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Diffstat (limited to 'src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala')
-rw-r--r-- | src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala new file mode 100644 index 0000000000..e5b4c4a6c2 --- /dev/null +++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala @@ -0,0 +1,130 @@ +/* NSC -- new Scala compiler + * Copyright 2005-2014 LAMP/EPFL + * @author Martin Odersky + */ + +package scala.tools.nsc.backend.jvm + +import scala.tools.nsc.Global +import PartialFunction._ + +/** + * This trait contains code shared between GenBCode and GenASM that depends on types defined in + * the compiler cake (Global). + */ +final class BCodeAsmCommon[G <: Global](val global: G) { + import global._ + + /** + * True if `classSym` is an anonymous class or a local class. I.e., false if `classSym` is a + * member class. This method is used to decide if we should emit an EnclosingMethod attribute. + * It is also used to decide whether the "owner" field in the InnerClass attribute should be + * null. + */ + def isAnonymousOrLocalClass(classSym: Symbol): Boolean = { + def isDelambdafyLambdaClass(classSym: Symbol): Boolean = { + classSym.isAnonymousFunction && (settings.Ydelambdafy.value == "method") + } + + assert(classSym.isClass, s"not a class: $classSym") + + !isDelambdafyLambdaClass(classSym) && + (classSym.isAnonymousClass || !classSym.originalOwner.isClass) + } + + /** + * Returns the enclosing method for non-member classes. In the following example + * + * class A { + * def f = { + * class B { + * class C + * } + * } + * } + * + * the method returns Some(f) for B, but None for C, because C is a member class. For non-member + * classes that are not enclosed by a method, it returns None: + * + * class A { + * { class B } + * } + * + * In this case, for B, we return None. + * + * The EnclosingMethod attribute needs to be added to non-member classes (see doc in BTypes). + * This is a source-level property, so we need to use the originalOwner chain to reconstruct it. + */ + private def enclosingMethodForEnclosingMethodAttribute(classSym: Symbol): Option[Symbol] = { + assert(classSym.isClass, classSym) + def enclosingMethod(sym: Symbol): Option[Symbol] = { + if (sym.isClass || sym == NoSymbol) None + else if (sym.isMethod) Some(sym) + else enclosingMethod(sym.originalOwner) + } + enclosingMethod(classSym.originalOwner) + } + + /** + * The enclosing class for emitting the EnclosingMethod attribute. Since this is a source-level + * property, this method looks at the originalOwner chain. See doc in BTypes. + */ + private def enclosingClassForEnclosingMethodAttribute(classSym: Symbol): Symbol = { + assert(classSym.isClass, classSym) + def enclosingClass(sym: Symbol): Symbol = { + if (sym.isClass) sym + else enclosingClass(sym.originalOwner) + } + enclosingClass(classSym.originalOwner) + } + + final case class EnclosingMethodEntry(owner: String, name: String, methodDescriptor: String) + + /** + * If data for emitting an EnclosingMethod attribute. None if `classSym` is a member class (not + * an anonymous or local class). See doc in BTypes. + * + * The class is parametrized by two functions to obtain a bytecode class descriptor for a class + * symbol, and to obtain a method signature descriptor fro a method symbol. These function depend + * on the implementation of GenASM / GenBCode, so they need to be passed in. + */ + def enclosingMethodAttribute(classSym: Symbol, classDesc: Symbol => String, methodDesc: Symbol => String): Option[EnclosingMethodEntry] = { + if (isAnonymousOrLocalClass(classSym)) { + val methodOpt = enclosingMethodForEnclosingMethodAttribute(classSym) + debuglog(s"enclosing method for $classSym is $methodOpt (in ${methodOpt.map(_.enclClass)})") + Some(EnclosingMethodEntry( + classDesc(enclosingClassForEnclosingMethodAttribute(classSym)), + methodOpt.map(_.javaSimpleName.toString).orNull, + methodOpt.map(methodDesc).orNull)) + } else { + None + } + } + + /** + * This is basically a re-implementation of sym.isStaticOwner, but using the originalOwner chain. + * + * The problem is that we are interested in a source-level property. Various phases changed the + * symbol's properties in the meantime, mostly lambdalift modified (destructively) the owner. + * Therefore, `sym.isStatic` is not what we want. For example, in + * object T { def f { object U } } + * the owner of U is T, so UModuleClass.isStatic is true. Phase travel does not help here. + */ + def isOriginallyStaticOwner(sym: Symbol): Boolean = { + sym.isPackageClass || sym.isModuleClass && isOriginallyStaticOwner(sym.originalOwner) + } + + /** + * The member classes of a class symbol. Note that the result of this method depends on the + * current phase, for example, after lambdalift, all local classes become member of the enclosing + * class. + */ + def memberClassesOf(classSymbol: Symbol): List[Symbol] = classSymbol.info.decls.collect({ + case sym if sym.isClass => + sym + case sym if sym.isModule => + val r = exitingPickler(sym.moduleClass) + assert(r != NoSymbol, sym.fullLocationString) + r + })(collection.breakOut) +} |