gcc/expr.h

   1 /* Definitions for code generation pass of GNU compiler.
   2    Copyright (C) 1987, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  21
  22 /* The default branch cost is 1.  */
  23 #ifndef BRANCH_COST
  24 #define BRANCH_COST 1
  25 #endif
  26
  27 /* Macros to access the slots of a QUEUED rtx.
  28    Here rather than in rtl.h because only the expansion pass
  29    should ever encounter a QUEUED.  */
  30
  31 /* The variable for which an increment is queued.  */
  32 #define QUEUED_VAR(P) XEXP (P, 0)
  33 /* If the increment has been emitted, this is the insn
  34    that does the increment.  It is zero before the increment is emitted.
  35    If more than one insn is emitted, this is the first insn.  */
  36 #define QUEUED_INSN(P) XEXP (P, 1)
  37 /* If a pre-increment copy has been generated, this is the copy
  38    (it is a temporary reg).  Zero if no copy made yet.  */
  39 #define QUEUED_COPY(P) XEXP (P, 2)
  40 /* This is the body to use for the insn to do the increment.
  41    It is used to emit the increment.  */
  42 #define QUEUED_BODY(P) XEXP (P, 3)
  43 /* Next QUEUED in the queue.  */
  44 #define QUEUED_NEXT(P) XEXP (P, 4)
  45
  46 /* This is the 4th arg to `expand_expr'.
  47    EXPAND_STACK_PARM means we are possibly expanding a call param onto
  48    the stack.  Choosing a value of 2 isn't special;  It just allows
  49    some code optimization in store_expr.
  50    EXPAND_SUM means it is ok to return a PLUS rtx or MULT rtx.
  51    EXPAND_INITIALIZER is similar but also record any labels on forced_labels.
  52    EXPAND_CONST_ADDRESS means it is ok to return a MEM whose address
  53     is a constant that is not a legitimate address.
  54    EXPAND_WRITE means we are only going to write to the resulting rtx.
  55    EXPAND_MEMORY means we are interested in a memory result, even if
  56     the memory is constant and we could have propagated a constant value.  */
  57 enum expand_modifier {EXPAND_NORMAL = 0, EXPAND_STACK_PARM = 2, EXPAND_SUM,
  58                       EXPAND_CONST_ADDRESS, EXPAND_INITIALIZER, EXPAND_WRITE,
  59                       EXPAND_MEMORY};
  60
  61 /* Prevent the compiler from deferring stack pops.  See
  62    inhibit_defer_pop for more information.  */
  63 #define NO_DEFER_POP (inhibit_defer_pop += 1)
  64
  65 /* Allow the compiler to defer stack pops.  See inhibit_defer_pop for
  66    more information.  */
  67 #define OK_DEFER_POP (inhibit_defer_pop -= 1)
  68 \f
  69 enum direction {none, upward, downward};
  70
  71 #ifdef TREE_CODE /* Don't lose if tree.h not included.  */
  72 /* Structure to record the size of a sequence of arguments
  73    as the sum of a tree-expression and a constant.  This structure is
  74    also used to store offsets from the stack, which might be negative,
  75    so the variable part must be ssizetype, not sizetype.  */
  76
  77 struct args_size
  78 {
  79   HOST_WIDE_INT constant;
  80   tree var;
  81 };
  82
  83 /* Package up various arg related fields of struct args for
  84    locate_and_pad_parm.  */
  85 struct locate_and_pad_arg_data
  86 {
  87   /* Size of this argument on the stack, rounded up for any padding it
  88      gets.  If REG_PARM_STACK_SPACE is defined, then register parms are
  89      counted here, otherwise they aren't.  */
  90   struct args_size size;
  91   /* Offset of this argument from beginning of stack-args.  */
  92   struct args_size offset;
  93   /* Offset to the start of the stack slot.  Different from OFFSET
  94      if this arg pads downward.  */
  95   struct args_size slot_offset;
  96   /* The amount that the stack pointer needs to be adjusted to
  97      force alignment for the next argument.  */
  98   struct args_size alignment_pad;
  99 };
 100 #endif
 101
 102 /* Add the value of the tree INC to the `struct args_size' TO.  */
 103
 104 #define ADD_PARM_SIZE(TO, INC)                          \
 105 do {                                                    \
 106   tree inc = (INC);                                     \
 107   if (host_integerp (inc, 0))                           \
 108     (TO).constant += tree_low_cst (inc, 0);             \
