Re: Elfutils segfault on IA64

On Wed, Oct 2, 2013 at 1:51 PM, Kurt Roeckx <kurt@roeckx.be> wrote:

On Wed, Oct 02, 2013 at 01:43:56PM -0500, Patrick Baggett wrote:
> I set the breakpoint, and it is called as you expected:
> (gdb) bt
> #0 ppc_register_info (ebl=0x6000000000004120, regno=-1, name=0x0,
> namelen=0, prefix=0x0, setname=0x0, bits=0x0, type=0x0) at ppc_regs.c:45

It's for the regno=1 case that I want to know that it properly
sets everything. Can you watch what happens?

Breakpoint 1, ppc_register_info (ebl=0x6000000000004120, regno=-1, name=0x0, namelen=0, prefix=0x0, setname=0x0, bits=0x0, type=0x0) at ppc_regs.c:45

45 if (name == NULL)

(gdb) continue

Continuing.

Breakpoint 1, ppc_register_info (ebl=0x6000000000004120, regno=0, name=0x60000fffffffb328 "\355\377", namelen=32, prefix=0x60000fffffffb318, setname=0x60000fffffffb320, bits=0x60000fffffffb314, type=0x60000fffffffb310) at ppc_regs.c:45

45 if (name == NULL)

(gdb) continue

Continuing.

integer reg0 (r0): undefined

Breakpoint 1, ppc_register_info (ebl=0x6000000000004120, regno=1, name=0x60000fffffffb328 "r0", namelen=32, prefix=0x60000fffffffb318, setname=0x60000fffffffb320, bits=0x60000fffffffb314, type=0x60000fffffffb310) at ppc_regs.c:45

45 if (name == NULL)

(gdb) bt

#0 ppc_register_info (ebl=0x6000000000004120, regno=1, name=0x60000fffffffb328 "r0", namelen=32, prefix=0x60000fffffffb318, setname=0x60000fffffffb320, bits=0x60000fffffffb314, type=0x60000fffffffb310) at ppc_regs.c:45

#1 0x20000000000ba2c0 in ebl_register_info (ebl=0x6000000000004120, regno=1, name=0x60000fffffffb328 "r0", namelen=32, prefix=0x60000fffffffb318, setname=0x60000fffffffb320, bits=0x60000fffffffb314, type=0x60000fffffffb310)

at eblreginfo.c:48

#2 0x20000000000a4fa0 in dwfl_module_register_names (mod=0x60000000000062d0, func=<optimized out>, arg=0x60000fffffffb3a0) at dwfl_module_register_names.c:63

#3 0x4000000000001bd0 in handle_cfi (stuff=0x60000fffffffb3a0, pc=268436672, which=0x4000000000002318 ".debug_frame", dwfl=0x60000000000042f0, cfi=<optimized out>) at addrcfi.c:153

#4 handle_cfi (dwfl=0x60000000000042f0, which=0x4000000000002318 ".debug_frame", cfi=0x6000000000007420, pc=268436672, stuff=0x60000fffffffb3a0) at addrcfi.c:107

#5 0x4000000000001f50 in handle_address (pc=268436672, dwfl=0x60000000000042f0) at addrcfi.c:167

#6 0x40000000000010b0 in main (argc=4, argv=0x60000fffffffb678) at addrcfi.c:216

(gdb) step

48 if (regno < 0 || regno > 1155 || namelen < 8)

(gdb) step

52 *bits = ebl->machine == EM_PPC64 ? 64 : 32;

(gdb) step

51 *prefix = "";

(gdb) step

46 return 1156;

(gdb) step

51 *prefix = "";

(gdb) step

45 if (name == NULL)

(gdb) step

48 if (regno < 0 || regno > 1155 || namelen < 8)

(gdb) step

52 *bits = ebl->machine == EM_PPC64 ? 64 : 32;

(gdb) step

54 : regno < 64 ? DW_ATE_float : DW_ATE_unsigned);

(gdb) step

51 *prefix = "";

(gdb) step

52 *bits = ebl->machine == EM_PPC64 ? 64 : 32;

(gdb) step

54 : regno < 64 ? DW_ATE_float : DW_ATE_unsigned);

(gdb) step

56 if (regno < 32 || regno == 64 || regno == 66)

(gdb) step

53 *type = (regno < 32 ? DW_ATE_signed

(gdb) step

56 if (regno < 32 || regno == 64 || regno == 66)

(gdb) step

57 *setname = "integer";

(gdb) step

72 switch (regno)

(gdb) step

57 *setname = "integer";

(gdb) step

72 switch (regno)

(gdb) step

75 name[0] = 'r';

(gdb) step

77 namelen = 2;

(gdb) step

75 name[0] = 'r';

(gdb) step

76 name[1] = regno + '0';

(gdb) step

78 break;

(gdb) step

75 name[0] = 'r';

(gdb) step

195 name[namelen++] = '\0';

(gdb) step

76 name[1] = regno + '0';

(gdb) step

195 name[namelen++] = '\0';

(gdb) step

196 return namelen;

(gdb) step

ebl_register_info (ebl=0x6000000000004120, regno=1, name=0x60000fffffffb328 "r1", namelen=32, prefix=0x60000fffffffb318, setname=0x60000fffffffb320, bits=0x60000fffffffb314, type=0x60000fffffffb310) at eblreginfo.c:50

50 }

(gdb)

That's rather confusing to read. The code was compiled with "-O2 -g", perhaps I should try -O0 first to rule out a compiler bug? If so, how do I build it with -O0?

Patrick