From 1b8dc120dd156e34e43132134dfa1f228cd1f497 Mon Sep 17 00:00:00 2001 From: Adriaan Moors Date: Mon, 30 Apr 2012 13:35:06 +0200 Subject: moving patmat to its own phase sort field accessors, necessary after typers -- apparently... don't throw TypeError, use issueTypeError don't run patmat phase when -Xoldpatmat only virtualize matches when -Xexperimental recycle cps type of match for re-typechecking: when one of the internal cps-type-state annotations is present, strip all CPS annotations a cps-type-state-annotated type makes no sense as an expected type (matchX.tpe is used as pt in translateMatch) don't synth FunctionN impls during typer, only do this for PartialFunction updated check now function synth for match is deferred until uncurry patmat-transform try/catch with match in cps cleanup in selective anf remove TODO: can there be cases that are not CaseDefs -- nope --- src/compiler/scala/tools/nsc/Global.scala | 8 + src/compiler/scala/tools/nsc/ast/Trees.scala | 5 + .../tools/nsc/typechecker/PatMatVirtualiser.scala | 1792 ------------------- .../tools/nsc/typechecker/PatternMatching.scala | 1839 ++++++++++++++++++++ .../tools/nsc/typechecker/SyntheticMethods.scala | 1 + .../scala/tools/nsc/typechecker/Typers.scala | 74 +- .../tools/selectivecps/CPSAnnotationChecker.scala | 85 +- .../tools/selectivecps/SelectiveANFTransform.scala | 5 +- .../tools/selectivecps/SelectiveCPSTransform.scala | 3 +- test/files/neg/gadts1.check | 5 +- test/files/neg/patmat-type-check.check | 14 +- test/files/neg/t0418.check | 5 +- test/files/neg/t112706A.check | 5 +- test/files/neg/t3392.check | 5 +- test/files/neg/t418.check | 5 +- test/files/neg/t4515.check | 4 +- test/files/neg/t5589neg.check | 5 +- test/files/run/inner-parse.check | 1 + test/files/run/programmatic-main.check | 47 +- test/files/run/virtpatmat_staging.flags | 2 +- 20 files changed, 1975 insertions(+), 1935 deletions(-) delete mode 100644 src/compiler/scala/tools/nsc/typechecker/PatMatVirtualiser.scala create mode 100644 src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala index 8c6c927640..959ce427bb 100644 --- a/src/compiler/scala/tools/nsc/Global.scala +++ b/src/compiler/scala/tools/nsc/Global.scala @@ -462,6 +462,13 @@ class Global(var currentSettings: Settings, var reporter: Reporter) extends Symb val global: Global.this.type = Global.this } with Analyzer + // phaseName = "patmat" + object patmat extends { + val global: Global.this.type = Global.this + val runsAfter = List("typer") + val runsRightAfter = Some("typer") + } with PatternMatching + // phaseName = "superaccessors" object superAccessors extends { val global: Global.this.type = Global.this @@ -682,6 +689,7 @@ class Global(var currentSettings: Settings, var reporter: Reporter) extends Symb analyzer.namerFactory -> "resolve names, attach symbols to named trees", analyzer.packageObjects -> "load package objects", analyzer.typerFactory -> "the meat and potatoes: type the trees", + patmat -> "translate match expressions", superAccessors -> "add super accessors in traits and nested classes", extensionMethods -> "add extension methods for inline classes", pickler -> "serialize symbol tables", diff --git a/src/compiler/scala/tools/nsc/ast/Trees.scala b/src/compiler/scala/tools/nsc/ast/Trees.scala index 34b37073fd..a355db4d9a 100644 --- a/src/compiler/scala/tools/nsc/ast/Trees.scala +++ b/src/compiler/scala/tools/nsc/ast/Trees.scala @@ -234,6 +234,11 @@ trait Trees extends reflect.internal.Trees { self: Global => } } + // used when a phase is disabled + object noopTransformer extends Transformer { + override def transformUnit(unit: CompilationUnit): Unit = {} + } + override protected def xtransform(transformer: super.Transformer, tree: Tree): Tree = tree match { case DocDef(comment, definition) => transformer.treeCopy.DocDef(tree, comment, transformer.transform(definition)) diff --git a/src/compiler/scala/tools/nsc/typechecker/PatMatVirtualiser.scala b/src/compiler/scala/tools/nsc/typechecker/PatMatVirtualiser.scala deleted file mode 100644 index b3f4b10865..0000000000 --- a/src/compiler/scala/tools/nsc/typechecker/PatMatVirtualiser.scala +++ /dev/null @@ -1,1792 +0,0 @@ -/* NSC -- new Scala compiler - * Copyright 2005-2011 LAMP/EPFL - * @author Adriaan Moors - */ - -package scala.tools.nsc -package typechecker - -import symtab._ -import Flags.{MUTABLE, METHOD, LABEL, SYNTHETIC} -import language.postfixOps - -/** Translate pattern matching into method calls (these methods form a zero-plus monad), similar in spirit to how for-comprehensions are compiled. - * - * For each case, express all patterns as extractor calls, guards as 0-ary extractors, and sequence them using `flatMap` - * (lifting the body of the case into the monad using `one`). - * - * Cases are combined into a pattern match using the `orElse` combinator (the implicit failure case is expressed using the monad's `zero`). - - * TODO: - * - interaction with CPS - * - Array patterns - * - implement spec more closely (see TODO's) - * - DCE - * - use TypeTags for type testing - * - * (longer-term) TODO: - * - user-defined unapplyProd - * - recover GADT typing by locally inserting implicit witnesses to type equalities derived from the current case, and considering these witnesses during subtyping (?) - * - recover exhaustivity and unreachability checking using a variation on the type-safe builder pattern - */ -trait PatMatVirtualiser extends ast.TreeDSL { self: Analyzer => - import global._ - import definitions._ - - val SYNTH_CASE = Flags.CASE | SYNTHETIC - - object TranslatedMatchAttachment - case class DefaultOverrideMatchAttachment(default: Tree) - - object vpmName { - val one = newTermName("one") - val drop = newTermName("drop") - val flatMap = newTermName("flatMap") - val get = newTermName("get") - val guard = newTermName("guard") - val isEmpty = newTermName("isEmpty") - val orElse = newTermName("orElse") - val outer = newTermName("") - val runOrElse = newTermName("runOrElse") - val zero = newTermName("zero") - val _match = newTermName("__match") // don't call the val __match, since that will trigger virtual pattern matching... - - def counted(str: String, i: Int) = newTermName(str+i) - } - - object MatchTranslator { - def apply(typer: Typer): MatchTranslation with CodegenCore = { - import typer._ - // typing `_match` to decide which MatchTranslator to create adds 4% to quick.comp.timer - val matchStrategy: Tree = ( - if (!context.isNameInScope(vpmName._match)) null // fast path, avoiding the next line if there's no __match to be seen - else newTyper(context.makeImplicit(reportAmbiguousErrors = false)).silent(_.typed(Ident(vpmName._match), EXPRmode, WildcardType), reportAmbiguousErrors = false) match { - case SilentResultValue(ms) => ms - case _ => null - } - ) - if (matchStrategy eq null) new OptimizingMatchTranslator(typer) - else new PureMatchTranslator(typer, matchStrategy) - } - } - - class PureMatchTranslator(val typer: Typer, val matchStrategy: Tree) extends MatchTranslation with TreeMakers with PureCodegen - class OptimizingMatchTranslator(val typer: Typer) extends MatchTranslation with TreeMakers with MatchOptimizations - -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// -// talking to userland -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// - - /** Interface with user-defined match monad? - * if there's a `__match` in scope, we use this as the match strategy, assuming it conforms to MatchStrategy as defined below: - - type Matcher[P[_], M[+_], A] = { - def flatMap[B](f: P[A] => M[B]): M[B] - def orElse[B >: A](alternative: => M[B]): M[B] - } - - abstract class MatchStrategy[P[_], M[+_]] { - // runs the matcher on the given input - def runOrElse[T, U](in: P[T])(matcher: P[T] => M[U]): P[U] - - def zero: M[Nothing] - def one[T](x: P[T]): M[T] - def guard[T](cond: P[Boolean], then: => P[T]): M[T] - def isSuccess[T, U](x: P[T])(f: P[T] => M[U]): P[Boolean] // used for isDefinedAt - } - - * P and M are derived from one's signature (`def one[T](x: P[T]): M[T]`) - - - * if no `__match` is found, we assume the following implementation (and generate optimized code accordingly) - - object __match extends MatchStrategy[({type Id[x] = x})#Id, Option] { - def zero = None - def one[T](x: T) = Some(x) - // NOTE: guard's return type must be of the shape M[T], where M is the monad in which the pattern match should be interpreted - def guard[T](cond: Boolean, then: => T): Option[T] = if(cond) Some(then) else None - def runOrElse[T, U](x: T)(f: T => Option[U]): U = f(x) getOrElse (throw new MatchError(x)) - def isSuccess[T, U](x: T)(f: T => Option[U]): Boolean = !f(x).isEmpty - } - - */ - trait MatchMonadInterface { - val typer: Typer - val matchOwner = typer.context.owner - - def inMatchMonad(tp: Type): Type - def pureType(tp: Type): Type - final def matchMonadResult(tp: Type): Type = - tp.baseType(matchMonadSym).typeArgs match { - case arg :: Nil => arg - case _ => ErrorType - } - - protected def matchMonadSym: Symbol - } - - trait MatchTranslation extends MatchMonadInterface { self: TreeMakers with CodegenCore => - import typer.{typed, context, silent, reallyExists} - // import typer.infer.containsUnchecked - - /** Implement a pattern match by turning its cases (including the implicit failure case) - * into the corresponding (monadic) extractors, and combining them with the `orElse` combinator. - * - * For `scrutinee match { case1 ... caseN }`, the resulting tree has the shape - * `runOrElse(scrutinee)(x => translateCase1(x).orElse(translateCase2(x)).....orElse(zero))` - * - * NOTE: the resulting tree is not type checked, nor are nested pattern matches transformed - * thus, you must typecheck the result (and that will in turn translate nested matches) - * this could probably optimized... (but note that the matchStrategy must be solved for each nested patternmatch) - */ - def translateMatch(match_ : Match): Tree = { - val Match(selector, cases) = match_ - - // we don't transform after uncurry - // (that would require more sophistication when generating trees, - // and the only place that emits Matches after typers is for exception handling anyway) - if(phase.id >= currentRun.uncurryPhase.id) debugwarn("running translateMatch at "+ phase +" on "+ selector +" match "+ cases) - // println("translating "+ cases.mkString("{", "\n", "}")) - - def repeatedToSeq(tp: Type): Type = (tp baseType RepeatedParamClass) match { - case TypeRef(_, RepeatedParamClass, arg :: Nil) => seqType(arg) - case _ => tp - } - - val selectorTp = repeatedToSeq(elimAnonymousClass(selector.tpe.widen.withoutAnnotations)) - val pt0 = match_.tpe - - // we've packed the type for each case in typedMatch so that if all cases have the same existential case, we get a clean lub - // here, we should open up the existential again - // relevant test cases: pos/existentials-harmful.scala, pos/gadt-gilles.scala, pos/t2683.scala, pos/virtpatmat_exist4.scala - // TODO: fix skolemizeExistential (it should preserve annotations, right?) - val pt = repeatedToSeq(pt0.skolemizeExistential(context.owner, context.tree) withAnnotations pt0.annotations) - - // the alternative to attaching the default case override would be to simply - // append the default to the list of cases and suppress the unreachable case error that may arise (once we detect that...) - val matchFailGenOverride = match_ firstAttachment {case DefaultOverrideMatchAttachment(default) => ((scrut: Tree) => default)} - - val selectorSym = freshSym(selector.pos, pureType(selectorTp)) setFlag SYNTH_CASE - // pt = Any* occurs when compiling test/files/pos/annotDepMethType.scala with -Xexperimental - combineCases(selector, selectorSym, cases map translateCase(selectorSym, pt), pt, matchOwner, matchFailGenOverride) - } - - // return list of typed CaseDefs that are supported by the backend (typed/bind/wildcard) - // we don't have a global scrutinee -- the caught exception must be bound in each of the casedefs - // there's no need to check the scrutinee for null -- "throw null" becomes "throw new NullPointerException" - // try to simplify to a type-based switch, or fall back to a catch-all case that runs a normal pattern match - // unlike translateMatch, we type our result before returning it - def translateTry(caseDefs: List[CaseDef], pt: Type, pos: Position): List[CaseDef] = - // if they're already simple enough to be handled by the back-end, we're done - if (caseDefs forall treeInfo.isCatchCase) caseDefs - else { - val swatches = { // switch-catches - val bindersAndCases = caseDefs map { caseDef => - // generate a fresh symbol for each case, hoping we'll end up emitting a type-switch (we don't have a global scrut there) - // if we fail to emit a fine-grained switch, have to do translateCase again with a single scrutSym (TODO: uniformize substitution on treemakers so we can avoid this) - val caseScrutSym = freshSym(pos, pureType(ThrowableClass.tpe)) - (caseScrutSym, propagateSubstitution(translateCase(caseScrutSym, pt)(caseDef), EmptySubstitution)) - } - - for(cases <- emitTypeSwitch(bindersAndCases, pt).toList; - if cases forall treeInfo.isCatchCase; // must check again, since it's not guaranteed -- TODO: can we eliminate this? e.g., a type test could test for a trait or a non-trivial prefix, which are not handled by the back-end - cse <- cases) yield fixerUpper(matchOwner, pos)(cse).asInstanceOf[CaseDef] - } - - val catches = if (swatches.nonEmpty) swatches else { - val scrutSym = freshSym(pos, pureType(ThrowableClass.tpe)) - val casesNoSubstOnly = caseDefs map { caseDef => (propagateSubstitution(translateCase(scrutSym, pt)(caseDef), EmptySubstitution))} - - val exSym = freshSym(pos, pureType(ThrowableClass.tpe), "ex") - - List( - atPos(pos) { - CaseDef( - Bind(exSym, Ident(nme.WILDCARD)), // TODO: does this need fixing upping? - EmptyTree, - combineCasesNoSubstOnly(CODE.REF(exSym), scrutSym, casesNoSubstOnly, pt, matchOwner, Some(scrut => Throw(CODE.REF(exSym)))) - ) - }) - } - - typer.typedCases(catches, ThrowableClass.tpe, WildcardType) - } - - - - /** The translation of `pat if guard => body` has two aspects: - * 1) the substitution due to the variables bound by patterns - * 2) the combination of the extractor calls using `flatMap`. - * - * 2) is easy -- it looks like: `translatePattern_1.flatMap(translatePattern_2....flatMap(translatePattern_N.flatMap(translateGuard.flatMap((x_i) => success(Xbody(x_i)))))...)` - * this must be right-leaning tree, as can be seen intuitively by considering the scope of bound variables: - * variables bound by pat_1 must be visible from the function inside the left-most flatMap right up to Xbody all the way on the right - * 1) is tricky because translatePattern_i determines the shape of translatePattern_i+1: - * zoom in on `translatePattern_1.flatMap(translatePattern_2)` for example -- it actually looks more like: - * `translatePattern_1(x_scrut).flatMap((x_1) => {y_i -> x_1._i}translatePattern_2)` - * - * `x_1` references the result (inside the monad) of the extractor corresponding to `pat_1`, - * this result holds the values for the constructor arguments, which translatePattern_1 has extracted - * from the object pointed to by `x_scrut`. The `y_i` are the symbols bound by `pat_1` (in order) - * in the scope of the remainder of the pattern, and they must thus be replaced by: - * - (for 1-ary unapply) x_1 - * - (for n-ary unapply, n > 1) selection of the i'th tuple component of `x_1` - * - (for unapplySeq) x_1.apply(i) - * - * in the treemakers, - * - * Thus, the result type of `translatePattern_i`'s extractor must conform to `M[(T_1,..., T_n)]`. - * - * Operationally, phase 1) is a foldLeft, since we must consider the depth-first-flattening of - * the transformed patterns from left to right. For every pattern ast node, it produces a transformed ast and - * a function that will take care of binding and substitution of the next ast (to the right). - * - */ - def translateCase(scrutSym: Symbol, pt: Type)(caseDef: CaseDef) = caseDef match { case CaseDef(pattern, guard, body) => - translatePattern(scrutSym, pattern) ++ translateGuard(guard) :+ translateBody(body, pt) - } - - def translatePattern(patBinder: Symbol, patTree: Tree): List[TreeMaker] = { - // a list of TreeMakers that encode `patTree`, and a list of arguments for recursive invocations of `translatePattern` to encode its subpatterns - type TranslationStep = (List[TreeMaker], List[(Symbol, Tree)]) - @inline def withSubPats(treeMakers: List[TreeMaker], subpats: (Symbol, Tree)*): TranslationStep = (treeMakers, subpats.toList) - @inline def noFurtherSubPats(treeMakers: TreeMaker*): TranslationStep = (treeMakers.toList, Nil) - - val pos = patTree.pos - - def translateExtractorPattern(extractor: ExtractorCall): TranslationStep = { - if (!extractor.isTyped) throw new TypeError(pos, "Could not typecheck extractor call: "+ extractor) - // if (extractor.resultInMonad == ErrorType) throw new TypeError(pos, "Unsupported extractor type: "+ extractor.tpe) - - // must use type `tp`, which is provided by extractor's result, not the type expected by binder, - // as b.info may be based on a Typed type ascription, which has not been taken into account yet by the translation - // (it will later result in a type test when `tp` is not a subtype of `b.info`) - // TODO: can we simplify this, together with the Bound case? - (extractor.subPatBinders, extractor.subPatTypes).zipped foreach { case (b, tp) => b setInfo tp } // println("changing "+ b +" : "+ b.info +" -> "+ tp); - - // println("translateExtractorPattern checking parameter type: "+ (patBinder, patBinder.info.widen, extractor.paramType, patBinder.info.widen <:< extractor.paramType)) - // example check: List[Int] <:< ::[Int] - // TODO: extractor.paramType may contain unbound type params (run/t2800, run/t3530) - val (typeTestTreeMaker, patBinderOrCasted) = - if (needsTypeTest(patBinder.info.widen, extractor.paramType)) { - // chain a type-testing extractor before the actual extractor call - // it tests the type, checks the outer pointer and casts to the expected type - // TODO: the outer check is mandated by the spec for case classes, but we do it for user-defined unapplies as well [SPEC] - // (the prefix of the argument passed to the unapply must equal the prefix of the type of the binder) - val treeMaker = TypeTestTreeMaker(patBinder, extractor.paramType, pos) - (List(treeMaker), treeMaker.nextBinder) - } else (Nil, patBinder) - - withSubPats(typeTestTreeMaker :+ extractor.treeMaker(patBinderOrCasted, pos), extractor.subBindersAndPatterns: _*) - } - - - object MaybeBoundTyped { - /** Decompose the pattern in `tree`, of shape C(p_1, ..., p_N), into a list of N symbols, and a list of its N sub-trees - * The list of N symbols contains symbols for every bound name as well as the un-named sub-patterns (fresh symbols are generated here for these). - * The returned type is the one inferred by inferTypedPattern (`owntype`) - * - * @arg patBinder symbol used to refer to the result of the previous pattern's extractor (will later be replaced by the outer tree with the correct tree to refer to that patterns result) - */ - def unapply(tree: Tree): Option[(Symbol, Type)] = tree match { - // the Ident subpattern can be ignored, subpatBinder or patBinder tell us all we need to know about it - case Bound(subpatBinder, typed@Typed(Ident(_), tpt)) if typed.tpe ne null => Some((subpatBinder, typed.tpe)) - case Bind(_, typed@Typed(Ident(_), tpt)) if typed.tpe ne null => Some((patBinder, typed.tpe)) - case Typed(Ident(_), tpt) if tree.tpe ne null => Some((patBinder, tree.tpe)) - case _ => None - } - } - - val (treeMakers, subpats) = patTree match { - // skip wildcard trees -- no point in checking them - case WildcardPattern() => noFurtherSubPats() - case UnApply(unfun, args) => - // TODO: check unargs == args - // println("unfun: "+ (unfun.tpe, unfun.symbol.ownerChain, unfun.symbol.info, patBinder.info)) - translateExtractorPattern(ExtractorCall(unfun, args)) - - /** A constructor pattern is of the form c(p1, ..., pn) where n ≥ 0. - It consists of a stable identifier c, followed by element patterns p1, ..., pn. - The constructor c is a simple or qualified name which denotes a case class (§5.3.2). - - If the case class is monomorphic, then it must conform to the expected type of the pattern, - and the formal parameter types of x’s primary constructor (§5.3) are taken as the expected types of the element patterns p1, ..., pn. - - If the case class is polymorphic, then its type parameters are instantiated so that the instantiation of c conforms to the expected type of the pattern. - The instantiated formal parameter types of c’s primary constructor are then taken as the expected types of the component patterns p1, ..., pn. - - The pattern matches all objects created from constructor invocations c(v1, ..., vn) where each element pattern pi matches the corresponding value vi . - A special case arises when c’s formal parameter types end in a repeated parameter. This is further discussed in (§8.1.9). - **/ - case Apply(fun, args) => - ExtractorCall.fromCaseClass(fun, args) map translateExtractorPattern getOrElse { - error("cannot find unapply member for "+ fun +" with args "+ args) - noFurtherSubPats() - } - - /** A typed pattern x : T consists of a pattern variable x and a type pattern T. - The type of x is the type pattern T, where each type variable and wildcard is replaced by a fresh, unknown type. - This pattern matches any value matched by the type pattern T (§8.2); it binds the variable name to that value. - **/ - // must treat Typed and Bind together -- we need to know the patBinder of the Bind pattern to get at the actual type - case MaybeBoundTyped(subPatBinder, pt) => - // a typed pattern never has any subtrees - noFurtherSubPats(TypeAndEqualityTestTreeMaker(subPatBinder, patBinder, pt, pos)) - - /** A pattern binder x@p consists of a pattern variable x and a pattern p. - The type of the variable x is the static type T of the pattern p. - This pattern matches any value v matched by the pattern p, - provided the run-time type of v is also an instance of T, <-- TODO! https://issues.scala-lang.org/browse/SI-1503 - and it binds the variable name to that value. - **/ - case Bound(subpatBinder, p) => - // replace subpatBinder by patBinder (as if the Bind was not there) - withSubPats(List(SubstOnlyTreeMaker(subpatBinder, patBinder)), - // must be patBinder, as subpatBinder has the wrong info: even if the bind assumes a better type, this is not guaranteed until we cast - (patBinder, p) - ) - - /** 8.1.4 Literal Patterns - A literal pattern L matches any value that is equal (in terms of ==) to the literal L. - The type of L must conform to the expected type of the pattern. - - 8.1.5 Stable Identifier Patterns (a stable identifier r (see §3.1)) - The pattern matches any value v such that r == v (§12.1). - The type of r must conform to the expected type of the pattern. - **/ - case Literal(Constant(_)) | Ident(_) | Select(_, _) => - noFurtherSubPats(EqualityTestTreeMaker(patBinder, patTree, pos)) - - case Alternative(alts) => - noFurtherSubPats(AlternativesTreeMaker(patBinder, alts map (translatePattern(patBinder, _)), alts.head.pos)) - - /* TODO: Paul says about future version: I think this should work, and always intended to implement if I can get away with it. - case class Foo(x: Int, y: String) - case class Bar(z: Int) - - def f(x: Any) = x match { case Foo(x, _) | Bar(x) => x } // x is lub of course. - */ - - case Bind(n, p) => // this happens in certain ill-formed programs, there'll be an error later - // println("WARNING: Bind tree with unbound symbol "+ patTree) - noFurtherSubPats() // there's no symbol -- something's wrong... don't fail here though (or should we?) - - // case Star(_) | ArrayValue | This => error("stone age pattern relics encountered!") - - case _ => - error("unsupported pattern: "+ patTree +"(a "+ patTree.getClass +")") - noFurtherSubPats() - } - - treeMakers ++ subpats.flatMap { case (binder, pat) => - translatePattern(binder, pat) // recurse on subpatterns - } - } - - def translateGuard(guard: Tree): List[TreeMaker] = - if (guard == EmptyTree) Nil - else List(GuardTreeMaker(guard)) - - // TODO: 1) if we want to support a generalisation of Kotlin's patmat continue, must not hard-wire lifting into the monad (which is now done by codegen.one), - // so that user can generate failure when needed -- use implicit conversion to lift into monad on-demand? - // to enable this, probably need to move away from Option to a monad specific to pattern-match, - // so that we can return Option's from a match without ambiguity whether this indicates failure in the monad, or just some result in the monad - // 2) body.tpe is the type of the body after applying the substitution that represents the solution of GADT type inference - // need the explicit cast in case our substitutions in the body change the type to something that doesn't take GADT typing into account - def translateBody(body: Tree, matchPt: Type): TreeMaker = - BodyTreeMaker(body, matchPt) - - -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// -// helper methods: they analyze types and trees in isolation, but they are not (directly) concerned with the structure of the overall translation -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// - - object ExtractorCall { - def apply(unfun: Tree, args: List[Tree]): ExtractorCall = new ExtractorCallRegular(unfun, args) - - def fromCaseClass(fun: Tree, args: List[Tree]): Option[ExtractorCall] = Some(new ExtractorCallProd(fun, args)) - - // THE PRINCIPLED SLOW PATH -- NOT USED - // generate a call to the (synthetically generated) extractor of a case class - // NOTE: it's an apply, not a select, since in general an extractor call may have multiple argument lists (including an implicit one) - // that we need to preserve, so we supply the scrutinee as Ident(nme.SELECTOR_DUMMY), - // and replace that dummy by a reference to the actual binder in translateExtractorPattern - def fromCaseClassUnapply(fun: Tree, args: List[Tree]): Option[ExtractorCall] = { - // TODO: can we rework the typer so we don't have to do all this twice? - // undo rewrite performed in (5) of adapt - val orig = fun match {case tpt: TypeTree => tpt.original case _ => fun} - val origSym = orig.symbol - val