C++ modules have two variants which are of importance to CMake:
- `CXX_MODULES`: interface modules (those using `export module M;`,
`export module M:part;`, or `module M:internal_part;`)
- `CXX_MODULE_HEADER_UNITS`: importable header units
Creating C++ modules or partitions are *not* supported in any other
source listing. This is because the source files must be installed (so
their scope matters), but not part of usage requirements (what it means
for a module source to be injected into a consumer is not clear at this
moment). Due to the way `FILE_SET` works with scopes, they are a perfect
fit as long as `INTERFACE` is not allowed (which it is not).
5fa15ec9f3 Help: Document that target_sources defines [INTERFACE_]HEADER_SETS
c5d4812f20 cmTarget: make HEADER_SETS and INTERFACE_HEADER_SETS read-only
05783b168d cmFileSet: store visibility with the fileset
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !7168
Allow `cmGlobalGenerator`s to decide `HasKnownObjectFileLocation()` per given
`cmTarget`
- `cmGlobalGenerator::HasKnownObjectFileLocation()` now takes an optional `cmGeneratorTarget`
- `cmTarget::HasKnownObjectFileLocation()` added as a shorthand
Revert commit f3ad061858 (Add usage requirements to update direct link
dependencies, 2022-01-12, v3.23.0-rc1~44^2) and the property storage
updates in its predecessor commit 193a999cd5 (cmTarget: Add
INTERFACE_LINK_LIBRARIES_DIRECT{,_EXCLUDE} backtrace storage,
2022-01-06, v3.23.0-rc1~44^2~1) from the 3.23 release branch.
After initial experience using the feature in practice, additional
design considerations have been raised for discussion in the original
issue. To avoid rushing this for the 3.23 series, we've decided to
revert the feature for now so it can be revised for a future release.
Issue: #22496
In commit 55e4753bbb (Refactor cmTargetExport removing
InterfaceIncludeDirecories, 2021-07-20, v3.22.0-rc1~337^2~1) the storage
of `INCLUDES DESTINATION` was moved into each target. However, a target
may be installed in multiple exports, and their `INCLUDES DESTINATION`
should not be mixed.
Convert the IncludeDirectoriesEntries vector to a map and modify access
function to store the directories lists with respect to cmExportTarget
object. This fixes error when the same target is exported more than once
via different exports and each for consequent export its include
directories list grows. Add a test for this case.
Fixes: #23183
Logically revert commit 390a7d8647 (cmTargetPropertyComputer: Implement
GetProperty without cmMakefile, 2016-10-13, v3.8.0-rc1~445^2~9).
It relied on using `cmListFileBacktrace` to get a scope in which to
look up policies.
This does remove a backtrace from `LOCATION` property errors at generate
time, but the backtrace we reported before was incorrect. It pointed at
the addition of a target, not to the reference to the property.
Because of this property in the cmTargetExport struct, exporting targets
is not uniform: top-level ones have to be dealt with via the
cmTargetExport objects, while all linked ones are cmGeneratorTarget
objects. Let's pass this additional includedirectories via a special
target property making handling exported targets uniform.
Previously we only used cmCustomCommandGenerator to evaluate generator
expressions for dependencies. Use it for command lines too. It also
collects target references for us, with backtraces.
#pragma once is a widely supported compiler pragma, even though it is
not part of the C++ standard. Many of the issues keeping #pragma once
from being standardized (distributed filesystems, build farms, hard
links, etc.) do not apply to CMake - it is easy to build CMake on a
single machine. CMake also does not install any header files which can
be consumed by other projects (though cmCPluginAPI.h has been
deliberately omitted from this conversion in case anyone is still using
it.) Finally, #pragma once has been required to build CMake since at
least August 2017 (7f29bbe6 enabled server mode unconditionally, which
had been using #pragma once since September 2016 (b13d3e0d)). The fact
that we now require C++11 filters out old compilers, and it is unlikely
that there is a compiler which supports C++11 but does not support
#pragma once.
7d6861f367 fileapi: Extend codemodel targets with language standard
ba835874a4 Add backtrace support for language standard
e43486a639 cmGeneratorTarget: Clarify name of language property lookup helper
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !4798
In a case like
target_link_libraries(targetInOtherDir PUBLIC "$<1:a;b>")
then all entries in the list need to be looked up in the caller's
scope. Previously our `::@(directory-id)` suffix would apply only
to the last entry. Instead surround the entire entry by a pair
`::@(directory-id);...;::@` so that the `::@` syntax can encode
a directory lookup scope change evaluated as the list is processed.
Fixes: #20204
