diff options
Diffstat (limited to 'src')
7 files changed, 301 insertions, 4 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala b/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala index 75aa0fc984..d3f09217cd 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala @@ -8,8 +8,9 @@ package scala.tools.nsc.backend.jvm import scala.tools.asm.tree.{InsnList, AbstractInsnNode, ClassNode, MethodNode} import java.io.{StringWriter, PrintWriter} import scala.tools.asm.util.{TraceClassVisitor, TraceMethodVisitor, Textifier} -import scala.tools.asm.ClassReader +import scala.tools.asm.{Attribute, ClassReader} import scala.collection.convert.decorateAsScala._ +import scala.tools.nsc.backend.jvm.opt.InlineInfoAttributePrototype object AsmUtils { @@ -49,7 +50,7 @@ object AsmUtils { def readClass(bytes: Array[Byte]): ClassNode = { val node = new ClassNode() - new ClassReader(bytes).accept(node, 0) + new ClassReader(bytes).accept(node, Array[Attribute](InlineInfoAttributePrototype), 0) node } diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala index 27827015c3..2ebf338f5e 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala @@ -3,9 +3,11 @@ * @author Martin Odersky */ -package scala.tools.nsc.backend.jvm +package scala.tools.nsc +package backend.jvm import scala.tools.nsc.Global +import scala.tools.nsc.backend.jvm.BTypes.{MethodInlineInfo, InlineInfo, InternalName} /** * This trait contains code shared between GenBCode and GenASM that depends on types defined in @@ -300,4 +302,97 @@ final class BCodeAsmCommon[G <: Global](val global: G) { } interfaces.map(_.typeSymbol) } + + /** + * This is a hack to work around SI-9111. The completer of `methodSym` may report type errors. We + * cannot change the typer context of the completer at this point and make it silent: the context + * captured when creating the completer in the namer. However, we can temporarily replace + * global.reporter (it's a var) to store errors. + */ + def completeSilentlyAndCheckErroneous(sym: Symbol): Boolean = { + if (sym.hasCompleteInfo) false + else { + val originalReporter = global.reporter + val storeReporter = new reporters.StoreReporter() + global.reporter = storeReporter + try { + sym.info + } finally { + global.reporter = originalReporter + } + sym.isErroneous + } + } + + /** + * Build the [[InlineInfo]] for a class symbol. + */ + def buildInlineInfoFromClassSymbol(classSym: Symbol, classSymToInternalName: Symbol => InternalName, methodSymToDescriptor: Symbol => String): InlineInfo = { + val selfType = { + // The mixin phase uses typeOfThis for the self parameter in implementation class methods. + val selfSym = classSym.typeOfThis.typeSymbol + if (selfSym != classSym) Some(classSymToInternalName(selfSym)) else None + } + + val isEffectivelyFinal = classSym.isEffectivelyFinal + + var warning = Option.empty[String] + + // Primitive methods cannot be inlined, so there's no point in building a MethodInlineInfo. Also, some + // primitive methods (e.g., `isInstanceOf`) have non-erased types, which confuses [[typeToBType]]. + val methodInlineInfos = classSym.info.decls.iterator.filter(m => m.isMethod && !scalaPrimitives.isPrimitive(m)).flatMap({ + case methodSym => + if (completeSilentlyAndCheckErroneous(methodSym)) { + // Happens due to SI-9111. Just don't provide any MethodInlineInfo for that method, we don't need fail the compiler. + if (!classSym.isJavaDefined) devWarning("SI-9111 should only be possible for Java classes") + warning = Some(s"Failed to get the type of a method of class symbol ${classSym.fullName} due to SI-9111") + None + } else { + val name = methodSym.javaSimpleName.toString // same as in genDefDef + val signature = name + methodSymToDescriptor(methodSym) + + // Some detours are required here because of changing flags (lateDEFERRED, lateMODULE): + // 1. Why the phase travel? Concrete trait methods obtain the lateDEFERRED flag in Mixin. + // This makes isEffectivelyFinalOrNotOverridden false, which would prevent non-final + // but non-overridden methods of sealed traits from being inlined. + // 2. Why the special case for `classSym.isImplClass`? Impl class symbols obtain the + // lateMODULE flag during Mixin. During the phase travel to exitingPickler, the late + // flag is ignored. The members are therefore not