extractor = unapplyMember(origSym.filter(sym => reallyExists(unapplyMember(sym.tpe))).tpe) - - if((fun.tpe eq null) || fun.tpe.isError || (extractor eq NoSymbol)) { - None - } else { - // this is a tricky balance: pos/t602.scala, pos/sudoku.scala, run/virtpatmat_alts.scala must all be happy - // bypass typing at own risk: val extractorCall = Select(orig, extractor) setType caseClassApplyToUnapplyTp(fun.tpe) - // can't always infer type arguments (pos/t602): - /* case class Span[K <: Ordered[K]](low: Option[K]) { - override def equals(x: Any): Boolean = x match { - case Span((low0 @ _)) if low0 equals low => true - } - }*/ - // so... leave undetermined type params floating around if we have to - // (if we don't infer types, uninstantiated type params show up later: pos/sudoku.scala) - // (see also run/virtpatmat_alts.scala) - val savedUndets = context.undetparams - val extractorCall = try { - context.undetparams = Nil - silent(_.typed(Apply(Select(orig, extractor), List(Ident(nme.SELECTOR_DUMMY) setType fun.tpe.finalResultType)), EXPRmode, WildcardType), reportAmbiguousErrors = false) match { - case SilentResultValue(extractorCall) => extractorCall // if !extractorCall.containsError() - case _ => - // this fails to resolve overloading properly... - // Apply(typedOperator(Select(orig, extractor)), List(Ident(nme.SELECTOR_DUMMY))) // no need to set the type of the dummy arg, it will be replaced anyway - - // println("funtpe after = "+ fun.tpe.finalResultType) - // println("orig: "+(orig, orig.tpe)) - val tgt = typed(orig, EXPRmode | QUALmode | POLYmode, HasMember(extractor.name)) // can't specify fun.tpe.finalResultType as the type for the extractor's arg, - // as it may have been inferred incorrectly (see t602, where it's com.mosol.sl.Span[Any], instead of com.mosol.sl.Span[?K]) - // println("tgt = "+ (tgt, tgt.tpe)) - val oper = typed(Select(tgt, extractor.name), EXPRmode | FUNmode | POLYmode | TAPPmode, WildcardType) - // println("oper: "+ (oper, oper.tpe)) - Apply(oper, List(Ident(nme.SELECTOR_DUMMY))) // no need to set the type of the dummy arg, it will be replaced anyway - } - } finally context.undetparams = savedUndets - - Some(this(extractorCall, args)) // TODO: simplify spliceApply? - } - } - } - - abstract class ExtractorCall(val args: List[Tree]) { - val nbSubPats = args.length - - // everything okay, captain? - def isTyped : Boolean - - def isSeq: Boolean - lazy val lastIsStar = (nbSubPats > 0) && treeInfo.isStar(args.last) - - // to which type should the previous binder be casted? - def paramType : Type - - // binder has been casted to paramType if necessary - def treeMaker(binder: Symbol, pos: Position): TreeMaker - - // `subPatBinders` are the variables bound by this pattern in the following patterns - // subPatBinders are replaced by references to the relevant part of the extractor's result (tuple component, seq element, the result as-is) - lazy val subPatBinders = args map { - case Bound(b, p) => b - case p => freshSym(p.pos, prefix = "p") - } - - lazy val subBindersAndPatterns: List[(Symbol, Tree)] = (subPatBinders zip args) map { - case (b, Bound(_, p)) => (b, p) - case bp => bp - } - - def subPatTypes: List[Type] = - if(isSeq) { - val TypeRef(pre, SeqClass, args) = seqTp - // do repeated-parameter expansion to match up with the expected number of arguments (in casu, subpatterns) - formalTypes(rawSubPatTypes.init :+ typeRef(pre, RepeatedParamClass, args), nbSubPats) - } else rawSubPatTypes - - protected def rawSubPatTypes: List[Type] - - protected def seqTp = rawSubPatTypes.last baseType SeqClass - protected def seqLenCmp = rawSubPatTypes.last member nme.lengthCompare - protected lazy val firstIndexingBinder = rawSubPatTypes.length - 1 // rawSubPatTypes.last is the Seq, thus there are `rawSubPatTypes.length - 1` non-seq elements in the tuple - protected lazy val lastIndexingBinder = if(lastIsStar) nbSubPats-2 else nbSubPats-1 - protected lazy val expectedLength = lastIndexingBinder - firstIndexingBinder + 1 - protected lazy val minLenToCheck = if(lastIsStar) 1 else 0 - protected def seqTree(binder: Symbol) = tupleSel(binder)(firstIndexingBinder+1) - protected def tupleSel(binder: Symbol)(i: Int): Tree = codegen.tupleSel(binder)(i) - - // the trees that select the subpatterns on the extractor's result, referenced by `binder` - // require isSeq - protected def subPatRefsSeq(binder: Symbol): List[Tree] = { - val indexingIndices = (0 to (lastIndexingBinder-firstIndexingBinder)) - val nbIndexingIndices = indexingIndices.length - - // this error-condition has already been checked by checkStarPatOK: - // if(isSeq) assert(firstIndexingBinder + nbIndexingIndices + (if(lastIsStar) 1 else 0) == nbSubPats, "(resultInMonad, ts, subPatTypes, subPats)= "+(resultInMonad, ts, subPatTypes, subPats)) - // there are `firstIndexingBinder` non-seq tuple elements preceding the Seq - (((1 to firstIndexingBinder) map tupleSel(binder)) ++ - // then we have to index the binder that represents the sequence for the remaining subpatterns, except for... - (indexingIndices map codegen.index(seqTree(binder))) ++ - // the last one -- if the last subpattern is a sequence wildcard: drop the prefix (indexed by the refs on the line above), return the remainder - (if(!lastIsStar) Nil else List( - if(nbIndexingIndices == 0) seqTree(binder) - else codegen.drop(seqTree(binder))(nbIndexingIndices)))).toList - } - - // the trees that select the subpatterns on the extractor's result, referenced by `binder` - // require (nbSubPats > 0 && (!lastIsStar || isSeq)) - protected def subPatRefs(binder: Symbol): List[Tree] = - if (nbSubPats == 0) Nil - else if (isSeq) subPatRefsSeq(binder) - else ((1 to nbSubPats) map tupleSel(binder)).toList - - protected def lengthGuard(binder: Symbol): Option[Tree] = - // no need to check unless it's an unapplySeq and the minimal length is non-trivially satisfied - if (!isSeq || (expectedLength < minLenToCheck)) None - else { import CODE._ - // `binder.lengthCompare(expectedLength)` - def checkExpectedLength = (seqTree(binder) DOT seqLenCmp)(LIT(expectedLength)) - - // the comparison to perform - // when the last subpattern is a wildcard-star the expectedLength is but a lower bound - // (otherwise equality is required) - def compareOp: (Tree, Tree) => Tree = - if (lastIsStar) _ INT_>= _ - else _ INT_== _ - - // `if (binder != null && $checkExpectedLength [== | >=] 0) then else zero` - Some((seqTree(binder) ANY_!= NULL) AND compareOp(checkExpectedLength, ZERO)) - } - } - - // TODO: to be called when there's a def unapplyProd(x: T): U - // U must have N members _1,..., _N -- the _i are type checked, call their type Ti, - // - // for now only used for case classes -- pretending there's an unapplyProd that's the identity (and don't call it) - class ExtractorCallProd(fun: Tree, args: List[Tree]) extends ExtractorCall(args) { - // TODO: fix the illegal type bound in pos/t602 -- type inference messes up before we get here: - /*override def equals(x$1: Any): Boolean = ... - val o5: Option[com.mosol.sl.Span[Any]] = // Span[Any] --> Any is not a legal type argument for Span! - */ - // private val orig = fun match {case tpt: TypeTree => tpt.original case _ => fun} - // private val origExtractorTp = unapplyMember(orig.symbol.filter(sym => reallyExists(unapplyMember(sym.tpe))).tpe).tpe - // private val extractorTp = if (wellKinded(fun.tpe)) fun.tpe else existentialAbstraction(origExtractorTp.typeParams, origExtractorTp.resultType) - // println("ExtractorCallProd: "+ (fun.tpe, existentialAbstraction(origExtractorTp.typeParams, origExtractorTp.resultType))) - // println("ExtractorCallProd: "+ (fun.tpe, args map (_.tpe))) - private def constructorTp = fun.tpe - - def isTyped = fun.isTyped - - // to which type should the previous binder be casted? - def paramType = constructorTp.finalResultType - - def isSeq: Boolean = rawSubPatTypes.nonEmpty && isRepeatedParamType(rawSubPatTypes.last) - protected def rawSubPatTypes = constructorTp.paramTypes - - // binder has type paramType - def treeMaker(binder: Symbol, pos: Position): TreeMaker = { - // checks binder ne null before chaining to the next extractor - ProductExtractorTreeMaker(binder, lengthGuard(binder), Substitution(subPatBinders, subPatRefs(binder))) - } - -/* TODO: remove special case when the following bug is fixed -class Foo(x: Other) { x._1 } // BUG: can't refer to _1 if its defining class has not been type checked yet -case class Other(y: String) --- this is ok: -case class Other(y: String) -class Foo(x: Other) { x._1 } // no error in this order -*/ - override protected def tupleSel(binder: Symbol)(i: Int): Tree = { import CODE._ - // reference the (i-1)th case accessor if it exists, otherwise the (i-1)th tuple component - val caseAccs = binder.info.typeSymbol.caseFieldAccessors - if (caseAccs isDefinedAt (i-1)) REF(binder) DOT caseAccs(i-1) - else codegen.tupleSel(binder)(i) - } - - override def toString(): String = "case class "+ (if (constructorTp eq null) fun else paramType.typeSymbol) +" with arguments "+ args - } - - class ExtractorCallRegular(extractorCallIncludingDummy: Tree, args: List[Tree]) extends ExtractorCall(args) { - private lazy val Some(Apply(extractorCall, _)) = extractorCallIncludingDummy.find{ case Apply(_, List(Ident(nme.SELECTOR_DUMMY))) => true case _ => false } - - def tpe = extractorCall.tpe - def isTyped = (tpe ne NoType) && extractorCall.isTyped && (resultInMonad ne ErrorType) - def paramType = tpe.paramTypes.head - def resultType = tpe.finalResultType - def isSeq = extractorCall.symbol.name == nme.unapplySeq - - def treeMaker(patBinderOrCasted: Symbol, pos: Position): TreeMaker = { - // the extractor call (applied to the binder bound by the flatMap corresponding to the previous (i.e., enclosing/outer) pattern) - val extractorApply = atPos(pos)(spliceApply(patBinderOrCasted)) - val binder = freshSym(pos, pureType(resultInMonad)) // can't simplify this when subPatBinders.isEmpty, since UnitClass.tpe is definitely wrong when isSeq, and resultInMonad should always be correct since it comes directly from the extractor's result type - ExtractorTreeMaker(extractorApply, lengthGuard(binder), binder, Substitution(subPatBinders, subPatRefs(binder)))(resultType.typeSymbol == BooleanClass) - } - - override protected def seqTree(binder: Symbol): Tree = - if (firstIndexingBinder == 0) CODE.REF(binder) - else super.seqTree(binder) - - // the trees that select the subpatterns on the extractor's result, referenced by `binder` - // require (nbSubPats > 0 && (!lastIsStar || isSeq)) - override protected def subPatRefs(binder: Symbol): List[Tree] = - if (!isSeq && nbSubPats == 1) List(CODE.REF(binder)) // special case for extractors - else super.subPatRefs(binder) - - protected def spliceApply(binder: Symbol): Tree = { - object splice extends Transformer { - override def transform(t: Tree) = t match { - case Apply(x, List(Ident(nme.SELECTOR_DUMMY))) => - treeCopy.Apply(t, x, List(CODE.REF(binder))) - case _ => super.transform(t) - } - } - splice.transform(extractorCallIncludingDummy) - } - - // what's the extractor's result type in the monad? - // turn an extractor's result type into something `monadTypeToSubPatTypesAndRefs` understands - protected lazy val resultInMonad: Type = if(!hasLength(tpe.paramTypes, 1)) ErrorType else { - if (resultType.typeSymbol == BooleanClass) UnitClass.tpe - else matchMonadResult(resultType) - } - - protected lazy val rawSubPatTypes = - if (resultInMonad.typeSymbol eq UnitClass) Nil - else if(nbSubPats == 1) List(resultInMonad) - else getProductArgs(resultInMonad) match { - case Nil => List(resultInMonad) - case x => x - } - - override def toString() = extractorCall +": "+ extractorCall.tpe +" (symbol= "+ extractorCall.symbol +")." - } - - /** A conservative approximation of which patterns do not discern anything. - * They are discarded during the translation. - */ - object WildcardPattern { - def unapply(pat: Tree): Boolean = pat match { - case Bind(nme.WILDCARD, WildcardPattern()) => true // don't skip when binding an interesting symbol! - case Ident(nme.WILDCARD) => true - case Star(WildcardPattern()) => true - case x: Ident => treeInfo.isVarPattern(x) - case Alternative(ps) => ps forall (WildcardPattern.unapply(_)) - case EmptyTree => true - case _ => false - } - } - - object Bound { - def unapply(t: Tree): Option[(Symbol, Tree)] = t match { - case t@Bind(n, p) if (t.symbol ne null) && (t.symbol ne NoSymbol) => // pos/t2429 does not satisfy these conditions - Some((t.symbol, p)) - case _ => None - } - } - } - -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// -// substitution -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// - trait TypedSubstitution extends MatchMonadInterface { - object Substitution { - def apply(from: Symbol, to: Tree) = new Substitution(List(from), List(to)) - // requires sameLength(from, to) - def apply(from: List[Symbol], to: List[Tree]) = - if (from nonEmpty) new Substitution(from, to) else EmptySubstitution - } - - class Substitution(val from: List[Symbol], val to: List[Tree]) { - // We must explicitly type the trees that we replace inside some other tree, since the latter may already have been typed, - // and will thus not be retyped. This means we might end up with untyped subtrees inside bigger, typed trees. - def apply(tree: Tree): Tree = { - // according to -Ystatistics 10% of translateMatch's time is spent in this method... - // since about half of the typedSubst's end up being no-ops, the check below shaves off 5% of the time spent in typedSubst - if (!tree.exists { case i@Ident(_) => from contains i.symbol case _ => false}) tree - else (new Transformer { - @inline private def typedIfOrigTyped(to: Tree, origTp: Type): Tree = - if (origTp == null || origTp == NoType) to - // important: only type when actually substing and when original tree was typed - // (don't need to use origTp as the expected type, though, and can't always do this anyway due to unknown type params stemming from polymorphic extractors) - else typer.typed(to, EXPRmode, WildcardType) - - override def transform(tree: Tree): Tree = { - def subst(from: List[Symbol], to: List[Tree]): Tree = - if (from.isEmpty) tree - else if (tree.symbol == from.head) typedIfOrigTyped(to.head.shallowDuplicate, tree.tpe) - else subst(from.tail, to.tail) - - tree match { - case Ident(_) => subst(from, to) - case _ => super.transform(tree) - } - } - }).transform(tree) - } - - - // the substitution that chains `other` before `this` substitution - // forall t: Tree. this(other(t)) == (this >> other)(t) - def >>(other: Substitution): Substitution = { - val (fromFiltered, toFiltered) = (from, to).zipped filter { (f, t) => !other.from.contains(f) } - new Substitution(other.from ++ fromFiltered, other.to.map(apply) ++ toFiltered) // a quick benchmarking run indicates the `.map(apply)` is not too costly - } - override def toString = (from zip to) mkString("Substitution(", ", ", ")") - } - - object EmptySubstitution extends Substitution(Nil, Nil) { - override def apply(tree: Tree): Tree = tree - override def >>(other: Substitution): Substitution = other - } - } - -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// -// the making of the trees -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// - trait TreeMakers extends TypedSubstitution { self: CodegenCore => - def optimizeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type): (List[List[TreeMaker]], List[Tree]) = - (cases, Nil) - - def emitSwitch(scrut: Tree, scrutSym: Symbol, cases: List[List[TreeMaker]], pt: Type, matchFailGenOverride: Option[Tree => Tree]): Option[Tree] = - None - - // for catch (no need to customize match failure) - def emitTypeSwitch(bindersAndCases: List[(Symbol, List[TreeMaker])], pt: Type): Option[List[CaseDef]] = - None - - abstract class TreeMaker { - /** captures the scope and the value of the bindings in patterns - * important *when* the substitution happens (can't accumulate and do at once after the full matcher has been constructed) - */ - def substitution: Substitution = - if (currSub eq null) localSubstitution - else currSub - - protected def localSubstitution: Substitution - - private[TreeMakers] def incorporateOuterSubstitution(outerSubst: Substitution): Unit = { - if (currSub ne null) { - println("BUG: incorporateOuterSubstitution called more than once for "+ (this, currSub, outerSubst)) - Thread.dumpStack() - } - else currSub = outerSubst >> substitution - } - private[this] var currSub: Substitution = null - - // build Tree that chains `next` after the current extractor - def chainBefore(next: Tree)(casegen: Casegen): Tree - } - - trait NoNewBinders extends TreeMaker { - protected val localSubstitution: Substitution = EmptySubstitution - } - - case class TrivialTreeMaker(tree: Tree) extends TreeMaker with NoNewBinders { - def chainBefore(next: Tree)(casegen: Casegen): Tree = tree - } - - case class BodyTreeMaker(body: Tree, matchPt: Type) extends TreeMaker with NoNewBinders { - def chainBefore(next: Tree)(casegen: Casegen): Tree = // assert(next eq EmptyTree) - atPos(body.pos)(casegen.one(substitution(body))) // since SubstOnly treemakers are dropped, need to do it here - } - - case class SubstOnlyTreeMaker(prevBinder: Symbol, nextBinder: Symbol) extends TreeMaker { - val localSubstitution = Substitution(prevBinder, CODE.REF(nextBinder)) - def chainBefore(next: Tree)(casegen: Casegen): Tree = substitution(next) - } - - abstract class FunTreeMaker extends TreeMaker { - val nextBinder: Symbol - } - - abstract class CondTreeMaker extends FunTreeMaker { - val pos: Position - val prevBinder: Symbol - val nextBinderTp: Type - val cond: Tree - val res: Tree - - lazy val nextBinder = freshSym(pos, nextBinderTp) - lazy val localSubstitution = Substitution(List(prevBinder), List(CODE.REF(nextBinder))) - - def chainBefore(next: Tree)(casegen: Casegen): Tree = - atPos(pos)(casegen.flatMapCond(cond, res, nextBinder, substitution(next))) - } - - /** - * Make a TreeMaker that will result in an extractor call specified by `extractor` - * the next TreeMaker (here, we don't know which it'll be) is chained after this one by flatMap'ing - * a function with binder `nextBinder` over our extractor's result - * the function's body is determined by the next TreeMaker - * in this function's body, and all the subsequent ones, references to the symbols in `from` will be replaced by the corresponding tree in `to` - */ - case class ExtractorTreeMaker(extractor: Tree, extraCond: Option[Tree], nextBinder: Symbol, localSubstitution: Substitution)(extractorReturnsBoolean: Boolean) extends FunTreeMaker { - def chainBefore(next: Tree)(casegen: Casegen): Tree = { - val condAndNext = extraCond map (casegen.ifThenElseZero(_, next)) getOrElse next - atPos(extractor.pos)( - if (extractorReturnsBoolean) casegen.flatMapCond(extractor, CODE.UNIT, nextBinder, substitution(condAndNext)) - else casegen.flatMap(extractor, nextBinder, substitution(condAndNext)) - ) - } - - override def toString = "X"+(extractor, nextBinder) - } - - // TODO: allow user-defined unapplyProduct - case class ProductExtractorTreeMaker(prevBinder: Symbol, extraCond: Option[Tree], localSubstitution: Substitution) extends TreeMaker { import CODE._ - def chainBefore(next: Tree)(casegen: Casegen): Tree = { - val nullCheck = REF(prevBinder) OBJ_NE NULL - val cond = extraCond map (nullCheck AND _) getOrElse nullCheck - casegen.ifThenElseZero(cond, substitution(next)) - } - - override def toString = "P"+(prevBinder, extraCond getOrElse "", localSubstitution) - } - - // tack an outer test onto `cond` if binder.info and expectedType warrant it - def maybeWithOuterCheck(binder: Symbol, expectedTp: Type)(cond: Tree): Tree = { import CODE._ - if ( !((expectedTp.prefix eq NoPrefix) || expectedTp.prefix.typeSymbol.isPackageClass) - && needsOuterTest(expectedTp, binder.info, matchOwner)) { - val expectedPrefix = expectedTp.prefix match { - case ThisType(clazz) => THIS(clazz) - case pre => REF(pre.prefix, pre.termSymbol) - } - - // ExplicitOuter replaces `Select(q, outerSym) OBJ_EQ expectedPrefix` by `Select(q, outerAccessor(outerSym.owner)) OBJ_EQ expectedPrefix` - // if there's an outer accessor, otherwise the condition becomes `true` -- TODO: can we improve needsOuterTest so there's always an outerAccessor? - val outer = expectedTp.typeSymbol.newMethod(vpmName.outer) setInfo expectedTp.prefix setFlag SYNTHETIC - val outerCheck = (Select(codegen._asInstanceOf(binder, expectedTp), outer)) OBJ_EQ expectedPrefix - - // first check cond, since that should ensure we're not selecting outer on null - codegen.and(cond, outerCheck) - } - else - cond - } - - // containsUnchecked: also need to test when erasing pt loses crucial information (maybe we can recover it using a TypeTag) - def needsTypeTest(tp: Type, pt: Type): Boolean = !(tp <:< pt) // || containsUnchecked(pt) - // TODO: try to find the TypeTag for the binder's type and the expected type, and if they exists, - // check that the TypeTag of the binder's type conforms to the TypeTag of the expected type - private def typeTest(binderToTest: Symbol, expectedTp: Type, disableOuterCheck: Boolean = false, dynamic: Boolean = false): Tree = { import CODE._ - // def coreTest = - if (disableOuterCheck) codegen._isInstanceOf(binderToTest, expectedTp) else maybeWithOuterCheck(binderToTest, expectedTp)(codegen._isInstanceOf(binderToTest, expectedTp)) - // [Eugene to Adriaan] use `resolveErasureTag` instead of `findManifest`. please, provide a meaningful position - // if (opt.experimental && containsUnchecked(expectedTp)) { - // if (dynamic) { - // val expectedTpTagTree = findManifest(expectedTp, true) - // if (!expectedTpTagTree.isEmpty) - // ((expectedTpTagTree DOT "erasure".toTermName) DOT "isAssignableFrom".toTermName)(REF(binderToTest) DOT nme.getClass_) - // else - // coreTest - // } else { - // val expectedTpTagTree = findManifest(expectedTp, true) - // val binderTpTagTree = findManifest(binderToTest.info, true) - // if(!(expectedTpTagTree.isEmpty || binderTpTagTree.isEmpty)) - // coreTest AND (binderTpTagTree DOT nme.CONFORMS)(expectedTpTagTree) - // else - // coreTest - // } - // } else coreTest - } - - // need to substitute since binder may be used outside of the next extractor call (say, in the body of the case) - case class TypeTestTreeMaker(prevBinder: Symbol, nextBinderTp: Type, pos: Position) extends CondTreeMaker { - val cond = typeTest(prevBinder, nextBinderTp, dynamic = true) - val res = codegen._asInstanceOf(prevBinder, nextBinderTp) - override def toString = "TT"+(prevBinder, nextBinderTp) - } - - // implements the run-time aspects of (§8.2) (typedPattern has already done the necessary type transformations) - // TODO: normalize construction, which yields a combination of a EqualityTestTreeMaker (when necessary) and a TypeTestTreeMaker - case class TypeAndEqualityTestTreeMaker(prevBinder: Symbol, patBinder: Symbol, pt: Type, pos: Position) extends CondTreeMaker { - val nextBinderTp = glb(List(patBinder.info.widen, pt)) - - /** Type patterns consist of types, type variables, and wildcards. A type pattern T is of one of the following forms: - - A reference to a class C, p.C, or T#C. - This type pattern matches any non-null instance of the given class. - Note that the prefix of the class, if it is given, is relevant for determining class instances. - For instance, the pattern p.C matches only instances of classes C which were created with the path p as prefix. - The bottom types scala.Nothing and scala.Null cannot be used as type patterns, because they would match nothing in any case. - - - A singleton type p.type. - This type pattern matches only the value denoted by the path p - (that is, a pattern match involved a comparison of the matched value with p using method eq in class AnyRef). // TODO: the actual pattern matcher uses ==, so that's what I'm using for now - // https://issues.scala-lang.org/browse/SI-4577 "pattern matcher, still disappointing us at equality time" - - - A compound type pattern T1 with ... with Tn where each Ti is a type pat- tern. - This type pattern matches all values that are matched by each of the type patterns Ti. - - - A parameterized type pattern T[a1,...,an], where the ai are type variable patterns or wildcards _. - This type pattern matches all values which match T for some arbitrary instantiation of the type variables and wildcards. - The bounds or alias type of these type variable are determined as described in (§8.3). - - - A parameterized type pattern scala.Array[T1], where T1 is a type pattern. // TODO - This type pattern matches any non-null instance of type scala.Array[U1], where U1 is a type matched by T1. - **/ - - // generate the tree for the run-time test that follows from the fact that - // a `scrut` of known type `scrutTp` is expected to have type `expectedTp` - // uses maybeWithOuterCheck to check the type's prefix - private def typeAndEqualityTest(patBinder: Symbol, pt: Type): Tree = { import CODE._ - // TODO: `null match { x : T }` will yield a check that (indirectly) tests whether `null ne null` - // don't bother (so that we don't end up with the warning "comparing values of types Null and Null using `ne' will always yield false") - def genEqualsAndInstanceOf(sym: Symbol): Tree - = codegen._equals(REF(sym), patBinder) AND typeTest(patBinder, pt.widen, disableOuterCheck = true) - - def isRefTp(tp: Type) = tp <:< AnyRefClass.tpe - - val patBinderTp = patBinder.info.widen - def isMatchUnlessNull = isRefTp(pt) && !needsTypeTest(patBinderTp, pt) - - // TODO: [SPEC] type test for Array - // TODO: use TypeTags to improve tests (for erased types we can do better when we have a TypeTag) - pt match { - case SingleType(_, sym) /*this implies sym.isStable*/ => genEqualsAndInstanceOf(sym) // TODO: [SPEC] the spec requires `eq` instead of `==` here - case ThisType(sym) if sym.isModule => genEqualsAndInstanceOf(sym) // must use == to support e.g. List() == Nil - case ThisType(sym) => REF(patBinder) OBJ_EQ This(sym) - case ConstantType(Constant(null)) if isRefTp(patBinderTp) => REF(patBinder) OBJ_EQ NULL - case ConstantType(const) => codegen._equals(Literal(const), patBinder) - case _ if isMatchUnlessNull => maybeWithOuterCheck(patBinder, pt)(REF(patBinder) OBJ_NE NULL) - case _ => typeTest(patBinder, pt) - } - } - - val