 109   else if ((TO).var == 0)                               \
 110     (TO).var = convert (ssizetype, inc);                \
 111   else                                                  \
 112     (TO).var = size_binop (PLUS_EXPR, (TO).var,         \
 113                            convert (ssizetype, inc));   \
 114 } while (0)
 115
 116 #define SUB_PARM_SIZE(TO, DEC)                          \
 117 do {                                                    \
 118   tree dec = (DEC);                                     \
 119   if (host_integerp (dec, 0))                           \
 120     (TO).constant -= tree_low_cst (dec, 0);             \
 121   else if ((TO).var == 0)                               \
 122     (TO).var = size_binop (MINUS_EXPR, ssize_int (0),   \
 123                            convert (ssizetype, dec));   \
 124   else                                                  \
 125     (TO).var = size_binop (MINUS_EXPR, (TO).var,        \
 126                            convert (ssizetype, dec));   \
 127 } while (0)
 128
 129 /* Convert the implicit sum in a `struct args_size' into a tree
 130    of type ssizetype.  */
 131 #define ARGS_SIZE_TREE(SIZE)                                    \
 132 ((SIZE).var == 0 ? ssize_int ((SIZE).constant)                  \
 133  : size_binop (PLUS_EXPR, convert (ssizetype, (SIZE).var),      \
 134                ssize_int ((SIZE).constant)))
 135
 136 /* Convert the implicit sum in a `struct args_size' into an rtx.  */
 137 #define ARGS_SIZE_RTX(SIZE)                                     \
 138 ((SIZE).var == 0 ? GEN_INT ((SIZE).constant)                    \
 139  : expand_expr (ARGS_SIZE_TREE (SIZE), NULL_RTX, VOIDmode, 0))
 140
 141 /* Supply a default definition for FUNCTION_ARG_PADDING:
 142    usually pad upward, but pad short args downward on
 143    big-endian machines.  */
 144
 145 #ifndef FUNCTION_ARG_PADDING
 146 #define FUNCTION_ARG_PADDING(MODE, TYPE)                                \
 147   (! BYTES_BIG_ENDIAN                                                   \
 148    ? upward                                                             \
 149    : (((MODE) == BLKmode                                                \
 150        ? ((TYPE) && TREE_CODE (TYPE_SIZE (TYPE)) == INTEGER_CST         \
 151           && int_size_in_bytes (TYPE) < (PARM_BOUNDARY / BITS_PER_UNIT)) \
 152        : GET_MODE_BITSIZE (MODE) < PARM_BOUNDARY)                       \
 153       ? downward : upward))
 154 #endif
 155
 156 /* Supply a default definition for FUNCTION_ARG_BOUNDARY.  Normally, we let
 157    FUNCTION_ARG_PADDING, which also pads the length, handle any needed
 158    alignment.  */
 159
 160 #ifndef FUNCTION_ARG_BOUNDARY
 161 #define FUNCTION_ARG_BOUNDARY(MODE, TYPE)       PARM_BOUNDARY
 162 #endif
 163
 164 /* Define to nonzero if complex arguments should be split into their
 165    corresponding components.  */
 166 #ifndef SPLIT_COMPLEX_ARGS
 167 #define SPLIT_COMPLEX_ARGS 0
 168 #endif
 169 tree split_complex_types (tree);
 170 tree split_complex_values (tree);
 171
 172 /* Provide a default value for STRICT_ARGUMENT_NAMING.  */
 173 #ifndef STRICT_ARGUMENT_NAMING
 174 #define STRICT_ARGUMENT_NAMING 0
 175 #endif
 176
 177 /* Provide a default value for PRETEND_OUTGOING_VARARGS_NAMED.  */
 178 #ifdef SETUP_INCOMING_VARARGS
 179 #ifndef PRETEND_OUTGOING_VARARGS_NAMED
 180 #define PRETEND_OUTGOING_VARARGS_NAMED 1
 181 #endif
 182 #else
 183 /* It is an error to define PRETEND_OUTGOING_VARARGS_NAMED without
 184    defining SETUP_INCOMING_VARARGS.  */
 185 #define PRETEND_OUTGOING_VARARGS_NAMED 0
 186 #endif
 187
 188 /* Nonzero if we do not know how to pass TYPE solely in registers.  */
 189 extern bool default_must_pass_in_stack (enum machine_mode, tree);
 190 #ifndef MUST_PASS_IN_STACK
 191 #define MUST_PASS_IN_STACK(MODE,TYPE) default_must_pass_in_stack(MODE, TYPE)
 192 #endif
 193
 194 /* Nonzero if type TYPE should be returned in memory.
 195    Most machines can use the following default definition.  */
 196
 197 #ifndef RETURN_IN_MEMORY
 198 #define RETURN_IN_MEMORY(TYPE) (TYPE_MODE (TYPE) == BLKmode)
 199 #endif
 200
 201 /* Supply a default definition of STACK_SAVEAREA_MODE for emit_stack_save.
