package dotty.tools
package dotc
package core
import Decorators._
import Periods._
import Names._
import Phases._
import Types._
import Symbols._
import Scopes._
import NameOps._
import Uniques._
import SymDenotations._
import util.Positions._
import ast.Trees._
import ast.untpd
import util.{FreshNameCreator, SimpleMap, SourceFile, NoSource}
import typer._
import Implicits.ContextualImplicits
import config.Settings._
import reporting._
import collection.mutable
import collection.immutable.BitSet
import printing._
import config.{Settings, ScalaSettings, Platform, JavaPlatform}
import language.implicitConversions
import DenotTransformers.DenotTransformer
object Contexts {
/** A context is passed basically everywhere in dotc.
* This is convenient but carries the risk of captured contexts in
* objects that turn into space leaks. To combat this risk, here are some
* conventions to follow:
*
* - Never let an implicit context be an argument of a class whose instances
* live longer than the context.
* - Classes that need contexts for their initialization take an explicit parameter
* named `initctx`. They pass initctx to all positions where it is needed
* (and these positions should all be part of the intialization sequence of the class).
* - Classes that need contexts that survive initialization are instead passed
* a "condensed context", typically named `cctx` (or they create one). Consensed contexts
* just add some basic information to the context base without the
* risk of capturing complete trees.
* - To make sure these rules are kept, it would be good to do a sanity
* check using bytecode inspection with javap or scalap: Keep track
* of all class fields of type context; allow them only in whitelisted
* classes (which should be short-lived).
*/
abstract class Context extends Periods
with Substituters
with TypeOps
with Phases
with Printers
with Symbols
with SymDenotations
with Reporting
with NamerContextOps
with Cloneable { thiscontext =>
implicit def ctx: Context = this
/** The context base at the root */
val base: ContextBase
/** All outer contexts, ending in `base.initialCtx` and then `NoContext` */
def outersIterator = new Iterator[Context] {
var current = thiscontext
def hasNext = current != NoContext
def next = { val c = current; current = current.outer; c }
}
/** The outer context */
private[this] var _outer: Context = _
protected def outer_=(outer: Context) = _outer = outer
def outer: Context = _outer
/** The current context */
private[this] var _period: Period = _
protected def period_=(period: Period) = _period = period
def period: Period = _period
/** The scope nesting level */
private[this] var _mode: Mode = _
protected def mode_=(mode: Mode) = _mode = mode
def mode: Mode = _mode
/** The current type comparer */
private[this] var _typerState: TyperState = _
protected def typerState_=(typerState: TyperState) = _typerState = typerState
def typerState: TyperState = _typerState
/** The current plain printer */
private[this] var _printerFn: Context => Printer = _
protected def printerFn_=(printerFn: Context => Printer) = _printerFn = printerFn
def printerFn: Context => Printer = _printerFn
/** The current owner symbol */
private[this] var _owner: Symbol = _
protected def owner_=(owner: Symbol) = _owner = owner
def owner: Symbol = _owner
/** The current settings values */
private[this] var _sstate: SettingsState = _
protected def sstate_=(sstate: SettingsState) = _sstate = sstate
def sstate: SettingsState = _sstate
/** The current tree */
private[this] var _compilationUnit: CompilationUnit = _
protected def compilationUnit_=(compilationUnit: CompilationUnit) = _compilationUnit = compilationUnit
def compilationUnit: CompilationUnit = _compilationUnit
/** The current tree */
private[this] var _tree: Tree[_ >: Untyped] = _
protected def tree_=(tree: Tree[_ >: Untyped]) = _tree = tree
def tree: Tree[_ >: Untyped] = _tree
/** The current scope */
private[this] var _scope: Scope = _
protected def scope_=(scope: Scope) = _scope = scope
def scope: Scope = _scope
/** The current type assigner ot typer */
private[this] var _typeAssigner: TypeAssigner = _
protected def typeAssigner_=(typeAssigner: TypeAssigner) = _typeAssigner = typeAssigner
def typeAssigner: TypeAssigner = _typeAssigner
def typer: Typer = _typeAssigner.asInstanceOf[Typer]
/** The currently active import info */
private[this] var _importInfo: ImportInfo = _
protected def importInfo_=(importInfo: ImportInfo) = _importInfo = importInfo
def importInfo: ImportInfo = _importInfo
/** The current compiler-run specific Info */
private[this] var _runInfo: RunInfo = _
protected def runInfo_=(runInfo: RunInfo) = _runInfo = runInfo
def runInfo: RunInfo = _runInfo
/** An optional diagostics buffer than is used by some checking code
* to provide more information in the buffer if it exists.
