diff options
Diffstat (limited to 'src/compiler/scala/tools/nsc/typechecker/Macros.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Macros.scala | 115 |
1 files changed, 66 insertions, 49 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Macros.scala b/src/compiler/scala/tools/nsc/typechecker/Macros.scala index 02fb70f3e5..27920dbd74 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Macros.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Macros.scala @@ -29,7 +29,7 @@ import Fingerprint._ * Then fooBar needs to point to a static method of the following form: * * def fooBar[T: c.WeakTypeTag] // type tag annotation is optional - * (c: scala.reflect.macros.Context) + * (c: scala.reflect.macros.BlackboxContext) * (xs: c.Expr[List[T]]) * : c.Expr[T] = { * ... @@ -67,7 +67,7 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { * * This solution is very simple, but unfortunately it's also lacking. If we use it, then * signatures of macro defs become transitively dependent on scala-reflect.jar - * (because they refer to macro impls, and macro impls refer to scala.reflect.macros.Context defined in scala-reflect.jar). + * (because they refer to macro impls, and macro impls refer to scala.reflect.macros.BlackboxContext/WhiteboxContext defined in scala-reflect.jar). * More details can be found in comments to https://issues.scala-lang.org/browse/SI-5940. * * Therefore we have to avoid putting macro impls into binding pickles and come up with our own serialization format. @@ -81,40 +81,42 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { * and various accounting information necessary when composing an argument list for the reflective invocation. */ case class MacroImplBinding( - // Is this macro impl a bundle (a trait extending Macro) or a vanilla def? - val isBundle: Boolean, - // Java class name of the class that contains the macro implementation - // is used to load the corresponding object with Java reflection - className: String, - // method name of the macro implementation - // `className` and `methName` are all we need to reflectively invoke a macro implementation - // because macro implementations cannot be overloaded - methName: String, - // flattens the macro impl's parameter lists having symbols replaced with their fingerprints - // currently fingerprints are calculated solely from types of the symbols: - // * c.Expr[T] => LiftedTyped - // * c.Tree => LiftedUntyped - // * c.WeakTypeTag[T] => Tagged(index of the type parameter corresponding to that type tag) - // * everything else (e.g. scala.reflect.macros.Context) => Other - // f.ex. for: def impl[T: WeakTypeTag, U, V: WeakTypeTag](c: Context)(x: c.Expr[T], y: c.Tree): (U, V) = ??? - // `signature` will be equal to List(List(Other), List(LiftedTyped, LiftedUntyped), List(Tagged(0), Tagged(2))) - signature: List[List[Fingerprint]], - // type arguments part of a macro impl ref (the right-hand side of a macro definition) - // these trees don't refer to a macro impl, so we can pickle them as is - targs: List[Tree]) { - + // Is this macro impl a bundle (a trait extending BlackboxMacro or WhiteboxMacro) or a vanilla def? + val isBundle: Boolean, + // Is this macro impl blackbox (i.e. having BlackboxContext in its signature)? + val isBlackbox: Boolean, + // Java class name of the class that contains the macro implementation + // is used to load the corresponding object with Java reflection + className: String, + // method name of the macro implementation + // `className` and `methName` are all we need to reflectively invoke a macro implementation + // because macro implementations cannot be overloaded + methName: String, + // flattens the macro impl's parameter lists having symbols replaced with their fingerprints + // currently fingerprints are calculated solely from types of the symbols: + // * c.Expr[T] => LiftedTyped + // * c.Tree => LiftedUntyped + // * c.WeakTypeTag[T] => Tagged(index of the type parameter corresponding to that type tag) + // * everything else (e.g. scala.reflect.macros.BlackboxContext/WhiteboxContext) => Other + // f.ex. for: def impl[T: WeakTypeTag, U, V: WeakTypeTag](c: BlackboxContext)(x: c.Expr[T], y: c.Tree): (U, V) = ??? + // `signature` will be equal to List(List(Other), List(LiftedTyped, LiftedUntyped), List(Tagged(0), Tagged(2))) + signature: List[List[Fingerprint]], + // type arguments part of a macro impl ref (the right-hand side of a macro definition) + // these trees don't refer to a macro impl, so we can pickle them as is + targs: List[Tree]) { // Was this binding derived from a `def ... = macro ???