gcc/config/rs6000/darwin.h

   1 /* Target definitions for PowerPC running Darwin (Mac OS X).
   2    Copyright (C) 1997-2023 Free Software Foundation, Inc.
   3    Contributed by Apple Computer Inc.
   4
   5    This file is part of GCC.
   6
   7    GCC is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published
   9    by the Free Software Foundation; either version 3, or (at your
  10    option) any later version.
  11
  12    GCC is distributed in the hope that it will be useful, but WITHOUT
  13    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  15    License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GCC; see the file COPYING3.  If not see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #undef DARWIN_PPC
  22 #define DARWIN_PPC 1
  23
  24 /* The "Darwin ABI" is mostly like AIX, but with some key differences.  */
  25
  26 #define DEFAULT_ABI ABI_DARWIN
  27
  28 #ifdef IN_LIBGCC2
  29 #undef TARGET_64BIT
  30 #ifdef __powerpc64__
  31 #define TARGET_64BIT 1
  32 #else
  33 #define TARGET_64BIT 0
  34 #endif
  35 #endif
  36
  37 /* The object file format is Mach-O.  */
  38
  39 #define TARGET_OBJECT_FORMAT OBJECT_MACHO
  40
  41 /* Size of the Obj-C jump buffer.  */
  42 #define OBJC_JBLEN ((TARGET_64BIT) ? (26*2 + 18*2 + 129 + 1) : (26 + 18*2 + 129 + 1))
  43
  44 /* We're not ever going to do TOCs.  */
  45
  46 #define TARGET_HAS_TOC 0
  47
  48 /* Override the default rs6000 definition.  */
  49 #undef  PTRDIFF_TYPE
  50 #define PTRDIFF_TYPE (TARGET_64BIT ? "long int" : "int")
  51
  52 #define TARGET_OS_CPP_BUILTINS()                        \
  53   do                                                    \
  54     {                                                   \
  55       builtin_define ("__POWERPC__");                   \
  56       builtin_define ("__PPC__");                       \
  57       if (TARGET_64BIT)                                 \
  58         {                                               \
  59           builtin_define ("__ppc64__");                 \
  60           builtin_define ("__PPC64__");                 \
  61           builtin_define ("__powerpc64__");             \
  62           builtin_assert ("cpu=powerpc64");             \
  63           builtin_assert ("machine=powerpc64");         \
  64         }                                               \
  65       else                                              \
  66         {                                               \
  67           builtin_define ("__ppc__");                   \
  68           builtin_define_std ("PPC");                   \
  69           builtin_assert ("cpu=powerpc");               \
  70           builtin_assert ("machine=powerpc");           \
  71         }                                               \
  72       builtin_define ("__NATURAL_ALIGNMENT__");         \
  73       darwin_cpp_builtins (pfile);                      \
  74     }                                                   \
  75   while (0)
  76
  77 #define SUBTARGET_OVERRIDE_OPTIONS darwin_rs6000_override_options ()
  78
  79 #define C_COMMON_OVERRIDE_OPTIONS do {                                  \
  80   /* On powerpc, __cxa_get_exception_ptr is available starting in the   \
  81      10.4.6 libstdc++.dylib.  */                                        \
  82   if (strverscmp (darwin_macosx_version_min, "10.4.6") < 0              \
  83       && flag_use_cxa_get_exception_ptr == 2)                           \
  84     flag_use_cxa_get_exception_ptr = 0;                                 \
  85   if (flag_mkernel)                                                     \
  86     flag_no_builtin = 1;                                                \
  87   SUBTARGET_C_COMMON_OVERRIDE_OPTIONS;                                  \
  88 } while (0)
  89
  90 /* Darwin has 128-bit long double support in libc in 10.4 and later.
  91    Default to 128-bit long doubles even on earlier platforms for ABI
  92    consistency; arithmetic will work even if libc and libm support is
  93    not available.  */
  94
  95 #define RS6000_DEFAULT_LONG_DOUBLE_SIZE 128
  96
  97 /* Machine dependent libraries.
  98    Include libmx when targeting Darwin 7.0 and above, but before libSystem,
  99    since the functions are actually in libSystem but for 7.x compatibility
 100    we want them to be looked for in libmx first.
 101    Include libSystemStubs when compiling against 10.3 - 10.6 SDKs (we assume
 102    this is the case when targetting these) - but not for 64-bit long double.
