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-rw-r--r--bfd/ChangeLog20
-rw-r--r--bfd/bfd-in2.h1
-rw-r--r--bfd/elf32-i386.c357
-rw-r--r--bfd/libbfd.h1
-rw-r--r--bfd/reloc.c2
5 files changed, 336 insertions, 45 deletions
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 3956966..a2e3034 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,23 @@
+2015-10-22 H.J. Lu <hongjiu.lu@intel.com>
+
+ * elf32-i386.c: Include opcode/i386.h.
+ (elf_howto_table): Add R_386_GOT32X.
+ (R_386_ext2): Replace R_386_IRELATIVE with R_386_GOT32X.
+ (elf_i386_reloc_type_lookup): Handle BFD_RELOC_386_GOT32X.
+ (need_convert_mov_to_lea): Renamed to ...
+ (need_convert_load): This.
+ (elf_i386_check_relocs): Handle R_386_GOT32X. Replace
+ need_convert_mov_to_lea with need_convert_load.
+ (elf_i386_gc_sweep_hook): Handle R_386_GOT32X.
+ (elf_i386_size_dynamic_sections): Likewise.
+ (elf_i386_relocate_section): Likewise.
+ (elf_i386_convert_mov_to_lea): Renamed to ...
+ (elf_i386_convert_load): This. Replace need_convert_mov_to_lea
+ with need_convert_load. Support R_386_GOT32X transformations.
+ * reloc.c (BFD_RELOC_386_GOT32X): New.
+ * bfd-in2.h: Regenerated.
+ * libbfd.h: Likewise.
+
2015-10-22 Andreas Krebbel <krebbel@linux.vnet.ibm.com>
* elf32-s390.c (elf_s390_check_relocs): Set the non_got_ref marker
diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 60d7e45..ad246c8 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -3177,6 +3177,7 @@ instruction. */
BFD_RELOC_386_TLS_DESC_CALL,
BFD_RELOC_386_TLS_DESC,
BFD_RELOC_386_IRELATIVE,
+ BFD_RELOC_386_GOT32X,
/* x86-64/elf relocations */
BFD_RELOC_X86_64_GOT32,
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 8c1dadb..f56b39e 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -29,6 +29,7 @@
#include "objalloc.h"
#include "hashtab.h"
#include "dwarf2.h"
+#include "opcode/i386.h"
/* 386 uses REL relocations instead of RELA. */
#define USE_REL 1
@@ -146,9 +147,12 @@ static reloc_howto_type elf_howto_table[]=
HOWTO(R_386_IRELATIVE, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
bfd_elf_generic_reloc, "R_386_IRELATIVE",
TRUE, 0xffffffff, 0xffffffff, FALSE),
+ HOWTO(R_386_GOT32X, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
+ bfd_elf_generic_reloc, "R_386_GOT32X",
+ TRUE, 0xffffffff, 0xffffffff, FALSE),
/* Another gap. */
-#define R_386_ext2 (R_386_IRELATIVE + 1 - R_386_tls_offset)
+#define R_386_ext2 (R_386_GOT32X + 1 - R_386_tls_offset)
#define R_386_vt_offset (R_386_GNU_VTINHERIT - R_386_ext2)
/* GNU extension to record C++ vtable hierarchy. */
@@ -332,6 +336,10 @@ elf_i386_reloc_type_lookup (bfd *abfd ATTRIBUTE_UNUSED,
TRACE ("BFD_RELOC_386_IRELATIVE");
return &elf_howto_table[R_386_IRELATIVE - R_386_tls_offset];
+ case BFD_RELOC_386_GOT32X:
+ TRACE ("BFD_RELOC_386_GOT32X");
+ return &elf_howto_table[R_386_GOT32X - R_386_tls_offset];
+
case BFD_RELOC_VTABLE_INHERIT:
TRACE ("BFD_RELOC_VTABLE_INHERIT");
return &elf_howto_table[R_386_GNU_VTINHERIT - R_386_vt_offset];
@@ -1468,7 +1476,7 @@ elf_i386_tls_transition (struct bfd_link_info *info, bfd *abfd,
/* Rename some of the generic section flags to better document how they
