Scala example source code file (BCodeHelpers.scala)
The BCodeHelpers.scala Scala example source code
/* 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.annotation.switch
import scala.collection.{ immutable, 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 BCodeTypes with BytecodeWriters {
import global._
/*
* 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 =>
cunit.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
// -----------------------------------------------------------------------------------------
/*
* can-multi-thread
*/
def firstCommonSuffix(as: List[Tracked], bs: List[Tracked]): BType = {
var chainA = as
var chainB = bs
var fcs: Tracked = null
do {
if (chainB contains chainA.head) fcs = chainA.head
else if (chainA contains chainB.head) fcs = chainB.head
else {
chainA = chainA.tail
chainB = chainB.tail
}
} while (fcs == null)
fcs.c
}
/* 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 re-entrant because chrs never grows during its operation (that's because all TypeNames being looked up have already been entered).
* To stress this point, rather than using `newTypeName()` we use `lookupTypeName()`
*
* can-multi-thread
*/
override def getCommonSuperClass(inameA: String, inameB: String): String = {
val a = brefType(lookupTypeName(inameA.toCharArray))
val b = brefType(lookupTypeName(inameB.toCharArray))
val lca = jvmWiseLUB(a, b)
val lcaName = lca.getInternalName // don't call javaName because that side-effects innerClassBuffer.
assert(lcaName != "scala/Any")
lcaName // ASM caches the answer during the lifetime of a ClassWriter. We outlive that. Not sure whether caching on our side would improve things.
}
}
/*
* Finding the least upper bound in agreement with the bytecode verifier (given two internal names handed out 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
*
* can-multi-thread
*/
def jvmWiseLUB(a: BType, b: BType): BType = {
assert(a.isNonSpecial, s"jvmWiseLUB() received a non-plain-class $a")
assert(b.isNonSpecial, s"jvmWiseLUB() received a non-plain-class $b")
val ta = exemplars.get(a)
val tb = exemplars.get(b)
val res = (ta.isInterface, tb.isInterface) match {
case (true, true) =>
// exercised by test/files/run/t4761.scala
if (tb.isSubtypeOf(ta.c)) ta.c
else if (ta.isSubtypeOf(tb.c)) tb.c
else ObjectReference
case (true, false) =>
if (tb.isSubtypeOf(a)) a else ObjectReference
case (false, true) =>
if (ta.isSubtypeOf(b)) b else ObjectReference
case _ =>
firstCommonSuffix(ta :: ta.superClasses, tb :: tb.superClasses)
}
assert(res.isNonSpecial, "jvmWiseLUB() returned a non-plain-class.")
res
}
/*
* must-single-thread
*/
object isJavaEntryPoint {
/*
* must-single-thread
*/
def apply(sym: Symbol, csymCompUnit: CompilationUnit): Boolean = {
def fail(msg: String, pos: Position = sym.pos) = {
csymCompUnit.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: ${settings.mainClass.value}")
new DirectToJarfileWriter(f.file)
case _ => factoryNonJarBytecodeWriter()
}
}
/*
* must-single-thread
*/
def fieldSymbols(cls: Symbol): List[Symbol] = {
for (f <- cls.info.decls.toList ;
if !f.isMethod && f.isTerm && !f.isModule
) yield f;
}
/*
* can-multi-thread
*/
def methodSymbols(cd: ClassDef): List[Symbol] = {
cd.impl.body collect { case dd: DefDef => dd.symbol }
}
/*
* must-single-thread
*/
def serialVUID(csym: Symbol): Option[Long] = csym getAnnotation definitions.SerialVersionUIDAttr collect {
case AnnotationInfo(_, _, (_, LiteralAnnotArg(const)) :: Nil) => const.longValue
}
/*
* Populates the InnerClasses JVM attribute with `refedInnerClasses`.
* In addition to inner classes mentioned somewhere in `jclass` (where `jclass` is a class file being emitted)
* `refedInnerClasses` should contain those inner classes defined as direct member classes of `jclass`
* but otherwise not mentioned in `jclass`.
*
* `refedInnerClasses` may contain duplicates,
* need not contain the enclosing inner classes of each inner class it lists (those are looked up for consistency).
