[1/2] Inline initialization of gdbarch members

  This changes gdbarch to use the "predefault" to initialize its members
inline.  This required changing a couple of the Value instantiations
to avoid a use of "gdbarch" during initialization, but on the whole I
think this is better -- it removes a hidden ordering dependency.
---
 gdb/gdbarch-components.py |   8 +-
 gdb/gdbarch.c             | 290 +++++++++++++-------------------------
 gdb/gdbarch.py            |  19 +--
 3 files changed, 111 insertions(+), 206 deletions(-)
  

On 18/10/2022 18:15, Tom Tromey via Gdb-patches wrote:
> This changes gdbarch to use the "predefault" to initialize its members
> inline.  This required changing a couple of the Value instantiations
> to avoid a use of "gdbarch" during initialization, but on the whole I
> think this is better -- it removes a hidden ordering dependency.

Hi Tom,

I don't really understand gdbarch, so sorry if this is an obvious 
question, but why have you only avoided using gdbarch in Value 
instantiations and kept them in Info instantiations? (lines 120 and 141, 
for instance)

Cheers,
Bruno

> ---
>   gdb/gdbarch-components.py |   8 +-
>   gdb/gdbarch.c             | 290 +++++++++++++-------------------------
>   gdb/gdbarch.py            |  19 +--
>   3 files changed, 111 insertions(+), 206 deletions(-)
>
> diff --git a/gdb/gdbarch-components.py b/gdb/gdbarch-components.py
> index 46e7565f293..c997a709cbb 100644
> --- a/gdb/gdbarch-components.py
> +++ b/gdb/gdbarch-components.py
> @@ -151,7 +151,7 @@ Number of bits in a short or unsigned short for the target machine.
>       invalid=False,
>   )
>   
> -Value(
> +int_bit = Value(
>       comment="""
>   Number of bits in an int or unsigned int for the target machine.
>   """,
> @@ -161,7 +161,7 @@ Number of bits in an int or unsigned int for the target machine.
>       invalid=False,
>   )
>   
> -Value(
> +long_bit = Value(
>       comment="""
>   Number of bits in a long or unsigned long for the target machine.
>   """,
> @@ -178,7 +178,7 @@ machine.
>   """,
>       type="int",
>       name="long_long_bit",
> -    predefault="2*gdbarch->long_bit",
> +    predefault="2*" + long_bit.predefault,
>       invalid=False,
>   )
>   
> @@ -314,7 +314,7 @@ ptr_bit is the size of a pointer on the target
>   """,
>       type="int",
>       name="ptr_bit",
> -    predefault="gdbarch->int_bit",
> +    predefault=int_bit.predefault,
>       invalid=False,
>   )
>   
> diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
> index 559e92dee58..5545cfdad8e 100644
> --- a/gdb/gdbarch.c
> +++ b/gdb/gdbarch.c
> @@ -52,124 +52,124 @@ struct gdbarch
>     unsigned nr_data = 0;
>     void **data = nullptr;
>   
> -  int short_bit = 0;
> -  int int_bit = 0;
> -  int long_bit = 0;
> -  int long_long_bit = 0;
> -  int bfloat16_bit = 0;
> +  int short_bit = 2*TARGET_CHAR_BIT;
> +  int int_bit = 4*TARGET_CHAR_BIT;
> +  int long_bit = 4*TARGET_CHAR_BIT;
> +  int long_long_bit = 2*4*TARGET_CHAR_BIT;
> +  int bfloat16_bit = 2*TARGET_CHAR_BIT;
>     const struct floatformat ** bfloat16_format = 0;
> -  int half_bit = 0;
> +  int half_bit = 2*TARGET_CHAR_BIT;
>     const struct floatformat ** half_format = 0;
> -  int float_bit = 0;
> +  int float_bit = 4*TARGET_CHAR_BIT;
>     const struct floatformat ** float_format = 0;
> -  int double_bit = 0;
> +  int double_bit = 8*TARGET_CHAR_BIT;
>     const struct floatformat ** double_format = 0;
> -  int long_double_bit = 0;
> +  int long_double_bit = 8*TARGET_CHAR_BIT;
>     const struct floatformat ** long_double_format = 0;
> -  int wchar_bit = 0;
> -  int wchar_signed = 0;
