Commit Graph

51 Commits

Author SHA1 Message Date
Marc-André Lureau c213ef9a66 compiler.h: add QEMU_SANITIZE_{ADDRESS,THREAD}
Simplify a bit pre-compiler conditions.

For TSAN, QEMU already has CONFIG_TSAN, but it is only set when the
fiber API is present. (I wonder whether supporting TSAN without the
fiber API is really relevant)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-27-marcandre.lureau@redhat.com>
2022-04-21 17:08:52 +04:00
Marc-André Lureau 8905770b27 compiler.h: replace QEMU_NORETURN with G_NORETURN
G_NORETURN was introduced in glib 2.68, fallback to G_GNUC_NORETURN in
glib-compat.

Note that this attribute must be placed before the function declaration
(bringing a bit of consistency in qemu codebase usage).

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Message-Id: <20220420132624.2439741-20-marcandre.lureau@redhat.com>
2022-04-21 17:03:51 +04:00
Marc-André Lureau 94ae6b579d osdep.h: move qemu_build_not_reached()
Move the macro and declaration so it can use glib in the following
patch (it already depends on glib anyway for !optimize)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-19-marcandre.lureau@redhat.com>
2022-04-21 17:03:51 +04:00
Marc-André Lureau 519655970e Move HOST_LONG_BITS to compiler.h
This will help to make common code independent.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2022-03-22 14:46:11 +04:00
Marc-André Lureau 887ce500ef compiler.h: replace QEMU_SENTINEL with G_GNUC_NULL_TERMINATED
One less qemu-specific macro. It also helps to make some headers/units
only depend on glib, and thus moved in standalone projects eventually.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2022-03-22 14:40:51 +04:00
Marc-André Lureau c08401793a compiler.h: replace QEMU_WARN_UNUSED_RESULT with G_GNUC_WARN_UNUSED_RESULT
One less qemu-specific macro. It also helps to make some headers/units
only depend on glib, and thus moved in standalone projects eventually.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2022-03-22 14:40:51 +04:00
Marc-André Lureau 9edc6313da Replace GCC_FMT_ATTR with G_GNUC_PRINTF
One less qemu-specific macro. It also helps to make some headers/units
only depend on glib, and thus moved in standalone projects eventually.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
2022-03-22 14:40:51 +04:00
Richard Henderson c7a7cb5692 configure: Remove probe for _Static_assert
_Static_assert is part of C11, which is now required.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-9-richard.henderson@linaro.org>
2021-06-15 18:31:00 -07:00
Richard Henderson 8bae43fa1a qemu/compiler: Remove QEMU_GENERIC
All previous users now use C11 _Generic.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-8-richard.henderson@linaro.org>
2021-06-15 18:31:00 -07:00
Paolo Bonzini 875df03b22 osdep: protect qemu/osdep.h with extern "C"
System headers may include templates if compiled with a C++ compiler,
which cause the compiler to complain if qemu/osdep.h is included
within a C++ source file's 'extern "C"' block.  Add
an 'extern "C"' block directly to qemu/osdep.h, so that
system headers can be kept out of it.

There is a stray declaration early in qemu/osdep.h, which needs
to be special cased.  Add a definition in qemu/compiler.h to
make it look nice.

config-host.h, CONFIG_TARGET, exec/poison.h and qemu/compiler.h
are included outside the 'extern "C"' block; that is not
an issue because they consist entirely of preprocessor directives.

This allows us to move the include of osdep.h in our two C++
source files outside the extern "C" block they were previously
using for it, which in turn means that they compile successfully
against newer versions of glib which insist that glib.h is
*not* inside an extern "C" block.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210416135543.20382-3-peter.maydell@linaro.org
[PMM: Moved disas/arm-a64.cc osdep.h include out of its extern "C" block;
 explained in commit message why we're doing this]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-04-17 18:44:30 +01:00
Richard Henderson c52ea111e0 qemu/compiler: Split out qemu_build_not_reached_always
Provide a symbol that can always be used to signal an error,
regardless of optimization.  Usage of this should be protected
by e.g. __builtin_constant_p, which guards for optimization.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-01-22 12:48:01 -10:00
Daniele Buono c905a3680d cfi: Initial support for cfi-icall in QEMU
LLVM/Clang, supports runtime checks for forward-edge Control-Flow
Integrity (CFI).

