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13 daysqemu/compiler: Absorb 'clang-tsa.h'Philippe Mathieu-Daudé1-0/+96
We already have "qemu/compiler.h" for compiler-specific arrangements, automatically included by "qemu/osdep.h" for each source file. No need to explicitly include a header for a Clang particularity. Suggested-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20250117170201.91182-1-philmd@linaro.org>
2025-01-17win32: remove usage of attribute gcc_structPierrick Bouvier1-6/+1
This attribute is not recognized by clang. An investigation has been performed to ensure this attribute has no effect on layout of structures we use in QEMU [1], so it's safe to remove now. In the future, we'll forbid introducing new bitfields in packed struct, as they are the one potentially impacted by this change. [1] https://lore.kernel.org/qemu-devel/66c346de-7e20-4831-b3eb-1cda83240af9@linaro.org/ Reviewed-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Acked-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Acked-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Stefan Weil <sw@weilnetz.de> Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-Id: <20250110203401.178532-2-pierrick.bouvier@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20250116160306.1709518-24-alex.bennee@linaro.org>
2024-08-09include: Fix typo in name of MAKE_IDENTFIER macroPeter Maydell1-1/+1
In commit bb71846325e23 we added some macro magic to avoid variable-shadowing when using some of our more complicated macros. One of the internal components of this is a macro named MAKE_IDENTFIER. Fix the typo in its name: it should be MAKE_IDENTIFIER. Commit created with sed -i -e 's/MAKE_IDENTFIER/MAKE_IDENTIFIER/g' include/qemu/*.h include/qapi/qmp/qobject.h Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-id: 20240801102516.3843780-1-peter.maydell@linaro.org
2024-06-28include: move typeof_strip_qual to compiler.h, use it in QAPI_LIST_LENGTH()Paolo Bonzini1-0/+46
The typeof_strip_qual() is most useful for the atomic fetch-and-modify operations in atomic.h, but it can be used elsewhere as well. For example, QAPI_LIST_LENGTH() assumes that the argument is not const, which is not a requirement. Move the macro to compiler.h and, while at it, move it under #ifndef __cplusplus to emphasize that it uses C-only constructs. A C++ version of typeof_strip_qual() using type traits is possible[1], but beyond the scope of this patch because the little C++ code that is in QEMU does not use QAPI. The patch was tested by changing the declaration of strv_from_str_list() in qapi/qapi-type-helpers.c to: char **strv_from_str_list(const strList *const list) This is valid C code, and it fails to compile without this change. [1] https://lore.kernel.org/qemu-devel/20240624205647.112034-1-flwu@google.com/ Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org> Tested-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-10-17meson: do not use set10Paolo Bonzini1-0/+15
Make all items of config-host.h consistent. To keep the --disable-coroutine-pool code visible to the compiler, mutuate the IS_ENABLED() macro from Linux. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-10-03win32: avoid discarding the exception handlerMarc-André Lureau1-0/+6
In all likelihood, the compiler with lto doesn't see the function being used, from assembly macro __try1. Help it by marking the function has being used. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1904 Fixes: commit d89f30b4df ("win32: wrap socket close() with an exception handler") Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Thomas Huth <thuth@redhat.com>
2023-09-29qobject atomics osdep: Make a few macros more hygienicMarkus Armbruster1-0/+3
Variables declared in macros can shadow other variables. Much of the time, this is harmless, e.g.: #define _FDT(exp) \ do { \ int ret = (exp); \ if (ret < 0) { \ error_report("error creating device tree: %s: %s", \ #exp, fdt_strerror(ret)); \ exit(1); \ } \ } while (0) Harmless shadowing in h_client_architecture_support(): target_ulong ret; [...] ret = do_client_architecture_support(cpu, spapr, vec, fdt_bufsize); if (ret == H_SUCCESS) { _FDT((fdt_pack(spapr->fdt_blob))); [...] } return ret; However, we can get in trouble when the shadowed variable is used in a macro argument: #define QOBJECT(obj) ({ \ typeof(obj) o = (obj); \ o ? container_of(&(o)->base, QObject, base) : NULL; \ }) QOBJECT(o) expands into ({ ---> typeof(o) o = (o); o ? container_of(&(o)->base, QObject, base) : NULL; }) Unintended variable name capture at --->. We'd be saved by -Winit-self. But I could certainly construct more elaborate death traps that don't trigger it. To reduce the risk of trapping ourselves, we use variable names in macros that no sane person would use elsewhere. Here's our actual definition of QOBJECT(): #define QOBJECT(obj) ({ \ typeof(obj) _obj = (obj); \ _obj ? container_of(&(_obj)->base, QObject, base) : NULL; \ }) Works well enough until we nest macro calls. For instance, with #define qobject_ref(obj) ({ \ typeof(obj) _obj = (obj); \ qobject_ref_impl(QOBJECT(_obj)); \ _obj; \ }) the expression qobject_ref(obj) expands into ({ typeof(obj) _obj = (obj); qobject_ref_impl( ({ ---> typeof(_obj) _obj = (_obj); _obj ? container_of(&(_obj)->base, QObject, base) : NULL; })); _obj; }) Unintended variable name capture at --->. The only reliable way to prevent unintended variable name capture is -Wshadow. One blocker for enabling it is shadowing hiding in function-like macros like qdict_put(dict, "name", qobject_ref(...)) qdict_put() wraps its last argument in QOBJECT(), and the last argument here contains another QOBJECT(). Use dark preprocessor sorcery to make the macros that give us this problem use different variable names on every call. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-ID: <20230921121312.1301864-8-armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
2023-09-26compiler: introduce QEMU_ANNOTATEPaolo Bonzini1-0/+6
Allow a more shorter syntax when defining wrapper macros for __attribute__((annotate(...))). Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-30bsd-user: Move PRAGMA_DISABLE_PACKED_WARNING etc to qemu.hWarner Losh1-30/+0
For the moment, move PRAGMA_DISABLE_PACKED_WARNING and PRAGMA_ENABLE_PACKED_WARNING back to bsd-user/qemu.h. Of course, these should be in compiler.h, but that interferes with too many things at the moment, so take one step back to unbreak clang linux-user builds first. Use the exact same version that's in linux-user/qemu.h since that's what should be in compiler.h. Signed-off-by: Warner Losh <imp@bsdimp.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2023-08-28bsd-user: Disable clang warningsKyle Evans1-0/+30
Implement PRAGMA_DISABLE_PACKED_WARNING and PRAGMA_REENABLE_PACKED_WARNING macros in include/qemu/compiler.h. Signed-off-by: Kyle Evans <kevans@FreeBSD.org> Signed-off-by: Karim Taha <kariem.taha2.7@gmail.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Warner Losh <imp@bsdimp.com>
2023-06-23host-utils: Avoid using __builtin_subcll on buggy versions of Apple ClangPeter Maydell1-0/+13
We use __builtin_subcll() to do a 64-bit subtract with borrow-in and borrow-out when the host compiler supports it. Unfortunately some versions of Apple Clang have a bug in their implementation of this intrinsic which means it returns the wrong value. The effect is that a QEMU built with the affected compiler will hang when emulating x86 or m68k float80 division. The upstream LLVM issue is: https://github.com/llvm/llvm-project/issues/55253 The commit that introduced the bug apparently never made it into an upstream LLVM release without the subsequent fix https://github.com/llvm/llvm-project/commit/fffb6e6afdbaba563189c1f715058ed401fbc88d but unfortunately it did make it into Apple Clang 14.0, as shipped in Xcode 14.3 (14.2 is reported to be OK). The Apple bug number is FB12210478. Add ifdefs to avoid use of __builtin_subcll() on Apple Clang version 14 or greater. There is not currently a version of Apple Clang which has the bug fix -- when one appears we should be able to add an upper bound to the ifdef condition so we can start using the builtin again. We make the lower bound a conservative "any Apple clang with major version 14 or greater" because the consequences of incorrectly disabling the builtin when it would work are pretty small and the consequences of not disabling it when we should are pretty bad. Many thanks to those users who both reported this bug and also did a lot of work in identifying the root cause; in particular to Daniel Bertalan and osy. Cc: qemu-stable@nongnu.org Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1631 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1659 Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Tested-by: Daniel Bertalan <dani@danielbertalan.dev> Tested-by: Tested-By: Solra Bizna <solra@bizna.name> Message-id: 20230622130823.1631719-1-peter.maydell@linaro.org
2023-03-20replace TABs with spacesYeqi Fu1-2/+2
Bring the files in line with the QEMU coding style, with spaces for indentation. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/378 Signed-off-by: Yeqi Fu <fufuyqqqqqq@gmail.com> Message-Id: <20230315032649.57568-1-fufuyqqqqqq@gmail.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2022-04-21compiler.h: add QEMU_SANITIZE_{ADDRESS,THREAD}Marc-André Lureau1-0/+8
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>
2022-04-21compiler.h: replace QEMU_NORETURN with G_NORETURNMarc-André Lureau1-2/+0
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>
2022-04-21osdep.h: move qemu_build_not_reached()Marc-André Lureau1-16/+0
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>
2022-03-22Move HOST_LONG_BITS to compiler.hMarc-André Lureau1-0/+5
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>
