abstract class Fields extends SubComponent with InfoTransform with TreeDSL with TypingTransformers with AccessorSynthesis
Synthesize accessors, fields (and bitmaps) for (lazy) vals and modules.
During Namers, a ValDef
that is lazy
, deferred and/or defined in a trait carries its getter's symbol.
The underlying field symbol does not exist until this phase.
For val
s defined in classes, we still emit a field immediately.
TODO: uniformly assign getter symbol to all ValDef
s, stop using accessed
.
This phase synthesizes accessors, fields and bitmaps (for lazy or init-checked vals under -Xcheckinit) in the first (closest in the subclassing lattice) subclass (not a trait) of a trait.
For lazy vals and modules, we emit accessors that using double-checked locking (DCL) to balance thread safety and performance. For both lazy vals and modules, the a compute method contains the DCL's slow path.
Local lazy vals do not receive bitmaps, but use a Lazy*Holder that has the volatile init bit and the computed value.
See mkLazyLocalDef
.
Constructors will move the rhs to an assignment in the template body. Those statements then move to the template into the constructor, which means it will initialize the fields defined in this template (and execute the corresponding side effects). We need to maintain the connection between getter and rhs until after specialization so that it can duplicate vals.
A ModuleDef is desugared to a ClassDef, an accessor (which reuses the module's term symbol) and a module var (unless the module is static and does not implement a member of a supertype, or we're in a trait).
For subclasses of traits that define modules, a module var is mixed in, as well as the required module accessors.
Phase ordering:
- Runs after uncurry to deal with classes that implement SAM traits with ValDefs.
- Runs before erasure (to get bridges), and thus before lambdalift/flatten, so that nested functions/definitions must be considered.
- Lambdalift introduces new paramaccessors for captured vals, but runs too late in the pipeline, so mixins still synthesizes implementations for these accessors when a local trait that captures is subclassed.
In the future, would like to get closer to dotty, which lifts a val's RHS (a similar thing is done for template-level statements)
to a method $_initialize_$1$x
instead of a block, which is used in the constructor to initialize the val.
This makes for a nice unification of strict and lazy vals, in that the RHS is lifted to a method for both,
with the corresponding compute method called at the appropriate time.)
This only reduces the required number of methods per field declaration in traits, if we encode the name (and place in initialisation order) of the field in the name of its initializing method, to allow separate compilation. (The name mangling must include ordering, and thus complicate incremental compilation: ideally, we'd avoid renumbering unchanged methods, but that would result in different bytecode between clean recompiles and incremental ones).
In the even longer term (Scala 3?), I agree with @DarkDimius that it would make sense
to hide the difference between strict and lazy vals. All vals are lazy,
but the memoization overhead is removed when we statically know they are forced during initialization.
We could still expose the low-level field semantics through private[this] val
s.
In any case, the current behavior of overriding vals is pretty surprising. An overridden val's side-effect is still performed. The only change due to overriding is that its value is never written to the field (the overridden val's value is, of course, stored in the field in addition to its side-effect being performed).
TODO: Java 9 support for vals defined in traits. They are currently emitted as final, but the write (putfield) to the val does not occur syntactically within the <init> method (it's done by the trait setter, which is called from the trait's mixin constructor, which is called from the subclass's constructor...)
- Source
- Fields.scala
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- Fields
- AccessorSynthesis
- TypingTransformers
- TreeDSL
- InfoTransform
- Transform
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- by StringFormat
- by Ensuring
- by ArrowAssoc
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- Public
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Instance Constructors
- new Fields()
Type Members
-
abstract
class
StdPhase extends GlobalPhase
A standard phase template
A standard phase template
- Definition Classes
- SubComponent
-
trait
AccessorTreeSynthesis extends AnyRef
- Definition Classes
- AccessorSynthesis
-
case class
BitmapInfo(symbol: Global.Symbol, mask: Global.Literal) extends Product with Serializable
- Definition Classes
- AccessorSynthesis
-
class
CheckedAccessorSymbolSynth extends AnyRef
- Definition Classes
- AccessorSynthesis
-
trait
CheckedAccessorTreeSynthesis extends AccessorTreeSynthesis
- Definition Classes
- AccessorSynthesis
- class FieldMemoization extends AnyRef
- class FieldsTransformer extends TypingTransformer with CheckedAccessorTreeSynthesis
-
class
Phase extends InfoTransform.Phase
- Definition Classes
- InfoTransform
-
abstract
class
ThicketTransformer extends TypingTransformer
A base class for typing transformers that need to perform "thicket expansion".
A base class for typing transformers that need to perform "thicket expansion". A thicket is the output of a transformation that is flattened into the enclosing block.
