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- /* Target-dependent code for the LoongArch architecture, for GDB.
- Copyright (C) 2022 Free Software Foundation, Inc.
- 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/>. */
- #include "defs.h"
- #include "arch-utils.h"
- #include "dwarf2/frame.h"
- #include "elf-bfd.h"
- #include "frame-unwind.h"
- #include "loongarch-tdep.h"
- #include "target-descriptions.h"
- #include "trad-frame.h"
- #include "user-regs.h"
- /* Implement the loongarch_skip_prologue gdbarch method. */
- static CORE_ADDR
- loongarch_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
- {
- CORE_ADDR func_addr;
- /* See if we can determine the end of the prologue via the symbol table.
- If so, then return either PC, or the PC after the prologue, whichever
- is greater. */
- if (find_pc_partial_function (pc, nullptr, &func_addr, nullptr))
- {
- CORE_ADDR post_prologue_pc
- = skip_prologue_using_sal (gdbarch, func_addr);
- if (post_prologue_pc != 0)
- return std::max (pc, post_prologue_pc);
- }
- return 0;
- }
- /* Adjust the address downward (direction of stack growth) so that it
- is correctly aligned for a new stack frame. */
- static CORE_ADDR
- loongarch_frame_align (struct gdbarch *gdbarch, CORE_ADDR addr)
- {
- return align_down (addr, 16);
- }
- /* Generate, or return the cached frame cache for LoongArch frame unwinder. */
- static struct trad_frame_cache *
- loongarch_frame_cache (struct frame_info *this_frame, void **this_cache)
- {
- struct gdbarch *gdbarch = get_frame_arch (this_frame);
- struct trad_frame_cache *cache;
- CORE_ADDR pc;
- if (*this_cache != nullptr)
- return (struct trad_frame_cache *) *this_cache;
- cache = trad_frame_cache_zalloc (this_frame);
- *this_cache = cache;
- loongarch_gdbarch_tdep *tdep = (loongarch_gdbarch_tdep *) gdbarch_tdep (gdbarch);
- trad_frame_set_reg_realreg (cache, gdbarch_pc_regnum (gdbarch), tdep->regs.ra);
- pc = get_frame_address_in_block (this_frame);
- trad_frame_set_id (cache, frame_id_build_unavailable_stack (pc));
- return cache;
- }
- /* Implement the this_id callback for LoongArch frame unwinder. */
- static void
- loongarch_frame_this_id (struct frame_info *this_frame, void **prologue_cache,
- struct frame_id *this_id)
- {
- struct trad_frame_cache *info;
- info = loongarch_frame_cache (this_frame, prologue_cache);
- trad_frame_get_id (info, this_id);
- }
- /* Implement the prev_register callback for LoongArch frame unwinder. */
- static struct value *
- loongarch_frame_prev_register (struct frame_info *this_frame,
- void **prologue_cache, int regnum)
- {
- struct trad_frame_cache *info;
- info = loongarch_frame_cache (this_frame, prologue_cache);
- return trad_frame_get_register (info, this_frame, regnum);
- }
- static const struct frame_unwind loongarch_frame_unwind = {
- "loongarch prologue",
- /*.type =*/NORMAL_FRAME,
- /*.stop_reason =*/default_frame_unwind_stop_reason,
- /*.this_id =*/loongarch_frame_this_id,
- /*.prev_register =*/loongarch_frame_prev_register,
- /*.unwind_data =*/nullptr,
- /*.sniffer =*/default_frame_sniffer,
- /*.dealloc_cache =*/nullptr,
- /*.prev_arch =*/nullptr,
- };
- /* Implement the "dwarf2_reg_to_regnum" gdbarch method. */
- static int
- loongarch_dwarf2_reg_to_regnum (struct gdbarch *gdbarch, int num)
- {
- loongarch_gdbarch_tdep *tdep = (loongarch_gdbarch_tdep *) gdbarch_tdep (gdbarch);
- auto regs = tdep->regs;
- if (0 <= num && num < 32)
- return regs.r + num;