 202    Normally move_insn, so Pmode stack pointer.  */
 203
 204 #ifndef STACK_SAVEAREA_MODE
 205 #define STACK_SAVEAREA_MODE(LEVEL) Pmode
 206 #endif
 207
 208 /* Supply a default definition of STACK_SIZE_MODE for
 209    allocate_dynamic_stack_space.  Normally PLUS/MINUS, so word_mode.  */
 210
 211 #ifndef STACK_SIZE_MODE
 212 #define STACK_SIZE_MODE word_mode
 213 #endif
 214
 215 /* Provide default values for the macros controlling stack checking.  */
 216
 217 #ifndef STACK_CHECK_BUILTIN
 218 #define STACK_CHECK_BUILTIN 0
 219 #endif
 220
 221 /* The default interval is one page.  */
 222 #ifndef STACK_CHECK_PROBE_INTERVAL
 223 #define STACK_CHECK_PROBE_INTERVAL 4096
 224 #endif
 225
 226 /* The default is to do a store into the stack.  */
 227 #ifndef STACK_CHECK_PROBE_LOAD
 228 #define STACK_CHECK_PROBE_LOAD 0
 229 #endif
 230
 231 /* This value is arbitrary, but should be sufficient for most machines.  */
 232 #ifndef STACK_CHECK_PROTECT
 233 #define STACK_CHECK_PROTECT (75 * UNITS_PER_WORD)
 234 #endif
 235
 236 /* Make the maximum frame size be the largest we can and still only need
 237    one probe per function.  */
 238 #ifndef STACK_CHECK_MAX_FRAME_SIZE
 239 #define STACK_CHECK_MAX_FRAME_SIZE \
 240   (STACK_CHECK_PROBE_INTERVAL - UNITS_PER_WORD)
 241 #endif
 242
 243 /* This is arbitrary, but should be large enough everywhere.  */
 244 #ifndef STACK_CHECK_FIXED_FRAME_SIZE
 245 #define STACK_CHECK_FIXED_FRAME_SIZE (4 * UNITS_PER_WORD)
 246 #endif
 247
 248 /* Provide a reasonable default for the maximum size of an object to
 249    allocate in the fixed frame.  We may need to be able to make this
 250    controllable by the user at some point.  */
 251 #ifndef STACK_CHECK_MAX_VAR_SIZE
 252 #define STACK_CHECK_MAX_VAR_SIZE (STACK_CHECK_MAX_FRAME_SIZE / 100)
 253 #endif
 254 \f
 255 /* Functions from optabs.c, commonly used, and without need for the optabs
 256    tables:  */
 257
 258 /* Passed to expand_simple_binop and expand_binop to say which options
 259    to try to use if the requested operation can't be open-coded on the
 260    requisite mode.  Either OPTAB_LIB or OPTAB_LIB_WIDEN says try using
 261    a library call.  Either OPTAB_WIDEN or OPTAB_LIB_WIDEN says try
 262    using a wider mode.  OPTAB_MUST_WIDEN says try widening and don't
 263    try anything else.  */
 264
 265 enum optab_methods
 266 {
 267   OPTAB_DIRECT,
 268   OPTAB_LIB,
 269   OPTAB_WIDEN,
 270   OPTAB_LIB_WIDEN,
 271   OPTAB_MUST_WIDEN
 272 };
 273
 274 /* Generate code for a simple binary or unary operation.  "Simple" in
 275    this case means "can be unambiguously described by a (mode, code)
 276    pair and mapped to a single optab."  */
 277 extern rtx expand_simple_binop (enum machine_mode, enum rtx_code, rtx,
 278                                 rtx, rtx, int, enum optab_methods);
 279 extern rtx expand_simple_unop (enum machine_mode, enum rtx_code, rtx, rtx,
 280                                int);
 281
 282 /* Report whether the machine description contains an insn which can
 283    perform the operation described by CODE and MODE.  */
 284 extern int have_insn_for (enum rtx_code, enum machine_mode);
 285
 286 /* Emit code to make a call to a constant function or a library call.  */
 287 extern void emit_libcall_block (rtx, rtx, rtx, rtx);
 288
 289 /* Create but don't emit one rtl instruction to perform certain operations.
 290    Modes must match; operands must meet the operation's predicates.
 291    Likewise for subtraction and for just copying.
 292    These do not call protect_from_queue; caller must do so.  */
 293 extern rtx gen_add2_insn (rtx, rtx);
 294 extern rtx gen_add3_insn (rtx, rtx, rtx);
 295 extern rtx gen_sub2_insn (rtx, rtx);
 296 extern rtx gen_sub3_insn (rtx, rtx, rtx);
 297 extern rtx gen_move_insn (rtx, rtx);
 298 extern int have_add2_insn (rtx, rtx);
 299 extern int have_sub2_insn (rtx, rtx);
 300
 301 /* Emit a pair of rtl insns to compare two rtx's and to jump
 302    to a label if the comparison is true.  */
 303 extern void emit_cmp_and_jump_insns (rtx, rtx, enum rtx_code, rtx,
 304                                      enum machine_mode, int, rtx);
 305
 306 /* Generate code to indirectly jump to a location given in the rtx LOC.  */
 307 extern void emit_indirect_jump (rtx);
 308
 309 #ifdef HAVE_conditional_move
 310 /* Emit a conditional move operation.  */
 311 rtx emit_conditional_move (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 312                            rtx, rtx, enum machine_mode, int);
 313
 314 /* Return nonzero if the conditional move is supported.  */
 315 int can_conditionally_move_p (enum machine_mode mode);
 316
 317 #endif
 318 rtx emit_conditional_add (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 319                           rtx, rtx, enum machine_mode, int);
 320
 321 \f
 322 /* Functions from expmed.c:  */
 323
 324 /* Arguments MODE, RTX: return an rtx for the negation of that value.
