b0438861ef
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
fffb6e6afd
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
201 lines
6.0 KiB
C
201 lines
6.0 KiB
C
/* compiler.h: macros to abstract away compiler specifics
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2 or later.
|
|
* See the COPYING file in the top-level directory.
|
|
*/
|
|
|
|
#ifndef COMPILER_H
|
|
#define COMPILER_H
|
|
|
|
#define HOST_BIG_ENDIAN (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
|
|
|
|
/* HOST_LONG_BITS is the size of a native pointer in bits. */
|
|
#define HOST_LONG_BITS (__SIZEOF_POINTER__ * 8)
|
|
|
|
#if defined __clang_analyzer__ || defined __COVERITY__
|
|
#define QEMU_STATIC_ANALYSIS 1
|
|
#endif
|
|
|
|
#ifdef __cplusplus
|
|
#define QEMU_EXTERN_C extern "C"
|
|
#else
|
|
#define QEMU_EXTERN_C extern
|
|
#endif
|
|
|
|
#if defined(_WIN32) && (defined(__x86_64__) || defined(__i386__))
|
|
# define QEMU_PACKED __attribute__((gcc_struct, packed))
|
|
#else
|
|
# define QEMU_PACKED __attribute__((packed))
|
|
#endif
|
|
|
|
#define QEMU_ALIGNED(X) __attribute__((aligned(X)))
|
|
|
|
#ifndef glue
|
|
#define xglue(x, y) x ## y
|
|
#define glue(x, y) xglue(x, y)
|
|
#define stringify(s) tostring(s)
|
|
#define tostring(s) #s
|
|
#endif
|
|
|
|
#ifndef likely
|
|
#define likely(x) __builtin_expect(!!(x), 1)
|
|
#define unlikely(x) __builtin_expect(!!(x), 0)
|
|
#endif
|
|
|
|
#ifndef container_of
|
|
#define container_of(ptr, type, member) ({ \
|
|
const typeof(((type *) 0)->member) *__mptr = (ptr); \
|
|
(type *) ((char *) __mptr - offsetof(type, member));})
|
|
#endif
|
|
|
|
#define sizeof_field(type, field) sizeof(((type *)0)->field)
|
|
|
|
/*
|
|
* Calculate the number of bytes up to and including the given 'field' of
|
|
* 'container'.
|
|
*/
|
|
#define endof(container, field) \
|
|
(offsetof(container, field) + sizeof_field(container, field))
|
|
|
|
/* Convert from a base type to a parent type, with compile time checking. */
|
|
#define DO_UPCAST(type, field, dev) ( __extension__ ( { \
|
|
char __attribute__((unused)) offset_must_be_zero[ \
|
|
-offsetof(type, field)]; \
|
|
container_of(dev, type, field);}))
|
|
|
|
#define typeof_field(type, field) typeof(((type *)0)->field)
|
|
#define type_check(t1,t2) ((t1*)0 - (t2*)0)
|
|
|
|
#define QEMU_BUILD_BUG_ON_STRUCT(x) \
|
|
struct { \
|
|
int:(x) ? -1 : 1; \
|
|
}
|
|
|
|
#define QEMU_BUILD_BUG_MSG(x, msg) _Static_assert(!(x), msg)
|
|
|
|
#define QEMU_BUILD_BUG_ON(x) QEMU_BUILD_BUG_MSG(x, "not expecting: " #x)
|
|
|
|
#define QEMU_BUILD_BUG_ON_ZERO(x) (sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)) - \
|
|
sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)))
|
|
|
|
#if !defined(__clang__) && defined(_WIN32)
|
|
/*
|
|
* Map __printf__ to __gnu_printf__ because we want standard format strings even
|
|
* when MinGW or GLib include files use __printf__.
