Move ICodeReader-specific logic out of ClassfileParser.

gkossakowski · gkossakowski · commit ced7214959c0 · 2013-07-27T14:09:39.000-07:00
ClassfileParser contained some ICodeReader-specific logic
like `forceMangledName` and `getMemberSymbol` methods.

The `getMemberSymbol` method was defined in ConstantPool class
because it must access some internal state of ConstantPool. In order
to move that method to ICodeReader we had two options:

  1. Make all internal state accessible from outside of ConstantPool
     class so getMemberSymbol could be implemented outside of
     ConstantPool hierarchy
  2. Make it possible to subclass ConstantPool in ICodeReader so
     getMemberSymbol can be implemented in a subclass and can access
     internal state of ConstantPool

Given the fact that getMemberSymbol mutates ConstantPool's internal
state I decided that subclassing is a cleaner approach. It required
significant refactoring because we had to make sure that we create
an instance of proper class when initializing the `pool` variable.
I ended up introducing `ConstantPoolManager` class which is essentially
a mutable variable that can be reset multiple times.

This change makes ClassfileParser independent from the ICodeReader and
its implementation details.
diff --git a/src/compiler/scala/tools/nsc/symtab/SymbolLoaders.scala b/src/compiler/scala/tools/nsc/symtab/SymbolLoaders.scala
@@ -246,7 +246,10 @@ abstract class SymbolLoaders {
   class ClassfileLoader(val classfile: AbstractFile) extends SymbolLoader with FlagAssigningCompleter {
     private object classfileParser extends {
       val global: SymbolLoaders.this.global.type = SymbolLoaders.this.global
-    } with ClassfileParser
+    } with ClassfileParser {
+      override protected type ThisConstantPool = ConstantPool
+      override protected def newConstantPool: ThisConstantPool = new ConstantPool
+    }
 
     protected def description = "class file "+ classfile.toString
 
diff --git a/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala b/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
@@ -30,12 +30,15 @@ abstract class ClassfileParser {
   import scala.reflect.internal.ClassfileConstants._
   import Flags._
 
+  protected type ThisConstantPool <: ConstantPool
+  protected def newConstantPool: ThisConstantPool
+
   protected var in: AbstractFileReader = _  // the class file reader
   protected var clazz: Symbol = _           // the class symbol containing dynamic members
   protected var staticModule: Symbol = _    // the module symbol containing static members
   protected var instanceScope: Scope = _    // the scope of all instance definitions
   protected var staticScope: Scope = _      // the scope of all static definitions
-  protected var pool: ConstantPool = _      // the classfile's constant pool
+  protected var pool: ThisConstantPool = _  // the classfile's constant pool
   protected var isScala: Boolean = _        // does class file describe a scala class?
   protected var isScalaAnnot: Boolean = _   // does class file describe a scala class with its pickled info in an annotation?
   protected var isScalaRaw: Boolean = _     // this class file is a scala class with no pickled info
@@ -119,7 +122,7 @@ abstract class ClassfileParser {
       this.isScala      = false
 
       parseHeader()
-      this.pool = new ConstantPool
+      this.pool = newConstantPool
       parseClass()
     }
   }
@@ -134,11 +137,14 @@ abstract class ClassfileParser {
       abort(s"class file ${in.file} has unknown version $major.$minor, should be at least $JAVA_MAJOR_VERSION.$JAVA_MINOR_VERSION")
   }
 
-  class ConstantPool {
-    private val len          = u2
-    private val starts       = new Array[Int](len)
-    private val values       = new Array[AnyRef](len)
-    private val internalized = new Array[Name](len)
+  /**
+   * Constructor of this class should not be called directly, use `newConstantPool` instead.
+   */
+  protected class ConstantPool {
+    protected val len          = u2
+    protected val starts       = new Array[Int](len)
+    protected val values       = new Array[AnyRef](len)
+    protected val internalized = new Array[Name](len)
 
     { var i = 1
       while (i < starts.length) {
@@ -212,76 +218,13 @@ abstract class ClassfileParser {
       getExternalName((in getChar start).toInt)
     }
 
