diff options
12 files changed, 534 insertions, 52 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeBodyBuilder.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeBodyBuilder.scala index 062daa4eac..1b3f124dd8 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/BCodeBodyBuilder.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeBodyBuilder.scala @@ -12,6 +12,7 @@ package jvm import scala.annotation.switch import scala.tools.asm +import GenBCode._ /* * @@ -613,7 +614,7 @@ abstract class BCodeBodyBuilder extends BCodeSkelBuilder { */ for (i <- args.length until dims) elemKind = ArrayBType(elemKind) } - (argsSize : @switch) match { + argsSize match { case 1 => bc newarray elemKind case _ => val descr = ('[' * argsSize) + elemKind.descriptor // denotes the same as: arrayN(elemKind, argsSize).descriptor diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeHelpers.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeHelpers.scala index ccee230191..e366bbabb8 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/BCodeHelpers.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeHelpers.scala @@ -10,6 +10,7 @@ package backend.jvm import scala.tools.asm import scala.collection.mutable import scala.tools.nsc.io.AbstractFile +import GenBCode._ /* * Traits encapsulating functionality to convert Scala AST Trees into ASM ClassNodes. diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeIdiomatic.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeIdiomatic.scala index c3db28151b..c743ebd16f 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/BCodeIdiomatic.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeIdiomatic.scala @@ -10,6 +10,7 @@ package backend.jvm import scala.tools.asm import scala.annotation.switch import scala.collection.mutable +import GenBCode._ /* * A high-level facade to the ASM API for bytecode generation. @@ -42,9 +43,6 @@ abstract class BCodeIdiomatic extends SubComponent { val StringBuilderClassName = "scala/collection/mutable/StringBuilder" - val CLASS_CONSTRUCTOR_NAME = "<clinit>" - val INSTANCE_CONSTRUCTOR_NAME = "<init>" - val EMPTY_STRING_ARRAY = Array.empty[String] val EMPTY_INT_ARRAY = Array.empty[Int] val EMPTY_LABEL_ARRAY = Array.empty[asm.Label] diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeSkelBuilder.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeSkelBuilder.scala index 142c901c21..48df4e1121 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/BCodeSkelBuilder.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeSkelBuilder.scala @@ -16,6 +16,7 @@ import scala.annotation.switch import scala.tools.asm import scala.tools.asm.util.{TraceMethodVisitor, ASMifier} import java.io.PrintWriter +import GenBCode._ /* * diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala b/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala index ff30631c10..fe4c4794a9 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala @@ -11,6 +11,7 @@ import scala.tools.asm import asm.Opcodes import scala.tools.asm.tree.{InnerClassNode, ClassNode} import opt.{ByteCodeRepository, Inliner} +import OptimizerReporting._ import scala.collection.convert.decorateAsScala._ /** @@ -273,7 +274,7 @@ abstract class BTypes { ObjectReference case _: MethodBType => - throw new AssertionError(s"unexpected method type when computing maxType: $this") + assertionError(s"unexpected method type when computing maxType: $this") } /** @@ -364,7 +365,7 @@ abstract class BTypes { */ final def maxValueType(other: BType): BType = { - def uncomparable: Nothing = throw new AssertionError(s"Cannot compute maxValueType: $this, $other") + def uncomparable: Nothing = assertionError(s"Cannot compute maxValueType: $this, $other") if (!other.isPrimitive && !other.isNothingType) uncomparable diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala index d5e95c47cf..9b3bd7648d 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/GenBCode.scala @@ -410,4 +410,7 @@ object GenBCode { 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 + + val CLASS_CONSTRUCTOR_NAME = "<clinit>" + val INSTANCE_CONSTRUCTOR_NAME = "<init>" } diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/ByteCodeRepository.