 325    May emit insns.  */
 326 extern rtx negate_rtx (enum machine_mode, rtx);
 327
 328 /* Expand a logical AND operation.  */
 329 extern rtx expand_and (enum machine_mode, rtx, rtx, rtx);
 330
 331 /* Emit a store-flag operation.  */
 332 extern rtx emit_store_flag (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 333                             int, int);
 334
 335 /* Like emit_store_flag, but always succeeds.  */
 336 extern rtx emit_store_flag_force (rtx, enum rtx_code, rtx, rtx,
 337                                   enum machine_mode, int, int);
 338
 339 /* Functions from loop.c:  */
 340
 341 /* Given an insn and condition, return a canonical description of
 342    the test being made.  */
 343 extern rtx canonicalize_condition (rtx, rtx, int, rtx *, rtx);
 344
 345 /* Given a JUMP_INSN, return a canonical description of the test
 346    being made.  */
 347 extern rtx get_condition (rtx, rtx *);
 348
 349 /* Generate a conditional trap instruction.  */
 350 extern rtx gen_cond_trap (enum rtx_code, rtx, rtx, rtx);
 351 \f
 352 /* Functions from builtins.c:  */
 353 extern rtx expand_builtin (tree, rtx, rtx, enum machine_mode, int);
 354 extern void std_expand_builtin_va_start (tree, rtx);
 355 extern rtx std_expand_builtin_va_arg (tree, tree);
 356 extern rtx expand_builtin_va_arg (tree, tree);
 357 extern void default_init_builtins (void);
 358 extern rtx default_expand_builtin (tree, rtx, rtx, enum machine_mode, int);
 359 extern void expand_builtin_setjmp_setup (rtx, rtx);
 360 extern void expand_builtin_setjmp_receiver (rtx);
 361 extern void expand_builtin_longjmp (rtx, rtx);
 362 extern rtx expand_builtin_saveregs (void);
 363 extern void expand_builtin_trap (void);
 364 extern HOST_WIDE_INT get_varargs_alias_set (void);
 365 extern HOST_WIDE_INT get_frame_alias_set (void);
 366 extern void record_base_value (unsigned int, rtx, int);
 367 extern void record_alias_subset (HOST_WIDE_INT, HOST_WIDE_INT);
 368 extern HOST_WIDE_INT new_alias_set (void);
 369 extern int can_address_p (tree);
 370 \f
 371 /* Functions from expr.c:  */
 372
 373 /* This is run once per compilation to set up which modes can be used
 374    directly in memory and to initialize the block move optab.  */
 375 extern void init_expr_once (void);
 376
 377 /* This is run at the start of compiling a function.  */
 378 extern void init_expr (void);
 379
 380 /* This is run at the end of compiling a function.  */
 381 extern void finish_expr_for_function (void);
 382
 383 /* Use protect_from_queue to convert a QUEUED expression
 384    into something that you can put immediately into an instruction.  */
 385 extern rtx protect_from_queue (rtx, int);
 386
 387 /* Perform all the pending incrementations.  */
 388 extern void emit_queue (void);
 389
 390 /* Tell if something has a queued subexpression.  */
 391 extern int queued_subexp_p (rtx);
 392
 393 /* Emit some rtl insns to move data between rtx's, converting machine modes.
 394    Both modes must be floating or both fixed.  */
 395 extern void convert_move (rtx, rtx, int);
 396
 397 /* Convert an rtx to specified machine mode and return the result.  */
 398 extern rtx convert_to_mode (enum machine_mode, rtx, int);
 399
 400 /* Convert an rtx to MODE from OLDMODE and return the result.  */
 401 extern rtx convert_modes (enum machine_mode, enum machine_mode, rtx, int);
 402
 403 /* Emit code to move a block Y to a block X.  */
 404
 405 enum block_op_methods
 406 {
 407   BLOCK_OP_NORMAL,
 408   BLOCK_OP_NO_LIBCALL,
 409   BLOCK_OP_CALL_PARM
 410 };
 411
 412 extern void init_block_move_fn (const char *);
 413 extern void init_block_clear_fn (const char *);
 414
 415 extern rtx emit_block_move (rtx, rtx, rtx, enum block_op_methods);
 416
 417 /* Copy all or part of a value X into registers starting at REGNO.
 418    The number of registers to be filled is NREGS.  */
 419 extern void move_block_to_reg (int, rtx, int, enum machine_mode);
 420
 421 /* Copy all or part of a BLKmode value X out of registers starting at REGNO.
