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Diffstat (limited to 'src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala b/src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala new file mode 100644 index 0000000000..28f620dbb5 --- /dev/null +++ b/src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala @@ -0,0 +1,225 @@ +/* NSC -- new Scala compiler + * Copyright 2005-2013 LAMP/EPFL + * @author Martin Odersky + */ + +package scala.tools.nsc +package typechecker + +/** + * @author Lukas Rytz + * @version 1.0 + */ +trait AnalyzerPlugins { self: Analyzer => + import global._ + + + trait AnalyzerPlugin { + /** + * Selectively activate this analyzer plugin, e.g. according to the compiler phase. + * + * Note that the current phase can differ from the global compiler phase (look for `enteringPhase` + * invocations in the compiler). For instance, lazy types created by the UnPickler are completed + * at the phase in which their symbol is created. Observations show that this can even be the + * parser phase. Since symbol completion can trigger subtyping, typing etc, your plugin might + * need to be active also in phases other than namer and typer. + * + * Typically, this method can be implemented as + * + * global.phase.id < global.currentRun.picklerPhase.id + */ + def isActive(): Boolean = true + + /** + * Let analyzer plugins change the expected type before type checking a tree. + */ + def pluginsPt(pt: Type, typer: Typer, tree: Tree, mode: Int): Type = pt + + /** + * Let analyzer plugins modify the type that has been computed for a tree. + * + * @param tpe The type inferred by the type checker, initially (for first plugin) `tree.tpe` + * @param typer The yper that type checked `tree` + * @param tree The type-checked tree + * @param mode Mode that was used for typing `tree` + * @param pt Expected type that was used for typing `tree` + */ + def pluginsTyped(tpe: Type, typer: Typer, tree: Tree, mode: Int, pt: Type): Type = tpe + + /** + * Let analyzer plugins change the types assigned to definitions. For definitions that have + * an annotated type, the assigned type is obtained by typing that type tree. Otherwise, the + * type is inferred by typing the definition's righthand side. + * + * In order to know if the type was inferred, you can query the `wasEmpty` field in the `tpt` + * TypeTree of the definition (for DefDef and ValDef). + * + * (*) If the type of a method or value is inferred, the type-checked tree is stored in the + * `analyzer.transformed` hash map, indexed by the definition's rhs tree. + * + * NOTE: Invoking the type checker can lead to cyclic reference errors. For instance, if this + * method is called from the type completer of a recursive method, type checking the mehtod + * rhs will invoke the same completer again. It might be possible to avoid this situation by + * assigning `tpe` to `defTree.symbol` (untested) - the final type computed by this method + * will then be assigned to the definition's symbol by monoTypeCompleter (in Namers). + * + * The hooks into `typeSig` allow analyzer plugins to add annotations to (or change the types + * of) definition symbols. This cannot not be achieved by using `pluginsTyped`: this method + * is only called during type checking, so changing the type of a symbol at this point is too + * late: references to the symbol might already be typed and therefore obtain the the original + * type assigned during naming. + * + * @param defTree is the definition for which the type was computed. The different cases are + * outlined below. Note that this type is untyped (for methods and values with inferred type, + * the typed rhs trees are available in analyzer.transformed). + * + * Case defTree: Template + * - tpe : A ClassInfoType for the template + * - typer: The typer for template members, i.e. expressions and definitions of defTree.body + * - pt : WildcardType + * - the class symbol is accessible through typer.context.owner + * + * Case defTree: ClassDef + * - tpe : A ClassInfoType, or a PolyType(params, ClassInfoType) for polymorphic classes. + * The class type is the one computed by templateSig, i.e. through the above case + * - typer: The typer for the class. Note that this typer has a different context than the + * typer for the template. + * - pt : WildcardType + * + * Case defTree: ModuleDef + * - tpe : A ClassInfoType computed by templateSig + * - typer: The typer for the module. context.owner of this typer is the module class symbol + * - pt : WildcardType + * + * Case defTree: DefDef + * - tpe : The type of the method (MethodType, PolyType or NullaryMethodType). (*) + * - typer: The typer the rhs of this method + * - pt : If tpt.isEmpty, either the result type from the overridden method, or WildcardType. + * Otherwise the type obtained from typing tpt. + * - Note that for constructors, pt is the class type which the constructor creates. To type + * check the rhs of the constructor however, the expected type has to be WildcardType (see + * Typers.typedDefDef) + * + * Case defTree: ValDef + * - tpe : The type of this value. (*) + * - typer: The typer for the rhs of this value + * - pt : If tpt.isEmpty, WildcardType. Otherwise the type obtained from typing tpt. + * - Note that pluginsTypeSig might be called