Define `PROTOBUF_USE_DLLS` on Windows when linking against dynamic
protobuf libraries so that we import symbols from them.
We use the condition `MSVC` to enable this because that is what
the upstream buildsystem uses.
0ba5891ead project: Keep leading `0` in PROJECT_VERSION components
5f84669806 Tests: Factor out RunCMake.project helper macro into module
b1f387a7ea Refactor: Use raw string literals instead of escaping
41b85968d8 Refactor: Use initializer lists instead of `push_back` series
45e85dd2b2 Refactor: Add some `const` to vars
90f91e4d21 Refactor: Replace a "magic" number w/ a named constant
638383c38f Refactor: Eliminate one-time-used variables
9b6a53292f Refactor: Eliminate `sep` from the loop
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !3517
c2c3d22504 Tests: Drop RunCMake workaround for AIX ld warnings about GNU atexit
9f5c2040bf AIX: Explicitly compute executable exports for both XL and GNU
0f150b69d3 AIX: Explicitly compute shared object exports for both XL and GNU
a5bf4e7921 AIX: Drop redundant -brtl flags
9cb5f040d7 XL: De-duplicate shared object creation flags
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !3556
In real projects the variable form should rarely be used because the
decision to export symbols from an executable is very specific.
Remove its main description, which duplicates the `ENABLE_EXPORTS`
target property, and simply reference the property instead.
The module mode fallback added by commit 22e65d10c1 (find_package: Fixed
CMAKE_FIND_PACKAGE_PREFER_CONFIG Module fallback, 2019-06-13,
v3.15.0-rc2~6^2) should not be used unless the `find_package` call
allows module mode. Doing so can lead to infinite recursion if a find
module tries to call config mode with `find_package(... NO_MODULE)`.
Fix the logic and add a test case.
Fixes: #19478
Introduce CMake policy `CMP0096` to make `project()` keep leading zeros
in version components. As a side effect, it now allows really long
version numbers.
Fixes: #19421
Co-Author: Brad King <brad.king@kitware.com>
cd6bd8391a FindMatlab: code comment and ordering of the finders
9e6206c59b FindMatlab: fixing extension bat file invocation error
a9b36ea69f FindMatlab: Fixing compilation issues on Windows
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !3554
Drop the filtering added by commit e22c45d4c9 (Tests: Teach RunCMake to
ignore AIX ld warnings about GNU atexit, 2018-02-28, v3.12.0-rc1~419^2~6).
It is no longer needed now that we compute our own exports on AIX and
do not get these warnings when using shared libraries.
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
On AIX, symbols in shared objects must be exported in order to be
visible to dependents (similar to Windows). The AIX linker provides a
`-bE:...` option to specify a file listing symbols to be exported.
Compilers offer some features to help:
* When the XL compiler is invoked with its `-qmkshrobj`/`-G` options for
creating shared objects (without/with runtime linking), it recognizes
when no explicit `-bE:...` linker option is specified and runs a
`CreateExportList` tool provided with the compiler to compute one from
the object files. Since commit d468a2c2cb (XL: Avoid copying archives
into shared libraries that link them, 2011-04-07, v2.8.5~153^2) CMake
runs `CreateExportList` explicitly to ensure it only looks at the object
files and not any library files.
* When the GNU compiler is invoked with its `-shared` option for creating
shared objects, its internal `collect2` tool recognizes when no explicit
`-bE:...` linker option is specified and computes one itself from the
object files. However, it sometimes includes extra symbols such as
`.__init_aix_libgcc_cxa_atexit`.
Introduce our own internal `ExportImportList` script to compute symbol
export lists from object files. Use a basic implementation for now: it
can be extended as needed later. Update our shared library creation
rules to run the script explicitly for both the XL and GNU compilers.
Issue: #19163
We removed `-brtl` in commit bce7a2a3a5 (AIX: Do not use -brtl to create
shared libraries, 2013-03-11, v2.8.11~103^2~1) but it was added again by
commit f254276fc1 (AIX,HP-UX: Fix RPATH handling when CMP0065 is set to
NEW, 2015-12-11, v3.4.2~4^2). Since the latter commit we initialize the
`CMAKE_{SHARED,MODULE}_LINKER_FLAGS` to use the `-brtl` linker flag.
This is unnecessary because we already use the `-G` linker flag which
implies `-brtl`.
The latter commit also moved `-brtl` to `CMAKE_EXE_LINKER_FLAGS` from
flags that were always included in executable link lines with CMP0065
OLD behavior and are not part of the change intended by CMP0065. Leave
this for now as we've always enabled runtime linking for executables
(and implicitly done so via -G for shared libraries and modules).
Issue: #13997
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
gnaggnoyil