are used here. */
-#define need_convert_mov_to_lea sec_flg0
+#define need_convert_load sec_flg0
/* Look through the relocs for a section during the first phase, and
calculate needed space in the global offset table, procedure linkage
@@ -1580,6 +1588,7 @@ elf_i386_check_relocs (bfd *abfd,
case R_386_PC32:
case R_386_PLT32:
case R_386_GOT32:
+ case R_386_GOT32X:
if (htab->elf.dynobj == NULL)
htab->elf.dynobj = abfd;
if (!_bfd_elf_create_ifunc_sections (htab->elf.dynobj, info))
@@ -1637,6 +1646,7 @@ elf_i386_check_relocs (bfd *abfd,
/* Fall through */
case R_386_GOT32:
+ case R_386_GOT32X:
case R_386_TLS_GD:
case R_386_TLS_GOTDESC:
case R_386_TLS_DESC_CALL:
@@ -1647,7 +1657,10 @@ elf_i386_check_relocs (bfd *abfd,
switch (r_type)
{
default:
- case R_386_GOT32: tls_type = GOT_NORMAL; break;
+ case R_386_GOT32:
+ case R_386_GOT32X:
+ tls_type = GOT_NORMAL;
+ break;
case R_386_TLS_GD: tls_type = GOT_TLS_GD; break;
case R_386_TLS_GOTDESC:
case R_386_TLS_DESC_CALL:
@@ -1948,9 +1961,9 @@ do_size:
return FALSE;
}
- if (r_type == R_386_GOT32
+ if ((r_type == R_386_GOT32 || r_type == R_386_GOT32X)
&& (h == NULL || h->type != STT_GNU_IFUNC))
- sec->need_convert_mov_to_lea = 1;
+ sec->need_convert_load = 1;
}
return TRUE;
@@ -2074,6 +2087,7 @@ elf_i386_gc_sweep_hook (bfd *abfd,
case R_386_TLS_IE:
case R_386_TLS_GOTIE:
case R_386_GOT32:
+ case R_386_GOT32X:
if (h != NULL)
{
if (h->got.refcount > 0)
@@ -2718,14 +2732,27 @@ elf_i386_readonly_dynrelocs (struct elf_link_hash_entry *h, void *inf)
return TRUE;
}
-/* Convert
- mov foo@GOT(%reg), %reg
+/* With the local symbol, foo, we convert
+ mov foo@GOT[(%reg1)], %reg2
+ to
+ lea foo[@GOTOFF(%reg1)], %reg2
+ and convert
+ call/jmp *foo@GOT[(%reg)]
to
- lea foo@GOTOFF(%reg), %reg
- with the local symbol, foo. */
+ nop call foo/jmp foo nop
+ When PIC is false, convert
+ test %reg1, foo@GOT[(%reg2)]
+ to
+ test $foo, %reg1
+ and convert
+ binop foo@GOT[(%reg1)], %reg2
+ to
+ binop $foo, %reg2
+ where binop is one of adc, add, and, cmp, or, sbb, sub, xor
+ instructions. */
static bfd_boolean
-elf_i386_convert_mov_to_lea (bfd *abfd, asection *sec,
+elf_i386_convert_load (bfd *abfd, asection *sec,
struct bfd_link_info *link_info)
{
Elf_Internal_Shdr *symtab_hdr;
@@ -2743,7 +2770,7 @@ elf_i386_convert_mov_to_lea (bfd *abfd, asection *sec,
/* Nothing to do if there is no need or no output. */
if ((sec->flags & (SEC_CODE | SEC_RELOC)) != (SEC_CODE | SEC_RELOC)
- || sec->need_convert_mov_to_lea == 0
+ || sec->need_convert_load == 0
|| bfd_is_abs_section (sec->output_section))
return TRUE;
@@ -2777,32 +2804,92 @@ elf_i386_convert_mov_to_lea (bfd *abfd, asection *sec,
unsigned int r_symndx = ELF32_R_SYM (irel->r_info);
unsigned int indx;
struct elf_link_hash_entry *h;
+ unsigned int opcode;
+ unsigned int modrm;
+ bfd_vma roff;
+ bfd_boolean baseless;
+ Elf_Internal_Sym *isym;
+ unsigned int addend;
+ unsigned int nop;
+ bfd_vma nop_offset;
- if (r_type != R_386_GOT32)
+ if (r_type != R_386_GOT32 && r_type != R_386_GOT32X)
continue;
- /* Get the symbol referred to by the reloc. */
- if (r_symndx < symtab_hdr->sh_info)
+ roff = irel->r_offset;
