binutils-gdb/gdb/arch/riscv.h

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gdb/riscv: Add target description support This commit adds target description support for riscv. I've used the split feature approach for specifying the architectural features, and the CSR feature is auto-generated from the riscv-opc.h header file. If the target doesn't provide a suitable target description then GDB will build one by looking at the bfd headers. This commit does not implement target description creation for the Linux or FreeBSD native targets, both of these will need to add read_description methods into their respective target classes, which probe the target features, and then call riscv_create_target_description to build a suitable target description. Until this is done Linux and FreeBSD will get the same default target description based on the bfd that bare-metal targets get. I've only added feature descriptions for 32 and 64 bit registers, 128 bit registers (for RISC-V) are not supported in the reset of GDB yet. This commit removes the special reading of the MISA register in order to establish the target features, this was only used for figuring out the f-register size, and even that wasn't done consistently. We now rely on the target to tell us what size of registers it has (or look in the BFD as a last resort). The result of this is that we should now support RV64 targets with 32-bit float, though I have not extensively tested this combination yet. * Makefile.in (ALL_TARGET_OBS): Add arch/riscv.o. (HFILES_NO_SRCDIR): Add arch/riscv.h. * arch/riscv.c: New file. * arch/riscv.h: New file. * configure.tgt: Add cpu_obs list of riscv, move riscv-tdep.o into this list, and add arch/riscv.o. * features/Makefile: Add riscv features. * features/riscv/32bit-cpu.c: New file. * features/riscv/32bit-cpu.xml: New file. * features/riscv/32bit-csr.c: New file. * features/riscv/32bit-csr.xml: New file. * features/riscv/32bit-fpu.c: New file. * features/riscv/32bit-fpu.xml: New file. * features/riscv/64bit-cpu.c: New file. * features/riscv/64bit-cpu.xml: New file. * features/riscv/64bit-csr.c: New file. * features/riscv/64bit-csr.xml: New file. * features/riscv/64bit-fpu.c: New file. * features/riscv/64bit-fpu.xml: New file. * features/riscv/rebuild-csr-xml.sh: New file. * riscv-tdep.c: Add 'arch/riscv.h' include. (riscv_gdb_reg_names): Delete. (csr_reggroup): New global. (struct riscv_register_alias): Delete. (struct riscv_register_feature): New structure. (riscv_register_aliases): Delete. (riscv_xreg_feature): New global. (riscv_freg_feature): New global. (riscv_virtual_feature): New global. (riscv_csr_feature): New global. (riscv_create_csr_aliases): New function. (riscv_read_misa_reg): Delete. (riscv_has_feature): Delete. (riscv_isa_xlen): Simplify, just return cached xlen. (riscv_isa_flen): Simplify, just return cached flen. (riscv_has_fp_abi): Update for changes in struct gdbarch_tdep. (riscv_register_name): Update to make use of tdesc_register_name. Look up xreg and freg names in the new globals riscv_xreg_feature and riscv_freg_feature. Don't supply csr aliases here. (riscv_fpreg_q_type): Delete. (riscv_register_type): Use tdesc_register_type in almost all cases, override the returned type in a few specific cases only. (riscv_print_one_register_info): Handle errors reading registers. (riscv_register_reggroup_p): Use tdesc_register_in_reggroup_p for registers that are otherwise unknown to GDB. Also check the csr_reggroup. (riscv_print_registers_info): Remove assert about upper register number, and use gdbarch_register_reggroup_p instead of short-cutting. (riscv_find_default_target_description): New function. (riscv_check_tdesc_feature): New function. (riscv_add_reggroups): New function. (riscv_setup_register_aliases): New function. (riscv_init_reggroups): New function. (_initialize_riscv_tdep): Add calls to setup CSR aliases, and setup register groups. Register new riscv debug variable. * riscv-tdep.h: Add 'arch/riscv.h' include. (struct gdbarch_tdep): Remove abi union, and add riscv_gdbarch_features field. Remove cached quad floating point type, and provide initialisation for double type field. * target-descriptions.c (maint_print_c_tdesc_cmd): Add riscv to the list of targets using the feature based target descriptions. * NEWS: Mention target description support. gdb/doc/ChangeLog: * gdb.texinfo (Standard Target Features): Add RISC-V Features sub-section.
