gcc/sched-int.h

   1 /* Instruction scheduling pass.  This file contains definitions used
   2    internally in the scheduler.
   3    Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   4    1999, 2000, 2001 Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING.  If not, write to the Free
  20 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  21 02111-1307, USA.  */
  22
  23 /* Forward declaration.  */
  24 struct ready_list;
  25
  26 /* Describe state of dependencies used during sched_analyze phase.  */
  27 struct deps
  28 {
  29   /* The *_insns and *_mems are paired lists.  Each pending memory operation
  30      will have a pointer to the MEM rtx on one list and a pointer to the
  31      containing insn on the other list in the same place in the list.  */
  32
  33   /* We can't use add_dependence like the old code did, because a single insn
  34      may have multiple memory accesses, and hence needs to be on the list
  35      once for each memory access.  Add_dependence won't let you add an insn
  36      to a list more than once.  */
  37
  38   /* An INSN_LIST containing all insns with pending read operations.  */
  39   rtx pending_read_insns;
  40
  41   /* An EXPR_LIST containing all MEM rtx's which are pending reads.  */
  42   rtx pending_read_mems;
  43
  44   /* An INSN_LIST containing all insns with pending write operations.  */
  45   rtx pending_write_insns;
  46
  47   /* An EXPR_LIST containing all MEM rtx's which are pending writes.  */
  48   rtx pending_write_mems;
  49
  50   /* Indicates the combined length of the two pending lists.  We must prevent
  51      these lists from ever growing too large since the number of dependencies
  52      produced is at least O(N*N), and execution time is at least O(4*N*N), as
  53      a function of the length of these pending lists.  */
  54   int pending_lists_length;
  55
  56   /* Length of the pending memory flush list. Large functions with no
  57      calls may build up extremely large lists.  */
  58   int pending_flush_length;
  59
  60   /* The last insn upon which all memory references must depend.
  61      This is an insn which flushed the pending lists, creating a dependency
  62      between it and all previously pending memory references.  This creates
  63      a barrier (or a checkpoint) which no memory reference is allowed to cross.
  64
  65      This includes all non constant CALL_INSNs.  When we do interprocedural
  66      alias analysis, this restriction can be relaxed.
  67      This may also be an INSN that writes memory if the pending lists grow
  68      too large.  */
  69   rtx last_pending_memory_flush;
  70
  71   /* A list of the last function calls we have seen.  We use a list to
  72      represent last function calls from multiple predecessor blocks.
  73      Used to prevent register lifetimes from expanding unnecessarily.  */
  74   rtx last_function_call;
  75
  76   /* A list of insns which use a pseudo register that does not already
  77      cross a call.  We create dependencies between each of those insn
  78      and the next call insn, to ensure that they won't cross a call after
  79      scheduling is done.  */
  80   rtx sched_before_next_call;
  81
  82   /* Used to keep post-call psuedo/hard reg movements together with
  83      the call.  */
  84   bool in_post_call_group_p;
  85
  86   /* The maximum register number for the following arrays.  Before reload
  87      this is max_reg_num; after reload it is FIRST_PSEUDO_REGISTER.  */
  88   int max_reg;
  89
  90   /* Element N is the next insn that sets (hard or pseudo) register
  91      N within the current basic block; or zero, if there is no
  92      such insn.  Needed for new registers which may be introduced
  93      by splitting insns.  */
  94   struct deps_reg
  95     {
  96       rtx uses;
  97       rtx sets;
  98       rtx clobbers;
  99       int uses_length;
 100       int clobbers_length;
 101     } *reg_last;
 102
 103   /* Element N is set for each register that has any non-zero element
 104      in reg_last[N].{uses,sets,clobbers}.  */
 105   regset_head reg_last_in_use;
 106 };
 107
 108 /* This structure holds some state of the current scheduling pass, and
 109    contains some function pointers that abstract out some of the non-generic
 110    functionality from functions such as schedule_block or schedule_insn.
