linux_dsm_epyc7002/include/linux/compiler-clang.h
Kees Cook 63a0895d96 compiler: Remove uninitialized_var() macro
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

As recommended[2] by[3] Linus[4], remove the macro. With the recent
change to disable -Wmaybe-uninitialized in v5.7 in commit 78a5255ffb
("Stop the ad-hoc games with -Wno-maybe-initialized"), this is likely
the best time to make this treewide change.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Bart van Assche <bvanassche@acm.org>
Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-16 12:35:31 -07:00

64 lines
2.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_COMPILER_TYPES_H
#error "Please don't include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
#endif
/* Compiler specific definitions for Clang compiler */
/* same as gcc, this was present in clang-2.6 so we can assume it works
* with any version that can compile the kernel
*/
#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
/* all clang versions usable with the kernel support KASAN ABI version 5 */
#define KASAN_ABI_VERSION 5
#if __has_feature(address_sanitizer) || __has_feature(hwaddress_sanitizer)
/* Emulate GCC's __SANITIZE_ADDRESS__ flag */
#define __SANITIZE_ADDRESS__
#define __no_sanitize_address \
__attribute__((no_sanitize("address", "hwaddress")))
#else
#define __no_sanitize_address
#endif
#if __has_feature(thread_sanitizer)
/* emulate gcc's __SANITIZE_THREAD__ flag */
#define __SANITIZE_THREAD__
#define __no_sanitize_thread \
__attribute__((no_sanitize("thread")))
#else
#define __no_sanitize_thread
#endif
#if __has_feature(undefined_behavior_sanitizer)
/* GCC does not have __SANITIZE_UNDEFINED__ */
#define __no_sanitize_undefined \
__attribute__((no_sanitize("undefined")))
#else
#define __no_sanitize_undefined
#endif
/*
* Not all versions of clang implement the the type-generic versions
* of the builtin overflow checkers. Fortunately, clang implements
* __has_builtin allowing us to avoid awkward version
* checks. Unfortunately, we don't know which version of gcc clang
* pretends to be, so the macro may or may not be defined.
*/
#if __has_builtin(__builtin_mul_overflow) && \
__has_builtin(__builtin_add_overflow) && \
__has_builtin(__builtin_sub_overflow)
#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
#endif
/* The following are for compatibility with GCC, from compiler-gcc.h,
* and may be redefined here because they should not be shared with other
* compilers, like ICC.
*/
#define barrier() __asm__ __volatile__("" : : : "memory")
#if __has_feature(shadow_call_stack)
# define __noscs __attribute__((__no_sanitize__("shadow-call-stack")))
#endif