gcc/expr.h

   1 /* Definitions for code generation pass of GNU compiler.
   2    Copyright (C) 1987-2023 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 \f
  57 /* This is run during target initialization to set up which modes can be
  58    used directly in memory and to initialize the block move optab.  */
  59 extern void init_expr_target (void);
  60
  61 /* This is run at the start of compiling a function.  */
  62 extern void init_expr (void);
  63
  64 /* Emit some rtl insns to move data between rtx's, converting machine modes.
  65    Both modes must be floating or both fixed.  */
  66 extern void convert_move (rtx, rtx, int);
  67
  68 /* Convert an rtx to specified machine mode and return the result.  */
  69 extern rtx convert_to_mode (machine_mode, rtx, int);
  70
  71 /* Convert an rtx to MODE from OLDMODE and return the result.  */
  72 extern rtx convert_modes (machine_mode mode, machine_mode oldmode,
  73                           rtx x, int unsignedp);
  74
  75 /* Variant of convert_modes for ABI parameter passing/return.  */
  76 extern rtx convert_float_to_wider_int (machine_mode mode, machine_mode fmode,
  77                                        rtx x);
  78
  79 /* Variant of convert_modes for ABI parameter passing/return.  */
  80 extern rtx convert_wider_int_to_float (machine_mode mode, machine_mode imode,
  81                                        rtx x);
  82
  83 /* Expand a call to memcpy or memmove or memcmp, and return the result.  */
  84 extern rtx emit_block_op_via_libcall (enum built_in_function, rtx, rtx, rtx,
  85                                       bool);
  86
  87 static inline rtx
  88 emit_block_copy_via_libcall (rtx dst, rtx src, rtx size, bool tailcall = false)
  89 {
  90   return emit_block_op_via_libcall (BUILT_IN_MEMCPY, dst, src, size, tailcall);
  91 }
  92
  93 static inline rtx
  94 emit_block_move_via_libcall (rtx dst, rtx src, rtx size, bool tailcall = false)
  95 {
  96   return emit_block_op_via_libcall (BUILT_IN_MEMMOVE, dst, src, size, tailcall);
  97 }
  98
  99 static inline rtx
 100 emit_block_comp_via_libcall (rtx dst, rtx src, rtx size, bool tailcall = false)
 101 {
 102   return emit_block_op_via_libcall (BUILT_IN_MEMCMP, dst, src, size, tailcall);
 103 }
 104
 105 /* Emit code to move a block Y to a block X.  */
 106 enum block_op_methods
 107 {
 108   BLOCK_OP_NORMAL,
 109   BLOCK_OP_NO_LIBCALL,
 110   BLOCK_OP_CALL_PARM,
 111   /* Like BLOCK_OP_NORMAL, but the libcall can be tail call optimized.  */
 112   BLOCK_OP_TAILCALL,
 113   /* Like BLOCK_OP_NO_LIBCALL, but instead of emitting a libcall return
 114      pc_rtx to indicate nothing has been emitted and let the caller handle
 115      it.  */
 116   BLOCK_OP_NO_LIBCALL_RET
 117 };
 118
 119 typedef rtx (*by_pieces_constfn) (void *, void *, HOST_WIDE_INT,
 120                                   fixed_size_mode);
 121
 122 /* The second pointer passed to by_pieces_constfn.  */
 123 struct by_pieces_prev
 124 {
 125   rtx data;
 126   fixed_size_mode mode;
 127 };
 128
 129 extern rtx emit_block_move (rtx, rtx, rtx, enum block_op_methods);
 130 extern rtx emit_block_move_hints (rtx, rtx, rtx, enum block_op_methods,
 131                                   unsigned int, HOST_WIDE_INT,
 132                                   unsigned HOST_WIDE_INT,
 133                                   unsigned HOST_WIDE_INT,
 134                                   unsigned HOST_WIDE_INT,
 135                                   bool bail_out_libcall = false,
 136                                   bool *is_move_done = NULL,
 137                                   bool might_overlap = false);
 138 extern rtx emit_block_cmp_hints (rtx, rtx, rtx, tree, rtx, bool,
 139                                  by_pieces_constfn, void *);
 140 extern bool emit_storent_insn (rtx to, rtx from);
 141
 142 /* Copy all or part of a value X into registers starting at REGNO.
 143    The number of registers to be filled is NREGS.  */
 144 extern void move_block_to_reg (int, rtx, int, machine_mode);
 145
 146 /* Copy all or part of a BLKmode value X out of registers starting at REGNO.
 147    The number of registers to be filled is NREGS.  */
 148 extern void move_block_from_reg (int, rtx, int);
 149
 150 /* Generate a non-consecutive group of registers represented by a PARALLEL.  */
 151 extern rtx gen_group_rtx (rtx);
 152
 153 /* Load a BLKmode value into non-consecutive registers represented by a
 154    PARALLEL.  */
 155 extern void emit_group_load (rtx, rtx, tree, poly_int64);
 156
 157 /* Similarly, but load into new temporaries.  */
 158 extern rtx emit_group_load_into_temps (rtx, rtx, tree, poly_int64);
 159
 160 /* Move a non-consecutive group of registers represented by a PARALLEL into
 161    a non-consecutive group of registers represented by a PARALLEL.  */
 162 extern void emit_group_move (rtx, rtx);
 163
 164 /* Move a group of registers represented by a PARALLEL into pseudos.  */
 165 extern rtx emit_group_move_into_temps (rtx);
 166
 167 /* Store a BLKmode value from non-consecutive registers represented by a
 168    PARALLEL.  */
 169 extern void emit_group_store (rtx, rtx, tree, poly_int64);
 170
 171 extern rtx maybe_emit_group_store (rtx, tree);
 172
 173 /* Mark REG as holding a parameter for the next CALL_INSN.
 174    Mode is TYPE_MODE of the non-promoted parameter, or VOIDmode.  */
 175 extern void use_reg_mode (rtx *, rtx, machine_mode);
 176 extern void clobber_reg_mode (rtx *, rtx, machine_mode);
 177
 178 extern rtx copy_blkmode_to_reg (machine_mode, tree);
 179
 180 /* Mark REG as holding a parameter for the next CALL_INSN.  */
 181 static inline void
 182 use_reg (rtx *fusage, rtx reg)
 183 {
 184   use_reg_mode (fusage, reg, VOIDmode);
 185 }
 186
 187 /* Mark REG as clobbered by the call with FUSAGE as CALL_INSN_FUNCTION_USAGE.  */
 188 static inline void
 189 clobber_reg (rtx *fusage, rtx reg)
 190 {
 191   clobber_reg_mode (fusage, reg, VOIDmode);
 192 }
 193
 194 /* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
 195    for the next CALL_INSN.  */
 196 extern void use_regs (rtx *, int, int);
 197
 198 /* Mark a PARALLEL as holding a parameter for the next CALL_INSN.  */
 199 extern void use_group_regs (rtx *, rtx);
 200
 201 #ifdef GCC_INSN_CODES_H
 202 extern rtx expand_cmpstrn_or_cmpmem (insn_code, rtx, rtx, rtx, tree, rtx,
 203                                      HOST_WIDE_INT);
 204 #endif
 205
 206 /* Write zeros through the storage of OBJECT.
