gcc/expr.h

   1 /* Definitions for code generation pass of GNU compiler.
   2    Copyright (C) 1987-2024 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef GCC_EXPR_H
  21 #define GCC_EXPR_H
  22
  23 /* This is the 4th arg to `expand_expr'.
  24    EXPAND_STACK_PARM means we are possibly expanding a call param onto
  25    the stack.
  26    EXPAND_SUM means it is ok to return a PLUS rtx or MULT rtx.
  27    EXPAND_INITIALIZER is similar but also record any labels on forced_labels.
  28    EXPAND_CONST_ADDRESS means it is ok to return a MEM whose address
  29     is a constant that is not a legitimate address.
  30    EXPAND_WRITE means we are only going to write to the resulting rtx.
  31    EXPAND_MEMORY means we are interested in a memory result, even if
  32     the memory is constant and we could have propagated a constant value,
  33     or the memory is unaligned on a STRICT_ALIGNMENT target.  */
  34 enum expand_modifier {EXPAND_NORMAL = 0, EXPAND_STACK_PARM, EXPAND_SUM,
  35                       EXPAND_CONST_ADDRESS, EXPAND_INITIALIZER, EXPAND_WRITE,
  36                       EXPAND_MEMORY};
  37
  38 /* Prevent the compiler from deferring stack pops.  See
  39    inhibit_defer_pop for more information.  */
  40 #define NO_DEFER_POP (inhibit_defer_pop += 1)
  41
  42 /* Allow the compiler to defer stack pops.  See inhibit_defer_pop for
  43    more information.  */
  44 #define OK_DEFER_POP (inhibit_defer_pop -= 1)
  45 \f
  46 /* This structure is used to pass around information about exploded
  47    unary, binary and trinary expressions between expand_expr_real_1 and
  48    friends.  */
  49 typedef struct separate_ops
  50 {
  51   enum tree_code code;
  52   location_t location;
  53   tree type;
  54   tree op0, op1, op2;
  55 } *sepops;
  56
  57 typedef const struct separate_ops *const_sepops;
  58 \f
  59 /* This is run during target initialization to set up which modes can be
  60    used directly in memory and to initialize the block move optab.  */
  61 extern void init_expr_target (void);
  62
  63 /* This is run at the start of compiling a function.  */
  64 extern void init_expr (void);
  65
  66 /* Emit some rtl insns to move data between rtx's, converting machine modes.
  67    Both modes must be floating or both fixed.  */
  68 extern void convert_move (rtx, rtx, int);
  69
  70 /* Convert an rtx to specified machine mode and return the result.  */
  71 extern rtx convert_to_mode (machine_mode, rtx, int);
  72
  73 /* Convert an rtx to MODE from OLDMODE and return the result.  */
  74 extern rtx convert_modes (machine_mode mode, machine_mode oldmode,
  75                           rtx x, int unsignedp);
  76
  77 /* Variant of convert_modes for ABI parameter passing/return.  */
  78 extern rtx convert_float_to_wider_int (machine_mode mode, machine_mode fmode,
  79                                        rtx x);
  80
  81 /* Variant of convert_modes for ABI parameter passing/return.  */
  82 extern rtx convert_wider_int_to_float (machine_mode mode, machine_mode imode,
  83                                        rtx x);
  84
  85 /* Expand a call to memcpy or memmove or memcmp, and return the result.  */
  86 extern rtx emit_block_op_via_libcall (enum built_in_function, rtx, rtx, rtx,
  87                                       bool);
  88
  89 inline rtx
  90 emit_block_copy_via_libcall (rtx dst, rtx src, rtx size, bool tailcall = false)
  91 {
  92   return emit_block_op_via_libcall (BUILT_IN_MEMCPY, dst, src, size, tailcall);
  93 }
  94
  95 inline rtx
  96 emit_block_move_via_libcall (rtx dst, rtx src, rtx size, bool tailcall = false)
  97 {
  98   return emit_block_op_via_libcall (BUILT_IN_MEMMOVE, dst, src, size, tailcall);
  99 }
 100
 101 inline rtx
 102 emit_block_comp_via_libcall (rtx dst, rtx src, rtx size, bool tailcall = false)
 103 {
 104   return emit_block_op_via_libcall (BUILT_IN_MEMCMP, dst, src, size, tailcall);
 105 }
 106
 107 /* Emit code to move a block Y to a block X.  */
 108 enum block_op_methods
 109 {
 110   BLOCK_OP_NORMAL,
 111   BLOCK_OP_NO_LIBCALL,
 112   BLOCK_OP_CALL_PARM,
 113   /* Like BLOCK_OP_NORMAL, but the libcall can be tail call optimized.  */
