nsz Git - libfirm/blob - ir/be/begnuas.c

   1 /*
   2  * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   6  * This file may be distributed and/or modified under the terms of the
   7  * GNU General Public License version 2 as published by the Free Software
   8  * Foundation and appearing in the file LICENSE.GPL included in the
   9  * packaging of this file.
  10  *
  11  * Licensees holding valid libFirm Professional Edition licenses may use
  12  * this file in accordance with the libFirm Commercial License.
  13  * Agreement provided with the Software.
  14  *
  15  * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
  16  * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief       Dumps global variables and constants as gas assembler.
  23  * @author      Christian Wuerdig, Matthias Braun
  24  * @date        04.11.2005
  25  * @version     $Id$
  26  */
  27 #include "config.h"
  28
  29 #include "begnuas.h"
  30
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <ctype.h>
  34 #include <assert.h>
  35
  36 #include "obst.h"
  37 #include "tv.h"
  38 #include "irnode.h"
  39 #include "irprog.h"
  40 #include "entity_t.h"
  41 #include "error.h"
  42
  43 #include "be_t.h"
  44 #include "beemitter.h"
  45 #include "be_dbgout.h"
  46
  47 /** by default, we generate assembler code for the Linux gas */
  48 object_file_format_t  be_gas_object_file_format = OBJECT_FILE_FORMAT_ELF;
  49 bool                  be_gas_emit_types         = true;
  50 char                  be_gas_elf_type_char      = '@';
  51
  52 static be_gas_section_t current_section = (be_gas_section_t) -1;
  53
  54 /**
  55  * An environment containing all needed dumper data.
  56  * Currently we create the file completely in memory first, then
  57  * write it to the disk. This is an artifact from the old C-generating backend
  58  * and even there NOT needed. So we might change it in the future.
  59  */
  60 typedef struct _be_gas_decl_env {
  61         be_gas_section_t     section;
  62         const be_main_env_t *main_env;
  63 } be_gas_decl_env_t;
  64
  65 static void emit_section_macho(be_gas_section_t section)
  66 {
  67         be_gas_section_t  base  = section & GAS_SECTION_TYPE_MASK;
  68         be_gas_section_t  flags = section & ~GAS_SECTION_TYPE_MASK;
  69         const char       *name;
  70
  71         if (current_section == section)
  72                 return;
  73         current_section = section;
  74
  75         /* shortforms */
  76         if (flags == 0) {
  77                 switch (base) {
  78                 case GAS_SECTION_TEXT:            name = "text";          break;
  79                 case GAS_SECTION_DATA:            name = "data";          break;
  80                 case GAS_SECTION_RODATA:          name = "const";         break;
  81                 case GAS_SECTION_BSS:             name = "data";          break;
  82                 case GAS_SECTION_CONSTRUCTORS:    name = "mod_init_func"; break;
  83                 case GAS_SECTION_DESTRUCTORS:     name = "mod_term_func"; break;
  84                 case GAS_SECTION_PIC_TRAMPOLINES: name = "section\t__IMPORT,__jump_table,symbol_stubs,self_modifying_code+pure_instructions,5"; break;
  85                 case GAS_SECTION_PIC_SYMBOLS:     name = "section\t__IMPORT,__pointers,non_lazy_symbol_pointers"; break;
  86                 case GAS_SECTION_CSTRING:         name = "cstring";       break;
  87                 default: panic("unsupported scetion type 0x%X", section);
  88                 }
  89                 be_emit_irprintf("\t.%s\n", name);
  90                 be_emit_write_line();
  91         } else if (flags & GAS_SECTION_FLAG_COMDAT) {
  92                 switch (base) {
  93                 case GAS_SECTION_TEXT:            name = "section __TEXT,__textcoal_nt,coalesced,pure_instructions"; break;
  94                 case GAS_SECTION_BSS:
  95                 case GAS_SECTION_DATA:            name = "section __DATA,__datacoal_nt,coalesced"; break;
  96                 case GAS_SECTION_RODATA:          name = "section __TEXT,__const_coal,coalesced"; break;
  97                 case GAS_SECTION_CSTRING:         name = "section __TEXT,__const_coal,coalesced"; break;
  98                 default: panic("unsupported scetion type 0x%X", section);
  99                 }
 100         } else {
 101                 panic("unsupported section type 0x%X\n", section);
 102         }
 103 }
 104
 105 static void emit_section(be_gas_section_t section, const ir_entity *entity)
 106 {
 107         be_gas_section_t base = section & GAS_SECTION_TYPE_MASK;
 108         be_gas_section_t flags = section & ~GAS_SECTION_TYPE_MASK;
 109         static const char *const basename[] = {
 110                 "text", "data", "rodata", "bss", "ctors", "dtors"
 111         };
 112         static const char *const type[] = {
 113                 "progbits", "progbits", "progbits", "nobits", "init_array", "fini_array"
 114         };
 115
 116         if (be_gas_object_file_format == OBJECT_FILE_FORMAT_MACH_O) {
 117                 emit_section_macho(section);
 118                 return;
 119         }
 120
 121         if (current_section == section && !(section & GAS_SECTION_FLAG_COMDAT))
 122                 return;
 123         current_section = section;
 124
 125         /* shortforms */
 126         if (flags == 0) {
 127                 switch (base) {
 128                 case GAS_SECTION_TEXT:
 129                         be_emit_cstring("\t.text\n");
 130                         be_emit_write_line();
 131                         return;
 132                 case GAS_SECTION_DATA:
 133                         be_emit_cstring("\t.data\n");
 134                         be_emit_write_line();
 135                         return;
 136                 case GAS_SECTION_RODATA:
 137                         be_emit_cstring("\t.section\t.rodata\n");
 138                         be_emit_write_line();
 139                         return;
 140                 case GAS_SECTION_BSS:
 141                         be_emit_cstring("\t.bss\n");
 142                         be_emit_write_line();
 143                         return;
 144                 default:
 145                         break;
 146                 }
 147         }
 148
 149         assert(base < sizeof(basename)/sizeof(basename[0]));
 150         be_emit_cstring("\t.section\t.");
 151         /* section name */
 152         if (flags & GAS_SECTION_FLAG_TLS)
 153                 be_emit_char('t');
 154         be_emit_string(basename[base]);
 155         if (flags & GAS_SECTION_FLAG_COMDAT) {
 156                 be_emit_char('.');
 157                 be_gas_emit_entity(entity);
 158         }
 159
 160         /* section flags */
 161         be_emit_cstring(",\"");
 162         if (be_gas_object_file_format != OBJECT_FILE_FORMAT_COFF)
 163                 be_emit_char('a');
 164         if (base == GAS_SECTION_TEXT)
 165                 be_emit_char('x');
 166         if (base != GAS_SECTION_RODATA && base != GAS_SECTION_TEXT)
 167                 be_emit_char('w');
 168         if (flags & GAS_SECTION_FLAG_TLS)
 169                 be_emit_char('T');
 170         if (flags & GAS_SECTION_FLAG_COMDAT)
 171                 be_emit_char('G');
 172         be_emit_cstring("\",");
 173         be_emit_char(be_gas_elf_type_char);
 174         be_emit_string(type[base]);
 175
 176         if (flags & GAS_SECTION_FLAG_COMDAT) {
 177                 be_emit_char(',');
 178                 be_gas_emit_entity(entity);
 179                 be_emit_cstring(",comdat");
 180         }
 181         be_emit_char('\n');
 182         be_emit_write_line();
 183 }
 184
 185 void be_gas_emit_switch_section(be_gas_section_t section)
 186 {
 187         /* you have to produce a switch_section call with entity manually
 188          * for comdat sections */
 189         assert( !(section & GAS_SECTION_FLAG_COMDAT));
 190
 191         emit_section(section, NULL);
 192 }
 193
 194 static tarval *get_initializer_tarval(const ir_initializer_t *initializer)
 195 {
 196         if (initializer->kind == IR_INITIALIZER_TARVAL)
