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/* NSC -- new scala compiler
* Copyright 2005-2013 LAMP/EPFL
* @author Martin Odersky
*/
package scala.tools.nsc
package backend
package icode
import scala.collection.immutable
/**
* Exception handlers are pieces of code that `handle` exceptions on
* the covered basic blocks. Since Scala's exception handling uses
* pattern matching instead of just class names to identify handlers,
* all our handlers will catch `Throwable` and rely on proper ordering
* in the generated code to preserve nesting.
*/
trait ExceptionHandlers {
self: ICodes =>
import global._
import definitions.{ ThrowableClass }
class ExceptionHandler(val method: IMethod, val label: TermName, val cls: Symbol, val pos: Position) {
def loadExceptionClass = if (cls == NoSymbol) ThrowableClass else cls
private var _startBlock: BasicBlock = _
var finalizer: Finalizer = _
def setStartBlock(b: BasicBlock) = {
_startBlock = b
b.exceptionHandlerStart = true
}
def startBlock = _startBlock
/** The list of blocks that are covered by this exception handler */
var covered: immutable.Set[BasicBlock] = immutable.HashSet.empty[BasicBlock]
def addCoveredBlock(b: BasicBlock): this.type = {
covered = covered + b
this
}
/** Is `b` covered by this exception handler? */
def covers(b: BasicBlock): Boolean = covered(b)
/** The body of this exception handler. May contain 'dead' blocks (which will not
* make it into generated code because linearizers may not include them) */
var blocks: List[BasicBlock] = Nil
def addBlock(b: BasicBlock): Unit = blocks = b :: blocks
override def toString() = "exh_" + label + "(" + cls.simpleName + ")"
/** A standard copy constructor */
def this(other: ExceptionHandler) = {
this(other.method, other.label, other.cls, other.pos)
covered = other.covered
setStartBlock(other.startBlock)
finalizer = other.finalizer
}
def dup: ExceptionHandler = new ExceptionHandler(this)
}
class Finalizer(method: IMethod, label: TermName, pos: Position) extends ExceptionHandler(method, label, NoSymbol, pos) {
override def toString() = "finalizer_" + label
override def dup: Finalizer = new Finalizer(method, label, pos)
}
}
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