diff options
author | Adriaan Moors <adriaan.moors@epfl.ch> | 2012-06-28 03:53:06 -0700 |
---|---|---|
committer | Adriaan Moors <adriaan.moors@epfl.ch> | 2012-06-28 03:53:06 -0700 |
commit | df00b410635cd3164b74ab55d1b44fd772a65653 (patch) | |
tree | 9c5fa36022898eace09b431f3b05dfb1cc4545ea /src | |
parent | 2261452d18e955e16bbe43e7a21e8d79c44325e8 (diff) | |
parent | 1a3976fc8276e6e3d7eeda12f645782ca93ea24b (diff) | |
download | scala-df00b410635cd3164b74ab55d1b44fd772a65653.tar.gz scala-df00b410635cd3164b74ab55d1b44fd772a65653.tar.bz2 scala-df00b410635cd3164b74ab55d1b44fd772a65653.zip |
Merge pull request #783 from phaller/topic/cps-return-revert
Revert pull request #720 (CPS: enable return expressions in CPS code if ...
Diffstat (limited to 'src')
5 files changed, 3 insertions, 74 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Modes.scala b/src/compiler/scala/tools/nsc/typechecker/Modes.scala index bde3ad98c9..3eff5ef024 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Modes.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Modes.scala @@ -86,10 +86,6 @@ trait Modes { */ final val TYPEPATmode = 0x10000 - /** RETmode is set when we are typing a return expression. - */ - final val RETmode = 0x20000 - final private val StickyModes = EXPRmode | PATTERNmode | TYPEmode | ALTmode final def onlyStickyModes(mode: Int) = diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index 688c842637..d251109dc4 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -4024,8 +4024,7 @@ trait Typers extends Modes with Adaptations with Tags { ReturnWithoutTypeError(tree, enclMethod.owner) } else { context.enclMethod.returnsSeen = true - val expr1: Tree = typed(expr, EXPRmode | BYVALmode | RETmode, restpt.tpe) - + val expr1: Tree = typed(expr, EXPRmode | BYVALmode, restpt.tpe) // Warn about returning a value if no value can be returned. if (restpt.tpe.typeSymbol == UnitClass) { // The typing in expr1 says expr is Unit (it has already been coerced if diff --git a/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala b/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala index 464ffc6fab..a20ff1667b 100644 --- a/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala +++ b/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala @@ -171,9 +171,6 @@ abstract class CPSAnnotationChecker extends CPSUtils with Modes { vprintln("yes we can!! (byval)") return true } - } else if ((mode & global.analyzer.RETmode) != 0) { - vprintln("yes we can!! (return)") - return true } } false @@ -187,7 +184,6 @@ abstract class CPSAnnotationChecker extends CPSUtils with Modes { val patMode = (mode & global.analyzer.PATTERNmode) != 0 val exprMode = (mode & global.analyzer.EXPRmode) != 0 val byValMode = (mode & global.analyzer.BYVALmode) != 0 - val retMode = (mode & global.analyzer.RETmode) != 0 val annotsTree = cpsParamAnnotation(tree.tpe) val annotsExpected = cpsParamAnnotation(pt) @@ -214,12 +210,6 @@ abstract class CPSAnnotationChecker extends CPSUtils with Modes { val res = tree modifyType addMinusMarker vprintln("adapted annotations (by val) of " + tree + " to " + res.tpe) res - } else if (retMode && !hasPlusMarker(tree.tpe) && annotsTree.isEmpty && annotsExpected.nonEmpty) { - // 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 (_ withAnnotations List(newPlusMarker())) - vprintln("adapted annotations (return) of " + tree + " to " + res.tpe) - res } else tree } @@ -476,11 +466,6 @@ abstract class CPSAnnotationChecker extends CPSUtils with Modes { } tpe - case ret @ Return(expr) => - if (hasPlusMarker(expr.tpe)) - ret setType expr.tpe - ret.tpe - case _ => tpe } diff --git a/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala b/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala index 765cde5a81..3a1dc87a6a 100644 --- a/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala +++ b/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala @@ -3,7 +3,6 @@ package scala.tools.selectivecps import scala.tools.nsc.Global -import scala.collection.mutable.ListBuffer trait CPSUtils { val global: Global @@ -136,43 +135,4 @@ trait CPSUtils { case _ => None } } - - def isTailReturn(retExpr: Tree, body: Tree): Boolean = { - val removed = ListBuffer[Tree]() - removeTailReturn(body, removed) - removed contains retExpr - } - - def removeTailReturn(tree: Tree, removed: ListBuffer[Tree]): Tree = tree match { - case Block(stms, r @ Return(expr)) => - removed += r - treeCopy.Block(tree, stms, expr) - - case Block(stms, expr) => - treeCopy.Block(tree, stms, removeTailReturn(expr, removed)) - - case If(cond, r1 @ Return(thenExpr), r2 @ Return(elseExpr)) => - removed ++= Seq(r1, r2) - treeCopy.If(tree, cond, removeTailReturn(thenExpr, removed), removeTailReturn(elseExpr, removed)) - - case If(cond, thenExpr, elseExpr) => - treeCopy.If(tree, cond, removeTailReturn(thenExpr, removed), removeTailReturn(elseExpr, removed)) - - case Try(block, catches, finalizer) => - treeCopy.Try(tree, - removeTailReturn(block, removed), - (catches map (t => removeTailReturn(t, removed))).asInstanceOf[List[CaseDef]], - removeTailReturn(finalizer, removed)) - - case CaseDef(pat, guard, r @ Return(expr)) => - removed += r - treeCopy.CaseDef(tree, pat, guard, expr) - - case CaseDef(pat, guard, body) => - treeCopy.CaseDef(tree, pat, guard, removeTailReturn(body, removed)) - - case _ => - tree - } - } diff --git a/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala b/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala index fe465aad0d..017c8d24fd 100644 --- a/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala +++ b/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala @@ -9,8 +9,6 @@ import scala.tools.nsc.plugins._ import scala.tools.nsc.ast._ -import scala.collection.mutable.ListBuffer - /** * In methods marked @cps, explicitly name results of calls to other @cps methods */ @@ -48,20 +46,10 @@ abstract class SelectiveANFTransform extends PluginComponent with Transform with // this would cause infinite recursion. But we could remove the // ValDef case here. - case dd @ DefDef(mods, name, tparams, vparamss, tpt, rhs0) => + case dd @ DefDef(mods, name, tparams, vparamss, tpt, rhs) => debuglog("transforming " + dd.symbol) atOwner(dd.symbol) { - val tailReturns = ListBuffer[Tree]() - val rhs = removeTailReturn(rhs0, tailReturns) - // throw an error if there is a Return tree which is not in tail position - rhs0 foreach { - case r @ Return(_) => - if (!tailReturns.contains(r)) - unit.error(r.pos, "return expressions in CPS code must be in tail position") - case _ => /* do nothing */ - } - val rhs1 = transExpr(rhs, None, getExternalAnswerTypeAnn(tpt.tpe)) debuglog("result "+rhs1) @@ -165,6 +153,7 @@ abstract class SelectiveANFTransform extends PluginComponent with Transform with } } + def transExpr(tree: Tree, cpsA: CPSInfo, cpsR: CPSInfo): Tree = { transTailValue(tree, cpsA, cpsR) match { case (Nil, b) => b |