Hi, On some architectures, when given -fstack-protector (which is the default on ubuntu), gcc generates a TLS reference for the stack guard. For instance, on linux x86 with a fairly recent version of glibc:
echo 'void f (void) { volatile char a[8]; a[3]; }' | gcc -S -x c -O2 -fstack-protector - -o - generates a %gs:0x14 reference. In freestanding mode, this poses problem because the target (typically an OS kernel) does not necessarily have TLS. In such case, gcc should default back to referencing __stack_chk_guard. Samuel -- Summary: -fstack-protector shouldn't use TLS in freestanding mode Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: samuel dot thibault at ens-lyon dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29838