> -  gdbarch_floatformat_for_type_ftype *floatformat_for_type = nullptr;
> -  int ptr_bit = 0;
> +  int wchar_bit = 4*TARGET_CHAR_BIT;
> +  int wchar_signed = -1;
> +  gdbarch_floatformat_for_type_ftype *floatformat_for_type = default_floatformat_for_type;
> +  int ptr_bit = 4*TARGET_CHAR_BIT;
>     int addr_bit = 0;
>     int dwarf2_addr_size = 0;
> -  int char_signed = 0;
> +  int char_signed = -1;
>     gdbarch_read_pc_ftype *read_pc = nullptr;
>     gdbarch_write_pc_ftype *write_pc = nullptr;
> -  gdbarch_virtual_frame_pointer_ftype *virtual_frame_pointer = nullptr;
> +  gdbarch_virtual_frame_pointer_ftype *virtual_frame_pointer = legacy_virtual_frame_pointer;
>     gdbarch_pseudo_register_read_ftype *pseudo_register_read = nullptr;
>     gdbarch_pseudo_register_read_value_ftype *pseudo_register_read_value = nullptr;
>     gdbarch_pseudo_register_write_ftype *pseudo_register_write = nullptr;
> -  int num_regs = 0;
> +  int num_regs = -1;
>     int num_pseudo_regs = 0;
>     gdbarch_ax_pseudo_register_collect_ftype *ax_pseudo_register_collect = nullptr;
>     gdbarch_ax_pseudo_register_push_stack_ftype *ax_pseudo_register_push_stack = nullptr;
>     gdbarch_report_signal_info_ftype *report_signal_info = nullptr;
> -  int sp_regnum = 0;
> -  int pc_regnum = 0;
> -  int ps_regnum = 0;
> -  int fp0_regnum = 0;
> -  gdbarch_stab_reg_to_regnum_ftype *stab_reg_to_regnum = nullptr;
> -  gdbarch_ecoff_reg_to_regnum_ftype *ecoff_reg_to_regnum = nullptr;
> -  gdbarch_sdb_reg_to_regnum_ftype *sdb_reg_to_regnum = nullptr;
> -  gdbarch_dwarf2_reg_to_regnum_ftype *dwarf2_reg_to_regnum = nullptr;
> -  gdbarch_register_name_ftype *register_name = nullptr;
> +  int sp_regnum = -1;
> +  int pc_regnum = -1;
> +  int ps_regnum = -1;
> +  int fp0_regnum = -1;
> +  gdbarch_stab_reg_to_regnum_ftype *stab_reg_to_regnum = no_op_reg_to_regnum;
> +  gdbarch_ecoff_reg_to_regnum_ftype *ecoff_reg_to_regnum = no_op_reg_to_regnum;
> +  gdbarch_sdb_reg_to_regnum_ftype *sdb_reg_to_regnum = no_op_reg_to_regnum;
> +  gdbarch_dwarf2_reg_to_regnum_ftype *dwarf2_reg_to_regnum = no_op_reg_to_regnum;
> +  gdbarch_register_name_ftype *register_name = 0;
>     gdbarch_register_type_ftype *register_type = nullptr;
> -  gdbarch_dummy_id_ftype *dummy_id = nullptr;
> -  int deprecated_fp_regnum = 0;
> +  gdbarch_dummy_id_ftype *dummy_id = default_dummy_id;
> +  int deprecated_fp_regnum = -1;
>     gdbarch_push_dummy_call_ftype *push_dummy_call = nullptr;
> -  int call_dummy_location = 0;
> +  int call_dummy_location = AT_ENTRY_POINT;
>     gdbarch_push_dummy_code_ftype *push_dummy_code = nullptr;
> -  gdbarch_code_of_frame_writable_ftype *code_of_frame_writable = nullptr;
> -  gdbarch_print_registers_info_ftype *print_registers_info = nullptr;
> -  gdbarch_print_float_info_ftype *print_float_info = nullptr;
> +  gdbarch_code_of_frame_writable_ftype *code_of_frame_writable = default_code_of_frame_writable;
> +  gdbarch_print_registers_info_ftype *print_registers_info = default_print_registers_info;
> +  gdbarch_print_float_info_ftype *print_float_info = default_print_float_info;
>     gdbarch_print_vector_info_ftype *print_vector_info = nullptr;
> -  gdbarch_register_sim_regno_ftype *register_sim_regno = nullptr;
> -  gdbarch_cannot_fetch_register_ftype *cannot_fetch_register = nullptr;
> -  gdbarch_cannot_store_register_ftype *cannot_store_register = nullptr;
> +  gdbarch_register_sim_regno_ftype *register_sim_regno = legacy_register_sim_regno;
> +  gdbarch_cannot_fetch_register_ftype *cannot_fetch_register = cannot_register_not;
> +  gdbarch_cannot_store_register_ftype *cannot_store_register = cannot_register_not;
