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Compiler for the Scala Programming Language
/* NSC -- new scala compiler
* Copyright 2005-2013 LAMP/EPFL
* @author Martin Odersky
*/
package scala.tools.nsc
package backend
package icode
import java.io.PrintWriter
import scala.collection.{ mutable, immutable }
import scala.reflect.internal.util.{ SourceFile, NoSourceFile }
import symtab.Flags.{ DEFERRED }
trait ReferenceEquality {
override def hashCode = System.identityHashCode(this)
override def equals(that: Any) = this eq that.asInstanceOf[AnyRef]
}
trait Members {
self: ICodes =>
import global._
object NoCode extends Code(null, "NoCode") {
override def blocksList: List[BasicBlock] = Nil
}
/**
* This class represents the intermediate code of a method or
* other multi-block piece of code, like exception handlers.
*/
class Code(method: IMethod, name: String) {
def this(method: IMethod) = this(method, method.symbol.decodedName.toString.intern)
/** The set of all blocks */
val blocks = mutable.ListBuffer[BasicBlock]()
/** The start block of the method */
var startBlock: BasicBlock = NoBasicBlock
private var currentLabel: Int = 0
private var _touched = false
def blocksList: List[BasicBlock] = blocks.toList
def instructions = blocksList flatMap (_.iterator)
def blockCount = blocks.size
def instructionCount = (blocks map (_.length)).sum
def touched = _touched
def touched_=(b: Boolean): Unit = {
if (b)
blocks foreach (_.touched = true)
_touched = b
}
// Constructor code
startBlock = newBlock
def removeBlock(b: BasicBlock) {
if (settings.debug.value) {
assert(blocks forall (p => !(p.successors contains b)),
"Removing block that is still referenced in method code " + b + "preds: " + b.predecessors
)
assert(b != startBlock || b.successors.length == 1,
"Removing start block with more than one successor."
)
}
if (b == startBlock)
startBlock = b.successors.head
blocks -= b
assert(!blocks.contains(b))
method.exh filter (_ covers b) foreach (_.covered -= b)
touched = true
}
/** This methods returns a string representation of the ICode */
override def toString = "ICode '" + name + "'";
/* Compute a unique new label */
def nextLabel: Int = {
currentLabel += 1
currentLabel
}
/* Create a new block and append it to the list
*/
def newBlock(): BasicBlock = {
touched = true
val block = new BasicBlock(nextLabel, method);
blocks += block;
block
}
}
/** Common interface for IClass/IField/IMethod. */
trait IMember extends Ordered[IMember] {
def symbol: Symbol
def compare(other: IMember) =
if (symbol eq other.symbol) 0
else if (symbol isLess other.symbol) -1
else 1
}
/** Represent a class in ICode */
class IClass(val symbol: Symbol) extends IMember {
var fields: List[IField] = Nil
var methods: List[IMethod] = Nil
var cunit: CompilationUnit = _
def addField(f: IField): this.type = {
fields = f :: fields;
this
}
def addMethod(m: IMethod): this.type = {
methods = m :: methods;
this
}
def setCompilationUnit(unit: CompilationUnit): this.type = {
this.cunit = unit;
this
}
override def toString() = symbol.fullName
def lookupField(s: Symbol) = fields find (_.symbol == s)
def lookupMethod(s: Symbol) = methods find (_.symbol == s)
def lookupMethod(s: Name) = methods find (_.symbol.name == s)
/* returns this methods static ctor if it has one. */
def lookupStaticCtor: Option[IMethod] = methods find (_.symbol.isStaticConstructor)
}
/** Represent a field in ICode */
class IField(val symbol: Symbol) extends IMember { }
object NoIMethod extends IMethod(NoSymbol) { }
/**
* Represents a method in ICode. Local variables contain
* both locals and parameters, similar to the way the JVM
* 'sees' them.
*
* Locals and parameters are added in reverse order, as they
* are kept in cons-lists. The 'builder' is responsible for
* reversing them and putting them back, when the generation is
* finished (GenICode does that).
