From mboxrd@z Thu Jan  1 00:00:00 1970
From: Toshi Morita <tm2@best.com>
To: binutils@sourceware.cygnus.com
Subject: Weird relocations
Date: Fri, 24 Sep 1999 16:18:00 -0000
Message-id: <199909242316.QAA01124@shell14.ba.best.com>
X-SW-Source: 1999-09/msg00166.html

I'm still examining the problem whereby an ELF executable is generated with
an invalid AT_low_pc, and I think I'm getting further on the problem.

Basically, It looks like the linker is applying the relocation against a 
nonexistent section possibly due to an assembler bug generating a bad
object file.

When this code in bfd/elf32-sh.c is executed:

      r_symndx = ELF32_R_SYM (rel->r_info);
...
      if (r_symndx < symtab_hdr->sh_info)
        {
          /* There is nothing to be done for an internal IND12W
             relocation.  FIXME: This is probably wrong, but it's how
             the COFF relocations work.  */
          if (r_type == (int) R_SH_IND12W)
            continue;
          sym = local_syms + r_symndx;
          sec = local_sections[r_symndx];
          relocation = (sec->output_section->vma
                        + sec->output_offset
                        + sym->st_value);
        }

the pointer "sec" is assigned a null value because r_symndex seems
to be invalid (when run in the debugger).

When I go dump out the relocations of that object file with sh-elf-objdump
--reloc, I see some suspicious relocations:

RELOCATION RECORDS FOR [.debug]:
OFFSET   TYPE              VALUE
00000008 R_SH_DIR32        .debug
00000053 R_SH_DIR32        .text
00000059 R_SH_DIR32        .text
0000005f R_SH_DIR32        .line
0000007c R_SH_DIR32        .debug_sfnames
00000082 R_SH_DIR32        .debug_srcinfo
0000008e R_SH_DIR32        .debug
000000b4 R_SH_DIR32        .debug
000000d9 R_SH_DIR32        .debug
...
0000b516 R_SH_DIR32        .debug
0000b51c R_SH_DIR32        .debug
0000b522 R_SH_DIR32        _bSqrt__Ff		<- here
0000b528 R_SH_DIR32        .L_f301_e		<- here
0000b52e R_SH_DIR32        .L_b301		<- here
0000b534 R_SH_DIR32        .L_b301_e		<- here

These relocations seems suspicious because all the other entries in the "VALUE"
field are names of sections, but these three are label names... and they are
also the relocations which are not properly applied.

Am I correct in assuming the "VALUE" field of a .debug relocation should
always contain a reference to a section, and not a label? And if so,
are these relocations clearly incorrect?

Toshi