Since commit
815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h
mutually exclusive") clang no longer reuses the OPTIMIZER_HIDE_VAR macro
from compiler-gcc - instead it gets the version in
include/linux/compiler.h. Unfortunately that version doesn't actually
prevent compiler from optimizing out the variable.
Fix up by moving the macro out from compiler-gcc.h to compiler.h.
Compilers without incline asm support will keep working
since it's protected by an ifdef.
Also fix up comments to match reality since we are no longer overriding
any macros.
Build-tested with gcc and clang.
Fixes:
815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive")
Cc: Eli Friedman <efriedma@codeaurora.org>
Cc: Joe Perches <joe@perches.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
#error "Please don't include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
#endif
-/* Some compiler specific definitions are overwritten here
- * for Clang compiler
- */
+/* Compiler specific definitions for Clang compiler */
+
#define uninitialized_var(x) x = *(&(x))
/* same as gcc, this was present in clang-2.6 so we can assume it works
(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
#ifdef __ECC
-/* Some compiler specific definitions are overwritten here
- * for Intel ECC compiler
- */
+/* Compiler specific definitions for Intel ECC compiler */
#include <asm/intrinsics.h>
#endif
#ifndef OPTIMIZER_HIDE_VAR
-#define OPTIMIZER_HIDE_VAR(var) barrier()
+/* Make the optimizer believe the variable can be manipulated arbitrarily. */
+#define OPTIMIZER_HIDE_VAR(var) \
+ __asm__ ("" : "=r" (var) : "0" (var))
#endif
/* Not-quite-unique ID. */