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Compiler for the SubScript extension of the Scala Programming Language
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/* NSC -- new Scala compiler
* Copyright 2005-2012 LAMP/EPFL
* @author Martin Odersky
*/
package scala
package tools.nsc
package backend.jvm
import scala.tools.asm
import scala.collection.mutable
import scala.tools.nsc.io.AbstractFile
/*
* Traits encapsulating functionality to convert Scala AST Trees into ASM ClassNodes.
*
* @author Miguel Garcia, http://lamp.epfl.ch/~magarcia/ScalaCompilerCornerReloaded
* @version 1.0
*
*/
abstract class BCodeHelpers extends BCodeIdiomatic with BytecodeWriters {
import global._
import bTypes._
import coreBTypes._
/*
* must-single-thread
*/
def getFileForClassfile(base: AbstractFile, clsName: String, suffix: String): AbstractFile = {
getFile(base, clsName, suffix)
}
/*
* must-single-thread
*/
def getOutFolder(csym: Symbol, cName: String, cunit: CompilationUnit): _root_.scala.tools.nsc.io.AbstractFile = {
try {
outputDirectory(csym)
} catch {
case ex: Throwable =>
reporter.error(cunit.body.pos, s"Couldn't create file for class $cName\n${ex.getMessage}")
null
}
}
var pickledBytes = 0 // statistics
// -----------------------------------------------------------------------------------------
// finding the least upper bound in agreement with the bytecode verifier (given two internal names handed by ASM)
// Background:
// http://gallium.inria.fr/~xleroy/publi/bytecode-verification-JAR.pdf
// http://comments.gmane.org/gmane.comp.java.vm.languages/2293
// https://issues.scala-lang.org/browse/SI-3872
// -----------------------------------------------------------------------------------------
/* An `asm.ClassWriter` that uses `jvmWiseLUB()`
* The internal name of the least common ancestor of the types given by inameA and inameB.
* It's what ASM needs to know in order to compute stack map frames, http://asm.ow2.org/doc/developer-guide.html#controlflow
*/
final class CClassWriter(flags: Int) extends asm.ClassWriter(flags) {
/**
* This method is thread-safe: it depends only on the BTypes component, which does not depend
* on global. TODO @lry move to a different place where no global is in scope, on bTypes.
*/
override def getCommonSuperClass(inameA: String, inameB: String): String = {
val a = classBTypeFromInternalName(inameA)
val b = classBTypeFromInternalName(inameB)
val lub = a.jvmWiseLUB(b)
val lubName = lub.internalName
assert(lubName != "scala/Any")
lubName // ASM caches the answer during the lifetime of a ClassWriter. We outlive that. Not sure whether caching on our side would improve things.
}
}
/*
* must-single-thread
*/
object isJavaEntryPoint {
/*
* must-single-thread
*/
def apply(sym: Symbol, csymCompUnit: CompilationUnit): Boolean = {
def fail(msg: String, pos: Position = sym.pos) = {
reporter.warning(sym.pos,
sym.name +
s" has a main method with parameter type Array[String], but ${sym.fullName('.')} will not be a runnable program.\n Reason: $msg"
// TODO: make this next claim true, if possible
// by generating valid main methods as static in module classes
// not sure what the jvm allows here
// + " You can still run the program by calling it as " + sym.javaSimpleName + " instead."
)
false
}
def failNoForwarder(msg: String) = {
fail(s"$msg, which means no static forwarder can be generated.\n")
}
val possibles = if (sym.hasModuleFlag) (sym.tpe nonPrivateMember nme.main).alternatives else Nil
val hasApproximate = possibles exists { m =>
m.info match {
case MethodType(p :: Nil, _) => p.tpe.typeSymbol == definitions.ArrayClass
case _ => false
}
}
// At this point it's a module with a main-looking method, so either succeed or warn that it isn't.
hasApproximate && {
// Before erasure so we can identify generic mains.
enteringErasure {
val companion = sym.linkedClassOfClass
if (definitions.hasJavaMainMethod(companion))
failNoForwarder("companion contains its own main method")
else if (companion.tpe.member(nme.main) != NoSymbol)
// this is only because forwarders aren't smart enough yet
failNoForwarder("companion contains its own main method (implementation restriction: no main is allowed, regardless of signature)")
else if (companion.isTrait)
failNoForwarder("companion is a trait")
// Now either succeeed, or issue some additional warnings for things which look like
// attempts to be java main methods.
else (possibles exists definitions.isJavaMainMethod) || {
possibles exists { m =>
m.info match {
case PolyType(_, _) =>
fail("main methods cannot be generic.")
