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Re: PATCH: PR ld/14956: Unnecessary R_X86_64_NONE
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Binutils <binutils at sourceware dot org>
- Date: Thu, 20 Dec 2012 10:53:07 -0800
- Subject: Re: PATCH: PR ld/14956: Unnecessary R_X86_64_NONE
- References: <20121213210852.GA6032@intel.com>
On Thu, Dec 13, 2012 at 1:08 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> Hi,
>
> I checked in this patch to check local IFUNC calls so that we can
> avoid unnecessary R_*_NONE relocations.
>
>
> H.J.
> ----
> diff --git a/bfd/ChangeLog b/bfd/ChangeLog
> index 5c4ace1..1ff8574 100644
> --- a/bfd/ChangeLog
> +++ b/bfd/ChangeLog
> @@ -1,3 +1,10 @@
> +2012-12-13 H.J. Lu <hongjiu.lu@intel.com>
> +
> + PR ld/14956
> + * elf32-i386.c (elf_i386_adjust_dynamic_symbol): Check local
> + IFUNC calls.
> + * elf64-x86-64.c (elf_x86_64_adjust_dynamic_symbol): Likewise.
> +
> 2012-12-10 Edgar E. Iglesias <edgar.iglesias@gmail.com>
>
> * reloc.c (MICROBLAZE): Document new relocations
> diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
> index 1b04a6e..bb41302 100644
> --- a/bfd/elf32-i386.c
> +++ b/bfd/elf32-i386.c
> @@ -2066,10 +2066,39 @@ elf_i386_adjust_dynamic_symbol (struct bfd_link_info *info,
> {
> struct elf_i386_link_hash_table *htab;
> asection *s;
> + struct elf_i386_link_hash_entry *eh;
> + struct elf_dyn_relocs *p;
>
> /* STT_GNU_IFUNC symbol must go through PLT. */
> if (h->type == STT_GNU_IFUNC)
> {
> + /* Check local STT_GNU_IFUNC calls. */
> + if (h->ref_regular
> + && SYMBOL_CALLS_LOCAL (info, h))
> + {
> + bfd_size_type pc_count = 0;
> + struct elf_dyn_relocs **pp;
> +
> + eh = (struct elf_i386_link_hash_entry *) h;
> + for (pp = &eh->dyn_relocs; (p = *pp) != NULL; )
> + {
> + pc_count += p->pc_count;
> + p->count -= p->pc_count;
> + p->pc_count = 0;
> + if (p->count == 0)
> + *pp = p->next;
> + else
> + pp = &p->next;
> + }
> +
> + if (pc_count)
> + {
> + h->needs_plt = 1;
> + h->plt.refcount += 1;
> + h->non_got_ref = 1;
> + }
> + }
> +
> if (h->plt.refcount <= 0)
> {
> h->plt.offset = (bfd_vma) -1;
> @@ -2155,9 +2184,6 @@ elf_i386_adjust_dynamic_symbol (struct bfd_link_info *info,
> if (ELIMINATE_COPY_RELOCS
> && !get_elf_i386_backend_data (info->output_bfd)->is_vxworks)
> {
> - struct elf_i386_link_hash_entry * eh;
> - struct elf_dyn_relocs *p;
> -
> eh = (struct elf_i386_link_hash_entry *) h;
> for (p = eh->dyn_relocs; p != NULL; p = p->next)
> {
> diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
> index d58384f..ec38ddc 100644
> --- a/bfd/elf64-x86-64.c
> +++ b/bfd/elf64-x86-64.c
> @@ -2134,10 +2134,39 @@ elf_x86_64_adjust_dynamic_symbol (struct bfd_link_info *info,
> {
> struct elf_x86_64_link_hash_table *htab;
> asection *s;
> + struct elf_x86_64_link_hash_entry *eh;
> + struct elf_dyn_relocs *p;
>
> /* STT_GNU_IFUNC symbol must go through PLT. */
> if (h->type == STT_GNU_IFUNC)
> {
> + /* Check local STT_GNU_IFUNC calls. */