*/
class IMethod(val symbol: Symbol) extends IMember {
var code: Code = NoCode
def newBlock() = code.newBlock
def startBlock = code.startBlock
def lastBlock = { assert(blocks.nonEmpty, symbol); blocks.last }
def blocks = code.blocksList
def linearizedBlocks(lin: Linearizer = self.linearizer): List[BasicBlock] = lin linearize this
def foreachBlock[U](f: BasicBlock => U): Unit = blocks foreach f
def foreachInstr[U](f: Instruction => U): Unit = foreachBlock(_.toList foreach f)
var native = false
/** The list of exception handlers, ordered from innermost to outermost. */
var exh: List[ExceptionHandler] = Nil
var sourceFile: SourceFile = NoSourceFile
var returnType: TypeKind = _
var recursive: Boolean = false
var bytecodeHasEHs = false // set by ICodeReader only, used by Inliner to prevent inlining (SI-6188)
var bytecodeHasInvokeDynamic = false // set by ICodeReader only, used by Inliner to prevent inlining until we have proper invoke dynamic support
/** local variables and method parameters */
var locals: List[Local] = Nil
/** method parameters */
var params: List[Local] = Nil
def hasCode = code ne NoCode
def setCode(code: Code): IMethod = {
this.code = code;
this
}
def addLocal(l: Local): Local = findOrElse(locals)(_ == l) { locals ::= l ; l }
def addParam(p: Local): Unit =
if (params contains p) ()
else {
params ::= p
locals ::= p
}
def addLocals(ls: List[Local]) = ls foreach addLocal
def addParams(as: List[Local]) = as foreach addParam
def lookupLocal(n: Name): Option[Local] = locals find (_.sym.name == n)
def lookupLocal(sym: Symbol): Option[Local] = locals find (_.sym == sym)
def addHandler(e: ExceptionHandler) = exh ::= e
/** Is this method deferred ('abstract' in Java sense)?
*/
def isAbstractMethod = symbol.isDeferred || symbol.owner.isInterface || native
def isStatic: Boolean = symbol.isStaticMember
override def toString() = symbol.fullName
def matchesSignature(other: IMethod) = {
(symbol.name == other.symbol.name) &&
(params corresponds other.params)(_.kind == _.kind) &&
(returnType == other.returnType)
}
import opcodes._
def checkLocals(): Unit = {
def localsSet = (code.blocks flatMap { bb =>
bb.iterator collect {
case LOAD_LOCAL(l) => l
case STORE_LOCAL(l) => l
}
}).toSet
if (hasCode) {
log("[checking locals of " + this + "]")
locals filterNot localsSet foreach { l =>
log("Local " + l + " is not declared in " + this)
}
}
}
/** Merge together blocks that have a single successor which has a
* single predecessor. Exception handlers are taken into account (they
* might force to break a block of straight line code like that).
*
* This method should be most effective after heavy inlining.
*/
def normalize(): Unit = if (this.hasCode) {
val nextBlock: mutable.Map[BasicBlock, BasicBlock] = mutable.HashMap.empty
for (b <- code.blocks.toList
if b.successors.length == 1;
succ = b.successors.head;
if succ ne b;
if succ.predecessors.length == 1;
if succ.predecessors.head eq b;
if !(exh.exists { (e: ExceptionHandler) =>
(e.covers(succ) && !e.covers(b)) || (e.covers(b) && !e.covers(succ)) })) {
nextBlock(b) = succ
}
var bb = code.startBlock
while (!nextBlock.isEmpty) {
if (nextBlock.isDefinedAt(bb)) {
bb.open
var succ = bb
do {
succ = nextBlock(succ);
val lastInstr = bb.lastInstruction
/* Ticket SI-5672
* Besides removing the control-flow instruction at the end of `bb` (usually a JUMP), we have to pop any values it pushes.
* Examples:
* `SWITCH` consisting of just the default case, or
* `CJUMP(targetBlock, targetBlock, _, _)` ie where success and failure targets coincide (this one consumes two stack values).
*/
val oldTKs = lastInstr.consumedTypes
assert(lastInstr.consumed == oldTKs.size, "Someone forgot to override consumedTypes() in " + lastInstr)
bb.removeLastInstruction
for(tk <- oldTKs.reverse) { bb.emit(DROP(tk), lastInstr.pos) }
succ.toList foreach { i => bb.emit(i, i.pos) }
code.removeBlock(succ)
exh foreach { e => e.covered = e.covered - succ }
nextBlock -= bb
} while (nextBlock.isDefinedAt(succ))
bb.close
} else
bb = nextBlock.keysIterator.next
}
checkValid(this)
}
def dump() {
Console.println("dumping IMethod(" + symbol + ")")
newTextPrinter() printMethod this
}
}
/** Represent local variables and parameters */
class Local(val sym: Symbol, val kind: TypeKind, val arg: Boolean) {
var index: Int = -1
/** Starting PC for this local's visibility range. */
var start: Int = _
/** Ending PC for this local's visibility range. */
var end: Int = _
/** PC-based ranges for this local variable's visibility */
var ranges: List[(Int, Int)] = Nil
override def equals(other: Any): Boolean = other match {
case x: Local => sym == x.sym
case _ => false
}
override def hashCode = sym.hashCode
override def toString(): String = sym.toString
}
}