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PATCH: PR ld/3958: ELF linker failed to handle relocation against STN_UNDEF
- From: "H. J. Lu" <hjl at lucon dot org>
- To: binutils at sourceware dot org
- Date: Sat, 3 Mar 2007 15:04:22 -0800
- Subject: PATCH: PR ld/3958: ELF linker failed to handle relocation against STN_UNDEF
- References: <877iu4k03j.fsf@firetop.home> <20070227014036.GA9676@caradoc.them.org> <87mz309c9k.fsf@firetop.home> <20070227121051.GA5903@caradoc.them.org> <20070227230314.GL29005@bubble.grove.modra.org> <20070228012241.GB11623@lucon.org> <20070228013530.GN29005@bubble.grove.modra.org> <20070303032002.GA13632@lucon.org>
On Fri, Mar 02, 2007 at 07:20:02PM -0800, H. J. Lu wrote:
> On Wed, Feb 28, 2007 at 12:05:30PM +1030, Alan Modra wrote:
> > On Tue, Feb 27, 2007 at 05:22:41PM -0800, H. J. Lu wrote:
> > > There are no regressions with my patch. But I don't know if there
> > > are testcases to check ld -r and ld -emit-relocs for this specific
> > > case.
> >
> > I don't think there is a testcase for this case in the testsuite.
> > I'll approve your patch if you implement what I suggested in my last
> > email.
> >
>
> Here is the updated patch with a testcase for -r and a testcase for
> -emit-relocs.
>
This adds a bit field to Elf_Internal_Rela. This patch uses more
memory. But we shouldn't use STN_UNDEF to indicate relocations
against symbols from removed input sections since STN_UNDEF simply
means 0 as the symbol value for relocation.
H.J.
---
bfd/
2007-03-03 H.J. Lu <hongjiu.lu@intel.com>
PR ld/3958
* elf32-arm.c (elf32_arm_final_link_relocate): Check r_discarded
for relocations against symbols from removed input sections.
* elf32-d10v.c (elf32_d10v_relocate_section): Likewise.
* elf32-hppa.c (elf32_hppa_relocate_section): Likewise.
* elf32-i386.c (elf_i386_relocate_section): Likewise.
* elf32-ppc.c (ppc_elf_relocate_section): Likewise.
* elf32-s390.c (elf_s390_relocate_section): Likewise.
* elf32-score.c (score_elf_final_link_relocate): Likewise.
* elf32-sh.c (sh_elf_relocate_section): Likewise.
* elf32-xtensa.c (elf_xtensa_relocate_section): Likewise.
* elf64-alpha.c (elf64_alpha_relocate_section): Likewise.
* elf64-ppc.c (ppc64_elf_relocate_section): Likewise.
* elf64-s390.c (elf_s390_relocate_section): Likewise.
* elf64-x86-64.c (elf64_x86_64_relocate_section): Likewise.
* elfxx-ia64.c (elfNN_ia64_relocate_section): Likewise.
* elfxx-mips.c (mips_elf_calculate_relocation): Likewise.
* elfxx-sparc.c (_bfd_sparc_elf_relocate_section): Likewise.
* elf32-xtensa.c (move_literal): Initialize r_discarded to 0.
* elf64-mips.c (mips_elf64_be_swap_reloc_in): Likewise.
(mips_elf64_be_swap_reloca_in): Likewise.
* elfcode.h (elf_swap_reloc_in): Likewise.
(elf_swap_reloca_in): Likewise.
* elflink.c (elf_link_input_bfd): Set r_discarded to 1 for
relocations against symbols from removed input sections.
include/elf/
2007-03-03 H.J. Lu <hongjiu.lu@intel.com>
* internal.h (Elf_Internal_Rela): Add r_discarded.
ld/testsuite/
2007-03-03 H.J. Lu <hongjiu.lu@intel.com>
PR ld/3958
* ld-elf/linkonce1.d: New file.
* ld-elf/linkonce1a.s: Likewise.
* ld-elf/linkonce1b.s: Likewise.
* ld-elf/linkonce2.d: Likewise.
* ld-i386/pcrel16abs.d: Likewise.
* ld-i386/pcrel16abs.s: Likewise.
* ld-i386/i386.exp: Run "pcrel16abs".
