GenASM: pipeline disk-write with building of classfiles

Author: magarciaEPFL

src/compiler/scala/tools/nsc/backend/jvm/BytecodeWriters.scala

@@ -37,7 +37,7 @@ trait BytecodeWriters {
     getFile(outputDirectory(sym), clsName, suffix)
 
   trait BytecodeWriter {
-    def writeClass(label: String, jclassName: String, jclassBytes: Array[Byte], sym: Symbol): Unit
+    def writeClass(label: String, jclassName: String, jclassBytes: Array[Byte], outfile: AbstractFile): Unit
     def close(): Unit = ()
   }
 
@@ -48,7 +48,9 @@ trait BytecodeWriters {
     )
     val writer = new Jar(jfile).jarWriter(jarMainAttrs: _*)
 
-    def writeClass(label: String, jclassName: String, jclassBytes: Array[Byte], sym: Symbol) {
+    def writeClass(label: String, jclassName: String, jclassBytes: Array[Byte], outfile: AbstractFile) {
+      assert(outfile == null,
+             "The outfile formal param is there just because ClassBytecodeWriter overrides this method and uses it.")
       val path = jclassName + ".class"
       val out  = writer.newOutputStream(path)
 
@@ -72,21 +74,21 @@ trait BytecodeWriters {
       try javap(Seq("-verbose", "dummy")) foreach (_.show())
       finally pw.close()
     }
-    abstract override def writeClass(label: String, jclassName: String, jclassBytes: Array[Byte], sym: Symbol) {
-      super.writeClass(label, jclassName, jclassBytes, sym)
+    abstract override def writeClass(label: String, jclassName: String, jclassBytes: Array[Byte], outfile: AbstractFile) {
+      super.writeClass(label, jclassName, jclassBytes, outfile)
 
-      val bytes     = getFile(sym, jclassName, ".class").toByteArray
       val segments  = jclassName.split("[./]")
       val javapFile = segments.foldLeft(baseDir: Path)(_ / _) changeExtension "javap" toFile;
 
       javapFile.parent.createDirectory()
-      emitJavap(bytes, javapFile)
+      emitJavap(jclassBytes, javapFile)
     }
   }
 
   trait ClassBytecodeWriter extends BytecodeWriter {
-    def writeClass(label: String, jclassName: String, jclassBytes: Array[Byte], sym: Symbol) {
-      val outfile   = getFile(sym, jclassName, ".class")
+    def writeClass(label: String, jclassName: String, jclassBytes: Array[Byte], outfile: AbstractFile) {
+      assert(outfile != null,
+             "Precisely this override requires its invoker to hand out a non-null AbstractFile.")
       val outstream = new DataOutputStream(outfile.bufferedOutput)
 
       try outstream.write(jclassBytes, 0, jclassBytes.length)
@@ -98,8 +100,8 @@ trait BytecodeWriters {
   trait DumpBytecodeWriter extends BytecodeWriter {
     val baseDir = Directory(settings.Ydumpclasses.value).createDirectory()
 
-    abstract override def writeClass(label: String, jclassName: String, jclassBytes: Array[Byte], sym: Symbol) {
-      super.writeClass(label, jclassName, jclassBytes, sym)
+    abstract override def writeClass(label: String, jclassName: String, jclassBytes: Array[Byte], outfile: AbstractFile) {
+      super.writeClass(label, jclassName, jclassBytes, outfile)
 
       val pathName = jclassName
       var dumpFile = pathName.split("[./]").foldLeft(baseDir: Path) (_ / _) changeExtension "class" toFile;

src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala

@@ -29,6 +29,10 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
 
   val phaseName = "jvm"
 
+  case class WorkUnit(label: String, jclassName: String, jclass: asm.ClassWriter, outF: AbstractFile)
+
+  type WorkUnitQueue = _root_.java.util.concurrent.LinkedBlockingQueue[WorkUnit]
+
   /** Create a new phase */
   override def newPhase(p: Phase): Phase = new AsmPhase(p)
 
@@ -148,6 +152,44 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
       }
     }
 
