gcc/expr.h

   1 /* Definitions for code generation pass of GNU compiler.
   2    Copyright (C) 1987-2021 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, machine_mode, rtx, int);
  73
  74 /* Expand a call to memcpy or memmove or memcmp, and return the result.  */
  75 extern rtx emit_block_op_via_libcall (enum built_in_function, rtx, rtx, rtx,
  76                                       bool);
  77
  78 static inline rtx
  79 emit_block_copy_via_libcall (rtx dst, rtx src, rtx size, bool tailcall = false)
  80 {
  81   return emit_block_op_via_libcall (BUILT_IN_MEMCPY, dst, src, size, tailcall);
  82 }
  83
  84 static inline rtx
  85 emit_block_move_via_libcall (rtx dst, rtx src, rtx size, bool tailcall = false)
  86 {
  87   return emit_block_op_via_libcall (BUILT_IN_MEMMOVE, dst, src, size, tailcall);
  88 }
  89
  90 static inline rtx
  91 emit_block_comp_via_libcall (rtx dst, rtx src, rtx size, bool tailcall = false)
  92 {
  93   return emit_block_op_via_libcall (BUILT_IN_MEMCMP, dst, src, size, tailcall);
  94 }
  95
  96 /* Emit code to move a block Y to a block X.  */
  97 enum block_op_methods
  98 {
  99   BLOCK_OP_NORMAL,
 100   BLOCK_OP_NO_LIBCALL,
 101   BLOCK_OP_CALL_PARM,
 102   /* Like BLOCK_OP_NORMAL, but the libcall can be tail call optimized.  */
 103   BLOCK_OP_TAILCALL,
 104   /* Like BLOCK_OP_NO_LIBCALL, but instead of emitting a libcall return
 105      pc_rtx to indicate nothing has been emitted and let the caller handle
 106      it.  */
 107   BLOCK_OP_NO_LIBCALL_RET
 108 };
 109
 110 typedef rtx (*by_pieces_constfn) (void *, void *, HOST_WIDE_INT,
 111                                   fixed_size_mode);
 112
 113 /* The second pointer passed to by_pieces_constfn.  */
 114 struct by_pieces_prev
 115 {
 116   rtx data;
 117   fixed_size_mode mode;
 118 };
 119
 120 extern rtx emit_block_move (rtx, rtx, rtx, enum block_op_methods);
 121 extern rtx emit_block_move_hints (rtx, rtx, rtx, enum block_op_methods,
 122                                   unsigned int, HOST_WIDE_INT,
 123                                   unsigned HOST_WIDE_INT,
 124                                   unsigned HOST_WIDE_INT,
 125                                   unsigned HOST_WIDE_INT,
 126                                   bool bail_out_libcall = false,
 127                                   bool *is_move_done = NULL,
 128                                   bool might_overlap = false);
 129 extern rtx emit_block_cmp_hints (rtx, rtx, rtx, tree, rtx, bool,
 130                                  by_pieces_constfn, void *);
 131 extern bool emit_storent_insn (rtx to, rtx from);
 132
 133 /* Copy all or part of a value X into registers starting at REGNO.
 134    The number of registers to be filled is NREGS.  */
 135 extern void move_block_to_reg (int, rtx, int, machine_mode);
 136
 137 /* Copy all or part of a BLKmode value X out of registers starting at REGNO.
 138    The number of registers to be filled is NREGS.  */
 139 extern void move_block_from_reg (int, rtx, int);
 140
 141 /* Generate a non-consecutive group of registers represented by a PARALLEL.  */
 142 extern rtx gen_group_rtx (rtx);
 143
 144 /* Load a BLKmode value into non-consecutive registers represented by a
 145    PARALLEL.  */
 146 extern void emit_group_load (rtx, rtx, tree, poly_int64);
 147
 148 /* Similarly, but load into new temporaries.  */
 149 extern rtx emit_group_load_into_temps (rtx, rtx, tree, poly_int64);
 150
 151 /* Move a non-consecutive group of registers represented by a PARALLEL into
 152    a non-consecutive group of registers represented by a PARALLEL.  */
 153 extern void emit_group_move (rtx, rtx);
 154
 155 /* Move a group of registers represented by a PARALLEL into pseudos.  */
 156 extern rtx emit_group_move_into_temps (rtx);
 157
 158 /* Store a BLKmode value from non-consecutive registers represented by a
 159    PARALLEL.  */
 160 extern void emit_group_store (rtx, rtx, tree, poly_int64);
 161
 162 extern rtx maybe_emit_group_store (rtx, tree);
 163
 164 /* Mark REG as holding a parameter for the next CALL_INSN.
