Scala example source code file (BCodeBodyBuilder.scala)
The BCodeBodyBuilder.scala Scala example source code/* NSC -- new Scala compiler
* Copyright 2005-2012 LAMP/EPFL
* @author Martin Odersky
*/
package scala
package tools.nsc
package backend
package jvm
import scala.collection.{ mutable, immutable }
import scala.annotation.switch
import scala.tools.asm
/*
*
* @author Miguel Garcia, http://lamp.epfl.ch/~magarcia/ScalaCompilerCornerReloaded/
* @version 1.0
*
*/
abstract class BCodeBodyBuilder extends BCodeSkelBuilder {
import global._
import definitions._
import bCodeICodeCommon._
/*
* Functionality to build the body of ASM MethodNode, except for `synchronized` and `try` expressions.
*/
abstract class PlainBodyBuilder(cunit: CompilationUnit) extends PlainSkelBuilder(cunit) {
import icodes.TestOp
import icodes.opcodes.InvokeStyle
/* If the selector type has a member with the right name,
* it is the host class; otherwise the symbol's owner.
*/
def findHostClass(selector: Type, sym: Symbol) = selector member sym.name match {
case NoSymbol => debuglog(s"Rejecting $selector as host class for $sym") ; sym.owner
case _ => selector.typeSymbol
}
/* ---------------- helper utils for generating methods and code ---------------- */
def emit(opc: Int) { mnode.visitInsn(opc) }
def emitZeroOf(tk: BType) {
(tk.sort: @switch) match {
case asm.Type.BOOLEAN => bc.boolconst(false)
case asm.Type.BYTE |
asm.Type.SHORT |
asm.Type.CHAR |
asm.Type.INT => bc.iconst(0)
case asm.Type.LONG => bc.lconst(0)
case asm.Type.FLOAT => bc.fconst(0)
case asm.Type.DOUBLE => bc.dconst(0)
case asm.Type.VOID => ()
case _ => emit(asm.Opcodes.ACONST_NULL)
}
}
/*
* Emits code that adds nothing to the operand stack.
* Two main cases: `tree` is an assignment,
* otherwise an `adapt()` to UNIT is performed if needed.
*/
def genStat(tree: Tree) {
lineNumber(tree)
tree match {
case Assign(lhs @ Select(_, _), rhs) =>
val isStatic = lhs.symbol.isStaticMember
if (!isStatic) { genLoadQualifier(lhs) }
genLoad(rhs, symInfoTK(lhs.symbol))
lineNumber(tree)
fieldStore(lhs.symbol)
case Assign(lhs, rhs) =>
val s = lhs.symbol
val Local(tk, _, idx, _) = locals.getOrMakeLocal(s)
genLoad(rhs, tk)
lineNumber(tree)
bc.store(idx, tk)
case _ =>
genLoad(tree, UNIT)
}
}
def genThrow(expr: Tree): BType = {
val thrownKind = tpeTK(expr)
// `throw null` is valid although scala.Null (as defined in src/libray-aux) isn't a subtype of Throwable.
// Similarly for scala.Nothing (again, as defined in src/libray-aux).
assert(thrownKind.isNullType || thrownKind.isNothingType || exemplars.get(thrownKind).isSubtypeOf(ThrowableReference))
genLoad(expr, thrownKind)
lineNumber(expr)
emit(asm.Opcodes.ATHROW) // ICode enters here into enterIgnoreMode, we'll rely instead on DCE at ClassNode level.
RT_NOTHING // always returns the same, the invoker should know :)
}
/* Generate code for primitive arithmetic operations. */
def genArithmeticOp(tree: Tree, code: Int): BType = {
val Apply(fun @ Select(larg, _), args) = tree
var resKind = tpeTK(larg)
assert(resKind.isNumericType || (resKind == BOOL),
s"$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.genPrimitiveArithmetic(icodes.NOT, resKind)
case _ => abort(s"Unknown unary operation: ${fun.symbol.fullName} code: $code")
}
// binary operation
case rarg :: Nil =>
resKind = maxType(tpeTK(larg), tpeTK(rarg))
if (scalaPrimitives.isShiftOp(code) || scalaPrimitives.isBitwiseOp(code)) {
assert(resKind.isIntegralType || (resKind == BOOL),
s"$resKind incompatible with arithmetic modulo operation.")
