armv5 Linux systems implement __sync_bool_compare_and_swap() and
friends by calling a function provided by the kernel. This is not
technically an atomic intrinsic, so gcc doesn't define
__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 in this case, but it's good
enough for us. Extend the current Android special case to cover
GNU/Linux too.
The possibilities are:
* __sync_foo detected and __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 predefined:
calls to __atomic_foo or __sync_foo primitives are inlined into user
code by gatomic.h
* __sync_foo detected but __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 not
predefined: user code has an extern reference to g_atomic_foo(),
which calls __atomic_foo or __sync_foo because we defined
__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 when compiling GLib itself
* Windows: user code has an extern reference to g_atomic_foo(),
which calls InterlockedFoo()
* !defined(G_ATOMIC_LOCK_FREE): user code has an extern reference to
g_atomic_foo(), which emulates atomic operations with a mutex
Signed-off-by: Simon McVittie <smcv@collabora.com>
Closes: #1576
This is enough for most Debian buildds, including embedded devices
like mips and powerpcspe. It is not enough for hppa (PA-RISC), but that
architecture is so uniquely slow that it might make more sense to
special-case it downstream.
Signed-off-by: Simon McVittie <smcv@collabora.com>
Partial revert of commit a7a6449f4d63357bf3a66140e9fb3ccb18611c0b.
Checking for the availability of m4 for installing m4 macro files
creates an implicit dependency on m4 even if GLib does not need it; this
prevents building GLib and then installing Autotools in order to build a
project that depends on GLib.
Closes#1520
We already set -Wformat=2, which implies -Wformat-security, so there’s
no need to test for and set -Wformat-security separately.
The test for -Wformat-security never worked anyway, since gcc complains
if it’s specified without also setting -Wformat to some value. The
complaint causes configure.ac/meson.build to assume the option doesn’t
work.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
https://gitlab.gnome.org/GNOME/glib/issues/656
This was a leftover from use of the __int64 type, which was removed
recently in commit 7e821441c482917e54435a07893272d87d3ad9e5.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
https://gitlab.gnome.org/GNOME/glib/issues/1313
I can’t see this being used anywhere in GLib, or in my /usr/include
directory. I’m also not sure how configure.ac ends up defining it — it’s
certainly as a side-effect of something, and not deliberate.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
https://gitlab.gnome.org/GNOME/glib/issues/1313
Previously we weren’t checking for it in meson.build (but were checking
for it in configure.ac, courtesy of glib-gettext.m4). Roughly emulate
the checks from glib-gettext.m4, checking for bind_textdomain_codeset()
in whichever libintl implementation we found ngettext() in.
meson.build still doesn’t implement the full set and order of checks in
glib-gettext.m4; there’s still a FIXME about that in meson.build.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
https://gitlab.gnome.org/GNOME/glib/issues/1313
Previously it was hard-coded to true, rather than being based on the
calculations actually made by meson.build.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
https://gitlab.gnome.org/GNOME/glib/issues/1313
This is equivalent to the AC_FUNC_PRINTF_UNIX98 macro which we use in
configure.ac. There may still be some obscure Unix platforms which don’t
natively support positional parameters, 20 years on.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
https://gitlab.gnome.org/GNOME/glib/issues/1313
The goal of this commit is to reduce differences between the autotools and meson build.
With autotools AC_FUNC_ALLOCA was used which defines HAVE_ALLOCA_H, HAVE_ALLOCA,
C_ALLOCA. meson tried to replicate that with has_function() but alloca can be a macro
and and is named _alloca under Windows. Since we require a working alloca anyway
and only need to know if the header exists replace AC_FUNC_ALLOCA with a simple
AC_CHECK_HEADERS.
There is still one user of HAVE_ALLOCA in the embedded gnulib, but since alloca is
always provided through galloca.h just force define HAVE_ALLOCA there and add a comment.
The docs were mentioning alloca as an example for cross compiling. Since that variable no
longer exists now replace it with another one.
This is what Autotools does, and it's what all consumers of the
GModule API expect. Without this change, people on macOS upgrading to
a GLib built with Meson will find that their plugins no longer load.
Projects that use Meson and the `g_module_build_path()` API such as
glib-networking should pass `name_suffix:` to `shared_module()` to
ensure that plugins continue to be called libfoo.so on macOS.
New GModule API will eventually be added to address this.
See also:
https://gitlab.gnome.org/GNOME/glib/issues/1413a3d81719fe/meson.build (L108)
Check for compile warnings when assigning an int64_t* to a long*,
make gint64 a long long if they occur and assigning an int64_t* to
a long long* doesn't.
