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Copyright (c) 2002-2023, LAMP/EPFL
scala3-compiler-bootstrapped/dotty.tools/dotty.tools.dotc/dotty.tools.dotc.transform/LazyVals

LazyVals

dotty.tools.dotc.transform.LazyVals
See theLazyVals companion object
class LazyVals extends MiniPhase, IdentityDenotTransformer

Attributes

Companion
object
Graph
Supertypes
class MiniPhase
class Phase
class Object
trait Matchable
class Any
Show all

Members list

Type members

Classlikes

class OffsetInfo(var defs: List[Tree], var ord: Int)

The map contains the list of the offset trees.

The map contains the list of the offset trees.

Attributes

Supertypes
class Object
trait Matchable
class Any

Value members

Concrete methods

override def changesMembers: Boolean

Can this transform create or delete non-private members?

Can this transform create or delete non-private members?

Attributes

Definition Classes
override def description: String

Attributes

Definition Classes
def mkDefThreadUnsafeNonNullable(sym: Symbol, target: Symbol, rhs: Tree)(using Context): DefDef

Create thread-unsafe lazy accessor for not-nullable types equivalent to such code

Create thread-unsafe lazy accessor for not-nullable types equivalent to such code

def methodSymbol() = {
 if (target eq null) {
   target = rhs
   nullable = null
 }
 target
}

Attributes

def mkThreadSafeDef(memberDef: ValOrDefDef, claz: ClassSymbol, target: Symbol, offset: Tree, thiz: Tree)(using Context): (DefDef, DefDef)

Create a threadsafe lazy accessor and function that computes the field's value. Evaluating and NullValue are represented by objects and Waiting by a class that allows awaiting the completion of the evaluation. Note that since tail-recursive functions are transformed before lazy-vals, this implementation does involve explicit while loop. PatternMatcher is coming before LazyVals, therefore the pattern matching is implemented using if-s.

Create a threadsafe lazy accessor and function that computes the field's value. Evaluating and NullValue are represented by objects and Waiting by a class that allows awaiting the completion of the evaluation. Note that since tail-recursive functions are transformed before lazy-vals, this implementation does involve explicit while loop. PatternMatcher is coming before LazyVals, therefore the pattern matching is implemented using if-s.

private @volatile var _x: AnyRef = null

def x: A =
 val result = _x
 if result.isInstanceOf[A] then
   result // possible unboxing applied here
 else if result.eq(NullValue) then
   null // possible unboxing applied here
 else
   x_compute() // possible unboxing applied here

private def x_compute(): AnyRef =
 while <EmptyTree> do
   val current: AnyRef = _x
   if current.eq(null) then
     if CAS(_x, null, Evaluating) then
       var resultNullable: AnyRef = null
       var result: AnyRef = null
       try
         resultNullable = rhs
         nullable = null // nulls out the nullable fields used only in initialization
         if resultNullable.eq(null) then
           result = NullValue
         else
           result = resultNullable
       finally
          if !CAS(_x, Evaluating, result) then
            val lock = _x.asInstanceOf[Waiting]
            CAS(_x, lock, result)
            lock.release()
       return resultNullable
   else
     if current.isInstanceOf[LazyValControlState] then
       if current.eq(Evaluating) then // To avoid creating Waiting instance
         CAS(current, current, new Waiting)
       else if current.isInstanceOf[Waiting] then
         current.asInstanceOf[Waiting].await()
       else return null
     else
       return current
 end while
*

Value parameters

claz

the class containing this lazy val field

memberDef

the transformed lazy field member definition

offset

the offset of the field in the storage allocation of the class

target

the target synthetic field

thiz

a reference to the transformed class

Attributes

def mkThreadSafeDefLegacy(methodSymbol: TermSymbol, claz: ClassSymbol, ord: Int, target: Symbol, rhs: Tree, tp: Type, offset: Tree, getFlag: Tree, stateMask: Tree, casFlag: Tree, setFlagState: Tree, waitOnLock: Tree)(using Context): DefDef

