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Diffstat (limited to 'src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala | 648 |
1 files changed, 648 insertions, 0 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala new file mode 100644 index 0000000000..e14e57d3ab --- /dev/null +++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala @@ -0,0 +1,648 @@ +/* NSC -- new Scala compiler + * Copyright 2005-2014 LAMP/EPFL + * @author Martin Odersky + */ + +package scala.tools.nsc +package backend.jvm +package opt + +import scala.annotation.tailrec +import scala.tools.asm +import asm.Opcodes._ +import asm.tree._ +import scala.collection.convert.decorateAsScala._ +import scala.collection.convert.decorateAsJava._ +import AsmUtils._ +import BytecodeUtils._ +import collection.mutable +import scala.tools.asm.tree.analysis.{SourceInterpreter, Analyzer} +import BackendReporting._ +import scala.tools.nsc.backend.jvm.BTypes.InternalName + +class Inliner[BT <: BTypes](val btypes: BT) { + import btypes._ + import callGraph._ + + def runInliner(): Unit = { + rewriteFinalTraitMethodInvocations() + + for (request <- collectAndOrderInlineRequests) { + val Right(callee) = request.callee // collectAndOrderInlineRequests returns callsites with a known callee + + val r = inline(request.callsiteInstruction, request.callsiteStackHeight, request.callsiteMethod, request.callsiteClass, + callee.callee, callee.calleeDeclarationClass, + receiverKnownNotNull = false, keepLineNumbers = false) + + for (warning <- r) { + if ((callee.annotatedInline && btypes.warnSettings.atInlineFailed) || warning.emitWarning(warnSettings)) { + val annotWarn = if (callee.annotatedInline) " is annotated @inline but" else "" + val msg = s"${BackendReporting.methodSignature(callee.calleeDeclarationClass.internalName, callee.callee)}$annotWarn could not be inlined:\n$warning" + backendReporting.inlinerWarning(request.callsitePosition, msg) + } + } + } + } + + /** + * Ordering for inline requests. Required to make the inliner deterministic: + * - Always remove the same request when breaking inlining cycles + * - Perform inlinings in a consistent order + */ + object callsiteOrdering extends Ordering[Callsite] { + override def compare(x: Callsite, y: Callsite): Int = { + val cls = x.callsiteClass.internalName compareTo y.callsiteClass.internalName + if (cls != 0) return cls + + val name = x.callsiteMethod.name compareTo y.callsiteMethod.name + if (name != 0) return name + + val desc = x.callsiteMethod.desc compareTo y.callsiteMethod.desc + if (desc != 0) return desc + + def pos(c: Callsite) = c.callsiteMethod.instructions.indexOf(c.callsiteInstruction) + pos(x) - pos(y) + } + } + + /** + * Select callsites from the call graph that should be inlined. The resulting list of inlining + * requests is allowed to have cycles, and the callsites can appear in any order. + */ + def selectCallsitesForInlining: List[Callsite] = { + callsites.valuesIterator.filter({ + case callsite @ Callsite(_, _, _, Right(Callee(callee, calleeDeclClass, safeToInline, _, annotatedInline, _, warning)), _, _, pos) => + val res = doInlineCallsite(callsite) + + if (!res) { + if (annotatedInline && btypes.warnSettings.atInlineFailed) { + // if the callsite is annotated @inline, we report an inline warning even if the underlying + // reason is, for example, mixed compilation (which has a separate -Yopt-warning flag). + def initMsg = s"${BackendReporting.methodSignature(calleeDeclClass.internalName, callee)} is annotated @inline but cannot be inlined" + def warnMsg = warning.map(" Possible reason:\n" + _).getOrElse("") + if (doRewriteTraitCallsite(callsite)) + backendReporting.inlinerWarning(pos, s"$initMsg: the trait method call could not be rewritten to the static implementation method." + warnMsg) + else if (!safeToInline) + backendReporting.inlinerWarning(pos, s"$initMsg: the method is not final and may be overridden." + warnMsg) + else + backendReporting.inlinerWarning(pos, s"$initMsg." + warnMsg) + } else if (warning.isDefined && warning.get.emitWarning(warnSettings)) { + // when annotatedInline is false, and there is some warning, the callsite metadata is possibly incomplete. + backendReporting.inlinerWarning(pos, s"there was a problem