+    // -----------------------------------------------------------------------------------------
+    // Allow overlapping disk write of classfiles with building of the next classfiles.
+    // -----------------------------------------------------------------------------------------
+
+    val q = new WorkUnitQueue(500)
+
+    class WriteTask(bytecodeWriter: BytecodeWriter) extends _root_.java.lang.Runnable {
+
+      def run() {
+        var stop = false
+        try {
+          while (!stop) {
+            val WorkUnit(label, jclassName, jclass, outF) = q.take
+            if(jclass eq null) { stop = true }
+            else { writeIfNotTooBig(label, jclassName, jclass, outF) }
+          }
+        } catch {
+          case ex: InterruptedException => throw ex
+        }
+      }
+
+      private def writeIfNotTooBig(label: String, jclassName: String, jclass: asm.ClassWriter, outF: AbstractFile) {
+        try {
+          val arr = jclass.toByteArray()
+          bytecodeWriter.writeClass(label, jclassName, arr, outF)
+        } catch {
+          case e: java.lang.RuntimeException if(e.getMessage() == "Class file too large!") =>
+            // TODO check where ASM throws the equivalent of CodeSizeTooBigException
+            log("Skipped class "+jclassName+" because it exceeds JVM limits (it's too big or has methods that are too long).")
+        }
+      }
+
+    }
+
+    // -----------------------------------------------------------------------------------------
+    // what AsmPhase does.
+    // -----------------------------------------------------------------------------------------
+
     override def run() {
 
       if (settings.debug.value)
@@ -161,10 +203,14 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
       var sortedClasses = classes.values.toList sortBy ("" + _.symbol.fullName)
 
       debuglog("Created new bytecode generator for " + classes.size + " classes.")
-      val bytecodeWriter  = initBytecodeWriter(sortedClasses filter isJavaEntryPoint)
-      val plainCodeGen    = new JPlainBuilder(bytecodeWriter)
-      val mirrorCodeGen   = new JMirrorBuilder(bytecodeWriter)
-      val beanInfoCodeGen = new JBeanInfoBuilder(bytecodeWriter)
+      val bytecodeWriter        = initBytecodeWriter(sortedClasses filter isJavaEntryPoint)
+      val needsOutfileForSymbol = bytecodeWriter.isInstanceOf[ClassBytecodeWriter]
+
+      val plainCodeGen    = new JPlainBuilder(q, needsOutfileForSymbol)
+      val mirrorCodeGen   = new JMirrorBuilder(q, needsOutfileForSymbol)
+      val beanInfoCodeGen = new JBeanInfoBuilder(q, needsOutfileForSymbol)
+
+      new _root_.java.lang.Thread(new WriteTask(bytecodeWriter)).start()
 
       while(!sortedClasses.isEmpty) {
         val c = sortedClasses.head
@@ -187,6 +233,10 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
         classes -= c.symbol // GC opportunity
       }
 
+      q put WorkUnit(null, null, null, null)
+
+      while(!q.isEmpty) { _root_.java.lang.Thread.sleep(10) }
+
       bytecodeWriter.close()
       classes.clear()
       reverseJavaName.clear()
@@ -448,7 +498,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
   val JAVA_LANG_STRING = asm.Type.getObjectType("java/lang/String")
 
   /** basic functionality for class file building */
-  abstract class JBuilder(bytecodeWriter: BytecodeWriter) {
+  abstract class JBuilder(wuQ: WorkUnitQueue, needsOutfileForSymbol: Boolean) {
 
     val EMPTY_JTYPE_ARRAY  = Array.empty[asm.Type]
     val EMPTY_STRING_ARRAY = Array.empty[String]
@@ -504,17 +554,6 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
     // utitilies useful when emitting plain, mirror, and beaninfo classes.
     // -----------------------------------------------------------------------------------------
 
-    def writeIfNotTooBig(label: String, jclassName: String, jclass: asm.ClassWriter, sym: Symbol) {
-      try {
-        val arr = jclass.toByteArray()
-        bytecodeWriter.writeClass(label, jclassName, arr, sym)
-      } catch {
-        case e: java.lang.RuntimeException if(e.getMessage() == "Class file too large!") =>
-          // TODO check where ASM throws the equivalent of CodeSizeTooBigException
-          log("Skipped class "+jclassName+" because it exceeds JVM limits (it's too big or has methods that are too long).")
-      }
-    }
-
     /** Specialized array conversion to prevent calling
      *  java.lang.reflect.Array.newInstance via TraversableOnce.toArray
      */
@@ -728,11 +767,18 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
       }
     }
 
+    def enqueue(label: String, jclassName: String, jclass: asm.ClassWriter, sym: Symbol) {
+      val outF: scala.tools.nsc.io.AbstractFile = {
+        if(needsOutfileForSymbol) getFile(sym, jclassName, ".class") else null
+      }
+      wuQ put WorkUnit(label, jclassName, jclass, outF)
+    }
+
   } // end of class JBuilder
 
