tdep/2016: powerpc64-linux r2 set incorrectly on inferior function calls

[amodra at bigpond dot net dot au]

>Number:         2016
>Category:       tdep
>Synopsis:       powerpc64-linux r2 set incorrectly on inferior function calls
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Sep 26 10:48:06 UTC 2005
>Closed-Date:
>Last-Modified:
>Originator:     Alan Modra
>Release:        gdb 6
>Organization:
>Environment:

>Description:
powerpc64-linux ld supports generation of executables with multiple toc sections.  If such an application is stopped in a function, and gdb makes an inferior function call to a function which uses a different toc value, then the wrong value will be used.  The correct toc pointer value can be found in the called function's OPD entry (where powerpc64-linux function pointers point).
>How-To-Repeat:
eg. on debugging powerpc64-linux gcc testsuite failure..

Breakpoint 1, fancy_abort (file=0x1058d0d0 "/src/gcc-current/gcc/expr.c", 
    line=3929, function=0x1058d390 "expand_assignment")
    at /src/gcc-current/gcc/diagnostic.c:590
(gdb) up
#1  0x00000000101b8d38 in expand_assignment (to=0x8000313f08, 
    from=0x8000324370) at /src/gcc-current/gcc/expr.c:3929
(gdb) p debug_tree (to)

Program received signal SIGILL, Illegal instruction.
0x0000000010677fbc in __FUNCTION__.16129 ()
The program being debugged was signaled while in a function called from GDB.
GDB remains in the frame where the signal was received.
To change this behavior use "set unwindonsignal on"
Evaluation of the expression containing the function (debug_tree) will be abandoned.
(gdb) 
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: