[bfd] Provide 8-byte minimum alignment for .plt section
This change increases the default alignment for the .plt section
from 4 bytes to 8 bytes. When function descriptors are 8-byte
aligned, they can be updated atomically on 32-bit hppa. This
helps with ordering issues on SMP machines. It also ensures
that descriptors reside on the same cache line. This reduces
the probability of a double TLB miss in a call.
2019-10-20 John David Anglin <danglin@gcc.gnu.org>
* elf32-hppa.c (elf32_hppa_size_dynamic_sections): Provide 8-byte
minimum alignment for .plt section.
This commit updates the import stubs to leave the pointer to the
function descriptor in register %r22. This provides a backup
mechanism for _dl_runtime_resolve to fixup descriptors during
lazy binding.
bfd/ChangeLog
2019-10-20 John David Anglin <danglin@gcc.gnu.org>
* elf32-hppa.c: Revise import stub sequences.
(LONG_BRANCH_STUB_SIZE): Define.
(LONG_BRANCH_SHARED_STUB_SIZE): Define.
(IMPORT_STUB_SIZE): Define.
(IMPORT_SHARED_STUB_SIZE): Define.
(EXPORT_STUB_SIZE): Define.
(plt_stub): Revise to not use register %r22.
(LDO_R1_R22): Define.
(LDW_R22_R21): Define.
(LDW_R22_R19): Define.
(hppa_build_one_stub): Update stub generation and use new defines.
(hppa_size_one_stub): Likewise.
Tamar Christina [Tue, 24 Sep 2019 13:46:17 +0000 (14:46 +0100)]
Arm: Fix out of range conditional branch (PR/24991)
The fix for PR12848 introduced an off by one error in the mask, this corrected
the negative overflows but not the positive overflows. As a result the
conditional branch instructions accepted a too wide positive immediate which
resulted in it corrupting the instruction during encoding.
The relocation I believe has been incorrectly named, to be consistent with the
other relocations it should have been named BRANCH21 which is why the masks for
it are confusing.
I've replaced the masks with a function out_of_range_p which should make it
harder to make such mistakes.
The mask for BL/BLX on Armv6t+ is also wrong, the extended range is 25-bits
and so the mask should be checking for 24-bits for positive overflow.
gas/ChangeLog:
PR gas/24991
* config/tc-arm.c (out_of_range_p): New.
(md_apply_fix): Use it in BFD_RELOC_THUMB_PCREL_BRANCH9,
BFD_RELOC_THUMB_PCREL_BRANCH12, BFD_RELOC_THUMB_PCREL_BRANCH20,
BFD_RELOC_THUMB_PCREL_BRANCH23, BFD_RELOC_THUMB_PCREL_BRANCH25
* testsuite/gas/arm/pr24991.d: New test.
* testsuite/gas/arm/pr24991.l: New test.
* testsuite/gas/arm/pr24991.s: New test.
Alan Modra [Wed, 9 Oct 2019 10:55:25 +0000 (21:25 +1030)]
PR25081, Discrepancy between VMA and LMA after ALIGN
The testcase in the PR has two empty output sections, .sec1 with an
ALIGN and symbol assignment, and .sec2 just with an empty input
section. The symbol assignment results in .sec1 being kept, but
because it is empty this section doesn't take space from the memory
region as you might expect from the ALIGN. Instead the next section
.sec2, has vma/lma as if .sec1 wasn't present. However, .sec2 is
discarded and os->ignored set, which unfortunately meant that dot
wasn't set from .sec2 vma. That in turn results in .sec2 lma being
set incorrectly. That vma/lma difference is then propagated to
.sec3 where it is seen as an overlap.
PR 25081
* ldlang.c (lang_size_sections_1): Set lma from section vma
rather than dot.
Szabolcs Nagy [Wed, 2 Oct 2019 18:46:46 +0000 (19:46 +0100)]
[PR ld/22263][PR ld/25056] arm: Avoid dynamic TLS relocs in PIE
Dynamic relocs are only needed in an executable for TLS symbols if
those are defined in an external module and even then TLS access
can be relaxed to use IE model instead of GD.
Several bfd_link_pic checks are turned into bfd_link_dll checks
to fix TLS handling in PIE, for the same fix some other targets
used !bfd_link_executable checks, but that includes relocatable
objects so dll seems safer (in most cases either should work, since
dynamic relocations are not applied in relocatable objects).
On arm* fixes
FAIL: Build pr22263-1
bfd/
PR ld/22263
PR ld/25056
* elf32-arm.c (elf32_arm_tls_transition): Use bfd_link_dll instead of
bfd_link_pic for TLS checks.
(elf32_arm_final_link_relocate): Likewise.
(allocate_dynrelocs_for_symbol): Likewise.
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