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Andrew Burgess 113b7b8142 gdb/riscv: Split ISA and ABI features
The goal of this commit is to allow RV64 binaries compiled for the 'F'
extension to run on a target that supports both the 'F' and 'D'
extensions.

The 'D' extension depends on the 'F' extension and chapter 9 of the
RISC-V ISA manual implies that running a program compiled for 'F' on
a 'D' target should be fine.

To support this the gdbarch now holds two feature sets, one represents
the features that are present on the target, and one represents the
features requested in the ELF flags.

The existing error checks are relaxed slightly to allow binaries
compiled for 32-bit 'F' extension to run on targets with the 64-bit
'D' extension.

A new set of functions called riscv_abi_{xlen,flen} are added to
compliment the existing riscv_isa_{xlen,flen}, and some callers to the
isa functions now call the abi functions when that is appropriate.

In riscv_call_arg_struct two asserts are removed, these asserts no
longer make sense.  The asserts were both like this:

    gdb_assert (TYPE_LENGTH (ainfo->type)
                <= (cinfo->flen + cinfo->xlen));

And were made in two cases, when passing structures like these:

   struct {
     integer field1;
     float   field2;
   };

or,

   struct {
     float   field1;
     integer field2;
   };

When running on an RV64 target which only has 32-bit float then the
integer field could be 64-bits, while if the float field is 32-bits
the overall size of the structure can be 128-bits (with 32-bits of
padding).  In this case the assertion would fail, however, the code
isn't incorrect, so its safe to just remove the assertion.

This was tested by running on an RV64IMFDC target using a compiler
configured for RV64IMFC, and comparing the results with those obtained
when using a compiler configured for RV64IMFDC.  The only regressions
I see (now) are in gdb.base/store.exp and are related too different
code generation choices GCC makes between the two targets.

Finally, this commit does not make any attempt to support running
binaries compiled for RV32 on an RV64 target, though nothing in here
should prevent that being supported in the future.

gdb/ChangeLog:

	* arch/riscv.h (struct riscv_gdbarch_features) <hw_float_abi>:
	Delete.
	<operator==>: Update with for removed field.
	<hash>: Likewise.
	* riscv-tdep.h (struct gdbarch_tdep) <features>: Renamed to...
	<isa_features>: ...this.
	<abi_features>: New field.
	(riscv_isa_flen): Update comment.
	(riscv_abi_xlen): New declaration.
	(riscv_abi_flen): New declaration.
	* riscv-tdep.c (riscv_isa_xlen): Update to get answer from
	isa_features.
	(riscv_abi_xlen): New function.
	(riscv_isa_flen): Update to get answer from isa_features.
	(riscv_abi_flen): New function.
	(riscv_has_fp_abi): Update to get answer from abi_features.
	(riscv_call_info::riscv_call_info): Use abi xlen and flen, not isa
	xlen and flen.
	(riscv_call_info) <xlen, flen>: Update comment.
	(riscv_call_arg_struct): Remove invalid assertions
	(riscv_features_from_gdbarch_info): Update now hw_float_abi field
	is removed.
	(riscv_gdbarch_init): Gather isa features and abi features
	separately, ensure both match on the gdbarch when reusing an old
	gdbarch.  Relax an error check to allow 32-bit abi float to run on
	a target with 64-bit float hardware.
2019-01-01 22:56:16 +00:00
bfd Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
binutils Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
config Fix a typo in iconv.m4. 2018-11-09 16:08:10 +00:00
contrib
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elfcpp Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
etc Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
gas Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
gdb gdb/riscv: Split ISA and ABI features 2019-01-01 22:56:16 +00:00
gold Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
gprof Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
include Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
intl Fix a typo in iconv.m4. 2018-11-09 16:08:10 +00:00
ld Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
libdecnumber
libiberty Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
opcodes Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
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sim Update copyright year range in all GDB files. 2019-01-01 10:01:51 +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.