Re: [PATCH] gdb: Remove support for old mangling schemes

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2019-01-08 22:38, Eli Zaretskii wrote:
>> From: Simon Marchi <simon.marchi@ericsson.com>
>> CC: Simon Marchi <simon.marchi@ericsson.com>
>> Date: Tue, 8 Jan 2019 23:22:22 +0000
>> 
>> An upcoming sync with gcc's libiberty [1] will remove support for old
>> mangling schemes (GNU v2, Lucid, ARM, HP and EDG).  It will remove the
>> cplus_demangle_opname function, so we need to get rid of its usages in
>> GDB (it's a GNU v2 specific function).
> 
> This would mean new GDB releases will not be able to debug old
> programs, is that right?  If so, perhaps we should instead keep our
> local version of the relative functions, so that GDB will not regress
> in that way.  Our considerations in this matter are different from
> those of GCC.

We're talking about really old programs here.  IIUC, the GNU v2 mangling 
was used in the GCC 2.95 era, which is around 2002.  I think it's fine 
to drop support for this.  If you had a system from that era, you would 
have a hard time compiling today's GDB on it.  And even if you just had 
an old binary on a recent systems, well the older GDB releases are 
always available.  I don't think it's worth our time to keep 
compatibility with that.  Just testing it would probably be a nightmare.

I don't know much about the other mangling schemes, but I assume they 
are equally ancient.  Maybe somebody else can give more info about them.

Simon