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Enable elf_backend_rela_normal for AArch64

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If we are generating non-relocatable object and --emit-relocs specified,
  aarch64 ld is actually generating wrong addend for rela entry when
  relocate against local symbol.

  for example, for simple testcase

  foo.c
  ===

  const char * const a = "foo";

  const char *
  foo ()
  {
    return a;
  }

  bar.c
  ===

  const char * const b = "bar";

  const char * bar ()
  {
    return b;
  }

  aarch64-none-linux-gnu-ld --emit-relocs -o x.o  foo.o bar.o
  aarch64-none-linux-gnu-readelf -r x.o

   ... R_AARCH64_ADR_PRE 0000000000400018 .rodata + 0
   ... R_AARCH64_ADD_ABS 0000000000400018 .rodata + 0
   ... R_AARCH64_ADR_PRE 0000000000400018 .rodata + 0
   ... R_AARCH64_ADD_ABS 0000000000400018 .rodata + 0

   while it should be:

   ... R_AARCH64_ADR_PRE 0000000000400018 .rodata + 0
   ... R_AARCH64_ADD_ABS 0000000000400018 .rodata + 0
   ... R_AARCH64_ADR_PRE 0000000000400018 .rodata + 10
   ... R_AARCH64_ADD_ABS 0000000000400018 .rodata + 10

   bfd generic code could actually handle this properly, but only when
   elf_backend_rela_normal set to '1'.

   this patch enable this and remove those target specific hack.

    bfd/
      * elfnn-aarch64.c (elf_backend_rela_normal): Set to 1.
      (elfNN_aarch64_relocate_section): Remove duplicated addend adjustment
      when info->relocatable be true.

    ld/testsuite/
      * ld-aarch64/emit-relocs-local-addend-bar.s: * New source file.
      * ld-aarch64/emit-relocs-local-addend-foo.s: * Likewise.
      * ld-aarch64/emit-relocs-local-addend.d: * New testcase.
      * ld-aarch64/local-addend-r.d: Likewise.
This commit is contained in:
Jiong Wang 2014-07-08 09:29:06 +01:00
parent 1f267ae3d1
commit 2e0488d33f
8 changed files with 90 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
bfd/ChangeLog
View File

@ -1,3 +1,9 @@
2014-07-08 Jiong Wang <jiong.wang@arm.com>
* elfnn-aarch64.c (elf_backend_rela_normal): Set to 1.
(elfNN_aarch64_relocate_section): Remove duplicated addend adjustment
when info->relocatable be true.
2014-07-07 Barney Stratford <barney_stratford@fastmail.fm> 2014-07-07 Barney Stratford <barney_stratford@fastmail.fm>
* elf32-avr.c: Handle R_AVR_PORT5 and R_AVR_PORT6. * elf32-avr.c: Handle R_AVR_PORT5 and R_AVR_PORT6.

9
bfd/elfnn-aarch64.c
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@ -4158,15 +4158,7 @@ elfNN_aarch64_relocate_section (bfd *output_bfd,
rel, 1, relend, howto, 0, contents); rel, 1, relend, howto, 0, contents);
if (info->relocatable) if (info->relocatable)
{
/* This is a relocatable link. We don't have to change
anything, unless the reloc is against a section symbol,
in which case we have to adjust according to where the
section symbol winds up in the output section. */
if (sym != NULL && ELF_ST_TYPE (sym->st_info) == STT_SECTION)
rel->r_addend += sec->output_offset;
continue; continue;
}
if (h != NULL) if (h != NULL)
name = h->root.root.string; name = h->root.root.string;
@ -7288,6 +7280,7 @@ const struct elf_size_info elfNN_aarch64_size_info =
#define elf_backend_may_use_rel_p 0 #define elf_backend_may_use_rel_p 0
#define elf_backend_may_use_rela_p 1 #define elf_backend_may_use_rela_p 1
#define elf_backend_default_use_rela_p 1 #define elf_backend_default_use_rela_p 1
#define elf_backend_rela_normal 1
#define elf_backend_got_header_size (GOT_ENTRY_SIZE * 3) #define elf_backend_got_header_size (GOT_ENTRY_SIZE * 3)
#define elf_backend_default_execstack 0 #define elf_backend_default_execstack 0

