This patch adds --compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}
options to gas and objcopy for ELF files. They control how DWARF debug
sections are compressed. --compress-debug-sections=none is equivalent to
--nocompress-debug-sections. --compress-debug-sections=zlib and
--compress-debug-sections=zlib-gnu are equivalent to
--compress-debug-sections. --compress-debug-sections=zlib-gabi compresses
DWARF debug sections with SHF_COMPRESSED from the ELF ABI. No linker
changes are required to support SHF_COMPRESSED.
bfd/
* archive.c (_bfd_get_elt_at_filepos): Also copy BFD_COMPRESS_GABI
bit.
* bfd.c (bfd::flags): Increase size to 18 bits.
(BFD_COMPRESS_GABI): New.
(BFD_FLAGS_SAVED): Add BFD_COMPRESS_GABI.
(BFD_FLAGS_FOR_BFD_USE_MASK): Likewise.
(bfd_update_compression_header): New fuction.
(bfd_check_compression_header): Likewise.
(bfd_get_compression_header_size): Likewise.
(bfd_is_section_compressed_with_header): Likewise.
* compress.c (MAX_COMPRESSION_HEADER_SIZE): New.
(bfd_compress_section_contents): Return the uncompressed size if
the full section contents is compressed successfully. Support
converting from/to .zdebug* sections.
(bfd_get_full_section_contents): Call
bfd_get_compression_header_size to get compression header size.
(bfd_is_section_compressed): Renamed to ...
(bfd_is_section_compressed_with_header): This. Add a pointer
argument to return compression header size.
(bfd_is_section_compressed): Use it.
(bfd_init_section_decompress_status): Call
bfd_get_compression_header_size to get compression header size.
Return FALSE if uncompressed section size is 0.
* elf.c (_bfd_elf_make_section_from_shdr): Support converting
from/to .zdebug* sections.
* bfd-in2.h: Regenerated.
binutils/
* objcopy.c (do_debug_sections): Add compress_zlib,
compress_gnu_zlib and compress_gabi_zlib.
(copy_options): Use optional_argument on compress-debug-sections.
(copy_usage): Update --compress-debug-sections.
(copy_file): Handle compress_zlib, compress_gnu_zlib and
compress_gabi_zlib.
(copy_main): Handle
--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.
* doc/binutils.texi: Document
--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.
binutils/testsuite/
* compress.exp: Add tests for
--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.
* binutils-all/dw2-3.rS: New file.
* binutils-all/dw2-3.rt: Likewise.
* binutils-all/libdw2-compressedgabi.out: Likewise.
gas/
* as.c (show_usage): Update --compress-debug-sections.
(std_longopts): Use optional_argument on compress-debug-sections.
(parse_args): Handle
--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.
* as.h (compressed_debug_section_type): New.
(flag_compress_debug): Change type to compressed_debug_section_type.
--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.
* write.c (compress_debug): Set BFD_COMPRESS_GABI for
--compress-debug-sections=zlib-gabi. Call
bfd_get_compression_header_size to get compression header size.
Don't rename section name for --compress-debug-sections=zlib-gabi.
* config/tc-i386.c (compressed_debug_section_type): Set to
COMPRESS_DEBUG_ZLIB.
* doc/as.texinfo: Document
--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.
gas/testsuite/
* gas/i386/dw2-compressed-1.d: New file.
* gas/i386/dw2-compressed-2.d: Likewise.
* gas/i386/dw2-compressed-3.d: Likewise.
* gas/i386/x86-64-dw2-compressed-2.d: Likewise.
* gas/i386/i386.exp: Run dw2-compressed-2, dw2-compressed-1,
dw2-compressed-3 and x86-64-dw2-compressed-2.
ld/testsuite/
* ld-elf/compress.exp: Add a test for
--compress-debug-sections=zlib-gabi.
(build_tests): Add 2 tests for --compress-debug-sections=zlib-gabi.
(run_tests): Likewise.
Verify linker output with zlib-gabi compressed debug input.
* ld-elf/compressed1a.d: New file.
