gcc/target.h

   1 /* Data structure definitions for a generic GCC target.
   2    Copyright (C) 2001-2025 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify it
   5    under the terms of the GNU General Public License as published by the
   6    Free Software Foundation; either version 3, or (at your option) any
   7    later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; see the file COPYING3.  If not see
  16    <http://www.gnu.org/licenses/>.
  17
  18    In other words, you are welcome to use, share and improve this program.
  19    You are forbidden to forbid anyone else to use, share and improve
  20    what you give them.   Help stamp out software-hoarding!  */
  21
  22
  23 /* This file contains a data structure that describes a GCC target.
  24    At present it is incomplete, but in future it should grow to
  25    contain most or all target machine and target O/S specific
  26    information.
  27
  28    This structure has its initializer declared in target-def.h in the
  29    form of large macro TARGET_INITIALIZER that expands to many smaller
  30    macros.
  31
  32    The smaller macros each initialize one component of the structure,
  33    and each has a default.  Each target should have a file that
  34    includes target.h and target-def.h, and overrides any inappropriate
  35    defaults by undefining the relevant macro and defining a suitable
  36    replacement.  That file should then contain the definition of
  37    "targetm" like so:
  38
  39    struct gcc_target targetm = TARGET_INITIALIZER;
  40
  41    Doing things this way allows us to bring together everything that
  42    defines a GCC target.  By supplying a default that is appropriate
  43    to most targets, we can easily add new items without needing to
  44    edit dozens of target configuration files.  It should also allow us
  45    to gradually reduce the amount of conditional compilation that is
  46    scattered throughout GCC.  */
  47
  48 #ifndef GCC_TARGET_H
  49 #define GCC_TARGET_H
  50
  51 #include "insn-codes.h"
  52 #include "tm.h"
  53 #include "hard-reg-set.h"
  54
  55 #if CHECKING_P
  56
  57 struct cumulative_args_t { void *magic; void *p; };
  58
  59 #else /* !CHECKING_P */
  60
  61 /* When using a GCC build compiler, we could use
  62    __attribute__((transparent_union)) to get cumulative_args_t function
  63    arguments passed like scalars where the ABI would mandate a less
  64    efficient way of argument passing otherwise.  However, that would come
  65    at the cost of less type-safe !CHECKING_P compilation.  */
  66
  67 union cumulative_args_t { void *p; };
  68
  69 #endif /* !CHECKING_P */
  70
  71 /* Target properties of _BitInt(N) type.  _BitInt(N) is to be represented
  72    as series of abi_limb_mode CEIL (N, GET_MODE_PRECISION (abi_limb_mode))
  73    limbs, ordered from least significant to most significant if !big_endian,
  74    otherwise from most significant to least significant.  If extended is
  75    false, the bits above or equal to N are undefined when stored in a register
  76    or memory, otherwise they are zero or sign extended depending on if
  77    it is unsigned _BitInt(N) or _BitInt(N) / signed _BitInt(N).
  78    limb_mode is either the same as abi_limb_mode, or some narrower mode
  79    in which _BitInt lowering should actually perform operations in and
  80    what libgcc _BitInt helpers should use.
  81    E.g. abi_limb_mode could be TImode which is something some processor
  82    specific ABI would specify to use, but it would be desirable to handle
  83    it as an array of DImode instead for efficiency.
  84    Note, abi_limb_mode can be different from limb_mode only if big_endian
  85    matches WORDS_BIG_ENDIAN.  */
  86
  87 struct bitint_info {
  88   machine_mode abi_limb_mode, limb_mode;
  89   bool big_endian;
  90   bool extended;
  91 };
  92
  93 /* Types of memory operation understood by the "by_pieces" infrastructure.