case MethodType(params, res) =>
if (res.typeSymbol :: params exists (_.isAbstractType))
fail("main methods cannot refer to type parameters or abstract types.", m.pos)
else
definitions.isJavaMainMethod(m) || fail("main method must have exact signature (Array[String])Unit", m.pos)
case tp =>
fail(s"don't know what this is: $tp", m.pos)
}
}
}
}
}
}
}
/*
* must-single-thread
*/
def initBytecodeWriter(entryPoints: List[Symbol]): BytecodeWriter = {
settings.outputDirs.getSingleOutput match {
case Some(f) if f hasExtension "jar" =>
// If no main class was specified, see if there's only one
// entry point among the classes going into the jar.
if (settings.mainClass.isDefault) {
entryPoints map (_.fullName('.')) match {
case Nil =>
log("No Main-Class designated or discovered.")
case name :: Nil =>
log(s"Unique entry point: setting Main-Class to $name")
settings.mainClass.value = name
case names =>
log(s"No Main-Class due to multiple entry points:\n ${names.mkString("\n ")}")
}
}
else log(s"Main-Class was specified: ${settings.mainClass.value}")
new DirectToJarfileWriter(f.file)
case _ => factoryNonJarBytecodeWriter()
}
}
/*
* must-single-thread
*/
def fieldSymbols(cls: Symbol): List[Symbol] = {
for (f <- cls.info.decls.toList ;
if !f.isMethod && f.isTerm && !f.isModule
) yield f
}
/*
* can-multi-thread
*/
def methodSymbols(cd: ClassDef): List[Symbol] = {
cd.impl.body collect { case dd: DefDef => dd.symbol }
}
/*
* must-single-thread
*/
def serialVUID(csym: Symbol): Option[Long] = csym getAnnotation definitions.SerialVersionUIDAttr collect {
case AnnotationInfo(_, _, (_, LiteralAnnotArg(const)) :: Nil) => const.longValue
}
/*
* Populates the InnerClasses JVM attribute with `refedInnerClasses`.
* In addition to inner classes mentioned somewhere in `jclass` (where `jclass` is a class file being emitted)
* `refedInnerClasses` should contain those inner classes defined as direct member classes of `jclass`
* but otherwise not mentioned in `jclass`.
*
* `refedInnerClasses` may contain duplicates,
* need not contain the enclosing inner classes of each inner class it lists (those are looked up for consistency).
*
* This method serializes in the InnerClasses JVM attribute in an appropriate order,
* not necessarily that given by `refedInnerClasses`.
*
* can-multi-thread
*/
final def addInnerClassesASM(jclass: asm.ClassVisitor, refedInnerClasses: List[ClassBType]) {
val allNestedClasses = refedInnerClasses.flatMap(_.enclosingNestedClassesChain).distinct
// sorting ensures nested classes are listed after their enclosing class thus satisfying the Eclipse Java compiler
for (nestedClass <- allNestedClasses.sortBy(_.internalName.toString)) {
// Extract the innerClassEntry - we know it exists, enclosingNestedClassesChain only returns nested classes.
val Some(e) = nestedClass.innerClassAttributeEntry
jclass.visitInnerClass(e.name, e.outerName, e.innerName, e.flags)
}
}
/*
* Custom attribute (JVMS 4.7.1) "ScalaSig" used as marker only
* i.e., the pickle is contained in a custom annotation, see:
* (1) `addAnnotations()`,
* (2) SID # 10 (draft) - Storage of pickled Scala signatures in class files, http://www.scala-lang.org/sid/10
* (3) SID # 5 - Internals of Scala Annotations, http://www.scala-lang.org/sid/5
* That annotation in turn is not related to the "java-generic-signature" (JVMS 4.7.9)
* other than both ending up encoded as attributes (JVMS 4.7)
* (with the caveat that the "ScalaSig" attribute is associated to some classes,
* while the "Signature" attribute can be associated to classes, methods, and fields.)
*
*/
trait BCPickles {
import scala.reflect.internal.pickling.{ PickleFormat, PickleBuffer }
val versionPickle = {
val vp = new PickleBuffer(new Array[Byte](16), -1, 0)
assert(vp.writeIndex == 0, vp)
vp writeNat PickleFormat.MajorVersion
vp writeNat PickleFormat.MinorVersion
vp writeNat 0
vp
}
/*
* can-multi-thread
*/
def createJAttribute(name: String, b: Array[Byte], offset: Int, len: Int): asm.Attribute = {
val dest = new Array[Byte](len)
System.arraycopy(b, offset, dest, 0, len)
new asm.CustomAttr(name, dest)
}
/*
* can-multi-thread
*/
def pickleMarkerLocal = {
createJAttribute(tpnme.ScalaSignatureATTR.toString, versionPickle.bytes, 0, versionPickle.writeIndex)
}
/*
* can-multi-thread
*/
def pickleMarkerForeign = {
createJAttribute(tpnme.ScalaATTR.toString, new Array[Byte](0), 0, 0)
}
/* Returns a ScalaSignature annotation if it must be added to this class, none otherwise.
