[compare-debug] use call loc for nop_endbr

[Alexandre Oliva]

On Dec 14, 2017, "Tsimbalist, Igor V" <igor.v.tsimbalist@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.


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.

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer