If you forget to add a new file to the CMake configuration, you may end up with undefined symbol errors at link time.
There should be a CMakeLists.txt
in the directory where you added the new
file, which has the list of different .h/.cpp files to be included in the build.
Add your new file to that list.
The general idea is to build as little as you can.
- Use
sccache
orccache
if you aren't doing so already. - Use
build-script
's various--skip-*
flags to skip configuring for platforms that you do not care about. - If you're on macOS, use
--swift-darwin-supported-archs="x86_64"
. - Use a release build without assertions (
--release --no-assertions
). While debuginfo and assertions are valuable to enable when working on the toolchain itself, they are not so useful if you are working only on changes to the build system.
You can use the SWIFT_EXEC
environment variable to use a locally
built compiler to compile both packages and Xcode projects.
-
For SwiftPM packages, pass the environment variable when invoking SwiftPM.
# Assuming the current working directory contains the package, build the # package using a custom compiler. SWIFT_EXEC=/path/to/swiftc swift build
-
For Xcode projects, select the project in the Project Navigator. In the Build Settings tab, click '+' and then 'Add User-Defined Setting'. Create a build setting
SWIFT_EXEC
with the value set to/path/to/swiftc
. If you now do a clean build, your locally built compiler will be used.At the time of writing, in the latest Xcode 12.2 beta 3,
SWIFT_EXEC
does not work for SwiftPM integration inside Xcode, so this will not work for Xcode projects that depend on SwiftPM packages.
Note: Even thought the variable says 'SWIFT', it needs to point to 'swiftc', not 'swift'. The extra 'c' is not a typo.
TODO: Write some tips here, point to Testing.md for simulator setup.
This very depends on what X is, but some broad guidelines are:
- Do a case-insensitive recursive string search.
- Use a specialized tool like ripgrep or ag.
- Use
git grep --ignore-case "mypattern"
.git grep
also supports helpful flags which provide more context:--show-function
: Tries to print the function name that a match was found in.--function-context
: Tries to print the entire surrounding function containing the match.
- Use 'Find in Workspace' in Xcode (⌘+⇧+F).
- Use
grep --ignore-case --recursive "mypattern" .
.
- Go through the Documentation Index.
You can build the ReST formatted documentation as HTML using Sphinx. Follow
Sphinx's installation instructions and check that sphinx-build
is
available on your PATH
:
sphinx-build --version
If that succeeds, you can build the documentation using make
make -C docs
(Tested with sphinx-build
version 3.2.1.)
This compiles the .rst
files in the docs
directory into HTML in the
docs/_build/html
directory.
For the Markdown documentation, you can view the rendered HTML directly on GitHub. For example, this file is rendered on GitHub at https://github.com/apple/swift/tree/main/docs/HowToGuides/FAQ.md .
HTML documentation for the standard library on Darwin platforms is hosted on the Apple Developer website.
First, install clang-format
using your system's package manager. This should
also install the git-clang-format
script (try git-clang-format --help
).
In case it doesn't, you can replace git-clang-format
in the following
commands with ../llvm-project/clang/tools/clang-format/git-clang-format
.
Start out at the tip of the branch where you want to reformat the commits.
# If there is only one commit that needs to be reformatted.
git-clang-format HEAD~1
git add .
git commit --amend --no-edit
# Say the last N commits need to be reformatted.
# Mark them as 'edit' instead of 'pick'.
git rebase -i HEAD~N
# Re-run N times, reformatting each commit.
git-clang-format HEAD~1
git add .
git commit --amend --no-edit
git rebase --continue
TODO: Link to a beginner-friendly external resource, or (less preferably) describe basic usage of rebase here.