Currently meson only considers what compiler/linker were used by a
Target's immediate sources or objects, not the sources of libraries it's
linked with by the link_with and link_while keywords. This means that if
given 3 libraries: libA which is C++, libB which is C, and libC which is
also C, and libC links with libB which links with libA then linking libC
will be attempted with the C linker, and will fail.
This patch corrects that by adding the compilers used by sub libraries
to the collection of compilers considered by meson when picking a
linker.
This adds a new process_compilers_late method to the BuildTarget class,
which is evaluated after process_kwargs is called. This is needed
because some D options need to be evaluated after compilers are
selected, while for C-like languages we need to check the link* targets
for language requirements, and link* targets are passed by kwargs.
This implementation is recursive, since each Target adds it's parent's
dependencies.
Currently if a target uses link_whole, and one of those archives is a
C++, but the files for the target are C linking will fail when the C
linker attempts to link the C++ files. This patches add
link_whole_targets to the list of languages in the target so the correct
linker will be selected.
Add a boolean 'implib' kwarg to executable(). If true, it is permitted to
use the returned build target object in link_with:
On platforms where this makes sense (e.g. Windows), an implib is generated
for the executable and used when linking. Otherwise, it has no effect.
(Rather than checking if it is a StaticLibrary or SharedLibary, BuildTarget
subclasses gain the is_linkable_target method to test if they can appear in
link_with:)
Also install any executable implib in a similar way to a shared library
implib, i.e. placing the implib in the appropriate place
Add tests of:
- a shared_module containing a reference to a symbol which is known (at link
time) to be provided by the executable
- trying to link with non-implib executables (should fail)
- installing the implib
(This last one needs a little enhancement of the installed file checking as
this is the first install test we have which needs to work with either
MSVC-style or GCC-style implib filenames)
- Adds a `crate_type` kwarg to library targets, allowing the different
types of Rust [linkage][1].
- Shared libraries use the `dylib` crate type by default, but can also
be `cdylib`
- Static libraries use the `rlib` crate type by default, but can also
be `staticlib`
- If any Rust target has shared library dependencies, add the
appropriate linker arguments, including rpath for the sysroot of the
Rust compiler
[1]: https://doc.rust-lang.org/reference/linkage.html
This class now consolidates a lot of the logic that each external
dependency was duplicating in its class definition.
All external dependencies now set:
* self.version
* self.compile_args and self.link_args
* self.is_found (if found)
* self.sources
* etc
And the abstract ExternalDependency class defines the methods that
will fetch those properties. Some classes still override that for
various reasons, but those should also be migrated to properties as
far as possible.
Next step is to consolidate and standardize the way in which we call
'configuration binaries' such as sdl2-config, llvm-config, pkg-config,
etc. Currently each class has to duplicate code involved with that
even though the format is very similar.
Currently only pkg-config supports multiple version requirements, and
some classes don't even properly check the version requirement. That
will also become easier now.
Currently only strings can be passed to the link_depends argument of
executable and *library, which solves many cases, but not every one.
This patch allows generated sources and Files to be passed as well.
On the implementation side, it uses a helper method to keep the more
complex logic separated from the __init__ method. This also requires
that Targets set their link_depends paths as Files, and the backend is
responsible for converting to strings when it wants them.
This adds tests for the following cases:
- Using a file in a subdir
- Using a configure_file as an input
- Using a custom_target as an input
It does not support using a generator as an input, since currently that
would require calling the generator twice, once for the -Wl argument,
and once for the link_depends.
Also updates the docs.
Meson has a common pattern of using 'if len(foo) == 0:' or
'if len(foo) != 0:', however, this is a common anti-pattern in python.
