[PATCH 2/2] GCC release 8 support for gcc-plugins

[PATCH 2/2] GCC release 8 support for gcc-plugins

[valdis.kletnieks]

For reasons totally beyond my understanding, gcc 8 changed the
order of two structure member, which leads to an error:

  HOSTCXX -fPIC scripts/gcc-plugins/latent_entropy_plugin.o
scripts/gcc-plugins/latent_entropy_plugin.c:269:1: error: designator order for field 'attribute_spec::affects_type_identity' does not match declaration order in 'attribute_spec'
 };
 ^
make[1]: *** [scripts/Makefile.host:141: scripts/gcc-plugins/latent_entropy_plugin.o] Error 1

Maybe we'll get lucky and they'll undo that change before official release, so all
this ad-crock #ifdef-ery won't be needed.  Do we know any gcc experts to ask?

Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>

--- diff --git a/scripts/gcc-plugins/latent_entropy_plugin.c b/scripts/gcc-plugins/latent_entropy_plugin.c
index 65264960910d..15a6df3592c5 100644
--- a/scripts/gcc-plugins/latent_entropy_plugin.c
+++ b/scripts/gcc-plugins/latent_entropy_plugin.c
@@ -262,10 +262,17 @@ static struct attribute_spec latent_entropy_attr = {
 	.decl_required			= true,
 	.type_required			= false,
 	.function_type_required		= false,
+#if BUILDING_GCC_VERSION >= 8000
+	.affects_type_identity		= false,
 	.handler			= handle_latent_entropy_attribute,
+#else
 #if BUILDING_GCC_VERSION >= 4007
-	.affects_type_identity		= false
-#endif
+	.handler			= handle_latent_entropy_attribute,
+	.affects_type_identity		= false,
+#else
+	.handler			= handle_latent_entropy_attribute,
+#endif /* >= 4007 */
+#endif /* >= 8000 */
 };
 
 static void register_attributes(void *event_data __unused, void *data __unused)
diff --git a/scripts/gcc-plugins/structleak_plugin.c b/scripts/gcc-plugins/structleak_plugin.c
index 3f8dd4868178..f700bc059050 100644
--- a/scripts/gcc-plugins/structleak_plugin.c
+++ b/scripts/gcc-plugins/structleak_plugin.c
@@ -64,10 +64,17 @@ static struct attribute_spec user_attr = {
 	.decl_required		= false,
 	.type_required		= false,
 	.function_type_required	= false,
-	.handler		= handle_user_attribute,
+#if BUILDING_GCC_VERSION >= 8000
+	.affects_type_identity		= false,
+	.handler			= handle_latent_entropy_attribute,
+#else
 #if BUILDING_GCC_VERSION >= 4007
-	.affects_type_identity	= true
-#endif
+	.handler			= handle_latent_entropy_attribute,
+	.affects_type_identity		= false,
+#else
+	.handler			= handle_latent_entropy_attribute,
+#endif /* >= 4007 */
+#endif /* >= 8000 */
 };
 
 static void register_attributes(void *event_data, void *data)
diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
index 0073af326449..1dafa102a907 100644
--- a/scripts/gcc-plugins/randomize_layout_plugin.c
+++ b/scripts/gcc-plugins/randomize_layout_plugin.c
@@ -589,10 +589,17 @@ static struct attribute_spec randomize_layout_attr = {
 	// need type declaration
 	.type_required	= true,
 	.function_type_required = false,
-	.handler		= handle_randomize_layout_attr,
+#if BUILDING_GCC_VERSION >= 8000
+	.affects_type_identity		= false,
+	.handler			= handle_latent_entropy_attribute,
+#else
 #if BUILDING_GCC_VERSION >= 4007
-	.affects_type_identity  = true
-#endif
+	.handler			= handle_latent_entropy_attribute,
+	.affects_type_identity		= false,
+#else
+	.handler			= handle_latent_entropy_attribute,
+#endif /* >= 4007 */
+#endif /* >= 8000 */
 };
 
 static struct attribute_spec no_randomize_layout_attr = {
@@ -604,10 +611,17 @@ static struct attribute_spec no_randomize_layout_attr = {
 	// need type declaration
 	.type_required	= true,
 	.function_type_required = false,
-	.handler		= handle_randomize_layout_attr,
+#if BUILDING_GCC_VERSION >= 8000
+	.affects_type_identity		= false,
+	.handler			= handle_latent_entropy_attribute,
+#else
 #if BUILDING_GCC_VERSION >= 4007
-	.affects_type_identity  = true
-#endif
+	.handler			= handle_latent_entropy_attribute,
+	.affects_type_identity		= false,
+#else
+	.handler			= handle_latent_entropy_attribute,
+#endif /* >= 4007 */
+#endif /* >= 8000 */
 };
 
 static struct attribute_spec randomize_considered_attr = {
@@ -619,10 +633,17 @@ static struct attribute_spec randomize_considered_attr = {
 	// need type declaration
 	.type_required	= true,
 	.function_type_required = false,
-	.handler		= handle_randomize_considered_attr,
+#if BUILDING_GCC_VERSION >= 8000
+	.affects_type_identity		= false,
+	.handler			= handle_latent_entropy_attribute,
+#else
 #if BUILDING_GCC_VERSION >= 4007
-	.affects_type_identity  = false
-#endif
+	.handler			= handle_latent_entropy_attribute,
+	.affects_type_identity		= false,
+#else
+	.handler			= handle_latent_entropy_attribute,
+#endif /* >= 4007 */
+#endif /* >= 8000 */
 };
 
