compiler: use weak aliases to provide default definitions

This is simpler and more portable.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 7 insertions, 9 deletions

diff --git a/arch_init.h b/arch_init.h
index d9c572a..5fc780c 100644
--- a/arch_init.h
+++ b/arch_init.h
@@ -34,6 +34,6 @@ int tcg_available(void);
 int kvm_available(void);
 int xen_available(void);
 
-CpuDefinitionInfoList GCC_WEAK_DECL *arch_query_cpu_definitions(Error **errp);
+CpuDefinitionInfoList *arch_query_cpu_definitions(Error **errp);
 
 #endif
diff --git a/compiler.h b/compiler.h
index c734a71..58865d6 100644
--- a/compiler.h
+++ b/compiler.h
@@ -50,16 +50,13 @@
 #   define __printf__ __gnu_printf__
 #  endif
 # endif
-#if defined(_WIN32)
-#define GCC_WEAK __attribute__((weak))
-#define GCC_WEAK_DECL GCC_WEAK
-#else
-#define GCC_WEAK __attribute__((weak))
-#define GCC_WEAK_DECL
-#endif
+# define QEMU_WEAK_ALIAS(newname, oldname) \
+        typeof(oldname) newname __attribute__((weak, alias (#oldname)))
 #else
 #define GCC_ATTR /**/
 #define GCC_FMT_ATTR(n, m)
+#define QEMU_WEAK_ALIAS(newname, oldname) \
+        _Pragma("weak " #newname "=" #oldname)
 #endif
 
 #endif /* COMPILER_H */
diff --git a/qmp.c b/qmp.c
index 31bc3bf..df952b6 100644
--- a/qmp.c
+++ b/qmp.c
@@ -466,11 +466,12 @@ DevicePropertyInfoList *qmp_device_list_properties(const char *typename,
     return prop_list;
 }
 
-CpuDefinitionInfoList GCC_WEAK *arch_query_cpu_definitions(Error **errp)
+static CpuDefinitionInfoList *default_arch_query_cpu_definitions(Error **errp)
 {
     error_set(errp, QERR_NOT_SUPPORTED);
     return NULL;
 }
+QEMU_WEAK_ALIAS(arch_query_cpu_definitions, default_arch_query_cpu_definitions);
 
 CpuDefinitionInfoList *qmp_query_cpu_definitions(Error **errp)
 {