1 /* elfos.h -- operating system specific defines to be used when 2 targeting GCC for some generic ELF system 3 Copyright (C) 1991-2022 Free Software Foundation, Inc. 4 Based on svr4.h contributed by Ron Guilmette (rfg@netcom.com). 5 6 This file is part of GCC. 7 8 GCC is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3, or (at your option) 11 any later version. 12 13 GCC is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 Under Section 7 of GPL version 3, you are granted additional 19 permissions described in the GCC Runtime Library Exception, version 20 3.1, as published by the Free Software Foundation. 21 22 You should have received a copy of the GNU General Public License and 23 a copy of the GCC Runtime Library Exception along with this program; 24 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 25 <http://www.gnu.org/licenses/>. */ 26 27 #define TARGET_OBJFMT_CPP_BUILTINS() \ 28 do \ 29 { \ 30 builtin_define ("__ELF__"); \ 31 } \ 32 while (0) 33 34 /* Define a symbol indicating that we are using elfos.h. 35 Some CPU specific configuration files use this. */ 36 #define USING_ELFOS_H 37 38 /* The prefix to add to user-visible assembler symbols. 39 40 For ELF systems the convention is *not* to prepend a leading 41 underscore onto user-level symbol names. */ 42 43 #undef USER_LABEL_PREFIX 44 #define USER_LABEL_PREFIX "" 45 46 /* The biggest alignment supported by ELF in bits. 32-bit ELF 47 supports section alignment up to (0x80000000 * 8), while 48 64-bit ELF supports (0x8000000000000000 * 8). If this macro 49 is not defined, the default is the largest alignment supported 50 by 32-bit ELF and representable on a 32-bit host. Use this 51 macro to limit the alignment which can be specified using 52 the `__attribute__ ((aligned (N)))' construct. */ 53 #ifndef MAX_OFILE_ALIGNMENT 54 #define MAX_OFILE_ALIGNMENT (((unsigned int) 1 << 28) * 8) 55 #endif 56 57 /* Use periods rather than dollar signs in special g++ assembler names. */ 58 59 #define NO_DOLLAR_IN_LABEL 60 61 /* Writing `int' for a bit-field forces int alignment for the structure. */ 62 63 #ifndef PCC_BITFIELD_TYPE_MATTERS 64 #define PCC_BITFIELD_TYPE_MATTERS 1 65 #endif 66 67 /* All ELF targets can support DWARF-2. */ 68 69 #define DWARF2_DEBUGGING_INFO 1 70 71 /* All ELF targets can support CTF. */ 72 73 #define CTF_DEBUGGING_INFO 1 74 75 /* All ELF targets can support BTF. */ 76 77 #define BTF_DEBUGGING_INFO 1 78 79 /* The GNU tools operate better with dwarf2, and it is required by some 80 psABI's. Since we don't have any native tools to be compatible with, 81 default to dwarf2. */ 82 83 #ifndef PREFERRED_DEBUGGING_TYPE 84 #define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG 85 #endif 86 87 /* All SVR4 targets use the ELF object file format. */ 88 #define OBJECT_FORMAT_ELF 89 90 91 /* Output #ident as a .ident. */ 92 93 #undef TARGET_ASM_OUTPUT_IDENT 94 #define TARGET_ASM_OUTPUT_IDENT default_asm_output_ident_directive 95 96 #undef SET_ASM_OP 97 #define SET_ASM_OP "\t.set\t" 98 99 /* Most svr4 assemblers want a .file directive at the beginning of 100 their input file. */ 101 #define TARGET_ASM_FILE_START_FILE_DIRECTIVE true 102 103 /* This is how to allocate empty space in some section. The .zero 104 pseudo-op is used for this on most svr4 assemblers. */ 105 106 #define SKIP_ASM_OP "\t.zero\t" 107 108 #undef ASM_OUTPUT_SKIP 109 #define ASM_OUTPUT_SKIP(FILE, SIZE) \ 110 fprintf ((FILE), "%s" HOST_WIDE_INT_PRINT_UNSIGNED "\n",\ 111 SKIP_ASM_OP, (SIZE)) 112 113 /* This is how to store into the string LABEL 114 the symbol_ref name of an internal numbered label where 115 PREFIX is the class of label and NUM is the number within the class. 