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Jason Zaugg
3c508ce52d
The compiler interface subclasses `scala.tools.nsc.Global`, and loading this new subclass before each `compile` task forces HotSpot JIT to deoptimize larges swathes of compiled code. It's a bit like SBT has rigged the dice to always descend the longest ladder in a game of Snakes and Ladders. The slowdown seems to be larger with Scala 2.12. There are a number of variables at play, but I think the main factor here is that we now rely on JIT to devirtualize calls to final methods in traits whereas we used to emit static calls. JIT does a good job at this, so long as classloading doesn't undo that good work. This commit extends the existing `ClassLoaderCache` to encompass the classloader that includes the compiler interface JAR. I've resorted to adding a var to `AnalyzingCompiler` to inject the dependency to get the cache to the spot I need it without binary incompatible changes to the intervening method signatures.
sbt
sbt is a build tool for Scala, Java, and more.
For general documentation, see http://www.scala-sbt.org/.
sbt 1.0.x
This is the 1.0.x series of sbt. The source code of sbt is split across several Github repositories, including this one.
- sbt/io hosts
sbt.iomodule. - sbt/util hosts a collection of internally used modules.
- sbt/librarymanagement hosts
sbt.librarymanagementmodule that wraps Ivy. - sbt/zinc hosts Zinc, an incremental compiler for Scala.
- sbt/sbt, this repository hosts modules that implements the build tool.
Other links
- Setup: Describes getting started with the latest binary release.
- FAQ: Explains how to get help and more.
- sbt/sbt-zero-seven: hosts sbt 0.7.7 and earlier versions
Issues and Pull Requests
Please read CONTRIBUTING carefully before opening a GitHub Issue.
The short version: try searching or asking on StackOverflow and sbt-dev.
license
See LICENSE.