}
genLoad(larg, resKind)
genLoad(rarg, // check .NET size of shift arguments!
if (scalaPrimitives.isShiftOp(code)) 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
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.getComponentType
bc.aload(elementType)
}
else if (scalaPrimitives.isArraySet(code)) {
args match {
case a1 :: a2 :: Nil =>
genLoad(a1, INT)
genLoad(a2)
// the following line should really be here, but because of bugs in erasure
// we pretend we generate whatever type is expected from us.
//generatedType = UNIT
bc.astore(elementType)
case _ =>
abort(s"Too many arguments for array set operation: $tree")
}
}
else {
generatedType = INT
emit(asm.Opcodes.ARRAYLENGTH)
}
lineNumber(tree)
generatedType
}
def genLoadIf(tree: If, expectedType: BType): BType = {
val If(condp, thenp, elsep) = tree
val success = new asm.Label
val failure = new asm.Label
val hasElse = !elsep.isEmpty
val postIf = if (hasElse) new asm.Label else failure
genCond(condp, success, failure)
val thenKind = tpeTK(thenp)
val elseKind = if (!hasElse) UNIT else tpeTK(elsep)
def hasUnitBranch = (thenKind == UNIT || elseKind == UNIT)
val resKind = if (hasUnitBranch) UNIT else tpeTK(tree)
markProgramPoint(success)
genLoad(thenp, resKind)
if (hasElse) { bc goTo postIf }
markProgramPoint(failure)
if (hasElse) {
genLoad(elsep, resKind)
markProgramPoint(postIf)
}
resKind
}
def genPrimitiveOp(tree: Apply, expectedType: BType): BType = {
val sym = tree.symbol
val Apply(fun @ Select(receiver, _), _) = tree
val code = scalaPrimitives.getPrimitive(sym, receiver.tpe)
import scalaPrimitives.{isArithmeticOp, isArrayOp, isLogicalOp, isComparisonOp}
if (isArithmeticOp(code)) genArithmeticOp(tree, code)
else if (code == scalaPrimitives.CONCAT) genStringConcat(tree)
else if (code == scalaPrimitives.HASH) genScalaHash(receiver)
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)
// 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: ${tree.pos}"
)
}
def genLoad(tree: Tree) {
genLoad(tree, tpeTK(tree))
}
/* Generate code for trees that produce values on the stack */
def genLoad(tree: Tree, expectedType: BType) {
var generatedType = expectedType
lineNumber(tree)
tree match {
case lblDf : LabelDef => genLabelDef(lblDf, expectedType)
case ValDef(_, nme.THIS, _, _) =>
debuglog("skipping trivial assign to _$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)
if (!isSynth) { // there are case <synthetic> ValDef's emitted by patmat
varsInScope ::= (sym -> currProgramPoint())
}
generatedType = UNIT
case t : If =>
generatedType = genLoadIf(t, expectedType)
case r : Return =>
genReturn(r)
generatedType = expectedType
case t : Try =>
generatedType = genLoadTry(t)
case Throw(expr) =>
generatedType = genThrow(expr)
case New(tpt) =>
abort(s"Unexpected New(${tpt.summaryString}/$tpt) reached GenBCode.\n" +
" Call was genLoad" + ((tree, expectedType)))
case app : Apply =>
generatedType = genApply(app, expectedType)
case ApplyDynamic(qual, args) => sys.error("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)
generatedType =
if (tree.symbol == ArrayClass) ObjectReference
else brefType(thisName) // inner class (if any) for claszSymbol already tracked.
