VladUreche

$ ls
A.scala B.scala

$ cat A.scala
class A[@specialized T](t: T)

$ scalac A.scala

$ cat B.scala
object Test extends App {

VladUreche

$ cat C.scala 
class C[@specialized T](t: T)
class D[@specialized T](t: T) extends C[T](t)

$ scalac C.scala 
C.scala:2: warning: class C must be a trait. Specialized version of class D will inherit generic C[Boolean]
class D[@specialized T](t: T) extends C[T](t)
      ^
one warning found

VladUreche

GSOC 2014 Challenge

####Fix the following bug miniboxing/miniboxing-plugin#63.

Short Explanation

In miniboxing, the optimized data representation stores values encoded on a long integer. Still, whenever the program needs to perform operations on the actual data, it is transformed to its original type.

For example, when doing the following operation:

VladUreche

$ cat infer.scala 
package p

class ann extends annotation.StaticAnnotation with annotation.TypeConstraint

class Seq[T] {
  def map[U](f: T => U): Seq[U] = ???
}

object Test {

VladUreche

$ cat test.scala
class Worker {
  def receive[Id: scala.reflect.ClassTag] =
    (x: Any) => x match {
      case source: Id =>
        val src: Id = source
    }
}

VladUreche

Bug: miniboxing/miniboxing-plugin#188

For the record, here's the full VM output (the flags I used there are only available in debug builds of the JVM, which, although they are also dead slow, make the same inlining decisions as the normal VM):

Full output

Miniboxed:

$ mb-scala -J-XX:+PrintCompilation -J-XX:+PrintInlining -J-XX:+TraceDeoptimization brique.Test
Picked up _JAVA_OPTIONS: -Xms2g -Xmx2g -Xss4m -XX:+CMSClassUnloadingEnabled -XX:MaxPermSize=512M -XX:ReservedCodeCacheSize=256m -XX:PermSize=256m -XX:+TieredCompilation -XX:+UseNUMA

VladUreche

Bug: miniboxing/miniboxing-plugin#188

Below are the full outputs. But let's take a typical loop in the generic code:

restarting timing
[GC 631036K->45244K(2043392K), 0.0217070 secs]
[GC 636604K->50652K(2049024K), 0.0495480 secs]
[GC 649692K->40220K(2045952K), 0.0023550 secs]
805 ms for 100 iterations

VladUreche

sun@sun-cpu:~/workspace/dev/test$ git clone https://github.com/miniboxing/miniboxing-plugin.git
Cloning into 'miniboxing-plugin'...
remote: Counting objects: 15469, done.
remote: Compressing objects: 100% (180/180), done.
remote: Total 15469 (delta 93), reused 0 (delta 0), pack-reused 15234
Receiving objects: 100% (15469/15469), 19.93 MiB | 2.43 MiB/s, done.
Resolving deltas: 100% (7734/7734), done.
Checking connectivity... done.
sun@sun-cpu:~/workspace/dev/test$ sbt miniboxing-plugin/coverage test coverageReport coverageAggregate

VladUreche

sun@sun-cpu:~/workspace/dev/test/miniboxing-plugin(wip)$ cat target/scala-2.11/coverage-report/cobertura.xml
<?xml version="1.0"?>
<!DOCTYPE coverage SYSTEM "http://cobertura.sourceforge.net/xml/coverage-04.dtd">
<coverage line-rate="0.87" lines-covered="5505" lines-valid="4789" branches-covered="451" branches-valid="388" branch-rate="0.86" complexity="0" version="1.0" timestamp="1431564530915">
      <sources>
        <source>/src/main/scala</source>
      </sources>
      <packages>
        <package name="miniboxing.plugin" line-rate="0.78" branch-rate="0.70" complexity="0">
      <classes>

VladUreche

Codecov v0.0.2 - Uploader
  url: https://codecov.io
  No CI detected, using git for branch and commit sha.
  Searching for coverage reports...  ok
  Detecting file structure...  ok
  Reading reports....ok
  query: package=bash-v0.0.2&branch=wip&commit=db72e704d5b258bf75904c9ea5722249fe571d37
https://codecov.io/upload/v2?package=bash-v0.0.2&branch=wip&commit=db72e704d5b258bf75904c9ea5722249fe571d37
.
./mb-scalac