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Diffstat (limited to 'src/compiler/scala/tools/nsc/backend/jvm/analysis/BackendUtils.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/backend/jvm/analysis/BackendUtils.scala | 514 |
1 files changed, 514 insertions, 0 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/analysis/BackendUtils.scala b/src/compiler/scala/tools/nsc/backend/jvm/analysis/BackendUtils.scala new file mode 100644 index 0000000000..90da570f01 --- /dev/null +++ b/src/compiler/scala/tools/nsc/backend/jvm/analysis/BackendUtils.scala @@ -0,0 +1,514 @@ +package scala.tools.nsc +package backend.jvm +package analysis + +import java.lang.invoke.LambdaMetafactory + +import scala.annotation.switch +import scala.collection.JavaConverters._ +import scala.collection.mutable +import scala.tools.asm.Opcodes._ +import scala.tools.asm.tree._ +import scala.tools.asm.tree.analysis._ +import scala.tools.asm.{Handle, Type} +import scala.tools.nsc.backend.jvm.BTypes._ +import scala.tools.nsc.backend.jvm.GenBCode._ +import scala.tools.nsc.backend.jvm.opt.BytecodeUtils._ + +/** + * This component hosts tools and utilities used in the backend that require access to a `BTypes` + * instance. + * + * One example is the AsmAnalyzer class, which runs `computeMaxLocalsMaxStack` on the methodNode to + * be analyzed. This method in turn lives inside the BTypes assembly because it queries the per-run + * cache `maxLocalsMaxStackComputed` defined in there. + */ +class BackendUtils[BT <: BTypes](val btypes: BT) { + import btypes._ + import btypes.coreBTypes._ + import callGraph.ClosureInstantiation + + /** + * A wrapper to make ASM's Analyzer a bit easier to use. + */ + class AsmAnalyzer[V <: Value](methodNode: MethodNode, classInternalName: InternalName, val analyzer: Analyzer[V] = new Analyzer(new BasicInterpreter)) { + computeMaxLocalsMaxStack(methodNode) + try { + analyzer.analyze(classInternalName, methodNode) + } catch { + case ae: AnalyzerException => + throw new AnalyzerException(null, "While processing " + classInternalName + "." + methodNode.name, ae) + } + def frameAt(instruction: AbstractInsnNode): Frame[V] = analyzer.frameAt(instruction, methodNode) + } + + /** + * See the doc comment on package object `analysis` for a discussion on performance. + */ + object AsmAnalyzer { + // jvm limit is 65535 for both number of instructions and number of locals + + private def size(method: MethodNode) = method.instructions.size.toLong * method.maxLocals * method.maxLocals + + // with the limits below, analysis should not take more than one second + + private val nullnessSizeLimit = 5000l * 600l * 600l // 5000 insns, 600 locals + private val basicValueSizeLimit = 9000l * 1000l * 1000l + private val sourceValueSizeLimit = 8000l * 950l * 950l + + def sizeOKForAliasing(method: MethodNode): Boolean = size(method) < nullnessSizeLimit + def sizeOKForNullness(method: MethodNode): Boolean = size(method) < nullnessSizeLimit + def sizeOKForBasicValue(method: MethodNode): Boolean = size(method) < basicValueSizeLimit + def sizeOKForSourceValue(method: MethodNode): Boolean = size(method) < sourceValueSizeLimit + } + + class ProdConsAnalyzer(val methodNode: MethodNode, classInternalName: InternalName) extends AsmAnalyzer(methodNode, classInternalName, new Analyzer(new InitialProducerSourceInterpreter)) with ProdConsAnalyzerImpl + + class NonLubbingTypeFlowAnalyzer(val methodNode: MethodNode, classInternalName: InternalName) extends