When testing different linkers, it's sometimes useful to run the tests
with `SWIFT_DRIVER_TEST_OPTIONS=" -use-ld=<linker>"`. If we do this,
it will break a handful of tests because they expect the compiler driver
to choose an appropriate linker automatically.
To avoid having these fail, detect when someone has done this, and
set a new feature, `linker_overridden`, then mark the tests in question
with `UNSUPPORTED: linker_overridden`.
rdar://123504095
This change introduces a new compilation target platform to the Swift compiler - visionOS.
- Changes to the compiler build infrastrucuture to support building compiler-adjacent artifacts and test suites for the new target.
- Addition of the new platform kind definition.
- Support for the new platform in language constructs such as compile-time availability annotations or runtime OS version queries.
- Utilities to read out Darwin platform SDK info containing platform mapping data.
- Utilities to support re-mapping availability annotations from iOS to visionOS (e.g. 'updateIntroducedPlatformForFallback', 'updateDeprecatedPlatformForFallback', 'updateObsoletedPlatformForFallback').
- Additional tests exercising platform-specific availability handling and availability re-mapping fallback code-path.
- Changes to existing test suite to accomodate the new platform.
Also, make the analogous change to apple/swift-driver#1372, which gets the
sanitizer tests working on Android again, and remove the lld_lto feature in the
tests, which is now unused.
With Gold from the Android NDK setting up LTO is complicated, and the CI
machines are not setup for it.
Disable this test in platforms that do not use LLD and LTO (which is
basically Android with older NDKs).
This commit adds LTO support for handling linker options and LLVM BC
emission. Even for ELF, swift-autolink-extract is unnecessary because
linker options are embeded in LLVM BC content when LTO.
