https://github.com/riscv/riscv-asm-manual/pull/67
Format:
.option arch, +<extension><version>, ...
.option arch, -<extension>
.option arch, =<ISA string>
The new direcitve is used to enable/disable extensions for the specific
code region. For example,
.attribute arch, "rv64ic" # arch = rv64i2p0_c2p0
.option push
.option arch, +d2p0, -c # arch = rv64i2p0_f2p0_d2p0, f is added implied
.option arch, =rv32gc # arch = rv32i2p0_m2p0_a2p0_f2p0_d2p0_c2p0
.option pop # arch = rv64i2p0_c2p0
Note that,
1. ".option rvc/norvc" have the same behavior as ".option arch +c/-c".
2. ".option arch -i" is illegal, since we cannot remove base i extension.
3. If arch=rv64i2p0, then ".option arch, +i3p0" will update the i's version
from 2.0 to 3.0.
4. If arch=rv64i3p0, then ".option arch, +i" will update the i's version
from 2.0 to the default one according to the chosen isa spec.
bfd/
* elfxx-riscv.c (riscv_add_subset): If the subset is already added,
and the new versions are not RISCV_UNKNOWN_VERSION, then update the
versions to the subset list.
(riscv_copy_subset): New function. Copy the subset from list.
(riscv_copy_subset_list): New function. Return the new copyed list.
(riscv_update_subset): Updated to make .option arch directives workable.
* elfxx-riscv.h: Updated.
gas/
* config/tc-riscv.c (riscv_subsets): Defined as a pointer.
(riscv_rps_as): Init the subset_list to NULL, we will set it later
once riscv_opts_stack is created or updated.
(struct riscv_option_stack, riscv_opts_stack): Moved forward.
(riscv_set_arch): Updated.
(s_riscv_option): Support new .option arch directive, to add, remove
or update subsets for the specific code region.
(riscv_write_out_attrs): Updated.
* doc/c-riscv.texi: Added document for new .option arch directive.
* testsuite/gas/riscv/option-arch-01a.d: New testcase.
* testsuite/gas/riscv/option-arch-01b.d: Likewise.
* testsuite/gas/riscv/option-arch-01.s: Likewise..
* testsuite/gas/riscv/option-arch-02.d: Likewise.
* testsuite/gas/riscv/option-arch-02.s: Likewise.
* testsuite/gas/riscv/option-arch-fail.d: Likewise.
* testsuite/gas/riscv/option-arch-fail.l: Likewise.
* testsuite/gas/riscv/option-arch-fail.s: Likewise.
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.
BFD is an object file library. It permits applications to use the
same routines to process object files regardless of their format.
BFD is used by the GNU debugger, assembler, linker, and the binary
utilities.
The documentation on using BFD is scanty and may be occasionally
incorrect. Pointers to documentation problems, or an entirely
rewritten manual, would be appreciated.
There is some BFD internals documentation in doc/bfdint.texi which may
help programmers who want to modify BFD.
BFD is normally built as part of another package. See the build
instructions for that package, probably in a README file in the
appropriate directory.
BFD supports the following configure options:
--target=TARGET
The default target for which to build the library. TARGET is
a configuration target triplet, such as sparc-sun-solaris.
--enable-targets=TARGET,TARGET,TARGET...
Additional targets the library should support. To include
support for all known targets, use --enable-targets=all.
--enable-64-bit-bfd
Include support for 64 bit targets. This is automatically
turned on if you explicitly request a 64 bit target, but not
for --enable-targets=all. This requires a compiler with a 64
bit integer type, such as gcc.
--enable-shared
Build BFD as a shared library.
--with-mmap
Use mmap when accessing files. This is faster on some hosts,
but slower on others. It may not work on all hosts.
Report bugs with BFD to bug-binutils@gnu.org.
Patches are encouraged. When sending patches, always send the output
of diff -u or diff -c from the original file to the new file. Do not
send default diff output. Do not make the diff from the new file to
the original file. Remember that any patch must not break other
systems. Remember that BFD must support cross compilation from any
host to any target, so patches which use ``#ifdef HOST'' are not
acceptable. Please also read the ``Reporting Bugs'' section of the
gcc manual.
Bug reports without patches will be remembered, but they may never get
fixed until somebody volunteers to fix them.
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.
d3ffd7f776