}
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, selector) =>
val sym = tree.symbol
generatedType = symInfoTK(sym)
val hostClass = findHostClass(qualifier.tpe, sym)
debuglog(s"Host class of $sym with qual $qualifier (${qualifier.tpe}) is $hostClass")
val qualSafeToElide = treeInfo isQualifierSafeToElide qualifier
def genLoadQualUnlessElidable() { if (!qualSafeToElide) { genLoadQualifier(tree) } }
if (sym.isModule) {
genLoadQualUnlessElidable()
genLoadModule(tree)
}
else if (sym.isStaticMember) {
genLoadQualUnlessElidable()
fieldLoad(sym, hostClass)
}
else {
genLoadQualifier(tree)
fieldLoad(sym, hostClass)
}
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 = RT_NULL
case _ => genConstant(value); generatedType = tpeTK(tree)
}
case blck : Block => genBlock(blck, expectedType)
case Typed(Super(_, _), _) => genLoad(This(claszSymbol), expectedType)
case Typed(expr, _) => genLoad(expr, expectedType)
case Assign(_, _) =>
generatedType = UNIT
genStat(tree)
case av : ArrayValue =>
generatedType = genArrayValue(av)
case mtch : Match =>
generatedType = genMatch(mtch)
case EmptyTree => if (expectedType != UNIT) { emitZeroOf(expectedType) }
case _ => abort(s"Unexpected tree in genLoad: $tree/${tree.getClass} at: ${tree.pos}")
}
// emit conversion
if (generatedType != expectedType) {
adapt(generatedType, expectedType)
}
} // end of GenBCode.genLoad()
// ---------------- field load and store ----------------
/*
* must-single-thread
*/
def fieldLoad( field: Symbol, hostClass: Symbol = null) {
fieldOp(field, isLoad = true, hostClass)
}
/*
* must-single-thread
*/
def fieldStore(field: Symbol, hostClass: Symbol = null) {
fieldOp(field, isLoad = false, hostClass)
}
/*
* must-single-thread
*/
private def fieldOp(field: Symbol, isLoad: Boolean, hostClass: Symbol) {
// LOAD_FIELD.hostClass , CALL_METHOD.hostClass , and #4283
val owner =
if (hostClass == null) internalName(field.owner)
else internalName(hostClass)
val fieldJName = field.javaSimpleName.toString
val fieldDescr = symInfoTK(field).getDescriptor
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) {
(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 toPush: BType = {
val kind = toTypeKind(const.typeValue)
if (kind.isValueType) classLiteral(kind)
else kind
}
mnode.visitLdcInsn(toPush.toASMType)
case EnumTag =>
val sym = const.symbolValue
val ownerName = internalName(sym.owner)
val fieldName = sym.javaSimpleName.toString
val fieldDesc = toTypeKind(sym.tpe.underlying).getDescriptor
mnode.visitFieldInsn(
asm.Opcodes.GETSTATIC,
ownerName,
fieldName,
fieldDesc
)
case _ => abort(s"Unknown constant value: $const")
}
}
private def genLabelDef(lblDf: LabelDef, expectedType: BType) {
// 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).
markProgramPoint(programPoint(lblDf.symbol))
lineNumber(lblDf)
genLoad(lblDf.rhs, expectedType)
}
private def genReturn(r: Return) {
val Return(expr) = r
val returnedKind = tpeTK(expr)
genLoad(expr, returnedKind)
adapt(returnedKind, returnType)
val saveReturnValue = (returnType != UNIT)
lineNumber(r)
cleanups match {
case Nil =>
// not an assertion: !shouldEmitCleanup (at least not yet, pendingCleanups() may still have to run, and reset `shouldEmitCleanup`.
bc emitRETURN returnType
case nextCleanup :: rest =>
if (saveReturnValue) {
if (insideCleanupBlock) {
cunit.warning(r.pos, "Return statement found in finally-clause, discarding its return-value in favor of that of a more deeply nested return.")
bc drop returnType
} else {
// 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
val l = tpeTK(obj)
val r = tpeTK(targs.head)
def genTypeApply(): BType = {
genLoadQualifier(fun)
if (l.isValueType && r.isValueType)
genConversion(l, r, cast)
else if (l.isValueType) {
bc drop l
if (cast) {
mnode.visitTypeInsn(asm.Opcodes.NEW, classCastExceptionReference.getInternalName)
bc dup ObjectReference
emit(asm.Opcodes.ATHROW)
} else {
bc boolconst false
}
}
else if (r.isValueType && cast) {
abort(s"Erasure should have added an unboxing operation to prevent this cast. Tree: $app")
}
else if (r.isValueType) {
bc isInstance classLiteral(r)
}
else {
genCast(r, cast)
}
if (cast) r else BOOL
} // end of genTypeApply()
generatedType = genTypeApply()
// 'super' call: Note: since constructors are supposed to
// return an instance of what they construct, we have to take
// special care. On JVM they are 'void', and Scala forbids (syntactically)
// to call super constructors explicitly and/or use their 'returned' value.