 197                 return initializer->tarval.value;
 198         if (initializer->kind == IR_INITIALIZER_CONST) {
 199                 ir_node *node = initializer->consti.value;
 200                 if (is_Const(node)) {
 201                         return get_Const_tarval(node);
 202                 }
 203         }
 204         return get_tarval_undefined();
 205 }
 206
 207 static int initializer_is_string_const(const ir_initializer_t *initializer)
 208 {
 209         size_t i, len;
 210         int found_printable = 0;
 211
 212         if (initializer->kind != IR_INITIALIZER_COMPOUND)
 213                 return 0;
 214
 215         len = initializer->compound.n_initializers;
 216         if (len < 1)
 217                 return 0;
 218         for (i = 0; i < len; ++i) {
 219                 int               c;
 220                 tarval           *tv;
 221                 ir_mode          *mode;
 222                 ir_initializer_t *sub_initializer
 223                         = initializer->compound.initializers[i];
 224
 225                 tv = get_initializer_tarval(sub_initializer);
 226                 if (!tarval_is_constant(tv))
 227                         return 0;
 228
 229                 mode = get_tarval_mode(tv);
 230                 if (!mode_is_int(mode) || get_mode_size_bits(mode) != 8)
 231                         return 0;
 232
 233                 c = get_tarval_long(tv);
 234                 if (isgraph(c) || isspace(c))
 235                         found_printable = 1;
 236                 else if (c != 0)
 237                         return 0;
 238
 239                 if (i == len - 1 && c != '\0')
 240                         return 0;
 241         }
 242
 243         return found_printable;
 244 }
 245
 246 static bool initializer_is_null(const ir_initializer_t *initializer)
 247 {
 248         switch (initializer->kind) {
 249         case IR_INITIALIZER_NULL:
 250                 return true;
 251         case IR_INITIALIZER_TARVAL: {
 252                 tarval *tv = initializer->tarval.value;
 253                 return tarval_is_null(tv);
 254         }
 255         case IR_INITIALIZER_CONST: {
 256                 ir_node *value = initializer->consti.value;
 257                 if (!is_Const(value))
 258                         return false;
 259                 return is_Const_null(value);
 260         }
 261         case IR_INITIALIZER_COMPOUND: {
 262                 size_t i;
 263                 for (i = 0; i < initializer->compound.n_initializers; ++i) {
 264                         ir_initializer_t *subinitializer
 265                                 = initializer->compound.initializers[i];
 266                         if (!initializer_is_null(subinitializer))
 267                                 return false;
 268                 }
 269                 return true;
 270         }
 271         }
 272         panic("invalid initializer in initializer_is_null");
 273 }
 274
 275 /**
 276  * Determine if an entity is a string constant
 277  * @param ent The entity
 278  * @return 1 if it is a string constant, 0 otherwise
 279  */
 280 static int entity_is_string_const(const ir_entity *ent)
 281 {
 282         ir_type *type, *element_type;
 283         ir_mode *mode;
 284         int i, c, n;
 285
 286         type = get_entity_type(ent);
 287
 288         /* if it's an array */
 289         if (!is_Array_type(type))
 290                 return 0;
 291
 292         element_type = get_array_element_type(type);
 293
 294         /* and the array's element type is primitive */
 295         if (!is_Primitive_type(element_type))
 296                 return 0;
 297
 298         /* and the mode of the element type is an int of
 299          * the same size as the byte mode */
 300         mode = get_type_mode(element_type);
 301         if (!mode_is_int(mode) || get_mode_size_bits(mode) != 8)
 302                 return 0;
 303
 304         if (ent->initializer != NULL) {
 305                 return initializer_is_string_const(ent->initializer);
 306         } else if (entity_has_compound_ent_values(ent)) {
 307                 int found_printable = 0;
 308                 /* if it contains only printable chars and a 0 at the end */
 309                 n = get_compound_ent_n_values(ent);
 310                 for (i = 0; i < n; ++i) {
 311                         ir_node *irn = get_compound_ent_value(ent, i);
 312                         if (! is_Const(irn))
 313                                 return 0;
 314
 315                         c = (int) get_tarval_long(get_Const_tarval(irn));
 316
 317                         if (isgraph(c) || isspace(c))
 318                                 found_printable = 1;
 319                         else if (c != 0)
 320                                 return 0;
 321
 322                         if (i == n - 1 && c != '\0')
 323                                 return 0;
 324                 }
 325                 return found_printable;
 326         }
 327
 328         return 0;
 329 }
 330
 331 static bool entity_is_null(const ir_entity *entity)
 332 {
 333         if (entity->initializer != NULL) {
 334                 return initializer_is_null(entity->initializer);
 335         } else if (entity_has_compound_ent_values(entity)) {
 336                 /* I'm too lazy to implement this case as compound graph paths will be
 337                  * remove anyway in the future */
 338                 return false;
 339         }
 340         /* uninitialized, NULL is fine */
 341         return true;
 342 }
 343
 344 static bool is_comdat(const ir_entity *entity)
 345 {
 346         ir_linkage linkage = get_entity_linkage(entity);
 347         return (linkage & IR_LINKAGE_MERGE)
 348                 && (linkage & IR_LINKAGE_GARBAGE_COLLECT);
 349 }
 350
 351 static be_gas_section_t determine_basic_section(const ir_entity *entity)
 352 {
 353         ir_linkage linkage;
 354
 355         if (is_method_entity(entity))
 356                 return GAS_SECTION_TEXT;
 357
 358         linkage = get_entity_linkage(entity);
 359         if (linkage & IR_LINKAGE_CONSTANT) {
 360                 /* mach-o is the only one with a cstring section */
 361                 if (be_gas_object_file_format == OBJECT_FILE_FORMAT_MACH_O
 362                                 && entity_is_string_const(entity))
 363                         return GAS_SECTION_CSTRING;
 364
 365                 return GAS_SECTION_RODATA;
 366         }
 367         if (entity_is_null(entity))
 368                 return GAS_SECTION_BSS;
 369
 370         return GAS_SECTION_DATA;
 371 }
 372
 373 static be_gas_section_t determine_section(be_gas_decl_env_t *env,
 374                                           const ir_entity *entity)
 375 {
 376         ir_type *owner = get_entity_owner(entity);
 377
 378         if (owner == get_segment_type(IR_SEGMENT_GLOBAL)) {
 379                 be_gas_section_t section = determine_basic_section(entity);
 380                 if (is_comdat(entity))
 381                         section |= GAS_SECTION_FLAG_COMDAT;
 382                 return section;
 383         } else if (env != NULL && owner == env->main_env->pic_symbols_type) {
 384                 return GAS_SECTION_PIC_SYMBOLS;
 385         } else if (env != NULL && owner == env->main_env->pic_trampolines_type) {
 386                 return GAS_SECTION_PIC_TRAMPOLINES;
 387         } else if (owner == get_segment_type(IR_SEGMENT_CONSTRUCTORS)) {
 388                 return GAS_SECTION_CONSTRUCTORS;
 389         } else if (owner == get_segment_type(IR_SEGMENT_DESTRUCTORS)) {
 390                 return GAS_SECTION_DESTRUCTORS;
 391         } else if (owner == get_segment_type(IR_SEGMENT_THREAD_LOCAL)) {
 392                 be_gas_section_t section = determine_basic_section(entity);
 393                 if (is_comdat(entity))
 394                         section |= GAS_SECTION_FLAG_COMDAT;
 395
 396                 return section | GAS_SECTION_FLAG_TLS;
 397         }
 398
 399         /* the java frontend keeps some functions inside classes */
 400         if (is_Class_type(owner)) {