+ if (roff < 2)
+ continue;
+
+ modrm = bfd_get_8 (abfd, contents + roff - 1);
+ baseless = (modrm & 0xc7) == 0x5;
+
+ if (r_type == R_386_GOT32X
+ && baseless
+ && bfd_link_pic (link_info))
{
- Elf_Internal_Sym *isym;
+ /* For PIC, disallow R_386_GOT32X without a base register
+ since we don't know what the GOT base is. Allow
+ R_386_GOT32 for existing object files. */
+ const char *name;
+
+ if (r_symndx < symtab_hdr->sh_info)
+ {
+ isym = bfd_sym_from_r_symndx (&htab->sym_cache, abfd,
+ r_symndx);
+ name = bfd_elf_sym_name (abfd, symtab_hdr, isym, NULL);
+ }
+ else
+ {
+ indx = r_symndx - symtab_hdr->sh_info;
+ h = elf_sym_hashes (abfd)[indx];
+ BFD_ASSERT (h != NULL);
+ name = h->root.root.string;
+ }
+
+ (*_bfd_error_handler)
+ (_("%B: direct GOT relocation R_386_GOT32X against `%s' without base register can not be used when making a shared object"),
+ abfd, name);
+ goto error_return;
+ }
+
+ opcode = bfd_get_8 (abfd, contents + roff - 2);
+
+ /* It is OK to convert mov to lea. */
+ if (opcode != 0x8b)
+ {
+ /* Only convert R_386_GOT32X relocation for call, jmp or
+ one of adc, add, and, cmp, or, sbb, sub, test, xor
+ instructions. */
+ if (r_type != R_386_GOT32X)
+ continue;
+
+ /* It is OK to convert indirect branch to direct branch. It
+ is OK to convert adc, add, and, cmp, or, sbb, sub, test,
+ xor only when PIC is false. */
+ if (opcode != 0xff && bfd_link_pic (link_info))
+ continue;
+ }
+ /* Try to convert R_386_GOT32 and R_386_GOT32X. Get the symbol
+ referred to by the reloc. */
+ if (r_symndx < symtab_hdr->sh_info)
+ {
isym = bfd_sym_from_r_symndx (&htab->sym_cache,
abfd, r_symndx);
- /* STT_GNU_IFUNC must keep R_386_GOT32 relocation. */
- if (ELF_ST_TYPE (isym->st_info) != STT_GNU_IFUNC
- && irel->r_offset >= 2
- && bfd_get_8 (abfd, contents + irel->r_offset - 2) == 0x8b)
- {
- bfd_put_8 (abfd, 0x8d, contents + irel->r_offset - 2);
- irel->r_info = ELF32_R_INFO (r_symndx, R_386_GOTOFF);
- if (local_got_refcounts != NULL
- && local_got_refcounts[r_symndx] > 0)
- local_got_refcounts[r_symndx] -= 1;
- changed_contents = TRUE;
- changed_relocs = TRUE;
- }
- continue;
+ /* STT_GNU_IFUNC must keep GOT32 relocations. */
+ if (ELF_ST_TYPE (isym->st_info) == STT_GNU_IFUNC)
+ continue;
+
+ h = NULL;
+ if (opcode == 0x0ff)
+ /* Convert "call/jmp *foo@GOT[(%reg)]". */
+ goto convert_branch;
+ else
+ /* Convert "mov foo@GOT[(%reg1)], %reg2",
+ "test %reg1, foo@GOT(%reg2)" and
+ "binop foo@GOT[(%reg1)], %reg2". */
+ goto convert_load;
}
indx = r_symndx - symtab_hdr->sh_info;
@@ -2813,22 +2900,147 @@ elf_i386_convert_mov_to_lea (bfd *abfd, asection *sec,
|| h->root.type == bfd_link_hash_warning)
h = (struct elf_link_hash_entry *) h->root.u.i.link;
- /* STT_GNU_IFUNC must keep R_386_GOT32 relocation. We also avoid
- optimizing _DYNAMIC since ld.so may use its link-time address. */
- if ((h->root.type == bfd_link_hash_defined
- || h->root.type == bfd_link_hash_defweak)
- && h->type != STT_GNU_IFUNC
- && h != htab->elf.hdynamic
- && SYMBOL_REFERENCES_LOCAL (link_info, h)
- && irel->r_offset >= 2
- && bfd_get_8 (abfd, contents + irel->r_offset - 2) == 0x8b)
