1 /* CGEN generic disassembler support code. 2 Copyright (C) 1996-2018 Free Software Foundation, Inc. 3 4 This file is part of libopcodes. 5 6 This library is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 It is distributed in the hope that it will be useful, but WITHOUT 12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public 14 License for more details. 15 16 You should have received a copy of the GNU General Public License along 17 with this program; if not, write to the Free Software Foundation, Inc., 18 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ 19 20 #include "sysdep.h" 21 #include <stdio.h> 22 #include "ansidecl.h" 23 #include "libiberty.h" 24 #include "bfd.h" 25 #include "symcat.h" 26 #include "opcode/cgen.h" 27 28 static CGEN_INSN_LIST * hash_insn_array (CGEN_CPU_DESC, const CGEN_INSN *, int, int, CGEN_INSN_LIST **, CGEN_INSN_LIST *); 29 static CGEN_INSN_LIST * hash_insn_list (CGEN_CPU_DESC, const CGEN_INSN_LIST *, CGEN_INSN_LIST **, CGEN_INSN_LIST *); 30 static void build_dis_hash_table (CGEN_CPU_DESC); 31 static int count_decodable_bits (const CGEN_INSN *); 32 static void add_insn_to_hash_chain (CGEN_INSN_LIST *, 33 const CGEN_INSN *, 34 CGEN_INSN_LIST **, 35 unsigned int); 36 37 /* Return the number of decodable bits in this insn. */ 38 static int 39 count_decodable_bits (const CGEN_INSN *insn) 40 { 41 unsigned mask = CGEN_INSN_BASE_MASK (insn); 42 int bits = 0; 43 unsigned m; 44 45 for (m = 1; m != 0; m <<= 1) 46 { 47 if (mask & m) 48 ++bits; 49 } 50 return bits; 51 } 52 53 /* Add an instruction to the hash chain. */ 54 static void 55 add_insn_to_hash_chain (CGEN_INSN_LIST *hentbuf, 56 const CGEN_INSN *insn, 57 CGEN_INSN_LIST **htable, 58 unsigned int hash) 59 { 60 CGEN_INSN_LIST *current_buf; 61 CGEN_INSN_LIST *previous_buf; 62 int insn_decodable_bits; 63 64 /* Add insns sorted by the number of decodable bits, in decreasing order. 65 This ensures that any insn which is a special case of another will be 66 checked first. */ 67 insn_decodable_bits = count_decodable_bits (insn); 68 previous_buf = NULL; 69 for (current_buf = htable[hash]; current_buf != NULL; 70 current_buf = current_buf->next) 71 { 72 int current_decodable_bits = count_decodable_bits (current_buf->insn); 73 if (insn_decodable_bits >= current_decodable_bits) 74 break; 75 previous_buf = current_buf; 76 } 77 78 /* Now insert the new insn. */ 79 hentbuf->insn = insn; 80 hentbuf->next = current_buf; 81 if (previous_buf == NULL) 82 htable[hash] = hentbuf; 83 else 84 previous_buf->next = hentbuf; 85 } 86 87 /* Subroutine of build_dis_hash_table to add INSNS to the hash table. 88 89 COUNT is the number of elements in INSNS. 90 ENTSIZE is sizeof (CGEN_IBASE) for the target. 91 ??? No longer used but leave in for now. 92 HTABLE points to the hash table. 93 HENTBUF is a pointer to sufficiently large buffer of hash entries. 94 The result is a pointer to the next entry to use. 95 96 The table is scanned backwards as additions are made to the front of the 97 list and we want earlier ones to be prefered. */ 98 99 static CGEN_INSN_LIST * 100 hash_insn_array (CGEN_CPU_DESC cd, 101 const CGEN_INSN * insns, 102 int count, 103 int entsize ATTRIBUTE_UNUSED, 104 CGEN_INSN_LIST ** htable, 105 CGEN_INSN_LIST * hentbuf) 106 { 107 int big_p = CGEN_CPU_INSN_ENDIAN (cd) == CGEN_ENDIAN_BIG; 108 int i; 109 110 for (i = count - 1; i >= 0; --i, ++hentbuf) 111 { 112 unsigned int hash; 113 char buf [4]; 114 unsigned long value; 115 const CGEN_INSN *insn = &insns[i]; 116 117 if (! (* cd->dis_hash_p) (insn)) 118 continue; 119 120 /* We don't know whether the target uses the buffer or the base insn 121 to hash on, so set both up. */ 122 123 value = CGEN_INSN_BASE_VALUE (insn); 124 bfd_put_bits ((bfd_vma) value, 125 buf, 126 CGEN_INSN_MASK_BITSIZE (insn), 127 big_p); 128 hash = (* cd->dis_hash) (buf, value); 129 add_insn_to_hash_chain (hentbuf, insn, htable, hash); 130 } 131 132 return hentbuf; 133 } 134 135 /* Subroutine of build_dis_hash_table to add INSNS to the hash table. 