  94    Used by the TARGET_USE_BY_PIECES_INFRASTRUCTURE_P target hook and
  95    internally by the functions in expr.cc.  */
  96
  97 enum by_pieces_operation
  98 {
  99   CLEAR_BY_PIECES,
 100   MOVE_BY_PIECES,
 101   SET_BY_PIECES,
 102   STORE_BY_PIECES,
 103   COMPARE_BY_PIECES
 104 };
 105
 106 extern unsigned HOST_WIDE_INT by_pieces_ninsns (unsigned HOST_WIDE_INT,
 107                                                 unsigned int,
 108                                                 unsigned int,
 109                                                 by_pieces_operation);
 110
 111 /* An example implementation for ELF targets.  Defined in varasm.cc  */
 112 extern void elf_record_gcc_switches (const char *);
 113
 114 /* Some places still assume that all pointer or address modes are the
 115    standard Pmode and ptr_mode.  These optimizations become invalid if
 116    the target actually supports multiple different modes.  For now,
 117    we disable such optimizations on such targets, using this function.  */
 118 extern bool target_default_pointer_address_modes_p (void);
 119
 120 /* For hooks which use the MOVE_RATIO macro, this gives the legacy default
 121    behavior.  */
 122 extern unsigned int get_move_ratio (bool);
 123
 124 struct stdarg_info;
 125 struct spec_info_def;
 126 struct hard_reg_set_container;
 127 struct cgraph_node;
 128 struct cgraph_simd_clone;
 129
 130 /* The struct used by the secondary_reload target hook.  */
 131 struct secondary_reload_info
 132 {
 133   /* icode is actually an enum insn_code, but we don't want to force every
 134      file that includes target.h to include optabs.h .  */
 135   int icode;
 136   int extra_cost; /* Cost for using (a) scratch register(s) to be taken
 137                      into account by copy_cost.  */
 138   /* The next two members are for the use of the backward
 139      compatibility hook.  */
 140   struct secondary_reload_info *prev_sri;
 141   int t_icode; /* Actually an enum insn_code - see above.  */
 142 };
 143
 144 /* This is defined in sched-int.h .  */
 145 struct _dep;
 146
 147 /* This is defined in ddg.h .  */
 148 struct ddg;
 149
 150 /* This is defined in cfgloop.h .  */
 151 class loop;
 152
 153 /* This is defined in ifcvt.h.  */
 154 struct noce_if_info;
 155
 156 /* This is defined in tree-ssa-alias.h.  */
 157 class ao_ref;
 158
 159 /* This is defined in tree-vectorizer.h.  */
 160 class _stmt_vec_info;
 161
 162 /* This is defined in calls.h.  */
 163 class function_arg_info;
 164
 165 /* This is defined in function-abi.h.  */
 166 class predefined_function_abi;
 167
 168 /* This is defined in avoid-store-forwarding.h.  */
 169 struct store_fwd_info;
 170
 171 /* These are defined in tree-vect-stmts.cc.  */
 172 extern tree stmt_vectype (class _stmt_vec_info *);
 173 extern bool stmt_in_inner_loop_p (class vec_info *, class _stmt_vec_info *);
 174
 175 /* Assembler instructions for creating various kinds of integer object.  */
 176
 177 struct asm_int_op
 178 {
 179   const char *hi;
 180   const char *psi;
 181   const char *si;
 182   const char *pdi;
 183   const char *di;
 184   const char *pti;
 185   const char *ti;
 186 };
 187
 188 /* Types of costs for vectorizer cost model.  */
 189 enum vect_cost_for_stmt
 190 {
 191   scalar_stmt,
 192   scalar_load,
 193   scalar_store,
 194   vector_stmt,
 195   vector_load,
 196   vector_gather_load,
 197   unaligned_load,
 198   unaligned_store,
 199   vector_store,
 200   vector_scatter_store,
 201   vec_to_scalar,
 202   scalar_to_vec,
 203   cond_branch_not_taken,
 204   cond_branch_taken,
 205   vec_perm,
 206   vec_promote_demote,
 207   vec_construct
 208 };
 209
 210 /* Separate locations for which the vectorizer cost model should
 211    track costs.  */
 212 enum vect_cost_model_location {
 213   vect_prologue = 0,
 214   vect_body = 1,
 215   vect_epilogue = 2
 216 };
 217
 218 class vec_perm_indices;
 219
 220 /* The type to use for lists of vector sizes.  */
 221 typedef vec<machine_mode> vector_modes;
 222
 223 /* Same, but can be used to construct local lists that are
 224    automatically freed.  */
 225 typedef auto_vec<machine_mode, 8> auto_vector_modes;
 226
 227 /* First argument of targetm.omp.device_kind_arch_isa.  */