 207    If OBJECT has BLKmode, SIZE is its length in bytes.  */
 208 extern rtx clear_storage (rtx, rtx, enum block_op_methods);
 209 extern rtx clear_storage_hints (rtx, rtx, enum block_op_methods,
 210                                 unsigned int, HOST_WIDE_INT,
 211                                 unsigned HOST_WIDE_INT,
 212                                 unsigned HOST_WIDE_INT,
 213                                 unsigned HOST_WIDE_INT,
 214                                 unsigned);
 215 /* The same, but always output an library call.  */
 216 extern rtx set_storage_via_libcall (rtx, rtx, rtx, bool = false);
 217
 218 /* Expand a setmem pattern; return true if successful.  */
 219 extern bool set_storage_via_setmem (rtx, rtx, rtx, unsigned int,
 220                                     unsigned int, HOST_WIDE_INT,
 221                                     unsigned HOST_WIDE_INT,
 222                                     unsigned HOST_WIDE_INT,
 223                                     unsigned HOST_WIDE_INT);
 224
 225 /* Return nonzero if it is desirable to store LEN bytes generated by
 226    CONSTFUN with several move instructions by store_by_pieces
 227    function.  CONSTFUNDATA is a pointer which will be passed as argument
 228    in every CONSTFUN call.
 229    ALIGN is maximum alignment we can assume.
 230    MEMSETP is true if this is a real memset/bzero, not a copy
 231    of a const string.  */
 232 extern int can_store_by_pieces (unsigned HOST_WIDE_INT,
 233                                 by_pieces_constfn,
 234                                 void *, unsigned int, bool);
 235
 236 /* Generate several move instructions to store LEN bytes generated by
 237    CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
 238    pointer which will be passed as argument in every CONSTFUN call.
 239    ALIGN is maximum alignment we can assume.
 240    MEMSETP is true if this is a real memset/bzero, not a copy.
 241    Returns TO + LEN.  */
 242 extern rtx store_by_pieces (rtx, unsigned HOST_WIDE_INT, by_pieces_constfn,
 243                             void *, unsigned int, bool, memop_ret);
 244
 245 /* If can_store_by_pieces passes for worst-case values near MAX_LEN, call
 246    store_by_pieces within conditionals so as to handle variable LEN efficiently,
 247    storing VAL, if non-NULL_RTX, or valc instead.  */
 248 extern bool try_store_by_multiple_pieces (rtx to, rtx len,
 249                                           unsigned int ctz_len,
 250                                           unsigned HOST_WIDE_INT min_len,
 251                                           unsigned HOST_WIDE_INT max_len,
 252                                           rtx val, char valc,
 253                                           unsigned int align);
 254
 255 /* Emit insns to set X from Y.  */
 256 extern rtx_insn *emit_move_insn (rtx, rtx);
 257 extern rtx_insn *gen_move_insn (rtx, rtx);
 258
 259 /* Emit insns to set X from Y, with no frills.  */
 260 extern rtx_insn *emit_move_insn_1 (rtx, rtx);
 261
 262 extern rtx_insn *emit_move_complex_push (machine_mode, rtx, rtx);
 263 extern rtx_insn *emit_move_complex_parts (rtx, rtx);
 264 extern rtx read_complex_part (rtx, bool);
 265 extern void write_complex_part (rtx, rtx, bool, bool);
 266 extern rtx read_complex_part (rtx, bool);
 267 extern rtx emit_move_resolve_push (machine_mode, rtx);
 268
 269 /* Push a block of length SIZE (perhaps variable)
 270    and return an rtx to address the beginning of the block.  */
 271 extern rtx push_block (rtx, poly_int64, int);
 272
 273 /* Generate code to push something onto the stack, given its mode and type.  */
 274 extern bool emit_push_insn (rtx, machine_mode, tree, rtx, unsigned int,
 275                             int, rtx, poly_int64, rtx, rtx, int, rtx, bool);
 276
 277 /* Extract the accessible bit-range from a COMPONENT_REF.  */
 278 extern void get_bit_range (poly_uint64_pod *, poly_uint64_pod *, tree,
 279                            poly_int64_pod *, tree *);
 280
 281 /* Expand an assignment that stores the value of FROM into TO.  */
 282 extern void expand_assignment (tree, tree, bool);
 283
 284 /* Generate code for computing expression EXP,
 285    and storing the value into TARGET.
