Backport "Add support for xsbti.compile.CompileProgress" to LTS (#20754)

Backports #18739 to the LTS branch.

PR submitted by the release tooling.
[skip ci]

compiler/src/dotty/tools/dotc/Run.scala

@@ -12,7 +12,9 @@ import typer.Typer
 import typer.ImportInfo.withRootImports
 import Decorators._
 import io.AbstractFile
-import Phases.unfusedPhases
+import Phases.{unfusedPhases, Phase}
+
+import sbt.interfaces.ProgressCallback
 
 import util._
 import reporting.{Suppression, Action, Profile, ActiveProfile, NoProfile}
@@ -32,6 +34,10 @@ import scala.collection.mutable
 import scala.util.control.NonFatal
 import scala.io.Codec
 
+import Run.Progress
+import scala.compiletime.uninitialized
+import dotty.tools.dotc.transform.MegaPhase
+
 /** A compiler run. Exports various methods to compile source files */
 class Run(comp: Compiler, ictx: Context) extends ImplicitRunInfo with ConstraintRunInfo {
 
@@ -155,14 +161,75 @@ class Run(comp: Compiler, ictx: Context) extends ImplicitRunInfo with Constraint
   }
 
   /** The source files of all late entered symbols, as a set */
-  private var lateFiles = mutable.Set[AbstractFile]()
+  private val lateFiles = mutable.Set[AbstractFile]()
 
   /** A cache for static references to packages and classes */
   val staticRefs = util.EqHashMap[Name, Denotation](initialCapacity = 1024)
 
   /** Actions that need to be performed at the end of the current compilation run */
   private var finalizeActions = mutable.ListBuffer[() => Unit]()
 
+  private var _progress: Progress | Null = null // Set if progress reporting is enabled
+
+  private inline def trackProgress(using Context)(inline op: Context ?=> Progress => Unit): Unit =
+    foldProgress(())(op)
+
+  private inline def foldProgress[T](using Context)(inline default: T)(inline op: Context ?=> Progress => T): T =
+    val local = _progress
+    if local != null then
+      op(using ctx)(local)
+    else
+      default
+
+  def didEnterUnit(unit: CompilationUnit)(using Context): Boolean =
+    foldProgress(true /* should progress by default */)(_.tryEnterUnit(unit))
+
+  def canProgress()(using Context): Boolean =
+    foldProgress(true /* not cancelled by default */)(p => !p.checkCancellation())
+
+  def doAdvanceUnit()(using Context): Unit =
+    trackProgress: progress =>
+      progress.currentUnitCount += 1 // trace that we completed a unit in the current (sub)phase
+      progress.refreshProgress()
+
+  def doAdvanceLate()(using Context): Unit =
+    trackProgress: progress =>
+      progress.currentLateUnitCount += 1 // trace that we completed a late compilation
+      progress.refreshProgress()
+
+  private def doEnterPhase(currentPhase: Phase)(using Context): Unit =
+    trackProgress: progress =>
+      progress.enterPhase(currentPhase)
+
+  /** interrupt the thread and set cancellation state */
+  private def cancelInterrupted(): Unit =
+    try
+      trackProgress(_.cancel())
+    finally
+      Thread.currentThread().nn.interrupt()
+
+  private def doAdvancePhase(currentPhase: Phase, wasRan: Boolean)(using Context): Unit =
+    trackProgress: progress =>
+      progress.currentUnitCount = 0 // reset unit count in current (sub)phase
+      progress.currentCompletedSubtraversalCount = 0 // reset subphase index to initial
+      progress.seenPhaseCount += 1 // trace that we've seen a (sub)phase
+      if wasRan then
+        // add an extra traversal now that we completed a (sub)phase
+        progress.completedTraversalCount += 1
+      else
+        // no subphases were ran, remove traversals from expected total
+        progress.totalTraversals -= currentPhase.traversals
+
+  private def tryAdvanceSubPhase()(using Context): Unit =
+    trackProgress: progress =>
+      if progress.canAdvanceSubPhase then
+        progress.currentUnitCount = 0 // reset unit count in current (sub)phase
+        progress.seenPhaseCount += 1 // trace that we've seen a (sub)phase
+        progress.completedTraversalCount += 1 // add an extra traversal now that we completed a (sub)phase
+        progress.currentCompletedSubtraversalCount += 1 // record that we've seen a subphase
+        if !progress.isCancelled() then
+          progress.tickSubphase()
+
   /** Will be set to true if any of the compiled compilation units contains
    *  a pureFunctions language import.
    */
@@ -233,17 +300,20 @@ class Run(comp: Compiler, ictx: Context) extends ImplicitRunInfo with Constraint
     if ctx.settings.YnoDoubleBindings.value then
       ctx.base.checkNoDoubleBindings = true
 
-    def runPhases(using Context) = {
+    def runPhases(allPhases: Array[Phase])(using Context) = {
       var lastPrintedTree: PrintedTree = NoPrintedTree
       val profiler = ctx.profiler
       var phasesWereAdjusted = false
 
