Swift and stdlib suitable for firmware / bare metal coding.

This repo is a fork of the apple/swift repo used for building swift-project1 and contains three main changes:

1. A -disable-red-zone compiler option to swiftc to compile code without using the red zone

2. A -mcode-model compiler option so that the kernel code model can be used.

3. Stdlib has been modified to remove:

• All floating point types (Float32/Float64) and code

• Math functions and some extra IO calls that are only needed for unix userland programs.

This allows stdlib to be compiled without using SSE registers or instructions to while still conforming to the x86_64 ABI.

The stdlib has also been compiled with -disable-red-zone, -mcode-model=kernel and -fno-omit-frame-pointer, -mno-omit-leaf-frame-pointer to enable easier stack backtraces.

A new branch is created each time the changes are rebased onto the latest swift upstream master so that the changes are kept at the top of the commits, and to make it easier to use an older version. The build script creates a tgz based on the date to maintain multiple versions.

This will probably have problems building on MacOS as Objective-C support will be compiled in which will only get in the way

NOTE: The master branch is just the swift master branch that it was rebased on.

The swift-kstdlib branch can be cloned from https://github.com/spevans/swift-kstdlib.git The other repos to clone are:

repo	branch
https://github.com/spevans/swift-kstdlib	latest kstdlib-YYYYMMDD
https://github.com/apple/swift-llvm	stable
https://github.com/apple/swift-clang	stable
https://github.com/apple/swift-compiler-rt	stable
https://github.com/apple/swift-cmark	master

git clone -b <kstdlib-YYYYMMDD> https://github.com/spevans/swift-kstdlib swift
git clone -b stable https://github.com/apple/swift-llvm llvm
git clone -b stable https://github.com/apple/swift-clang clang
git clone -b stable https://github.com/apple/swift-compiler-rt swift-compiler-rt
git clone https://github.com/apple/swift-cmark cmark
cd llvm/runtimes
ln -s ../../swift-compiler-rt compiler-rt
cd ../../swift
./utils/build-script  --no-swift-stdlib-assertions --build-subdir=buildbot_linux --release -- --swift-enable-ast-verifier=0 --install-swift --install-prefix=/usr '--swift-install-components=autolink-driver;compiler;clang-builtin-headers;stdlib' --build-swift-static-stdlib --skip-test-lldb --install-destdir=$HOME/swift-kernel --reconfigure  --verbose-build --jobs=2 2>&1|tee build.log

This will install a compiler and stdlib in ~/swift-kernel

Because of the code removed from Stdlib and compiling with the -mcode-model=kernel options , no tests can be run on the build and Foundation cannot be built either.

SDK overlays are also not built as these use OS provided functions that arent applicable or would need to be emulated.

When compiling .swift files, use the following arguments to disable red zone and SSE:

-Xfrontend -disable-red-zone -Xcc -mno-red-zone -Xcc -mno-mmx -Xcc -mno-sse -Xcc -mno-sse2

Then link with ~/swift-kernel/usr/lib/swift_static/linux/libswiftCore.a and ~/swift-kernel/usr/lib/swift/linux/x86_64/swiftrt.o.