determining if method ${callee.name} can be inlined: \n"+ warning.get) + } + } + + res + + case Callsite(ins, _, _, Left(warning), _, _, pos) => + if (warning.emitWarning(warnSettings)) + backendReporting.inlinerWarning(pos, s"failed to determine if ${ins.name} should be inlined:\n$warning") + false + }).toList + } + + /** + * The current inlining heuristics are simple: inline calls to methods annotated @inline. + */ + def doInlineCallsite(callsite: Callsite): Boolean = callsite match { + case Callsite(_, _, _, Right(Callee(callee, calleeDeclClass, safeToInline, _, annotatedInline, _, warning)), _, _, pos) => + annotatedInline && safeToInline + + case _ => false + } + + def rewriteFinalTraitMethodInvocations(): Unit = { + // Rewriting final trait method callsites to the implementation class enables inlining. + // We cannot just iterate over the values of the `callsites` map because the rewrite changes the + // map. Therefore we first copy the values to a list. + callsites.values.toList.foreach(rewriteFinalTraitMethodInvocation) + } + + /** + * True for statically resolved trait callsites that should be rewritten to the static implementation method. + */ + def doRewriteTraitCallsite(callsite: Callsite) = callsite.callee match { + case Right(Callee(callee, calleeDeclarationClass, safeToInline, true, annotatedInline, annotatedNoInline, infoWarning)) => true + case _ => false + } + + /** + * Rewrite the INVOKEINTERFACE callsite of a final trait method invocation to INVOKESTATIC of the + * corresponding method in the implementation class. This enables inlining final trait methods. + * + * In a final trait method callsite, the callee is safeToInline and the callee method is abstract + * (the receiver type is the interface, so the method is abstract). + */ + def rewriteFinalTraitMethodInvocation(callsite: Callsite): Unit = { + if (doRewriteTraitCallsite(callsite)) { + val Right(Callee(callee, calleeDeclarationClass, _, _, annotatedInline, annotatedNoInline, infoWarning)) = callsite.callee + + val traitMethodArgumentTypes = asm.Type.getArgumentTypes(callee.desc) + + val implClassInternalName = calleeDeclarationClass.internalName + "$class" + + val selfParamTypeV: Either[OptimizerWarning, ClassBType] = calleeDeclarationClass.info.map(_.inlineInfo.traitImplClassSelfType match { + case Some(internalName) => classBTypeFromParsedClassfile(internalName) + case None => calleeDeclarationClass + }) + + def implClassMethodV(implMethodDescriptor: String): Either[OptimizerWarning, MethodNode] = { + byteCodeRepository.methodNode(implClassInternalName, callee.name, implMethodDescriptor).map(_._1) + } + + // The rewrite reading the implementation class and the implementation method from the bytecode + // repository. If either of the two fails, the rewrite is not performed. + val res = for { + selfParamType <- selfParamTypeV + implMethodDescriptor = asm.Type.getMethodDescriptor(asm.Type.getReturnType(callee.desc), selfParamType.toASMType +: traitMethodArgumentTypes: _*) + implClassMethod <- implClassMethodV(implMethodDescriptor) + implClassBType = classBTypeFromParsedClassfile(implClassInternalName) + selfTypeOk <- calleeDeclarationClass.isSubtypeOf(selfParamType) + } yield { + + // The self parameter type may be incompatible with the trait type. + // trait T { self: S => def foo = 1 } + // The $self parameter type of T$class.foo is S, which may be unrelated to T. If we re-write + // a call to T.foo to T$class.foo, we need to cast the receiver to S, otherwise we get a + // VerifyError. We run a `SourceInterpreter` to find all producer instructions of the + // receiver value and add a cast to the self type after each. + if (!selfTypeOk) { + val analyzer = new AsmAnalyzer(callsite.callsiteMethod, callsite.callsiteClass.internalName, new SourceInterpreter) + val receiverValue = analyzer.frameAt(callsite.callsiteInstruction).peekDown(traitMethodArgumentTypes.length) + for (i <- receiverValue.insns.asScala) { + val cast = new TypeInsnNode(CHECKCAST, selfParamType.internalName) + callsite.callsiteMethod.instructions.insert(i, cast) + } + } + + val newCallsiteInstruction = new