blob: d011956146e886e272cf372a7b8ce04a6ca11f55 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
|
package dotty.tools.dotc
package transform
import TreeTransforms._
import core.DenotTransformers._
import core.Symbols._
import core.Contexts._
import core.Types._
import core.Flags._
import core.Decorators._
import NonLocalReturns._
/** Lifts try's that might be executed on non-empty expression stacks
* to their own methods. I.e.
*
* try body catch handler
*
* is lifted to
*
* { def liftedTree$n() = try body catch handler; liftedTree$n() }
*/
class LiftTry extends MiniPhase with IdentityDenotTransformer { thisTransform =>
import ast.tpd._
/** the following two members override abstract members in Transform */
val phaseName: String = "liftTry"
val treeTransform = new Transform(needLift = false)
val liftingTransform = new Transform(needLift = true)
class Transform(needLift: Boolean) extends TreeTransform {
def phase = thisTransform
override def prepareForApply(tree: Apply)(implicit ctx: Context) =
if (tree.fun.symbol.is(Label)) this
else liftingTransform
override def prepareForValDef(tree: ValDef)(implicit ctx: Context) =
if (!tree.symbol.exists ||
tree.symbol.isSelfSym ||
tree.symbol.owner == ctx.owner.enclosingMethod) this
else liftingTransform
override def prepareForAssign(tree: Assign)(implicit ctx: Context) =
if (tree.lhs.symbol.maybeOwner == ctx.owner.enclosingMethod) this
else liftingTransform
override def prepareForReturn(tree: Return)(implicit ctx: Context) =
if (!isNonLocalReturn(tree)) this
else liftingTransform
override def prepareForTemplate(tree: Template)(implicit ctx: Context) =
treeTransform
override def transformTry(tree: Try)(implicit ctx: Context, info: TransformerInfo): Tree =
if (needLift) {
ctx.debuglog(i"lifting tree at ${tree.pos}, current owner = ${ctx.owner}")
val fn = ctx.newSymbol(
ctx.owner, ctx.freshName("liftedTree").toTermName, Synthetic | Method,
MethodType(Nil, tree.tpe.widenIfUnstable), coord = tree.pos)
tree.changeOwnerAfter(ctx.owner, fn, thisTransform)
Block(DefDef(fn, tree) :: Nil, ref(fn).appliedToNone)
}
else tree
}
}
|
