Re: [PATCH][gdb/testsuite] Fix gdb.dwarf2/dw2-dir-file-name.exp

[Thiago Jung Bauermann via Gdb-patches <gdb-patches@sourceware.org>]

Hello,

will schmidt via Gdb-patches <gdb-patches@sourceware.org> writes:

> On Mon, 2022-08-15 at 09:54 -0700, Carl Love wrote:
>> Tom:
>> 
>> OK, I took a look at how the test used to work and how it is now
>> working and I see what the issue is. 
>> 
>> PowerPC has two entry points, local and global.  The test used to set
>> the breakpoint for the function at the local entry point.  With your
>> changes, the breakpoint is now being set at the global breakpoint
>> which
>> is before the local breakpoint.  The function is actually entered at
>> the local breakpoint thus gdb never "sees" the breakpoint that was
>> set.

[ <snip> ]

>> It looks to me that we need to make sure we set the breakpoint at the
>> local address.  
>> 
>> Off hand, I am not sure how to get your changes to "proc
>> gdb_continue_to_breakpoint" to select the local entry point not the
>> global entry point.  Perhaps Ulrich has some ideas???
>
>
> From a glance that the patch that updated dw2-dir-file-name.exp;
> ( commit cd919f5533cc8aa495acd75a6f059e5fcf2e6af9 )
> the change there was effectively
>
> -       gdb_breakpoint $func
> +       gdb_breakpoint *$func
>
> with assorted regexp changes to match.
>
> The patch description goes into detail, but I interpret the gist of it
> as avoiding the aarch64 architecture prologue skipper, since that
> prologue skipper does something wrong, with entanglements in the line
> table info.
>
> The powerpc prologue skipper (wherever it is) was presumably handling
> the local/global entry points properly.  Since the test now species a
> specific address (*$func), the prologue skipper is no longer involved.
>
> The patch should probably be reverted, but I defer to others if I've
> misunderstood part of this issue.. 

Is it possible to force the compiler to use the global entry point?
Perhaps by calling the function via a function pointer rather than as a
regular function call? That would allow preserving the change to the
testcase and making it work on ppc64le.

-- 
Thiago