* This annotation must be added to the class' annotations list when generating them.
*
* Depending on whether the returned option is defined, it adds to `jclass` one of:
* (a) the ScalaSig marker attribute
* (indicating that a scala-signature-annotation aka pickle is present in this class); or
* (b) the Scala marker attribute
* (indicating that a scala-signature-annotation aka pickle is to be found in another file).
*
*
* @param jclassName The class file that is being readied.
* @param sym The symbol for which the signature has been entered in the symData map.
* This is different than the symbol
* that is being generated in the case of a mirror class.
* @return An option that is:
* - defined and contains an AnnotationInfo of the ScalaSignature type,
* instantiated with the pickle signature for sym.
* - empty if the jclass/sym pair must not contain a pickle.
*
* must-single-thread
*/
def getAnnotPickle(jclassName: String, sym: Symbol): Option[AnnotationInfo] = {
currentRun.symData get sym match {
case Some(pickle) if !nme.isModuleName(newTermName(jclassName)) =>
val scalaAnnot = {
val sigBytes = ScalaSigBytes(pickle.bytes.take(pickle.writeIndex))
AnnotationInfo(sigBytes.sigAnnot, Nil, (nme.bytes, sigBytes) :: Nil)
}
pickledBytes += pickle.writeIndex
currentRun.symData -= sym
currentRun.symData -= sym.companionSymbol
Some(scalaAnnot)
case _ =>
None
}
}
} // end of trait BCPickles
trait BCInnerClassGen {
def debugLevel = settings.debuginfo.indexOfChoice
final val emitSource = debugLevel >= 1
final val emitLines = debugLevel >= 2
final val emitVars = debugLevel >= 3
/*
* Contains class-symbols that:
* (a) are known to denote inner classes
* (b) are mentioned somewhere in the class being generated.
*
* In other words, the lifetime of `innerClassBufferASM` is associated to "the class being generated".
*/
final val innerClassBufferASM = mutable.Set.empty[ClassBType]
/**
* The class internal name for a given class symbol. If the symbol describes a nested class, the
* ClassBType is added to the innerClassBufferASM.
*/
final def internalName(sym: Symbol): String = {
// For each java class, the scala compiler creates a class and a module (thus a module class).
// If the `sym` is a java module class, we use the java class instead. This ensures that we
// register the class (instead of the module class) in innerClassBufferASM.
// The two symbols have the same name, so the resulting internalName is the same.
val classSym = if (sym.isJavaDefined && sym.isModuleClass) sym.linkedClassOfClass else sym
getClassBTypeAndRegisterInnerClass(classSym).internalName
}
private def assertClassNotArray(sym: Symbol): Unit = {
assert(sym.isClass, sym)
assert(sym != definitions.ArrayClass || isCompilingArray, sym)
}
private def assertClassNotArrayNotPrimitive(sym: Symbol): Unit = {
assertClassNotArray(sym)
assert(!primitiveTypeMap.contains(sym) || isCompilingPrimitive, sym)
}
/**
* The ClassBType for a class symbol. If the class is nested, the ClassBType is added to the
* innerClassBufferASM.
*
* The class symbol scala.Nothing is mapped to the class scala.runtime.Nothing$. Similarly,
* scala.Null is mapped to scala.runtime.Null$. This is because there exist no class files
* for the Nothing / Null. If used for example as a parameter type, we use the runtime classes
* in the classfile method signature.
*
* Note that the referenced class symbol may be an implementation class. For example when
* compiling a mixed-in method that forwards to the static method in the implementation class,
* the class descriptor of the receiver (the implementation class) is obtained by creating the
* ClassBType.
*/
final def getClassBTypeAndRegisterInnerClass(sym: Symbol): ClassBType = {
assertClassNotArrayNotPrimitive(sym)
if (sym == definitions.NothingClass) RT_NOTHING
else if (sym == definitions.NullClass) RT_NULL
else {
val r = classBTypeFromSymbol(sym)
if (r.isNestedClass) innerClassBufferASM += r
r
}
}
/**
* This method returns the BType for a type reference, for example a parameter type.
*
* If the result is a ClassBType for a nested class, it is added to the innerClassBufferASM.
*
* If `t` references a class, toTypeKind ensures that the class is not an implementation class.
* See also comment on getClassBTypeAndRegisterInnerClass, which is invoked for implementation
* classes.
*/
final def toTypeKind(t: Type): BType = {
import definitions.ArrayClass
/**
* Primitive types are represented as TypeRefs to the class symbol of, for example, scala.Int.
* The `primitiveTypeMap` maps those class symbols to the corresponding PrimitiveBType.
*/
def primitiveOrClassToBType(sym: Symbol): BType = {
assertClassNotArray(sym)
assert(!sym.isImplClass, sym)
primitiveTypeMap.getOrElse(sym, getClassBTypeAndRegisterInnerClass(sym))
}
/**
* When compiling Array.scala, the type parameter T is not erased and shows up in method
* signatures, e.g. `def apply(i: Int): T`. A TyperRef to T is replaced by ObjectReference.