CFI on indirect function calls (cfi-icall) ensures that, in indirect
function calls, the function called is of the right signature for the
pointer type defined at compile time.

For this check to work, the code must always respect the function
signature when using function pointer, the function must be defined
at compile time, and be compiled with link-time optimization.

This rules out, for example, shared libraries that are dynamically loaded
(given that functions are not known at compile time), and code that is
dynamically generated at run-time.

This patch:

1) Introduces the CONFIG_CFI flag to support cfi in QEMU

2) Introduces a decorator to allow the definition of "sensitive"
functions, where a non-instrumented function may be called at runtime
through a pointer. The decorator will take care of disabling cfi-icall
checks on such functions, when cfi is enabled.

3) Marks functions currently in QEMU that exhibit such behavior,
in particular:
- The function in TCG that calls pre-compiled TBs
- The function in TCI that interprets instructions
- Functions in the plugin infrastructures that jump to callbacks
- Functions in util that directly call a signal handler

Signed-off-by: Daniele Buono <dbuono@linux.vnet.ibm.com>
Acked-by: Alex Bennée <alex.bennee@linaro.org
Message-Id: <20201204230615.2392-3-dbuono@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-02 21:03:35 +01:00
Thomas Huth d84568b773 tcg/optimize: Add fallthrough annotations
To be able to compile this file with -Werror=implicit-fallthrough,
we need to add some fallthrough annotations to the case statements
that might fall through. Unfortunately, the typical "/* fallthrough */"
comments do not work here as expected since some case labels are
wrapped in macros and the compiler fails to match the comments in
this case. But using __attribute__((fallthrough)) seems to work fine,
so let's use that instead (by introducing a new QEMU_FALLTHROUGH
macro in our compiler.h header file).

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201211152426.350966-11-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2020-12-18 09:14:23 +01:00
Marc-André Lureau 07b35a23c3 compiler.h: remove QEMU_GNUC_PREREQ
When needed, the G_GNUC_CHECK_VERSION() glib macro can be used instead.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20201210134752.780923-14-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-12-15 12:53:15 -05:00
Marc-André Lureau 4e063f7b29 compiler: remove GNUC check
QEMU requires Clang or GCC, that define and support __GNUC__ extensions.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20201210134752.780923-12-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-12-15 12:53:14 -05:00
Marc-André Lureau 28f86163a4 compiler.h: explicit case for Clang printf attribute
Since commit efc6c07 ("configure: Add a test for the minimum compiler
version"), QEMU explicitely depends on GCC >= 4.8, we could thus drop
earlier version checks. Except clang advertizes itself as GCC 4.2.1.

Since clang doesn't support gnu_printf, make that case explicitely and
drop GCC version check.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20201210134752.780923-8-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-12-15 12:52:11 -05:00
Marc-André Lureau 44cb2c9fe5 compiler.h: remove GCC < 3 __builtin_expect fallback
Since commit efc6c07 ("configure: Add a test for the minimum compiler
version"), QEMU explicitely depends on GCC >= 4.8.

(clang >= 3.4 advertizes itself as GCC >= 4.2 compatible and supports
__builtin_expect too)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20201210134752.780923-4-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-12-15 12:52:09 -05:00
Zenghui Yu b59ea3640c compiler.h: Don't use compile-time assert when __NO_INLINE__ is defined
Our robot reported the following compile-time warning while compiling
Qemu with -fno-inline cflags:

In function 'load_memop',
    inlined from 'load_helper' at /qemu/accel/tcg/cputlb.c:1578:20,
    inlined from 'full_ldub_mmu' at /qemu/accel/tcg/cputlb.c:1624:12:
/qemu/accel/tcg/cputlb.c:1502:9: error: call to 'qemu_build_not_reached' declared with attribute error: code path is reachable
         qemu_build_not_reached();
         ^~~~~~~~~~~~~~~~~~~~~~~~
    [...]

