gcc/emit-rtl.h

   1 /* Exported functions from emit-rtl.c
   2    Copyright (C) 2004-2016 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 struct temp_slot;
  24 typedef struct temp_slot *temp_slot_p;
  25
  26 /* Information mainlined about RTL representation of incoming arguments.  */
  27 struct GTY(()) incoming_args {
  28   /* Number of bytes of args popped by function being compiled on its return.
  29      Zero if no bytes are to be popped.
  30      May affect compilation of return insn or of function epilogue.  */
  31   int pops_args;
  32
  33   /* If function's args have a fixed size, this is that size, in bytes.
  34      Otherwise, it is -1.
  35      May affect compilation of return insn or of function epilogue.  */
  36   int size;
  37
  38   /* # bytes the prologue should push and pretend that the caller pushed them.
  39      The prologue must do this, but only if parms can be passed in
  40      registers.  */
  41   int pretend_args_size;
  42
  43   /* This is the offset from the arg pointer to the place where the first
  44      anonymous arg can be found, if there is one.  */
  45   rtx arg_offset_rtx;
  46
  47   /* Quantities of various kinds of registers
  48      used for the current function's args.  */
  49   CUMULATIVE_ARGS info;
  50
  51   /* The arg pointer hard register, or the pseudo into which it was copied.  */
  52   rtx internal_arg_pointer;
  53 };
  54
  55
  56 /* Datastructures maintained for currently processed function in RTL form.  */
  57 struct GTY(()) rtl_data {
  58   struct expr_status expr;
  59   struct emit_status emit;
  60   struct varasm_status varasm;
  61   struct incoming_args args;
  62   struct function_subsections subsections;
  63   struct rtl_eh eh;
  64
  65   /* For function.c  */
  66
  67   /* # of bytes of outgoing arguments.  If ACCUMULATE_OUTGOING_ARGS is
  68      defined, the needed space is pushed by the prologue.  */
  69   int outgoing_args_size;
  70
  71   /* If nonzero, an RTL expression for the location at which the current
  72      function returns its result.  If the current function returns its
  73      result in a register, current_function_return_rtx will always be
  74      the hard register containing the result.  */
  75   rtx return_rtx;
  76   /* If nonxero, an RTL expression for the lcoation at which the current
  77      function returns bounds for its result.  */
  78   rtx return_bnd;
  79
  80   /* Vector of initial-value pairs.  Each pair consists of a pseudo
  81      register of approprite mode that stores the initial value a hard
  82      register REGNO, and that hard register itself.  */
  83   /* ??? This could be a VEC but there is currently no way to define an
  84          opaque VEC type.  */
  85   struct initial_value_struct *hard_reg_initial_vals;
  86
  87   /* A variable living at the top of the frame that holds a known value.
  88      Used for detecting stack clobbers.  */
  89   tree stack_protect_guard;
  90
  91   /* List (chain of INSN_LIST) of labels heading the current handlers for
  92      nonlocal gotos.  */
  93   rtx_insn_list *x_nonlocal_goto_handler_labels;
  94
  95   /* Label that will go on function epilogue.
  96      Jumping to this label serves as a "return" instruction
  97      on machines which require execution of the epilogue on all returns.  */
  98   rtx_code_label *x_return_label;
  99
 100   /* Label that will go on the end of function epilogue.
 101      Jumping to this label serves as a "naked return" instruction
 102      on machines which require execution of the epilogue on all returns.  */
 103   rtx_code_label *x_naked_return_label;
 104
 105   /* List (chain of EXPR_LISTs) of all stack slots in this function.
 106      Made for the sake of unshare_all_rtl.  */
 107   rtx_expr_list *x_stack_slot_list;
 108
 109   /* List of empty areas in the stack frame.  */
 110   struct frame_space *frame_space_list;
 111
 112   /* Place after which to insert the tail_recursion_label if we need one.  */
 113   rtx_note *x_stack_check_probe_note;
 114
 115   /* Location at which to save the argument pointer if it will need to be
 116      referenced.  There are two cases where this is done: if nonlocal gotos
 117      exist, or if vars stored at an offset from the argument pointer will be
 118      needed by inner routines.  */
 119   rtx x_arg_pointer_save_area;
 120
 121   /* Dynamic Realign Argument Pointer used for realigning stack.  */
 122   rtx drap_reg;
 123
 124   /* Offset to end of allocated area of stack frame.