 114   BLOCK_OP_TAILCALL,
 115   /* Like BLOCK_OP_NO_LIBCALL, but instead of emitting a libcall return
 116      pc_rtx to indicate nothing has been emitted and let the caller handle
 117      it.  */
 118   BLOCK_OP_NO_LIBCALL_RET
 119 };
 120
 121 typedef rtx (*by_pieces_constfn) (void *, void *, HOST_WIDE_INT,
 122                                   fixed_size_mode);
 123
 124 /* The second pointer passed to by_pieces_constfn.  */
 125 struct by_pieces_prev
 126 {
 127   rtx data;
 128   fixed_size_mode mode;
 129 };
 130
 131 extern rtx emit_block_move (rtx, rtx, rtx, enum block_op_methods,
 132                             unsigned ctz_size = 0);
 133 extern rtx emit_block_move_hints (rtx, rtx, rtx, enum block_op_methods,
 134                                   unsigned int, HOST_WIDE_INT,
 135                                   unsigned HOST_WIDE_INT,
 136                                   unsigned HOST_WIDE_INT,
 137                                   unsigned HOST_WIDE_INT,
 138                                   bool bail_out_libcall = false,
 139                                   bool *is_move_done = NULL,
 140                                   bool might_overlap = false,
 141                                   unsigned ctz_size = 0);
 142 extern rtx emit_block_cmp_hints (rtx, rtx, rtx, tree, rtx, bool,
 143                                  by_pieces_constfn, void *,
 144                                  unsigned ctz_len = 0);
 145 extern bool emit_storent_insn (rtx to, rtx from);
 146
 147 /* Copy all or part of a value X into registers starting at REGNO.
 148    The number of registers to be filled is NREGS.  */
 149 extern void move_block_to_reg (int, rtx, int, machine_mode);
 150
 151 /* Copy all or part of a BLKmode value X out of registers starting at REGNO.
 152    The number of registers to be filled is NREGS.  */
 153 extern void move_block_from_reg (int, rtx, int);
 154
 155 /* Generate a non-consecutive group of registers represented by a PARALLEL.  */
 156 extern rtx gen_group_rtx (rtx);
 157
 158 /* Load a BLKmode value into non-consecutive registers represented by a
 159    PARALLEL.  */
 160 extern void emit_group_load (rtx, rtx, tree, poly_int64);
 161
 162 /* Similarly, but load into new temporaries.  */
 163 extern rtx emit_group_load_into_temps (rtx, rtx, tree, poly_int64);
 164
 165 /* Move a non-consecutive group of registers represented by a PARALLEL into
 166    a non-consecutive group of registers represented by a PARALLEL.  */
 167 extern void emit_group_move (rtx, rtx);
 168
 169 /* Move a group of registers represented by a PARALLEL into pseudos.  */
 170 extern rtx emit_group_move_into_temps (rtx);
 171
 172 /* Store a BLKmode value from non-consecutive registers represented by a
 173    PARALLEL.  */
 174 extern void emit_group_store (rtx, rtx, tree, poly_int64);
 175
 176 extern rtx maybe_emit_group_store (rtx, tree);
 177
 178 /* Mark REG as holding a parameter for the next CALL_INSN.
 179    Mode is TYPE_MODE of the non-promoted parameter, or VOIDmode.  */
 180 extern void use_reg_mode (rtx *, rtx, machine_mode);
 181 extern void clobber_reg_mode (rtx *, rtx, machine_mode);
 182
 183 extern rtx copy_blkmode_to_reg (machine_mode, tree);
 184
 185 /* Mark REG as holding a parameter for the next CALL_INSN.  */
 186 inline void
 187 use_reg (rtx *fusage, rtx reg)
 188 {
 189   use_reg_mode (fusage, reg, VOIDmode);
 190 }
 191
 192 /* Mark REG as clobbered by the call with FUSAGE as CALL_INSN_FUNCTION_USAGE.  */
 193 inline void
 194 clobber_reg (rtx *fusage, rtx reg)
 195 {
 196   clobber_reg_mode (fusage, reg, VOIDmode);
 197 }
 198
 199 /* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
 200    for the next CALL_INSN.  */
 201 extern void use_regs (rtx *, int, int);
 202
 203 /* Mark a PARALLEL as holding a parameter for the next CALL_INSN.  */
 204 extern void use_group_regs (rtx *, rtx);
 205
 206 #ifdef GCC_INSN_CODES_H
 207 extern rtx expand_cmpstrn_or_cmpmem (insn_code, rtx, rtx, rtx, tree, rtx,
 208                                      HOST_WIDE_INT);
 209 #endif
 210
 211 /* Write zeros through the storage of OBJECT.