 401                 return determine_basic_section(entity);
 402         }
 403
 404         panic("Couldn't determine section for %+F?!?", entity);
 405 }
 406
 407 static void emit_weak(const ir_entity *entity)
 408 {
 409         if (be_gas_object_file_format == OBJECT_FILE_FORMAT_MACH_O) {
 410                 be_emit_cstring("\t.weak_reference ");
 411         } else {
 412                 be_emit_cstring("\t.weak ");
 413         }
 414         be_gas_emit_entity(entity);
 415         be_emit_char('\n');
 416         be_emit_write_line();
 417 }
 418
 419 static void emit_visibility(const ir_entity *entity)
 420 {
 421         ir_linkage linkage = get_entity_linkage(entity);
 422
 423         if (get_entity_linkage(entity) & IR_LINKAGE_WEAK) {
 424                 emit_weak(entity);
 425                 /* Note: .weak seems to imply .globl so no need to output .globl */
 426         } else if (get_entity_visibility(entity) == ir_visibility_default) {
 427                 be_emit_cstring(".globl ");
 428                 be_gas_emit_entity(entity);
 429                 be_emit_char('\n');
 430                 be_emit_write_line();
 431         }
 432
 433         if (be_gas_object_file_format == OBJECT_FILE_FORMAT_MACH_O
 434                         && (linkage & IR_LINKAGE_HIDDEN_USER)) {
 435                 be_emit_cstring("\t.no_dead_strip ");
 436                 be_gas_emit_entity(entity);
 437                 be_emit_char('\n');
 438                 be_emit_write_line();
 439         }
 440 }
 441
 442 void be_gas_emit_function_prolog(const ir_entity *entity, unsigned po2alignment)
 443 {
 444         be_gas_section_t section = determine_section(NULL, entity);
 445         emit_section(section, entity);
 446
 447         /* write the begin line (makes the life easier for scripts parsing the
 448          * assembler) */
 449         be_emit_write_line();
 450         be_emit_cstring("# -- Begin  ");
 451         be_gas_emit_entity(entity);
 452         be_emit_char('\n');
 453         be_emit_write_line();
 454
 455         if (po2alignment > 0) {
 456                 const char *fill_byte = "";
 457                 unsigned    maximum_skip = (1 << po2alignment) - 1;
 458                 /* gcc fills space between function with 0x90... */
 459                 if (be_gas_object_file_format == OBJECT_FILE_FORMAT_MACH_O) {
 460                         fill_byte = "0x90";
 461                 }
 462                 be_emit_cstring("\t.p2align ");
 463                 be_emit_irprintf("%u,%s,%u\n", po2alignment, fill_byte, maximum_skip);
 464                 be_emit_write_line();
 465         }
 466         emit_visibility(entity);
 467
 468         switch (be_gas_object_file_format) {
 469         case OBJECT_FILE_FORMAT_ELF:
 470                 be_emit_cstring("\t.type\t");
 471                 be_gas_emit_entity(entity);
 472                 be_emit_cstring(", ");
 473                 be_emit_char(be_gas_elf_type_char);
 474                 be_emit_cstring("function\n");
 475                 be_emit_write_line();
 476                 break;
 477         case OBJECT_FILE_FORMAT_COFF:
 478                 be_emit_cstring("\t.def\t");
 479                 be_gas_emit_entity(entity);
 480                 be_emit_cstring(";");
 481                 if (get_entity_visibility(entity) == ir_visibility_local) {
 482                         be_emit_cstring("\t.scl\t3;");
 483                 } else {
 484                         be_emit_cstring("\t.scl\t2;");
 485                 }
 486                 be_emit_cstring("\t.type\t32;\t.endef\n");
 487                 be_emit_write_line();
 488                 break;
 489         case OBJECT_FILE_FORMAT_MACH_O:
 490                 break;
 491         }
 492         be_gas_emit_entity(entity);
 493         be_emit_cstring(":\n");
 494         be_emit_write_line();
 495 }
 496
 497 void be_gas_emit_function_epilog(const ir_entity *entity)
 498 {
 499         if (be_gas_object_file_format == OBJECT_FILE_FORMAT_ELF) {
 500                 be_emit_cstring("\t.size\t");
 501                 be_gas_emit_entity(entity);
 502                 be_emit_cstring(", .-");
 503                 be_gas_emit_entity(entity);
 504                 be_emit_char('\n');
 505                 be_emit_write_line();
 506         }
 507
 508         be_emit_cstring("# -- End  ");
 509         be_gas_emit_entity(entity);
 510         be_emit_char('\n');
 511         be_emit_write_line();
 512 }
 513
 514 /************************************************************************/
 515
 516 /**
 517  * Output a tarval.
 518  *
 519  * @param tv     the tarval
 520  * @param bytes  the width of the tarvals value in bytes
 521  */
 522 static void emit_arith_tarval(tarval *tv, int bytes)
 523 {
 524         switch (bytes) {
 525         case 1:
 526                 be_emit_irprintf("0x%02x", get_tarval_sub_bits(tv, 0));
 527                 return;
 528
 529         case 2:
 530                 be_emit_irprintf("0x%02x%02x", get_tarval_sub_bits(tv, 1), get_tarval_sub_bits(tv, 0));
 531                 return;
 532
 533         case 4:
 534                 be_emit_irprintf("0x%02x%02x%02x%02x",
 535                         get_tarval_sub_bits(tv, 3), get_tarval_sub_bits(tv, 2), get_tarval_sub_bits(tv, 1), get_tarval_sub_bits(tv, 0));
 536                 return;
 537
 538         case 8:
 539                 be_emit_irprintf("0x%02x%02x%02x%02x%02x%02x%02x%02x",
 540                         get_tarval_sub_bits(tv, 7), get_tarval_sub_bits(tv, 6), get_tarval_sub_bits(tv, 5), get_tarval_sub_bits(tv, 4),
 541                         get_tarval_sub_bits(tv, 3), get_tarval_sub_bits(tv, 2), get_tarval_sub_bits(tv, 1), get_tarval_sub_bits(tv, 0));
 542                 return;
 543
 544         case 12:
 545                 /* Beware: Mixed endian output!  One little endian number emitted as
 546                  * three longs.  Each long initializer is written in big endian. */
 547                 be_emit_irprintf(
 548                         "\t.long\t0x%02x%02x%02x%02x\n"
 549                         "\t.long\t0x%02x%02x%02x%02x\n"
 550                         "\t.long\t0x%02x%02x%02x%02x",
 551                         get_tarval_sub_bits(tv,  3), get_tarval_sub_bits(tv,  2),
 552                         get_tarval_sub_bits(tv,  1), get_tarval_sub_bits(tv,  0),
 553                         get_tarval_sub_bits(tv,  7), get_tarval_sub_bits(tv,  6),
 554                         get_tarval_sub_bits(tv,  5), get_tarval_sub_bits(tv,  4),
 555                         get_tarval_sub_bits(tv, 11), get_tarval_sub_bits(tv, 10),
 556                         get_tarval_sub_bits(tv,  9), get_tarval_sub_bits(tv,  8)
 557                 );
 558                 return;
 559
 560         case 16:
 561                 /* Beware: Mixed endian output!  One little endian number emitted as
 562                  * three longs.  Each long initializer is written in big endian. */
 563                 be_emit_irprintf(
 564                         "\t.long\t0x%02x%02x%02x%02x\n"
 565                         "\t.long\t0x%02x%02x%02x%02x\n"
 566                         "\t.long\t0x%02x%02x%02x%02x\n"
 567                         "\t.long\t0x%02x%02x%02x%02x",
 568                         get_tarval_sub_bits(tv,  3), get_tarval_sub_bits(tv,  2),
 569                         get_tarval_sub_bits(tv,  1), get_tarval_sub_bits(tv,  0),
 570                         get_tarval_sub_bits(tv,  7), get_tarval_sub_bits(tv,  6),
 571                         get_tarval_sub_bits(tv,  5), get_tarval_sub_bits(tv,  4),
 572                         get_tarval_sub_bits(tv, 11), get_tarval_sub_bits(tv, 10),
 573                         get_tarval_sub_bits(tv,  9), get_tarval_sub_bits(tv,  8),
 574                         get_tarval_sub_bits(tv, 15), get_tarval_sub_bits(tv, 14),
 575                         get_tarval_sub_bits(tv, 13), get_tarval_sub_bits(tv, 12)
 576                 );
 577                 return;
 578         }
 579
 580         panic("Can't dump a tarval with %d bytes", bytes);
 581 }
 582
 583 /**
 584  * Return the label prefix for labeled instructions.
