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[PING] Re: [PATCH v2] Define an error function in the PPC simulator library.
- From: John Baldwin <jhb at freebsd dot org>
- To: gdb-patches at sourceware dot org
- Cc: Luis Machado <lgustavo at codesourcery dot com>
- Date: Fri, 19 May 2017 09:27:01 -0700
- Subject: [PING] Re: [PATCH v2] Define an error function in the PPC simulator library.
- Authentication-results: sourceware.org; auth=none
- References: <20170405163332.82109-1-jhb@FreeBSD.org> <2136315.0HrDL9yZYa@ralph.baldwin.cx> <2947645.NYcQbnJ46M@ralph.baldwin.cx>
On Friday, May 05, 2017 12:22:43 PM John Baldwin wrote:
> On Thursday, April 13, 2017 10:18:14 AM John Baldwin wrote:
> > On Thursday, April 13, 2017 08:25:27 AM Luis Machado wrote:
> > > On 04/05/2017 11:33 AM, John Baldwin wrote:
> > > > Previously this used the error function from GDB directly when linked
> > > > against GDB instead of the error method in the host callbacks
> > > > structure. This was exposed via a link error when GDB was converted
> > > > to C++. The error function invokes the error callback similar to
> > > > sim_io_error.
> > > >
> > >
> > > There is another implementation of error (...) in sim/ppc/main.c and
> > > sim/ppc/misc.c. Should those be kept as is or should we only use the new
> > > function you're providing?
> > My understanding is that they should be kept as-is. This file is only used
> > when linking the library against GDB (and actually, rereading the log message,
> > I should reword the opening sentence to make this clearer). sim-calls.o isn't
> > included in the actual library. Each consumer of the library is required
> > to export a couple of symbols that libsim.a uses including "error". The dgen,
> > igen, tmp-filter, tmp-ld-decode, tmp-ld-cache, and tmp-ld-insn programs use
> > the functions from misc.c. psim uses the functions from main.c, and
> > GDB uses the functions from sim-calls.o. glibc includes a global function
> > called 'error' that libsim.a is linking against when linked into GDB on
> > Linux which is why it doesn't fail to link on Linux (but if it ever needs
> > to raise an error it probably blows up as error(3) doesn't have the same
> > calling convention).
> > > Also, i don't see error being implemented in the other sim backends. I
> > > wonder if we should just use whatever is available (sim_io_error?)
> > > instead of supplying our own ppc-specific version?
> > Other sims don't use an "error" function (ppc seems to be special in this
> > case). I think Pedro took a stab at replacing "error" (there's a thread
> > with the subject "gdb-7.12-powerpc-rtems4.12-gdb does not build on FreeBSD"
> > on gdb@) but thought this approach was simpler (and could also be merged
> > to 7.12 though that may be OBE by now).
This does fix a PR, is a regression in 7.12, and is relatively small, so I
think it's a candidate for 8.0 if accepted.