binutils-gdb/ld
Maciej W. Rozycki 8507b6e797 MIPS16/GAS: Relax 32-bit non-PIC PC-relative synthetic instructions
Implement the relaxation of MIPS16 PC-relative synthetic LA, DLA, LW and
LD instructions to an equivalent sequence of instructions produced where
the address operand requested is out of range, absolute or requires
linker relocation, for ABIs that use 32-bit addressing and non-PIC code.

The sequence generated uses the register specified for the destination
operand as a temporary and begins with LI to load the high 16-bit part
of the address, then continues with SLL by 16 bits to move that part
into place and finally completes with a suitable operation corresponding
to the synthetic instruction used, one of: 2-argument ADDIU, 2-argument
DADDIU, absolute LW, and absolute LD respectively, providing the low
16-bit part of the address.  All instructions use the extended encoding.
As a special exception accept absolute addresses for relaxation even in
PIC code.

For example:

	la	$2, 0x12345678

produces code as:

	li	$2, 0x1234
	sll	$2, $2, 16
	addiu	$2, 0x5678

would.

Where linker relocation is required emit an R_MIPS16_HI16 relocation on
the initial LI instruction and an R_MIPS16_LO16 relocation on the final
operation.

For example (where `foo' is not local):

	lw	$3, foo

produces code as:

	li	$3, %hi(foo)
	sll	$3, $3, 16
	lw	$3, %lo(foo)($3)

would.

Emit assembly warnings as appropriate where this new relaxation triggers
in the `nomacro' mode or for an instruction manually placed in a branch
delay slot in the `noreorder' mode.  Refrain from relaxation where an
explicit instruction size suffix has been used and in the `noautoextend'
mode.

	gas/
	* config/tc-mips.c (RELAX_MIPS16_ENCODE): Add `pic', `sym32' and
	`nomacro' flags.
	(RELAX_MIPS16_PIC, RELAX_MIPS16_SYM32, RELAX_MIPS16_NOMACRO):
	New macros.
	(RELAX_MIPS16_USER_SMALL, RELAX_MIPS16_USER_EXT)
	(RELAX_MIPS16_DSLOT, RELAX_MIPS16_JAL_DSLOT)
	(RELAX_MIPS16_EXTENDED, RELAX_MIPS16_MARK_EXTENDED)
	(RELAX_MIPS16_CLEAR_EXTENDED, RELAX_MIPS16_ALWAYS_EXTENDED)
	(RELAX_MIPS16_MARK_ALWAYS_EXTENDED)
	(RELAX_MIPS16_CLEAR_ALWAYS_EXTENDED): Shift bits.
	(RELAX_MIPS16_MACRO, RELAX_MIPS16_MARK_MACRO)
	(RELAX_MIPS16_CLEAR_MACRO): New macros.
	(append_insn): Pass `mips_pic', HAVE_32BIT_SYMBOLS and
	`mips_opts.warn_about_macros' settings to RELAX_MIPS16_ENCODE.
	(mips16_macro_frag): New function.
	(md_estimate_size_before_relax): Handle HI16/LO16 relaxation.
	(mips_relax_frag): Likewise.
	(md_convert_frag): Likewise.

	* testsuite/gas/mips/mips16@relax-swap3.d: Remove error output,
	add dump patterns.
	* testsuite/gas/mips/mips16e@relax-swap3.d: New test
	subarchitecture.
	* testsuite/gas/mips/micromips@relax-swap3.d: Remove trailing
	NOP padding.
	* testsuite/gas/mips/mips16-pcrel-reloc-2.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-pcrel-reloc-3.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-pcrel-reloc-6.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-pcrel-reloc-7.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-pcrel-addend-2.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-pcrel-addend-3.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-pcrel-absolute.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-pcrel-absolute-1.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16@relax-swap3.l: Remove file.
	* testsuite/gas/mips/mips16-pcrel-reloc-2.l: Remove file.
	* testsuite/gas/mips/mips16-pcrel-reloc-3.l: Remove file.
	* testsuite/gas/mips/mips16-pcrel-reloc-6.l: Remove file.
	* testsuite/gas/mips/mips16-pcrel-reloc-7.l: Remove file.
	* testsuite/gas/mips/mips16-pcrel-addend-2.l: Remove file.
	* testsuite/gas/mips/mips16-pcrel-addend-3.l: Remove file.
	* testsuite/gas/mips/mips16-pcrel-absolute.l: Remove file.
	* testsuite/gas/mips/mips16-pcrel-absolute-1.l: Remove file.
	* testsuite/gas/mips/relax-swap3.s: Adjust trailing padding.