*/
def nonClassTypeRefToBType(sym: Symbol): ClassBType = {
assert(sym.isType && isCompilingArray, sym)
ObjectReference
}
t.dealiasWiden match {
case TypeRef(_, ArrayClass, List(arg)) => ArrayBType(toTypeKind(arg)) // Array type such as Array[Int] (kept by erasure)
case TypeRef(_, sym, _) if !sym.isClass => nonClassTypeRefToBType(sym) // See comment on nonClassTypeRefToBType
case TypeRef(_, sym, _) => primitiveOrClassToBType(sym) // Common reference to a type such as scala.Int or java.lang.String
case ClassInfoType(_, _, sym) => primitiveOrClassToBType(sym) // We get here, for example, for genLoadModule, which invokes toTypeKind(moduleClassSymbol.info)
/* AnnotatedType should (probably) be eliminated by erasure. However we know it happens for
* meta-annotated annotations (@(ann @getter) val x = 0), so we don't emit a warning.
* The type in the AnnotationInfo is an AnnotatedTpe. Tested in jvm/annotations.scala.
*/
case a @ AnnotatedType(_, t) =>
debuglog(s"typeKind of annotated type $a")
toTypeKind(t)
/* ExistentialType should (probably) be eliminated by erasure. We know they get here for
* classOf constants:
* class C[T]
* class T { final val k = classOf[C[_]] }
*/
case e @ ExistentialType(_, t) =>
debuglog(s"typeKind of existential type $e")
toTypeKind(t)
/* The cases below should probably never occur. They are kept for now to avoid introducing
* new compiler crashes, but we added a warning. The compiler / library bootstrap and the
* test suite don't produce any warning.
*/
case tp =>
currentUnit.warning(tp.typeSymbol.pos,
s"an unexpected type representation reached the compiler backend while compiling $currentUnit: $tp. " +
"If possible, please file a bug on issues.scala-lang.org.")
tp match {
case ThisType(ArrayClass) => ObjectReference // was introduced in 9b17332f11 to fix SI-999, but this code is not reached in its test, or any other test
case ThisType(sym) => getClassBTypeAndRegisterInnerClass(sym)
case SingleType(_, sym) => primitiveOrClassToBType(sym)
case ConstantType(_) => toTypeKind(t.underlying)
case RefinedType(parents, _) => parents.map(toTypeKind(_).asClassBType).reduceLeft((a, b) => a.jvmWiseLUB(b))
}
}
}
/*
* must-single-thread
*/
final def asmMethodType(msym: Symbol): MethodBType = {
assert(msym.isMethod, s"not a method-symbol: $msym")
val resT: BType =
if (msym.isClassConstructor || msym.isConstructor) UNIT
else toTypeKind(msym.tpe.resultType)
MethodBType(msym.tpe.paramTypes map toTypeKind, resT)
}
/**
* The jvm descriptor of a type. If `t` references a nested class, its ClassBType is added to
* the innerClassBufferASM.
*/
final def descriptor(t: Type): String = { toTypeKind(t).descriptor }
/**
* The jvm descriptor for a symbol. If `sym` represents a nested class, its ClassBType is added
* to the innerClassBufferASM.
*/
final def descriptor(sym: Symbol): String = { getClassBTypeAndRegisterInnerClass(sym).descriptor }
} // end of trait BCInnerClassGen
trait BCAnnotGen extends BCInnerClassGen {
import genASM.{ubytesToCharArray, arrEncode}
import bCodeAsmCommon.{shouldEmitAnnotation, isRuntimeVisible}
/*
* can-multi-thread
*/
private def strEncode(sb: ScalaSigBytes): String = {
val ca = ubytesToCharArray(sb.sevenBitsMayBeZero)
new java.lang.String(ca)
// debug val bvA = new asm.ByteVector; bvA.putUTF8(s)
// debug val enc: Array[Byte] = scala.reflect.internal.pickling.ByteCodecs.encode(bytes)
// debug assert(enc(idx) == bvA.getByte(idx + 2))
// debug assert(bvA.getLength == enc.size + 2)
}
/*
* For arg a LiteralAnnotArg(constt) with const.tag in {ClazzTag, EnumTag}
* as well as for arg a NestedAnnotArg
* must-single-thread
* Otherwise it's safe to call from multiple threads.