// therefore, we can ignore this fact, and generate code that leaves nothing
// on the stack (contrary to what the type in the AST says).
case Apply(fun @ Select(Super(_, mix), _), args) =>
val invokeStyle = icodes.opcodes.SuperCall(mix)
// if (fun.symbol.isConstructor) Static(true) else SuperCall(mix);
mnode.visitVarInsn(asm.Opcodes.ALOAD, 0)
genLoadArguments(args, paramTKs(app))
genCallMethod(fun.symbol, invokeStyle, pos = app.pos)
generatedType = asmMethodType(fun.symbol).getReturnType
// '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.isRefOrArrayType, s"Non reference type cannot be instantiated: $generatedType")
generatedType match {
case arr if generatedType.isArray =>
genLoadArguments(args, paramTKs(app))
val dims = arr.getDimensions
var elemKind = arr.getElementType
val argsSize = args.length
if (argsSize > dims) {
cunit.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 = arrayOf(elemKind)
}
(argsSize : @switch) match {
case 1 => bc newarray elemKind
case _ =>
val descr = ('[' * argsSize) + elemKind.getDescriptor // denotes the same as: arrayN(elemKind, argsSize).getDescriptor
mnode.visitMultiANewArrayInsn(descr, argsSize)
}
case rt if generatedType.hasObjectSort =>
assert(exemplar(ctor.owner).c == rt, s"Symbol ${ctor.owner.fullName} is different from $rt")
mnode.visitTypeInsn(asm.Opcodes.NEW, rt.getInternalName)
bc dup generatedType
genLoadArguments(args, paramTKs(app))
genCallMethod(ctor, icodes.opcodes.Static(onInstance = true))
case _ =>
abort(s"Cannot instantiate $tpt of kind: $generatedType")
}
case Apply(fun @ _, List(expr)) if currentRun.runDefinitions.isBox(fun.symbol) =>
val nativeKind = tpeTK(expr)
genLoad(expr, nativeKind)
val MethodNameAndType(mname, mdesc) = asmBoxTo(nativeKind)
bc.invokestatic(BoxesRunTime.getInternalName, mname, mdesc)
generatedType = boxResultType(fun.symbol) // was toTypeKind(fun.symbol.tpe.resultType)
case Apply(fun @ _, List(expr)) if currentRun.runDefinitions.isUnbox(fun.symbol) =>
genLoad(expr)
val boxType = unboxResultType(fun.symbol) // was toTypeKind(fun.symbol.owner.linkedClassOfClass.tpe)
generatedType = boxType
val MethodNameAndType(mname, mdesc) = asmUnboxTo(boxType)
bc.invokestatic(BoxesRunTime.getInternalName, mname, mdesc)
case app @ Apply(fun, args) =>
val sym = fun.symbol
if (sym.isLabel) { // jump to a label
genLoadLabelArguments(args, labelDef(sym), app.pos)
bc goTo programPoint(sym)
} else if (isPrimitive(sym)) { // primitive method call
generatedType = genPrimitiveOp(app, expectedType)
} else { // normal method call
def genNormalMethodCall() {
val invokeStyle =
if (sym.isStaticMember) icodes.opcodes.Static(onInstance = false)
else if (sym.isPrivate || sym.isClassConstructor) icodes.opcodes.Static(onInstance = true)
else icodes.opcodes.Dynamic;
if (invokeStyle.hasInstance) {
genLoadQualifier(fun)
}
genLoadArguments(args, paramTKs(app))
// In "a couple cases", squirrel away a extra information (hostClass, targetTypeKind). TODO Document what "in a couple cases" refers to.
var hostClass: Symbol = null
var targetTypeKind: BType = null
fun match {
case Select(qual, _) =>
val qualSym = findHostClass(qual.tpe, sym)
if (qualSym == ArrayClass) {
targetTypeKind = tpeTK(qual)
log(s"Stored target type kind for ${sym.fullName} as $targetTypeKind")
}
else {
hostClass = qualSym
if (qual.tpe.typeSymbol != qualSym) {
log(s"Precisified host class for $sym from ${qual.tpe.typeSymbol.fullName} to ${qualSym.fullName}")
}
}
case _ =>
}
if ((targetTypeKind != null) && (sym == definitions.Array_clone) && invokeStyle.isDynamic) {
val target: String = targetTypeKind.getInternalName
bc.invokevirtual(target, "clone", "()Ljava/lang/Object;")
}
else {
genCallMethod(sym, invokeStyle, hostClass, app.pos)
}
} // end of genNormalMethodCall()
genNormalMethodCall()
generatedType = asmMethodType(sym).getReturnType
}
}
generatedType
} // end of genApply()
private def genArrayValue(av: ArrayValue): BType = {
val ArrayValue(tpt @ TypeTree(), elems) = av
val elmKind = tpeTK(tpt)
val generatedType = arrayOf(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 genMatch(tree: Match): BType = {
lineNumber(tree)
genLoad(tree.selector, INT)
val generatedType = tpeTK(tree)
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.
