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Diffstat (limited to 'src/compiler/scala/reflect/reify/codegen/Types.scala')
| -rw-r--r-- | src/compiler/scala/reflect/reify/codegen/Types.scala | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/src/compiler/scala/reflect/reify/codegen/Types.scala b/src/compiler/scala/reflect/reify/codegen/Types.scala new file mode 100644 index 0000000000..6f3a60a076 --- /dev/null +++ b/src/compiler/scala/reflect/reify/codegen/Types.scala @@ -0,0 +1,226 @@ +package scala.reflect.reify +package codegen + +trait Types { + self: Reifier => + + import mirror._ + import definitions._ + import treeInfo._ + + /** + * Reify a type. + * For internal use only, use ``reified'' instead. + */ + def reifyType(tpe0: Type): Tree = { + assert(tpe0 != null, "tpe is null") + val tpe = tpe0.dealias + + if (tpe.isErroneous) + CannotReifyErroneousReifee(tpe) + if (tpe.isLocalToReifee) + CannotReifyType(tpe) + + // [Eugene] how do I check that the substitution is legal w.r.t tpe.info? + val spliced = spliceType(tpe) + if (spliced != EmptyTree) + return spliced + + val tsym = tpe.typeSymbol + if (tsym.isClass && tpe == tsym.typeConstructor && tsym.isStatic) + Select(reify(tpe.typeSymbol), nme.asTypeConstructor) + else tpe match { + case tpe @ NoType => + reifyMirrorObject(tpe) + case tpe @ NoPrefix => + reifyMirrorObject(tpe) + case tpe @ ThisType(root) if root == RootClass => + mirrorSelect("definitions.RootClass.thisPrefix") + case tpe @ ThisType(empty) if empty == EmptyPackageClass => + mirrorSelect("definitions.EmptyPackageClass.thisPrefix") + case tpe @ ThisType(clazz) if clazz.isModuleClass && clazz.isStatic => + mirrorCall(nme.thisModuleType, reify(clazz.fullName)) + case tpe @ ThisType(_) => + reifyProduct(tpe) + case tpe @ SuperType(thistpe, supertpe) => + reifyProduct(tpe) + case tpe @ SingleType(pre, sym) => + reifyProduct(tpe) + case tpe @ ConstantType(value) => + mirrorFactoryCall(nme.ConstantType, reifyProduct(value)) + case tpe @ TypeRef(pre, sym, args) => + reifyProduct(tpe) + case tpe @ TypeBounds(lo, hi) => + reifyProduct(tpe) + case tpe @ NullaryMethodType(restpe) => + reifyProduct(tpe) + case tpe @ AnnotatedType(anns, underlying, selfsym) => +// reifyAnnotatedType(tpe) + CannotReifyType(tpe) + case _ => +// reifyToughType(tpe) + CannotReifyType(tpe) + } + } + + /** An obscure flag necessary for implicit TypeTag generation */ + private var spliceTypesEnabled = !dontSpliceAtTopLevel + + /** Keeps track of whether this reification contains abstract type parameters */ + var maybeGround = true + var definitelyGround = true + + def eligibleForSplicing(tpe: Type): Boolean = { + // [Eugene] is this comprehensive? + // the only thingies that we want to splice are: 1) type parameters, 2) type members + // this check seems to cover them all, right? + tpe.isInstanceOf[TypeRef] && tpe.typeSymbol.isAbstractType + } + + private type SpliceCacheKey = (Symbol, Symbol) + private lazy val spliceCache: collection.mutable.Map[SpliceCacheKey, Tree] = { + val cache = analyzer.perRunMacroCache.getOrElseUpdate(MacroContextReify, collection.mutable.Map[Any, Any]()) + cache.getOrElseUpdate("spliceCache", collection.mutable.Map[SpliceCacheKey, Tree]()).asInstanceOf[collection.mutable.Map[SpliceCacheKey, Tree]] + } + + def spliceType(tpe: Type): Tree = { + if (eligibleForSplicing(tpe)) { + if (reifyDebug) println("splicing " + tpe) + + if (spliceTypesEnabled) { + var tagClass = if (requireGroundTypeTag) GroundTypeTagClass else TypeTagClass + val tagTpe = singleType(prefix.tpe, prefix.tpe member tagClass.name) + + // [Eugene] this should be enough for an abstract type, right? + val key = (tagClass, tpe.typeSymbol) + if (reifyDebug && spliceCache.contains(key)) println("cache hit: " + spliceCache(key)) + val result = spliceCache.getOrElseUpdate(key, { + // if this fails, it might produce the dreaded "erroneous or inaccessible type" error + // to find out the whereabouts of the error run scalac with -Ydebug + if (reifyDebug) println("launching implicit search for %s.%s[%s]".format(prefix, tagClass.name, tpe)) + val positionBearer = mirror.analyzer.openMacros.find(c => c.macroApplication.pos != NoPosition).map(_.macroApplication).getOrElse(EmptyTree).asInstanceOf[Tree] + typer.resolveTypeTag(positionBearer, prefix.tpe, tpe, requireGroundTypeTag) match { + case failure if failure.isEmpty => + if (reifyDebug) println("implicit search was fruitless") + definitelyGround &= false + maybeGround &= false + EmptyTree + case success => + if (reifyDebug) println("implicit search has produced a result: " + success) + definitelyGround |= requireGroundTypeTag + maybeGround |= true + var splice = Select(success, nme.tpe) + splice match { + case InlinedTypeSplice(_, inlinedSymbolTable, tpe) => + // all free vars local to the enclosing reifee should've already been inlined by ``Metalevels'' + inlinedSymbolTable foreach { case freedef @ FreeDef(_, _, binding, _) => assert(!binding.symbol.isLocalToReifee, freedef) } + symbolTable ++= inlinedSymbolTable + reifyTrace("inlined the splicee: ")(tpe) + case tpe => + tpe + } + } + }) + if (result != EmptyTree) return result.duplicate + } else { + if (reifyDebug) println("splicing has been cancelled: spliceTypesEnabled = false") + } + + if (requireGroundTypeTag) + CannotReifyGroundTypeTagHavingUnresolvedTypeParameters(tpe) + } + + spliceTypesEnabled = true + EmptyTree + } + + // yet another thingie disabled for simplicity + // in principle, we could retain and reify AnnotatedTypes + // but that'd require reifying every type and symbol inside ann.args + // however, since we've given up on tough types for the moment, the former would be problematic +// private def reifyAnnotatedType(tpe: AnnotatedType): Tree = { +// // ``Reshaper'' transforms annotation infos from symbols back into Modifier.annotations, which are trees +// // so the only place on Earth that can lead to reification of AnnotationInfos is the Ay Tee Land +// // therefore this function is as local as possible, don't move it out of this scope +// def reifyAnnotationInfo(ann: AnnotationInfo): Tree = { +// val reifiedArgs = ann.args map { arg => +// val saved1 = reifyTreeSymbols +// val saved2 = reifyTreeTypes +// +// try { +// // one more quirk of reifying annotations +// // +// // when reifying AnnotatedTypes we need to reify all the types and symbols of inner ASTs +// // that's because a lot of logic expects post-typer trees to have non-null tpes +// // +// // Q: reified trees are pre-typer, so there's shouldn't be a problem. +// // reflective typechecker will fill in missing symbols and types, right? +// // A: actually, no. annotation ASTs live inside AnnotatedTypes, +// // and insides of the types is the place where typechecker doesn't look. +// reifyTreeSymbols = true +// reifyTreeTypes = true +// +// // todo. every AnnotationInfo is an island, entire of itself +// // no regular Traverser or Transformer can reach it +// // hence we need to run its contents through the entire reification pipeline +// // e.g. to apply reshaping or to check metalevels +// reify(arg) +// } finally { +// reifyTreeSymbols = saved1 +// reifyTreeTypes = saved2 +// } +// } +// +// def reifyClassfileAnnotArg(arg: ClassfileAnnotArg): Tree = arg match { +// case LiteralAnnotArg(const) => +// mirrorFactoryCall(nme.LiteralAnnotArg, reifyProduct(const)) +// case ArrayAnnotArg(args) => +// mirrorFactoryCall(nme.ArrayAnnotArg, scalaFactoryCall(nme.Array, args map reifyClassfileAnnotArg: _*)) +// case NestedAnnotArg(ann) => +// mirrorFactoryCall(nme.NestedAnnotArg, reifyAnnotationInfo(ann)) +// } +// +// // if you reify originals of anns, you get SO when trying to reify AnnotatedTypes, so screw it - after all, it's not that important +// val reifiedAssocs = ann.assocs map (assoc => scalaFactoryCall(nme.Tuple2, reify(assoc._1), reifyClassfileAnnotArg(assoc._2))) +// mirrorFactoryCall(nme.AnnotationInfo, reify(ann.atp), mkList(reifiedArgs), mkList(reifiedAssocs)) +// } +// +// val AnnotatedType(anns, underlying, selfsym) = tpe +// mirrorFactoryCall(nme.AnnotatedType, mkList(anns map reifyAnnotationInfo), reify(underlying), reify(selfsym)) +// } + + // previous solution to reifying tough types involved creating dummy symbols (see ``registerReifiableSymbol'' calls below) + // however such symbols lost all the connections with their origins and became almost useless, except for typechecking + // hence this approach was replaced by less powerful, but more principled one based on ``reifyFreeType'' + // it's possible that later on we will revise and revive ``reifyToughType'', but for now it's disabled under an implementation restriction +// /** Reify a tough type, i.e. the one that leads to creation of auxiliary symbols */ +// // This is the uncharted territory in the reifier +// private def reifyToughType(tpe: Type): Tree = { +// if (reifyDebug) println("tough type: %s (%s)".format(tpe, tpe.kind)) +// +// def reifyScope(scope: Scope): Tree = { +// scope foreach registerReifiableSymbol +// mirrorCall(nme.newScopeWith, scope.toList map reify: _*) +// } +// +// tpe match { +// case tpe @ RefinedType(parents, decls) => +// registerReifiableSymbol(tpe.typeSymbol) +// mirrorFactoryCall(tpe, reify(parents), reifyScope(decls), reify(tpe.typeSymbol)) +// case tpe @ ExistentialType(tparams, underlying) => +// tparams foreach registerReifiableSymbol +// mirrorFactoryCall(tpe, reify(tparams), reify(underlying)) +// case tpe @ ClassInfoType(parents, decls, clazz) => +// registerReifiableSymbol(clazz) +// mirrorFactoryCall(tpe, reify(parents), reifyScope(decls), reify(tpe.typeSymbol)) +// case tpe @ MethodType(params, restpe) => +// params foreach registerReifiableSymbol +// mirrorFactoryCall(tpe, reify(params), reify(restpe)) +// case tpe @ PolyType(tparams, underlying) => +// tparams foreach registerReifiableSymbol +// mirrorFactoryCall(tpe, reify(tparams), reify(underlying)) +// case _ => +// throw new Error("internal error: %s (%s) is not supported".format(tpe, tpe.kind)) +// } +// } +}
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