X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=bfd%2Felfxx-target.h;h=d0773e57bcc71d0dedad2ba323ded129f42caf50;hb=80fccad2d4ce82a2ed9a5d8d081eb2daefa09f9d;hp=59da0389172dc24a59bb188f2ea187c06ee0b237;hpb=51b64d56a7c65e6a30649cf9aade57b56c321c0e;p=deliverable%2Fbinutils-gdb.git diff --git a/bfd/elfxx-target.h b/bfd/elfxx-target.h index 59da038917..d0773e57bc 100644 --- a/bfd/elfxx-target.h +++ b/bfd/elfxx-target.h @@ -1,22 +1,22 @@ /* Target definitions for NN-bit ELF - Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001 - Free Software Foundation, Inc. + Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, + 2003, 2004 Free Software Foundation, Inc. -This file is part of BFD, the Binary File Descriptor library. + This file is part of BFD, the Binary File Descriptor library. -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 2 of the License, or -(at your option) any later version. + 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 2 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. + 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, write to the Free Software -Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /* This structure contains everything that BFD knows about a target. It includes things like its byte order, name, what routines to call @@ -32,26 +32,33 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #define bfd_elfNN_get_section_contents _bfd_generic_get_section_contents #endif -#define bfd_elfNN_canonicalize_dynamic_symtab _bfd_elf_canonicalize_dynamic_symtab +#define bfd_elfNN_canonicalize_dynamic_symtab \ + _bfd_elf_canonicalize_dynamic_symtab +#define bfd_elfNN_get_synthetic_symtab \ + _bfd_elf_get_synthetic_symtab +#ifndef bfd_elfNN_canonicalize_reloc #define bfd_elfNN_canonicalize_reloc _bfd_elf_canonicalize_reloc +#endif #ifndef bfd_elfNN_find_nearest_line #define bfd_elfNN_find_nearest_line _bfd_elf_find_nearest_line #endif #define bfd_elfNN_read_minisymbols _bfd_elf_read_minisymbols #define bfd_elfNN_minisymbol_to_symbol _bfd_elf_minisymbol_to_symbol -#define bfd_elfNN_get_dynamic_symtab_upper_bound _bfd_elf_get_dynamic_symtab_upper_bound +#define bfd_elfNN_get_dynamic_symtab_upper_bound \ + _bfd_elf_get_dynamic_symtab_upper_bound #define bfd_elfNN_get_lineno _bfd_elf_get_lineno #ifndef bfd_elfNN_get_reloc_upper_bound #define bfd_elfNN_get_reloc_upper_bound _bfd_elf_get_reloc_upper_bound #endif +#ifndef bfd_elfNN_get_symbol_info #define bfd_elfNN_get_symbol_info _bfd_elf_get_symbol_info -#define bfd_elfNN_get_symtab _bfd_elf_get_symtab -#define bfd_elfNN_get_symtab_upper_bound _bfd_elf_get_symtab_upper_bound -#if 0 /* done in elf-bfd.h */ -#define bfd_elfNN_link_record_dynamic_symbol _bfd_elf_link_record_dynamic_symbol #endif +#define bfd_elfNN_canonicalize_symtab _bfd_elf_canonicalize_symtab +#define bfd_elfNN_get_symtab_upper_bound _bfd_elf_get_symtab_upper_bound #define bfd_elfNN_make_empty_symbol _bfd_elf_make_empty_symbol +#ifndef bfd_elfNN_new_section_hook #define bfd_elfNN_new_section_hook _bfd_elf_new_section_hook +#endif #define bfd_elfNN_set_arch_mach _bfd_elf_set_arch_mach #ifndef bfd_elfNN_set_section_contents #define bfd_elfNN_set_section_contents _bfd_elf_set_section_contents @@ -66,6 +73,9 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef elf_backend_got_symbol_offset #define elf_backend_got_symbol_offset (bfd_vma) 0 #endif +#ifndef elf_backend_can_refcount +#define elf_backend_can_refcount 0 +#endif #ifndef elf_backend_want_got_plt #define elf_backend_want_got_plt 0 #endif @@ -84,15 +94,18 