CMake: Find Dispatch module #79455
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CMake: Find Dispatch module #79455
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etcwilde
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@compnerd, can I have you check that the filepaths work on Windows? I wasn't sure quite how to interpret the location from the xml files of the installer. |
edymtt
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etcwilde
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Feb 20, 2025
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etcwilde
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Feb 24, 2025
| dispatch_LIBRARY dispatch_INCLUDE_DIR) | ||
| elseif(WIN32) | ||
| # Issue: https://github.com/swiftlang/swift/issues/79591 | ||
| message(FATAL_ERROR "79591: Finddispatch.cmake module not implemented for Windows yet") |
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Okay, I think that should do it. Only have the implib and headers on Windows, sort of like the Apple SDKs.
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@swift-ci please smoke test |
Implementing an initial `Finddispatch.cmake` module to find Dispatch from the system SDK on Apple platforms. Still should implement a basic mechanism for finding it on Windows and Linux. Note that those platforms will likely use the dispatch config mechanism most frequently, but this should still work as a fallback. This mechanism is the only one that works for Apple platforms though as those use libdispatch from the SDK rather than building it with corelibs-libdispatch. When building for Linux and Windows, it is possible to build a custom corelibs-libdispatch runtime with `dispatch_DIR` and avoid this module. This module makes it possible to use a pre-built corelibs-libdispatch when one is available without needing to build it. The module uses the `Swift_SDKROOT` filepath as a hint on where to look for the runtime libraries and the `dispatch_STATIC` boolean to specify whether it should find the dynamic library or the static archive.
We need to define the defaulted setting so that it pulls in the default value. Otherwise we hit a configuration failure in `Concurrency/CMakeLists.txt` when it includes the config file specific to the global executor because `SwiftCore_CONCURRENCY_GLOBAL_EXECUTOR` is an empty string.
Enabling building the concurrency runtimes for build-testing purposes.
The dispatch global executor depends on finding dispatch. If dispatch is not found, it will fail to build. Mark it as required to get a configuration failure early.
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@swift-ci please smoke test |
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@swift-ci please smoke test Linux |
compnerd
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Feb 25, 2025
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Adding a
Finddispatch.cmakemodule to find libdispatch, both on Apple platforms and from corelibs-libdispatch.This gets concurrency building on Apple platforms, picking up Dispatch from the SDK.
When building for Windows and Linux, this module imports the library from the pre-existing SDK, making it possible to build Swift Concurrency without having to build dispatch if an existing copy is available.
If desired, one can set
dispatch_DIRto point at the directory containingdispatchConfig.cmakein order to pull in a new build, or set CMAKE_FIND_PACKAGE_PREFER_CONFIG to ignore the module entirely and search for an installed config file.When building for Apple-platforms, the module will only look for the libdispatch from the SDK.
When building for Linux, the module considers two variables:
swift_SDKROOT:FILEPATH: Path to the installed Swift SDK. The SDK and toolchain are currently shipped as one package, so this is likely just pointing at the root of the downloaded tarball.dispatch_STATIC:BOOLEAN: Hint the module to find the static archive for libdispatch instead of the dynamic library.