 111    There is one global variable, current_sched_info, which points to the
 112    sched_info structure currently in use.  */
 113 struct sched_info
 114 {
 115   /* Add all insns that are initially ready to the ready list.  Called once
 116      before scheduling a set of insns.  */
 117   void (*init_ready_list) PARAMS ((struct ready_list *));
 118   /* Called after taking an insn from the ready list.  Returns nonzero if
 119      this insn can be scheduled, nonzero if we should silently discard it.  */
 120   int (*can_schedule_ready_p) PARAMS ((rtx));
 121   /* Return nonzero if there are more insns that should be scheduled.  */
 122   int (*schedule_more_p) PARAMS ((void));
 123   /* Called after an insn has all its dependencies resolved.  Return nonzero
 124      if it should be moved to the ready list or the queue, or zero if we
 125      should silently discard it.  */
 126   int (*new_ready) PARAMS ((rtx));
 127   /* Compare priority of two insns.  Return a positive number if the second
 128      insn is to be preferred for scheduling, and a negative one if the first
 129      is to be preferred.  Zero if they are equally good.  */
 130   int (*rank) PARAMS ((rtx, rtx));
 131   /* Return a string that contains the insn uid and optionally anything else
 132      necessary to identify this insn in an output.  It's valid to use a
 133      static buffer for this.  The ALIGNED parameter should cause the string
 134      to be formatted so that multiple output lines will line up nicely.  */
 135   const char *(*print_insn) PARAMS ((rtx, int));
 136   /* Return nonzero if an insn should be included in priority
 137      calculations.  */
 138   int (*contributes_to_priority) PARAMS ((rtx, rtx));
 139   /* Called when computing dependencies for a JUMP_INSN.  This function
 140      should store the set of registers that must be considered as set by
 141      the jump in the regset.  */
 142   void (*compute_jump_reg_dependencies) PARAMS ((rtx, regset));
 143
 144   /* The boundaries of the set of insns to be scheduled.  */
 145   rtx prev_head, next_tail;
 146
 147   /* Filled in after the schedule is finished; the first and last scheduled
 148      insns.  */
 149   rtx head, tail;
 150
 151   /* If nonzero, enables an additional sanity check in schedule_block.  */
 152   unsigned int queue_must_finish_empty:1;
 153   /* Nonzero if we should use cselib for better alias analysis.  This
 154      must be 0 if the dependency information is used after sched_analyze
 155      has completed, e.g. if we're using it to initialize state for successor
 156      blocks in region scheduling.  */
 157   unsigned int use_cselib:1;
 158 };
 159
 160 extern struct sched_info *current_sched_info;
 161
 162 /* Indexed by INSN_UID, the collection of all data associated with
 163    a single instruction.  */
 164
 165 struct haifa_insn_data
 166 {
 167   /* A list of insns which depend on the instruction.  Unlike LOG_LINKS,
 168      it represents forward dependencies.  */
 169   rtx depend;
 170
 171   /* The line number note in effect for each insn.  For line number
 172      notes, this indicates whether the note may be reused.  */
 173   rtx line_note;
 174
 175   /* Logical uid gives the original ordering of the insns.  */
 176   int luid;
 177
 178   /* A priority for each insn.  */
 179   int priority;
 180
 181   /* The number of incoming edges in the forward dependency graph.
 182      As scheduling proceds, counts are decreased.  An insn moves to
 183      the ready queue when its counter reaches zero.  */
 184   int dep_count;
 185
 186   /* An encoding of the blockage range function.  Both unit and range
 187      are coded.  */
 188   unsigned int blockage;
 189
 190   /* Number of instructions referring to this insn.  */
 191   int ref_count;
 192
 193   /* The minimum clock tick at which the insn becomes ready.  This is
 194      used to note timing constraints for the insns in the pending list.  */
 195   int tick;
 196
 197   short cost;
 198
 199   /* An encoding of the function units used.  */
 200   short units;
 201
 202   /* This weight is an estimation of the insn's contribution to
 203      register pressure.  */
 204   short reg_weight;
 205
 206   /* Some insns (e.g. call) are not allowed to move across blocks.  */
 207   unsigned int cant_move : 1;
 208
 209   /* Set if there's DEF-USE dependence between some speculatively
 210      moved load insn and this one.  */