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/ByteCodeRepository.scala index 9e56f25888..b3ac06877b 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/opt/ByteCodeRepository.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/ByteCodeRepository.scala @@ -13,6 +13,7 @@ import scala.collection.convert.decorateAsScala._ import scala.tools.nsc.io.AbstractFile import scala.tools.nsc.util.ClassFileLookup import OptimizerReporting._ +import BytecodeUtils._ import ByteCodeRepository._ import BTypes.InternalName @@ -93,16 +94,6 @@ class ByteCodeRepository(val classPath: ClassFileLookup[AbstractFile], val class inlineFailure(s"Class file for class $fullName not found.") } } - - private def removeLineNumberNodes(classNode: ClassNode): Unit = { - for (method <- classNode.methods.asScala) { - val iter = method.instructions.iterator() - while (iter.hasNext) iter.next() match { - case _: LineNumberNode => iter.remove() - case _ => - } - } - } } object ByteCodeRepository { diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/BytecodeUtils.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/BytecodeUtils.scala index 6b4047c0a7..4cff92d38b 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/opt/BytecodeUtils.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/BytecodeUtils.scala @@ -10,9 +10,14 @@ package opt import scala.annotation.{tailrec, switch} import scala.collection.mutable import scala.reflect.internal.util.Collections._ -import scala.tools.asm.Opcodes +import scala.tools.asm.tree.analysis._ +import scala.tools.asm.{MethodWriter, ClassWriter, Label, Opcodes} import scala.tools.asm.tree._ import scala.collection.convert.decorateAsScala._ +import GenBCode._ +import scala.collection.convert.decorateAsScala._ +import scala.collection.convert.decorateAsJava._ +import scala.tools.nsc.backend.jvm.BTypes._ object BytecodeUtils { @@ -68,6 +73,16 @@ object BytecodeUtils { def isExecutable(instruction: AbstractInsnNode): Boolean = instruction.getOpcode >= 0 + def isConstructor(methodNode: MethodNode): Boolean = { + methodNode.name == INSTANCE_CONSTRUCTOR_NAME || methodNode.name == CLASS_CONSTRUCTOR_NAME + } + + def isStaticMethod(methodNode: MethodNode): Boolean = (methodNode.access & Opcodes.ACC_STATIC) != 0 + + def isAbstractMethod(methodNode: MethodNode): Boolean = (methodNode.access & Opcodes.ACC_ABSTRACT) != 0 + + def isSynchronizedMethod(methodNode: MethodNode): Boolean = (methodNode.access & Opcodes.ACC_SYNCHRONIZED) != 0 + def nextExecutableInstruction(instruction: AbstractInsnNode, alsoKeep: AbstractInsnNode => Boolean = Set()): Option[AbstractInsnNode] = { var result = instruction do { result = result.getNext } @@ -181,4 +196,112 @@ object BytecodeUtils { if (handler.end == from) handler.end = to } } + + /** + * In order to run an Analyzer, the maxLocals / maxStack fields need to be available. The ASM + * framework only computes these values during bytecode generation. + * + * Since there's currently no better way, we run a bytecode generator on the method and extract + * the computed values. This required changes to the ASM codebase: + * - the [[MethodWriter]] class was made public + * - accessors for maxLocals / maxStack were added to the MethodWriter class + * + * We could probably make this faster (and allocate less memory) by hacking the ASM framework + * more: create a subclass of MethodWriter with a /dev/null byteVector. Another option would be + * to create a separate visitor for computing those values, duplicating the functionality from the + * MethodWriter. + */ + def computeMaxLocalsMaxStack(method: MethodNode) { + val cw = new ClassWriter(ClassWriter.COMPUTE_MAXS) + val excs = method.exceptions.asScala.toArray + val mw = cw.visitMethod(method.access, method.name, method.desc, method.signature, excs).asInstanceOf[MethodWriter] + method.accept(mw) + method.maxLocals = mw.getMaxLocals + method.maxStack = mw.getMaxStack + } + + def removeLineNumberNodes(classNode: ClassNode): Unit = { + for (m <- classNode.methods.asScala) removeLineNumberNodes(m.instructions) + } + + def removeLineNumberNodes(instructions: InsnList): Unit = { + val iter = instructions.iterator() + while (iter.hasNext) iter.next() match { + case _: LineNumberNode => iter.remove() + case _ => + } + } + + def cloneLabels(methodNode: MethodNode): Map[LabelNode, LabelNode] = { + methodNode.instructions.iterator().asScala.collect({ + case labelNode: LabelNode => (labelNode, newLabelNode) + }).toMap + } + + /** + * Create a new [[LabelNode]] with a correctly associated [[Label]]. + */ + def newLabelNode: LabelNode = { + val label = new Label + val labelNode = new LabelNode(label) + label.info = labelNode + labelNode + } + + /** + * Clone the instructions in `methodNode` into a new [[InsnList]], mapping labels according to + * the `labelMap`. Returns the new instruction list and a map from old to new instructions. + */ + def cloneInstructions(methodNode: MethodNode, labelMap: Map[LabelNode, LabelNode]): (InsnList, Map[AbstractInsnNode, AbstractInsnNode]) = { + val javaLabelMap = labelMap.asJava + val result = new InsnList + var map = Map.empty[AbstractInsnNode, AbstractInsnNode] + for (ins <- methodNode.instructions.iterator.asScala) { + val cloned = ins.clone(javaLabelMap) + result add cloned + map += ((ins, cloned)) + } + (result, map) + } + + /** + * Clone the local variable descriptors of `methodNode` and map their `start` and `end` labels + * according to the `labelMap`. + */ + def cloneLocalVariableNodes(methodNode: MethodNode, labelMap: Map[LabelNode, LabelNode], prefix: String): List[LocalVariableNode] = { + methodNode.localVariables.iterator().asScala.map(localVariable => new LocalVariableNode( + prefix + localVariable.name, + localVariable.desc, + localVariable.signature, + labelMap(localVariable.start), + labelMap(localVariable.end), + localVariable.index + )).toList + } + + /** + * Clone the local try/catch blocks of `methodNode` and map their `start` and `end` and `handler` + * labels according to the `labelMap`. + */ + def cloneTryCatchBlockNodes(methodNode: MethodNode, labelMap: Map[LabelNode, LabelNode]): List[TryCatchBlockNode] = { + methodNode.tryCatchBlocks.iterator().asScala.map(tryCatch => new TryCatchBlockNode( + labelMap(tryCatch.start), + labelMap(tryCatch.end), + labelMap(tryCatch.handler), + tryCatch.`type` + )).toList + } + + class BasicAnalyzer(methodNode: MethodNode, classInternalName: InternalName) { + val analyzer = new Analyzer[BasicValue](new BasicInterpreter) + analyzer.analyze(classInternalName, methodNode) + def frameAt(instruction: AbstractInsnNode): Frame[BasicValue] = analyzer.getFrames()(methodNode.instructions.indexOf(instruction)) + } + + implicit class `frame extensions`[V <: Value](val frame: Frame[V]) extends AnyVal { + def peekDown(n: Int): V = { + val topIndex = frame.getStackSize - 1 + frame.getStack(topIndex - n) + } + } } diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala index 6e5e03f730..f964b5b25d 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala @@ -8,15 +8,206 @@ package backend.jvm package opt import scala.tools.asm -import asm.Opcodes +import asm.Opcodes._ import asm.tree._ import scala.collection.convert.decorateAsScala._ +import scala.collection.convert.decorateAsJava._ +import AsmUtils._ +import BytecodeUtils._ import OptimizerReporting._ +import scala.tools.asm.tree.analysis._ class Inliner[BT <: BTypes](val btypes: BT) { import btypes._ import btypes.byteCodeRepository + /** + * Copy and adapt the instructions of a method to a callsite. + * + * Preconditions: + * - The maxLocals and maxStack values of the callsite method are correctly computed + * - The callsite method contains no unreachable basic blocks, i.e., running an [[Analyzer]] + * does not produce any `null` frames + * + * @param callsiteInstruction The invocation instruction + * @param callsiteStackHeight The stack height at the callsite + * @param callsiteMethod The method in which the invocation occurs + * @param callsiteClass The class in which the callsite method is defined + * @param callee The invoked method + * @param calleeDeclarationClass The class in which the invoked method is defined + * @param receiverKnownNotNull `true` if the receiver is known to be non-null + * @param keepLineNumbers `true` if LineNumberNodes should be copied to the call site + * @return `Some(message)` if inlining cannot be performed, `None` otherwise + */ + def inline(callsiteInstruction: MethodInsnNode, callsiteStackHeight: Int, callsiteMethod: MethodNode, callsiteClass: ClassBType, + callee: MethodNode, calleeDeclarationClass: ClassBType, + receiverKnownNotNull: Boolean, keepLineNumbers: Boolean): Option[String] = { + canInline(callsiteInstruction, callsiteStackHeight, callsiteMethod, callsiteClass, callee, calleeDeclarationClass) orElse { + // New labels for the cloned instructions + val labelsMap = cloneLabels(callee) + val (clonedInstructions, instructionMap) = cloneInstructions(callee, labelsMap) + if (!keepLineNumbers) { + removeLineNumberNodes(clonedInstructions) + } + + // local vars in the callee are shifted by the number of locals at the callsite + val localVarShift = callsiteMethod.maxLocals + clonedInstructions.iterator.asScala foreach { + case varInstruction: VarInsnNode => varInstruction.`var` += localVarShift + case _ => () + } + + // add a STORE instruction for each expected argument, including for THIS instance if any + val argStores = new InsnList + var nextLocalIndex = callsiteMethod.maxLocals + if (!isStaticMethod(callee)) { + if (!receiverKnownNotNull) { + argStores.add(new InsnNode(DUP)) + val nonNullLabel = newLabelNode + argStores.add(new JumpInsnNode(IFNONNULL, nonNullLabel)) + argStores.add(new InsnNode(ACONST_NULL)) + argStores.add(new InsnNode(ATHROW)) + argStores.add(nonNullLabel) + } + argStores.add(new VarInsnNode(ASTORE, nextLocalIndex)) + nextLocalIndex += 1 + } + + // We just use an asm.Type here, no need to create the MethodBType. + val calleAsmType = asm.Type.getMethodType(callee.desc) + + for(argTp <- calleAsmType.getArgumentTypes) { + val opc = argTp.getOpcode(ISTORE) // returns the correct xSTORE instruction for argTp + argStores.insert(new VarInsnNode(opc, nextLocalIndex)) // "insert" is "prepend" - the last argument is on the top of the stack + nextLocalIndex += argTp.getSize + } + + clonedInstructions.insert(argStores) + + // label for the exit of the inlined functions. xRETURNs are rplaced by GOTOs to this label. + val postCallLabel = newLabelNode + clonedInstructions.add(postCallLabel) + + // replace xRETURNs: + // - store the return value (if any) + // - clear the stack of the inlined method (insert DROPs) + // - load the return value + // - GOTO postCallLabel + + val returnType = calleAsmType.getReturnType + val hasReturnValue = returnType.getSort != asm.Type.VOID + val returnValueIndex = callsiteMethod.maxLocals + callee.maxLocals + nextLocalIndex += returnType.getSize + + def returnValueStore(returnInstruction: AbstractInsnNode) = { + val opc = returnInstruction.getOpcode match { + case IRETURN => ISTORE + case LRETURN => LSTORE + case FRETURN => FSTORE + case DRETURN => DSTORE + case ARETURN => ASTORE + } + new VarInsnNode(opc, returnValueIndex) + } + + // We run an interpreter to know the stack height at each xRETURN instruction and the sizes + // of the values on the stack. + val analyzer = new BasicAnalyzer(callee, calleeDeclarationClass.internalName) + + for (originalReturn <- callee.instructions.iterator().asScala if isReturn(originalReturn)) { + val frame = analyzer.frameAt(originalReturn) + var stackHeight = frame.getStackSize + + val inlinedReturn = instructionMap(originalReturn) + val returnReplacement = new InsnList + + def drop(slot: Int) = returnReplacement add getPop(frame.peekDown(slot).getSize) + + // for non-void methods, store the stack top into the return local variable + if (hasReturnValue) { + returnReplacement add returnValueStore(originalReturn) + stackHeight -= 1 + } + + // drop the rest of the stack + for (i <- 0 until stackHeight) drop(i) + + returnReplacement add new JumpInsnNode(GOTO, postCallLabel) + clonedInstructions.insert(inlinedReturn, returnReplacement) + clonedInstructions.remove(inlinedReturn) + } + + // Load instruction for the return value + if (hasReturnValue) { + val retVarLoad = { + val opc = returnType.getOpcode(ILOAD) + new VarInsnNode(opc, returnValueIndex) + } + clonedInstructions.insert(postCallLabel, retVarLoad) + } + + callsiteMethod.instructions.insert(callsiteInstruction, clonedInstructions) + callsiteMethod.instructions.remove(callsiteInstruction) + + callsiteMethod.localVariables.addAll(cloneLocalVariableNodes(callee, labelsMap, callee.name + "_").asJava) + callsiteMethod.tryCatchBlocks.addAll(cloneTryCatchBlockNodes(callee, labelsMap).asJava) + + callsiteMethod.maxLocals += returnType.getSize + callee.maxLocals + callsiteMethod.maxStack = math.max(callsiteMethod.maxStack, callee.maxStack + callsiteStackHeight) + + None + } + } + + /** + * Check whether an inling can be performed. Parmeters are described in method [[inline]]. + * @return `Some(message)` if inlining cannot be performed, `None` otherwise + */ + def canInline(callsiteInstruction: MethodInsnNode, callsiteStackHeight: Int, callsiteMethod: MethodNode, callsiteClass: ClassBType, + callee: MethodNode, calleeDeclarationClass: ClassBType): Option[String] = { + + def calleeDesc = s"${callee.name} of type ${callee.desc} in ${calleeDeclarationClass.internalName}" + def methodMismatch = s"Wrong method node for inlining ${textify(callsiteInstruction)}: $calleeDesc" + assert(callsiteInstruction.name == callee.name, methodMismatch) + assert(callsiteInstruction.desc == callee.desc, methodMismatch) + assert(!isConstructor(callee), s"Constructors cannot be inlined: $calleeDesc") + assert(!BytecodeUtils.isAbstractMethod(callee), s"Callee is abstract: $calleeDesc") + assert(callsiteMethod.instructions.contains(callsiteInstruction), s"Callsite ${textify(callsiteInstruction)} is not an instruction of $calleeDesc") + + // When an exception is thrown, the stack is cleared before jumping to the handler. When + // inlining a method that catches an exception, all values that were on the stack before the + // call (in addition to the arguments) would be cleared (SI-6157). So we don't inline methods + // with handlers in case there are values on the stack. + // Alternatively, we could save all stack values below the method arguments into locals, but + // that would be inefficient: we'd need to pop all parameters, save the values, and push the + // parameters back for the (inlined) invocation. Similarly for the result after the call. + def stackHasNonParameters: Boolean = { + val expectedArgs = asm.Type.getArgumentTypes(callsiteInstruction.desc).length + (callsiteInstruction.getOpcode match { + case INVOKEVIRTUAL | INVOKESPECIAL | INVOKEINTERFACE => 1 + case INVOKESTATIC => 0 + case INVOKEDYNAMIC => + assertionError(s"Unexpected opcode, cannot inline ${textify(callsiteInstruction)}") + }) + callsiteStackHeight > expectedArgs + } + + if (isSynchronizedMethod(callee)) { + // Could be done by locking on the receiver, wrapping the inlined code in a try and unlocking + // in finally. But it's probably not worth