On AIX, plugins meant to be loaded into executables via `dlopen` must be
linked with access to a list of symbols exported from the executable in
order to use them (when not using runtime linking). The AIX linker
supports specifying this list as an "import file" passed on the command
line either via the `-bI:...` option or (with a leading `#! .` line) as
a normal input file like any other library file.
The linker import file plays the same role on AIX as import libraries do
on Windows. Teach CMake to enable its import library abstraction on AIX
for executables with the `ENABLE_EXPORTS` target property set. Teach
our internal `ExportImportList` script to optionally generate a leading
`#! .` line at the top of the generated export/import list. Update our
rule for linking an executable with exports to generate a public-facing
"import library" implemented as an AIX linker import file.
With this approach, our existing infrastructure for handling import
libraries on Windows will now work for AIX linker import files too:
* Plugins that link to their executable's symbols will be automatically
linked using the import file on the command line.
* The executable's import file will be (optionally) installed and
exported for use in linking externally-built plugins.
This will allow executables and their plugins to build even if we later
turn off runtime linking.
Issue: #19163
On AIX, symbols in executables must be exported in order to be visible
to modules (plugins) they load via `dlopen`. Prior to policy `CMP0065`,
CMake linked all executables with flags to export symbols, but the NEW
behavior for that policy is to do so only for executables that have the
`ENABLE_EXPORTS` target property set. In both cases, CMake has always
used the AIX linker option `-bexpall` option to export symbols from
executables.
This has worked fairly well with the XL compiler, but with the GNU
compiler it works only for C ABI symbols. The reason is that `-bexpall`
does not export symbols starting in `_` but the GNU C++ ABI mangles all
symbols with a leading `_`. Therefore we have only supported C ABI
plugins with the GNU compiler on AIX. Some projects have tried to work
around this by replacing `-bexpall` with `-bexpfull`, but the latter
often exports symbols that we do not want exported.
Avoid using `-bexpall` for executables by instead using by our own
internal `ExportImportList` script to compute symbol export lists from
the object files to be linked into an executable. Pass the explicitly
computed export list to the AIX linker's `-bE:...` option. We already
do this for shared object exports.
Issue: #19163
7ff9ab3b10 Makefile: De-duplicate executable link rule lookup
79f5ef19fe De-duplicate checks for whether a platform uses Windows DLLs
22d3eb5d5e Refactor checks for whether a target has an import library
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !3550
Replace our hard-coded defaults for `/MD` and `/MDd` with a first-class
abstraction to select the runtime library from an enumeration of logical
names. We've long hesitated to do this because the idea of "runtime
library selection" touches on related concepts on several platforms.
Avoid that scope creep by simply defining an abstraction that applies
only when targeting the MSVC ABI on Windows.
Removing the old default flags requires a policy because existing
projects may rely on string processing to edit them and choose a runtime
library under the old behavior. Add policy CMP0091 to provide
compatibility.
Fixes: #19108
To manage the lifetime of `cmTargetInternals`, the private implementation of
`cmTarget`, use `std::unique_ptr<cmTargetInternals>` instead of
`cmTargetInternalPointer`, which is removed.
`cmTarget` is made non-copyable but movable.
965da8d787 cmTarget: Acquire data only when needed
03d17a35b5 cmTarget: Use helper function to append to lists
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !3135
1ed4d48dcf Autogen: Prepend instead of append `mocs_compilation.cpp` to the sources list
a42b700cc2 cmTarget,cmGeneratorTarget: Add optional `before` parameter to AddSource
Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Peter Wu <peter@lekensteyn.nl>
Merge-request: !2815
The new optional `before` parameter in `cmTarget::AddSource` and
`cmGeneratorTarget::AddSource` allows to prepend a source file
to the sources list instead of appending it.
This adds
- the variable ``CMAKE_AUTOGEN_ORIGIN_DEPENDS`` which initializes
- the target property ``AUTOGEN_ORIGIN_DEPENDS``
which controls whether or not the origin target dependencies
should be forwarded to the corresponding ``_autogen`` target.
The default value of ``CMAKE_AUTOGEN_ORIGIN_DEPENDS`` is ``ON``
which corresponds to the behavior that is in place since CMake 3.9.
Closes: #18493
This makes binaries independent of the build directory by not embedding
the build directory via RPATH. The tests are partially based on the
existing RuntimePath test, but with the check moved into a POST_BUILD
command such that it can be skipped when the platform lacks support.
Fixes: #18413
