/
BCodeBodyBuilder.scala
1704 lines (1495 loc) · 70.8 KB
/
BCodeBodyBuilder.scala
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/*
* Scala (https://www.scala-lang.org)
*
* Copyright EPFL and Lightbend, Inc.
*
* Licensed under Apache License 2.0
* (http://www.apache.org/licenses/LICENSE-2.0).
*
* See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
package scala.tools.nsc
package backend.jvm
import scala.annotation.{ switch, tailrec }
import scala.collection.mutable.ListBuffer
import scala.reflect.internal.Flags
import scala.tools.asm
import scala.tools.asm.Opcodes
import scala.tools.asm.tree.{ InvokeDynamicInsnNode, MethodInsnNode, MethodNode }
import scala.tools.nsc.backend.jvm.BCodeHelpers.{ InvokeStyle, TestOp }
import scala.tools.nsc.backend.jvm.BackendReporting._
import scala.tools.nsc.backend.jvm.GenBCode._
/*
*
* @author Miguel Garcia, https://lampwww.epfl.ch/~magarcia/ScalaCompilerCornerReloaded/
*
*/
abstract class BCodeBodyBuilder extends BCodeSkelBuilder {
import global._
import bTypes._
import coreBTypes._
import definitions._
import genBCode.postProcessor.backendUtils.{addIndyLambdaImplMethod, classfileVersion}
import genBCode.postProcessor.callGraph.{inlineAnnotatedCallsites, noInlineAnnotatedCallsites}
/*
* Functionality to build the body of ASM MethodNode, except for `synchronized` and `try` expressions.
*/
abstract class PlainBodyBuilder(cunit: CompilationUnit) extends PlainSkelBuilder(cunit) {
/* ---------------- helper utils for generating methods and code ---------------- */
def emit(opc: Int): Unit = { mnode.visitInsn(opc) }
def emitZeroOf(tk: BType): Unit = {
tk match {
case BOOL => bc.boolconst(false)
case BYTE |
SHORT |
CHAR |
INT => bc.iconst(0)
case LONG => bc.lconst(0)
case FLOAT => bc.fconst(0)
case DOUBLE => bc.dconst(0)
case UNIT => ()
case _ => emit(asm.Opcodes.ACONST_NULL)
}
}
/*
* Emits code that adds nothing to the operand stack.
* Two main cases: `tree` is an assignment,
* otherwise an `adapt()` to UNIT is performed if needed.
*/
def genStat(tree: Tree): Unit = {
lineNumber(tree)
tree match {
case Assign(lhs @ Select(qual, _), rhs) =>
val isStatic = lhs.symbol.isStaticMember
if (!isStatic) { genLoadQualifier(lhs) }
genLoad(rhs, symInfoTK(lhs.symbol))
lineNumber(tree)
// receiverClass is used in the bytecode to access the field. using sym.owner may lead to IllegalAccessError, scala/bug#4283
val receiverClass = qual.tpe.typeSymbol
fieldStore(lhs.symbol, receiverClass)
case Assign(lhs, rhs) =>
val s = lhs.symbol
val Local(tk, _, idx, _) = locals.getOrMakeLocal(s)
rhs match {
case Apply(Select(larg: Ident, nme.ADD), Literal(x) :: Nil)
if larg.symbol == s && tk.isIntSizedType && x.isShortRange =>
lineNumber(tree)
bc.iinc(idx, x.intValue)
case Apply(Select(larg: Ident, nme.SUB), Literal(x) :: Nil)
if larg.symbol == s && tk.isIntSizedType && Constant(-x.intValue).isShortRange =>
lineNumber(tree)
bc.iinc(idx, -x.intValue)
case _ =>
genLoad(rhs, tk)
lineNumber(tree)
bc.store(idx, tk)
}
case _ =>
genLoad(tree, UNIT)
}
}
/* Generate code for primitive arithmetic operations. */
def genArithmeticOp(tree: Tree, code: Int): BType = {
val Apply(fun @ Select(larg, _), args) = tree: @unchecked
var resKind = tpeTK(larg)
assert(resKind.isNumericType || (resKind == BOOL),
s"$resKind is not a numeric or boolean type [operation: ${fun.symbol}]")
import scalaPrimitives._
args match {
// unary operation
case Nil =>
genLoad(larg, resKind)
code match {
case POS => () // nothing
case NEG => bc.neg(resKind)
case NOT => bc.genPrimitiveNot(resKind)
case _ => abort(s"Unknown unary operation: ${fun.symbol.fullName} code: $code")
}
// binary operation
case rarg :: Nil =>
val isShiftOp = scalaPrimitives.isShiftOp(code)
resKind = tpeTK(larg).maxType(if (isShiftOp) INT else tpeTK(rarg))
if (isShiftOp || scalaPrimitives.isBitwiseOp(code)) {
assert(resKind.isIntegralType || (resKind == BOOL),
s"$resKind incompatible with arithmetic modulo operation.")
