* [PATCH] objdump relocation fixes for ARM disassembly
@ 2005-02-22 22:54 Stig Petter Olsrød
2005-03-01 15:17 ` Nick Clifton
0 siblings, 1 reply; 2+ messages in thread
From: Stig Petter Olsrød @ 2005-02-22 22:54 UTC (permalink / raw)
To: binutils
Hello,
objdump disassembly did not relocate correctly for the ARM processor. It seems
that the test for triggering the INSN_HAS_RELOC flag was void (one test killed the other,
since octets would always be zero) and all relocations would thus fail. I changed the test
so the flag is set when we are about to disassemble an insn that the current relocation
entry points to. I also changed objdump_print_addr to use the current relocation entry if
the insn has such an entry. This causes the symbol printed to be correct for both external
symbols (from the undefined section) and local symbols.
This has only been tested for the ARM processor, but I don't think it should break other
DISASSEMBLER_NEEDS_RELOCS processors either.
binutils/
2005-02-22 Stig Petter Olsroed <stigpo@users.sourceforge.net>
* objdump.c (disassemble_bytes): Fixed relocation check for
DISASSEMBLER_NEEDS_RELOCS platforms to properly trigger the
INSN_HAS_RELOC flag. Set the current relocation entry in
objdump_disasm_info to allow printing the proper symbol.
(objdump_print_addr): Use the relocation entry in
objdump_disasm_info to lookup the correct symbol for
DISASSEMBLER_NEEDS_RELOCS platforms.
--- binutils/objdump.c 2005-02-22 01:50:06.000000000 +0100
+++ binutils/objdump.c 2005-02-22 14:27:33.066960900 +0100
@@ -128,6 +128,7 @@
arelent ** dynrelbuf;
long dynrelcount;
disassembler_ftype disassemble_fn;
+ arelent * reloc;
};
/* Architecture to disassemble for, or default if NULL. */
@@ -852,6 +853,8 @@
{
struct objdump_disasm_info *aux;
asymbol *sym;
+ arelent *q;
+ int skip_find = 0;
if (sorted_symcount < 1)
{
@@ -861,6 +864,22 @@
}
aux = (struct objdump_disasm_info *) info->application_data;
+
+ q = aux->reloc;
+ if (q != NULL)
+ {
+ if (q->sym_ptr_ptr != NULL && *q->sym_ptr_ptr != NULL)
+ {
+ /* Adjust the vma to the reloc */
+ vma += bfd_asymbol_value (*q->sym_ptr_ptr);
+ if (bfd_is_und_section (bfd_get_section (*q->sym_ptr_ptr)))
+ {
+ skip_find = 1;
+ sym = *q->sym_ptr_ptr;
+ }
+ }
+ }
+ if (!skip_find)
sym = find_symbol_for_address (vma, info, NULL);
objdump_print_addr_with_sym (aux->abfd, aux->sec, sym, vma, info,
skip_zeroes);
@@ -1350,16 +1369,22 @@
info->bytes_per_chunk = 0;
#ifdef DISASSEMBLER_NEEDS_RELOCS
- /* FIXME: This is wrong. It tests the number of octets
- in the last instruction, not the current one. */
- if (*relppp < relppend
- && (**relppp)->address >= rel_offset + addr_offset
- && ((**relppp)->address
- < rel_offset + addr_offset + octets / opb))
+ /* Check if the current relocation entry applies to the
+ instruction we are about to disassemble.
+ This works for ARM at least.
+ */
+ if ((*relppp) < relppend
+ && ((**relppp)->address == rel_offset + addr_offset))
+ {
info->flags = INSN_HAS_RELOC;
+ aux->reloc = **relppp;
+ }
else
#endif
+ {
info->flags = 0;
+ aux->reloc = NULL;
+ }
octets = (*disassemble_fn) (section->vma + addr_offset, info);
info->fprintf_func = (fprintf_ftype) fprintf;
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] objdump relocation fixes for ARM disassembly
2005-02-22 22:54 [PATCH] objdump relocation fixes for ARM disassembly Stig Petter Olsrød
@ 2005-03-01 15:17 ` Nick Clifton
0 siblings, 0 replies; 2+ messages in thread
From: Nick Clifton @ 2005-03-01 15:17 UTC (permalink / raw)
To: Stig Petter Olsrød; +Cc: binutils
[-- Attachment #1: Type: text/plain, Size: 2027 bytes --]
Hi Stig,
> 2005-02-22 Stig Petter Olsroed <stigpo@users.sourceforge.net>
>
> * objdump.c (disassemble_bytes): Fixed relocation check for
> DISASSEMBLER_NEEDS_RELOCS platforms to properly trigger the
> INSN_HAS_RELOC flag. Set the current relocation entry in
> objdump_disasm_info to allow printing the proper symbol.