*
* This method serializes in the InnerClasses JVM attribute in an appropriate order,
* not necessarily that given by `refedInnerClasses`.
*
* can-multi-thread
*/
final def addInnerClassesASM(jclass: asm.ClassVisitor, refedInnerClasses: Iterable[BType]) {
// used to detect duplicates.
val seen = mutable.Map.empty[String, String]
// result without duplicates, not yet sorted.
val result = mutable.Set.empty[InnerClassEntry]
for(s: BType <- refedInnerClasses;
e: InnerClassEntry <- exemplars.get(s).innersChain) {
assert(e.name != null, "saveInnerClassesFor() is broken.") // documentation
val doAdd = seen.get(e.name) match {
// TODO is it ok for prevOName to be null? (Someone should really document the invariants of the InnerClasses bytecode attribute)
case Some(prevOName) =>
// this occurs e.g. when innerClassBuffer contains both class Thread$State, object Thread$State,
// i.e. for them it must be the case that oname == java/lang/Thread
assert(prevOName == e.outerName, "duplicate")
false
case None => true
}
if (doAdd) {
seen += (e.name -> e.outerName)
result += e
}
}
// sorting ensures inner classes are listed after their enclosing class thus satisfying the Eclipse Java compiler
for(e <- result.toList sortBy (_.name.toString)) {
jclass.visitInnerClass(e.name, e.outerName, e.innerName, e.access)
}
} // end of method addInnerClassesASM()
/*
* 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
val emitSource = debugLevel >= 1
val emitLines = debugLevel >= 2
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".
*/
val innerClassBufferASM = mutable.Set.empty[BType]
/*
* Tracks (if needed) the inner class given by `sym`.
*
* must-single-thread
*/
final def internalName(sym: Symbol): String = { asmClassType(sym).getInternalName }
/*
* Tracks (if needed) the inner class given by `sym`.
*
* must-single-thread
*/
final def asmClassType(sym: Symbol): BType = {
assert(
hasInternalName(sym),
{
val msg0 = if (sym.isAbstractType) "An AbstractTypeSymbol (SI-7122) " else "A symbol ";
msg0 + s"has reached the bytecode emitter, for which no JVM-level internal name can be found: ${sym.fullName}"
}
)
val phantOpt = phantomTypeMap.get(sym)
if (phantOpt.isDefined) {
return phantOpt.get
}
val tracked = exemplar(sym)
val tk = tracked.c
if (tracked.isInnerClass) {
innerClassBufferASM += tk
}
tk
}
/*
* Returns the BType for the given type.
* Tracks (if needed) the inner class given by `t`.
*
* must-single-thread
*/
final def toTypeKind(t: Type): BType = {
/* Interfaces have to be handled delicately to avoid introducing spurious errors,
* but if we treat them all as AnyRef we lose too much information.
*/
def newReference(sym0: Symbol): BType = {
assert(!primitiveTypeMap.contains(sym0), "Use primitiveTypeMap instead.")
assert(sym0 != definitions.ArrayClass, "Use arrayOf() instead.")
if (sym0 == definitions.NullClass) return RT_NULL;
if (sym0 == definitions.NothingClass) return RT_NOTHING;
val sym = (
if (!sym0.isPackageClass) sym0
else sym0.info.member(nme.PACKAGE) match {
case NoSymbol => abort(s"SI-5604: Cannot use package as value: ${sym0.fullName}")
case s => abort(s"SI-5604: found package class where package object expected: $s")
}
)
// Can't call .toInterface (at this phase) or we trip an assertion.
