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Re: PATCH: PR ld/14968: Missing R_*_IRELATIVE relocation
On Sun, Dec 16, 2012 at 12:35 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> On Thu, Dec 13, 2012 at 01:08:52PM -0800, H.J. Lu 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;
>
> The above patch has a hole. All local IFUNC references, including
> non-call references, must go though local PLT. I checked in this
> patch to fix it.
>
>
> H.J.
> ----
> diff --git a/bfd/ChangeLog b/bfd/ChangeLog
> index 87cc9d7..070acb4 100644
> --- a/bfd/ChangeLog
> +++ b/bfd/ChangeLog
> @@ -1,6 +1,13 @@
> +2012-12-16 H.J. Lu <hongjiu.lu@intel.com>
> +
> + PR ld/14968
> + * elf32-i386.c (elf_i386_adjust_dynamic_symbol): Also check
> + local IFUNC references.
> + * elf64-x86-64.c (elf_x86_64_adjust_dynamic_symbol): Likewise.
> +
> 2012-12-14 Tom Tromey <tromey@redhat.com>
>
> - * elf.c (elfcore_grok_note) <NT_FILE>: New case.
> + * elf.c (elfcore_grok_note) <NT_FILE>: New case.
>
> 2012-12-13 H.J. Lu <hongjiu.lu@intel.com>
>
> diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
> index bb41302..a188cec 100644
> --- a/bfd/elf32-i386.c
> +++ b/bfd/elf32-i386.c
> @@ -2072,11 +2072,12 @@ elf_i386_adjust_dynamic_symbol (struct bfd_link_info *info,
> /* STT_GNU_IFUNC symbol must go through PLT. */
> if (h->type == STT_GNU_IFUNC)
> {
> - /* Check local STT_GNU_IFUNC calls. */
> + /* All local STT_GNU_IFUNC references must be treate as local
> + calls via local PLT. */
> if (h->ref_regular
> && SYMBOL_CALLS_LOCAL (info, h))
> {
> - bfd_size_type pc_count = 0;
> + bfd_size_type pc_count = 0, count = 0;
> struct elf_dyn_relocs **pp;
>
> eh = (struct elf_i386_link_hash_entry *) h;
> @@ -2085,13 +2086,14 @@ elf_i386_adjust_dynamic_symbol (struct bfd_link_info *info,
> pc_count += p->pc_count;
> p->count -= p->pc_count;
> p->pc_count = 0;
> + count += p->count;
> if (p->count == 0)
> *pp = p->next;
> else
> pp = &p->next;
> }
>
> - if (pc_count)
> + if (pc_count || count)
> {
> h->needs_plt = 1;
> h->plt.refcount += 1;
> diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
> index ec38ddc..283681c 100644
> --- a/bfd/elf64-x86-64.c
> +++ b/bfd/elf64-x86-64.c
> @@ -2140,11 +2140,12 @@ elf_x86_64_adjust_dynamic_symbol (struct bfd_link_info *info,
> /* STT_GNU_IFUNC symbol must go through PLT. */
> if (h->type == STT_GNU_IFUNC)
> {
> - /* Check local STT_GNU_IFUNC calls. */
> + /* All local STT_GNU_IFUNC references must be treate as local
> + calls via local PLT. */
> if (h->ref_regular
> && SYMBOL_CALLS_LOCAL (info, h))
> {
> - bfd_size_type pc_count = 0;
> + bfd_size_type pc_count = 0, count = 0;
> struct elf_dyn_relocs **pp;
>
> eh = (struct elf_x86_64_link_hash_entry *) h;
> @@ -2153,13 +2154,14 @@ elf_x86_64_adjust_dynamic_symbol (struct bfd_link_info *info,
> pc_count += p->pc_count;
> p->count -= p->pc_count;
> p->pc_count = 0;
> + count += p->count;
> if (p->count == 0)
> *pp = p->next;
> else
> pp = &p->next;
> }
>
> - if (pc_count)
> + if (pc_count || count)
> {
> h->needs_plt = 1;
> h->plt.refcount += 1;
> diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
> index 7ae4014..7a2cb17 100644
> --- a/ld/testsuite/ChangeLog
> +++ b/ld/testsuite/ChangeLog
> @@ -1,3 +1,19 @@
> +2012-12-16 H.J. Lu <hongjiu.lu@intel.com>
> +
> + PR ld/14968
> + * ld-ifunc/ifunc-18a-i386.d: New file.
