For PE/COFF it is not possible to allow undefined symbols, so do not
try to use the option to do so.
While gcc ld silently ignores it, this is not the case for the llvm
linker.
Fix#4415
* This helps with reproducibility on macOS in the same way
`$ORIGIN` improves reproducibility on Linux-like systems.
* This makes the build-tree more resilient to users injecting
rpaths via `LDFLAGS`. Currently Meson on macOS crashes when
a build-tree rpath and a user-provided `-Wl,-rpath` in
LDFLAGS collide, leading to `install_name_tool` failures.
While this still does not solve the root cause, it makes
the occurrence much less likely, as users will generally
pass absolute `-Wl,-rpath` arguments into Meson.
Occasionally Darwin libraries can be .so rather than .dylib e.g. tensorflow_cc.so
tensorflow_cc is a c++ API for Tensorflow (https://github.com/FloopCZ/tensorflow_cc)
which was primarily written for Linux but is also compilable on Darwin. Possibly
through laziness, possibly just to have consistent filenames, the developers did not
opt to change the suffix from the Linux default when this is compiled on Darwin.
Also, the Darwin linker will find libraries with a .so suffix if they are
in its path. find_library() needs to match the linker behaviour.
In get_library_dirs() we are trusting the compiler to return a correct
list of directories to search for libraries, based on whether or not
we are compiling 64-bit or 32-bit. Unfortunately, this is often not the
case, as 64-bit libraries often are returned when compiling with -m32 on
a 64-bit OS.
Since system directories do not contain a mix of libraries, the solution
here is to check each directory, by picking a .so file in the directory
and checking whether its 64-bit or 32-bit. If we can't determine if we
want 32-bit or 64-bit, just skip the checks and assume the directory is
good.
Using the -pthread argument is not needed with clang when compiling for
darwin, and it results in the warning:
warning: argument unused during compilation: '-pthread'
GNU binutils ld silently ignores -rpath flags when targeting windows
(and it is already commented within ninjabackend.py that rpath as
concept doesn't exist on windows), and build_rpath_args in
VisualStudioCCompiler also returns an empty array. Therefore skip
this flag altogether.
This fixes linking with lld in MinGW mode, which doesn't support the
rpath flag.
--as-needed controls ELF-specific functionality (the emission of DT_NEEDED
tags)
--no-undefined is effectively always on for PE/COFF, as the linkage model
always requires symbols to be defined
binutils ld silently ignores these flags for PE targets, but lld warns that
it's ignoring them, so just don't bother emitting them for PE targets.
D compilers are configured to have highest priority when chosing linker
for targets mixing C/C++/D code and before this change meson would fail
to configure gtest target that uses D library as a dependency.
* Enums are strongly typed and make the whole
`gcc_type`/`clang_type`/`icc_type` distinction
redundant.
* Enums also allow extending via member functions,
which makes the code more generalisable.
It's fairly common on Linux and *BSD platforms to check for these
attributes existence, so it makes sense to me to have this checking
build into meson itself. Autotools also has a builtin for handling
these, and by building them in we can short circuit cases that we know
that these don't exist (MSVC).
Additionally this adds support for two common MSVC __declspec
attributes, dllimport and dllexport. This implements the declspec
version (even though GCC has an __attribute__ version that both it and
clang support), since GCC and Clang support the MSVC version as well.
Thus it seems reasonable to assume that most projects will use the
__declspec version over teh __attribute__ version.
We now use the soversion to set compatibility_version and
current_version by default. This is the only sane thing we can do by
default because of the restrictions on the values that can be used for
compatibility and current version.
Users can override this value with the `darwin_versions:` kwarg, which
can be a single value or a two-element list of values. The first one
is the compatibility version and the second is the current version.
Fixes https://github.com/mesonbuild/meson/issues/3555
Fixes https://github.com/mesonbuild/meson/issues/1451
fixes#4032: meson now checks properly for the compiler used to compile dub dependencies
fixes#3568: applied the following patch https://paste.debian.net/1039317/
meson now adds flags for native dependencies required by dub modules
meson now checks for the D version implemented by the compiler used to build dub dependencies (execpt gdc which doesn't support this)
* The current version matching logic is brittle
with respect to Clang. LLVM and Apple Clang use
slightly different but nowadays overlapping
version ranges. Instead, we now just check whether
the compiler supports the given `-std=` variant
and try its respective fallback instead of
testing version ranges.
* Currently, RPATHs coming from dependencies and
`build_rpath` provided by the user might contain
the same path. Apple's `install_name` tool is
allergic to providing the same argument twice
when removing RPATHs:
error: install_name_tool: "-delete_rpath /usr/lib" specified more than once
Treat it the same as -lfoo by deduping and adding to --start/end-group
Reported at https://gitlab.gnome.org/GNOME/glib/issues/1496
We don't do any advanced transformation for MSVC or de-dup because
this is a very rare syntax.
Add a keyword argument to to_native() to operate on a copy so that we
can call it multiple times instead of modifying the original compiler
args while iterating.
This is used in the unit test, and might be used in Meson at some
point too.
