On Tue, May 19, 2009 at 11:40:54AM -0400, Tom Horsley wrote: > I was just wondering if there is anyone out there in redhat > land who can shed more light on the use of dwarf register 16 > for a virtual "return address" in .eh_frame info, probably > hand generated .eh_frame info in the vicinity of the > pthreads library mutex locking code. > Does http://sources.redhat.com/ml/libc-hacker/2006-09/msg00003.html http://gcc.gnu.org/ml/gcc-patches/2006-03/msg00208.html shed some light? The lock spinning pads are in inline asm in separate subsections (as they are unlikely) and at least before GCC started using .cfi_* directives for eh it was impossible to write inline assembly with code in separate sections/subsections that preserved usable unwind info. The GCC patch as examples in the testcase contains both older version which disassembled the instructions in the pad and computed virtual return address to the spot that branched to the pad (and pad branched to at the end) and the actually used version. Jakub -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