multiple times for the same ValDef since it is + * used to compute the types of the accessor methods (see `pluginsTypeSigAccessor`) + * + * Case defTree: TypeDef + * - tpe : The type obtained from typing rhs (PolyType if the TypeDef defines a polymorphic type) + * - typer: The typer for the rhs of this type + * - pt : WildcardType + */ + def pluginsTypeSig(tpe: Type, typer: Typer, defTree: Tree, pt: Type): Type = tpe + + /** + * Modify the types of field accessors. The namer phase creates method types for getters and + * setters based on the type of the corresponding field. + * + * Note: in order to compute the method type of an accessor, the namer calls `typeSig` on the + * `ValDef` tree of the corresponding field. This implies that the `pluginsTypeSig` method + * is potentially called multiple times for the same ValDef tree. + * + * @param tpe The method type created by the namer for the accessor + * @param typer The typer for the ValDef (not for the rhs) + * @param tree The ValDef corresponding to the accessor + * @param sym The accessor method symbol (getter, setter, beanGetter or beanSetter) + */ + def pluginsTypeSigAccessor(tpe: Type, typer: Typer, tree: ValDef, sym: Symbol): Type = tpe + + /** + * Decide whether this analyzer plugin can adapt a tree that has an annotated type to the + * given type tp, taking into account the given mode (see method adapt in trait Typers). + */ + def canAdaptAnnotations(tree: Tree, typer: Typer, mode: Int, pt: Type): Boolean = false + + /** + * Adapt a tree that has an annotated type to the given type tp, taking into account the given + * mode (see method adapt in trait Typers). + * + * An implementation cannot rely on canAdaptAnnotations being called before. If the implementing + * class cannot do the adapting, it should return the tree unchanged. + */ + def adaptAnnotations(tree: Tree, typer: Typer, mode: Int, pt: Type): Tree = tree + + /** + * Modify the type of a return expression. By default, return expressions have type + * NothingClass.tpe. + * + * @param tpe The type of the return expression + * @param typer The typer that was used for typing the return tree + * @param tree The typed return expression tree + * @param pt The return type of the enclosing method + */ + def pluginsTypedReturn(tpe: Type, typer: Typer, tree: Return, pt: Type): Type = tpe + } + + + + /** A list of registered analyzer plugins */ + private var analyzerPlugins: List[AnalyzerPlugin] = Nil + + /** Registers a new analyzer plugin */ + def addAnalyzerPlugin(plugin: AnalyzerPlugin) { + if (!analyzerPlugins.contains(plugin)) + analyzerPlugins = plugin :: analyzerPlugins + } + + + /** @see AnalyzerPlugin.pluginsPt */ + def pluginsPt(pt: Type, typer: Typer, tree: Tree, mode: Int): Type = + if (analyzerPlugins.isEmpty) pt + else analyzerPlugins.foldLeft(pt)((pt, plugin) => + if (!plugin.isActive()) pt else plugin.pluginsPt(pt, typer, tree, mode)) + + /** @see AnalyzerPlugin.pluginsTyped */ + def pluginsTyped(tpe: Type, typer: Typer, tree: Tree, mode: Int, pt: Type): Type = { + // support deprecated methods in annotation checkers + val annotCheckersTpe = addAnnotations(tree, tpe) + if (analyzerPlugins.isEmpty) annotCheckersTpe + else analyzerPlugins.foldLeft(annotCheckersTpe)((tpe, plugin) => + if (!plugin.isActive()) tpe else plugin.pluginsTyped(tpe, typer, tree, mode, pt)) + } + + /** @see AnalyzerPlugin.pluginsTypeSig */ + def pluginsTypeSig(tpe: Type, typer: Typer, defTree: Tree, pt: Type): Type = + if (analyzerPlugins.isEmpty) tpe + else analyzerPlugins.foldLeft(tpe)((tpe, plugin) => + if (!plugin.isActive()) tpe else plugin.pluginsTypeSig(tpe, typer, defTree, pt)) + + /** @see AnalyzerPlugin.pluginsTypeSigAccessor */ + def pluginsTypeSigAccessor(tpe: Type, typer: Typer, tree: ValDef, sym: Symbol): Type = + if (analyzerPlugins.isEmpty) tpe + else analyzerPlugins.foldLeft(tpe)((tpe, plugin) => + if (!plugin.isActive()) tpe else plugin.pluginsTypeSigAccessor(tpe, typer, tree, sym)) + + /** @see AnalyzerPlugin.canAdaptAnnotations */ + def canAdaptAnnotations(tree: Tree, typer: Typer, mode: Int, pt: Type): Boolean = { + // support deprecated methods in annotation checkers + val annotCheckersExists = global.canAdaptAnnotations(tree, mode, pt) + annotCheckersExists || { + if (analyzerPlugins.isEmpty) false + else analyzerPlugins.exists(plugin => + plugin.isActive() && plugin.canAdaptAnnotations(tree, typer, mode, pt)) + } + } + + /** @see AnalyzerPlugin.adaptAnnotations */ + def adaptAnnotations(tree: Tree, typer: Typer, mode: Int, pt: Type): Tree = { + // support deprecated methods in annotation checkers + val annotCheckersTree = global.adaptAnnotations(tree, mode, pt) + if (analyzerPlugins.isEmpty) annotCheckersTree + else analyzerPlugins.foldLeft(annotCheckersTree)((tree, plugin) => + if (!plugin.isActive()) tree else plugin.adaptAnnotations(tree, typer, mode, pt)) + } + + /** @see AnalyzerPlugin.pluginsTypedReturn */ + def pluginsTypedReturn(tpe: Type, typer: Typer, tree: Return, pt: Type): Type = { + val annotCheckersType = adaptTypeOfReturn(tree.expr, pt, tpe) + if (analyzerPlugins.isEmpty) annotCheckersType + else analyzerPlugins.foldLeft(annotCheckersType)((tpe, plugin) => + if (!plugin.isActive()) tpe else plugin.pluginsTypedReturn(tpe, typer, tree, pt)) + } +} |