 125      If stack grows down, this is the address of the last stack slot allocated.
 126      If stack grows up, this is the address for the next slot.  */
 127   HOST_WIDE_INT x_frame_offset;
 128
 129   /* Insn after which register parms and SAVE_EXPRs are born, if nonopt.  */
 130   rtx_insn *x_parm_birth_insn;
 131
 132   /* List of all used temporaries allocated, by level.  */
 133   vec<temp_slot_p, va_gc> *x_used_temp_slots;
 134
 135   /* List of available temp slots.  */
 136   struct temp_slot *x_avail_temp_slots;
 137
 138   /* Current nesting level for temporaries.  */
 139   int x_temp_slot_level;
 140
 141   /* The largest alignment needed on the stack, including requirement
 142      for outgoing stack alignment.  */
 143   unsigned int stack_alignment_needed;
 144
 145   /* Preferred alignment of the end of stack frame, which is preferred
 146      to call other functions.  */
 147   unsigned int preferred_stack_boundary;
 148
 149   /* The minimum alignment of parameter stack.  */
 150   unsigned int parm_stack_boundary;
 151
 152   /* The largest alignment of slot allocated on the stack.  */
 153   unsigned int max_used_stack_slot_alignment;
 154
 155   /* The stack alignment estimated before reload, with consideration of
 156      following factors:
 157      1. Alignment of local stack variables (max_used_stack_slot_alignment)
 158      2. Alignment requirement to call other functions
 159         (preferred_stack_boundary)
 160      3. Alignment of non-local stack variables but might be spilled in
 161         local stack.  */
 162   unsigned int stack_alignment_estimated;
 163
 164   /* For reorg.  */
 165
 166   /* Nonzero if function being compiled called builtin_return_addr or
 167      builtin_frame_address with nonzero count.  */
 168   bool accesses_prior_frames;
 169
 170   /* Nonzero if the function calls __builtin_eh_return.  */
 171   bool calls_eh_return;
 172
 173   /* Nonzero if function saves all registers, e.g. if it has a nonlocal
 174      label that can reach the exit block via non-exceptional paths. */
 175   bool saves_all_registers;
 176
 177   /* Nonzero if function being compiled has nonlocal gotos to parent
 178      function.  */
 179   bool has_nonlocal_goto;
 180
 181   /* Nonzero if function being compiled has an asm statement.  */
 182   bool has_asm_statement;
 183
 184   /* This bit is used by the exception handling logic.  It is set if all
 185      calls (if any) are sibling calls.  Such functions do not have to
 186      have EH tables generated, as they cannot throw.  A call to such a
 187      function, however, should be treated as throwing if any of its callees
 188      can throw.  */
 189   bool all_throwers_are_sibcalls;
 190
 191   /* Nonzero if stack limit checking should be enabled in the current
 192      function.  */
 193   bool limit_stack;
 194
 195   /* Nonzero if profiling code should be generated.  */
 196   bool profile;
 197
 198   /* Nonzero if the current function uses the constant pool.  */
 199   bool uses_const_pool;
 200
 201   /* Nonzero if the current function uses pic_offset_table_rtx.  */
 202   bool uses_pic_offset_table;
 203
 204   /* Nonzero if the current function needs an lsda for exception handling.  */
 205   bool uses_eh_lsda;
 206
 207   /* Set when the tail call has been produced.  */
 208   bool tail_call_emit;
 209
 210   /* Nonzero if code to initialize arg_pointer_save_area has been emitted.  */
 211   bool arg_pointer_save_area_init;
 212
 213   /* Nonzero if current function must be given a frame pointer.
 214      Set in reload1.c or lra-eliminations.c if anything is allocated
 215      on the stack there.  */
 216   bool frame_pointer_needed;
 217
 218   /* When set, expand should optimize for speed.  */
 219   bool maybe_hot_insn_p;
 220
 221   /* Nonzero if function stack realignment is needed.  This flag may be
 222      set twice: before and after reload.  It is set before reload wrt
 223      stack alignment estimation before reload.  It will be changed after
 224      reload if by then criteria of stack realignment is different.