*/
private var _diagnostics: Option[StringBuilder] = _
protected def diagnostics_=(diagnostics: Option[StringBuilder]) = _diagnostics = diagnostics
def diagnostics: Option[StringBuilder] = _diagnostics
/** A map in which more contextual properties can be stored */
private var _moreProperties: Map[String, Any] = _
protected def moreProperties_=(moreProperties: Map[String, Any]) = _moreProperties = moreProperties
def moreProperties: Map[String, Any] = _moreProperties
private var _typeComparer: TypeComparer = _
protected def typeComparer_=(typeComparer: TypeComparer) = _typeComparer = typeComparer
def typeComparer: TypeComparer = {
if (_typeComparer.ctx ne this)
_typeComparer = _typeComparer.copyIn(this)
_typeComparer
}
/** The new implicit references that are introduced by this scope */
private var implicitsCache: ContextualImplicits = null
def implicits: ContextualImplicits = {
if (implicitsCache == null )
implicitsCache = {
val implicitRefs: List[TermRef] =
if (isClassDefContext) owner.thisType.implicitMembers
else if (isImportContext) importInfo.importedImplicits
else if (isNonEmptyScopeContext) scope.implicitDecls
else Nil
val outerImplicits =
if (isImportContext && importInfo.hiddenRoot.exists)
outer.implicits exclude importInfo.hiddenRoot
else
outer.implicits
if (implicitRefs.isEmpty) outerImplicits
else new ContextualImplicits(implicitRefs, outerImplicits)(this)
}
implicitsCache
}
/** The history of implicit searches that are currently active */
private var _searchHistory: SearchHistory = null
protected def searchHistory_= (searchHistory: SearchHistory) = _searchHistory = searchHistory
def searchHistory: SearchHistory = _searchHistory
private var phasedCtx: Context = _
private var phasedCtxs: Array[Context] = _
/** This context at given phase.
* This method will always return a phase period equal to phaseId, thus will never return squashed phases
*/
final def withPhase(phaseId: PhaseId): Context = {
if (this.phaseId == phaseId) this
else if (phasedCtx.phaseId == phaseId) phasedCtx
else if (phasedCtxs != null && phasedCtxs(phaseId) != null) phasedCtxs(phaseId)
else {
val ctx1 = fresh.setPhase(phaseId)
if (phasedCtx eq this) phasedCtx = ctx1
else {
if (phasedCtxs == null) phasedCtxs = new Array[Context](base.phases.length)
phasedCtxs(phaseId) = ctx1
}
ctx1
}
}
final def withPhase(phase: Phase): Context =
withPhase(phase.id)
/** If -Ydebug is on, the top of the stack trace where this context
* was created, otherwise `null`.
*/
private var creationTrace: Array[StackTraceElement] = _
private def setCreationTrace() =
if (this.settings.debug.value)
creationTrace = (new Throwable).getStackTrace().take(20)
/** Print all enclosing context's creation stacktraces */
def printCreationTraces() = {
println("=== context creation trace =======")
for (ctx <- outersIterator) {
println(s">>>>>>>>> $ctx")
if (ctx.creationTrace != null) println(ctx.creationTrace.mkString("\n"))
}
println("=== end context creation trace ===")
}
/** The current reporter */
def reporter: Reporter = typerState.reporter
/** Is this a context for the members of a class definition? */
def isClassDefContext: Boolean =
owner.isClass && (owner ne outer.owner)
/** Is this a context that introduces an import clause? */
def isImportContext: Boolean =
(this ne NoContext) && (this.importInfo ne outer.importInfo)
/** Is this a context that introduces a non-empty scope? */
def isNonEmptyScopeContext: Boolean =
(this.scope ne outer.scope) && this.scope.nonEmpty
/** Leave message in diagnostics buffer if it exists */
def diagnose(str: => String) =
for (sb <- diagnostics) {
sb.setLength(0)
sb.append(str)
}
/** The next outer context whose tree is a template or package definition */
def enclTemplate: Context = {
var c = this
while (c != NoContext && !c.tree.isInstanceOf[Template[_]] && !c.tree.isInstanceOf[PackageDef[_]])
c = c.outer
c
}
/** The current source file; will be derived from current
* compilation unit.
*/
def source: SourceFile =
if (compilationUnit == null) NoSource else compilationUnit.source
/** Does current phase use an erased types interpretation? */
def erasedTypes: Boolean = phase.erasedTypes
/** Is the debug option set? */
def debug: Boolean = base.settings.debug.value
/** Is the verbose option set? */
def verbose: Boolean = base.settings.verbose.value
/** A condensed context containing essential information of this but
* no outer contexts except the initial context.