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/* Common target-dependent functionality for RISC-V
Copyright (C) 2018-2019 Free Software Foundation, Inc.
gdb/riscv: Add target description support This commit adds target description support for riscv. I've used the split feature approach for specifying the architectural features, and the CSR feature is auto-generated from the riscv-opc.h header file. If the target doesn't provide a suitable target description then GDB will build one by looking at the bfd headers. This commit does not implement target description creation for the Linux or FreeBSD native targets, both of these will need to add read_description methods into their respective target classes, which probe the target features, and then call riscv_create_target_description to build a suitable target description. Until this is done Linux and FreeBSD will get the same default target description based on the bfd that bare-metal targets get. I've only added feature descriptions for 32 and 64 bit registers, 128 bit registers (for RISC-V) are not supported in the reset of GDB yet. This commit removes the special reading of the MISA register in order to establish the target features, this was only used for figuring out the f-register size, and even that wasn't done consistently. We now rely on the target to tell us what size of registers it has (or look in the BFD as a last resort). The result of this is that we should now support RV64 targets with 32-bit float, though I have not extensively tested this combination yet. * Makefile.in (ALL_TARGET_OBS): Add arch/riscv.o. (HFILES_NO_SRCDIR): Add arch/riscv.h. * arch/riscv.c: New file. * arch/riscv.h: New file. * configure.tgt: Add cpu_obs list of riscv, move riscv-tdep.o into this list, and add arch/riscv.o. * features/Makefile: Add riscv features. * features/riscv/32bit-cpu.c: New file. * features/riscv/32bit-cpu.xml: New file. * features/riscv/32bit-csr.c: New file. * features/riscv/32bit-csr.xml: New file. * features/riscv/32bit-fpu.c: New file. * features/riscv/32bit-fpu.xml: New file. * features/riscv/64bit-cpu.c: New file. * features/riscv/64bit-cpu.xml: New file. * features/riscv/64bit-csr.c: New file. * features/riscv/64bit-csr.xml: New file. * features/riscv/64bit-fpu.c: New file. * features/riscv/64bit-fpu.xml: New file. * features/riscv/rebuild-csr-xml.sh: New file. * riscv-tdep.c: Add 'arch/riscv.h' include. (riscv_gdb_reg_names): Delete. (csr_reggroup): New global. (struct riscv_register_alias): Delete. (struct riscv_register_feature): New structure. (riscv_register_aliases): Delete. (riscv_xreg_feature): New global. (riscv_freg_feature): New global. (riscv_virtual_feature): New global. (riscv_csr_feature): New global. (riscv_create_csr_aliases): New function. (riscv_read_misa_reg): Delete. (riscv_has_feature): Delete. (riscv_isa_xlen): Simplify, just return cached xlen. (riscv_isa_flen): Simplify, just return cached flen. (riscv_has_fp_abi): Update for changes in struct gdbarch_tdep. (riscv_register_name): Update to make use of tdesc_register_name. Look up xreg and freg names in the new globals riscv_xreg_feature and riscv_freg_feature. Don't supply csr aliases here. (riscv_fpreg_q_type): Delete. (riscv_register_type): Use tdesc_register_type in almost all cases, override the returned type in a few specific cases only. (riscv_print_one_register_info): Handle errors reading registers. (riscv_register_reggroup_p): Use tdesc_register_in_reggroup_p for registers that are otherwise unknown to GDB. Also check the csr_reggroup. (riscv_print_registers_info): Remove assert about upper register number, and use gdbarch_register_reggroup_p instead of short-cutting. (riscv_find_default_target_description): New function. (riscv_check_tdesc_feature): New function. (riscv_add_reggroups): New function. (riscv_setup_register_aliases): New function. (riscv_init_reggroups): New function. (_initialize_riscv_tdep): Add calls to setup CSR aliases, and setup register groups. Register new riscv debug variable. * riscv-tdep.h: Add 'arch/riscv.h' include. (struct gdbarch_tdep): Remove abi union, and add riscv_gdbarch_features field. Remove cached quad floating point type, and provide initialisation for double type field. * target-descriptions.c (maint_print_c_tdesc_cmd): Add riscv to the list of targets using the feature based target descriptions. * NEWS: Mention target description support. gdb/doc/ChangeLog: * gdb.texinfo (Standard Target Features): Add RISC-V Features sub-section.
