[Bug plugins/61934] New: C++11 generalised attributes and plugins don't work

["tom.k.cook at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61934

            Bug ID: 61934
           Summary: C++11 generalised attributes and plugins don't work
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: plugins
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tom.k.cook at gmail dot com

Created attachment 33195
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33195&action=edit
Pre-processed GCC plugin defining the Test attribute.

Defining a custom attribute using the register_attribute function does not
interact correctly with C++11 attributes.  The attached, preprocessed plugin
source (my_plugin.ii) is compiled with the following command-line:

g++ -fPIC -fno-rtti -std=c++11 -save-temps
-I/usr/lib/gcc/x86_64-linux-gnu/4.8/plugin/include -c my_plugin.cc -o
my_plugin.o
g++ -fPIC -fno-rtti -std=c++11 -save-temps -shared my_plugin.o -o my_plugin.so

The plugin is tested with this source:

$ cat test.cc
void __attribute__((Test)) Foo() {
}

[[Test]] void Bar() {
}

which is compiled with this command-line:

g++ -fPIC -fno-rtti -std=c++11 -save-temps -fplugin=./my_plugin.so -c test.cc
-o test.o

The first function definition is compiled without errors or warnings but the
second function definition gives this warning:

test.cc:4:19: warning: âTestâ attribute directive ignored [-Wattributes]
 [[Test]] void Bar() {
                   ^
The two are supposed to be equivalent.  Changing the plugin to register a
scoped attribute using register_scoped_attributes works correctly.

The GCC information given below is from version 4.8, but I have tested this
with the GCC 4.9.1 build available in the Ubuntu toolchains PPA with the same
result.

Output of g++ -v:

Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.8/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.2-19ubuntu1'
--with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs
--enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.8 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap
--enable-plugin --with-system-zlib --disable-browser-plugin
--enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --with-tune=generic
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)