 585  */
 586 const char *be_gas_insn_label_prefix(void)
 587 {
 588         return ".LE";
 589 }
 590
 591 /**
 592  * Return the tarval of an atomic initializer.
 593  *
 594  * @param init  a node representing the initializer (on the const code irg)
 595  *
 596  * @return the tarval
 597  */
 598 static tarval *get_atomic_init_tv(ir_node *init)
 599 {
 600         for (;;) {
 601                 ir_mode *mode = get_irn_mode(init);
 602
 603                 switch (get_irn_opcode(init)) {
 604
 605                 case iro_Cast:
 606                         init = get_Cast_op(init);
 607                         continue;
 608
 609                 case iro_Conv:
 610                         init = get_Conv_op(init);
 611                         continue;
 612
 613                 case iro_Const:
 614                         return get_Const_tarval(init);
 615
 616                 case iro_SymConst:
 617                         switch (get_SymConst_kind(init)) {
 618                         case symconst_type_size:
 619                                 return new_tarval_from_long(get_type_size_bytes(get_SymConst_type(init)), mode);
 620
 621                         case symconst_type_align:
 622                                 return new_tarval_from_long(get_type_alignment_bytes(get_SymConst_type(init)), mode);
 623
 624                         case symconst_ofs_ent:
 625                                 return new_tarval_from_long(get_entity_offset(get_SymConst_entity(init)), mode);
 626
 627                         case symconst_enum_const:
 628                                 return get_enumeration_value(get_SymConst_enum(init));
 629
 630                         default:
 631                                 return NULL;
 632                         }
 633
 634                 default:
 635                         return NULL;
 636                 }
 637         }
 638 }
 639
 640 /**
 641  * Dump an atomic value.
 642  *
 643  * @param env   the gas output environment
 644  * @param init  a node representing the atomic value (on the const code irg)
 645  */
 646 static void do_emit_atomic_init(be_gas_decl_env_t *env, ir_node *init)
 647 {
 648         ir_mode *mode = get_irn_mode(init);
 649         int bytes     = get_mode_size_bytes(mode);
 650         tarval *tv;
 651         ir_entity *ent;
 652
 653         init = skip_Id(init);
 654
 655         switch (get_irn_opcode(init)) {
 656         case iro_Cast:
 657                 do_emit_atomic_init(env, get_Cast_op(init));
 658                 return;
 659
 660         case iro_Conv:
 661                 do_emit_atomic_init(env, get_Conv_op(init));
 662                 return;
 663
 664         case iro_Const:
 665                 tv = get_Const_tarval(init);
 666
 667                 /* it's a arithmetic value */
 668                 emit_arith_tarval(tv, bytes);
 669                 return;
 670
 671         case iro_SymConst:
 672                 switch (get_SymConst_kind(init)) {
 673                 case symconst_addr_ent:
 674                         ent = get_SymConst_entity(init);
 675                         be_gas_emit_entity(ent);
 676                         break;
 677
 678                 case symconst_ofs_ent:
 679                         ent = get_SymConst_entity(init);
 680                         be_emit_irprintf("%d", get_entity_offset(ent));
 681                         break;
 682
 683                 case symconst_type_size:
 684                         be_emit_irprintf("%u", get_type_size_bytes(get_SymConst_type(init)));
 685                         break;
 686
 687                 case symconst_type_align:
 688                         be_emit_irprintf("%u", get_type_alignment_bytes(get_SymConst_type(init)));
 689                         break;
 690
 691                 case symconst_enum_const:
 692                         tv = get_enumeration_value(get_SymConst_enum(init));
 693                         emit_arith_tarval(tv, bytes);
 694                         break;
 695
 696                 default:
 697                         assert(!"emit_atomic_init(): don't know how to init from this SymConst");
 698                 }
 699                 return;
 700
 701         case iro_Add:
 702                 if (!mode_is_int(mode) && !mode_is_reference(mode)) {
 703                         panic("Constant must be int or pointer for '+' to work");
 704                 }
 705                 do_emit_atomic_init(env, get_Add_left(init));
 706                 be_emit_cstring(" + ");
 707                 do_emit_atomic_init(env, get_Add_right(init));
 708                 return;
 709
 710         case iro_Sub:
 711                 if (!mode_is_int(mode) && !mode_is_reference(mode)) {
 712                         panic("Constant must be int or pointer for '-' to work");
 713                 }
 714                 do_emit_atomic_init(env, get_Sub_left(init));
 715                 be_emit_cstring(" - ");
 716                 do_emit_atomic_init(env, get_Sub_right(init));
 717                 return;
 718
 719         case iro_Mul:
 720                 if (!mode_is_int(mode) && !mode_is_reference(mode)) {
 721                         panic("Constant must be int or pointer for '*' to work");
 722                 }
 723                 do_emit_atomic_init(env, get_Mul_left(init));
 724                 be_emit_cstring(" * ");
 725                 do_emit_atomic_init(env, get_Mul_right(init));
 726                 return;
 727
 728         case iro_Unknown:
 729                 be_emit_cstring("0");
 730                 return;
 731
 732         default:
 733                 panic("emit_atomic_init(): unsupported IR-node %+F", init);
 734         }
 735 }
 736
 737 /**
 738  * Dumps the type for given size (.byte, .long, ...)
 739  *
 740  * @param size  the size in bytes
 741  */
 742 static void emit_size_type(size_t size)
 743 {
 744         switch (size) {
 745         case 1:
 746                 be_emit_cstring("\t.byte\t");
 747                 break;
 748
 749         case 2:
 750                 be_emit_cstring("\t.short\t");
 751                 break;
 752
 753         case 4:
 754                 be_emit_cstring("\t.long\t");
 755                 break;
 756
 757         case 8:
 758                 be_emit_cstring("\t.quad\t");
 759                 break;
 760
 761         case 10:
 762         case 12:
 763         case 16: /* Note: .octa does not work on mac */
 764                 /* handled in arith */
 765                 break;
 766
 767         default:
 768                 panic("Try to dump a type with %u bytes", (unsigned)size);
 769         }
 770 }
 771
 772 /**
 773  * Emit an atomic value.