It looks like a false-positive because only (MO_UB ^ MO_BSWAP) will
hit the default case in load_memop() while need_swap (size > 1) has
already ensured that MO_UB is not involved.

So the thing is that compilers get confused by the -fno-inline and
just can't accurately evaluate memop_size(op) at compile time, and
then the qemu_build_not_reached() is wrongly triggered by (MO_UB ^
MO_BSWAP).  Let's carefully don't use the compile-time assert when
no functions will be inlined into their callers.

Reported-by: Euler Robot <euler.robot@huawei.com>
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Message-Id: <20200205141545.180-1-yuzenghui@huawei.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2020-02-28 10:58:41 -08:00
Max Reitz 5d5b33c080 include: Move endof() up from hw/virtio/virtio.h
endof() is a useful macro, we can make use of it outside of virtio.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20191011152814.14791-2-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-28 11:51:07 +01:00
Richard Henderson 560e36d5a4 qemu/compiler.h: Add qemu_build_not_reached
Use this as a compile-time assert that a particular
code path is not reachable.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-09-25 10:19:57 -07:00
Richard Henderson c6b716cdc0 cputlb: Disable __always_inline__ without optimization
This forced inlining can result in missing symbols,
which makes a debugging build harder to follow.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-09-25 10:12:33 -07:00
Cao Jiaxi 48bb55bfaa QEMU_PACKED: Remove gcc_struct attribute in Windows non x86 targets
gcc_struct is for x86 only, and it generates an warning on ARM64 Clang/MinGW targets.

Signed-off-by: Cao Jiaxi <driver1998@foxmail.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-id: 20190503003618.10089-1-driver1998@foxmail.com
[PMM: dropped the slirp change as slirp is now a submodule]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-05-07 12:55:02 +01:00
Thomas Huth 798b858130 linux-user: Fix compilation with clang 3.4
Clang version 3.4.2 does not know the -Wpragmas option yet and bails
out with an error when we try to disable it in linux-user/qemu.h.
Fortunately, clang has a __has_warning() macro which allows us to add
an explicit check for the option that we want to ignore. With that we
can check for the availability of "-Waddress-of-packed-member" properly
and do not need the "-Wpragmas" at all here.

Fixes: 850d5e330a
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2019-01-22 06:26:31 +01:00
Philippe Mathieu-Daudé 1daff2f819 qemu/compiler: Define QEMU_NONSTRING
GCC 8 introduced the -Wstringop-truncation checker to detect truncation by
the strncat and strncpy functions (closely related to -Wstringop-overflow,
which detect buffer overflow by string-modifying functions declared in
<string.h>).

In tandem of -Wstringop-truncation, the "nonstring" attribute was added:

  The nonstring variable attribute specifies that an object or member
  declaration with type array of char, signed char, or unsigned char,
  or pointer to such a type is intended to store character arrays that
  do not necessarily contain a terminating NUL. This is useful in detecting
  uses of such arrays or pointers with functions that expect NUL-terminated
  strings, and to avoid warnings when such an array or pointer is used as
  an argument to a bounded string manipulation function such as strncpy.

  From the GCC manual: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-nonstring-variable-attribute

Add the QEMU_NONSTRING macro which checks if the compiler supports this
attribute.

Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2019-01-17 21:10:57 -05:00
Thomas Huth 78751ea855 Remove QEMU_ARTIFICIAL macro
The code that used it has already been removed a while ago with commit
dc41aa7d34 ("tcg: Remove GET_TCGV_* and MAKE_TCGV_*").