136 This function is identical to hash_insn_array except the insns are 137 in a list. */ 138 139 static CGEN_INSN_LIST * 140 hash_insn_list (CGEN_CPU_DESC cd, 141 const CGEN_INSN_LIST *insns, 142 CGEN_INSN_LIST **htable, 143 CGEN_INSN_LIST *hentbuf) 144 { 145 int big_p = CGEN_CPU_INSN_ENDIAN (cd) == CGEN_ENDIAN_BIG; 146 const CGEN_INSN_LIST *ilist; 147 148 for (ilist = insns; ilist != NULL; ilist = ilist->next, ++ hentbuf) 149 { 150 unsigned int hash; 151 char buf[4]; 152 unsigned long value; 153 154 if (! (* cd->dis_hash_p) (ilist->insn)) 155 continue; 156 157 /* We don't know whether the target uses the buffer or the base insn 158 to hash on, so set both up. */ 159 160 value = CGEN_INSN_BASE_VALUE (ilist->insn); 161 bfd_put_bits((bfd_vma) value, 162 buf, 163 CGEN_INSN_MASK_BITSIZE (ilist->insn), 164 big_p); 165 hash = (* cd->dis_hash) (buf, value); 166 add_insn_to_hash_chain (hentbuf, ilist->insn, htable, hash); 167 } 168 169 return hentbuf; 170 } 171 172 /* Build the disassembler instruction hash table. */ 173 174 static void 175 build_dis_hash_table (CGEN_CPU_DESC cd) 176 { 177 int count = cgen_insn_count (cd) + cgen_macro_insn_count (cd); 178 CGEN_INSN_TABLE *insn_table = & cd->insn_table; 179 CGEN_INSN_TABLE *macro_insn_table = & cd->macro_insn_table; 180 unsigned int hash_size = cd->dis_hash_size; 181 CGEN_INSN_LIST *hash_entry_buf; 182 CGEN_INSN_LIST **dis_hash_table; 183 CGEN_INSN_LIST *dis_hash_table_entries; 184 185 /* The space allocated for the hash table consists of two parts: 186 the hash table and the hash lists. */ 187 188 dis_hash_table = (CGEN_INSN_LIST **) 189 xmalloc (hash_size * sizeof (CGEN_INSN_LIST *)); 190 memset (dis_hash_table, 0, hash_size * sizeof (CGEN_INSN_LIST *)); 191 dis_hash_table_entries = hash_entry_buf = (CGEN_INSN_LIST *) 192 xmalloc (count * sizeof (CGEN_INSN_LIST)); 193 194 /* Add compiled in insns. 195 Don't include the first one as it is a reserved entry. */ 196 /* ??? It was the end of all hash chains, and also the special 197 "invalid insn" marker. May be able to do it differently now. */ 198 199 hash_entry_buf = hash_insn_array (cd, 200 insn_table->init_entries + 1, 201 insn_table->num_init_entries - 1, 202 insn_table->entry_size, 203 dis_hash_table, hash_entry_buf); 204 205 /* Add compiled in macro-insns. */ 206 207 hash_entry_buf = hash_insn_array (cd, macro_insn_table->init_entries, 208 macro_insn_table->num_init_entries, 209 macro_insn_table->entry_size, 210 dis_hash_table, hash_entry_buf); 211 212 /* Add runtime added insns. 213 Later added insns will be prefered over earlier ones. */ 214 215 hash_entry_buf = hash_insn_list (cd, insn_table->new_entries, 216 dis_hash_table, hash_entry_buf); 217 218 /* Add runtime added macro-insns. */ 219 220 hash_insn_list (cd, macro_insn_table->new_entries, 221 dis_hash_table, hash_entry_buf); 222 223 cd->dis_hash_table = dis_hash_table; 224 cd->dis_hash_table_entries = dis_hash_table_entries; 225 } 226 227 /* Return the first entry in the hash list for INSN. */ 228 229 CGEN_INSN_LIST * 230 cgen_dis_lookup_insn (CGEN_CPU_DESC cd, const char * buf, CGEN_INSN_INT value) 231 { 232 unsigned int hash; 233 234 if (cd->dis_hash_table == NULL) 235 build_dis_hash_table (cd); 236 237 hash = (* cd->dis_hash) (buf, value); 238 239 return cd->dis_hash_table[hash]; 240 } 241