x86-64: Use __glibc_likely/__glibc_likely in dl-machine.h
Commit Message
On Fri, Feb 2, 2018 at 9:42 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> OK for master?
>
> H.J.
> ---
> * sysdeps/x86_64/dl-machine.h (elf_machine_rela): Replace
> __builtin_expect with __glibc_likely and __glibc_likely.
> (elf_machine_lazy_rel): Likewise.
> ---
> sysdeps/x86_64/dl-machine.h | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h
> index f525600071..5d45ca5342 100644
> --- a/sysdeps/x86_64/dl-machine.h
> +++ b/sysdeps/x86_64/dl-machine.h
> @@ -310,10 +310,9 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
> : (ElfW(Addr)) sym_map->l_addr + sym->st_value);
>
> if (sym != NULL
> - && __builtin_expect (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC,
> - 0)
> - && __builtin_expect (sym->st_shndx != SHN_UNDEF, 1)
> - && __builtin_expect (!skip_ifunc, 1))
> + && __glibc_unlikely (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC)
> + && __glibc_likely (sym->st_shndx != SHN_UNDEF)
> + && __glibc_likely (!skip_ifunc))
> {
> # ifndef RTLD_BOOTSTRAP
> if (sym_map != map
> @@ -500,8 +499,8 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
> break;
> memcpy (reloc_addr_arg, (void *) value,
> MIN (sym->st_size, refsym->st_size));
> - if (__builtin_expect (sym->st_size > refsym->st_size, 0)
> - || (__builtin_expect (sym->st_size < refsym->st_size, 0)
> + if (__glibc_unlikely (sym->st_size > refsym->st_size)
> + || (__glibc_unlikely (sym->st_size < refsym->st_size)
> && GLRO(dl_verbose)))
> {
> fmt = "\
> @@ -554,7 +553,8 @@ elf_machine_lazy_rel (struct link_map *map,
> /* Check for unexpected PLT reloc type. */
> if (__glibc_likely (r_type == R_X86_64_JUMP_SLOT))
> {
> - if (__builtin_expect (map->l_mach.plt, 0) == 0)
> + /* Prelinked has been deprecated. */
> + if (__glibc_likely (map->l_mach.plt == 0))
> *reloc_addr += l_addr;
> else
> *reloc_addr =
> --
> 2.14.3
>
This is what I am checking in.
Comments
On 05/02/18 12:06, H.J. Lu wrote:
> - if (__builtin_expect (map->l_mach.plt, 0) == 0)
> + /* Prelinked has been deprecated. */
> + if (__glibc_likely (map->l_mach.plt == 0))
do you know about an email thread/documentation on deprecating prelinking?
(i'd like to have something to point users to when they ask for it)
On 05/02/2018 10:06, H.J. Lu wrote:
> On Fri, Feb 2, 2018 at 9:42 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>> OK for master?
>>
>> H.J.
>> ---
>> * sysdeps/x86_64/dl-machine.h (elf_machine_rela): Replace
>> __builtin_expect with __glibc_likely and __glibc_likely.
>> (elf_machine_lazy_rel): Likewise.
>> ---
>> sysdeps/x86_64/dl-machine.h | 14 +++++++-------
>> 1 file changed, 7 insertions(+), 7 deletions(-)
>>
>> diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h
>> index f525600071..5d45ca5342 100644
>> --- a/sysdeps/x86_64/dl-machine.h
>> +++ b/sysdeps/x86_64/dl-machine.h
>> @@ -310,10 +310,9 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
>> : (ElfW(Addr)) sym_map->l_addr + sym->st_value);
>>
>> if (sym != NULL
>> - && __builtin_expect (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC,
>> - 0)
>> - && __builtin_expect (sym->st_shndx != SHN_UNDEF, 1)
>> - && __builtin_expect (!skip_ifunc, 1))
>> + && __glibc_unlikely (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC)
>> + && __glibc_likely (sym->st_shndx != SHN_UNDEF)
>> + && __glibc_likely (!skip_ifunc))
>> {
>> # ifndef RTLD_BOOTSTRAP
>> if (sym_map != map
>> @@ -500,8 +499,8 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
>> break;
>> memcpy (reloc_addr_arg, (void *) value,
>> MIN (sym->st_size, refsym->st_size));
>> - if (__builtin_expect (sym->st_size > refsym->st_size, 0)
>> - || (__builtin_expect (sym->st_size < refsym->st_size, 0)
>> + if (__glibc_unlikely (sym->st_size > refsym->st_size)
>> + || (__glibc_unlikely (sym->st_size < refsym->st_size)
>> && GLRO(dl_verbose)))
>> {
>> fmt = "\
>> @@ -554,7 +553,8 @@ elf_machine_lazy_rel (struct link_map *map,
>> /* Check for unexpected PLT reloc type. */
>> if (__glibc_likely (r_type == R_X86_64_JUMP_SLOT))
>> {
>> - if (__builtin_expect (map->l_mach.plt, 0) == 0)
Thanks for changing it, these kind of construction with __builtin_expect is
confusing to read.