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2018-12-12 10:01:13 +01:00
Thomas Huth f773b423cc includes: Replace QEMU_GNUC_PREREQ with "__has_builtin || !defined(__clang__)"
Since we require GCC version 4.8 or newer now, we can be sure that
the builtin functions are always available on GCC. And for Clang,
we can check the availablility with __has_builtin instead.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2018-12-12 10:01:13 +01:00
Richard Henderson e6cd4bb59b tcg: Split CONFIG_ATOMIC128
GCC7+ will no longer advertise support for 16-byte __atomic operations
if only cmpxchg is supported, as for x86_64.  Fortunately, x86_64 still
has support for __sync_compare_and_swap_16 and we can make use of that.
AArch64 does not have, nor ever has had such support, so open-code it.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-18 19:46:36 -07:00
Thomas Huth 97ff87c0ed qemu/compiler: Wrap __attribute__((flatten)) in a macro
Older versions of Clang (before 3.5) and GCC (before 4.1) do not
support the "__attribute__((flatten))" yet. We don't care about
such old versions of GCC anymore, but since Clang 3.4 is still
used in EPEL for RHEL7 / CentOS 7, we should not use this attribute
directly but with a wrapper macro instead.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2018-10-17 08:36:28 +02:00
Peter Maydell 5a358b39f5 hw/display/qxl: Suppress clang-7 warning about misaligned atomic operation
If QEMU is compiled with clang-7 it results in the warning:

hw/display/qxl.c:1884:19: error: misaligned or large atomic operation
may incur significant performance penalty [-Werror,-Watomic-alignment]
    old_pending = atomic_fetch_or(&d->ram->int_pending, le_events);
                  ^

This is because the Spice headers forgot to define the QXLRam struct
with the '__aligned__(4)' attribute.  clang 7 and newer will thus
warn that the access here to int_pending might not be 4-aligned
(because the QXLRam object d->ram points at might start at a
misaligned address).  In fact we set up d->ram in init_qxl_ram() so
it always starts at a 4K boundary, so we know the atomic access here
is OK.

Newer Spice versions (with Spice commit
beda5ec7a6848be20c0cac2a9a8ef2a41e8069c1) will fix the bug;
for older Spice versions, work around it by telling the compiler
explicitly that the alignment is OK using __builtin_assume_aligned().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180927155538.699-1-peter.maydell@linaro.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2018-10-05 11:21:17 +02:00
Stefan Hajnoczi f18793b096 compiler: add a sizeof_field() macro
Determining the size of a field is useful when you don't have a struct
variable handy.  Open-coding this is ugly.

This patch adds the sizeof_field() macro, which is similar to
typeof_field().  Existing instances are updated to use the macro.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20180614164431.29305-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2018-06-27 13:01:40 +01:00
Max Reitz 9139b56723 compiler: Add QEMU_BUILD_BUG_MSG() macro
_Static_assert() allows us to specify messages, and that may come in
handy.  Even without _Static_assert(), encouraging developers to put a
helpful message next to the QEMU_BUILD_BUG_* may make debugging easier
whenever it breaks.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20180224154033.29559-2-mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2018-03-19 10:00:14 -05:00
Paolo Bonzini e70372fcaf lockable: add QemuLockable
QemuLockable is a polymorphic lock type that takes an object and
knows which function to use for locking and unlocking.  The
implementation could use C11 _Generic, but since the support is
not very widespread I am instead using __builtin_choose_expr and
__builtin_types_compatible_p, which are already used by
include/qemu/atomic.h.

QemuLockable can be used to implement lock guards, or to pass around
a lock in such a way that a function can release it and re-acquire it.
The next patch will do this for CoQueue.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20180203153935.8056-3-pbonzini@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
2018-02-08 09:22:03 +08:00
Marc-André Lureau d83414e1fd ucontext: annotate coroutine stack for ASAN
It helps ASAN to detect more leaks on coroutine stacks, and to get rid
of some extra warnings.