116 This is suitable for output with `assemble_name'. 117 118 For most svr4 systems, the convention is that any symbol which begins 119 with a period is not put into the linker symbol table by the assembler. */ 120 121 #undef ASM_GENERATE_INTERNAL_LABEL 122 #define ASM_GENERATE_INTERNAL_LABEL(LABEL, PREFIX, NUM) \ 123 do \ 124 { \ 125 char *__p; \ 126 (LABEL)[0] = '*'; \ 127 (LABEL)[1] = '.'; \ 128 __p = stpcpy (&(LABEL)[2], PREFIX); \ 129 sprint_ul (__p, (unsigned long) (NUM)); \ 130 } \ 131 while (0) 132 133 /* Output the label which precedes a jumptable. Note that for all svr4 134 systems where we actually generate jumptables (which is to say every 135 svr4 target except i386, where we use casesi instead) we put the jump- 136 tables into the .rodata section and since other stuff could have been 137 put into the .rodata section prior to any given jumptable, we have to 138 make sure that the location counter for the .rodata section gets pro- 139 perly re-aligned prior to the actual beginning of the jump table. */ 140 141 #undef ALIGN_ASM_OP 142 #define ALIGN_ASM_OP "\t.align\t" 143 144 #ifndef ASM_OUTPUT_BEFORE_CASE_LABEL 145 #define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE, PREFIX, NUM, TABLE) \ 146 ASM_OUTPUT_ALIGN ((FILE), 2) 147 #endif 148 149 #undef ASM_OUTPUT_CASE_LABEL 150 #define ASM_OUTPUT_CASE_LABEL(FILE, PREFIX, NUM, JUMPTABLE) \ 151 do \ 152 { \ 153 ASM_OUTPUT_BEFORE_CASE_LABEL (FILE, PREFIX, NUM, JUMPTABLE); \ 154 (*targetm.asm_out.internal_label) (FILE, PREFIX, NUM); \ 155 } \ 156 while (0) 157 158 /* The standard SVR4 assembler seems to require that certain builtin 159 library routines (e.g. .udiv) be explicitly declared as .globl 160 in each assembly file where they are referenced. */ 161 162 #define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, FUN) \ 163 (*targetm.asm_out.globalize_label) (FILE, XSTR (FUN, 0)) 164 165 /* This says how to output assembler code to declare an 166 uninitialized external linkage data object. Under SVR4, 167 the linker seems to want the alignment of data objects 168 to depend on their types. We do exactly that here. */ 169 170 #define COMMON_ASM_OP "\t.comm\t" 171 172 #undef ASM_OUTPUT_ALIGNED_COMMON 173 #define ASM_OUTPUT_ALIGNED_COMMON(FILE, NAME, SIZE, ALIGN) \ 174 do \ 175 { \ 176 fprintf ((FILE), "%s", COMMON_ASM_OP); \ 177 assemble_name ((FILE), (NAME)); \ 178 fprintf ((FILE), "," HOST_WIDE_INT_PRINT_UNSIGNED ",%u\n", \ 179 (SIZE), (ALIGN) / BITS_PER_UNIT); \ 180 } \ 181 while (0) 182 183 /* This says how to output assembler code to declare an 184 uninitialized internal linkage data object. Under SVR4, 185 the linker seems to want the alignment of data objects 186 to depend on their types. We do exactly that here. */ 187 188 #define LOCAL_ASM_OP "\t.local\t" 189 190 #undef ASM_OUTPUT_ALIGNED_LOCAL 191 #define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGN) \ 192 do \ 193 { \ 194 fprintf ((FILE), "%s", LOCAL_ASM_OP); \ 195 assemble_name ((FILE), (NAME)); \ 196 fprintf ((FILE), "\n"); \ 197 ASM_OUTPUT_ALIGNED_COMMON (FILE, NAME, SIZE, ALIGN); \ 198 } \ 199 while (0) 200 201 /* This is the pseudo-op used to generate a contiguous sequence of byte 202 values from a double-quoted string WITHOUT HAVING A TERMINATING NUL 203 AUTOMATICALLY APPENDED. This is the same for most svr4 assemblers. */ 204 205 #undef ASCII_DATA_ASM_OP 206 #define ASCII_DATA_ASM_OP "\t.ascii\t" 207 208 /* Support a read-only data section. */ 209 #define READONLY_DATA_SECTION_ASM_OP "\t.section\t.rodata" 210 211 /* On svr4, we *do* have support for the .init and .fini sections, and we 212 can put stuff in there to be executed before and after `main'. We let 213 crtstuff.c and other files know this by defining the following symbols. 