> (objdump_print_addr): Use the relocation entry in
> objdump_disasm_info to lookup the correct symbol for
> DISASSEMBLER_NEEDS_RELOCS platforms.
Well this is a good idea - but it does have a couple of problems:
1. The new 'relocs' field of the aux structure is not initialised in
disassemble_data().
2. The revised test inside DISASSEMBLER_NEEDS_INFO will not work
with relocs whose address is part way through an instruction. eg on
VLIW architectures.
3. The patch does not adjust the GAS testsuite files to take account
of the new behaviour of the disassembler.
So I have amended your patch (as attached) and checked it in with the
following ChangeLog entries.
Cheers
Nick
binutils/ChangeLog
2005-03-01 Stig Petter Olsroed <stigpo@users.sourceforge.net>
Nick Clifton <nickc@redhat.com>
* objdump.c: Fix coding for DISASSEMBLER_NEEDS_RELOC:
(struct objdump_disasm_info): Add 'reloc' field.
(disassemble_bytes): Fix check for when an insn has a reloc
associated with it. Improve comment explaining why the use of
octets is wrong. Set the 'reloc' field in objdump_disasm_info
structure.
(objdump_print_addr): Use new 'reloc' field to lookup the correct
address for the symbol associated with the current instruction's
relocation.
(disassemble_info): Initialise 'reloc' field.
gas/testsuite/ChangeLog
2005-03-01 Stig Petter Olsroed <stigpo@users.sourceforge.net>
Nick Clifton <nickc@redhat.com>
* gas/arm/inst.d: Allow for ARM ports which decode the reloc
associated with branches and so show the exact symbolic destination
address rather than an offset from the start of the section.
* gas/arm/pic.d: Likewise.
[-- Attachment #2: arm-objdump.patch --]
[-- Type: text/plain, Size: 7800 bytes --]
Index: binutils/objdump.c
===================================================================
RCS file: /cvs/src/src/binutils/objdump.c,v
retrieving revision 1.100
diff -c -3 -p -r1.100 objdump.c
*** binutils/objdump.c 23 Feb 2005 12:25:57 -0000 1.100
--- binutils/objdump.c 1 Mar 2005 14:52:56 -0000
*************** struct objdump_disasm_info
*** 128,133 ****
--- 128,136 ----
arelent ** dynrelbuf;
long dynrelcount;
disassembler_ftype disassemble_fn;
+ #ifdef DISASSEMBLER_NEEDS_RELOCS
+ arelent * reloc;
+ #endif
};
/* Architecture to disassemble for, or default if NULL. */
*************** objdump_print_addr (bfd_vma vma,
*** 852,857 ****
--- 855,863 ----
{
struct objdump_disasm_info *aux;
asymbol *sym;
+ #ifdef DISASSEMBLER_NEEDS_RELOCS
+ bfd_boolean skip_find = FALSE;
+ #endif
if (sorted_symcount < 1)
{
*************** objdump_print_addr (bfd_vma vma,
*** 861,867 ****
}
aux = (struct objdump_disasm_info *) info->application_data;
! sym = find_symbol_for_address (vma, info, NULL);
objdump_print_addr_with_sym (aux->abfd, aux->sec, sym, vma, info,
skip_zeroes);
}
--- 867,891 ----
}
aux = (struct objdump_disasm_info *) info->application_data;
!
! #ifdef DISASSEMBLER_NEEDS_RELOCS
! if (aux->reloc != NULL
! && aux->reloc->sym_ptr_ptr != NULL
! && * aux->reloc->sym_ptr_ptr != NULL)
! {
! sym = * aux->reloc->sym_ptr_ptr;
!