val postMatch = new asm.Label
for (sb <- switchBlocks.reverse) {
val (caseLabel, caseBody) = sb
markProgramPoint(caseLabel)
genLoad(caseBody, generatedType)
bc goTo postMatch
}
markProgramPoint(postMatch)
generatedType
}
def genBlock(tree: Block, expectedType: BType) {
val Block(stats, expr) = tree
val savedScope = varsInScope
varsInScope = Nil
stats foreach genStat
genLoad(expr, expectedType)
val end = currProgramPoint()
if (emitVars) { // add entries to LocalVariableTable JVM attribute
for ((sym, start) <- varsInScope.reverse) { emitLocalVarScope(sym, start, end) }
}
varsInScope = savedScope
}
def adapt(from: BType, to: BType) {
if (!conforms(from, to)) {
to match {
case UNIT => bc drop from
case _ => bc.emitT2T(from, to)
}
} else if (from.isNothingType) {
emit(asm.Opcodes.ATHROW) // ICode enters here into enterIgnoreMode, we'll rely instead on DCE at ClassNode level.
} else if (from.isNullType) {
bc drop from
emit(asm.Opcodes.ACONST_NULL)
}
else (from, to) match {
case (BYTE, LONG) | (SHORT, LONG) | (CHAR, LONG) | (INT, LONG) => bc.emitT2T(INT, LONG)
case _ => ()
}
}
/* Emit code to Load the qualifier of `tree` on top of the stack. */
def genLoadQualifier(tree: Tree) {
lineNumber(tree)
tree match {
case Select(qualifier, _) => genLoad(qualifier)
case _ => abort(s"Unknown qualifier $tree")
}
}
/* Generate code that loads args into label parameters. */
def genLoadLabelArguments(args: List[Tree], lblDef: LabelDef, gotoPos: Position) {
val aps = {
val params: List[Symbol] = lblDef.params.map(_.symbol)
assert(args.length == params.length, s"Wrong number of arguments in call to label at: $gotoPos")
def isTrivial(kv: (Tree, Symbol)) = kv match {
case (This(_), p) if p.name == nme.THIS => true
case (arg @ Ident(_), p) if arg.symbol == p => true
case _ => false
}
(args zip params) filterNot isTrivial
}
// first push *all* arguments. This makes sure muliple uses of the same labelDef-var will all denote the (previous) value.
aps foreach { case (arg, param) => genLoad(arg, locals(param).tk) } // `locals` is known to contain `param` because `genDefDef()` visited `labelDefsAtOrUnder`
// second assign one by one to the LabelDef's variables.
aps.reverse foreach {
case (_, param) =>
// TODO FIXME a "this" param results from tail-call xform. If so, the `else` branch seems perfectly fine. And the `then` branch must be wrong.
if (param.name == nme.THIS) mnode.visitVarInsn(asm.Opcodes.ASTORE, 0)
else locals.store(param)
}
}
def genLoadArguments(args: List[Tree], btpes: List[BType]) {
(args zip btpes) foreach { case (arg, btpe) => genLoad(arg, btpe) }
}
def genLoadModule(tree: Tree): BType = {
val module = (
if (!tree.symbol.isPackageClass) tree.symbol
else tree.symbol.info.member(nme.PACKAGE) match {
case NoSymbol => abort(s"SI-5604: Cannot use package as value: $tree")
case s => abort(s"SI-5604: found package class where package object expected: $tree")
}
)
lineNumber(tree)
genLoadModule(module)
symInfoTK(module)
}
def genLoadModule(module: Symbol) {
def inStaticMethod = methSymbol != null && methSymbol.isStaticMember
if (claszSymbol == module.moduleClass && jMethodName != "readResolve" && !inStaticMethod) {
mnode.visitVarInsn(asm.Opcodes.ALOAD, 0)
} else {
val mbt = symInfoTK(module)
mnode.visitFieldInsn(
asm.Opcodes.GETSTATIC,
mbt.getInternalName /* + "$" */ ,
strMODULE_INSTANCE_FIELD,
mbt.getDescriptor // for nostalgics: toTypeKind(module.tpe).getDescriptor
)
}
}
def genConversion(from: BType, to: BType, cast: Boolean) {
if (cast) { bc.emitT2T(from, to) }
else {
bc drop from
bc boolconst (from == to)
}
}
def genCast(to: BType, cast: Boolean) {
if (cast) { bc checkCast to }
else { bc isInstance to }
}
/* Is the given symbol a primitive operation? */
def isPrimitive(fun: Symbol): Boolean = scalaPrimitives.isPrimitive(fun)
/* Generate coercion denoted by "code" */
def genCoercion(code: Int) {
import scalaPrimitives._
(code: @switch) match {
case B2B | S2S | C2C | I2I | L2L | F2F | D2D => ()
case _ =>
val from = coercionFrom(code)
val to = coercionTo(code)
bc.emitT2T(from, to)
}
}
def genStringConcat(tree: Tree): BType = {
lineNumber(tree)
liftStringConcat(tree) match {
// Optimization for expressions of the form "" + x. We can avoid the StringBuilder.