214 The definitions say how to change sections to the .init and .fini 215 sections. This is the same for all known svr4 assemblers. */ 216 217 #define INIT_SECTION_ASM_OP "\t.section\t.init" 218 #define FINI_SECTION_ASM_OP "\t.section\t.fini" 219 220 /* Output assembly directive to move to the beginning of current section. */ 221 #ifdef HAVE_GAS_SUBSECTION_ORDERING 222 # define ASM_SECTION_START_OP "\t.subsection\t-1" 223 # define ASM_OUTPUT_SECTION_START(FILE) \ 224 fprintf ((FILE), "%s\n", ASM_SECTION_START_OP) 225 #endif 226 227 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1) 228 229 /* Switch into a generic section. */ 230 #define TARGET_ASM_NAMED_SECTION default_elf_asm_named_section 231 232 #undef TARGET_ASM_SELECT_RTX_SECTION 233 #define TARGET_ASM_SELECT_RTX_SECTION default_elf_select_rtx_section 234 #undef TARGET_ASM_SELECT_SECTION 235 #define TARGET_ASM_SELECT_SECTION default_elf_select_section 236 #undef TARGET_HAVE_SWITCHABLE_BSS_SECTIONS 237 #define TARGET_HAVE_SWITCHABLE_BSS_SECTIONS true 238 239 /* Define the strings used for the special svr4 .type and .size directives. 240 These strings generally do not vary from one system running svr4 to 241 another, but if a given system (e.g. m88k running svr) needs to use 242 different pseudo-op names for these, they may be overridden in the 243 file which includes this one. */ 244 245 #define TYPE_ASM_OP "\t.type\t" 246 #define SIZE_ASM_OP "\t.size\t" 247 248 /* This is how we tell the assembler that a symbol is weak. */ 249 250 #define ASM_WEAKEN_LABEL(FILE, NAME) \ 251 do \ 252 { \ 253 fputs ("\t.weak\t", (FILE)); \ 254 assemble_name ((FILE), (NAME)); \ 255 fputc ('\n', (FILE)); \ 256 } \ 257 while (0) 258 259 #define ASM_OUTPUT_SYMVER_DIRECTIVE(FILE, NAME, NAME2) \ 260 do \ 261 { \ 262 fputs ("\t.symver\t", (FILE)); \ 263 assemble_name ((FILE), (NAME)); \ 264 fputs (", ", (FILE)); \ 265 assemble_name ((FILE), (NAME2)); \ 266 fputc ('\n', (FILE)); \ 267 } \ 268 while (0) 269 270 /* The following macro defines the format used to output the second 271 operand of the .type assembler directive. Different svr4 assemblers 272 expect various different forms for this operand. The one given here 273 is just a default. You may need to override it in your machine- 274 specific tm.h file (depending upon the particulars of your assembler). */ 275 276 #define TYPE_OPERAND_FMT "@%s" 277 278 /* Write the extra assembler code needed to declare a function's result. 279 Most svr4 assemblers don't require any special declaration of the 280 result value, but there are exceptions. */ 281 282 #ifndef ASM_DECLARE_RESULT 283 #define ASM_DECLARE_RESULT(FILE, RESULT) 284 #endif 285 286 /* These macros generate the special .type and .size directives which 287 are used to set the corresponding fields of the linker symbol table 288 entries in an ELF object file under SVR4. These macros also output 289 the starting labels for the relevant functions/objects. */ 290 291 /* Write the extra assembler code needed to declare a function properly. 292 Some svr4 assemblers need to also have something extra said about the 293 function's return value. We allow for that here. */ 294 295 #ifndef ASM_DECLARE_FUNCTION_NAME 296 #define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL) \ 297 do \ 298 { \ 299 ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "function"); \ 300 ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL)); \ 301 ASM_OUTPUT_FUNCTION_LABEL (FILE, NAME, DECL); \ 302 } \ 303 while (0) 304 #endif 305 306 /* Write the extra assembler code needed to declare the name of a 307 cold function partition properly. Some svr4 assemblers