AsmAnalyzer(methodNode, classInternalName, new Analyzer(new NonLubbingTypeFlowInterpreter)) + + /** + * Add: + * private static Object $deserializeLambda$(SerializedLambda l) { + * return indy[scala.runtime.LambdaDeserialize.bootstrap](l) + * } + * + * We use invokedynamic here to enable caching within the deserializer without needing to + * host a static field in the enclosing class. This allows us to add this method to interfaces + * that define lambdas in default methods. + */ + def addLambdaDeserialize(classNode: ClassNode, implMethods: Iterable[Handle]): Unit = { + val cw = classNode + + // Make sure to reference the ClassBTypes of all types that are used in the code generated + // here (e.g. java/util/Map) are initialized. Initializing a ClassBType adds it to the + // `classBTypeFromInternalName` map. When writing the classfile, the asm ClassWriter computes + // stack map frames and invokes the `getCommonSuperClass` method. This method expects all + // ClassBTypes mentioned in the source code to exist in the map. + + val nilLookupDesc = MethodBType(Nil, jliMethodHandlesLookupRef).descriptor + val serlamObjDesc = MethodBType(jliSerializedLambdaRef :: Nil, ObjectRef).descriptor + + { + val mv = cw.visitMethod(ACC_PRIVATE + ACC_STATIC + ACC_SYNTHETIC, "$deserializeLambda$", serlamObjDesc, null, null) + mv.visitCode() + mv.visitVarInsn(ALOAD, 0) + mv.visitInvokeDynamicInsn("lambdaDeserialize", serlamObjDesc, lambdaDeserializeBootstrapHandle, implMethods.toArray: _*) + mv.visitInsn(ARETURN) + mv.visitEnd() + } + } + + /** + * 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, and + * a list of lambda implementation methods references by invokedynamic[LambdaMetafactory] for a + * serializable SAM types. + */ + def cloneInstructions(methodNode: MethodNode, labelMap: Map[LabelNode, LabelNode], keepLineNumbers: Boolean): (InsnList, Map[AbstractInsnNode, AbstractInsnNode], List[Handle]) = { + val javaLabelMap = labelMap.asJava + val result = new InsnList + var map = Map.empty[AbstractInsnNode, AbstractInsnNode] + var inlinedTargetHandles = mutable.ListBuffer[Handle]() + for (ins <- methodNode.instructions.iterator.asScala) { + ins match { + case callGraph.LambdaMetaFactoryCall(indy, _, _, _) => indy.bsmArgs match { + case Array(_, targetHandle: Handle, _, flags: Integer, xs@_*) if (flags.intValue & LambdaMetafactory.FLAG_SERIALIZABLE) != 0 => + inlinedTargetHandles += targetHandle + case _ => + } + case _ => + } + if (keepLineNumbers || !ins.isInstanceOf[LineNumberNode]) { + val cloned = ins.clone(javaLabelMap) + result add cloned + map += ((ins, cloned)) + } + } + (result, map, inlinedTargetHandles.toList) + } + + def getBoxedUnit: FieldInsnNode = new FieldInsnNode(GETSTATIC, srBoxedUnitRef.internalName, "UNIT", srBoxedUnitRef.descriptor) + + private val anonfunAdaptedName = """.*\$anonfun\$.*\$\d+\$adapted""".r + def hasAdaptedImplMethod(closureInit: ClosureInstantiation): Boolean = { + anonfunAdaptedName.pattern.matcher(closureInit.lambdaMetaFactoryCall.implMethod.getName).matches + } + + private def primitiveAsmTypeToBType(primitiveType: Type): PrimitiveBType = (primitiveType.getSort: @switch) match { + case Type.BOOLEAN => BOOL + case Type.BYTE => BYTE + case Type.CHAR => CHAR + case Type.SHORT => SHORT + case Type.INT => INT + case Type.LONG => LONG + case Type.FLOAT => FLOAT + case Type.DOUBLE => DOUBLE + case _ => null + } + + def isScalaBox(insn: MethodInsnNode): Boolean = { + insn.owner == srBoxesRunTimeRef.internalName && { + val args = Type.getArgumentTypes(insn.desc) + args.length == 1 && (srBoxesRuntimeBoxToMethods.get(primitiveAsmTypeToBType(args(0))) match { + case Some(MethodNameAndType(name, tp)) => name == insn.name && tp.descriptor == insn.desc + case _ => false + }) + } + } + + def getScalaBox(primitiveType: Type): MethodInsnNode = { + val bType = primitiveAsmTypeToBType(primitiveType) + val MethodNameAndType(name, methodBType) = srBoxesRuntimeBoxToMethods(bType) + new MethodInsnNode(INVOKESTATIC, srBoxesRunTimeRef.internalName, name, methodBType.descriptor, /*itf =*/ false) + } + + def isScalaUnbox(insn: MethodInsnNode): Boolean = { + insn.owner == srBoxesRunTimeRef.internalName && (srBoxesRuntimeUnboxToMethods.get(primitiveAsmTypeToBType(Type.getReturnType(insn.desc))) match { + case Some(MethodNameAndType(name, tp)) => name == insn.name && tp.descriptor == insn.desc + case _ => false + }) + } + + def getScalaUnbox(primitiveType: Type): MethodInsnNode = { + val bType = primitiveAsmTypeToBType(primitiveType) + val MethodNameAndType(name, methodBType) = srBoxesRuntimeUnboxToMethods(bType) + new MethodInsnNode(INVOKESTATIC, srBoxesRunTimeRef.internalName, name, methodBType.descriptor, /*itf =*/ false) + } + + private def calleeInMap(insn: MethodInsnNode, map: Map[InternalName, MethodNameAndType]): Boolean = map.get(insn.owner) match { + case Some(MethodNameAndType(name, tp)) => insn.name == name && insn.desc == tp.descriptor + case _ => false + } + + def isJavaBox(insn: MethodInsnNode): Boolean = calleeInMap(insn, javaBoxMethods) + def isJavaUnbox(insn: MethodInsnNode): Boolean = calleeInMap(insn, javaUnboxMethods) + + def isPredefAutoBox(insn: MethodInsnNode): Boolean = { + insn.owner == PredefRef.internalName && (predefAutoBoxMethods.get(insn.name) match { + case Some(tp) => insn.desc == tp.descriptor + case _ => false + }) + } + + def isPredefAutoUnbox(insn: MethodInsnNode): Boolean = { + insn.owner == PredefRef.internalName && (predefAutoUnboxMethods.get(insn.name) match { + case Some(tp) => insn.desc == tp.descriptor + case _ => false + }) + } + + def isRefCreate(insn: MethodInsnNode): Boolean = calleeInMap(insn, srRefCreateMethods) + def isRefZero(insn: MethodInsnNode): Boolean = calleeInMap(insn, srRefZeroMethods) + + def runtimeRefClassBoxedType(refClass: InternalName): Type = Type.getArgumentTypes(srRefCreateMethods(refClass).methodType.descriptor)(0) + + def isSideEffectFreeCall(insn: MethodInsnNode): Boolean = { + isScalaBox(insn) || isScalaUnbox(insn) || + isJavaBox(insn) || // not java unbox, it may NPE + isSideEffectFreeConstructorCall(insn) + } + + def isNonNullMethodInvocation(mi: MethodInsnNode): Boolean = { + isJavaBox(mi) || isScalaBox(mi) || isPredefAutoBox(mi) || isRefCreate(mi) || isRefZero(mi) + } + + def isModuleLoad(insn: AbstractInsnNode, moduleName: InternalName): Boolean = insn match { + case fi: FieldInsnNode => fi.getOpcode == GETSTATIC && fi.owner == moduleName && fi.name == "MODULE$" && fi.desc == ("L" + moduleName + ";") + case _ => false + } + + def isPredefLoad(insn: AbstractInsnNode) = isModuleLoad(insn, PredefRef.internalName) + + def isPrimitiveBoxConstructor(insn: MethodInsnNode): Boolean = calleeInMap(insn, primitiveBoxConstructors) + def isRuntimeRefConstructor(insn: MethodInsnNode): Boolean = calleeInMap(insn, srRefConstructors) + def isTupleConstructor(insn: MethodInsnNode): Boolean = calleeInMap(insn, tupleClassConstructors) + + // unused