case List(Literal(Constant("")), arg) =>
genLoad(arg, ObjectReference)
genCallMethod(String_valueOf, icodes.opcodes.Static(onInstance = false))
case concatenations =>
bc.genStartConcat
for (elem <- concatenations) {
val kind = tpeTK(elem)
genLoad(elem, kind)
bc.genStringConcat(kind)
}
bc.genEndConcat
}
StringReference
}
def genCallMethod(method: Symbol, style: InvokeStyle, hostClass0: Symbol = null, pos: Position = NoPosition) {
val siteSymbol = claszSymbol
val hostSymbol = if (hostClass0 == null) method.owner else hostClass0;
val methodOwner = method.owner
// info calls so that types are up to date; erasure may add lateINTERFACE to traits
hostSymbol.info ; methodOwner.info
def needsInterfaceCall(sym: Symbol) = (
sym.isInterface
|| sym.isJavaDefined && sym.isNonBottomSubClass(definitions.ClassfileAnnotationClass)
)
// whether to reference the type of the receiver or
// the type of the method owner
val useMethodOwner = (
style != icodes.opcodes.Dynamic
|| hostSymbol.isBottomClass
|| methodOwner == definitions.ObjectClass
)
val receiver = if (useMethodOwner) methodOwner else hostSymbol
val bmOwner = asmClassType(receiver)
val jowner = bmOwner.getInternalName
val jname = method.javaSimpleName.toString
val bmType = asmMethodType(method)
val mdescr = bmType.getDescriptor
def initModule() {
// we initialize the MODULE$ field immediately after the super ctor
if (!isModuleInitialized &&
jMethodName == INSTANCE_CONSTRUCTOR_NAME &&
jname == INSTANCE_CONSTRUCTOR_NAME &&
isStaticModule(siteSymbol)) {
isModuleInitialized = true
mnode.visitVarInsn(asm.Opcodes.ALOAD, 0)
mnode.visitFieldInsn(
asm.Opcodes.PUTSTATIC,
thisName,
strMODULE_INSTANCE_FIELD,
"L" + thisName + ";"
)
}
}
if (style.isStatic) {
if (style.hasInstance) { bc.invokespecial (jowner, jname, mdescr) }
else { bc.invokestatic (jowner, jname, mdescr) }
}
else if (style.isDynamic) {
if (needsInterfaceCall(receiver)) { bc.invokeinterface(jowner, jname, mdescr) }
else { bc.invokevirtual (jowner, jname, mdescr) }
}
else {
assert(style.isSuper, s"An unknown InvokeStyle: $style")
bc.invokespecial(jowner, jname, mdescr)
initModule()
}
} // end of genCallMethod()
/* Generate the scala ## method. */
def genScalaHash(tree: Tree): BType = {
genLoadModule(ScalaRunTimeModule) // TODO why load ScalaRunTimeModule if ## has InvokeStyle of Static(false) ?
genLoad(tree, ObjectReference)
genCallMethod(hashMethodSym, icodes.opcodes.Static(onInstance = false))
INT
}
/*
* Returns a list of trees that each should be concatenated, from left to right.
* It turns a chained call like "a".+("b").+("c") into a list of arguments.
