There are two main reasons for this patch,
* In the past we had two extension tables, one is used to record all
supported extensions in bfd/elfxx-riscv.c, another is used to get the
default extension versions in gas/config/tc-riscv.c. It is hard to
maintain lots of tables in different files, but in fact we can merge
them into just one table. Therefore, we now define many riscv_supported_std*
tables, which record names and versions for all supported extensions.
We not only use these tables to initialize the riscv_ext_order, but
also use them to get the default versions of extensions, and decide if
the extensions should be enbaled by default.
* We add a new filed `default_enable' for the riscv_supported_std* tables,
to decide if the extension should be enabled by default. For now if the
`default_enable' field of the extension is set to EXT_DEFAULT, then we
should enable the extension when the -march and elf architecture attributes
are not set. In the future, I suppose the `default_enable' can be set
to lots of EXT_<VENDOR>, each vendor can decide to open which extensions,
when the target triple of vendor is chosen.
The elf/linux regression tests of riscv-gnu-toolchain are passed.
bfd/
* elfnn-riscv.c (cpu-riscv.h): Removed sine it is included in
bfd/elfxx-riscv.h.
(riscv_merge_std_ext): Updated since the field of rpe is changed.
* elfxx-riscv.c (cpu-riscv.h): Removed.
(riscv_implicit_subsets): Added implicit extensions for g.
(struct riscv_supported_ext): Used to be riscv_ext_version. Moved
from gas/config/tc-riscv.c, and added new field `default_enable' to
decide if the extension should be enabled by default.
(EXT_DEFAULT): Defined for `default_enable' field.
(riscv_supported_std_ext): It used to return the supported standard
architecture string, but now we move ext_version_table from
gas/config/tc-riscv.c to here, and rename it to riscv_supported_std_ext.
Currently we not only use the table to initialize riscv_ext_order, but
also get the default versions of extensions, and decide if the extensions
should be enbaled by default.
(riscv_supported_std_z_ext): Likewise, but is used for z* extensions.
(riscv_supported_std_s_ext): Likewise, but is used for s* extensions.
(riscv_supported_std_h_ext): Likewise, but is used for h* extensions.
(riscv_supported_std_zxm_ext): Likewise, but is used for zxm* extensions.
(riscv_all_supported_ext): Includes all supported extension tables.
(riscv_known_prefixed_ext): Updated.
(riscv_valid_prefixed_ext): Updated.
(riscv_init_ext_order): Init the riscv_ext_order table according to
riscv_supported_std_ext.
(riscv_get_default_ext_version): Moved from gas/config/tc-riscv.c.
Get the versions of extensions from riscv_supported_std* tables.
(riscv_parse_add_subset): Updated.
(riscv_parse_std_ext): Updated.
(riscv_set_default_arch): Set the default subset list according to
the default_enable field of riscv_supported_*ext tables.
(riscv_parse_subset): If the input ARCH is NULL, then we call
riscv_set_default_arch to set the default subset list.
* elfxx-riscv.h (cpu-riscv.h): Included.
(riscv_parse_subset_t): Removed get_default_version field, and added
isa_spec field to replace it.
(extern riscv_supported_std_ext): Removed.
gas/
* (bfd/cpu-riscv.h): Removed.
(struct riscv_ext_version): Renamed and moved to bfd/elfxx-riscv.c.
(ext_version_table): Likewise.
(riscv_get_default_ext_version): Likewise.
(ext_version_hash): Removed.
(init_ext_version_hash): Removed.
(riscv_set_arch): Updated since the field of rps is changed. Besides,
report error when the architecture string is empty.
(riscv_after_parse_args): Updated.
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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) 2012-2021 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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