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/* NSC -- new scala compiler
* Copyright 2005-2009 LAMP/EPFL
* @author Martin Odersky
*/
// $Id$
package scala.tools.nsc
package backend
package icode
import java.io.PrintWriter
import scala.collection.mutable.HashMap
import scala.collection.mutable.{Set, HashSet, ListBuffer}
import scala.{Symbol => scala_Symbol}
import scala.tools.nsc.symtab.Flags
trait Members { self: ICodes =>
import global._
/**
* This class represents the intermediate code of a method or
* other multi-block piece of code, like exception handlers.
*/
class Code(label: String, method: IMethod) {
/** The set of all blocks */
val blocks: ListBuffer[BasicBlock] = new ListBuffer
/** The start block of the method */
var startBlock: BasicBlock = null
/** The stack produced by this method */
var producedStack: TypeStack = null
private var currentLabel: Int = 0
private var _touched = false
def touched = _touched
def touched_=(b: Boolean): Unit = if (b) {
blocks foreach (_.touched = true)
_touched = true
} else
_touched = false
// 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);
if (b == startBlock)
assert(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))
for (handler <- method.exh if handler.covers(b))
handler.covered -= b
touched = true
}
/** This methods returns a string representation of the ICode */
override def toString() : String = "ICode '" + label + "'";
/* 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
}
}
/** Represent a class in ICode */
class IClass(val symbol: Symbol) {
var fields: List[IField] = Nil
var methods: List[IMethod] = Nil
var cunit: CompilationUnit = _
var bootstrapClass: Option[String] = None
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.fullNameString
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)
/* determines whether or not this class contains a static ctor. */
def containsStaticCtor: Boolean = methods.exists(_.isStaticCtor)
/* returns this methods static ctor if it has one. */
def lookupStaticCtor: Option[IMethod] = methods.find(_.isStaticCtor)
}
/** Represent a field in ICode */
class IField(val symbol: Symbol) {
}
/**
* 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) {
var code: Code = null
var native = false
/** The list of exception handlers, ordered from innermost to outermost. */
var exh: List[ExceptionHandler] = Nil
var sourceFile: String = _
var returnType: TypeKind = _
var recursive: Boolean = false
/** local variables and method parameters */
var locals: List[Local] = Nil
/** method parameters */
var params: List[Local] = Nil
def setCode(code: Code): IMethod = {
this.code = code;
this
}
def addLocal(l: Local): Local =
locals find (l.==) match {
case Some(loc) => loc
case None =>
locals = l :: locals;
l
}
def addLocals(ls: List[Local]) {
ls foreach addLocal
}
def addParam(p: Local) {
if (!(params contains p)) {
params = p :: params;
locals = p :: locals;
}
}
def addParams(as: List[Local]) {
as foreach addParam
}
def lookupLocal(n: Name): Option[Local] =
locals find ((l) => l.sym.name == n);
def lookupLocal(sym: Symbol): Option[Local] =
locals find ((l) => l.sym == sym);
def addHandler(e: ExceptionHandler) {
exh = e :: exh
}
/** Is this method deferred ('abstract' in Java sense) */
def isDeferred = (
symbol.hasFlag(Flags.DEFERRED) ||
symbol.owner.hasFlag(Flags.INTERFACE) ||
native
);
def isStatic: Boolean = symbol.isStaticMember
/* determines whether or not this method is the class static constructor. */
def isStaticCtor: Boolean = isStatic && symbol.rawname == nme.CONSTRUCTOR
override def toString() = symbol.fullNameString
import opcodes._
def checkLocals: Unit = if (code ne null) {
Console.println("[checking locals of " + this + "]")
for (bb <- code.blocks; i <- bb) i match {
case LOAD_LOCAL(l) =>
if (!this.locals.contains(l))
Console.println("Local " + l + " is not declared in " + this)
case STORE_LOCAL(l) =>
if (!this.locals.contains(l))
Console.println("Local " + l + " is not declared in " + this)
case _ => ()
}
}
/** 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.code ne null) {
import scala.collection.mutable.{Map, HashMap}
val nextBlock: Map[BasicBlock, BasicBlock] = HashMap.empty
for (b <- code.blocks.toList
if b.successors.length == 1;
val 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);
bb.removeLastInstruction
succ.toList foreach { i => bb.emit(i, i.pos) }
code.removeBlock(succ)
nextBlock -= bb
exh foreach { e => e.covered = e.covered - succ }
} while (nextBlock.isDefinedAt(succ))
bb.close
} else
bb = nextBlock.keysIterator.next
}
}
def dump {
val printer = new TextPrinter(new PrintWriter(Console.out, true),
new DumpLinearizer)
printer.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 visbility range. */
var start: Int = _
/** Ending PC for this local's visbility 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.isInstanceOf[Local] &&
other.asInstanceOf[Local].sym == this.sym
);
override def hashCode = sym.hashCode
override def toString(): String = sym.toString()
}
}
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