}
genLoad(larg, resKind)
genLoad(rarg, if (isShiftOp) INT else resKind)
(code: @switch) match {
case ADD => bc add resKind
case SUB => bc sub resKind
case MUL => bc mul resKind
case DIV => bc div resKind
case MOD => bc rem resKind
case OR | XOR | AND => bc.genPrimitiveLogical(code, resKind)
case LSL | LSR | ASR => bc.genPrimitiveShift(code, resKind)
case _ => abort(s"Unknown primitive: ${fun.symbol}[$code]")
}
case _ =>
abort(s"Too many arguments for primitive function: $tree")
}
lineNumber(tree)
resKind
}
/* Generate primitive array operations. */
def genArrayOp(tree: Tree, code: Int, expectedType: BType): BType = {
val Apply(Select(arrayObj, _), args) = tree: @unchecked
val k = tpeTK(arrayObj)
genLoad(arrayObj, k)
val elementType = typeOfArrayOp.getOrElse(code, abort(s"Unknown operation on arrays: $tree code: $code"))
var generatedType = expectedType
if (scalaPrimitives.isArrayGet(code)) {
// load argument on stack
assert(args.length == 1, s"Too many arguments for array get operation: $tree")
genLoad(args.head, INT)
generatedType = k.asArrayBType.componentType
bc.aload(elementType)
} else if (scalaPrimitives.isArraySet(code)) {
val List(a1, a2) = args: @unchecked
genLoad(a1, INT)
genLoad(a2, elementType)
generatedType = UNIT
bc.astore(elementType)
} else {
generatedType = INT
emit(asm.Opcodes.ARRAYLENGTH)
}
lineNumber(tree)
generatedType
}
def genLoadIfTo(tree: If, expectedType: BType, dest: LoadDestination): BType = {
val If(condp, thenp, elsep) = tree
val success = new asm.Label
val failure = new asm.Label
val hasElse = !elsep.isEmpty
genCond(condp, success, failure, targetIfNoJump = success)
markProgramPoint(success)
if (dest == LoadDestination.FallThrough) {
if (hasElse) {
val thenKind = tpeTK(thenp)
val elseKind = tpeTK(elsep)
def hasUnitBranch = (thenKind == UNIT || elseKind == UNIT)
val resKind = if (hasUnitBranch) UNIT else tpeTK(tree)
val postIf = new asm.Label
genLoadTo(thenp, resKind, LoadDestination.Jump(postIf))
markProgramPoint(failure)
genLoadTo(elsep, resKind, LoadDestination.FallThrough)
markProgramPoint(postIf)
resKind
} else {
genLoad(thenp, UNIT)
markProgramPoint(failure)
UNIT
}
} else {
genLoadTo(thenp, expectedType, dest)
markProgramPoint(failure)
if (hasElse)
genLoadTo(elsep, expectedType, dest)
else
genAdaptAndSendToDest(UNIT, expectedType, dest)
expectedType
}
}
def genPrimitiveOp(tree: Apply, expectedType: BType): BType = {
val sym = tree.symbol
val Apply(fun @ Select(receiver, _), _) = tree: @unchecked
val code = scalaPrimitives.getPrimitive(sym, receiver.tpe)
import scalaPrimitives.{isArithmeticOp, isArrayOp, isComparisonOp, isLogicalOp}
if (isArithmeticOp(code)) genArithmeticOp(tree, code)
else if (code == scalaPrimitives.CONCAT) genStringConcat(tree)
else if (code == scalaPrimitives.HASH) genScalaHash(receiver, tree.pos)
else if (isArrayOp(code)) genArrayOp(tree, code, expectedType)
else if (isLogicalOp(code) || isComparisonOp(code)) {
val success, failure, after = new asm.Label
genCond(tree, success, failure, targetIfNoJump = success)
// success block
markProgramPoint(success)
bc boolconst true
bc goTo after
// failure block
markProgramPoint(failure)
bc boolconst false
// after
markProgramPoint(after)
BOOL
}
else if (code == scalaPrimitives.SYNCHRONIZED)
genSynchronized(tree, expectedType)
else if (scalaPrimitives.isCoercion(code)) {
genLoad(receiver)
lineNumber(tree)
genCoercion(code)
coercionTo(code)
}
else abort(
s"Primitive operation not handled yet: ${sym.fullName}(${fun.symbol.simpleName}) at: ${tree.pos}"
)
}
def genLoad(tree: Tree): Unit = {
genLoad(tree, tpeTK(tree))
}
/* Generate code for trees that produce values on the stack */
def genLoad(tree: Tree, expectedType: BType): Unit =