isEffectivelyFinal (their owner + // is not a module). Since we know that all impl class members are static, we can + // just take the shortcut. + val effectivelyFinal = classSym.isImplClass || exitingPickler(methodSym.isEffectivelyFinalOrNotOverridden) + + // Identify trait interface methods that have a static implementation in the implementation + // class. Invocations of these methods can be re-wrired directly to the static implementation + // if they are final or the receiver is known. + // + // Using `erasure.needsImplMethod` is not enough: it keeps field accessors, module getters + // and super accessors. When AddInterfaces creates the impl class, these methods are + // initially added to it. + // + // The mixin phase later on filters out most of these members from the impl class (see + // Mixin.isImplementedStatically). However, accessors for concrete lazy vals remain in the + // impl class after mixin. So the filter in mixin is not exactly what we need here (we + // want to identify concrete trait methods, not any accessors). So we check some symbol + // properties manually. + val traitMethodWithStaticImplementation = { + import symtab.Flags._ + classSym.isTrait && !classSym.isImplClass && + erasure.needsImplMethod(methodSym) && + !methodSym.isModule && + !(methodSym hasFlag (ACCESSOR | SUPERACCESSOR)) + } + + val info = MethodInlineInfo( + effectivelyFinal = effectivelyFinal, + traitMethodWithStaticImplementation = traitMethodWithStaticImplementation, + annotatedInline = methodSym.hasAnnotation(ScalaInlineClass), + annotatedNoInline = methodSym.hasAnnotation(ScalaNoInlineClass) + ) + Some((signature, info)) + } + }).toMap + + InlineInfo(selfType, isEffectivelyFinal, methodInlineInfos, warning) + } } diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala b/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala index a194fe8fe4..ec26ef9b48 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala @@ -936,4 +936,52 @@ object BTypes { * But that would create overhead in a Collection[InternalName]. */ type InternalName = String + + /** + * Metadata about a ClassBType, used by the inliner. + * + * More information may be added in the future to enable more elaborate inlinine heuristics. + * + * @param traitImplClassSelfType `Some(tp)` if this InlineInfo describes a trait, and the `self` + * parameter type of the methods in the implementation class is not + * the trait itself. Example: + * trait T { self: U => def f = 1 } + * Generates something like: + * class T$class { static def f(self: U) = 1 } + * + * In order to inline a trat method call, the INVOKEINTERFACE is + * rewritten to an INVOKESTATIC of the impl class, so we need the + * self type (U) to get the right signature. + * + * `None` if the self type is the interface type, or if this + * InlineInfo does not describe a trait. + * + * @param isEffectivelyFinal True if the class cannot have subclasses: final classes, module + * classes, trait impl classes. + * + * @param methodInfos The [[MethodInlineInfo]]s for the methods declared in this class. + * The map is indexed by the string s"$name$descriptor" (to + * disambiguate overloads). + */ + final case class InlineInfo(traitImplClassSelfType: Option[InternalName], + isEffectivelyFinal: Boolean, + methodInfos: Map[String, MethodInlineInfo], + warning: Option[String]) + + val EmptyInlineInfo = InlineInfo(None, false, Map.empty, None) + + /** + * Metadata about a method, used by the inliner. + * + * @param effectivelyFinal True if the method cannot be overridden (in Scala) + * @param traitMethodWithStaticImplementation True if the method is an interface method method of + * a trait method and has a static counterpart in the + * implementation class. + * @param annotatedInline True if the method is annotated `@inline` + * @param annotatedNoInline True if the method is annotated `@noinline` + */ + final case class MethodInlineInfo(effectivelyFinal: Boolean, + traitMethodWithStaticImplementation: Boolean, + annotatedInline: Boolean, + annotatedNoInline: Boolean) }
