gcc/java/constants.c

   1 /* Handle the constant pool of the Java(TM) Virtual Machine.
   2    Copyright (C) 1997, 1998, 1999, 2000, 2001, 2003 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC 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 2, or (at your option)
   9 any later version.
  10
  11 GCC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15 You should have received a copy of the GNU General Public License
  16 along with GCC; see the file COPYING.  If not, write to
  17 the Free Software Foundation, 59 Temple Place - Suite 330,
  18 Boston, MA 02111-1307, USA.
  19
  20 Java and all Java-based marks are trademarks or registered trademarks
  21 of Sun Microsystems, Inc. in the United States and other countries.
  22 The Free Software Foundation is independent of Sun Microsystems, Inc.  */
  23
  24 #include "config.h"
  25 #include "system.h"
  26 #include "coretypes.h"
  27 #include "tm.h"
  28 #include "jcf.h"
  29 #include "tree.h"
  30 #include "java-tree.h"
  31 #include "toplev.h"
  32 #include "ggc.h"
  33
  34 static void set_constant_entry (CPool *, int, int, jword);
  35 static int find_tree_constant (CPool *, int, tree);
  36 static int find_class_or_string_constant (CPool *, int, tree);
  37 static int find_name_and_type_constant (CPool *, tree, tree);
  38 static tree get_tag_node (int);
  39 static tree build_constant_data_ref (void);
  40
  41 /* Set the INDEX'th constant in CPOOL to have the given TAG and VALUE. */
  42
  43 static void
  44 set_constant_entry (CPool *cpool, int index, int tag, jword value)
  45 {
  46   if (cpool->data == NULL)
  47     {
  48       cpool->capacity = 100;
  49       cpool->tags = ggc_alloc_cleared (sizeof(uint8) * cpool->capacity);
  50       cpool->data = ggc_alloc_cleared (sizeof(union cpool_entry)
  51                                        * cpool->capacity);
  52       cpool->count = 1;
  53     }
  54   if (index >= cpool->capacity)
  55     {
  56       int old_cap = cpool->capacity;
  57       cpool->capacity *= 2;
  58       if (index >= cpool->capacity)
  59         cpool->capacity = index + 10;
  60       cpool->tags = ggc_realloc (cpool->tags,
  61                                  sizeof(uint8) * cpool->capacity);
  62       cpool->data = ggc_realloc (cpool->data,
  63                                  sizeof(union cpool_entry) * cpool->capacity);
  64
  65       /* Make sure GC never sees uninitialized tag values.  */
  66       memset (cpool->tags + old_cap, 0, cpool->capacity - old_cap);
  67       memset (cpool->data + old_cap, 0,
  68               (cpool->capacity - old_cap) * sizeof (union cpool_entry));
  69     }
  70   if (index >= cpool->count)
  71     cpool->count = index + 1;
  72   cpool->tags[index] = tag;
  73   cpool->data[index].w = value;
  74 }
  75
  76 /* Find (or create) a constant pool entry matching TAG and VALUE. */
  77
  78 int
  79 find_constant1 (CPool *cpool, int tag, jword value)
  80 {
  81   int i;
  82   for (i = cpool->count;  --i > 0; )
  83     {
  84       if (cpool->tags[i] == tag && cpool->data[i].w == value)
  85         return i;
  86     }
  87   i = cpool->count == 0 ? 1 : cpool->count;
  88   set_constant_entry (cpool, i, tag, value);
  89   return i;
  90 }
  91
  92 /* Find a double-word constant pool entry matching TAG and WORD1/WORD2. */
  93
  94 int
  95 find_constant2 (CPool *cpool, int tag, jword word1, jword word2)
  96 {
  97   int i;
  98   for (i = cpool->count - 1;  --i > 0; )
  99     {
 100       if (cpool->tags[i] == tag
 101           && cpool->data[i].w == word1
 102           && cpool->data[i+1].w == word2)
 103         return i;
 104     }
 105   i = cpool->count == 0 ? 1 : cpool->count;
 106   set_constant_entry (cpool, i, tag, word1);
 107   set_constant_entry (cpool, i+1, 0, word2);
 108   return i;
 109 }
 110
 111 static int
 112 find_tree_constant (CPool *cpool, int tag, tree value)
 113 {
 114   int i;
 115   for (i = cpool->count;  --i > 0; )
 116     {
 117       if (cpool->tags[i] == tag && cpool->data[i].t == value)
 118         return i;
 119     }
 120   i = cpool->count == 0 ? 1 : cpool->count;
 121   set_constant_entry (cpool, i, tag, 0);
 122   cpool->data[i].t = value;
 123   return i;
 124 }
 125
 126
 127 int
 128 find_utf8_constant (CPool *cpool, tree name)
 129 {
 130   if (name == NULL_TREE)
 131     return 0;
 132   return find_tree_constant (cpool, CONSTANT_Utf8, name);
 133 }
 134
 135 static int
