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Micro-optimize Positions #3643

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Merged
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Dec 10, 2017
Merged

Micro-optimize Positions #3643

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19 changes: 7 additions & 12 deletions compiler/src/dotty/tools/dotc/util/Positions.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -11,12 +11,12 @@ import language.implicitConversions
*/
object Positions {

private val StartEndBits = 26
val StartEndMask: Long = (1L << StartEndBits) - 1
private val SyntheticPointDelta = (1 << (64 - StartEndBits * 2)) - 1
private final val StartEndBits = 26
private final val StartEndMask = (1L << StartEndBits) - 1
private final val SyntheticPointDelta = (1 << (64 - StartEndBits * 2)) - 1

/** The maximal representable offset in a position */
val MaxOffset = StartEndMask
private final val MaxOffset = StartEndMask

/** Convert offset `x` to an integer by sign extending the original
* field of `StartEndBits` width.
Expand Down Expand Up @@ -134,18 +134,13 @@ object Positions {
}

/** A synthetic position with given start and end */
def Position(start: Int, end: Int): Position = {
val pos = fromOffsets(start, end, SyntheticPointDelta)
assert(pos.isSynthetic)
pos
}
def Position(start: Int, end: Int): Position =
fromOffsets(start, end, SyntheticPointDelta)

/** A source-derived position with given start, end, and point delta */
def Position(start: Int, end: Int, point: Int): Position = {
val pointDelta = (point - start) max 0
val pos = fromOffsets(start, end, if (pointDelta >= SyntheticPointDelta) 0 else pointDelta)
assert(pos.isSourceDerived)
pos
fromOffsets(start, end, if (pointDelta >= SyntheticPointDelta) 0 else pointDelta)
}

/** A synthetic zero-extent position that starts and ends at given `start`. */
Expand Down