* ld-elf/compressed1b.d: Likewise.
* ld-elf/compressed1c.d: Likewise.
Fixes tic6x testsuite failures due to .rela.plt having a zero sh_info.
I considered passing link_info to get_reloc_section so we could
directly return the .got.plt output section, but we need the fallback
to name lookup anyway for objcopy.
bfd/
* elf.c (_bfd_elf_get_reloc_section): Allow for .got.plt being
mapped to output .got section.
ld/testsuite/
* ld-arm/tls-gdesc-nlazy.g: Adjust for readelf note.
* ld-tic6x/shlib-1.rd: Expect corrected .rela.plt sh_info.
* ld-tic6x/shlib-1b.rd: Likewise.
* ld-tic6x/shlib-1r.rd: Likewise.
* ld-tic6x/shlib-1rb.rd: Likewise.
* ld-tic6x/shlib-app-1.rd: Likewise.
* ld-tic6x/shlib-app-1b.rd: Likewise.
* ld-tic6x/shlib-app-1r.rd: Likewise.
* ld-tic6x/shlib-app-1rb.rd: Likewise.
* ld-tic6x/shlib-noindex.rd: Likewise.
This is a linker-only solution to the incompatibility between shared
library protected visibility variables and using .dynbss and copy
relocs for non-PIC access to shared library variables.
bfd/
* elf32-ppc.c (struct ppc_elf_link_hash_entry): Add has_addr16_ha
and has_addr16_lo. Make has_sda_refs a bitfield.
(ppc_elf_check_relocs): Set new flags.
(ppc_elf_link_hash_table_create): Update default_params.
(ppc_elf_adjust_dynamic_symbol): Clear protected_def in cases
where we won't be making .dynbss entries or editing code. Set
params->pic_fixup when we'll edit code for protected var access.
(allocate_dynrelocs): Allocate got entry for edited code and
discard dyn_relocs.
(struct ppc_elf_relax_info): Add picfixup_size.
(ppc_elf_relax_section): Rename struct one_fixup to struct
one_branch_fixup. Rename fixups to branch_fixups. Size space for
pic fixups.
(ppc_elf_relocate_section): Edit non-PIC accessing protected
visibility variables to PIC. Don't emit dyn_relocs for code
we've edited.
* elf32-ppc.h (struct ppc_elf_params): Add pic_fixup.
ld/
* emultempl/ppc32elf.em: Handle --no-pic-fixup.
(params): Init new field.
(ppc_before_allocation): Enable relaxation for pic_fixup.
For objcopy and relocatable link, we should also preserve the
SHF_COMPRESSED bit if not decompress.
* elf.c (_bfd_elf_init_private_section_data): Also preserve the
SHF_COMPRESSED bit if not decompress.
Some early revisions of the Cortex-A53 have an erratum (843419). The
details of the erratum are quite complex and involve dynamic
conditions. For the purposes of the workaround we have simplified the
static conditions to an ADRP in the last two instructions of a 4KByte
page, followed within four instructions by a load/store dependent on
the ADRP.
This patch adds support to conservatively scan for and workaround
Cortex A53 erratum 843419. There are two different workaround
strategies used. The first is to rewrite ADRP instructions which form
part of an erratum sequence with an ADR instruction. In situations
where the ADR provides insufficient offset the dependent load or store
instruction from the sequence is moved to a stub section and branches
are inserted from the original sequence to the relocated instruction
and back again.
Stub section sizes are rounded up to a multiple of 4096 in order to
ensure that the act of inserting work around stubs does not create
more errata sequences.
Workaround stubs are always inserted into the stub section associated
with the input section containing the erratum sequence. This ensures
that the fully relocated form of the veneered load store instruction
is available at the point in time when the stub section is written.
Since .rela.plt/rel.plt section may contain relocations against .got.plt
section, we set sh_info for .rela.plt/rel.plt section to .got.plt section
index if target has .got.plt section.
bfd/
PR ld/18169
* elf-bfd.h (elf_backend_data): Add get_reloc_section.