 211   unsigned int fed_by_spec_load : 1;
 212   unsigned int is_load_insn : 1;
 213
 214   /* Nonzero if priority has been computed already.  */
 215   unsigned int priority_known : 1;
 216 };
 217
 218 extern struct haifa_insn_data *h_i_d;
 219
 220 /* Accessor macros for h_i_d.  There are more in haifa-sched.c and
 221    sched-rgn.c.  */
 222 #define INSN_DEPEND(INSN)       (h_i_d[INSN_UID (INSN)].depend)
 223 #define INSN_LUID(INSN)         (h_i_d[INSN_UID (INSN)].luid)
 224 #define CANT_MOVE(insn)         (h_i_d[INSN_UID (insn)].cant_move)
 225 #define INSN_DEP_COUNT(INSN)    (h_i_d[INSN_UID (INSN)].dep_count)
 226 #define INSN_PRIORITY(INSN)     (h_i_d[INSN_UID (INSN)].priority)
 227 #define INSN_PRIORITY_KNOWN(INSN) (h_i_d[INSN_UID (INSN)].priority_known)
 228 #define INSN_COST(INSN)         (h_i_d[INSN_UID (INSN)].cost)
 229 #define INSN_UNIT(INSN)         (h_i_d[INSN_UID (INSN)].units)
 230 #define INSN_REG_WEIGHT(INSN)   (h_i_d[INSN_UID (INSN)].reg_weight)
 231
 232 #define INSN_BLOCKAGE(INSN)     (h_i_d[INSN_UID (INSN)].blockage)
 233 #define UNIT_BITS               5
 234 #define BLOCKAGE_MASK           ((1 << BLOCKAGE_BITS) - 1)
 235 #define ENCODE_BLOCKAGE(U, R)                   \
 236   (((U) << BLOCKAGE_BITS                        \
 237     | MIN_BLOCKAGE_COST (R)) << BLOCKAGE_BITS   \
 238    | MAX_BLOCKAGE_COST (R))
 239 #define UNIT_BLOCKED(B)         ((B) >> (2 * BLOCKAGE_BITS))
 240 #define BLOCKAGE_RANGE(B)                                                \
 241   (((((B) >> BLOCKAGE_BITS) & BLOCKAGE_MASK) << (HOST_BITS_PER_INT / 2)) \
 242    | ((B) & BLOCKAGE_MASK))
 243
 244 /* Encodings of the `<name>_unit_blockage_range' function.  */
 245 #define MIN_BLOCKAGE_COST(R) ((R) >> (HOST_BITS_PER_INT / 2))
 246 #define MAX_BLOCKAGE_COST(R) ((R) & ((1 << (HOST_BITS_PER_INT / 2)) - 1))
 247
 248 extern FILE *sched_dump;
 249 extern int sched_verbose;
 250
 251 #ifndef __GNUC__
 252 #define __inline
 253 #endif
 254
 255 #ifndef HAIFA_INLINE
 256 #define HAIFA_INLINE __inline
 257 #endif
 258
 259 /* Functions in sched-vis.c.  */
 260 extern void init_target_units PARAMS ((void));
 261 extern void insn_print_units PARAMS ((rtx));
 262 extern void init_block_visualization PARAMS ((void));
 263 extern void print_block_visualization PARAMS ((const char *));
 264 extern void visualize_scheduled_insns PARAMS ((int));
 265 extern void visualize_no_unit PARAMS ((rtx));
 266 extern void visualize_stall_cycles PARAMS ((int));
 267 extern void visualize_alloc PARAMS ((void));
 268 extern void visualize_free PARAMS ((void));
 269
 270 /* Functions in sched-deps.c.  */
 271 extern void add_dependence PARAMS ((rtx, rtx, enum reg_note));
 272 extern void add_insn_mem_dependence PARAMS ((struct deps *, rtx *, rtx *, rtx,
 273                                              rtx));
 274 extern void sched_analyze PARAMS ((struct deps *, rtx, rtx));
 275 extern void init_deps PARAMS ((struct deps *));
 276 extern void free_deps PARAMS ((struct deps *));
 277 extern void init_deps_global PARAMS ((void));
 278 extern void finish_deps_global PARAMS ((void));
 279 extern void compute_forward_dependences PARAMS ((rtx, rtx));
 280 extern rtx find_insn_list PARAMS ((rtx, rtx));
 281 extern void init_dependency_caches PARAMS ((int));
 282 extern void free_dependency_caches PARAMS ((void));
 283
 284 /* Functions in haifa-sched.c.  */
 285 extern void get_block_head_tail PARAMS ((int, rtx *, rtx *));
 286 extern int no_real_insns_p PARAMS ((rtx, rtx));
 287
 288 extern void rm_line_notes PARAMS ((rtx, rtx));
 289 extern void save_line_notes PARAMS ((int, rtx, rtx));
 290 extern void restore_line_notes PARAMS ((rtx, rtx));
 291 extern void rm_redundant_line_notes PARAMS ((void));
 292 extern void rm_other_notes PARAMS ((rtx, rtx));
 293
 294 extern int insn_issue_delay PARAMS ((rtx));
 295 extern int set_priorities PARAMS ((rtx, rtx));
 296
 297 extern void schedule_block PARAMS ((int, int));
 298 extern void sched_init PARAMS ((FILE *));
 299 extern void sched_finish PARAMS ((void));
 300
 301 extern void ready_add PARAMS ((struct ready_list *, rtx));
 302
 303 /* The following are exported for the benefit of debugging functions.  It
 304    would be nicer to keep them private to haifa-sched.c.  */
 305 extern int insn_unit PARAMS ((rtx));
 306 extern int insn_cost PARAMS ((rtx, rtx, rtx));
 307 extern rtx get_unit_last_insn PARAMS ((int));
 308 extern int actual_hazard_this_instance PARAMS ((int, int, rtx, int, int));
 309