*/
def emitArgument(av: asm.AnnotationVisitor,
name: String,
arg: ClassfileAnnotArg) {
(arg: @unchecked) match {
case LiteralAnnotArg(const) =>
if (const.isNonUnitAnyVal) { av.visit(name, const.value) }
else {
const.tag match {
case StringTag =>
assert(const.value != null, const) // TODO this invariant isn't documented in `case class Constant`
av.visit(name, const.stringValue) // `stringValue` special-cases null, but that execution path isn't exercised for a const with StringTag
case ClazzTag => av.visit(name, toTypeKind(const.typeValue).toASMType)
case EnumTag =>
val edesc = descriptor(const.tpe) // the class descriptor of the enumeration class.
val evalue = const.symbolValue.name.toString // value the actual enumeration value.
av.visitEnum(name, edesc, evalue)
}
}
case sb @ ScalaSigBytes(bytes) =>
// see http://www.scala-lang.org/sid/10 (Storage of pickled Scala signatures in class files)
// also JVMS Sec. 4.7.16.1 The element_value structure and JVMS Sec. 4.4.7 The CONSTANT_Utf8_info Structure.
if (sb.fitsInOneString) {
av.visit(name, strEncode(sb))
} else {
val arrAnnotV: asm.AnnotationVisitor = av.visitArray(name)
for(arg <- genASM.arrEncode(sb)) { arrAnnotV.visit(name, arg) }
arrAnnotV.visitEnd()
} // for the lazy val in ScalaSigBytes to be GC'ed, the invoker of emitAnnotations() should hold the ScalaSigBytes in a method-local var that doesn't escape.
case ArrayAnnotArg(args) =>
val arrAnnotV: asm.AnnotationVisitor = av.visitArray(name)
for(arg <- args) { emitArgument(arrAnnotV, null, arg) }
arrAnnotV.visitEnd()
case NestedAnnotArg(annInfo) =>
val AnnotationInfo(typ, args, assocs) = annInfo
assert(args.isEmpty, args)
val desc = descriptor(typ) // the class descriptor of the nested annotation class
val nestedVisitor = av.visitAnnotation(name, desc)
emitAssocs(nestedVisitor, assocs)
}
}
/*
* In general,
* must-single-thread
* but not necessarily always.
*/
def emitAssocs(av: asm.AnnotationVisitor, assocs: List[(Name, ClassfileAnnotArg)]) {
for ((name, value) <- assocs) {
emitArgument(av, name.toString(), value)
}
av.visitEnd()
}
/*
* must-single-thread
*/
def emitAnnotations(cw: asm.ClassVisitor, annotations: List[AnnotationInfo]) {
for(annot <- annotations; if shouldEmitAnnotation(annot)) {
val AnnotationInfo(typ, args, assocs) = annot
assert(args.isEmpty, args)
val av = cw.visitAnnotation(descriptor(typ), isRuntimeVisible(annot))
emitAssocs(av, assocs)
}
}
/*
* must-single-thread
*/
def emitAnnotations(mw: asm.MethodVisitor, annotations: List[AnnotationInfo]) {
for(annot <- annotations; if shouldEmitAnnotation(annot)) {
val AnnotationInfo(typ, args, assocs) = annot
assert(args.isEmpty, args)
val av = mw.visitAnnotation(descriptor(typ), isRuntimeVisible(annot))
emitAssocs(av, assocs)
}
}
/*
* must-single-thread
*/
def emitAnnotations(fw: asm.FieldVisitor, annotations: List[AnnotationInfo]) {
for(annot <- annotations; if shouldEmitAnnotation(annot)) {
val AnnotationInfo(typ, args, assocs) = annot
assert(args.isEmpty, args)
val av = fw.visitAnnotation(descriptor(typ), isRuntimeVisible(annot))
emitAssocs(av, assocs)
}
}
/*
* must-single-thread
*/
def emitParamAnnotations(jmethod: asm.MethodVisitor, pannotss: List[List[AnnotationInfo]]) {
val annotationss = pannotss map (_ filter shouldEmitAnnotation)
if (annotationss forall (_.isEmpty)) return
for ((annots, idx) <- annotationss.zipWithIndex;
annot <- annots) {
val AnnotationInfo(typ, args, assocs) = annot
assert(args.isEmpty, args)
val pannVisitor: asm.AnnotationVisitor = jmethod.visitParameterAnnotation(idx, descriptor(typ), isRuntimeVisible(annot))
emitAssocs(pannVisitor, assocs)
}
}
} // end of trait BCAnnotGen
trait BCJGenSigGen {
def getCurrentCUnit(): CompilationUnit
/* @return
* - `null` if no Java signature is to be added (`null` is what ASM expects in these cases).
* - otherwise the signature in question
*
* must-single-thread
*/
def getGenericSignature(sym: Symbol, owner: Symbol): String = genASM.getGenericSignature(sym, owner, getCurrentCUnit())
} // end of trait BCJGenSigGen
trait BCForwardersGen extends BCAnnotGen with BCJGenSigGen {
/* Adds a @remote annotation, actual use unknown.
*
* Invoked from genMethod() and addForwarder().
