[libvirt] [PATCH 2/2] build: add GCC 6.0 -Wlogical-op workaround
Pavel Hrdina
phrdina at redhat.com
Sun Apr 10 16:37:59 UTC 2016
fdstream.c: In function 'virFDStreamWrite':
fdstream.c:390:29: error: logical 'or' of equal expressions [-Werror=logical-op]
if (errno == EAGAIN || errno == EWOULDBLOCK) {
^~
Fedora rawhide now uses gcc 6.0 and there is a bug with -Wlogical-op
producing false warnings.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69602
Use GCC pragma push/pop and ignore -Wlogical-op for GCC that supports
push/pop pragma and also has this bug.
Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
---
m4/virt-compile-warnings.m4 | 20 ++++++++++++++++++++
src/fdstream.c | 4 ++++
src/internal.h | 12 ++++++++++++
src/rpc/virnetsshsession.c | 6 ++++++
src/security/security_selinux.c | 2 ++
5 files changed, 44 insertions(+)
diff --git a/m4/virt-compile-warnings.m4 b/m4/virt-compile-warnings.m4
index 1b0a2cf..eb689e2 100644
--- a/m4/virt-compile-warnings.m4
+++ b/m4/virt-compile-warnings.m4
@@ -117,6 +117,20 @@ AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[
[lv_cv_gcc_wlogical_op_broken=yes])
CFLAGS="$save_CFLAGS"])
+ AC_CACHE_CHECK([whether gcc gives bogus warnings for -Wlogical-op],
+ [lv_cv_gcc_wlogical_op_equal_expr_broken], [
+ save_CFLAGS="$CFLAGS"
+ CFLAGS="-O2 -Wlogical-op -Werror"
+ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+ #define TEST1 1
+ #define TEST2 TEST1
+ ]], [[
+ int test = 0;
+ return test == TEST1 || test == TEST2;]])],
+ [lv_cv_gcc_wlogical_op_equal_expr_broken=no],
+ [lv_cv_gcc_wlogical_op_equal_expr_broken=yes])
+ CFLAGS="$save_CFLAGS"])
+
# We might fundamentally need some of these disabled forever, but
# ideally we'd turn many of them on
dontwarn="$dontwarn -Wfloat-equal"
@@ -239,4 +253,10 @@ AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[
AC_DEFINE_UNQUOTED([BROKEN_GCC_WLOGICALOP_STRCHR], 1,
[Define to 1 if gcc -Wlogical-op reports false positives on strchr])
fi
+
+ if test "$gl_cv_warn_c__Wlogical_op" = yes &&
+ test "$lv_cv_gcc_wlogical_op_equal_expr_broken" = yes; then
+ AC_DEFINE_UNQUOTED([BROKEN_GCC_WLOGICALOP_EQUAL_EXPR], 1,
+ [Define to 1 if gcc -Wlogical-op reports false positive 'or' equal expr])
+ fi
])
diff --git a/src/fdstream.c b/src/fdstream.c
index a85cf9d..ef118b5 100644
--- a/src/fdstream.c
+++ b/src/fdstream.c
@@ -387,7 +387,9 @@ static int virFDStreamWrite(virStreamPtr st, const char *bytes, size_t nbytes)
retry:
ret = write(fdst->fd, bytes, nbytes);
if (ret < 0) {
+ VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR
if (errno == EAGAIN || errno == EWOULDBLOCK) {
+ VIR_WARNINGS_RESET
ret = -2;
} else if (errno == EINTR) {
goto retry;
@@ -437,7 +439,9 @@ static int virFDStreamRead(virStreamPtr st, char *bytes, size_t nbytes)
retry:
ret = read(fdst->fd, bytes, nbytes);
if (ret < 0) {
+ VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR
if (errno == EAGAIN || errno == EWOULDBLOCK) {
+ VIR_WARNINGS_RESET
ret = -2;
} else if (errno == EINTR) {
goto retry;
diff --git a/src/internal.h b/src/internal.h
index bc3126f..3843d92 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -245,11 +245,23 @@
_Pragma ("GCC diagnostic push")
# endif
+/* Workaround bogus GCC 6.0 for logical 'or' equal expression warnings.
+ * (GCC bz 69602) */
+# if BROKEN_GCC_WLOGICALOP_EQUAL_EXPR
+# define VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR \
+ _Pragma ("GCC diagnostic push") \
+ _Pragma ("GCC diagnostic ignored \"-Wlogical-op\"")
+# else
+# define VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR \
+ _Pragma ("GCC diagnostic push")
+# endif
+
# define VIR_WARNINGS_RESET \
_Pragma ("GCC diagnostic pop")
# else
# define VIR_WARNINGS_NO_CAST_ALIGN
# define VIR_WARNINGS_NO_PRINTF
+# define VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR
# define VIR_WARNINGS_RESET
# endif
diff --git a/src/rpc/virnetsshsession.c b/src/rpc/virnetsshsession.c
index 406a831..e742175 100644
--- a/src/rpc/virnetsshsession.c
+++ b/src/rpc/virnetsshsession.c
@@ -545,9 +545,11 @@ virNetSSHAuthenticateAgent(virNetSSHSessionPtr sess,
agent_identity)))
return 0; /* key accepted */
+ VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR
if (ret != LIBSSH2_ERROR_AUTHENTICATION_FAILED &&
ret != LIBSSH2_ERROR_PUBLICKEY_UNRECOGNIZED &&
ret != LIBSSH2_ERROR_PUBLICKEY_UNVERIFIED) {
+ VIR_WARNINGS_RESET
libssh2_session_last_error(sess->session, &errmsg, NULL, 0);
virReportError(VIR_ERR_AUTH_FAILED,
_("failed to authenticate using SSH agent: %s"),
@@ -605,9 +607,11 @@ virNetSSHAuthenticatePrivkey(virNetSSHSessionPtr sess,
priv->password)) == 0)
return 0; /* success */
+ VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR
if (priv->password ||
ret == LIBSSH2_ERROR_PUBLICKEY_UNRECOGNIZED ||
ret == LIBSSH2_ERROR_AUTHENTICATION_FAILED) {
+ VIR_WARNINGS_RESET
libssh2_session_last_error(sess->session, &errmsg, NULL, 0);
virReportError(VIR_ERR_AUTH_FAILED,
_("authentication with private key '%s' "
@@ -673,11 +677,13 @@ virNetSSHAuthenticatePrivkey(virNetSSHSessionPtr sess,
"has failed: %s"),
priv->filename, errmsg);
+ VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR
if (ret == LIBSSH2_ERROR_PUBLICKEY_UNRECOGNIZED ||
ret == LIBSSH2_ERROR_AUTHENTICATION_FAILED)
return 1;
else
return -1;
+ VIR_WARNINGS_RESET
}
return 0;
diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
index 26d95d1..04760a1 100644
--- a/src/security/security_selinux.c
+++ b/src/security/security_selinux.c
@@ -911,8 +911,10 @@ virSecuritySELinuxSetFileconHelper(const char *path, char *tcon,
* hopefully sets one of the necessary SELinux virt_use_{nfs,usb,pci}
* boolean tunables to allow it ...
*/
+ VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR
if (setfilecon_errno != EOPNOTSUPP && setfilecon_errno != ENOTSUP &&
setfilecon_errno != EROFS) {
+ VIR_WARNINGS_RESET
virReportSystemError(setfilecon_errno,
_("unable to set security context '%s' on '%s'"),
tcon, path);
--
2.8.1
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