 228 enum omp_device_kind_arch_isa {
 229   omp_device_kind,
 230   omp_device_arch,
 231   omp_device_isa
 232 };
 233
 234 /* Flags returned by TARGET_VECTORIZE_AUTOVECTORIZE_VECTOR_MODES:
 235
 236    VECT_COMPARE_COSTS
 237        Tells the loop vectorizer to try all the provided modes and
 238        pick the one with the lowest cost.  By default the vectorizer
 239        will choose the first mode that works.  */
 240 const unsigned int VECT_COMPARE_COSTS = 1U << 0;
 241
 242 /* The contexts in which the use of a type T can be checked by
 243    TARGET_VERIFY_TYPE_CONTEXT.  */
 244 enum type_context_kind {
 245   /* Directly measuring the size of T.  */
 246   TCTX_SIZEOF,
 247
 248   /* Directly measuring the alignment of T.  */
 249   TCTX_ALIGNOF,
 250
 251   /* Creating objects of type T with static storage duration.  */
 252   TCTX_STATIC_STORAGE,
 253
 254   /* Creating objects of type T with thread-local storage duration.  */
 255   TCTX_THREAD_STORAGE,
 256
 257   /* Creating a field of type T.  */
 258   TCTX_FIELD,
 259
 260   /* Creating an array with elements of type T.  */
 261   TCTX_ARRAY_ELEMENT,
 262
 263   /* Adding to or subtracting from a pointer to T, or computing the
 264      difference between two pointers when one of them is a pointer to T.  */
 265   TCTX_POINTER_ARITH,
 266
 267   /* Dynamically allocating objects of type T.  */
 268   TCTX_ALLOCATION,
 269
 270   /* Dynamically deallocating objects of type T.  */
 271   TCTX_DEALLOCATION,
 272
 273   /* Throwing or catching an object of type T.  */
 274   TCTX_EXCEPTIONS,
 275
 276   /* Capturing objects of type T by value in a closure.  */
 277   TCTX_CAPTURE_BY_COPY
 278 };
 279
 280 enum poly_value_estimate_kind
 281 {
 282   POLY_VALUE_MIN,
 283   POLY_VALUE_MAX,
 284   POLY_VALUE_LIKELY
 285 };
 286
 287 typedef void (*emit_support_tinfos_callback) (tree);
 288
 289 extern bool verify_type_context (location_t, type_context_kind, const_tree,
 290                                  bool = false);
 291
 292 /* The target structure.  This holds all the backend hooks.  */
 293 #define DEFHOOKPOD(NAME, DOC, TYPE, INIT) TYPE NAME;
 294 #define DEFHOOK(NAME, DOC, TYPE, PARAMS, INIT) TYPE (* NAME) PARAMS;
 295 #define DEFHOOK_UNDOC DEFHOOK
 296 #define HOOKSTRUCT(FRAGMENT) FRAGMENT
 297
 298 #include "target.def"
 299
 300 extern struct gcc_target targetm;
 301
 302 /* Return an estimate of the runtime value of X, for use in things
 303    like cost calculations or profiling frequencies.  Note that this
 304    function should never be used in situations where the actual
 305    runtime value is needed for correctness, since the function only
 306    provides a rough guess.  */
 307
 308 inline HOST_WIDE_INT
 309 estimated_poly_value (poly_int64 x,
 310                       poly_value_estimate_kind kind = POLY_VALUE_LIKELY)
 311 {
 312   if (NUM_POLY_INT_COEFFS == 1)
 313     return x.coeffs[0];
 314   else
 315     return targetm.estimated_poly_value (x, kind);
 316 }
 317
 318 /* Return true when MODE can be used to copy GET_MODE_BITSIZE bits
 319    unchanged.  */
 320
 321 inline bool
 322 mode_can_transfer_bits (machine_mode mode)
 323 {
 324   if (mode == BLKmode)
 325     return true;
 326   if (maybe_ne (GET_MODE_BITSIZE (mode),
 327                 GET_MODE_UNIT_PRECISION (mode) * GET_MODE_NUNITS (mode)))
 328     return false;
 329   if (targetm.mode_can_transfer_bits)
 330     return targetm.mode_can_transfer_bits (mode);
 331   return true;
 332 }
 333
 334 #ifdef GCC_TM_H
 335
 336 #ifndef CUMULATIVE_ARGS_MAGIC
 337 #define CUMULATIVE_ARGS_MAGIC ((void *) &targetm.calls)
 338 #endif
 339
 340 inline CUMULATIVE_ARGS *
 341 get_cumulative_args (cumulative_args_t arg)
 342 {
 343 #if CHECKING_P
 344   gcc_assert (arg.magic == CUMULATIVE_ARGS_MAGIC);
 345 #endif /* CHECKING_P */
 346   return (CUMULATIVE_ARGS *) arg.p;
 347 }
 348
 349 inline cumulative_args_t
 350 pack_cumulative_args (CUMULATIVE_ARGS *arg)
 351 {
 352   cumulative_args_t ret;
 353
 354 #if CHECKING_P
 355   ret.magic = CUMULATIVE_ARGS_MAGIC;
 356 #endif /* CHECKING_P */
 357   ret.p = (void *) arg;
 358   return ret;
 359 }
 360 #endif /* GCC_TM_H */
 361
 362 #endif /* GCC_TARGET_H */