-      for (phase <- ctx.base.allPhases)
-        if (phase.isRunnable)
+      for phase <- allPhases do
+        doEnterPhase(phase)
+        val phaseWillRun = phase.isRunnable
+        if phaseWillRun then
           Stats.trackTime(s"phase time ms/$phase") {
             val start = System.currentTimeMillis
             val profileBefore = profiler.beforePhase(phase)
-            units = phase.runOn(units)
+            try units = phase.runOn(units)
+            catch case _: InterruptedException => cancelInterrupted()
             profiler.afterPhase(phase, profileBefore)
             if (ctx.settings.Xprint.value.containsPhase(phase))
               for (unit <- units)
@@ -260,18 +330,25 @@ class Run(comp: Compiler, ictx: Context) extends ImplicitRunInfo with Constraint
             if !Feature.ccEnabledSomewhere then
               ctx.base.unlinkPhaseAsDenotTransformer(Phases.checkCapturesPhase.prev)
               ctx.base.unlinkPhaseAsDenotTransformer(Phases.checkCapturesPhase)
-
+            end if
+          end if
+        end if
+        doAdvancePhase(phase, wasRan = phaseWillRun)
+      end for
       profiler.finished()
     }
 
     val runCtx = ctx.fresh
     runCtx.setProfiler(Profiler())
     unfusedPhases.foreach(_.initContext(runCtx))
-    runPhases(using runCtx)
+    val fusedPhases = runCtx.base.allPhases
+    runCtx.withProgressCallback: cb =>
+      _progress = Progress(cb, this, fusedPhases.map(_.traversals).sum)
+    runPhases(allPhases = fusedPhases)(using runCtx)
     if (!ctx.reporter.hasErrors)
       Rewrites.writeBack()
     suppressions.runFinished(hasErrors = ctx.reporter.hasErrors)
-    while (finalizeActions.nonEmpty) {
+    while (finalizeActions.nonEmpty && canProgress()) {
       val action = finalizeActions.remove(0)
       action()
     }
@@ -293,10 +370,9 @@ class Run(comp: Compiler, ictx: Context) extends ImplicitRunInfo with Constraint
         .withRootImports
 
       def process()(using Context) =
-        ctx.typer.lateEnterUnit(doTypeCheck =>
-          if typeCheck then
-            if compiling then finalizeActions += doTypeCheck
-            else doTypeCheck()
+        ctx.typer.lateEnterUnit(typeCheck)(doTypeCheck =>
+          if compiling then finalizeActions += doTypeCheck
+          else doTypeCheck()
         )
 
       process()(using unitCtx)
@@ -399,7 +475,129 @@ class Run(comp: Compiler, ictx: Context) extends ImplicitRunInfo with Constraint
 }
 
