I noticed recently that .eh_frame FDEs generated by the linker for
call stubs and .glink weren't being indexed in .eh_frame_hdr, due to
bfd_elf_discard_info being run before the linker generated .eh_frame
sections were available for parsing. This patch moves code around in
elf64-ppc.c and ppc64elf.em to avoid that problem.
Another problem fixed here is that --gc-sections parses .eh_frame
early, and the existing machinery allows only one go at parsing the
.eh_frame sections. That resulted in the linker generated .eh_frame
CIEs not being merged and no .eh_frame_hdr index entries for those
FDEs. It turns out that all the info from parsing .eh_frame is
attached to the section, so order of parsing isn't important, and
after parsing sec_info_type being set will prevent a section being
parsed again. At least, when parsing doesn't hit an error. So there
isn't really any need for "parsed_eh_frame". "merge_cies" is also
redundant, which means _bfd_elf_{begin,end}_eh_frame_parsing can also
disappear.
bfd/
* elf-bfd.h (struct eh_frame_hdr_info): Delete merge_cies and
parsed_eh_frames.
(_bfd_elf_begin_eh_frame_parsing): Delete.
(_bfd_elf_end_eh_frame_parsing): Delete.
* elf-eh-frame.c (_bfd_elf_begin_eh_frame_parsing): Delete.
(_bfd_elf_end_eh_frame_parsing): Delete.
(_bfd_elf_parse_eh_frame): Don't test parsed_eh_frame. Test
!info->relocatable in place of merge_cies.
* elflink.c (bfd_elf_gc_sections, bfd_elf_discard_info): Adjust.
* elf64-ppc.c (glink_eh_frame_cie): Pad to multiple of 8.
(ppc64_elf_size_stubs): Likewise pad stub FDE.
(ppc64_elf_build_stubs): Move code setting glink .eh_frame to..
(ppc64_elf_size_stubs): ..here and..
(ppc64_elf_finish_dynamic_sections): ..here.
ld/
* emultempl/ppc64elf.em (gld${EMULATION_NAME}_after_allocation): Call
bfd_elf_discard_info after generating glink .eh_frame. Delete
redundant test on ppc64_elf_setup_section_lists status.
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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) 2012-2014 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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