diff options
Diffstat (limited to 'src/compiler/scala/tools/nsc/backend/jvm/opt/CallGraph.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/backend/jvm/opt/CallGraph.scala | 92 |
1 files changed, 85 insertions, 7 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/CallGraph.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/CallGraph.scala index 8abecdb261..96455c0e38 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/opt/CallGraph.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/CallGraph.scala @@ -9,7 +9,7 @@ package opt import scala.reflect.internal.util.{NoPosition, Position} import scala.tools.asm.tree.analysis.{Value, Analyzer, BasicInterpreter} -import scala.tools.asm.{Opcodes, Type} +import scala.tools.asm.{Opcodes, Type, Handle} import scala.tools.asm.tree._ import scala.collection.concurrent import scala.collection.convert.decorateAsScala._ @@ -24,7 +24,7 @@ class CallGraph[BT <: BTypes](val btypes: BT) { val callsites: concurrent.Map[MethodInsnNode, Callsite] = recordPerRunCache(concurrent.TrieMap.empty) - val closureInstantiations: concurrent.Map[InvokeDynamicInsnNode, (MethodNode, ClassBType)] = recordPerRunCache(concurrent.TrieMap.empty) + val closureInstantiations: concurrent.Map[InvokeDynamicInsnNode, ClosureInstantiation] = recordPerRunCache(concurrent.TrieMap.empty) def addClass(classNode: ClassNode): Unit = { val classType = classBTypeFromClassNode(classNode) @@ -33,14 +33,14 @@ class CallGraph[BT <: BTypes](val btypes: BT) { (calls, closureInits) = analyzeCallsites(m, classType) } { calls foreach (callsite => callsites(callsite.callsiteInstruction) = callsite) - closureInits foreach (indy => closureInstantiations(indy) = (m, classType)) + closureInits foreach (lmf => closureInstantiations(lmf.indy) = ClosureInstantiation(lmf, m, classType)) } } /** * Returns a list of callsites in the method, plus a list of closure instantiation indy instructions. */ - def analyzeCallsites(methodNode: MethodNode, definingClass: ClassBType): (List[Callsite], List[InvokeDynamicInsnNode]) = { + def analyzeCallsites(methodNode: MethodNode, definingClass: ClassBType): (List[Callsite], List[LambdaMetaFactoryCall]) = { case class CallsiteInfo(safeToInline: Boolean, safeToRewrite: Boolean, annotatedInline: Boolean, annotatedNoInline: Boolean, @@ -129,7 +129,7 @@ class CallGraph[BT <: BTypes](val btypes: BT) { } val callsites = new collection.mutable.ListBuffer[Callsite] - val closureInstantiations = new collection.mutable.ListBuffer[InvokeDynamicInsnNode] + val closureInstantiations = new collection.mutable.ListBuffer[LambdaMetaFactoryCall] methodNode.instructions.iterator.asScala foreach { case call: MethodInsnNode => @@ -173,8 +173,8 @@ class CallGraph[BT <: BTypes](val btypes: BT) { callsitePosition = callsitePositions.getOrElse(call, NoPosition) ) - case indy: InvokeDynamicInsnNode => - if (closureOptimizer.isClosureInstantiation(indy)) closureInstantiations += indy + case LambdaMetaFactoryCall(indy, samMethodType, implMethod, instantiatedMethodType) => + closureInstantiations += LambdaMetaFactoryCall(indy, samMethodType, implMethod, instantiatedMethodType) case _ => } @@ -236,4 +236,82 @@ class CallGraph[BT <: BTypes](val btypes: BT) { calleeInfoWarning: Option[CalleeInfoWarning]) { assert(!