>     gdbarch_get_longjmp_target_ftype *get_longjmp_target = nullptr;
>     int believe_pcc_promotion = 0;
> -  gdbarch_convert_register_p_ftype *convert_register_p = nullptr;
> +  gdbarch_convert_register_p_ftype *convert_register_p = generic_convert_register_p;
>     gdbarch_register_to_value_ftype *register_to_value = nullptr;
>     gdbarch_value_to_register_ftype *value_to_register = nullptr;
> -  gdbarch_value_from_register_ftype *value_from_register = nullptr;
> -  gdbarch_pointer_to_address_ftype *pointer_to_address = nullptr;
> -  gdbarch_address_to_pointer_ftype *address_to_pointer = nullptr;
> +  gdbarch_value_from_register_ftype *value_from_register = default_value_from_register;
> +  gdbarch_pointer_to_address_ftype *pointer_to_address = unsigned_pointer_to_address;
> +  gdbarch_address_to_pointer_ftype *address_to_pointer = unsigned_address_to_pointer;
>     gdbarch_integer_to_address_ftype *integer_to_address = nullptr;
>     gdbarch_return_value_ftype *return_value = nullptr;
> -  gdbarch_return_in_first_hidden_param_p_ftype *return_in_first_hidden_param_p = nullptr;
> -  gdbarch_skip_prologue_ftype *skip_prologue = nullptr;
> +  gdbarch_return_in_first_hidden_param_p_ftype *return_in_first_hidden_param_p = default_return_in_first_hidden_param_p;
> +  gdbarch_skip_prologue_ftype *skip_prologue = 0;
>     gdbarch_skip_main_prologue_ftype *skip_main_prologue = nullptr;
>     gdbarch_skip_entrypoint_ftype *skip_entrypoint = nullptr;
> -  gdbarch_inner_than_ftype *inner_than = nullptr;
> -  gdbarch_breakpoint_from_pc_ftype *breakpoint_from_pc = nullptr;
> -  gdbarch_breakpoint_kind_from_pc_ftype *breakpoint_kind_from_pc = nullptr;
> -  gdbarch_sw_breakpoint_from_kind_ftype *sw_breakpoint_from_kind = nullptr;
> -  gdbarch_breakpoint_kind_from_current_state_ftype *breakpoint_kind_from_current_state = nullptr;
> +  gdbarch_inner_than_ftype *inner_than = 0;
> +  gdbarch_breakpoint_from_pc_ftype *breakpoint_from_pc = default_breakpoint_from_pc;
> +  gdbarch_breakpoint_kind_from_pc_ftype *breakpoint_kind_from_pc = 0;
> +  gdbarch_sw_breakpoint_from_kind_ftype *sw_breakpoint_from_kind = NULL;
> +  gdbarch_breakpoint_kind_from_current_state_ftype *breakpoint_kind_from_current_state = default_breakpoint_kind_from_current_state;
>     gdbarch_adjust_breakpoint_address_ftype *adjust_breakpoint_address = nullptr;
> -  gdbarch_memory_insert_breakpoint_ftype *memory_insert_breakpoint = nullptr;
> -  gdbarch_memory_remove_breakpoint_ftype *memory_remove_breakpoint = nullptr;
> +  gdbarch_memory_insert_breakpoint_ftype *memory_insert_breakpoint = default_memory_insert_breakpoint;
> +  gdbarch_memory_remove_breakpoint_ftype *memory_remove_breakpoint = default_memory_remove_breakpoint;
>     CORE_ADDR decr_pc_after_break = 0;
>     CORE_ADDR deprecated_function_start_offset = 0;
> -  gdbarch_remote_register_number_ftype *remote_register_number = nullptr;
> +  gdbarch_remote_register_number_ftype *remote_register_number = default_remote_register_number;
>     gdbarch_fetch_tls_load_module_address_ftype *fetch_tls_load_module_address = nullptr;
>     gdbarch_get_thread_local_address_ftype *get_thread_local_address = nullptr;
>     CORE_ADDR frame_args_skip = 0;
> -  gdbarch_unwind_pc_ftype *unwind_pc = nullptr;
> -  gdbarch_unwind_sp_ftype *unwind_sp = nullptr;
> +  gdbarch_unwind_pc_ftype *unwind_pc = default_unwind_pc;
> +  gdbarch_unwind_sp_ftype *unwind_sp = default_unwind_sp;
>     gdbarch_frame_num_args_ftype *frame_num_args = nullptr;
>     gdbarch_frame_align_ftype *frame_align = nullptr;
> -  gdbarch_stabs_argument_has_addr_ftype *stabs_argument_has_addr = nullptr;