! /* Adjust the vma to the reloc. */
! vma += bfd_asymbol_value (sym);
!
! if (bfd_is_und_section (bfd_get_section (sym)))
! skip_find = TRUE;
! }
!
! if (!skip_find)
! #endif
! sym = find_symbol_for_address (vma, info, NULL);
!
objdump_print_addr_with_sym (aux->abfd, aux->sec, sym, vma, info,
skip_zeroes);
}
*************** disassemble_bytes (struct disassemble_in
*** 1238,1243 ****
--- 1262,1268 ----
unsigned int opb = info->octets_per_byte;
unsigned int skip_zeroes = info->skip_zeroes;
unsigned int skip_zeroes_at_end = info->skip_zeroes_at_end;
+ int octets = opb;
SFILE sfile;
aux = (struct objdump_disasm_info *) info->application_data;
*************** disassemble_bytes (struct disassemble_in
*** 1282,1289 ****
while (addr_offset < stop_offset)
{
bfd_vma z;
- int octets = 0;
bfd_boolean need_nl = FALSE;
/* If we see more than SKIP_ZEROES octets of zeroes, we just
print `...'. */
--- 1307,1320 ----
while (addr_offset < stop_offset)
{
bfd_vma z;
bfd_boolean need_nl = FALSE;
+ #ifdef DISASSEMBLER_NEEDS_RELOCS
+ int previous_octets;
+
+ /* Remember the length of the previous instruction. */
+ previous_octets = octets;
+ #endif
+ octets = 0;
/* If we see more than SKIP_ZEROES octets of zeroes, we just
print `...'. */
*************** disassemble_bytes (struct disassemble_in
*** 1348,1366 ****
info->stream = (FILE *) &sfile;
info->bytes_per_line = 0;
info->bytes_per_chunk = 0;
#ifdef DISASSEMBLER_NEEDS_RELOCS
! /* FIXME: This is wrong. It tests the number of octets
! in the last instruction, not the current one. */
! if (*relppp < relppend
! && (**relppp)->address >= rel_offset + addr_offset
! && ((**relppp)->address
! < rel_offset + addr_offset + octets / opb))
! info->flags = INSN_HAS_RELOC;
! else
! #endif
! info->flags = 0;
octets = (*disassemble_fn) (section->vma + addr_offset, info);
info->fprintf_func = (fprintf_ftype) fprintf;
info->stream = stdout;
--- 1379,1418 ----
info->stream = (FILE *) &sfile;
info->bytes_per_line = 0;
info->bytes_per_chunk = 0;
+ info->flags = 0;
#ifdef DISASSEMBLER_NEEDS_RELOCS
! if (*relppp < relppend)
! {
! bfd_signed_vma distance_to_rel;
!
! distance_to_rel = (**relppp)->address
! - (rel_offset + addr_offset);
+ /* Check to see if the current reloc is associated with
+ the instruction that we are about to disassemble. */
+ if (distance_to_rel == 0
+ /* FIXME: This is wrong. We are trying to catch
+ relocs that are addressed part way through the
+ current instruction, as might happen with a packed
+ VLIW instruction. Unfortunately we do not know the
+ length of the current instruction since we have not
+ disassembled it yet. Instead we take a guess based
+ upon the length of the previous instruction. The
+ proper solution is to have a new target-specific
+ disassembler function which just returns the length
+ of an instruction at a given address without trying
+ to display its disassembly. */
+ || (distance_to_rel > 0
+ && distance_to_rel < (bfd_signed_vma) (previous_octets/ opb)))
