gcc/emit-rtl.h

   1 /* Exported functions from emit-rtl.cc
   2    Copyright (C) 2004-2022 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_EMIT_RTL_H
  21 #define GCC_EMIT_RTL_H
  22
  23 class temp_slot;
  24 typedef class temp_slot *temp_slot_p;
  25 class predefined_function_abi;
  26 namespace rtl_ssa { class function_info; }
  27
  28 /* Information mainlined about RTL representation of incoming arguments.  */
  29 struct GTY(()) incoming_args {
  30   /* Number of bytes of args popped by function being compiled on its return.
  31      Zero if no bytes are to be popped.
  32      May affect compilation of return insn or of function epilogue.  */
  33   poly_int64_pod pops_args;
  34
  35   /* If function's args have a fixed size, this is that size, in bytes.
  36      Otherwise, it is -1.
  37      May affect compilation of return insn or of function epilogue.  */
  38   poly_int64_pod size;
  39
  40   /* # bytes the prologue should push and pretend that the caller pushed them.
  41      The prologue must do this, but only if parms can be passed in
  42      registers.  */
  43   int pretend_args_size;
  44
  45   /* This is the offset from the arg pointer to the place where the first
  46      anonymous arg can be found, if there is one.  */
  47   rtx arg_offset_rtx;
  48
  49   /* Quantities of various kinds of registers
  50      used for the current function's args.  */
  51   CUMULATIVE_ARGS info;
  52
  53   /* The arg pointer hard register, or the pseudo into which it was copied.  */
  54   rtx internal_arg_pointer;
  55 };
  56
  57
  58 /* Datastructures maintained for currently processed function in RTL form.  */
  59 struct GTY(()) rtl_data {
  60   void init_stack_alignment ();
  61
  62   struct expr_status expr;
  63   struct emit_status emit;
  64   struct varasm_status varasm;
  65   struct incoming_args args;
  66   struct function_subsections subsections;
  67   struct rtl_eh eh;
  68
  69   /* The ABI of the function, i.e. the interface it presents to its callers.
  70      This is the ABI that should be queried to see which registers the
  71      function needs to save before it uses them.
  72
  73      Other functions (including those called by this function) might use
  74      different ABIs.  */
  75   const predefined_function_abi *GTY((skip)) abi;
  76
  77   rtl_ssa::function_info *GTY((skip)) ssa;
  78
  79   /* For function.cc  */
  80
  81   /* # of bytes of outgoing arguments.  If ACCUMULATE_OUTGOING_ARGS is
  82      defined, the needed space is pushed by the prologue.  */
  83   poly_int64_pod outgoing_args_size;
  84
  85   /* If nonzero, an RTL expression for the location at which the current
  86      function returns its result.  If the current function returns its
  87      result in a register, current_function_return_rtx will always be
  88      the hard register containing the result.  */
  89   rtx return_rtx;
  90
  91   /* Vector of initial-value pairs.  Each pair consists of a pseudo
  92      register of approprite mode that stores the initial value a hard
  93      register REGNO, and that hard register itself.  */
  94   /* ??? This could be a VEC but there is currently no way to define an
  95          opaque VEC type.  */
  96   struct initial_value_struct *hard_reg_initial_vals;
  97
  98   /* A variable living at the top of the frame that holds a known value.
  99      Used for detecting stack clobbers.  */
 100   tree stack_protect_guard;
 101
 102   /* The __stack_chk_guard variable or expression holding the stack
 103      protector canary value.  */
 104   tree stack_protect_guard_decl;
 105
 106   /* List (chain of INSN_LIST) of labels heading the current handlers for
 107      nonlocal gotos.  */
 108   rtx_insn_list *x_nonlocal_goto_handler_labels;
 109
 110   /* Label that will go on function epilogue.
 111      Jumping to this label serves as a "return" instruction
 112      on machines which require execution of the epilogue on all returns.  */
 113   rtx_code_label *x_return_label;
 114
 115   /* Label that will go on the end of function epilogue.
 116      Jumping to this label serves as a "naked return" instruction
 117      on machines which require execution of the epilogue on all returns.  */
 118   rtx_code_label *x_naked_return_label;
 119
 120   /* List (chain of EXPR_LISTs) of all stack slots in this function.