*/
def liftStringConcat(tree: Tree): List[Tree] = tree match {
case Apply(fun @ Select(larg, method), rarg) =>
if (isPrimitive(fun.symbol) &&
scalaPrimitives.getPrimitive(fun.symbol) == scalaPrimitives.CONCAT)
liftStringConcat(larg) ::: rarg
else
tree :: Nil
case _ =>
tree :: Nil
}
/* Emit code to compare the two top-most stack values using the 'op' operator. */
private def genCJUMP(success: asm.Label, failure: asm.Label, op: TestOp, tk: BType) {
if (tk.isIntSizedType) { // BOOL, BYTE, CHAR, SHORT, or INT
bc.emitIF_ICMP(op, success)
} else if (tk.isRefOrArrayType) { // REFERENCE(_) | ARRAY(_)
bc.emitIF_ACMP(op, success)
} else {
(tk: @unchecked) match {
case LONG => emit(asm.Opcodes.LCMP)
case FLOAT =>
if (op == icodes.LT || op == icodes.LE) emit(asm.Opcodes.FCMPG)
else emit(asm.Opcodes.FCMPL)
case DOUBLE =>
if (op == icodes.LT || op == icodes.LE) emit(asm.Opcodes.DCMPG)
else emit(asm.Opcodes.DCMPL)
}
bc.emitIF(op, success)
}
bc goTo failure
}
/* Emits code to compare (and consume) stack-top and zero using the 'op' operator */
private def genCZJUMP(success: asm.Label, failure: asm.Label, op: TestOp, tk: BType) {
if (tk.isIntSizedType) { // BOOL, BYTE, CHAR, SHORT, or INT
bc.emitIF(op, success)
} else if (tk.isRefOrArrayType) { // REFERENCE(_) | ARRAY(_)
// @unchecked because references aren't compared with GT, GE, LT, LE.
(op : @unchecked) match {
case icodes.EQ => bc emitIFNULL success
case icodes.NE => bc emitIFNONNULL success
}
} else {
(tk: @unchecked) match {
case LONG =>
emit(asm.Opcodes.LCONST_0)
emit(asm.Opcodes.LCMP)
case FLOAT =>
emit(asm.Opcodes.FCONST_0)
if (op == icodes.LT || op == icodes.LE) emit(asm.Opcodes.FCMPG)
else emit(asm.Opcodes.FCMPL)
case DOUBLE =>
emit(asm.Opcodes.DCONST_0)
if (op == icodes.LT || op == icodes.LE) emit(asm.Opcodes.DCMPG)
else emit(asm.Opcodes.DCMPL)
}
bc.emitIF(op, success)
}
bc goTo failure
}
val testOpForPrimitive: Array[TestOp] = Array(
icodes.EQ, icodes.NE, icodes.EQ, icodes.NE, icodes.LT, icodes.LE, icodes.GE, icodes.GT
)
/*
* Generate code for conditional expressions.
* The jump targets success/failure of the test are `then-target` and `else-target` resp.
*/
private def genCond(tree: Tree, success: asm.Label, failure: asm.Label) {
def genComparisonOp(l: Tree, r: Tree, code: Int) {
val op: TestOp = testOpForPrimitive(code - scalaPrimitives.ID)
// special-case reference (in)equality test for null (null eq x, x eq null)
var nonNullSide: Tree = null
if (scalaPrimitives.isReferenceEqualityOp(code) &&
{ nonNullSide = ifOneIsNull(l, r); nonNullSide != null }
) {
genLoad(nonNullSide, ObjectReference)
genCZJUMP(success, failure, op, ObjectReference)
}
else {
val tk = maxType(tpeTK(l), tpeTK(r))
genLoad(l, tk)
genLoad(r, tk)
genCJUMP(success, failure, op, tk)
}
}
def default() = {
genLoad(tree, BOOL)
genCZJUMP(success, failure, icodes.NE, BOOL)
}
lineNumber(tree)
tree match {
case Apply(fun, args) if isPrimitive(fun.symbol) =>
import scalaPrimitives.{ ZNOT, ZAND, ZOR, EQ, getPrimitive }
// lhs and rhs of test
lazy val Select(lhs, _) = fun
val rhs = if (args.isEmpty) EmptyTree else args.head; // args.isEmpty only for ZNOT
def genZandOrZor(and: Boolean) { // TODO WRONG
// reaching "keepGoing" indicates the rhs should be evaluated too (ie not short-circuited).