` definition? def is_??? = { val Predef_??? = currentRun.runDefinitions.Predef_??? className == Predef_???.owner.javaClassName && methName == Predef_???.name.encoded } + def isWhitebox = !isBlackbox } /** Macro def -> macro impl bindings are serialized into a `macroImpl` annotation * with synthetic content that carries the payload described in `MacroImplBinding`. * * For example, for a pair of macro definition and macro implementation: - * def impl(c: scala.reflect.macros.Context): c.Expr[Unit] = ??? + * def impl(c: scala.reflect.macros.BlackboxContext): c.Expr[Unit] = ??? * def foo: Unit = macro impl * * We will have the following annotation added on the macro definition `foo`: @@ -122,13 +124,14 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { * @scala.reflect.macros.internal.macroImpl( * `macro`( * "isBundle" = false, + * "isBlackbox" = true, * "signature" = List(Other), * "methodName" = "impl", * "versionFormat" = <current version format>, * "className" = "Macros$")) */ object MacroImplBinding { - val versionFormat = 5.0 + val versionFormat = 6.0 def pickleAtom(obj: Any): Tree = obj match { @@ -151,7 +154,7 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { def pickle(macroImplRef: Tree): Tree = { val runDefinitions = currentRun.runDefinitions import runDefinitions._ - val MacroImplReference(isBundle, owner, macroImpl, targs) = macroImplRef + val MacroImplReference(isBundle, isBlackbox, owner, macroImpl, targs) = macroImplRef // todo. refactor when fixing SI-5498 def className: String = { @@ -182,6 +185,7 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { val payload = List[(String, Any)]( "versionFormat" -> versionFormat, "isBundle" -> isBundle, + "isBlackbox" -> isBlackbox, "className" -> className, "methodName" -> macroImpl.name.toString, "signature" -> signature @@ -237,10 +241,11 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { if (versionFormat != pickleVersionFormat) fail(s"expected version format $versionFormat, actual $pickleVersionFormat") val isBundle = unpickle("isBundle", classOf[Boolean]) + val isBlackbox = unpickle("isBlackbox", classOf[Boolean]) val className = unpickle("className", classOf[String]) val methodName = unpickle("methodName", classOf[String]) val signature = unpickle("signature", classOf[List[List[Fingerprint]]]) - MacroImplBinding(isBundle, className, methodName, signature, targs) + MacroImplBinding(isBundle, isBlackbox, className, methodName, signature, targs) } } @@ -249,14 +254,17 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { macroDef withAnnotation AnnotationInfo(MacroImplAnnotation.tpe, List(pickle), Nil) } - def loadMacroImplBinding(macroDef: Symbol): MacroImplBinding = { - val Some(AnnotationInfo(_, List(pickle), _)) = macroDef.getAnnotation(MacroImplAnnotation) - MacroImplBinding.unpickle(pickle) - } + def loadMacroImplBinding(macroDef: Symbol): Option[MacroImplBinding] = + macroDef.getAnnotation(MacroImplAnnotation) collect { + case AnnotationInfo(_, List(pickle), _) => MacroImplBinding.unpickle(pickle) + } + + def isBlackbox(expandee: Tree): Boolean = isBlackbox(dissectApplied(expandee).core.symbol) + def isBlackbox(macroDef: Symbol): Boolean = loadMacroImplBinding(macroDef).map(_.isBlackbox).getOrElse(false) def computeMacroDefTypeFromMacroImplRef(macroDdef: DefDef, macroImplRef: Tree): Type = { macroImplRef match { - case MacroImplReference(_, _, macroImpl, targs) => + case MacroImplReference(_, _, _, macroImpl, targs) => // Step I. Transform c.Expr[T] to T and everything else to Any var runtimeType = decreaseMetalevel(macroImpl.info.finalResultType) @@ -450,7 +458,7 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { (trees :+ tags).flatten } - val binding = loadMacroImplBinding(macroDef) + val binding = loadMacroImplBinding(macroDef).get if (binding.is_???) Nil else calculateMacroArgs(binding) } @@ -459,7 +467,7 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { } /** Keeps track of macros in-flight. - * See more informations in comments to `openMacros` in `scala.reflect.macros.Context`. + * See more informations in comments to `openMacros` in `scala.reflect.macros.WhiteboxContext`. */ private var _openMacros = List[MacroContext]() def openMacros = _openMacros @@ -596,21 +604,27 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { */ def macroExpandApply(typer: Typer, expandee: Tree, mode: Mode, pt: Type): Tree = { object expander extends TermMacroExpander(APPLY_ROLE, typer, expandee, mode, pt) { - override def onSuccess(expanded: Tree) = { + override def onSuccess(expanded0: Tree) = { + def approximate(tp: Type) = { + // approximation is necessary for whitebox macros to guide type inference + // read more in the comments for onDelayed below + if (isBlackbox(expandee)) tp + else { + val undetparams = tp collect { case tp if tp.typeSymbol.isTypeParameter => tp.typeSymbol } + deriveTypeWithWildcards(undetparams)(tp) + } + } + val macroPt = approximate(if (isNullaryInvocation(expandee)) expandee.tpe.finalResultType else expandee.tpe) + val expanded = if (isBlackbox(expandee)) atPos(enclosingMacroPosition.focus)(Typed(expanded0, TypeTree(macroPt))) else expanded0 + // prematurely annotate the tree with a macro expansion attachment // so that adapt called indirectly by typer.typed knows that it needs to apply the existential fixup linkExpandeeAndExpanded(expandee, expanded) - // approximation is necessary for whitebox macros to guide type inference - // read more in the comments for onDelayed below - def approximate(tp: Type) = { - val undetparams = tp collect { case tp if tp.typeSymbol.isTypeParameter => tp.typeSymbol } - deriveTypeWithWildcards(undetparams)(tp) - } - val macroPtApprox = approximate(if (isNullaryInvocation(expandee)) expandee.tpe.finalResultType else expandee.tpe) + // `macroExpandApply` is called from `adapt`, where implicit conversions are disabled // therefore we need to re-enable the conversions back temporarily - if (macroDebugVerbose) println(s"typecheck #1 (against macroPtApprox = $macroPtApprox): $expanded") - val expanded1 = typer.context.withImplicitsEnabled(typer.typed(expanded, mode, macroPtApprox)) + if (macroDebugVerbose) println(s"typecheck #1 (against macroPt = $macroPt): $expanded") + val expanded1 = typer.context.withImplicitsEnabled(typer.typed(expanded, mode, macroPt)) if (expanded1.isErrorTyped) { if (macroDebugVerbose) println(s"typecheck #1 has failed: ${typer.context.reportBuffer.errors}") expanded1 @@ -664,7 +678,7 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { // e.g. for Foo it will be Int :: String :: Boolean :: HNil), there's no way to convey this information // to the typechecker. Therefore the typechecker will infer Nothing for L, which is hardly what we want. // - // =========== THE SOLUTION =========== + // =========== THE SOLUTION (ENABLED ONLY FOR WHITEBOX MACROS) =========== // // To give materializers a chance to say their word before vanilla inference kicks in, // we infer as much as possible (e.g. in the example above even though L is hopeless, C still can be inferred to Foo) @@ -672,9 +686,12 @@ trait Macros extends FastTrack with MacroRuntimes with Traces with Helpers { // Thanks to that the materializer can take a look at what's going on and react accordingly. val shouldInstantiate = typer.context.undetparams.nonEmpty && !mode.inPolyMode if (shouldInstantiate) { - forced += delayed - typer.infer.inferExprInstance(delayed, typer.context.extractUndetparams(), pt, keepNothings = false) - macroExpandApply(typer, delayed, mode, pt) + if (isBlackbox(expandee)) typer.instantiatePossiblyExpectingUnit(delayed, mode, pt) + else { + forced += delayed + typer.infer.inferExprInstance(delayed, typer.context.extractUndetparams(), pt, keepNothings = false) + macroExpandApply(typer, delayed, mode, pt) + } } else delayed } } |