> +  gdbarch_stabs_argument_has_addr_ftype *stabs_argument_has_addr = default_stabs_argument_has_addr;
>     int frame_red_zone_size = 0;
> -  gdbarch_convert_from_func_ptr_addr_ftype *convert_from_func_ptr_addr = nullptr;
> -  gdbarch_addr_bits_remove_ftype *addr_bits_remove = nullptr;
> +  gdbarch_convert_from_func_ptr_addr_ftype *convert_from_func_ptr_addr = convert_from_func_ptr_addr_identity;
> +  gdbarch_addr_bits_remove_ftype *addr_bits_remove = core_addr_identity;
>     int significant_addr_bit = 0;
> -  gdbarch_memtag_to_string_ftype *memtag_to_string = nullptr;
> -  gdbarch_tagged_address_p_ftype *tagged_address_p = nullptr;
> -  gdbarch_memtag_matches_p_ftype *memtag_matches_p = nullptr;
> -  gdbarch_set_memtags_ftype *set_memtags = nullptr;
> -  gdbarch_get_memtag_ftype *get_memtag = nullptr;
> +  gdbarch_memtag_to_string_ftype *memtag_to_string = default_memtag_to_string;
> +  gdbarch_tagged_address_p_ftype *tagged_address_p = default_tagged_address_p;
> +  gdbarch_memtag_matches_p_ftype *memtag_matches_p = default_memtag_matches_p;
> +  gdbarch_set_memtags_ftype *set_memtags = default_set_memtags;
> +  gdbarch_get_memtag_ftype *get_memtag = default_get_memtag;
>     CORE_ADDR memtag_granule_size = 0;
>     gdbarch_software_single_step_ftype *software_single_step = nullptr;
>     gdbarch_single_step_through_delay_ftype *single_step_through_delay = nullptr;
> -  gdbarch_print_insn_ftype *print_insn = nullptr;
> -  gdbarch_skip_trampoline_code_ftype *skip_trampoline_code = nullptr;
> +  gdbarch_print_insn_ftype *print_insn = default_print_insn;
> +  gdbarch_skip_trampoline_code_ftype *skip_trampoline_code = generic_skip_trampoline_code;
>     const struct target_so_ops * so_ops = 0;
> -  gdbarch_skip_solib_resolver_ftype *skip_solib_resolver = nullptr;
> -  gdbarch_in_solib_return_trampoline_ftype *in_solib_return_trampoline = nullptr;
> -  gdbarch_in_indirect_branch_thunk_ftype *in_indirect_branch_thunk = nullptr;
> -  gdbarch_stack_frame_destroyed_p_ftype *stack_frame_destroyed_p = nullptr;
> +  gdbarch_skip_solib_resolver_ftype *skip_solib_resolver = generic_skip_solib_resolver;
> +  gdbarch_in_solib_return_trampoline_ftype *in_solib_return_trampoline = generic_in_solib_return_trampoline;
> +  gdbarch_in_indirect_branch_thunk_ftype *in_indirect_branch_thunk = default_in_indirect_branch_thunk;
> +  gdbarch_stack_frame_destroyed_p_ftype *stack_frame_destroyed_p = generic_stack_frame_destroyed_p;
>     gdbarch_elf_make_msymbol_special_ftype *elf_make_msymbol_special = nullptr;
> -  gdbarch_coff_make_msymbol_special_ftype *coff_make_msymbol_special = nullptr;
> -  gdbarch_make_symbol_special_ftype *make_symbol_special = nullptr;
> -  gdbarch_adjust_dwarf2_addr_ftype *adjust_dwarf2_addr = nullptr;
> -  gdbarch_adjust_dwarf2_line_ftype *adjust_dwarf2_line = nullptr;
> +  gdbarch_coff_make_msymbol_special_ftype *coff_make_msymbol_special = default_coff_make_msymbol_special;
> +  gdbarch_make_symbol_special_ftype *make_symbol_special = default_make_symbol_special;
> +  gdbarch_adjust_dwarf2_addr_ftype *adjust_dwarf2_addr = default_adjust_dwarf2_addr;
> +  gdbarch_adjust_dwarf2_line_ftype *adjust_dwarf2_line = default_adjust_dwarf2_line;
>     int cannot_step_breakpoint = 0;
>     int have_nonsteppable_watchpoint = 0;
>     gdbarch_address_class_type_flags_ftype *address_class_type_flags = nullptr;
>     gdbarch_address_class_type_flags_to_name_ftype *address_class_type_flags_to_name = nullptr;
> -  gdbarch_execute_dwarf_cfa_vendor_op_ftype *execute_dwarf_cfa_vendor_op = nullptr;
> +  gdbarch_execute_dwarf_cfa_vendor_op_ftype *execute_dwarf_cfa_vendor_op = default_execute_dwarf_cfa_vendor_op;