Create a threadsafe lazy accessor equivalent to such code

Create a threadsafe lazy accessor equivalent to such code

def methodSymbol(): Int = {
 while (true) {
   val flag = LazyVals.get(this, bitmap_offset)
   val state = LazyVals.STATE(flag, <field-id>)

   if (state == <state-3>) {
     return value_0
   } else if (state == <state-0>) {
     if (LazyVals.CAS(this, bitmap_offset, flag, <state-1>, <field-id>)) {
       try {
         val result = <RHS>
         value_0 = result
         nullable = null
         LazyVals.setFlag(this, bitmap_offset, <state-3>, <field-id>)
         return result
       }
       catch {
         case ex =>
           LazyVals.setFlag(this, bitmap_offset, <state-0>, <field-id>)
           throw ex
       }
     }
   } else /* if (state == <state-1> || state == <state-2>) */ {
     LazyVals.wait4Notification(this, bitmap_offset, flag, <field-id>)
   }
 }
}

Attributes

def mkThreadUnsafeDef(sym: Symbol, flag: Symbol, target: Symbol, rhs: Tree)(using Context): DefDef

Create thread-unsafe lazy accessor equivalent to such code

Create thread-unsafe lazy accessor equivalent to such code

def methodSymbol() = {
 if (!flag) {
   target = rhs
   flag = true
   nullable = null
 }
 target
}

Attributes

override def phaseName: String

A name given to the Phase that can be used to debug the compiler. For instance, it is possible to print trees after a given phase using:

A name given to the Phase that can be used to debug the compiler. For instance, it is possible to print trees after a given phase using:

$ ./bin/scalac -Xprint:<phaseNameHere> sourceFile.scala

Attributes

Definition Classes
override def prepareForUnit(tree: Tree)(using Context): Context

Attributes

Definition Classes
override def runsAfter: Set[String]

List of names of phases that should have finished processing of tree before this phase starts processing same tree

List of names of phases that should have finished processing of tree before this phase starts processing same tree

Attributes

Definition Classes
override def transformDefDef(tree: DefDef)(using Context): Tree

Attributes

Definition Classes
def transformLocalDef(x: ValOrDefDef)(using Context): Thicket

Desugar a local lazy val x: Int = <RHS> into:

Desugar a local lazy val x: Int = <RHS> into:

val x$lzy = new scala.runtime.LazyInt()

def x$lzycompute(): Int = x$lzy.synchronized {
  if (x$lzy.initialized()) x$lzy.value()
  else x$lzy.initialize(<RHS>)
    // TODO: Implement Unit-typed lazy val optimization described below
    // for a Unit-typed lazy val, this becomes `{ rhs ; x$lzy.initialize() }`
    // to avoid passing around BoxedUnit
}

def x(): Int = if (x$lzy.initialized()) x$lzy.value() else x$lzycompute()

Attributes

override def transformStats(trees: List[Tree])(using Context): List[Tree]

Attributes

Definition Classes
def transformSyntheticModule(tree: ValOrDefDef)(using Context): Thicket

Make an eager val that would implement synthetic module. Eager val ensures thread safety and has less code generated.

Make an eager val that would implement synthetic module. Eager val ensures thread safety and has less code generated.

Attributes

override def transformTemplate(template: Template)(using Context): Tree

Append offset fields to companion objects

Append offset fields to companion objects

Attributes

Definition Classes
override def transformValDef(tree: ValDef)(using Context): Tree

Attributes

Definition Classes

Inherited methods

final def <=(that: Phase): Boolean

Attributes

Inherited from:
Phase
def allowsImplicitSearch: Boolean

If set, implicit search is enabled

If set, implicit search is enabled

Attributes

Inherited from:
Phase
def changesBaseTypes: Boolean

Can this transform change the base types of a type?

Can this transform change the base types of a type?

Attributes

Inherited from:
Phase
def changesParents: Boolean

Can this transform change the parents of a class?

Can this transform change the parents of a class?