cond = typeAndEqualityTest(patBinder, pt) - val res = codegen._asInstanceOf(patBinder, nextBinderTp) - - // TODO: remove this - def isStraightTypeTest = cond match { case TypeApply(_, _) => cond.symbol == Any_isInstanceOf case _ => false } - - override def toString = "TET"+(patBinder, pt) - } - - // need to substitute to deal with existential types -- TODO: deal with existentials better, don't substitute (see RichClass during quick.comp) - case class EqualityTestTreeMaker(prevBinder: Symbol, patTree: Tree, pos: Position) extends CondTreeMaker { - val nextBinderTp = prevBinder.info.widen - - // NOTE: generate `patTree == patBinder`, since the extractor must be in control of the equals method (also, patBinder may be null) - // equals need not be well-behaved, so don't intersect with pattern's (stabilized) type (unlike MaybeBoundTyped's accumType, where it's required) - val cond = codegen._equals(patTree, prevBinder) - val res = CODE.REF(prevBinder) - override def toString = "ET"+(prevBinder, patTree) - } - - case class AlternativesTreeMaker(prevBinder: Symbol, var altss: List[List[TreeMaker]], pos: Position) extends TreeMaker with NoNewBinders { - // don't substitute prevBinder to nextBinder, a set of alternatives does not need to introduce a new binder, simply reuse the previous one - - override private[TreeMakers] def incorporateOuterSubstitution(outerSubst: Substitution): Unit = { - super.incorporateOuterSubstitution(outerSubst) - altss = altss map (alts => propagateSubstitution(alts, substitution)) - } - - def chainBefore(next: Tree)(codegenAlt: Casegen): Tree = { import CODE._ - atPos(pos){ - // one alternative may still generate multiple trees (e.g., an extractor call + equality test) - // (for now,) alternatives may not bind variables (except wildcards), so we don't care about the final substitution built internally by makeTreeMakers - val combinedAlts = altss map (altTreeMakers => - ((casegen: Casegen) => combineExtractors(altTreeMakers :+ TrivialTreeMaker(casegen.one(TRUE_typed)))(casegen)) - ) - - val findAltMatcher = codegenAlt.matcher(EmptyTree, NoSymbol, BooleanClass.tpe)(combinedAlts, Some(x => FALSE_typed)) - codegenAlt.ifThenElseZero(findAltMatcher, substitution(next)) - } - } - } - - case class GuardTreeMaker(guardTree: Tree) extends TreeMaker with NoNewBinders { - def chainBefore(next: Tree)(casegen: Casegen): Tree = casegen.flatMapGuard(substitution(guardTree), next) - override def toString = "G("+ guardTree +")" - } - - // combineExtractors changes the current substitution's of the tree makers in `treeMakers` - // requires propagateSubstitution(treeMakers) has been called - def combineExtractors(treeMakers: List[TreeMaker])(casegen: Casegen): Tree = - treeMakers.foldRight(EmptyTree: Tree)((a, b) => a.chainBefore(b)(casegen)) - - - def removeSubstOnly(makers: List[TreeMaker]) = makers filterNot (_.isInstanceOf[SubstOnlyTreeMaker]) - - // a foldLeft to accumulate the localSubstitution left-to-right - // it drops SubstOnly tree makers, since their only goal in life is to propagate substitutions to the next tree maker, which is fullfilled by propagateSubstitution - def propagateSubstitution(treeMakers: List[TreeMaker], initial: Substitution): List[TreeMaker] = { - var accumSubst: Substitution = initial - treeMakers foreach { maker => - maker incorporateOuterSubstitution accumSubst - accumSubst = maker.substitution - } - removeSubstOnly(treeMakers) - } - - // calls propagateSubstitution on the treemakers - def combineCases(scrut: Tree, scrutSym: Symbol, casesRaw: List[List[TreeMaker]], pt: Type, owner: Symbol, matchFailGenOverride: Option[Tree => Tree]): Tree = { - // drops SubstOnlyTreeMakers, since their effect is now contained in the TreeMakers that follow them - val casesNoSubstOnly = casesRaw map (propagateSubstitution(_, EmptySubstitution)) - combineCasesNoSubstOnly(scrut, scrutSym, casesNoSubstOnly, pt, owner, matchFailGenOverride) - } - - def combineCasesNoSubstOnly(scrut: Tree, scrutSym: Symbol, casesNoSubstOnly: List[List[TreeMaker]], pt: Type, owner: Symbol, matchFailGenOverride: Option[Tree => Tree]): Tree = - fixerUpper(owner, scrut.pos){ - val ptDefined = if (isFullyDefined(pt)) pt else NoType - def matchFailGen = (matchFailGenOverride orElse Some(CODE.MATCHERROR(_: Tree))) - // println("combining cases: "+ (casesNoSubstOnly.map(_.mkString(" >> ")).mkString("{", "\n", "}"))) - - emitSwitch(scrut, scrutSym, casesNoSubstOnly, pt, matchFailGenOverride).getOrElse{ - if (casesNoSubstOnly nonEmpty) { - // before optimizing, check casesNoSubstOnly for presence of a default case, - // since DCE will eliminate trivial cases like `case _ =>`, even if they're the last one - // exhaustivity and reachability must be checked before optimization as well - // TODO: improve notion of trivial/irrefutable -- a trivial type test before the body still makes for a default case - // ("trivial" depends on whether we're emitting a straight match or an exception, or more generally, any supertype of scrutSym.tpe is a no-op) - // irrefutability checking should use the approximation framework also used for CSE, unreachability and exhaustivity checking - val synthCatchAll = - if (casesNoSubstOnly.nonEmpty && { - val nonTrivLast = casesNoSubstOnly.last - nonTrivLast.nonEmpty && nonTrivLast.head.isInstanceOf[BodyTreeMaker] - }) None - else matchFailGen - - val (cases, toHoist) = optimizeCases(scrutSym, casesNoSubstOnly, pt) - - val matchRes = codegen.matcher(scrut, scrutSym, pt)(cases map combineExtractors, synthCatchAll) - - if (toHoist isEmpty) matchRes else Block(toHoist, matchRes) - } else { - codegen.matcher(scrut, scrutSym, pt)(Nil, matchFailGen) - } - } - } - - // TODO: do this during tree construction, but that will require tracking the current owner in treemakers - // TODO: assign more fine-grained positions - // fixes symbol nesting, assigns positions - protected def fixerUpper(origOwner: Symbol, pos: Position) = new Traverser { - currentOwner = origOwner - - override def traverse(t: Tree) { - if (t != EmptyTree && t.pos == NoPosition) { - t.setPos(pos) - } - t match { - case Function(_, _) if t.symbol == NoSymbol => - t.symbol = currentOwner.newAnonymousFunctionValue(t.pos) - // println("new symbol for "+ (t, t.symbol.ownerChain)) - case Function(_, _) if (t.symbol.owner == NoSymbol) || (t.symbol.owner == origOwner) => - // println("fundef: "+ (t, t.symbol.ownerChain, currentOwner.ownerChain)) - t.symbol.owner = currentOwner - case d : DefTree if (d.symbol != NoSymbol) && ((d.symbol.owner == NoSymbol) || (d.symbol.owner == origOwner)) => // don't indiscriminately change existing owners! (see e.g., pos/t3440, pos/t3534, pos/unapplyContexts2) - // println("def: "+ (d, d.symbol.ownerChain, currentOwner.ownerChain)) - if(d.symbol.isLazy) { // for lazy val's accessor -- is there no tree?? - assert(d.symbol.lazyAccessor != NoSymbol && d.symbol.lazyAccessor.owner == d.symbol.owner, d.symbol.lazyAccessor) - d.symbol.lazyAccessor.owner = currentOwner - } - if(d.symbol.moduleClass ne NoSymbol) - d.symbol.moduleClass.owner = currentOwner - - d.symbol.owner = currentOwner - // case _ if (t.symbol != NoSymbol) && (t.symbol ne null) => - // println("untouched "+ (t, t.getClass, t.symbol.ownerChain, currentOwner.ownerChain)) - case _ => - } - super.traverse(t) - } - - // override def apply - // println("before fixerupper: "+ xTree) - // currentRun.trackerFactory.snapshot() - // println("after fixerupper") - // currentRun.trackerFactory.snapshot() - } - } - - -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// -// generate actual trees -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// - trait CodegenCore extends MatchMonadInterface { - private var ctr = 0 - def freshName(prefix: String) = {ctr += 1; vpmName.counted(prefix, ctr)} - - // assert(owner ne null); assert(owner ne NoSymbol) - def freshSym(pos: Position, tp: Type = NoType, prefix: String = "x") = - NoSymbol.newTermSymbol(freshName(prefix), pos) setInfo tp - - // codegen relevant to the structure of the translation (how extractors are combined) - trait AbsCodegen { - def matcher(scrut: Tree, scrutSym: Symbol, restpe: Type)(cases: List[Casegen => Tree], matchFailGen: Option[Tree => Tree]): Tree - - // local / context-free - def _asInstanceOf(b: Symbol, tp: Type): Tree - def _equals(checker: Tree, binder: Symbol): Tree - def _isInstanceOf(b: Symbol, tp: Type): Tree - def and(a: Tree, b: Tree): Tree - def drop(tgt: Tree)(n: Int): Tree - def index(tgt: Tree)(i: Int): Tree - def mkZero(tp: Type): Tree - def tupleSel(binder: Symbol)(i: Int): Tree - } - - // structure - trait Casegen extends AbsCodegen { import CODE._ - def one(res: Tree): Tree - - def flatMap(prev: Tree, b: Symbol, next: Tree): Tree - def flatMapCond(cond: Tree, res: Tree, nextBinder: Symbol, next: Tree): Tree - def flatMapGuard(cond: Tree, next: Tree): Tree - def ifThenElseZero(c: Tree, then: Tree): Tree = IF (c) THEN then ELSE zero - protected def zero: Tree - } - - def codegen: AbsCodegen - - def typesConform(tp: Type, pt: Type) = ((tp eq pt) || (tp <:< pt)) - - abstract class CommonCodegen extends AbsCodegen { import CODE._ - def fun(arg: Symbol, body: Tree): Tree = Function(List(ValDef(arg)), body) - def genTypeApply(tfun: Tree, args: Type*): Tree = if(args contains NoType) tfun else TypeApply(tfun, args.toList map TypeTree) - def tupleSel(binder: Symbol)(i: Int): Tree = (REF(binder) DOT nme.productAccessorName(i)) // make tree that accesses the i'th component of the tuple referenced by binder - def index(tgt: Tree)(i: Int): Tree = tgt APPLY (LIT(i)) - def drop(tgt: Tree)(n: Int): Tree = (tgt DOT vpmName.drop) (LIT(n)) - def _equals(checker: Tree, binder: Symbol): Tree = checker MEMBER_== REF(binder) // NOTE: checker must be the target of the ==, that's the patmat semantics for ya - def and(a: Tree, b: Tree): Tree = a AND b - - // drop annotations generated by CPS plugin etc, since its annotationchecker rejects T @cps[U] <: Any - // let's assume for now annotations don't affect casts, drop them there, and bring them back using the outer Typed tree - private def mkCast(t: Tree, tp: Type) = - Typed(gen.mkAsInstanceOf(t, tp.withoutAnnotations, true, false), TypeTree() setType tp) - - // the force is needed mainly to deal with the GADT typing hack (we can't detect it otherwise as tp nor pt need contain an abstract type, we're just casting wildly) - def _asInstanceOf(t: Tree, tp: Type, force: Boolean = false): Tree = if (!force && (t.tpe ne NoType) && t.isTyped && typesConform(t.tpe, tp)) t else mkCast(t, tp) - def _asInstanceOf(b: Symbol, tp: Type): Tree = if (typesConform(b.info, tp)) REF(b) else mkCast(REF(b), tp) - def _isInstanceOf(b: Symbol, tp: Type): Tree = gen.mkIsInstanceOf(REF(b), tp.withoutAnnotations, true, false) - // if (typesConform(b.info, tpX)) { println("warning: emitted spurious isInstanceOf: "+(b, tp)); TRUE } - - // duplicated out of frustration with cast generation - def mkZero(tp: Type): Tree = { - tp.typeSymbol match { - case UnitClass => Literal(Constant()) - case BooleanClass => Literal(Constant(false)) - case FloatClass => Literal(Constant(0.0f)) - case DoubleClass => Literal(Constant(0.0d)) - case ByteClass => Literal(Constant(0.toByte)) - case ShortClass => Literal(Constant(0.toShort)) - case IntClass => Literal(Constant(0)) - case LongClass => Literal(Constant(0L)) - case CharClass => Literal(Constant(0.toChar)) - case _ => gen.mkAsInstanceOf(Literal(Constant(null)), tp, any = true, wrapInApply = false) // the magic incantation is true/false here - } - } - } - } - - trait PureMatchMonadInterface extends MatchMonadInterface { - val matchStrategy: Tree - - def inMatchMonad(tp: Type): Type = appliedType(oneSig, List(tp)).finalResultType - def pureType(tp: Type): Type = appliedType(oneSig, List(tp)).paramTypes.headOption getOrElse NoType // fail gracefully (otherwise we get crashes) - protected def matchMonadSym = oneSig.finalResultType.typeSymbol - - import CODE._ - def _match(n: Name): SelectStart = matchStrategy DOT n - - private lazy val oneSig: Type = - typer.typed(_match(vpmName.one), EXPRmode | POLYmode | TAPPmode | FUNmode, WildcardType).tpe // TODO: error message - } - - trait PureCodegen extends CodegenCore with PureMatchMonadInterface { - def codegen: AbsCodegen = pureCodegen - - object pureCodegen extends CommonCodegen with Casegen { import CODE._ - //// methods in MatchingStrategy (the monad companion) -- used directly in translation - // __match.runOrElse(`scrut`)(`scrutSym` => `matcher`) - // TODO: consider catchAll, or virtualized matching will break in exception handlers - def matcher(scrut: Tree, scrutSym: Symbol, restpe: Type)(cases: List[Casegen => Tree], matchFailGen: Option[Tree => Tree]): Tree = - _match(vpmName.runOrElse) APPLY (scrut) APPLY (fun(scrutSym, cases map (f => f(this)) reduceLeft typedOrElse)) - - // __match.one(`res`) - def one(res: Tree): Tree = (_match(vpmName.one)) (res) - // __match.zero - protected def zero: Tree = _match(vpmName.zero) - // __match.guard(`c`, `then`) - def guard(c: Tree, then: Tree): Tree = _match(vpmName.guard) APPLY (c, then) - - //// methods in the monad instance -- used directly in translation - // `prev`.flatMap(`b` => `next`) - def flatMap(prev: Tree, b: Symbol, next: Tree): Tree = (prev DOT vpmName.flatMap)(fun(b, next)) - // `thisCase`.orElse(`elseCase`) - def typedOrElse(thisCase: Tree, elseCase: Tree): Tree = (thisCase DOT vpmName.orElse) APPLY (elseCase) - // __match.guard(`cond`, `res`).flatMap(`nextBinder` => `next`) - def flatMapCond(cond: Tree, res: Tree, nextBinder: Symbol, next: Tree): Tree = flatMap(guard(cond, res), nextBinder, next) - // __match.guard(`guardTree`, ()).flatMap((_: P[Unit]) => `next`) - def flatMapGuard(guardTree: Tree, next: Tree): Tree = flatMapCond(guardTree, CODE.UNIT, freshSym(guardTree.pos, pureType(UnitClass.tpe)), next) - } - } - - -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// -// OPTIMIZATIONS -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// - -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// -// decisions, decisions -/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// - - trait TreeMakerApproximation extends TreeMakers { self: CodegenCore => - object Test { - var currId = 0 - } - case class Test(cond: Cond, treeMaker: TreeMaker) { - // def <:<(other: Test) = cond <:< other.cond - // def andThen_: (prev: List[Test]): List[Test] = - // prev.filterNot(this <:< _) :+ this - - private val reusedBy = new collection.mutable.HashSet[Test] - var reuses: Option[Test] = None - def registerReuseBy(later: Test): Unit = { - assert(later.reuses.isEmpty, later.reuses) - reusedBy += later - later.reuses = Some(this) - } - - val id = { Test.currId += 1; Test.currId} - override def toString = - if (cond eq Top) "T" - else if(cond eq Havoc) "!?" - else "T"+ id + (if(reusedBy nonEmpty) "!["+ treeMaker +"]" else (if(reuses.isEmpty) "["+ treeMaker +"]" else " cf. T"+reuses.get.id)) - } - - object Cond { - // def refines(self: Cond, other: Cond): Boolean = (self, other) match { - // case (Bottom, _) => true - // case (Havoc , _) => true - // case (_ , Top) => true - // case (_ , _) => false - // } - var currId = 0 - } - - abstract class Cond { - // def testedPath: Tree - // def <:<(other: Cond) = Cond.refines(this, other) - - val id = { Cond.currId += 1; Cond.currId} - } - - // does not contribute any knowledge - case object Top extends Cond - - // takes away knowledge. e.g., a user-defined guard - case object Havoc extends Cond - - // we know everything! everything! - // this either means the case is unreachable, - // or that it is statically known to be picked -- at this point in the decision tree --> no point in emitting further alternatives - // case object Bottom extends Cond - - - object EqualityCond { - private val uniques = new collection.mutable.HashMap[(Tree, Tree), EqualityCond] - def apply(testedPath: Tree, rhs: Tree): EqualityCond = uniques getOrElseUpdate((testedPath, rhs), new EqualityCond(testedPath, rhs)) - } - class EqualityCond(testedPath: Tree, rhs: Tree) extends Cond { - // def negation = TopCond // inequality doesn't teach us anything - // do simplification when we know enough about the tree statically: - // - collapse equal trees - // - accumulate tests when (in)equality not known statically - // - become bottom when we statically know this can never match - - override def toString = testedPath +" == "+ rhs +"#"+ id - } - - object TypeCond { - private val uniques = new collection.mutable.HashMap[(Tree, Type), TypeCond] - def apply(testedPath: Tree, pt: Type): TypeCond = uniques getOrElseUpdate((testedPath, pt), new TypeCond(testedPath, pt)) - } - class TypeCond(testedPath: Tree, pt: Type) extends Cond { - // def negation = TopCond // inequality doesn't teach us anything - // do simplification when we know enough about the tree statically: - // - collapse equal trees - // - accumulate tests when (in)equality not known statically - // - become bottom when we statically know this can never match - override def toString = testedPath +" <: "+ pt +"#"+ id - } - - object TypeAndEqualityCond { - private val uniques = new collection.mutable.HashMap[(Tree, Type), TypeAndEqualityCond] - def apply(testedPath: Tree, pt: Type): TypeAndEqualityCond = uniques getOrElseUpdate((testedPath, pt), new TypeAndEqualityCond(testedPath, pt)) - } - class TypeAndEqualityCond(testedPath: Tree, pt: Type) extends Cond { - // def negation = TopCond // inequality doesn't teach us anything - // do simplification when we know enough about the tree statically: - // - collapse equal trees - // - accumulate tests when (in)equality not known statically - // - become bottom when we statically know this can never match - override def toString = testedPath +" (<: && ==) "+ pt +"#"+ id - } - - def approximateMatch(root: Symbol, cases: List[List[TreeMaker]]): List[List[Test]] = { - // a variable in this set should never be replaced by a tree that "does not consist of a selection on a variable in this set" (intuitively) - val pointsToBound = collection.mutable.HashSet(root) - - // the substitution that renames variables to variables in pointsToBound - var normalize: Substitution = EmptySubstitution - - // replaces a variable (in pointsToBound) by a selection on another variable in pointsToBound - // TODO check: - // pointsToBound -- accumSubst.from == Set(root) && (accumSubst.from.toSet -- pointsToBound) isEmpty - var accumSubst: Substitution = EmptySubstitution - - val trees = new collection.mutable.HashSet[Tree] - - def approximateTreeMaker(tm: TreeMaker): Test = { - val subst = tm.substitution - - // find part of substitution that replaces bound symbols by new symbols, and reverse that part - // so that we don't introduce new aliases for existing symbols, thus keeping the set of bound symbols minimal - val (boundSubst, unboundSubst) = (subst.from zip subst.to) partition {case (f, t) => - t.isInstanceOf[Ident] && (t.symbol ne NoSymbol) && pointsToBound(f) - } - val (boundFrom, boundTo) = boundSubst.unzip - normalize >>= Substitution(boundTo map (_.symbol), boundFrom map (CODE.REF(_))) - // println("normalize: "+ normalize) - - val (unboundFrom, unboundTo) = unboundSubst unzip - val okSubst = Substitution(unboundFrom, unboundTo map (normalize(_))) // it's important substitution does not duplicate trees here -- it helps to keep hash consing simple, anyway - pointsToBound ++= ((okSubst.from, okSubst.to).zipped filter { (f, t) => pointsToBound exists (sym => t.exists(_.symbol == sym)) })._1 - // println("pointsToBound: "+ pointsToBound) - - accumSubst >>= okSubst - // println("accumSubst: "+ accumSubst) - - // TODO: improve, e.g., for constants - def sameValue(a: Tree, b: Tree): Boolean = (a eq b) || ((a, b) match { - case (_ : Ident, _ : Ident) => a.symbol eq b.symbol - case _ => false - }) - - // hashconsing trees (modulo value-equality) - def unique(t: Tree): Tree = - trees find (a => a.equalsStructure0(t)(sameValue)) match { - case Some(orig) => orig // println("unique: "+ (t eq orig, orig)); - case _ => trees += t; t - } - - def uniqueTp(tp: Type): Type = tp match { - // typerefs etc are already hashconsed - case _ : UniqueType => tp - case tp@RefinedType(parents, EmptyScope) => tp.memo(tp: Type)(identity) // TODO: does this help? - case _ => tp - } - - def binderToUniqueTree(b: Symbol) = unique(accumSubst(normalize(CODE.REF(b)))) - - Test(tm match { - case ProductExtractorTreeMaker(pb, None, subst) => Top // TODO: NotNullTest(prevBinder) - case tm@TypeTestTreeMaker(prevBinder, nextBinderTp, _) => TypeCond(binderToUniqueTree(prevBinder), uniqueTp(nextBinderTp)) - case tm@TypeAndEqualityTestTreeMaker(_, patBinder, pt, _) => TypeAndEqualityCond(binderToUniqueTree(patBinder), uniqueTp(pt)) - case tm@EqualityTestTreeMaker(prevBinder, patTree, _) => EqualityCond(binderToUniqueTree(prevBinder), unique(patTree)) - case ExtractorTreeMaker(_, _, _, _) - | GuardTreeMaker(_) - | ProductExtractorTreeMaker(_, Some(_), _) => Havoc - case AlternativesTreeMaker(_, _, _) => Havoc // TODO: can do better here - case SubstOnlyTreeMaker(_, _) => Top - case BodyTreeMaker(_, _) => Havoc - }, tm) - } - - cases.map { _ map approximateTreeMaker } - } - } - -//// - trait CommonSubconditionElimination extends TreeMakerApproximation { self: OptimizedCodegen => - /** a flow-sensitive, generalised, common sub-expression elimination - * reuse knowledge from performed tests - * the only sub-expressions we consider are the conditions and results of the three tests (type, type&equality, equality) - * when a sub-expression is share, it is stored in a mutable variable - * the variable is floated up so that its scope includes all of the program that shares it - * we generalize sharing to implication, where b reuses a if a => b and priors(a) => priors(b) (the priors of a sub expression form the path through the decision tree) - * - * intended to be generalised to exhaustivity/reachability checking - */ - def doCSE(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type): List[List[TreeMaker]] = { - val testss = approximateMatch(prevBinder, cases) - - // interpret: - val dependencies = new collection.mutable.LinkedHashMap[Test, Set[Cond]] - val tested = new collection.mutable.HashSet[Cond] - testss foreach { tests => - tested.clear() - tests dropWhile { test => - val cond = test.cond - if ((cond eq Havoc) || (cond eq Top)) (cond eq Top) // stop when we encounter a havoc, skip top - else { - tested += cond - - // is there an earlier test that checks our condition and whose dependencies are implied by ours? - dependencies find { case (priorTest, deps) => - ((priorTest.cond eq cond) || (deps contains cond)) && (deps subsetOf tested) - } foreach { case (priorTest, deps) => - // if so, note the dependency in both tests - priorTest registerReuseBy test - } - - dependencies(test) = tested.toSet // copies - true - } - } - } - - // find longest prefix of tests that reuse a prior test, and whose dependent conditions monotonically increase - // then, collapse these contiguous sequences of reusing tests - // store the result of the final test and the intermediate results in hoisted mutable variables (TODO: optimize: don't store intermediate results that aren't used) - // replace each reference to a variable originally bound by a collapsed test by a reference to the hoisted variable - val reused = new collection.mutable.HashMap[TreeMaker, ReusedCondTreeMaker] - var okToCall = false - val reusedOrOrig = (tm: TreeMaker) => {assert(okToCall); reused.getOrElse(tm, tm)} - - val res = testss map { tests => - var currDeps = Set[Cond]() - val (sharedPrefix, suffix) = tests span { test => - (test.cond eq Top) || (for( - reusedTest <- test.reuses; - nextDeps <- dependencies.get(reusedTest); - diff <- (nextDeps -- currDeps).headOption; - _ <- Some(currDeps = nextDeps)) - yield diff).nonEmpty - } - - val collapsedTreeMakers = if (sharedPrefix.nonEmpty) { // even sharing prefixes of length 1 brings some benefit (overhead-percentage for compiler: 26->24%, lib: 19->16%) - for (test <- sharedPrefix; reusedTest <- test.reuses) reusedTest.treeMaker match { - case reusedCTM: CondTreeMaker => reused(reusedCTM) = ReusedCondTreeMaker(reusedCTM) - case _ => - } - - // println("sharedPrefix: "+ sharedPrefix) - for (lastShared <- sharedPrefix.reverse.dropWhile(_.cond eq Top).headOption; - lastReused <- lastShared.reuses) - yield ReusingCondTreeMaker(sharedPrefix, reusedOrOrig) :: suffix.map(_.treeMaker) - } else None - - collapsedTreeMakers getOrElse tests.map(_.treeMaker) // sharedPrefix need not be empty (but it only contains Top-tests, which are dropped above) - } - okToCall = true // TODO: remove (debugging) - - res mapConserve (_ mapConserve reusedOrOrig) - } - - object ReusedCondTreeMaker { - def apply(orig: CondTreeMaker) = new ReusedCondTreeMaker(orig.prevBinder, orig.nextBinder, orig.cond, orig.res, orig.pos) - } - class ReusedCondTreeMaker(prevBinder: Symbol, val nextBinder: Symbol, cond: Tree, res: Tree, pos: Position) extends TreeMaker { import CODE._ - lazy val localSubstitution = Substitution(List(prevBinder), List(CODE.REF(nextBinder))) - lazy val storedCond = freshSym(pos, BooleanClass.tpe, "rc") setFlag MUTABLE - lazy val treesToHoist: List[Tree] = { - nextBinder setFlag MUTABLE - List(storedCond, nextBinder) map { b => VAL(b) === codegen.mkZero(b.info) } - } - - // TODO: finer-grained duplication - def chainBefore(next: Tree)(casegen: Casegen): Tree = // assert(codegen eq optimizedCodegen) - atPos(pos)(casegen.asInstanceOf[optimizedCodegen.OptimizedCasegen].flatMapCondStored(cond, storedCond, res, nextBinder, substitution(next).duplicate)) - } - - case class ReusingCondTreeMaker(sharedPrefix: List[Test], toReused: TreeMaker => TreeMaker) extends TreeMaker { import CODE._ - lazy val dropped_priors = sharedPrefix map (t => (toReused(t.treeMaker), t.reuses map (test => toReused(test.treeMaker)))) - lazy val localSubstitution = { - val (from, to) = dropped_priors.collect { - case (dropped: CondTreeMaker, Some(prior: ReusedCondTreeMaker)) => - (dropped.nextBinder, REF(prior.nextBinder)) - }.unzip - val oldSubs = dropped_priors.collect { - case (dropped: TreeMaker, _) => - dropped.substitution - } - oldSubs.foldLeft(Substitution(from, to))(_ >> _) - } - - def chainBefore(next: Tree)(casegen: Casegen): Tree = { - val cond = REF(dropped_priors.reverse.collectFirst{case (_, Some(ctm: ReusedCondTreeMaker)) => ctm}.get.storedCond) - - // TODO: finer-grained duplication -- MUST duplicate though, or we'll get VerifyErrors since sharing trees confuses lambdalift, and its confusion it emits illegal casts (diagnosed by Grzegorz: checkcast T ; invokevirtual S.m, where T not a subtype of S) - casegen.ifThenElseZero(cond, substitution(next).duplicate) - } - } - } - - - //// DCE - trait DeadCodeElimination extends TreeMakers { self: CodegenCore => - // TODO: non-trivial dead-code elimination - // e.g., the following match should compile to a simple instanceof: - // case class Ident(name: String) - // for (Ident(name) <- ts) println(name) - def doDCE(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type): List[List[TreeMaker]] = { - // do minimal DCE - cases - } - } - - //// SWITCHES -- TODO: operate on Tests rather than TreeMakers - trait SwitchEmission extends TreeMakers with OptimizedMatchMonadInterface { self: CodegenCore => - abstract class SwitchMaker { - abstract class SwitchableTreeMakerExtractor { def unapply(x: TreeMaker): Option[Tree] } - val SwitchableTreeMaker: SwitchableTreeMakerExtractor - - def alternativesSupported: Boolean - - def isDefault(x: CaseDef): Boolean - def defaultSym: Symbol - def defaultBody: Tree - def defaultCase(scrutSym: Symbol = defaultSym, body: Tree = defaultBody): CaseDef - - private def sequence[T](xs: List[Option[T]]): Option[List[T]] = - if (xs exists (_.isEmpty)) None else Some(xs.flatten) - - // empty list ==> failure - def apply(cases: List[(Symbol, List[TreeMaker])], pt: Type): List[CaseDef] = { - val caseDefs = cases map { case (scrutSym, makers) => - makers match { - // default case - case (btm@BodyTreeMaker(body, _)) :: Nil => - Some(defaultCase(scrutSym, btm.substitution(body))) - // constant (or typetest for typeSwitch) - case SwitchableTreeMaker(pattern) :: (btm@BodyTreeMaker(body, _)) :: Nil => - Some(CaseDef(pattern, EmptyTree, btm.substitution(body))) - // alternatives - case AlternativesTreeMaker(_, altss, _) :: (btm@BodyTreeMaker(body, _)) :: Nil if alternativesSupported => - val casePatterns = altss map { - case SwitchableTreeMaker(pattern) :: Nil => - Some(pattern) - case _ => - None - } - - sequence(casePatterns) map { patterns => - val substedBody = btm.substitution(body) - CaseDef(Alternative(patterns), EmptyTree, substedBody) - } - case _ => //println("can't emit switch for "+ makers) - None //failure (can't translate pattern to a switch) - } - } - - (for( - caseDefs <- sequence(caseDefs)) yield - if (caseDefs exists isDefault) caseDefs - else { - caseDefs :+ defaultCase() - } - ) getOrElse Nil - } - } - - class RegularSwitchMaker(scrutSym: Symbol, matchFailGenOverride: Option[Tree => Tree]) extends SwitchMaker { - val switchableTpe = Set(ByteClass.tpe, ShortClass.tpe, IntClass.tpe, CharClass.tpe) - val alternativesSupported = true - - object SwitchablePattern { def unapply(pat: Tree): Option[Tree] = pat match { - case Literal(const@Constant((_: Byte ) | (_: Short) | (_: Int ) | (_: Char ))) => - Some(Literal(Constant(const.intValue))) // TODO: Java 7 allows strings in switches - case _ => None - }} - - object SwitchableTreeMaker extends SwitchableTreeMakerExtractor { - def unapply(x: TreeMaker): Option[Tree] = x match { - case EqualityTestTreeMaker(_, SwitchablePattern(const), _) => Some(const) - case _ => None - } - } - - def isDefault(x: CaseDef): Boolean = x match { - case CaseDef(Ident(nme.WILDCARD), EmptyTree, _) => true - case _ => false - } - - def defaultSym: Symbol = scrutSym - def defaultBody: Tree = { import CODE._; matchFailGenOverride map (gen => gen(REF(scrutSym))) getOrElse MATCHERROR(REF(scrutSym)) } - def defaultCase(scrutSym: Symbol = defaultSym, body: Tree = defaultBody): CaseDef = { import CODE._; atPos(body.pos) { - DEFAULT ==> body - }} - } - - override def emitSwitch(scrut: Tree, scrutSym: Symbol, cases: List[List[TreeMaker]], pt: Type, matchFailGenOverride: Option[Tree => Tree]): Option[Tree] = { import CODE._ - val regularSwitchMaker = new RegularSwitchMaker(scrutSym, matchFailGenOverride) - // TODO: if patterns allow switch but the type of the scrutinee doesn't, cast (type-test) the scrutinee to the corresponding switchable type and switch on the result - if (regularSwitchMaker.switchableTpe(scrutSym.tpe)) { - val caseDefsWithDefault = regularSwitchMaker(cases map {c => (scrutSym, c)}, pt) - if (caseDefsWithDefault.length <= 2) None // not worth emitting a switch... also, the optimizer has trouble digesting tiny switches, apparently, so let's be nice and not generate them - else { - // match on scrutSym -- converted to an int if necessary -- not on scrut directly (to avoid duplicating scrut) - val scrutToInt: Tree = - if (scrutSym.tpe =:= IntClass.tpe) REF(scrutSym) - else (REF(scrutSym) DOT (nme.toInt)) - Some(BLOCK( - VAL(scrutSym) === scrut, - Match(scrutToInt, caseDefsWithDefault) withAttachment TranslatedMatchAttachment // add switch annotation - )) - } - } else None - } - - // for the catch-cases in a try/catch - private object typeSwitchMaker extends SwitchMaker { - def switchableTpe(tp: Type) = true - val alternativesSupported = false // TODO: needs either back-end support of flattening of alternatives during typers - - // TODO: there are more treemaker-sequences that can be handled by type tests - // analyze the result of approximateTreeMaker rather than the TreeMaker itself - object SwitchableTreeMaker extends SwitchableTreeMakerExtractor { - def unapply(x: TreeMaker): Option[Tree] = x match { - case tm@TypeTestTreeMaker(_, _, _) => - Some(Bind(tm.nextBinder, Typed(Ident(nme.WILDCARD), TypeTree(tm.nextBinderTp)) /* not used by back-end */)) // -- TODO: use this if binder does not occur in the body - case tm@TypeAndEqualityTestTreeMaker(_, patBinder, pt, _) if tm.isStraightTypeTest => - Some(Bind(tm.nextBinder, Typed(Ident(nme.WILDCARD), TypeTree(tm.nextBinderTp)) /* not used by back-end */)) - case _ => - None - } - } - - def isDefault(x: CaseDef): Boolean = x match { - case CaseDef(Typed(Ident(nme.WILDCARD), tpt), EmptyTree, _) if (tpt.tpe =:= ThrowableClass.tpe) => true - case CaseDef(Bind(_, Typed(Ident(nme.WILDCARD), tpt)), EmptyTree, _) if (tpt.tpe =:= ThrowableClass.tpe) => true - case CaseDef(Ident(nme.WILDCARD), EmptyTree, _) => true - case _ => false - } - - lazy val defaultSym: Symbol = freshSym(NoPosition, ThrowableClass.tpe) - def defaultBody: Tree = Throw(CODE.REF(defaultSym)) - def defaultCase(scrutSym: Symbol = defaultSym, body: Tree = defaultBody): CaseDef = { import CODE._; atPos(body.pos) { - CASE (Bind(scrutSym, Typed(Ident(nme.WILDCARD), TypeTree(ThrowableClass.tpe)))) ==> body - }} - } - - // TODO: drop null checks - override def emitTypeSwitch(bindersAndCases: List[(Symbol, List[TreeMaker])], pt: Type): Option[List[CaseDef]] = { - val caseDefsWithDefault = typeSwitchMaker(bindersAndCases, pt) - if (caseDefsWithDefault isEmpty) None - else Some(caseDefsWithDefault) - } - } - - trait OptimizedMatchMonadInterface extends MatchMonadInterface { - override def inMatchMonad(tp: Type): Type = optionType(tp) - override def pureType(tp: Type): Type = tp - override protected def matchMonadSym = OptionClass - } - - trait OptimizedCodegen extends CodegenCore with TypedSubstitution with OptimizedMatchMonadInterface { - override def codegen: AbsCodegen = optimizedCodegen - - // trait AbsOptimizedCodegen extends AbsCodegen { - // def flatMapCondStored(cond: Tree, condSym: Symbol, res: Tree, nextBinder: Symbol, next: Tree): Tree - // } - // def optimizedCodegen: AbsOptimizedCodegen - - // when we know we're targetting Option, do some inlining the optimizer won't do - // for example, `o.flatMap(f)` becomes `if(o == None) None else f(o.get)`, similarly for orElse and guard - // this is a special instance of the advanced inlining optimization that takes a method call on - // an object of a type that only has two concrete subclasses, and inlines both bodies, guarded by an if to distinguish the two cases - object optimizedCodegen extends CommonCodegen { import CODE._ - - /** Inline runOrElse and get rid of Option allocations - * - * runOrElse(scrut: scrutTp)(matcher): resTp = matcher(scrut) getOrElse ${catchAll(`scrut`)} - * the matcher's optional result is encoded as a flag, keepGoing, where keepGoing == true encodes result.isEmpty, - * if keepGoing is false, the result Some(x) of the naive translation is encoded as matchRes == x - */ - def matcher(scrut: Tree, scrutSym: Symbol, restpe: Type)(cases: List[Casegen => Tree], matchFailGen: Option[Tree => Tree]): Tree = { - val matchEnd = NoSymbol.newLabel(freshName("matchEnd"), NoPosition) setFlag SYNTH_CASE - val matchRes = NoSymbol.newValueParameter(newTermName("x"), NoPosition, SYNTHETIC) setInfo restpe.withoutAnnotations // - matchEnd setInfo MethodType(List(matchRes), restpe) - - def newCaseSym = NoSymbol.newLabel(freshName("case"), NoPosition) setInfo MethodType(Nil, restpe) setFlag SYNTH_CASE - var nextCase = newCaseSym - def caseDef(mkCase: Casegen => Tree): Tree = { - val currCase = nextCase - nextCase = newCaseSym - val casegen = new OptimizedCasegen(matchEnd, nextCase, restpe) - LabelDef(currCase, Nil, mkCase(casegen)) - } - - def catchAll = matchFailGen map { matchFailGen => - val scrutRef = if(scrutSym ne NoSymbol) REF(scrutSym) else EmptyTree // for alternatives - // must jump to matchEnd, use result generated by matchFailGen (could be `FALSE` for isDefinedAt) - LabelDef(nextCase, Nil, matchEnd APPLY (matchFailGen(scrutRef))) - // don't cast the arg to matchEnd when using PartialFun synth in uncurry, since it won't detect the throw (see gen.withDefaultCase) - // the cast is necessary when using typedMatchAnonFun-style PartialFun synth: - // (_asInstanceOf(matchFailGen(scrutRef), restpe)) - } toList - // catchAll.isEmpty iff no synthetic default case needed (the (last) user-defined case is a default) - // if the last user-defined case is a default, it will never jump to the next case; it will go immediately to matchEnd - - // the generated block is taken apart in TailCalls under the following assumptions - // the assumption is once we encounter a case, the remainder of the block will consist of cases - // the prologue may be empty, usually it is the valdef that stores the scrut - // val (prologue, cases) = stats span (s => !s.isInstanceOf[LabelDef]) - - // scrutSym == NoSymbol when generating an alternatives matcher - val scrutDef = if(scrutSym ne NoSymbol) List(VAL(scrutSym) === scrut) else Nil // for alternatives - Block( - scrutDef ++ (cases map caseDef) ++ catchAll, - LabelDef(matchEnd, List(matchRes), REF(matchRes)) - ) - } - - class OptimizedCasegen(matchEnd: Symbol, nextCase: Symbol, restpe: Type) extends CommonCodegen with Casegen { - def matcher(scrut: Tree, scrutSym: Symbol, restpe: Type)(cases: List[Casegen => Tree], matchFailGen: Option[Tree => Tree]): Tree = - optimizedCodegen.matcher(scrut, scrutSym, restpe)(cases, matchFailGen) - - // only used to wrap the RHS of a body - // res: T - // returns MatchMonad[T] - def one(res: Tree): Tree = matchEnd APPLY (_asInstanceOf(res, restpe)) // need cast for GADT magic - protected def zero: Tree = nextCase APPLY () - - // prev: MatchMonad[T] - // b: T - // next: MatchMonad[U] - // returns MatchMonad[U] - def flatMap(prev: Tree, b: Symbol, next: Tree): Tree = { - val tp = inMatchMonad(b.tpe) - val prevSym = freshSym(prev.pos, tp, "o") - val isEmpty = tp member vpmName.isEmpty - val get = tp member vpmName.get - - BLOCK( - VAL(prevSym) === prev, - // must be isEmpty and get as we don't control the target of the call (prev is an extractor call) - ifThenElseZero(NOT(prevSym DOT isEmpty), Substitution(b, prevSym DOT get)(next)) - ) - } - - // cond: Boolean - // res: T - // nextBinder: T - // next == MatchMonad[U] - // returns MatchMonad[U] - def flatMapCond(cond: Tree, res: Tree, nextBinder: Symbol, next: Tree): Tree = - ifThenElseZero(cond, BLOCK( - VAL(nextBinder) === res, - next - )) - - // guardTree: Boolean - // next: MatchMonad[T] - // returns MatchMonad[T] - def flatMapGuard(guardTree: Tree, next: Tree): Tree = - ifThenElseZero(guardTree, next) - - def flatMapCondStored(cond: Tree, condSym: Symbol, res: Tree, nextBinder: Symbol, next: Tree): Tree = - ifThenElseZero(cond, BLOCK( - condSym === TRUE_typed, - nextBinder === res, - next - )) - } - - } - } - - - trait MatchOptimizations extends CommonSubconditionElimination - with DeadCodeElimination - with SwitchEmission - with OptimizedCodegen { self: TreeMakers => - override def optimizeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type): (List[List[TreeMaker]], List[Tree]) = { - val optCases = doCSE(prevBinder, doDCE(prevBinder, cases, pt), pt) - val toHoist = ( - for (treeMakers <- optCases) - yield treeMakers.collect{case tm: ReusedCondTreeMaker => tm.treesToHoist} - ).flatten.flatten.toList - (optCases, toHoist) - } - } -} diff --git a/src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala b/src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala new file mode 100644 index 0000000000..702f279596 --- /dev/null +++ b/src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala @@ -0,0 +1,1839 @@ +/* NSC -- new Scala compiler + * + * Copyright 2012 LAMP/EPFL + * @author Adriaan Moors + */ + +package scala.tools.nsc +package typechecker + +import symtab._ +import Flags.{MUTABLE, METHOD, LABEL, SYNTHETIC} +import language.postfixOps +import scala.tools.nsc.transform.TypingTransformers +import scala.tools.nsc.transform.Transform + +/** Translate pattern matching. + * + * Either into optimized if/then/else's, + * or virtualized as method calls (these methods form a zero-plus monad), similar in spirit to how for-comprehensions are compiled. + * + * For each case, express all patterns as extractor calls, guards as 0-ary extractors, and sequence them using `flatMap` + * (lifting the body of the case into the monad using `one`). + * + * Cases are combined into a pattern match using the `orElse` combinator (the implicit failure case is expressed using the monad's `zero`). + * + * TODO: + * - exhaustivity + * - DCE (unreachability/refutability/optimization) + * - use TypeTags for type testing + * - Array patterns + * - implement spec more closely (see TODO's) + * + * (longer-term) TODO: + * - user-defined unapplyProd + * - recover GADT typing by locally inserting implicit witnesses to type equalities derived from the current case, and considering these witnesses during subtyping (?) + * - recover exhaustivity and unreachability checking using a variation on the type-safe builder pattern + */ +trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL { // self: Analyzer => + val global: Global // need to repeat here because otherwise last mixin defines global as + // SymbolTable. If we had DOT this would not be an issue + import global._ // the global environment + import definitions._ // standard classes and methods + import CODE._ + + val phaseName: String = "patmat" + + def newTransformer(unit: CompilationUnit): Transformer = + if (opt.virtPatmat) new MatchTransformer(unit) + else noopTransformer + + // duplicated from CPSUtils (avoid dependency from compiler -> cps plugin...) + private lazy val MarkerCPSAdaptPlus = definitions.getClassIfDefined("scala.util.continuations.cpsPlus") + private lazy val MarkerCPSAdaptMinus = definitions.getClassIfDefined("scala.util.continuations.cpsMinus") + private lazy val MarkerCPSSynth = definitions.getClassIfDefined("scala.util.continuations.cpsSynth") + private lazy val stripTriggerCPSAnns = List(MarkerCPSSynth, MarkerCPSAdaptMinus, MarkerCPSAdaptPlus) + private lazy val MarkerCPSTypes = definitions.getClassIfDefined("scala.util.continuations.cpsParam") + private lazy val strippedCPSAnns = MarkerCPSTypes :: stripTriggerCPSAnns + private def removeCPSAdaptAnnotations(tp: Type) = tp filterAnnotations (ann => !(strippedCPSAnns exists (ann matches _))) + + class MatchTransformer(unit: CompilationUnit) extends TypingTransformer(unit) { + override def transform(tree: Tree): Tree = tree match { + case Match(sel, cases) => + val selX = transform(sel) + val casesX = transformTrees(cases).asInstanceOf[List[CaseDef]] + + val origTp = tree.tpe + val matchX = treeCopy.Match(tree, selX, casesX) + + // when one of the internal cps-type-state annotations is present, strip all CPS annotations + // a cps-type-state-annotated type makes no sense as an expected type (matchX.tpe is used as pt in translateMatch) + // (only test availability of MarkerCPSAdaptPlus assuming they are either all available or none of them are) + if (MarkerCPSAdaptPlus != NoSymbol && (stripTriggerCPSAnns exists tree.tpe.hasAnnotation)) + matchX modifyType removeCPSAdaptAnnotations + + localTyper.typed(translator.translateMatch(matchX)) setType origTp + case Try(block, catches, finalizer) => + treeCopy.Try(tree, transform(block), translator.translateTry(transformTrees(catches).asInstanceOf[List[CaseDef]], tree.tpe, tree.pos), transform(finalizer)) + case _ => super.transform(tree) + } + + def translator: MatchTranslation with CodegenCore = { + new OptimizingMatchTranslator(localTyper) + } + } + + import definitions._ + import analyzer._ //Typer + + val SYNTH_CASE = Flags.CASE | SYNTHETIC + + case class DefaultOverrideMatchAttachment(default: Tree) + + object vpmName { + val one = newTermName("one") + val drop = newTermName("drop") + val flatMap = newTermName("flatMap") + val get = newTermName("get") + val guard = newTermName("guard") + val isEmpty = newTermName("isEmpty") + val orElse = newTermName("orElse") + val outer = newTermName("") + val runOrElse = newTermName("runOrElse") + val zero = newTermName("zero") + val _match = newTermName("__match") // don't call the val __match, since that will trigger virtual pattern matching... + + def counted(str: String, i: Int) = newTermName(str+i) + } + + class PureMatchTranslator(val typer: Typer, val matchStrategy: Tree) extends MatchTranslation with TreeMakers with PureCodegen + class OptimizingMatchTranslator(val typer: Typer) extends MatchTranslation with TreeMakers with MatchOptimizations + +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +// talking to userland +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// + + /** Interface with user-defined match monad? + * if there's a `__match` in scope, we use this as the match strategy, assuming it conforms to MatchStrategy as defined below: + + type Matcher[P[_], M[+_], A] = { + def flatMap[B](f: P[A] => M[B]): M[B] + def orElse[B >: A](alternative: => M[B]): M[B] + } + + abstract class MatchStrategy[P[_], M[+_]] { + // runs the matcher on the given input + def runOrElse[T, U](in: P[T])(matcher: P[T] => M[U]): P[U] + + def zero: M[Nothing] + def one[T](x: P[T]): M[T] + def guard[T](cond: P[Boolean], then: => P[T]): M[T] + def isSuccess[T, U](x: P[T])(f: P[T] => M[U]): P[Boolean] // used for isDefinedAt + } + + * P and M are derived from one's signature (`def one[T](x: P[T]): M[T]`) + + + * if no `__match` is found, we assume the following implementation (and generate optimized code accordingly) + + object __match extends MatchStrategy[({type Id[x] = x})#Id, Option] { + def zero = None + def one[T](x: T) = Some(x) + // NOTE: guard's return type must be of the shape M[T], where M is the monad in which the pattern match should be interpreted + def guard[T](cond: Boolean, then: => T): Option[T] = if(cond) Some(then) else None + def runOrElse[T, U](x: T)(f: T => Option[U]): U = f(x) getOrElse (throw new MatchError(x)) + def isSuccess[T, U](x: T)(f: T => Option[U]): Boolean = !f(x).isEmpty + } + + */ + trait MatchMonadInterface { + val typer: Typer + val matchOwner = typer.context.owner + + def inMatchMonad(tp: Type): Type + def pureType(tp: Type): Type + final def matchMonadResult(tp: Type): Type = + tp.baseType(matchMonadSym).typeArgs match { + case arg :: Nil => arg + case _ => ErrorType + } + + protected def matchMonadSym: Symbol + } + + trait MatchTranslation extends MatchMonadInterface { self: TreeMakers with CodegenCore => + import typer.{typed, context, silent, reallyExists} + // import typer.infer.containsUnchecked + + /** Implement a pattern match by turning its cases (including the implicit failure case) + * into the corresponding (monadic) extractors, and combining them with the `orElse` combinator. + * + * For `scrutinee match { case1 ... caseN }`, the resulting tree has the shape + * `runOrElse(scrutinee)(x => translateCase1(x).orElse(translateCase2(x)).....orElse(zero))` + * + * NOTE: the resulting tree is not type checked, nor are nested pattern matches transformed + * thus, you must typecheck the result (and that will in turn translate nested matches) + * this could probably optimized... (but note that the matchStrategy must be solved for each nested patternmatch) + */ + def translateMatch(match_ : Match): Tree = { + val Match(selector, cases) = match_ + + // we don't transform after uncurry + // (that would require more sophistication when generating trees, + // and the only place that emits Matches after typers is for exception handling anyway) + if(phase.id >= currentRun.uncurryPhase.id) debugwarn("running translateMatch at "+ phase +" on "+ selector +" match "+ cases) + // println("translating "+ cases.mkString("{", "\n", "}")) + + def repeatedToSeq(tp: Type): Type = (tp baseType RepeatedParamClass) match { + case TypeRef(_, RepeatedParamClass, arg :: Nil) => seqType(arg) + case _ => tp + } + + val selectorTp = repeatedToSeq(elimAnonymousClass(selector.tpe.widen.withoutAnnotations)) + val pt0 = match_.tpe + + // we've packed the type for each case in typedMatch so that if all cases have the same existential case, we get a clean lub + // here, we should open up the existential again + // relevant test cases: pos/existentials-harmful.scala, pos/gadt-gilles.scala, pos/t2683.scala, pos/virtpatmat_exist4.scala + // TODO: fix skolemizeExistential (it should preserve annotations, right?) + val pt = repeatedToSeq(pt0.skolemizeExistential(context.owner, context.tree) withAnnotations pt0.annotations) + + // the alternative to attaching the default case override would be to simply + // append the default to the list of cases and suppress the unreachable case error that may arise (once we detect that...) + val matchFailGenOverride = match_ firstAttachment {case DefaultOverrideMatchAttachment(default) => ((scrut: Tree) => default)} + + val selectorSym = freshSym(selector.pos, pureType(selectorTp)) setFlag SYNTH_CASE + // pt = Any* occurs when compiling test/files/pos/annotDepMethType.scala with -Xexperimental + combineCases(selector, selectorSym, cases map translateCase(selectorSym, pt), pt, matchOwner, matchFailGenOverride) + } + + // return list of typed CaseDefs that are supported by the backend (typed/bind/wildcard) + // we don't have a global scrutinee -- the caught exception must be bound in each of the casedefs + // there's no need to check the scrutinee for null -- "throw null" becomes "throw new NullPointerException" + // try to simplify to a type-based switch, or fall back to a catch-all case that runs a normal pattern match + // unlike translateMatch, we type our result before returning it + def translateTry(caseDefs: List[CaseDef], pt: Type, pos: Position): List[CaseDef] = + // if they're already simple enough to be handled by the back-end, we're done + if (caseDefs forall treeInfo.isCatchCase) caseDefs + else { + val swatches = { // switch-catches + val bindersAndCases = caseDefs map { caseDef => + // generate a fresh symbol for each case, hoping we'll end up emitting a type-switch (we don't have a global scrut there) + // if we fail to emit a fine-grained switch, have to do translateCase again with a single scrutSym (TODO: uniformize substitution on treemakers so we can avoid this) + val caseScrutSym = freshSym(pos, pureType(ThrowableClass.tpe)) + (caseScrutSym, propagateSubstitution(translateCase(caseScrutSym, pt)(caseDef), EmptySubstitution)) + } + + for(cases <- emitTypeSwitch(bindersAndCases, pt).toList; + if cases forall treeInfo.isCatchCase; // must check again, since it's not guaranteed -- TODO: can we eliminate this? e.g., a type test could test for a trait or a non-trivial prefix, which are not handled by the back-end + cse <- cases) yield fixerUpper(matchOwner, pos)(cse).asInstanceOf[CaseDef] + } + + val catches = if (swatches.nonEmpty) swatches else { + val scrutSym = freshSym(pos, pureType(ThrowableClass.tpe)) + val casesNoSubstOnly = caseDefs map { caseDef => (propagateSubstitution(translateCase(scrutSym, pt)(caseDef), EmptySubstitution))} + + val exSym = freshSym(pos, pureType(ThrowableClass.tpe), "ex") + + List( + atPos(pos) { + CaseDef( + Bind(exSym, Ident(nme.WILDCARD)), // TODO: does this need fixing upping? + EmptyTree, + combineCasesNoSubstOnly(CODE.REF(exSym), scrutSym, casesNoSubstOnly, pt, matchOwner, Some(scrut => Throw(CODE.REF(exSym)))) + ) + }) + } + + typer.typedCases(catches, ThrowableClass.tpe, WildcardType) + } + + + + /** The translation of `pat if guard => body` has two aspects: + * 1) the substitution due to the variables bound by patterns + * 2) the combination of the extractor calls using `flatMap`. + * + * 2) is easy -- it looks like: `translatePattern_1.flatMap(translatePattern_2....flatMap(translatePattern_N.flatMap(translateGuard.flatMap((x_i) => success(Xbody(x_i)))))...)