RedHat 9 _random failure under -pg (was Re: [Python-Dev] Startup time)

[Jeff Epler]

On Tue, May 06, 2003 at 01:36:00PM -0500, Jeff Epler wrote:
> (gdb) run -c "import random"
> Starting program: /usr/src/Python-2.3b1/python -c "import random"
> [New Thread 1074963072 (LWP 28408)]
> 
> Program received signal SIGILL, Illegal instruction.
> [Switching to Thread 1074963072 (LWP 28408)]
> 0x08109aa0 in subtype_getsets_full ()
> (gdb) where
> #0  0x08109aa0 in subtype_getsets_full ()
> #1  0x4001c743 in random_new (type=0x4001c738, args=0x4012c02c, kwds=0x0)
>                at /usr/src/Python-2.3b1/Modules/_randommodule.c:439
> (gdb) ptype subtype_getsets_full
> type = struct PyGetSetDef {
> [...]

gcc is generating plainly bogus code for this simple function
random_new:
00001738 <random_new>:
    1738:       55                      push   %ebp
    1739:       89 e5                   mov    %esp,%ebp
    173b:       56                      push   %esi
    173c:       53                      push   %ebx
    173d:       ff 93 7c 00 00 00       call   *0x7c(%ebx)

(for those of you who don't read x86 assembly, the first 4 functions
are part of a standard function prologue.  The fifth instruction is
a call through a function pointer, but the register's value at this
point is undefined.  This is not the call to type->tp_alloc(), correct
code for that is just below)

Well, this may have been false alarm -- when I removed -pg from OPT in
the Makefile, './python -c "import random"' works.  So this is a problem
only when profiling is enabled.  Is this intended to work?

In any case, the fact that the disassembly is so plainly bogus tends to
imply that this is a gcc bug, not anything that Python can fix.

Jeff