objects created by these constructors are eliminated by pushPop + private lazy val sideEffectFreeConstructors: Set[(String, String)] = { + val ownerDesc = (p: (InternalName, MethodNameAndType)) => (p._1, p._2.methodType.descriptor) + primitiveBoxConstructors.map(ownerDesc).toSet ++ + srRefConstructors.map(ownerDesc) ++ + tupleClassConstructors.map(ownerDesc) ++ Set( + (ObjectRef.internalName, MethodBType(Nil, UNIT).descriptor), + (StringRef.internalName, MethodBType(Nil, UNIT).descriptor), + (StringRef.internalName, MethodBType(List(StringRef), UNIT).descriptor), + (StringRef.internalName, MethodBType(List(ArrayBType(CHAR)), UNIT).descriptor)) + } + + def isSideEffectFreeConstructorCall(insn: MethodInsnNode): Boolean = { + insn.name == INSTANCE_CONSTRUCTOR_NAME && sideEffectFreeConstructors((insn.owner, insn.desc)) + } + + private lazy val classesOfSideEffectFreeConstructors = sideEffectFreeConstructors.map(_._1) + + def isNewForSideEffectFreeConstructor(insn: AbstractInsnNode) = { + insn.getOpcode == NEW && { + val ti = insn.asInstanceOf[TypeInsnNode] + classesOfSideEffectFreeConstructors.contains(ti.desc) + } + } + + def isBoxedUnit(insn: AbstractInsnNode) = { + insn.getOpcode == GETSTATIC && { + val fi = insn.asInstanceOf[FieldInsnNode] + fi.owner == srBoxedUnitRef.internalName && fi.name == "UNIT" && fi.desc == srBoxedUnitRef.descriptor + } + } + + /** + * Visit the class node and collect all referenced nested classes. + */ + def collectNestedClasses(classNode: ClassNode): List[ClassBType] = { + val innerClasses = mutable.Set.empty[ClassBType] + + def visitInternalName(internalName: InternalName): Unit = if (internalName != null) { + val t = classBTypeFromParsedClassfile(internalName) + if (t.isNestedClass.get) innerClasses += t + } + + // either an internal/Name or [[Linternal/Name; -- there are certain references in classfiles + // that are either an internal name (without the surrounding `L;`) or an array descriptor + // `[Linternal/Name;`. + def visitInternalNameOrArrayReference(ref: String): Unit = if (ref != null) { + val bracket = ref.lastIndexOf('[') + if (bracket == -1) visitInternalName(ref) + else if (ref.charAt(bracket + 1) == 'L') visitInternalName(ref.substring(bracket + 2, ref.length - 1)) + } + + // we are only interested in the class references in the descriptor, so we can skip over + // primitives and the brackets of array descriptors + def visitDescriptor(desc: String): Unit = (desc.charAt(0): @switch) match { + case '(' => + val internalNames = mutable.ListBuffer.empty[String] + var i = 1 + while (i < desc.length) { + if (desc.charAt(i) == 'L') { + val start = i + 1 // skip the L + while (desc.charAt(i) != ';') i += 1 + internalNames append desc.substring(start, i) + } + // skips over '[', ')', primitives + i += 1 + } + internalNames foreach visitInternalName + + case 'L' => + visitInternalName(desc.substring(1, desc.length - 1)) + + case '[' => + visitInternalNameOrArrayReference(desc) + + case _ => // skip over primitive types + } + + def visitConstant(const: AnyRef): Unit = const match { + case t: Type => visitDescriptor(t.getDescriptor) + case _ => + } + + // in principle we could references to annotation types, as they only end up as strings in the + // constant pool, not as class references. however, the java compiler still includes nested + // annotation classes in the innerClass table, so we do the same. explained in detail in the + // large comment in class