` + * this must be right-leaning tree, as can be seen intuitively by considering the scope of bound variables: + * variables bound by pat_1 must be visible from the function inside the left-most flatMap right up to Xbody all the way on the right + * 1) is tricky because translatePattern_i determines the shape of translatePattern_i+1: + * zoom in on `translatePattern_1.flatMap(translatePattern_2)` for example -- it actually looks more like: + * `translatePattern_1(x_scrut).flatMap((x_1) => {y_i -> x_1._i}translatePattern_2)` + * + * `x_1` references the result (inside the monad) of the extractor corresponding to `pat_1`, + * this result holds the values for the constructor arguments, which translatePattern_1 has extracted + * from the object pointed to by `x_scrut`. The `y_i` are the symbols bound by `pat_1` (in order) + * in the scope of the remainder of the pattern, and they must thus be replaced by: + * - (for 1-ary unapply) x_1 + * - (for n-ary unapply, n > 1) selection of the i'th tuple component of `x_1` + * - (for unapplySeq) x_1.apply(i) + * + * in the treemakers, + * + * Thus, the result type of `translatePattern_i`'s extractor must conform to `M[(T_1,..., T_n)]`. + * + * Operationally, phase 1) is a foldLeft, since we must consider the depth-first-flattening of + * the transformed patterns from left to right. For every pattern ast node, it produces a transformed ast and + * a function that will take care of binding and substitution of the next ast (to the right). + * + */ + def translateCase(scrutSym: Symbol, pt: Type)(caseDef: CaseDef) = caseDef match { case CaseDef(pattern, guard, body) => + translatePattern(scrutSym, pattern) ++ translateGuard(guard) :+ translateBody(body, pt) + } + + def translatePattern(patBinder: Symbol, patTree: Tree): List[TreeMaker] = { + // a list of TreeMakers that encode `patTree`, and a list of arguments for recursive invocations of `translatePattern` to encode its subpatterns + type TranslationStep = (List[TreeMaker], List[(Symbol, Tree)]) + @inline def withSubPats(treeMakers: List[TreeMaker], subpats: (Symbol, Tree)*): TranslationStep = (treeMakers, subpats.toList) + @inline def noFurtherSubPats(treeMakers: TreeMaker*): TranslationStep = (treeMakers.toList, Nil) + + val pos = patTree.pos + + def translateExtractorPattern(extractor: ExtractorCall): TranslationStep = { + if (!extractor.isTyped) ErrorUtils.issueNormalTypeError(patTree, "Could not typecheck extractor call: "+ extractor)(context) + // if (extractor.resultInMonad == ErrorType) throw new TypeError(pos, "Unsupported extractor type: "+ extractor.tpe) + + // must use type `tp`, which is provided by extractor's result, not the type expected by binder, + // as b.info may be based on a Typed type ascription, which has not been taken into account yet by the translation + // (it will later result in a type test when `tp` is not a subtype of `b.info`) + // TODO: can we simplify this, together with the Bound case? + (extractor.subPatBinders, extractor.subPatTypes).zipped foreach { case (b, tp) => b setInfo tp } // println("changing "+ b +" : "+ b.info +" -> "+ tp); + + // println("translateExtractorPattern checking parameter type: "+ (patBinder, patBinder.info.widen, extractor.paramType, patBinder.info.widen <:< extractor.paramType)) + // example check: List[Int] <:< ::[Int] + // TODO: extractor.paramType may contain unbound type params (run/t2800, run/t3530) + val (typeTestTreeMaker, patBinderOrCasted) = + if (needsTypeTest(patBinder.info.widen, extractor.paramType)) { + // chain a type-testing extractor before the actual extractor call + // it tests the type, checks the outer pointer and casts to the expected type + // TODO: the outer check is mandated by the spec for case classes, but we do it for user-defined unapplies as well [SPEC] + // (the prefix of the argument passed to the unapply must equal the prefix of the type of the binder) + val treeMaker = TypeTestTreeMaker(patBinder, extractor.paramType, pos) + (List(treeMaker), treeMaker.nextBinder) + } else (Nil, patBinder) + + withSubPats(typeTestTreeMaker :+ extractor.treeMaker(patBinderOrCasted, pos), extractor.subBindersAndPatterns: _*) + } + + + object MaybeBoundTyped { + /** Decompose the pattern in `tree`, of shape C(p_1, ..., p_N), into a list of N symbols, and a list of its N sub-trees + * The list of N symbols contains symbols for every bound name as well as the un-named sub-patterns (fresh symbols are generated here for these). + * The returned type is the one inferred by inferTypedPattern (`owntype`) + * + * @arg patBinder symbol used to refer to the result of the previous pattern's extractor (will later be replaced by the outer tree with the correct tree to refer to that patterns result) + */ + def unapply(tree: Tree): Option[(Symbol, Type)] = tree match { + // the Ident subpattern can be ignored, subpatBinder or patBinder tell us all we need to know about it + case Bound(subpatBinder, typed@Typed(Ident(_), tpt)) if typed.tpe ne null => Some((subpatBinder, typed.tpe)) + case Bind(_, typed@Typed(Ident(_), tpt)) if typed.tpe ne null => Some((patBinder, typed.tpe)) + case Typed(Ident(_), tpt) if tree.tpe ne null => Some((patBinder, tree.tpe)) + case _ => None + } + } + + val (treeMakers, subpats) = patTree match { + // skip wildcard trees -- no point in checking them + case WildcardPattern() => noFurtherSubPats() + case UnApply(unfun, args) => + // TODO: check unargs == args + // println("unfun: "+ (unfun.tpe, unfun.symbol.ownerChain, unfun.symbol.info, patBinder.info)) + translateExtractorPattern(ExtractorCall(unfun, args)) + + /** A constructor pattern is of the form c(p1, ..., pn) where n ≥ 0. + It consists of a stable identifier c, followed by element patterns p1, ..., pn. + The constructor c is a simple or qualified name which denotes a case class (§5.3.2). + + If the case class is monomorphic, then it must conform to the expected type of the pattern, + and the formal parameter types of x’s primary constructor (§5.3) are taken as the expected types of the element patterns p1, ..., pn. + + If the case class is polymorphic, then its type parameters are instantiated so that the instantiation of c conforms to the expected type of the pattern. + The instantiated formal parameter types of c’s primary constructor are then taken as the expected types of the component patterns p1, ..., pn. + + The pattern matches all objects created from constructor invocations c(v1, ..., vn) where each element pattern pi matches the corresponding value vi . + A special case arises when c’s formal parameter types end in a repeated parameter. This is further discussed in (§8.1.9). + **/ + case Apply(fun, args) => + ExtractorCall.fromCaseClass(fun, args) map translateExtractorPattern getOrElse { + ErrorUtils.issueNormalTypeError(patTree, "Could not find unapply member for "+ fun +" with args "+ args)(context) + noFurtherSubPats() + } + + /** A typed pattern x : T consists of a pattern variable x and a type pattern T. + The type of x is the type pattern T, where each type variable and wildcard is replaced by a fresh, unknown type. + This pattern matches any value matched by the type pattern T (§8.2); it binds the variable name to that value. + **/ + // must treat Typed and Bind together -- we need to know the patBinder of the Bind pattern to get at the actual type + case MaybeBoundTyped(subPatBinder, pt) => + // a typed pattern never has any subtrees + noFurtherSubPats(TypeAndEqualityTestTreeMaker(subPatBinder, patBinder, pt, pos)) + + /** A pattern binder x@p consists of a pattern variable x and a pattern p. + The type of the variable x is the static type T of the pattern p. + This pattern matches any value v matched by the pattern p, + provided the run-time type of v is also an instance of T, <-- TODO! https://issues.scala-lang.org/browse/SI-1503 + and it binds the variable name to that value. + **/ + case Bound(subpatBinder, p) => + // replace subpatBinder by patBinder (as if the Bind was not there) + withSubPats(List(SubstOnlyTreeMaker(subpatBinder, patBinder)), + // must be patBinder, as subpatBinder has the wrong info: even if the bind assumes a better type, this is not guaranteed until we cast + (patBinder, p) + ) + + /** 8.1.4 Literal Patterns + A literal pattern L matches any value that is equal (in terms of ==) to the literal L. + The type of L must conform to the expected type of the pattern. + + 8.1.5 Stable Identifier Patterns (a stable identifier r (see §3.1)) + The pattern matches any value v such that r == v (§12.1). + The type of r must conform to the expected type of the pattern. + **/ + case Literal(Constant(_)) | Ident(_) | Select(_, _) => + noFurtherSubPats(EqualityTestTreeMaker(patBinder, patTree, pos)) + + case Alternative(alts) => + noFurtherSubPats(AlternativesTreeMaker(patBinder, alts map (translatePattern(patBinder, _)), alts.head.pos)) + + /* TODO: Paul says about future version: I think this should work, and always intended to implement if I can get away with it. + case class Foo(x: Int, y: String) + case class Bar(z: Int) + + def f(x: Any) = x match { case Foo(x, _) | Bar(x) => x } // x is lub of course. + */ + + case Bind(n, p) => // this happens in certain ill-formed programs, there'll be an error later + // println("WARNING: Bind tree with unbound symbol "+ patTree) + noFurtherSubPats() // there's no symbol -- something's wrong... don't fail here though (or should we?) + + // case Star(_) | ArrayValue | This => error("stone age pattern relics encountered!") + + case _ => + error("unsupported pattern: "+ patTree +"(a "+ patTree.getClass +")") + noFurtherSubPats() + } + + treeMakers ++ subpats.flatMap { case (binder, pat) => + translatePattern(binder, pat) // recurse on subpatterns + } + } + + def translateGuard(guard: Tree): List[TreeMaker] = + if (guard == EmptyTree) Nil + else List(GuardTreeMaker(guard)) + + // TODO: 1) if we want to support a generalisation of Kotlin's patmat continue, must not hard-wire lifting into the monad (which is now done by codegen.one), + // so that user can generate failure when needed -- use implicit conversion to lift into monad on-demand? + // to enable this, probably need to move away from Option to a monad specific to pattern-match, + // so that we can return Option's from a match without ambiguity whether this indicates failure in the monad, or just some result in the monad + // 2) body.tpe is the type of the body after applying the substitution that represents the solution of GADT type inference + // need the explicit cast in case our substitutions in the body change the type to something that doesn't take GADT typing into account + def translateBody(body: Tree, matchPt: Type): TreeMaker = + BodyTreeMaker(body, matchPt) + + +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +// helper methods: they analyze types and trees in isolation, but they are not (directly) concerned with the structure of the overall translation +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// + + object ExtractorCall { + def apply(unfun: Tree, args: List[Tree]): ExtractorCall = new ExtractorCallRegular(unfun, args) + + def fromCaseClass(fun: Tree, args: List[Tree]): Option[ExtractorCall] = Some(new ExtractorCallProd(fun, args)) + + // THE PRINCIPLED SLOW PATH -- NOT USED + // generate a call to the (synthetically generated) extractor of a case class + // NOTE: it's an apply, not a select, since in general an extractor call may have multiple argument lists (including an implicit one) + // that we need to preserve, so we supply the scrutinee as Ident(nme.SELECTOR_DUMMY), + // and replace that dummy by a reference to the actual binder in translateExtractorPattern + def fromCaseClassUnapply(fun: Tree, args: List[Tree]): Option[ExtractorCall] = { + // TODO: can we rework the typer so we don't have to do all this twice? + // undo rewrite performed in (5) of adapt + val orig = fun match {case tpt: TypeTree => tpt.original case _ => fun} + val origSym = orig.symbol + val extractor = unapplyMember(origSym.filter(sym => reallyExists(unapplyMember(sym.tpe))).tpe) + + if((fun.tpe eq null) || fun.tpe.isError || (extractor eq NoSymbol)) { + None + } else { + // this is a tricky balance: pos/t602.scala, pos/sudoku.scala, run/virtpatmat_alts.scala must all be happy + // bypass typing at own risk: val extractorCall = Select(orig, extractor) setType caseClassApplyToUnapplyTp(fun.tpe) + // can't always infer type arguments (pos/t602): + /* case class Span[K <: Ordered[K]](low: Option[K]) { + override def equals(x: Any): Boolean = x match { + case Span((low0 @ _)) if low0 equals low => true + } + }*/ + // so... leave undetermined type params floating around if we have to + // (if we don't infer types, uninstantiated type params show up later: pos/sudoku.scala) + // (see also run/virtpatmat_alts.scala) + val savedUndets = context.undetparams + val extractorCall = try { + context.undetparams = Nil + silent(_.typed(Apply(Select(orig, extractor), List(Ident(nme.SELECTOR_DUMMY) setType fun.tpe.finalResultType)), EXPRmode, WildcardType), reportAmbiguousErrors = false) match { + case SilentResultValue(extractorCall) => extractorCall // if !extractorCall.containsError() + case _ => + // this fails to resolve overloading properly... + // Apply(typedOperator(Select(orig, extractor)), List(Ident(nme.SELECTOR_DUMMY))) // no need to set the type of the dummy arg, it will be replaced anyway + + // println("funtpe after = "+ fun.tpe.finalResultType) + // println("orig: "+(orig, orig.tpe)) + val tgt = typed(orig, EXPRmode | QUALmode | POLYmode, HasMember(extractor.name)) // can't specify fun.tpe.finalResultType as the type for the extractor's arg, + // as it may have been inferred incorrectly (see t602, where it's com.mosol.sl.Span[Any], instead of com.mosol.sl.Span[?K]) + // println("tgt = "+ (tgt, tgt.tpe)) + val oper = typed(Select(tgt, extractor.name), EXPRmode | FUNmode | POLYmode | TAPPmode, WildcardType) + // println("oper: "+ (oper, oper.tpe)) + Apply(oper, List(Ident(nme.SELECTOR_DUMMY))) // no need to set the type of the dummy arg, it will be replaced anyway + } + } finally context.undetparams = savedUndets + + Some(this(extractorCall, args)) // TODO: simplify spliceApply? + } + } + } + + abstract class ExtractorCall(val args: List[Tree]) { + val nbSubPats = args.length + + // everything okay, captain? + def isTyped : Boolean + + def isSeq: Boolean + lazy val lastIsStar = (nbSubPats > 0) && treeInfo.isStar(args.last) + + // to which type should the previous binder be casted? + def paramType : Type + + // binder has been casted to paramType if necessary + def treeMaker(binder: Symbol, pos: Position): TreeMaker + + // `subPatBinders` are the variables bound by this pattern in the following patterns + // subPatBinders are replaced by references to the relevant part of the extractor's result (tuple component, seq element, the result as-is) + lazy val subPatBinders = args map { + case Bound(b, p) => b + case p => freshSym(p.pos, prefix = "p") + } + + lazy val subBindersAndPatterns: List[(Symbol, Tree)] = (subPatBinders zip args) map { + case (b, Bound(_, p)) => (b, p) + case bp => bp + } + + def subPatTypes: List[Type] = + if(isSeq) { + val TypeRef(pre, SeqClass, args) = seqTp + // do repeated-parameter expansion to match up with the expected number of arguments (in casu, subpatterns) + formalTypes(rawSubPatTypes.init :+ typeRef(pre, RepeatedParamClass, args), nbSubPats) + } else rawSubPatTypes + + protected def rawSubPatTypes: List[Type] + + protected def seqTp = rawSubPatTypes.last baseType SeqClass + protected def seqLenCmp = rawSubPatTypes.last member nme.lengthCompare + protected lazy val firstIndexingBinder = rawSubPatTypes.length - 1 // rawSubPatTypes.last is the Seq, thus there are `rawSubPatTypes.length - 1` non-seq elements in the tuple + protected lazy val lastIndexingBinder = if(lastIsStar) nbSubPats-2 else nbSubPats-1 + protected lazy val expectedLength = lastIndexingBinder - firstIndexingBinder + 1 + protected lazy val minLenToCheck = if(lastIsStar) 1 else 0 + protected def seqTree(binder: Symbol) = tupleSel(binder)(firstIndexingBinder+1) + protected def tupleSel(binder: Symbol)(i: Int): Tree = codegen.tupleSel(binder)(i) + + // the trees that select the subpatterns on the extractor's result, referenced by `binder` + // require isSeq + protected def subPatRefsSeq(binder: Symbol): List[Tree] = { + val indexingIndices = (0 to (lastIndexingBinder-firstIndexingBinder)) + val nbIndexingIndices = indexingIndices.length + + // this error-condition has already been checked by checkStarPatOK: + // if(isSeq) assert(firstIndexingBinder + nbIndexingIndices + (if(lastIsStar) 1 else 0) == nbSubPats, "(resultInMonad, ts, subPatTypes, subPats)= "+(resultInMonad, ts, subPatTypes, subPats)) + // there are `firstIndexingBinder` non-seq tuple elements preceding the Seq + (((1 to firstIndexingBinder) map tupleSel(binder)) ++ + // then we have to index the binder that represents the sequence for the remaining subpatterns, except for... + (indexingIndices map codegen.index(seqTree(binder))) ++ + // the last one -- if the last subpattern is a sequence wildcard: drop the prefix (indexed by the refs on the line above), return the remainder + (if(!lastIsStar) Nil else List( + if(nbIndexingIndices == 0) seqTree(binder) + else codegen.drop(seqTree(binder))(nbIndexingIndices)))).toList + } + + // the trees that select the subpatterns on the extractor's result, referenced by `binder` + // require (nbSubPats > 0 && (!lastIsStar || isSeq)) + protected def subPatRefs(binder: Symbol): List[Tree] = + if (nbSubPats == 0) Nil + else if (isSeq) subPatRefsSeq(binder) + else ((1 to nbSubPats) map tupleSel(binder)).toList + + protected def lengthGuard(binder: Symbol): Option[Tree] = + // no need to check unless it's an unapplySeq and the minimal length is non-trivially satisfied + if (!isSeq || (expectedLength < minLenToCheck)) None + else { import CODE._ + // `binder.lengthCompare(expectedLength)` + def checkExpectedLength = (seqTree(binder) DOT seqLenCmp)(LIT(expectedLength)) + + // the comparison to perform + // when the last subpattern is a wildcard-star the expectedLength is but a lower bound + // (otherwise equality is required) + def compareOp: (Tree, Tree) => Tree = + if (lastIsStar) _ INT_>= _ + else _ INT_== _ + + // `if (binder != null && $checkExpectedLength [== | >=] 0) then else zero` + Some((seqTree(binder) ANY_!= NULL) AND compareOp(checkExpectedLength, ZERO)) + } + } + + // TODO: to be called when there's a def unapplyProd(x: T): U + // U must have N members _1,..., _N -- the _i are type checked, call their type Ti, + // + // for now only used for case classes -- pretending there's an unapplyProd that's the identity (and don't call it) + class ExtractorCallProd(fun: Tree, args: List[Tree]) extends ExtractorCall(args) { + // TODO: fix the illegal type bound in pos/t602 -- type inference messes up before we get here: + /*override def equals(x$1: Any): Boolean = ... + val o5: Option[com.mosol.sl.Span[Any]] = // Span[Any] --> Any is not a legal type argument for Span! + */ + // private val orig = fun match {case tpt: TypeTree => tpt.original case _ => fun} + // private val origExtractorTp = unapplyMember(orig.symbol.filter(sym => reallyExists(unapplyMember(sym.tpe))).tpe).tpe + // private val extractorTp = if (wellKinded(fun.tpe)) fun.tpe else existentialAbstraction(origExtractorTp.typeParams, origExtractorTp.resultType) + // println("ExtractorCallProd: "+ (fun.tpe, existentialAbstraction(origExtractorTp.typeParams, origExtractorTp.resultType))) + // println("ExtractorCallProd: "+ (fun.tpe, args map (_.tpe))) + private def constructorTp = fun.tpe + + def isTyped = fun.isTyped + + // to which type should the previous binder be casted? + def paramType = constructorTp.finalResultType + + def isSeq: Boolean = rawSubPatTypes.nonEmpty && isRepeatedParamType(rawSubPatTypes.last) + protected def rawSubPatTypes = constructorTp.paramTypes + + // binder has type paramType + def treeMaker(binder: Symbol, pos: Position): TreeMaker = { + // checks binder ne null before chaining to the next extractor + ProductExtractorTreeMaker(binder, lengthGuard(binder), Substitution(subPatBinders, subPatRefs(binder))) + } + + // reference the (i-1)th case accessor if it exists, otherwise the (i-1)th tuple component + override protected def tupleSel(binder: Symbol)(i: Int): Tree = { import CODE._ + // caseFieldAccessors is messed up after typers (reversed, names mangled for non-public fields) + // TODO: figure out why... + val accessors = binder.caseFieldAccessors + // luckily, the constrParamAccessors are still sorted properly, so sort the field-accessors using them + // (need to undo name-mangling, including the sneaky trailing whitespace) + val constrParamAccessors = binder.constrParamAccessors + + def indexInCPA(acc: Symbol) = + constrParamAccessors indexWhere { orig => + // println("compare: "+ (orig, acc, orig.name, acc.name, (acc.name == orig.name), (acc.name startsWith (orig.name append "$")))) + val origName = orig.name.toString.trim + val accName = acc.name.toString.trim + (accName == origName) || (accName startsWith (origName + "$")) + } + + // println("caseFieldAccessors: "+ (accessors, binder.caseFieldAccessors map indexInCPA)) + // println("constrParamAccessors: "+ constrParamAccessors) + + val accessorsSorted = accessors sortBy indexInCPA + if (accessorsSorted isDefinedAt (i-1)) REF(binder) DOT accessorsSorted(i-1) + else codegen.tupleSel(binder)(i) // this won't type check for case classes, as they do not inherit ProductN + } + + override def toString(): String = "case class "+ (if (constructorTp eq null) fun else paramType.typeSymbol) +" with arguments "+ args + } + + class ExtractorCallRegular(extractorCallIncludingDummy: Tree, args: List[Tree]) extends ExtractorCall(args) { + private lazy val Some(Apply(extractorCall, _)) = extractorCallIncludingDummy.find{ case Apply(_, List(Ident(nme.SELECTOR_DUMMY))) => true case _ => false } + + def tpe = extractorCall.tpe + def isTyped = (tpe ne NoType) && extractorCall.isTyped && (resultInMonad ne ErrorType) + def paramType = tpe.paramTypes.head + def resultType = tpe.finalResultType + def isSeq = extractorCall.symbol.name == nme.unapplySeq + + def treeMaker(patBinderOrCasted: Symbol, pos: Position): TreeMaker = { + // the extractor call (applied to the binder bound by the flatMap corresponding to the previous (i.e., enclosing/outer) pattern) + val extractorApply = atPos(pos)(spliceApply(patBinderOrCasted)) + val binder = freshSym(pos, pureType(resultInMonad)) // can't simplify this when subPatBinders.isEmpty, since UnitClass.tpe is definitely wrong when isSeq, and resultInMonad should always be correct since it comes directly from the extractor's result type + ExtractorTreeMaker(extractorApply, lengthGuard(binder), binder, Substitution(subPatBinders, subPatRefs(binder)))(resultType.typeSymbol == BooleanClass) + } + + override protected def seqTree(binder: Symbol): Tree = + if (firstIndexingBinder == 0) CODE.REF(binder) + else super.seqTree(binder) + + // the trees that select the subpatterns on the extractor's result, referenced by `binder` + // require (nbSubPats > 0 && (!lastIsStar || isSeq)) + override protected def subPatRefs(binder: Symbol): List[Tree] = + if (!isSeq && nbSubPats == 1) List(CODE.REF(binder)) // special case for extractors + else super.subPatRefs(binder) + + protected def spliceApply(binder: Symbol): Tree = { + object splice extends Transformer { + override def transform(t: Tree) = t match { + case Apply(x, List(Ident(nme.SELECTOR_DUMMY))) => + treeCopy.Apply(t, x, List(CODE.REF(binder))) + case _ => super.transform(t) + } + } + splice.transform(extractorCallIncludingDummy) + } + + // what's the extractor's result type in the monad? + // turn an extractor's result type into something `monadTypeToSubPatTypesAndRefs` understands + protected lazy val resultInMonad: Type = if(!hasLength(tpe.paramTypes, 1)) ErrorType else { + if (resultType.typeSymbol == BooleanClass) UnitClass.tpe + else matchMonadResult(resultType) + } + + protected lazy val rawSubPatTypes = + if (resultInMonad.typeSymbol eq UnitClass) Nil + else if(nbSubPats == 1) List(resultInMonad) + else getProductArgs(resultInMonad) match { + case Nil => List(resultInMonad) + case x => x + } + + override def toString() = extractorCall +": "+ extractorCall.tpe +" (symbol= "+ extractorCall.symbol +")." + } + + /** A conservative approximation of which patterns do not discern anything. + * They are discarded during the translation. + */ + object WildcardPattern { + def unapply(pat: Tree): Boolean = pat match { + case Bind(nme.WILDCARD, WildcardPattern()) => true // don't skip when binding an interesting symbol! + case Ident(nme.WILDCARD) => true + case Star(WildcardPattern()) => true + case x: Ident => treeInfo.isVarPattern(x) + case Alternative(ps) => ps forall (WildcardPattern.unapply(_)) + case EmptyTree => true + case _ => false + } + } + + object Bound { + def unapply(t: Tree): Option[(Symbol, Tree)] = t match { + case t@Bind(n, p) if (t.symbol ne null) && (t.symbol ne NoSymbol) => // pos/t2429 does not satisfy these conditions + Some((t.symbol, p)) + case _ => None + } + } + } + +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +// substitution +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// + trait TypedSubstitution extends MatchMonadInterface { + object Substitution { + def apply(from: Symbol, to: Tree) = new Substitution(List(from), List(to)) + // requires sameLength(from, to) + def apply(from: List[Symbol], to: List[Tree]) = + if (from nonEmpty) new Substitution(from, to) else EmptySubstitution + } + + class Substitution(val from: List[Symbol], val to: List[Tree]) { + // We must explicitly type the trees that we replace inside some other tree, since the latter may already have been typed, + // and will thus not be retyped. This means we might end up with untyped subtrees inside bigger, typed trees. + def apply(tree: Tree): Tree = { + // according to -Ystatistics 10% of translateMatch's time is spent in this method... + // since about half of the typedSubst's end up being no-ops, the check below shaves off 5% of the time spent in typedSubst + if (!tree.exists { case i@Ident(_) => from contains i.symbol case _ => false}) tree + else (new Transformer { + @inline private def typedIfOrigTyped(to: Tree, origTp: Type): Tree = + if (origTp == null || origTp == NoType) to + // important: only type when actually substing and when original tree was typed + // (don't need to use origTp as the expected type, though, and can't always do this anyway due to unknown type params stemming from polymorphic extractors) + else typer.typed(to, EXPRmode, WildcardType) + + override def transform(tree: Tree): Tree = { + def subst(from: List[Symbol], to: List[Tree]): Tree = + if (from.isEmpty) tree + else if (tree.symbol == from.head) typedIfOrigTyped(to.head.shallowDuplicate, tree.tpe) + else subst(from.tail, to.tail) + + tree match { + case Ident(_) => subst(from, to) + case _ => super.transform(tree) + } + } + }).transform(tree) + } + + + // the substitution that chains `other` before `this` substitution + // forall t: Tree. this(other(t)) == (this >> other)(t) + def >>(other: Substitution): Substitution = { + val (fromFiltered, toFiltered) = (from, to).zipped filter { (f, t) => !other.from.contains(f) } + new Substitution(other.from ++ fromFiltered, other.to.map(apply) ++ toFiltered) // a quick benchmarking run indicates the `.map(apply)` is not too costly + } + override def toString = (from zip to) mkString("Substitution(", ", ", ")") + } + + object EmptySubstitution extends Substitution(Nil, Nil) { + override def apply(tree: Tree): Tree = tree + override def >>(other: Substitution): Substitution = other + } + } + +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +// the making of the trees +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// + trait TreeMakers extends TypedSubstitution { self: CodegenCore => + def optimizeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type): (List[List[TreeMaker]], List[Tree]) = + (cases, Nil) + + def emitSwitch(scrut: Tree, scrutSym: Symbol, cases: List[List[TreeMaker]], pt: Type, matchFailGenOverride: Option[Tree => Tree]): Option[Tree] = + None + + // for catch (no need to customize match failure) + def emitTypeSwitch(bindersAndCases: List[(Symbol, List[TreeMaker])], pt: Type): Option[List[CaseDef]] = + None + + abstract class TreeMaker { + /** captures the scope and the value of the bindings in patterns + * important *when* the substitution happens (can't accumulate and do at once after the full matcher has been constructed) + */ + def substitution: Substitution = + if (currSub eq null) localSubstitution + else currSub + + protected def localSubstitution: Substitution + + private[TreeMakers] def incorporateOuterSubstitution(outerSubst: Substitution): Unit = { + if (currSub ne null) { + println("BUG: incorporateOuterSubstitution called more than once for "+ (this, currSub, outerSubst)) + Thread.dumpStack() + } + else currSub = outerSubst >> substitution + } + private[this] var currSub: Substitution = null + + // build Tree that chains `next` after the current extractor + def chainBefore(next: Tree)(casegen: Casegen): Tree + } + + trait NoNewBinders extends TreeMaker { + protected val localSubstitution: Substitution = EmptySubstitution + } + + case class TrivialTreeMaker(tree: Tree) extends TreeMaker with NoNewBinders { + def chainBefore(next: Tree)(casegen: Casegen): Tree = tree + } + + case class BodyTreeMaker(body: Tree, matchPt: Type) extends TreeMaker with NoNewBinders { + def chainBefore(next: Tree)(casegen: Casegen): Tree = // assert(next eq EmptyTree) + atPos(body.pos)(casegen.one(substitution(body))) // since SubstOnly treemakers are dropped, need to do it here + } + + case class SubstOnlyTreeMaker(prevBinder: Symbol, nextBinder: Symbol) extends TreeMaker { + val localSubstitution = Substitution(prevBinder, CODE.REF(nextBinder)) + def chainBefore(next: Tree)(casegen: Casegen): Tree = substitution(next) + } + + abstract class FunTreeMaker extends TreeMaker { + val nextBinder: Symbol + } + + abstract class CondTreeMaker extends FunTreeMaker { + val pos: Position + val prevBinder: Symbol + val nextBinderTp: Type + val cond: Tree + val res: Tree + + lazy val nextBinder = freshSym(pos, nextBinderTp) + lazy val localSubstitution = Substitution(List(prevBinder), List(CODE.REF(nextBinder))) + + def chainBefore(next: Tree)(casegen: Casegen): Tree = + atPos(pos)(casegen.flatMapCond(cond, res, nextBinder, substitution(next))) + } + + /** + * Make a TreeMaker that will result in an extractor call specified by `extractor` + * the next TreeMaker (here, we don't know which it'll be) is chained after this one by flatMap'ing + * a function with binder `nextBinder` over our extractor's result + * the function's body is determined by the next TreeMaker + * in this function's body, and all the subsequent ones, references to the symbols in `from` will be replaced by the corresponding tree in `to` + */ + case class ExtractorTreeMaker(extractor: Tree, extraCond: Option[Tree], nextBinder: Symbol, localSubstitution: Substitution)(extractorReturnsBoolean: Boolean) extends FunTreeMaker { + def chainBefore(next: Tree)(casegen: Casegen): Tree = { + val condAndNext = extraCond map (casegen.ifThenElseZero(_, next)) getOrElse next + atPos(extractor.pos)( + if (extractorReturnsBoolean) casegen.flatMapCond(extractor, CODE.UNIT, nextBinder, substitution(condAndNext)) + else casegen.flatMap(extractor, nextBinder, substitution(condAndNext)) + ) + } + + override def toString = "X"+(extractor, nextBinder) + } + + // TODO: allow user-defined unapplyProduct + case class ProductExtractorTreeMaker(prevBinder: Symbol, extraCond: Option[Tree], localSubstitution: Substitution) extends TreeMaker { import CODE._ + def chainBefore(next: Tree)(casegen: Casegen): Tree = { + val nullCheck = REF(prevBinder) OBJ_NE NULL + val cond = extraCond map (nullCheck AND _) getOrElse nullCheck + casegen.ifThenElseZero(cond, substitution(next)) + } + + override def toString = "P"+(prevBinder, extraCond getOrElse "", localSubstitution) + } + + // tack an outer test onto `cond` if binder.info and expectedType warrant it + def maybeWithOuterCheck(binder: Symbol, expectedTp: Type)(cond: Tree): Tree = { import CODE._ + if ( !((expectedTp.prefix eq NoPrefix) || expectedTp.prefix.typeSymbol.isPackageClass) + && needsOuterTest(expectedTp, binder.info, matchOwner)) { + val expectedPrefix = expectedTp.prefix match { + case ThisType(clazz) => THIS(clazz) + case pre => REF(pre.prefix, pre.termSymbol) + } + + // ExplicitOuter replaces `Select(q, outerSym) OBJ_EQ expectedPrefix` by `Select(q, outerAccessor(outerSym.owner)) OBJ_EQ expectedPrefix` + // if there's an outer accessor, otherwise the condition becomes `true` -- TODO: can we improve needsOuterTest so there's always an outerAccessor? + val outer = expectedTp.typeSymbol.newMethod(vpmName.outer) setInfo expectedTp.prefix setFlag SYNTHETIC + val outerCheck = (Select(codegen._asInstanceOf(binder, expectedTp), outer)) OBJ_EQ expectedPrefix + + // first check cond, since that should ensure we're not selecting outer on null + codegen.and(cond, outerCheck) + } + else + cond + } + + // containsUnchecked: also need to test when erasing pt loses crucial information (maybe we can recover it using a TypeTag) + def needsTypeTest(tp: Type, pt: Type): Boolean = !(tp <:< pt) // || containsUnchecked(pt) + // TODO: try to find the TypeTag for the binder's type and the expected type, and if they exists, + // check that the TypeTag of the binder's type conforms to the TypeTag of the expected type + private def typeTest(binderToTest: Symbol, expectedTp: Type, disableOuterCheck: Boolean = false, dynamic: Boolean = false): Tree = { import CODE._ + // def coreTest = + if (disableOuterCheck) codegen._isInstanceOf(binderToTest, expectedTp) else maybeWithOuterCheck(binderToTest, expectedTp)(codegen._isInstanceOf(binderToTest, expectedTp)) + // [Eugene to Adriaan] use `resolveErasureTag` instead of `findManifest`. please, provide a meaningful position + // if (opt.experimental && containsUnchecked(expectedTp)) { + // if (dynamic) { + // val expectedTpTagTree = findManifest(expectedTp, true) + // if (!expectedTpTagTree.isEmpty) + // ((expectedTpTagTree DOT "erasure".toTermName) DOT "isAssignableFrom".toTermName)(REF(binderToTest) DOT nme.getClass_) + // else + // coreTest + // } else { + // val expectedTpTagTree = findManifest(expectedTp, true) + // val binderTpTagTree = findManifest(binderToTest.info, true) + // if(!(expectedTpTagTree.isEmpty || binderTpTagTree.isEmpty)) + // coreTest AND (binderTpTagTree DOT nme.CONFORMS)(expectedTpTagTree) + // else + // coreTest + // } + // } else coreTest + } + + // need to substitute since binder may be used outside of the next extractor call (say, in the body of the case) + case class TypeTestTreeMaker(prevBinder: Symbol, nextBinderTp: Type, pos: Position) extends CondTreeMaker { + val cond = typeTest(prevBinder, nextBinderTp, dynamic = true) + val res = codegen._asInstanceOf(prevBinder, nextBinderTp) + override def toString = "TT"+(prevBinder, nextBinderTp) + } + + // implements the run-time aspects of (§8.2) (typedPattern has already done the necessary type transformations) + // TODO: normalize construction, which yields a combination of a EqualityTestTreeMaker (when necessary) and a TypeTestTreeMaker + case class TypeAndEqualityTestTreeMaker(prevBinder: Symbol, patBinder: Symbol, pt: Type, pos: Position) extends CondTreeMaker { + val nextBinderTp = glb(List(patBinder.info.widen, pt)) + + /** Type patterns consist of types, type variables, and wildcards. A type pattern T is of one of the following forms: + - A reference to a class C, p.C, or T#C. + This type pattern matches any non-null instance of the given class. + Note that the prefix of the class, if it is given, is relevant for determining class instances. + For instance, the pattern p.C matches only instances of classes C which were created with the path p as prefix. + The bottom types scala.Nothing and scala.Null cannot be used as type patterns, because they would match nothing in any case. + + - A singleton type p.type. + This type pattern matches only the value denoted by the path p + (that is, a pattern match involved a comparison of the matched value with p using method eq in class AnyRef). // TODO: the actual pattern matcher uses ==, so that's what I'm using for now + // https://issues.scala-lang.org/browse/SI-4577 "pattern matcher, still disappointing us at equality time" + + - A compound type pattern T1 with ... with Tn where each Ti is a type pat- tern. + This type pattern matches all values that are matched by each of the type patterns Ti. + + - A parameterized type pattern T[a1,...,an], where the ai are type variable patterns or wildcards _. + This type pattern matches all values which match T for some arbitrary instantiation of the type variables and wildcards. + The bounds or alias type of these type variable are determined as described in (§8.3). + + - A parameterized type pattern scala.Array[T1], where T1 is a type pattern. // TODO + This type pattern matches any non-null instance of type scala.Array[U1], where U1 is a type matched by T1. + **/ + + // generate the tree for the run-time test that follows from the fact that + // a `scrut` of known type `scrutTp` is expected to have type `expectedTp` + // uses maybeWithOuterCheck to check the type's prefix + private def typeAndEqualityTest(patBinder: Symbol, pt: Type): Tree = { import CODE._ + // TODO: `null match { x : T }` will yield a check that (indirectly) tests whether `null ne null` + // don't bother (so that we don't end up with the warning "comparing values of types Null and Null using `ne' will always yield false") + def genEqualsAndInstanceOf(sym: Symbol): Tree + = codegen._equals(REF(sym), patBinder) AND typeTest(patBinder, pt.widen, disableOuterCheck = true) + + def isRefTp(tp: Type) = tp <:< AnyRefClass.tpe + + val patBinderTp = patBinder.info.widen + def isMatchUnlessNull = isRefTp(pt) && !needsTypeTest(patBinderTp, pt) + + // TODO: [SPEC] type test for Array + // TODO: use TypeTags to improve tests (for erased types we can do better when we have a TypeTag) + pt match { + case SingleType(_, sym) /*this implies sym.isStable*/ => genEqualsAndInstanceOf(sym) // TODO: [SPEC] the spec requires `eq` instead of `==` here + case ThisType(sym) if sym.isModule => genEqualsAndInstanceOf(sym) // must use == to support e.g. List() == Nil + case ThisType(sym) => REF(patBinder) OBJ_EQ This(sym) + case ConstantType(Constant(null)) if isRefTp(patBinderTp) => REF(patBinder) OBJ_EQ NULL + case ConstantType(const) => codegen._equals(Literal(const), patBinder) + case _ if isMatchUnlessNull => maybeWithOuterCheck(patBinder, pt)(REF(patBinder) OBJ_NE NULL) + case _ => typeTest(patBinder, pt) + } + } + + val cond = typeAndEqualityTest(patBinder, pt) + val res = codegen._asInstanceOf(patBinder, nextBinderTp) + + // TODO: remove this + def isStraightTypeTest = cond match { case TypeApply(_, _) => cond.symbol == Any_isInstanceOf case _ => false } + + override def toString = "TET"+(patBinder, pt) + } + + // need to substitute to deal with existential types -- TODO: deal with existentials better, don't substitute (see RichClass during quick.comp) + case class EqualityTestTreeMaker(prevBinder: Symbol, patTree: Tree, pos: Position) extends CondTreeMaker { + val nextBinderTp = prevBinder.info.widen + + // NOTE: generate `patTree == patBinder`, since the extractor must be in control of the equals method (also, patBinder may be null) + // equals need not be well-behaved, so don't intersect with pattern's (stabilized) type (unlike MaybeBoundTyped's accumType, where it's required) + val cond = codegen._equals(patTree, prevBinder) + val res = CODE.REF(prevBinder) + override def toString = "ET"+(prevBinder, patTree) + } + + case class AlternativesTreeMaker(prevBinder: Symbol, var altss: List[List[TreeMaker]], pos: Position) extends TreeMaker with NoNewBinders { + // don't substitute prevBinder to nextBinder, a set of alternatives does not need to introduce a new binder, simply reuse the previous one + + override private[TreeMakers] def incorporateOuterSubstitution(outerSubst: Substitution): Unit = { + super.incorporateOuterSubstitution(outerSubst) + altss = altss map (alts => propagateSubstitution(alts, substitution)) + } + + def chainBefore(next: Tree)(codegenAlt: Casegen): Tree = { import CODE._ + atPos(pos){ + // one alternative may still generate multiple trees (e.g., an extractor call + equality test) + // (for now,) alternatives may not bind variables (except wildcards), so we don't care about the final substitution built internally by makeTreeMakers + val combinedAlts = altss map (altTreeMakers => + ((casegen: Casegen) => combineExtractors(altTreeMakers :+ TrivialTreeMaker(casegen.one(TRUE_typed)))(casegen)) + ) + + val findAltMatcher = codegenAlt.matcher(EmptyTree, NoSymbol, BooleanClass.tpe)(combinedAlts, Some(x => FALSE_typed)) + codegenAlt.ifThenElseZero(findAltMatcher, substitution(next)) + } + } + } + + case class GuardTreeMaker(guardTree: Tree) extends TreeMaker with NoNewBinders { + def chainBefore(next: Tree)(casegen: Casegen): Tree = casegen.flatMapGuard(substitution(guardTree), next) + override def toString = "G("+ guardTree +")" + } + + // combineExtractors changes the current substitution's of the tree makers in `treeMakers` + // requires propagateSubstitution(treeMakers) has been called + def combineExtractors(treeMakers: List[TreeMaker])(casegen: Casegen): Tree = + treeMakers.foldRight(EmptyTree: Tree)((a, b) => a.chainBefore(b)(casegen)) + + + def removeSubstOnly(makers: List[TreeMaker]) = makers filterNot (_.isInstanceOf[SubstOnlyTreeMaker]) + + // a foldLeft to accumulate the localSubstitution left-to-right + // it drops SubstOnly tree makers, since their only goal in life is to propagate substitutions to the next tree maker, which is fullfilled by propagateSubstitution + def propagateSubstitution(treeMakers: List[TreeMaker], initial: Substitution): List[TreeMaker] = { + var accumSubst: Substitution = initial + treeMakers foreach { maker => + maker incorporateOuterSubstitution accumSubst + accumSubst = maker.substitution + } + removeSubstOnly(treeMakers) + } + + // calls propagateSubstitution on the treemakers + def combineCases(scrut: Tree, scrutSym: Symbol, casesRaw: List[List[TreeMaker]], pt: Type, owner: Symbol, matchFailGenOverride: Option[Tree => Tree]): Tree = { + // drops SubstOnlyTreeMakers, since their effect is now contained in the TreeMakers that follow them + val casesNoSubstOnly = casesRaw map (propagateSubstitution(_, EmptySubstitution)) + combineCasesNoSubstOnly(scrut, scrutSym, casesNoSubstOnly, pt, owner, matchFailGenOverride) + } + + def combineCasesNoSubstOnly(scrut: Tree, scrutSym: Symbol, casesNoSubstOnly: List[List[TreeMaker]], pt: Type, owner: Symbol, matchFailGenOverride: Option[Tree => Tree]): Tree = + fixerUpper(owner, scrut.pos){ + val ptDefined = if (isFullyDefined(pt)) pt else NoType + def matchFailGen = (matchFailGenOverride orElse Some(CODE.MATCHERROR(_: Tree))) + // println("combining cases: "+ (casesNoSubstOnly.map(_.mkString(" >> ")).mkString("{", "\n", "}"))) + + emitSwitch(scrut, scrutSym, casesNoSubstOnly, pt, matchFailGenOverride).getOrElse{ + if (casesNoSubstOnly nonEmpty) { + // before optimizing, check casesNoSubstOnly for presence of a default case, + // since DCE will eliminate trivial cases like `case _ =>`, even if they're the last one + // exhaustivity and reachability must be checked before optimization as well + // TODO: improve notion of trivial/irrefutable -- a trivial type test before the body still makes for a default case + // ("trivial" depends on whether we're emitting a straight match or an exception, or more generally, any supertype of scrutSym.tpe is a no-op) + // irrefutability checking should use the approximation framework also used for CSE, unreachability and exhaustivity checking + val synthCatchAll = + if (casesNoSubstOnly.nonEmpty && { + val nonTrivLast = casesNoSubstOnly.last + nonTrivLast.nonEmpty && nonTrivLast.head.isInstanceOf[BodyTreeMaker] + }) None + else matchFailGen + + val (cases, toHoist) = optimizeCases(scrutSym, casesNoSubstOnly, pt) + + val matchRes = codegen.matcher(scrut, scrutSym, pt)(cases map combineExtractors, synthCatchAll) + + if (toHoist isEmpty) matchRes else Block(toHoist, matchRes) + } else { + codegen.matcher(scrut, scrutSym, pt)(Nil, matchFailGen) + } + } + } + + // TODO: do this during tree construction, but that will require tracking the current owner in treemakers + // TODO: assign more fine-grained positions + // fixes symbol nesting, assigns positions + protected def fixerUpper(origOwner: Symbol, pos: Position) = new Traverser { + currentOwner = origOwner + + override def traverse(t: Tree) { + if (t != EmptyTree && t.pos == NoPosition) { + t.setPos(pos) + } + t match { + case Function(_, _) if t.symbol == NoSymbol => + t.symbol = currentOwner.newAnonymousFunctionValue(t.pos) + // println("new symbol for "+ (t, t.symbol.ownerChain)) + case Function(_, _) if (t.symbol.owner == NoSymbol) || (t.symbol.owner == origOwner) => + // println("fundef: "+ (t, t.symbol.ownerChain, currentOwner.ownerChain)) + t.symbol.owner = currentOwner + case d : DefTree if (d.symbol != NoSymbol) && ((d.symbol.owner == NoSymbol) || (d.symbol.owner == origOwner)) => // don't indiscriminately change existing owners! (see e.g., pos/t3440, pos/t3534, pos/unapplyContexts2) + // println("def: "+ (d, d.symbol.ownerChain, currentOwner.ownerChain)) + if(d.symbol.isLazy) { // for lazy val's accessor -- is there no tree?? + assert(d.symbol.lazyAccessor != NoSymbol && d.symbol.lazyAccessor.owner == d.symbol.owner, d.symbol.lazyAccessor) + d.symbol.lazyAccessor.owner = currentOwner + } + if(d.symbol.moduleClass ne NoSymbol) + d.symbol.moduleClass.owner = currentOwner + + d.symbol.owner = currentOwner + // case _ if (t.symbol != NoSymbol) && (t.symbol ne null) => + // println("untouched "+ (t, t.getClass, t.symbol.ownerChain, currentOwner.ownerChain)) + case _ => + } + super.traverse(t) + } + + // override def apply + // println("before fixerupper: "+ xTree) + // currentRun.trackerFactory.snapshot() + // println("after fixerupper") + // currentRun.trackerFactory.snapshot() + } + } + + +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +// generate actual trees +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// + trait CodegenCore extends MatchMonadInterface { + private var ctr = 0 + def freshName(prefix: String) = {ctr += 1; vpmName.counted(prefix, ctr)} + + // assert(owner ne null); assert(owner ne NoSymbol) + def freshSym(pos: Position, tp: Type = NoType, prefix: String = "x") = + NoSymbol.newTermSymbol(freshName(prefix), pos) setInfo tp + + // codegen relevant to the structure of the translation (how extractors are combined) + trait AbsCodegen { + def matcher(scrut: Tree, scrutSym: Symbol, restpe: Type)(cases: List[Casegen => Tree], matchFailGen: Option[Tree => Tree]): Tree + + // local / context-free + def _asInstanceOf(b: Symbol, tp: Type): Tree + def _equals(checker: Tree, binder: Symbol): Tree + def _isInstanceOf(b: Symbol, tp: Type): Tree + def and(a: Tree, b: Tree): Tree + def drop(tgt: Tree)(n: Int): Tree + def index(tgt: Tree)(i: Int): Tree + def mkZero(tp: Type): Tree + def tupleSel(binder: Symbol)(i: Int): Tree + } + + // structure + trait Casegen extends AbsCodegen { import CODE._ + def one(res: Tree): Tree + + def flatMap(prev: Tree, b: Symbol, next: Tree): Tree + def flatMapCond(cond: Tree, res: Tree, nextBinder: Symbol, next: Tree): Tree + def flatMapGuard(cond: Tree, next: Tree): Tree + def ifThenElseZero(c: Tree, then: Tree): Tree = IF (c) THEN then ELSE zero + protected def zero: Tree + } + + def codegen: AbsCodegen + + def typesConform(tp: Type, pt: Type) = ((tp eq pt) || (tp <:< pt)) + + abstract class CommonCodegen extends AbsCodegen { import CODE._ + def fun(arg: Symbol, body: Tree): Tree = Function(List(ValDef(arg)), body) + def genTypeApply(tfun: Tree, args: Type*): Tree = if(args contains NoType) tfun else TypeApply(tfun, args.toList map TypeTree) + def tupleSel(binder: Symbol)(i: Int): Tree = (REF(binder) DOT nme.productAccessorName(i)) // make tree that accesses the i'th component of the tuple referenced by binder + def index(tgt: Tree)(i: Int): Tree = tgt APPLY (LIT(i)) + def drop(tgt: Tree)(n: Int): Tree = (tgt DOT vpmName.drop) (LIT(n)) + def _equals(checker: Tree, binder: Symbol): Tree = checker MEMBER_== REF(binder) // NOTE: checker must be the target of the ==, that's the patmat semantics for ya + def and(a: Tree, b: Tree): Tree = a AND b + + // drop annotations generated by CPS plugin etc, since its annotationchecker rejects T @cps[U] <: Any + // let's assume for now annotations don't affect casts, drop them there, and bring them back using the outer Typed tree + private def mkCast(t: Tree, tp: Type) = + Typed(gen.mkAsInstanceOf(t, tp.withoutAnnotations, true, false), TypeTree() setType tp) + + // the force is needed mainly to deal with the GADT typing hack (we can't detect it otherwise as tp nor pt need contain an abstract type, we're just casting wildly) + def _asInstanceOf(t: Tree, tp: Type, force: Boolean = false): Tree = if (!force && (t.tpe ne NoType) && t.isTyped && typesConform(t.tpe, tp)) t else mkCast(t, tp) + def _asInstanceOf(b: Symbol, tp: Type): Tree = if (typesConform(b.info, tp)) REF(b) else mkCast(REF(b), tp) + def _isInstanceOf(b: Symbol, tp: Type): Tree = gen.mkIsInstanceOf(REF(b), tp.withoutAnnotations, true, false) + // if (typesConform(b.info, tpX)) { println("warning: emitted spurious isInstanceOf: "+(b, tp)); TRUE } + + // duplicated out of frustration with cast generation + def mkZero(tp: Type): Tree = { + tp.typeSymbol match { + case UnitClass => Literal(Constant()) + case BooleanClass => Literal(Constant(false)) + case FloatClass => Literal(Constant(0.0f)) + case DoubleClass => Literal(Constant(0.0d)) + case ByteClass => Literal(Constant(0.toByte)) + case ShortClass => Literal(Constant(0.toShort)) + case IntClass => Literal(Constant(0)) + case LongClass => Literal(Constant(0L)) + case CharClass => Literal(Constant(0.toChar)) + case _ => gen.mkAsInstanceOf(Literal(Constant(null)), tp, any = true, wrapInApply = false) // the magic incantation is true/false here + } + } + } + } + + trait PureMatchMonadInterface extends MatchMonadInterface { + val matchStrategy: Tree + + def inMatchMonad(tp: Type): Type = appliedType(oneSig, List(tp)).finalResultType + def pureType(tp: Type): Type = appliedType(oneSig, List(tp)).paramTypes.headOption getOrElse NoType // fail gracefully (otherwise we get crashes) + protected def matchMonadSym = oneSig.finalResultType.typeSymbol + + import CODE._ + def _match(n: Name): SelectStart = matchStrategy DOT n + + private lazy val oneSig: Type = + typer.typed(_match(vpmName.one), EXPRmode | POLYmode | TAPPmode | FUNmode, WildcardType).tpe // TODO: error message + } + + trait PureCodegen extends CodegenCore with PureMatchMonadInterface { + def codegen: AbsCodegen = pureCodegen + + object pureCodegen extends CommonCodegen with Casegen { import CODE._ + //// methods in MatchingStrategy (the monad companion) -- used directly in translation + // __match.runOrElse(`scrut`)(`scrutSym` => `matcher`) + // TODO: consider catchAll, or virtualized matching will break in exception handlers + def matcher(scrut: Tree, scrutSym: Symbol, restpe: Type)(cases: List[Casegen => Tree], matchFailGen: Option[Tree => Tree]): Tree = + _match(vpmName.runOrElse) APPLY (scrut) APPLY (fun(scrutSym, cases map (f => f(this)) reduceLeft typedOrElse)) + + // __match.one(`res`) + def one(res: Tree): Tree = (_match(vpmName.one)) (res) + // __match.zero + protected def zero: Tree = _match(vpmName.zero) + // __match.guard(`c`, `then`) + def guard(c: Tree, then: Tree): Tree = _match(vpmName.guard) APPLY (c, then) + + //// methods in the monad instance -- used directly in translation + // `prev`.flatMap(`b` => `next`) + def flatMap(prev: Tree, b: Symbol, next: Tree): Tree = (prev DOT vpmName.flatMap)(fun(b, next)) + // `thisCase`.orElse(`elseCase`) + def typedOrElse(thisCase: Tree, elseCase: Tree): Tree = (thisCase DOT vpmName.orElse) APPLY (elseCase) + // __match.guard(`cond`, `res`).flatMap(`nextBinder` => `next`) + def flatMapCond(cond: Tree, res: Tree, nextBinder: Symbol, next: Tree): Tree = flatMap(guard(cond, res), nextBinder, next) + // __match.guard(`guardTree`, ()).flatMap((_: P[Unit]) => `next`) + def flatMapGuard(guardTree: Tree, next: Tree): Tree = flatMapCond(guardTree, CODE.UNIT, freshSym(guardTree.pos, pureType(UnitClass.tpe)), next) + } + } + + +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +// OPTIMIZATIONS +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// + +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +// decisions, decisions +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// + + trait TreeMakerApproximation extends TreeMakers { self: CodegenCore => + object Test { + var currId = 0 + } + case class Test(cond: Cond, treeMaker: TreeMaker) { + // def <:<(other: Test) = cond <:< other.cond + // def andThen_: (prev: List[Test]): List[Test] = + // prev.filterNot(this <:< _) :+ this + + private val reusedBy = new collection.mutable.HashSet[Test] + var reuses: Option[Test] = None + def registerReuseBy(later: Test): Unit = { + assert(later.reuses.isEmpty, later.reuses) + reusedBy += later + later.reuses = Some(this) + } + + val id = { Test.currId += 1; Test.currId} + override def toString = + if (cond eq Top) "T" + else if(cond eq Havoc) "!?" + else "T"+ id + (if(reusedBy nonEmpty) "!