*
* must-single-thread
*/
def addRemoteExceptionAnnot(isRemoteClass: Boolean, isJMethodPublic: Boolean, meth: Symbol) {
val needsAnnotation = (
( isRemoteClass ||
isRemote(meth) && isJMethodPublic
) && !(meth.throwsAnnotations contains definitions.RemoteExceptionClass)
)
if (needsAnnotation) {
val c = Constant(definitions.RemoteExceptionClass.tpe)
val arg = Literal(c) setType c.tpe
meth.addAnnotation(appliedType(definitions.ThrowsClass, c.tpe), arg)
}
}
/* Add a forwarder for method m. Used only from addForwarders().
*
* must-single-thread
*/
private def addForwarder(isRemoteClass: Boolean, jclass: asm.ClassVisitor, module: Symbol, m: Symbol) {
val moduleName = internalName(module)
val methodInfo = module.thisType.memberInfo(m)
val paramJavaTypes: List[BType] = methodInfo.paramTypes map toTypeKind
// val paramNames = 0 until paramJavaTypes.length map ("x_" + _)
/* Forwarders must not be marked final,
* as the JVM will not allow redefinition of a final static method,
* and we don't know what classes might be subclassing the companion class. See SI-4827.
*/
// TODO: evaluate the other flags we might be dropping on the floor here.
// TODO: ACC_SYNTHETIC ?
val flags = GenBCode.PublicStatic | (
if (m.isVarargsMethod) asm.Opcodes.ACC_VARARGS else 0
)
// TODO needed? for(ann <- m.annotations) { ann.symbol.initialize }
val jgensig = genASM.staticForwarderGenericSignature(m, module, getCurrentCUnit())
addRemoteExceptionAnnot(isRemoteClass, hasPublicBitSet(flags), m)
val (throws, others) = m.annotations partition (_.symbol == definitions.ThrowsClass)
val thrownExceptions: List[String] = getExceptions(throws)
val jReturnType = toTypeKind(methodInfo.resultType)
val mdesc = MethodBType(paramJavaTypes, jReturnType).descriptor
val mirrorMethodName = m.javaSimpleName.toString
val mirrorMethod: asm.MethodVisitor = jclass.visitMethod(
flags,
mirrorMethodName,
mdesc,
jgensig,
mkArray(thrownExceptions)
)
emitAnnotations(mirrorMethod, others)
emitParamAnnotations(mirrorMethod, m.info.params.map(_.annotations))
mirrorMethod.visitCode()
mirrorMethod.visitFieldInsn(asm.Opcodes.GETSTATIC, moduleName, strMODULE_INSTANCE_FIELD, descriptor(module))
var index = 0
for(jparamType <- paramJavaTypes) {
mirrorMethod.visitVarInsn(jparamType.typedOpcode(asm.Opcodes.ILOAD), index)
assert(!jparamType.isInstanceOf[MethodBType], jparamType)
index += jparamType.size
}
mirrorMethod.visitMethodInsn(asm.Opcodes.INVOKEVIRTUAL, moduleName, mirrorMethodName, asmMethodType(m).descriptor, false)
mirrorMethod.visitInsn(jReturnType.typedOpcode(asm.Opcodes.IRETURN))
mirrorMethod.visitMaxs(0, 0) // just to follow protocol, dummy arguments
mirrorMethod.visitEnd()
}
/* Add forwarders for all methods defined in `module` that don't conflict
* with methods in the companion class of `module`. A conflict arises when
* a method with the same name is defined both in a class and its companion object:
* method signature is not taken into account.
*
* must-single-thread
*/
def addForwarders(isRemoteClass: Boolean, jclass: asm.ClassVisitor, jclassName: String, moduleClass: Symbol) {
assert(moduleClass.isModuleClass, moduleClass)
debuglog(s"Dumping mirror class for object: $moduleClass")
val linkedClass = moduleClass.companionClass
lazy val conflictingNames: Set[Name] = {
(linkedClass.info.members collect { case sym if sym.name.isTermName => sym.name }).toSet
}
debuglog(s"Potentially conflicting names for forwarders: $conflictingNames")
for (m <- moduleClass.info.membersBasedOnFlags(bCodeAsmCommon.ExcludedForwarderFlags, symtab.Flags.METHOD)) {
if (m.isType || m.isDeferred || (m.owner eq definitions.ObjectClass) || m.isConstructor)
debuglog(s"No forwarder for '$m' from $jclassName to '$moduleClass'")
else if (conflictingNames(m.name))
log(s"No forwarder for $m due to conflict with ${linkedClass.info.member(m.name)}")
else if (m.hasAccessBoundary)
log(s"No forwarder for non-public member $m")
else {
log(s"Adding static forwarder for '$m' from $jclassName to '$moduleClass'")
addForwarder(isRemoteClass, jclass, moduleClass, m)
}
}
}
/*
* Quoting from JVMS 4.7.5 The Exceptions Attribute
* "The Exceptions attribute indicates which checked exceptions a method may throw.