 165    Mode is TYPE_MODE of the non-promoted parameter, or VOIDmode.  */
 166 extern void use_reg_mode (rtx *, rtx, machine_mode);
 167 extern void clobber_reg_mode (rtx *, rtx, machine_mode);
 168
 169 extern rtx copy_blkmode_to_reg (machine_mode, tree);
 170
 171 /* Mark REG as holding a parameter for the next CALL_INSN.  */
 172 static inline void
 173 use_reg (rtx *fusage, rtx reg)
 174 {
 175   use_reg_mode (fusage, reg, VOIDmode);
 176 }
 177
 178 /* Mark REG as clobbered by the call with FUSAGE as CALL_INSN_FUNCTION_USAGE.  */
 179 static inline void
 180 clobber_reg (rtx *fusage, rtx reg)
 181 {
 182   clobber_reg_mode (fusage, reg, VOIDmode);
 183 }
 184
 185 /* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
 186    for the next CALL_INSN.  */
 187 extern void use_regs (rtx *, int, int);
 188
 189 /* Mark a PARALLEL as holding a parameter for the next CALL_INSN.  */
 190 extern void use_group_regs (rtx *, rtx);
 191
 192 #ifdef GCC_INSN_CODES_H
 193 extern rtx expand_cmpstrn_or_cmpmem (insn_code, rtx, rtx, rtx, tree, rtx,
 194                                      HOST_WIDE_INT);
 195 #endif
 196
 197 /* Write zeros through the storage of OBJECT.
 198    If OBJECT has BLKmode, SIZE is its length in bytes.  */
 199 extern rtx clear_storage (rtx, rtx, enum block_op_methods);
 200 extern rtx clear_storage_hints (rtx, rtx, enum block_op_methods,
 201                                 unsigned int, HOST_WIDE_INT,
 202                                 unsigned HOST_WIDE_INT,
 203                                 unsigned HOST_WIDE_INT,
 204                                 unsigned HOST_WIDE_INT,
 205                                 unsigned);
 206 /* The same, but always output an library call.  */
 207 extern rtx set_storage_via_libcall (rtx, rtx, rtx, bool = false);
 208
 209 /* Expand a setmem pattern; return true if successful.  */
 210 extern bool set_storage_via_setmem (rtx, rtx, rtx, unsigned int,
 211                                     unsigned int, HOST_WIDE_INT,
 212                                     unsigned HOST_WIDE_INT,
 213                                     unsigned HOST_WIDE_INT,
 214                                     unsigned HOST_WIDE_INT);
 215
 216 /* Return nonzero if it is desirable to store LEN bytes generated by
 217    CONSTFUN with several move instructions by store_by_pieces
 218    function.  CONSTFUNDATA is a pointer which will be passed as argument
 219    in every CONSTFUN call.
 220    ALIGN is maximum alignment we can assume.
 221    MEMSETP is true if this is a real memset/bzero, not a copy
 222    of a const string.  */
 223 extern int can_store_by_pieces (unsigned HOST_WIDE_INT,
 224                                 by_pieces_constfn,
 225                                 void *, unsigned int, bool);
 226
 227 /* Generate several move instructions to store LEN bytes generated by
 228    CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
 229    pointer which will be passed as argument in every CONSTFUN call.
 230    ALIGN is maximum alignment we can assume.
 231    MEMSETP is true if this is a real memset/bzero, not a copy.
 232    Returns TO + LEN.  */
 233 extern rtx store_by_pieces (rtx, unsigned HOST_WIDE_INT, by_pieces_constfn,
 234                             void *, unsigned int, bool, memop_ret);
 235
 236 /* If can_store_by_pieces passes for worst-case values near MAX_LEN, call
 237    store_by_pieces within conditionals so as to handle variable LEN efficiently,
 238    storing VAL, if non-NULL_RTX, or valc instead.  */
 239 extern bool try_store_by_multiple_pieces (rtx to, rtx len,
 240                                           unsigned int ctz_len,
 241                                           unsigned HOST_WIDE_INT min_len,
 242                                           unsigned HOST_WIDE_INT max_len,
 243                                           rtx val, char valc,
 244                                           unsigned int align);
 245
 246 /* Emit insns to set X from Y.  */
 247 extern rtx_insn *emit_move_insn (rtx, rtx);
 248 extern rtx_insn *gen_move_insn (rtx, rtx);
 249
 250 /* Emit insns to set X from Y, with no frills.  */
 251 extern rtx_insn *emit_move_insn_1 (rtx, rtx);
 252
 253 extern rtx_insn *emit_move_complex_push (machine_mode, rtx, rtx);
 254 extern rtx_insn *emit_move_complex_parts (rtx, rtx);
 255 extern rtx read_complex_part (rtx, bool);
 256 extern void write_complex_part (rtx, rtx, bool);
 257 extern rtx read_complex_part (rtx, bool);
 258 extern rtx emit_move_resolve_push (machine_mode, rtx);
 259
 260 /* Push a block of length SIZE (perhaps variable)
 261    and return an rtx to address the beginning of the block.  */
 262 extern rtx push_block (rtx, poly_int64, int);
 263
 264 /* Generate code to push something onto the stack, given its mode and type.  */
 265 extern bool emit_push_insn (rtx, machine_mode, tree, rtx, unsigned int,
 266                             int, rtx, poly_int64, rtx, rtx, int, rtx, bool);
 267
 268 /* Extract the accessible bit-range from a COMPONENT_REF.  */
 269 extern void get_bit_range (poly_uint64_pod *, poly_uint64_pod *, tree,
 270                            poly_int64_pod *, tree *);
 271
 272 /* Expand an assignment that stores the value of FROM into TO.  */
 273 extern void expand_assignment (tree, tree, bool);
 274
 275 /* Generate code for computing expression EXP,
 276    and storing the value into TARGET.
