binutils-gdb/gas
Matthew Fortune 99e7978bd2 MIPS16/GAS: Fix delay slot filling across frags
Fix an assertion failure like:

test.s: Assembler messages:
test.s:3: Internal error!
Assertion failure in append_insn at .../gas/config/tc-mips.c:7523.
Please report this bug.

triggered by assembling MIPS16 code like:

hello:
	addiu	$4, $4, 4
	jr	$31

with the generation of a listing file enabled, e.g.:

$ as -mips16 -O2 -aln=test.lst

The cause of the problem is the lack of support for moving instructions
across frags in MIPS16 jump swapping, which triggers more easily with
listing enabled as in that case every instruction gets placed in its own
frag.  It would trigger even with listing disabled though if the
instruction to swap a MIPS16 jump with was unfortunately enough placed
as last in a frag that became full.

This scenario is already handled correctly with branch swapping in
regular MIPS and microMIPS code, so reuse it for MIPS16 code as well,
and now that all MIPS16 handling has become the same as the regular MIPS
and microMIPS cases remove MIPS16 special casing altogether.

This effectively complements:

commit 464ab0e55a
Author: Maciej W. Rozycki <macro@linux-mips.org>
Date:   Mon Aug 6 20:33:00 2012 +0000

<https://sourceware.org/ml/binutils/2012-08/msg00043.html>, ("MIPS/GAS:
Correct microMIPS branch swapping assertion") for the MIPS16 case.

The assertion itself was introduced with:

commit 1e91584932
Author: Richard Sandiford <rdsandiford@googlemail.com>
Date:   Wed Mar 9 09:17:02 2005 +0000

<https://sourceware.org/ml/binutils/2005-03/msg00217.html>, ("Rework
MIPS nop-insertion code, add -mfix-vr4130 [5/11]"), but its introduction
merely noted our existing lack of support for MIPS16 jump swapping
across frags.