 121      Made for the sake of unshare_all_rtl.  */
 122   vec<rtx, va_gc> *x_stack_slot_list;
 123
 124   /* List of empty areas in the stack frame.  */
 125   class frame_space *frame_space_list;
 126
 127   /* Place after which to insert the tail_recursion_label if we need one.  */
 128   rtx_note *x_stack_check_probe_note;
 129
 130   /* Location at which to save the argument pointer if it will need to be
 131      referenced.  There are two cases where this is done: if nonlocal gotos
 132      exist, or if vars stored at an offset from the argument pointer will be
 133      needed by inner routines.  */
 134   rtx x_arg_pointer_save_area;
 135
 136   /* Dynamic Realign Argument Pointer used for realigning stack.  */
 137   rtx drap_reg;
 138
 139   /* Offset to end of allocated area of stack frame.
 140      If stack grows down, this is the address of the last stack slot allocated.
 141      If stack grows up, this is the address for the next slot.  */
 142   poly_int64_pod x_frame_offset;
 143
 144   /* Insn after which register parms and SAVE_EXPRs are born, if nonopt.  */
 145   rtx_insn *x_parm_birth_insn;
 146
 147   /* List of all used temporaries allocated, by level.  */
 148   vec<temp_slot_p, va_gc> *x_used_temp_slots;
 149
 150   /* List of available temp slots.  */
 151   class temp_slot *x_avail_temp_slots;
 152
 153   /* Current nesting level for temporaries.  */
 154   int x_temp_slot_level;
 155
 156   /* The largest alignment needed on the stack, including requirement
 157      for outgoing stack alignment.  */
 158   unsigned int stack_alignment_needed;
 159
 160   /* Preferred alignment of the end of stack frame, which is preferred
 161      to call other functions.  */
 162   unsigned int preferred_stack_boundary;
 163
 164   /* The minimum alignment of parameter stack.  */
 165   unsigned int parm_stack_boundary;
 166
 167   /* The largest alignment of slot allocated on the stack.  */
 168   unsigned int max_used_stack_slot_alignment;
 169
 170   /* The stack alignment estimated before reload, with consideration of
 171      following factors:
 172      1. Alignment of local stack variables (max_used_stack_slot_alignment)
 173      2. Alignment requirement to call other functions
 174         (preferred_stack_boundary)
 175      3. Alignment of non-local stack variables but might be spilled in
 176         local stack.  */
 177   unsigned int stack_alignment_estimated;
 178
 179   /* How many NOP insns to place at each function entry by default.  */
 180   unsigned short patch_area_size;
 181
 182   /* How far the real asm entry point is into this area.  */
 183   unsigned short patch_area_entry;
 184
 185   /* For reorg.  */
 186
 187   /* Nonzero if function being compiled called builtin_return_addr or
 188      builtin_frame_address with nonzero count.  */
 189   bool accesses_prior_frames;
 190
 191   /* Nonzero if the function calls __builtin_eh_return.  */
 192   bool calls_eh_return;
 193
 194   /* Nonzero if function saves all registers, e.g. if it has a nonlocal
 195      label that can reach the exit block via non-exceptional paths. */
 196   bool saves_all_registers;
 197
 198   /* Nonzero if function being compiled has nonlocal gotos to parent
 199      function.  */
 200   bool has_nonlocal_goto;
 201
 202   /* Nonzero if function being compiled has an asm statement.  */
 203   bool has_asm_statement;
 204
 205   /* This bit is used by the exception handling logic.  It is set if all
 206      calls (if any) are sibling calls.  Such functions do not have to
 207      have EH tables generated, as they cannot throw.  A call to such a
 208      function, however, should be treated as throwing if any of its callees
 209      can throw.  */
 210   bool all_throwers_are_sibcalls;
 211
 212   /* Nonzero if stack limit checking should be enabled in the current
 213      function.  */
 214   bool limit_stack;
 215
 216   /* Nonzero if profiling code should be generated.  */
 217   bool profile;
 218
 219   /* Nonzero if the current function uses the constant pool.  */
 220   bool uses_const_pool;
 221
 222   /* Nonzero if the current function uses pic_offset_table_rtx.  */
 223   bool uses_pic_offset_table;
 224
 225   /* Nonzero if the current function needs an lsda for exception handling.  */
 226   bool uses_eh_lsda;
 227
 228   /* Set when the tail call has been produced.  */
 229   bool tail_call_emit;
 230
 231   /* Nonzero if code to initialize arg_pointer_save_area has been emitted.  */
 232   bool arg_pointer_save_area_init;
 233
 234   /* Nonzero if current function must be given a frame pointer.
 235      Set in reload1.cc or lra-eliminations.cc if anything is allocated
 236      on the stack there.  */
 237   bool frame_pointer_needed;
 238
 239   /* When set, expand should optimize for speed.  */
 240   bool maybe_hot_insn_p;
 241
 242   /* Nonzero if function stack realignment is needed.  This flag may be
 243      set twice: before and after reload.  It is set before reload wrt
 244      stack alignment estimation before reload.  It will be changed after
 245      reload if by then criteria of stack realignment is different.