 422    The number of registers to be filled is NREGS.  */
 423 extern void move_block_from_reg (int, rtx, int);
 424
 425 /* Generate a non-consecutive group of registers represented by a PARALLEL.  */
 426 extern rtx gen_group_rtx (rtx);
 427
 428 /* Load a BLKmode value into non-consecutive registers represented by a
 429    PARALLEL.  */
 430 extern void emit_group_load (rtx, rtx, int);
 431
 432 /* Move a non-consecutive group of registers represented by a PARALLEL into
 433    a non-consecutive group of registers represented by a PARALLEL.  */
 434 extern void emit_group_move (rtx, rtx);
 435
 436 /* Store a BLKmode value from non-consecutive registers represented by a
 437    PARALLEL.  */
 438 extern void emit_group_store (rtx, rtx, int);
 439
 440 #ifdef TREE_CODE
 441 /* Copy BLKmode object from a set of registers.  */
 442 extern rtx copy_blkmode_from_reg (rtx, rtx, tree);
 443 #endif
 444
 445 /* Mark REG as holding a parameter for the next CALL_INSN.  */
 446 extern void use_reg (rtx *, rtx);
 447
 448 /* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
 449    for the next CALL_INSN.  */
 450 extern void use_regs (rtx *, int, int);
 451
 452 /* Mark a PARALLEL as holding a parameter for the next CALL_INSN.  */
 453 extern void use_group_regs (rtx *, rtx);
 454
 455 /* Write zeros through the storage of OBJECT.
 456    If OBJECT has BLKmode, SIZE is its length in bytes.  */
 457 extern rtx clear_storage (rtx, rtx);
 458
 459 /* Determine whether the LEN bytes can be moved by using several move
 460    instructions.  Return nonzero if a call to move_by_pieces should
 461    succeed.  */
 462 extern int can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
 463
 464 /* Return nonzero if it is desirable to store LEN bytes generated by
 465    CONSTFUN with several move instructions by store_by_pieces
 466    function.  CONSTFUNDATA is a pointer which will be passed as argument
 467    in every CONSTFUN call.
 468    ALIGN is maximum alignment we can assume.  */
 469 extern int can_store_by_pieces (unsigned HOST_WIDE_INT,
 470                                 rtx (*) (void *, HOST_WIDE_INT,
 471                                          enum machine_mode),
 472                                 void *, unsigned int);
 473
 474 /* Generate several move instructions to store LEN bytes generated by
 475    CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
 476    pointer which will be passed as argument in every CONSTFUN call.
 477    ALIGN is maximum alignment we can assume.
 478    Returns TO + LEN.  */
 479 extern rtx store_by_pieces (rtx, unsigned HOST_WIDE_INT,
 480                             rtx (*) (void *, HOST_WIDE_INT, enum machine_mode),
 481                             void *, unsigned int, int);
 482
 483 /* Emit insns to set X from Y.  */
 484 extern rtx emit_move_insn (rtx, rtx);
 485
 486 /* Emit insns to set X from Y, with no frills.  */
 487 extern rtx emit_move_insn_1 (rtx, rtx);
 488
 489 /* Push a block of length SIZE (perhaps variable)
 490    and return an rtx to address the beginning of the block.  */
 491 extern rtx push_block (rtx, int, int);
 492
 493 #ifdef TREE_CODE
 494 /* Generate code to push something onto the stack, given its mode and type.  */
 495 extern void emit_push_insn (rtx, enum machine_mode, tree, rtx, unsigned int,
 496                             int, rtx, int, rtx, rtx, int, rtx);
 497
 498 /* Expand an assignment that stores the value of FROM into TO.  */
 499 extern rtx expand_assignment (tree, tree, int, int);
 500
 501 /* Generate code for computing expression EXP,
 502    and storing the value into TARGET.
 503    If SUGGEST_REG is nonzero, copy the value through a register
 504    and return that register, if that is possible.  */
 505 extern rtx store_expr (tree, rtx, int);
 506 #endif
 507
 508 /* Given an rtx that may include add and multiply operations,
 509    generate them as insns and return a pseudo-reg containing the value.
 510    Useful after calling expand_expr with 1 as sum_ok.  */
 511 extern rtx force_operand (rtx, rtx);
 512
 513 /* Return an object on the placeholder list that matches EXP, a
 514    PLACEHOLDER_EXPR.  An object "matches" if it is of the type of the
 515    PLACEHOLDER_EXPR or a pointer type to it.  For further information, see
 516    tree.def.  If no such object is found, abort.  If PLIST is nonzero, it is
 517    a location which initially points to a starting location in the
 518    placeholder list (zero means start of the list) and where a pointer into
 519    the placeholder list at which the object is found is placed.  */
 520 extern tree find_placeholder (tree, tree *);
 521
 522 /* Generate code for computing expression EXP.
