# Docker images for CI

This folder contains a bunch of docker images used by the continuous integration
(CI) of Rust. An script is accompanied (`run.sh`) with these images to actually
execute them. To test out an image execute:

```
./src/ci/docker/run.sh $image_name
```

for example:

```
./src/ci/docker/run.sh x86_64-gnu
```

Images will output artifacts in an `obj` dir at the root of a repository.

## Cross toolchains

A number of these images take quite a long time to compile as they're building
whole gcc toolchains to do cross builds with. Much of this is relatively
self-explanatory but some images use [crosstool-ng] which isn't quite as self
explanatory. Below is a description of where these `*.config` files come form,
how to generate them, and how the existing ones were generated.

[crosstool-ng]: https://github.com/crosstool-ng/crosstool-ng

### Generating a `.config` file

If you have a `linux-cross` image lying around you can use that and skip the
next two steps.

- First we spin up a container and copy `build_toolchain_root.sh` into it. All
  these steps are outside the container:

```
# Note: We use ubuntu:15.10 because that's the "base" of linux-cross Docker
# image
$ docker run -it ubuntu:15.10 bash
$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
cfbec05ed730        ubuntu:15.10        "bash"              16 seconds ago      Up 15 seconds                           drunk_murdock
$ docker cp build_toolchain_root.sh drunk_murdock:/
```

- Then inside the container we build crosstool-ng by simply calling the bash
  script we copied in the previous step:

```
$ bash build_toolchain_root.sh
```

- Now, inside the container run the following command to configure the
  toolchain. To get a clue of which options need to be changed check the next
  section and come back.

```
$ ct-ng menuconfig
```

- Finally, we retrieve the `.config` file from the container and give it a
  meaningful name. This is done outside the container.

```
$ docker drunk_murdock:/.config arm-linux-gnueabi.config
```

- Now you can shutdown the container or repeat the two last steps to generate a
  new `.config` file.

### Toolchain configuration

Changes on top of the default toolchain configuration used to generate the
`.config` files in this directory. The changes are formatted as follows:

```
$category > $option = $value -- $comment
```

### `arm-linux-gnueabi.config`

For targets: `arm-unknown-linux-gnueabi`

- Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
- Target options > Target Architecture = arm
- Target options > Architecture level = armv6 -- (+)
- Target options > Floating point = software (no FPU) -- (\*)
- Operating System > Target OS = linux
- Operating System > Linux kernel version = 3.2.72 -- Precise kernel
- C-library > glibc version = 2.14.1
- C compiler > gcc version = 4.9.3
- C compiler > C++ = ENABLE -- to cross compile LLVM

### `arm-linux-gnueabihf.config`

For targets: `arm-unknown-linux-gnueabihf`

- Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
- Target options > Target Architecture = arm
- Target options > Architecture level = armv6 -- (+)
- Target options > Use specific FPU = vfp -- (+)
- Target options > Floating point = hardware (FPU) -- (\*)
- Target options > Default instruction set mode = arm -- (+)
- Operating System > Target OS = linux
- Operating System > Linux kernel version = 3.2.72 -- Precise kernel
- C-library > glibc version = 2.14.1
- C compiler > gcc version = 4.9.3
- C compiler > C++ = ENABLE -- to cross compile LLVM

### `armv7-linux-gnueabihf.config`

For targets: `armv7-unknown-linux-gnueabihf`

- Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
- Target options > Target Architecture = arm
- Target options > Suffix to the arch-part = v7
- Target options > Architecture level = armv7-a -- (+)
- Target options > Use specific FPU = vfpv3-d16 -- (\*)
- Target options > Floating point = hardware (FPU) -- (\*)
- Target options > Default instruction set mode = thumb -- (\*)
- Operating System > Target OS = linux
- Operating System > Linux kernel version = 3.2.72 -- Precise kernel
- C-library > glibc version = 2.14.1
- C compiler > gcc version = 4.9.3
- C compiler > C++ = ENABLE -- to cross compile LLVM

(\*) These options have been selected to match the configuration of the arm
      toolchains shipped with Ubuntu 15.10
(+) These options have been selected to match the gcc flags we use to compile C
    libraries like jemalloc. See the mk/cfg/arm(v7)-uknown-linux-gnueabi{,hf}.mk
    file in Rust's source code.

## `aarch64-linux-gnu.config`

For targets: `aarch64-unknown-linux-gnu`

- Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
- Target options > Target Architecture = arm
- Target options > Bitness = 64-bit
- Operating System > Target OS = linux
- Operating System > Linux kernel version = 4.2.6
- C-library > glibc version = 2.17 -- aarch64 support was introduced in this version
- C compiler > gcc version = 5.2.0
- C compiler > C++ = ENABLE -- to cross compile LLVM

## `powerpc-linux-gnu.config`

For targets: `powerpc-unknown-linux-gnu`

- Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
- Path and misc options > Patches origin = Bundled, then local
- Path and misc options > Local patch directory = /tmp/patches
- Target options > Target Architecture = powerpc
- Target options > Emit assembly for CPU = power4 -- (+)
- Target options > Tune for CPU = power6 -- (+)
- Operating System > Target OS = linux
- Operating System > Linux kernel version = 2.6.32.68 -- ~RHEL6 kernel
- C-library > glibc version = 2.12.2 -- ~RHEL6 glibc
- C compiler > gcc version = 4.9.3
- C compiler > Core gcc extra config = --with-cpu-32=power4 --with-cpu=default32 -- (+)
- C compiler > gcc extra config = --with-cpu-32=power4 --with-cpu=default32 -- (+)
- C compiler > C++ = ENABLE -- to cross compile LLVM

(+) These CPU options match the configuration of the toolchains in RHEL6.

## `powerpc64-linux-gnu.config`

For targets: `powerpc64-unknown-linux-gnu`

- Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
- Path and misc options > Patches origin = Bundled, then local
- Path and misc options > Local patch directory = /tmp/patches
- Target options > Target Architecture = powerpc
- Target options > Bitness = 64-bit
- Target options > Emit assembly for CPU = power4 -- (+)
- Target options > Tune for CPU = power6 -- (+)
- Operating System > Target OS = linux
- Operating System > Linux kernel version = 2.6.32.68 -- ~RHEL6 kernel
- C-library > glibc version = 2.12.2 -- ~RHEL6 glibc
- C compiler > gcc version = 4.9.3
- C compiler > C++ = ENABLE -- to cross compile LLVM

(+) These CPU options match the configuration of the toolchains in RHEL6.

## `s390x-linux-gnu.config`

For targets: `s390x-unknown-linux-gnu`

- Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
- Path and misc options > Patches origin = Bundled, then local
- Path and misc options > Local patch directory = /build/patches
- Target options > Target Architecture = s390
- Target options > Bitness = 64-bit
- Operating System > Target OS = linux
- Operating System > Linux kernel version = 2.6.32.68 -- ~RHEL6 kernel
- C-library > glibc version = 2.12.2 -- ~RHEL6 glibc
- C compiler > gcc version = 4.9.3
- C compiler > gcc extra config = --with-arch=z10 -- LLVM's minimum support
- C compiler > C++ = ENABLE -- to cross compile LLVM