 225      The value set after reload is the accurate one and is finalized.  */
 226   bool stack_realign_needed;
 227
 228   /* Nonzero if function stack realignment is tried.  This flag is set
 229      only once before reload.  It affects register elimination.  This
 230      is used to generate DWARF debug info for stack variables.  */
 231   bool stack_realign_tried;
 232
 233   /* Nonzero if function being compiled needs dynamic realigned
 234      argument pointer (drap) if stack needs realigning.  */
 235   bool need_drap;
 236
 237   /* Nonzero if function stack realignment estimation is done, namely
 238      stack_realign_needed flag has been set before reload wrt estimated
 239      stack alignment info.  */
 240   bool stack_realign_processed;
 241
 242   /* Nonzero if function stack realignment has been finalized, namely
 243      stack_realign_needed flag has been set and finalized after reload.  */
 244   bool stack_realign_finalized;
 245
 246   /* True if dbr_schedule has already been called for this function.  */
 247   bool dbr_scheduled_p;
 248
 249   /* True if current function can not throw.  Unlike
 250      TREE_NOTHROW (current_function_decl) it is set even for overwritable
 251      function where currently compiled version of it is nothrow.  */
 252   bool nothrow;
 253
 254   /* True if we performed shrink-wrapping for the current function.  */
 255   bool shrink_wrapped;
 256
 257   /* Nonzero if function being compiled doesn't modify the stack pointer
 258      (ignoring the prologue and epilogue).  This is only valid after
 259      pass_stack_ptr_mod has run.  */
 260   bool sp_is_unchanging;
 261
 262   /* Nonzero if function being compiled doesn't contain any calls
 263      (ignoring the prologue and epilogue).  This is set prior to
 264      local register allocation and is valid for the remaining
 265      compiler passes.  */
 266   bool is_leaf;
 267
 268   /* Nonzero if the function being compiled is a leaf function which only
 269      uses leaf registers.  This is valid after reload (specifically after
 270      sched2) and is useful only if the port defines LEAF_REGISTERS.  */
 271   bool uses_only_leaf_regs;
 272
 273   /* Nonzero if the function being compiled has undergone hot/cold partitioning
 274      (under flag_reorder_blocks_and_partition) and has at least one cold
 275      block.  */
 276   bool has_bb_partition;
 277
 278   /* Nonzero if the function being compiled has completed the bb reordering
 279      pass.  */
 280   bool bb_reorder_complete;
 281
 282   /* Like regs_ever_live, but 1 if a reg is set or clobbered from an
 283      asm.  Unlike regs_ever_live, elements of this array corresponding
 284      to eliminable regs (like the frame pointer) are set if an asm
 285      sets them.  */
 286   HARD_REG_SET asm_clobbers;
 287 };
 288
 289 #define return_label (crtl->x_return_label)
 290 #define naked_return_label (crtl->x_naked_return_label)
 291 #define stack_slot_list (crtl->x_stack_slot_list)
 292 #define parm_birth_insn (crtl->x_parm_birth_insn)
 293 #define frame_offset (crtl->x_frame_offset)
 294 #define stack_check_probe_note (crtl->x_stack_check_probe_note)
 295 #define arg_pointer_save_area (crtl->x_arg_pointer_save_area)
 296 #define used_temp_slots (crtl->x_used_temp_slots)
 297 #define avail_temp_slots (crtl->x_avail_temp_slots)
 298 #define temp_slot_level (crtl->x_temp_slot_level)
 299 #define nonlocal_goto_handler_labels (crtl->x_nonlocal_goto_handler_labels)
 300 #define frame_pointer_needed (crtl->frame_pointer_needed)
 301 #define stack_realign_fp (crtl->stack_realign_needed && !crtl->need_drap)
 302 #define stack_realign_drap (crtl->stack_realign_needed && crtl->need_drap)
 303
 304 extern GTY(()) struct rtl_data x_rtl;
 305
 306 /* Accessor to RTL datastructures.  We keep them statically allocated now since
 307    we never keep multiple functions.  For threaded compiler we might however
 308    want to do differently.  */
 309 #define crtl (&x_rtl)
 310
 311 /* Return whether two MEM_ATTRs are equal.  */