2022-03-22compiler.h: replace QEMU_SENTINEL with G_GNUC_NULL_TERMINATEDMarc-André Lureau1-2/+0
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>
2022-03-22compiler.h: replace QEMU_WARN_UNUSED_RESULT with G_GNUC_WARN_UNUSED_RESULTMarc-André Lureau1-2/+0
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>
2022-03-22Replace GCC_FMT_ATTR with G_GNUC_PRINTFMarc-André Lureau1-9/+2
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>
2021-06-15configure: Remove probe for _Static_assertRichard Henderson1-11/+0
_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>
2021-06-15qemu/compiler: Remove QEMU_GENERICRichard Henderson1-40/+0
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>
2021-04-17osdep: protect qemu/osdep.h with extern "C"Paolo Bonzini1-0/+6
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>
2021-01-22qemu/compiler: Split out qemu_build_not_reached_alwaysRichard Henderson1-2/+3
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>
2021-01-02cfi: Initial support for cfi-icall in QEMUDaniele Buono1-0/+11
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>
2020-12-18tcg/optimize: Add fallthrough annotationsThomas Huth1-0/+11
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>
2020-12-15compiler.h: remove QEMU_GNUC_PREREQMarc-André Lureau1-11/+0
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>
2020-12-15compiler: remove GNUC checkMarc-André Lureau1-7/+1
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>
2020-12-15compiler.h: explicit case for Clang printf attributeMarc-André Lureau1-12/+12
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>
2020-12-15compiler.h: remove GCC < 3 __builtin_expect fallbackMarc-André Lureau1-4/+0
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>
2020-02-28compiler.h: Don't use compile-time assert when __NO_INLINE__ is definedZenghui Yu1-1/+1
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>
2019-10-28include: Move endof() up from hw/virtio/virtio.hMax Reitz1-0/+7
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>
2019-09-25qemu/compiler.h: Add qemu_build_not_reachedRichard Henderson1-0/+15
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>
2019-09-25cputlb: Disable __always_inline__ without optimizationRichard Henderson1-0/+11
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>
2019-05-07QEMU_PACKED: Remove gcc_struct attribute in Windows non x86 targetsCao Jiaxi1-1/+1
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>
2019-01-22linux-user: Fix compilation with clang 3.4Thomas Huth1-0/+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: 850d5e330a9c68cc998cecc02caf8a3c8d1ee8a3 Reviewed-by: Laurent Vivier <laurent@vivier.eu> Signed-off-by: Thomas Huth <thuth@redhat.com>
2019-01-17qemu/compiler: Define QEMU_NONSTRINGPhilippe Mathieu-Daudé1-0/+15
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>
2018-12-12Remove QEMU_ARTIFICIAL macroThomas Huth1-6/+0
The code that used it has already been removed a while ago with commit dc41aa7d34989b552ef ("tcg: Remove GET_TCGV_* and MAKE_TCGV_*"). Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Thomas Huth <thuth@redhat.com>
2018-12-12includes: Replace QEMU_GNUC_PREREQ with "__has_builtin || !defined(__clang__)"Thomas Huth1-1/+1
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>
2018-10-18tcg: Split CONFIG_ATOMIC128Richard Henderson1-0/+11
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>
2018-10-17qemu/compiler: Wrap __attribute__((flatten)) in a macroThomas Huth1-0/+15
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>
2018-10-05hw/display/qxl: Suppress clang-7 warning about misaligned atomic operationPeter Maydell1-0/+9
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>
2018-06-27compiler: add a sizeof_field() macroStefan Hajnoczi1-0/+2
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>
2018-03-19compiler: Add QEMU_BUILD_BUG_MSG() macroMax Reitz1-3/+9
_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>
2018-02-08lockable: add QemuLockablePaolo Bonzini1-0/+39
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>
2018-02-07ucontext: annotate coroutine stack for ASANMarc-André Lureau1-0/+4
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>
2017-05-05use _Static_assert in QEMU_BUILD_BUG_ONAndreas Grapentin1-1/+3
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>
2017-04-20Drop QEMU_GNUC_PREREQ() checks for gcc older than 4.1Peter Maydell1-8/+0
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>
2017-02-01compiler: expression version of QEMU_BUILD_BUG_ONMichael S. Tsirkin1-0/+3
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>
2017-02-01compiler: rework BUG_ON using a structMichael S. Tsirkin1-3/+7
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>
2017-02-01QEMU_BUILD_BUG_ON: use __COUNTER__Michael S. Tsirkin1-1/+5
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>
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