private var _condensed: CondensedContext = null
def condensed: CondensedContext = {
if (_condensed eq outer.condensed)
_condensed = base.initialCtx.fresh
.withPeriod(period)
.withNewMode(mode)
// typerState and its constraint is not preserved in condensed
// reporter is always ThrowingReporter
.withPrinterFn(printerFn)
.withOwner(owner)
.withSettings(sstate)
// tree is not preserved in condensed
.withRunInfo(runInfo)
.withDiagnostics(diagnostics)
.withMoreProperties(moreProperties)
_condensed
}
*/
protected def init(outer: Context): this.type = {
this.outer = outer
this.implicitsCache = null
this.phasedCtx = this
this.phasedCtxs = null
setCreationTrace()
this
}
/** A fresh clone of this context. */
def fresh: FreshContext = clone.asInstanceOf[FreshContext].init(this)
final def withOwner(owner: Symbol): Context =
if (owner ne this.owner) fresh.setOwner(owner) else this
final def withMode(mode: Mode): Context =
if (mode != this.mode) fresh.setMode(mode) else this
final def addMode(mode: Mode): Context = withMode(this.mode | mode)
final def maskMode(mode: Mode): Context = withMode(this.mode & mode)
final def retractMode(mode: Mode): Context = withMode(this.mode &~ mode)
override def toString =
"Context(\n" +
(outersIterator map ( ctx => s" owner = ${ctx.owner}, scope = ${ctx.scope}") mkString "\n")
}
/** A condensed context provides only a small memory footprint over
* a Context base, and therefore can be stored without problems in
* long-lived objects.
abstract class CondensedContext extends Context {
override def condensed = this
}
*/
/** A fresh context allows selective modification
* of its attributes using the with... methods.
*/
abstract class FreshContext extends Context {
def setPeriod(period: Period): this.type = { this.period = period; this }
def setMode(mode: Mode): this.type = { this.mode = mode; this }
def setTyperState(typerState: TyperState): this.type = { this.typerState = typerState; this }
def setNewTyperState: this.type = setTyperState(typerState.fresh(isCommittable = true))
def setExploreTyperState: this.type = setTyperState(typerState.fresh(isCommittable = false))
def setPrinterFn(printer: Context => Printer): this.type = { this.printerFn = printer; this }
def setOwner(owner: Symbol): this.type = { assert(owner != NoSymbol); this.owner = owner; this }
def setSettings(sstate: SettingsState): this.type = { this.sstate = sstate; this }
def setCompilationUnit(compilationUnit: CompilationUnit): this.type = { this.compilationUnit = compilationUnit; this }
def setTree(tree: Tree[_ >: Untyped]): this.type = { this.tree = tree; this }
def setScope(scope: Scope): this.type = { this.scope = scope; this }
def setNewScope: this.type = { this.scope = newScope; this }
def setTypeAssigner(typeAssigner: TypeAssigner): this.type = { this.typeAssigner = typeAssigner; this }
def setTyper(typer: Typer): this.type = { this.scope = typer.scope; setTypeAssigner(typer) }
def setImportInfo(importInfo: ImportInfo): this.type = { this.importInfo = importInfo; this }
def setRunInfo(runInfo: RunInfo): this.type = { this.runInfo = runInfo; this }
def setDiagnostics(diagnostics: Option[StringBuilder]): this.type = { this.diagnostics = diagnostics; this }
def setTypeComparerFn(tcfn: Context => TypeComparer): this.type = { this.typeComparer = tcfn(this); this }
def setSearchHistory(searchHistory: SearchHistory): this.type = { this.searchHistory = searchHistory; this }
def setMoreProperties(moreProperties: Map[String, Any]): this.type = { this.moreProperties = moreProperties; this }
def setProperty(prop: (String, Any)): this.type = setMoreProperties(moreProperties + prop)
def setPhase(pid: PhaseId): this.type = setPeriod(Period(runId, pid))
def setPhase(phase: Phase): this.type = setPeriod(Period(runId, phase.start, phase.end))
def setSetting[T](setting: Setting[T], value: T): this.type =
setSettings(setting.updateIn(sstate, value))
def setDebug = setSetting(base.settings.debug, true)
}
/** A class defining the initial context with given context base
* and set of possible settings.
*/
private class InitialContext(val base: ContextBase, settings: SettingGroup) extends FreshContext {
outer = NoContext
period = InitialPeriod
mode = Mode.None
typerState = new TyperState(new ThrowingReporter(new ConsoleReporter()(this)))
printerFn = new RefinedPrinter(_)
owner = NoSymbol
sstate = settings.defaultState
tree = untpd.EmptyTree
typeAssigner = TypeAssigner
runInfo = new RunInfo(this)
diagnostics = None
moreProperties = Map.empty
typeComparer = new TypeComparer(this)
searchHistory = new SearchHistory(0, Map())
}
object NoContext extends Context {
lazy val base = unsupported("base")
override val implicits: ContextualImplicits = new ContextualImplicits(Nil, null)(this)
}
/** A context base defines state and associated methods that exist once per
* compiler run.
*/
class ContextBase extends ContextState
with Denotations.DenotationsBase
with Phases.PhasesBase {
/** The applicable settings */
val settings = new ScalaSettings
/** The initial context */
val initialCtx: Context = new InitialContext(this, settings)
/** The symbol loaders */
val loaders = new SymbolLoaders
/** The platform */
val platform: Platform = new JavaPlatform
/** The standard fresh name creator */
val freshNames = new FreshNameCreator.Default
def freshName(prefix: String = ""): String = freshNames.newName(prefix)
def freshName(prefix: Name): String = freshName(prefix.toString)
/** The loader that loads the members of _root_ */
def rootLoader(root: TermSymbol)(implicit ctx: Context): SymbolLoader = platform.rootLoader(root)
// Set up some phases to get started */
usePhases(List(List(SomePhase)))
/** The standard definitions */
val definitions = new Definitions
}
/** The essential mutable state of a context base, collected into a common class */
class ContextState {
// Symbols state
/** A counter for unique ids */
private[core] var _nextId = 0
def nextId = { _nextId += 1; _nextId }
/** A map from a superclass id to the typeref of the class that has it */
private[core] var classOfId = new Array[ClassSymbol](InitialSuperIdsSize)
/** A map from a the typeref of a class to its superclass id */
private[core] val superIdOfClass = new mutable.AnyRefMap[ClassSymbol, Int]
/** The last allocated superclass id */
private[core] var lastSuperId = -1
/** Allocate and return next free superclass id */
private[core] def nextSuperId: Int = {
lastSuperId += 1
if (lastSuperId >= classOfId.length) {
val tmp = new Array[ClassSymbol](classOfId.length * 2)
classOfId.copyToArray(tmp)
classOfId = tmp
}
lastSuperId
}
// Types state
/** A table for hash consing unique types */
private[core] val uniques = new util.HashSet[Type](initialUniquesCapacity) {
override def hash(x: Type): Int = x.hash
}
/** A table for hash consing unique refined types */
private[dotc] val uniqueRefinedTypes = new RefinedUniques
/** A table for hash consing unique named types */
private[core] val uniqueNamedTypes = new NamedTypeUniques
/** A table for hash consing unique type bounds */
private[core] val uniqueTypeBounds = new TypeBoundsUniques
private def uniqueSets = Map(
"uniques" -> uniques,
"uniqueRefinedTypes" -> uniqueRefinedTypes,
"uniqueNamedTypes" -> uniqueNamedTypes,
"uniqueTypeBounds" -> uniqueTypeBounds)
/** A map that associates label and size of all uniques sets */
def uniquesSizes: Map[String, Int] = uniqueSets.mapValues(_.size)
/** The number of recursive invocation of underlying on a NamedType
* during a controlled operation.
*/
private[core] var underlyingRecursions: Int = 0
/** The set of named types on which a currently active invocation
* of underlying during a controlled operation exists. */
private[core] val pendingUnderlying = new mutable.HashSet[Type]
// Phases state
/** Phases by id */
private[core] var phases: Array[Phase] = _
/** Phases with consecutive Transforms groupped into a single phase */
private [core] var squashedPhases: Array[Phase] = _
/** Next denotation transformer id */
private[core] var nextDenotTransformerId: Array[Int] = _
private[core] var denotTransformers: Array[DenotTransformer] = _
// Printers state
/** Number of recursive invocations of a show method on cuyrrent stack */
private[dotc] var toTextRecursions = 0
// Reporters state
private[dotc] var indent = 0
protected[dotc] val indentTab = " "
/** Should warnings and errors containing non-sensical strings be suppressed? */
private[dotc] var suppressNonSensicalErrors = true
def reset() = {
for ((_, set) <- uniqueSets) set.clear()
for (i <- 0 until classOfId.length) classOfId(i) = null
superIdOfClass.clear()
lastSuperId = -1
}
}
object Context {
/** Implicit conversion that injects all printer operations into a context */
implicit def toPrinter(ctx: Context): Printer = ctx.printer
/** implicit conversion that injects all ContextBase members into a context */
implicit def toBase(ctx: Context): ContextBase = ctx.base
val theBase = new ContextBase // !!! DEBUG, so that we can use a minimal context for reporting even in code that normallly cannot access a context
}
/** Info that changes on each compiler run */
class RunInfo(initctx: Context) extends ImplicitRunInfo with ConstraintRunInfo {
implicit val ctx: Context = initctx
}
/** Initial size of superId table */
private final val InitialSuperIdsSize = 4096
/** Initial capacity of uniques HashMap */
private[core] final val initialUniquesCapacity = 40000
/** How many recursive calls to NamedType#underlying are performed before
* logging starts.
*/
private[core] final val LogPendingUnderlyingThreshold = 50
/** How many recursive calls to isSubType are performed before
* logging starts.
*/
private[core] final val LogPendingSubTypesThreshold = 50
}
