sched-int.h revision 90075 
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
6This file is part of GCC.
7
8GCC is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
10Software Foundation; either version 2, or (at your option) any later
11version.
12
13GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14WARRANTY; without even the implied warranty of MERCHANTABILITY or
15FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
16for more details.
17
18You should have received a copy of the GNU General Public License
19along with GCC; see the file COPYING.  If not, write to the Free
20Software Foundation, 59 Temple Place - Suite 330, Boston, MA
2102111-1307, USA.  */
22
23/* Forward declaration.  */
24struct ready_list;
25
26/* Describe state of dependencies used during sched_analyze phase.  */
27struct 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.  */
113struct 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
160extern struct sched_info *current_sched_info;
161
162/* Indexed by INSN_UID, the collection of all data associated with
163   a single instruction.  */
164
165struct 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
218extern 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
248extern FILE *sched_dump;
249extern 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.  */
260extern void init_target_units PARAMS ((void));
261extern void insn_print_units PARAMS ((rtx));
262extern void init_block_visualization PARAMS ((void));
263extern void print_block_visualization PARAMS ((const char *));
264extern void visualize_scheduled_insns PARAMS ((int));
265extern void visualize_no_unit PARAMS ((rtx));
266extern void visualize_stall_cycles PARAMS ((int));
267extern void visualize_alloc PARAMS ((void));
268extern void visualize_free PARAMS ((void));
269
270/* Functions in sched-deps.c.  */
271extern void add_dependence PARAMS ((rtx, rtx, enum reg_note));
272extern void add_insn_mem_dependence PARAMS ((struct deps *, rtx *, rtx *, rtx,
273					     rtx));
274extern void sched_analyze PARAMS ((struct deps *, rtx, rtx));
275extern void init_deps PARAMS ((struct deps *));
276extern void free_deps PARAMS ((struct deps *));
277extern void init_deps_global PARAMS ((void));
278extern void finish_deps_global PARAMS ((void));
279extern void compute_forward_dependences PARAMS ((rtx, rtx));
280extern rtx find_insn_list PARAMS ((rtx, rtx));
281extern void init_dependency_caches PARAMS ((int));
282extern void free_dependency_caches PARAMS ((void));
283
284/* Functions in haifa-sched.c.  */
285extern void get_block_head_tail PARAMS ((int, rtx *, rtx *));
286extern int no_real_insns_p PARAMS ((rtx, rtx));
287
288extern void rm_line_notes PARAMS ((rtx, rtx));
289extern void save_line_notes PARAMS ((int, rtx, rtx));
290extern void restore_line_notes PARAMS ((rtx, rtx));
291extern void rm_redundant_line_notes PARAMS ((void));
292extern void rm_other_notes PARAMS ((rtx, rtx));
293
294extern int insn_issue_delay PARAMS ((rtx));
295extern int set_priorities PARAMS ((rtx, rtx));
296
297extern void schedule_block PARAMS ((int, int));
298extern void sched_init PARAMS ((FILE *));
299extern void sched_finish PARAMS ((void));
300
301extern 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.  */
305extern int insn_unit PARAMS ((rtx));
306extern int insn_cost PARAMS ((rtx, rtx, rtx));
307extern rtx get_unit_last_insn PARAMS ((int));
308extern int actual_hazard_this_instance PARAMS ((int, int, rtx, int, int));
309
310