On Wed, Aug 27, 2014 at 4:53 PM, Chandler Carruth <chandlerc at google.com> wrote:> > On Wed, Aug 27, 2014 at 4:40 PM, David Blaikie <dblaikie at gmail.com> wrote: > >> DW_AT_frame_base (the location of the frame pointer - is that needed for >> symbolication?) > > > I think this is used by libunwind style stack unwinders in conjunction > with -fomit-frame-pointer >Sounds plausible - any way I might test such a thing? - David -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20140827/0ad3c798/attachment.html>
On Wed, Aug 27, 2014 at 5:03 PM, David Blaikie <dblaikie at gmail.com> wrote:> On Wed, Aug 27, 2014 at 4:53 PM, Chandler Carruth <chandlerc at google.com> > wrote: > >> >> On Wed, Aug 27, 2014 at 4:40 PM, David Blaikie <dblaikie at gmail.com> >> wrote: >> >>> DW_AT_frame_base (the location of the frame pointer - is that needed for >>> symbolication?) >> >> >> I think this is used by libunwind style stack unwinders in conjunction >> with -fomit-frame-pointer >> > > Sounds plausible - any way I might test such a thing? >use gdb or pprof to get a backtrace from abinary build without frame pointers? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20140827/58428cdb/attachment.html>
On Wed, Aug 27, 2014 at 5:04 PM, Chandler Carruth <chandlerc at google.com> wrote:> > On Wed, Aug 27, 2014 at 5:03 PM, David Blaikie <dblaikie at gmail.com> wrote: > >> On Wed, Aug 27, 2014 at 4:53 PM, Chandler Carruth <chandlerc at google.com> >> wrote: >> >>> >>> On Wed, Aug 27, 2014 at 4:40 PM, David Blaikie <dblaikie at gmail.com> >>> wrote: >>> >>>> DW_AT_frame_base (the location of the frame pointer - is that needed >>>> for symbolication?) >>> >>> >>> I think this is used by libunwind style stack unwinders in conjunction >>> with -fomit-frame-pointer >>> >> >> Sounds plausible - any way I might test such a thing? >> > > use gdb or pprof to get a backtrace from abinary build without frame > pointers? >gdb didn't seem to exhibit any difference in behavior when I removed DW_AT_frame_base while compiling my test program (after adding a null dereference to the last call). We'll see, but I may end up removing this until we stumble across a use case for it. - David -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20140828/179f5f2c/attachment.html>