+ /* STT_GNU_IFUNC must keep GOT32 relocations. */
+ if (h->type == STT_GNU_IFUNC)
+ continue;
+
+ if (opcode == 0xff)
+ {
+ /* We have "call/jmp *foo@GOT[(%reg)]". */
+ if ((h->root.type == bfd_link_hash_defined
+ || h->root.type == bfd_link_hash_defweak)
+ && SYMBOL_REFERENCES_LOCAL (link_info, h))
+ {
+ /* The function is locally defined. */
+convert_branch:
+ addend = bfd_get_32 (abfd, contents + roff);
+ /* Addend for R_386_GOT32X relocation must be 0. */
+ if (addend != 0)
+ continue;
+
+ /* Convert R_386_GOT32X to R_386_PC32. */
+ if (modrm == 0x15 || (modrm & 0xf8) == 0x90)
+ {
+ /* Convert to "nop call foo". ADDR_PREFIX_OPCODE
+ is a nop prefix. */
+ modrm = 0xe8;
+ nop = ADDR_PREFIX_OPCODE;
+ nop_offset = roff - 2;
+ }
+ else
+ {
+ /* Convert to "jmp foo nop". */
+ modrm = 0xe9;
+ nop = NOP_OPCODE;
+ nop_offset = roff + 3;
+ irel->r_offset -= 1;
+ }
+
+ bfd_put_8 (abfd, nop, contents + nop_offset);
+ bfd_put_8 (abfd, modrm, contents + irel->r_offset - 1);
+ /* When converting to PC-relative relocation, we
+ need to adjust addend by -4. */
+ bfd_put_32 (abfd, -4, contents + irel->r_offset);
+ irel->r_info = ELF32_R_INFO (r_symndx, R_386_PC32);
+
+ if (h)
+ {
+ if (h->got.refcount > 0)
+ h->got.refcount -= 1;
+ }
+ else
+ {
+ if (local_got_refcounts != NULL
+ && local_got_refcounts[r_symndx] > 0)
+ local_got_refcounts[r_symndx] -= 1;
+ }
+
+ changed_contents = TRUE;
+ changed_relocs = TRUE;
+ }
+ }
+ else
{
- bfd_put_8 (abfd, 0x8d, contents + irel->r_offset - 2);
- irel->r_info = ELF32_R_INFO (r_symndx, R_386_GOTOFF);
- if (h->got.refcount > 0)
- h->got.refcount -= 1;
- changed_contents = TRUE;
- changed_relocs = TRUE;
+ /* We have "mov foo@GOT[(%re1g)], %reg2",
+ "test %reg1, foo@GOT(%reg2)" and
+ "binop foo@GOT[(%reg1)], %reg2".
+
+ Avoid optimizing _DYNAMIC since ld.so may use its
+ link-time address. */
+ if (h == htab->elf.hdynamic)
+ continue;
+
+ if ((h->root.type == bfd_link_hash_defined
+ || h->root.type == bfd_link_hash_defweak)
+ && SYMBOL_REFERENCES_LOCAL (link_info, h))
+ {
+convert_load:
+ if (opcode == 0x8b)
+ {
+ /* Convert "mov foo@GOT(%reg1), %reg2" to
+ "lea foo@GOTOFF(%reg1), %reg2". */
+ if (r_type == R_386_GOT32X
+ && (baseless || !bfd_link_pic (link_info)))
+ {
+ r_type = R_386_32;
+ /* For R_386_32, convert
+ "lea foo@GOTOFF(%reg1), %reg2" to
+ "lea foo@GOT, %reg2". */
+ if (!baseless)
+ {
+ modrm = 0x5 | (modrm & 0x38);
+ bfd_put_8 (abfd, modrm, contents + roff - 1);
+ }
+ }
+ else
+ r_type = R_386_GOTOFF;
+ opcode = 0x8d;
+ }
+ else
+ {
+ /* Addend for R_386_GOT32X relocation must be 0. */
+ addend = bfd_get_32 (abfd, contents + roff);
+ if (addend != 0)
+ continue;
+
+ if (opcode == 0x85)
+ {
+ /* Convert "test %reg1, foo@GOT(%reg2)" to
+ "test $foo, %reg1". */
+ modrm = 0xc0 | (modrm & 0x38) >> 3;
+ opcode = 0xf7;
+ }
+ else
+ {
+ /* Convert "binop foo@GOT(%reg1), %reg2" to
+ "binop $foo, %reg2". */
+ modrm = (0xc0
+ | (modrm & 0x38) >> 3
+ | (opcode & 0x3c));
+ opcode = 0x81;
+ }
+ bfd_put_8 (abfd, modrm, contents + roff - 1);
+ r_type = R_386_32;
+ }
+
+ bfd_put_8 (abfd, opcode, contents + roff - 2);
+ irel->r_info = ELF32_R_INFO (r_symndx, r_type);
+
+ if (h)