Attributes

Inherited from:
Phase
def checkPostCondition(tree: Tree)(using Context): Unit

Check what the phase achieves, to be called at any point after it is finished.

Check what the phase achieves, to be called at any point after it is finished.

Attributes

Inherited from:
Phase
def end: PhaseId

Attributes

Inherited from:
Phase
final def erasedTypes: Boolean

Attributes

Inherited from:
Phase
def exists: Boolean

Attributes

Inherited from:
Phase
final def flatClasses: Boolean

Attributes

Inherited from:
Phase
final def hasNext: Boolean

Attributes

Inherited from:
Phase
def id: Int

The sequence position of this phase in the given context where 0 is reserved for NoPhase and the first real phase is at position 1. -1 if the phase is not installed in the context.

The sequence position of this phase in the given context where 0 is reserved for NoPhase and the first real phase is at position 1. -1 if the phase is not installed in the context.

Attributes

Inherited from:
Phase
def initContext(ctx: FreshContext): Unit

Attributes

Inherited from:
Phase
def isCheckable: Boolean

Output should be checkable by TreeChecker

Output should be checkable by TreeChecker

Attributes

Inherited from:
Phase
def isEnabled(using Context): Boolean

Attributes

Inherited from:
Phase
def isRunnable(using Context): Boolean

Attributes

Inherited from:
Phase
def isTyper: Boolean

Is this phase the standard typerphase? True for TyperPhase, but not for other first phases (such as FromTasty or Parser). The predicate is tested in some places that perform checks and corrections. It's different from ctx.isAfterTyper (and cheaper to test).

Is this phase the standard typerphase? True for TyperPhase, but not for other first phases (such as FromTasty or Parser). The predicate is tested in some places that perform checks and corrections. It's different from ctx.isAfterTyper (and cheaper to test).

Attributes

Inherited from:
Phase
final def iterator: Iterator[Phase]

Attributes

Inherited from:
Phase
final def lambdaLifted: Boolean

Attributes

Inherited from:
Phase
def lastPhaseId(using Context): Int

The last phase during which the transformed denotations are valid

The last phase during which the transformed denotations are valid

Attributes

Inherited from:
DenotTransformer
final def megaPhase(using Context): Phase

Attributes

Inherited from:
Phase
final def monitor(doing: String)(body: => Unit)(using Context): Unit

Attributes

Inherited from:
Phase
final def next: Phase

Attributes

Inherited from:
Phase
final def patternTranslated: Boolean

Attributes

Inherited from:
Phase
def period: Period

Attributes

Inherited from:
Phase
def prepareForAlternative(tree: Alternative)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForApply(tree: Apply)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForAssign(tree: Assign)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForBind(tree: Bind)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForBlock(tree: Block)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForCaseDef(tree: CaseDef)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForClosure(tree: Closure)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForDefDef(tree: DefDef)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForIdent(tree: Ident)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForIf(tree: If)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForInlined(tree: Inlined)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForLabeled(tree: Labeled)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForLiteral(tree: Literal)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForMatch(tree: Match)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForNew(tree: New)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForOther(tree: Tree)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForPackageDef(tree: PackageDef)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForQuote(tree: Quote)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForReturn(tree: Return)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForSelect(tree: Select)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForSeqLiteral(tree: SeqLiteral)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForSplice(tree: Splice)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForStats(trees: List[Tree])(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForSuper(tree: Super)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForTemplate(tree: Template)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForThis(tree: This)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForTry(tree: Try)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForTypeApply(tree: TypeApply)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForTypeDef(tree: TypeDef)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForTypeTree(tree: TypeTree)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForTyped(tree: Typed)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForUnApply(tree: UnApply)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForValDef(tree: ValDef)(using Context): Context

Attributes

Inherited from:
MiniPhase
def prepareForWhileDo(tree: WhileDo)(using Context): Context

Attributes

Inherited from:
MiniPhase
final def prev: Phase

Attributes

Inherited from:
Phase
final def refChecked: Boolean

Attributes

Inherited from:
Phase
final override def relaxedTyping: Boolean

If set, allow missing or superfluous arguments in applications and type applications.