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This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef ARCH_RISCV_H
#define ARCH_RISCV_H
#include "common/tdesc.h"
/* The set of RISC-V architectural features that we track that impact how
we configure the actual gdbarch instance. We hold one of these in the
gdbarch_tdep structure, and use it to distinguish between different
RISC-V gdbarch instances.
The information in here ideally comes from the target description,
however, if the target doesn't provide a target description then we will
create a default target description by first populating one of these
based on what we know about the binary being executed, and using that to
drive default target description creation. */
struct riscv_gdbarch_features
{
/* The size of the x-registers in bytes. This is either 4 (RV32), 8
(RV64), or 16 (RV128). No other value is valid. Initialise to the
invalid 0 value so we can spot if one of these is used
uninitialised. */
int xlen = 0;
/* The size of the f-registers in bytes. This is either 4 (RV32), 8
(RV64), or 16 (RV128). This can also hold the value 0 to indicate
that there are no f-registers. No other value is valid. */
int flen = 0;
/* This indicates if hardware floating point abi is in use. If the FLEN
field is 0 then this value _must_ be false. If the FLEN field is
non-zero and this field is false then this indicates the target has
floating point registers, but is still using the soft-float abi. If
this field is true then the hardware floating point abi is in use, and
values are passed in f-registers matching the size of FLEN. */
bool hw_float_abi = false;
/* Equality operator. */
bool operator== (const struct riscv_gdbarch_features &rhs) const
{
return (xlen == rhs.xlen && flen == rhs.flen
&& hw_float_abi == rhs.hw_float_abi);
}
/* Inequality operator. */
bool operator!= (const struct riscv_gdbarch_features &rhs) const
{
return !((*this) == rhs);
}
gdb/riscv: Create each unique target description only once GDB relies on the fact that if two target descriptions have the same contents, then they will be the same object instance (having the same address). One place where this is a requirement is in GDBARCH_LIST_LOOKUP_BY_INFO which is used to find previously created gdbarch objects. In GDBARCH_LIST_LOOKUP_BY_INFO a pointer comparison is made on the gdbarch's target description, if the pointers are different then it is assumed the gdbarches have different, non-compatible target descriptions. Previously we would create duplicate target descriptions in the belief that RISCV_GDBARCH_INIT would spot this duplication and discard the second instance. However, this was incorrect, and instead we ended up creating duplicate gdbarch objects. With this commit every unique feature set will create one and only one target description, the feature set and resulting target description is then cached so that the same target description object can be returned later. Many other target avoid this problem by creating a small number of named target descriptions, and returning one of these. However, we currently have 8 possible target descriptions (32 vs 64 bit for x-reg and f-reg, and h/w or s/w float abi) and creating each of these just to avoid a dynamic cache seems pointless. gdb/ChangeLog: * arch/riscv.h (riscv_gdbarch_features::hash): New method. * arch/riscv.c (struct riscv_gdbarch_features_hasher): New. (riscv_tdesc_cache): New global. (riscv_create_target_description): Look in the cache before creating a new target description.
