This change adds support for WASI in stdlib tests. Some tests that expect a crash to happen had to be disabled, since there's currently no way to observe such crash from a WASI host.
This replaces swiftMSVCRT with swiftCRT. The big difference here is
that the `visualc` module is no longer imported nor exported. The
`visualc` module remains in use for a singular test wrt availability,
but this should effectively remove the need for the `visualc` module.
The difference between the MSVCRT and ucrt module was not well
understood by most. MSVCRT provided ucrt AND visualc, combining pieces
of the old MSVCRT and the newer ucrt. The ucrt module is what you
really wanted most of the time, however, would need to use MSVCRT for
the convenience aliases for type-generic math and the deprecated math
constants.
Unfortunately, we cannot shadow the `ucrt` module and create a Swift SDK
overlay for ucrt as that seems to result in circular dependencies when
processing the `_Concurrency` module.
Although this makes using the C library easier for most people, it has a
more important subtle change: it cleaves the dependency on visualc.
This means that this enables use of Swift without Visual Studio for the
singular purpose of providing 3 header files. Additionally, it removes
the need for the installation of 2 of the 4 support files. This greatly
simplifies the deployment process on Windows.
Clean up a few general patterns that are now obviated by canImport
This aligns more generally with the cleanup that the Swift Package
Manager has already done in their automated XCTest-plumbing tool in
apple/swift-package-manager#1826.
This commit focuses the basics: setting up the relevant stanzas in
lit.cfg and adding platform conditionals for importing Glibc. Future
commits will deal with other portability fixes.
Different tests used different os checks for importing Darwin, Glibc and
MSVCRT. This commit use the same pattern for importing those libraries,
in order to avoid the #else branches of the incorrect patterns to be
applied to the wrong platform. This was very normal for Android, which
normally should follow the Linux branches, but sometimes was trying to
import Darwin or not importing anything.
The standarized pattern imports Darwin for macOS, iOS, tvOS and watchOS.
It imports Glibc for Linux, FreeBSD, PS4, Android, Cygwin and Haiku; and
imports MSVCRT for Windows. If a new platform is introduced, the else
branch will report an error, so the new platform can be added to one of
the branches (or maybe add a new specific branch).
In some cases the standard pattern was modified because some test required
it (importing extra modules, or extra type aliases), and in some other
cases some branches were removed because the test will not have used
them (but it is not exhaustive, so there might be some unnecessary
branches).
This should, at least, fix three tests for Android (the three
dynamic_replacement*.swift ones).
This adjusts the standard library test suite to mostly pass on Windows.
The remaining failures are due to various cases:
- memory corruption (`_swift_stdlib_free` in swiftDemangle)
- heap corruption (canGrowUsingRealloc)
- withVAList failure (unresolved)
- unicode handling on the command line