["+ treeMaker +"]" else (if(reuses.isEmpty) "["+ treeMaker +"]" else " cf. T"+reuses.get.id)) + } + + object Cond { + // def refines(self: Cond, other: Cond): Boolean = (self, other) match { + // case (Bottom, _) => true + // case (Havoc , _) => true + // case (_ , Top) => true + // case (_ , _) => false + // } + var currId = 0 + } + + abstract class Cond { + // def testedPath: Tree + // def <:<(other: Cond) = Cond.refines(this, other) + + val id = { Cond.currId += 1; Cond.currId} + } + + // does not contribute any knowledge + case object Top extends Cond + + // takes away knowledge. e.g., a user-defined guard + case object Havoc extends Cond + + // we know everything! everything! + // this either means the case is unreachable, + // or that it is statically known to be picked -- at this point in the decision tree --> no point in emitting further alternatives + // case object Bottom extends Cond + + + object EqualityCond { + private val uniques = new collection.mutable.HashMap[(Tree, Tree), EqualityCond] + def apply(testedPath: Tree, rhs: Tree): EqualityCond = uniques getOrElseUpdate((testedPath, rhs), new EqualityCond(testedPath, rhs)) + } + class EqualityCond(testedPath: Tree, rhs: Tree) extends Cond { + // def negation = TopCond // inequality doesn't teach us anything + // do simplification when we know enough about the tree statically: + // - collapse equal trees + // - accumulate tests when (in)equality not known statically + // - become bottom when we statically know this can never match + + override def toString = testedPath +" == "+ rhs +"#"+ id + } + + object TypeCond { + private val uniques = new collection.mutable.HashMap[(Tree, Type), TypeCond] + def apply(testedPath: Tree, pt: Type): TypeCond = uniques getOrElseUpdate((testedPath, pt), new TypeCond(testedPath, pt)) + } + class TypeCond(testedPath: Tree, pt: Type) extends Cond { + // def negation = TopCond // inequality doesn't teach us anything + // do simplification when we know enough about the tree statically: + // - collapse equal trees + // - accumulate tests when (in)equality not known statically + // - become bottom when we statically know this can never match + override def toString = testedPath +" <: "+ pt +"#"+ id + } + + object TypeAndEqualityCond { + private val uniques = new collection.mutable.HashMap[(Tree, Type), TypeAndEqualityCond] + def apply(testedPath: Tree, pt: Type): TypeAndEqualityCond = uniques getOrElseUpdate((testedPath, pt), new TypeAndEqualityCond(testedPath, pt)) + } + class TypeAndEqualityCond(testedPath: Tree, pt: Type) extends Cond { + // def negation = TopCond // inequality doesn't teach us anything + // do simplification when we know enough about the tree statically: + // - collapse equal trees + // - accumulate tests when (in)equality not known statically + // - become bottom when we statically know this can never match + override def toString = testedPath +" (<: && ==) "+ pt +"#"+ id + } + + def approximateMatch(root: Symbol, cases: List[List[TreeMaker]]): List[List[Test]] = { + // a variable in this set should never be replaced by a tree that "does not consist of a selection on a variable in this set" (intuitively) + val pointsToBound = collection.mutable.HashSet(root) + + // the substitution that renames variables to variables in pointsToBound + var normalize: Substitution = EmptySubstitution + + // replaces a variable (in pointsToBound) by a selection on another variable in pointsToBound + // TODO check: + // pointsToBound -- accumSubst.from == Set(root) && (accumSubst.from.toSet -- pointsToBound) isEmpty + var accumSubst: Substitution = EmptySubstitution + + val trees = new collection.mutable.HashSet[Tree] + + def approximateTreeMaker(tm: TreeMaker): Test = { + val subst = tm.substitution + + // find part of substitution that replaces bound symbols by new symbols, and reverse that part + // so that we don't introduce new aliases for existing symbols, thus keeping the set of bound symbols minimal + val (boundSubst, unboundSubst) = (subst.from zip subst.to) partition {case (f, t) => + t.isInstanceOf[Ident] && (t.symbol ne NoSymbol) && pointsToBound(f) + } + val (boundFrom, boundTo) = boundSubst.unzip + normalize >>= Substitution(boundTo map (_.symbol), boundFrom map (CODE.REF(_))) + // println("normalize: "+ normalize) + + val (unboundFrom, unboundTo) = unboundSubst unzip + val okSubst = Substitution(unboundFrom, unboundTo map (normalize(_))) // it's important substitution does not duplicate trees here -- it helps to keep hash consing simple, anyway + pointsToBound ++= ((okSubst.from, okSubst.to).zipped filter { (f, t) => pointsToBound exists (sym => t.exists(_.symbol == sym)) })._1 + // println("pointsToBound: "+ pointsToBound) + + accumSubst >>= okSubst + // println("accumSubst: "+ accumSubst) + + // TODO: improve, e.g., for constants + def sameValue(a: Tree, b: Tree): Boolean = (a eq b) || ((a, b) match { + case (_ : Ident, _ : Ident) => a.symbol eq b.symbol + case _ => false + }) + + // hashconsing trees (modulo value-equality) + def unique(t: Tree): Tree = + trees find (a => a.equalsStructure0(t)(sameValue)) match { + case Some(orig) => orig // println("unique: "+ (t eq orig, orig)); + case _ => trees += t; t + } + + def uniqueTp(tp: Type): Type = tp match { + // typerefs etc are already hashconsed + case _ : UniqueType => tp + case tp@RefinedType(parents, EmptyScope) => tp.memo(tp: Type)(identity) // TODO: does this help? + case _ => tp + } + + def binderToUniqueTree(b: Symbol) = unique(accumSubst(normalize(CODE.REF(b)))) + + Test(tm match { + case ProductExtractorTreeMaker(pb, None, subst) => Top // TODO: NotNullTest(prevBinder) + case tm@TypeTestTreeMaker(prevBinder, nextBinderTp, _) => TypeCond(binderToUniqueTree(prevBinder), uniqueTp(nextBinderTp)) + case tm@TypeAndEqualityTestTreeMaker(_, patBinder, pt, _) => TypeAndEqualityCond(binderToUniqueTree(patBinder), uniqueTp(pt)) + case tm@EqualityTestTreeMaker(prevBinder, patTree, _) => EqualityCond(binderToUniqueTree(prevBinder), unique(patTree)) + case ExtractorTreeMaker(_, _, _, _) + | GuardTreeMaker(_) + | ProductExtractorTreeMaker(_, Some(_), _) => Havoc + case AlternativesTreeMaker(_, _, _) => Havoc // TODO: can do better here + case SubstOnlyTreeMaker(_, _) => Top + case BodyTreeMaker(_, _) => Havoc + }, tm) + } + + cases.map { _ map approximateTreeMaker } + } + } + +//// + trait CommonSubconditionElimination extends TreeMakerApproximation { self: OptimizedCodegen => + /** a flow-sensitive, generalised, common sub-expression elimination + * reuse knowledge from performed tests + * the only sub-expressions we consider are the conditions and results of the three tests (type, type&equality, equality) + * when a sub-expression is share, it is stored in a mutable variable + * the variable is floated up so that its scope includes all of the program that shares it + * we generalize sharing to implication, where b reuses a if a => b and priors(a) => priors(b) (the priors of a sub expression form the path through the decision tree) + * + * intended to be generalised to exhaustivity/reachability checking + */ + def doCSE(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type): List[List[TreeMaker]] = { + val testss = approximateMatch(prevBinder, cases) + + // interpret: + val dependencies = new collection.mutable.LinkedHashMap[Test, Set[Cond]] + val tested = new collection.mutable.HashSet[Cond] + testss foreach { tests => + tested.clear() + tests dropWhile { test => + val cond = test.cond + if ((cond eq Havoc) || (cond eq Top)) (cond eq Top) // stop when we encounter a havoc, skip top + else { + tested += cond + + // is there an earlier test that checks our condition and whose dependencies are implied by ours? + dependencies find { case (priorTest, deps) => + ((priorTest.cond eq cond) || (deps contains cond)) && (deps subsetOf tested) + } foreach { case (priorTest, deps) => + // if so, note the dependency in both tests + priorTest registerReuseBy test + } + + dependencies(test) = tested.toSet // copies + true + } + } + } + + // find longest prefix of tests that reuse a prior test, and whose dependent conditions monotonically increase + // then, collapse these contiguous sequences of reusing tests + // store the result of the final test and the intermediate results in hoisted mutable variables (TODO: optimize: don't store intermediate results that aren't used) + // replace each reference to a variable originally bound by a collapsed test by a reference to the hoisted variable + val reused = new collection.mutable.HashMap[TreeMaker, ReusedCondTreeMaker] + var okToCall = false + val reusedOrOrig = (tm: TreeMaker) => {assert(okToCall); reused.getOrElse(tm, tm)} + + val res = testss map { tests => + var currDeps = Set[Cond]() + val (sharedPrefix, suffix) = tests span { test => + (test.cond eq Top) || (for( + reusedTest <- test.reuses; + nextDeps <- dependencies.get(reusedTest); + diff <- (nextDeps -- currDeps).headOption; + _ <- Some(currDeps = nextDeps)) + yield diff).nonEmpty + } + + val collapsedTreeMakers = if (sharedPrefix.nonEmpty) { // even sharing prefixes of length 1 brings some benefit (overhead-percentage for compiler: 26->24%, lib: 19->16%) + for (test <- sharedPrefix; reusedTest <- test.reuses) reusedTest.treeMaker match { + case reusedCTM: CondTreeMaker => reused(reusedCTM) = ReusedCondTreeMaker(reusedCTM) + case _ => + } + + // println("sharedPrefix: "+ sharedPrefix) + for (lastShared <- sharedPrefix.reverse.dropWhile(_.cond eq Top).headOption; + lastReused <- lastShared.reuses) + yield ReusingCondTreeMaker(sharedPrefix, reusedOrOrig) :: suffix.map(_.treeMaker) + } else None + + collapsedTreeMakers getOrElse tests.map(_.treeMaker) // sharedPrefix need not be empty (but it only contains Top-tests, which are dropped above) + } + okToCall = true // TODO: remove (debugging) + + res mapConserve (_ mapConserve reusedOrOrig) + } + + object ReusedCondTreeMaker { + def apply(orig: CondTreeMaker) = new ReusedCondTreeMaker(orig.prevBinder, orig.nextBinder, orig.cond, orig.res, orig.pos) + } + class ReusedCondTreeMaker(prevBinder: Symbol, val nextBinder: Symbol, cond: Tree, res: Tree, pos: Position) extends TreeMaker { import CODE._ + lazy val localSubstitution = Substitution(List(prevBinder), List(CODE.REF(nextBinder))) + lazy val storedCond = freshSym(pos, BooleanClass.tpe, "rc") setFlag MUTABLE + lazy val treesToHoist: List[Tree] = { + nextBinder setFlag MUTABLE + List(storedCond, nextBinder) map { b => VAL(b) === codegen.mkZero(b.info) } + } + + // TODO: finer-grained duplication + def chainBefore(next: Tree)(casegen: Casegen): Tree = // assert(codegen eq optimizedCodegen) + atPos(pos)(casegen.asInstanceOf[optimizedCodegen.OptimizedCasegen].flatMapCondStored(cond, storedCond, res, nextBinder, substitution(next).duplicate)) + } + + case class ReusingCondTreeMaker(sharedPrefix: List[Test], toReused: TreeMaker => TreeMaker) extends TreeMaker { import CODE._ + lazy val dropped_priors = sharedPrefix map (t => (toReused(t.treeMaker), t.reuses map (test => toReused(test.treeMaker)))) + lazy val localSubstitution = { + val (from, to) = dropped_priors.collect { + case (dropped: CondTreeMaker, Some(prior: ReusedCondTreeMaker)) => + (dropped.nextBinder, REF(prior.nextBinder)) + }.unzip + val oldSubs = dropped_priors.collect { + case (dropped: TreeMaker, _) => + dropped.substitution + } + oldSubs.foldLeft(Substitution(from, to))(_ >> _) + } + + def chainBefore(next: Tree)(casegen: Casegen): Tree = { + val cond = REF(dropped_priors.reverse.collectFirst{case (_, Some(ctm: ReusedCondTreeMaker)) => ctm}.get.storedCond) + + // TODO: finer-grained duplication -- MUST duplicate though, or we'll get VerifyErrors since sharing trees confuses lambdalift, and its confusion it emits illegal casts (diagnosed by Grzegorz: checkcast T ; invokevirtual S.m, where T not a subtype of S) + casegen.ifThenElseZero(cond, substitution(next).duplicate) + } + } + } + + + //// DCE + trait DeadCodeElimination extends TreeMakers { self: CodegenCore => + // TODO: non-trivial dead-code elimination + // e.g., the following match should compile to a simple instanceof: + // case class Ident(name: String) + // for (Ident(name) <- ts) println(name) + def doDCE(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type): List[List[TreeMaker]] = { + // do minimal DCE + cases + } + } + + //// SWITCHES -- TODO: operate on Tests rather than TreeMakers + trait SwitchEmission extends TreeMakers with OptimizedMatchMonadInterface { self: CodegenCore => + abstract class SwitchMaker { + abstract class SwitchableTreeMakerExtractor { def unapply(x: TreeMaker): Option[Tree] } + val SwitchableTreeMaker: SwitchableTreeMakerExtractor + + def alternativesSupported: Boolean + + def isDefault(x: CaseDef): Boolean + def defaultSym: Symbol + def defaultBody: Tree + def defaultCase(scrutSym: Symbol = defaultSym, body: Tree = defaultBody): CaseDef + + private def sequence[T](xs: List[Option[T]]): Option[List[T]] = + if (xs exists (_.isEmpty)) None else Some(xs.flatten) + + // empty list ==> failure + def apply(cases: List[(Symbol, List[TreeMaker])], pt: Type): List[CaseDef] = { + val caseDefs = cases map { case (scrutSym, makers) => + makers match { + // default case + case (btm@BodyTreeMaker(body, _)) :: Nil => + Some(defaultCase(scrutSym, btm.substitution(body))) + // constant (or typetest for typeSwitch) + case SwitchableTreeMaker(pattern) :: (btm@BodyTreeMaker(body, _)) :: Nil => + Some(CaseDef(pattern, EmptyTree, btm.substitution(body))) + // alternatives + case AlternativesTreeMaker(_, altss, _) :: (btm@BodyTreeMaker(body, _)) :: Nil if alternativesSupported => + val casePatterns = altss map { + case SwitchableTreeMaker(pattern) :: Nil => + Some(pattern) + case _ => + None + } + + sequence(casePatterns) map { patterns => + val substedBody = btm.substitution(body) + CaseDef(Alternative(patterns), EmptyTree, substedBody) + } + case _ => //println("can't emit switch for "+ makers) + None //failure (can't translate pattern to a switch) + } + } + + (for( + caseDefs <- sequence(caseDefs)) yield + if (caseDefs exists isDefault) caseDefs + else { + caseDefs :+ defaultCase() + } + ) getOrElse Nil + } + } + + class RegularSwitchMaker(scrutSym: Symbol, matchFailGenOverride: Option[Tree => Tree]) extends SwitchMaker { + val switchableTpe = Set(ByteClass.tpe, ShortClass.tpe, IntClass.tpe, CharClass.tpe) + val alternativesSupported = true + + object SwitchablePattern { def unapply(pat: Tree): Option[Tree] = pat match { + case Literal(const@Constant((_: Byte ) | (_: Short) | (_: Int ) | (_: Char ))) => + Some(Literal(Constant(const.intValue))) // TODO: Java 7 allows strings in switches + case _ => None + }} + + object SwitchableTreeMaker extends SwitchableTreeMakerExtractor { + def unapply(x: TreeMaker): Option[Tree] = x match { + case EqualityTestTreeMaker(_, SwitchablePattern(const), _) => Some(const) + case _ => None + } + } + + def isDefault(x: CaseDef): Boolean = x match { + case CaseDef(Ident(nme.WILDCARD), EmptyTree, _) => true + case _ => false + } + + def defaultSym: Symbol = scrutSym + def defaultBody: Tree = { import CODE._; matchFailGenOverride map (gen => gen(REF(scrutSym))) getOrElse MATCHERROR(REF(scrutSym)) } + def defaultCase(scrutSym: Symbol = defaultSym, body: Tree = defaultBody): CaseDef = { import CODE._; atPos(body.pos) { + DEFAULT ==> body + }} + } + + override def emitSwitch(scrut: Tree, scrutSym: Symbol, cases: List[List[TreeMaker]], pt: Type, matchFailGenOverride: Option[Tree => Tree]): Option[Tree] = { import CODE._ + val regularSwitchMaker = new RegularSwitchMaker(scrutSym, matchFailGenOverride) + // TODO: if patterns allow switch but the type of the scrutinee doesn't, cast (type-test) the scrutinee to the corresponding switchable type and switch on the result + if (regularSwitchMaker.switchableTpe(scrutSym.tpe)) { + val caseDefsWithDefault = regularSwitchMaker(cases map {c => (scrutSym, c)}, pt) + if (caseDefsWithDefault.length <= 2) None // not worth emitting a switch... also, the optimizer has trouble digesting tiny switches, apparently, so let's be nice and not generate them + else { + // match on scrutSym -- converted to an int if necessary -- not on scrut directly (to avoid duplicating scrut) + val scrutToInt: Tree = + if (scrutSym.tpe =:= IntClass.tpe) REF(scrutSym) + else (REF(scrutSym) DOT (nme.toInt)) + Some(BLOCK( + VAL(scrutSym) === scrut, + Match(scrutToInt, caseDefsWithDefault) // a switch + )) + } + } else None + } + + // for the catch-cases in a try/catch + private object typeSwitchMaker extends SwitchMaker { + def switchableTpe(tp: Type) = true + val alternativesSupported = false // TODO: needs either back-end support of flattening of alternatives during typers + + // TODO: there are more treemaker-sequences that can be handled by type tests + // analyze the result of approximateTreeMaker rather than the TreeMaker itself + object SwitchableTreeMaker extends SwitchableTreeMakerExtractor { + def unapply(x: TreeMaker): Option[Tree] = x match { + case tm@TypeTestTreeMaker(_, _, _) => + Some(Bind(tm.nextBinder, Typed(Ident(nme.WILDCARD), TypeTree(tm.nextBinderTp)) /* not used by back-end */)) // -- TODO: use this if binder does not occur in the body + case tm@TypeAndEqualityTestTreeMaker(_, patBinder, pt, _) if tm.isStraightTypeTest => + Some(Bind(tm.nextBinder, Typed(Ident(nme.WILDCARD), TypeTree(tm.nextBinderTp)) /* not used by back-end */)) + case _ => + None + } + } + + def isDefault(x: CaseDef): Boolean = x match { + case CaseDef(Typed(Ident(nme.WILDCARD), tpt), EmptyTree, _) if (tpt.tpe =:= ThrowableClass.tpe) => true + case CaseDef(Bind(_, Typed(Ident(nme.WILDCARD), tpt)), EmptyTree, _) if (tpt.tpe =:= ThrowableClass.tpe) => true + case CaseDef(Ident(nme.WILDCARD), EmptyTree, _) => true + case _ => false + } + + lazy val defaultSym: Symbol = freshSym(NoPosition, ThrowableClass.tpe) + def defaultBody: Tree = Throw(CODE.REF(defaultSym)) + def defaultCase(scrutSym: Symbol = defaultSym, body: Tree = defaultBody): CaseDef = { import CODE._; atPos(body.pos) { + CASE (Bind(scrutSym, Typed(Ident(nme.WILDCARD), TypeTree(ThrowableClass.tpe)))) ==> body + }} + } + + // TODO: drop null checks + override def emitTypeSwitch(bindersAndCases: List[(Symbol, List[TreeMaker])], pt: Type): Option[List[CaseDef]] = { + val caseDefsWithDefault = typeSwitchMaker(bindersAndCases, pt) + if (caseDefsWithDefault isEmpty) None + else Some(caseDefsWithDefault) + } + } + + trait OptimizedMatchMonadInterface extends MatchMonadInterface { + override def inMatchMonad(tp: Type): Type = optionType(tp) + override def pureType(tp: Type): Type = tp + override protected def matchMonadSym = OptionClass + } + + trait OptimizedCodegen extends CodegenCore with TypedSubstitution with OptimizedMatchMonadInterface { + override def codegen: AbsCodegen = optimizedCodegen + + // trait AbsOptimizedCodegen extends AbsCodegen { + // def flatMapCondStored(cond: Tree, condSym: Symbol, res: Tree, nextBinder: Symbol, next: Tree): Tree + // } + // def optimizedCodegen: AbsOptimizedCodegen + + // when we know we're targetting Option, do some inlining the optimizer won't do + // for example, `o.flatMap(f)` becomes `if(o == None) None else f(o.get)`, similarly for orElse and guard + // this is a special instance of the advanced inlining optimization that takes a method call on + // an object of a type that only has two concrete subclasses, and inlines both bodies, guarded by an if to distinguish the two cases + object optimizedCodegen extends CommonCodegen { import CODE._ + + /** Inline runOrElse and get rid of Option allocations + * + * runOrElse(scrut: scrutTp)(matcher): resTp = matcher(scrut) getOrElse ${catchAll(`scrut`)} + * the matcher's optional result is encoded as a flag, keepGoing, where keepGoing == true encodes result.isEmpty, + * if keepGoing is false, the result Some(x) of the naive translation is encoded as matchRes == x + */ + def matcher(scrut: Tree, scrutSym: Symbol, restpe: Type)(cases: List[Casegen => Tree], matchFailGen: Option[Tree => Tree]): Tree = { + val matchEnd = NoSymbol.newLabel(freshName("matchEnd"), NoPosition) setFlag SYNTH_CASE + val matchRes = NoSymbol.newValueParameter(newTermName("x"), NoPosition, SYNTHETIC) setInfo restpe.withoutAnnotations // + matchEnd setInfo MethodType(List(matchRes), restpe) + + def newCaseSym = NoSymbol.newLabel(freshName("case"), NoPosition) setInfo MethodType(Nil, restpe) setFlag SYNTH_CASE + var nextCase = newCaseSym + def caseDef(mkCase: Casegen => Tree): Tree = { + val currCase = nextCase + nextCase = newCaseSym + val casegen = new OptimizedCasegen(matchEnd, nextCase, restpe) + LabelDef(currCase, Nil, mkCase(casegen)) + } + + def catchAll = matchFailGen map { matchFailGen => + val scrutRef = if(scrutSym ne NoSymbol) REF(scrutSym) else EmptyTree // for alternatives + // must jump to matchEnd, use result generated by matchFailGen (could be `FALSE` for isDefinedAt) + LabelDef(nextCase, Nil, matchEnd APPLY (matchFailGen(scrutRef))) + // don't cast the arg to matchEnd when using PartialFun synth in uncurry, since it won't detect the throw (see gen.withDefaultCase) + // the cast is necessary when using typedMatchAnonFun-style PartialFun synth: + // (_asInstanceOf(matchFailGen(scrutRef), restpe)) + } toList + // catchAll.isEmpty iff no synthetic default case needed (the (last) user-defined case is a default) + // if the last user-defined case is a default, it will never jump to the next case; it will go immediately to matchEnd + + // the generated block is taken apart in TailCalls under the following assumptions + // the assumption is once we encounter a case, the remainder of the block will consist of cases + // the prologue may be empty, usually it is the valdef that stores the scrut + // val (prologue, cases) = stats span (s => !s.isInstanceOf[LabelDef]) + + // scrutSym == NoSymbol when generating an alternatives matcher + val scrutDef = if(scrutSym ne NoSymbol) List(VAL(scrutSym) === scrut) else Nil // for alternatives + Block( + scrutDef ++ (cases map caseDef) ++ catchAll, + LabelDef(matchEnd, List(matchRes), REF(matchRes)) + ) + } + + class OptimizedCasegen(matchEnd: Symbol, nextCase: Symbol, restpe: Type) extends CommonCodegen with Casegen { + def matcher(scrut: Tree, scrutSym: Symbol, restpe: Type)(cases: List[Casegen => Tree], matchFailGen: Option[Tree => Tree]): Tree = + optimizedCodegen.matcher(scrut, scrutSym, restpe)(cases, matchFailGen) + + // only used to wrap the RHS of a body + // res: T + // returns MatchMonad[T] + def one(res: Tree): Tree = matchEnd APPLY (_asInstanceOf(res, restpe)) // need cast for GADT magic + protected def zero: Tree = nextCase APPLY () + + // prev: MatchMonad[T] + // b: T + // next: MatchMonad[U] + // returns MatchMonad[U] + def flatMap(prev: Tree, b: Symbol, next: Tree): Tree = { + val tp = inMatchMonad(b.tpe) + val prevSym = freshSym(prev.pos, tp, "o") + val isEmpty = tp member vpmName.isEmpty + val get = tp member vpmName.get + + BLOCK( + VAL(prevSym) === prev, + // must be isEmpty and get as we don't control the target of the call (prev is an extractor call) + ifThenElseZero(NOT(prevSym DOT isEmpty), Substitution(b, prevSym DOT get)(next)) + ) + } + + // cond: Boolean + // res: T + // nextBinder: T + // next == MatchMonad[U] + // returns MatchMonad[U] + def flatMapCond(cond: Tree, res: Tree, nextBinder: Symbol, next: Tree): Tree = + ifThenElseZero(cond, BLOCK( + VAL(nextBinder) === res, + next + )) + + // guardTree: Boolean + // next: MatchMonad[T] + // returns MatchMonad[T] + def flatMapGuard(guardTree: Tree, next: Tree): Tree = + ifThenElseZero(guardTree, next) + + def flatMapCondStored(cond: Tree, condSym: Symbol, res: Tree, nextBinder: Symbol, next: Tree): Tree = + ifThenElseZero(cond, BLOCK( + condSym === TRUE_typed, + nextBinder === res, + next + )) + } + + } + } + + + trait MatchOptimizations extends CommonSubconditionElimination + with DeadCodeElimination + with SwitchEmission + with OptimizedCodegen { self: TreeMakers => + override def optimizeCases(prevBinder: Symbol, cases: List[List[TreeMaker]], pt: Type): (List[List[TreeMaker]], List[Tree]) = { + val optCases = doCSE(prevBinder, doDCE(prevBinder, cases, pt), pt) + val toHoist = ( + for (treeMakers <- optCases) + yield treeMakers.collect{case tm: ReusedCondTreeMaker => tm.treesToHoist} + ).flatten.flatten.toList + (optCases, toHoist) + } + } +} diff --git a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala index 31d064c824..57e82ed706 100644 --- a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala +++ b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala @@ -299,6 +299,7 @@ trait SyntheticMethods extends ast.TreeDSL { newAcc resetFlag (ACCESSOR | PARAMACCESSOR) ddef.rhs.duplicate } + // TODO: shouldn't the next line be: `original resetFlag CASEACCESSOR`? ddef.symbol resetFlag CASEACCESSOR lb += logResult("case accessor new")(newAcc) } diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index 553cafe966..b827f2ac1a 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -26,12 +26,14 @@ import util.Statistics._ * @author Martin Odersky * @version 1.0 */ -trait Typers extends Modes with Adaptations with Taggings with PatMatVirtualiser { +trait Typers extends Modes with Adaptations with Taggings { self: Analyzer => import global._ import definitions._ + import patmat.DefaultOverrideMatchAttachment + final def forArgMode(fun: Tree, mode: Int) = if (treeInfo.isSelfOrSuperConstrCall(fun)) mode | SCCmode else mode @@ -83,8 +85,11 @@ trait Typers extends Modes with Adaptations with Taggings with PatMatVirtualiser private def isPastTyper = phase.id > currentRun.typerPhase.id - // don't translate matches in presentation compiler: it loses vital symbols that are needed to do hyperlinking - @inline private def doMatchTranslation = !forInteractive && opt.virtPatmat && (phase.id < currentRun.uncurryPhase.id) + // when true: + // - we may virtualize matches (if -Xexperimental and there's a suitable __match in scope) + // - we synthesize PartialFunction implementations for `x => x match {...