val keepGoing = new asm.Label
if (and) genCond(lhs, keepGoing, failure)
else genCond(lhs, success, keepGoing)
markProgramPoint(keepGoing)
genCond(rhs, success, failure)
}
getPrimitive(fun.symbol) match {
case ZNOT => genCond(lhs, failure, success)
case ZAND => genZandOrZor(and = true)
case ZOR => genZandOrZor(and = false)
case code =>
// TODO !!!!!!!!!! isReferenceType, in the sense of TypeKind? (ie non-array, non-boxed, non-nothing, may be null)
if (scalaPrimitives.isUniversalEqualityOp(code) && tpeTK(lhs).hasObjectSort) {
// `lhs` has reference type
if (code == EQ) genEqEqPrimitive(lhs, rhs, success, failure)
else genEqEqPrimitive(lhs, rhs, failure, success)
}
else if (scalaPrimitives.isComparisonOp(code))
genComparisonOp(lhs, rhs, code)
else
default
}
case _ => default
}
} // end of genCond()
/*
* Generate the "==" code for object references. It is equivalent of
* if (l eq null) r eq null else l.equals(r);
*
* @param l left-hand-side of the '=='
* @param r right-hand-side of the '=='
*/
def genEqEqPrimitive(l: Tree, r: Tree, success: asm.Label, failure: asm.Label) {
/* True if the equality comparison is between values that require the use of the rich equality
* comparator (scala.runtime.Comparator.equals). This is the case when either side of the
* comparison might have a run-time type subtype of java.lang.Number or java.lang.Character.
* When it is statically known that both sides are equal and subtypes of Number of Character,
* not using the rich equality is possible (their own equals method will do ok.)
*/
val mustUseAnyComparator: Boolean = {
val areSameFinals = l.tpe.isFinalType && r.tpe.isFinalType && (l.tpe =:= r.tpe)
!areSameFinals && platform.isMaybeBoxed(l.tpe.typeSymbol) && platform.isMaybeBoxed(r.tpe.typeSymbol)
}
if (mustUseAnyComparator) {
val equalsMethod: Symbol = {
if (l.tpe <:< BoxedNumberClass.tpe) {
if (r.tpe <:< BoxedNumberClass.tpe) platform.externalEqualsNumNum
else if (r.tpe <:< BoxedCharacterClass.tpe) platform.externalEqualsNumChar
else platform.externalEqualsNumObject
} else platform.externalEquals
}
genLoad(l, ObjectReference)
genLoad(r, ObjectReference)
genCallMethod(equalsMethod, icodes.opcodes.Static(onInstance = false))
genCZJUMP(success, failure, icodes.NE, BOOL)
}
else {
if (isNull(l)) {
// null == expr -> expr eq null
genLoad(r, ObjectReference)
genCZJUMP(success, failure, icodes.EQ, ObjectReference)
} else if (isNull(r)) {
// expr == null -> expr eq null
genLoad(l, ObjectReference)
genCZJUMP(success, failure, icodes.EQ, ObjectReference)
} else if (isNonNullExpr(l)) {
// SI-7852 Avoid null check if L is statically non-null.
genLoad(l, ObjectReference)
genLoad(r, ObjectReference)
genCallMethod(Object_equals, icodes.opcodes.Dynamic)
genCZJUMP(success, failure, icodes.NE, BOOL)
} else {
// l == r -> if (l eq null) r eq null else l.equals(r)
val eqEqTempLocal = locals.makeLocal(AnyRefReference, nme.EQEQ_LOCAL_VAR.toString)
val lNull = new asm.Label
val lNonNull = new asm.Label
genLoad(l, ObjectReference)
genLoad(r, ObjectReference)
locals.store(eqEqTempLocal)
bc dup ObjectReference
genCZJUMP(lNull, lNonNull, icodes.EQ, ObjectReference)
markProgramPoint(lNull)
bc drop ObjectReference
locals.load(eqEqTempLocal)
genCZJUMP(success, failure, icodes.EQ, ObjectReference)
markProgramPoint(lNonNull)
locals.load(eqEqTempLocal)
genCallMethod(Object_equals, icodes.opcodes.Dynamic)
genCZJUMP(success, failure, icodes.NE, BOOL)
}
}
}
def genSynchronized(tree: Apply, expectedType: BType): BType
def genLoadTry(tree: Try): BType
}
}
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