	gas/
	* config/tc-mips.c (append_insn) <APPEND_SWAP>: Do not special
	case MIPS16 handling.
	* testsuite/gas/mips/branch-swap-3.d: New test.
	* testsuite/gas/mips/branch-swap-4.d: New test.
	* testsuite/gas/mips/mips16@branch-swap-3.d: New test.
	* testsuite/gas/mips/mips16@branch-swap-4.d: New test.
	* testsuite/gas/mips/micromips@branch-swap-3.d: New test.
	* testsuite/gas/mips/micromips@branch-swap-4.d: New test.
	* testsuite/gas/mips/branch-swap-3.s: New test source.
	* testsuite/gas/mips/mips.exp: Run the new tests.
2016-06-30 15:11:23 +01:00
..
config MIPS16/GAS: Fix delay slot filling across frags 2016-06-30 15:11:23 +01:00
doc Add command line option to stop the assembler from padding the end of sections to their alignment boundary. 2016-06-27 13:51:06 +01:00
po Copyright update for binutils 2016-01-01 23:00:01 +10:30
testsuite MIPS16/GAS: Fix delay slot filling across frags 2016-06-30 15:11:23 +01:00
.gitignore bfd/binutils/gas/gprof/ld/libiberty/opcodes: add .gitignore 2010-12-09 09:03:18 +00:00
acinclude.m4 Update "configure.in" in comments and doco 2014-07-04 15:06:40 +09:30
aclocal.m4 Regenerate Makefile.in/aclocal.m4 automake 1.11.6 2016-04-15 16:20:55 -07:00
app.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
as.c Allow ARC target to be configured with --with-cpu=<cpu-name>. 2016-06-30 11:14:41 +01:00
as.h Add command line option to stop the assembler from padding the end of sections to their alignment boundary. 2016-06-27 13:51:06 +01:00
asintl.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
atof-generic.c Remove use of alloca. 2016-03-21 16:31:46 +00:00
bignum.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
bit_fix.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
cgen.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
cgen.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
ChangeLog MIPS16/GAS: Fix delay slot filling across frags 2016-06-30 15:11:23 +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 Remove trailing spaces in gas 2015-08-12 04:40:42 -07:00
ChangeLog-2006 Remove trailing spaces in gas 2015-08-12 04:40:42 -07:00
ChangeLog-2007 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-2008 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-2009 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-2010 Remove trailing spaces in gas 2015-08-12 04:40:42 -07:00
ChangeLog-2011 Add copyright notices 2012-12-10 12:48:03 +00:00
ChangeLog-2012 correct pr reference 2013-02-04 05:10:44 +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-9295 Remove trailing spaces in gas 2015-08-12 04:40:42 -07:00
ChangeLog-9697 Update copyright years 2014-03-05 22:16:15 +10:30
ChangeLog-9899 Update copyright years 2014-03-05 22:16:15 +10:30
compress-debug.c Copyright update for binutils 2016-01-01 23:00:01 +10:30
compress-debug.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
cond.c Add more const type qualifiers to GAS sources. 2016-02-22 14:11:27 +00:00
config.in Allow ARC target to be configured with --with-cpu=<cpu-name>. 2016-06-30 11:14:41 +01:00
configure Allow ARC target to be configured with --with-cpu=<cpu-name>. 2016-06-30 11:14:41 +01:00
configure.ac Allow ARC target to be configured with --with-cpu=<cpu-name>. 2016-06-30 11:14:41 +01:00
configure.com Copyright update for binutils 2016-01-01 23:00:01 +10:30
configure.tgt Default to --enable-compressed-debug-sections=gas for Linux/x86 2016-06-29 09:32:34 -07:00
CONTRIBUTORS Copyright update for binutils 2016-01-01 23:00:01 +10:30
COPYING
debug.c Copyright update for binutils 2016-01-01 23:00:01 +10:30
dep-in.sed
depend.c use XNEW and related macros more 2016-04-03 20:43:23 -04:00
dw2gencfi.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
dw2gencfi.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
dwarf2dbg.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
dwarf2dbg.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
ecoff.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
ecoff.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
ehopt.c Copyright update for binutils 2016-01-01 23:00:01 +10:30
emul-target.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
emul.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
expr.c use xstrdup, xmemdup0 and concat more 2016-05-13 00:35:51 -04:00
expr.h Add more const type qualifiers to GAS sources. 2016-02-22 14:11:27 +00:00
flonum-copy.c Copyright update for binutils 2016-01-01 23:00:01 +10:30
flonum-konst.c Copyright update for binutils 2016-01-01 23:00:01 +10:30
flonum-mult.c Copyright update for binutils 2016-01-01 23:00:01 +10:30
flonum.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
frags.c Add more const type qualifiers to GAS sources. 2016-02-22 14:11:27 +00:00
frags.h Add more const type qualifiers to GAS sources. 2016-02-22 14:11:27 +00:00
gdbinit.in
hash.c use XNEW and related macros more 2016-04-03 20:43:23 -04:00
hash.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
input-file.c use XNEW and related macros more 2016-04-03 20:43:23 -04:00
input-file.h Add more const type qualifiers to GAS sources. 2016-02-22 14:11:27 +00:00
input-scrub.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
itbl-lex-wrapper.c Copyright update for binutils 2016-01-01 23:00:01 +10:30
itbl-lex.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
itbl-lex.l Copyright update for binutils 2016-01-01 23:00:01 +10:30
itbl-ops.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
itbl-ops.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
itbl-parse.y fixup another old style function definition 2016-06-05 23:49:03 -04:00
listing.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
listing.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
literal.c get rid of K&R style args 2016-03-31 01:04:00 -04:00
macro.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
macro.h Add more const type qualifiers to GAS sources. 2016-02-22 14:11:27 +00:00
MAINTAINERS Copyright update for binutils 2016-01-01 23:00:01 +10:30
Makefile.am enable -Wwrite-strings for gas 2016-03-31 07:30:56 -04:00
Makefile.in Regenerate Makefile.in/aclocal.m4 automake 1.11.6 2016-04-15 16:20:55 -07:00
makefile.vms Copyright update for binutils 2016-01-01 23:00:01 +10:30
messages.c GAS: Fix a typo in `as_bad' description 2016-04-09 13:22:54 +01:00
NEWS Allow ARC target to be configured with --with-cpu=<cpu-name>. 2016-06-30 11:14:41 +01:00
obj.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
output-file.c Add more const type qualifiers to GAS sources. 2016-02-22 14:11:27 +00:00
output-file.h Add more const type qualifiers to GAS sources. 2016-02-22 14:11:27 +00:00
read.c PR19896, Segmentation fault on bad input 2016-04-02 17:31:36 +10:30
read.h Add const qualifiers at various places. 2016-03-07 15:16:28 +00:00
README Copyright update for binutils 2016-01-01 23:00:01 +10:30
remap.c use XNEW and related macros more 2016-04-03 20:43:23 -04:00
sb.c replace some raw xmalloc / xrealloc with the XNEW* macros 2016-03-22 19:06:39 -04:00
sb.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
stabs.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
stamp-h.in
struc-symbol.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
subsegs.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
subsegs.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
symbols.c use XNEW and related macros more 2016-05-13 00:35:51 -04:00
symbols.h Copyright update for binutils 2016-01-01 23:00:01 +10:30
tc.h cleanup FLT_CHARS and EXP_CHARS 2016-04-03 19:50:02 -04:00
write.c PR gas/20312: Do not pad sections to alignment on failed assembly 2016-06-30 15:11:23 +01:00
write.h Add more const type qualifiers to GAS sources. 2016-02-22 14:11:27 +00:00

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 GAS

A number of things have changed since version 1 and the wonderful
world of gas looks very different.  There's still a lot of irrelevant
garbage lying around that will be cleaned up in time.  Documentation
is scarce, as are logs of the changes made since the last gas release.
My apologies, and I'll try to get something useful.