 object Run {
+
+  case class SubPhase(val name: String):
+    override def toString: String = name
+
+  class SubPhases(val phase: Phase):
+    require(phase.exists)
+
+    private def baseName: String = phase match
+      case phase: MegaPhase => phase.shortPhaseName
+      case phase => phase.phaseName
+
+    val all = IArray.from(phase.subPhases.map(sub => s"$baseName[$sub]"))
+
+    def next(using Context): Option[SubPhases] =
+      val next0 = phase.megaPhase.next.megaPhase
+      if next0.exists then Some(SubPhases(next0))
+      else None
+
+    def size: Int = all.size
+
+    def subPhase(index: Int) =
+      if index < all.size then all(index)
+      else baseName
+
+
+  private class Progress(cb: ProgressCallback, private val run: Run, val initialTraversals: Int):
+    export cb.{cancel, isCancelled}
+
+    var totalTraversals: Int = initialTraversals  // track how many phases we expect to run
+    var currentUnitCount: Int = 0 // current unit count in the current (sub)phase
+    var currentLateUnitCount: Int = 0 // current late unit count
+    var completedTraversalCount: Int = 0 // completed traversals over all files
+    var currentCompletedSubtraversalCount: Int = 0 // completed subphases in the current phase
+    var seenPhaseCount: Int = 0 // how many phases we've seen so far
+
+    private var currPhase: Phase = uninitialized  // initialized by enterPhase
+    private var subPhases: SubPhases = uninitialized  // initialized by enterPhase
+    private var currPhaseName: String = uninitialized // initialized by enterPhase
+    private var nextPhaseName: String = uninitialized // initialized by enterPhase
+
+    /** Enter into a new real phase, setting the current and next (sub)phases */
+    def enterPhase(newPhase: Phase)(using Context): Unit =
+      if newPhase ne currPhase then
+        currPhase = newPhase
+        subPhases = SubPhases(newPhase)
+        tickSubphase()
+
+    def canAdvanceSubPhase: Boolean =
+      currentCompletedSubtraversalCount + 1 < subPhases.size
+
+    /** Compute the current (sub)phase name and next (sub)phase name */
+    def tickSubphase()(using Context): Unit =
+      val index = currentCompletedSubtraversalCount
+      val s = subPhases
+      currPhaseName = s.subPhase(index)
+      nextPhaseName =
+        if index + 1 < s.all.size then s.subPhase(index + 1)
+        else s.next match
+          case None => "<end>"
+          case Some(next0) => next0.subPhase(0)
+      if seenPhaseCount > 0 then
+        refreshProgress()
+
+
+    /** Counts the number of completed full traversals over files, plus the number of units in the current phase */
+    private def currentProgress(): Int =
+      completedTraversalCount * work() + currentUnitCount + currentLateUnitCount
+
+    /**Total progress is computed as the sum of
+     * - the number of traversals we expect to make over all files
+     * - the number of late compilations
+     */
+    private def totalProgress(): Int =
+      totalTraversals * work() + run.lateFiles.size
+
+    private def work(): Int = run.files.size
+
+    private def requireInitialized(): Unit =
+      require((currPhase: Phase | Null) != null, "enterPhase was not called")
+
+    def checkCancellation(): Boolean =
+      if Thread.interrupted() then cancel()
+      isCancelled()
+
+    /** trace that we are beginning a unit in the current (sub)phase, unless cancelled */
+    def tryEnterUnit(unit: CompilationUnit): Boolean =
+      if checkCancellation() then false
+      else
+        requireInitialized()
+        cb.informUnitStarting(currPhaseName, unit)
+        true
+
+    /** trace the current progress out of the total, in the current (sub)phase, reporting the next (sub)phase */
+    def refreshProgress()(using Context): Unit =
+      requireInitialized()
+      val total = totalProgress()
+      if total > 0 && !cb.progress(currentProgress(), total, currPhaseName, nextPhaseName) then
+        cancel()
+
   extension (run: Run | Null)
+
+    /** record that the current phase has begun for the compilation unit of the current Context */
+    def enterUnit(unit: CompilationUnit)(using Context): Boolean =
+      if run != null then run.didEnterUnit(unit)
+      else true // don't check cancellation if we're not tracking progress
+
+    /** check progress cancellation, true if not cancelled */
+    def enterRegion()(using Context): Boolean =
+      if run != null then run.canProgress()
+      else true // don't check cancellation if we're not tracking progress
+
+    /** advance the unit count and record progress in the current phase */
+    def advanceUnit()(using Context): Unit =
+      if run != null then run.doAdvanceUnit()
+
+    /** if there exists another subphase, switch to it and record progress */
+    def enterNextSubphase()(using Context): Unit =
+      if run != null then run.tryAdvanceSubPhase()
+
+    /** advance the late count and record progress in the current phase */
+    def advanceLate()(using Context): Unit =
+      if run != null then run.doAdvanceLate()
+
     def enrichedErrorMessage: Boolean = if run == null then false else run.myEnrichedErrorMessage
     def enrichErrorMessage(errorMessage: String)(using Context): String =
       if run == null then

compiler/src/dotty/tools/dotc/core/Contexts.scala

@@ -34,7 +34,7 @@ import scala.annotation.internal.sharable
 
 import DenotTransformers.DenotTransformer
 import dotty.tools.dotc.profile.Profiler
-import dotty.tools.dotc.sbt.interfaces.IncrementalCallback
+import dotty.tools.dotc.sbt.interfaces.{IncrementalCallback, ProgressCallback}
 import util.Property.Key
 import util.Store
 import plugins._
@@ -53,8 +53,9 @@ object Contexts {
   private val (notNullInfosLoc,      store8) = store7.newLocation[List[NotNullInfo]]()
   private val (importInfoLoc,        store9) = store8.newLocation[ImportInfo | Null]()
   private val (typeAssignerLoc,     store10) = store9.newLocation[TypeAssigner](TypeAssigner)
+  private val (progressCallbackLoc, store11) = store10.newLocation[ProgressCallback | Null]()
 
-  private val initialStore = store10
+  private val initialStore = store11
 
   /** The current context */
   inline def ctx(using ctx: Context): Context = ctx
@@ -177,6 +178,14 @@ object Contexts {
       val local = incCallback
       local != null && local.enabled || forceRun
 
+    /** The Zinc compile progress callback implementation if we are run from Zinc, null otherwise */
+    def progressCallback: ProgressCallback | Null = store(progressCallbackLoc)
+
+    /** Run `op` if there exists a Zinc progress callback */
+    inline def withProgressCallback(inline op: ProgressCallback => Unit): Unit =
+      val local = progressCallback
+      if local != null then op(local)
+
     /** The current plain printer */
     def printerFn: Context => Printer = store(printerFnLoc)
 
@@ -675,6 +684,7 @@ object Contexts {
 
     def setCompilerCallback(callback: CompilerCallback): this.type = updateStore(compilerCallbackLoc, callback)
     def setIncCallback(callback: IncrementalCallback): this.type = updateStore(incCallbackLoc, callback)
+    def setProgressCallback(callback: ProgressCallback): this.type = updateStore(progressCallbackLoc, callback)
     def setPrinterFn(printer: Context => Printer): this.type = updateStore(printerFnLoc, printer)
     def setSettings(settingsState: SettingsState): this.type = updateStore(settingsStateLoc, settingsState)
     def setRun(run: Run | Null): this.type = updateStore(runLoc, run)