MPIR_PROCDESC is not visible in non-debug builds

[jjhursey]

• Impacts master, v3.0.x, and v3.1.x. The v2.x and v2.0.x series do not have this problem.
• Must be built with --disable-debug.

Consider the following gdb script that we will run against an mpirun launching an MPI application.

shell$ cat gdb-test-cmd.txt 
echo MPIR_debug_state\n
p MPIR_debug_state

echo MPIR_proctable_size\n
p MPIR_proctable_size

echo MPIR_proctable (pointer)\n
p MPIR_proctable

echo MPIR_proctable (type info)\n
ptype MPIR_proctable

echo MPIR_proctable (contents)\n
p *MPIR_proctable@MPIR_proctable_size

On master with a --enable-debug build you can see the expected:

shell$ gdb --batch -x gdb-test-cmd.txt --pid `ps aux | grep mpirun | grep -v grep | awk '{print $2}'`[New LWP 92532]
[New LWP 92531]
[New LWP 92530]
[New LWP 92529]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
0x00003fff953dd5d8 in poll () from /lib64/libc.so.6
MPIR_debug_state
$1 = 1
MPIR_proctable_size
$2 = 2
MPIR_proctable (pointer)
$3 = (struct MPIR_PROCDESC *) 0x100081b59d0
MPIR_proctable (type info)
type = struct MPIR_PROCDESC {
    char *host_name;
    char *executable_name;
    int pid;
} *
MPIR_proctable (contents)
$4 = {{
    host_name = 0x100081b6a40 "n01", 
    executable_name = 0x100081b45b0 "/home/jjhursey/./hello_c", 
    pid = 92533
  }, {
    host_name = 0x100081b7bd0 "n01", 
    executable_name = 0x100080107f0 "/home/jjhursey/./hello_c", 
    pid = 92534
  }}

On master with a --disable-debug build the MPIR_PROCDESC structure is obscured so we cannot read the MPIR_proctable

shell$ gdb --batch -x gdb-test-cmd.txt --pid `ps aux | grep mpirun | grep -v grep | awk '{print $2}'`[New LWP 92409]
[New LWP 92408]
[New LWP 92407]
[New LWP 92406]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
0x00003fff799fd5d8 in poll () from /lib64/libc.so.6
MPIR_debug_state
$1 = 1
MPIR_proctable_size
$2 = 2
MPIR_proctable (pointer)
$3 = 635592864
MPIR_proctable (type info)
type = <data variable, no debug info>
MPIR_proctable (contents)
gdb-test-cmd.txt:14: Error in sourced command file:
Cannot access memory at address 0x25e260a0