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Document phases
Give a one-line explanation what each phase does in Compiler.
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‎src/dotty/tools/dotc/Compiler.scala

Lines changed: 49 additions & 48 deletions
Original file line numberDiff line numberDiff line change
@@ -38,54 +38,55 @@ class Compiler {
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*/
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def phases: List[List[Phase]] =
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List(
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List(new FrontEnd),
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List(new PostTyper),
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List(new Pickler),
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List(new FirstTransform,
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new CheckReentrant),
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List(new RefChecks,
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new CheckStatic,
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new ElimRepeated,
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new NormalizeFlags,
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new ExtensionMethods,
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new ExpandSAMs,
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new TailRec,
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new LiftTry,
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new ClassOf),
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List(new PatternMatcher,
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new ExplicitOuter,
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new ExplicitSelf,
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new CrossCastAnd,
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new Splitter),
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List(new VCInlineMethods,
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new SeqLiterals,
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new InterceptedMethods,
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new Getters,
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new ElimByName,
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new AugmentScala2Traits,
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new ResolveSuper),
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List(new Erasure),
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List(new ElimErasedValueType,
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new VCElideAllocations,
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new Mixin,
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new LazyVals,
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new Memoize,
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new LinkScala2ImplClasses,
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new NonLocalReturns,
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new CapturedVars, // capturedVars has a transformUnit: no phases should introduce local mutable vars here
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new Constructors, // constructors changes decls in transformTemplate, no InfoTransformers should be added after it
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new FunctionalInterfaces,
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new GetClass), // getClass transformation should be applied to specialized methods
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List(new LambdaLift, // in this mini-phase block scopes are incorrect. No phases that rely on scopes should be here
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new ElimStaticThis,
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new Flatten,
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// new DropEmptyCompanions,
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new RestoreScopes),
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List(new ExpandPrivate,
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new CollectEntryPoints,
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new LabelDefs),
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List(new GenSJSIR),
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List(new GenBCode)
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List(new FrontEnd), // Compiler frontend: scanner, parser, namer, typer
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List(new PostTyper), // Additional checks and cleanups after type checking
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List(new Pickler), // Generate TASTY info
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List(new FirstTransform, // Some transformations to put trees into a canonical form
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new CheckReentrant), // Internal use only: Check that compiled program has no data races involving global vars
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List(new RefChecks, // Various checks mostly related to abstract members and overriding
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new CheckStatic, // Check restrictions that apply to @static members
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new ElimRepeated, // Rewrite vararg parameters and arguments
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new NormalizeFlags, // Rewrite some definition flags
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new ExtensionMethods, // Expand methods of value classes with extension methods
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new ExpandSAMs, // Expand single abstract method closures to anonymous classes
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new TailRec, // Rewrite tail recursion to loops
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new LiftTry, // Put try expressions that might execute on non-empty stacks into their own methods
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new ClassOf), // Expand `Predef.classOf` calls.
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List(new PatternMatcher, // Compile pattern matches
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new ExplicitOuter, // Add accessors to outer classes from nested ones.
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new ExplicitSelf, // Make references to non-trivial self types explicit as casts
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new CrossCastAnd, // Normalize selections involving intersection types.
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new Splitter), // Expand selections involving union types into conditionals
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List(new VCInlineMethods, // Inlines calls to value class methods
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new SeqLiterals, // Express vararg arguments as arrays
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new InterceptedMethods, // Special handling of `==`, `|=`, `getClass` methods
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new Getters, // Replace non-private vals and vars with getter defs (fields are added later)
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new ElimByName, // Expand by-name parameters and arguments
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new AugmentScala2Traits, // Expand traits defined in Scala 2.11 to simulate old-style rewritings
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new ResolveSuper), // Implement super accessors and add forwarders to trait methods
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List(new Erasure), // Rewrite types to JVM model, erasing all type parameters, abstract types and refinements.
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List(new ElimErasedValueType, // Expand erased value types to their underlying implmementation types
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new VCElideAllocations, // Peep-hole optimization to eliminate unnecessary value class allocations
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new Mixin, // Expand trait fields and trait initializers
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new LazyVals, // Expand lazy vals
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new Memoize, // Add private fields to getters and setters
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new LinkScala2ImplClasses, // Forward calls to the implementation classes of traits defined by Scala 2.11
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new NonLocalReturns, // Expand non-local returns
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new CapturedVars, // Represent vars captured by closures as heap objects
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new Constructors, // Collect initialization code in primary constructors
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// Note: constructors changes decls in transformTemplate, no InfoTransformers should be added after it
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new FunctionalInterfaces,// Rewrites closures to implement @specialized types of Functions.
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new GetClass), // Rewrites getClass calls on primitive types.
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List(new LambdaLift, // Lifts out nested functions to class scope, storing free variables in environments
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// Note: in this mini-phase block scopes are incorrect. No phases that rely on scopes should be here
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new ElimStaticThis, // Replace `this` references to static objects by global identifiers
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new Flatten, // Lift all inner classes to package scope
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new RestoreScopes), // Repair scopes rendered invalid by moving definitions in prior phases of the group
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List(new ExpandPrivate, // Widen private definitions accessed from nested classes
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new CollectEntryPoints, // Find classes with main methods
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new LabelDefs), // Converts calls to labels to jumps
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List(new GenSJSIR), // Generate .js code
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List(new GenBCode) // Generate JVM bytecode
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)
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var runId = 1

‎src/dotty/tools/dotc/transform/ElimStaticThis.scala

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@ import dotty.tools.dotc.core.SymDenotations.SymDenotation
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import TreeTransforms.{MiniPhaseTransform, TransformerInfo}
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import dotty.tools.dotc.core.Types.{ThisType, TermRef}
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/** Replace This references to module classes in static methods by global identifiers to the
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/** Replace This references to module classes in static methods by global identifiers to the
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* corresponding modules.
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*/
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class ElimStaticThis extends MiniPhaseTransform {

‎src/dotty/tools/dotc/transform/GetClass.scala

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -20,7 +20,8 @@ class GetClass extends MiniPhaseTransform {
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override def phaseName: String = "getClass"
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override def runsAfter: Set[Class[_ <: Phase]] = Set(classOf[Erasure])
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// getClass transformation should be applied to specialized methods
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override def runsAfter: Set[Class[_ <: Phase]] = Set(classOf[Erasure], classOf[FunctionalInterfaces])
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override def transformApply(tree: Apply)(implicit ctx: Context, info: TransformerInfo): Tree = {
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import ast.Trees._

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