 103    Don't do either for m64, the library is either a dummy or non-existent.
 104 */
 105
 106 #undef LIB_SPEC
 107 #define LIB_SPEC \
 108 "%{!static:                                                             \
 109   %{!m64:%{!mlong-double-64:                                            \
 110     %{pg:%:version-compare(>< 10.3 10.7 mmacosx-version-min= -lSystemStubs_profile)} \
 111     %{!pg:%:version-compare(>< 10.3 10.7 mmacosx-version-min= -lSystemStubs)} \
 112      %:version-compare(>< 10.3 10.4 mmacosx-version-min= -lmx)}}        \
 113   -lSystem                                                              \
 114 }"
 115
 116 /* We want -fPIC by default, unless we're using -static to compile for
 117    the kernel or some such.  The "-faltivec" option should have been
 118    called "-maltivec" all along.  */
 119
 120 #define CC1_SPEC "\
 121   %(cc1_cpu) \
 122   %{g: %{!fno-eliminate-unused-debug-symbols: -feliminate-unused-debug-symbols }} \
 123   %{static: %{Zdynamic: %e conflicting code gen style switches are used}}\
 124   %{!mkernel:%{!static:%{!mdynamic-no-pic:-fPIC}}} \
 125   %{faltivec:-maltivec -include altivec.h} %{fno-altivec:-mno-altivec} \
 126   %<faltivec %<fno-altivec " \
 127   DARWIN_CC1_SPEC
 128
 129 /* Default to PPC for single arch builds.  */
 130 #define DARWIN_ARCH_SPEC "ppc"
 131
 132 #define DARWIN_SUBARCH_SPEC "                   \
 133  %{mcpu=601:ppc601;                             \
 134    mcpu=603:ppc603;                             \
 135    mcpu=603e:ppc603;                            \
 136    mcpu=604:ppc604;                             \
 137    mcpu=604e:ppc604e;                           \
 138    mcpu=740:ppc750;                             \
 139    mcpu=750:ppc750;                             \
 140    mcpu=G3:ppc750;                              \
 141    mcpu=7400:ppc7400;                           \
 142    mcpu=G4:ppc7400;                             \
 143    mcpu=7450:ppc7450;                           \
 144    mcpu=970:ppc970;                             \
 145    mcpu=power4:ppc970;                          \
 146    mcpu=G5:ppc970;                              \
 147    :ppc}"
 148
 149 /* We need to jam the crt to 10.5 for 10.6 (Rosetta) use.  */
 150 #undef DARWIN_CRT1_SPEC
 151 #define DARWIN_CRT1_SPEC                                                \
 152   "%:version-compare(!> 10.5 mmacosx-version-min= -lcrt1.o)             \
 153    %:version-compare(>< 10.5 10.7 mmacosx-version-min= -lcrt1.10.5.o)   \
 154    %{fgnu-tm: -lcrttms.o}"
 155
 156 /* crt2.o is at least partially required for 10.3.x and earlier.
 157    It deals with registration of the unwind frames, where this is not
 158    automatically provided by the system.  So we need it for any case that
 159    might use exceptions.  */
 160 #undef DARWIN_CRT2_SPEC
 161 #define DARWIN_CRT2_SPEC \
 162 "%{!m64:%{shared-libgcc|static-libstdc++|fexceptions|fobjc-exceptions|fgnu-runtime: \
 163    %:version-compare(!> 10.4 mmacosx-version-min= crt2.o%s) \
 164   }}"
 165
 166 /* crt3 deals with providing cxa_atexit on earlier systems (or fixing it up,
 167    for broken versions).  It's only needed for c++ code, so we can make it
 168    conditional on shared-libgcc since that's forced on for c++.  */
 169 #undef DARWIN_CRT3_SPEC
 170 #define DARWIN_CRT3_SPEC \
 171 "%{!m64:%{shared-libgcc|static-libstdc++:                                                       \
