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[Qemu-devel] [PATCH v2 3/4] configure: silence glib unknown attribute __
From: |
John Snow |
Subject: |
[Qemu-devel] [PATCH v2 3/4] configure: silence glib unknown attribute __alloc_size__ |
Date: |
Wed, 18 Mar 2015 18:43:44 -0400 |
v2: We must test compilation with the right glib flags,
otherwise the test compile will always fail.
In addition, test-compile the warning flag to make
sure we can use it.
The glib headers use GCC attributes. Unfortunately the __GNUC__ and
__GNUC_MINOR__ version macros are also defined by clang, but clang
doesn't support the same attributes as GCC.
clang 3.5.0 does not support the __alloc_size__ attribute:
https://github.com/llvm-mirror/clang/commit/c047507a9a79e89fc8339e074fa72822a7e7ea73
The following warning is produced:
gstrfuncs.h:257:44: warning: unknown attribute '__alloc_size__' ignored
[-Wunknown-attributes]
G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(2);
gmacros.h:67:45: note: expanded from macro 'G_GNUC_ALLOC_SIZE'
#define G_GNUC_ALLOC_SIZE(x) __attribute__((__alloc_size__(x)))
This patch checks whether glib headers cause warnings and disables
-Wunknown-attributes if that is the case.
Signed-off-by: Stefan Hajnoczi <address@hidden>
Signed-off-by: John Snow <address@hidden>
---
configure | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/configure b/configure
index 062df84..9db53ba 100755
--- a/configure
+++ b/configure
@@ -2784,6 +2784,21 @@ if ! $pkg_config --atleast-version=2.38 glib-2.0; then
glib_subprocess=no
fi
+# Silence clang 3.5.0 warnings about glib attribute __alloc_size__ usage
+cat > $TMPC << EOF
+#include <glib.h>
+int main(void) { return 0; }
+EOF
+if ! compile_prog "$glib_cflags -Werror" "$glib_libs" ; then
+ cat > $TMPC << EOF
+ int main(void) { return 0; }
+EOF
+ if compile_prog "-Werror -Wunknown-attributes" ""; then
+ glib_cflags="-Wno-unknown-attributes $glib_cflags"
+ CFLAGS="-Wno-unknown-attributes $CFLAGS"
+ fi
+fi
+
##########################################
# SHA command probe for modules
if test "$modules" = yes; then
--
2.1.0