need to also 308 have something extra said about the function's return value. We 309 allow for that here. */ 310 311 #ifndef ASM_DECLARE_COLD_FUNCTION_NAME 312 #define ASM_DECLARE_COLD_FUNCTION_NAME(FILE, NAME, DECL) \ 313 do \ 314 { \ 315 ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "function"); \ 316 ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL)); \ 317 ASM_OUTPUT_FUNCTION_LABEL (FILE, NAME, DECL); \ 318 } \ 319 while (0) 320 #endif 321 322 /* Write the extra assembler code needed to declare an object properly. */ 323 324 #ifdef HAVE_GAS_GNU_UNIQUE_OBJECT 325 #define USE_GNU_UNIQUE_OBJECT flag_gnu_unique 326 #else 327 #define USE_GNU_UNIQUE_OBJECT 0 328 #endif 329 330 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL) \ 331 do \ 332 { \ 333 HOST_WIDE_INT size; \ 334 \ 335 /* For template static data member instantiations or \ 336 inline fn local statics and their guard variables, use \ 337 gnu_unique_object so that they will be combined even under \ 338 RTLD_LOCAL. Don't use gnu_unique_object for typeinfo, \ 339 vtables and other read-only artificial decls. */ \ 340 if (USE_GNU_UNIQUE_OBJECT && DECL_ONE_ONLY (DECL) \ 341 && (!DECL_ARTIFICIAL (DECL) || !TREE_READONLY (DECL))) \ 342 ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "gnu_unique_object"); \ 343 else \ 344 ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object"); \ 345 \ 346 size_directive_output = 0; \ 347 if (!flag_inhibit_size_directive \ 348 && (DECL) && DECL_SIZE (DECL)) \ 349 { \ 350 size_directive_output = 1; \ 351 size = tree_to_uhwi (DECL_SIZE_UNIT (DECL)); \ 352 ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size); \ 353 } \ 354 \ 355 ASM_OUTPUT_LABEL (FILE, NAME); \ 356 } \ 357 while (0) 358 359 /* Output the size directive for a decl in rest_of_decl_compilation 360 in the case where we did not do so before the initializer. 361 Once we find the error_mark_node, we know that the value of 362 size_directive_output was set 363 by ASM_DECLARE_OBJECT_NAME when it was run for the same decl. */ 364 365 #undef ASM_FINISH_DECLARE_OBJECT 366 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)\ 367 do \ 368 { \ 369 const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0); \ 370 HOST_WIDE_INT size; \ 371 \ 372 if (!flag_inhibit_size_directive \ 373 && DECL_SIZE (DECL) \ 374 && ! AT_END && TOP_LEVEL \ 375 && DECL_INITIAL (DECL) == error_mark_node \ 376 && !size_directive_output) \ 377 { \ 378 size_directive_output = 1; \ 379 size = tree_to_uhwi (DECL_SIZE_UNIT (DECL)); \ 380 ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size); \ 381 } \ 382 } \ 383 while (0) 384 385 /* This is how to declare the size of a function. */ 386 #ifndef ASM_DECLARE_FUNCTION_SIZE 387 #define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL) \ 388 do \ 389 { \ 390 if (!flag_inhibit_size_directive) \ 391 ASM_OUTPUT_MEASURED_SIZE (FILE, FNAME); \ 392 } \ 393 while (0) 394 #endif 395 396 /* This is how to declare the size of a cold function partition. */ 397 #ifndef ASM_DECLARE_COLD_FUNCTION_SIZE 398 #define ASM_DECLARE_COLD_FUNCTION_SIZE(FILE, FNAME, DECL) \ 399 do \ 400 { \ 401 if (!flag_inhibit_size_directive) \ 402 ASM_OUTPUT_MEASURED_SIZE (FILE, FNAME); \ 403 } \ 404 while (0) 405 #endif 406 407 /* A table of bytes codes used by the ASM_OUTPUT_ASCII and 408 ASM_OUTPUT_LIMITED_STRING macros. Each byte in the table 409 corresponds to a particular byte value [0..255]. For any 410 given byte value, if the value in the corresponding table 411 position is zero, the given character can be output directly. 