Use frag symbols with a non-zero offset directly in `fix_new_exp' calls
made in PIC branch relaxation. There is no need here to make a helper
symbol to hold the result of a `symbol+offset' calculation requested as
only branches to local symbols are relaxed and in this case the LO16
part of the PIC address load sequence will have the offset accounted for
in calculation against the local GOT entry retrieved as the GOT16 high
part. Consequently actual code produed is identical whether a helper
symbol is used or the original `symbol+offset' expression used directly.
Verify that this is indeed the case with GAS and LD tests.
gas/
* config/tc-mips.c (md_convert_frag): Don't make a helper
expression symbol for `fix_new_exp' called with a non-zero
offset.
* testsuite/gas/mips/relax-offset.d: New test.
* testsuite/gas/mips/mips1@relax-offset.d: New test.
* testsuite/gas/mips/r3000@relax-offset.d: New test.
* testsuite/gas/mips/r3900@relax-offset.d: New test.
* testsuite/gas/mips/micromips@relax-offset.d: New test.
* testsuite/gas/mips/relax-offset.l: New stderr output.
* testsuite/gas/mips/relax-offset.s: New test source.
* testsuite/gas/mips/mips.exp: Run the new tests.
ld/
* testsuite/ld-mips-elf/relax-offset.dd: New test.
* testsuite/ld-mips-elf/relax-offset.gd: New test.
* testsuite/ld-mips-elf/relax-offset-umips.dd: New test.
* testsuite/ld-mips-elf/relax-offset-umips.gd: New test.
* testsuite/ld-mips-elf/relax-offset.ld: New test linker script.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
(prune_warnings): New temporary procedure.
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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) 2012-2017 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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