https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84761
--- Comment #2 from rguenther at suse dot de <rguenther at suse dot de> --- On Mon, 19 Mar 2018, fw at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84761 > > --- Comment #1 from Florian Weimer <fw at gcc dot gnu.org> --- > This bit needs to change for glibc 2.27 and later: > > #ifdef __i386__ > # define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall)) > #else > # define DL_INTERNAL_FUNCTION > #endif > > We removed the regparm attribute for compatibility with CET. The GCC manual > says that regparm (3) is ABI-compatible on i386, but it really is not. > > We could perhaps add an alias to newer glibcs (including 2.27), so that > libasan > can detect that glibc is more recent and call the function with the right > ABI. > Or expose the information via dlinfo (but the interface is problematic because > it assumes that the static TLS size is fixed—we could eventually switch to a > model where we have a larger reserved region for the initial thread). I think as there are already quite some __GLIBC_PREREQ uses in the sanitizer lib changing the above prototype appropriately would be good enough. Of course exposing the desired information without the need to resort to a private interface would be nice. So sth like Index: libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cc =================================================================== --- libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cc (revision 258641) +++ libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cc (working copy) @@ -152,7 +152,14 @@ bool SanitizerGetThreadName(char *name, static uptr g_tls_size; #ifdef __i386__ +#ifndef __GLIBC_PREREQ +#define __GLIBC_PREREQ(x, y) 0 +#endif +#ifdef SANITIZER_LINUX && __GLIBC_PREREQ(2, 27) +# define DL_INTERNAL_FUNCTION +#else # define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall)) +#endif #else # define DL_INTERNAL_FUNCTION #endif