BTypes. + def visitAnnotation(annot: AnnotationNode): Unit = { + visitDescriptor(annot.desc) + if (annot.values != null) annot.values.asScala foreach visitConstant + } + + def visitAnnotations(annots: java.util.List[_ <: AnnotationNode]) = if (annots != null) annots.asScala foreach visitAnnotation + def visitAnnotationss(annotss: Array[java.util.List[AnnotationNode]]) = if (annotss != null) annotss foreach visitAnnotations + + def visitHandle(handle: Handle): Unit = { + visitInternalNameOrArrayReference(handle.getOwner) + visitDescriptor(handle.getDesc) + } + + visitInternalName(classNode.name) + innerClasses ++= classBTypeFromParsedClassfile(classNode.name).info.get.nestedClasses + + visitInternalName(classNode.superName) + classNode.interfaces.asScala foreach visitInternalName + visitInternalName(classNode.outerClass) + + visitAnnotations(classNode.visibleAnnotations) + visitAnnotations(classNode.visibleTypeAnnotations) + visitAnnotations(classNode.invisibleAnnotations) + visitAnnotations(classNode.invisibleTypeAnnotations) + + for (f <- classNode.fields.asScala) { + visitDescriptor(f.desc) + visitAnnotations(f.visibleAnnotations) + visitAnnotations(f.visibleTypeAnnotations) + visitAnnotations(f.invisibleAnnotations) + visitAnnotations(f.invisibleTypeAnnotations) + } + + for (m <- classNode.methods.asScala) { + visitDescriptor(m.desc) + + visitAnnotations(m.visibleAnnotations) + visitAnnotations(m.visibleTypeAnnotations) + visitAnnotations(m.invisibleAnnotations) + visitAnnotations(m.invisibleTypeAnnotations) + visitAnnotationss(m.visibleParameterAnnotations) + visitAnnotationss(m.invisibleParameterAnnotations) + visitAnnotations(m.visibleLocalVariableAnnotations) + visitAnnotations(m.invisibleLocalVariableAnnotations) + + m.exceptions.asScala foreach visitInternalName + for (tcb <- m.tryCatchBlocks.asScala) visitInternalName(tcb.`type`) + + val iter = m.instructions.iterator() + while (iter.hasNext) iter.next() match { + case ti: TypeInsnNode => visitInternalNameOrArrayReference(ti.desc) + case fi: FieldInsnNode => visitInternalNameOrArrayReference(fi.owner); visitDescriptor(fi.desc) + case mi: MethodInsnNode => visitInternalNameOrArrayReference(mi.owner); visitDescriptor(mi.desc) + case id: InvokeDynamicInsnNode => visitDescriptor(id.desc); visitHandle(id.bsm); id.bsmArgs foreach visitConstant + case ci: LdcInsnNode => visitConstant(ci.cst) + case ma: MultiANewArrayInsnNode => visitDescriptor(ma.desc) + case _ => + } + } + innerClasses.toList + } + + /** + * In order to run an Analyzer, the maxLocals / maxStack fields need to be available. The ASM + * framework only computes these values during bytecode generation. + * + * NOTE 1: as explained in the `analysis` package object, the maxStack value used by the Analyzer + * may be smaller than the correct maxStack value in the classfile (Analyzers only use a single + * slot for long / double values). The maxStack computed here are correct for running an analyzer, + * but not for writing in the classfile. We let the ClassWriter recompute max's. + * + * NOTE 2: the maxStack value computed here may be larger than the smallest correct value + * that would allow running an analyzer, see `InstructionStackEffect.forAsmAnalysis` and + * `InstructionStackEffect.maxStackGrowth`. + * + * NOTE 3: the implementation doesn't look at instructions that cannot be reached, it computes + * the max local / stack size in the reachable code. These max's work just fine for running