 246      The value set after reload is the accurate one and is finalized.  */
 247   bool stack_realign_needed;
 248
 249   /* Nonzero if function stack realignment is tried.  This flag is set
 250      only once before reload.  It affects register elimination.  This
 251      is used to generate DWARF debug info for stack variables.  */
 252   bool stack_realign_tried;
 253
 254   /* Nonzero if function being compiled needs dynamic realigned
 255      argument pointer (drap) if stack needs realigning.  */
 256   bool need_drap;
 257
 258   /* Nonzero if function stack realignment estimation is done, namely
 259      stack_realign_needed flag has been set before reload wrt estimated
 260      stack alignment info.  */
 261   bool stack_realign_processed;
 262
 263   /* Nonzero if function stack realignment has been finalized, namely
 264      stack_realign_needed flag has been set and finalized after reload.  */
 265   bool stack_realign_finalized;
 266
 267   /* True if dbr_schedule has already been called for this function.  */
 268   bool dbr_scheduled_p;
 269
 270   /* True if current function cannot throw.  Unlike
 271      TREE_NOTHROW (current_function_decl) it is set even for overwritable
 272      function where currently compiled version of it is nothrow.  */
 273   bool nothrow;
 274
 275   /* True if we performed shrink-wrapping for the current function.  */
 276   bool shrink_wrapped;
 277
 278   /* True if we performed shrink-wrapping for separate components for
 279      the current function.  */
 280   bool shrink_wrapped_separate;
 281
 282   /* Nonzero if function being compiled doesn't modify the stack pointer
 283      (ignoring the prologue and epilogue).  This is only valid after
 284      pass_stack_ptr_mod has run.  */
 285   bool sp_is_unchanging;
 286
 287   /* True if the stack pointer is clobbered by asm statement.  */
 288   bool sp_is_clobbered_by_asm;
 289
 290   /* Nonzero if function being compiled doesn't contain any calls
 291      (ignoring the prologue and epilogue).  This is set prior to
 292      register allocation in IRA and is valid for the remaining
 293      compiler passes.  */
 294   bool is_leaf;
 295
 296   /* Nonzero if the function being compiled is a leaf function which only
 297      uses leaf registers.  This is valid after reload (specifically after
 298      sched2) and is useful only if the port defines LEAF_REGISTERS.  */
 299   bool uses_only_leaf_regs;
 300
 301   /* Nonzero if the function being compiled has undergone hot/cold partitioning
 302      (under flag_reorder_blocks_and_partition) and has at least one cold
 303      block.  */
 304   bool has_bb_partition;
 305
 306   /* Nonzero if the function being compiled has completed the bb reordering
 307      pass.  */
 308   bool bb_reorder_complete;
 309
 310   /* Like regs_ever_live, but 1 if a reg is set or clobbered from an
 311      asm.  Unlike regs_ever_live, elements of this array corresponding
 312      to eliminable regs (like the frame pointer) are set if an asm
 313      sets them.  */
 314   HARD_REG_SET asm_clobbers;
 315
 316   /* All hard registers that need to be zeroed at the return of the routine.  */
 317   HARD_REG_SET must_be_zero_on_return;
 318
 319   /* The highest address seen during shorten_branches.  */
 320   int max_insn_address;
 321 };
 322
 323 #define return_label (crtl->x_return_label)
 324 #define naked_return_label (crtl->x_naked_return_label)
 325 #define stack_slot_list (crtl->x_stack_slot_list)
 326 #define parm_birth_insn (crtl->x_parm_birth_insn)
 327 #define frame_offset (crtl->x_frame_offset)
 328 #define stack_check_probe_note (crtl->x_stack_check_probe_note)
 329 #define arg_pointer_save_area (crtl->x_arg_pointer_save_area)
 330 #define used_temp_slots (crtl->x_used_temp_slots)
 331 #define avail_temp_slots (crtl->x_avail_temp_slots)
 332 #define temp_slot_level (crtl->x_temp_slot_level)
 333 #define nonlocal_goto_handler_labels (crtl->x_nonlocal_goto_handler_labels)
 334 #define frame_pointer_needed (crtl->frame_pointer_needed)
 335 #define stack_realign_fp (crtl->stack_realign_needed && !crtl->need_drap)
 336 #define stack_realign_drap (crtl->stack_realign_needed && crtl->need_drap)
 337
 338 extern GTY(()) struct rtl_data x_rtl;
 339
 340 /* Accessor to RTL datastructures.  We keep them statically allocated now since
 341    we never keep multiple functions.  For threaded compiler we might however
 342    want to do differently.  */
