Merge pull request #9866 from dotty-staging/optimize-backend

Some Optimizations in Backend

Author: odersky

compiler/src/dotty/tools/backend/jvm/BCodeBodyBuilder.scala

@@ -39,7 +39,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
   import coreBTypes._
   import BCodeBodyBuilder._
 
-  private val primitives = new DottyPrimitives(ctx)
+  protected val primitives: DottyPrimitives
 
   /*
    * Functionality to build the body of ASM MethodNode, except for `synchronized` and `try` expressions.
@@ -1021,9 +1021,15 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
       }
     }
 
-    def genLoadArguments(args: List[Tree], btpes: List[BType]): Unit = {
-      (args zip btpes) foreach { case (arg, btpe) => genLoad(arg, btpe) }
-    }
+    def genLoadArguments(args: List[Tree], btpes: List[BType]): Unit =
+      args match
+        case arg :: args1 =>
+          btpes match
+            case btpe :: btpes1 =>
+              genLoad(arg, btpe)
+              genLoadArguments(args1, btpes1)
+            case _ =>
+        case _ =>
 
     def genLoadModule(tree: Tree): BType = {
       val module = (

compiler/src/dotty/tools/backend/jvm/BCodeIdiomatic.scala

@@ -35,10 +35,10 @@ trait BCodeIdiomatic {
   lazy val majorVersion: Int = (classfileVersion & 0xFF)
   lazy val emitStackMapFrame = (majorVersion >= 50)
 
-  val extraProc: Int = GenBCodeOps.mkFlags(
-    asm.ClassWriter.COMPUTE_MAXS,
-    if (emitStackMapFrame) asm.ClassWriter.COMPUTE_FRAMES else 0
-  )
+  val extraProc: Int =
+    import GenBCodeOps.addFlagIf
+    asm.ClassWriter.COMPUTE_MAXS
+      .addFlagIf(emitStackMapFrame, asm.ClassWriter.COMPUTE_FRAMES)
 
   lazy val JavaStringBuilderClassName = jlStringBuilderRef.internalName
 

compiler/src/dotty/tools/backend/jvm/BCodeSkelBuilder.scala

@@ -535,7 +535,7 @@ trait BCodeSkelBuilder extends BCodeHelpers {
     }
     def lineNumber(tree: Tree): Unit = {
       if (!emitLines || !tree.span.exists) return;
-      val nr = ctx.source.atSpan(tree.span).line + 1
+      val nr = ctx.source.offsetToLine(tree.span.point) + 1
       if (nr != lastEmittedLineNr) {
         lastEmittedLineNr = nr
         lastInsn match {
@@ -690,12 +690,12 @@ trait BCodeSkelBuilder extends BCodeHelpers {
 
       val isNative         = methSymbol.hasAnnotation(NativeAttr)
       val isAbstractMethod = (methSymbol.is(Deferred) || (methSymbol.owner.isInterface && ((methSymbol.is(Deferred))  || methSymbol.isClassConstructor)))
-      val flags = GenBCodeOps.mkFlags(
-        javaFlags(methSymbol),
-        if (isAbstractMethod)        asm.Opcodes.ACC_ABSTRACT   else 0,
-        if (false /*methSymbol.isStrictFP*/)   asm.Opcodes.ACC_STRICT     else 0,
-        if (isNative)                asm.Opcodes.ACC_NATIVE     else 0  // native methods of objects are generated in mirror classes
-      )
+      val flags =
+        import GenBCodeOps.addFlagIf
+        javaFlags(methSymbol)
+          .addFlagIf(isAbstractMethod, asm.Opcodes.ACC_ABSTRACT)
+          .addFlagIf(false /*methSymbol.isStrictFP*/, asm.Opcodes.ACC_STRICT)
+          .addFlagIf(isNative, asm.Opcodes.ACC_NATIVE) // native methods of objects are generated in mirror classes
 
       // TODO needed? for(ann <- m.symbol.annotations) { ann.symbol.initialize }
       initJMethod(flags, params.map(p => p.symbol.annotations))

compiler/src/dotty/tools/backend/jvm/BTypes.scala

@@ -649,14 +649,13 @@ abstract class BTypes {
 
     def innerClassAttributeEntry: Option[InnerClassEntry] = info.nestedInfo map {
       case NestedInfo(_, outerName, innerName, isStaticNestedClass) =>
+        import GenBCodeOps.addFlagIf
         InnerClassEntry(
           internalName,
           outerName.orNull,
           innerName.orNull,
-          GenBCodeOps.mkFlags(
-            info.flags,
-            if (isStaticNestedClass) asm.Opcodes.ACC_STATIC else 0
-          ) & ClassBType.INNER_CLASSES_FLAGS
+          info.flags.addFlagIf(isStaticNestedClass, asm.Opcodes.ACC_STATIC)
+            & ClassBType.INNER_CLASSES_FLAGS
         )
     }
 