 523    An rtx for the computed value is returned.  The value is never null.
 524    In the case of a void EXP, const0_rtx is returned.  */
 525 extern rtx expand_expr (tree, rtx, enum machine_mode, enum expand_modifier);
 526
 527 /* At the start of a function, record that we have no previously-pushed
 528    arguments waiting to be popped.  */
 529 extern void init_pending_stack_adjust (void);
 530
 531 /* When exiting from function, if safe, clear out any pending stack adjust
 532    so the adjustment won't get done.  */
 533 extern void clear_pending_stack_adjust (void);
 534
 535 /* Pop any previously-pushed arguments that have not been popped yet.  */
 536 extern void do_pending_stack_adjust (void);
 537
 538 #ifdef TREE_CODE
 539 /* Return the tree node and offset if a given argument corresponds to
 540    a string constant.  */
 541 extern tree string_constant (tree, tree *);
 542
 543 /* Generate code to evaluate EXP and jump to LABEL if the value is zero.  */
 544 extern void jumpifnot (tree, rtx);
 545
 546 /* Generate code to evaluate EXP and jump to LABEL if the value is nonzero.  */
 547 extern void jumpif (tree, rtx);
 548
 549 /* Generate code to evaluate EXP and jump to IF_FALSE_LABEL if
 550    the result is zero, or IF_TRUE_LABEL if the result is one.  */
 551 extern void do_jump (tree, rtx, rtx);
 552 #endif
 553
 554 /* Generate rtl to compare two rtx's, will call emit_cmp_insn.  */
 555 extern rtx compare_from_rtx (rtx, rtx, enum rtx_code, int, enum machine_mode,
 556                              rtx);
 557 extern void do_compare_rtx_and_jump (rtx, rtx, enum rtx_code, int,
 558                                      enum machine_mode, rtx, rtx, rtx);
 559
 560 /* Two different ways of generating switch statements.  */
 561 extern int try_casesi (tree, tree, tree, tree, rtx, rtx);
 562 extern int try_tablejump (tree, tree, tree, tree, rtx, rtx);
 563
 564 /* Smallest number of adjacent cases before we use a jump table.
 565    XXX Should be a target hook.  */
 566 extern unsigned int case_values_threshold (void);
 567
 568 \f
 569 #ifdef TREE_CODE
 570 /* rtl.h and tree.h were included.  */
 571 /* Return an rtx for the size in bytes of the value of an expr.  */
 572 extern rtx expr_size (tree);
 573
 574 /* Return a wide integer for the size in bytes of the value of EXP, or -1
 575    if the size can vary or is larger than an integer.  */
 576 extern HOST_WIDE_INT int_expr_size (tree);
 577
 578 extern rtx lookup_static_chain (tree);
 579
 580 /* Convert a stack slot address ADDR valid in function FNDECL
 581    into an address valid in this function (using a static chain).  */
 582 extern rtx fix_lexical_addr (rtx, tree);
 583
 584 /* Return the address of the trampoline for entering nested fn FUNCTION.  */
 585 extern rtx trampoline_address (tree);
 586
 587 /* Return an rtx that refers to the value returned by a function
 588    in its original home.  This becomes invalid if any more code is emitted.  */
 589 extern rtx hard_function_value (tree, tree, int);
 590
 591 extern rtx prepare_call_address (rtx, tree, rtx *, int, int);
 592
 593 extern rtx expand_call (tree, rtx, int);
 594
 595 extern rtx expand_shift (enum tree_code, enum machine_mode, rtx, tree, rtx,
 596                          int);
 597 extern rtx expand_divmod (int, enum tree_code, enum machine_mode, rtx, rtx,
 598                           rtx, int);
 599 extern void locate_and_pad_parm (enum machine_mode, tree, int, int, tree,
 600                                  struct args_size *,
 601                                  struct locate_and_pad_arg_data *);
 602 extern rtx expand_inline_function (tree, tree, rtx, int, tree, rtx);
 603
 604 /* Return the CODE_LABEL rtx for a LABEL_DECL, creating it if necessary.  */
 605 extern rtx label_rtx (tree);
 606
 607 /* As label_rtx, but additionally the label is placed on the forced label
 608    list of its containing function (i.e. it is treated as reachable even
 609    if how is not obvious).  */
 610 extern rtx force_label_rtx (tree);
 611 #endif
 612
 613 /* Indicate how an input argument register was promoted.  */
 614 extern rtx promoted_input_arg (unsigned int, enum machine_mode *, int *);
 615
 616 /* Return an rtx like arg but sans any constant terms.
