Local Scala Native

This is a fork of the Scala Native compiler (links below) that implements variable sized stack-allocated values on a shadow stack as described in "What If We Don’t Pop the Stack? The Return of 2nd-Class Values".

Directory structure

The localplugin directory contains the type plugin implementing the type system.

Code generation required changes mainly in

• nscplugin: scalac phase implementing the Scala Native frontend that generates NIR files
• nativelib: GC code
• nir: native ir data structures. Added localalloc node + updates arrayalloc to include whether array is local

The sandbox directory contains example code and benchmarks.

The coq directory contains the mechanization of the theorems in Coq.

Running the benchmarks

Building the image (option 1)

The project provides a ImageDockerfile to reproduce the development and evaluation environment.

To build the image run

make image

The command above will create an image called local-scala-native. You can check this by running docker images.

Loading the available image (option 2)

Alternatively, if a pre-built image of this project was downloaded, it is possible to import it as follows.

docker load -i local-scala-native.tar.gz

Run commands

To run the benchmarks, first run the container interactively.

docker run --name ecoop_container --rm -it local-scala-native bash

Then, in the container shell just started run

./run.sh

This will produce two files under the tables directory:

• tables/runtime.csv corresponds to the table in Fig. 14
• tables/gc_stats.csv corresponds to Table 1

To modify and explore the repository inside the container we suggest to use Visual Studio Code with the Remote - Containers extension (also described here).

It is possible to copy files from the container to host through the docker cp command

docker cp ecoop_container:/home/local-scala-native/tables/gc_stats.csv .

Storage mode walk-through

The sandbox directory/project contains the code of the benchmarks and additionally a walk-through on storage modes (Examples.scala).

There are two main entries, one in Benchmarks.scala and one in Examples.scala. Benchmarks.scala is the default main entry and it is possible to recompile it with the following command.

sbt sandbox/nativeLink

This produces the binary sandbox/target/scala-2.12/sandbox-out. The sandbox/target/scala-2.12/native directory contains the native ir and llvm ir representations of the code.

To compile and run the code to use the main method in Examples.scala run the following command.

sbt run-examples

This will produce a new binary at the same path with main entry the one in Examples.scala.

If a mis-compilation arises due to a sequence of commands it is possible to clean the artifacts with

sbt sandbox/clean

Cleanup

To delete the image, ensure that the container is not running by closing the interactive session and then run.

docker rmi local-scala-native