the effort, scala never emits synchronized methods. + Some(s"Method ${methodSignature(calleeDeclarationClass.internalName, callee)} is not inlined because it is synchronized") + } else if (!callee.tryCatchBlocks.isEmpty && stackHasNonParameters) { + Some( + s"""The operand stack at the callsite in ${methodSignature(callsiteClass.internalName, callsiteMethod)} contains more values than the + |arguments expected by the callee ${methodSignature(calleeDeclarationClass.internalName, callee)}. These values would be discarded + |when entering an exception handler declared in the inlined method.""".stripMargin + ) + } else findIllegalAccess(callee.instructions, callsiteClass) map { + case illegalAccessIns => + s"""The callee ${methodSignature(calleeDeclarationClass.internalName, callee)} contains the instruction ${AsmUtils.textify(illegalAccessIns)} + |that would cause an IllegalAccessError when inlined into class ${callsiteClass.internalName}""".stripMargin + } + } + def findIllegalAccess(instructions: InsnList, destinationClass: ClassBType): Option[AbstractInsnNode] = { /** @@ -57,14 +248,14 @@ class Inliner[BT <: BTypes](val btypes: BT) { // TODO: B3 requires "same run-time package", which seems to be package + classloader (JMVS 5.3.). is the below ok? def samePackageAsDestination = memberDeclClass.packageInternalName == destinationClass.packageInternalName - val key = (Opcodes.ACC_PUBLIC | Opcodes.ACC_PROTECTED | Opcodes.ACC_PRIVATE) & memberFlags + val key = (ACC_PUBLIC | ACC_PROTECTED | ACC_PRIVATE) & memberFlags key match { - case Opcodes.ACC_PUBLIC => // B1 + case ACC_PUBLIC => // B1 true - case Opcodes.ACC_PROTECTED => // B2 + case ACC_PROTECTED => // B2 val condB2 = destinationClass.isSubtypeOf(memberDeclClass) && { - val isStatic = (Opcodes.ACC_STATIC & memberFlags) != 0 + val isStatic = (ACC_STATIC & memberFlags) != 0 isStatic || memberRefClass.isSubtypeOf(destinationClass) || destinationClass.isSubtypeOf(memberRefClass) } condB2 || samePackageAsDestination // B3 (protected) @@ -72,7 +263,7 @@ class Inliner[BT <: BTypes](val btypes: BT) { case 0 => // B3 (default access) samePackageAsDestination - case Opcodes.ACC_PRIVATE => // B4 + case ACC_PRIVATE => // B4 memberDeclClass == destinationClass } } diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/LocalOpt.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/LocalOpt.scala index 87ad715e4d..3a7250031a 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/opt/LocalOpt.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/LocalOpt.scala @@ -8,7 +8,7 @@ package backend.jvm package opt import scala.annotation.switch -import scala.tools.asm.{Opcodes, MethodWriter, ClassWriter} +import scala.tools.asm.Opcodes import scala.tools.asm.tree.analysis.{Analyzer, BasicValue, BasicInterpreter} import scala.tools.asm.tree._ import scala.collection.convert.decorateAsScala._ @@ -73,7 +73,7 @@ class LocalOpt(settings: ScalaSettings) { * * Returns `true` if the bytecode of `method` was changed. */ - private def methodOptimizations(method: MethodNode, ownerClassName: String): Boolean = { + def methodOptimizations(method: MethodNode, ownerClassName: String): Boolean = { if (method.instructions.size == 0) return false // fast path for abstract methods // unreachable-code also removes unused local variable nodes and empty exception handlers. @@ -319,29 +319,6 @@ class LocalOpt(settings: ScalaSettings) { } /** - * In order to run an Analyzer, the maxLocals / maxStack fields need to be available. The ASM - * framework only computes these values during bytecode generation. - * - * Since there's currently no better way, we run a bytecode generator on the method and extract - * the computed values. This required changes to the ASM codebase: - * - the [[MethodWriter]] class was made public - * - accessors for maxLocals / maxStack were added to the MethodWriter class - * - * We could