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John Baldwin f37bc8b13c Use the existing instruction to determine the RISC-V breakpoint kind.
RISC-V supports instructions of varying lengths.  Standard existing
instructions in the base ISA are 4 bytes in length, but the 'C'
extension adds support for compressed, 2 byte instructions.  RISC-V
supports two different breakpoint instructions: EBREAK is a 4 byte
instruction in the base ISA, and C.EBREAK is a 2 byte instruction only
available on processors implementing the 'C' extension.  Using EBREAK
to set breakpoints on compressed instructions causes problems as the
second half of EBREAK will overwrite the first 2 bytes of the
following instruction breaking other threads in the process if their
PC is the following instruction.  Thus, breakpoints on compressed
instructions need to use C.EBREAK instead of EBREAK.

Previously, the riscv architecture checked the MISA register to
determine if the 'C' extension was available.  If so, it used C.EBREAK
for all breakpoints.  However, the MISA register is not necessarily
available to supervisor mode operating systems.  While native targets
could provide a fake MISA register value, this patch instead examines
the existing instruction at a breakpoint target to determine which
breakpoint instruction to use.  If the existing instruction is a
compressed instruction, C.EBREAK is used, otherwise EBREAK is used.

gdb/ChangeLog:

	* disasm-selftests.c (print_one_insn_test): Add bfd_arch_riscv to
	case with explicit breakpoint kind.
	* riscv-tdep.c (show_use_compressed_breakpoints): Remove
	'additional_info' and related logic.
	(riscv_debug_breakpoints): New variable.
	(riscv_breakpoint_kind_from_pc): Use the length of the existing
	instruction to determine the breakpoint kind.
	(_initialize_riscv_tdep): Add 'set/show debug riscv breakpoints'
	flag.  Update description of 'set/show riscv
	use-compressed-breakpoints' flag.
2018-09-28 14:15:54 -07:00
bfd RISC-V: Pc-rel to gp-rel relaxation function cleanup. 2018-09-27 17:16:34 -07:00
binutils Revert part of commit 32ec889602 2018-09-22 08:46:20 +09:30
config
contrib
cpu
elfcpp
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gas Skip broken assembler test on Windows host. 2018-09-26 09:45:56 -07:00
gdb Use the existing instruction to determine the RISC-V breakpoint kind. 2018-09-28 14:15:54 -07:00
gold
gprof
include ELF: Don't include zero size sections at start of PT_NOTE segment 2018-09-21 04:08:01 -07:00
intl
ld Couple of minor tweaks to the linker testsuite. 2018-09-25 08:15:36 +02:00
libdecnumber
libiberty
opcodes Fix incorrect extraction of signed constants in nios2 disassembler. 2018-09-23 12:31:23 -07:00
readline
sim Change "xor" name in cpu_core to allow building with iso646.h or C++ compiler 2018-09-28 16:00:46 -04:00
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		   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.