>> + /* Prelinked has been deprecated. */
>> + if (__glibc_likely (map->l_mach.plt == 0))
>> *reloc_addr += l_addr;
>> else
>> *reloc_addr =
>> --
>> 2.14.3
>>
>
> This is what I am checking in.
Seems straightforward enough, LGTM.
On Mon, Feb 5, 2018 at 4:11 AM, Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
> On 05/02/18 12:06, H.J. Lu wrote:
>>
>> - if (__builtin_expect (map->l_mach.plt, 0) == 0)
>> + /* Prelinked has been deprecated. */
>> + if (__glibc_likely (map->l_mach.plt == 0))
>
>
> do you know about an email thread/documentation on deprecating prelinking?
> (i'd like to have something to point users to when they ask for it)
https://lwn.net/Articles/341244/
https://pagure.io/fesco/issue/1183
https://stackoverflow.com/questions/2040256/is-prelinking-on-linux-for-shared-libraries-any-good-proven
https://serverfault.com/questions/39500/is-there-a-point-in-using-prelink-anymore
prelink package has been removed from Fedora a while back.
From 84fb880a14b55e3212826d9b03b78a372306dfa6 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 2 Feb 2018 09:40:02 -0800
Subject: [PATCH] x86-64: Use __glibc_likely/__glibc_likely in dl-machine.h
The differences in elf/dl-reloc.os are
@@ -1129,7 +1129,7 @@ _dl_relocate_object:
leaq __PRETTY_FUNCTION__.9767(%rip), %rcx
leaq .LC11(%rip), %rsi
leaq .LC12(%rip), %rdi
- movl $540, %edx
+ movl $539, %edx
call __GI___assert_fail
.p2align 4,,10
.p2align 3
* sysdeps/x86_64/dl-machine.h (elf_machine_rela): Replace
__builtin_expect with __glibc_likely and __glibc_likely.
(elf_machine_lazy_rel): Likewise.
---
sysdeps/x86_64/dl-machine.h | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
@@ -310,10 +310,9 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
: (ElfW(Addr)) sym_map->l_addr + sym->st_value);
if (sym != NULL
- && __builtin_expect (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC,
- 0)
- && __builtin_expect (sym->st_shndx != SHN_UNDEF, 1)
- && __builtin_expect (!skip_ifunc, 1))
+ && __glibc_unlikely (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC)
+ && __glibc_likely (sym->st_shndx != SHN_UNDEF)
+ && __glibc_likely (!skip_ifunc))
{
# ifndef RTLD_BOOTSTRAP
if (sym_map != map
@@ -500,8 +499,8 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
break;
memcpy (reloc_addr_arg, (void *) value,
MIN (sym->st_size, refsym->st_size));
- if (__builtin_expect (sym->st_size > refsym->st_size, 0)
- || (__builtin_expect (sym->st_size < refsym->st_size, 0)
+ if (__glibc_unlikely (sym->st_size > refsym->st_size)
+ || (__glibc_unlikely (sym->st_size < refsym->st_size)
&& GLRO(dl_verbose)))
{
fmt = "\
@@ -554,7 +553,8 @@ elf_machine_lazy_rel (struct link_map *map,
/* Check for unexpected PLT reloc type. */
if (__glibc_likely (r_type == R_X86_64_JUMP_SLOT))
{
- if (__builtin_expect (map->l_mach.plt, 0) == 0)
+ /* Prelinked has been deprecated. */
+ if (__glibc_likely (map->l_mach.plt == 0))
*reloc_addr += l_addr;
else
*reloc_addr =
--
2.14.3