 343 #define crtl (&x_rtl)
 344
 345 /* Return whether two MEM_ATTRs are equal.  */
 346 bool mem_attrs_eq_p (const class mem_attrs *, const class mem_attrs *);
 347
 348 /* Set the alias set of MEM to SET.  */
 349 extern void set_mem_alias_set (rtx, alias_set_type);
 350
 351 /* Set the alignment of MEM to ALIGN bits.  */
 352 extern void set_mem_align (rtx, unsigned int);
 353
 354 /* Set the address space of MEM to ADDRSPACE.  */
 355 extern void set_mem_addr_space (rtx, addr_space_t);
 356
 357 /* Set the expr for MEM to EXPR.  */
 358 extern void set_mem_expr (rtx, tree);
 359
 360 /* Set the offset for MEM to OFFSET.  */
 361 extern void set_mem_offset (rtx, poly_int64);
 362
 363 /* Clear the offset recorded for MEM.  */
 364 extern void clear_mem_offset (rtx);
 365
 366 /* Set the size for MEM to SIZE.  */
 367 extern void set_mem_size (rtx, poly_int64);
 368
 369 /* Clear the size recorded for MEM.  */
 370 extern void clear_mem_size (rtx);
 371
 372 /* Set the attributes for MEM appropriate for a spill slot.  */
 373 extern void set_mem_attrs_for_spill (rtx);
 374 extern tree get_spill_slot_decl (bool);
 375
 376 /* Return a memory reference like MEMREF, but with its address changed to
 377    ADDR.  The caller is asserting that the actual piece of memory pointed
 378    to is the same, just the form of the address is being changed, such as
 379    by putting something into a register.  */
 380 extern rtx replace_equiv_address (rtx, rtx, bool = false);
 381
 382 /* Likewise, but the reference is not required to be valid.  */
 383 extern rtx replace_equiv_address_nv (rtx, rtx, bool = false);
 384
 385 extern rtx gen_blockage (void);
 386 extern rtvec gen_rtvec (int, ...);
 387 extern rtx copy_insn_1 (rtx);
 388 extern rtx copy_insn (rtx);
 389 extern rtx_insn *copy_delay_slot_insn (rtx_insn *);
 390 extern rtx gen_int_mode (poly_int64, machine_mode);
 391 extern rtx_insn *emit_copy_of_insn_after (rtx_insn *, rtx_insn *);
 392 extern void set_reg_attrs_from_value (rtx, rtx);
 393 extern void set_reg_attrs_for_parm (rtx, rtx);
 394 extern void set_reg_attrs_for_decl_rtl (tree t, rtx x);
 395 extern void adjust_reg_mode (rtx, machine_mode);
 396 extern int mem_expr_equal_p (const_tree, const_tree);
 397 extern rtx gen_int_shift_amount (machine_mode, poly_int64);
 398
 399 extern bool need_atomic_barrier_p (enum memmodel, bool);
 400
 401 /* Return the current sequence.  */
 402
 403 static inline struct sequence_stack *
 404 get_current_sequence (void)
 405 {
 406   return &crtl->emit.seq;
 407 }
 408
 409 /* Return the outermost sequence.  */
 410
 411 static inline struct sequence_stack *
 412 get_topmost_sequence (void)
 413 {
 414   struct sequence_stack *seq, *top;
 415
 416   seq = get_current_sequence ();
 417   do
 418     {
 419       top = seq;
 420       seq = seq->next;
 421     } while (seq);
 422   return top;
 423 }
 424
 425 /* Return the first insn of the current sequence or current function.  */
 426
 427 static inline rtx_insn *
 428 get_insns (void)
 429 {
 430   return get_current_sequence ()->first;
 431 }
 432
 433 /* Specify a new insn as the first in the chain.  */
 434
 435 static inline void
 436 set_first_insn (rtx_insn *insn)
 437 {
 438   gcc_checking_assert (!insn || !PREV_INSN (insn));
 439   get_current_sequence ()->first = insn;
 440 }
 441
 442 /* Return the last insn emitted in current sequence or current function.  */
 443
 444 static inline rtx_insn *
 445 get_last_insn (void)
 446 {
 447   return get_current_sequence ()->last;
 448 }
 449
 450 /* Specify a new insn as the last in the chain.  */
 451
 452 static inline void
 453 set_last_insn (rtx_insn *insn)
 454 {
 455   gcc_checking_assert (!insn || !NEXT_INSN (insn));
 456   get_current_sequence ()->last = insn;
 457 }
 458
 459 /* Return a number larger than any instruction's uid in this function.  */
 460
 461 static inline int
 462 get_max_uid (void)
 463 {
 464   return crtl->emit.x_cur_insn_uid;
 465 }
 466
 467 extern bool valid_for_const_vector_p (machine_mode, rtx);
 468 extern rtx gen_const_vec_duplicate (machine_mode, rtx);
 469 extern rtx gen_vec_duplicate (machine_mode, rtx);
 470
 471 extern rtx gen_const_vec_series (machine_mode, rtx, rtx);
 472 extern rtx gen_vec_series (machine_mode, rtx, rtx);
 473
 474 extern void set_decl_incoming_rtl (tree, rtx, bool);
 475
 476 /* Return a memory reference like MEMREF, but with its mode changed
 477    to MODE and its address changed to ADDR.
