Re: gdb unable to print fn argument correctly

[Manoj Iyer <manjo@austin.ibm.com>]

> Check what instruction ($pc) GDB has stopped on.  The debug info is
> valid only at or after 0x10000458.  What does the line table look like?
>
> > ==== Disassembly of void fn3(double c){} =======================
> > fn3()
> > [5]     10000448:   94 21 ff e0   stwu       r1, -32(r1)
> >         1000044c:   93 e1 00 1c   stw        r31, 28(r1)
> >         10000450:   7c 3f 0b 78   mr         r31, r1
> >         10000454:   d8 3f 00 08   stfd       fr1, 8(r31)
> >         10000458:   81 61 00 00   lwz        r11, 0(r1)
> >         1000045c:   83 eb ff fc   lwz        r31, -4(r11)
> >         10000460:   7d 61 5b 78   mr         r1, r11
> >         10000464:   4e 80 00 20   blr
> > ==================================================================
>

GDB stopped on the instruction at 0x...10000544, which is 10000544:   d8
3f 00 70     stfd    f1,112(r31).

Here is what my line table looks like:

================ line table =================
Compilation Unit Number 6:
        length 58, version 2, prolog length 27
        Minimum instruction length: 4
        Default is statement: 1
        Line base: -5
        Line range: 14
        Opcode base: 10
        Opcode lengths: 0 1 1 1 1 0 0 0 1

        Include Directories:

        File Names Table:
        File Directory    Last Modified        Size  Name
           1     0     Dec 31 18:00:00 1969       0  test1.c

              Line Column   Address  File
              ---- ------   -------  ----
           1     3    0   0x100004e4 test1.c
           2     4    0   0x10000510 test1.c
           3     5    0   0x10000538 test1.c
           4     9    0   0x10000560 test1.c
           5    10    0   0x10000574 test1.c
           6    11    0   0x1000057c test1.c
           7    12    0   0x10000588 test1.c
           8    13    0   0x10000594 test1.c
           9    14    0   0x10000598 test1.c

================== enf of line table ===========================



================ GDB output ====================================
(gdb) br main
Breakpoint 1 at 0x10000574: file test1.c, line 10.
(gdb) br fn3
Breakpoint 2 at 0x10000544: file test1.c, line 5.
(gdb) r
Starting program: /tmp/test1.gdb

Breakpoint 1, main () at test1.c:10
10          fn1(1234);
(gdb) c
Continuing.

Breakpoint 2, 0x0000000010000544 in fn3 (c=6.0995758190771502e-316)
    at test1.c:5
5       void fn3(double c){}
================================================================

=========== disassembly of fn3 =================================
0000000010000538 <.fn3>:
    10000538:   fb e1 ff f8     std     r31,-8(r1)
    1000053c:   f8 21 ff c1     stdu    r1,-64(r1)
    10000540:   7c 3f 0b 78     mr      r31,r1
    10000544:   d8 3f 00 70     stfd    f1,112(r31)
    10000548:   e8 21 00 00     ld      r1,0(r1)
    1000054c:   eb e1 ff f8     ld      r31,-8(r1)
    10000550:   4e 80 00 20     blr
        ...
    1000055c:   80 01 00 01     lwz     r0,1(r1)
=======================================================