If set, allow missing or superfluous arguments in applications and type applications.

Attributes

Definition Classes
Inherited from:
MiniPhase
def relaxedTypingInGroup: Boolean

If set, use relaxed typing for all phases in group

If set, use relaxed typing for all phases in group

Attributes

Inherited from:
MiniPhase
override def run(using Context): Unit

Attributes

Definition Classes
Inherited from:
MiniPhase
def runOn(units: List[CompilationUnit])(using runCtx: Context): List[CompilationUnit]

Attributes

Inherited from:
Phase
def runsAfterGroupsOf: Set[String]

List of names of phases that should have finished their processing of all compilation units before this phase starts

List of names of phases that should have finished their processing of all compilation units before this phase starts

Attributes

Inherited from:
MiniPhase
final def sameBaseTypesStartId: Int

Attributes

Inherited from:
Phase
final def sameMembersStartId: Int

Attributes

Inherited from:
Phase
final def sameParentsStartId: Int

Attributes

Inherited from:
Phase
def show(tree: Tree)(using Context): String

Convert a compilation unit's tree to a string; can be overridden

Convert a compilation unit's tree to a string; can be overridden

Attributes

Inherited from:
Phase
protected def singletonGroup: MegaPhase

Attributes

Inherited from:
MiniPhase
def start: Int

Attributes

Inherited from:
Phase
override def toString: String

Returns a string representation of the object.

Returns a string representation of the object.

The default representation is platform dependent.

Attributes

Returns

a string representation of the object.

Definition Classes
Phase -> Any
Inherited from:
Phase
def transform(ref: SingleDenotation)(using Context): SingleDenotation

The transformation method

The transformation method

Attributes

Inherited from:
IdentityDenotTransformer
def transformAllDeep(tree: Tree)(using Context): Tree

Transform tree using all transforms of current group (including this one)

Transform tree using all transforms of current group (including this one)

Attributes

Inherited from:
MiniPhase
def transformAlternative(tree: Alternative)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformApply(tree: Apply)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformAssign(tree: Assign)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformBind(tree: Bind)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformBlock(tree: Block)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformCaseDef(tree: CaseDef)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformClosure(tree: Closure)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformFollowing(tree: Tree)(using Context): Tree

Transform single node using all transforms following the current one in this group

Transform single node using all transforms following the current one in this group

Attributes

Inherited from:
MiniPhase
def transformFollowingDeep(tree: Tree)(using Context): Tree

Transform tree using all transforms following the current one in this group

Transform tree using all transforms following the current one in this group

Attributes

Inherited from:
MiniPhase
def transformIdent(tree: Ident)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformIf(tree: If)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformInlined(tree: Inlined)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformLabeled(tree: Labeled)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformLiteral(tree: Literal)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformMatch(tree: Match)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformNew(tree: New)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformOther(tree: Tree)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformPackageDef(tree: PackageDef)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformQuote(tree: Quote)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformReturn(tree: Return)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformSelect(tree: Select)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformSeqLiteral(tree: SeqLiteral)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformSplice(tree: Splice)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformSuper(tree: Super)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformThis(tree: This)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformTry(tree: Try)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformTypeApply(tree: TypeApply)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformTypeDef(tree: TypeDef)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformTypeTree(tree: TypeTree)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformTyped(tree: Typed)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformUnApply(tree: UnApply)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformUnit(tree: Tree)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def transformWhileDo(tree: WhileDo)(using Context): Tree

Attributes

Inherited from:
MiniPhase
def validFor(using Context): Period

The validity period of the transformed denotations in the given context

The validity period of the transformed denotations in the given context

Attributes

Inherited from:
DenotTransformer

Concrete fields

Inherited fields

val cpy: TypedTreeCopier

Attributes

Inherited from:
MiniPhase
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Copyright (c) 2002-2023, LAMP/EPFL
Copyright (c) 2002-2023, LAMP/EPFL