From: Pavel Hrdina <phrdina@redhat.com>

Date: Sun, 10 Apr 2016 18:22:20 +0200

Subject: [PATCH] build: add GCC 6.0 -Wlogical-op workaround

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@redhat.com>

(cherry picked from commit d713a6b120904c488170e7920c482b2fade70ae1)

---

 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 35cc6d4..926e990 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);