On Fri, Dec 15, 2017 at 7:17 AM, Tsimbalist, Igor V <igor.v.tsimbal...@intel.com> wrote: >> -----Original Message----- >> From: Alexandre Oliva [mailto:aol...@redhat.com] >> Sent: Thursday, December 14, 2017 7:37 PM >> To: Tsimbalist, Igor V <igor.v.tsimbal...@intel.com> >> Cc: gcc-patches@gcc.gnu.org >> Subject: Re: [compare-debug] use call loc for nop_endbr >> >> On Dec 14, 2017, "Tsimbalist, Igor V" <igor.v.tsimbal...@intel.com> wrote: >> >> >> Regstrapping with -fcompare-debug on stage3 host and target builds on >> >> x86_64- and i686-linux-gnu; ok to install? >> >> > Ok from me. >> >> Thanks, I went ahead and installed it. >> >> > Am I correct the error you had was related to improper location >> information, >> >> Yeah, only location information. >> >> > I will try to skip NOTE insns only. >> >> You probably want to skip debug insns and notes, too. Actually, IIRC >> you insert these insns after var-tracking, so you probably only have to >> deal with notes. You don't have to, but if bindings are intended to >> take effect right after the call, it would probably be nice if they >> still did so, e.g., even if you happen to single-step out of the call >> and stop at the nop_endbr insn. > Yes, I expect this behavior. > >> BTW, is this the subject of a Cauldron 2017 talk in which I raised an >> issue about PLT entries possibly needing special opcodes to enable them >> to be used as call targets or somesuch? I had initially retracted my >> question, when it was stated that only indirect calls needed special >> treatment, but later I realized that in some cases PLT entries *are* >> used as function addresses even for functions that have their addresses >> taken. Please let me know if you're familiar with the issue and would >> like me to detail the problem. > Please give more info. I do not remember all details but PLT entries > were changes to have endbr instruction (if this is relevant to your question > :). > HJ did this.
PLT is covered. See x86 psABI for CET: https://github.com/hjl-tools/x86-psABI/wiki/X86-psABI -- H.J.