Before:

tests/test-coroutine -p
/basic/lifecycle
/basic/lifecycle: ==20781==WARNING: ASan doesn't fully support
makecontext/swapcontext functions and may produce false positives in
some cases!
==20781==WARNING: ASan is ignoring requested __asan_handle_no_return:
stack top: 0x7ffcb184d000; bottom 0x7ff6c4cfd000; size: 0x0005ecb50000
(25446121472)
False positive error reports may follow
For details see https://github.com/google/sanitizers/issues/189
OK

After:

tests/test-coroutine -p /basic/lifecycle
/basic/lifecycle: ==21110==WARNING: ASan doesn't fully support
makecontext/swapcontext functions and may produce false positives in
some cases!
OK

A similar work would need to be done for sigaltstack & windows fibers
to have similar coverage. Since ucontext is preferred, I didn't bother
checking the other coroutine implementations for now.

Update travis to fix the build with ASAN annotations.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180116151152.4040-4-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-02-07 14:09:24 +01:00
Andreas Grapentin 49e00a1870 use _Static_assert in QEMU_BUILD_BUG_ON
QEMU_BUILD_BUG_ON should use C11's _Static_assert, if the compiler supports it,
to provide more readable messages on failure.

We check for _Static_assert in configure, and set CONFIG_STATIC_ASSERT
accordingly. QEMU_BUILD_BUG_ON invokes _Static_assert if CONFIG_STATIC_ASSERT
is defined, and reverts to the old way otherwise.

That way, systems without C11 conforming compiler will still have the old
messages, as verified by intentionally breaking the configure check.

the following example output was generated by inverting the condition in
QEMU_BUILD_BUG_ON:

without _Static_assert:

> In file included from /qemu/include/qemu/osdep.h:36:0,
>                  from /qemu/qga/commands.c:13:
> /qemu/qga/commands.c: In function ‘qmp_guest_exec_status’:
> /qemu/include/qemu/compiler.h:89:12: error: negative width in bit-field ‘<anonymous>’
>      struct { \
>             ^
> /qemu/include/qemu/compiler.h:96:38: note: in expansion of macro  QEMU_BUILD_BUG_ON_STRUCT’
>  #define QEMU_BUILD_BUG_ON(x) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \
>                                       ^~~~~~~~~~~~~~~~~~~~~~~~
> /qemu/include/qemu/atomic.h:146:5: note: in expansion of macro ‘QEMU_BUILD_BUG_ON’
>      QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *));   \
>      ^~~~~~~~~~~~~~~~~
> /qemu/include/qemu/atomic.h:417:5: note: in expansion of macro ‘atomic_load_acquire’
>      atomic_load_acquire(ptr)
>      ^~~~~~~~~~~~~~~~~~~
> /qemu/qga/commands.c:160:21: note: in expansion of macro ‘atomic_mb_read’
>      bool finished = atomic_mb_read(&gei->finished);
>                      ^~~~~~~~~~~~~~

with _Static_assert:

> In file included from /qemu/include/qemu/osdep.h:36:0,
>                  from /qemu/qga/commands.c:13:
> /qemu/qga/commands.c: In function ‘qmp_guest_exec_status’:
> /qemu/include/qemu/compiler.h:94:30: error: static assertion failed: "not expecting: sizeof(*&gei->finished) > sizeof(void *)"
>  #define QEMU_BUILD_BUG_ON(x) _Static_assert((x), #x)
>                               ^
> /qemu/include/qemu/atomic.h:146:5: note: in expansion of macro ‘QEMU_BUILD_BUG_ON’
>      QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *));   \
>      ^~~~~~~~~~~~~~~~~
> /qemu/include/qemu/atomic.h:417:5: note: in expansion of macro ‘atomic_load_acquire’
>      atomic_load_acquire(ptr)
>      ^~~~~~~~~~~~~~~~~~~
> /qemu/qga/commands.c:160:21: note: in expansion of macro ‘atomic_mb_read’
>      bool finished = atomic_mb_read(&gei->finished);
>                      ^~~~~~~~~~~~~~

Signed-off-by: Andreas Grapentin <andreas@grapentin.org>
Message-Id: <20170314165953.18506-1-andreas@grapentin.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-05-05 12:09:59 +02:00
Peter Maydell fa54abb8c2 Drop QEMU_GNUC_PREREQ() checks for gcc older than 4.1
We already require gcc 4.1 or newer (for the atomic
support), so the fallback codepaths for older gcc
versions than that are now dead code and we can
just delete them.