> + if (h->ref_regular
> + && SYMBOL_CALLS_LOCAL (info, h))
> + {
> + bfd_size_type pc_count = 0;
> + struct elf_dyn_relocs **pp;
> +
> + eh = (struct elf_x86_64_link_hash_entry *) h;
> + for (pp = &eh->dyn_relocs; (p = *pp) != NULL; )
> + {
> + pc_count += p->pc_count;
> + p->count -= p->pc_count;
> + p->pc_count = 0;
> + if (p->count == 0)
> + *pp = p->next;
> + else
> + pp = &p->next;
> + }
> +
> + if (pc_count)
> + {
> + h->needs_plt = 1;
> + h->plt.refcount += 1;
> + h->non_got_ref = 1;
> + }
> + }
> +
> if (h->plt.refcount <= 0)
> {
> h->plt.offset = (bfd_vma) -1;
> @@ -2214,9 +2243,6 @@ elf_x86_64_adjust_dynamic_symbol (struct bfd_link_info *info,
>
> if (ELIMINATE_COPY_RELOCS)
> {
> - struct elf_x86_64_link_hash_entry * eh;
> - struct elf_dyn_relocs *p;
> -
> eh = (struct elf_x86_64_link_hash_entry *) h;
> for (p = eh->dyn_relocs; p != NULL; p = p->next)
> {
> diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
> index b534021..994ee04 100644
> --- a/ld/testsuite/ChangeLog
> +++ b/ld/testsuite/ChangeLog
> @@ -1,3 +1,19 @@
> +2012-12-13 H.J. Lu <hongjiu.lu@intel.com>
> +
> + PR ld/14956
> + * ld-ifunc/ifunc-14-i386.d: Renamed to ...
> + * ld-ifunc/ifunc-14a-i386.d: This.
> +
> + * ld-ifunc/ifunc-14-x86-64.d: Renamed to ...
> + * ld-ifunc/ifunc-14a-x86-64.d: This.
> +
> + * ld-ifunc/ifunc-14b-i386.d: New file.
> + * ld-ifunc/ifunc-14b-x86-64.d: Likewise.
> + * ld-ifunc/ifunc-14c-i386.d: Likewise.
> + * ld-ifunc/ifunc-14c-x86-64.d: Likewise.
> + * ld-ifunc/ifunc-14d-i386.d: Likewise.
> + * ld-ifunc/ifunc-14d-x86-64.d: Likewise.
> +
> 2012-12-07 H.J. Lu <hongjiu.lu@intel.com>
>
> * ld-elf/pr14926.d: Use "readelf -S --wide".
> diff --git a/ld/testsuite/ld-ifunc/ifunc-14-i386.d b/ld/testsuite/ld-ifunc/ifunc-14-i386.d
> deleted file mode 100644
> index 0edc9fb..0000000
> --- a/ld/testsuite/ld-ifunc/ifunc-14-i386.d
> +++ /dev/null
> @@ -1,11 +0,0 @@
> -#source: ifunc-14a.s
> -#source: ifunc-14b.s
> -#ld: -shared -m elf_i386 -z nocombreloc
> -#as: --32
> -#readelf: -d --wide
> -#target: x86_64-*-* i?86-*-*
> -
> -#failif
> -#...
> -.*\(TEXTREL\).*
> -#...
> diff --git a/ld/testsuite/ld-ifunc/ifunc-14-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-14-x86-64.d
> deleted file mode 100644
> index 2c4ebbb..0000000
> --- a/ld/testsuite/ld-ifunc/ifunc-14-x86-64.d
> +++ /dev/null
> @@ -1,11 +0,0 @@
> -#source: ifunc-14a.s
> -#source: ifunc-14b.s
> -#ld: -shared -m elf_x86_64 -z nocombreloc
> -#as: --64
> -#readelf: -d
> -#target: x86_64-*-*
> -
> -#failif
> -#...
> -.*\(TEXTREL\).*
> -#...
> diff --git a/ld/testsuite/ld-ifunc/ifunc-14a-i386.d b/ld/testsuite/ld-ifunc/ifunc-14a-i386.d
> new file mode 100644
> index 0000000..0edc9fb
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-14a-i386.d
> @@ -0,0 +1,11 @@
> +#source: ifunc-14a.s
> +#source: ifunc-14b.s
> +#ld: -shared -m elf_i386 -z nocombreloc
> +#as: --32
> +#readelf: -d --wide
> +#target: x86_64-*-* i?86-*-*
> +
> +#failif
> +#...
