gcc/expr.h

   1 /* Definitions for code generation pass of GNU compiler.
   2    Copyright (C) 1987-2018 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 *, HOST_WIDE_INT, scalar_int_mode);
 111
 112 extern rtx emit_block_move (rtx, rtx, rtx, enum block_op_methods);
 113 extern rtx emit_block_move_hints (rtx, rtx, rtx, enum block_op_methods,
 114                                   unsigned int, HOST_WIDE_INT,
 115                                   unsigned HOST_WIDE_INT,
 116                                   unsigned HOST_WIDE_INT,
 117                                   unsigned HOST_WIDE_INT);
 118 extern rtx emit_block_cmp_hints (rtx, rtx, rtx, tree, rtx, bool,
 119                                  by_pieces_constfn, void *);
 120 extern bool emit_storent_insn (rtx to, rtx from);
 121
 122 /* Copy all or part of a value X into registers starting at REGNO.
 123    The number of registers to be filled is NREGS.  */
 124 extern void move_block_to_reg (int, rtx, int, machine_mode);
 125
 126 /* Copy all or part of a BLKmode value X out of registers starting at REGNO.
 127    The number of registers to be filled is NREGS.  */
 128 extern void move_block_from_reg (int, rtx, int);
 129
 130 /* Generate a non-consecutive group of registers represented by a PARALLEL.  */
 131 extern rtx gen_group_rtx (rtx);
 132
 133 /* Load a BLKmode value into non-consecutive registers represented by a
 134    PARALLEL.  */
 135 extern void emit_group_load (rtx, rtx, tree, poly_int64);
 136
 137 /* Similarly, but load into new temporaries.  */
 138 extern rtx emit_group_load_into_temps (rtx, rtx, tree, poly_int64);
 139
 140 /* Move a non-consecutive group of registers represented by a PARALLEL into
 141    a non-consecutive group of registers represented by a PARALLEL.  */
 142 extern void emit_group_move (rtx, rtx);
 143
 144 /* Move a group of registers represented by a PARALLEL into pseudos.  */
 145 extern rtx emit_group_move_into_temps (rtx);
 146
 147 /* Store a BLKmode value from non-consecutive registers represented by a
 148    PARALLEL.  */
 149 extern void emit_group_store (rtx, rtx, tree, poly_int64);
 150
 151 extern rtx maybe_emit_group_store (rtx, tree);
 152
 153 /* Mark REG as holding a parameter for the next CALL_INSN.
 154    Mode is TYPE_MODE of the non-promoted parameter, or VOIDmode.  */
 155 extern void use_reg_mode (rtx *, rtx, machine_mode);
 156 extern void clobber_reg_mode (rtx *, rtx, machine_mode);
 157
 158 extern rtx copy_blkmode_to_reg (machine_mode, tree);
 159
 160 /* Mark REG as holding a parameter for the next CALL_INSN.  */
 161 static inline void
 162 use_reg (rtx *fusage, rtx reg)
 163 {
 164   use_reg_mode (fusage, reg, VOIDmode);
 165 }
 166
 167 /* Mark REG as clobbered by the call with FUSAGE as CALL_INSN_FUNCTION_USAGE.  */
 168 static inline void
 169 clobber_reg (rtx *fusage, rtx reg)
 170 {
 171   clobber_reg_mode (fusage, reg, VOIDmode);
 172 }
 173
 174 /* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
 175    for the next CALL_INSN.  */
 176 extern void use_regs (rtx *, int, int);
 177
 178 /* Mark a PARALLEL as holding a parameter for the next CALL_INSN.  */
 179 extern void use_group_regs (rtx *, rtx);
 180
 181 #ifdef GCC_INSN_CODES_H
 182 extern rtx expand_cmpstrn_or_cmpmem (insn_code, rtx, rtx, rtx, tree, rtx,
 183                                      HOST_WIDE_INT);
 184 #endif
 185
 186 /* Write zeros through the storage of OBJECT.
 187    If OBJECT has BLKmode, SIZE is its length in bytes.  */
 188 extern rtx clear_storage (rtx, rtx, enum block_op_methods);
 189 extern rtx clear_storage_hints (rtx, rtx, enum block_op_methods,
 190                                 unsigned int, HOST_WIDE_INT,
 191                                 unsigned HOST_WIDE_INT,
 192                                 unsigned HOST_WIDE_INT,
 193                                 unsigned HOST_WIDE_INT);
 194 /* The same, but always output an library call.  */
 195 extern rtx set_storage_via_libcall (rtx, rtx, rtx, bool = false);
 196
 197 /* Expand a setmem pattern; return true if successful.  */
 198 extern bool set_storage_via_setmem (rtx, rtx, rtx, unsigned int,
 199                                     unsigned int, HOST_WIDE_INT,
 200                                     unsigned HOST_WIDE_INT,
 201                                     unsigned HOST_WIDE_INT,
 202                                     unsigned HOST_WIDE_INT);
 203
 204 /* Return nonzero if it is desirable to store LEN bytes generated by
 205    CONSTFUN with several move instructions by store_by_pieces
 206    function.  CONSTFUNDATA is a pointer which will be passed as argument
 207    in every CONSTFUN call.