Unpacking and Installation - Summary
====================================

See ../binutils/README.

To build just the assembler, make the target all-gas.

Documentation
=============

The GAS release includes texinfo source for its manual, which can be processed
into `info' or `dvi' forms.

The DVI form is suitable for printing or displaying; the commands for doing
this vary from system to system.  On many systems, `lpr -d' will print a DVI
file.  On others, you may need to run a program such as `dvips' to convert the
DVI file into a form your system can print.

If you wish to build the DVI file, you will need to have TeX installed on your
system.  You can rebuild it by typing:

	cd gas/doc
	make as.dvi

The Info form is viewable with the GNU Emacs `info' subsystem, or the
stand-alone `info' program, available as part of the GNU Texinfo distribution.
To build the info files, you will need the `makeinfo' program.  Type:

	cd gas/doc
	make info

Specifying names for hosts and targets
======================================

   The specifications used for hosts and targets in the `configure'
script are based on a three-part naming scheme, but some short
predefined aliases are also supported.  The full naming scheme encodes
three pieces of information in the following pattern:

     ARCHITECTURE-VENDOR-OS

   For example, you can use the alias `sun4' as a HOST argument or in a
`--target=TARGET' option.  The equivalent full name is
`sparc-sun-sunos4'.

   The `configure' script accompanying GAS does not provide any query
facility to list all supported host and target names or aliases.
`configure' calls the Bourne shell script `config.sub' to map
abbreviations to full names; you can read the script, if you wish, or
you can use it to test your guesses on abbreviations--for example:

     % sh config.sub i386v
     i386-unknown-sysv
     % sh config.sub i786v
     Invalid configuration `i786v': machine `i786v' not recognized


`configure' options
===================

   Here is a summary of the `configure' options and arguments that are
most often useful for building GAS.  `configure' also has several other
options not listed here.

     configure [--help]
               [--prefix=DIR]
               [--srcdir=PATH]
               [--host=HOST]
               [--target=TARGET]
               [--with-OPTION]
               [--enable-OPTION]

You may introduce options with a single `-' rather than `--' if you
prefer; but you may abbreviate option names if you use `--'.

`--help'
     Print a summary of the options to `configure', and exit.

`-prefix=DIR'
     Configure the source to install programs and files under directory
     `DIR'.

`--srcdir=PATH'
     Look for the package's source code in directory DIR.  Usually
     `configure' can determine that directory automatically.

`--host=HOST'
     Configure GAS to run on the specified HOST.  Normally the
     configure script can figure this out automatically.

     There is no convenient way to generate a list of all available
     hosts.

`--target=TARGET'
     Configure GAS for cross-assembling programs for the specified
     TARGET.  Without this option, GAS is configured to assemble .o files
     that run on the same machine (HOST) as GAS itself.

     There is no convenient way to generate a list of all available
     targets.

`--enable-OPTION'
     These flags tell the program or library being configured to
     configure itself differently from the default for the specified
     host/target combination.  See below for a list of `--enable'
     options recognized in the gas distribution.

`configure' accepts other options, for compatibility with configuring
other GNU tools recursively; but these are the only options that affect
GAS or its supporting libraries.

The `--enable' options recognized by software in the gas distribution are:

`--enable-targets=...'
     This causes one or more specified configurations to be added to those for
     which BFD support is compiled.  Currently gas cannot use any format other
     than its compiled-in default, so this option is not very useful.

`--enable-bfd-assembler'
     This causes the assembler to use the new code being merged into it to use
     BFD data structures internally, and use BFD for writing object files.
     For most targets, this isn't supported yet.  For most targets where it has
     been done, it's already the default.  So generally you won't need to use
     this option.

Compiler Support Hacks
======================

On a few targets, the assembler has been modified to support a feature
that is potentially useful when assembling compiler output, but which
may confuse assembly language programmers.  If assembler encounters a
.word pseudo-op of the form symbol1-symbol2 (the difference of two
symbols), and the difference of those two symbols will not fit in 16
bits, the assembler will create a branch around a long jump to
symbol1, and insert this into the output directly before the next
label: The .word will (instead of containing garbage, or giving an
error message) contain (the address of the long jump)-symbol2.  This
allows the assembler to assemble jump tables that jump to locations
very far away into code that works properly.  If the next label is
more than 32K away from the .word, you lose (silently); RMS claims
this will never happen.  If the -K option is given, you will get a
warning message when this happens.


REPORTING BUGS IN GAS
=====================

Bugs in gas should be reported to:

   bug-binutils@gnu.org.

They may be cross-posted to gcc-bugs@gnu.org if they affect the use of
gas with gcc.  They should not be reported just to gcc-bugs, since not
all of the maintainers read that list.

See ../binutils/README for what we need in a bug report.

Copyright (C) 2012-2016 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.