probably make this faster (and allocate less memory) by hacking the ASM framework - * more: create a subclass of MethodWriter with a /dev/null byteVector. Another option would be - * to create a separate visitor for computing those values, duplicating the functionality from the - * MethodWriter. - */ - private def computeMaxLocalsMaxStack(method: MethodNode) { - val cw = new ClassWriter(ClassWriter.COMPUTE_MAXS) - val excs = method.exceptions.asScala.toArray - val mw = cw.visitMethod(method.access, method.name, method.desc, method.signature, excs).asInstanceOf[MethodWriter] - method.accept(mw) - method.maxLocals = mw.getMaxLocals - method.maxStack = mw.getMaxStack - } - - /** * Removes LineNumberNodes that don't describe any executable instructions. * * This method expects (and asserts) that the `start` label of each LineNumberNode is the diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/OptimizerReporting.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/OptimizerReporting.scala index 7002e43d98..a918e13534 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/opt/OptimizerReporting.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/OptimizerReporting.scala @@ -8,17 +8,19 @@ package backend.jvm import scala.tools.asm import asm.tree._ +import scala.tools.nsc.backend.jvm.BTypes.InternalName /** * Reporting utilities used in the optimizer. + * + * TODO: move out of opt package, rename: it's already used outside the optimizer. + * Centralize backend reporting here. */ object OptimizerReporting { - def methodSignature(className: String, methodName: String, methodDescriptor: String): String = { - className + "::" + methodName + methodDescriptor + def methodSignature(classInternalName: InternalName, method: MethodNode): String = { + classInternalName + "::" + method.name + method.desc } - def methodSignature(className: String, method: MethodNode): String = methodSignature(className, method.name, method.desc) - def inlineFailure(reason: String): Nothing = MissingRequirementError.signal(reason) def assertionError(message: String): Nothing = throw new AssertionError(message) } diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/InlinerTest.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/InlinerTest.scala new file mode 100644 index 0000000000..1aa7bd1391 --- /dev/null +++ b/test/junit/scala/tools/nsc/backend/jvm/opt/InlinerTest.scala @@ -0,0 +1,193 @@ +package scala.tools.nsc +package backend.jvm +package opt + +import org.junit.runner.RunWith +import org.junit.runners.JUnit4 +import org.junit.Test +import scala.tools.asm.Opcodes._ +import org.junit.Assert._ + +import scala.tools.asm.tree._ +import scala.tools.asm.tree.analysis._ +import scala.tools.nsc.backend.jvm.opt.BytecodeUtils.BasicAnalyzer +import scala.tools.testing.AssertUtil._ + +import CodeGenTools._ +import scala.tools.partest.ASMConverters +import ASMConverters._ +import AsmUtils._ + +import scala.collection.convert.decorateAsScala._ + +@RunWith(classOf[JUnit4]) +class InlinerTest { + val compiler = newCompiler(extraArgs = "-Ybackend:GenBCode -Yopt:l:none") + import compiler.genBCode.bTypes._ + def addToRepo(cls: List[ClassNode]): List[ClassNode] = { + for (c <- cls) byteCodeRepository.classes(c.name) = (c, ByteCodeRepository.Classfile) + cls + } + + // inline first invocation of f into g in class C + def inlineTest(code: String, mod: ClassNode => Unit = _ => ()): (MethodNode, Option[String]) = { + val List(cls) = addToRepo(compileClasses(compiler)(code)) + mod(cls) + val clsBType = classBTypeFromParsedClassfile(cls.name) + + val List(f, g) = cls.methods.asScala.filter(m => Set("f", "g")(m.name)).toList.sortBy(_.name) + val fCall = g.instructions.iterator.asScala.collect({ case i: MethodInsnNode if i.name == "f" => i }).next() + + val analyzer = new BasicAnalyzer(g, clsBType.internalName) + + val r = inliner.inline( + fCall, + analyzer.frameAt(fCall).getStackSize, + g, + clsBType, + f, + clsBType, + receiverKnownNotNull = true, + keepLineNumbers = true) + (g, r) + } + + @Test + def simpleInlineOK(): Unit = { + val code = + """class C { + | def f = 1 + | def g = f + f + |} + """.stripMargin + + val (g, _) = inlineTest(code) + + val gConv = convertMethod(g) + assertSameCode(gConv.instructions.dropNonOp, + List( + VarOp(ALOAD, 0), VarOp(ASTORE, 1), // store this + Op(ICONST_1), VarOp(ISTORE, 2), Jump(GOTO, Label(10)), // store return value + Label(10), VarOp(ILOAD, 2), // load return value + VarOp(ALOAD, 0), Invoke(INVOKEVIRTUAL, "C", "f", "()I", false), Op(IADD), Op(IRETURN))) + + // line numbers are kept, so there's a line 2 (from the inlined f) + assert(gConv.instructions exists { + case LineNumber(2, _) => true + case _ => false + }, gConv.instructions.filter(_.isInstanceOf[LineNumber])) + + assert(gConv.localVars.map(_.name).sorted == List("f_this", "this"), gConv.localVars) + assert(g.maxStack == 2 && g.maxLocals == 3, s"${g.maxLocals} - ${g.maxStack}") + } + + @Test + def nothingTypedOK(): Unit = { + val code = + """class C { + | def f: Nothing = ??? + | def g: Int = { f; 1 } + |} + """.stripMargin + + // On the bytecode level, methods of type Nothing have return type Nothing$. + // This can be treated like any other result object. + + // See also discussion around ATHROW in BCodeBodyBuilder + + val (g, _) = inlineTest(code) + val expectedInlined = List( + VarOp(ALOAD, 0), VarOp(ASTORE, 1), // store this + Field(GETSTATIC, "scala/Predef$", "MODULE$", "Lscala/Predef$;"), Invoke(INVOKEVIRTUAL, "scala/Predef$", "$qmark$qmark$qmark", "()Lscala/runtime/Nothing$;", false)) // inlined call to ??? + + assertSameCode(convertMethod(g).instructions.dropNonOp.take(4), expectedInlined) + + localOpt.methodOptimizations(g, "C") + assertSameCode(convertMethod(g).instructions.dropNonOp, + expectedInlined ++ List(VarOp(ASTORE, 2), VarOp(ALOAD, 2), Op(ATHROW))) + } + + @Test + def synchronizedNoInline(): Unit = { + val code = + """class C { + | def f: Int = 0 + | def g: Int = f + |} + """.stripMargin + + val (_, can) = inlineTest(code, cls => { + val f = cls.methods.asScala.find(_.name == "f").get + f.access |= ACC_SYNCHRONIZED + }) + assert(can.get contains "synchronized", can) + } + + @Test + def tryCatchOK(): Unit = { + val code = + """class C { + | def f: Int = try { 1 } catch { case _: Exception => 2 } + | def g = f + 1 + |} + """.stripMargin + val (_, r) = inlineTest(code) + assert(r.isEmpty, r) + } + + @Test + def tryCatchNoInline(): Unit = { + // cannot inline f: there's a value on g's stack. if f throws and enters the handler, all values + // on the stack are removed, including the one of g's stack that we still need. + val code = + """class C { + | def f: Int = try { 1 } catch { case _: Exception => 2 } + | def g = println(f) + |} + """.stripMargin + val (_, r) = inlineTest(code) + assert(r.get contains "operand stack at the callsite", r) + } + + @Test + def illegalAccessNoInline(): Unit = { + val code = + """package a { + | class C { + | private def f: Int = 0 + | def g: Int = f + | } + |} + |package b { + | class D { + | def h(c: a.C): Int = c.g + 1 + | } + |} + """.stripMargin + + val List(c, d) = addToRepo(compileClasses(compiler)(code)) + + val cTp = classBTypeFromParsedClassfile(c.name) + val dTp = classBTypeFromParsedClassfile(d.name) + + val g = c.methods.asScala.find(_.name == "g").get + val h = d.methods.asScala.find(_.name == "h").get + val gCall = h.instructions.iterator.asScala.collect({ + case m: MethodInsnNode if m.name == "g" => m + }).next() + + val analyzer = new BasicAnalyzer(h, dTp.internalName) + + val r = inliner.inline( + gCall, + analyzer.frameAt(gCall).getStackSize, + h, + dTp, + g, + cTp, + receiverKnownNotNull = true, + keepLineNumbers = true) + + assert(r.get contains "would cause an IllegalAccessError", r) + } +} |