 774  *
 775  * @param env   the gas output environment
 776  * @param init  a node representing the atomic value (on the const code irg)
 777  */
 778 static void emit_atomic_init(be_gas_decl_env_t *env, ir_node *init)
 779 {
 780         ir_mode *mode = get_irn_mode(init);
 781         int bytes     = get_mode_size_bytes(mode);
 782
 783         emit_size_type(bytes);
 784         do_emit_atomic_init(env, init);
 785         be_emit_char('\n');
 786         be_emit_write_line();
 787 }
 788
 789 /************************************************************************/
 790 /* Routines to dump global variables                                    */
 791 /************************************************************************/
 792
 793 /**
 794  * Dump a string constant.
 795  * No checks are made!!
 796  *
 797  * @param ent  The entity to dump.
 798  */
 799 static void emit_string_cst(const ir_entity *ent)
 800 {
 801         int      i, len;
 802         int      output_len;
 803         ir_type *type;
 804         int      type_size;
 805         int      remaining_space;
 806
 807         len        = get_compound_ent_n_values(ent);
 808         output_len = len;
 809         if (be_gas_object_file_format == OBJECT_FILE_FORMAT_MACH_O) {
 810                 be_emit_cstring("\t.ascii \"");
 811         } else {
 812                 be_emit_cstring("\t.string \"");
 813                 output_len -= 1;
 814         }
 815
 816         for (i = 0; i < output_len; ++i) {
 817                 ir_node *irn;
 818                 int c;
 819
 820                 irn = get_compound_ent_value(ent, i);
 821                 c = (int) get_tarval_long(get_Const_tarval(irn));
 822
 823                 switch (c) {
 824                 case '"' : be_emit_cstring("\\\""); break;
 825                 case '\n': be_emit_cstring("\\n"); break;
 826                 case '\r': be_emit_cstring("\\r"); break;
 827                 case '\t': be_emit_cstring("\\t"); break;
 828                 case '\\': be_emit_cstring("\\\\"); break;
 829                 default  :
 830                         if (isprint(c))
 831                                 be_emit_char(c);
 832                         else
 833                                 be_emit_irprintf("\\%o", c);
 834                         break;
 835                 }
 836         }
 837         be_emit_cstring("\"\n");
 838         be_emit_write_line();
 839
 840         type            = get_entity_type(ent);
 841         type_size       = get_type_size_bytes(type);
 842         remaining_space = type_size - len;
 843         assert(remaining_space >= 0);
 844         if (remaining_space > 0) {
 845                 be_emit_irprintf("\t.space\t%d\n", remaining_space);
 846         }
 847 }
 848
 849 static void emit_string_initializer(const ir_initializer_t *initializer)
 850 {
 851         size_t i, len;
 852
 853         len = initializer->compound.n_initializers;
 854         if (be_gas_object_file_format == OBJECT_FILE_FORMAT_MACH_O) {
 855                 be_emit_cstring("\t.ascii \"");
 856         } else {
 857                 be_emit_cstring("\t.string \"");
 858                 len -= 1;
 859         }
 860
 861         for (i = 0; i < len; ++i) {
 862                 const ir_initializer_t *sub_initializer
 863                         = get_initializer_compound_value(initializer, i);
 864
 865                 tarval *tv = get_initializer_tarval(sub_initializer);
 866                 int     c  = get_tarval_long(tv);
 867
 868                 switch (c) {
 869                 case '"' : be_emit_cstring("\\\""); break;
 870                 case '\n': be_emit_cstring("\\n"); break;
 871                 case '\r': be_emit_cstring("\\r"); break;
 872                 case '\t': be_emit_cstring("\\t"); break;
 873                 case '\\': be_emit_cstring("\\\\"); break;
 874                 default  :
 875                         if (isprint(c))
 876                                 be_emit_char(c);
 877                         else
 878                                 be_emit_irprintf("\\%o", c);
 879                         break;
 880                 }
 881         }
 882         be_emit_cstring("\"\n");
 883         be_emit_write_line();
 884 }
 885
 886 enum normal_or_bitfield_kind {
 887         NORMAL = 0,
 888         TARVAL,
 889         BITFIELD
 890 };
 891
 892 typedef struct {
 893         enum normal_or_bitfield_kind kind;
 894         union {
 895                 ir_node       *value;
 896                 tarval        *tarval;
 897                 unsigned char  bf_val;
 898         } v;
 899 } normal_or_bitfield;
 900
 901 static int is_type_variable_size(ir_type *type)
 902 {
 903         (void) type;
 904         /* TODO */
 905         return 0;
 906 }
 907
 908 static size_t get_initializer_size(const ir_initializer_t *initializer,
 909                                    ir_type *type)
 910 {
 911         switch (get_initializer_kind(initializer)) {
 912         case IR_INITIALIZER_TARVAL:
 913                 assert(get_tarval_mode(get_initializer_tarval_value(initializer)) == get_type_mode(type));
 914                 return get_type_size_bytes(type);
 915         case IR_INITIALIZER_CONST:
 916         case IR_INITIALIZER_NULL:
 917                 return get_type_size_bytes(type);
 918         case IR_INITIALIZER_COMPOUND:
 919                 if (!is_type_variable_size(type)) {
 920                         return get_type_size_bytes(type);
 921                 } else {
 922                         unsigned n_entries
 923                                 = get_initializer_compound_n_entries(initializer);
 924                         unsigned i;
 925                         unsigned initializer_size = get_type_size_bytes(type);
 926                         for (i = 0; i < n_entries; ++i) {
 927                                 ir_entity *entity = get_compound_member(type, i);
 928                                 ir_type   *type   = get_entity_type(entity);
 929
 930                                 const ir_initializer_t *sub_initializer
 931                                         = get_initializer_compound_value(initializer, i);
 932
 933                                 unsigned offset = get_entity_offset(entity);
 934                                 unsigned size   = get_initializer_size(sub_initializer, type);
 935
 936                                 if (offset + size > initializer_size) {
 937                                         initializer_size = offset + size;
 938                                 }
 939                         }
 940                         return initializer_size;
 941                 }
 942         }
 943
 944         panic("found invalid initializer");
 945 }
 946
 947 #ifndef NDEBUG
 948 static normal_or_bitfield *glob_vals;
 949 static size_t              max_vals;
 950 #endif
 951
 952 static void emit_bitfield(normal_or_bitfield *vals, size_t offset_bits,
 953                           const ir_initializer_t *initializer, ir_type *type)
 954 {
 955         unsigned char  last_bits = 0;
 956         ir_mode       *mode      = get_type_mode(type);
 957         tarval        *tv        = NULL;
 958         unsigned char  curr_bits;
 959         int            value_len;
 960         int            j;
 961
 962         switch (get_initializer_kind(initializer)) {
 963         case IR_INITIALIZER_NULL:
 964                 return;
 965         case IR_INITIALIZER_TARVAL:
 966                 tv = get_initializer_tarval_value(initializer);
 967                 break;
 968         case IR_INITIALIZER_CONST: {
 969                 ir_node *node = get_initializer_const_value(initializer);
 970                 if (!is_Const(node)) {
 971                         panic("bitfield initializer not a Const node");
 972                 }
 973                 tv = get_Const_tarval(node);
 974                 break;
 975         }
 976         case IR_INITIALIZER_COMPOUND:
 977                 panic("bitfield initializer is compound");
 978         }
 979         if (tv == NULL) {
 980                 panic("Couldn't get numeric value for bitfield initializer");
 981         }
 982         tv = tarval_convert_to(tv, get_type_mode(type));
 983
 984         /* normalize offset */
 985         vals        += offset_bits >> 3;
 986         offset_bits &= 7;
 987         value_len    = get_mode_size_bits(mode);
 988
 989         /* combine bits with existing bits */
 990         for (j = 0; value_len + (int) offset_bits > 0; ++j) {
 991                 assert((size_t) (vals - glob_vals) + j < max_vals);
 992                 assert(vals[j].kind == BITFIELD ||
 993                                 (vals[j].kind == NORMAL && vals[j].v.value == NULL));
 994                 vals[j].kind = BITFIELD;
 995                 curr_bits    = get_tarval_sub_bits(tv, j);
 996                 vals[j].v.bf_val
 997                         |= (last_bits >> (8 - offset_bits)) | (curr_bits << offset_bits);
 998                 value_len -= 8;
 999                 last_bits = curr_bits;
1000         }
1001 }