--- binutils/bfd/elf32-arm.c.abs 2007-03-01 14:53:13.000000000 -0800
+++ binutils/bfd/elf32-arm.c 2007-03-03 14:48:39.000000000 -0800
@@ -4524,10 +4524,7 @@ elf32_arm_final_link_relocate (reloc_how
case R_ARM_XPC25:
case R_ARM_PREL31:
case R_ARM_PLT32:
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
_bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
return bfd_reloc_ok;
--- binutils/bfd/elf32-d10v.c.abs 2006-11-02 19:36:06.000000000 -0800
+++ binutils/bfd/elf32-d10v.c 2007-03-03 14:25:46.000000000 -0800
@@ -469,12 +469,11 @@ elf32_d10v_relocate_section (bfd *output
unresolved_reloc, warned);
}
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
- /* r_symndx will be zero only for relocs against symbols from
- removed linkonce sections, or sections discarded by a linker
- script. For these relocs, we just want the section contents
- zeroed. Avoid any special processing. */
+ /* For relocs against symbols from removed linkonce sections,
+ or sections discarded by a linker script, we just want the
+ section contents zeroed. Avoid any special processing. */
_bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
continue;
}
--- binutils/bfd/elf32-hppa.c.abs 2007-03-02 15:10:48.000000000 -0800
+++ binutils/bfd/elf32-hppa.c 2007-03-03 14:26:40.000000000 -0800
@@ -3939,10 +3939,7 @@ elf32_hppa_relocate_section (bfd *output
case R_PARISC_DPREL14R:
case R_PARISC_DPREL21L:
case R_PARISC_DIR32:
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
- if (r_symndx == 0)
+ if (rela->r_discarded)
{
_bfd_clear_contents (elf_hppa_howto_table + r_type, input_bfd,
contents + rela->r_offset);
--- binutils/bfd/elf32-i386.c.abs 2007-03-02 15:10:48.000000000 -0800
+++ binutils/bfd/elf32-i386.c 2007-03-03 14:26:54.000000000 -0800
@@ -2414,12 +2414,11 @@ elf_i386_relocate_section (bfd *output_b
unresolved_reloc, warned);
}
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
- /* r_symndx will be zero only for relocs against symbols from
- removed linkonce sections, or sections discarded by a linker
- script. For these relocs, we just want the section contents
- zeroed. Avoid any special processing. */
+ /* For relocs against symbols from removed linkonce sections,
+ or sections discarded by a linker script, we just want the
+ section contents zeroed. Avoid any special processing. */
_bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
continue;
}
--- binutils/bfd/elf32-ppc.c.abs 2007-02-01 12:42:10.000000000 -0800
+++ binutils/bfd/elf32-ppc.c 2007-03-03 14:27:17.000000000 -0800
@@ -6225,11 +6225,8 @@ ppc_elf_relocate_section (bfd *output_bf
case R_PPC_ADDR14_BRNTAKEN:
case R_PPC_UADDR32:
case R_PPC_UADDR16:
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
dodyn:
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
_bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
break;
--- binutils/bfd/elf32-s390.c.abs 2006-11-02 19:36:07.000000000 -0800
+++ binutils/bfd/elf32-s390.c 2007-03-03 14:27:40.000000000 -0800
@@ -2540,10 +2540,7 @@ elf_s390_relocate_section (output_bfd, i
case R_390_PC16DBL:
case R_390_PC32DBL:
case R_390_PC32:
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
_bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
break;
--- binutils/bfd/elf32-score.c.abs 2007-01-30 07:59:53.000000000 -0800
+++ binutils/bfd/elf32-score.c 2007-03-03 14:27:56.000000000 -0800
@@ -2006,10 +2006,7 @@ score_elf_final_link_relocate (reloc_how
input_section))
return bfd_reloc_undefined;
}
- else if (r_symndx == 0)
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
+ else if (rel->r_discarded)
value = 0;
else
{