>     gdbarch_address_class_name_to_type_flags_ftype *address_class_name_to_type_flags = nullptr;
> -  gdbarch_register_reggroup_p_ftype *register_reggroup_p = nullptr;
> +  gdbarch_register_reggroup_p_ftype *register_reggroup_p = default_register_reggroup_p;
>     gdbarch_fetch_pointer_argument_ftype *fetch_pointer_argument = nullptr;
>     gdbarch_iterate_over_regset_sections_ftype *iterate_over_regset_sections = nullptr;
>     gdbarch_make_corefile_notes_ftype *make_corefile_notes = nullptr;
> @@ -185,16 +185,16 @@ struct gdbarch
>     const char * gcore_bfd_target = 0;
>     int vtable_function_descriptors = 0;
>     int vbit_in_delta = 0;
> -  gdbarch_skip_permanent_breakpoint_ftype *skip_permanent_breakpoint = nullptr;
> +  gdbarch_skip_permanent_breakpoint_ftype *skip_permanent_breakpoint = default_skip_permanent_breakpoint;
>     ULONGEST max_insn_length = 0;
>     gdbarch_displaced_step_copy_insn_ftype *displaced_step_copy_insn = nullptr;
> -  gdbarch_displaced_step_hw_singlestep_ftype *displaced_step_hw_singlestep = nullptr;
> -  gdbarch_displaced_step_fixup_ftype *displaced_step_fixup = nullptr;
> +  gdbarch_displaced_step_hw_singlestep_ftype *displaced_step_hw_singlestep = default_displaced_step_hw_singlestep;
> +  gdbarch_displaced_step_fixup_ftype *displaced_step_fixup = NULL;
>     gdbarch_displaced_step_prepare_ftype *displaced_step_prepare = nullptr;
> -  gdbarch_displaced_step_finish_ftype *displaced_step_finish = nullptr;
> +  gdbarch_displaced_step_finish_ftype *displaced_step_finish = NULL;
>     gdbarch_displaced_step_copy_insn_closure_by_addr_ftype *displaced_step_copy_insn_closure_by_addr = nullptr;
>     gdbarch_displaced_step_restore_all_in_ptid_ftype *displaced_step_restore_all_in_ptid = nullptr;
> -  gdbarch_relocate_instruction_ftype *relocate_instruction = nullptr;
> +  gdbarch_relocate_instruction_ftype *relocate_instruction = NULL;
>     gdbarch_overlay_update_ftype *overlay_update = nullptr;
>     gdbarch_core_read_description_ftype *core_read_description = nullptr;
>     int sofun_address_maybe_missing = 0;
> @@ -224,36 +224,36 @@ struct gdbarch
>     gdbarch_dtrace_disable_probe_ftype *dtrace_disable_probe = nullptr;
>     int has_global_solist = 0;
>     int has_global_breakpoints = 0;
> -  gdbarch_has_shared_address_space_ftype *has_shared_address_space = nullptr;
> -  gdbarch_fast_tracepoint_valid_at_ftype *fast_tracepoint_valid_at = nullptr;
> -  gdbarch_guess_tracepoint_registers_ftype *guess_tracepoint_registers = nullptr;
> -  gdbarch_auto_charset_ftype *auto_charset = nullptr;
> -  gdbarch_auto_wide_charset_ftype *auto_wide_charset = nullptr;
> +  gdbarch_has_shared_address_space_ftype *has_shared_address_space = default_has_shared_address_space;
> +  gdbarch_fast_tracepoint_valid_at_ftype *fast_tracepoint_valid_at = default_fast_tracepoint_valid_at;
> +  gdbarch_guess_tracepoint_registers_ftype *guess_tracepoint_registers = default_guess_tracepoint_registers;
> +  gdbarch_auto_charset_ftype *auto_charset = default_auto_charset;
> +  gdbarch_auto_wide_charset_ftype *auto_wide_charset = default_auto_wide_charset;
>     const char * solib_symbols_extension = 0;
>     int has_dos_based_file_system = 0;
> -  gdbarch_gen_return_address_ftype *gen_return_address = nullptr;
> +  gdbarch_gen_return_address_ftype *gen_return_address = default_gen_return_address;
>     gdbarch_info_proc_ftype *info_proc = nullptr;
>     gdbarch_core_info_proc_ftype *core_info_proc = nullptr;
> -  gdbarch_iterate_over_objfiles_in_search_order_ftype *iterate_over_objfiles_in_search_order = nullptr;
> -  struct ravenscar_arch_ops * ravenscar_ops = 0;
