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[PATCH] x86: Remove func_pointer_refcount
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: binutils at sourceware dot org
- Date: Wed, 1 Nov 2017 09:56:05 -0700
- Subject: [PATCH] x86: Remove func_pointer_refcount
- Authentication-results: sourceware.org; auth=none
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
Since check_reloc is running after gc_sections, there is no need for
reference count. If a function pointer relocation can be resolved at
run-time, there is no need for PLT and it doesn't count as non-GOT/PLT
relocation. func_pointer_refcount can be removed.
* elf32-i386.c (elf_i386_check_relocs): Set plt.refcount to 1.
Don't use func_pointer_refcount. Don't set plt.refcount nor
non_got_ref for function pointer reference.
* elf64-x86-64.c (elf_x86_64_check_relocs): Likewise.
* elfxx-x86.c (elf_x86_allocate_dynrelocs): Don't use
func_pointer_refcount.
(_bfd_x86_elf_copy_indirect_symbol): Don't copy
func_pointer_refcount.
(_bfd_x86_elf_hide_symbol): Don't use func_pointer_refcount.
* elfxx-x86.h (GENERATE_DYNAMIC_RELOCATION_P): Likewise.
(elf_x86_link_hash_entry): Remove func_pointer_refcount.
---
bfd/elf32-i386.c | 37 +++++++++++++++++++++----------------
bfd/elf64-x86-64.c | 39 ++++++++++++++++++++++-----------------
bfd/elfxx-x86.c | 25 +++----------------------
bfd/elfxx-x86.h | 5 -----
4 files changed, 46 insertions(+), 60 deletions(-)
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 4b57b652ed..c9ff0c4bbf 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -1600,7 +1600,7 @@ elf_i386_check_relocs (bfd *abfd,
eh->zero_undefweak &= 0x2;
h->needs_plt = 1;
- h->plt.refcount += 1;
+ h->plt.refcount = 1;
break;
case R_386_SIZE32:
@@ -1751,20 +1751,7 @@ do_relocation:
&& (bfd_link_executable (info)
|| h->type == STT_GNU_IFUNC))
{
- /* If this reloc is in a read-only section, we might
- need a copy reloc. We can't check reliably at this
- stage whether the section is read-only, as input
- sections have not yet been mapped to output sections.
- Tentatively set the flag for now, and correct in
- adjust_dynamic_symbol. */
- h->non_got_ref = 1;
-
- /* We may need a .plt entry if the symbol is a function
- defined in a shared lib or is a STT_GNU_IFUNC function
- referenced from the code or read-only section. */
- if (!h->def_regular
- || (sec->flags & (SEC_CODE | SEC_READONLY)) != 0)
- h->plt.refcount += 1;
+ bfd_boolean func_pointer_ref = FALSE;
if (r_type == R_386_PC32)
{
@@ -1790,7 +1777,25 @@ do_relocation:
/* R_386_32 can be resolved at run-time. */
if (r_type == R_386_32
&& (sec->flags & SEC_READONLY) == 0)
- eh->func_pointer_refcount += 1;
+ func_pointer_ref = TRUE;
+ }
+
+ if (!func_pointer_ref)
+ {
+ /* If this reloc is in a read-only section, we might
+ need a copy reloc. We can't check reliably at this
+ stage whether the section is read-only, as input
+ sections have not yet been mapped to output sections.
+ Tentatively set the flag for now, and correct in
+ adjust_dynamic_symbol. */
+ h->non_got_ref = 1;
+
+ /* We may need a .plt entry if the symbol is a function
+ defined in a shared lib or is a function referenced
+ from the code or read-only section. */
+ if (!h->def_regular
+ || (sec->flags & (SEC_CODE | SEC_READONLY)) != 0)
+ h->plt.refcount = 1;
}
}
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index 6a5159d4b0..d0af4ba4f6 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -2067,7 +2067,7 @@ elf_x86_64_check_relocs (bfd *abfd, struct bfd_link_info *info,
eh->zero_undefweak &= 0x2;
h->needs_plt = 1;
- h->plt.refcount += 1;
+ h->plt.refcount = 1;
break;
case R_X86_64_PLTOFF64:
@@ -2076,7 +2076,7 @@ elf_x86_64_check_relocs (bfd *abfd, struct bfd_link_info *info,
if (h != NULL)
{
h->needs_plt = 1;
- h->plt.refcount += 1;
+ h->plt.refcount = 1;
}
goto create_got;
@@ -2124,20 +2124,7 @@ pointer:
&& (bfd_link_executable (info)
|| h->type == STT_GNU_IFUNC))
{
- /* If this reloc is in a read-only section, we might
- need a copy reloc. We can't check reliably at this
- stage whether the section is read-only, as input
- sections have not yet been mapped to output sections.