Instead tests for emptiness/non-emptiness should be done with a simple
'if foo:' or 'if not foo:'
Consider the following:
>>> import timeit
>>> timeit.timeit('if len([]) == 0: pass')
0.10730923599840025
>>> timeit.timeit('if not []: pass')
0.030033907998586074
>>> timeit.timeit('if len(['a', 'b', 'c', 'd']) == 0: pass')
0.1154778649979562
>>> timeit.timeit("if not ['a', 'b', 'c', 'd']: pass")
0.08259823200205574
>>> timeit.timeit('if len("") == 0: pass')
0.089759664999292
>>> timeit.timeit('if not "": pass')
0.02340641999762738
>>> timeit.timeit('if len("foo") == 0: pass')
0.08848102600313723
>>> timeit.timeit('if not "foo": pass')
0.04032287199879647
And for the one additional case of 'if len(foo.strip()) == 0', which can
be replaced with 'if not foo.isspace()'
>>> timeit.timeit('if len(" ".strip()) == 0: pass')
0.15294511600222904
>>> timeit.timeit('if " ".isspace(): pass')
0.09413968399894657
>>> timeit.timeit('if len(" abc".strip()) == 0: pass')
0.2023209120015963
>>> timeit.timeit('if " abc".isspace(): pass')
0.09571301700270851
In other words, it's always a win to not use len(), when you don't
actually want to check the length.
Sometimes you want to link to a C++ library that exports C API, which
means the linker must link in the C++ stdlib, and we must use a C++
compiler for linking. The same is also applicable for objc/objc++ etc,
so we can keep using clike_langs for the priority order.
Closes https://github.com/mesonbuild/meson/issues/1653
This detects and allows passing a generated file as a vs_module_def, it
also adds a testcase that tests using configure_file to generate the
.def file.
You can now pass a list of strings to the install_dir: kwarg to
build_target and custom_target.
Custom Targets:
===============
Allows you to specify the installation directory for each
corresponding output. For example:
custom_target('different-install-dirs',
output : ['first.file', 'second.file'],
...
install : true,
install_dir : ['somedir', 'otherdir])
This would install first.file to somedir and second.file to otherdir.
If only one install_dir is provided, all outputs are installed there
(same behaviour as before).
To only install some outputs, pass `false` for the outputs that you
don't want installed. For example:
custom_target('only-install-second',
output : ['first.file', 'second.file'],
...
install : true,
install_dir : [false, 'otherdir])
This would install second.file to otherdir and not install first.file.
Build Targets:
==============
With build_target() (which includes executable(), library(), etc),
usually there is only one primary output. However some types of
targets have multiple outputs.
For example, while generating Vala libraries, valac also generates
a header and a .vapi file both of which often need to be installed.
This allows you to specify installation directories for those too.
# This will only install the library (same as before)
shared_library('somevalalib', 'somesource.vala',
...
install : true)
# This will install the library, the header, and the vapi into the
# respective directories
shared_library('somevalalib', 'somesource.vala',
...
install : true,
install_dir : ['libdir', 'incdir', 'vapidir'])
# This will install the library into the default libdir and
# everything else into the specified directories
shared_library('somevalalib', 'somesource.vala',
...
install : true,
install_dir : [true, 'incdir', 'vapidir'])
# This will NOT install the library, and will install everything
# else into the specified directories
shared_library('somevalalib', 'somesource.vala',
...
install : true,
install_dir : [false, 'incdir', 'vapidir'])
true/false can also be used for secondary outputs in the same way.
Valac can also generate a GIR file for libraries when the `vala_gir:`
keyword argument is passed to library(). In that case, `install_dir:`
must be given a list with four elements, one for each output.
Includes tests for all these.
Closes https://github.com/mesonbuild/meson/issues/705
Closes https://github.com/mesonbuild/meson/issues/891
Closes https://github.com/mesonbuild/meson/issues/892
Closes https://github.com/mesonbuild/meson/issues/1178
Closes https://github.com/mesonbuild/meson/issues/1193
Previously, two functionally identical builds could produce different
build.ninja files. The ordering of the rules themselves doesn't affect
behaviour, but unnecessary changes in commandline arguments can cause
spurious rebuilds and if the ordering of the overall file is stable
than it's easy to use `diff` to compare different build.ninja files
and spot the differences in ordering that are triggering the unnecessary
rebuilds.
Dylan Baker
Niklas Claesson
Alexis Jeandet
Matthias Klumpp
Jussi Pakkanen
Hagai
Jon Turney
Hemmo Nieminen
Adam C. Foltzer
Nirbheek Chauhan
Alistair Thomas
Paulo Antonio Alvarez
Elliott Sales de Andrade
Patrick Griffis
Niclas Moeslund Overby
Sam Thursfield