ppc64 regression: [PATCH 1/2] Fix "list ambiguous_variable"

[Jan Kratochvil <jan.kratochvil@redhat.com>]

On Mon, 16 Oct 2017 17:03:18 +0200, Simon Marchi wrote:
> The buildbot shows some failures on ppc64be:
> 
> PASS -> FAIL: gdb.base/dbx.exp: whereis my_list
> PASS -> FAIL: gdb.mi/gdb669.exp: -thread-list-ids
> PASS -> FAIL: gdb.mi/gdb669.exp: finding MI result string
> PASS -> FAIL: gdb.mi/gdb669.exp: finding number of threads in MI output
> 
> I tested on gcc110, and bisect points to this patch here (for both tests).
> A symptom of the problem is that "break main" generates two locations.
> 
> Before (at e5f25bc5^):
> 
> (gdb) b main
> Breakpoint 1 at 0x10000560: file test.c, line 3.
> (gdb) info breakpoints
> Num     Type           Disp Enb Address            What
> 1       breakpoint     keep y   0x0000000010000560 in main at test.c:3
> 
> After (at e5f25bc5)
> 
> (gdb) b main
> Breakpoint 1 at 0x10000560: main. (2 locations)
> (gdb) info breakpoints
> Num     Type           Disp Enb Address            What
> 1       breakpoint     keep y   <MULTIPLE>
> 1.1                         y     0x0000000010000560 in main at test.c:3
> 1.2                         y     0x0000000010020078 <main>

I have also hit this regression now on RHEL-7.5pre ppc64:

e5f25bc5d6dba5a5c4dd36e08afd57e918c63dea is the first bad commit
commit e5f25bc5d6dba5a5c4dd36e08afd57e918c63dea
Author: Pedro Alves <palves@redhat.com>
Date:   Wed Sep 20 16:12:54 2017 +0100
    Fix "list ambiguous_variable"

echo 'main(){}'|gcc -g -x c -;./gdb -batch ./a.out -ex start
	Temporary breakpoint 1 at 0x10000560: file <stdin>, line 1.
	Temporary breakpoint 1, main () at <stdin>:1
	1       <stdin>: No such file or directory.
->
	Temporary breakpoint 1 at 0x10000560: main. (2 locations)
	Program received signal SIGSEGV, Segmentation fault.
	0x7d82100810000554 in ?? ()


Jan