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 /* Pointer to data describing the current DFA state. */ 24 extern state_t curr_state; 25 26 /* Forward declaration. */ 27 struct ready_list; 28 29 /* Describe state of dependencies used during sched_analyze phase. */ 30 struct deps 31 { 32 /* The *_insns and *_mems are paired lists. Each pending memory operation 33 will have a pointer to the MEM rtx on one list and a pointer to the 34 containing insn on the other list in the same place in the list. */ 35 36 /* We can't use add_dependence like the old code did, because a single insn 37 may have multiple memory accesses, and hence needs to be on the list 38 once for each memory access. Add_dependence won't let you add an insn 39 to a list more than once. */ 40 41 /* An INSN_LIST containing all insns with pending read operations. */ 42 rtx pending_read_insns; 43 44 /* An EXPR_LIST containing all MEM rtx's which are pending reads. */ 45 rtx pending_read_mems; 46 47 /* An INSN_LIST containing all insns with pending write operations. */ 48 rtx pending_write_insns; 49 50 /* An EXPR_LIST containing all MEM rtx's which are pending writes. */ 51 rtx pending_write_mems; 52 53 /* Indicates the combined length of the two pending lists. We must prevent 54 these lists from ever growing too large since the number of dependencies 55 produced is at least O(N*N), and execution time is at least O(4*N*N), as 56 a function of the length of these pending lists. */ 57 int pending_lists_length; 58 59 /* Length of the pending memory flush list. Large functions with no 60 calls may build up extremely large lists. */ 61 int pending_flush_length; 62 63 /* The last insn upon which all memory references must depend. 64 This is an insn which flushed the pending lists, creating a dependency 65 between it and all previously pending memory references. This creates 66 a barrier (or a checkpoint) which no memory reference is allowed to cross. 67 68 This includes all non constant CALL_INSNs. When we do interprocedural 69 alias analysis, this restriction can be relaxed. 70 This may also be an INSN that writes memory if the pending lists grow 71 too large. */ 72 rtx last_pending_memory_flush; 73 74 /* A list of the last function calls we have seen. We use a list to 75 represent last function calls from multiple predecessor blocks. 76 Used to prevent register lifetimes from expanding unnecessarily. */ 77 rtx last_function_call; 78 79 /* A list of insns which use a pseudo register that does not already 80 cross a call. We create dependencies between each of those insn 81 and the next call insn, to ensure that they won't cross a call after 82 scheduling is done. */ 83 rtx sched_before_next_call; 84 85 /* Used to keep post-call psuedo/hard reg movements together with 86 the call. */ 87 bool in_post_call_group_p; 88 89 /* Set to the tail insn of the outermost libcall block. 90 91 When nonzero, we will mark each insn processed by sched_analyze_insn 92 with SCHED_GROUP_P to ensure libcalls are scheduled as a unit. */ 93 rtx libcall_block_tail_insn; 94 95 /* The maximum register number for the following arrays. Before reload 96 this is max_reg_num; after reload it is FIRST_PSEUDO_REGISTER. */ 97 int max_reg; 98 99 /* Element N is the next insn that sets (hard or pseudo) register 100 N within the current basic block; or zero, if there is no 101 such insn. Needed for new registers which may be introduced 102 by splitting insns. */ 103 struct deps_reg 104 { 105 rtx uses; 106 rtx sets; 107 rtx clobbers; 108 int uses_length; 109 int clobbers_length; 110 } *reg_last; 111 112 /* Element N is set for each register that has any nonzero element 113 in reg_last[N].