Modified by Philip Withnall <withnall@endlessm.com> to support Meson as
well as autotools.
https://gitlab.gnome.org/GNOME/glib/issues/972
The autotools build set it by default and we use off_t in various places,
even on Windows. Also set it with the meson build to avoid any regressions.
Ideally we shouldn't use off_t and use 64bit capable API on Windows instead, so
we get large file support with MSVC as well.
The new python module, added with 0.46, works with Python 2 and 3 and
allows to pass a path for the interpreter to use, if the need arises.
Previously the meson build set PYTHON, used in the shebang line of
the scripts installed by glib, to the full path of the interpreter.
The new meson module doesn't expose that atm, but we should set it to
a executable name anyway, and not a full path.
When compiling third-party projects with -Wbad-function-cast, the inline
g_atomic_pointer_get() implementation which uses C11 __atomic_load*()
calls on GCC was causing compilation errors like:
error: cast from function call of type ‘long unsigned int’ to non-matching type ‘void *’
While we don’t want to compile all of GLib with -Wbad-function-cast, we
should support its headers being included in projects which do enable
that warning.
It doesn’t seem to be possible to cast away the warning (e.g. by casting
the function’s result through (void)), so we have to assign to an
intermediate integer of the right size first.
The same has to be done for the bool return value from
__sync_bool_compare_and_swap(). In that case, casting from bool to
gboolean raises a -Wbad-function-cast warning, since gboolean is
secretly int.
The atomic tests have been modified to enable -Wbad-function-cast to
catch regressions of this in future. The GLib build has conversely been
modified to set -Wno-bad-function-cast, just in case people have it set
in their environment CFLAGS.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
https://gitlab.gnome.org/GNOME/glib/issues/1041
This requires meson >= 0.47.0 otherwise building the doc fails:
https://github.com/mesonbuild/meson/issues/3379
While at it, no need to to pass --prefix --libdir to meson, other CIs
don't have them.
When the amount of free memory on the system is somewhat low, gnome-shell
will sometimes fail to launch apps, reporting the error:
fork(): Cannot allocate memory
fork() is failing here because while cloning the process virtual address
space, Linux worries that the thread being forked may end up COWing the
entire address space of the parent process (gnome-shell, which is
memory-hungry), and there is not enough free memory to permit that to
happen.
In this case we are simply calling fork() in order to quickly call exec(),
which will throw away the entirity of the duplicated VM, so we should
look for ways to avoid the overcommit check.
The well known solution to this is to use clone(CLONE_VM) or vfork(), which
completely avoids creating a new memory address space for the child.
However, that comes with a bunch of caveats and complications:
https://gist.github.com/nicowilliams/a8a07b0fc75df05f684c23c18d7db234https://ewontfix.com/7/
In 2016, glibc's posix_spawn() was rewritten to use this approach
while also resolving the concerns.
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=9ff72da471a509a8c19791efe469f47fa6977410
I experimented with a similar approach in glib, but it was not practical
because glibc has several items of important internal knowledge (such as
knowing which signals should be given special treatment because they are
NPTL implementation details) that are not cleanly exposed elsewhere.
Instead, this patch adapts the gspawn code to use posix_spawn() where
possible, which will reap the benefits of that implementation.
The posix_spawn API is more limited than the gspawn API though,
partly due to natural limitations of using CLONE_VM, so the posix_spawn
path is added as a separate codepath which is only executed when the
conditions are right. Callers such as gnome-shell will have to be modified
to meet these conditions, such as not having a child_setup function.
In addition to allowing for the gnome-shell "Cannot allocate memory"
failure to be avoided, this should result in a general speedup in this
area, because fork()'s behaviour of cloning the entire VM space
has a cost which is now avoided. posix_spawn() has also recently
been optimized on OpenSolaris as the most performant way to spawn
a child process.
We don’t strictly require this, but given that our CI runs it, we
essentially never test with 0.46.0, so it might as well be broken.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
We have not updated nor used this script for a long time, and nowadays
Meson makes it much easier to build on Windows for either Visual Studio
or MinGW, even straight from a GIT checkout, so it's about time that we
drop the glib-zip script from the source tree.
Autoconf macro AC_HEADER_MAJOR doesn't define a macro in config.h when
major is defined in sys/types.h. This was not a problem because major
is assumed to be always available. However, commit aefffa3fbc3901
changes this assumption in order to fix build on systems without major,
which causes code using major to be disabled on systems putting major
in sys/types.h.
This commit defines a new macro MAJOR_IN_TYPES for both autotools and
meson builds to make major useful on these systems again.