 208    ALIGN is maximum alignment we can assume.
 209    MEMSETP is true if this is a real memset/bzero, not a copy
 210    of a const string.  */
 211 extern int can_store_by_pieces (unsigned HOST_WIDE_INT,
 212                                 by_pieces_constfn,
 213                                 void *, unsigned int, bool);
 214
 215 /* Generate several move instructions to store LEN bytes generated by
 216    CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
 217    pointer which will be passed as argument in every CONSTFUN call.
 218    ALIGN is maximum alignment we can assume.
 219    MEMSETP is true if this is a real memset/bzero, not a copy.
 220    Returns TO + LEN.  */
 221 extern rtx store_by_pieces (rtx, unsigned HOST_WIDE_INT, by_pieces_constfn,
 222                             void *, unsigned int, bool, int);
 223
 224 /* Emit insns to set X from Y.  */
 225 extern rtx_insn *emit_move_insn (rtx, rtx);
 226 extern rtx_insn *gen_move_insn (rtx, rtx);
 227
 228 /* Emit insns to set X from Y, with no frills.  */
 229 extern rtx_insn *emit_move_insn_1 (rtx, rtx);
 230
 231 extern rtx_insn *emit_move_complex_push (machine_mode, rtx, rtx);
 232 extern rtx_insn *emit_move_complex_parts (rtx, rtx);
 233 extern rtx read_complex_part (rtx, bool);
 234 extern void write_complex_part (rtx, rtx, bool);
 235 extern rtx read_complex_part (rtx, bool);
 236 extern rtx emit_move_resolve_push (machine_mode, rtx);
 237
 238 /* Push a block of length SIZE (perhaps variable)
 239    and return an rtx to address the beginning of the block.  */
 240 extern rtx push_block (rtx, poly_int64, int);
 241
 242 /* Generate code to push something onto the stack, given its mode and type.  */
 243 extern bool emit_push_insn (rtx, machine_mode, tree, rtx, unsigned int,
 244                             int, rtx, poly_int64, rtx, rtx, int, rtx, bool);
 245
 246 /* Extract the accessible bit-range from a COMPONENT_REF.  */
 247 extern void get_bit_range (poly_uint64_pod *, poly_uint64_pod *, tree,
 248                            poly_int64_pod *, tree *);
 249
 250 /* Expand an assignment that stores the value of FROM into TO.  */
 251 extern void expand_assignment (tree, tree, bool);
 252
 253 /* Generate code for computing expression EXP,
 254    and storing the value into TARGET.
 255    If SUGGEST_REG is nonzero, copy the value through a register
 256    and return that register, if that is possible.  */
 257 extern rtx store_expr (tree, rtx, int, bool, bool);
 258
 259 /* Given an rtx that may include add and multiply operations,
 260    generate them as insns and return a pseudo-reg containing the value.
 261    Useful after calling expand_expr with 1 as sum_ok.  */
 262 extern rtx force_operand (rtx, rtx);
 263
 264 /* Work horses for expand_expr.  */
 265 extern rtx expand_expr_real (tree, rtx, machine_mode,
 266                              enum expand_modifier, rtx *, bool);
 267 extern rtx expand_expr_real_1 (tree, rtx, machine_mode,
 268                                enum expand_modifier, rtx *, bool);
 269 extern rtx expand_expr_real_2 (sepops, rtx, machine_mode,
 270                                enum expand_modifier);
 271
 272 /* Generate code for computing expression EXP.
 273    An rtx for the computed value is returned.  The value is never null.
 274    In the case of a void EXP, const0_rtx is returned.  */
 275 static inline rtx
 276 expand_expr (tree exp, rtx target, machine_mode mode,
 277              enum expand_modifier modifier)
 278 {
 279   return expand_expr_real (exp, target, mode, modifier, NULL, false);
 280 }
 281
 282 static inline rtx
 283 expand_normal (tree exp)
 284 {
 285   return expand_expr_real (exp, NULL_RTX, VOIDmode, EXPAND_NORMAL, NULL, false);
 286 }
 287
 288
 289 /* Return the tree node and offset if a given argument corresponds to
 290    a string constant.  */
 291 extern tree string_constant (tree, tree *, tree *, tree *);
 292
 293 extern enum tree_code maybe_optimize_mod_cmp (enum tree_code, tree *, tree *);
 294
 295 /* Two different ways of generating switch statements.  */
 296 extern int try_casesi (tree, tree, tree, tree, rtx, rtx, rtx, profile_probability);
 297 extern int try_tablejump (tree, tree, tree, tree, rtx, rtx, profile_probability);
 298
 299 extern int safe_from_p (const_rtx, tree, int);
 300
 301 /* Get the personality libfunc for a function decl.  */
 302 rtx get_personality_function (tree);
 303
 304 /* Determine whether the LEN bytes can be moved by using several move
 305    instructions.  Return nonzero if a call to move_by_pieces should
 306    succeed.  */
 307 extern bool can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
 308
 309 extern unsigned HOST_WIDE_INT highest_pow2_factor (const_tree);
 310
 311 extern bool categorize_ctor_elements (const_tree, HOST_WIDE_INT *,
 312                                       HOST_WIDE_INT *, bool *);
 313
 314 extern void expand_operands (tree, tree, rtx, rtx*, rtx*,
 315                              enum expand_modifier);
 316
 317 /* rtl.h and tree.h were included.  */
 318 /* Return an rtx for the size in bytes of the value of an expr.  */
 319 extern rtx expr_size (tree);
 320
 321 #endif /* GCC_EXPR_H */