{uses,sets,clobbers}. */ 114 regset_head reg_last_in_use; 115 116 /* Element N is set for each register that is conditionally set. */ 117 regset_head reg_conditional_sets; 118 }; 119 120 /* This structure holds some state of the current scheduling pass, and 121 contains some function pointers that abstract out some of the non-generic 122 functionality from functions such as schedule_block or schedule_insn. 123 There is one global variable, current_sched_info, which points to the 124 sched_info structure currently in use. */ 125 struct sched_info 126 { 127 /* Add all insns that are initially ready to the ready list. Called once 128 before scheduling a set of insns. */ 129 void (*init_ready_list) PARAMS ((struct ready_list *)); 130 /* Called after taking an insn from the ready list. Returns nonzero if 131 this insn can be scheduled, nonzero if we should silently discard it. */ 132 int (*can_schedule_ready_p) PARAMS ((rtx)); 133 /* Return nonzero if there are more insns that should be scheduled. */ 134 int (*schedule_more_p) PARAMS ((void)); 135 /* Called after an insn has all its dependencies resolved. Return nonzero 136 if it should be moved to the ready list or the queue, or zero if we 137 should silently discard it. */ 138 int (*new_ready) PARAMS ((rtx)); 139 /* Compare priority of two insns. Return a positive number if the second 140 insn is to be preferred for scheduling, and a negative one if the first 141 is to be preferred. Zero if they are equally good. */ 142 int (*rank) PARAMS ((rtx, rtx)); 143 /* Return a string that contains the insn uid and optionally anything else 144 necessary to identify this insn in an output. It's valid to use a 145 static buffer for this. The ALIGNED parameter should cause the string 146 to be formatted so that multiple output lines will line up nicely. */ 147 const char *(*print_insn) PARAMS ((rtx, int)); 148 /* Return nonzero if an insn should be included in priority 149 calculations. */ 150 int (*contributes_to_priority) PARAMS ((rtx, rtx)); 151 /* Called when computing dependencies for a JUMP_INSN. This function 152 should store the set of registers that must be considered as used 153 and the set of registers that must be considered as set by the jump. */ 154 void (*compute_jump_reg_dependencies) PARAMS ((rtx, regset, regset, regset)); 155 156 /* The boundaries of the set of insns to be scheduled. */ 157 rtx prev_head, next_tail; 158 159 /* Filled in after the schedule is finished; the first and last scheduled 160 insns. */ 161 rtx head, tail; 162 163 /* If nonzero, enables an additional sanity check in schedule_block. */ 164 unsigned int queue_must_finish_empty:1; 165 /* Nonzero if we should use cselib for better alias analysis. This 166 must be 0 if the dependency information is used after sched_analyze 167 has completed, e.g. if we're using it to initialize state for successor 168 blocks in region scheduling. */ 169 unsigned int use_cselib:1; 170 }; 171 172 extern struct sched_info *current_sched_info; 173 174 /* Indexed by INSN_UID, the collection of all data associated with 175 a single instruction. */ 176 177 struct haifa_insn_data 178 { 179 /* A list of insns which depend on the instruction. Unlike LOG_LINKS, 180 it represents forward dependencies. */ 181 rtx depend; 182 183 /* The line number note in effect for each insn. For line number 184 notes, this indicates whether the note may be reused. */ 185 rtx line_note; 186 187 /* Logical uid gives the original ordering of the insns. */ 188 int luid; 189 190 /* A priority for each insn. */ 191 int priority; 192 193 /* The number of incoming edges in the forward dependency graph. 194 As scheduling proceds, counts are decreased. An insn moves to 195 the ready queue when its counter reaches zero. */ 196 int dep_count; 197 198 /* An encoding of the blockage range function. Both unit and range 199 are coded. This member is used only for old pipeline interface. */ 200 unsigned int blockage; 201 202 /* Number of instructions referring to this insn. */ 203 int ref_count; 204 205 /* The minimum clock tick at which the insn becomes ready. This is 206 used to note timing constraints for the insns in the pending list. */ 207 int tick; 208 209 short cost; 210 211 /* An encoding of the function units used. This member is used only 212 for old pipeline interface. */ 213 short units; 214 215 /* This weight is an estimation of the insn's contribution to 216 register pressure. */ 217 short reg_weight; 218 219 /* Some insns (e.g. call) are not allowed to move across blocks. */ 220 unsigned int cant_move : 1; 221 222 /* Set if there's DEF-USE dependence between some speculatively 223 moved load insn and this one. */ 224 unsigned int fed_by_spec_load : 1; 225 