// See PackratParser#grow for a method which fails with an apparent mismatch
// between "object PackratParsers$class" and "trait PackratParsers"
if (sym.isImplClass) {
// pos/spec-List.scala is the sole failure if we don't check for NoSymbol
val traitSym = sym.owner.info.decl(tpnme.interfaceName(sym.name))
if (traitSym != NoSymbol) {
// this tracks the inner class in innerClassBufferASM, if needed.
return asmClassType(traitSym)
}
}
assert(hasInternalName(sym), s"Invoked for a symbol lacking JVM internal name: ${sym.fullName}")
assert(!phantomTypeMap.contains(sym), "phantom types not supposed to reach here.")
val tracked = exemplar(sym)
val tk = tracked.c
if (tracked.isInnerClass) {
innerClassBufferASM += tk
}
tk
}
def primitiveOrRefType(sym: Symbol): BType = {
assert(sym != definitions.ArrayClass, "Use primitiveOrArrayOrRefType() instead.")
primitiveTypeMap.getOrElse(sym, newReference(sym))
}
def primitiveOrRefType2(sym: Symbol): BType = {
primitiveTypeMap.get(sym) match {
case Some(pt) => pt
case None =>
sym match {
case definitions.NullClass => RT_NULL
case definitions.NothingClass => RT_NOTHING
case _ if sym.isClass => newReference(sym)
case _ =>
assert(sym.isType, sym) // it must be compiling Array[a]
ObjectReference
}
}
}
import definitions.ArrayClass
// Call to .normalize fixes #3003 (follow type aliases). Otherwise, primitiveOrArrayOrRefType() would return ObjectReference.
t.normalize match {
case ThisType(sym) =>
if (sym == ArrayClass) ObjectReference
else phantomTypeMap.getOrElse(sym, exemplar(sym).c)
case SingleType(_, sym) => primitiveOrRefType(sym)
case _: ConstantType => toTypeKind(t.underlying)
case TypeRef(_, sym, args) =>
if (sym == ArrayClass) arrayOf(toTypeKind(args.head))
else primitiveOrRefType2(sym)
case ClassInfoType(_, _, sym) =>
assert(sym != ArrayClass, "ClassInfoType to ArrayClass!")
primitiveOrRefType(sym)
// !!! Iulian says types which make no sense after erasure should not reach here, which includes the ExistentialType, AnnotatedType, RefinedType.
case ExistentialType(_, t) => toTypeKind(t) // TODO shouldn't get here but the following does: akka-actor/src/main/scala/akka/util/WildcardTree.scala
case AnnotatedType(_, w) => toTypeKind(w) // TODO test/files/jvm/annotations.scala causes an AnnotatedType to reach here.
case RefinedType(parents, _) => parents map toTypeKind reduceLeft jvmWiseLUB
// For sure WildcardTypes shouldn't reach here either, but when debugging such situations this may come in handy.
// case WildcardType => REFERENCE(ObjectClass)
case norm => abort(
s"Unknown type: $t, $norm [${t.getClass}, ${norm.getClass}] TypeRef? ${t.isInstanceOf[TypeRef]}"
)
}
} // end of method toTypeKind()
/*
* must-single-thread
*/
def asmMethodType(msym: Symbol): BType = {
assert(msym.isMethod, s"not a method-symbol: $msym")
val resT: BType =
if (msym.isClassConstructor || msym.isConstructor) BType.VOID_TYPE
else toTypeKind(msym.tpe.resultType);
BType.getMethodType( resT, mkArray(msym.tpe.paramTypes map toTypeKind) )
}
/*
* Returns all direct member inner classes of `csym`,
* thus making sure they get entries in the InnerClasses JVM attribute
* even if otherwise not mentioned in the class being built.
*
* must-single-thread
*/
final def trackMemberClasses(csym: Symbol, lateClosuresBTs: List[BType]): List[BType] = {
val lateInnerClasses = exitingErasure {
for (sym <- List(csym, csym.linkedClassOfClass); memberc <- sym.info.decls.map(innerClassSymbolFor) if memberc.isClass)
yield memberc
}
// as a precaution, do the following outside the above `exitingErasure` otherwise funny internal names might be computed.
val result = for(memberc <- lateInnerClasses) yield {
val tracked = exemplar(memberc)
val memberCTK = tracked.c
assert(tracked.isInnerClass, s"saveInnerClassesFor() says this was no inner-class after all: ${memberc.fullName}")
memberCTK
}
exemplar(csym).directMemberClasses = result
result
}
/*
* Tracks (if needed) the inner class given by `t`.