MethodInsnNode(INVOKESTATIC, implClassInternalName, callee.name, implMethodDescriptor, false) + callsite.callsiteMethod.instructions.insert(callsite.callsiteInstruction, newCallsiteInstruction) + callsite.callsiteMethod.instructions.remove(callsite.callsiteInstruction) + + callGraph.callsites.remove(callsite.callsiteInstruction) + val staticCallsite = Callsite( + callsiteInstruction = newCallsiteInstruction, + callsiteMethod = callsite.callsiteMethod, + callsiteClass = callsite.callsiteClass, + callee = Right(Callee( + callee = implClassMethod, + calleeDeclarationClass = implClassBType, + safeToInline = true, + safeToRewrite = false, + annotatedInline = annotatedInline, + annotatedNoInline = annotatedNoInline, + calleeInfoWarning = infoWarning)), + argInfos = Nil, + callsiteStackHeight = callsite.callsiteStackHeight, + callsitePosition = callsite.callsitePosition + ) + callGraph.callsites(newCallsiteInstruction) = staticCallsite + } + + for (warning <- res.left) { + val Right(callee) = callsite.callee + val newCallee = callee.copy(calleeInfoWarning = Some(RewriteTraitCallToStaticImplMethodFailed(calleeDeclarationClass.internalName, callee.callee.name, callee.callee.desc, warning))) + callGraph.callsites(callsite.callsiteInstruction) = callsite.copy(callee = Right(newCallee)) + } + } + } + + /** + * Returns the callsites that can be inlined. Ensures that the returned inline request graph does + * not contain cycles. + * + * The resulting list is sorted such that the leaves of the inline request graph are on the left. + * Once these leaves are inlined, the successive elements will be leaves, etc. + */ + private def collectAndOrderInlineRequests: List[Callsite] = { + val requests = selectCallsitesForInlining + + // This map is an index to look up the inlining requests for a method. The value sets are mutable + // to allow removing elided requests (to break inlining cycles). The map itself is mutable to + // allow efficient building: requests.groupBy would build values as List[Callsite] that need to + // be transformed to mutable sets. + val inlineRequestsForMethod: mutable.Map[MethodNode, mutable.Set[Callsite]] = mutable.HashMap.empty.withDefaultValue(mutable.HashSet.empty) + for (r <- requests) inlineRequestsForMethod.getOrElseUpdate(r.callsiteMethod, mutable.HashSet.empty) += r + + /** + * Break cycles in the inline request graph by removing callsites. + * + * The list `requests` is traversed left-to-right, removing those callsites that are part of a + * cycle. Elided callsites are also removed from the `inlineRequestsForMethod` map. + */ + def breakInlineCycles(requests: List[Callsite]): List[Callsite] = { + // is there a path of inline requests from start to goal? + def isReachable(start: MethodNode, goal: MethodNode): Boolean = { + @tailrec def reachableImpl(check: List[MethodNode], visited: Set[MethodNode]): Boolean = check match { + case x :: xs => + if (x == goal) true + else if (visited(x)) reachableImpl(xs, visited) + else { + val callees = inlineRequestsForMethod(x).map(_.callee.get.callee) + reachableImpl(xs ::: callees.toList, visited + x) + } + + case Nil => + false + } + reachableImpl(List(start), Set.empty) + } + + val result = new mutable.ListBuffer[Callsite]() + // sort the inline requests to ensure that removing requests is deterministic + for (r <- requests.sorted(callsiteOrdering)) { + // is there a chain of inlining requests that would inline the callsite method into the callee? + if (isReachable(r.callee.get.callee, r.callsiteMethod)) + inlineRequestsForMethod(r.callsiteMethod) -= r + else + result += r + } + result.toList + } + + // sort the remaining inline requests such that the leaves appear first, then those requests + // that become leaves, etc. + def leavesFirst(requests: List[Callsite], visited: Set[Callsite] = Set.empty): List[Callsite] = { + if (requests.isEmpty) Nil + else { + val (leaves, others) = requests.partition(r => { + val inlineRequestsForCallee = inlineRequestsForMethod(r.callee.get.callee) + inlineRequestsForCallee.forall(visited) + }) + assert(leaves.nonEmpty, requests) + leaves ::: leavesFirst(others, visited ++ leaves) + } + } + + leavesFirst(breakInlineCycles(requests)) + } + + + /** + * 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[CannotInlineWarning] = { + 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 