unsigned int is_load_insn : 1; 226 227 /* Nonzero if priority has been computed already. */ 228 unsigned int priority_known : 1; 229 }; 230 231 extern struct haifa_insn_data *h_i_d; 232 233 /* Accessor macros for h_i_d. There are more in haifa-sched.c and 234 sched-rgn.c. */ 235 #define INSN_DEPEND(INSN) (h_i_d[INSN_UID (INSN)].depend) 236 #define INSN_LUID(INSN) (h_i_d[INSN_UID (INSN)].luid) 237 #define CANT_MOVE(insn) (h_i_d[INSN_UID (insn)].cant_move) 238 #define INSN_DEP_COUNT(INSN) (h_i_d[INSN_UID (INSN)].dep_count) 239 #define INSN_PRIORITY(INSN) (h_i_d[INSN_UID (INSN)].priority) 240 #define INSN_PRIORITY_KNOWN(INSN) (h_i_d[INSN_UID (INSN)].priority_known) 241 #define INSN_COST(INSN) (h_i_d[INSN_UID (INSN)].cost) 242 #define INSN_UNIT(INSN) (h_i_d[INSN_UID (INSN)].units) 243 #define INSN_REG_WEIGHT(INSN) (h_i_d[INSN_UID (INSN)].reg_weight) 244 245 #define INSN_BLOCKAGE(INSN) (h_i_d[INSN_UID (INSN)].blockage) 246 #define UNIT_BITS 5 247 #define BLOCKAGE_MASK ((1 << BLOCKAGE_BITS) - 1) 248 #define ENCODE_BLOCKAGE(U, R) \ 249 (((U) << BLOCKAGE_BITS \ 250 | MIN_BLOCKAGE_COST (R)) << BLOCKAGE_BITS \ 251 | MAX_BLOCKAGE_COST (R)) 252 #define UNIT_BLOCKED(B) ((B) >> (2 * BLOCKAGE_BITS)) 253 #define BLOCKAGE_RANGE(B) \ 254 (((((B) >> BLOCKAGE_BITS) & BLOCKAGE_MASK) << (HOST_BITS_PER_INT / 2)) \ 255 | ((B) & BLOCKAGE_MASK)) 256 257 /* Encodings of the `<name>_unit_blockage_range' function. */ 258 #define MIN_BLOCKAGE_COST(R) ((R) >> (HOST_BITS_PER_INT / 2)) 259 #define MAX_BLOCKAGE_COST(R) ((R) & ((1 << (HOST_BITS_PER_INT / 2)) - 1)) 260 261 extern FILE *sched_dump; 262 extern int sched_verbose; 263 264 #ifndef __GNUC__ 265 #define __inline 266 #endif 267 268 #ifndef HAIFA_INLINE 269 #define HAIFA_INLINE __inline 270 #endif 271 272 /* Functions in sched-vis.c. */ 273 extern void init_target_units PARAMS ((void)); 274 extern void insn_print_units PARAMS ((rtx)); 275 extern void init_block_visualization PARAMS ((void)); 276 extern void print_block_visualization PARAMS ((const char *)); 277 extern void visualize_scheduled_insns PARAMS ((int)); 278 extern void visualize_no_unit PARAMS ((rtx)); 279 extern void visualize_stall_cycles PARAMS ((int)); 280 extern void visualize_alloc PARAMS ((void)); 281 extern void visualize_free PARAMS ((void)); 282 283 /* Functions in sched-deps.c. */ 284 extern void add_dependence PARAMS ((rtx, rtx, enum reg_note)); 285 extern void add_insn_mem_dependence PARAMS ((struct deps *, rtx *, rtx *, rtx, 286 rtx)); 287 extern void sched_analyze PARAMS ((struct deps *, rtx, rtx)); 288 extern void init_deps PARAMS ((struct deps *)); 289 extern void free_deps PARAMS ((struct deps *)); 290 extern void init_deps_global PARAMS ((void)); 291 extern void finish_deps_global PARAMS ((void)); 292 extern void compute_forward_dependences PARAMS ((rtx, rtx)); 293 extern rtx find_insn_list PARAMS ((rtx, rtx)); 294 extern void init_dependency_caches PARAMS ((int)); 295 extern void free_dependency_caches PARAMS ((void)); 296 297 /* Functions in haifa-sched.c. */ 298 extern void get_block_head_tail PARAMS ((int, rtx *, rtx *)); 299 extern int no_real_insns_p PARAMS ((rtx, rtx)); 300 301 extern void rm_line_notes PARAMS ((rtx, rtx)); 302 extern void save_line_notes PARAMS ((int, rtx, rtx)); 303 extern void restore_line_notes PARAMS ((rtx, rtx)); 304 extern void rm_redundant_line_notes PARAMS ((void)); 305 extern void rm_other_notes PARAMS ((rtx, rtx)); 306 307 extern int insn_issue_delay PARAMS ((rtx)); 308 extern int set_priorities PARAMS ((rtx, rtx)); 309 310 extern rtx sched_emit_insn PARAMS ((rtx)); 311 extern void schedule_block PARAMS ((int, int)); 312 extern void sched_init PARAMS ((FILE *)); 313 extern void sched_finish PARAMS ((void)); 314 315 extern void ready_add PARAMS ((struct ready_list *, rtx)); 316 317 /* The following are exported for the benefit of debugging functions. It 318 would be nicer to keep them private to haifa-sched.c. */ 319 extern int insn_unit PARAMS ((rtx)); 320 extern int insn_cost PARAMS ((rtx, rtx, rtx)); 321 extern rtx get_unit_last_insn PARAMS ((int)); 322 extern int actual_hazard_this_instance PARAMS ((int, int, rtx, int, int)); 323 extern void print_insn PARAMS ((char *, rtx, int)); 324