> -  gdbarch_insn_is_call_ftype *insn_is_call = nullptr;
> -  gdbarch_insn_is_ret_ftype *insn_is_ret = nullptr;
> -  gdbarch_insn_is_jump_ftype *insn_is_jump = nullptr;
> -  gdbarch_program_breakpoint_here_p_ftype *program_breakpoint_here_p = nullptr;
> +  gdbarch_iterate_over_objfiles_in_search_order_ftype *iterate_over_objfiles_in_search_order = default_iterate_over_objfiles_in_search_order;
> +  struct ravenscar_arch_ops * ravenscar_ops = NULL;
> +  gdbarch_insn_is_call_ftype *insn_is_call = default_insn_is_call;
> +  gdbarch_insn_is_ret_ftype *insn_is_ret = default_insn_is_ret;
> +  gdbarch_insn_is_jump_ftype *insn_is_jump = default_insn_is_jump;
> +  gdbarch_program_breakpoint_here_p_ftype *program_breakpoint_here_p = default_program_breakpoint_here_p;
>     gdbarch_auxv_parse_ftype *auxv_parse = nullptr;
> -  gdbarch_print_auxv_entry_ftype *print_auxv_entry = nullptr;
> -  gdbarch_vsyscall_range_ftype *vsyscall_range = nullptr;
> -  gdbarch_infcall_mmap_ftype *infcall_mmap = nullptr;
> -  gdbarch_infcall_munmap_ftype *infcall_munmap = nullptr;
> -  gdbarch_gcc_target_options_ftype *gcc_target_options = nullptr;
> -  gdbarch_gnu_triplet_regexp_ftype *gnu_triplet_regexp = nullptr;
> -  gdbarch_addressable_memory_unit_size_ftype *addressable_memory_unit_size = nullptr;
> +  gdbarch_print_auxv_entry_ftype *print_auxv_entry = default_print_auxv_entry;
> +  gdbarch_vsyscall_range_ftype *vsyscall_range = default_vsyscall_range;
> +  gdbarch_infcall_mmap_ftype *infcall_mmap = default_infcall_mmap;
> +  gdbarch_infcall_munmap_ftype *infcall_munmap = default_infcall_munmap;
> +  gdbarch_gcc_target_options_ftype *gcc_target_options = default_gcc_target_options;
> +  gdbarch_gnu_triplet_regexp_ftype *gnu_triplet_regexp = default_gnu_triplet_regexp;
> +  gdbarch_addressable_memory_unit_size_ftype *addressable_memory_unit_size = default_addressable_memory_unit_size;
>     const char * disassembler_options_implicit = 0;
>     char ** disassembler_options = 0;
>     const disasm_options_and_args_t * valid_disassembler_options = 0;
> -  gdbarch_type_align_ftype *type_align = nullptr;
> -  gdbarch_get_pc_address_flags_ftype *get_pc_address_flags = nullptr;
> -  gdbarch_read_core_file_mappings_ftype *read_core_file_mappings = nullptr;
> +  gdbarch_type_align_ftype *type_align = default_type_align;
> +  gdbarch_get_pc_address_flags_ftype *get_pc_address_flags = default_get_pc_address_flags;
> +  gdbarch_read_core_file_mappings_ftype *read_core_file_mappings = default_read_core_file_mappings;
>   };
>   
>   /* Create a new ``struct gdbarch'' based on information provided by
> @@ -275,102 +275,6 @@ gdbarch_alloc (const struct gdbarch_info *info,
>     gdbarch->osabi = info->osabi;
>     gdbarch->target_desc = info->target_desc;
>   
> -  /* Force the explicit initialization of these.  */
> -  gdbarch->short_bit = 2*TARGET_CHAR_BIT;
> -  gdbarch->int_bit = 4*TARGET_CHAR_BIT;
> -  gdbarch->long_bit = 4*TARGET_CHAR_BIT;
> -  gdbarch->long_long_bit = 2*gdbarch->long_bit;
> -  gdbarch->bfloat16_bit = 2*TARGET_CHAR_BIT;
> -  gdbarch->half_bit = 2*TARGET_CHAR_BIT;
> -  gdbarch->float_bit = 4*TARGET_CHAR_BIT;
> -  gdbarch->double_bit = 8*TARGET_CHAR_BIT;
> -  gdbarch->long_double_bit = 8*TARGET_CHAR_BIT;
> -  gdbarch->wchar_bit = 4*TARGET_CHAR_BIT;
> -  gdbarch->wchar_signed = -1;
> -  gdbarch->floatformat_for_type = default_floatformat_for_type;
> -  gdbarch->ptr_bit = gdbarch->int_bit;
> -  gdbarch->char_signed = -1;
> -  gdbarch->virtual_frame_pointer = legacy_virtual_frame_pointer;
> -  gdbarch->num_regs = -1;
> -  gdbarch->sp_regnum = -1;
> -  gdbarch->pc_regnum = -1;
> -  gdbarch->ps_regnum = -1;