 172    %:version-compare(>< 10.4 10.5 mmacosx-version-min= crt3.o%s) \
 173    %:version-compare(!> 10.4 mmacosx-version-min= crt3_2.o%s) \
 174   }}"
 175
 176 /* As for crt1, we need to force the dylib crt for 10.6.  */
 177 #undef DARWIN_DYLIB1_SPEC
 178 #define DARWIN_DYLIB1_SPEC                                              \
 179   "%:version-compare(!> 10.5 mmacosx-version-min= -ldylib1.o)           \
 180    %:version-compare(>< 10.5 10.7 mmacosx-version-min= -ldylib1.10.5.o)"
 181
 182 /* Likewise, the bundle crt.  */
 183 #undef DARWIN_BUNDLE1_SPEC
 184 #define DARWIN_BUNDLE1_SPEC \
 185 "%{!static:%:version-compare(< 10.7 mmacosx-version-min= -lbundle1.o)   \
 186            %{fgnu-tm: -lcrttms.o}}"
 187
 188 /* The PPC regs save/restore functions are leaves and could, conceivably
 189    be used by the tm destructor.  */
 190 #undef ENDFILE_SPEC
 191 #define ENDFILE_SPEC TM_DESTRUCTOR " -lef_ppc"
 192
 193 #undef SUBTARGET_EXTRA_SPECS
 194 #define SUBTARGET_EXTRA_SPECS                   \
 195   DARWIN_EXTRA_SPECS                            \
 196   { "darwin_arch", DARWIN_ARCH_SPEC },          \
 197   { "darwin_crt2", DARWIN_CRT2_SPEC },          \
 198   { "darwin_subarch", DARWIN_SUBARCH_SPEC },
 199
 200 /* Output a .machine directive.  */
 201 #undef TARGET_ASM_FILE_START
 202 #define TARGET_ASM_FILE_START rs6000_darwin_file_start
 203
 204 /* Make both r2 and r13 available for allocation.  */
 205 #define FIXED_R2 0
 206 #define FIXED_R13 TARGET_64BIT
 207
 208 /* Base register for access to local variables of the function.  */
 209
 210 #undef  HARD_FRAME_POINTER_REGNUM
 211 #define HARD_FRAME_POINTER_REGNUM 30
 212
 213 #undef  RS6000_PIC_OFFSET_TABLE_REGNUM
 214 #define RS6000_PIC_OFFSET_TABLE_REGNUM 31
 215
 216 #undef FIRST_SAVED_GP_REGNO
 217 #define FIRST_SAVED_GP_REGNO 13
 218
 219 /* Darwin's stack must remain 16-byte aligned for both 32 and 64 bit
 220    ABIs.  */
 221
 222 #undef  STACK_BOUNDARY
 223 #define STACK_BOUNDARY 128
 224
 225 /* Offset within stack frame to start allocating local variables at.
 226    For supported Darwin versions, FRAME_GROWS_DOWNWARD is true, therefore
 227    this value is the offset to the END of the first local allocated.
 228
 229    On the RS/6000, the frame pointer is the same as the stack pointer,
 230    except for dynamic allocations.  So we start after the fixed area and
 231    outgoing parameter area.
 232
 233    If the function uses dynamic stack space (CALLS_ALLOCA is set), that
 234    space needs to be aligned to STACK_BOUNDARY, i.e. the sum of the
 235    sizes of the fixed area and the parameter area must be a multiple of
 236    STACK_BOUNDARY.  */
 237
 238 #undef RS6000_STARTING_FRAME_OFFSET
 239 #define RS6000_STARTING_FRAME_OFFSET                                    \
 240   (cfun->calls_alloca                                                   \
 241    ? RS6000_ALIGN (crtl->outgoing_args_size + RS6000_SAVE_AREA, 16)     \
 242    : (RS6000_ALIGN (crtl->outgoing_args_size, 16) + RS6000_SAVE_AREA))
 243
 244 /* Offset from the stack pointer register to an item dynamically
 245    allocated on the stack, e.g., by `alloca'.
 246
 247    The default value for this macro is `STACK_POINTER_OFFSET' plus the
 248    length of the outgoing arguments.  The default is correct for most
 249    machines.  See `function.cc' for details.
