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