 312 bool mem_attrs_eq_p (const struct mem_attrs *, const struct mem_attrs *);
 313
 314 /* Set the alias set of MEM to SET.  */
 315 extern void set_mem_alias_set (rtx, alias_set_type);
 316
 317 /* Set the alignment of MEM to ALIGN bits.  */
 318 extern void set_mem_align (rtx, unsigned int);
 319
 320 /* Set the address space of MEM to ADDRSPACE.  */
 321 extern void set_mem_addr_space (rtx, addr_space_t);
 322
 323 /* Set the expr for MEM to EXPR.  */
 324 extern void set_mem_expr (rtx, tree);
 325
 326 /* Set the offset for MEM to OFFSET.  */
 327 extern void set_mem_offset (rtx, HOST_WIDE_INT);
 328
 329 /* Clear the offset recorded for MEM.  */
 330 extern void clear_mem_offset (rtx);
 331
 332 /* Set the size for MEM to SIZE.  */
 333 extern void set_mem_size (rtx, HOST_WIDE_INT);
 334
 335 /* Clear the size recorded for MEM.  */
 336 extern void clear_mem_size (rtx);
 337
 338 /* Set the attributes for MEM appropriate for a spill slot.  */
 339 extern void set_mem_attrs_for_spill (rtx);
 340 extern tree get_spill_slot_decl (bool);
 341
 342 /* Return a memory reference like MEMREF, but with its address changed to
 343    ADDR.  The caller is asserting that the actual piece of memory pointed
 344    to is the same, just the form of the address is being changed, such as
 345    by putting something into a register.  */
 346 extern rtx replace_equiv_address (rtx, rtx, bool = false);
 347
 348 /* Likewise, but the reference is not required to be valid.  */
 349 extern rtx replace_equiv_address_nv (rtx, rtx, bool = false);
 350
 351 extern rtx gen_blockage (void);
 352 extern rtvec gen_rtvec (int, ...);
 353 extern rtx copy_insn_1 (rtx);
 354 extern rtx copy_insn (rtx);
 355 extern rtx_insn *copy_delay_slot_insn (rtx_insn *);
 356 extern rtx gen_int_mode (HOST_WIDE_INT, machine_mode);
 357 extern rtx_insn *emit_copy_of_insn_after (rtx_insn *, rtx_insn *);
 358 extern void set_reg_attrs_from_value (rtx, rtx);
 359 extern void set_reg_attrs_for_parm (rtx, rtx);
 360 extern void set_reg_attrs_for_decl_rtl (tree t, rtx x);
 361 extern void adjust_reg_mode (rtx, machine_mode);
 362 extern int mem_expr_equal_p (const_tree, const_tree);
 363
 364 extern bool need_atomic_barrier_p (enum memmodel, bool);
 365
 366 /* Return the current sequence.  */
 367
 368 static inline struct sequence_stack *
 369 get_current_sequence (void)
 370 {
 371   return &crtl->emit.seq;
 372 }
 373
 374 /* Return the outermost sequence.  */
 375
 376 static inline struct sequence_stack *
 377 get_topmost_sequence (void)
 378 {
 379   struct sequence_stack *seq, *top;
 380
 381   seq = get_current_sequence ();
 382   do
 383     {
 384       top = seq;
 385       seq = seq->next;
 386     } while (seq);
 387   return top;
 388 }
 389
 390 /* Return the first insn of the current sequence or current function.  */
 391
 392 static inline rtx_insn *
 393 get_insns (void)
 394 {
 395   return get_current_sequence ()->first;
 396 }
 397
 398 /* Specify a new insn as the first in the chain.  */
 399
 400 static inline void
 401 set_first_insn (rtx_insn *insn)
 402 {
 403   gcc_checking_assert (!insn || !PREV_INSN (insn));
 404   get_current_sequence ()->first = insn;
 405 }
 406
 407 /* Return the last insn emitted in current sequence or current function.  */
 408
 409 static inline rtx_insn *
 410 get_last_insn (void)
 411 {
 412   return get_current_sequence ()->last;
 413 }
 414
 415 /* Specify a new insn as the last in the chain.  */
 416
 417 static inline void
 418 set_last_insn (rtx_insn *insn)
 419 {
 420   gcc_checking_assert (!insn || !NEXT_INSN (insn));
 421   get_current_sequence ()->last = insn;
 422 }
 423
 424 /* Return a number larger than any instruction's uid in this function.  */
 425
 426 static inline int
 427 get_max_uid (void)
 428 {
 429   return crtl->emit.x_cur_insn_uid;
 430 }
 431
 432 extern void set_decl_incoming_rtl (tree, rtx, bool);
 433
 434 /* Return a memory reference like MEMREF, but with its mode changed
 435    to MODE and its address changed to ADDR.
