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.
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README for LD
This is the GNU linker. It is distributed with other "binary
utilities" which should be in ../binutils. See ../binutils/README for
more general notes, including where to send bug reports.
There are many features of the linker:
* The linker uses a Binary File Descriptor library (../bfd)
that it uses to read and write object files. This helps
insulate the linker itself from the format of object files.
* The linker supports a number of different object file
formats. It can even handle multiple formats at once:
Read two input formats and write a third.
* The linker can be configured for cross-linking.
* The linker supports a control language.
* There is a user manual (ld.texinfo), as well as the
beginnings of an internals manual (ldint.texinfo).
Installation
============
See ../binutils/README.
If you want to make a cross-linker, you may want to specify
a different search path of -lfoo libraries than the default.
You can do this by setting the LIB_PATH variable in ./Makefile
or using the --with-lib-path configure switch.
To build just the linker, make the target all-ld from the top level
directory (one directory above this one).
Porting to a new target
=======================
See the ldint.texinfo manual.
Reporting bugs etc
===========================
See ../binutils/README.
Known problems
==============
The Solaris linker normally exports all dynamic symbols from an
executable. The GNU linker does not do this by default. This is
because the GNU linker tries to present the same interface for all
similar targets (in this case, all native ELF targets). This does not
matter for normal programs, but it can make a difference for programs
which try to dlopen an executable, such as PERL or Tcl. You can make
the GNU linker export all dynamic symbols with the -E or
--export-dynamic command line option.
HP/UX 9.01 has a shell bug that causes the linker scripts to be
generated incorrectly. The symptom of this appears to be "fatal error
- scanner input buffer overflow" error messages. There are various
workarounds to this:
* Build and install bash, and build with "make SHELL=bash".
* Update to a version of HP/UX with a working shell (e.g., 9.05).
* Replace "(. ${srcdir}/scripttempl/${SCRIPT_NAME}.sc)" in
genscripts.sh with "sh ${srcdir}..." (no parens) and make sure the
emulparams script used exports any shell variables it sets.
Copyright (C) 2012-2015 Free Software Foundation, Inc.
Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.
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