 static struct attribute_spec randomize_performed_attr = {
@@ -634,10 +655,17 @@ static struct attribute_spec randomize_performed_attr = {
 	// need type declaration
 	.type_required	= true,
 	.function_type_required = false,
-	.handler		= handle_randomize_performed_attr,
+#if BUILDING_GCC_VERSION >= 8000
+	.affects_type_identity		= false,
+	.handler			= handle_latent_entropy_attribute,
+#else
 #if BUILDING_GCC_VERSION >= 4007
-	.affects_type_identity  = false
-#endif
+	.handler			= handle_latent_entropy_attribute,
+	.affects_type_identity		= false,
+#else
+	.handler			= handle_latent_entropy_attribute,
+#endif /* >= 4007 */
+#endif /* >= 8000 */
 };
 
 static void register_attributes(void *event_data, void *data)

Re: [PATCH 2/2] GCC release 8 support for gcc-plugins

[Kees Cook]

On Mon, Feb 5, 2018 at 4:34 AM,  <valdis.kletnieks@vt.edu> wrote:
> For reasons totally beyond my understanding, gcc 8 changed the
> order of two structure member, which leads to an error:
>
>   HOSTCXX -fPIC scripts/gcc-plugins/latent_entropy_plugin.o
> scripts/gcc-plugins/latent_entropy_plugin.c:269:1: error: designator order for field 'attribute_spec::affects_type_identity' does not match declaration order in 'attribute_spec'
>  };
>  ^

FWIW, my gcc 8 snapshot reports:

scripts/gcc-plugins/latent_entropy_plugin.c:269:1: sorry,
unimplemented: non-trivial designated initializers not supported
 };
 ^

But yeah, it seems that initializer _order_ matters here. Uuuugh.

I think instead of static initializers, we can just move this into the
register function, then order won't matter again. e.g.:


diff --git a/scripts/gcc-plugins/latent_entropy_plugin.c
b/scripts/gcc-plugins/latent_entropy_plugin.c
index 65264960910d..6836b8cd9fc4 100644
--- a/scripts/gcc-plugins/latent_entropy_plugin.c
+++ b/scripts/gcc-plugins/latent_entropy_plugin.c
@@ -255,21 +255,21 @@ static tree handle_latent_entropy_attribute(tree
*node, tree name,
        return NULL_TREE;
 }

-static struct attribute_spec latent_entropy_attr = {
-       .name                           = "latent_entropy",
-       .min_length                     = 0,
-       .max_length                     = 0,
-       .decl_required                  = true,
-       .type_required                  = false,
-       .function_type_required         = false,
-       .handler                        = handle_latent_entropy_attribute,
-#if BUILDING_GCC_VERSION >= 4007
-       .affects_type_identity          = false
-#endif
-};
+static struct attribute_spec latent_entropy_attr;

 static void register_attributes(void *event_data __unused, void *data __unused)
 {
+       latent_entropy_attr.name                        = "latent_entropy";
+       latent_entropy_attr.min_length                  = 0;
+       latent_entropy_attr.max_length                  = 0;
+       latent_entropy_attr.decl_required               = true;
+       latent_entropy_attr.type_required               = false;
+       latent_entropy_attr.function_type_required      = false;
+       latent_entropy_attr.handler     = handle_latent_entropy_attribute;
+#if BUILDING_GCC_VERSION >= 4007
+       latent_entropy_attr.affects_type_identity       = false;
+#endif
+
        register_attribute(&latent_entropy_attr);
 }

(pardon whitespace damage...)

-Kees

-- 
Kees Cook
Pixel Security

Re: [PATCH 2/2] GCC release 8 support for gcc-plugins

[Christoph Hellwig]

On Sun, Feb 04, 2018 at 12:34:38PM -0500, valdis.kletnieks@vt.edu wrote:
> For reasons totally beyond my understanding, gcc 8 changed the
> order of two structure member, which leads to an error:

I'm a little late on this, but isn't the whole point of C99 initializers
that field order should not matter at all?

Re: [PATCH 2/2] GCC release 8 support for gcc-plugins

[Kees Cook]

On Tue, Feb 13, 2018 at 6:56 AM, Christoph Hellwig <hch@infradead.org> wrote:
> On Sun, Feb 04, 2018 at 12:34:38PM -0500, valdis.kletnieks@vt.edu wrote:
>> For reasons totally beyond my understanding, gcc 8 changed the
>> order of two structure member, which leads to an error:
>
> I'm a little late on this, but isn't the whole point of C99 initializers
> that field order should not matter at all?

For C99, this is true. The plugins are built differently and follow
C++ conventions, which, for reasons I cannot understand, are ordered.
:( Regardless, the fix actually results in fewer lines of code, so
this is fine.

-Kees

-- 
Kees Cook
Pixel Security