 136 find_class_or_string_constant (CPool *cpool, int tag, tree name)
 137 {
 138   jword j = find_utf8_constant (cpool, name);
 139   int i;
 140   for (i = cpool->count;  --i > 0; )
 141     {
 142       if (cpool->tags[i] == tag && cpool->data[i].w == j)
 143         return i;
 144     }
 145   i = cpool->count;
 146   set_constant_entry (cpool, i, tag, j);
 147   return i;
 148 }
 149
 150 int
 151 find_class_constant (CPool *cpool, tree type)
 152 {
 153   return find_class_or_string_constant (cpool, CONSTANT_Class,
 154                                         build_internal_class_name (type));
 155 }
 156
 157 /* Allocate a CONSTANT_string entry given a STRING_CST. */
 158
 159 int
 160 find_string_constant (CPool *cpool, tree string)
 161 {
 162   string = get_identifier (TREE_STRING_POINTER (string));
 163   return find_class_or_string_constant (cpool, CONSTANT_String, string);
 164
 165 }
 166
 167 /* Find (or create) a CONSTANT_NameAndType matching NAME and TYPE.
 168    Return its index in the constant pool CPOOL. */
 169
 170 static int
 171 find_name_and_type_constant (CPool *cpool, tree name, tree type)
 172 {
 173   int name_index = find_utf8_constant (cpool, name);
 174   int type_index = find_utf8_constant (cpool, build_java_signature (type));
 175   return find_constant1 (cpool, CONSTANT_NameAndType,
 176                          (name_index << 16) | type_index);
 177 }
 178
 179 /* Find (or create) a CONSTANT_Fieldref for DECL (a FIELD_DECL or VAR_DECL).
 180    Return its index in the constant pool CPOOL. */
 181
 182 int
 183 find_fieldref_index (CPool *cpool, tree decl)
 184 {
 185   int class_index = find_class_constant (cpool, DECL_CONTEXT (decl));
 186   int name_type_index
 187     = find_name_and_type_constant (cpool, DECL_NAME (decl), TREE_TYPE (decl));
 188   return find_constant1 (cpool, CONSTANT_Fieldref,
 189                          (class_index << 16) | name_type_index);
 190 }
 191
 192 /* Find (or create) a CONSTANT_Methodref for DECL (a FUNCTION_DECL).
 193    Return its index in the constant pool CPOOL. */
 194
 195 int
 196 find_methodref_index (CPool *cpool, tree decl)
 197 {
 198   return find_methodref_with_class_index (cpool, decl, DECL_CONTEXT (decl));
 199 }
 200
 201 int
 202 find_methodref_with_class_index (CPool *cpool, tree decl, tree mclass)
 203 {
 204   int class_index = find_class_constant (cpool, mclass);
 205   tree name = DECL_CONSTRUCTOR_P (decl) ? init_identifier_node
 206     : DECL_NAME (decl);
 207   int name_type_index;
 208   name_type_index =
 209       find_name_and_type_constant (cpool, name, TREE_TYPE (decl));
 210   return find_constant1 (cpool,
 211                          CLASS_INTERFACE (TYPE_NAME (mclass))
 212                          ? CONSTANT_InterfaceMethodref
 213                          : CONSTANT_Methodref,
 214                          (class_index << 16) | name_type_index);
 215 }
 216
 217 #define PUT1(X)  (*ptr++ = (X))
 218 #define PUT2(X)  (PUT1((X) >> 8), PUT1(X))
 219 #define PUT4(X)  (PUT2((X) >> 16), PUT2(X))
 220 #define PUTN(P, N)  (memcpy(ptr, (P), (N)), ptr += (N))
 221
 222 /* Give the number of bytes needed in a .class file for the CPOOL
 223    constant pool.  Includes the 2-byte constant_pool_count. */
 224
 225 int
 226 count_constant_pool_bytes (CPool *cpool)
 227 {
 228   int size = 2;
 229   int i = 1;
 230   for ( ;  i < cpool->count;  i++)
 231     {
 232       size++;
 233       switch (cpool->tags[i])
 234         {
 235         case CONSTANT_NameAndType:
 236         case CONSTANT_Fieldref:
 237         case CONSTANT_Methodref:
 238         case CONSTANT_InterfaceMethodref:
 239         case CONSTANT_Float:
 240         case CONSTANT_Integer:
 241           size += 4;
 242           break;
 243         case CONSTANT_Class:
 244         case CONSTANT_String:
 245           size += 2;
 246           break;
 247         case CONSTANT_Long:
 248         case CONSTANT_Double:
 249           size += 8;
 250           i++;
 251           break;
 252         case CONSTANT_Utf8:
 253           {
 254             tree t = cpool->data[i].t;
 255             int len = IDENTIFIER_LENGTH (t);
 256             size += len + 2;
 257           }
 258           break;
 259         default:
 260           /* Second word of CONSTANT_Long and  CONSTANT_Double. */
 261           size--;
 262         }
 263     }
 264   return size;
 265 }
 266
 267 /* Write the constant pool CPOOL into BUFFER.