	* testsuite/gas/mips/mips16-pcrel-0.d: New test.
	* testsuite/gas/mips/mips16-pcrel-1.d: New test.
	* testsuite/gas/mips/mips16-pcrel-2.d: New test.
	* testsuite/gas/mips/mips16-pcrel-3.d: New test.
	* testsuite/gas/mips/mips16-pcrel-4.d: New test.
	* testsuite/gas/mips/mips16-pcrel-5.d: New test.
	* testsuite/gas/mips/mips16-pcrel-pic-0.d: New test.
	* testsuite/gas/mips/mips16-pcrel-pic-1.d: New test.
	* testsuite/gas/mips/mips16-pcrel-n32-0.d: New test.
	* testsuite/gas/mips/mips16-pcrel-n32-1.d: New test.
	* testsuite/gas/mips/mips16-pcrel-n64-sym32-0.d: New test.
	* testsuite/gas/mips/mips16-pcrel-n64-sym32-1.d: New test.
	* testsuite/gas/mips/mips16-pcrel-n64-0.d: New test.
	* testsuite/gas/mips/mips16-pcrel-n64-1.d: New test.
	* testsuite/gas/mips/mips16-pcrel-delay-0.d: New test.
	* testsuite/gas/mips/mips16-pcrel-delay-1.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-4.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-5.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-6.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-7.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-8.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-9.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-pic-8.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-pic-9.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-n32-8.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-n32-9.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-n64-sym32-8.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-n64-sym32-9.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-n64-8.d: New test.
	* testsuite/gas/mips/mips16-pcrel-addend-n64-9.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-2.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-3.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-4.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-5.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-6.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-7.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-pic-4.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-pic-6.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-n32-4.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-n32-6.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-n64-4.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-n64-6.d: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-n64-sym32-4.d: New
	test.
	* testsuite/gas/mips/mips16-pcrel-absolute-n64-sym32-6.d: New
	test.
	* testsuite/gas/mips/mips16-pcrel-absolute-pic-n32-4.d: New
	test.
	* testsuite/gas/mips/mips16-pcrel-absolute-pic-n32-6.d: New
	test.
	* testsuite/gas/mips/mips16-pcrel-absolute-pic-n64-4.d: New
	test.
	* testsuite/gas/mips/mips16-pcrel-absolute-pic-n64-6.d: New
	test.
	* testsuite/gas/mips/mips16-pcrel-absolute-pic-n64-sym32-4.d:
	New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-pic-n64-sym32-6.d:
	New test.
	* testsuite/gas/mips/mips16-pcrel-0.l: New stderr output.
	* testsuite/gas/mips/mips16-pcrel-1.l: New stderr output.
	* testsuite/gas/mips/mips16-pcrel-2.l: New stderr output.
	* testsuite/gas/mips/mips16-pcrel-3.l: New stderr output.
	* testsuite/gas/mips/mips16-pcrel-4.l: New stderr output.
	* testsuite/gas/mips/mips16-pcrel-5.l: New stderr output.
	* testsuite/gas/mips/mips16-pcrel-delay-0.l: New stderr output.
	* testsuite/gas/mips/mips16-pcrel-delay-1.l: New stderr output.
	* testsuite/gas/mips/mips16-pcrel-addend-8.l: New stderr output.
	* testsuite/gas/mips/mips16-pcrel-addend-9.l: New stderr output.
	* testsuite/gas/mips/mips16-pcrel-absolute-4.l: New stderr
	output.
	* testsuite/gas/mips/mips16-pcrel-absolute-6.l: New stderr
	output.
	* testsuite/gas/mips/mips16-pcrel-0.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-1.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-2.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-3.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-4.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-5.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-delay-0.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-delay-1.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-addend-4.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-addend-5.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-addend-6.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-addend-7.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-addend-8.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-addend-9.s: New test source.
	* testsuite/gas/mips/mips16-pcrel-absolute-2.s: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-3.s: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-4.s: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-5.s: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-6.s: New test.
	* testsuite/gas/mips/mips16-pcrel-absolute-7.s: New test.
	* testsuite/gas/mips/mips.exp: Run the new tests.