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef elf_backend_want_dynbss #define elf_backend_want_dynbss 1 #endif +#ifndef elf_backend_want_p_paddr_set_to_zero +#define elf_backend_want_p_paddr_set_to_zero 0 +#endif #define bfd_elfNN_bfd_debug_info_start bfd_void #define bfd_elfNN_bfd_debug_info_end bfd_void #define bfd_elfNN_bfd_debug_info_accumulate \ - (void (*) PARAMS ((bfd*, struct sec *))) bfd_void + ((void (*) (bfd*, struct bfd_section *)) bfd_void) #ifndef bfd_elfNN_bfd_get_relocated_section_contents #define bfd_elfNN_bfd_get_relocated_section_contents \ - bfd_generic_get_relocated_section_contents + bfd_generic_get_relocated_section_contents #endif #ifndef bfd_elfNN_bfd_relax_section @@ -115,7 +128,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #define elf_backend_gc_sweep_hook NULL #endif #ifndef bfd_elfNN_bfd_gc_sections -#define bfd_elfNN_bfd_gc_sections _bfd_elfNN_gc_sections +#define bfd_elfNN_bfd_gc_sections bfd_elf_gc_sections #endif #ifndef bfd_elfNN_bfd_merge_sections @@ -123,9 +136,17 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ _bfd_elf_merge_sections #endif +#ifndef bfd_elfNN_bfd_is_group_section +#define bfd_elfNN_bfd_is_group_section bfd_elf_is_group_section +#endif + +#ifndef bfd_elfNN_bfd_discard_group +#define bfd_elfNN_bfd_discard_group bfd_elf_discard_group +#endif + #ifndef bfd_elfNN_bfd_make_debug_symbol #define bfd_elfNN_bfd_make_debug_symbol \ - ((asymbol *(*) PARAMS ((bfd *, void *, unsigned long))) bfd_nullvoidptr) + ((asymbol * (*) (bfd *, void *, unsigned long)) bfd_nullvoidptr) #endif #ifndef bfd_elfNN_bfd_copy_private_symbol_data @@ -137,9 +158,13 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #define bfd_elfNN_bfd_copy_private_section_data \ _bfd_elf_copy_private_section_data #endif +#ifndef bfd_elfNN_bfd_copy_private_header_data +#define bfd_elfNN_bfd_copy_private_header_data \ + _bfd_elf_copy_private_header_data +#endif #ifndef bfd_elfNN_bfd_copy_private_bfd_data #define bfd_elfNN_bfd_copy_private_bfd_data \ - ((boolean (*) PARAMS ((bfd *, bfd *))) bfd_true) + _bfd_elf_copy_private_bfd_data #endif #ifndef bfd_elfNN_bfd_print_private_bfd_data #define bfd_elfNN_bfd_print_private_bfd_data \ @@ -147,11 +172,11 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #endif #ifndef bfd_elfNN_bfd_merge_private_bfd_data #define bfd_elfNN_bfd_merge_private_bfd_data \ - ((boolean (*) PARAMS ((bfd *, bfd *))) bfd_true) + ((bfd_boolean (*) (bfd *, bfd *)) bfd_true) #endif #ifndef bfd_elfNN_bfd_set_private_flags #define bfd_elfNN_bfd_set_private_flags \ - ((boolean (*) PARAMS ((bfd *, flagword))) bfd_true) + ((bfd_boolean (*) (bfd *, flagword)) bfd_true) #endif #ifndef bfd_elfNN_bfd_is_local_label_name #define bfd_elfNN_bfd_is_local_label_name _bfd_elf_is_local_label_name @@ -166,10 +191,20 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ _bfd_elf_canonicalize_dynamic_reloc #endif +#ifndef bfd_elfNN_bfd_link_hash_table_free +#define bfd_elfNN_bfd_link_hash_table_free _bfd_generic_link_hash_table_free +#endif + #ifdef elf_backend_relocate_section #ifndef bfd_elfNN_bfd_link_hash_table_create #define bfd_elfNN_bfd_link_hash_table_create _bfd_elf_link_hash_table_create #endif +#ifndef bfd_elfNN_bfd_link_add_symbols +#define bfd_elfNN_bfd_link_add_symbols bfd_elf_link_add_symbols +#endif +#ifndef bfd_elfNN_bfd_final_link +#define bfd_elfNN_bfd_final_link bfd_elf_final_link +#endif #else /* ! defined (elf_backend_relocate_section) */ /* If no backend relocate_section routine, use the generic linker. Note - this will prevent the