1002
1003 static void emit_ir_initializer(normal_or_bitfield *vals,
1004                                 const ir_initializer_t *initializer,
1005                                 ir_type *type)
1006 {
1007         assert((size_t) (vals - glob_vals) < max_vals);
1008
1009         switch (get_initializer_kind(initializer)) {
1010         case IR_INITIALIZER_NULL:
1011                 return;
1012         case IR_INITIALIZER_TARVAL: {
1013                 size_t i;
1014
1015                 assert(vals->kind != BITFIELD);
1016                 vals->kind     = TARVAL;
1017                 vals->v.tarval = get_initializer_tarval_value(initializer);
1018                 assert(get_type_mode(type) == get_tarval_mode(vals->v.tarval));
1019                 for (i = 1; i < get_type_size_bytes(type); ++i) {
1020                         vals[i].kind    = NORMAL;
1021                         vals[i].v.value = NULL;
1022                 }
1023                 return;
1024         }
1025         case IR_INITIALIZER_CONST: {
1026                 size_t i;
1027
1028                 assert(vals->kind != BITFIELD);
1029                 vals->kind    = NORMAL;
1030                 vals->v.value = get_initializer_const_value(initializer);
1031                 for (i = 1; i < get_type_size_bytes(type); ++i) {
1032                         vals[i].kind    = NORMAL;
1033                         vals[i].v.value = NULL;
1034                 }
1035                 return;
1036         }
1037         case IR_INITIALIZER_COMPOUND: {
1038                 size_t i = 0;
1039                 size_t n = get_initializer_compound_n_entries(initializer);
1040
1041                 if (is_Array_type(type)) {
1042                         ir_type *element_type = get_array_element_type(type);
1043                         size_t   skip         = get_type_size_bytes(element_type);
1044                         size_t   alignment    = get_type_alignment_bytes(element_type);
1045                         size_t   misalign     = skip % alignment;
1046                         if (misalign != 0) {
1047                                 skip += alignment - misalign;
1048                         }
1049
1050                         for (i = 0; i < n; ++i) {
1051                                 ir_initializer_t *sub_initializer
1052                                         = get_initializer_compound_value(initializer, i);
1053
1054                                 emit_ir_initializer(vals, sub_initializer, element_type);
1055
1056                                 vals += skip;
1057                         }
1058                 } else {
1059                         size_t n_members, i;
1060                         assert(is_compound_type(type));
1061                         n_members = get_compound_n_members(type);
1062                         for (i = 0; i < n_members; ++i) {
1063                                 ir_entity        *member    = get_compound_member(type, i);
1064                                 size_t            offset    = get_entity_offset(member);
1065                                 ir_type          *subtype   = get_entity_type(member);
1066                                 ir_mode          *mode      = get_type_mode(subtype);
1067                                 ir_initializer_t *sub_initializer;
1068
1069                                 assert(i < get_initializer_compound_n_entries(initializer));
1070                                 sub_initializer
1071                                         = get_initializer_compound_value(initializer, i);
1072
1073                                 if (mode != NULL) {
1074                                         size_t offset_bits
1075                                                 = get_entity_offset_bits_remainder(member);
1076                                         size_t value_len   = get_mode_size_bits(mode);
1077
1078                                         if (offset_bits != 0 ||
1079                                                 (value_len != 8 && value_len != 16 && value_len != 32
1080                                                  && value_len != 64)) {
1081                                                 emit_bitfield(&vals[offset], offset_bits,
1082                                                               sub_initializer, subtype);
1083                                                 continue;
1084                                         }
1085                                 }
1086
1087                                 emit_ir_initializer(&vals[offset], sub_initializer, subtype);
1088                         }
1089                 }
1090
1091                 return;
1092         }
1093         }
1094         panic("invalid ir_initializer kind found");
1095 }
1096
1097 static void emit_initializer(be_gas_decl_env_t *env, const ir_entity *entity)
1098 {
1099         const ir_initializer_t *initializer = entity->initializer;
1100         ir_type                *type;
1101         normal_or_bitfield     *vals;
1102         size_t                  size;
1103         size_t                  k;
1104
1105         if (initializer_is_string_const(initializer)) {
1106                 emit_string_initializer(initializer);
1107                 return;
1108         }
1109
1110         type = get_entity_type(entity);
1111         size = get_initializer_size(initializer, type);
1112
1113         if (size == 0)
1114                 return;
1115
1116         /*
1117          * In the worst case, every initializer allocates one byte.
1118          * Moreover, initializer might be big, do not allocate on stack.
1119          */
1120         vals = XMALLOCNZ(normal_or_bitfield, size);
1121
1122 #ifndef NDEBUG
1123         glob_vals = vals;
1124         max_vals  = size;
1125 #endif
1126
1127         emit_ir_initializer(vals, initializer, type);
1128
1129         /* now write values sorted */
1130         for (k = 0; k < size; ) {
1131                 int space     = 0;
1132                 int elem_size = 1;
1133                 if (vals[k].kind == NORMAL) {
1134                         if (vals[k].v.value != NULL) {
1135                                 emit_atomic_init(env, vals[k].v.value);
1136                                 elem_size = get_mode_size_bytes(get_irn_mode(vals[k].v.value));
1137                         } else {
1138                                 elem_size = 0;
1139                         }
1140                 } else if (vals[k].kind == TARVAL) {
1141                         tarval *tv   = vals[k].v.tarval;
1142                         size_t  size = get_mode_size_bytes(get_tarval_mode(tv));
1143
1144                         assert(tv != NULL);
1145
1146                         elem_size = size;
1147                         emit_size_type(size);
1148                         emit_arith_tarval(tv, size);
1149                         be_emit_char('\n');
1150                         be_emit_write_line();
1151                 } else {
1152                         assert(vals[k].kind == BITFIELD);
1153                         be_emit_irprintf("\t.byte\t%d\n", vals[k].v.bf_val);
1154                         be_emit_write_line();
1155                 }
1156
1157                 k += elem_size;
1158                 while (k < size && vals[k].kind == NORMAL && vals[k].v.value == NULL) {
1159                         ++space;
1160                         ++k;
1161                 }
1162
1163                 /* a gap */
1164                 if (space > 0) {
1165                         be_emit_irprintf("\t.space\t%d\n", space);
1166                         be_emit_write_line();
1167                 }
1168         }
1169         xfree(vals);
1170 }
1171
1172 static void emit_compound_graph_init(be_gas_decl_env_t *env,
1173                                      const ir_entity *ent)
1174 {
1175         normal_or_bitfield *vals;
1176         int i, j, n;
1177         unsigned k, last_ofs;
1178
1179         if (entity_is_string_const(ent)) {
1180                 emit_string_cst(ent);
1181                 return;
1182         }
1183
1184         n = get_compound_ent_n_values(ent);
1185
1186         /* Find the initializer size. Sorrily gcc support a nasty feature:
1187            The last field of a compound may be a flexible array. This allows
1188            initializers bigger than the type size. */
1189         last_ofs = get_type_size_bytes(get_entity_type(ent));
1190         for (i = 0; i < n; ++i) {
1191                 unsigned offset         = get_compound_ent_value_offset_bytes(ent, i);
1192                 unsigned bits_remainder = get_compound_ent_value_offset_bit_remainder(ent, i);
1193                 ir_node  *value         = get_compound_ent_value(ent, i);
1194                 unsigned value_len      = get_mode_size_bits(get_irn_mode(value));
1195
1196                 offset += (value_len + bits_remainder + 7) >> 3;
1197
1198                 if (offset > last_ofs) {
1199                         last_ofs = offset;
1200                 }
1201         }
1202
1203         /*
1204          * In the worst case, every initializer allocates one byte.