 478    (VOIDmode means don't change the mode.
 479    NULL for ADDR means don't change the address.)  */
 480 extern rtx change_address (rtx, machine_mode, rtx);
 481
 482 /* Return a memory reference like MEMREF, but with its mode changed
 483    to MODE and its address offset by OFFSET bytes.  */
 484 #define adjust_address(MEMREF, MODE, OFFSET) \
 485   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1, 0, 0)
 486
 487 /* Likewise, but the reference is not required to be valid.  */
 488 #define adjust_address_nv(MEMREF, MODE, OFFSET) \
 489   adjust_address_1 (MEMREF, MODE, OFFSET, 0, 1, 0, 0)
 490
 491 /* Return a memory reference like MEMREF, but with its mode changed
 492    to MODE and its address offset by OFFSET bytes.  Assume that it's
 493    for a bitfield and conservatively drop the underlying object if we
 494    cannot be sure to stay within its bounds.  */
 495 #define adjust_bitfield_address(MEMREF, MODE, OFFSET) \
 496   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1, 1, 0)
 497
 498 /* As for adjust_bitfield_address, but specify that the width of
 499    BLKmode accesses is SIZE bytes.  */
 500 #define adjust_bitfield_address_size(MEMREF, MODE, OFFSET, SIZE) \
 501   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1, 1, SIZE)
 502
 503 /* Likewise, but the reference is not required to be valid.  */
 504 #define adjust_bitfield_address_nv(MEMREF, MODE, OFFSET) \
 505   adjust_address_1 (MEMREF, MODE, OFFSET, 0, 1, 1, 0)
 506
 507 /* Return a memory reference like MEMREF, but with its mode changed
 508    to MODE and its address changed to ADDR, which is assumed to be
 509    increased by OFFSET bytes from MEMREF.  */
 510 #define adjust_automodify_address(MEMREF, MODE, ADDR, OFFSET) \
 511   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 1)
 512
 513 /* Likewise, but the reference is not required to be valid.  */
 514 #define adjust_automodify_address_nv(MEMREF, MODE, ADDR, OFFSET) \
 515   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 0)
 516
 517 extern rtx adjust_address_1 (rtx, machine_mode, poly_int64, int, int,
 518                              int, poly_int64);
 519 extern rtx adjust_automodify_address_1 (rtx, machine_mode, rtx,
 520                                         poly_int64, int);
 521
 522 /* Return a memory reference like MEMREF, but whose address is changed by
 523    adding OFFSET, an RTX, to it.  POW2 is the highest power of two factor
 524    known to be in OFFSET (possibly 1).  */
 525 extern rtx offset_address (rtx, rtx, unsigned HOST_WIDE_INT);
 526
 527 /* Given REF, a MEM, and T, either the type of X or the expression
 528    corresponding to REF, set the memory attributes.  OBJECTP is nonzero
 529    if we are making a new object of this type.  */
 530 extern void set_mem_attributes (rtx, tree, int);
 531
 532 /* Similar, except that BITPOS has not yet been applied to REF, so if
 533    we alter MEM_OFFSET according to T then we should subtract BITPOS
 534    expecting that it'll be added back in later.  */
 535 extern void set_mem_attributes_minus_bitpos (rtx, tree, int, poly_int64);
 536
 537 /* Return OFFSET if XEXP (MEM, 0) - OFFSET is known to be ALIGN
 538    bits aligned for 0 <= OFFSET < ALIGN / BITS_PER_UNIT, or
 539    -1 if not known.  */
 540 extern int get_mem_align_offset (rtx, unsigned int);
 541
 542 /* Return a memory reference like MEMREF, but with its mode widened to
 543    MODE and adjusted by OFFSET.  */
 544 extern rtx widen_memory_access (rtx, machine_mode, poly_int64);
 545
 546 extern void maybe_set_max_label_num (rtx_code_label *x);
 547
 548 #endif /* GCC_EMIT_RTL_H */