	ld/
	* testsuite/ld-mips-elf/mips16-pcrel-0.d: New test.
	* testsuite/ld-mips-elf/mips16-pcrel-1.d: New test.
	* testsuite/ld-mips-elf/mips16-pcrel-addend-2.d: New test.
	* testsuite/ld-mips-elf/mips16-pcrel-addend-6.d: New test.
	* testsuite/ld-mips-elf/mips16-pcrel-n32-0.d: New test.
	* testsuite/ld-mips-elf/mips16-pcrel-n32-1.d: New test.
	* testsuite/ld-mips-elf/mips16-pcrel-n64-sym32-0.d: New test.
	* testsuite/ld-mips-elf/mips16-pcrel-n64-sym32-1.d: New test.
	* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
2017-05-03 20:47:40 +01:00
..
emulparams Implement -z dynamic-undefined-weak 2017-04-19 20:39:52 +09:30
emultempl PR 21274, ld segfaults linking PE DLL 2017-04-11 19:49:13 +09:30
po Add Serbian translation for the LD directory. 2017-01-27 11:27:50 +00:00
scripttempl Place read-only data in the text section on AVR Tiny targets. 2017-02-27 17:05:53 +00:00
testsuite MIPS16/GAS: Relax 32-bit non-PIC PC-relative synthetic instructions 2017-05-03 20:47:40 +01:00
.gitignore
aclocal.m4 Regenerate Makefile.in/aclocal.m4 automake 1.11.6 2016-04-15 16:20:55 -07:00
ChangeLog MIPS16/GAS: Relax 32-bit non-PIC PC-relative synthetic instructions 2017-05-03 20:47:40 +01:00
ChangeLog-0001 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-0203 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-2004 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-2005 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-2006 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-2007 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-2008 strip off +x bits on non-executable/script files 2013-12-07 02:03:03 -05:00
ChangeLog-2009 Remove trailing spaces in ld 2015-08-12 04:46:43 -07:00
ChangeLog-2010 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-2011 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-2012 Rotate binutils ChangeLog for 2013 2013-01-02 17:06:32 +00:00
ChangeLog-2013 New Year - binutils ChangeLog rotation 2014-01-08 05:32:12 -08:00
ChangeLog-2014 ChangeLog rotatation and copyright year update 2015-01-02 00:53:45 +10:30
ChangeLog-2015 binutils ChangeLog rotation 2016-01-01 22:59:17 +10:30
ChangeLog-2016 ChangeLog rotation 2017-01-02 13:55:05 +10:30
ChangeLog-9197 Remove trailing spaces in ld 2015-08-12 04:46:43 -07:00
ChangeLog-9899 Add copyright notices 2012-12-10 12:48:03 +00:00
config.in Remove support for $PLATFORM in rpath search paths. 2016-11-04 13:57:40 +00:00
configure Add Serbian translation for the LD directory. 2017-01-27 11:27:50 +00:00
configure.ac Add Serbian translation for the LD directory. 2017-01-27 11:27:50 +00:00
configure.host Run more ld tests when not native 2017-01-02 23:48:08 +10:30
configure.tgt IA16 support 2017-04-03 09:13:19 -07:00
deffile.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
deffilep.y Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
dep-in.sed
elf-hints-local.h Remove trailing white spaces in ld 2013-01-10 20:08:03 +00:00
fdl.texi
gen-doc.texi Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
genscrba.sh
genscripts.sh Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
h8-doc.texi Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ld.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ld.texinfo Implement -z dynamic-undefined-weak 2017-04-19 20:39:52 +09:30
ldbuildid.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldbuildid.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldcref.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldctor.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldctor.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldemul.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldemul.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldexp.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldexp.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldfile.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldfile.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldgram.y Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldint.texinfo Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldlang.c PR ld/21233: Avoid sweeping forced-undefined symbols in section GC 2017-04-04 23:21:44 +01:00
ldlang.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldlex-wrapper.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldlex.h Use noyywrap option in lex files. 2017-01-04 16:05:22 +00:00
ldlex.l Use noyywrap option in lex files. 2017-01-04 16:05:22 +00:00
ldmain.c Fix buffer overflows in ld when printing translated strings. 2017-01-31 12:07:04 +00:00
ldmain.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldmisc.c LD: vfinfo: Make clever formatters consistent WRT function name reporting 2017-02-15 13:41:51 +00:00
ldmisc.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldver.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldver.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldwrite.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
ldwrite.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
lexsup.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
MAINTAINERS Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
Makefile.am Implement -z dynamic-undefined-weak 2017-04-19 20:39:52 +09:30
Makefile.in Implement -z dynamic-undefined-weak 2017-04-19 20:39:52 +09:30
mri.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
mri.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
NEWS Support ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX 2017-04-04 09:06:04 -07:00
pe-dll.c PR 21274, ld segfaults linking PE DLL 2017-04-11 19:49:13 +09:30
pe-dll.h PR 21274, ld segfaults linking PE DLL 2017-04-11 19:49:13 +09:30
pep-dll.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
pep-dll.h PR 21274, ld segfaults linking PE DLL 2017-04-11 19:49:13 +09:30
plugin.c Handle symbol defined in IR and referenced in DSO 2017-04-20 07:48:35 -07:00
plugin.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
README Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
stamp-h.in
sysdep.h Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
testplug2.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
testplug3.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
testplug4.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
testplug.c Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
TODO

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

		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.