port from being able to use some of @@ -187,6 +222,11 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #define bfd_elfNN_bfd_final_link _bfd_generic_final_link #endif #endif /* ! defined (elf_backend_relocate_section) */ + +#ifndef bfd_elfNN_bfd_link_just_syms +#define bfd_elfNN_bfd_link_just_syms _bfd_elf_link_just_syms +#endif + #ifndef bfd_elfNN_bfd_link_split_section #define bfd_elfNN_bfd_link_split_section _bfd_generic_link_split_section #endif @@ -211,6 +251,10 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #define bfd_elfNN_mkarchive _bfd_generic_mkarchive #endif +#ifndef bfd_elfNN_print_symbol +#define bfd_elfNN_print_symbol bfd_elf_print_symbol +#endif + #ifndef elf_symbol_leading_char #define elf_symbol_leading_char 0 #endif @@ -229,10 +273,10 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #endif #ifndef elf_backend_collect -#define elf_backend_collect false +#define elf_backend_collect FALSE #endif #ifndef elf_backend_type_change_ok -#define elf_backend_type_change_ok false +#define elf_backend_type_change_ok FALSE #endif #ifndef elf_backend_sym_is_global @@ -250,6 +294,9 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef elf_backend_get_symbol_type #define elf_backend_get_symbol_type 0 #endif +#ifndef elf_backend_name_local_section_symbols +#define elf_backend_name_local_section_symbols 0 +#endif #ifndef elf_backend_section_processing #define elf_backend_section_processing 0 #endif @@ -313,12 +360,12 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef elf_backend_ecoff_debug_swap #define elf_backend_ecoff_debug_swap 0 #endif +#ifndef elf_backend_bfd_from_remote_memory +#define elf_backend_bfd_from_remote_memory _bfd_elfNN_bfd_from_remote_memory +#endif #ifndef elf_backend_got_header_size #define elf_backend_got_header_size 0 #endif -#ifndef elf_backend_plt_header_size -#define elf_backend_plt_header_size 0 -#endif #ifndef elf_backend_post_process_headers #define elf_backend_post_process_headers NULL #endif @@ -334,6 +381,9 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef elf_backend_hide_symbol #define elf_backend_hide_symbol _bfd_elf_link_hash_hide_symbol #endif +#ifndef elf_backend_merge_symbol_attribute +#define elf_backend_merge_symbol_attribute NULL +#endif #ifndef elf_backend_emit_relocs #define elf_backend_emit_relocs NULL #endif @@ -355,6 +405,30 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef elf_backend_reloc_type_class #define elf_backend_reloc_type_class _bfd_elf_reloc_type_class #endif +#ifndef elf_backend_discard_info +#define elf_backend_discard_info NULL +#endif +#ifndef elf_backend_ignore_discarded_relocs +#define elf_backend_ignore_discarded_relocs NULL +#endif +#ifndef elf_backend_can_make_relative_eh_frame +#define elf_backend_can_make_relative_eh_frame _bfd_elf_can_make_relative +#endif +#ifndef elf_backend_can_make_lsda_relative_eh_frame +#define elf_backend_can_make_lsda_relative_eh_frame _bfd_elf_can_make_relative +#endif +#ifndef elf_backend_encode_eh_address +#define elf_backend_encode_eh_address _bfd_elf_encode_eh_address +#endif +#ifndef elf_backend_write_section +#define elf_backend_write_section NULL +#endif +#ifndef elf_backend_mips_irix_compat +#define elf_backend_mips_irix_compat NULL +#endif +#ifndef elf_backend_mips_rtype_to_howto +#define elf_backend_mips_rtype_to_howto NULL +#endif /* Previously, backends could only use SHT_REL or SHT_RELA relocation sections, but not both. They defined USE_REL to indicate SHT_REL @@ -362,9 +436,6 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ For backwards compatibility, we still support this usage. */ #ifndef USE_REL #define USE_REL 0 -#else -#undef USE_REL -#define USE_REL 1 #endif /* Use these in new code. */ @@ -378,6 +449,17 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #define elf_backend_default_use_rela_p !USE_REL #endif +#ifndef elf_backend_rela_normal +#define elf_backend_rela_normal 0 +#endif + +#ifndef elf_backend_plt_sym_val +#define elf_backend_plt_sym_val NULL +#endif +#ifndef elf_backend_relplt_name +#define elf_backend_relplt_name NULL +#endif + #ifndef ELF_MACHINE_ALT1 #define ELF_MACHINE_ALT1 0 #endif @@ -390,6 +472,10 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #define elf_backend_size_info _bfd_elfNN_size_info #endif +#ifndef elf_backend_special_sections +#define elf_backend_special_sections NULL +#endif + #ifndef elf_backend_sign_extend_vma #define elf_backend_sign_extend_vma 0 #endif @@ -409,6 +495,7 @@ static const struct elf_backend_data elfNN_bed = elf_backend_symbol_processing, elf_backend_symbol_table_processing, elf_backend_get_symbol_type, + elf_backend_name_local_section_symbols, elf_backend_section_processing, elf_backend_section_from_shdr, elf_backend_section_flags, @@ -436,6 +523,7 @@ static const struct elf_backend_data elfNN_bed = elf_backend_output_arch_syms, elf_backend_copy_indirect_symbol, elf_backend_hide_symbol, + elf_backend_merge_symbol_attribute, elf_backend_emit_relocs, elf_backend_count_relocs, elf_backend_grok_prstatus, @@ -443,18 +531,30 @@ static const struct elf_backend_data elfNN_bed = elf_backend_sprintf_vma, elf_backend_fprintf_vma, elf_backend_reloc_type_class, + elf_backend_discard_info, + elf_backend_ignore_discarded_relocs, + elf_backend_can_make_relative_eh_frame, + elf_backend_can_make_lsda_relative_eh_frame, + elf_backend_encode_eh_address, + elf_backend_write_section, + elf_backend_mips_irix_compat, + elf_backend_mips_rtype_to_howto, elf_backend_ecoff_debug_swap, + elf_backend_bfd_from_remote_memory, + elf_backend_plt_sym_val, + elf_backend_relplt_name, ELF_MACHINE_ALT1, ELF_MACHINE_ALT2, &elf_backend_size_info, + elf_backend_special_sections, elf_backend_got_symbol_offset, elf_backend_got_header_size, - elf_backend_plt_header_size, elf_backend_collect, elf_backend_type_change_ok, elf_backend_may_use_rel_p, elf_backend_may_use_rela_p, elf_backend_default_use_rela_p, + elf_backend_rela_normal, elf_backend_sign_extend_vma, elf_backend_want_got_plt, elf_backend_plt_readonly, @@ -463,8 +563,9 @@ static const struct elf_backend_data elfNN_bed = elf_backend_plt_alignment, elf_backend_can_gc_sections, elf_backend_can_refcount, + elf_backend_want_got_sym, elf_backend_want_dynbss, - elf_backend_want_got_sym + elf_backend_want_p_paddr_set_to_zero }; #endif @@ -495,7 +596,7 @@ const bfd_target TARGET_BIG_SYM = /* section_flags: mask of all section flags */ (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC | SEC_READONLY | SEC_CODE | SEC_DATA | SEC_DEBUGGING | SEC_EXCLUDE | SEC_SORT_ENTRIES - | SEC_ARCH_BIT_0 | SEC_SMALL_DATA | SEC_MERGE | SEC_STRINGS), + | SEC_ARCH_BIT_0 | SEC_SMALL_DATA | SEC_MERGE | SEC_STRINGS | SEC_GROUP), /* leading_symbol_char: is the first char of a user symbol predictable, and if so what is it */ @@ -508,9 +609,9 @@ const bfd_target TARGET_BIG_SYM = /* ar_max_namelen: maximum number of characters in an archive header FIXME: this really has nothing to do with ELF, this is a characteristic - of the archiver and should be independently tunable. This value is - a WAG (wild a** guess) */ - 14, + of the archiver and should