412 If the table value is 1, the byte must be output as a \ooo 413 octal escape. If the tables value is anything else, then the 414 byte value should be output as a \ followed by the value 415 in the table. Note that we can use standard UN*X escape 416 sequences for many control characters, but we don't use 417 \a to represent BEL because some svr4 assemblers (e.g. on 418 the i386) don't know about that. Also, we don't use \v 419 since some versions of gas, such as 2.2 did not accept it. */ 420 421 #define ELF_ASCII_ESCAPES \ 422 "\1\1\1\1\1\1\1\1btn\1fr\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\ 423 \0\0\"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ 424 \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\\\0\0\0\ 425 \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1\ 426 \1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\ 427 \1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\ 428 \1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\ 429 \1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1" 430 431 /* Some svr4 assemblers have a limit on the number of characters which 432 can appear in the operand of a .string directive. If your assembler 433 has such a limitation, you should define STRING_LIMIT to reflect that 434 limit. Note that at least some svr4 assemblers have a limit on the 435 actual number of bytes in the double-quoted string, and that they 436 count each character in an escape sequence as one byte. Thus, an 437 escape sequence like \377 would count as four bytes. 438 439 If your target assembler doesn't support the .string directive, you 440 should define this to zero. 441 */ 442 443 #define ELF_STRING_LIMIT ((unsigned) 256) 444 445 #define STRING_ASM_OP "\t.string\t" 446 447 /* The routine used to output NUL terminated strings. We use a special 448 version of this for most svr4 targets because doing so makes the 449 generated assembly code more compact (and thus faster to assemble) 450 as well as more readable, especially for targets like the i386 451 (where the only alternative is to output character sequences as 452 comma separated lists of numbers). */ 453 454 #define ASM_OUTPUT_LIMITED_STRING(FILE, STR) \ 455 default_elf_asm_output_limited_string ((FILE), (STR)) 456 457 /* The routine used to output sequences of byte values. We use a special 458 version of this for most svr4 targets because doing so makes the 459 generated assembly code more compact (and thus faster to assemble) 460 as well as more readable. Note that if we find subparts of the 461 character sequence which end with NUL (and which are shorter than 462 STRING_LIMIT) we output those using ASM_OUTPUT_LIMITED_STRING. */ 463 464 #undef ASM_OUTPUT_ASCII 465 #define ASM_OUTPUT_ASCII(FILE, STR, LENGTH) \ 466 default_elf_asm_output_ascii ((FILE), (STR), (LENGTH)) 467 468 /* Allow the use of the -frecord-gcc-switches switch via the 469 elf_record_gcc_switches function defined in varasm.cc. */ 470 #undef TARGET_ASM_RECORD_GCC_SWITCHES 471 #define TARGET_ASM_RECORD_GCC_SWITCHES elf_record_gcc_switches 472 473 /* A C statement (sans semicolon) to output to the stdio stream STREAM 474 any text necessary for declaring the name of an external symbol 475 named NAME which is referenced in this compilation but not defined. 476 It is needed to properly support non-default visibility. */ 477 478 #ifndef ASM_OUTPUT_EXTERNAL 479 #define ASM_OUTPUT_EXTERNAL(FILE, DECL, NAME) \ 480 default_elf_asm_output_external (FILE, DECL, NAME) 481 #endif 482 483 #undef TARGET_LIBC_HAS_FUNCTION 484 #define TARGET_LIBC_HAS_FUNCTION no_c99_libc_has_function 485 486 /* ELF support needed only by D front-end. */ 487 488 #define TARGET_D_MINFO_SECTION "minfo" 489 #define TARGET_D_MINFO_START_NAME "__start_minfo" 490 #define TARGET_D_MINFO_END_NAME "__stop_minfo" 491