Commit 798b8581 authored by Thomas Huth's avatar Thomas Huth
Browse files

linux-user: Fix compilation with clang 3.4 



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: 850d5e33
Reviewed-by: default avatarLaurent Vivier <laurent@vivier.eu>
Signed-off-by: default avatarThomas Huth <thuth@redhat.com>
parent b0b36c02

include/qemu/compiler.h

+4 −0
Original line number Diff line number Diff line
@@ -113,6 +113,10 @@ 
#define GCC_FMT_ATTR(n, m)

#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

linux-user/qemu.h

+1 −5
Original line number Diff line number Diff line
@@ -474,17 +474,13 @@ static inline int access_ok(int type, abi_ulong addr, abi_ulong size) 
 *   functions than host-endian unaligned load/store plus tswapN.

 * - The pragmas are necessary only to silence a clang false-positive

 *   warning: see https://bugs.llvm.org/show_bug.cgi?id=39113 .

 * - We have to disable -Wpragmas warnings to avoid a complaint about

 *   an unknown warning type from older compilers that don't know about

 *   -Waddress-of-packed-member.

 * - gcc has bugs in its _Pragma() support in some versions, eg

 *   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 -- so we only

 *   include the warning-suppression pragmas for clang

 */

#ifdef __clang__

#if defined(__clang__) && __has_warning("-Waddress-of-packed-member")

#define PRAGMA_DISABLE_PACKED_WARNING                                   \

    _Pragma("GCC diagnostic push");                                     \

    _Pragma("GCC diagnostic ignored \"-Wpragmas\"");                    \

    _Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\"")



#define PRAGMA_REENABLE_PACKED_WARNING          \