\ No newline at end of file diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala index 707336e5de..62268e1907 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala @@ -9,6 +9,7 @@ package backend.jvm import scala.collection.{ mutable, immutable } import scala.reflect.internal.pickling.{ PickleFormat, PickleBuffer } +import scala.tools.nsc.backend.jvm.opt.InlineInfoAttribute import scala.tools.nsc.symtab._ import scala.tools.asm import asm.Label @@ -1292,6 +1293,9 @@ abstract class GenASM extends SubComponent with BytecodeWriters { self => jclass.visitAttribute(if(ssa.isDefined) pickleMarkerLocal else pickleMarkerForeign) emitAnnotations(jclass, c.symbol.annotations ++ ssa) + if (!settings.YskipInlineInfoAttribute.value) + jclass.visitAttribute(InlineInfoAttribute(buildInlineInfoFromClassSymbol(c.symbol, javaName, javaType(_).getDescriptor))) + // typestate: entering mode with valid call sequences: // ( visitInnerClass | visitField | visitMethod )* visitEnd diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/InlineInfoAttribute.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/InlineInfoAttribute.scala new file mode 100644 index 0000000000..4812f2290f --- /dev/null +++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/InlineInfoAttribute.scala @@ -0,0 +1,147 @@ +/* NSC -- new Scala compiler + * Copyright 2005-2014 LAMP/EPFL + * @author Martin Odersky + */ + +package scala.tools.nsc +package backend.jvm +package opt + +import scala.tools.asm._ +import scala.tools.nsc.backend.jvm.BTypes.{InlineInfo, MethodInlineInfo} + +/** + * This attribute stores the InlineInfo for a ClassBType as an independent classfile attribute. + * The compiler does so for every class being compiled. + * + * The reason is that a precise InlineInfo can only be obtained if the symbol for a class is available. + * For example, we need to know if a method is final in Scala's terms, or if it has the @inline annotation. + * Looking up a class symbol for a given class filename is brittle (name-mangling). + * + * The attribute is also helpful for inlining mixin methods. The mixin phase only adds mixin method + * symbols to classes that are being compiled. For all other class symbols, there are no mixin members. + * However, the inliner requires an InlineInfo for inlining mixin members. That problem is solved by + * reading the InlineInfo from this attribute. + * + * In principle we could encode the InlineInfo into a Java annotation (instead of a classfile attribute). + * However, an attribute allows us to save many bits. In particular, note that the strings in an + * InlineInfo are serialized as references to constants in the constant pool, and those strings + * (traitImplClassSelfType, method names, method signatures) would exist in there anyway. So the + * ScalaInlineAttribute remains relatively compact. + */ +case class InlineInfoAttribute(inlineInfo: InlineInfo) extends Attribute(InlineInfoAttribute.attributeName) { + /** + * Not sure what this method is good for, it is not invoked anywhere in the ASM framework. However, + * the example in the ASM manual also overrides it to `false` for custom attributes, so it might be + * a good idea. + */ + override def isUnknown: Boolean = false + + /** + * Serialize the `inlineInfo` into a byte array. Strings are added to the constant pool and serialized + * as references. + */ + override def write(cw: ClassWriter, code: Array[Byte], len: Int, maxStack: Int, maxLocals: Int): ByteVector = { + val result = new ByteVector() + + result.putByte(InlineInfoAttribute.VERSION) + + var hasSelfIsFinal = 0 + if (inlineInfo.isEffectivelyFinal) hasSelfIsFinal |= 1 + if (inlineInfo.traitImplClassSelfType.isDefined) hasSelfIsFinal |= 2 + result.putByte(hasSelfIsFinal) + + for (selfInternalName <- inlineInfo.traitImplClassSelfType) { + result.putShort(cw.newUTF8(selfInternalName)) + } + + // The method count fits in a short (the methods_count in a classfile is also a short) + result.putShort(inlineInfo.methodInfos.size) + + // Sort the methodInfos for stability of classfiles + for ((nameAndType, info) <- inlineInfo.methodInfos.toList.sortBy(_._1)) { + val (name, desc) = nameAndType.span(_ != '(') + // Name and desc are added separately because a NameAndType entry also stores them separately. + // This makes sure that we use the existing constant pool entries for the method. + result.putShort(cw.newUTF8(name)) + result.putShort(cw.newUTF8(desc)) + + var inlineInfo = 0 + if (info.effectivelyFinal) inlineInfo |= 1 + if (info.traitMethodWithStaticImplementation) inlineInfo |= 2 + if (info.annotatedInline) inlineInfo |= 4 + if (info.annotatedNoInline) inlineInfo |= 8 + result.putByte(inlineInfo) + } + + result + } + + /** + * De-serialize the attribute into an InlineInfo. The attribute starts at cr.b(off), but we don't + * need to access that array directly, we can use the `read` methods provided by the ClassReader. + * + * `buf` is a pre-allocated character array that is guaranteed to be long enough to hold any + * string of the constant pool. So we can use it to invoke `cr.readUTF8`. + */ + override def read(cr: ClassReader, off: Int, len: Int, buf: Array[Char], codeOff: Int, labels: Array[Label]): InlineInfoAttribute = { + var next = off + + def nextByte() = { val r = cr.readByte(next) ; next += 1; r } + def nextUTF8() = { val r = cr.readUTF8(next, buf); next += 2; r } + def nextShort() = { val r = cr.readShort(next) ; next += 2; r } + + val version = nextByte() + if (version == 1) { + val hasSelfIsFinal = nextByte() + val isFinal = (hasSelfIsFinal & 1) != 0 + val hasSelf = (hasSelfIsFinal & 2) != 0 + + val self = if (hasSelf) { + val selfName = nextUTF8() + Some(selfName) + } else { + None + } + + val numEntries = nextShort() + val infos = (0 until numEntries).map(_ => { + val name = nextUTF8() + val desc = nextUTF8() + + val inlineInfo = nextByte() + val isFinal = (inlineInfo & 1) != 0 + val traitMethodWithStaticImplementation = (inlineInfo & 2) != 0 + val isInline = (inlineInfo & 4) != 0 + val isNoInline = (inlineInfo & 8) != 0 + (name + desc, MethodInlineInfo(isFinal, traitMethodWithStaticImplementation, isInline, isNoInline)) + }).toMap + + InlineInfoAttribute(InlineInfo(self, isFinal, infos, None)) + } else { + val msg = s"Cannot read ScalaInlineInfo version $version in classfile ${cr.getClassName}. Use a more recent compiler." + InlineInfoAttribute(BTypes.EmptyInlineInfo.copy(warning = Some(msg))) + } + } +} + +object InlineInfoAttribute { + /** + * [u1] version + * [u1] isEffectivelyFinal (<< 0), hasTraitImplClassSelfType (<< 1) + * [u2]? traitImplClassSelfType (reference) + * [u2] numMethodEntries + * [u2] name (reference) + * [u2] descriptor (reference) + * [u1] isFinal (<< 0), traitMethodWithStaticImplementation (<< 1), hasInlineAnnotation (<< 2), hasNoInlineAnnotation (<< 3) + */ + final val VERSION: Byte = 1 + + final val attributeName = "ScalaInlineInfo" +} + +/** + * In order to instruct the ASM framework to de-serialize the ScalaInlineInfo attribute, we need + * to pass a prototype instance when running the class reader. + */ +object InlineInfoAttributePrototype extends InlineInfoAttribute(InlineInfo(null, false, null, null)) diff --git a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala index a5b722612d..d7f4cca615 100644 --- a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala +++ b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala @@ -213,6 +213,8 @@ trait ScalaSettings extends AbsScalaSettings // the current standard is "inline" but we are moving towards "method" val Ydelambdafy = ChoiceSetting ("-Ydelambdafy", "strategy", "Strategy used for translating lambdas into JVM code.", List("inline", "method"), "inline") + val YskipInlineInfoAttribute = BooleanSetting("-Yskip-inline-info-attribute", "Do not add the ScalaInlineInfo attribute to classfiles generated by -Ybackend:GenASM") + object YoptChoices extends MultiChoiceEnumeration { val unreachableCode = Choice("unreachable-code", "Eliminate unreachable code, exception handlers protecting no instructions, debug information of eliminated variables.") val simplifyJumps = Choice("simplify-jumps", "Simplify branching instructions, eliminate unnecessary ones.") diff --git a/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala b/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala index f786ffb8f3..3591372bbe 100644 --- a/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala +++ b/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala @@ -55,7 +55,7 @@ abstract class AddInterfaces extends InfoTransform { self: Erasure => ) /** Does symbol need an implementation method? */ - private def needsImplMethod(sym: Symbol) = ( + def needsImplMethod(sym: Symbol) = ( sym.isMethod && isInterfaceMember(sym) && (!sym.hasFlag(DEFERRED | SUPERACCESSOR) || (sym hasFlag lateDEFERRED)) |