osdep: set _FORTIFY_SOURCE=2 when optimization is enabled

Currently we set _FORTIFY_SOURCE=2 as a compiler argument when the
meson 'optimization' setting is non-zero, the compiler is GCC and
the target is Linux.

While the default QEMU optimization level is 2, user could override
this by setting CFLAGS="-O0" or --extra-cflags="-O0" when running
configure and this won't be reflected in the meson 'optimization'
setting. As a result we try to enable _FORTIFY_SOURCE=2 and then the
user gets compile errors as it only works with optimization.

Rather than trying to improve detection in meson, it is simpler to
just check the __OPTIMIZE__ define from osdep.h.

The comment about being incompatible with clang appears to be
outdated, as compilation works fine without excluding clang.

In the coroutine code we must set _FORTIFY_SOURCE=0 to stop the
logic in osdep.h then enabling it.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20231003091549.223020-1-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Daniel P. Berrangé 2023-10-03 10:15:49 +01:00 committed by Stefan Hajnoczi
parent da1034094d
commit 9afa888ce0
4 changed files with 8 additions and 14 deletions

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@ -27,6 +27,10 @@
#ifndef QEMU_OSDEP_H
#define QEMU_OSDEP_H
#if !defined _FORTIFY_SOURCE && defined __OPTIMIZE__ && __OPTIMIZE__ && defined __linux__
# define _FORTIFY_SOURCE 2
#endif
#include "config-host.h"
#ifdef NEED_CPU_H
#include CONFIG_TARGET

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@ -479,16 +479,6 @@ if 'cpp' in all_languages
qemu_cxxflags = ['-D__STDC_LIMIT_MACROS', '-D__STDC_CONSTANT_MACROS', '-D__STDC_FORMAT_MACROS'] + qemu_cflags
endif
# clang does not support glibc + FORTIFY_SOURCE (is it still true?)
if get_option('optimization') != '0' and targetos == 'linux'
if cc.get_id() == 'gcc'
qemu_cflags += ['-U_FORTIFY_SOURCE', '-D_FORTIFY_SOURCE=2']
endif
if 'cpp' in all_languages and cxx.get_id() == 'gcc'
qemu_cxxflags += ['-U_FORTIFY_SOURCE', '-D_FORTIFY_SOURCE=2']
endif
endif
add_project_arguments(qemu_cflags, native: false, language: 'c')
add_project_arguments(cc.get_supported_arguments(warn_flags), native: false, language: 'c')
if 'cpp' in all_languages

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@ -22,9 +22,9 @@
*/
/* XXX Is there a nicer way to disable glibc's stack check for longjmp? */
#ifdef _FORTIFY_SOURCE
#undef _FORTIFY_SOURCE
#endif
#define _FORTIFY_SOURCE 0
#include "qemu/osdep.h"
#include <pthread.h>
#include "qemu/coroutine_int.h"

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@ -19,9 +19,9 @@
*/
/* XXX Is there a nicer way to disable glibc's stack check for longjmp? */
#ifdef _FORTIFY_SOURCE
#undef _FORTIFY_SOURCE
#endif
#define _FORTIFY_SOURCE 0
#include "qemu/osdep.h"
#include <ucontext.h>
#include "qemu/coroutine_int.h"