be independently tunable. The System V ABI, + Chapter 7 (Formats & Protocols), Archive section sets this as 15. */ + 15, /* Routines to byte-swap various sized integers from the data sections */ bfd_getb64, bfd_getb_signed_64, bfd_putb64, @@ -543,19 +644,19 @@ const bfd_target TARGET_BIG_SYM = bfd_elfNN_write_corefile_contents, }, - BFD_JUMP_TABLE_GENERIC (bfd_elfNN), - BFD_JUMP_TABLE_COPY (bfd_elfNN), - BFD_JUMP_TABLE_CORE (bfd_elfNN), + BFD_JUMP_TABLE_GENERIC (bfd_elfNN), + BFD_JUMP_TABLE_COPY (bfd_elfNN), + BFD_JUMP_TABLE_CORE (bfd_elfNN), #ifdef bfd_elfNN_archive_functions - BFD_JUMP_TABLE_ARCHIVE (bfd_elfNN_archive), + BFD_JUMP_TABLE_ARCHIVE (bfd_elfNN_archive), #else - BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff), + BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff), #endif - BFD_JUMP_TABLE_SYMBOLS (bfd_elfNN), - BFD_JUMP_TABLE_RELOCS (bfd_elfNN), - BFD_JUMP_TABLE_WRITE (bfd_elfNN), - BFD_JUMP_TABLE_LINK (bfd_elfNN), - BFD_JUMP_TABLE_DYNAMIC (bfd_elfNN), + BFD_JUMP_TABLE_SYMBOLS (bfd_elfNN), + BFD_JUMP_TABLE_RELOCS (bfd_elfNN), + BFD_JUMP_TABLE_WRITE (bfd_elfNN), + BFD_JUMP_TABLE_LINK (bfd_elfNN), + BFD_JUMP_TABLE_DYNAMIC (bfd_elfNN), /* Alternative endian target. */ #ifdef TARGET_LITTLE_SYM @@ -565,7 +666,7 @@ const bfd_target TARGET_BIG_SYM = #endif /* backend_data: */ - (PTR) &elfNN_bed + &elfNN_bed }; #endif @@ -591,7 +692,7 @@ const bfd_target TARGET_LITTLE_SYM = /* section_flags: mask of all section flags */ (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC | SEC_READONLY | SEC_CODE | SEC_DATA | SEC_DEBUGGING | SEC_EXCLUDE | SEC_SORT_ENTRIES - | SEC_ARCH_BIT_0 | SEC_SMALL_DATA | SEC_MERGE | SEC_STRINGS), + | SEC_ARCH_BIT_0 | SEC_SMALL_DATA | SEC_MERGE | SEC_STRINGS | SEC_GROUP), /* leading_symbol_char: is the first char of a user symbol predictable, and if so what is it */ @@ -604,9 +705,9 @@ const bfd_target TARGET_LITTLE_SYM = /* ar_max_namelen: maximum number of characters in an archive header FIXME: this really has nothing to do with ELF, this is a characteristic - of the archiver and should be independently tunable. This value is - a WAG (wild a** guess) */ - 14, + of the archiver and should be independently tunable. The System V ABI, + Chapter 7 (Formats & Protocols), Archive section sets this as 15. */ + 15, /* Routines to byte-swap various sized integers from the data sections */ bfd_getl64, bfd_getl_signed_64, bfd_putl64, @@ -639,19 +740,19 @@ const bfd_target TARGET_LITTLE_SYM = bfd_elfNN_write_corefile_contents, }, - BFD_JUMP_TABLE_GENERIC (bfd_elfNN), - BFD_JUMP_TABLE_COPY (bfd_elfNN), - BFD_JUMP_TABLE_CORE (bfd_elfNN), + BFD_JUMP_TABLE_GENERIC (bfd_elfNN), + BFD_JUMP_TABLE_COPY (bfd_elfNN), + BFD_JUMP_TABLE_CORE (bfd_elfNN), #ifdef bfd_elfNN_archive_functions - BFD_JUMP_TABLE_ARCHIVE (bfd_elfNN_archive), + BFD_JUMP_TABLE_ARCHIVE (bfd_elfNN_archive), #else - BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff), + BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff), #endif - BFD_JUMP_TABLE_SYMBOLS (bfd_elfNN), - BFD_JUMP_TABLE_RELOCS (bfd_elfNN), - BFD_JUMP_TABLE_WRITE (bfd_elfNN), - BFD_JUMP_TABLE_LINK (bfd_elfNN), - BFD_JUMP_TABLE_DYNAMIC (bfd_elfNN), + BFD_JUMP_TABLE_SYMBOLS (bfd_elfNN), + BFD_JUMP_TABLE_RELOCS (bfd_elfNN), + BFD_JUMP_TABLE_WRITE (bfd_elfNN), + BFD_JUMP_TABLE_LINK (bfd_elfNN), + BFD_JUMP_TABLE_DYNAMIC (bfd_elfNN), /* Alternative endian target. */ #ifdef TARGET_BIG_SYM @@ -661,6 +762,6 @@ const bfd_target TARGET_LITTLE_SYM = #endif /* backend_data: */ - (PTR) &elfNN_bed + &elfNN_bed }; #endif