Remove Tracked, add type information to ClassBType

Before this change, a ClassBType was just a name. The `exemplars` map
stored a Tracked instance for every ClassBType. Tracked stored
type information that is required later in the backend when things
may run concurrently. In particular: superclass, interfaces, flags
and information for emitting the InnerClass attribute. Now we put all
the information stored in Tracked directly in the ClassBType.

There is still one hash map: `classBTypeFromInternalNameMap` maps
a JVM internal class name (e.g. "scala/Predef$") to the corresponding
ClassBType. This map is used during bytecode generation, when the
ASM framework computes stack map frames.

In order to compute stack map frames, the ASM framework needs to be
able to get the LUB of two types. The default implementation uses
reflection to get type information, however that doesn't work in our
case: the classes we compile are not on the classpath. So instead,
the backend overwrites the method `getCommonSuperClass` of the
ClassWriter. This method receives two class internal names and
computes their LUB. This is done by looking up the ClassBTypes in the
`classBTypeFromInternalNameMap` and invoking `jvmWiseLUB`.

This commit was reviwed in https://github.com/scala/scala/pull/3855.
It consists of all commits labelled [squash-after-review], squashed
into one.

1 files changed, 10 insertions, 4 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala
index 5494a827f4..480767f407 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala
@@ -46,6 +46,8 @@ import scala.tools.asm
 abstract class GenBCode extends BCodeSyncAndTry {
   import global._
 
+  import bTypes._
+
   val phaseName = "jvm"
 
   override def newPhase(prev: Phase) = new BCodePhase(prev)
@@ -272,7 +274,7 @@ abstract class GenBCode extends BCodeSyncAndTry {
 
       arrivalPos = 0 // just in case
       scalaPrimitives.init()
-      initBCodeTypes()
+      bTypes.intializeCoreBTypes()
 
       // initBytecodeWriter invokes fullName, thus we have to run it before the typer-dependent thread is activated.
       bytecodeWriter  = initBytecodeWriter(cleanup.getEntryPoints)
@@ -297,9 +299,6 @@ abstract class GenBCode extends BCodeSyncAndTry {
        * (2) if requested, check-java-signatures, over and beyond the syntactic checks in `getGenericSignature()`
        *
        */
-
-      // clearing maps
-      clearBCodeTypes()
     }
 
     /*
@@ -385,3 +384,10 @@ abstract class GenBCode extends BCodeSyncAndTry {
   } // end of class BCodePhase
 
 } // end of class GenBCode
+
+object GenBCode {
+  def mkFlags(args: Int*) = args.foldLeft(0)(_ | _)
+
+  final val PublicStatic      = asm.Opcodes.ACC_PUBLIC | asm.Opcodes.ACC_STATIC
+  final val PublicStaticFinal = asm.Opcodes.ACC_PUBLIC | asm.Opcodes.ACC_STATIC | asm.Opcodes.ACC_FINAL
+}