(_bfd_elf_get_reloc_section): New.
* elf.c (_bfd_elf_get_reloc_section): Likewise.
(assign_section_numbers): Call get_reloc_section to look up the
section the relocs apply.
* elfxx-target.h (elf_backend_get_reloc_section): Likewise.
(elfNN_bed): Initialize get_reloc_section with
elf_backend_get_reloc_section.
ld/testsuite/
PR ld/18169
* ld-elf/linkinfo1a.d: Updated.
* ld-elf/linkinfo1b.d: Likewise.
Allows .dynbss copy of shared library protected visibility variables
if they are read-only.
To recap: Copying a variable from a shared library into an executable's
.dynbss is an old hack invented for non-PIC executables, to avoid the
text relocations you'd otherwise need to access a shared library
variable. This works with ELF shared libraries because global
symbols can be overridden. The trouble is that protected visibility
symbols can't be overridden. A shared library will continue to access
it's own protected visibility variable while the executable accesses a
copy. If either the shared library or the executable updates the
value then the copy diverges from the original. This is wrong since
there is only one definition of the variable in the application.
So I made the linker report an error on attempting to copy protected
visibility variables into .dynbss. However, you'll notice the above
paragraph contains an "If". An application that does not modify the
variable value remains correct even though two copies of the variable
exist. The linker can detect this situation if the variable was
defined in a read-only section.
PR ld/15228
PR ld/18167
* elflink.c (elf_merge_st_other): Add "sec" parameter. Don't set
protected_def when symbol section is read-only. Adjust all calls.
* elf-bfd.h (struct elf_link_hash_entry): Update protected_def comment.
Ensure that injection of a stub section does not break a link where
there is an xpectation that flow of control can pass from one input
section to another simply by linking the input sections in series.
The solution here is to allow stub sections to be inserted after any
input section (existing behaviour), but inject an additional branch at
the start of each stub section such that control flow falling into the
stub section will branch over the stub section.
I noticed that _bfd_elf_gc_mark_extra_sections attempts to unmark
related debug sections when it finds an unmarked code section.
When it finds .text.foo is unmarked, for example, it removes
.debug_line.text.foo as well (using the section name as a suffix
match check.
However, it bails out after finding one such section.
bfd/
* elflink.c (_bfd_elf_gc_mark_extra_sections): Don't break on
first matching debug section.
ld/testsuite/
* ld-gc/all-debug-sections.d: New file.
* ld-gc/all-debug-sections.s: Likewise.
* ld-gc/gc.exp: Execute new testcase.
No need to write the zlib header if compression didn't make the section
smaller.
PR binutils/18087
* compress.c (bfd_compress_section_contents): Don't write the
zlib header and set contents as well as compress_status if
compression didn't make the section smaller.
(bfd_init_section_compress_status): Don't check compression
size here.
Change the behaviour of section_group[] such that .stub_sec points to
the stub section attached to the indexed section rather than the stub
section attached to the link_section pointed to be the index section.
This provides a mechanism to get to the stub section following any
input section. While still allowing the section grouping mechanism to
find the section group stub section associated with an input section
by first following the link_sec pointer.
This patch recognizes that we only need to perform one scan for the
835769 errata and that this scan can take place before we insert
branch stubs. The erratum scan code is relocated and adjusted to
create stub entries directly rather than populating an intermediate
representation. Since stub entries are created immediately we can
drop the adhoc stub size adjustment code and allow the generic stub
sizing code to deal with 835769 stub entries.
This patch restructures the code but does not change the workaround
used to deal with erratum 83679, the exact placement of workaround
stubs in the final image may change slightly after this patch due to
stubs being created in a different order.
* elf64-ppc.c (ppc64_elf_relocate_section): Report overflow to
stubs, even those for undefined weak symbols. Otherwise, don't
report relocation overflow on branches to undefined strong
symbols. Fix memory leak.
* elf32-ppc.c (ppc_elf_relocate_section): Don't report relocation
overflow on branches to undefined strong symbols.
GDB Administrator
H.J. Lu
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