* There may be at most one Exceptions attribute in each method_info structure."
*
* The contents of that attribute are determined by the `String[] exceptions` argument to ASM's ClassVisitor.visitMethod()
* This method returns such list of internal names.
*
* must-single-thread
*/
def getExceptions(excs: List[AnnotationInfo]): List[String] = {
for (ThrownException(exc) <- excs.distinct)
yield internalName(exc)
}
} // end of trait BCForwardersGen
trait BCClassGen extends BCInnerClassGen {
// Used as threshold above which a tableswitch bytecode instruction is preferred over a lookupswitch.
// There's a space tradeoff between these multi-branch instructions (details in the JVM spec).
// The particular value in use for `MIN_SWITCH_DENSITY` reflects a heuristic.
val MIN_SWITCH_DENSITY = 0.7
/*
* Add public static final field serialVersionUID with value `id`
*
* can-multi-thread
*/
def addSerialVUID(id: Long, jclass: asm.ClassVisitor) {
// add static serialVersionUID field if `clasz` annotated with `@SerialVersionUID(uid: Long)`
jclass.visitField(
GenBCode.PublicStaticFinal,
"serialVersionUID",
"J",
null, // no java-generic-signature
new java.lang.Long(id)
).visitEnd()
}
} // end of trait BCClassGen
/* functionality for building plain and mirror classes */
abstract class JCommonBuilder
extends BCInnerClassGen
with BCAnnotGen
with BCForwardersGen
with BCPickles { }
/* builder of mirror classes */
class JMirrorBuilder extends JCommonBuilder {
private var cunit: CompilationUnit = _
def getCurrentCUnit(): CompilationUnit = cunit;
/* Generate a mirror class for a top-level module. A mirror class is a class
* containing only static methods that forward to the corresponding method
* on the MODULE instance of the given Scala object. It will only be
* generated if there is no companion class: if there is, an attempt will
* instead be made to add the forwarder methods to the companion class.
*
* must-single-thread
*/
def genMirrorClass(moduleClass: Symbol, cunit: CompilationUnit): asm.tree.ClassNode = {
assert(moduleClass.isModuleClass)
assert(moduleClass.companionClass == NoSymbol, moduleClass)
innerClassBufferASM.clear()
this.cunit = cunit
val moduleName = internalName(moduleClass) // + "$"
val mirrorName = moduleName.substring(0, moduleName.length() - 1)
val flags = (asm.Opcodes.ACC_SUPER | asm.Opcodes.ACC_PUBLIC | asm.Opcodes.ACC_FINAL)
val mirrorClass = new asm.tree.ClassNode
mirrorClass.visit(
classfileVersion,
flags,
mirrorName,
null /* no java-generic-signature */,
ObjectReference.internalName,
EMPTY_STRING_ARRAY
)
if (emitSource) {
mirrorClass.visitSource("" + cunit.source,
null /* SourceDebugExtension */)
}
val ssa = getAnnotPickle(mirrorName, moduleClass.companionSymbol)
mirrorClass.visitAttribute(if (ssa.isDefined) pickleMarkerLocal else pickleMarkerForeign)
emitAnnotations(mirrorClass, moduleClass.annotations ++ ssa)
addForwarders(isRemote(moduleClass), mirrorClass, mirrorName, moduleClass)
innerClassBufferASM ++= classBTypeFromSymbol(moduleClass).info.memberClasses
addInnerClassesASM(mirrorClass, innerClassBufferASM.toList)
mirrorClass.visitEnd()
("" + moduleClass.name) // this side-effect is necessary, really.
mirrorClass
}
} // end of class JMirrorBuilder
/* builder of bean info classes */
class JBeanInfoBuilder extends BCInnerClassGen {
/*
* Generate a bean info class that describes the given class.