 268    The length of BUFFER is LENGTH, which must match the needed length. */
 269
 270 void
 271 write_constant_pool (CPool *cpool, unsigned char *buffer, int length)
 272 {
 273   unsigned char *ptr = buffer;
 274   int i = 1;
 275   union cpool_entry *datap = &cpool->data[1];
 276   PUT2 (cpool->count);
 277   for ( ;  i < cpool->count;  i++, datap++)
 278     {
 279       int tag = cpool->tags[i];
 280       PUT1 (tag);
 281       switch (tag)
 282         {
 283         case CONSTANT_NameAndType:
 284         case CONSTANT_Fieldref:
 285         case CONSTANT_Methodref:
 286         case CONSTANT_InterfaceMethodref:
 287         case CONSTANT_Float:
 288         case CONSTANT_Integer:
 289           PUT4 (datap->w);
 290           break;
 291         case CONSTANT_Class:
 292         case CONSTANT_String:
 293           PUT2 (datap->w);
 294           break;
 295           break;
 296         case CONSTANT_Long:
 297         case CONSTANT_Double:
 298           PUT4(datap->w);
 299           i++;
 300           datap++;
 301           PUT4 (datap->w);
 302           break;
 303         case CONSTANT_Utf8:
 304           {
 305             tree t = datap->t;
 306             int len = IDENTIFIER_LENGTH (t);
 307             PUT2 (len);
 308             PUTN (IDENTIFIER_POINTER (t), len);
 309           }
 310           break;
 311         }
 312     }
 313
 314   if (ptr != buffer + length)
 315     abort ();
 316 }
 317
 318 CPool *outgoing_cpool;
 319
 320 static GTY(()) tree tag_nodes[13];
 321 static tree
 322 get_tag_node (int tag)
 323 {
 324   /* A Cache for build_int_2 (CONSTANT_XXX, 0). */
 325
 326   if (tag_nodes[tag] == NULL_TREE)
 327     tag_nodes[tag] = build_int_2 (tag, 0);
 328   return tag_nodes[tag];
 329 }
 330
 331 /* Look for a constant pool entry that matches TAG and NAME.
 332    Creates a new entry if not found.
 333    TAG is one of CONSTANT_Utf8, CONSTANT_String or CONSTANT_Class.
 334    NAME is an IDENTIFIER_NODE naming the Utf8 constant, string, or class.
 335    Returns the index of the entry. */
 336
 337 int
 338 alloc_name_constant (int tag, tree name)
 339 {
 340   return find_tree_constant (outgoing_cpool, tag, name);
 341 }
 342
 343 /* Build an identifier for the internal name of reference type TYPE. */
 344
 345 tree
 346 build_internal_class_name (tree type)
 347 {
 348   tree name;
 349   if (TYPE_ARRAY_P (type))
 350     name = build_java_signature (type);
 351   else
 352     {
 353       name = TYPE_NAME (type);
 354       if (TREE_CODE (name) != IDENTIFIER_NODE)
 355         name = DECL_NAME (name);
 356       name = identifier_subst (name, "", '.', '/', "");
 357     }
 358   return name;
 359 }
 360
 361 /* Look for a CONSTANT_Class entry for CLAS, creating a new one if needed. */
 362
 363 int
 364 alloc_class_constant (tree clas)
 365 {
 366   tree class_name = build_internal_class_name (clas);
 367
 368   return alloc_name_constant (CONSTANT_Class,
 369                               (unmangle_classname
 370                                (IDENTIFIER_POINTER(class_name),
 371                                 IDENTIFIER_LENGTH(class_name))));
 372 }
 373
 374 /* Return a reference to the data array of the current constant pool. */
 375
 376 static tree
 377 build_constant_data_ref (void)
 378 {
 379   tree cpool_data_ref = NULL_TREE;
 380
 381   if (TYPE_CPOOL_DATA_REF (current_class))
 382     cpool_data_ref = TYPE_CPOOL_DATA_REF (current_class);
 383
 384   if (cpool_data_ref == NULL_TREE)
 385     {
 386       tree decl;
 387       tree decl_name = mangled_classname ("_CD_", current_class);
 388       decl = build_decl (VAR_DECL, decl_name,