NB: clang reports itself as gcc 4.2 (regardless of
clang version), so clang won't be using the fallbacks
either.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
2017-04-20 18:33:33 +01:00
Michael S. Tsirkin d757573e69 compiler: expression version of QEMU_BUILD_BUG_ON
QEMU_BUILD_BUG_ON uses a typedef in order to be safe
to use outside functions, but sometimes it's useful
to have a version that can be used within an expression.
Following what Linux does, introduce QEMU_BUILD_BUG_ON_ZERO
that return zero after checking condition at build time.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
2017-02-01 03:37:17 +02:00
Michael S. Tsirkin f291887e8e compiler: rework BUG_ON using a struct
There are theoretical concerns that some compilers might not trigger
build failures on attempts to define an array of size (x ? -1 : 1) where
x is a variable and make it a variable sized array instead. Let rewrite
using a struct with a negative bit field size instead as there are no
dynamic bit field sizes.  This is similar to what Linux does.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
2017-02-01 03:37:17 +02:00
Michael S. Tsirkin 60abf0a5e0 QEMU_BUILD_BUG_ON: use __COUNTER__
Some headers use QEMU_BUILD_BUG_ON. This causes a problem
if the C file including that header happens to have
QEMU_BUILD_BUG_ON at the same line number.

Fix using a widely available extension: __COUNTER__.
If unavailable, provide a stub.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2017-02-01 03:37:17 +02:00
Michael S. Tsirkin f298318284 compiler: drop ; after BUILD_BUG_ON
All users include the trailing ; anyway, let's require that -
it seems cleaner.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
2017-01-31 15:57:27 +02:00
Felipe Franciosi cc9d8a3b2c compiler: Swap 'public domain' header for license
As discussed on the list [1], having a comment stating that this file
is "public domain" is arguably wrong and not legally binding. This patch
replaces that comment with a clear GPLv2+ license as proposed in [2].

[1] http://lists.nongnu.org/archive/html/qemu-devel/2016-09/msg06151.html
[2] http://lists.nongnu.org/archive/html/qemu-devel/2016-09/msg06217.html

Worth noting, compiler.h was originally created on 5c026320 by splitting
qemu-common.h. At the time, qemu-common.h was already GPLv2+.

Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Message-Id: <1474642971-11866-1-git-send-email-felipe@nutanix.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:29 +02:00
Paolo Bonzini 8bff06a0bb compiler: never omit assertions if using a static analysis tool
Assertions help both Coverity and the clang static analyzer avoid
false positives, but on the other hand both are confused when
the condition is compiled as (void)(x != FOO).  Always expand
assertion macros when using Coverity or clang, through a new
QEMU_STATIC_ANALYSIS preprocessor symbol.

This fixes a couple false positives in TCG.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-17 09:59:21 +02:00
Emilio G. Cota 911a4d2215 compiler.h: add QEMU_ALIGNED() to enforce struct alignment
Reviewed-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1465412133-3029-2-git-send-email-cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-06-11 22:59:33 +00:00
Peter Maydell 90ce6e2644 include: Clean up includes
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

NB: If this commit breaks compilation for your out-of-tree
patchseries or fork, then you need to make sure you add
#include "qemu/osdep.h" to any new .c files that you have.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
2016-02-23 12:43:05 +00:00
Eric Blake 888ea96aae build: Don't redefine 'inline'
Actively redefining 'inline' is wrong for C++, where gcc has an
extension 'inline namespace' which fails to compile if the
keyword 'inline' is replaced by a macro expansion.  This will
matter once we start to include "qemu/osdep.h" first from C++
files, depending also on whether the system headers are new
enough to be using the gcc extension.