 277    If SUGGEST_REG is nonzero, copy the value through a register
 278    and return that register, if that is possible.  */
 279 extern rtx store_expr (tree, rtx, int, bool, bool);
 280
 281 /* Given an rtx that may include add and multiply operations,
 282    generate them as insns and return a pseudo-reg containing the value.
 283    Useful after calling expand_expr with 1 as sum_ok.  */
 284 extern rtx force_operand (rtx, rtx);
 285
 286 /* Work horses for expand_expr.  */
 287 extern rtx expand_expr_real (tree, rtx, machine_mode,
 288                              enum expand_modifier, rtx *, bool);
 289 extern rtx expand_expr_real_1 (tree, rtx, machine_mode,
 290                                enum expand_modifier, rtx *, bool);
 291 extern rtx expand_expr_real_2 (sepops, rtx, machine_mode,
 292                                enum expand_modifier);
 293
 294 /* Generate code for computing expression EXP.
 295    An rtx for the computed value is returned.  The value is never null.
 296    In the case of a void EXP, const0_rtx is returned.  */
 297 static inline rtx
 298 expand_expr (tree exp, rtx target, machine_mode mode,
 299              enum expand_modifier modifier)
 300 {
 301   return expand_expr_real (exp, target, mode, modifier, NULL, false);
 302 }
 303
 304 static inline rtx
 305 expand_normal (tree exp)
 306 {
 307   return expand_expr_real (exp, NULL_RTX, VOIDmode, EXPAND_NORMAL, NULL, false);
 308 }
 309
 310
 311 /* Return STRING_CST and set offset, size and decl, if the first
 312    argument corresponds to a string constant.  */
 313 extern tree string_constant (tree, tree *, tree *, tree *);
 314 /* Similar to string_constant, return a STRING_CST corresponding
 315    to the value representation of the first argument if it's
 316    a constant.  */
 317 extern tree byte_representation (tree, tree *, tree *, tree *);
 318
 319 extern enum tree_code maybe_optimize_mod_cmp (enum tree_code, tree *, tree *);
 320 extern void maybe_optimize_sub_cmp_0 (enum tree_code, tree *, tree *);
 321
 322 /* Two different ways of generating switch statements.  */
 323 extern int try_casesi (tree, tree, tree, tree, rtx, rtx, rtx, profile_probability);
 324 extern int try_tablejump (tree, tree, tree, tree, rtx, rtx, profile_probability);
 325
 326 extern int safe_from_p (const_rtx, tree, int);
 327
 328 /* Get the personality libfunc for a function decl.  */
 329 rtx get_personality_function (tree);
 330
 331 /* Determine whether the LEN bytes can be moved by using several move
 332    instructions.  Return nonzero if a call to move_by_pieces should
 333    succeed.  */
 334 extern bool can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
 335
 336 extern unsigned HOST_WIDE_INT highest_pow2_factor (const_tree);
 337
 338 extern bool categorize_ctor_elements (const_tree, HOST_WIDE_INT *,
 339                                       HOST_WIDE_INT *, HOST_WIDE_INT *,
 340                                       bool *);
 341
 342 extern void expand_operands (tree, tree, rtx, rtx*, rtx*,
 343                              enum expand_modifier);
 344
 345 /* rtl.h and tree.h were included.  */
 346 /* Return an rtx for the size in bytes of the value of an expr.  */
 347 extern rtx expr_size (tree);
 348
 349 extern bool mem_ref_refers_to_non_mem_p (tree);
 350 extern bool non_mem_decl_p (tree);
 351
 352 #endif /* GCC_EXPR_H */