--- binutils/bfd/elf32-sh.c.abs 2006-11-02 19:36:07.000000000 -0800
+++ binutils/bfd/elf32-sh.c 2007-03-03 14:28:16.000000000 -0800
@@ -3557,10 +3557,7 @@ sh_elf_relocate_section (bfd *output_bfd
case R_SH_IMM_MEDHI16_PCREL:
case R_SH_IMM_HI16_PCREL:
#endif
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
_bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
continue;
--- binutils/bfd/elf32-xtensa.c.abs 2007-03-02 11:46:35.000000000 -0800
+++ binutils/bfd/elf32-xtensa.c 2007-03-03 14:40:15.000000000 -0800
@@ -2241,12 +2241,11 @@ elf_xtensa_relocate_section (bfd *output
return FALSE;
}
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
- /* r_symndx will be zero only for relocs against symbols from
- removed linkonce sections, or sections discarded by a linker
- script. For these relocs, we just want the section contents
- zeroed. Avoid any special processing. */
+ /* For relocs against symbols from removed linkonce sections,
+ or sections discarded by a linker script, we just want the
+ section contents zeroed. Avoid any special processing. */
_bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
continue;
}
@@ -8708,6 +8707,7 @@ move_literal (bfd *abfd,
this_rela.r_info = ELF32_R_INFO (0, r_type);
this_rela.r_addend =
r_rel->target_offset - r_reloc_get_target_offset (r_rel);
+ this_rela.r_discarded = 0;
bfd_put_32 (abfd, lit->value, contents + offset);
/* Currently, we cannot move relocations during a relocatable link. */
--- binutils/bfd/elf64-alpha.c.abs 2007-03-02 15:10:48.000000000 -0800
+++ binutils/bfd/elf64-alpha.c 2007-03-03 14:38:42.000000000 -0800
@@ -4210,11 +4210,11 @@ elf64_alpha_relocate_section (bfd *outpu
case R_ALPHA_GPREL32:
/* If the target section was a removed linkonce section,
- r_symndx will be zero. In this case, assume that the
- switch will not be used, so don't fill it in. If we
- do nothing here, we'll get relocation truncated messages,
- due to the placement of the application above 4GB. */
- if (r_symndx == 0)
+ assume that the switch will not be used, so don't fill it
+ in. If we do nothing here, we'll get relocation truncated
+ messages, due to the placement of the application above
+ 4GB. */
+ if (rel->r_discarded)
{
r = bfd_reloc_ok;
break;
@@ -4412,10 +4412,9 @@ elf64_alpha_relocate_section (bfd *outpu
}
- /* ??? .eh_frame references to discarded sections will be smashed
- to relocations against SHN_UNDEF. The .eh_frame format allows
- NULL to be encoded as 0 in any format, so this works here. */
- if (r_symndx == 0)
+ /* The .eh_frame format allows NULL to be encoded as 0 in any
+ format, so this works here. */
+ if (rel->r_discarded)
howto = (elf64_alpha_howto_table
+ (r_type - R_ALPHA_SREL32 + R_ALPHA_REFLONG));
goto default_reloc;
--- binutils/bfd/elf64-mips.c.abs 2006-10-28 14:23:34.000000000 -0700
+++ binutils/bfd/elf64-mips.c 2007-03-03 14:18:50.000000000 -0800
@@ -1735,12 +1735,15 @@ mips_elf64_be_swap_reloc_in (bfd *abfd,
dst[0].r_offset = mirel.r_offset;
dst[0].r_info = ELF64_R_INFO (mirel.r_sym, mirel.r_type);
dst[0].r_addend = 0;
+ dst[0].r_discarded = 0;
dst[1].r_offset = mirel.r_offset;
dst[1].r_info = ELF64_R_INFO (mirel.r_ssym, mirel.r_type2);
dst[1].r_addend = 0;
+ dst[1].r_discarded = 0;
dst[2].r_offset = mirel.r_offset;
dst[2].r_info = ELF64_R_INFO (STN_UNDEF, mirel.r_type3);
dst[2].r_addend = 0;
+ dst[2].r_discarded = 0;
}
/* Swap in a MIPS 64-bit Rela reloc. */
@@ -1758,12 +1761,15 @@ mips_elf64_be_swap_reloca_in (bfd *abfd,
dst[0].r_offset = mirela.r_offset;
dst[0].r_info = ELF64_R_INFO (mirela.r_sym, mirela.r_type);
dst[0].r_addend = mirela.r_addend;
+ dst[0].r_discarded = 0;