an + * Analyzer: its implementation also skips over unreachable code in the same way. + */ + def computeMaxLocalsMaxStack(method: MethodNode): Unit = { + if (isAbstractMethod(method) || isNativeMethod(method)) { + method.maxLocals = 0 + method.maxStack = 0 + } else if (!maxLocalsMaxStackComputed(method)) { + val size = method.instructions.size + + var maxLocals = parametersSize(method) + var maxStack = 0 + + // queue of instruction indices where analysis should start + var queue = new Array[Int](8) + var top = -1 + def enq(i: Int): Unit = { + if (top == queue.length - 1) { + val nq = new Array[Int](queue.length * 2) + Array.copy(queue, 0, nq, 0, queue.length) + queue = nq + } + top += 1 + queue(top) = i + } + def deq(): Int = { + val r = queue(top) + top -= 1 + r + } + + val subroutineRetTargets = new mutable.Stack[AbstractInsnNode] + + // for each instruction in the queue, contains the stack height at this instruction. + // once an instruction has been treated, contains -1 to prevent re-enqueuing + val stackHeights = new Array[Int](size) + + def enqInsn(insn: AbstractInsnNode, height: Int): Unit = { + enqInsnIndex(method.instructions.indexOf(insn), height) + } + + def enqInsnIndex(insnIndex: Int, height: Int): Unit = { + if (insnIndex < size && stackHeights(insnIndex) != -1) { + stackHeights(insnIndex) = height + enq(insnIndex) + } + } + + val tcbIt = method.tryCatchBlocks.iterator() + while (tcbIt.hasNext) { + val tcb = tcbIt.next() + enqInsn(tcb.handler, 1) + if (maxStack == 0) maxStack = 1 + } + + enq(0) + while (top != -1) { + val insnIndex = deq() + val insn = method.instructions.get(insnIndex) + val initHeight = stackHeights(insnIndex) + stackHeights(insnIndex) = -1 // prevent i from being enqueued again + + if (insn.getOpcode == -1) { // frames, labels, line numbers + enqInsnIndex(insnIndex + 1, initHeight) + } else { + val stackGrowth = InstructionStackEffect.maxStackGrowth(insn) + val heightAfter = initHeight + stackGrowth + if (heightAfter > maxStack) maxStack = heightAfter + + // update maxLocals + insn match { + case v: VarInsnNode => + val longSize = if (isSize2LoadOrStore(v.getOpcode)) 1 else 0 + maxLocals = math.max(maxLocals, v.`var` + longSize + 1) // + 1 because local numbers are 0-based + + case i: IincInsnNode => + maxLocals = math.max(maxLocals, i.`var` + 1) + + case _ => + } + + insn match { + case j: JumpInsnNode => + if (j.getOpcode == JSR) { + val jsrTargetHeight = heightAfter + 1 + if (jsrTargetHeight > maxStack) maxStack = jsrTargetHeight + subroutineRetTargets.push(j.getNext) + enqInsn(j.label, jsrTargetHeight) + } else { + enqInsn(j.label, heightAfter) + val opc = j.getOpcode + if (opc != GOTO) enqInsnIndex(insnIndex + 1, heightAfter) // jump is conditional, so the successor is also a possible control flow target + } + + case l: LookupSwitchInsnNode => + var j = 0 + while (j < l.labels.size) { + enqInsn(l.labels.get(j), heightAfter); j += 1 + } + enqInsn(l.dflt, heightAfter) + + case t: TableSwitchInsnNode => + var j = 0 + while (j < t.labels.size) { + enqInsn(t.labels.get(j), heightAfter); j += 1 + } + enqInsn(t.dflt, heightAfter) + + case r: VarInsnNode if r.getOpcode == RET => + enqInsn(subroutineRetTargets.pop(), heightAfter) + + case _ => + val opc = insn.getOpcode + if (opc != ATHROW && !isReturn(insn)) + enqInsnIndex(insnIndex + 1, heightAfter) + } + } + } + + method.maxLocals = maxLocals + method.maxStack = maxStack + + maxLocalsMaxStackComputed += method + } + } +} |