genLoadTo(tree, expectedType, LoadDestination.FallThrough)
/* Generate code for trees that produce values, sent to a given `LoadDestination`. */
def genLoadTo(tree: Tree, expectedType: BType, dest: LoadDestination): Unit = {
var generatedType = expectedType
var generatedDest: LoadDestination = LoadDestination.FallThrough
lineNumber(tree)
tree match {
case lblDf : LabelDef =>
genLabelDefTo(lblDf, expectedType, dest)
generatedDest = dest
case ValDef(_, nme.THIS, _, _) =>
debuglog(s"skipping trivial assign to ${nme.THIS}: $tree")
case ValDef(_, _, _, rhs) =>
val sym = tree.symbol
/* most of the time, !locals.contains(sym), unless the current activation of genLoad() is being called
while duplicating a finalizer that contains this ValDef. */
val Local(tk, _, idx, isSynth) = locals.getOrMakeLocal(sym)
if (rhs == EmptyTree) { emitZeroOf(tk) }
else { genLoad(rhs, tk) }
bc.store(idx, tk)
val localVarStart = currProgramPoint()
if (!isSynth) { // there are case <synthetic> ValDef's emitted by patmat
varsInScope ::= (sym -> localVarStart)
}
generatedType = UNIT
case t : If =>
generatedType = genLoadIfTo(t, expectedType, dest)
generatedDest = dest
case r : Return =>
genReturn(r)
generatedDest = LoadDestination.Return
case t : Try =>
generatedType = genLoadTry(t)
case Throw(expr) =>
val thrownKind = tpeTK(expr)
genLoadTo(expr, thrownKind, LoadDestination.Throw)
generatedDest = LoadDestination.Throw
case New(tpt) =>
abort(s"Unexpected New(${tpt.summaryString}/$tpt) reached GenBCode.\n" +
" Call was genLoad" + ((tree, expectedType)))
case app @ Apply(fun, args) if fun.symbol.isLabel =>
// jump to a label
val sym = fun.symbol
getJumpDestOrCreate(sym) match {
case JumpDestination.Regular(label) =>
val lblDef = labelDef.getOrElse(sym, {
abort("Not found: " + sym + " in " + labelDef)
})
genLoadLabelArguments(args, lblDef, app.pos)
bc goTo label
generatedDest = LoadDestination.Jump(label)
case JumpDestination.LoadArgTo(paramType, jumpDest) =>
assert(args.sizeIs == 1, s"unexpected argument count for LoadArgTo label $sym")
val arg = args.head
genLoadTo(arg, paramType, jumpDest)
generatedDest = jumpDest
}
case app : Apply =>
generatedType = genApply(app, expectedType)
case app @ ApplyDynamic(qual, Literal(Constant(bootstrapMethodRef: Symbol)) :: staticAndDynamicArgs) =>
val numDynamicArgs = qual.symbol.info.params.length
val (staticArgs, dynamicArgs) = staticAndDynamicArgs.splitAt(staticAndDynamicArgs.length - numDynamicArgs)
val bootstrapDescriptor = staticHandleFromSymbol(bootstrapMethodRef)
val bootstrapArgs = staticArgs.map({case t @ Literal(c: Constant) => bootstrapMethodArg(c, t.pos) case x => throw new MatchError(x)})
val descriptor = methodBTypeFromMethodType(qual.symbol.info, isConstructor=false)
genLoadArguments(dynamicArgs, qual.symbol.info.params.map(param => typeToBType(param.info)))
mnode.visitInvokeDynamicInsn(qual.symbol.name.encoded, descriptor.descriptor, bootstrapDescriptor, bootstrapArgs : _*)
case ApplyDynamic(qual, args) => abort("No invokedynamic support yet.")
case This(qual) =>
val symIsModuleClass = tree.symbol.isModuleClass
assert(tree.symbol == claszSymbol || symIsModuleClass,
s"Trying to access the this of another class: tree.symbol = ${tree.symbol}, class symbol = $claszSymbol compilation unit: $cunit")
if (symIsModuleClass && tree.symbol != claszSymbol) {
generatedType = genLoadModule(tree)
}
else {
mnode.visitVarInsn(asm.Opcodes.ALOAD, 0)
// When compiling Array.scala, the constructor invokes `Array.this.super.<init>`. The expectedType
// is `[Object` (computed by typeToBType, the type of This(Array) is `Array[T]`). If we would set
// the generatedType to `Array` below, the call to adapt at the end would fail. The situation is
// similar for primitives (`I` vs `Int`).