 436    (VOIDmode means don't change the mode.
 437    NULL for ADDR means don't change the address.)  */
 438 extern rtx change_address (rtx, machine_mode, rtx);
 439
 440 /* Return a memory reference like MEMREF, but with its mode changed
 441    to MODE and its address offset by OFFSET bytes.  */
 442 #define adjust_address(MEMREF, MODE, OFFSET) \
 443   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1, 0, 0)
 444
 445 /* Likewise, but the reference is not required to be valid.  */
 446 #define adjust_address_nv(MEMREF, MODE, OFFSET) \
 447   adjust_address_1 (MEMREF, MODE, OFFSET, 0, 1, 0, 0)
 448
 449 /* Return a memory reference like MEMREF, but with its mode changed
 450    to MODE and its address offset by OFFSET bytes.  Assume that it's
 451    for a bitfield and conservatively drop the underlying object if we
 452    cannot be sure to stay within its bounds.  */
 453 #define adjust_bitfield_address(MEMREF, MODE, OFFSET) \
 454   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1, 1, 0)
 455
 456 /* As for adjust_bitfield_address, but specify that the width of
 457    BLKmode accesses is SIZE bytes.  */
 458 #define adjust_bitfield_address_size(MEMREF, MODE, OFFSET, SIZE) \
 459   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1, 1, SIZE)
 460
 461 /* Likewise, but the reference is not required to be valid.  */
 462 #define adjust_bitfield_address_nv(MEMREF, MODE, OFFSET) \
 463   adjust_address_1 (MEMREF, MODE, OFFSET, 0, 1, 1, 0)
 464
 465 /* Return a memory reference like MEMREF, but with its mode changed
 466    to MODE and its address changed to ADDR, which is assumed to be
 467    increased by OFFSET bytes from MEMREF.  */
 468 #define adjust_automodify_address(MEMREF, MODE, ADDR, OFFSET) \
 469   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 1)
 470
 471 /* Likewise, but the reference is not required to be valid.  */
 472 #define adjust_automodify_address_nv(MEMREF, MODE, ADDR, OFFSET) \
 473   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 0)
 474
 475 extern rtx adjust_address_1 (rtx, machine_mode, HOST_WIDE_INT, int, int,
 476                              int, HOST_WIDE_INT);
 477 extern rtx adjust_automodify_address_1 (rtx, machine_mode, rtx,
 478                                         HOST_WIDE_INT, int);
 479
 480 /* Return a memory reference like MEMREF, but whose address is changed by
 481    adding OFFSET, an RTX, to it.  POW2 is the highest power of two factor
 482    known to be in OFFSET (possibly 1).  */
 483 extern rtx offset_address (rtx, rtx, unsigned HOST_WIDE_INT);
 484
 485 /* Given REF, a MEM, and T, either the type of X or the expression
 486    corresponding to REF, set the memory attributes.  OBJECTP is nonzero
 487    if we are making a new object of this type.  */
 488 extern void set_mem_attributes (rtx, tree, int);
 489
 490 /* Similar, except that BITPOS has not yet been applied to REF, so if
 491    we alter MEM_OFFSET according to T then we should subtract BITPOS
 492    expecting that it'll be added back in later.  */
 493 extern void set_mem_attributes_minus_bitpos (rtx, tree, int, HOST_WIDE_INT);
 494
 495 /* Return OFFSET if XEXP (MEM, 0) - OFFSET is known to be ALIGN
 496    bits aligned for 0 <= OFFSET < ALIGN / BITS_PER_UNIT, or
 497    -1 if not known.  */
 498 extern int get_mem_align_offset (rtx, unsigned int);
 499
 500 /* Return a memory reference like MEMREF, but with its mode widened to
 501    MODE and adjusted by OFFSET.  */
 502 extern rtx widen_memory_access (rtx, machine_mode, HOST_WIDE_INT);
 503
 504 #endif /* GCC_EMIT_RTL_H */