Cleanups for tracing in GenBCode, improve some comments

4 files changed, 17 insertions, 11 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala b/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala
index 856f85d9e3..2af2037fec 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala
@@ -8,6 +8,7 @@ package scala.tools.nsc.backend.jvm
 import scala.tools.asm.tree.{ClassNode, MethodNode}
 import java.io.PrintWriter
 import scala.tools.asm.util.{TraceClassVisitor, TraceMethodVisitor, Textifier}
+import scala.tools.asm.ClassReader
 
 object AsmUtils {
 
@@ -50,4 +51,11 @@ object AsmUtils {
     w.flush()
   }
 
+  def traceClass(bytes: Array[Byte]): Unit = traceClass(readClass(bytes))
+
+  def readClass(bytes: Array[Byte]): ClassNode = {
+    val node = new ClassNode()
+    new ClassReader(bytes).accept(node, 0)
+    node
+  }
 }
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
index 13a5c6413d..988c04f514 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
@@ -1401,7 +1401,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM {
 
       // TODO param names: (m.params map (p => javaName(p.sym)))
 
-      // typestate: entering mode with valid call sequences:
+      // typestate: entering mode with valid call sequences: (see ASM Guide, 3.2.1)
       //   [ visitAnnotationDefault ] ( visitAnnotation | visitParameterAnnotation | visitAttribute )*
 
       emitAnnotations(jmethod, others)
@@ -1446,7 +1446,10 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM {
         val hasStaticBitSet = ((flags & asm.Opcodes.ACC_STATIC) != 0)
         genCode(m, emitVars, hasStaticBitSet)
 
-        jmethod.visitMaxs(0, 0) // just to follow protocol, dummy arguments
+        // visitMaxs needs to be called according to the protocol. The arguments will be ignored
+        // since maximums (and stack map frames) are computed. See ASM Guide, Section 3.2.1,
+        // section "ClassWriter options"
+        jmethod.visitMaxs(0, 0)
       }
 
       jmethod.visitEnd()
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala
index 61cf76f524..9b292fee7f 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala
@@ -244,14 +244,9 @@ abstract class GenBCode extends BCodeSyncAndTry {
         val beanC   = if (bean == null)   null else SubItem3(bean.name, getByteArray(bean))
 
         if (AsmUtils.traceSerializedClassEnabled && plain.name.contains(AsmUtils.traceSerializedClassPattern)) {
-          def readClass(bytes: Array[Byte]): asm.tree.ClassNode = {
-            val node = new asm.tree.ClassNode()
-            new asm.ClassReader(bytes).accept(node, 0)
-            node
-          }
-          if (mirrorC != null) AsmUtils.traceClass(readClass(mirrorC.jclassBytes))
-          AsmUtils.traceClass(readClass(plainC.jclassBytes))
-          if (beanC != null) AsmUtils.traceClass(readClass(beanC.jclassBytes))
+          if (mirrorC != null) AsmUtils.traceClass(mirrorC.jclassBytes)
+          AsmUtils.traceClass(plainC.jclassBytes)
+          if (beanC != null) AsmUtils.traceClass(beanC.jclassBytes)
         }
 
         q3 add Item3(arrivalPos, mirrorC, plainC, beanC, outFolder)
diff --git a/src/compiler/scala/tools/nsc/transform/Mixin.scala b/src/compiler/scala/tools/nsc/transform/Mixin.scala
index 33e8e47c76..3ef85728da 100644
--- a/src/compiler/scala/tools/nsc/transform/Mixin.scala
+++ b/src/compiler/scala/tools/nsc/transform/Mixin.scala
@@ -391,7 +391,7 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL {
           else {
             sourceModule setPos sym.pos
             if (sourceModule.flags != MODULE) {
-              log("!!! Directly setting sourceModule flags from %s to MODULE".format(sourceModule.flagString))
+              log("!!! Directly setting sourceModule flags for $sourceModule from %s to MODULE".format(sourceModule.flagString))
               sourceModule.flags = MODULE
             }
           }