 250
 251    This value must be a multiple of STACK_BOUNDARY (hard coded in
 252    `emit-rtl.cc').  */
 253
 254 #undef STACK_DYNAMIC_OFFSET
 255 #define STACK_DYNAMIC_OFFSET(FUNDECL)                                   \
 256   RS6000_ALIGN (crtl->outgoing_args_size.to_constant()                  \
 257                 + STACK_POINTER_OFFSET, 16)
 258
 259 /* Darwin uses a function call if everything needs to be saved/restored.  */
 260
 261 #undef WORLD_SAVE_P
 262 #define WORLD_SAVE_P(INFO) ((INFO)->world_save_p)
 263
 264 /* We don't use these on Darwin, they are just place-holders.  */
 265 #define SAVE_FP_PREFIX ""
 266 #define SAVE_FP_SUFFIX ""
 267 #define RESTORE_FP_PREFIX ""
 268 #define RESTORE_FP_SUFFIX ""
 269
 270 /* The assembler wants the alternate register names, but without
 271    leading percent sign.  */
 272 #undef REGISTER_NAMES
 273 #define REGISTER_NAMES                                                  \
 274 {                                                                       \
 275   /* GPRs */                                                            \
 276      "r0",  "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",             \
 277      "r8",  "r9", "r10", "r11", "r12", "r13", "r14", "r15",             \
 278     "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",             \
 279     "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",             \
 280   /* FPRs */                                                            \
 281      "f0",  "f1",  "f2",  "f3",  "f4",  "f5",  "f6",  "f7",             \
 282      "f8",  "f9", "f10", "f11", "f12", "f13", "f14", "f15",             \
 283     "f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23",             \
 284     "f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31",             \
 285   /* VRs */                                                             \
 286      "v0",  "v1",  "v2",  "v3",  "v4",  "v5",  "v6",  "v7",             \
 287      "v8",  "v9", "v10", "v11", "v12", "v13", "v14", "v15",             \
 288     "v16", "v17", "v18", "v19", "v20", "v21", "v22", "v23",             \
 289     "v24", "v25", "v26", "v27", "v28", "v29", "v30", "v31",             \
 290   /* lr ctr ca ap */                                                    \
 291      "lr", "ctr", "xer",  "ap",                                         \
 292   /* cr0..cr7 */                                                        \
 293     "cr0", "cr1", "cr2", "cr3", "cr4", "cr5", "cr6", "cr7",             \
 294   /* vrsave vscr sfp */                                                 \
 295     "vrsave", "vscr", "sfp"                                             \
 296 }
 297
 298 /* This outputs NAME to FILE.  */
 299
 300 #undef  RS6000_OUTPUT_BASENAME
 301 #define RS6000_OUTPUT_BASENAME(FILE, NAME)      \
 302     assemble_name (FILE, NAME)
 303
 304 /* Globalizing directive for a label.  */
 305 #undef GLOBAL_ASM_OP
 306 #define GLOBAL_ASM_OP "\t.globl "
 307 #undef TARGET_ASM_GLOBALIZE_LABEL
 308
 309 /* This is how to output an internal label prefix.  rs6000.cc uses this
 310    when generating traceback tables.  */
 311 /* Not really used for Darwin?  */
 312
 313 #undef ASM_OUTPUT_INTERNAL_LABEL_PREFIX
 314 #define ASM_OUTPUT_INTERNAL_LABEL_PREFIX(FILE,PREFIX)   \
 315   fprintf (FILE, "%s", PREFIX)
 316
 317 /* Override the standard rs6000 definition.  */
 318
 319 #undef ASM_COMMENT_START
 320 #define ASM_COMMENT_START ";"
 321
 322 /* This is how to output an assembler line that says to advance
 323    the location counter to a multiple of 2**LOG bytes using the
 324    "nop" instruction as padding.  */
 325
 326 #define ASM_OUTPUT_ALIGN_WITH_NOP(FILE,LOG)                   \
 327   do                                                          \
 328     {                                                         \
 329       if ((LOG) < 3)                                          \
 330         {                                                     \
 331           ASM_OUTPUT_ALIGN (FILE,LOG);                        \
 332         }                                                     \
 333       else /* nop == ori r0,r0,0 */                           \
 334         fprintf (FILE, "\t.align32 %d,0x60000000\n", (LOG));  \
 335     } while (0)
 336
 337 #ifdef HAVE_GAS_MAX_SKIP_P2ALIGN