- else
- return -1;
- }
- static constexpr gdb_byte loongarch_default_breakpoint[] = {0x05, 0x00, 0x2a, 0x00};
- typedef BP_MANIPULATION (loongarch_default_breakpoint) loongarch_breakpoint;
- /* Extract a set of required target features out of ABFD. If ABFD is nullptr
- then a LOONGARCH_GDBARCH_FEATURES is returned in its default state. */
- static struct loongarch_gdbarch_features
- loongarch_features_from_bfd (const bfd *abfd)
- {
- struct loongarch_gdbarch_features features;
- /* Now try to improve on the defaults by looking at the binary we are
- going to execute. We assume the user knows what they are doing and
- that the target will match the binary. Remember, this code path is
- only used at all if the target hasn't given us a description, so this
- is really a last ditched effort to do something sane before giving
- up. */
- if (abfd != nullptr && bfd_get_flavour (abfd) == bfd_target_elf_flavour)
- {
- unsigned char eclass = elf_elfheader (abfd)->e_ident[EI_CLASS];
- if (eclass == ELFCLASS32)
- features.xlen = 4;
- else if (eclass == ELFCLASS64)
- features.xlen = 8;
- else
- internal_error (__FILE__, __LINE__,
- _("unknown ELF header class %d"), eclass);
- }
- return features;
- }
- /* Find a suitable default target description. Use the contents of INFO,
- specifically the bfd object being executed, to guide the selection of a
- suitable default target description. */
- static const struct target_desc *
- loongarch_find_default_target_description (const struct gdbarch_info info)
- {
- /* Extract desired feature set from INFO. */
- struct loongarch_gdbarch_features features
- = loongarch_features_from_bfd (info.abfd);
- /* If the XLEN field is still 0 then we got nothing useful from INFO.BFD,
- maybe there was no bfd object. In this case we fall back to a minimal
- useful target with no floating point, the x-register size is selected
- based on the architecture from INFO. */
- if (features.xlen == 0)
- features.xlen = info.bfd_arch_info->bits_per_address == 32 ? 4 : 8;
- /* Now build a target description based on the feature set. */
- return loongarch_lookup_target_description (features);
- }
- /* Initialize the current architecture based on INFO */
- static struct gdbarch *
- loongarch_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
- {
- const struct target_desc *tdesc = info.target_desc;
- /* Ensure we always have a target description. */
- if (!tdesc_has_registers (tdesc))
- tdesc = loongarch_find_default_target_description (info);
- const struct tdesc_feature *feature_cpu
- = tdesc_find_feature (tdesc, "org.gnu.gdb.loongarch.base");
- if (feature_cpu == nullptr)
- return nullptr;
- int xlen_bitsize = tdesc_register_bitsize (feature_cpu, "pc");
- struct loongarch_gdbarch_features features;
- features.xlen = (xlen_bitsize / 8);
- size_t regnum = 0;
- tdesc_arch_data_up tdesc_data = tdesc_data_alloc ();
- loongarch_gdbarch_tdep *tdep = new loongarch_gdbarch_tdep;
- tdep->regs.r = regnum;
- /* Validate the description provides the mandatory base registers
- and allocate their numbers. */
- bool valid_p = true;
- for (int i = 0; i < 32; i++)
- valid_p &= tdesc_numbered_register (feature_cpu, tdesc_data.get (), regnum++,
- loongarch_r_normal_name[i] + 1);
- valid_p &= tdesc_numbered_register (feature_cpu, tdesc_data.get (),
- tdep->regs.pc = regnum++, "pc");
- valid_p &= tdesc_numbered_register (feature_cpu, tdesc_data.get (),
- tdep->regs.badv = regnum++, "badv");
- if (!valid_p)
