* Per-config values were added to `AUTO*_EXECUTABLE`.
* Dependency order was refactored for `cmake_autogen` and `cmake_autorcc` to avoid unnecessary rebuilds.
* A new parameter was added for `cmake_autogen` and `cmake_autorcc` to specify the config name of the `auto*_executable` to be used.
* Add `AUTOGEN_BETTER_GRAPH_MULTI_CONFIG` target property to change the behavior of the dependency graph.
* The timestamp target is split into three targets for per-config to avoid redundant `mocs_compilation` builds when `AUTOGEN_BETTER_GRAPH_MULTI_CONFIG` is ON
* Per-config `DEP_FILE_RULE_NAME` values were added to `AutogenInfo.json` for `Multi-Config` usage.
* Some functions were refactored to avoid code duplication.
This commit reimplements fddd0f0443Fixes: #20074
Changing the `timestamp` file to `timestamp_$<CONFIG>` causes some user
projects to break when using Qt versions older than 6.6.
Revert commit fddd0f0443 (Autogen: AUTO*_EXECUTABLE: add support for
per-config values, 2023-06-14, v3.28.0-rc1~96^2~1) pending further
investigation.
Issue: #20074
* Per-config values were added to `AUTO*_EXECUTABLE`.
* Dependency order was refactored for `cmake_autogen` and `cmake_autorcc` to
avoid unnecessary rebuilds.
* A new parameter was added for `cmake_autogen` and `cmake_autorcc` to specify the config name of the `auto*_executable` to be used.
* The timestamp target was split into three targets for per-config to avoid redundant `mocs_compilation` builds.
* Per-config `DEP_FILE_RULE_NAME` values were added to `AutogenInfo.json` for `CMAKE_CROSS_CONFIG` usage.
* Some functions were refactored to avoid code duplication.
Fixes: #20074
#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.
We used to store information for the _autogen target in a CMake script
file AutogenInfo.cmake, which was imported by a temporary cmake instance in
the _autogen target. This introduced the overhead of creating a temporary
cmake instance and inherited the limitations of the CMake language which
only supports lists.
This patch introduces JSON files to pass information to AUTORCC and
autogen_ targets. JSON files are more flexible for passing data, e.g. they
support nested lists.
The patch has the side effects that
- AutogenInfo.cmake is renamed to AutogenInfo.json
- AutogenOldSettings.txt is renamed to AutogenUsed.txt
- RCC<qrcBaseName><checksum>Info.cmake is renamed to
AutoRcc_<qrcBaseName>_<checksum>_Info.json
- RCC<qrcBaseName><checksum>.lock is renamed to
AutoRcc_<qrcBaseName>_<checksum>_Lock.lock
- RCC<qrcBaseName><checksum>Settings.txt is renamed to
AutoRcc_<qrcBaseName>_<checksum>_Used.txt
In AUTORCC with verbose output write the rcc re-generation reason and
the rcc command as on single string to avoid message chopping in concurrent
builds.
New features
------------
CMake's `AUTOMOC` and `AUTOUIC` now cache information extracted when parsing
source files in `CMakeFiles/<ORIGIN>_autogen.dir/ParseCache.txt`.
This leads to faster `<ORIGIN>_autogen` target rebuilds, because source files
will be parsed again only if they're newer than the `ParseCache.txt` file.
The parse cache will be recomputed if it is older than the CMake executable.
`AUTOMOC` and `AUTOUIC` now check if `moc` or `uic` output files are older
than the `moc` or `uic` executable. If an output file is older than the
compiler, it will be regenerated. Therefore if a new `moc` or `uic` version
is installed, all output files will be regenerated.
`AUTOMOC` and `AUTOUIC` error and warning messages are more detailed.
Internal changes
----------------
`moc` and `uic` output file names are not computed in the `_autogen`
target anymore but in `cmQtAutoGenInitializer`. This makes the available at
the configuration stage for improved dependency computations (to be done).
In `AutogenInfo.cmake`, equally sized lists for "source file names",
"source file flags" and "compiler output file names" are passed to the
`_autogen` target. This replaces the separate file lists for
`AUTOMOC` and `AUTOUIC`.
Files times are read from the file system only once by using `cmFileTime`
instances instead of `cmQtAutoGenerator::FileSystem::FileIsOlderThan` calls.
All calls to not thread safe file system functions are moved to non concurrent
fence jobs (see `cmWorkerPool::JobT::IsFence()`). This renders the
`cmQtAutoGenerator::FileSystem` wrapper class obsolete and it is removed.
Instead of composing a single large settings string that is fed to the
`cmCryptoHash`, now all setting sub strings are fed one by one to the
`cmCryptoHash` and the finalized result is stored.
The `std::mutex` in `cmQtAutoGenerator::Logger` is tagged `mutable` and most
`cmQtAutoGenerator::Logger` methods become `const`.
Outlook
-------
This patch provides the framework required to
- extract dependencies from `.ui` files in `AUTOUIC`.
These will help to address issue
#15420 "AUTOUIC: Track uic external inputs".
- generate adaptive `make` and `ninja` files in the `_autogen` target.
These will help to address issue
#16776 "AUTOUIC: Ninja needs two passes to correctly build Qt project".
- generate (possibly empty) `moc` and `uic` files for all headers instead of a
`mocs_compilation.cpp` file.
This will help to address issue
#17277 "AUTOMOC: Provide a option to allow AUTOMOC to compile individual "
"moc_x.cxx instead of including all in mocs_compilation.cxx"