 338 /* This is supported in cctools 465 and later.  The macro test
 339    above prevents using it in earlier build environments.  */
 340 #define ASM_OUTPUT_MAX_SKIP_ALIGN(FILE,LOG,MAX_SKIP)          \
 341   if ((LOG) > 0)                                             \
 342     {                                                         \
 343       if ((MAX_SKIP) <= 0)                                    \
 344         fprintf ((FILE), "\t.p2align %d\n", (LOG));           \
 345       else                                                    \
 346         fprintf ((FILE), "\t.p2align %d,,%d\n", (LOG), (MAX_SKIP)); \
 347     }
 348 #endif
 349
 350 /* Generate insns to call the profiler.  */
 351
 352 #define PROFILE_HOOK(LABEL)   output_profile_hook (LABEL)
 353
 354 /* Function name to call to do profiling.  */
 355
 356 #define RS6000_MCOUNT "*mcount"
 357
 358 /* Default processor: G4, and G5 for 64-bit.  */
 359
 360 #undef PROCESSOR_DEFAULT
 361 #define PROCESSOR_DEFAULT  PROCESSOR_PPC7400
 362 #undef PROCESSOR_DEFAULT64
 363 #define PROCESSOR_DEFAULT64  PROCESSOR_POWER4
 364
 365 /* Default target flag settings.  Despite the fact that STMW/LMW
 366    serializes, it's still a big code size win to use them.  Use FSEL by
 367    default as well.  */
 368
 369 #undef  TARGET_DEFAULT
 370 #define TARGET_DEFAULT (OPTION_MASK_MULTIPLE | OPTION_MASK_PPC_GFXOPT)
 371
 372 /* Darwin always uses IBM long double, never IEEE long double.  */
 373 #undef  TARGET_IEEEQUAD
 374 #define TARGET_IEEEQUAD 0
 375
 376 #undef  TARGET_IEEEQUAD_DEFAULT
 377 #define TARGET_IEEEQUAD_DEFAULT 0
 378
 379 /* Since Darwin doesn't do TOCs, stub this out.  */
 380
 381 #define ASM_OUTPUT_SPECIAL_POOL_ENTRY_P(X, MODE)  ((void)X, (void)MODE, 0)
 382
 383 /* Unlike most other PowerPC targets, chars are signed, for
 384    consistency with other Darwin architectures.  */
 385
 386 #undef DEFAULT_SIGNED_CHAR
 387 #define DEFAULT_SIGNED_CHAR (1)
 388
 389 /* Given an rtx X being reloaded into a reg required to be
 390    in class CLASS, return the class of reg to actually use.
 391    In general this is just CLASS; but on some machines
 392    in some cases it is preferable to use a more restrictive class.
 393
 394    On the RS/6000, we have to return NO_REGS when we want to reload a
 395    floating-point CONST_DOUBLE to force it to be copied to memory.
 396
 397    Don't allow R0 when loading the address of, or otherwise furtling with,
 398    a SYMBOL_REF.  */
 399
 400 #undef PREFERRED_RELOAD_CLASS
 401 #define PREFERRED_RELOAD_CLASS(X,CLASS)                         \
 402   ((CONSTANT_P (X)                                              \
 403     && reg_classes_intersect_p ((CLASS), FLOAT_REGS))           \
 404    ? NO_REGS                                                    \
 405    : ((SYMBOL_REF_P (X) || GET_CODE (X) == HIGH)                \
 406       && reg_class_subset_p (BASE_REGS, (CLASS)))               \
 407    ? BASE_REGS                                                  \
 408    : (GET_MODE_CLASS (GET_MODE (X)) == MODE_INT                 \
 409       && (CLASS) == GEN_OR_FLOAT_REGS)                          \
 410    ? GENERAL_REGS                                               \
 411    : (CLASS))
 412
 413 /* Compute field alignment.
 414    This implements the 'power' alignment rule by pegging the alignment of
 415    items (beyond the first aggregate field) to 32 bits.  The pegging is
 416    suppressed for vector and long double items (both 128 in size).
 417    There is a dummy use of the FIELD argument to avoid an unused variable
 418    warning (see PR59496).  */
 419 #define ADJUST_FIELD_ALIGN(FIELD, TYPE, COMPUTED)               \
 420   ((void) (FIELD),                                              \
 421     (TARGET_ALIGN_NATURAL                                       \
 422      ? (COMPUTED)                                               \
 423      : (COMPUTED) == 128                                        \
 424         ? 128                                                   \
 425         : MIN ((COMPUTED), 32)))
 426
 427 /* Darwin increases natural record alignment to doubleword if the first
 428    field is an FP double while the FP fields remain word aligned.  */
 429 #define ROUND_TYPE_ALIGN(STRUCT, COMPUTED, SPECIFIED)                     \