if (tree.symbol != ArrayClass && !definitions.isPrimitiveValueClass(tree.symbol)) {
generatedType = classBTypeFromSymbol(claszSymbol)
}
}
case Select(Ident(nme.EMPTY_PACKAGE_NAME), module) =>
assert(tree.symbol.isModule, s"Selection of non-module from empty package: $tree sym: ${tree.symbol} at: ${tree.pos}")
genLoadModule(tree)
case Select(qualifier, _) =>
val sym = tree.symbol
generatedType = symInfoTK(sym)
val qualSafeToElide = treeInfo isQualifierSafeToElide qualifier
def genLoadQualUnlessElidable(): Unit = { if (!qualSafeToElide) { genLoadQualifier(tree, drop = true) } }
// receiverClass is used in the bytecode to access the field. using sym.owner may lead to IllegalAccessError, scala/bug#4283
def receiverClass = qualifier.tpe.typeSymbol
if (sym.isModule) {
genLoadQualUnlessElidable()
genLoadModule(tree)
} else if (sym.isStaticMember) {
genLoadQualUnlessElidable()
fieldLoad(sym, receiverClass)
} else {
genLoadQualifier(tree)
fieldLoad(sym, receiverClass)
}
case Ident(name) =>
val sym = tree.symbol
if (!sym.hasPackageFlag) {
val tk = symInfoTK(sym)
if (sym.isModule) { genLoadModule(tree) }
else { locals.load(sym) }
generatedType = tk
}
case Literal(value) =>
if (value.tag != UnitTag) (value.tag, expectedType) match {
case (IntTag, LONG ) => bc.lconst(value.longValue); generatedType = LONG
case (FloatTag, DOUBLE) => bc.dconst(value.doubleValue); generatedType = DOUBLE
case (NullTag, _ ) => bc.emit(asm.Opcodes.ACONST_NULL); generatedType = srNullRef
case _ => genConstant(value); generatedType = tpeTK(tree)
}
case blck : Block =>
genBlockTo(blck, expectedType, dest)
generatedDest = dest
case Typed(Super(_, _), _) =>
genLoadTo(This(claszSymbol), expectedType, dest)
generatedDest = dest
case Typed(expr, _) =>
genLoadTo(expr, expectedType, dest)
generatedDest = dest
case Assign(_, _) =>
generatedType = UNIT
genStat(tree)
case av : ArrayValue =>
generatedType = genArrayValue(av)
case mtch : Match =>
generatedType = genMatchTo(mtch, expectedType, dest)
generatedDest = dest
case EmptyTree => if (expectedType != UNIT) { emitZeroOf(expectedType) }
case _ => abort(s"Unexpected tree in genLoad: $tree/${tree.getClass} at: ${tree.pos}")
}
// emit conversion and send to the right destination
if (generatedDest == LoadDestination.FallThrough)
genAdaptAndSendToDest(generatedType, expectedType, dest)
} // end of GenBCode.genLoad()
def genAdaptAndSendToDest(generatedType: BType, expectedType: BType, dest: LoadDestination): Unit = {
if (generatedType != expectedType)
adapt(generatedType, expectedType)
dest match {
case LoadDestination.FallThrough =>
()
case LoadDestination.Jump(label) =>
bc goTo label
case LoadDestination.Return =>
bc emitRETURN returnType
case LoadDestination.Throw =>
val thrownKind = expectedType
// `throw null` is valid although scala.Null (as defined in src/library-aux) isn't a subtype of Throwable.
// Similarly for scala.Nothing (again, as defined in src/library-aux).
assert(thrownKind.isNullType || thrownKind.isNothingType || thrownKind.asClassBType.isSubtypeOf(jlThrowableRef).get, "Require throwable")
emit(asm.Opcodes.ATHROW)
}
}
// ---------------- field load and store ----------------
/*
* must-single-thread
*/
def fieldLoad(field: Symbol, hostClass: Symbol): Unit = fieldOp(field, isLoad = true, hostClass)
/*
* must-single-thread
*/
def fieldStore(field: Symbol, hostClass: Symbol): Unit = fieldOp(field, isLoad = false, hostClass)
/*
* must-single-thread
*/
private def fieldOp(field: Symbol, isLoad: Boolean, hostClass: Symbol): Unit = {
val owner = internalName(if (hostClass == null) field.owner else hostClass)
val fieldJName = field.javaSimpleName.toString
val fieldDescr = symInfoTK(field).descriptor
val isStatic = field.isStaticMember
val opc =
if (isLoad) { if (isStatic) asm.Opcodes.GETSTATIC else asm.Opcodes.GETFIELD }
else { if (isStatic) asm.Opcodes.PUTSTATIC else asm.Opcodes.PUTFIELD }
mnode.visitFieldInsn(opc, owner, fieldJName, fieldDescr)
}
// ---------------- emitting constant values ----------------
/*
* For const.tag in {ClazzTag, EnumTag}
* must-single-thread
* Otherwise it's safe to call from multiple threads.
