clazz', in the environment `outerEnv`.

    Specialize 'clazz', in the environment `outerEnv`. The outer environment contains bindings for specialized types of enclosing classes.

    A class C is specialized w.r.t to its own specialized type params `stps`, by specializing its members, and creating a new class for each combination of `stps`.

54. #### val specializedClass: HashMap[(Global.Symbol, TypeEnv), Global.Symbol]

    For a given class and concrete type arguments, give its specialized class

55. #### def specializedParams(sym: Global.Symbol): List[Global.Symbol]

    Return specialized type parameters.

56. #### val specializedType: Global.TypeMap

57. #### def specializedTypeVars(tpe: Global.Type): Set[Global.Symbol]

    Return the set of @specialized type variables mentioned by the given type.

    Return the set of @specialized type variables mentioned by the given type. It only counts type variables that appear:

    - naked
    - as arguments to type constructors in @specialized positions (arrays are considered as Array[@specialized T])

58. #### def specializedTypeVars(sym: Global.Symbol): Set[Global.Symbol]

59. #### def specializedTypeVars(tpes: List[Global.Type]): Set[Global.Symbol]

60. #### def specializesClass(sym: Global.Symbol): Global.Symbol

    If the symbol is the companion of a value class, the value class.

    If the symbol is the companion of a value class, the value class. Otherwise, AnyRef.

61. #### def survivingArgs(sym: Global.Symbol, args: List[Global.Type]): List[Global.Type]

    Given an original class symbol and a list of types its type parameters are instantiated at returns a list of type parameters that should remain in the TypeRef when instantiating a specialized type.

62. #### def survivingParams(params: List[Global.Symbol], env: TypeEnv): collection.immutable.List[Global.Symbol]

    Type parameters that survive when specializing in the specified environment.

63. #### final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
      AnyRef

64. #### val terminal: Boolean

    True if this phase runs after all other phases.

    True if this phase runs after all other phases. Usually, `terminal`.

    Definition Classes
      SubComponent

65. #### def toString(): String

    Creates a String representation of this object.

    Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

    returns

      a String representation of the object.

    Definition Classes
      AnyRef → Any

66. #### def transformInfo(sym: Global.Symbol, tpe: Global.Type): Global.Type

    Type transformation.

    Type transformation. It is applied to all symbols, compiled or loaded. If it is a 'no-specialization' run, it is applied only to loaded symbols.

    Definition Classes
      SpecializeTypes → InfoTransform

67. #### final def wait(): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

68. #### final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

69. #### final def wait(arg0: Long): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

70. #### def →[B](y: B): (SpecializeTypes, B)

    Implicit information
      This member is added by an implicit conversion from SpecializeTypes to ArrowAssoc[SpecializeTypes] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc

### Inherited from TypingTransformers

### Inherited from InfoTransform

### Inherited from Transform

### Inherited from SubComponent

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd from SpecializeTypes to any2stringadd[SpecializeTypes]

### Inherited by implicit conversion StringFormat from SpecializeTypes to StringFormat[SpecializeTypes]

### Inherited by implicit conversion Ensuring from SpecializeTypes to Ensuring[SpecializeTypes]

### Inherited by implicit conversion ArrowAssoc from SpecializeTypes to ArrowAssoc[SpecializeTypes]

### Ungrouped