 430   (RECORD_OR_UNION_TYPE_P (STRUCT)                                \
 431    && TARGET_ALIGN_NATURAL == 0                                           \
 432    ? darwin_rs6000_special_round_type_align (STRUCT, COMPUTED, SPECIFIED) \
 433    : (VECTOR_TYPE_P (STRUCT)                                      \
 434       && ALTIVEC_VECTOR_MODE (TYPE_MODE (STRUCT)))                        \
 435    ? MAX (MAX ((COMPUTED), (SPECIFIED)), 128)                             \
 436    : MAX ((COMPUTED), (SPECIFIED)))
 437
 438 /* Specify padding for the last element of a block move between
 439    registers and memory.  FIRST is nonzero if this is the only
 440    element.  */
 441 #define BLOCK_REG_PADDING(MODE, TYPE, FIRST) \
 442   (!(FIRST) ? PAD_UPWARD : targetm.calls.function_arg_padding (MODE, TYPE))
 443
 444 #define DOUBLE_INT_ASM_OP "\t.quad\t"
 445
 446 /* For binary compatibility with 2.95; Darwin C APIs use bool from
 447    stdbool.h, which was an int-sized enum in 2.95.  Users can explicitly
 448    choose to have sizeof(bool)==1 with the -mone-byte-bool switch. */
 449 #define BOOL_TYPE_SIZE (darwin_one_byte_bool ? CHAR_TYPE_SIZE : INT_TYPE_SIZE)
 450
 451 #undef REGISTER_TARGET_PRAGMAS
 452 #define REGISTER_TARGET_PRAGMAS() \
 453   do \
 454     { \
 455       DARWIN_REGISTER_TARGET_PRAGMAS(); \
 456       targetm.target_option.pragma_parse = rs6000_pragma_target_parse; \
 457       targetm.resolve_overloaded_builtin = altivec_resolve_overloaded_builtin; \
 458     } \
 459   while (0)
 460
 461 #ifdef IN_LIBGCC2
 462 #include <stdbool.h>
 463 #endif
 464
 465 /* True, iff we're generating fast turn around debugging code.  When
 466    true, we arrange for function prologues to start with 5 nops so
 467    that gdb may insert code to redirect them, and for data to be
 468    accessed indirectly.  The runtime uses this indirection to forward
 469    references for data to the original instance of that data.  */
 470
 471 #define TARGET_FIX_AND_CONTINUE (darwin_fix_and_continue)
 472
 473 /* This is the reserved direct dispatch address for Objective-C.  */
 474 #define OFFS_MSGSEND_FAST               0xFFFEFF00
 475
 476 /* This is the reserved ivar address Objective-C.  */
 477 #define OFFS_ASSIGNIVAR_FAST            0xFFFEFEC0
 478
 479 /* Old versions of Mac OS/Darwin don't have C99 functions available.  */
 480 #undef TARGET_LIBC_HAS_FUNCTION
 481 #define TARGET_LIBC_HAS_FUNCTION darwin_libc_has_function
 482
 483 /* When generating kernel code or kexts, we don't use Altivec by
 484    default, as kernel code doesn't save/restore those registers.  */
 485 #define OS_MISSING_ALTIVEC (flag_mkernel || flag_apple_kext)
 486
 487 /* Darwin has support for section anchors on powerpc*.
 488    It is disabled for any section containing a "zero-sized item" (because these
 489    are re-written as size=1 to be compatible with the OSX ld64).
 490    The re-writing would interfere with the computation of anchor offsets.
 491    Therefore, we place zero-sized items in their own sections and make such
 492    sections unavailable to section anchoring.  */
 493
 494 #undef TARGET_ASM_OUTPUT_ANCHOR
 495 #define TARGET_ASM_OUTPUT_ANCHOR darwin_asm_output_anchor
 496
 497 #undef TARGET_USE_ANCHORS_FOR_SYMBOL_P
 498 #define TARGET_USE_ANCHORS_FOR_SYMBOL_P darwin_use_anchors_for_symbol_p
 499
 500 #undef DARWIN_SECTION_ANCHORS
 501 #define DARWIN_SECTION_ANCHORS 1
 502
 503 /* PPC Darwin has to rename some of the long double builtins.  */
 504 #undef  SUBTARGET_INIT_BUILTINS
 505 #define SUBTARGET_INIT_BUILTINS                                         \
 506 do {                                                                    \
 507   darwin_patch_builtins ();                                             \
 508   rs6000_builtin_decls[(unsigned) (RS6000_BIF_CFSTRING)]                \
 509     = darwin_init_cfstring_builtins ((unsigned) (RS6000_BIF_CFSTRING)); \
 510 } while(0)
 511
 512 /* So far, there is no rs6000_fold_builtin, if one is introduced, then
 513    this will need to be modified similar to the x86 case.  */
 514 #define TARGET_FOLD_BUILTIN SUBTARGET_FOLD_BUILTIN
 515
 516 /* First available SYMBOL flag bit for use by subtargets.  */
 517 #define SYMBOL_FLAG_SUBT_DEP (SYMBOL_FLAG_MACH_DEP)
 518
 519 /* Use standard DWARF numbering for DWARF debugging information.  */
 520 #define RS6000_USE_DWARF_NUMBERING
 521