compiler/src/dotty/tools/backend/jvm/BTypesFromSymbols.scala

@@ -304,39 +304,36 @@ class BTypesFromSymbols[I <: DottyBackendInterface](val int: I) extends BTypes {
     val finalFlag = sym.is(Final) && !toDenot(sym).isClassConstructor && !sym.is(Mutable) && !sym.enclosingClass.is(Trait)
 
     import asm.Opcodes._
-    GenBCodeOps.mkFlags(
-      if (privateFlag) ACC_PRIVATE else ACC_PUBLIC,
-      if (sym.is(Deferred) || sym.isOneOf(AbstractOrTrait)) ACC_ABSTRACT else 0,
-      if (sym.isInterface) ACC_INTERFACE else 0,
-
-      if (finalFlag &&
+    import GenBCodeOps.addFlagIf
+    0 .addFlagIf(privateFlag, ACC_PRIVATE)
+      .addFlagIf(!privateFlag, ACC_PUBLIC)
+      .addFlagIf(sym.is(Deferred) || sym.isOneOf(AbstractOrTrait), ACC_ABSTRACT)
+      .addFlagIf(sym.isInterface, ACC_INTERFACE)
+      .addFlagIf(finalFlag
         // Primitives are "abstract final" to prohibit instantiation
         // without having to provide any implementations, but that is an
         // illegal combination of modifiers at the bytecode level so
         // suppress final if abstract if present.
-        !sym.isOneOf(AbstractOrTrait) &&
+        && !sym.isOneOf(AbstractOrTrait)
         //  Mixin forwarders are bridges and can be final, but final bridges confuse some frameworks
-        !sym.is(Bridge))
-        ACC_FINAL else 0,
-
-      if (sym.isStaticMember) ACC_STATIC else 0,
-      if (sym.is(Bridge)) ACC_BRIDGE | ACC_SYNTHETIC else 0,
-      if (sym.is(Artifact)) ACC_SYNTHETIC else 0,
-      if (sym.isClass && !sym.isInterface) ACC_SUPER else 0,
-      if (sym.isAllOf(JavaEnumTrait)) ACC_ENUM else 0,
-      if (sym.is(JavaVarargs)) ACC_VARARGS else 0,
-      if (sym.is(Synchronized)) ACC_SYNCHRONIZED else 0,
-      if (sym.isDeprecated) ACC_DEPRECATED else 0,
-      if (sym.is(Enum)) ACC_ENUM else 0
-    )
+        && !sym.is(Bridge), ACC_FINAL)
+      .addFlagIf(sym.isStaticMember, ACC_STATIC)
+      .addFlagIf(sym.is(Bridge), ACC_BRIDGE | ACC_SYNTHETIC)
+      .addFlagIf(sym.is(Artifact), ACC_SYNTHETIC)
+      .addFlagIf(sym.isClass && !sym.isInterface, ACC_SUPER)
+      .addFlagIf(sym.isAllOf(JavaEnumTrait), ACC_ENUM)
+      .addFlagIf(sym.is(JavaVarargs), ACC_VARARGS)
+      .addFlagIf(sym.is(Synchronized), ACC_SYNCHRONIZED)
+      .addFlagIf(sym.isDeprecated, ACC_DEPRECATED)
+      .addFlagIf(sym.is(Enum), ACC_ENUM)
   }
 
   def javaFieldFlags(sym: Symbol) = {
     import asm.Opcodes._
-    javaFlags(sym) | GenBCodeOps.mkFlags(
-      if (sym.hasAnnotation(TransientAttr)) ACC_TRANSIENT else 0,
-      if (sym.hasAnnotation(VolatileAttr)) ACC_VOLATILE else 0,
-      if (sym.is(Mutable)) 0 else ACC_FINAL
-    )
+    import GenBCodeOps.addFlagIf
+    javaFlags(sym)
+      .addFlagIf(sym.hasAnnotation(TransientAttr), ACC_TRANSIENT)
+      .addFlagIf(sym.hasAnnotation(VolatileAttr), ACC_VOLATILE)
+      .addFlagIf(!sym.is(Mutable), ACC_FINAL)
   }
 }

compiler/src/dotty/tools/backend/jvm/GenBCode.scala

@@ -50,9 +50,13 @@ class GenBCode extends Phase {
     myOutput
   }
 
+  private var myPrimitives: DottyPrimitives = null
+
   def run(using Context): Unit =
-    GenBCodePipeline(
-      DottyBackendInterface(outputDir, superCallsMap)
+    if myPrimitives == null then myPrimitives = new DottyPrimitives(ctx)
+    new GenBCodePipeline(
+      DottyBackendInterface(outputDir, superCallsMap),
+      myPrimitives
     ).run(ctx.compilationUnit.tpdTree)
 