- Definition Classes
- TypingTransformers
-
abstract
class
TypingTransformer extends Global.Transformer
- Definition Classes
- TypingTransformers
Abstract Value Members
-
abstract
val
global: Global
- Definition Classes
- TypingTransformers
-
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
-
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
-
object
CODE
- Definition Classes
- TreeDSL
-
final
def
!=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
-
final
def
##(): Int
- Definition Classes
- AnyRef → Any
- def +(other: String): String
- def ->[B](y: B): (Fields, B)
-
final
def
==(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
-
val
EmptyThicket: Global.EmptyTree.type
- Definition Classes
- AccessorSynthesis
- final val TRAIT_SETTER_FLAGS: Long
-
def
Thicket(trees: List[Global.Tree]): Global.TermTree with Serializable
- Definition Classes
- AccessorSynthesis
-
final
def
afterOwnPhase[T](op: ⇒ T): T
- Definition Classes
- SubComponent
- Annotations
- @inline()
-
final
def
asInstanceOf[T0]: T0
- Definition Classes
- Any
-
final
def
beforeOwnPhase[T](op: ⇒ T): T
- Definition Classes
- SubComponent
- Annotations
- @inline()
- def castHack(tree: Global.Tree, pt: Global.Type): Global.Tree
-
def
changesBaseClasses: Boolean
- Attributes
- protected
- Definition Classes
- InfoTransform
- def checkAndClear(flag: Long)(sym: Global.Symbol): Boolean
- def checkAndClearNeedsTrees(setter: Global.Symbol): Boolean
- def checkAndClearOverriddenTraitSetter(setter: Global.Symbol): Boolean
-
def
checkedAccessorSymbolSynth(clz: Global.Symbol): CheckedAccessorSymbolSynth
- Definition Classes
- AccessorSynthesis
-
def
clone(): AnyRef
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws( ... ) @native()
- def dropFieldAnnotationsFromGetter(sym: Global.Symbol): Global.Symbol
-
def
enabled: Boolean
Is this component enabled? Default is true.
Is this component enabled? Default is true.
- Definition Classes
- SubComponent
- def ensuring(cond: (Fields) ⇒ Boolean, msg: ⇒ Any): Fields
- def ensuring(cond: (Fields) ⇒ Boolean): Fields
- def ensuring(cond: Boolean, msg: ⇒ Any): Fields
- def ensuring(cond: Boolean): Fields
-
final
def
eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
-
def
equals(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
-
def
explodeThicket(tree: Global.Tree): List[Global.Tree]
- Definition Classes
- AccessorSynthesis
- def fieldMemoizationIn(accessorOrField: Global.Symbol, site: Global.Symbol): FieldMemoization
- def fieldTypeOfAccessorIn(accessor: Global.Symbol, pre: Global.Type): Global.Type
-
def
finalize(): Unit
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws( classOf[java.lang.Throwable] )
-
final
def
getClass(): Class[_]
- Definition Classes
- AnyRef → Any
- Annotations
- @native()
- def getterTreeAnnotationsTargetFieldAndGetter(owner: Global.Symbol, mods: Global.Modifiers): Boolean
-
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
- Definition Classes
- SubComponent → AnyRef → Any
-
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
-
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
-
final
def
isInstanceOf[T0]: Boolean
- Definition Classes
- Any
-
def
keepsTypeParams: Boolean
- Attributes
- protected
- Definition Classes
- InfoTransform
- def lazyVarOf(sym: Global.Symbol): Global.Symbol
- def matchingAccessor(pre: Global.Type, member: Global.Symbol, clazz: Global.Symbol): Global.Symbol
-
def
mustExplodeThicket(tree: Global.Tree): Boolean
- Definition Classes
- AccessorSynthesis
-
final
def
ne(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
-
def
newPhase(prev: nsc.Phase): StdPhase
Create a new phase which applies transformer
Create a new phase which applies transformer
- Definition Classes
- InfoTransform → Transform → SubComponent
-
def
newRootLocalTyper(unit: Global.CompilationUnit): (analyzer)#Typer
- Attributes
- protected
- Definition Classes
- TypingTransformers
-
def
newTransformer(unit: Global.CompilationUnit): Global.Transformer
The transformer factory
- def nonStaticModuleToMethod(module: Global.Symbol): Unit
-
final
def
notDeferredOrSynthImpl(sym: Global.Symbol): Boolean
- Annotations
- @inline()
-
final
def
notify(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native()
-
final
def
notifyAll(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native()
-
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
-
val
phaseName: String
the following two members override abstract members in Transform
the following two members override abstract members in Transform
- Definition Classes
- Fields → SubComponent
-
def
phaseNewFlags: Long
New flags defined by the phase which are not valid before
New flags defined by the phase which are not valid before
- Definition Classes
- Fields → SubComponent
-
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
-
val
requires: List[String]
Names of phases required by this component.
Names of phases required by this component. Default is
Nil
.- Definition Classes
- SubComponent
-
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
- def symbolAnnotationsTargetFieldAndGetter(sym: Global.Symbol): Boolean
-
final
def
synchronized[T0](arg0: ⇒ T0): T0
- Definition Classes
- AnyRef
-
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
-
def
toString(): String
- Definition Classes
- AnyRef → Any
-
def
transformInfo(sym: Global.Symbol, tp: Global.Type): Global.Type
- Definition Classes
- Fields → InfoTransform
-
final
def
wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... ) @native()
- def →[B](y: B): (Fields, B)
Deprecated Value Members
-
def
formatted(fmtstr: String): String
- Implicit
- This member is added by an implicit conversion from Fields to StringFormat[Fields] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.12.16) Use
formatString.format(value)
instead ofvalue.formatted(formatString)
, or use thef""
string interpolator. In Java 15 and later,formatted
resolves to the new method in String which has reversed parameters.
The Scala compiler and reflection APIs.