*/
def genConstant(const: Constant): Unit = {
(const.tag: @switch) match {
case BooleanTag => bc.boolconst(const.booleanValue)
case ByteTag => bc.iconst(const.byteValue)
case ShortTag => bc.iconst(const.shortValue)
case CharTag => bc.iconst(const.charValue)
case IntTag => bc.iconst(const.intValue)
case LongTag => bc.lconst(const.longValue)
case FloatTag => bc.fconst(const.floatValue)
case DoubleTag => bc.dconst(const.doubleValue)
case UnitTag => ()
case StringTag =>
assert(const.value != null, const) // TODO this invariant isn't documented in `case class Constant`
mnode.visitLdcInsn(const.stringValue) // `stringValue` special-cases null, but not for a const with StringTag
case NullTag => emit(asm.Opcodes.ACONST_NULL)
case ClazzTag =>
val tp = typeToBType(const.typeValue)
// classOf[Int] is transformed to Integer.TYPE by CleanUp
assert(!tp.isPrimitive, s"expected class type in classOf[T], found primitive type $tp")
mnode.visitLdcInsn(tp.toASMType)
case EnumTag =>
val sym = const.symbolValue
val ownerName = internalName(sym.owner)
val fieldName = sym.javaSimpleName.toString
val fieldDesc = typeToBType(sym.tpe.underlying).descriptor
mnode.visitFieldInsn(
asm.Opcodes.GETSTATIC,
ownerName,
fieldName,
fieldDesc
)
case _ => abort(s"Unknown constant value: $const")
}
}
private def genLabelDefTo(lblDf: LabelDef, expectedType: BType, dest: LoadDestination): Unit = {
// duplication of LabelDefs contained in `finally`-clauses is handled when emitting RETURN. No bookkeeping for that required here.
// no need to call index() over lblDf.params, on first access that magic happens (moreover, no LocalVariableTable entries needed for them).
// If we get inside genLabelDefTo, no one has or will register a non-regular jump destination for this LabelDef
(getJumpDestOrCreate(lblDf.symbol): @unchecked) match {
case JumpDestination.Regular(label) =>
markProgramPoint(label)
lineNumber(lblDf)
genLoadTo(lblDf.rhs, expectedType, dest)
}
}
private def genReturn(r: Return): Unit = {
val Return(expr) = r
cleanups match {
case Nil =>
// not an assertion: !shouldEmitCleanup (at least not yet, pendingCleanups() may still have to run, and reset `shouldEmitCleanup`.
genLoadTo(expr, returnType, LoadDestination.Return)
case nextCleanup :: rest =>
genLoad(expr, returnType)
lineNumber(r)
val saveReturnValue = (returnType != UNIT)
if (saveReturnValue) {
// regarding return value, the protocol is: in place of a `return-stmt`, a sequence of `adapt, store, jump` are inserted.
if (earlyReturnVar == null) {
earlyReturnVar = locals.makeLocal(returnType, "earlyReturnVar")
}
locals.store(earlyReturnVar)
}
bc goTo nextCleanup
shouldEmitCleanup = true
}
} // end of genReturn()
private def genApply(app: Apply, expectedType: BType): BType = {
var generatedType = expectedType
lineNumber(app)
app match {
case Apply(TypeApply(fun, targs), _) =>
val sym = fun.symbol
val cast = sym match {
case Object_isInstanceOf => false
case Object_asInstanceOf => true
case _ => abort(s"Unexpected type application $fun[sym: ${sym.fullName}] in: $app")
}
val Select(obj, _) = fun: @unchecked
val l = tpeTK(obj)
val r = tpeTK(targs.head)
def genTypeApply(): BType = {
genLoadQualifier(fun)
// TODO @lry make pattern match
if (l.isPrimitive && r.isPrimitive)
genConversion(l, r, cast)
else if (l.isPrimitive) {
bc drop l
if (cast) {
devWarning(s"Tried to emit impossible cast from primitive type $l to $r (at ${app.pos})")
mnode.visitTypeInsn(asm.Opcodes.NEW, jlClassCastExceptionRef.internalName)
bc dup ObjectRef
mnode.visitMethodInsn(asm.Opcodes.INVOKESPECIAL, jlClassCastExceptionRef.internalName, INSTANCE_CONSTRUCTOR_NAME, "()V", true)
emit(asm.Opcodes.ATHROW)
} else {
bc boolconst false
}
}
else if (r.isPrimitive && cast) {
abort(s"Erasure should have added an unboxing operation to prevent this cast. Tree: $app")
}
else if (r.isPrimitive) {
bc isInstance boxedClassOfPrimitive(r.asPrimitiveBType)
}
else {
assert(r.isRef, r) // ensure that it's not a method
genCast(r.asRefBType, cast)
}
if (cast) r else BOOL
} // end of genTypeApply()
generatedType = genTypeApply()
case Apply(fun @ Select(sup @ Super(superQual, _), _), args) =>
// scala/bug#10290: qual can be `this.$outer()` (not just `this`), so we call genLoad (not just ALOAD_0)
genLoad(superQual)
genLoadArguments(args, paramTKs(app))
generatedType = genCallMethod(fun.symbol, InvokeStyle.Super, app.pos, sup.tpe.typeSymbol)
// 'new' constructor call: Note: since constructors are
// thought to return an instance of what they construct,
// we have to 'simulate' it by DUPlicating the freshly created
// instance (on JVM, <init> methods return VOID).