 212    If OBJECT has BLKmode, SIZE is its length in bytes.  */
 213 extern rtx clear_storage (rtx, rtx, enum block_op_methods);
 214 extern rtx clear_storage_hints (rtx, rtx, enum block_op_methods,
 215                                 unsigned int, HOST_WIDE_INT,
 216                                 unsigned HOST_WIDE_INT,
 217                                 unsigned HOST_WIDE_INT,
 218                                 unsigned HOST_WIDE_INT,
 219                                 unsigned);
 220 /* The same, but always output an library call.  */
 221 extern rtx set_storage_via_libcall (rtx, rtx, rtx, bool = false);
 222
 223 /* Expand a setmem pattern; return true if successful.  */
 224 extern bool set_storage_via_setmem (rtx, rtx, rtx, unsigned int,
 225                                     unsigned int, HOST_WIDE_INT,
 226                                     unsigned HOST_WIDE_INT,
 227                                     unsigned HOST_WIDE_INT,
 228                                     unsigned HOST_WIDE_INT);
 229
 230 /* Return true if it is desirable to store LEN bytes generated by
 231    CONSTFUN with several move instructions by store_by_pieces
 232    function.  CONSTFUNDATA is a pointer which will be passed as argument
 233    in every CONSTFUN call.
 234    ALIGN is maximum alignment we can assume.
 235    MEMSETP is true if this is a real memset/bzero, not a copy
 236    of a const string.  */
 237 extern bool can_store_by_pieces (unsigned HOST_WIDE_INT,
 238                                  by_pieces_constfn,
 239                                  void *, unsigned int, bool);
 240
 241 /* Generate several move instructions to store LEN bytes generated by
 242    CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
 243    pointer which will be passed as argument in every CONSTFUN call.
 244    ALIGN is maximum alignment we can assume.
 245    MEMSETP is true if this is a real memset/bzero, not a copy.
 246    Returns TO + LEN.  */
 247 extern rtx store_by_pieces (rtx, unsigned HOST_WIDE_INT, by_pieces_constfn,
 248                             void *, unsigned int, bool, memop_ret);
 249
 250 /* Generate several move instructions to clear LEN bytes of block TO.  (A MEM
 251    rtx with BLKmode).  ALIGN is maximum alignment we can assume.  */
 252
 253 extern void clear_by_pieces (rtx, unsigned HOST_WIDE_INT, unsigned int);
 254
 255 /* If can_store_by_pieces passes for worst-case values near MAX_LEN, call
 256    store_by_pieces within conditionals so as to handle variable LEN efficiently,
 257    storing VAL, if non-NULL_RTX, or valc instead.  */
 258 extern bool try_store_by_multiple_pieces (rtx to, rtx len,
 259                                           unsigned int ctz_len,
 260                                           unsigned HOST_WIDE_INT min_len,
 261                                           unsigned HOST_WIDE_INT max_len,
 262                                           rtx val, char valc,
 263                                           unsigned int align);
 264
 265 /* Emit insns to set X from Y.  */
 266 extern rtx_insn *emit_move_insn (rtx, rtx);
 267 extern rtx_insn *gen_move_insn (rtx, rtx);
 268
 269 /* Emit insns to set X from Y, with no frills.  */
 270 extern rtx_insn *emit_move_insn_1 (rtx, rtx);
 271
 272 extern rtx_insn *emit_move_complex_push (machine_mode, rtx, rtx);
 273 extern rtx_insn *emit_move_complex_parts (rtx, rtx);
 274 extern rtx read_complex_part (rtx, bool);
 275 extern void write_complex_part (rtx, rtx, bool, bool);
 276 extern rtx read_complex_part (rtx, bool);
 277 extern rtx emit_move_resolve_push (machine_mode, rtx);
 278
 279 /* Push a block of length SIZE (perhaps variable)
 280    and return an rtx to address the beginning of the block.  */
 281 extern rtx push_block (rtx, poly_int64, int);
 282
 283 /* Generate code to push something onto the stack, given its mode and type.  */
 284 extern bool emit_push_insn (rtx, machine_mode, tree, rtx, unsigned int,
 285                             int, rtx, poly_int64, rtx, rtx, int, rtx, bool);
 286
 287 /* Extract the accessible bit-range from a COMPONENT_REF.  */
 288 extern void get_bit_range (poly_uint64 *, poly_uint64 *, tree,
 289                            poly_int64 *, tree *);
 290
 291 /* Expand an assignment that stores the value of FROM into TO.  */
 292 extern void expand_assignment (tree, tree, bool);
 293
 294 /* Generate code for computing expression EXP,
 295    and storing the value into TARGET.