- return nullptr;
- /* LoongArch code is always little-endian. */
- info.byte_order_for_code = BFD_ENDIAN_LITTLE;
- /* Have a look at what the supplied (if any) bfd object requires of the
- target, then check that this matches with what the target is
- providing. */
- struct loongarch_gdbarch_features abi_features
- = loongarch_features_from_bfd (info.abfd);
- /* If the ABI_FEATURES xlen is 0 then this indicates we got no useful abi
- features from the INFO object. In this case we just treat the
- hardware features as defining the abi. */
- if (abi_features.xlen == 0)
- abi_features = features;
- /* Find a candidate among the list of pre-declared architectures. */
- for (arches = gdbarch_list_lookup_by_info (arches, &info);
- arches != nullptr;
- arches = gdbarch_list_lookup_by_info (arches->next, &info))
- {
- /* Check that the feature set of the ARCHES matches the feature set
- we are looking for. If it doesn't then we can't reuse this
- gdbarch. */
- loongarch_gdbarch_tdep *candidate_tdep
- = (loongarch_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
- if (candidate_tdep->abi_features != abi_features)
- continue;
- break;
- }
- if (arches != nullptr)
- return arches->gdbarch;
- /* None found, so create a new architecture from the information provided. */
- struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep);
- tdep->abi_features = abi_features;
- /* Target data types. */
- set_gdbarch_short_bit (gdbarch, 16);
- set_gdbarch_int_bit (gdbarch, 32);
- set_gdbarch_long_bit (gdbarch, info.bfd_arch_info->bits_per_address);
- set_gdbarch_long_long_bit (gdbarch, 64);
- set_gdbarch_float_bit (gdbarch, 32);
- set_gdbarch_double_bit (gdbarch, 64);
- set_gdbarch_long_double_bit (gdbarch, 128);
- set_gdbarch_long_double_format (gdbarch, floatformats_ieee_quad);
- set_gdbarch_ptr_bit (gdbarch, info.bfd_arch_info->bits_per_address);
- set_gdbarch_char_signed (gdbarch, 0);
- info.target_desc = tdesc;
- info.tdesc_data = tdesc_data.get ();
- /* Information about registers. */
- tdep->regs.ra = tdep->regs.r + 1;
- tdep->regs.sp = tdep->regs.r + 3;
- set_gdbarch_num_regs (gdbarch, regnum);
- set_gdbarch_sp_regnum (gdbarch, tdep->regs.sp);
- set_gdbarch_pc_regnum (gdbarch, tdep->regs.pc);
- /* Finalise the target description registers. */
- tdesc_use_registers (gdbarch, tdesc, std::move (tdesc_data));
- /* Advance PC across function entry code. */
- set_gdbarch_skip_prologue (gdbarch, loongarch_skip_prologue);
- /* Stack grows downward. */
- set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
- /* Frame info. */
- set_gdbarch_frame_align (gdbarch, loongarch_frame_align);
- /* Breakpoint manipulation. */
- set_gdbarch_breakpoint_kind_from_pc (gdbarch, loongarch_breakpoint::kind_from_pc);
- set_gdbarch_sw_breakpoint_from_kind (gdbarch, loongarch_breakpoint::bp_from_kind);
- /* Frame unwinders. Use DWARF debug info if available, otherwise use our own unwinder. */
- set_gdbarch_dwarf2_reg_to_regnum (gdbarch, loongarch_dwarf2_reg_to_regnum);
- dwarf2_append_unwinders (gdbarch);
- frame_unwind_append_unwinder (gdbarch, &loongarch_frame_unwind);
- /* Hook in OS ABI-specific overrides, if they have been registered. */
- gdbarch_init_osabi (info, gdbarch);
- return gdbarch;
- }
- void _initialize_loongarch_tdep ();
- void
- _initialize_loongarch_tdep ()
- {
- gdbarch_register (bfd_arch_loongarch, loongarch_gdbarch_init, nullptr);
- }
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