Hello, A number of compilers claim to be GCC, without actually being GCC. This has come to a point where they can hardly be distinguished–until one actually tries to use them.
I had the following macro to determine whether plug-in support is available: https://gforge.inria.fr/scm/viewvc.php/trunk/m4/gcc.m4?view=markup&revision=5169&root=starpu&pathrev=5202 The macro is fairly elaborate. Yet, ICC 12.0.1 and Clang 3.4 both pass the test, because: - They support ‘--version’; - They define ‘__GNUC__’, which defeats Autoconf’s ‘_AC_LANG_COMPILER_GNU’. - They support ‘-print-file-name’, and have ‘-print-file-name=plugin’ return GCC’s (!) plug-in header directory. To that end, ICC simply runs ‘gcc -print-file-name=plugin’, while Clang appears to be doing some guesswork. It turns out that ICC manages to build a working GCC plug-in, so after all, it may be “entitled” to define ‘__GNUC__’, in a broad sense. Conversely, Clang doesn’t support several GNU extensions, such as nested functions, so it quickly fails to compile code. Based on that, I modified my feature test like this: https://gforge.inria.fr/scm/viewvc.php/trunk/m4/gcc.m4?root=starpu&r1=5169&r2=5203 I don’t see what can be done on “our” side (perhaps Autoconf’s feature test could be strengthened, but how?), but I wanted to document this state of affairs. Thanks, Ludo’.
