No description
Find a file
Maciej W. Rozycki 92281a5b06 MIPS/opcodes: Address issues with NAL disassembly
Address issues with the disassembly of the NAL assembly idiom and R6
instruction introduced with commit 7361da2c95 ("Add support for MIPS
R6.") and then further tweaked with commit b9121b573e ("Add in a JALRC
alias and fix the NAL instruction.").  As from R6 this instruction has
replaced the encoding of `bltzal $0, . + 4' as the solely supported form
of the former BLTZAL instruction for the regular MIPS ISA.

The instruction is marked as an alias only in our regular MIPS opcode
table, making it fail to disassemble in R6 code if the `no-aliases'
machine option has been passed to `objdump':

$ cat test.s
	.text
foo:
	nal
$ as -mips64r6 -o test.o test.s
$ objdump -dr --prefix-addresses --show-raw-insn -M no-aliases test.o

nal.o:     file format elf32-tradbigmips

Disassembly of section .text:
00000000 <foo> 04100000 	0x4100000
	...
$

This is because the `bltzal' entry has been marked as pre-R6 only in the
opcode table and there is no other opcode pattern to match.

Additionally the changes referred made NAL replace the equivalent
`bltzal $0, . + 4' instruction in disassembly, unless the `no-aliases'
machine option has been used, in legacy code.  Seeing NAL, especially in
its updated form lacking the branch target argument, in the disassembly
of such code may be confusing to people.  This is because unlike with
EHB only used in R2 and newer code -- the machine encoding of which we
anyway always disassemble to its corresponding current architecture's
mnemonic rather than its legacy meaning of `sll $0, $0, 3' -- BLTZAL has
been indeed used in legacy code.  Even though `bltzal $0, . + 8' and its
machine code encoding (0x04100001) -- which is not equivalent to NAL and
still disassembles as BLTZAL -- has been the predominant form as opposed
to NAL's `bltzal $0, . + 4' (0x04100000), it makes sense to always keep
the old form in disassembly, while still accepting `nal' in assembly.

Remove the alias marking then from the the `nal' instruction pattern,
making it always match for R6 code, even with the `no-aliases' option.
And move the entry beyond the `bltzal' entry, making the latter one take
precedence for legacy binary code, while letting the former still match
any `nal' mnemonic in source code assembled for a legacy target.

Add a suitable test case to the GAS test suite.  While the change
affects the disassembler more than the assembler, so placing the test
case in the binutils test suite might be more appropriate, the intent is
also to verify that `nal' is still accepted by GAS for legacy targets,
plus we have test infrastructure available in the GAS test suite for
automatic multiple ISA level testing, which we lack from the binutils
framework.

	opcodes/
	* mips-opc.c (mips_builtin_opcodes): Remove the INSN2_ALIAS
	annotation from the "nal" entry and reorder it beyond "bltzal".

	gas/
	* testsuite/gas/mips/nal-1.d: New test.
	* testsuite/gas/mips/mipsr6@nal-1.d: New test.
	* testsuite/gas/mips/nal-2.d: New test.
	* testsuite/gas/mips/mipsr6@nal-2.d: New test.
	* testsuite/gas/mips/nal.s: New test source.
	* testsuite/gas/mips/mips.exp: Run the new tests.
2016-07-13 17:42:43 +01:00
bfd Automatic date update in version.in 2016-07-13 00:00:19 +00:00
binutils PR20337, Objdump makes poor choice of symbols 2016-07-09 16:53:33 +09:30
config Sync top level files with gcc. 2016-02-10 10:54:29 +00:00
cpu Correct fr30 comment 2016-03-03 12:55:30 +10:30
elfcpp Add support for MIPS .rld_map section. 2016-06-20 12:16:26 -07:00
etc Fix compile time warning messages building with gcc v6.1.1 2016-06-13 10:49:26 +01:00
gas MIPS/opcodes: Address issues with NAL disassembly 2016-07-13 17:42:43 +01:00
gdb [ppc64] Fix for function descriptors 2016-07-13 13:58:19 +02:00
gold Fix gold testsuite failure with GCC 6. 2016-06-29 23:24:35 -07:00
gprof Regenerate configure 2016-05-09 17:24:30 +09:30
include Fixes done to TLS. 2016-07-11 15:24:35 +02:00
intl Regen intl/configure 2015-08-31 12:53:36 +09:30
ld [ARC] Update test. 2016-07-11 15:41:23 +02:00
libdecnumber Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
libiberty Don't needlessly clear xmemdup allocated memory. 2016-05-31 20:34:47 +09:30
opcodes MIPS/opcodes: Address issues with NAL disassembly 2016-07-13 17:42:43 +01:00
readline Revert "Sync readline/ to version 7.0 alpha" 2015-07-25 15:57:00 -04:00
sim Add support for simulating big-endian AArch64 binaries. 2016-06-30 09:10:41 +01:00
texinfo
zlib Regenerate configure 2016-05-09 17:24:30 +09:30
.cvsignore
.gitattributes Add a .gitattributes file for use with git-merge-changelog 2014-07-25 18:07:23 -04:00
.gitignore Import changes made to files shared with the FSF GCC project. 2016-01-11 11:06:56 +00:00
ChangeLog [TILEPro] Don't build gdb 2016-06-28 14:16:15 -04:00
compile Update from upstream Automake 2014-11-16 13:43:48 +01:00
config-ml.in Sync toplevel files with GCC 2015-07-27 07:49:05 -07:00
config.guess Fix typo introduced during the most recent synchronization update. 2016-05-27 14:34:06 +01:00
config.rpath
config.sub Sync config.guess and config.sub with FSF GCC mainline versions 2016-05-23 11:42:17 +01:00
configure [TILEPro] Don't build gdb 2016-06-28 14:16:15 -04:00
configure.ac [TILEPro] Don't build gdb 2016-06-28 14:16:15 -04:00
COPYING
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB
COPYING3
COPYING3.LIB
depcomp Update from upstream Automake 2014-11-16 13:43:48 +01:00
djunpack.bat
install-sh Update from upstream Automake 2014-11-16 13:43:48 +01:00
libtool.m4 Sync top-level btool.m4 with GCC 2016-01-12 08:44:52 -08:00
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
lt~obsolete.m4
MAINTAINERS Update description of ownership of files in include/ 2014-11-04 16:14:14 -08:00
Makefile.def Sync top-level Makefile.def with GCC 2016-01-12 08:34:40 -08:00
Makefile.in Add dependencies to configure rule 2016-05-28 22:36:04 +09:30
Makefile.tpl Add dependencies to configure rule 2016-05-28 22:36:04 +09:30
makefile.vms
missing Update from upstream Automake 2014-11-16 13:43:48 +01:00
mkdep
mkinstalldirs Update from upstream Automake 2014-11-16 13:43:48 +01:00
move-if-change Update `move-if-change' from gnulib 2014-11-16 17:04:02 +01:00
README
README-maintainer-mode
setup.com
src-release.sh fix gdb version parsing in src-release.sh 2016-01-17 10:01:55 +04:00
symlink-tree
ylwrap Update from upstream Automake 2014-11-16 13:43:48 +01:00

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.