-    /** Return the symbol of the class member at `index`.
-     *  The following special cases exist:
-     *   - If the member refers to special `MODULE$` static field, return
-     *  the symbol of the corresponding module.
-     *   - If the member is a field, and is not found with the given name,
-     *     another try is made by appending `nme.LOCAL_SUFFIX_STRING`
-     *   - If no symbol is found in the right tpe, a new try is made in the
-     *     companion class, in case the owner is an implementation class.
-     */
-    def getMemberSymbol(index: Int, static: Boolean): Symbol = {
-      if (index <= 0 || len <= index) errorBadIndex(index)
-      var f = values(index).asInstanceOf[Symbol]
-      if (f eq null) {
-        val start = starts(index)
-        val first = in.buf(start).toInt
-        if (first != CONSTANT_FIELDREF &&
-            first != CONSTANT_METHODREF &&
-            first != CONSTANT_INTFMETHODREF) errorBadTag(start)
-        val ownerTpe = getClassOrArrayType(in.getChar(start + 1).toInt)
-        debuglog("getMemberSymbol(static: " + static + "): owner type: " + ownerTpe + " " + ownerTpe.typeSymbol.originalName)
-        val (name0, tpe0) = getNameAndType(in.getChar(start + 3).toInt, ownerTpe)
-        debuglog("getMemberSymbol: name and tpe: " + name0 + ": " + tpe0)
-
-        forceMangledName(tpe0.typeSymbol.name, module = false)
-        val (name, tpe) = getNameAndType(in.getChar(start + 3).toInt, ownerTpe)
-        if (name == nme.MODULE_INSTANCE_FIELD) {
-          val index = in.getChar(start + 1).toInt
-          val name = getExternalName(in.getChar(starts(index).toInt + 1).toInt)
-          //assert(name.endsWith("$"), "Not a module class: " + name)
-          f = forceMangledName(name dropRight 1, module = true)
-          if (f == NoSymbol)
-            f = rootMirror.getModuleByName(name dropRight 1)
-        } else {
-          val origName = nme.unexpandedName(name)
-          val owner = if (static) ownerTpe.typeSymbol.linkedClassOfClass else ownerTpe.typeSymbol
-          f = owner.info.findMember(origName, 0, 0, stableOnly = false).suchThat(_.tpe.widen =:= tpe)
-          if (f == NoSymbol)
-            f = owner.info.findMember(newTermName(origName + nme.LOCAL_SUFFIX_STRING), 0, 0, stableOnly = false).suchThat(_.tpe =:= tpe)
-          if (f == NoSymbol) {
-            // if it's an impl class, try to find it's static member inside the class
-            if (ownerTpe.typeSymbol.isImplClass) {
-              f = ownerTpe.findMember(origName, 0, 0, stableOnly = false).suchThat(_.tpe =:= tpe)
-            } else {
-              log("Couldn't find " + name + ": " + tpe + " inside: \n" + ownerTpe)
-              f = tpe match {
-                case MethodType(_, _) => owner.newMethod(name.toTermName, owner.pos)
-                case _                => owner.newVariable(name.toTermName, owner.pos)
-              }
-              f setInfo tpe
-              log("created fake member " + f.fullName)
-            }
-          }
-        }
-        assert(f != NoSymbol,
-          s"could not find $name: $tpe in $ownerTpe" + (
-            if (settings.debug.value) ownerTpe.members.mkString(", members are:\n  ", "\n  ", "") else ""
-          )
-        )
-        values(index) = f
-      }
-      f
-    }
-
     /** Return a name and a type at the given index. If the type is a method
      *  type, a dummy symbol is created in `ownerTpe`, which is used as the
      *  owner of its value parameters. This might lead to inconsistencies,
      *  if a symbol of the given name already exists, and has a different
      *  type.
      */
-    private def getNameAndType(index: Int, ownerTpe: Type): (Name, Type) = {
+    protected def getNameAndType(index: Int, ownerTpe: Type): (Name, Type) = {
       if (index <= 0 || len <= index) errorBadIndex(index)
       values(index) match {
         case p: ((Name @unchecked, Type @unchecked)) => p
@@ -381,35 +324,14 @@ abstract class ClassfileParser {
     }
 
     /** Throws an exception signaling a bad constant index. */
-    private def errorBadIndex(index: Int) =
+    protected def errorBadIndex(index: Int) =
       abort(s"bad constant pool index: $index at pos: ${in.bp}")
 
     /** Throws an exception signaling a bad tag at given address. */
-    private def errorBadTag(start: Int) =
+    protected def errorBadTag(start: Int) =
       abort("bad constant pool tag ${in.buf(start)} at byte $start")
   }
 
-  /** Try to force the chain of enclosing classes for the given name. Otherwise
-   *  flatten would not lift classes that were not referenced in the source code.
-   */
-  def forceMangledName(name: Name, module: Boolean): Symbol = {
-    val parts = name.decode.toString.split(Array('.', '$'))
-    var sym: Symbol = rootMirror.RootClass
-
-    // was "at flatten.prev"
-    enteringFlatten {
-      for (part0 <- parts; if !(part0 == ""); part = newTermName(part0)) {
-        val sym1 = enteringIcode {
-          sym.linkedClassOfClass.info
-          sym.info.decl(part.encode)
-        }//.suchThat(module == _.isModule)
-
-        sym = sym1 orElse sym.info.decl(part.encode.toTypeName)
-      }
-    }
-    sym
-  }
-
   private def loadClassSymbol(name: Name): Symbol = {
     val file = global.classPath findSourceFile ("" +name) getOrElse {
       // SI-5593 Scaladoc's current strategy is to visit all packages in search of user code that can be documented
diff --git a/src/compiler/scala/tools/nsc/symtab/classfile/ICodeReader.scala b/src/compiler/scala/tools/nsc/symtab/classfile/ICodeReader.scala
@@ -28,6 +28,95 @@ abstract class ICodeReader extends ClassfileParser {
   var method: IMethod = NoIMethod          // the current IMethod
   var isScalaModule = false
 