 
   /** functionality for building plain and mirror classes */
-  abstract class JCommonBuilder(bytecodeWriter: BytecodeWriter) extends JBuilder(bytecodeWriter) {
+  abstract class JCommonBuilder(wuQ: WorkUnitQueue, needsOutfileForSymbol: Boolean) extends JBuilder(wuQ, needsOutfileForSymbol) {
 
     // -----------------------------------------------------------------------------------------
     // more constants
@@ -1290,8 +1336,8 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
   case class BlockInteval(start: BasicBlock, end: BasicBlock)
 
   /** builder of plain classes */
-  class JPlainBuilder(bytecodeWriter: BytecodeWriter)
-    extends JCommonBuilder(bytecodeWriter)
+  class JPlainBuilder(wuQ: WorkUnitQueue, needsOutfileForSymbol: Boolean)
+    extends JCommonBuilder(wuQ, needsOutfileForSymbol)
     with    JAndroidBuilder {
 
     val MIN_SWITCH_DENSITY = 0.7
@@ -1445,7 +1491,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
 
       addInnerClasses(clasz.symbol, jclass)
       jclass.visitEnd()
-      writeIfNotTooBig("" + c.symbol.name, thisName, jclass, c.symbol)
+      enqueue("" + c.symbol.name, thisName, jclass, c.symbol)
 
     }
 
@@ -2863,7 +2909,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
 
 
   /** builder of mirror classes */
-  class JMirrorBuilder(bytecodeWriter: BytecodeWriter) extends JCommonBuilder(bytecodeWriter) {
+  class JMirrorBuilder(wuQ: WorkUnitQueue, needsOutfileForSymbol: Boolean) extends JCommonBuilder(wuQ, needsOutfileForSymbol) {
 
     private var cunit: CompilationUnit = _
     def getCurrentCUnit(): CompilationUnit = cunit;
@@ -2907,15 +2953,15 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
 
       addInnerClasses(modsym, mirrorClass)
       mirrorClass.visitEnd()
-      writeIfNotTooBig("" + modsym.name, mirrorName, mirrorClass, modsym)
+      enqueue("" + modsym.name, mirrorName, mirrorClass, modsym)
     }
 
 
   } // end of class JMirrorBuilder
 
 
   /** builder of bean info classes */
-  class JBeanInfoBuilder(bytecodeWriter: BytecodeWriter) extends JBuilder(bytecodeWriter) {
+  class JBeanInfoBuilder(wuQ: WorkUnitQueue, needsOutfileForSymbol: Boolean) extends JBuilder(wuQ, needsOutfileForSymbol) {
 
     /**
      * Generate a bean info class that describes the given class.
@@ -3036,7 +3082,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters {
       addInnerClasses(clasz.symbol, beanInfoClass)
       beanInfoClass.visitEnd()
 
-      writeIfNotTooBig("BeanInfo ", beanInfoName, beanInfoClass, clasz.symbol)
+      enqueue("BeanInfo ", beanInfoName, beanInfoClass, clasz.symbol)
     }
 
   } // end of class JBeanInfoBuilder

src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala

@@ -183,7 +183,6 @@ abstract class GenJVM extends SubComponent with GenJVMUtil with GenAndroid with
   class BytecodeGenerator(bytecodeWriter: BytecodeWriter) extends BytecodeUtil {
     def this() = this(new ClassBytecodeWriter { })
     def debugLevel = settings.debuginfo.indexOfChoice
-    import bytecodeWriter.writeClass
 
     val MIN_SWITCH_DENSITY = 0.7
     val INNER_CLASSES_FLAGS =
@@ -344,6 +343,15 @@ abstract class GenJVM extends SubComponent with GenJVMUtil with GenAndroid with
       writeClass("" + sym.name, jclass.getName(), toByteArray(jclass), sym)
     }
 
+    val needsOutfileForSymbol = bytecodeWriter.isInstanceOf[ClassBytecodeWriter]
+
+    def writeClass(label: String, jclassName: String, jclassBytes: Array[Byte], sym: Symbol) {
+      val outF: scala.tools.nsc.io.AbstractFile = {
+        if(needsOutfileForSymbol) getFile(sym, jclassName, ".class") else null
+      }
+      bytecodeWriter.writeClass(label, jclassName, jclassBytes, outF)
+    }
+
     /** Returns the ScalaSignature annotation if it must be added to this class,
      *  none otherwise; furthermore, it adds to `jclass` the ScalaSig marker
      *  attribute (marking that a scala signature annotation is present) or the