> +.*\(TEXTREL\).*
> +#...
> diff --git a/ld/testsuite/ld-ifunc/ifunc-14a-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-14a-x86-64.d
> new file mode 100644
> index 0000000..2c4ebbb
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-14a-x86-64.d
> @@ -0,0 +1,11 @@
> +#source: ifunc-14a.s
> +#source: ifunc-14b.s
> +#ld: -shared -m elf_x86_64 -z nocombreloc
> +#as: --64
> +#readelf: -d
> +#target: x86_64-*-*
> +
> +#failif
> +#...
> +.*\(TEXTREL\).*
> +#...
> diff --git a/ld/testsuite/ld-ifunc/ifunc-14b-i386.d b/ld/testsuite/ld-ifunc/ifunc-14b-i386.d
> new file mode 100644
> index 0000000..948237d
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-14b-i386.d
> @@ -0,0 +1,11 @@
> +#source: ifunc-14b.s
> +#source: ifunc-14a.s
> +#ld: -shared -m elf_i386 -z nocombreloc
> +#as: --32
> +#readelf: -d --wide
> +#target: x86_64-*-* i?86-*-*
> +
> +#failif
> +#...
> +.*\(TEXTREL\).*
> +#...
> diff --git a/ld/testsuite/ld-ifunc/ifunc-14b-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-14b-x86-64.d
> new file mode 100644
> index 0000000..cc1f5ae
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-14b-x86-64.d
> @@ -0,0 +1,11 @@
> +#source: ifunc-14b.s
> +#source: ifunc-14a.s
> +#ld: -shared -m elf_x86_64 -z nocombreloc
> +#as: --64
> +#readelf: -d
> +#target: x86_64-*-*
> +
> +#failif
> +#...
> +.*\(TEXTREL\).*
> +#...
> diff --git a/ld/testsuite/ld-ifunc/ifunc-14c-i386.d b/ld/testsuite/ld-ifunc/ifunc-14c-i386.d
> new file mode 100644
> index 0000000..ca360a3
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-14c-i386.d
> @@ -0,0 +1,11 @@
> +#source: ifunc-14a.s
> +#source: ifunc-14b.s
> +#ld: -shared -m elf_i386 -z nocombreloc
> +#as: --32
> +#readelf: -r --wide
> +#target: x86_64-*-* i?86-*-*
> +
> +#failif
> +#...
> +.* +R_386_NONE +.*
> +#...
> diff --git a/ld/testsuite/ld-ifunc/ifunc-14c-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-14c-x86-64.d
> new file mode 100644
> index 0000000..76bfa84
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-14c-x86-64.d
> @@ -0,0 +1,11 @@
> +#source: ifunc-14a.s
> +#source: ifunc-14b.s
> +#ld: -shared -m elf_x86_64 -z nocombreloc
> +#as: --64
> +#readelf: -r --wide
> +#target: x86_64-*-*
> +
> +#failif
> +#...
> +.* +R_X86_64_NONE +.*
> +#...
> diff --git a/ld/testsuite/ld-ifunc/ifunc-14d-i386.d b/ld/testsuite/ld-ifunc/ifunc-14d-i386.d
> new file mode 100644
> index 0000000..2327278
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-14d-i386.d
> @@ -0,0 +1,11 @@
> +#source: ifunc-14b.s
> +#source: ifunc-14a.s
> +#ld: -shared -m elf_i386 -z nocombreloc
> +#as: --32
> +#readelf: -r --wide
> +#target: x86_64-*-* i?86-*-*
> +
> +#failif
> +#...
> +.* +R_386_NONE +.*
> +#...
> diff --git a/ld/testsuite/ld-ifunc/ifunc-14d-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-14d-x86-64.d
> new file mode 100644
> index 0000000..789584b
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-14d-x86-64.d
> @@ -0,0 +1,11 @@
> +#source: ifunc-14b.s
> +#source: ifunc-14a.s
> +#ld: -shared -m elf_x86_64 -z nocombreloc
> +#as: --64
> +#readelf: -r --wide
> +#target: x86_64-*-*
> +
> +#failif
> +#...
> +.* +R_X86_64_NONE +.*
> +#...
I also checked it into 2.23 branch.
--
H.J.