*
* @author Ross Judson ([email protected])
*
* must-single-thread
*/
def genBeanInfoClass(cls: Symbol, cunit: CompilationUnit, fieldSymbols: List[Symbol], methodSymbols: List[Symbol]): asm.tree.ClassNode = {
def javaSimpleName(s: Symbol): String = { s.javaSimpleName.toString }
innerClassBufferASM.clear()
val flags = javaFlags(cls)
val beanInfoName = (internalName(cls) + "BeanInfo")
val beanInfoClass = new asm.tree.ClassNode
beanInfoClass.visit(
classfileVersion,
flags,
beanInfoName,
null, // no java-generic-signature
"scala/beans/ScalaBeanInfo",
EMPTY_STRING_ARRAY
)
beanInfoClass.visitSource(
cunit.source.toString,
null /* SourceDebugExtension */
)
var fieldList = List[String]()
for (f <- fieldSymbols if f.hasGetter;
g = f.getter(cls);
s = f.setter(cls);
if g.isPublic && !(f.name startsWith "$")
) {
// inserting $outer breaks the bean
fieldList = javaSimpleName(f) :: javaSimpleName(g) :: (if (s != NoSymbol) javaSimpleName(s) else null) :: fieldList
}
val methodList: List[String] =
for (m <- methodSymbols
if !m.isConstructor &&
m.isPublic &&
!(m.name startsWith "$") &&
!m.isGetter &&
!m.isSetter)
yield javaSimpleName(m)
val constructor = beanInfoClass.visitMethod(
asm.Opcodes.ACC_PUBLIC,
INSTANCE_CONSTRUCTOR_NAME,
"()V",
null, // no java-generic-signature
EMPTY_STRING_ARRAY // no throwable exceptions
)
val stringArrayJType: BType = ArrayBType(StringReference)
val conJType: BType = MethodBType(
classBTypeFromSymbol(definitions.ClassClass) :: stringArrayJType :: stringArrayJType :: Nil,
UNIT
)
def push(lst: List[String]) {
var fi = 0
for (f <- lst) {
constructor.visitInsn(asm.Opcodes.DUP)
constructor.visitLdcInsn(new java.lang.Integer(fi))
if (f == null) { constructor.visitInsn(asm.Opcodes.ACONST_NULL) }
else { constructor.visitLdcInsn(f) }
constructor.visitInsn(StringReference.typedOpcode(asm.Opcodes.IASTORE))
fi += 1
}
}
constructor.visitCode()
constructor.visitVarInsn(asm.Opcodes.ALOAD, 0)
// push the class
constructor.visitLdcInsn(classBTypeFromSymbol(cls).toASMType)
// push the string array of field information
constructor.visitLdcInsn(new java.lang.Integer(fieldList.length))
constructor.visitTypeInsn(asm.Opcodes.ANEWARRAY, StringReference.internalName)
push(fieldList)
// push the string array of method information
constructor.visitLdcInsn(new java.lang.Integer(methodList.length))
constructor.visitTypeInsn(asm.Opcodes.ANEWARRAY, StringReference.internalName)
push(methodList)
// invoke the superclass constructor, which will do the
// necessary java reflection and create Method objects.
constructor.visitMethodInsn(asm.Opcodes.INVOKESPECIAL, "scala/beans/ScalaBeanInfo", INSTANCE_CONSTRUCTOR_NAME, conJType.descriptor, false)
constructor.visitInsn(asm.Opcodes.RETURN)
constructor.visitMaxs(0, 0) // just to follow protocol, dummy arguments
constructor.visitEnd()
innerClassBufferASM ++= classBTypeFromSymbol(cls).info.memberClasses
addInnerClassesASM(beanInfoClass, innerClassBufferASM.toList)
beanInfoClass.visitEnd()
beanInfoClass
}
} // end of class JBeanInfoBuilder
trait JAndroidBuilder {
self: BCInnerClassGen =>
/* From the reference documentation of the Android SDK:
* The `Parcelable` interface identifies classes whose instances can be written to and restored from a `Parcel`.
* Classes implementing the `Parcelable` interface must also have a static field called `CREATOR`,
* which is an object implementing the `Parcelable.Creator` interface.
*/
val androidFieldName = newTermName("CREATOR")
/*
* must-single-thread
*/
def isAndroidParcelableClass(sym: Symbol) =
(AndroidParcelableInterface != NoSymbol) &&
(sym.parentSymbols contains AndroidParcelableInterface)
/*
* must-single-thread
*/
def legacyAddCreatorCode(clinit: asm.MethodVisitor, cnode: asm.tree.ClassNode, thisName: String) {
// this tracks the inner class in innerClassBufferASM, if needed.
val androidCreatorType = getClassBTypeAndRegisterInnerClass(AndroidCreatorClass)
val tdesc_creator = androidCreatorType.descriptor
cnode.visitField(
GenBCode.PublicStaticFinal,
"CREATOR",
tdesc_creator,
null, // no java-generic-signature
null // no initial value
).visitEnd()
val moduleName = (thisName + "$")
// GETSTATIC `moduleName`.MODULE$ : `moduleName`;
clinit.visitFieldInsn(
asm.Opcodes.GETSTATIC,
moduleName,
strMODULE_INSTANCE_FIELD,
"L" + moduleName + ";"
)
// INVOKEVIRTUAL `moduleName`.CREATOR() : android.os.Parcelable$Creator;
val bt = MethodBType(Nil, androidCreatorType)
clinit.visitMethodInsn(
asm.Opcodes.INVOKEVIRTUAL,
moduleName,
"CREATOR",
bt.descriptor,
false
)
// PUTSTATIC `thisName`.CREATOR;
clinit.visitFieldInsn(
asm.Opcodes.PUTSTATIC,
thisName,
"CREATOR",
tdesc_creator
)
}
} // end of trait JAndroidBuilder
}