blob: 4d36b27214fda629b7808ce662216d61d47e0265 [file] [log] [blame]
/* SPDX-License-Identifier: GPL-2.0 */
#error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
* Common definitions for all gcc versions go here.
#define GCC_VERSION (__GNUC__ * 10000 \
+ __GNUC_MINOR__ * 100 \
#if GCC_VERSION < 40600
# error Sorry, your compiler is too old - please upgrade it.
/* Optimization barrier */
/* The "volatile" is due to gcc bugs */
#define barrier() __asm__ __volatile__("": : :"memory")
* This version is i.e. to prevent dead stores elimination on @ptr
* where gcc and llvm may behave differently when otherwise using
* normal barrier(): while gcc behavior gets along with a normal
* barrier(), llvm needs an explicit input variable to be assumed
* clobbered. The issue is as follows: while the inline asm might
* access any memory it wants, the compiler could have fit all of
* @ptr into memory registers instead, and since @ptr never escaped
* from that, it proved that the inline asm wasn't touching any of
* it. This version works well with both compilers, i.e. we're telling
* the compiler that the inline asm absolutely may see the contents
* of @ptr. See also:
#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
* This macro obfuscates arithmetic on a variable address so that gcc
* shouldn't recognize the original var, and make assumptions about it.
* This is needed because the C standard makes it undefined to do
* pointer arithmetic on "objects" outside their boundaries and the
* gcc optimizers assume this is the case. In particular they
* assume such arithmetic does not wrap.
* A miscompilation has been observed because of this on PPC.
* To work around it we hide the relationship of the pointer and the object
* using this macro.
* Versions of the ppc64 compiler before 4.1 had a bug where use of
* RELOC_HIDE could trash r30. The bug can be worked around by changing
* the inline assembly constraint from =g to =r, in this particular
* case either is valid.
#define RELOC_HIDE(ptr, off) \
({ \
unsigned long __ptr; \
__asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
(typeof(ptr)) (__ptr + (off)); \
/* Make the optimizer believe the variable can be manipulated arbitrarily. */
#define OPTIMIZER_HIDE_VAR(var) \
__asm__ ("" : "=r" (var) : "0" (var))
* A trick to suppress uninitialized variable warning without generating any
* code
#define uninitialized_var(x) x = x
#ifdef __CHECKER__
#define __must_be_array(a) 0
/* &a[0] degrades to a pointer: a different type from an array */
#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
#define __noretpoline __attribute__((indirect_branch("keep")))
#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
#define __optimize(level) __attribute__((__optimize__(level)))
#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
#ifndef __CHECKER__
#define __compiletime_warning(message) __attribute__((warning(message)))
#define __compiletime_error(message) __attribute__((error(message)))
#define __latent_entropy __attribute__((latent_entropy))
#endif /* __CHECKER__ */
* calling noreturn functions, __builtin_unreachable() and __builtin_trap()
* confuse the stack allocation in gcc, leading to overly large stack
* frames, see
* Adding an empty inline assembly before it works around the problem
#define barrier_before_unreachable() asm volatile("")
* Mark a position in code as unreachable. This can be used to
* suppress control flow warnings after asm blocks that transfer
* control elsewhere.
* Early snapshots of gcc 4.5 don't support this and we can't detect
* this in the preprocessor, but we can live with this because they're
* unreleased. Really, we need to have autoconf for the kernel.
#define unreachable() \
do { \
annotate_unreachable(); \
barrier_before_unreachable(); \
__builtin_unreachable(); \
} while (0)
/* Mark a function definition as prohibited from being cloned. */
#define __noclone __attribute__((__noclone__, __optimize__("no-tracer")))
#if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__)
#define __randomize_layout __attribute__((randomize_layout))
#define __no_randomize_layout __attribute__((no_randomize_layout))
/* This anon struct can add padding, so only enable it under randstruct. */
#define randomized_struct_fields_start struct {
#define randomized_struct_fields_end } __randomize_layout;
* When used with Link Time Optimization, gcc can optimize away C functions or
* variables which are referenced only from assembly code. __visible tells the
* optimizer that something else uses this function or variable, thus preventing
* this.
#define __visible __attribute__((externally_visible))
/* gcc version specific checks */
#if GCC_VERSION >= 40900 && !defined(__CHECKER__)
* __assume_aligned(n, k): Tell the optimizer that the returned
* pointer can be assumed to be k modulo n. The second argument is
* optional (default 0), so we use a variadic macro to make the
* shorthand.
* Beware: Do not apply this to functions which may return
* ERR_PTRs. Also, it is probably unwise to apply it to functions
* returning extra information in the low bits (but in that case the
* compiler should see some alignment anyway, when the return value is
* massaged by 'flags = ptr & 3; ptr &= ~3;').
#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
* GCC 'asm goto' miscompiles certain code sequences:
* Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
* (asm goto is automatically volatile - the naming reflects this.)
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
* sparse (__CHECKER__) pretends to be gcc, but can't do constant
* folding in __builtin_bswap*() (yet), so don't set these for it.
#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__)
#define __HAVE_BUILTIN_BSWAP32__
#define __HAVE_BUILTIN_BSWAP64__
#if GCC_VERSION >= 40800
#define __HAVE_BUILTIN_BSWAP16__
#if GCC_VERSION >= 70000
#elif GCC_VERSION >= 50000
#elif GCC_VERSION >= 40902
#if GCC_VERSION >= 40902
* Tell the compiler that address safety instrumentation (KASAN)
* should not be applied to that function.
* Conflicts with inlining:
#define __no_sanitize_address __attribute__((no_sanitize_address))
#if GCC_VERSION >= 50100
* Mark structures as requiring designated initializers.
#define __designated_init __attribute__((designated_init))
#if !defined(__noclone)
#define __noclone /* not needed */
#if !defined(__no_sanitize_address)
#define __no_sanitize_address
* Turn individual warnings and errors on and off locally, depending
* on version.
#define __diag_GCC(version, severity, s) \
__diag_GCC_ ## version(__diag_GCC_ ## severity s)
/* Severity used in pragma directives */
#define __diag_GCC_ignore ignored
#define __diag_GCC_warn warning
#define __diag_GCC_error error
#define __diag_str1(s) #s
#define __diag_str(s) __diag_str1(s)
#define __diag(s) _Pragma(__diag_str(GCC diagnostic s))
#if GCC_VERSION >= 80000
#define __diag_GCC_8(s) __diag(s)
#define __diag_GCC_8(s)