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 Free Software Foundation, Inc.
6 This file is part of GNU CC.
8 GNU CC is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by the
10 Free Software Foundation; either version 2, or (at your option) any
13 GNU CC is distributed in the hope that it will be useful, but WITHOUT
14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GNU CC; see the file COPYING. If not, write to the Free
20 the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
23 /* Forward declaration. */
26 /* Describe state of dependencies used during sched_analyze phase. */
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. */
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. */
38 /* An INSN_LIST containing all insns with pending read operations. */
39 rtx pending_read_insns;
41 /* An EXPR_LIST containing all MEM rtx's which are pending reads. */
42 rtx pending_read_mems;
44 /* An INSN_LIST containing all insns with pending write operations. */
45 rtx pending_write_insns;
47 /* An EXPR_LIST containing all MEM rtx's which are pending writes. */
48 rtx pending_write_mems;
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;
56 /* The last insn upon which all memory references must depend.
57 This is an insn which flushed the pending lists, creating a dependency
58 between it and all previously pending memory references. This creates
59 a barrier (or a checkpoint) which no memory reference is allowed to cross.
61 This includes all non constant CALL_INSNs. When we do interprocedural
62 alias analysis, this restriction can be relaxed.
63 This may also be an INSN that writes memory if the pending lists grow
65 rtx last_pending_memory_flush;
67 /* The last function call we have seen. All hard regs, and, of course,
68 the last function call, must depend on this. */
69 rtx last_function_call;
71 /* Used to keep post-call psuedo/hard reg movements together with
73 int in_post_call_group_p;
75 /* The LOG_LINKS field of this is a list of insns which use a pseudo
76 register that does not already cross a call. We create
77 dependencies between each of those insn and the next call insn,
78 to ensure that they won't cross a call after scheduling is done. */
79 rtx sched_before_next_call;
81 /* Element N is the next insn that sets (hard or pseudo) register
82 N within the current basic block; or zero, if there is no
83 such insn. Needed for new registers which may be introduced
84 by splitting insns. */
87 rtx *reg_last_clobbers;
90 /* This structure holds some state of the current scheduling pass, and
91 contains some function pointers that abstract out some of the non-generic
92 functionality from functions such as schedule_block or schedule_insn.
93 There is one global variable, current_sched_info, which points to the
94 sched_info structure currently in use. */
97 /* Add all insns that are initially ready to the ready list. Called once
98 before scheduling a set of insns. */
99 void (*init_ready_list) PARAMS ((struct ready_list *));
100 /* Called after taking an insn from the ready list. Returns nonzero if
101 this insn can be scheduled, nonzero if we should silently discard it. */
102 int (*can_schedule_ready_p) PARAMS ((rtx));
103 /* Return nonzero if there are more insns that should be scheduled. */
104 int (*schedule_more_p) PARAMS ((void));
105 /* Called after an insn has all its dependencies resolved. Return nonzero
106 if it should be moved to the ready list or the queue, or zero if we
107 should silently discard it. */
108 int (*new_ready) PARAMS ((rtx));
109 /* Compare priority of two insns. Return a positive number if the second
110 insn is to be preferred for scheduling, and a negative one if the first
111 is to be preferred. Zero if they are equally good. */
112 int (*rank) PARAMS ((rtx, rtx));
113 /* Return a string that contains the insn uid and optionally anything else
114 necessary to identify this insn in an output. It's valid to use a
115 static buffer for this. The ALIGNED parameter should cause the string
116 to be formatted so that multiple output lines will line up nicely. */
117 const char *(*print_insn) PARAMS ((rtx, int));
119 /* The boundaries of the set of insns to be scheduled. */
120 rtx prev_head, next_tail;
122 /* Filled in after the schedule is finished; the first and last scheduled
126 /* If nonzero, enables an additional sanity check in schedule_block. */
127 int queue_must_finish_empty;
130 extern struct sched_info *current_sched_info;
132 /* Indexed by INSN_UID, the collection of all data associated with
133 a single instruction. */
135 struct haifa_insn_data
137 /* A list of insns which depend on the instruction. Unlike LOG_LINKS,
138 it represents forward dependancies. */
141 /* The line number note in effect for each insn. For line number
142 notes, this indicates whether the note may be reused. */
145 /* Logical uid gives the original ordering of the insns. */
148 /* A priority for each insn. */
151 /* The number of incoming edges in the forward dependency graph.
152 As scheduling proceds, counts are decreased. An insn moves to
153 the ready queue when its counter reaches zero. */
156 /* An encoding of the blockage range function. Both unit and range
158 unsigned int blockage;
160 /* Number of instructions referring to this insn. */
163 /* The minimum clock tick at which the insn becomes ready. This is
164 used to note timing constraints for the insns in the pending list. */
169 /* An encoding of the function units used. */
172 /* This weight is an estimation of the insn's contribution to
173 register pressure. */
176 /* Some insns (e.g. call) are not allowed to move across blocks. */
177 unsigned int cant_move : 1;
179 /* Set if there's DEF-USE dependance between some speculatively
180 moved load insn and this one. */
181 unsigned int fed_by_spec_load : 1;
182 unsigned int is_load_insn : 1;
185 extern struct haifa_insn_data *h_i_d;
187 /* Accessor macros for h_i_d. There are more in haifa-sched.c. */
188 #define INSN_DEPEND(INSN) (h_i_d[INSN_UID (INSN)].depend)
189 #define INSN_LUID(INSN) (h_i_d[INSN_UID (INSN)].luid)
190 #define CANT_MOVE(insn) (h_i_d[INSN_UID (insn)].cant_move)
191 #define INSN_DEP_COUNT(INSN) (h_i_d[INSN_UID (INSN)].dep_count)
193 extern FILE *sched_dump;
200 #define HAIFA_INLINE __inline
203 /* Functions in sched-vis.c. */
204 extern void init_target_units PARAMS ((void));
205 extern void insn_print_units PARAMS ((rtx));
206 extern void init_block_visualization PARAMS ((void));
207 extern void print_block_visualization PARAMS ((const char *));
208 extern void visualize_scheduled_insns PARAMS ((int));
209 extern void visualize_no_unit PARAMS ((rtx));
210 extern void visualize_stall_cycles PARAMS ((int));
211 extern void visualize_alloc PARAMS ((void));
212 extern void visualize_free PARAMS ((void));
214 /* Functions in sched-deps.c. */
215 extern void add_dependence PARAMS ((rtx, rtx, enum reg_note));
216 extern void add_insn_mem_dependence PARAMS ((struct deps *, rtx *, rtx *, rtx,
218 extern void sched_analyze PARAMS ((struct deps *, rtx, rtx));
219 extern void init_deps PARAMS ((struct deps *));
220 extern void free_deps PARAMS ((struct deps *));
221 extern void init_deps_global PARAMS ((void));
222 extern void finish_deps_global PARAMS ((void));
223 extern void compute_forward_dependences PARAMS ((rtx, rtx));
224 extern int find_insn_mem_list PARAMS ((rtx, rtx, rtx, rtx));
225 extern rtx find_insn_list PARAMS ((rtx, rtx));
226 extern void init_dependency_caches PARAMS ((int));
227 extern void free_dependency_caches PARAMS ((void));
229 /* Functions in haifa-sched.c. */
230 extern int insn_unit PARAMS ((rtx));
231 extern rtx get_unit_last_insn PARAMS ((int));
232 extern int actual_hazard_this_instance PARAMS ((int, int, rtx, int, int));