*
* must-single-thread
*/
final def descriptor(t: Type): String = { toTypeKind(t).getDescriptor }
/*
* Tracks (if needed) the inner class given by `sym`.
*
* must-single-thread
*/
final def descriptor(sym: Symbol): String = { asmClassType(sym).getDescriptor }
} // end of trait BCInnerClassGen
trait BCAnnotGen extends BCInnerClassGen {
import genASM.{ubytesToCharArray, arrEncode}
/*
* 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)
}
}
/* Whether an annotation should be emitted as a Java annotation
* .initialize: if 'annot' is read from pickle, atp might be un-initialized
*
* must-single-thread
*/
private def shouldEmitAnnotation(annot: AnnotationInfo) =
annot.symbol.initialize.isJavaDefined &&
annot.matches(definitions.ClassfileAnnotationClass) &&
annot.args.isEmpty &&
!annot.matches(definitions.DeprecatedAttr)
/*
* 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), true)
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), true)
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), true)
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), true)
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 {
// -----------------------------------------------------------------------------------------
// Static forwarders (related to mirror classes but also present in
// a plain class lacking companion module, for details see `isCandidateForForwarders`).
// -----------------------------------------------------------------------------------------
val ExcludedForwarderFlags = genASM.ExcludedForwarderFlags
/* 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 = 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 = BType.getMethodType(jReturnType, mkArray(paramJavaTypes)).getDescriptor
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.getOpcode(asm.Opcodes.ILOAD), index)
assert(jparamType.sort != BType.METHOD, jparamType)
index += jparamType.getSize
}
mirrorMethod.visitMethodInsn(asm.Opcodes.INVOKEVIRTUAL, moduleName, mirrorMethodName, asmMethodType(m).getDescriptor)
mirrorMethod.visitInsn(jReturnType.getOpcode(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: $conflictingNames")
for (m <- moduleClass.info.membersBasedOnFlags(ExcludedForwarderFlags, symtab.Flags.METHOD)) {
if (m.isType || m.isDeferred || (m.owner eq definitions.ObjectClass) || m.isConstructor)
debuglog(s"No forwarder for '$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(
PublicStaticFinal,
"serialVersionUID",
"J",
null, // no java-generic-signature
new java.lang.Long(id)
).visitEnd()
}
/*
* @param owner internal name of the enclosing class of the class.
*
* @param name the name of the method that contains the class.
* @param methodType the method that contains the class.
*/
case class EnclMethodEntry(owner: String, name: String, methodType: BType)
/*
* @return null if the current class is not internal to a method
*
* Quoting from JVMS 4.7.7 The EnclosingMethod Attribute
* A class must have an EnclosingMethod attribute if and only if it is a local class or an anonymous class.
* A class may have no more than one EnclosingMethod attribute.
*
* must-single-thread
*/
def getEnclosingMethodAttribute(clazz: Symbol): EnclMethodEntry = { // JVMS 4.7.7
def newEEE(eClass: Symbol, m: Symbol) = {
EnclMethodEntry(
internalName(eClass),
m.javaSimpleName.toString,
asmMethodType(m)
)
}
var res: EnclMethodEntry = null
val sym = clazz.originalEnclosingMethod
if (sym.isMethod) {
debuglog(s"enclosing method for $clazz is $sym (in ${sym.enclClass})")
res = newEEE(sym.enclClass, sym)
} else if (clazz.isAnonymousClass) {
val enclClass = clazz.rawowner
assert(enclClass.isClass, enclClass)
val sym = enclClass.primaryConstructor
if (sym == NoSymbol) {
log(s"Ran out of room looking for an enclosing method for $clazz: no constructor here: $enclClass.")
