This patch adds support for tracking the swiftmodules for executables
exporting symbols.
This fixes a bug in the earlier implementation around emitting the
swiftmodule. Previously, the code would use
`CMAKE_EXE_EXPORTS_Swift_FLAG` to inject the `-emit-module`, and module
path information into the `CMAKE_Swift_LINK_EXECUTABLE` rule. Because
Swift skips the build step and only runs during the link phase, these
flags were injected in `cmNinjaNormalTargetGenerator::ComputeLinkCmd`
instead of `cmLocalGenerator::GetTargetFlags` where it is done normally.
Unfortunately, injecting in `ComputeLinkCmd` didn't do anything because
we have a `linkCmd` so `ComputeLinkCmd` exits early, before the
EXE_EXPORT flags get added to the link command.
Instead of playing with that flag, CMake checks
`CMAKE_Swift_LINK_EXECUTABLE_WITH_EXPORTS` and uses that as the link
rule if it exists and falls back on `CMAKE_Swift_LINK_EXECUTABLE`. I've
defined that variable in terms of `CMAKE_Swift_LINK_EXECUTABLE` with the
necessary additional flags for emitting the swift module instead. This
has the same end effect as the desired behavior, but simplifies things a
bit.
Since we're generating the swiftmodule for executables with exports,
I've also updated the dependency graph to include the swiftmodule as an
output in the build dependency graph if the executable has exports.
Tests updated:
- RunCMake/NoWorkToDo:
Ensure that the build graph does not result in unnecessary rebuilds
with exporting executables.
- SwiftOnly:
Ensure that we can consume functions defined in the executable by a
library getting linked into said executable.
correct Xcode generator Swift definitions
original code was defining GCC_PREPROCESSOR_DEFINITIONS which is valid only for C languages
add definitions to SWIFT_ACTIVE_COMPILATION_CONDITIONS when Swift language is used in the target
add test in SwiftOnly
for old Xcode (<8.0), append defines to cflags so it ends up in OTHER_SWIFT_FLAGS
Fixes: #23637
Extend the `SwiftOnly` test to cover the fix in commit 3ddd7f3576
(enable_language: Fix test for working compiler with CMP0126 NEW
behavior, 2021-07-15), as that commit did for the `CSharpOnly` test.
Fixes: #22451
Since commit 2026915f8f (Swift: Propagate Swift_MODULE_DIRECTORY as include
directory, 2020-02-03, v3.18.0-rc1~547^2) we internally call
`GetAllConfigCompileLanguages` on all directly linked targets without
checking if they are interface libraries that don't compile at all.
That violates an internal assumption and assertion.
Fixes: #20977
Teach include directory computation for Swift to implicitly propagate
the `Swift_MODULE_DIRECTORY` of all linked targets as include
directories. This is required to ensure that the swiftmodule of a
linked target is accessible to the compiler of the current target.
Fixes: #19272
The check added in commit b06f4c8a74 (Swift: disallow WIN32_EXECUTABLE
properties, 2019-05-31, v3.15.0-rc1~9^2) makes sense only for
executables because the `WIN32_EXECUTABLE` property is defined only for
them. Running the check on other target types, particularly those that
do not link such as INTERFACE libraries, violates internal assumptions.
In particular, `GetLinkerLanguage` should not be called on such targets.
Fixes: #19528
Create a new CMAKE_Swift_LANGUAGE_VERSION variable to specify the
SWIFT_VERSION attribute in a generated Xcode project. Ideally this
would be a `<LANG>_STANDARD` property but since Swift support is
very minimal we should reserve that property for more complete
treatment later.
Issue: #16326
Allow the `Swift` language to be enabled with the Xcode generator for
Xcode >= 6.1. Reject it on other generators and with older Xcode
versions. Since Apple is the only vendor implementing the language
right now, the compiler id can be just `Apple`.