 389                          build_array_type (ptr_type_node,
 390                                            one_elt_array_domain_type));
 391       TREE_STATIC (decl) = 1;
 392       make_decl_rtl (decl, NULL);
 393       TYPE_CPOOL_DATA_REF (current_class) = cpool_data_ref
 394         = build1 (ADDR_EXPR, ptr_type_node, decl);
 395     }
 396   return cpool_data_ref;
 397 }
 398
 399 /* Get the pointer value at the INDEX'th element of the constant pool. */
 400
 401 tree
 402 build_ref_from_constant_pool (int index)
 403 {
 404   tree t = build_constant_data_ref ();
 405   index *= int_size_in_bytes (ptr_type_node);
 406   t = fold (build (PLUS_EXPR, ptr_type_node,
 407                               t, build_int_2 (index, 0)));
 408   return build1 (INDIRECT_REF, ptr_type_node, t);
 409 }
 410
 411 /* Build an initializer for the constants field of the current constant pool.
 412    Should only be called at top-level, since it may emit declarations. */
 413
 414 tree
 415 build_constants_constructor (void)
 416 {
 417   tree tags_value, data_value;
 418   tree cons;
 419   tree tags_list = NULL_TREE;
 420   tree data_list = NULL_TREE;
 421   int i;
 422   for (i = outgoing_cpool->count;  --i > 0; )
 423     {
 424       tags_list
 425         = tree_cons (NULL_TREE, get_tag_node (outgoing_cpool->tags[i]),
 426                      tags_list);
 427       data_list
 428         = tree_cons (NULL_TREE, build_utf8_ref (outgoing_cpool->data[i].t),
 429                      data_list);
 430     }
 431   if (outgoing_cpool->count > 0)
 432     {
 433       tree index_type;
 434       tree data_decl, tags_decl, tags_type;
 435       tree max_index = build_int_2 (outgoing_cpool->count - 1, 0);
 436       TREE_TYPE (max_index) = sizetype;
 437       index_type = build_index_type (max_index);
 438
 439       /* Add dummy 0'th element of constant pool. */
 440       tags_list = tree_cons (NULL_TREE, get_tag_node (0), tags_list);
 441       data_list = tree_cons (NULL_TREE, null_pointer_node, data_list);
 442
 443       data_decl = TREE_OPERAND (build_constant_data_ref (), 0);
 444       TREE_TYPE (data_decl) = build_array_type (ptr_type_node, index_type),
 445       DECL_INITIAL (data_decl) = build (CONSTRUCTOR, TREE_TYPE (data_decl),
 446                                         NULL_TREE, data_list);
 447       DECL_SIZE (data_decl) = TYPE_SIZE (TREE_TYPE (data_decl));
 448       DECL_SIZE_UNIT (data_decl) = TYPE_SIZE_UNIT (TREE_TYPE (data_decl));
 449       rest_of_decl_compilation (data_decl, (char *) 0, 1, 0);
 450       data_value = build_address_of (data_decl);
 451
 452       tags_type = build_array_type (unsigned_byte_type_node, index_type);
 453       tags_decl = build_decl (VAR_DECL, mangled_classname ("_CT_",
 454                                                            current_class),
 455                               tags_type);
 456       TREE_STATIC (tags_decl) = 1;
 457       DECL_INITIAL (tags_decl) = build (CONSTRUCTOR, tags_type,
 458                                         NULL_TREE, tags_list);
 459       rest_of_decl_compilation (tags_decl, (char*) 0, 1, 0);
 460       tags_value = build_address_of (tags_decl);
 461     }
 462   else
 463     {
 464       data_value = null_pointer_node;
 465       tags_value = null_pointer_node;
 466     }
 467   START_RECORD_CONSTRUCTOR (cons, constants_type_node);
 468   PUSH_FIELD_VALUE (cons, "size", build_int_2 (outgoing_cpool->count, 0));
 469   PUSH_FIELD_VALUE (cons, "tags", tags_value);
 470   PUSH_FIELD_VALUE (cons, "data", data_value);
 471   FINISH_RECORD_CONSTRUCTOR (cons);
 472   return cons;
 473 }
 474
 475 #include "gt-java-constants.h"