|
|
*/
|
|
# define __printf__ __gnu_printf__
|
|
#endif
|
|
|
|
#ifndef __has_warning
|
|
#define __has_warning(x) 0 /* compatibility with non-clang compilers */
|
|
#endif
|
|
|
|
#ifndef __has_feature
|
|
#define __has_feature(x) 0 /* compatibility with non-clang compilers */
|
|
#endif
|
|
|
|
#ifndef __has_builtin
|
|
#define __has_builtin(x) 0 /* compatibility with non-clang compilers */
|
|
#endif
|
|
|
|
#if __has_builtin(__builtin_assume_aligned) || !defined(__clang__)
|
|
#define HAS_ASSUME_ALIGNED
|
|
#endif
|
|
|
|
#ifndef __has_attribute
|
|
#define __has_attribute(x) 0 /* compatibility with older GCC */
|
|
#endif
|
|
|
|
#if defined(__SANITIZE_ADDRESS__) || __has_feature(address_sanitizer)
|
|
# define QEMU_SANITIZE_ADDRESS 1
|
|
#endif
|
|
|
|
#if defined(__SANITIZE_THREAD__) || __has_feature(thread_sanitizer)
|
|
# define QEMU_SANITIZE_THREAD 1
|
|
#endif
|
|
|
|
/*
|
|
* GCC doesn't provide __has_attribute() until GCC 5, but we know all the GCC
|
|
* versions we support have the "flatten" attribute. Clang may not have the
|
|
* "flatten" attribute but always has __has_attribute() to check for it.
|
|
*/
|
|
#if __has_attribute(flatten) || !defined(__clang__)
|
|
# define QEMU_FLATTEN __attribute__((flatten))
|
|
#else
|
|
# define QEMU_FLATTEN
|
|
#endif
|
|
|
|
/*
|
|
* If __attribute__((error)) is present, use it to produce an error at
|
|
* compile time. Otherwise, one must wait for the linker to diagnose
|
|
* the missing symbol.
|
|
*/
|
|
#if __has_attribute(error)
|
|
# define QEMU_ERROR(X) __attribute__((error(X)))
|
|
#else
|
|
# define QEMU_ERROR(X)
|
|
#endif
|
|
|
|
/*
|
|
* The nonstring variable attribute specifies that an object or member
|
|
* declaration with type array of char or pointer to char is intended
|
|
* to store character arrays that do not necessarily contain a terminating
|
|
* NUL character. 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.
|
|
*/
|
|
#if __has_attribute(nonstring)
|
|
# define QEMU_NONSTRING __attribute__((nonstring))
|
|
#else
|
|
# define QEMU_NONSTRING
|
|
#endif
|
|
|
|
/*
|
|
* Forced inlining may be desired to encourage constant propagation
|
|
* of function parameters. However, it can also make debugging harder,
|
|
* so disable it for a non-optimizing build.
|
|
*/
|
|
#if defined(__OPTIMIZE__)
|
|
#define QEMU_ALWAYS_INLINE __attribute__((always_inline))
|
|
#else
|
|
#define QEMU_ALWAYS_INLINE
|
|
#endif
|
|
|
|
/**
|
|
* In most cases, normal "fallthrough" comments are good enough for
|
|
* switch-case statements, but sometimes the compiler has problems
|
|
* with those. In that case you can use QEMU_FALLTHROUGH instead.
|
|
*/
|
|
#if __has_attribute(fallthrough)
|
|
# define QEMU_FALLTHROUGH __attribute__((fallthrough))
|
|
#else
|
|
# define QEMU_FALLTHROUGH do {} while (0) /* fallthrough */
|
|
#endif
|
|
|
|
#ifdef CONFIG_CFI
|
|
/*
|
|
* If CFI is enabled, use an attribute to disable cfi-icall on the following
|
|
* function
|
|
*/
|
|
#define QEMU_DISABLE_CFI __attribute__((no_sanitize("cfi-icall")))
|
|
#else
|
|
/* If CFI is not enabled, use an empty define to not change the behavior */
|
|
#define QEMU_DISABLE_CFI
|
|
#endif
|
|
|
|
/*
|
|
* Apple clang version 14 has a bug in its __builtin_subcll(); define
|
|
* BUILTIN_SUBCLL_BROKEN for the offending versions so we can avoid it.
|
|
* When a version of Apple clang which has this bug fixed is released
|
|
* we can add an upper bound to this check.
|
|
* See https://gitlab.com/qemu-project/qemu/-/issues/1631
|
|
* and https://gitlab.com/qemu-project/qemu/-/issues/1659 for details.
|
|
* The bug never made it into any upstream LLVM releases, only Apple ones.
|
|
*/
|
|
#if defined(__apple_build_version__) && __clang_major__ >= 14
|
|
#define BUILTIN_SUBCLL_BROKEN
|
|
#endif
|
|
|
|
#endif /* COMPILER_H */
|