 296    If SUGGEST_REG is nonzero, copy the value through a register
 297    and return that register, if that is possible.  */
 298 extern rtx store_expr (tree, rtx, int, bool, bool);
 299
 300 /* Given an rtx that may include add and multiply operations,
 301    generate them as insns and return a pseudo-reg containing the value.
 302    Useful after calling expand_expr with 1 as sum_ok.  */
 303 extern rtx force_operand (rtx, rtx);
 304
 305 /* Work horses for expand_expr.  */
 306 extern rtx expand_expr_real (tree, rtx, machine_mode,
 307                              enum expand_modifier, rtx *, bool);
 308 extern rtx expand_expr_real_1 (tree, rtx, machine_mode,
 309                                enum expand_modifier, rtx *, bool);
 310 extern rtx expand_expr_real_2 (const_sepops, rtx, machine_mode,
 311                                enum expand_modifier);
 312 extern rtx expand_expr_real_gassign (gassign *, rtx, machine_mode,
 313                                      enum expand_modifier modifier,
 314                                      rtx * = nullptr, bool = false);
 315
 316 /* Generate code for computing expression EXP.
 317    An rtx for the computed value is returned.  The value is never null.
 318    In the case of a void EXP, const0_rtx is returned.  */
 319 inline rtx
 320 expand_expr (tree exp, rtx target, machine_mode mode,
 321              enum expand_modifier modifier)
 322 {
 323   return expand_expr_real (exp, target, mode, modifier, NULL, false);
 324 }
 325
 326 inline rtx
 327 expand_normal (tree exp)
 328 {
 329   return expand_expr_real (exp, NULL_RTX, VOIDmode, EXPAND_NORMAL, NULL, false);
 330 }
 331
 332
 333 /* Return STRING_CST and set offset, size and decl, if the first
 334    argument corresponds to a string constant.  */
 335 extern tree string_constant (tree, tree *, tree *, tree *);
 336 /* Similar to string_constant, return a STRING_CST corresponding
 337    to the value representation of the first argument if it's
 338    a constant.  */
 339 extern tree byte_representation (tree, tree *, tree *, tree *);
 340
 341 extern enum tree_code maybe_optimize_mod_cmp (enum tree_code, tree *, tree *);
 342 extern void maybe_optimize_sub_cmp_0 (enum tree_code, tree *, tree *);
 343
 344 /* Two different ways of generating switch statements.  */
 345 extern bool try_casesi (tree, tree, tree, tree, rtx, rtx, rtx,
 346                         profile_probability);
 347 extern bool try_tablejump (tree, tree, tree, tree, rtx, rtx,
 348                            profile_probability);
 349
 350 extern bool safe_from_p (const_rtx, tree, int);
 351
 352 /* Get the personality libfunc for a function decl.  */
 353 rtx get_personality_function (tree);
 354
 355 /* Determine whether the LEN bytes can be moved by using several move
 356    instructions.  Return nonzero if a call to move_by_pieces should
 357    succeed.  */
 358 extern bool can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
 359
 360 extern unsigned HOST_WIDE_INT highest_pow2_factor (const_tree);
 361
 362 extern bool categorize_ctor_elements (const_tree, HOST_WIDE_INT *,
 363                                       HOST_WIDE_INT *, HOST_WIDE_INT *,
 364                                       int *);
 365 extern bool type_has_padding_at_level_p (tree);
 366 extern bool immediate_const_ctor_p (const_tree, unsigned int words = 1);
 367 extern void store_constructor (tree, rtx, int, poly_int64, bool);
 368 extern HOST_WIDE_INT int_expr_size (const_tree exp);
 369
 370 extern void expand_operands (tree, tree, rtx, rtx*, rtx*,
 371                              enum expand_modifier);
 372
 373 /* rtl.h and tree.h were included.  */
 374 /* Return an rtx for the size in bytes of the value of an expr.  */
 375 extern rtx expr_size (tree);
 376
 377 extern bool mem_ref_refers_to_non_mem_p (tree);
 378 extern bool non_mem_decl_p (tree);
 379
 380 #endif /* GCC_EXPR_H */