case Apply(fun @ Select(New(tpt), nme.CONSTRUCTOR), args) =>
val ctor = fun.symbol
assert(ctor.isClassConstructor, s"'new' call to non-constructor: ${ctor.name}")
generatedType = tpeTK(tpt)
assert(generatedType.isRef, s"Non reference type cannot be instantiated: $generatedType")
generatedType match {
case arr @ ArrayBType(componentType) =>
genLoadArguments(args, paramTKs(app))
val dims = arr.dimension
var elemKind = arr.elementType
val argsSize = args.length
if (argsSize > dims) {
reporter.error(app.pos, s"too many arguments for array constructor: found ${args.length} but array has only $dims dimension(s)")
}
if (argsSize < dims) {
/* In one step:
* elemKind = new BType(BType.ARRAY, arr.off + argsSize, arr.len - argsSize)
* however the above does not enter a TypeName for each nested arrays in chrs.
*/
for (i <- args.length until dims) elemKind = ArrayBType(elemKind)
}
argsSize match {
case 1 => bc newarray elemKind
case _ => // this is currently dead code in Scalac, unlike in Dotty
val descr = ("[" * argsSize) + elemKind.descriptor // denotes the same as: arrayN(elemKind, argsSize).descriptor
mnode.visitMultiANewArrayInsn(descr, argsSize)
}
case rt: ClassBType =>
assert(classBTypeFromSymbol(ctor.owner) == rt, s"Symbol ${ctor.owner.fullName} is different from $rt")
mnode.visitTypeInsn(asm.Opcodes.NEW, rt.internalName)
bc dup generatedType
genLoadArguments(args, paramTKs(app))
genCallMethod(ctor, InvokeStyle.Special, app.pos)
case _ =>
abort(s"Cannot instantiate $tpt of kind: $generatedType")
}
case Apply(fun, args) if app.hasAttachment[delambdafy.LambdaMetaFactoryCapable] =>
val attachment = app.attachments.get[delambdafy.LambdaMetaFactoryCapable].get
genLoadArguments(args, paramTKs(app))
genInvokeDynamicLambda(attachment)
generatedType = methodBTypeFromSymbol(fun.symbol).returnType
case Apply(fun, expr :: Nil) if currentRun.runDefinitions.isBox(fun.symbol) =>
val nativeKind = typeToBType(fun.symbol.firstParam.info)
genLoad(expr, nativeKind)
val MethodNameAndType(mname, methodType) = srBoxesRuntimeBoxToMethods(nativeKind)
bc.invokestatic(srBoxesRunTimeRef.internalName, mname, methodType.descriptor, itf = false, app.pos)
generatedType = boxResultType(fun.symbol)
case Apply(fun, expr :: Nil) if currentRun.runDefinitions.isUnbox(fun.symbol) =>
genLoad(expr)
val boxType = unboxResultType(fun.symbol)
generatedType = boxType
val MethodNameAndType(mname, methodType) = srBoxesRuntimeUnboxToMethods(boxType)
bc.invokestatic(srBoxesRunTimeRef.internalName, mname, methodType.descriptor, itf = false, app.pos)
case app @ Apply(fun, args) =>
val sym = fun.symbol
if (isPrimitive(sym)) { // primitive method call
generatedType = genPrimitiveOp(app, expectedType)
} else { // normal method call
def isTraitSuperAccessorBodyCall = app.hasAttachment[UseInvokeSpecial.type]
val invokeStyle =
if (sym.isStaticMember)
InvokeStyle.Static
else if (sym.isPrivate || sym.isClassConstructor) InvokeStyle.Special
else if (isTraitSuperAccessorBodyCall)
InvokeStyle.Special
else InvokeStyle.Virtual
if (invokeStyle.hasInstance) genLoadQualifier(fun)
genLoadArguments(args, paramTKs(app))
val Select(qual, _) = fun: @unchecked // fun is a Select, also checked in genLoadQualifier
if (sym == definitions.Array_clone) {
// Special-case Array.clone, introduced in 36ef60e. The goal is to generate this call
// as "[I.clone" instead of "java/lang/Object.clone". This is consistent with javac.
// Arrays have a public method `clone` (jls 10.7).