+  override protected type ThisConstantPool = ICodeConstantPool
+  override protected def newConstantPool = new ICodeConstantPool
+
+  /** Try to force the chain of enclosing classes for the given name. Otherwise
+   *  flatten would not lift classes that were not referenced in the source code.
+   */
+  def forceMangledName(name: Name, module: Boolean): Symbol = {
+    val parts = name.decode.toString.split(Array('.', '$'))
+    var sym: Symbol = rootMirror.RootClass
+
+    // was "at flatten.prev"
+    enteringFlatten {
+      for (part0 <- parts; if !(part0 == ""); part = newTermName(part0)) {
+        val sym1 = enteringIcode {
+          sym.linkedClassOfClass.info
+          sym.info.decl(part.encode)
+        }//.suchThat(module == _.isModule)
+
+        sym = sym1 orElse sym.info.decl(part.encode.toTypeName)
+      }
+    }
+    sym
+  }
+
+  protected class ICodeConstantPool extends ConstantPool {
+    /** Return the symbol of the class member at `index`.
+     *  The following special cases exist:
+     *   - If the member refers to special `MODULE$` static field, return
+     *  the symbol of the corresponding module.
+     *   - If the member is a field, and is not found with the given name,
+     *     another try is made by appending `nme.LOCAL_SUFFIX_STRING`
+     *   - If no symbol is found in the right tpe, a new try is made in the
+     *     companion class, in case the owner is an implementation class.
+     */
+    def getMemberSymbol(index: Int, static: Boolean): Symbol = {
+      if (index <= 0 || len <= index) errorBadIndex(index)
+      var f = values(index).asInstanceOf[Symbol]
+      if (f eq null) {
+        val start = starts(index)
+        val first = in.buf(start).toInt
+        if (first != CONSTANT_FIELDREF &&
+            first != CONSTANT_METHODREF &&
+            first != CONSTANT_INTFMETHODREF) errorBadTag(start)
+        val ownerTpe = getClassOrArrayType(in.getChar(start + 1).toInt)
+        debuglog("getMemberSymbol(static: " + static + "): owner type: " + ownerTpe + " " + ownerTpe.typeSymbol.originalName)
+        val (name0, tpe0) = getNameAndType(in.getChar(start + 3).toInt, ownerTpe)
+        debuglog("getMemberSymbol: name and tpe: " + name0 + ": " + tpe0)
+
+        forceMangledName(tpe0.typeSymbol.name, module = false)
+        val (name, tpe) = getNameAndType(in.getChar(start + 3).toInt, ownerTpe)
+        if (name == nme.MODULE_INSTANCE_FIELD) {
+          val index = in.getChar(start + 1).toInt
+          val name = getExternalName(in.getChar(starts(index).toInt + 1).toInt)
+          //assert(name.endsWith("$"), "Not a module class: " + name)
+          f = forceMangledName(name dropRight 1, module = true)
+          if (f == NoSymbol)
+            f = rootMirror.getModuleByName(name dropRight 1)
+        } else {
+          val origName = nme.unexpandedName(name)
+          val owner = if (static) ownerTpe.typeSymbol.linkedClassOfClass else ownerTpe.typeSymbol
+          f = owner.info.findMember(origName, 0, 0, stableOnly = false).suchThat(_.tpe.widen =:= tpe)
+          if (f == NoSymbol)
+            f = owner.info.findMember(newTermName(origName + nme.LOCAL_SUFFIX_STRING), 0, 0, stableOnly = false).suchThat(_.tpe =:= tpe)
+          if (f == NoSymbol) {
+            // if it's an impl class, try to find it's static member inside the class
+            if (ownerTpe.typeSymbol.isImplClass) {
+              f = ownerTpe.findMember(origName, 0, 0, stableOnly = false).suchThat(_.tpe =:= tpe)
+            } else {
+              log("Couldn't find " + name + ": " + tpe + " inside: \n" + ownerTpe)
+              f = tpe match {
+                case MethodType(_, _) => owner.newMethod(name.toTermName, owner.pos)
+                case _                => owner.newVariable(name.toTermName, owner.pos)
+              }
+              f setInfo tpe
+              log("created fake member " + f.fullName)
+            }
+          }
+        }
+        assert(f != NoSymbol,
+          s"could not find $name: $tpe in $ownerTpe" + (
+            if (settings.debug.value) ownerTpe.members.mkString(", members are:\n  ", "\n  ", "") else ""
+          )
+        )
+        values(index) = f
+      }
+      f
+    }
+  }
+
   /** Read back bytecode for the given class symbol. It returns
    *  two IClass objects, one for static members and one
    *  for non-static members.