}` and `match {...}` when the expected type is PartialFunction + // this is disabled by: -Xoldpatmat, scaladoc or interactive compilation + @inline private def newPatternMatching = opt.virtPatmat && !forScaladoc && !forInteractive // && (phase.id < currentRun.uncurryPhase.id) abstract class Typer(context0: Context) extends TyperDiagnostics with Adaptation with Tagging with TyperContextErrors { import context0.unit @@ -2226,19 +2231,43 @@ trait Typers extends Modes with Adaptations with Taggings with PatMatVirtualiser treeCopy.Match(tree, selector1, casesAdapted) setType resTp } - // match has been typed, now translate it - def translatedMatch(match_ : Match) = MatchTranslator(this).translateMatch(match_) + // match has been typed -- virtualize it if we're feeling experimental + // (virtualized matches are expanded during type checking so they have the full context available) + // otherwise, do nothing: matches are translated during phase `patmat` (unless -Xoldpatmat) + def virtualizedMatch(match_ : Match, mode: Int, pt: Type) = { + import patmat.{vpmName, PureMatchTranslator, OptimizingMatchTranslator} + + // TODO: add fallback __match sentinel to predef + val matchStrategy: Tree = + if (!(newPatternMatching && opt.experimental && context.isNameInScope(vpmName._match))) null // fast path, avoiding the next line if there's no __match to be seen + else newTyper(context.makeImplicit(reportAmbiguousErrors = false)).silent(_.typed(Ident(vpmName._match), EXPRmode, WildcardType), reportAmbiguousErrors = false) match { + case SilentResultValue(ms) => ms + case _ => null + } - // synthesize and type check a (Partial)Function implementation based on a match specified by `cases` - // Match(EmptyTree, cases) ==> new Function { def apply(params) = `translateMatch('`(param1,...,paramN)` match { cases }')` } + if (matchStrategy ne null) // virtualize + typed((new PureMatchTranslator(this.asInstanceOf[patmat.global.analyzer.Typer] /*TODO*/, matchStrategy)).translateMatch(match_), mode, pt) + else + match_ // will be translated in phase `patmat` + } + + // synthesize and type check a PartialFunction implementation based on a match specified by `cases` + // Match(EmptyTree, cases) ==> new PartialFunction { def apply(params) = `translateMatch('`(param1,...,paramN)` match { cases }')` } // for fresh params, the selector of the match we'll translated simply gathers those in a tuple + // NOTE: restricted to PartialFunction -- leave Function trees if the expected type does not demand a partial function class MatchFunTyper(tree: Tree, cases: List[CaseDef], mode: Int, pt0: Type) { + // TODO: remove FunctionN support -- this is currently designed so that it can emit FunctionN and PartialFunction subclasses + // however, we should leave Function nodes until Uncurry so phases after typer can still detect normal Function trees + // we need to synthesize PartialFunction impls, though, to avoid nastiness in Uncurry in transforming&duplicating generated pattern matcher trees + // TODO: remove PartialFunction support from UnCurry private val pt = deskolemizeGADTSkolems(pt0) private val targs = pt.normalize.typeArgs private val arity = if (isFunctionType(pt)) targs.length - 1 else 1 // TODO pt should always be a (Partial)Function, right? private val ptRes = if (targs.isEmpty) WildcardType else targs.last // may not be fully defined private val isPartial = pt.typeSymbol == PartialFunctionClass + assert(isPartial) + private val anonClass = context.owner.newAnonymousFunctionClass(tree.pos) private val funThis = This(anonClass) @@ -2291,7 +2320,7 @@ trait Typers extends Modes with Adaptations with Taggings with PatMatVirtualiser anonClass setInfo ClassInfoType(parents, newScope, anonClass) methodSym setInfoAndEnter MethodType(paramSyms, resTp) - DefDef(methodSym, methodBodyTyper.translatedMatch(match_)) + DefDef(methodSym, methodBodyTyper.virtualizedMatch(match_, mode, pt)) } } @@ -2330,7 +2359,7 @@ trait Typers extends Modes with Adaptations with Taggings with PatMatVirtualiser match_ setType B1.tpe // the default uses applyOrElse's first parameter since the scrut's type has been widened - val body = methodBodyTyper.translatedMatch(match_ withAttachment DefaultOverrideMatchAttachment(REF(default) APPLY (REF(x)))) + val body = methodBodyTyper.virtualizedMatch(match_ withAttachment DefaultOverrideMatchAttachment(REF(default) APPLY (REF(x))), mode, pt) DefDef(methodSym, body) } @@ -2348,13 +2377,13 @@ trait Typers extends Modes with Adaptations with Taggings with PatMatVirtualiser methodSym setInfoAndEnter MethodType(paramSyms, BooleanClass.tpe) val match_ = methodBodyTyper.typedMatch(selector, casesTrue, mode, BooleanClass.tpe) - val body = methodBodyTyper.translatedMatch(match_ withAttachment DefaultOverrideMatchAttachment(FALSE_typed)) + val body = methodBodyTyper.virtualizedMatch(match_ withAttachment DefaultOverrideMatchAttachment(FALSE_typed), mode, pt) DefDef(methodSym, body) } } - val members = if (isPartial) { + lazy val members = if (isPartial) { // somehow @cps annotations upset the typer when looking at applyOrElse's signature, but not apply's // TODO: figure out the details (T @cps[U] is not a subtype of Any, but then why does it work for the apply method?) if (targs forall (_ <:< AnyClass.tpe)) List(applyOrElseMethodDef, isDefinedAtMethod) @@ -2433,7 +2462,7 @@ trait Typers extends Modes with Adaptations with Taggings with PatMatVirtualiser fun.body match { // later phase indicates scaladoc is calling (where shit is messed up, I tell you) // -- so fall back to old patmat, which is more forgiving - case Match(sel, cases) if (sel ne EmptyTree) && doMatchTranslation => + case Match(sel, cases) if (sel ne EmptyTree) && newPatternMatching && (pt.typeSymbol == PartialFunctionClass) => // go to outer context -- must discard the context that was created for the Function since we're discarding the function // thus, its symbol, which serves as the current context.owner, is not the right owner // you won't know you're using the wrong owner until lambda lift crashes (unless you know better than to use the wrong owner) @@ -3823,11 +3852,13 @@ trait Typers extends Modes with Adaptations with Taggings with PatMatVirtualiser } } - def typedTranslatedMatch(tree: Tree, selector: Tree, cases: List[CaseDef]): Tree = + // under -Xexperimental (and not -Xoldpatmat), and when there's a suitable __match in scope, virtualize the pattern match + // otherwise, type the Match and leave it until phase `patmat` (immediately after typer) + // empty-selector matches are transformed into synthetic PartialFunction implementations when the expected type demands it + def typedVirtualizedMatch(tree: Tree, selector: Tree, cases: List[CaseDef]): Tree = if (selector == EmptyTree) { - if (doMatchTranslation) (new MatchFunTyper(tree, cases, mode, pt)).translated + if (newPatternMatching && (pt.typeSymbol == PartialFunctionClass)) (new MatchFunTyper(tree, cases, mode, pt)).translated else { - if (opt.virtPatmat) debugwarn("virtpatmat should not encounter empty-selector matches "+ tree) val arity = if (isFunctionType(pt)) pt.normalize.typeArgs.length - 1 else 1 val params = for (i <- List.range(0, arity)) yield atPos(tree.pos.focusStart) { @@ -3839,12 +3870,8 @@ trait Typers extends Modes with Adaptations with Taggings with PatMatVirtualiser val body = treeCopy.Match(tree, selector1, cases) typed1(atPos(tree.pos) { Function(params, body) }, mode, pt) } - } else { - if (!doMatchTranslation || (tree firstAttachment {case TranslatedMatchAttachment => } nonEmpty)) - typedMatch(selector, cases, mode, pt, tree) - else - typed(translatedMatch(typedMatch(selector, cases, mode, pt, tree)), mode, pt) - } + } else + virtualizedMatch(typedMatch(selector, cases, mode, pt, tree), mode, pt) def typedReturn(expr: Tree) = { val enclMethod = context.enclMethod @@ -4686,7 +4713,7 @@ trait Typers extends Modes with Adaptations with Taggings with PatMatVirtualiser typedIf(cond, thenp, elsep) case tree @ Match(selector, cases) => - typedTranslatedMatch(tree, selector, cases) + typedVirtualizedMatch(tree, selector, cases) case Return(expr) => typedReturn(expr) @@ -4702,9 +4729,6 @@ trait Typers extends Modes with Adaptations with Taggings with PatMatVirtualiser catches1 = catches1 map (adaptCase(_, mode, owntype)) } - if (doMatchTranslation) - catches1 = (MatchTranslator(this)).translateTry(catches1, owntype, tree.pos) - treeCopy.Try(tree, block1, catches1, finalizer1) setType owntype case Throw(expr) => diff --git a/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala b/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala index bed8e93d1b..862b19d0a4 100644 --- a/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala +++ b/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala @@ -3,8 +3,9 @@ package scala.tools.selectivecps import scala.tools.nsc.Global +import scala.tools.nsc.typechecker.Modes -abstract class CPSAnnotationChecker extends CPSUtils { +abstract class CPSAnnotationChecker extends CPSUtils with Modes { val global: Global import global._ import definitions._ @@ -177,59 +178,38 @@ abstract class CPSAnnotationChecker extends CPSUtils { override def adaptAnnotations(tree: Tree, mode: Int, pt: Type): Tree = { if (!cpsEnabled) return tree - vprintln("adapt annotations " + tree + " / " + tree.tpe + " / " + Integer.toHexString(mode) + " / " + pt) + vprintln("adapt annotations " + tree + " / " + tree.tpe + " / " + modeString(mode) + " / " + pt) - val annots1 = cpsParamAnnotation(tree.tpe) - val annots2 = cpsParamAnnotation(pt) + val patMode = (mode & global.analyzer.PATTERNmode) != 0 + val exprMode = (mode & global.analyzer.EXPRmode) != 0 + val byValMode = (mode & global.analyzer.BYVALmode) != 0 - if ((mode & global.analyzer.PATTERNmode) != 0) { - if (!annots1.isEmpty) { - return tree modifyType removeAllCPSAnnotations - } - } + val annotsTree = cpsParamAnnotation(tree.tpe) + val annotsExpected = cpsParamAnnotation(pt) -/* + // not sure I rephrased this comment correctly: + // replacing `patMode` in the condition below by `patMode || ((mode & global.analyzer.TYPEmode) != 0 && (mode & global.analyzer.BYVALmode))` // doesn't work correctly -- still relying on addAnnotations to remove things from ValDef symbols - if ((mode & global.analyzer.TYPEmode) != 0 && (mode & global.analyzer.BYVALmode) != 0) { - if (!annots1.isEmpty) { - println("removing annotation from " + tree + "/" + tree.tpe) - val s = tree.setType(removeAllCPSAnnotations(tree.tpe)) - println(s) - s - } - } -*/ - - if ((mode & global.analyzer.EXPRmode) != 0) { - if (annots1.isEmpty && !annots2.isEmpty && ((mode & global.analyzer.BYVALmode) == 0)) { // shiftUnit - // add a marker annotation that will make tree.tpe behave as pt, subtyping wise - // tree will look like having any possible annotation - //println("adapt annotations " + tree + " / " + tree.tpe + " / " + Integer.toHexString(mode) + " / " + pt) - //val same = annots2 forall { case AnnotationInfo(atp: TypeRef, _, _) => atp.typeArgs(0) =:= atp.typeArgs(1) } - // TBD: use same or not? see infer0.scala/infer1.scala - - // CAVEAT: - // for monomorphic answer types we want to have @plus @cps (for better checking) - // for answer type modification we want to have only @plus (because actual answer type may differ from pt) - - //val known = global.analyzer.isFullyDefined(pt) - - if (/*same &&*/ !hasPlusMarker(tree.tpe)) { - //if (known) - return tree modifyType (_ withAnnotations newPlusMarker() :: annots2) // needed for #1807 - //else - // return tree.setType(tree.tpe.withAnnotations(adapt::Nil)) - } - tree - } else if (!annots1.isEmpty && ((mode & global.analyzer.BYVALmode) != 0)) { // dropping annotation - // add a marker annotation that will make tree.tpe behave as pt, subtyping wise - // tree will look like having no annotation - if (!hasMinusMarker(tree.tpe)) { - return tree modifyType addMinusMarker - } - } - } - tree + if (patMode && !annotsTree.isEmpty) tree modifyType removeAllCPSAnnotations + else if (exprMode && !byValMode && !hasPlusMarker(tree.tpe) && annotsTree.isEmpty && annotsExpected.nonEmpty) { // shiftUnit + // add a marker annotation that will make tree.tpe behave as pt, subtyping wise + // tree will look like having any possible annotation + //println("adapt annotations " + tree + " / " + tree.tpe + " / " + Integer.toHexString(mode) + " / " + pt) + + // CAVEAT: + // for monomorphic answer types we want to have @plus @cps (for better checking) + // for answer type modification we want to have only @plus (because actual answer type may differ from pt) + + val res = tree modifyType (_ withAnnotations newPlusMarker() :: annotsExpected) // needed for #1807 + vprintln("adapted annotations (not by val) of " + tree + " to " + res.tpe) + res + } else if (exprMode && byValMode && !hasMinusMarker(tree.tpe) && annotsTree.nonEmpty) { // dropping annotation + // add a marker annotation that will make tree.tpe behave as pt, subtyping wise + // tree will look like having no annotation + val res = tree modifyType addMinusMarker + vprintln("adapted annotations (by val) of " + tree + " to " + res.tpe) + res + } else tree } def updateAttributesFromChildren(tpe: Type, childAnnots: List[AnnotationInfo], byName: List[Tree]): Type = { @@ -454,11 +434,10 @@ abstract class CPSAnnotationChecker extends CPSUtils { transChildrenInOrder(tree, tpe, List(cond), List(thenp, elsep)) case Match(select, cases) => - // TODO: can there be cases that are not CaseDefs?? check collect vs map! - transChildrenInOrder(tree, tpe, List(select), cases:::(cases collect { case CaseDef(_, _, body) => body })) + transChildrenInOrder(tree, tpe, List(select), cases:::(cases map { case CaseDef(_, _, body) => body })) case Try(block, catches, finalizer) => - val tpe1 = transChildrenInOrder(tree, tpe, Nil, block::catches:::(catches collect { case CaseDef(_, _, body) => body })) + val tpe1 = transChildrenInOrder(tree, tpe, Nil, block::catches:::(catches map { case CaseDef(_, _, body) => body })) val annots = cpsParamAnnotation(tpe1) if (annots.nonEmpty) { diff --git a/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala b/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala index e1d699debc..e9e9cf0fab 100644 --- a/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala +++ b/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala @@ -241,6 +241,8 @@ abstract class SelectiveANFTransform extends PluginComponent with Transform with // where D$idef = def L$i(..) = {L$i.body; L${i+1}(..)} case ldef @ LabelDef(name, params, rhs) => + // println("trans LABELDEF "+(name, params, tree.tpe, hasAnswerTypeAnn(tree.tpe))) + // TODO why does the labeldef's type have a cpsMinus annotation, whereas the rhs does not? (BYVALmode missing/too much somewhere?) if (hasAnswerTypeAnn(tree.tpe)) { // currentOwner.newMethod(name, tree.pos, Flags.SYNTHETIC) setInfo ldef.symbol.info val sym = ldef.symbol resetFlag Flags.LABEL @@ -456,10 +458,11 @@ abstract class SelectiveANFTransform extends PluginComponent with Transform with val (anfStats, anfExpr) = rec(stms, cpsA, List()) // println("\nanf-block:\n"+ ((stms :+ expr) mkString ("{", "\n", "}")) +"\nBECAME\n"+ ((anfStats :+ anfExpr) mkString ("{", "\n", "}"))) - + // println("synth case? "+ (anfStats map (t => (t, t.isDef, gen.hasSynthCaseSymbol(t))))) // SUPER UGLY HACK: handle virtpatmat-style matches, whose labels have already been turned into DefDefs if (anfStats.nonEmpty && (anfStats forall (t => !t.isDef || gen.hasSynthCaseSymbol(t)))) { val (prologue, rest) = (anfStats :+ anfExpr) span (s => !s.isInstanceOf[DefDef]) // find first case + // println("rest: "+ rest) // val (defs, calls) = rest partition (_.isInstanceOf[DefDef]) if (rest nonEmpty){ // the filter drops the ()'s emitted when transValue encountered a LabelDef diff --git a/src/continuations/plugin/scala/tools/selectivecps/SelectiveCPSTransform.scala b/src/continuations/plugin/scala/tools/selectivecps/SelectiveCPSTransform.scala index a78de8e6c8..dcb7cd601f 100644 --- a/src/continuations/plugin/scala/tools/selectivecps/SelectiveCPSTransform.scala +++ b/src/continuations/plugin/scala/tools/selectivecps/SelectiveCPSTransform.scala @@ -65,6 +65,7 @@ abstract class SelectiveCPSTransform extends PluginComponent with class CPSTransformer(unit: CompilationUnit) extends TypingTransformer(unit) { + private val patmatTransformer = patmat.newTransformer(unit) override def transform(tree: Tree): Tree = { if (!cpsEnabled) return tree @@ -212,7 +213,7 @@ abstract class SelectiveCPSTransform extends PluginComponent with val catch2 = localTyper.typedCases(List(catchIfDefined), ThrowableClass.tpe, targettp) //typedCases(tree, catches, ThrowableClass.tpe, pt) - localTyper.typed(Block(List(funDef), treeCopy.Try(tree, treeCopy.Block(block1, stms, expr2), catch2, finalizer1))) + patmatTransformer.transform(localTyper.typed(Block(List(funDef), treeCopy.Try(tree, treeCopy.Block(block1, stms, expr2), catch2, finalizer1)))) /* diff --git a/test/files/neg/gadts1.check b/test/files/neg/gadts1.check index 0441f604c9..44d2b114d6 100644 --- a/test/files/neg/gadts1.check +++ b/test/files/neg/gadts1.check @@ -11,7 +11,4 @@ gadts1.scala:20: error: type mismatch; required: a case Cell[a](x: Int) => c.x = 5 ^ -gadts1.scala:20: error: Could not typecheck extractor call: case class with arguments List((x @ (_: Int))) - case Cell[a](x: Int) => c.x = 5 - ^ -four errors found +three errors found diff --git a/test/files/neg/patmat-type-check.check b/test/files/neg/patmat-type-check.check index ab4451f089..e045841ce1 100644 --- a/test/files/neg/patmat-type-check.check +++ b/test/files/neg/patmat-type-check.check @@ -3,31 +3,19 @@ patmat-type-check.scala:22: error: scrutinee is incompatible with pattern type; required: String def f1 = "bob".reverse match { case Seq('b', 'o', 'b') => true } // fail ^ -patmat-type-check.scala:22: error: value _1 is not a member of object Seq - def f1 = "bob".reverse match { case Seq('b', 'o', 'b') => true } // fail - ^ patmat-type-check.scala:23: error: scrutinee is incompatible with pattern type; found : Seq[A] required: Array[Char] def f2 = "bob".toArray match { case Seq('b', 'o', 'b') => true } // fail ^ -patmat-type-check.scala:23: error: value _1 is not a member of object Seq - def f2 = "bob".toArray match { case Seq('b', 'o', 'b') => true } // fail - ^ patmat-type-check.scala:27: error: scrutinee is incompatible with pattern type; found : Seq[A] required: Test.Bop2 def f3(x: Bop2) = x match { case Seq('b', 'o', 'b') => true } // fail ^ -patmat-type-check.scala:27: error: value _1 is not a member of object Seq - def f3(x: Bop2) = x match { case Seq('b', 'o', 'b') => true } // fail - ^ patmat-type-check.scala:30: error: scrutinee is incompatible with pattern type; found : Seq[A] required: Test.Bop3[Char] def f4[T](x: Bop3[Char]) = x match { case Seq('b', 'o', 'b') => true } // fail ^ -patmat-type-check.scala:30: error: value _1 is not a member of object Seq - def f4[T](x: Bop3[Char]) = x match { case Seq('b', 'o', 'b') => true } // fail - ^ -8 errors found +four errors found diff --git a/test/files/neg/t0418.check b/test/files/neg/t0418.check index 50931a1bca..4e9ad2f9ae 100644 --- a/test/files/neg/t0418.check +++ b/test/files/neg/t0418.check @@ -4,7 +4,4 @@ t0418.scala:2: error: not found: value Foo12340771 t0418.scala:2: error: not found: value x null match { case Foo12340771.Bar(x) => x } ^ -t0418.scala:2: error: Could not typecheck extractor call: case class with arguments List((x @ _)) - null match { case Foo12340771.Bar(x) => x } - ^ -three errors found +two errors found diff --git a/test/files/neg/t112706A.check b/test/files/neg/t112706A.check index fb18b31be1..30d0c3ec91 100644 --- a/test/files/neg/t112706A.check +++ b/test/files/neg/t112706A.check @@ -3,7 +3,4 @@ t112706A.scala:5: error: constructor cannot be instantiated to expected type; required: String case Tuple2(node,_) => ^ -t112706A.scala:5: error: Could not typecheck extractor call: case class Tuple2 with arguments List((node @ _), _) - case Tuple2(node,_) => - ^ -two errors found +one error found diff --git a/test/files/neg/t3392.check b/test/files/neg/t3392.check index 3a39098c4e..842d63eec9 100644 --- a/test/files/neg/t3392.check +++ b/test/files/neg/t3392.check @@ -1,7 +1,4 @@ t3392.scala:9: error: not found: value x case x@A(x/*<-- refers to the pattern that includes this comment*/.Ex(42)) => ^ -t3392.scala:9: error: Could not typecheck extractor call: case class with arguments List(42) - case x@A(x/*<-- refers to the pattern that includes this comment*/.Ex(42)) => - ^ -two errors found +one error found diff --git a/test/files/neg/t418.check b/test/files/neg/t418.check index c06088ba9d..1489547823 100644 --- a/test/files/neg/t418.check +++ b/test/files/neg/t418.check @@ -4,7 +4,4 @@ t418.scala:2: error: not found: value Foo12340771 t418.scala:2: error: not found: value x null match { case Foo12340771.Bar(x) => x } ^ -t418.scala:2: error: Could not typecheck extractor call: case class with arguments List((x @ _)) - null match { case Foo12340771.Bar(x) => x } - ^ -three errors found +two errors found diff --git a/test/files/neg/t4515.check b/test/files/neg/t4515.check index 856d252a0f..a60d16295f 100644 --- a/test/files/neg/t4515.check +++ b/test/files/neg/t4515.check @@ -1,6 +1,6 @@ t4515.scala:37: error: type mismatch; - found : _0(in method apply) where type _0(in method apply) - required: (some other)_0(in method apply) + found : _0(in value $anonfun) where type _0(in value $anonfun) + required: (some other)_0(in value $anonfun) handler.onEvent(target, ctx.getEvent, node, ctx) ^ one error found diff --git a/test/files/neg/t5589neg.check b/test/files/neg/t5589neg.check index fb6858a397..b3ff16d7e4 100644 --- a/test/files/neg/t5589neg.check +++ b/test/files/neg/t5589neg.check @@ -22,9 +22,6 @@ t5589neg.scala:4: error: constructor cannot be instantiated to expected type; t5589neg.scala:4: error: not found: value y2 def f7(x: Either[Int, (String, Int)]) = for (y1 @ Tuple1(y2) <- x.right) yield ((y1, y2)) ^ -t5589neg.scala:4: error: Could not typecheck extractor call: case class Tuple1 with arguments List((y2 @ _)) - def f7(x: Either[Int, (String, Int)]) = for (y1 @ Tuple1(y2) <- x.right) yield ((y1, y2)) - ^ t5589neg.scala:5: error: constructor cannot be instantiated to expected type; found : (T1, T2, T3) required: (String, Int) @@ -37,4 +34,4 @@ t5589neg.scala:5: error: not found: value y2 def f8(x: Either[Int, (String, Int)]) = for ((y1, y2, y3) <- x.right) yield ((y1, y2)) ^ two warnings found -8 errors found +7 errors found diff --git a/test/files/run/inner-parse.check b/test/files/run/inner-parse.check index 87ea9ddeb5..e4a30714bd 100644 --- a/test/files/run/inner-parse.check +++ b/test/files/run/inner-parse.check @@ -5,6 +5,7 @@ class Test$$anonfun$main$1 extends scala.runtime.AbstractFunction1$mcVL$sp descriptor ()V descriptor apply (Lscala/Tuple2;)V descriptor apply (Ljava/lang/Object;)Ljava/lang/Object; + descriptor apply (Ljava/lang/Object;)V descriptor cwd$1 Ljava/lang/String; descriptor serialVersionUID J descriptor (Ljava/lang/String;)V diff --git a/test/files/run/programmatic-main.check b/test/files/run/programmatic-main.check index d16e2c5178..bdf76ddce1 100644 --- a/test/files/run/programmatic-main.check +++ b/test/files/run/programmatic-main.check @@ -4,27 +4,28 @@ namer 2 resolve names, attach symbols to named trees packageobjects 3 load package objects typer 4 the meat and potatoes: type the trees - superaccessors 5 add super accessors in traits and nested classes - extmethods 6 add extension methods for inline classes - pickler 7 serialize symbol tables - refchecks 8 reference/override checking, translate nested objects - uncurry 9 uncurry, translate function values to anonymous classes - tailcalls 10 replace tail calls by jumps - specialize 11 @specialized-driven class and method specialization - explicitouter 12 this refs to outer pointers, translate patterns - erasure 13 erase types, add interfaces for traits - posterasure 14 clean up erased inline classes - lazyvals 15 allocate bitmaps, translate lazy vals into lazified defs - lambdalift 16 move nested functions to top level - constructors 17 move field definitions into constructors - flatten 18 eliminate inner classes - mixin 19 mixin composition - cleanup 20 platform-specific cleanups, generate reflective calls - icode 21 generate portable intermediate code - inliner 22 optimization: do inlining -inlineExceptionHandlers 23 optimization: inline exception handlers - closelim 24 optimization: eliminate uncalled closures - dce 25 optimization: eliminate dead code - jvm 26 generate JVM bytecode - terminal 27 The last phase in the compiler chain + patmat 5 translate match expressions + superaccessors 6 add super accessors in traits and nested classes + extmethods 7 add extension methods for inline classes + pickler 8 serialize symbol tables + refchecks 9 reference/override checking, translate nested objects + uncurry 10 uncurry, translate function values to anonymous classes + tailcalls 11 replace tail calls by jumps + specialize 12 @specialized-driven class and method specialization + explicitouter 13 this refs to outer pointers, translate patterns + erasure 14 erase types, add interfaces for traits + posterasure 15 clean up erased inline classes + lazyvals 16 allocate bitmaps, translate lazy vals into lazified defs + lambdalift 17 move nested functions to top level + constructors 18 move field definitions into constructors + flatten 19 eliminate inner classes + mixin 20 mixin composition + cleanup 21 platform-specific cleanups, generate reflective calls + icode 22 generate portable intermediate code + inliner 23 optimization: do inlining +inlineExceptionHandlers 24 optimization: inline exception handlers + closelim 25 optimization: eliminate uncalled closures + dce 26 optimization: eliminate dead code + jvm 27 generate JVM bytecode + terminal 28 The last phase in the compiler chain diff --git a/test/files/run/virtpatmat_staging.flags b/test/files/run/virtpatmat_staging.flags index 3f5a3100e4..48fd867160 100644 --- a/test/files/run/virtpatmat_staging.flags +++ b/test/files/run/virtpatmat_staging.flags @@ -1 +1 @@ - -Xexperimental +-Xexperimental -- cgit v1.2.3