There's a longstanding problem in implementing `-isEqualToString:`,
where if you don't know how to get fast access to the other NSString's
contents, you have to pick between doing it character by character (very
slow), or calling [other isEqualToString: self], which risks infinite
recursion if the other string does the same.
This cuts the gordian knot by adding a new method
`isEqualToBytes:encoding:count:`, so you can get the contents out of
`self`, and hand it to the other string, confident that it will not need
to (nor, in fact be able to) ask you anything that might recurse.
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
rdar://172192966
The tasks of a task group were stored in a singly linked list, causing a
linear scan for a task to find its predecessor, whenever a task completed
and had to be removed from the list. This change turns it into a doubly
linked list, so the linear scan is avoided completely.
The inlinable certainly wont hurt on these "forwarding" methods, though
I was not able to confirm a noticable difference at least using this
benchmark.
Since adding those is definitely good anyway, I didn't dig much further,
let's just add them.
Assisted by: claude to make the benchmark, manually verified all changes
ran benchmarks and checked results etc
When built with output enabled, sometimes a few lines would be
interchanged, depending on the order in which parallel tasks
complete. Simplify the dispatcher logic a bit to ensure we get
the same output ordering every time.
This does not impact the running time of the benchmark.
This changes the implementation for `Collection.difference(from:)` to
use a linear-space complexity variation of the same Myers algorithm. The
new version is similar in execution time to the existing one, but should
alleviate memory pressure when diffing collections where the number of
differences approaches the size of the collection. While the new
algorithm returns a set of changes that is the same size as the previous
version, the specific changes are not guaranteed to be the same.
rdar://155829876
Enabling both of these despite the long runtime so that I can get an
accurate measure of the change with the new diffing implementation.
After #83212 is merged I will disable these large benchmarks again.
Fix warning in benchmark: generic parameter 'C' shadows generic parameter from outer scope with the same name; this is an error in the Swift 6 language mode
The SDK overlays have been provided in the Apple SDKs for many years, and the interface and implementation has diverged in more recent years such that trying to build the Swift version no longer works. Remove all of the dead code.
rdar://151889154
This is needed to unblock nightly toolchains, which are currently failing to build with an assertion:
```
swift-frontend: /home/build-user/build/buildbot_linux/llvm-linux-x86_64/tools/clang/include/clang/AST/TypeNodes.inc:79: TypeInfo clang::ASTContext::getTypeInfoImpl(const Type *) const: Assertion `!T->isDependentType() && "should not see dependent types here"' failed.
```
rdar://150067288
Slava Pestov
David Smith
Steven Wu
Konrad `ktoso` Malawski
Owen Voorhees
Dario Rexin
Meghana Gupta
Meghana Gupta
Karoy Lorentey
eeckstein
Rick van Voorden
Xiaodi Wu
Aidan Hall
Nate Cook
Valeriy Van
Gabor Horvath
Stephen Canon
Ian Anderson
John Hui
Egor Zhdan