(safeToInline && safeToRewrite), s"A callee of ${callee.name} can be either safeToInline or safeToRewrite, but not both.") } + + final case class ClosureInstantiation(lambdaMetaFactoryCall: LambdaMetaFactoryCall, ownerMethod: MethodNode, ownerClass: ClassBType) { + override def toString = s"ClosureInstantiation($lambdaMetaFactoryCall, ${ownerMethod.name + ownerMethod.desc}, $ownerClass)" + } + final case class LambdaMetaFactoryCall(indy: InvokeDynamicInsnNode, samMethodType: Type, implMethod: Handle, instantiatedMethodType: Type) + + object LambdaMetaFactoryCall { + private val lambdaMetaFactoryInternalName: InternalName = "java/lang/invoke/LambdaMetafactory" + + private val metafactoryHandle = { + val metafactoryMethodName: String = "metafactory" + val metafactoryDesc: String = "(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodHandle;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite;" + new Handle(Opcodes.H_INVOKESTATIC, lambdaMetaFactoryInternalName, metafactoryMethodName, metafactoryDesc) + } + + private val altMetafactoryHandle = { + val altMetafactoryMethodName: String = "altMetafactory" + val altMetafactoryDesc: String = "(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;[Ljava/lang/Object;)Ljava/lang/invoke/CallSite;" + new Handle(Opcodes.H_INVOKESTATIC, lambdaMetaFactoryInternalName, altMetafactoryMethodName, altMetafactoryDesc) + } + + def unapply(insn: AbstractInsnNode): Option[(InvokeDynamicInsnNode, Type, Handle, Type)] = insn match { + case indy: InvokeDynamicInsnNode if indy.bsm == metafactoryHandle || indy.bsm == altMetafactoryHandle => + indy.bsmArgs match { + case Array(samMethodType: Type, implMethod: Handle, instantiatedMethodType: Type, xs@_*) => // xs binding because IntelliJ gets confused about _@_* + // LambdaMetaFactory performs a number of automatic adaptations when invoking the lambda + // implementation method (casting, boxing, unboxing, and primitive widening, see Javadoc). + // + // The closure optimizer supports only one of those adaptations: it will cast arguments + // to the correct type when re-writing a closure call to the body method. Example: + // + // val fun: String => String = l => l + // val l = List("") + // fun(l.head) + // + // The samMethodType of Function1 is `(Object)Object`, while the instantiatedMethodType + // is `(String)String`. The return type of `List.head` is `Object`. + // + // The implMethod has the signature `C$anonfun(String)String`. + // + // At the closure callsite, we have an `INVOKEINTERFACE Function1.apply (Object)Object`, + // so the object returned by `List.head` can be directly passed into the call (no cast). + // + // The closure object will cast the object to String before passing it to the implMethod. + // + // When re-writing the closure callsite to the implMethod, we have to insert a cast. + // + // The check below ensures that + // (1) the implMethod type has the expected singature (captured types plus argument types + // from instantiatedMethodType) + // (2) the receiver of the implMethod matches the first captured type + // (3) all parameters that are not the same in samMethodType and instantiatedMethodType + // are reference types, so that we can insert casts to perform the same adaptation + // that the closure object would. + + val isStatic = implMethod.getTag == Opcodes.H_INVOKESTATIC + val indyParamTypes = Type.getArgumentTypes(indy.desc) + val instantiatedMethodArgTypes = instantiatedMethodType.getArgumentTypes + val expectedImplMethodType = { + val paramTypes = (if (isStatic) indyParamTypes else indyParamTypes.tail) ++ instantiatedMethodArgTypes + Type.getMethodType(instantiatedMethodType.getReturnType, paramTypes: _*) + } + + val isIndyLambda = ( + Type.getType(implMethod.getDesc) == expectedImplMethodType // (1) + && (isStatic || implMethod.getOwner == indyParamTypes(0).getInternalName) // (2) + && samMethodType.getArgumentTypes.corresponds(instantiatedMethodArgTypes)((samArgType, instArgType) => + samArgType == instArgType || isReference(samArgType) && isReference(instArgType)) // (3) + ) + + if (isIndyLambda) Some((indy, samMethodType, implMethod, instantiatedMethodType)) + else None + + case _ => None + } + case _ => None + } + } } |