> -  gdbarch->fp0_regnum = -1;
> -  gdbarch->stab_reg_to_regnum = no_op_reg_to_regnum;
> -  gdbarch->ecoff_reg_to_regnum = no_op_reg_to_regnum;
> -  gdbarch->sdb_reg_to_regnum = no_op_reg_to_regnum;
> -  gdbarch->dwarf2_reg_to_regnum = no_op_reg_to_regnum;
> -  gdbarch->dummy_id = default_dummy_id;
> -  gdbarch->deprecated_fp_regnum = -1;
> -  gdbarch->call_dummy_location = AT_ENTRY_POINT;
> -  gdbarch->code_of_frame_writable = default_code_of_frame_writable;
> -  gdbarch->print_registers_info = default_print_registers_info;
> -  gdbarch->print_float_info = default_print_float_info;
> -  gdbarch->register_sim_regno = legacy_register_sim_regno;
> -  gdbarch->cannot_fetch_register = cannot_register_not;
> -  gdbarch->cannot_store_register = cannot_register_not;
> -  gdbarch->convert_register_p = generic_convert_register_p;
> -  gdbarch->value_from_register = default_value_from_register;
> -  gdbarch->pointer_to_address = unsigned_pointer_to_address;
> -  gdbarch->address_to_pointer = unsigned_address_to_pointer;
> -  gdbarch->return_in_first_hidden_param_p = default_return_in_first_hidden_param_p;
> -  gdbarch->breakpoint_from_pc = default_breakpoint_from_pc;
> -  gdbarch->sw_breakpoint_from_kind = NULL;
> -  gdbarch->breakpoint_kind_from_current_state = default_breakpoint_kind_from_current_state;
> -  gdbarch->memory_insert_breakpoint = default_memory_insert_breakpoint;
> -  gdbarch->memory_remove_breakpoint = default_memory_remove_breakpoint;
> -  gdbarch->remote_register_number = default_remote_register_number;
> -  gdbarch->unwind_pc = default_unwind_pc;
> -  gdbarch->unwind_sp = default_unwind_sp;
> -  gdbarch->stabs_argument_has_addr = default_stabs_argument_has_addr;
> -  gdbarch->convert_from_func_ptr_addr = convert_from_func_ptr_addr_identity;
> -  gdbarch->addr_bits_remove = core_addr_identity;
> -  gdbarch->memtag_to_string = default_memtag_to_string;
> -  gdbarch->tagged_address_p = default_tagged_address_p;
> -  gdbarch->memtag_matches_p = default_memtag_matches_p;
> -  gdbarch->set_memtags = default_set_memtags;
> -  gdbarch->get_memtag = default_get_memtag;
> -  gdbarch->print_insn = default_print_insn;
> -  gdbarch->skip_trampoline_code = generic_skip_trampoline_code;
> -  gdbarch->skip_solib_resolver = generic_skip_solib_resolver;
> -  gdbarch->in_solib_return_trampoline = generic_in_solib_return_trampoline;
> -  gdbarch->in_indirect_branch_thunk = default_in_indirect_branch_thunk;
> -  gdbarch->stack_frame_destroyed_p = generic_stack_frame_destroyed_p;
> -  gdbarch->coff_make_msymbol_special = default_coff_make_msymbol_special;
> -  gdbarch->make_symbol_special = default_make_symbol_special;
> -  gdbarch->adjust_dwarf2_addr = default_adjust_dwarf2_addr;
> -  gdbarch->adjust_dwarf2_line = default_adjust_dwarf2_line;
> -  gdbarch->execute_dwarf_cfa_vendor_op = default_execute_dwarf_cfa_vendor_op;
> -  gdbarch->register_reggroup_p = default_register_reggroup_p;
> -  gdbarch->skip_permanent_breakpoint = default_skip_permanent_breakpoint;
> -  gdbarch->displaced_step_hw_singlestep = default_displaced_step_hw_singlestep;
> -  gdbarch->displaced_step_fixup = NULL;
> -  gdbarch->displaced_step_finish = NULL;
> -  gdbarch->relocate_instruction = NULL;
> -  gdbarch->has_shared_address_space = default_has_shared_address_space;
> -  gdbarch->fast_tracepoint_valid_at = default_fast_tracepoint_valid_at;
> -  gdbarch->guess_tracepoint_registers = default_guess_tracepoint_registers;
> -  gdbarch->auto_charset = default_auto_charset;
> -  gdbarch->auto_wide_charset = default_auto_wide_charset;
> -  gdbarch->gen_return_address = default_gen_return_address;