+ {
+ info->flags = INSN_HAS_RELOC;
+ aux->reloc = **relppp;
+ }
+ else
+ aux->reloc = NULL;
+ }
+ #endif
octets = (*disassemble_fn) (section->vma + addr_offset, info);
info->fprintf_func = (fprintf_ftype) fprintf;
info->stream = stdout;
*************** disassemble_data (bfd *abfd)
*** 1817,1822 ****
--- 1869,1877 ----
aux.require_sec = FALSE;
aux.dynrelbuf = NULL;
aux.dynrelcount = 0;
+ #ifdef DISASSEMBLER_NEEDS_RELOCS
+ aux.reloc = NULL;
+ #endif
disasm_info.print_address_func = objdump_print_address;
disasm_info.symbol_at_address_func = objdump_symbol_at_address;
Index: gas/testsuite/gas/arm/inst.d
===================================================================
RCS file: /cvs/src/src/gas/testsuite/gas/arm/inst.d,v
retrieving revision 1.12
diff -c -3 -p -r1.12 inst.d
*** gas/testsuite/gas/arm/inst.d 14 Aug 2003 17:11:08 -0000 1.12
--- gas/testsuite/gas/arm/inst.d 1 Mar 2005 14:52:56 -0000
*************** Disassembly of section .text:
*** 159,171 ****
0+254 <[^>]*> e9c40300 ? stmib r4, {r8, r9}\^
0+258 <[^>]*> ef123456 ? swi 0x00123456
0+25c <[^>]*> 2f000033 ? swics 0x00000033
! 0+260 <[^>]*> ebfffffe ? bl 0+260 <[^>]*>
[ ]*260:.*_wombat.*
! 0+264 <[^>]*> 5bfffffe ? blpl 0+264 <[^>]*>
[ ]*264:.*ARM.*hohum
! 0+268 <[^>]*> eafffffe ? b 0+268 <[^>]*>
[ ]*268:.*_wibble.*
! 0+26c <[^>]*> dafffffe ? ble 0+26c <[^>]*>
[ ]*26c:.*testerfunc.*
0+270 <[^>]*> e1a01102 ? mov r1, r2, lsl #2
0+274 <[^>]*> e1a01002 ? mov r1, r2
--- 159,171 ----
0+254 <[^>]*> e9c40300 ? stmib r4, {r8, r9}\^
0+258 <[^>]*> ef123456 ? swi 0x00123456
0+25c <[^>]*> 2f000033 ? swics 0x00000033
! 0+260 <[^>]*> ebfffffe ? bl 0[0123456789abcdef]+ <[^>]*>
[ ]*260:.*_wombat.*
! 0+264 <[^>]*> 5bfffffe ? blpl 0[0123456789abcdef]+ <[^>]*>
[ ]*264:.*ARM.*hohum
! 0+268 <[^>]*> eafffffe ? b 0[0123456789abcdef]+ <[^>]*>
[ ]*268:.*_wibble.*
! 0+26c <[^>]*> dafffffe ? ble 0[0123456789abcdef]+ <[^>]*>
[ ]*26c:.*testerfunc.*
0+270 <[^>]*> e1a01102 ? mov r1, r2, lsl #2
0+274 <[^>]*> e1a01002 ? mov r1, r2
Index: gas/testsuite/gas/arm/pic.d
===================================================================
RCS file: /cvs/src/src/gas/testsuite/gas/arm/pic.d,v
retrieving revision 1.8
diff -c -3 -p -r1.8 pic.d
*** gas/testsuite/gas/arm/pic.d 17 Sep 2004 12:35:00 -0000 1.8
--- gas/testsuite/gas/arm/pic.d 1 Mar 2005 14:52:56 -0000
***************
*** 8,14 ****
Disassembly of section .text:
00+0 <[^>]*> ebfffffe bl 00+0 <[^>]*>
0: R_ARM_PC24 foo
! 00+4 <[^>]*> ebfffffe bl 00+4 <[^>]*>
4: R_ARM_PLT32 foo
\.\.\.
8: R_ARM_ABS32 sym
--- 8,14 ----
Disassembly of section .text:
00+0 <[^>]*> ebfffffe bl 00+0 <[^>]*>
0: R_ARM_PC24 foo
! 00+4 <[^>]*> ebfffffe bl 0[0123456789abcdef]+ <[^>]*>
4: R_ARM_PLT32 foo
\.\.\.
8: R_ARM_ABS32 sym
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2005-02-22 22:54 [PATCH] objdump relocation fixes for ARM disassembly Stig Petter Olsrød
2005-03-01 15:17 ` Nick Clifton
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