1205          * Moreover, initializer might be big, do not allocate on stack.
1206          */
1207         vals = XMALLOCNZ(normal_or_bitfield, last_ofs);
1208
1209         /* collect the values and store them at the offsets */
1210         for (i = 0; i < n; ++i) {
1211                 unsigned offset      = get_compound_ent_value_offset_bytes(ent, i);
1212                 int      offset_bits = get_compound_ent_value_offset_bit_remainder(ent, i);
1213                 ir_node  *value      = get_compound_ent_value(ent, i);
1214                 int      value_len   = get_mode_size_bits(get_irn_mode(value));
1215
1216                 assert(offset_bits >= 0);
1217
1218                 if (offset_bits != 0 ||
1219                                 (value_len != 8 && value_len != 16 && value_len != 32 && value_len != 64)) {
1220                         tarval *tv = get_atomic_init_tv(value);
1221                         unsigned char curr_bits, last_bits = 0;
1222                         if (tv == NULL) {
1223                                 panic("Couldn't get numeric value for bitfield initializer '%s'",
1224                                                 get_entity_ld_name(ent));
1225                         }
1226                         /* normalize offset */
1227                         offset += offset_bits >> 3;
1228                         offset_bits &= 7;
1229
1230                         for (j = 0; value_len + offset_bits > 0; ++j) {
1231                                 assert(offset + j < last_ofs);
1232                                 assert(vals[offset + j].kind == BITFIELD || vals[offset + j].v.value == NULL);
1233                                 vals[offset + j].kind = BITFIELD;
1234                                 curr_bits = get_tarval_sub_bits(tv, j);
1235                                 vals[offset + j].v.bf_val |= (last_bits >> (8 - offset_bits)) | (curr_bits << offset_bits);
1236                                 value_len -= 8;
1237                                 last_bits = curr_bits;
1238                         }
1239                 } else {
1240                         int i;
1241
1242                         assert(offset < last_ofs);
1243                         assert(vals[offset].kind == NORMAL);
1244                         for (i = 1; i < value_len / 8; ++i) {
1245                                 assert(vals[offset + i].v.value == NULL);
1246                         }
1247                         vals[offset].v.value = value;
1248                 }
1249         }
1250
1251         /* now write them sorted */
1252         for (k = 0; k < last_ofs; ) {
1253                 int space = 0, skip = 0;
1254                 if (vals[k].kind == NORMAL) {
1255                         if (vals[k].v.value != NULL) {
1256                                 emit_atomic_init(env, vals[k].v.value);
1257                                 skip = get_mode_size_bytes(get_irn_mode(vals[k].v.value)) - 1;
1258                         } else {
1259                                 space = 1;
1260                         }
1261                 } else {
1262                         assert(vals[k].kind == BITFIELD);
1263                         be_emit_irprintf("\t.byte\t%d\n", vals[k].v.bf_val);
1264                 }
1265
1266                 ++k;
1267                 while (k < last_ofs && vals[k].kind == NORMAL && vals[k].v.value == NULL) {
1268                         ++space;
1269                         ++k;
1270                 }
1271                 space -= skip;
1272                 assert(space >= 0);
1273
1274                 /* a gap */
1275                 if (space > 0) {
1276                         be_emit_irprintf("\t.space\t%d\n", space);
1277                         be_emit_write_line();
1278                 }
1279         }
1280         xfree(vals);
1281 }
1282
1283 static void emit_align(unsigned p2alignment)
1284 {
1285         be_emit_irprintf("\t.p2align\t%u\n", log2_floor(p2alignment));
1286         be_emit_write_line();
1287 }
1288
1289 static unsigned get_effective_entity_alignment(const ir_entity *entity)
1290 {
1291         unsigned alignment = get_entity_alignment(entity);
1292         if (alignment == 0) {
1293                 ir_type *type = get_entity_type(entity);
1294                 alignment     = get_type_alignment_bytes(type);
1295         }
1296         return alignment;
1297 }
1298
1299 static void emit_common(const ir_entity *entity)
1300 {
1301         unsigned size      = get_type_size_bytes(get_entity_type(entity));
1302         unsigned alignment = get_effective_entity_alignment(entity);
1303
1304         if (get_entity_linkage(entity) & IR_LINKAGE_WEAK) {
1305                 emit_weak(entity);
1306         }
1307
1308         switch (be_gas_object_file_format) {
1309         case OBJECT_FILE_FORMAT_MACH_O:
1310                 be_emit_cstring("\t.comm ");
1311                 be_gas_emit_entity(entity);
1312                 be_emit_irprintf(",%u,%u\n", size, log2_floor(alignment));
1313                 be_emit_write_line();
1314                 return;
1315         case OBJECT_FILE_FORMAT_ELF:
1316                 be_emit_cstring("\t.comm ");
1317                 be_gas_emit_entity(entity);
1318                 be_emit_irprintf(",%u,%u\n", size, alignment);
1319                 be_emit_write_line();
1320                 return;
1321         case OBJECT_FILE_FORMAT_COFF:
1322                 be_emit_cstring("\t.comm ");
1323                 be_gas_emit_entity(entity);
1324                 be_emit_irprintf(",%u # %u\n", size, alignment);
1325                 be_emit_write_line();
1326                 return;
1327         }
1328         panic("invalid object file format");
1329 }
1330
1331 static void emit_local_common(const ir_entity *entity)
1332 {
1333         unsigned size      = get_type_size_bytes(get_entity_type(entity));
1334         unsigned alignment = get_effective_entity_alignment(entity);
1335
1336         if (get_entity_linkage(entity) & IR_LINKAGE_WEAK) {
1337                 emit_weak(entity);
1338         }
1339
1340         switch (be_gas_object_file_format) {
1341         case OBJECT_FILE_FORMAT_MACH_O:
1342                 be_emit_cstring("\t.lcomm ");
1343                 be_gas_emit_entity(entity);
1344                 be_emit_irprintf(",%u,%u\n", size, log2_floor(alignment));
1345                 be_emit_write_line();
1346                 return;
1347         case OBJECT_FILE_FORMAT_ELF:
1348                 be_emit_cstring("\t.local ");
1349                 be_gas_emit_entity(entity);
1350                 be_emit_cstring("\n");
1351                 be_emit_write_line();
1352                 be_emit_cstring("\t.comm ");
1353                 be_gas_emit_entity(entity);
1354                 be_emit_irprintf(",%u,%u\n", size, alignment);
1355                 be_emit_write_line();
1356                 return;
1357         case OBJECT_FILE_FORMAT_COFF:
1358                 be_emit_cstring("\t.lcomm ");
1359                 be_gas_emit_entity(entity);
1360                 be_emit_irprintf(",%u # %u\n", size, alignment);
1361                 be_emit_write_line();
1362                 return;
1363         }
1364         panic("invalid object file format");
1365 }
1366
1367 static void emit_indirect_symbol(const ir_entity *entity, be_gas_section_t section)
1368 {
1369         /* we can only do PIC code on macho so far */
1370         assert(be_gas_object_file_format == OBJECT_FILE_FORMAT_MACH_O);
1371
1372         be_gas_emit_entity(entity);
1373         be_emit_cstring(":\n");
1374         be_emit_write_line();
1375         be_emit_cstring("\t.indirect_symbol ");
1376         be_emit_ident(get_entity_ident(entity));
1377         be_emit_char('\n');
1378         be_emit_write_line();
1379         if (section == GAS_SECTION_PIC_TRAMPOLINES) {
1380                 be_emit_cstring("\thlt ; hlt ; hlt ; hlt ; hlt\n");
1381                 be_emit_write_line();
1382         } else {
1383                 assert(section == GAS_SECTION_PIC_SYMBOLS);
1384                 be_emit_cstring("\t.long 0\n");
1385                 be_emit_write_line();
1386         }
1387 }
1388
1389 char const *be_gas_get_private_prefix(void)
1390 {
1391         return
1392                 be_gas_object_file_format == OBJECT_FILE_FORMAT_MACH_O ? "L" :
1393                 ".L";
1394 }
1395
1396 void be_gas_emit_entity(const ir_entity *entity)
1397 {
1398         if (entity->type == firm_code_type) {
1399                 ir_label_t label = get_entity_label(entity);
1400                 be_emit_irprintf("%s_%lu", be_gas_get_private_prefix(), label);
1401                 return;
1402         }
1403
1404         if (get_entity_visibility(entity) == ir_visibility_private) {
1405                 be_emit_string(be_gas_get_private_prefix());
1406         }
1407         be_emit_ident(get_entity_ld_ident(entity));
1408 }
1409
1410 void be_gas_emit_block_name(const ir_node *block)
1411 {
1412         if (has_Block_entity(block)) {
1413                 ir_entity *entity = get_Block_entity(block);
1414                 be_gas_emit_entity(entity);
1415         } else {
1416                 be_emit_irprintf("%s%ld", be_gas_get_private_prefix(), get_irn_node_nr(block));
1417         }
1418 }
1419
1420 /**
1421  * Dump a global entity.