} else {
debuglog(s"enclosing method for $clazz is $sym (in $enclClass)")
res = newEEE(enclClass, sym)
}
}
res
}
} // end of trait BCClassGen
/* basic functionality for class file building of plain, mirror, and beaninfo classes. */
abstract class JBuilder extends BCInnerClassGen {
} // end of class JBuilder
/* functionality for building plain and mirror classes */
abstract class JCommonBuilder
extends JBuilder
with BCAnnotGen
with BCForwardersGen
with BCPickles { }
/* builder of mirror classes */
class JMirrorBuilder extends JCommonBuilder {
private var cunit: CompilationUnit = _
def getCurrentCUnit(): CompilationUnit = cunit;
/* Generate a mirror class for a top-level module. A mirror class is a class
* containing only static methods that forward to the corresponding method
* on the MODULE instance of the given Scala object. It will only be
* generated if there is no companion class: if there is, an attempt will
* instead be made to add the forwarder methods to the companion class.
*
* must-single-thread
*/
def genMirrorClass(modsym: Symbol, cunit: CompilationUnit): asm.tree.ClassNode = {
assert(modsym.companionClass == NoSymbol, modsym)
innerClassBufferASM.clear()
this.cunit = cunit
val moduleName = internalName(modsym) // + "$"
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 */,
JAVA_LANG_OBJECT.getInternalName,
EMPTY_STRING_ARRAY
)
if (emitSource) {
mirrorClass.visitSource("" + cunit.source,
null /* SourceDebugExtension */)
}
val ssa = getAnnotPickle(mirrorName, modsym.companionSymbol)
mirrorClass.visitAttribute(if (ssa.isDefined) pickleMarkerLocal else pickleMarkerForeign)
emitAnnotations(mirrorClass, modsym.annotations ++ ssa)
addForwarders(isRemote(modsym), mirrorClass, mirrorName, modsym)
innerClassBufferASM ++= trackMemberClasses(modsym, Nil /* TODO what about Late-Closure-Classes */ )
addInnerClassesASM(mirrorClass, innerClassBufferASM.toList)
mirrorClass.visitEnd()
("" + modsym.name) // this side-effect is necessary, really.
mirrorClass
}
} // end of class JMirrorBuilder
/* builder of bean info classes */
class JBeanInfoBuilder extends JBuilder {
/*
* Generate a bean info class that describes the given class.
*
* @author Ross Judson (ross.judson@soletta.com)
*
* 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 = mkFlags(
javaFlags(cls),
if (isDeprecated(cls)) asm.Opcodes.ACC_DEPRECATED else 0 // ASM pseudo access flag
)
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 = arrayOf(JAVA_LANG_STRING)
val conJType: BType =
BType.getMethodType(
BType.VOID_TYPE,
Array(exemplar(definitions.ClassClass).c, stringArrayJType, stringArrayJType)
)
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(JAVA_LANG_STRING.getOpcode(asm.Opcodes.IASTORE))
fi += 1
}
}
constructor.visitCode()
constructor.visitVarInsn(asm.Opcodes.ALOAD, 0)
// push the class
constructor.visitLdcInsn(exemplar(cls).c.toASMType)
// push the string array of field information
constructor.visitLdcInsn(new java.lang.Integer(fieldList.length))
constructor.visitTypeInsn(asm.Opcodes.ANEWARRAY, JAVA_LANG_STRING.getInternalName)
push(fieldList)
// push the string array of method information
constructor.visitLdcInsn(new java.lang.Integer(methodList.length))
constructor.visitTypeInsn(asm.Opcodes.ANEWARRAY, JAVA_LANG_STRING.getInternalName)
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.getDescriptor)
constructor.visitInsn(asm.Opcodes.RETURN)
constructor.visitMaxs(0, 0) // just to follow protocol, dummy arguments
constructor.visitEnd()
innerClassBufferASM ++= trackMemberClasses(cls, Nil /* TODO what about Late-Closure-Classes */ )
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 = asmClassType(AndroidCreatorClass)
val tdesc_creator = androidCreatorType.getDescriptor
cnode.visitField(
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 = BType.getMethodType(androidCreatorType, Array.empty[BType])
clinit.visitMethodInsn(
asm.Opcodes.INVOKEVIRTUAL,
moduleName,
"CREATOR",
bt.getDescriptor
)
// PUTSTATIC `thisName`.CREATOR;
clinit.visitFieldInsn(
asm.Opcodes.PUTSTATIC,
thisName,
"CREATOR",
tdesc_creator
)
}
} // end of trait JAndroidBuilder
}
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