> + * ld-ifunc/ifunc-18a-x86-64.d: Likewise.
> + * ld-ifunc/ifunc-18a.s: Likewise.
> + * ld-ifunc/ifunc-18b-i386.d: Likewise.
> + * ld-ifunc/ifunc-18b-x86-64.d: Likewise.
> + * ld-ifunc/ifunc-18b.s: Likewise.
> + * ld-ifunc/ifunc-19a-i386.d: Likewise.
> + * ld-ifunc/ifunc-19a-x86-64.d: Likewise.
> + * ld-ifunc/ifunc-19a.s: Likewise.
> + * ld-ifunc/ifunc-19b-i386.d: Likewise.
> + * ld-ifunc/ifunc-19b-x86-64.d: Likewise.
> + * ld-ifunc/ifunc-19b.s: Likewise.
> +
> 2012-12-15 Thomas Schwinge <thomas@codesourcery.com>
>
> * ld-elf/elf.exp (stack exec, stack size): Run for any GNU target.
> diff --git a/ld/testsuite/ld-ifunc/ifunc-18a-i386.d b/ld/testsuite/ld-ifunc/ifunc-18a-i386.d
> new file mode 100644
> index 0000000..10490b1
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-18a-i386.d
> @@ -0,0 +1,15 @@
> +#source: ifunc-18a.s
> +#source: ifunc-18b.s
> +#ld: -shared -m elf_i386 -z nocombreloc
> +#as: --32
> +#readelf: -r --wide
> +#target: x86_64-*-* i?86-*-*
> +
> +Relocation section '.rel.ifunc' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]*
> +
> +Relocation section '.rel.plt' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]*
> diff --git a/ld/testsuite/ld-ifunc/ifunc-18a-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-18a-x86-64.d
> new file mode 100644
> index 0000000..0d600eb
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-18a-x86-64.d
> @@ -0,0 +1,15 @@
> +#source: ifunc-18a.s
> +#source: ifunc-18b.s
> +#as: --64
> +#ld: -shared -melf_x86_64 -z nocombreloc
> +#readelf: -r --wide
> +#target: x86_64-*-*
> +
> +Relocation section '.rela.ifunc' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]*
> +
> +Relocation section '.rela.plt' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]*
> diff --git a/ld/testsuite/ld-ifunc/ifunc-18a.s b/ld/testsuite/ld-ifunc/ifunc-18a.s
> new file mode 100644
> index 0000000..c29c121
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-18a.s
> @@ -0,0 +1,5 @@
> + .section .data.rel,"aw",@progbits
> + .globl foo_ptrt
> + .type foo_ptr, @object
> +foo_ptr:
> + .dc.a foo
> diff --git a/ld/testsuite/ld-ifunc/ifunc-18b-i386.d b/ld/testsuite/ld-ifunc/ifunc-18b-i386.d
> new file mode 100644
> index 0000000..a5eda94
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-18b-i386.d
> @@ -0,0 +1,15 @@
> +#source: ifunc-18b.s
> +#source: ifunc-18a.s
> +#ld: -shared -m elf_i386 -z nocombreloc
> +#as: --32
> +#readelf: -r --wide
> +#target: x86_64-*-* i?86-*-*
> +
> +Relocation section '.rel.ifunc' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]*
> +
> +Relocation section '.rel.plt' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]*
> diff --git a/ld/testsuite/ld-ifunc/ifunc-18b-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-18b-x86-64.d
> new file mode 100644
> index 0000000..8dfebfb
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-18b-x86-64.d
> @@ -0,0 +1,15 @@
> +#source: ifunc-18b.s
> +#source: ifunc-18a.s
> +#as: --64
> +#ld: -shared -melf_x86_64 -z nocombreloc
> +#readelf: -r --wide
> +#target: x86_64-*-*
> +
> +Relocation section '.rela.ifunc' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]*
> +
> +Relocation section '.rela.plt' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]*
> diff --git a/ld/testsuite/ld-ifunc/ifunc-18b.s b/ld/testsuite/ld-ifunc/ifunc-18b.s
> new file mode 100644
> index 0000000..fece413
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-18b.s
> @@ -0,0 +1,15 @@