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/* Used by std::unordered_map to hash feature sets. */
std::size_t hash () const noexcept
{
std::size_t val = ((xlen & 0x1f) << 6
| (flen & 0x1f) << 1
| (hw_float_abi ? 1 : 0));
return val;
}
gdb/riscv: Add target description support This commit adds target description support for riscv. I've used the split feature approach for specifying the architectural features, and the CSR feature is auto-generated from the riscv-opc.h header file. If the target doesn't provide a suitable target description then GDB will build one by looking at the bfd headers. This commit does not implement target description creation for the Linux or FreeBSD native targets, both of these will need to add read_description methods into their respective target classes, which probe the target features, and then call riscv_create_target_description to build a suitable target description. Until this is done Linux and FreeBSD will get the same default target description based on the bfd that bare-metal targets get. I've only added feature descriptions for 32 and 64 bit registers, 128 bit registers (for RISC-V) are not supported in the reset of GDB yet. This commit removes the special reading of the MISA register in order to establish the target features, this was only used for figuring out the f-register size, and even that wasn't done consistently. We now rely on the target to tell us what size of registers it has (or look in the BFD as a last resort). The result of this is that we should now support RV64 targets with 32-bit float, though I have not extensively tested this combination yet. * Makefile.in (ALL_TARGET_OBS): Add arch/riscv.o. (HFILES_NO_SRCDIR): Add arch/riscv.h. * arch/riscv.c: New file. * arch/riscv.h: New file. * configure.tgt: Add cpu_obs list of riscv, move riscv-tdep.o into this list, and add arch/riscv.o. * features/Makefile: Add riscv features. * features/riscv/32bit-cpu.c: New file. * features/riscv/32bit-cpu.xml: New file. * features/riscv/32bit-csr.c: New file. * features/riscv/32bit-csr.xml: New file. * features/riscv/32bit-fpu.c: New file. * features/riscv/32bit-fpu.xml: New file. * features/riscv/64bit-cpu.c: New file. * features/riscv/64bit-cpu.xml: New file. * features/riscv/64bit-csr.c: New file. * features/riscv/64bit-csr.xml: New file. * features/riscv/64bit-fpu.c: New file. * features/riscv/64bit-fpu.xml: New file. * features/riscv/rebuild-csr-xml.sh: New file. * riscv-tdep.c: Add 'arch/riscv.h' include. (riscv_gdb_reg_names): Delete. (csr_reggroup): New global. (struct riscv_register_alias): Delete. (struct riscv_register_feature): New structure. (riscv_register_aliases): Delete. (riscv_xreg_feature): New global. (riscv_freg_feature): New global. (riscv_virtual_feature): New global. (riscv_csr_feature): New global. (riscv_create_csr_aliases): New function. (riscv_read_misa_reg): Delete. (riscv_has_feature): Delete. (riscv_isa_xlen): Simplify, just return cached xlen. (riscv_isa_flen): Simplify, just return cached flen. (riscv_has_fp_abi): Update for changes in struct gdbarch_tdep. (riscv_register_name): Update to make use of tdesc_register_name. Look up xreg and freg names in the new globals riscv_xreg_feature and riscv_freg_feature. Don't supply csr aliases here. (riscv_fpreg_q_type): Delete. (riscv_register_type): Use tdesc_register_type in almost all cases, override the returned type in a few specific cases only. (riscv_print_one_register_info): Handle errors reading registers. (riscv_register_reggroup_p): Use tdesc_register_in_reggroup_p for registers that are otherwise unknown to GDB. Also check the csr_reggroup. (riscv_print_registers_info): Remove assert about upper register number, and use gdbarch_register_reggroup_p instead of short-cutting. (riscv_find_default_target_description): New function. (riscv_check_tdesc_feature): New function. (riscv_add_reggroups): New function. (riscv_setup_register_aliases): New function. (riscv_init_reggroups): New function. (_initialize_riscv_tdep): Add calls to setup CSR aliases, and setup register groups. Register new riscv debug variable. * riscv-tdep.h: Add 'arch/riscv.h' include. (struct gdbarch_tdep): Remove abi union, and add riscv_gdbarch_features field. Remove cached quad floating point type, and provide initialisation for double type field. * target-descriptions.c (maint_print_c_tdesc_cmd): Add riscv to the list of targets using the feature based target descriptions. * NEWS: Mention target description support. gdb/doc/ChangeLog: * gdb.texinfo (Standard Target Features): Add RISC-V Features sub-section.
