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package dotty.tools
package dotc
import core._
import Contexts._
import Periods._
import Symbols._
import Types._
import Scopes._
import typer.{FrontEnd, ImportInfo, RefChecks, Typer}
import reporting.{ConsoleReporter, Reporter}
import Phases.Phase
import transform._
import util.FreshNameCreator
import core.DenotTransformers.DenotTransformer
import core.Denotations.SingleDenotation
import dotty.tools.backend.jvm.{CollectSuperCalls, GenBCode, LabelDefs}
import dotty.tools.dotc.transform.localopt.StringInterpolatorOpt
/** The central class of the dotc compiler. The job of a compiler is to create
* runs, which process given `phases` in a given `rootContext`.
*/
class Compiler {
/** Meta-ordering constraint:
*
* DenotTransformers that change the signature of their denotation's info must go
* after erasure. The reason is that denotations are permanently referred to by
* TermRefs which contain a signature. If the signature of a symbol would change,
* all refs to it would become outdated - they could not be dereferenced in the
* new phase.
*
* After erasure, signature changing denot-transformers are OK because erasure
* will make sure that only term refs with fixed SymDenotations survive beyond it. This
* is possible because:
*
* - splitter has run, so every ident or select refers to a unique symbol
* - after erasure, asSeenFrom is the identity, so every reference has a
* plain SymDenotation, as opposed to a UniqueRefDenotation.
*/
def phases: List[List[Phase]] =
frontendPhases ::: picklerPhases ::: transformPhases ::: backendPhases
/** Phases dealing with the frontend up to trees ready for TASTY pickling */
protected def frontendPhases: List[List[Phase]] =
List(new FrontEnd) :: // Compiler frontend: scanner, parser, namer, typer
List(new sbt.ExtractDependencies) :: // Sends information on classes' dependencies to sbt via callbacks
List(new PostTyper) :: // Additional checks and cleanups after type checking
List(new sbt.ExtractAPI) :: // Sends a representation of the API of classes to sbt via callbacks
Nil
/** Phases dealing with TASTY tree pickling and unpickling */
protected def picklerPhases: List[List[Phase]] =
List(new Pickler) :: // Generate TASTY info
List(new ReifyQuotes) :: // Turn quoted trees into explicit run-time data structures
Nil
/** Phases dealing with the transformation from pickled trees to backend trees */
protected def transformPhases: List[List[Phase]] =
List(new FirstTransform, // Some transformations to put trees into a canonical form
new CheckReentrant, // Internal use only: Check that compiled program has no data races involving global vars
new ElimPackagePrefixes, // Eliminate references to package prefixes in Select nodes
new CookComments) :: // Cook the comments: expand variables, doc, etc.
List(new CheckStatic, // Check restrictions that apply to @static members
new ElimRepeated, // Rewrite vararg parameters and arguments
new ExpandSAMs, // Expand single abstract method closures to anonymous classes
new ProtectedAccessors, // Add accessors for protected members
new ExtensionMethods, // Expand methods of value classes with extension methods
new ShortcutImplicits, // Allow implicit functions without creating closures
new TailRec, // Rewrite tail recursion to loops
new ByNameClosures, // Expand arguments to by-name parameters to closures
new LiftTry, // Put try expressions that might execute on non-empty stacks into their own methods
new HoistSuperArgs, // Hoist complex arguments of supercalls to enclosing scope
new ClassOf, // Expand `Predef.classOf` calls.
new RefChecks) :: // Various checks mostly related to abstract members and overriding
List(new TryCatchPatterns, // Compile cases in try/catch
new PatternMatcher, // Compile pattern matches
new ExplicitOuter, // Add accessors to outer classes from nested ones.
new ExplicitSelf, // Make references to non-trivial self types explicit as casts
new StringInterpolatorOpt, // Optimizes raw and s string interpolators by rewriting them to string concatentations
new CrossCastAnd, // Normalize selections involving intersection types.
new Splitter) :: // Expand selections involving union types into conditionals
List(new PruneErasedDefs, // Drop erased definitions from scopes and simplify erased expressions
new VCInlineMethods, // Inlines calls to value class methods
new SeqLiterals, // Express vararg arguments as arrays
new InterceptedMethods, // Special handling of `==`, `|=`, `getClass` methods
new Getters, // Replace non-private vals and vars with getter defs (fields are added later)
new ElimByName, // Expand by-name parameter references
new CollectNullableFields, // Collect fields that can be nulled out after use in lazy initialization
new ElimOuterSelect, // Expand outer selections
new AugmentScala2Traits, // Expand traits defined in Scala 2.x to simulate old-style rewritings
new ResolveSuper, // Implement super accessors and add forwarders to trait methods
new PrimitiveForwarders, // Add forwarders to trait methods that have a mismatch between generic and primitives
new FunctionXXLForwarders, // Add forwarders for FunctionXXL apply method
new ArrayConstructors) :: // Intercept creation of (non-generic) arrays and intrinsify.
List(new Erasure) :: // Rewrite types to JVM model, erasing all type parameters, abstract types and refinements.
List(new ElimErasedValueType, // Expand erased value types to their underlying implmementation types
new VCElideAllocations, // Peep-hole optimization to eliminate unnecessary value class allocations
new Mixin, // Expand trait fields and trait initializers
new LazyVals, // Expand lazy vals
new Memoize, // Add private fields to getters and setters
new NonLocalReturns, // Expand non-local returns
new CapturedVars) :: // Represent vars captured by closures as heap objects
List(new Constructors, // Collect initialization code in primary constructors
// Note: constructors changes decls in transformTemplate, no InfoTransformers should be added after it
new FunctionalInterfaces, // Rewrites closures to implement @specialized types of Functions.
new GetClass) :: // Rewrites getClass calls on primitive types.
List(new LinkScala2Impls, // Redirect calls to trait methods defined by Scala 2.x, so that they now go to their implementations
new LambdaLift, // Lifts out nested functions to class scope, storing free variables in environments
// Note: in this mini-phase block scopes are incorrect. No phases that rely on scopes should be here
new ElimStaticThis) :: // Replace `this` references to static objects by global identifiers
List(new Flatten, // Lift all inner classes to package scope
new RenameLifted, // Renames lifted classes to local numbering scheme
new TransformWildcards, // Replace wildcards with default values
new MoveStatics, // Move static methods from companion to the class itself
new ExpandPrivate, // Widen private definitions accessed from nested classes
new RestoreScopes, // Repair scopes rendered invalid by moving definitions in prior phases of the group
new SelectStatic, // get rid of selects that would be compiled into GetStatic
new CollectEntryPoints, // Find classes with main methods
new CollectSuperCalls, // Find classes that are called with super
new LabelDefs) :: // Converts calls to labels to jumps
Nil
/** Generate the output of the compilation */
protected def backendPhases: List[List[Phase]] =
List(new GenBCode) :: // Generate JVM bytecode
Nil
var runId = 1
def nextRunId = {
runId += 1; runId
}
def reset()(implicit ctx: Context): Unit = {
ctx.base.reset()
if (ctx.run != null) ctx.run.reset()
}
def newRun(implicit ctx: Context): Run = {
reset()
new Run(this, ctx)
}
}