1422  *
1423  * @param env  the gas output environment
1424  * @param ent  the entity to be dumped
1425  */
1426 static void emit_global(be_gas_decl_env_t *env, const ir_entity *entity)
1427 {
1428         ir_type          *type       = get_entity_type(entity);
1429         ident            *ld_ident   = get_entity_ld_ident(entity);
1430         unsigned          alignment  = get_effective_entity_alignment(entity);
1431         be_gas_section_t  section    = determine_section(env, entity);
1432         ir_visibility     visibility = get_entity_visibility(entity);
1433         ir_linkage        linkage    = get_entity_linkage(entity);
1434
1435         /* block labels are already emittet in the code */
1436         if (type == firm_code_type)
1437                 return;
1438
1439         /* we already emitted all methods. Except for the trampolines which
1440          * the assembler/linker generates */
1441         if (is_Method_type(type) && section != GAS_SECTION_PIC_TRAMPOLINES) {
1442                 /* functions with graph are already emitted with
1443                  * be_gas_emit_function_prolog */
1444                 if (get_entity_irg(entity) == NULL) {
1445                         emit_visibility(entity);
1446                 }
1447                 return;
1448         }
1449
1450         be_dbg_variable(entity);
1451
1452         if (section == GAS_SECTION_BSS) {
1453                 ir_visibility visibility = get_entity_visibility(entity);
1454
1455                 switch (visibility) {
1456                 case ir_visibility_local:
1457                 case ir_visibility_private:
1458                         emit_local_common(entity);
1459                         return;
1460                 case ir_visibility_default:
1461                         if (linkage & IR_LINKAGE_MERGE) {
1462                                 emit_common(entity);
1463                                 return;
1464                         }
1465                         break;
1466                 case ir_visibility_external:
1467                         if (linkage & IR_LINKAGE_MERGE)
1468                                 panic("merge link semantic not supported for extern entities");
1469                         break;
1470                 }
1471         }
1472
1473         emit_visibility(entity);
1474         if (visibility == ir_visibility_external) {
1475                 /* nothing to do for externally defined values */
1476                 return;
1477         }
1478
1479         if (!is_po2(alignment))
1480                 panic("alignment not a power of 2");
1481
1482         emit_section(section, entity);
1483
1484         if (section == GAS_SECTION_PIC_TRAMPOLINES
1485                         || section == GAS_SECTION_PIC_SYMBOLS) {
1486                 emit_indirect_symbol(entity, section);
1487                 return;
1488         }
1489
1490         /* alignment */
1491         if (alignment > 1) {
1492                 emit_align(alignment);
1493         }
1494         if (be_gas_object_file_format == OBJECT_FILE_FORMAT_ELF
1495                         && be_gas_emit_types) {
1496                 be_emit_cstring("\t.type\t");
1497                 be_gas_emit_entity(entity);
1498                 be_emit_cstring(", ");
1499                 be_emit_char(be_gas_elf_type_char);
1500                 be_emit_cstring("object\n\t.size\t");\
1501                 be_gas_emit_entity(entity);
1502                 be_emit_irprintf(", %u\n", get_type_size_bytes(type));
1503         }
1504
1505         if (get_id_str(ld_ident)[0] != '\0') {
1506             be_gas_emit_entity(entity);
1507                 be_emit_cstring(":\n");
1508                 be_emit_write_line();
1509         }
1510
1511         if (entity_is_null(entity)) {
1512                 be_emit_irprintf("\t.space %u\n", get_type_size_bytes(type));
1513                 be_emit_write_line();
1514         } else if (entity_has_compound_ent_values(entity)) {
1515                 emit_compound_graph_init(env, entity);
1516         } else {
1517                 assert(entity->initializer != NULL);
1518                 emit_initializer(env, entity);
1519         }
1520 }
1521
1522 /**
1523  * Dumps declarations of global variables and the initialization code.
1524  *
1525  * @param gt                a global like type, either the global or the TLS one
1526  * @param env               an environment
1527  */
1528 static void be_gas_emit_globals(ir_type *gt, be_gas_decl_env_t *env)
1529 {
1530         int i, n = get_compound_n_members(gt);
1531
1532         for (i = 0; i < n; i++) {
1533                 ir_entity *ent = get_compound_member(gt, i);
1534                 emit_global(env, ent);
1535         }
1536 }
1537
1538 /************************************************************************/
1539
1540 /* Generate all entities. */
1541 void be_gas_emit_decls(const be_main_env_t *main_env)
1542 {
1543         be_gas_decl_env_t env;
1544         memset(&env, 0, sizeof(env));
1545
1546         /* dump global type */
1547         env.main_env = main_env;
1548         env.section  = (be_gas_section_t) -1;
1549
1550         be_gas_emit_globals(get_glob_type(), &env);
1551         be_gas_emit_globals(get_tls_type(), &env);
1552         be_gas_emit_globals(get_segment_type(IR_SEGMENT_CONSTRUCTORS), &env);
1553         be_gas_emit_globals(get_segment_type(IR_SEGMENT_DESTRUCTORS), &env);
1554         be_gas_emit_globals(main_env->pic_symbols_type, &env);
1555         be_gas_emit_globals(main_env->pic_trampolines_type, &env);
1556
1557         /**
1558          * ".subsections_via_symbols marks object files which are OK to divide
1559          * their section contents into individual blocks".
1560          * From my understanding this means no label points in the middle of an
1561          * object which we want to address as a whole. Firm code should be fine
1562          * with this.
1563          */
1564         if (be_gas_object_file_format == OBJECT_FILE_FORMAT_MACH_O) {
1565                 be_emit_cstring("\t.subsections_via_symbols\n");
1566                 be_emit_write_line();
1567         }
1568 }