 286    If SUGGEST_REG is nonzero, copy the value through a register
 287    and return that register, if that is possible.  */
 288 extern rtx store_expr (tree, rtx, int, bool, bool);
 289
 290 /* Given an rtx that may include add and multiply operations,
 291    generate them as insns and return a pseudo-reg containing the value.
 292    Useful after calling expand_expr with 1 as sum_ok.  */
 293 extern rtx force_operand (rtx, rtx);
 294
 295 /* Work horses for expand_expr.  */
 296 extern rtx expand_expr_real (tree, rtx, machine_mode,
 297                              enum expand_modifier, rtx *, bool);
 298 extern rtx expand_expr_real_1 (tree, rtx, machine_mode,
 299                                enum expand_modifier, rtx *, bool);
 300 extern rtx expand_expr_real_2 (sepops, rtx, machine_mode,
 301                                enum expand_modifier);
 302
 303 /* Generate code for computing expression EXP.
 304    An rtx for the computed value is returned.  The value is never null.
 305    In the case of a void EXP, const0_rtx is returned.  */
 306 static inline rtx
 307 expand_expr (tree exp, rtx target, machine_mode mode,
 308              enum expand_modifier modifier)
 309 {
 310   return expand_expr_real (exp, target, mode, modifier, NULL, false);
 311 }
 312
 313 static inline rtx
 314 expand_normal (tree exp)
 315 {
 316   return expand_expr_real (exp, NULL_RTX, VOIDmode, EXPAND_NORMAL, NULL, false);
 317 }
 318
 319
 320 /* Return STRING_CST and set offset, size and decl, if the first
 321    argument corresponds to a string constant.  */
 322 extern tree string_constant (tree, tree *, tree *, tree *);
 323 /* Similar to string_constant, return a STRING_CST corresponding
 324    to the value representation of the first argument if it's
 325    a constant.  */
 326 extern tree byte_representation (tree, tree *, tree *, tree *);
 327
 328 extern enum tree_code maybe_optimize_mod_cmp (enum tree_code, tree *, tree *);
 329 extern void maybe_optimize_sub_cmp_0 (enum tree_code, tree *, tree *);
 330
 331 /* Two different ways of generating switch statements.  */
 332 extern int try_casesi (tree, tree, tree, tree, rtx, rtx, rtx, profile_probability);
 333 extern int try_tablejump (tree, tree, tree, tree, rtx, rtx, profile_probability);
 334
 335 extern int safe_from_p (const_rtx, tree, int);
 336
 337 /* Get the personality libfunc for a function decl.  */
 338 rtx get_personality_function (tree);
 339
 340 /* Determine whether the LEN bytes can be moved by using several move
 341    instructions.  Return nonzero if a call to move_by_pieces should
 342    succeed.  */
 343 extern bool can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
 344
 345 extern unsigned HOST_WIDE_INT highest_pow2_factor (const_tree);
 346
 347 extern bool categorize_ctor_elements (const_tree, HOST_WIDE_INT *,
 348                                       HOST_WIDE_INT *, HOST_WIDE_INT *,
 349                                       bool *);
 350 extern bool immediate_const_ctor_p (const_tree, unsigned int words = 1);
 351 extern void store_constructor (tree, rtx, int, poly_int64, bool);
 352 extern HOST_WIDE_INT int_expr_size (const_tree exp);
 353
 354 extern void expand_operands (tree, tree, rtx, rtx*, rtx*,
 355                              enum expand_modifier);
 356
 357 /* rtl.h and tree.h were included.  */
 358 /* Return an rtx for the size in bytes of the value of an expr.  */
 359 extern rtx expr_size (tree);
 360
 361 extern bool mem_ref_refers_to_non_mem_p (tree);
 362 extern bool non_mem_decl_p (tree);
 363
 364 #endif /* GCC_EXPR_H */