AsmAnalyzer(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) + + // Add all invocation instructions that were inlined to the call graph + callee.instructions.iterator().asScala foreach { + case originalCallsiteIns: MethodInsnNode => + callGraph.callsites.get(originalCallsiteIns) match { + case Some(originalCallsite) => + val newCallsiteIns = instructionMap(originalCallsiteIns).asInstanceOf[MethodInsnNode] + callGraph.callsites(newCallsiteIns) = Callsite( + callsiteInstruction = newCallsiteIns, + callsiteMethod = callsiteMethod, + callsiteClass = callsiteClass, + callee = originalCallsite.callee, + argInfos = Nil, // TODO: re-compute argInfos for new destination (once we actually compute them) + callsiteStackHeight = callsiteStackHeight + originalCallsite.callsiteStackHeight, + callsitePosition = originalCallsite.callsitePosition + ) + + case None => + } + + case _ => + } + // Remove the elided invocation from the call graph + callGraph.callsites.remove(callsiteInstruction) + + 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[CannotInlineWarning] = { + + 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(SynchronizedMethod(calleeDeclarationClass.internalName, callee.name, callee.desc)) + } else if (!callee.tryCatchBlocks.isEmpty && stackHasNonParameters) { + Some(MethodWithHandlerCalledOnNonEmptyStack( + calleeDeclarationClass.internalName, callee.name, callee.desc, + callsiteClass.internalName, callsiteMethod.name, callsiteMethod.desc)) + } else findIllegalAccess(callee.instructions, calleeDeclarationClass, callsiteClass) map { + case (illegalAccessIns, None) => + IllegalAccessInstruction( + calleeDeclarationClass.internalName, callee.name, callee.desc, + callsiteClass.internalName, illegalAccessIns) + + case (illegalAccessIns, Some(warning)) => + IllegalAccessCheckFailed( + calleeDeclarationClass.internalName, callee.name, callee.desc, + callsiteClass.internalName, illegalAccessIns, warning) + } + } + + /** + * Returns the first instruction in the `instructions` list that would cause a + * [[java.lang.IllegalAccessError]] when inlined into the `destinationClass`. + * + * If validity of some instruction could not be checked because an error occurred, the instruction + * is returned together with a warning message that describes the problem. + */ + def findIllegalAccess(instructions: InsnList, calleeDeclarationClass: ClassBType, destinationClass: ClassBType): Option[(AbstractInsnNode, Option[OptimizerWarning])] = { + + /** + * Check if a type is accessible to some class, as defined in JVMS 5.4.4. + * (A1) C is public + * (A2) C and D are members of the same run-time package + */ + def classIsAccessible(accessed: BType, from: ClassBType = destinationClass): Either[OptimizerWarning, Boolean] = (accessed: @unchecked) match { + // TODO: A2 requires "same run-time package", which seems to be package + classloader (JMVS 5.3.). is the below ok? + case c: ClassBType => c.isPublic.map(_ || c.packageInternalName == from.packageInternalName) + case a: ArrayBType => classIsAccessible(a.elementType, from) + case _: PrimitiveBType => Right(true) + } + + /** + * Check if a member reference is accessible from the [[destinationClass]], as defined in the + * JVMS 5.4.4. Note that the class name in a field / method reference is not necessarily the + * class in which the member is declared: + * + * class A { def f = 0 }; class B extends A { f } + * + * The INVOKEVIRTUAL instruction uses a method reference "B.f ()I". Therefore this method has + * two parameters: + * + * @param memberDeclClass The class in which the member is declared (A) + * @param memberRefClass The class used in the member reference (B) + * + * JVMS 5.4.4 summary: A field or method R is accessible to a class D (destinationClass) iff + * (B1) R is public + * (B2) R is protected, declared in C (memberDeclClass) and D is a subclass of C. + * If R is not static, R must contain a symbolic reference to a class T (memberRefClass), + * such that T is either a subclass of D, a superclass of D, or D itself. + * (B3) R is either protected or has default access and declared by a class in the same + * run-time package as D. + * (B4) R is private and is declared in D. + */ + def memberIsAccessible(memberFlags: Int, memberDeclClass: ClassBType, memberRefClass: ClassBType): Either[OptimizerWarning, Boolean] = { + // 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 = (ACC_PUBLIC | ACC_PROTECTED | ACC_PRIVATE) & memberFlags + key match { + case ACC_PUBLIC => // B1 + Right(true) + + case ACC_PROTECTED => // B2 + tryEither { + val condB2 = destinationClass.isSubtypeOf(memberDeclClass).orThrow && { + val isStatic = (ACC_STATIC & memberFlags) != 0 + isStatic || memberRefClass.isSubtypeOf(destinationClass).orThrow || destinationClass.isSubtypeOf(memberRefClass).orThrow + } + Right(condB2 || samePackageAsDestination) // B3 (protected) + } + + case 0 => // B3 (default access) + Right(samePackageAsDestination) + + case ACC_PRIVATE => // B4 + Right(memberDeclClass == destinationClass) + } + } + + /** + * Check if `instruction` can be transplanted to `destinationClass`. + * + * If the instruction references a class, method or field that cannot be found in the + * byteCodeRepository, it is considered as not legal. This is known to happen in mixed + * compilation: for Java classes there is no classfile that could be parsed, nor does the + * compiler generate any bytecode. + * + * Returns a warning message describing the problem if checking the legality for the instruction + * failed. + */ + def isLegal(instruction: AbstractInsnNode): Either[OptimizerWarning, Boolean] = instruction match { + case ti: TypeInsnNode => + // NEW, ANEWARRAY, CHECKCAST or INSTANCEOF. For these instructions, the reference + // "must be a symbolic reference to a class, array, or interface type" (JVMS 6), so + // it can be an internal name, or a full array descriptor. + classIsAccessible(bTypeForDescriptorOrInternalNameFromClassfile(ti.desc)) + + case ma: MultiANewArrayInsnNode => + // "a symbolic reference to a class, array, or interface type" + classIsAccessible(bTypeForDescriptorOrInternalNameFromClassfile(ma.desc)) + + case fi: FieldInsnNode => + val fieldRefClass = classBTypeFromParsedClassfile(fi.owner) + for { + (fieldNode, fieldDeclClassNode) <- byteCodeRepository.fieldNode(fieldRefClass.internalName, fi.name, fi.desc): Either[OptimizerWarning, (FieldNode, InternalName)] + fieldDeclClass = classBTypeFromParsedClassfile(fieldDeclClassNode) + res <- memberIsAccessible(fieldNode.access, fieldDeclClass, fieldRefClass) + } yield { + res + } + + case mi: MethodInsnNode => + if (mi.owner.charAt(0) == '[') Right(true) // array methods are accessible + else { + def canInlineCall(opcode: Int, methodFlags: Int, methodDeclClass: ClassBType, methodRefClass: ClassBType): Either[OptimizerWarning, Boolean] = { + opcode match { + case INVOKESPECIAL if mi.name != GenBCode.INSTANCE_CONSTRUCTOR_NAME => + // invokespecial is used for private method calls, super calls and instance constructor calls. + // private method and super calls can only be inlined into the same class. + Right(destinationClass == calleeDeclarationClass) + + case _ => // INVOKEVIRTUAL, INVOKESTATIC, INVOKEINTERFACE and INVOKESPECIAL of constructors + memberIsAccessible(methodFlags, methodDeclClass, methodRefClass) + } + } + + val methodRefClass = classBTypeFromParsedClassfile(mi.owner) + for { + (methodNode, methodDeclClassNode) <- byteCodeRepository.methodNode(methodRefClass.internalName, mi.name, mi.desc): Either[OptimizerWarning, (MethodNode, InternalName)] + methodDeclClass = classBTypeFromParsedClassfile(methodDeclClassNode) + res <- canInlineCall(mi.getOpcode, methodNode.access, methodDeclClass, methodRefClass) + } yield { + res + } + } + + case ivd: InvokeDynamicInsnNode => + // TODO @lry check necessary conditions to inline an indy, instead of giving up + Right(false) + + case ci: LdcInsnNode => ci.cst match { + case t: asm.Type => classIsAccessible(bTypeForDescriptorOrInternalNameFromClassfile(t.getInternalName)) + case _ => Right(true) + } + + case _ => Right(true) + } + + val it = instructions.iterator.asScala + @tailrec def find: Option[(AbstractInsnNode, Option[OptimizerWarning])] = { + if (!it.hasNext) None // all instructions are legal + else { + val i = it.next() + isLegal(i) match { + case Left(warning) => Some((i, Some(warning))) // checking isLegal for i failed + case Right(false) => Some((i, None)) // an illegal instruction was found + case _ => find + } + } + } + find + } +} |