//
// The JVMS is not explicit about this, but that receiver type can be an array type
// descriptor (instead of a class internal name):
// invokevirtual #2; //Method "[I".clone:()Ljava/lang/Object
//
// Note that using `Object.clone()` would work as well, but only because the JVM
// relaxes protected access specifically if the receiver is an array:
// https://hg.openjdk.java.net/jdk8/jdk8/hotspot/file/87ee5ee27509/src/share/vm/interpreter/linkResolver.cpp#l439
// Example: `class C { override def clone(): Object = "hi" }`
// Emitting `def f(c: C) = c.clone()` as `Object.clone()` gives a VerifyError.
val target: String = tpeTK(qual).asRefBType.classOrArrayType
val methodBType = methodBTypeFromSymbol(sym)
bc.invokevirtual(target, sym.javaSimpleName.toString, methodBType.descriptor, app.pos)
generatedType = methodBType.returnType
} else {
val receiverClass = if (!invokeStyle.isVirtual) null else {
// receiverClass is used in the bytecode to as the method receiver. using sym.owner
// may lead to IllegalAccessErrors, see 9954eaf / aladdin bug 455.
val qualSym = qual.tpe.typeSymbol
if (qualSym == ArrayClass) {
// For invocations like `Array(1).hashCode` or `.wait()`, use Object as receiver
// in the bytecode. Using the array descriptor (like we do for clone above) seems
// to work as well, but it seems safer not to change this. Javac also uses Object.
// Note that array apply/update/length are handled by isPrimitive (above).
assert(sym.owner == ObjectClass, s"unexpected array call: ${show(app)}")
ObjectClass
} else qualSym
}
generatedType = genCallMethod(sym, invokeStyle, app.pos, receiverClass)
// Check if the Apply tree has an InlineAnnotatedAttachment, added by the typer
// for callsites marked `f(): @inline/noinline`. For nullary calls, the attachment
// is on the Select node (not on the Apply node added by UnCurry).
@tailrec
def recordInlineAnnotated(t: Tree): Unit = {
if (t.hasAttachment[InlineAnnotatedAttachment]) lastInsn match {
case m: MethodInsnNode =>
if (t.hasAttachment[NoInlineCallsiteAttachment.type]) noInlineAnnotatedCallsites += m
else inlineAnnotatedCallsites += m
case _ =>
} else t match {
case Apply(fun, _) => recordInlineAnnotated(fun)
case _ =>
}
}
recordInlineAnnotated(app)
}
}
}
generatedType
} // end of genApply()
private def genArrayValue(av: ArrayValue): BType = {
val ArrayValue(tpt @ TypeTree(), elems) = (av: @unchecked)
val elmKind = tpeTK(tpt)
val generatedType = ArrayBType(elmKind)
lineNumber(av)
bc iconst elems.length
bc newarray elmKind
var i = 0
var rest = elems
while (!rest.isEmpty) {
bc dup generatedType
bc iconst i
genLoad(rest.head, elmKind)
bc astore elmKind
rest = rest.tail
i = i + 1
}
generatedType
}
/*
* A Match node contains one or more case clauses,
* each case clause lists one or more Int values to use as keys, and a code block.
* Except the "default" case clause which (if it exists) doesn't list any Int key.
*
* On a first pass over the case clauses, we flatten the keys and their targets (the latter represented with asm.Labels).
* That representation allows JCodeMethodV to emit a lookupswitch or a tableswitch.
*
* On a second pass, we emit the switch blocks, one for each different target.
*/
private def genMatchTo(tree: Match, expectedType: BType, dest: LoadDestination): BType = {
lineNumber(tree)
genLoad(tree.selector, INT)
val (generatedType, postMatch, postMatchDest) = {
if (dest == LoadDestination.FallThrough) {
val postMatch = new asm.Label
(tpeTK(tree), postMatch, LoadDestination.Jump(postMatch))
} else {
(expectedType, null, dest)
}
}
var flatKeys: List[Int] = Nil
var targets: List[asm.Label] = Nil
var default: asm.Label = null
var switchBlocks: List[Tuple2[asm.Label, Tree]] = Nil
// collect switch blocks and their keys, but don't emit yet any switch-block.
for (caze @ CaseDef(pat, guard, body) <- tree.cases) {
assert(guard == EmptyTree, guard)
val switchBlockPoint = new asm.Label
switchBlocks ::= ((switchBlockPoint, body))
pat match {
case Literal(value) =>
flatKeys ::= value.intValue
targets ::= switchBlockPoint
case Ident(nme.WILDCARD) =>
assert(default == null, s"multiple default targets in a Match node, at ${tree.pos}")
default = switchBlockPoint
case Alternative(alts) =>
alts foreach {
case Literal(value) =>
flatKeys ::= value.intValue
targets ::= switchBlockPoint
case _ =>
abort(s"Invalid alternative in alternative pattern in Match node: $tree at: ${tree.pos}")
}
case _ =>
abort(s"Invalid pattern in Match node: $tree at: ${tree.pos}")
}
}
bc.emitSWITCH(mkArrayReverse(flatKeys), mkArray(targets.reverse), default, MIN_SWITCH_DENSITY)
// emit switch-blocks.
