/* NSC -- new scala compiler
* Copyright 2005-2008 LAMP/EPFL
* @author Martin Odersky
*/
// $Id$
package scala.tools.nsc.backend.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
// 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
}
/**
* Apply a function to all basic blocks, for side-effects. It starts at
* the given startBlock and checks that are no predecessors of the given node.
* Only blocks that are reachable via a path from startBlock are ever visited.
*/
def traverseFrom(startBlock: BasicBlock, f: BasicBlock => Unit) = {
val visited: Set[BasicBlock] = new HashSet();
def traverse0(toVisit: List[BasicBlock]): Unit = toVisit match {
case Nil => ();
case b :: bs => if (!visited.contains(b)) {
f(b);
visited += b;
traverse0(bs ::: b.successors);
} else
traverse0(bs);
}
assert(startBlock.predecessors == Nil,
"Starting traverse from a block with predecessors: " + this);
traverse0(startBlock :: Nil)
}
def traverse(f: BasicBlock => Unit) = blocks.toList foreach f;
/* This method applies the given function to each basic block. */
def traverseFeedBack(f: (BasicBlock, HashMap[BasicBlock, Boolean]) => Unit) = {
val visited : HashMap[BasicBlock, Boolean] = new HashMap;
visited ++= blocks.elements.map(x => (x, false));
var blockToVisit: List[BasicBlock] = List(startBlock)
while (!blockToVisit.isEmpty) {
blockToVisit match {
case b::xs =>
if (!visited(b)) {
f(b, visited);
blockToVisit = b.successors ::: xs;
visited += (b -> true)
} else
blockToVisit = xs
case _ =>
error("impossible match")
}
}
}
/** 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 = {
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 = _
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 ((f) => f.symbol == s);
def lookupMethod(s: Symbol) = methods find ((m) => m.symbol == s);
def lookupMethod(s: Name) = methods find ((m) => m.symbol.name == s);
}
/** 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.hasFlag(Flags.STATIC) || symbol.hasFlag(Flags.STATICMEMBER) || symbol.owner.isImplClass;
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.toList) 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 (val b <- code.blocks.toList;
b.successors.length == 1;
val succ = b.successors.head;
succ ne b;
succ.predecessors.length == 1;
succ.predecessors.head eq b;
!(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.remove { b1 => b1 == succ } }
} while (nextBlock.isDefinedAt(succ))
bb.close
} else
bb = nextBlock.keys.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 toString(): String = sym.toString()
}
}