dst[1].r_offset = mirela.r_offset;
dst[1].r_info = ELF64_R_INFO (mirela.r_ssym, mirela.r_type2);
dst[1].r_addend = 0;
+ dst[1].r_discarded = 0;
dst[2].r_offset = mirela.r_offset;
dst[2].r_info = ELF64_R_INFO (STN_UNDEF, mirela.r_type3);
dst[2].r_addend = 0;
+ dst[2].r_discarded = 0;
}
/* Swap out a MIPS 64-bit Rel reloc. */
--- binutils/bfd/elf64-ppc.c.abs 2007-03-01 14:53:13.000000000 -0800
+++ binutils/bfd/elf64-ppc.c 2007-03-03 14:39:00.000000000 -0800
@@ -10831,11 +10831,8 @@ ppc64_elf_relocate_section (bfd *output_
case R_PPC64_UADDR16:
case R_PPC64_UADDR32:
case R_PPC64_UADDR64:
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
dodyn:
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
_bfd_clear_contents (ppc64_elf_howto_table[r_type], input_bfd,
contents + rel->r_offset);
--- binutils/bfd/elf64-s390.c.abs 2006-11-02 19:36:09.000000000 -0800
+++ binutils/bfd/elf64-s390.c 2007-03-03 14:32:31.000000000 -0800
@@ -2519,10 +2519,7 @@ elf_s390_relocate_section (output_bfd, i
case R_390_PC32:
case R_390_PC32DBL:
case R_390_PC64:
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
_bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
break;
--- binutils/bfd/elf64-x86-64.c.abs 2007-03-02 15:10:48.000000000 -0800
+++ binutils/bfd/elf64-x86-64.c 2007-03-03 14:32:53.000000000 -0800
@@ -2387,11 +2387,7 @@ elf64_x86_64_relocate_section (bfd *outp
case R_X86_64_64:
/* FIXME: The ABI says the linker should make sure the value is
the same when it's zeroextended to 64 bit. */
-
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
_bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
break;
--- binutils/bfd/elfcode.h.abs 2007-02-05 17:27:15.000000000 -0800
+++ binutils/bfd/elfcode.h 2007-03-03 14:54:43.000000000 -0800
@@ -387,6 +387,7 @@ elf_swap_reloc_in (bfd *abfd,
dst->r_offset = H_GET_WORD (abfd, src->r_offset);
dst->r_info = H_GET_WORD (abfd, src->r_info);
dst->r_addend = 0;
+ dst->r_discarded = 0;
}
void
@@ -398,6 +399,7 @@ elf_swap_reloca_in (bfd *abfd,
dst->r_offset = H_GET_WORD (abfd, src->r_offset);
dst->r_info = H_GET_WORD (abfd, src->r_info);
dst->r_addend = H_GET_SIGNED_WORD (abfd, src->r_addend);
+ dst->r_discarded = 0;
}
/* Translate an ELF reloc from internal format to external format. */
--- binutils/bfd/elflink.c.abs 2007-03-02 15:10:48.000000000 -0800
+++ binutils/bfd/elflink.c 2007-03-03 14:13:20.000000000 -0800
@@ -8488,6 +8488,7 @@ elf_link_input_bfd (struct elf_final_lin
fde as bogus. */
rel->r_info &= r_type_mask;
rel->r_addend = 0;
+ rel->r_discarded = 1;
}
}
}
--- binutils/bfd/elfxx-ia64.c.abs 2007-03-02 15:10:48.000000000 -0800
+++ binutils/bfd/elfxx-ia64.c 2007-03-03 14:36:32.000000000 -0800
@@ -4752,10 +4752,7 @@ elfNN_ia64_relocate_section (output_bfd,
case R_IA64_LTV32LSB:
case R_IA64_LTV64MSB:
case R_IA64_LTV64LSB:
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
- if (r_symndx == 0)
+ if (rel->r_discarded)
value = 0;
r = elfNN_ia64_install_value (hit_addr, value, r_type);
@@ -4998,7 +4995,7 @@ elfNN_ia64_relocate_section (output_bfd,
case R_IA64_SEGREL32LSB:
case R_IA64_SEGREL64MSB:
case R_IA64_SEGREL64LSB:
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
/* If the input section was discarded from the output, then
do nothing. */
--- binutils/bfd/elfxx-mips.c.abs 2007-03-01 14:53:14.000000000 -0800
+++ binutils/bfd/elfxx-mips.c 2007-03-03 14:36:18.000000000 -0800
@@ -4323,10 +4323,7 @@ mips_elf_calculate_relocation (bfd *abfd
input_section))
return bfd_reloc_undefined;
}
- else if (r_symndx == 0)
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
+ else if (relocation->r_discarded)
value = 0;
