Re: installing graphviz from pkgsrc on NetBSD/macppc 9.1

[Havard Eidnes <he%NetBSD.org@localhost>]

> It turns out that pcre has configure code to explicitly remove
> any user-supplied "-g" option, which makes debugging more
> difficult.  Getting a "-g" through to the copiler turns out to
> not exactly be straight-forward (I've tried tweaking configure to
> do so, so far unsuccessfully), so I'm stuck there at the moment.

I managed to force pcre to build with the "-g" option.  However,
that also didn't really reveal the problem; the program crashes
on an instruction where there is no debug info.

After some assistance from fellow NetBSD developers, it turns out
it's crashing in

00000000 <.text.startup>:
   0:   94 21 ff e0     stwu    r1,-32(r1)
   4:   7c 08 02 a6     mflr    r0
   8:   42 9f 00 05     bcl     20,4*cr7+so,c <.text.startup+0xc>
   c:   93 c1 00 18     stw     r30,24(r1)
  10:   7f c8 02 a6     mflr    r30
  14:   3f de 00 00     addis   r30,r30,0
                        16: R_PPC_REL16_HA      .got2+0x800a
  18:   90 01 00 24     stw     r0,36(r1)
  1c:   3b de 00 00     addi    r30,r30,0
                        1e: R_PPC_REL16_LO      .got2+0x8012
  20:   80 9e 80 04     lwz     r4,-32764(r30)
>>24:   89 24 00 00     lbz     r9,0(r4)
  28:   2f 89 00 00     cmpwi   cr7,r9,0
  2c:   40 9e 00 58     bne     cr7,84 <.text.startup+0x84>
  30:   81 3e 80 08     lwz     r9,-32760(r30)
  34:   39 40 00 01     li      r10,1
  38:   93 a1 00 14     stw     r29,20(r1)
  3c:   2f 89 00 00     cmpwi   cr7,r9,0
  40:   93 e1 00 1c     stw     r31,28(r1)
  44:   99 44 00 00     stb     r10,0(r4)
  48:   41 9e 00 10     beq     cr7,58 <.text.startup+0x58>

(this is "objdump -dr" of /usr/lib/crtbgeginS.o).

This code comes from /usr/src/lib/csu/common/crtbegin.c, the
function __do_global_ctors_aux(), and it appears that it's trying
to load the static variable __initialized; the store of 1 into it
is happening via the instructions at 34 and 44.

Now, it's evident from the debugger that r4 ends up as 0, causing
a null pointer de-reference and a SEGV.

I have not yet been able to figure out exactly *why* this code
fails in this manner, though.

Regards,

- Håvard