> + .text
> + .type foo, %gnu_indirect_function
> + .hidden foo
> + .globl foo
> +foo:
> + ret
> + .size foo, .-foo
> + .globl bar
> +bar:
> + jmp foo1@PLT
> + ret
> + .size bar, .-bar
> + .hidden foo1
> + .globl foo1
> + foo1 = foo
> diff --git a/ld/testsuite/ld-ifunc/ifunc-19a-i386.d b/ld/testsuite/ld-ifunc/ifunc-19a-i386.d
> new file mode 100644
> index 0000000..8319bfc
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-19a-i386.d
> @@ -0,0 +1,14 @@
> +#source: ifunc-19a.s
> +#source: ifunc-19b.s
> +#ld: -shared -m elf_i386 -z nocombreloc
> +#as: --32
> +#readelf: -r --wide
> +#target: x86_64-*-* i?86-*-*
> +
> +Relocation section '.rel.ifunc' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]*
> +
> +Relocation section '.rel.plt' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]*
> diff --git a/ld/testsuite/ld-ifunc/ifunc-19a-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-19a-x86-64.d
> new file mode 100644
> index 0000000..fe576d2
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-19a-x86-64.d
> @@ -0,0 +1,14 @@
> +#source: ifunc-19a.s
> +#source: ifunc-19b.s
> +#as: --64
> +#ld: -shared -melf_x86_64 -z nocombreloc
> +#readelf: -r --wide
> +#target: x86_64-*-*
> +
> +Relocation section '.rela.ifunc' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]*
> +
> +Relocation section '.rela.plt' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]*
> diff --git a/ld/testsuite/ld-ifunc/ifunc-19a.s b/ld/testsuite/ld-ifunc/ifunc-19a.s
> new file mode 100644
> index 0000000..3a3d0cd
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-19a.s
> @@ -0,0 +1,5 @@
> + .section .data.rel,"aw",@progbits
> + .globl foo_ptrt
> + .type foo_ptr, @object
> +foo_ptr:
> + .dc.a foo1
> diff --git a/ld/testsuite/ld-ifunc/ifunc-19b-i386.d b/ld/testsuite/ld-ifunc/ifunc-19b-i386.d
> new file mode 100644
> index 0000000..5bb8170
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-19b-i386.d
> @@ -0,0 +1,14 @@
> +#source: ifunc-19b.s
> +#source: ifunc-19a.s
> +#ld: -shared -m elf_i386 -z nocombreloc
> +#as: --32
> +#readelf: -r --wide
> +#target: x86_64-*-* i?86-*-*
> +
> +Relocation section '.rel.ifunc' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]*
> +
> +Relocation section '.rel.plt' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]*
> diff --git a/ld/testsuite/ld-ifunc/ifunc-19b-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-19b-x86-64.d
> new file mode 100644
> index 0000000..35fa328
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-19b-x86-64.d
> @@ -0,0 +1,14 @@
> +#source: ifunc-19b.s
> +#source: ifunc-19a.s
> +#as: --64
> +#ld: -shared -melf_x86_64 -z nocombreloc
> +#readelf: -r --wide
> +#target: x86_64-*-*
> +
> +Relocation section '.rela.ifunc' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]*
> +
> +Relocation section '.rela.plt' at .*
> +[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
> +[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]*
> diff --git a/ld/testsuite/ld-ifunc/ifunc-19b.s b/ld/testsuite/ld-ifunc/ifunc-19b.s
> new file mode 100644
> index 0000000..fece413
> --- /dev/null
> +++ b/ld/testsuite/ld-ifunc/ifunc-19b.s
> @@ -0,0 +1,15 @@
> + .text
> + .type foo, %gnu_indirect_function
> + .hidden foo
> + .globl foo
> +foo:
> + ret
> + .size foo, .-foo
> + .globl bar
> +bar:
> + jmp foo1@PLT
> + ret
> + .size bar, .-bar
> + .hidden foo1
> + .globl foo1
> + foo1 = foo
I also checked this into 2.23 branch.
--
H.J.