> -  gdbarch->iterate_over_objfiles_in_search_order = default_iterate_over_objfiles_in_search_order;
> -  gdbarch->ravenscar_ops = NULL;
> -  gdbarch->insn_is_call = default_insn_is_call;
> -  gdbarch->insn_is_ret = default_insn_is_ret;
> -  gdbarch->insn_is_jump = default_insn_is_jump;
> -  gdbarch->program_breakpoint_here_p = default_program_breakpoint_here_p;
> -  gdbarch->print_auxv_entry = default_print_auxv_entry;
> -  gdbarch->vsyscall_range = default_vsyscall_range;
> -  gdbarch->infcall_mmap = default_infcall_mmap;
> -  gdbarch->infcall_munmap = default_infcall_munmap;
> -  gdbarch->gcc_target_options = default_gcc_target_options;
> -  gdbarch->gnu_triplet_regexp = default_gnu_triplet_regexp;
> -  gdbarch->addressable_memory_unit_size = default_addressable_memory_unit_size;
> -  gdbarch->type_align = default_type_align;
> -  gdbarch->get_pc_address_flags = default_get_pc_address_flags;
> -  gdbarch->read_core_file_mappings = default_read_core_file_mappings;
> -  /* gdbarch_alloc() */
> -
>     return gdbarch;
>   }
>   
> diff --git a/gdb/gdbarch.py b/gdb/gdbarch.py
> index da848feae84..4424b319d5e 100755
> --- a/gdb/gdbarch.py
> +++ b/gdb/gdbarch.py
> @@ -286,11 +286,18 @@ with open("gdbarch.c", "w") as f:
>       print("  void **data = nullptr;", file=f)
>       print(file=f)
>       for c in filter(not_info, components):
> -        if isinstance(c, Value):
> -            print(f"  {c.type} {c.name} = 0;", file=f)
> +        if isinstance(c, Function):
> +            print(f"  gdbarch_{c.name}_ftype *", file=f, end="")
> +        else:
> +            print(f"  {c.type} ", file=f, end="")
> +        print(f"{c.name} = ", file=f, end="")
> +        if c.predefault is not None:
> +            print(f"{c.predefault};", file=f)
> +        elif isinstance(c, Value):
> +            print("0;", file=f)
>           else:
>               assert isinstance(c, Function)
> -            print(f"  gdbarch_{c.name}_ftype *{c.name} = nullptr;", file=f)
> +            print("nullptr;", file=f)
>       print("};", file=f)
>       print(file=f)
>       #
> @@ -312,12 +319,6 @@ with open("gdbarch.c", "w") as f:
>       for c in filter(info, components):
>           print(f"  gdbarch->{c.name} = info->{c.name};", file=f)
>       print(file=f)
> -    print("  /* Force the explicit initialization of these.  */", file=f)
> -    for c in filter(not_info, components):
> -        if c.predefault and c.predefault != "0":
> -            print(f"  gdbarch->{c.name} = {c.predefault};", file=f)
> -    print("  /* gdbarch_alloc() */", file=f)
> -    print(file=f)
>       print("  return gdbarch;", file=f)
>       print("}", file=f)
>       print(file=f)
  

>>>>> "Bruno" == Bruno Larsen <blarsen@redhat.com> writes:

Bruno> On 18/10/2022 18:15, Tom Tromey via Gdb-patches wrote:
>> This changes gdbarch to use the "predefault" to initialize its members
>> inline.  This required changing a couple of the Value instantiations
>> to avoid a use of "gdbarch" during initialization, but on the whole I
>> think this is better -- it removes a hidden ordering dependency.

Bruno> I don't really understand gdbarch, so sorry if this is an obvious
Bruno> question, but why have you only avoided using gdbarch in Value 
Bruno> instantiations and kept them in Info instantiations? (lines 120 and
Bruno> 141, for instance)

This patch only needed to touch the 'predefault's, because after the
patch these are used for inline initializers.

The lines you point out here are 'printer' fields.  These are used for
debug output in the individual methods, so it's still fine for these to
refer to the gdbarch local variable.

Tom