 617    Returns the original rtx if it has no constant terms.
 618    The constant terms are added and stored via a second arg.  */
 619 extern rtx eliminate_constant_term (rtx, rtx *);
 620
 621 /* Convert arg to a valid memory address for specified machine mode,
 622    by emitting insns to perform arithmetic if nec.  */
 623 extern rtx memory_address (enum machine_mode, rtx);
 624
 625 /* Like `memory_address' but pretent `flag_force_addr' is 0.  */
 626 extern rtx memory_address_noforce (enum machine_mode, rtx);
 627
 628 /* Set the alias set of MEM to SET.  */
 629 extern void set_mem_alias_set (rtx, HOST_WIDE_INT);
 630
 631 /* Set the alignment of MEM to ALIGN bits.  */
 632 extern void set_mem_align (rtx, unsigned int);
 633
 634 /* Set the expr for MEM to EXPR.  */
 635 extern void set_mem_expr (rtx, tree);
 636
 637 /* Set the offset for MEM to OFFSET.  */
 638 extern void set_mem_offset (rtx, rtx);
 639
 640 /* Set the size for MEM to SIZE.  */
 641 extern void set_mem_size (rtx, rtx);
 642
 643 /* Return a memory reference like MEMREF, but with its mode changed
 644    to MODE and its address changed to ADDR.
 645    (VOIDmode means don't change the mode.
 646    NULL for ADDR means don't change the address.)  */
 647 extern rtx change_address (rtx, enum machine_mode, rtx);
 648
 649 /* Return a memory reference like MEMREF, but with its mode changed
 650    to MODE and its address offset by OFFSET bytes.  */
 651 #define adjust_address(MEMREF, MODE, OFFSET) \
 652   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1)
 653
 654 /* Likewise, but the reference is not required to be valid.  */
 655 #define adjust_address_nv(MEMREF, MODE, OFFSET) \
 656   adjust_address_1 (MEMREF, MODE, OFFSET, 0, 1)
 657
 658 /* Return a memory reference like MEMREF, but with its mode changed
 659    to MODE and its address changed to ADDR, which is assumed to be
 660    increased by OFFSET bytes from MEMREF.  */
 661 #define adjust_automodify_address(MEMREF, MODE, ADDR, OFFSET) \
 662   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 1)
 663
 664 /* Likewise, but the reference is not required to be valid.  */
 665 #define adjust_automodify_address_nv(MEMREF, MODE, ADDR, OFFSET) \
 666   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 0)
 667
 668 extern rtx adjust_address_1 (rtx, enum machine_mode, HOST_WIDE_INT, int, int);
 669 extern rtx adjust_automodify_address_1 (rtx, enum machine_mode, rtx,
 670                                         HOST_WIDE_INT, int);
 671
 672 /* Return a memory reference like MEMREF, but whose address is changed by
 673    adding OFFSET, an RTX, to it.  POW2 is the highest power of two factor
 674    known to be in OFFSET (possibly 1).  */
 675 extern rtx offset_address (rtx, rtx, unsigned HOST_WIDE_INT);
 676
 677 /* Return a memory reference like MEMREF, but with its address changed to
 678    ADDR.  The caller is asserting that the actual piece of memory pointed
 679    to is the same, just the form of the address is being changed, such as
 680    by putting something into a register.  */
 681 extern rtx replace_equiv_address (rtx, rtx);
 682
 683 /* Likewise, but the reference is not required to be valid.  */
 684 extern rtx replace_equiv_address_nv (rtx, rtx);
 685
 686 /* Return a memory reference like MEMREF, but with its mode widened to
 687    MODE and adjusted by OFFSET.  */
 688 extern rtx widen_memory_access (rtx, enum machine_mode, HOST_WIDE_INT);
 689
 690 /* Return a memory reference like MEMREF, but which is known to have a
 691    valid address.  */
 692 extern rtx validize_mem (rtx);
 693
 694 #ifdef TREE_CODE
 695 /* Given REF, either a MEM or a REG, and T, either the type of X or
 696    the expression corresponding to REF, set RTX_UNCHANGING_P if
 697    appropriate.  */
 698 extern void maybe_set_unchanging (rtx, tree);
 699
 700 /* Given REF, a MEM, and T, either the type of X or the expression
 701    corresponding to REF, set the memory attributes.  OBJECTP is nonzero
 702    if we are making a new object of this type.  */
 703 extern void set_mem_attributes (rtx, tree, int);
 704
 705 /* Similar, except that BITPOS has not yet been applied to REF, so if
 706    we alter MEM_OFFSET according to T then we should subtract BITPOS
 707    expecting that it'll be added back in later.  */
 708 extern void set_mem_attributes_minus_bitpos (rtx, tree, int, HOST_WIDE_INT);
 709 #endif
 710
 711 /* Assemble the static constant template for function entry trampolines.  */
 712 extern rtx assemble_trampoline_template (void);
 713
 714 /* Given rtx, return new rtx whose address won't be affected by
 715    any side effects.  It has been copied to a new temporary reg.  */
 716 extern rtx stabilize (rtx);
 717
 718 /* Given an rtx, copy all regs it refers to into new temps
 719    and return a modified copy that refers to the new temps.  */
 720 extern rtx copy_all_regs (rtx);
 721
 722 /* Copy given rtx to a new temp reg and return that.  */
 723 extern rtx copy_to_reg (rtx);
 724
 725 /* Like copy_to_reg but always make the reg Pmode.  */
 726 extern rtx copy_addr_to_reg (rtx);
 727
 728 /* Like copy_to_reg but always make the reg the specified mode MODE.  */
 729 extern rtx copy_to_mode_reg (enum machine_mode, rtx);
 730
 731 /* Copy given rtx to given temp reg and return that.  */
 732 extern rtx copy_to_suggested_reg (rtx, rtx, enum machine_mode);
 733
 734 /* Copy a value to a register if it isn't already a register.
