Commit Graph

4 Commits

Author SHA1 Message Date
Alexandru Croitor
bf315c5526 CMake: Make build system of installed Qt more relocatable
Aka handle CMAKE_INSTALL_PREFIX in a more relocatable way.

The following story inspired this change.

If a user wants to build a Qt repo into a different install prefix
than the usual Qt one, this will fail configuration because we
look for various things like syncqt, qdoc, etc relative to
CMAKE_INSTALL_PREFIX, which will now point to a different location
where none of the above tools are located.

The intent for such a use case is to support building Qt packages with
Conan, which sets a random install prefix when configuring a repo.

The idea is to derive the qt prefix dynamically from the
QtBuildInternals package location. Essentially it's a reverse relative
path from the QtBuildInternalsConfig.cmake file to the install prefix
that was specified when initially configuring qtbase.

Once the dynamic prefix is computed (so we know where the possibly
relocated Qt is), we can find tools like syncqt and qdoc.

This is an initial attempt to support a use case like that.

More design work will probably needed in case if tools / libs need to
be found in a location different than the Qt install prefix (so
support for multiple install prefixes / search paths).

An example of such a case would be when building qtdeclarative and
qtquickcontrols2 as Conan packages in one go. Most likely the
qmltyperegistrar tool will be located in the random install prefix
set by Conan, so building qtquickcontrols2 might fail due to not
finding the tool in the original Qt install prefix.

As to the implementation details, the change does the following:
- Dynamically computes and sets the
  QT_BUILD_INTERNALS_RELOCATABLE_INSTALL_PREFIX variable when
  find_package()'ing QtBuildInternals. It's an absolute path
  pointing to where the relocated Qt is.

- When building qtbase this variable is not yet available (due
  to QtBuildInternalsExtra not existing), in that case we set
  the variable to the absolute path of CMAKE_INSTALL_PREFIX
  (but only for the initial qtbase configuration).

- Remove QT_BUILD_INTERNALS_ORIGINAL_INSTALL_PREFIX which was used
  for standalone tests purposes. It's not needed now that we compute
  the location of the Qt prefix dynamically.

- The Unixy qt-cmake and qt-cmake-private shell scripts now
  use a relative path to find the toolchain file we created.

- The toolchain file also dynamically computes the location of the Qt
  packages, and adds them to CMAKE_PREFIX_PATH.

- A lot of existing CMAKE_INSTALL_PREFIX uses are replaced with
  QT_BUILD_INTERNALS_RELOCATABLE_INSTALL_PREFIX. This includes finding
  tool locations, mkspecs dir, path environment setup for tools, etc.

- Some places still use CMAKE_PREFIX_PATH in the following cases
  - When determining paths while configuring qtbase (valid cases)
  - When I wasn't sure what the behavior should be, so I left them
    as-is (an example is documentation generation, do we want to
    install it into the random Conan prefix, or into the main prefix?
    Currently it installs in the random prefix).

Note that relocating a Qt installation does not work for non-prefix /
non-installed builds, due to hardcoded paths to include directories
and libraries in generated FooTargets.cmake files.

Task-number: QTBUG-83999
Change-Id: I87d6558729db93121b1715771034b03ce3295923
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
2020-05-07 15:41:16 +02:00
Alexandru Croitor
c9bea1ad62 Add initial support for CMake "Ninja Multi-Config" generator
This allows doing debug_and_release builds with Ninja on all
platforms.
The "Ninja Multi-Config generator" is available starting with CMake
3.17.

Desired configurations can be set via CMAKE_CONFIGURATION_TYPES.
Possible values: "Release, Debug, RelWithDebInfo, MinRelSize".
For example -DCMAKE_CONFIGURATION_TYPES="Release;Debug".

The first configuration is the 'default' configuration which is
built when calling ninja with no arguments.

To build all targets of a certain configuration use "ninja all:Release"
or "ninja all:Debug".

To build all targets in all configurations use "ninja all:all".

Note that the first configuration influences which configuration of
tools will be used when building the libraries for all configurations.
In simple terms, when configured with
-DCMAKE_CONFIGURATION_TYPES="Release;Debug" the release version of moc
is used by AUTOMOC.
When configured with -DCMAKE_CONFIGURATION_TYPES="Debug;Release"
the debug version of moc is used by AUTOMOC.

Framework builds and Ninja Multi-Config don't currently work together
due to multiple bugs in CMake, which ends up generating an invalid ninja
file with duplicate rules. There are also issues with placement of the
debug artifacts.

This will be handled in a follow up patch after CMake is fixed.

Task-number: QTBUG-76899
Change-Id: If224adc0b71b7d1d6606738101536146aa866cd7
Reviewed-by: Qt CMake Build Bot
Reviewed-by: Leander Beernaert <leander.beernaert@qt.io>
Reviewed-by: Cristian Adam <cristian.adam@qt.io>
2020-01-27 11:47:57 +00:00
Alexandru Croitor
38640f745e Fix toolchain path when doing non-prefix builds
Previously the cmake install prefix was added twice during a non-prefix
build, which evaluated to an incorrect path.

Set another absolute dir variable, and use that instead.

Change-Id: I73099510dadc8f401d5a763f21840c9671686c10
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: Qt CMake Build Bot
2019-07-03 16:09:55 +00:00
Simon Hausmann
2895f3ffaa Generate a toolchain and convenience cmake wrapper
This gets us a step into the direction of convenience that qmake
offered:

    * QtBase is configured with a long command line (especially when
      cross-compiling)
    * Afterwards application developers (or other module builds) can
      just use qmake && make

By generating a toolchain file we can capture vcpkg and toolchain
chain-loading and a shell script can take care of providing the prefix
path.

Change-Id: Ided81f5432cab862306f2bea86cfe8e56adf71b0
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
2019-06-24 14:23:11 +00:00