else
{
--- binutils/bfd/elfxx-sparc.c.abs 2006-11-02 19:36:09.000000000 -0800
+++ binutils/bfd/elfxx-sparc.c 2007-03-03 14:34:43.000000000 -0800
@@ -2752,10 +2752,7 @@ _bfd_sparc_elf_relocate_section (bfd *ou
case R_SPARC_L44:
case R_SPARC_UA64:
r_sparc_plt32:
- /* r_symndx will be zero only for relocs against symbols
- from removed linkonce sections, or sections discarded by
- a linker script. */
- if (r_symndx == 0)
+ if (rel->r_discarded)
{
_bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
break;
--- binutils/include/elf/internal.h.abs 2007-03-02 15:10:48.000000000 -0800
+++ binutils/include/elf/internal.h 2007-03-03 14:15:56.000000000 -0800
@@ -122,6 +122,9 @@ typedef struct elf_internal_rela {
bfd_vma r_offset; /* Location at which to apply the action */
bfd_vma r_info; /* Index and Type of relocation */
bfd_vma r_addend; /* Constant addend used to compute value */
+ /* Whether the reloation is against a symbol from discarded section
+ or removed link-once sections. */
+ unsigned int r_discarded : 1;
} Elf_Internal_Rela;
/* dynamic section structure */
--- binutils/ld/testsuite/ld-elf/linkonce1.d.abs 2007-03-02 19:13:05.000000000 -0800
+++ binutils/ld/testsuite/ld-elf/linkonce1.d 2007-03-02 17:55:41.000000000 -0800
@@ -0,0 +1,12 @@
+#source: linkonce1a.s
+#source: linkonce1b.s
+#ld: -r
+#objdump: -r
+
+.*: file format .*
+
+RELOCATION RECORDS FOR \[.debug_frame\]:
+OFFSET[ ]+TYPE[ ]+VALUE[ ]*
+0+[ ]+R_[0-9A-Z_]+[ ]+\*ABS\*
+
+#pass
--- binutils/ld/testsuite/ld-elf/linkonce1a.s.abs 2007-03-02 19:13:01.000000000 -0800
+++ binutils/ld/testsuite/ld-elf/linkonce1a.s 2007-03-02 17:48:13.000000000 -0800
@@ -0,0 +1,3 @@
+ .section .gnu.linkonce.d.dummy,"aw"
+bar:
+ .long 0
--- binutils/ld/testsuite/ld-elf/linkonce1b.s.abs 2007-03-02 19:12:59.000000000 -0800
+++ binutils/ld/testsuite/ld-elf/linkonce1b.s 2007-03-02 17:48:02.000000000 -0800
@@ -0,0 +1,17 @@
+ .globl main
+ .globl start
+ .globl _start
+ .globl __start
+ .text
+main:
+start:
+_start:
+__start:
+ .long 0
+
+ .section .gnu.linkonce.d.dummy,"aw"
+ .long 0
+foo:
+ .long 0
+ .section .debug_frame,"",@progbits
+ .long foo
--- binutils/ld/testsuite/ld-elf/linkonce2.d.abs 2007-03-02 19:13:09.000000000 -0800
+++ binutils/ld/testsuite/ld-elf/linkonce2.d 2007-03-02 17:56:26.000000000 -0800
@@ -0,0 +1,12 @@
+#source: linkonce1a.s
+#source: linkonce1b.s
+#ld: -emit-relocs
+#objdump: -r
+
+.*: file format .*
+
+RELOCATION RECORDS FOR \[.debug_frame\]:
+OFFSET[ ]+TYPE[ ]+VALUE[ ]*
+0+[ ]+R_[0-9A-Z_]+[ ]+\*ABS\*
+
+#pass
--- binutils/ld/testsuite/ld-i386/i386.exp.abs 2007-03-02 15:10:48.000000000 -0800
+++ binutils/ld/testsuite/ld-i386/i386.exp 2007-03-02 17:59:22.000000000 -0800
@@ -113,4 +113,5 @@ run_ld_link_tests $i386tests
run_dump_test "abs"
run_dump_test "pcrel8"
run_dump_test "pcrel16"
+run_dump_test "pcrel16abs"
run_dump_test "alloc"
--- binutils/ld/testsuite/ld-i386/pcrel16abs.d.abs 2007-03-02 15:10:49.000000000 -0800
+++ binutils/ld/testsuite/ld-i386/pcrel16abs.d 2007-03-02 17:59:22.000000000 -0800
@@ -0,0 +1,12 @@
+#name: PCREL16 absolute reloc
+#as: --32
+#ld: -melf_i386 -Ttext 0xfffffff0
+#objdump: -drj.text -m i8086
+
+.*: +file format elf32-i386
+
+Disassembly of section .text:
+
+f+0 <_start>:
+f+0: e9 0d e0[ ]+jmp[ ]+ffffe000 <SEGMENT_SIZE\+0xfffee000>
+#pass
--- binutils/ld/testsuite/ld-i386/pcrel16abs.s.abs 2007-03-02 15:10:49.000000000 -0800
+++ binutils/ld/testsuite/ld-i386/pcrel16abs.s 2007-03-02 17:59:22.000000000 -0800
@@ -0,0 +1,6 @@
+SEGMENT_SIZE = 0x10000
+RVECTOR = 0x00010
+.code16
+ .globl _start
+_start:
+ jmp SEGMENT_SIZE-(0x1f00 +0xf0 +RVECTOR)