 735    Args are mode (in case value is a constant) and the value.  */
 736 extern rtx force_reg (enum machine_mode, rtx);
 737
 738 /* Return given rtx, copied into a new temp reg if it was in memory.  */
 739 extern rtx force_not_mem (rtx);
 740
 741 #ifdef TREE_CODE
 742 /* Return mode and signedness to use when object is promoted.  */
 743 extern enum machine_mode promote_mode (tree, enum machine_mode, int *, int);
 744 #endif
 745
 746 /* Remove some bytes from the stack.  An rtx says how many.  */
 747 extern void adjust_stack (rtx);
 748
 749 /* Add some bytes to the stack.  An rtx says how many.  */
 750 extern void anti_adjust_stack (rtx);
 751
 752 /* This enum is used for the following two functions.  */
 753 enum save_level {SAVE_BLOCK, SAVE_FUNCTION, SAVE_NONLOCAL};
 754
 755 /* Save the stack pointer at the specified level.  */
 756 extern void emit_stack_save (enum save_level, rtx *, rtx);
 757
 758 /* Restore the stack pointer from a save area of the specified level.  */
 759 extern void emit_stack_restore (enum save_level, rtx, rtx);
 760
 761 /* Allocate some space on the stack dynamically and return its address.  An rtx
 762    says how many bytes.  */
 763 extern rtx allocate_dynamic_stack_space (rtx, rtx, int);
 764
 765 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
 766    FIRST is a constant and size is a Pmode RTX.  These are offsets from the
 767    current stack pointer.  STACK_GROWS_DOWNWARD says whether to add or
 768    subtract from the stack.  If SIZE is constant, this is done
 769    with a fixed number of probes.  Otherwise, we must make a loop.  */
 770 extern void probe_stack_range (HOST_WIDE_INT, rtx);
 771
 772 /* Return an rtx that refers to the value returned by a library call
 773    in its original home.  This becomes invalid if any more code is emitted.  */
 774 extern rtx hard_libcall_value (enum machine_mode);
 775
 776 /* Given an rtx, return an rtx for a value rounded up to a multiple
 777    of STACK_BOUNDARY / BITS_PER_UNIT.  */
 778 extern rtx round_push (rtx);
 779
 780 /* Return the mode desired by operand N of a particular bitfield
 781    insert/extract insn, or MAX_MACHINE_MODE if no such insn is
 782    available.  */
 783
 784 enum extraction_pattern { EP_insv, EP_extv, EP_extzv };
 785 extern enum machine_mode
 786 mode_for_extraction (enum extraction_pattern, int);
 787
 788 extern rtx store_bit_field (rtx, unsigned HOST_WIDE_INT,
 789                             unsigned HOST_WIDE_INT, enum machine_mode, rtx,
 790                             HOST_WIDE_INT);
 791 extern rtx extract_bit_field (rtx, unsigned HOST_WIDE_INT,
 792                               unsigned HOST_WIDE_INT, int, rtx,
 793                               enum machine_mode, enum machine_mode,
 794                               HOST_WIDE_INT);
 795 extern rtx expand_mult (enum machine_mode, rtx, rtx, rtx, int);
 796 extern bool const_mult_add_overflow_p (rtx, rtx, rtx, enum machine_mode, int);
 797 extern rtx expand_mult_add (rtx, rtx, rtx, rtx,enum machine_mode, int);
 798 extern rtx expand_mult_highpart_adjust (enum machine_mode, rtx, rtx, rtx, rtx, int);
 799
 800 extern rtx assemble_static_space (unsigned HOST_WIDE_INT);
 801 extern int safe_from_p (rtx, tree, int);
 802
 803 /* Call this once to initialize the contents of the optabs
 804    appropriately for the current target machine.  */
 805 extern void init_optabs (void);
 806 extern void init_all_optabs (void);
 807
 808 /* Call this to initialize an optab function entry.  */
 809 extern rtx init_one_libfunc (const char *);
 810
 811 extern void do_jump_by_parts_equality_rtx (rtx, rtx, rtx);
 812 extern void do_jump_by_parts_greater_rtx (enum machine_mode, int, rtx, rtx,
 813                                           rtx, rtx);
 814
 815 #ifdef TREE_CODE   /* Don't lose if tree.h not included.  */
 816 extern void mark_seen_cases (tree, unsigned char *, HOST_WIDE_INT, int);
 817 #endif
 818
 819 extern int vector_mode_valid_p (enum machine_mode);
 820
 821 extern tree placeholder_list;