+ {
+ if (h->got.refcount > 0)
+ h->got.refcount -= 1;
+ }
+ else
+ {
+ if (local_got_refcounts != NULL
+ && local_got_refcounts[r_symndx] > 0)
+ local_got_refcounts[r_symndx] -= 1;
+ }
+
+ changed_contents = TRUE;
+ changed_relocs = TRUE;
+ }
}
}
@@ -2914,7 +3126,7 @@ elf_i386_size_dynamic_sections (bfd *output_bfd, struct bfd_link_info *info)
{
struct elf_dyn_relocs *p;
- if (!elf_i386_convert_mov_to_lea (ibfd, s, info))
+ if (!elf_i386_convert_load (ibfd, s, info))
return FALSE;
for (p = ((struct elf_dyn_relocs *)
@@ -3664,6 +3876,7 @@ elf_i386_relocate_section (bfd *output_bfd,
goto do_relocation;
case R_386_GOT32:
+ case R_386_GOT32X:
base_got = htab->elf.sgot;
off = h->got.offset;
@@ -3741,7 +3954,61 @@ elf_i386_relocate_section (bfd *output_bfd,
eh = (struct elf_i386_link_hash_entry *) h;
switch (r_type)
{
+ case R_386_GOT32X:
+ /* Avoid optimizing _DYNAMIC since ld.so may use its
+ link-time address. */
+ if (h == htab->elf.hdynamic)
+ goto r_386_got32;
+
+ if (bfd_link_pic (info))
+ {
+ /* It is OK to convert mov to lea and convert indirect
+ branch to direct branch. It is OK to convert adc,
+ add, and, cmp, or, sbb, sub, test, xor only when PIC
+ is false. */
+ unsigned int opcode;
+ opcode = bfd_get_8 (abfd, contents + rel->r_offset - 2);
+ if (opcode != 0x8b && opcode != 0xff)
+ goto r_386_got32;
+ }
+
+ /* Resolve "mov GOT[(%reg)], %reg",
+ "call/jmp *GOT[(%reg)]", "test %reg, foo@GOT[(%reg)]"
+ and "binop foo@GOT[(%reg)], %reg". */
+ if (h == NULL
+ || (h->plt.offset == (bfd_vma) -1
+ && h->got.offset == (bfd_vma) -1)
+ || htab->elf.sgotplt == NULL)
+ abort ();
+
+ offplt = (htab->elf.sgotplt->output_section->vma
+ + htab->elf.sgotplt->output_offset);
+
+ /* It is relative to .got.plt section. */
+ if (h->got.offset != (bfd_vma) -1)
+ /* Use GOT entry. */
+ relocation = (htab->elf.sgot->output_section->vma
+ + htab->elf.sgot->output_offset
+ + h->got.offset - offplt);
+ else
+ /* Use GOTPLT entry. */
+ relocation = (h->plt.offset / plt_entry_size - 1 + 3) * 4;
+
+ if (!bfd_link_pic (info))
+ {
+ /* If not PIC, add the .got.plt section address for
+ baseless adressing. */
+ unsigned int modrm;
+ modrm = bfd_get_8 (abfd, contents + rel->r_offset - 1);
+ if ((modrm & 0xc7) == 0x5)
+ relocation += offplt;
+ }
+
+ unresolved_reloc = FALSE;
+ break;
+
case R_386_GOT32:
+r_386_got32:
/* Relocation is to the entry for this symbol in the global
offset table. */
if (htab->elf.sgot == NULL)
diff --git a/bfd/libbfd.h b/bfd/libbfd.h
index 9ae9ba2..3bf1400 100644
--- a/bfd/libbfd.h
+++ b/bfd/libbfd.h
@@ -1292,6 +1292,7 @@ static const char *const bfd_reloc_code_real_names[] = { "@@uninitialized@@",
"BFD_RELOC_386_TLS_DESC_CALL",
"BFD_RELOC_386_TLS_DESC",
"BFD_RELOC_386_IRELATIVE",
+ "BFD_RELOC_386_GOT32X",
"BFD_RELOC_X86_64_GOT32",
"BFD_RELOC_X86_64_PLT32",
"BFD_RELOC_X86_64_COPY",
diff --git a/bfd/reloc.c b/bfd/reloc.c
index 886c63e..c6e2807 100644
--- a/bfd/reloc.c
+++ b/bfd/reloc.c
@@ -2676,6 +2676,8 @@ ENUMX
BFD_RELOC_386_TLS_DESC
ENUMX
BFD_RELOC_386_IRELATIVE
+ENUMX
+ BFD_RELOC_386_GOT32X
ENUMDOC
i386/elf relocations
generated by cgit v1.1 at 2024-11-24 01:44:54 +0000