- Tentatively set the flag for now, and correct in
- adjust_dynamic_symbol. */
- h->non_got_ref = 1;
-
- /* We may need a .plt entry if the symbol is a function
- defined in a shared lib or is a STT_GNU_IFUNC function
- referenced from the code or read-only section. */
- if (!h->def_regular
- || (sec->flags & (SEC_CODE | SEC_READONLY)) != 0)
- h->plt.refcount += 1;
+ bfd_boolean func_pointer_ref = FALSE;
if (r_type == R_X86_64_PC32)
{
@@ -2159,7 +2146,25 @@ pointer:
|| (!ABI_64_P (abfd)
&& (r_type == R_X86_64_32
|| r_type == R_X86_64_32S))))
- eh->func_pointer_refcount += 1;
+ func_pointer_ref = TRUE;
+ }
+
+ if (!func_pointer_ref)
+ {
+ /* If this reloc is in a read-only section, we might
+ need a copy reloc. We can't check reliably at this
+ stage whether the section is read-only, as input
+ sections have not yet been mapped to output sections.
+ Tentatively set the flag for now, and correct in
+ adjust_dynamic_symbol. */
+ h->non_got_ref = 1;
+
+ /* We may need a .plt entry if the symbol is a function
+ defined in a shared lib or is a function referenced
+ from the code or read-only section. */
+ if (!h->def_regular
+ || (sec->flags & (SEC_CODE | SEC_READONLY)) != 0)
+ h->plt.refcount = 1;
}
}
diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c
index f4466ebd59..df21d4eb86 100644
--- a/bfd/elfxx-x86.c
+++ b/bfd/elfxx-x86.c
@@ -108,11 +108,6 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
resolved_to_zero = UNDEFINED_WEAK_RESOLVED_TO_ZERO (info, eh);
- /* Clear the reference count of function pointer relocations if
- symbol isn't a normal function. */
- if (h->type != STT_FUNC)
- eh->func_pointer_refcount = 0;
-
/* We can't use the GOT PLT if pointer equality is needed since
finish_dynamic_symbol won't clear symbol value and the dynamic
linker won't update the GOT slot. We will get into an infinite
@@ -162,15 +157,11 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
/* Don't create the PLT entry if there are only function pointer
relocations which can be resolved at run-time. */
else if (htab->elf.dynamic_sections_created
- && (h->plt.refcount > eh->func_pointer_refcount
+ && (h->plt.refcount > 0
|| eh->plt_got.refcount > 0))
{
bfd_boolean use_plt_got = eh->plt_got.refcount > 0;
- /* Clear the reference count of function pointer relocations
- if PLT is used. */
- eh->func_pointer_refcount = 0;
-
/* Make sure this symbol is output as a dynamic symbol.
Undefined weak syms won't yet be marked as dynamic. */
if (h->dynindx == -1
@@ -488,7 +479,6 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
pointer initialization. */
if ((!h->non_got_ref
- || eh->func_pointer_refcount > 0
|| (h->root.type == bfd_link_hash_undefweak
&& !resolved_to_zero))
&& ((h->def_dynamic
@@ -513,7 +503,6 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
}
eh->dyn_relocs = NULL;
- eh->func_pointer_refcount = 0;
keep: ;
}
@@ -1643,15 +1632,7 @@ _bfd_x86_elf_copy_indirect_symbol (struct bfd_link_info *info,
dir->pointer_equality_needed |= ind->pointer_equality_needed;
}
else
- {
- if (eind->func_pointer_refcount > 0)
- {
- edir->func_pointer_refcount += eind->func_pointer_refcount;
- eind->func_pointer_refcount = 0;
- }
-
- _bfd_elf_link_hash_copy_indirect (info, dir, ind);
- }
+ _bfd_elf_link_hash_copy_indirect (info, dir, ind);
}
/* Remove undefined weak symbol from the dynamic symbol table if it
@@ -1900,7 +1881,7 @@ _bfd_x86_elf_hide_symbol (struct bfd_link_info *info,
weak symbol dynamic so that PC relative branch to the undefined
weak symbol will land to address 0. */
struct elf_x86_link_hash_entry *eh = elf_x86_hash_entry (h);
- if (h->plt.refcount > eh->func_pointer_refcount
+ if (h->plt.refcount > 0
|| eh->plt_got.refcount > 0)
return;
}
diff --git a/bfd/elfxx-x86.h b/bfd/elfxx-x86.h
index 8d2a7317eb..fb57d4377a 100644
--- a/bfd/elfxx-x86.h
+++ b/bfd/elfxx-x86.h
@@ -133,7 +133,6 @@
&& (EH) != NULL \
&& (EH)->elf.dynindx != -1 \
&& (!(EH)->elf.non_got_ref \
- || (EH)->func_pointer_refcount > 0 \
|| ((EH)->elf.root.type == bfd_link_hash_undefweak \
&& !(RESOLVED_TO_ZERO))) \
&& (((EH)->elf.def_dynamic && !(EH)->elf.def_regular) \
@@ -268,10 +267,6 @@ struct elf_x86_link_hash_entry
is only used by x86-64. */
unsigned int needs_copy : 1;
- /* Reference count of C/C++ function pointer relocations in read-write
- section which can be resolved at run-time. */
- bfd_signed_vma func_pointer_refcount;
-
/* Information about the GOT PLT entry. Filled when there are both
GOT and PLT relocations against the same function. */
union gotplt_union plt_got;
--
2.13.6