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};
/* Create and return a target description that is compatible with
FEATURES. */
const target_desc *riscv_create_target_description
gdb/riscv: Add target description support This commit adds target description support for riscv. I've used the split feature approach for specifying the architectural features, and the CSR feature is auto-generated from the riscv-opc.h header file. If the target doesn't provide a suitable target description then GDB will build one by looking at the bfd headers. This commit does not implement target description creation for the Linux or FreeBSD native targets, both of these will need to add read_description methods into their respective target classes, which probe the target features, and then call riscv_create_target_description to build a suitable target description. Until this is done Linux and FreeBSD will get the same default target description based on the bfd that bare-metal targets get. I've only added feature descriptions for 32 and 64 bit registers, 128 bit registers (for RISC-V) are not supported in the reset of GDB yet. This commit removes the special reading of the MISA register in order to establish the target features, this was only used for figuring out the f-register size, and even that wasn't done consistently. We now rely on the target to tell us what size of registers it has (or look in the BFD as a last resort). The result of this is that we should now support RV64 targets with 32-bit float, though I have not extensively tested this combination yet. * Makefile.in (ALL_TARGET_OBS): Add arch/riscv.o. (HFILES_NO_SRCDIR): Add arch/riscv.h. * arch/riscv.c: New file. * arch/riscv.h: New file. * configure.tgt: Add cpu_obs list of riscv, move riscv-tdep.o into this list, and add arch/riscv.o. * features/Makefile: Add riscv features. * features/riscv/32bit-cpu.c: New file. * features/riscv/32bit-cpu.xml: New file. * features/riscv/32bit-csr.c: New file. * features/riscv/32bit-csr.xml: New file. * features/riscv/32bit-fpu.c: New file. * features/riscv/32bit-fpu.xml: New file. * features/riscv/64bit-cpu.c: New file. * features/riscv/64bit-cpu.xml: New file. * features/riscv/64bit-csr.c: New file. * features/riscv/64bit-csr.xml: New file. * features/riscv/64bit-fpu.c: New file. * features/riscv/64bit-fpu.xml: New file. * features/riscv/rebuild-csr-xml.sh: New file. * riscv-tdep.c: Add 'arch/riscv.h' include. (riscv_gdb_reg_names): Delete. (csr_reggroup): New global. (struct riscv_register_alias): Delete. (struct riscv_register_feature): New structure. (riscv_register_aliases): Delete. (riscv_xreg_feature): New global. (riscv_freg_feature): New global. (riscv_virtual_feature): New global. (riscv_csr_feature): New global. (riscv_create_csr_aliases): New function. (riscv_read_misa_reg): Delete. (riscv_has_feature): Delete. (riscv_isa_xlen): Simplify, just return cached xlen. (riscv_isa_flen): Simplify, just return cached flen. (riscv_has_fp_abi): Update for changes in struct gdbarch_tdep. (riscv_register_name): Update to make use of tdesc_register_name. Look up xreg and freg names in the new globals riscv_xreg_feature and riscv_freg_feature. Don't supply csr aliases here. (riscv_fpreg_q_type): Delete. (riscv_register_type): Use tdesc_register_type in almost all cases, override the returned type in a few specific cases only. (riscv_print_one_register_info): Handle errors reading registers. (riscv_register_reggroup_p): Use tdesc_register_in_reggroup_p for registers that are otherwise unknown to GDB. Also check the csr_reggroup. (riscv_print_registers_info): Remove assert about upper register number, and use gdbarch_register_reggroup_p instead of short-cutting. (riscv_find_default_target_description): New function. (riscv_check_tdesc_feature): New function. (riscv_add_reggroups): New function. (riscv_setup_register_aliases): New function. (riscv_init_reggroups): New function. (_initialize_riscv_tdep): Add calls to setup CSR aliases, and setup register groups. Register new riscv debug variable. * riscv-tdep.h: Add 'arch/riscv.h' include. (struct gdbarch_tdep): Remove abi union, and add riscv_gdbarch_features field. Remove cached quad floating point type, and provide initialisation for double type field. * target-descriptions.c (maint_print_c_tdesc_cmd): Add riscv to the list of targets using the feature based target descriptions. * NEWS: Mention target description support. gdb/doc/ChangeLog: * gdb.texinfo (Standard Target Features): Add RISC-V Features sub-section.
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(struct riscv_gdbarch_features features);
#endif /* ARCH_RISCV_H */