for (sb <- switchBlocks.reverse) {
val (caseLabel, caseBody) = sb
markProgramPoint(caseLabel)
genLoadTo(caseBody, generatedType, postMatchDest)
}
if (postMatch != null)
markProgramPoint(postMatch)
generatedType
}
def genBlockTo(tree: Block, expectedType: BType, dest: LoadDestination): Unit = {
val Block(stats, expr) = tree
val savedScope = varsInScope
varsInScope = Nil
/* Optimize common patmat-generated shapes, so that we can push the
* `dest` down the various cases.
*
* The two most common shapes are
*
* {
* initStats
* case1() { ... matchEnd(caseBody1) ... }
* ...
* caseN() { ... matchEnd(caseBodyN) ... }
* matchEnd(x: R) {
* x
* }
* }
*
* for non-unit results, and
*
* {
* initStats
* case1() { ... matchEnd(caseBody1) ... }
* ...
* caseN() { ... matchEnd(caseBodyN) ... }
* matchEnd(x: BoxedUnit$) {
* ()
* }
* }
*
* for unit results.
*
* If we do nothing, when we encounter the calls to `matchEnd` in the
* cases, we don't know yet what is the final `dest` of the block, so we
* cannot generate good code.
*
* Here, we recognize those shapes, and if we find them, we record a
* priori the ultimate `dest` of the full match. This allows to push
* `dest` to all the cases.
*
* For the transformation to be correct, control must not flow into
* `matchEnd` "normally" (i.e., not through a label apply). This is
* always the case for patmat-generated `matchEnd`s, but not for
* arbitrary LabelDefs. In particular, it is not true for
* tailrec-generarted LabelDefs. Therefore, we add specific tests to
* only recognize patmat-generated `matchEnd` labels this way.
*
* It is possible (e.g., in the presence of a compiler plugin) that the
* patmat-generated code gets transformed in a different shape, which we
* would not be able to recognize here. In those cases, the default
* (non-optimal) codegen will apply.
*/
def default(): Unit = {
stats foreach genStat
genLoadTo(expr, expectedType, dest)
}
def optimizedMatch(sym: Symbol): Unit = {
if (dest == LoadDestination.FallThrough) {
val label = new asm.Label
jumpDest += ((sym -> JumpDestination.LoadArgTo(expectedType, LoadDestination.Jump(label))))
stats foreach genStat
markProgramPoint(label)
} else {
jumpDest += ((sym -> JumpDestination.LoadArgTo(expectedType, dest)))
stats foreach genStat
}
}
def isMatchEndLabelDef(tree: LabelDef): Boolean =
treeInfo.hasSynthCaseSymbol(tree) && tree.symbol.name.startsWith("matchEnd")
expr match {
case matchEnd @ LabelDef(_, singleArg :: Nil, body) if isMatchEndLabelDef(matchEnd) =>
val sym = matchEnd.symbol
body match {
case _ if jumpDest.contains(sym) =>
// We already generated a jump to this label in the regular way; we cannot optimize anymore
default()
case bodyIdent: Ident if bodyIdent.symbol == singleArg.symbol =>
optimizedMatch(sym)
case Literal(Constant(())) =>
optimizedMatch(sym)
case _ =>
default()
}
case _ =>
default()
}
emitLocalVarScopes()
varsInScope = savedScope
}
/** Add entries to the `LocalVariableTable` JVM attribute for all the vars in
* `varsInScope`, ending at the current program point.
*/
def emitLocalVarScopes(): Unit = {
if (emitVars) {
val end = currProgramPoint()
for ((sym, start) <- varsInScope.reverse) { emitLocalVarScope(sym, start, end) }
}
}
def adapt(from: BType, to: BType): Unit = {
if (from.isNothingType) {
/* There are two possibilities for from.isNothingType: emitting a "throw e" expressions and
* loading a (phantom) value of type Nothing.
*
* The Nothing type in Scala's type system does not exist in the JVM. In bytecode, Nothing
* is mapped to scala.runtime.Nothing$. To the JVM, a call to Predef.??? looks like it would
* return an object of type Nothing$. We need to do something with that phantom object on
* the stack. "Phantom" because it never exists: such methods always throw, but the JVM does
* not know that.
*
* Note: The two verifiers (old: type inference, new: type checking) have different
* requirements. Very briefly:
*
* Old (https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.10.2.1): at
* each program point, no matter what branches were taken to get there
* - Stack is same size and has same typed values
* - Local and stack values need to have consistent types
* - In practice, the old verifier seems to ignore unreachable code and accept any