gcc/target.h

   1 /* Data structure definitions for a generic GCC target.
   2    Copyright (C) 2001-2024 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 /* These are defined in tree-vect-stmts.cc.  */
 169 extern tree stmt_vectype (class _stmt_vec_info *);
 170 extern bool stmt_in_inner_loop_p (class vec_info *, class _stmt_vec_info *);
 171
 172 /* Assembler instructions for creating various kinds of integer object.  */
 173
 174 struct asm_int_op
 175 {
 176   const char *hi;
 177   const char *psi;
 178   const char *si;
 179   const char *pdi;
 180   const char *di;
 181   const char *pti;
 182   const char *ti;
 183 };
 184
 185 /* Types of costs for vectorizer cost model.  */
 186 enum vect_cost_for_stmt
 187 {
 188   scalar_stmt,
 189   scalar_load,
 190   scalar_store,
 191   vector_stmt,
 192   vector_load,
 193   vector_gather_load,
 194   unaligned_load,
 195   unaligned_store,
 196   vector_store,
 197   vector_scatter_store,
 198   vec_to_scalar,
 199   scalar_to_vec,
 200   cond_branch_not_taken,
 201   cond_branch_taken,
 202   vec_perm,
 203   vec_promote_demote,
 204   vec_construct
 205 };
 206
 207 /* Separate locations for which the vectorizer cost model should
 208    track costs.  */
 209 enum vect_cost_model_location {
 210   vect_prologue = 0,
 211   vect_body = 1,
 212   vect_epilogue = 2
 213 };
 214
 215 class vec_perm_indices;
 216
 217 /* The type to use for lists of vector sizes.  */
 218 typedef vec<machine_mode> vector_modes;
 219
 220 /* Same, but can be used to construct local lists that are
 221    automatically freed.  */
 222 typedef auto_vec<machine_mode, 8> auto_vector_modes;
 223
 224 /* First argument of targetm.omp.device_kind_arch_isa.  */
 225 enum omp_device_kind_arch_isa {
 226   omp_device_kind,
 227   omp_device_arch,
 228   omp_device_isa
 229 };
 230
 231 /* Flags returned by TARGET_VECTORIZE_AUTOVECTORIZE_VECTOR_MODES:
 232
 233    VECT_COMPARE_COSTS
 234        Tells the loop vectorizer to try all the provided modes and
 235        pick the one with the lowest cost.  By default the vectorizer
 236        will choose the first mode that works.  */
 237 const unsigned int VECT_COMPARE_COSTS = 1U << 0;
 238
 239 /* The contexts in which the use of a type T can be checked by
 240    TARGET_VERIFY_TYPE_CONTEXT.  */
 241 enum type_context_kind {
 242   /* Directly measuring the size of T.  */
 243   TCTX_SIZEOF,
 244
 245   /* Directly measuring the alignment of T.  */
 246   TCTX_ALIGNOF,
 247
 248   /* Creating objects of type T with static storage duration.  */
 249   TCTX_STATIC_STORAGE,
 250
 251   /* Creating objects of type T with thread-local storage duration.  */
 252   TCTX_THREAD_STORAGE,
 253
 254   /* Creating a field of type T.  */
 255   TCTX_FIELD,
 256
 257   /* Creating an array with elements of type T.  */
 258   TCTX_ARRAY_ELEMENT,
 259
 260   /* Adding to or subtracting from a pointer to T, or computing the
 261      difference between two pointers when one of them is a pointer to T.  */
 262   TCTX_POINTER_ARITH,
 263
 264   /* Dynamically allocating objects of type T.  */
 265   TCTX_ALLOCATION,
 266
 267   /* Dynamically deallocating objects of type T.  */
 268   TCTX_DEALLOCATION,
 269
 270   /* Throwing or catching an object of type T.  */
 271   TCTX_EXCEPTIONS,
 272
 273   /* Capturing objects of type T by value in a closure.  */
 274   TCTX_CAPTURE_BY_COPY
 275 };
 276
 277 enum poly_value_estimate_kind
 278 {
 279   POLY_VALUE_MIN,
 280   POLY_VALUE_MAX,
 281   POLY_VALUE_LIKELY
 282 };
 283
 284 typedef void (*emit_support_tinfos_callback) (tree);
 285
 286 extern bool verify_type_context (location_t, type_context_kind, const_tree,
 287                                  bool = false);
 288
 289 /* The target structure.  This holds all the backend hooks.  */
 290 #define DEFHOOKPOD(NAME, DOC, TYPE, INIT) TYPE NAME;
 291 #define DEFHOOK(NAME, DOC, TYPE, PARAMS, INIT) TYPE (* NAME) PARAMS;
 292 #define DEFHOOK_UNDOC DEFHOOK
 293 #define HOOKSTRUCT(FRAGMENT) FRAGMENT
 294
 295 #include "target.def"
 296
 297 extern struct gcc_target targetm;
 298
 299 /* Return an estimate of the runtime value of X, for use in things
 300    like cost calculations or profiling frequencies.  Note that this
 301    function should never be used in situations where the actual
 302    runtime value is needed for correctness, since the function only
 303    provides a rough guess.  */
 304
 305 inline HOST_WIDE_INT
 306 estimated_poly_value (poly_int64 x,
 307                       poly_value_estimate_kind kind = POLY_VALUE_LIKELY)
 308 {
 309   if (NUM_POLY_INT_COEFFS == 1)
 310     return x.coeffs[0];
 311   else
 312     return targetm.estimated_poly_value (x, kind);
 313 }
 314
 315 #ifdef GCC_TM_H
 316
 317 #ifndef CUMULATIVE_ARGS_MAGIC
 318 #define CUMULATIVE_ARGS_MAGIC ((void *) &targetm.calls)
 319 #endif
 320
 321 inline CUMULATIVE_ARGS *
 322 get_cumulative_args (cumulative_args_t arg)
 323 {
 324 #if CHECKING_P
 325   gcc_assert (arg.magic == CUMULATIVE_ARGS_MAGIC);
 326 #endif /* CHECKING_P */
 327   return (CUMULATIVE_ARGS *) arg.p;
 328 }
 329
 330 inline cumulative_args_t
 331 pack_cumulative_args (CUMULATIVE_ARGS *arg)
 332 {
 333   cumulative_args_t ret;
 334
 335 #if CHECKING_P
 336   ret.magic = CUMULATIVE_ARGS_MAGIC;
 337 #endif /* CHECKING_P */
 338   ret.p = (void *) arg;
 339   return ret;
 340 }
 341 #endif /* GCC_TM_H */
 342
 343 #endif /* GCC_TARGET_H */