But rather than just guard things by __cplusplus, let's look at
the overall picture.  Commit df2542c737 in 2007 defined 'inline'
to the gcc attribute __always_inline__, with the rationale "To
avoid discarded inlining bug".  But compilers have improved since
then, and we are probably better off trusting the compiler rather
than trying to force its hand.

So just nuke our craziness.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1455043788-28112-1-git-send-email-eblake@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-02-16 12:07:03 +00:00
Peter Maydell 24134c4e91 compiler.h: Use glue() in QEMU_BUILD_BUG_ON define
Rather than rolling custom concatenate-strings macros for the
QEMU_BUILD_BUG_ON macro to use, use the glue() macro we already
have (since it's now available to us in this header).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
2015-08-19 16:29:53 +01:00
Peter Maydell 4912086865 osdep.h: Move some compiler-specific things to compiler.h
osdep.h has a few things which are really compiler specific;
move them to compiler.h, and include compiler.h from osdep.h.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
2015-08-19 16:29:53 +01:00
Daniel P. Berrange a31bdae5a7 qom: Add object_new_with_props() / object_new_withpropv() helpers
It is reasonably common to want to create an object, set a
number of properties, register it in the hierarchy and then
mark it as complete (if a user creatable type). This requires
quite a lot of error prone, verbose, boilerplate code to achieve.

First a pair of functions object_set_props() / object_set_propv()
are added which allow for a list of objects to be set in
one single API call.

Then object_new_with_props() / object_new_with_propv() constructors
are added which simplify the sequence of calls to create an
object, populate properties, register in the object composition
tree and mark the object complete, into a single method call.

Usage would be:

   Error *err = NULL;
   Object *obj;
   obj = object_new_with_propv(TYPE_MEMORY_BACKEND_FILE,
                               object_get_objects_root(),
                               "hostmem0",
                               &err,
                               "share", "yes",
                               "mem-path", "/dev/shm/somefile",
                               "prealloc", "yes",
                               "size", "1048576",
                               NULL);

Note all property values are passed in string form and will
be parsed into their required data types, using normal QOM
semantics for parsing from string format.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2015-06-19 18:42:18 +02:00
Richard Henderson 58099c8066 qemu/compiler: Define QEMU_ARTIFICIAL
The combination of always_inline + artificial allows tiny inline
functions to be written that do not interfere with debugging.
In particular, gdb will not step into an artificial function.

The always_inline attribute was introduced in gcc 4.2,
and the artificial attribute was introduced in gcc 4.3.

Signed-off-by: Richard Henderson <rth@twiddle.net>
2014-09-29 14:55:28 -04:00
Stefan Weil 87e613ea9e audio: Replace static functions in header file by macros, remove GCC_ATTR
Using macros instead of static functions for dolog and for ldebug
simplifies the code and can also reduce the total code size.

GCC_ATTR was only used in audio_int.h, so it is now unused and
the definition can be removed from compiler.h.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2013-06-21 22:52:50 +04:00
Paolo Bonzini 99835e0084 compiler: fix warning with GCC 4.8.0
GCC 4.8.0 introduces a new warning:

    block/qcow2-snapshot.c: In function 'qcow2_write_snapshots’:
    block/qcow2-snapshot.c:252:18: error: typedef 'qemu_build_bug_on__253'
              locally defined but not used [-Werror=unused-local-typedefs]
         QEMU_BUILD_BUG_ON(offsetof(QCowHeader, snapshots_offset) !=
                  ^
    cc1: all warnings being treated as errors

(Caret diagnostics aren't perfect yet with macros... :)) Work around it
with __attribute__((unused)).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1364391272-1128-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-27 10:10:14 -05:00