 
@@ -74,7 +78,7 @@ object GenBCode {
   val name: String = "genBCode"
 }
 
-class GenBCodePipeline(val int: DottyBackendInterface)(using Context) extends BCodeSyncAndTry {
+class GenBCodePipeline(val int: DottyBackendInterface, val primitives: DottyPrimitives)(using Context) extends BCodeSyncAndTry {
   import DottyBackendInterface.symExtensions
 
   private var tree: Tree = _

compiler/src/dotty/tools/backend/jvm/GenBCodeOps.scala

@@ -7,7 +7,8 @@ import scala.tools.asm
 object GenBCodeOps extends GenBCodeOps
 
 class GenBCodeOps {
-  def mkFlags(args: Int*) = args.foldLeft(0)(_ | _)
+  extension (flags: Int)
+    def addFlagIf(cond: Boolean, flag: Int): Int = if cond then flags | flag else flags
 
   final val PublicStatic      = asm.Opcodes.ACC_PUBLIC | asm.Opcodes.ACC_STATIC
   final val PublicStaticFinal = asm.Opcodes.ACC_PUBLIC | asm.Opcodes.ACC_STATIC | asm.Opcodes.ACC_FINAL

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -596,9 +596,9 @@ object desugar {
           (ordinalMethLit(ordinal) :: enumLabelLit(className.toString) :: Nil, scaffolding)
         else (Nil, Nil)
       def copyMeths = {
-        val hasRepeatedParam = constrVparamss.exists(_.exists {
+        val hasRepeatedParam = constrVparamss.nestedExists {
           case ValDef(_, tpt, _) => isRepeated(tpt)
-        })
+        }
         if (mods.is(Abstract) || hasRepeatedParam) Nil  // cannot have default arguments for repeated parameters, hence copy method is not issued
         else {
           def copyDefault(vparam: ValDef) =

compiler/src/dotty/tools/dotc/ast/DesugarEnums.scala

@@ -297,7 +297,7 @@ object DesugarEnums {
       case parent => parent.isType && typeHasRef(parent)
     }
 
-    vparamss.exists(_.exists(valDefHasRef)) || parents.exists(parentHasRef)
+    vparamss.nestedExists(valDefHasRef) || parents.exists(parentHasRef)
   }
 
   /** A pair consisting of

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

@@ -195,12 +195,16 @@ object Decorators {
   }
 
   extension [T, U](xss: List[List[T]])
-    def nestedMap(f: T => U): List[List[U]] =
-      xss.map(_.map(f))
+    def nestedMap(f: T => U): List[List[U]] = xss match
+      case xs :: xss1 => xs.map(f) :: xss1.nestedMap(f)
+      case nil => Nil
     def nestedMapConserve(f: T => U): List[List[U]] =
       xss.mapconserve(_.mapconserve(f))
     def nestedZipWithConserve(yss: List[List[U]])(f: (T, U) => T): List[List[T]] =
       xss.zipWithConserve(yss)((xs, ys) => xs.zipWithConserve(ys)(f))
+    def nestedExists(p: T => Boolean): Boolean = xss match
+      case xs :: xss1 => xs.exists(p) || xss1.nestedExists(p)
+      case nil => false
   end extension
 
   extension (text: Text)

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

@@ -899,7 +899,7 @@ object SymDenotations {
       else if is(NoDefaultParams) then false
       else
         val result =
-          rawParamss.exists(_.exists(_.is(HasDefault)))
+          rawParamss.nestedExists(_.is(HasDefault))
           || allOverriddenSymbols.exists(_.hasDefaultParams)
         setFlag(if result then HasDefaultParams else NoDefaultParams)
         result

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -3847,7 +3847,7 @@ object Parsers {
         val problem = tree match
           case tree: MemberDef if !(tree.mods.flags & ModifierFlags).isEmpty =>
             i"refinement cannot be ${(tree.mods.flags & ModifierFlags).flagStrings().mkString("`", "`, `", "`")}"
-          case tree: DefDef if tree.vparamss.exists(_.exists(!_.rhs.isEmpty)) =>
+          case tree: DefDef if tree.vparamss.nestedExists(!_.rhs.isEmpty) =>
             i"refinement cannot have default arguments"
           case tree: ValOrDefDef =>
             if tree.rhs.isEmpty then ""

compiler/src/dotty/tools/dotc/transform/ElimRepeated.scala

@@ -237,7 +237,7 @@ class ElimRepeated extends MiniPhase with InfoTransformer { thisPhase =>
 
   /** Is there a repeated parameter in some parameter list? */
   private def hasRepeatedParams(sym: Symbol)(using Context): Boolean =
-    sym.info.paramInfoss.flatten.exists(_.isRepeatedParam)
+    sym.info.paramInfoss.nestedExists(_.isRepeatedParam)
 
   /** Is this the type of a method that has a repeated parameter type as
    *  its last parameter in the last parameter list?

compiler/src/dotty/tools/dotc/util/SourcePosition.scala

@@ -25,7 +25,7 @@ extends SrcPos, interfaces.SourcePosition, Showable {
 
   def point: Int = span.point
 
-  def line: Int = if (source.content().length != 0) source.offsetToLine(point) else -1
+  def line: Int = if (source.length != 0) source.offsetToLine(point) else -1
 
   /** Extracts the lines from the underlying source file as `Array[Char]`*/
   def linesSlice: Array[Char] =