7
ld/testsuite/ChangeLog
View File

@ -1,3 +1,10 @@
2014-07-08 Jiong Wang <jiong.wang@arm.com>
* ld-aarch64/emit-relocs-local-addend-bar.s: New source file.
* ld-aarch64/emit-relocs-local-addend-foo.s: Likewise.
* ld-aarch64/emit-relocs-local-addend.d: New testcase.
* ld-aarch64/local-addend-r.d: Likewise.
2014-07-08 Alan Modra <amodra@gmail.com> 2014-07-08 Alan Modra <amodra@gmail.com>
PR 17112 PR 17112

4
ld/testsuite/ld-aarch64/aarch64-elf.exp
View File

@ -87,6 +87,10 @@ run_dump_test "emit-relocs-309-low-bad"
run_dump_test "emit-relocs-311" run_dump_test "emit-relocs-311"
run_dump_test "emit-relocs-312" run_dump_test "emit-relocs-312"
# test addend correctness when --emit-relocs specified for non-relocatable obj.
run_dump_test "emit-relocs-local-addend"
# test addend correctness when -r specified.
run_dump_test "local-addend-r"
run_dump_test "limit-b" run_dump_test "limit-b"
run_dump_test "limit-bl" run_dump_test "limit-bl"

19
ld/testsuite/ld-aarch64/emit-relocs-local-addend-bar.s Normal file
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@ -0,0 +1,19 @@
.global b
.section .rodata
.align 3
.LC0:
.string "bar"
.align 3
.type b, %object
.size b, 8
b:
.xword .LC0
.text
.align 2
.global bar
.type bar, %function
bar:
adrp x0, .LC0
add x0, x0, :lo12:.LC0
ret
.size bar, .-bar

20
ld/testsuite/ld-aarch64/emit-relocs-local-addend-foo.s Normal file
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@ -0,0 +1,20 @@
.cpu generic+fp+simd
.global a
.section .rodata
.align 3
.LC0:
.string "foo"
.align 3
.type a, %object
.size a, 8
a:
.xword .LC0
.text
.align 2
.global foo
.type foo, %function
foo:
adrp x0, .LC0
add x0, x0, :lo12:.LC0
ret
.size foo, .-foo

16
ld/testsuite/ld-aarch64/emit-relocs-local-addend.d Normal file
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@ -0,0 +1,16 @@
#source: emit-relocs-local-addend-foo.s
#source: emit-relocs-local-addend-bar.s
#ld: -e0 --emit-relocs
#readelf: -r
Relocation section '\.rela\.text' at offset 0x102f8 contains 4 entries:
Offset Info Type Sym\. Value Sym\. Name \+ Addend
000000400000 000200000113 R_AARCH64_ADR_PRE 0000000000400018 \.rodata \+ 0
000000400004 000200000115 R_AARCH64_ADD_ABS 0000000000400018 \.rodata \+ 0
00000040000c 000200000113 R_AARCH64_ADR_PRE 0000000000400018 \.rodata \+ 10
000000400010 000200000115 R_AARCH64_ADD_ABS 0000000000400018 \.rodata \+ 10
Relocation section '\.rela\.rodata' at offset 0x10358 contains 2 entries:
Offset Info Type Sym\. Value Sym. Name \+ Addend
000000400020 000200000101 R_AARCH64_ABS64 0000000000400018 \.rodata \+ 0
000000400030 000200000101 R_AARCH64_ABS64 0000000000400018 \.rodata \+ 10

16
ld/testsuite/ld-aarch64/local-addend-r.d Normal file
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@ -0,0 +1,16 @@
#source: emit-relocs-local-addend-foo.s
#source: emit-relocs-local-addend-bar.s
#ld: -e0 -r
#readelf: -r
Relocation section '\.rela\.text' at offset 0x338 contains 4 entries:
Offset Info Type Sym\. Value Sym\. Name \+ Addend
000000000000 000200000113 R_AARCH64_ADR_PRE 0000000000000000 \.rodata \+ 0
000000000004 000200000115 R_AARCH64_ADD_ABS 0000000000000000 \.rodata \+ 0
00000000000c 000200000113 R_AARCH64_ADR_PRE 0000000000000000 \.rodata \+ 10
000000000010 000200000115 R_AARCH64_ADD_ABS 0000000000000000 \.rodata \+ 10
Relocation section '\.rela\.rodata' at offset 0x398 contains 2 entries:
Offset Info Type Sym\. Value Sym. Name \+ Addend
000000000008 000200000101 R_AARCH64_ABS64 0000000000000000 \.rodata \+ 0
000000000018 000200000101 R_AARCH64_ABS64 0000000000000000 \.rodata \+ 10