Add a new --enable-caching option that enables compilation caching for both
C/C++ (via clang-cache as compiler launcher) and Swift code (via
-cache-compile-job flags when bootstrapping=hosttools).
New options:
- --enable-caching: main toggle, incompatible with --sccache/--distcc
- --caching-cas-path: CAS directory (default: $BUILD_ROOT/cas)
- --caching-depscan-socket: depscan daemon socket path
- --caching-plugin-path: CAS plugin library path
- --caching-plugin-option: CAS plugin options (repeatable)
- --caching-prefix-map: enable source/SDK/toolchain prefix mapping
- --caching-remote-service-path: remote caching service with auto
plugin inference from Xcode and implied prefix mapping
The build script starts a clang-cache depscan daemon with reliable cleanup
via atexit and SIGTERM handlers. Per-product build directories get .cas-config
and compilation-prefix-map.json files written automatically.
Caching flags are applied to all Swift host compilation targets: compiler
sources, pure-swift host libraries (ASTGen, macros), swift-syntax, and
the new runtime build when --build-runtime-with-host-compiler is used.
When not using --caching-remote-service-path, enables CAS backend
(-Xfrontend -cas-backend -Xllvm -cas-friendly-debug-info) unless
SWIFT_CACHE_DISABLE_MCCAS is set.
A ninja wrapper is generated at build/<subdir>/build-utils/ninja for
cached incremental builds outside the build-script.
rdar://155876033
Assisted-By: Claude
Build 'lib/swift/host' libraries and linking binaries as a single
"package" instead of buillding the linking binaries with
"prefer-interface" hack.
This enables CMO between them.
Add cross-compilation flags for the newly added Swift source in `lib/ASTGen/`,
similar to how `SwiftCompilerSources/` is already cross-compiled for other
platforms. Make sure the Swift source in the compiler builds and links against
`SWIFTLIB_DIR` in this cross-compilation build directory, not the one that comes
with the native host compiler.
This requires changing the dependency chain in `CROSSCOMPILE` mode, as normally
the Swift compiler is built first when building natively for the host, then it's
used to build the stdlib. However, when cross-compiling the toolchain, the stdlib
must be cross-compiled first by the host compiler, then the portions of the
Swift compiler written in Swift must be cross-compiled with that new stdlib. All
these dependency changes simply change that compilation order when cross-compiling,
including removing the dependency that the Swift compiler is built before the
stdlib when cross-compiling the Swift compiler.
All changes in this pull are gated on the `CROSSCOMPILE` mode, so they will
not affect any of the existing CI or build presets.
Previously, swift-syntax libraries were built in '/CMakeLists.txt', and
were installed in '/lib/CMakeLists.txt'. Consolidate them into
'/lib/SwiftSyntax/CMakeLists.txt'. Now the swift-syntax libraries look
like any other tool libraries outside the 'lib/SwiftSyntax', as they
should.
Steven Wu
Artem Chikin
Rintaro Ishizaki
Doug Gregor
eeckstein
Alex Hoppen
Finagolfin