diff options
| author | Alan Modra <amodra@gmail.com> | 2017-08-14 09:25:17 +0930 |
|---|---|---|
| committer | Alan Modra <amodra@gmail.com> | 2017-08-14 09:25:17 +0930 |
| commit | 79a94a2ad1e6e2f227de07427481e4bb8be84504 (patch) | |
| tree | 9cdf64ff2ae956d9ffd96d87bc1404eee27f933e /bfd | |
| parent | 34c4758cc210e2ca042b0373938e57fd6844f89d (diff) | |
| download | gdb-79a94a2ad1e6e2f227de07427481e4bb8be84504.zip gdb-79a94a2ad1e6e2f227de07427481e4bb8be84504.tar.gz gdb-79a94a2ad1e6e2f227de07427481e4bb8be84504.tar.bz2 | |
PR21441, Unnecessary padding of .eh_frame section
Until all .eh_frame sections have been edited we don't know their
sizes. So it isn't possible to properly decide whether a non-empty
.eh_frame section follows a given section until editing is complete.
bfd/
PR 21441
* elf-eh-frame.c (_bfd_elf_discard_section_eh_frame): Don't add
alignment padding here.
* elflink.c (bfd_elf_discard_info): Add .eh_frame padding here
in a reverse pass over sections.
ld/
PR 21441
* testsuite/ld-x86-64/pr21038a.d: Adjust.
* testsuite/ld-x86-64/pr21038a-now.d: Adjust.
Diffstat (limited to 'bfd')
| -rw-r--r-- | bfd/ChangeLog | 8 | ||||
| -rw-r--r-- | bfd/elf-eh-frame.c | 9 | ||||
| -rw-r--r-- | bfd/elflink.c | 29 |
3 files changed, 37 insertions, 9 deletions
diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 356d19b..876461e 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,11 @@ +2017-08-14 Alan Modra <amodra@gmail.com> + + PR 21441 + * elf-eh-frame.c (_bfd_elf_discard_section_eh_frame): Don't add + alignment padding here. + * elflink.c (bfd_elf_discard_info): Add .eh_frame padding here + in a reverse pass over sections. + 2017-08-11 H.J. Lu <hongjiu.lu@intel.com> PR binutils/21943 diff --git a/bfd/elf-eh-frame.c b/bfd/elf-eh-frame.c index 52ba9c6..7e0d63f 100644 --- a/bfd/elf-eh-frame.c +++ b/bfd/elf-eh-frame.c @@ -1594,16 +1594,7 @@ _bfd_elf_discard_section_eh_frame offset += size_of_output_cie_fde (ent); } - /* Pad the last FDE out to the output section alignment if there are - following sections, in order to ensure no padding between this - section and the next. (Relies on the output section alignment - being the maximum of all input sections alignments, which is the - case unless someone is overriding alignment via scripts.) */ eh_alignment = 4; - if (sec->map_head.s != NULL - && (sec->map_head.s->size != 4 - || sec->map_head.s->map_head.s != NULL)) - eh_alignment = 1 << sec->output_section->alignment_power; offset = (offset + eh_alignment - 1) & -eh_alignment; sec->rawsize = sec->size; sec->size = offset; diff --git a/bfd/elflink.c b/bfd/elflink.c index 424de21..f9886dc 100644 --- a/bfd/elflink.c +++ b/bfd/elflink.c @@ -13836,6 +13836,7 @@ bfd_elf_discard_info (bfd *output_bfd, struct bfd_link_info *info) { asection *i; int eh_changed = 0; + unsigned int eh_alignment; for (i = o->map_head.s; i != NULL; i = i->map_head.s) { @@ -13861,6 +13862,34 @@ bfd_elf_discard_info (bfd *output_bfd, struct bfd_link_info *info) fini_reloc_cookie_for_section (&cookie, i); } + eh_alignment = 1 << o->alignment_power; + if (eh_alignment > 4) + { + /* Skip over zero terminator, and prevent empty sections + from adding alignment padding at the end. */ + for (i = o->map_tail.s; i != NULL; i = i->map_tail.s) + if (i->size == 0) + i->flags |= SEC_EXCLUDE; + else if (i->size > 4) + break; + /* The last non-empty eh_frame section doesn't need padding. */ + if (i != NULL) + i = i->map_tail.s; + /* Any prior sections must pad the last FDE out to the + output section alignment. Otherwise we might have zero + padding between sections, which would be seen as a + terminator. */ + for (; i != NULL; i = i->map_tail.s) + { + bfd_size_type size = (i->size + eh_alignment - 1) & -eh_alignment; + if (i->size != size) + { + i->size = size; + changed = 1; + eh_changed = 1; + } + } + } if (eh_changed) elf_link_hash_traverse (elf_hash_table (info), _bfd_elf_adjust_eh_frame_global_symbol, NULL); |