sched-int.h revision 102780 
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  /* Set to the tail insn of the outermost libcall block.
87
88     When nonzero, we will mark each insn processed by sched_analyze_insn
89     with SCHED_GROUP_P to ensure libcalls are scheduled as a unit.  */
90  rtx libcall_block_tail_insn;
91
92  /* The maximum register number for the following arrays.  Before reload
93     this is max_reg_num; after reload it is FIRST_PSEUDO_REGISTER.  */
94  int max_reg;
95
96  /* Element N is the next insn that sets (hard or pseudo) register
97     N within the current basic block; or zero, if there is no
98     such insn.  Needed for new registers which may be introduced
99     by splitting insns.  */
100  struct deps_reg
101    {
102      rtx uses;
103      rtx sets;
104      rtx clobbers;
105      int uses_length;
106      int clobbers_length;
107    } *reg_last;
108
109  /* Element N is set for each register that has any non-zero element
110     in reg_last[N].{uses,sets,clobbers}.  */
111  regset_head reg_last_in_use;
112};
113
114/* This structure holds some state of the current scheduling pass, and
115   contains some function pointers that abstract out some of the non-generic
116   functionality from functions such as schedule_block or schedule_insn.
117   There is one global variable, current_sched_info, which points to the
118   sched_info structure currently in use.  */
119struct sched_info
120{
121  /* Add all insns that are initially ready to the ready list.  Called once
122     before scheduling a set of insns.  */
123  void (*init_ready_list) PARAMS ((struct ready_list *));
124  /* Called after taking an insn from the ready list.  Returns nonzero if
125     this insn can be scheduled, nonzero if we should silently discard it.  */
126  int (*can_schedule_ready_p) PARAMS ((rtx));
127  /* Return nonzero if there are more insns that should be scheduled.  */
128  int (*schedule_more_p) PARAMS ((void));
129  /* Called after an insn has all its dependencies resolved.  Return nonzero
130     if it should be moved to the ready list or the queue, or zero if we
131     should silently discard it.  */
132  int (*new_ready) PARAMS ((rtx));
133  /* Compare priority of two insns.  Return a positive number if the second
134     insn is to be preferred for scheduling, and a negative one if the first
135     is to be preferred.  Zero if they are equally good.  */
136  int (*rank) PARAMS ((rtx, rtx));
137  /* Return a string that contains the insn uid and optionally anything else
138     necessary to identify this insn in an output.  It's valid to use a
139     static buffer for this.  The ALIGNED parameter should cause the string
140     to be formatted so that multiple output lines will line up nicely.  */
141  const char *(*print_insn) PARAMS ((rtx, int));
142  /* Return nonzero if an insn should be included in priority
143     calculations.  */
144  int (*contributes_to_priority) PARAMS ((rtx, rtx));
145  /* Called when computing dependencies for a JUMP_INSN.  This function
146     should store the set of registers that must be considered as set by
147     the jump in the regset.  */
148  void (*compute_jump_reg_dependencies) PARAMS ((rtx, regset));
149
150  /* The boundaries of the set of insns to be scheduled.  */
151  rtx prev_head, next_tail;
152
153  /* Filled in after the schedule is finished; the first and last scheduled
154     insns.  */
155  rtx head, tail;
156
157  /* If nonzero, enables an additional sanity check in schedule_block.  */
158  unsigned int queue_must_finish_empty:1;
159  /* Nonzero if we should use cselib for better alias analysis.  This
160     must be 0 if the dependency information is used after sched_analyze
161     has completed, e.g. if we're using it to initialize state for successor
162     blocks in region scheduling.  */
163  unsigned int use_cselib:1;
164};
165
166extern struct sched_info *current_sched_info;
167
168/* Indexed by INSN_UID, the collection of all data associated with
169   a single instruction.  */
170
171struct haifa_insn_data
172{
173  /* A list of insns which depend on the instruction.  Unlike LOG_LINKS,
174     it represents forward dependencies.  */
175  rtx depend;
176
177  /* The line number note in effect for each insn.  For line number
178     notes, this indicates whether the note may be reused.  */
179  rtx line_note;
180
181  /* Logical uid gives the original ordering of the insns.  */
182  int luid;
183
184  /* A priority for each insn.  */
185  int priority;
186
187  /* The number of incoming edges in the forward dependency graph.
188     As scheduling proceds, counts are decreased.  An insn moves to
189     the ready queue when its counter reaches zero.  */
190  int dep_count;
191
192  /* An encoding of the blockage range function.  Both unit and range
193     are coded.  */
194  unsigned int blockage;
195
196  /* Number of instructions referring to this insn.  */
197  int ref_count;
198
199  /* The minimum clock tick at which the insn becomes ready.  This is
200     used to note timing constraints for the insns in the pending list.  */
201  int tick;
202
203  short cost;
204
205  /* An encoding of the function units used.  */
206  short units;
207
208  /* This weight is an estimation of the insn's contribution to
209     register pressure.  */
210  short reg_weight;
211
212  /* Some insns (e.g. call) are not allowed to move across blocks.  */
213  unsigned int cant_move : 1;
214
215  /* Set if there's DEF-USE dependence between some speculatively
216     moved load insn and this one.  */
217  unsigned int fed_by_spec_load : 1;
218  unsigned int is_load_insn : 1;
219
220  /* Nonzero if priority has been computed already.  */
221  unsigned int priority_known : 1;
222};
223
224extern struct haifa_insn_data *h_i_d;
225
226/* Accessor macros for h_i_d.  There are more in haifa-sched.c and
227   sched-rgn.c.  */
228#define INSN_DEPEND(INSN)	(h_i_d[INSN_UID (INSN)].depend)
229#define INSN_LUID(INSN)		(h_i_d[INSN_UID (INSN)].luid)
230#define CANT_MOVE(insn)		(h_i_d[INSN_UID (insn)].cant_move)
231#define INSN_DEP_COUNT(INSN)	(h_i_d[INSN_UID (INSN)].dep_count)
232#define INSN_PRIORITY(INSN)	(h_i_d[INSN_UID (INSN)].priority)
233#define INSN_PRIORITY_KNOWN(INSN) (h_i_d[INSN_UID (INSN)].priority_known)
234#define INSN_COST(INSN)		(h_i_d[INSN_UID (INSN)].cost)
235#define INSN_UNIT(INSN)		(h_i_d[INSN_UID (INSN)].units)
236#define INSN_REG_WEIGHT(INSN)	(h_i_d[INSN_UID (INSN)].reg_weight)
237
238#define INSN_BLOCKAGE(INSN)	(h_i_d[INSN_UID (INSN)].blockage)
239#define UNIT_BITS		5
240#define BLOCKAGE_MASK		((1 << BLOCKAGE_BITS) - 1)
241#define ENCODE_BLOCKAGE(U, R)			\
242  (((U) << BLOCKAGE_BITS			\
243    | MIN_BLOCKAGE_COST (R)) << BLOCKAGE_BITS	\
244   | MAX_BLOCKAGE_COST (R))
245#define UNIT_BLOCKED(B)		((B) >> (2 * BLOCKAGE_BITS))
246#define BLOCKAGE_RANGE(B)                                                \
247  (((((B) >> BLOCKAGE_BITS) & BLOCKAGE_MASK) << (HOST_BITS_PER_INT / 2)) \
248   | ((B) & BLOCKAGE_MASK))
249
250/* Encodings of the `<name>_unit_blockage_range' function.  */
251#define MIN_BLOCKAGE_COST(R) ((R) >> (HOST_BITS_PER_INT / 2))
252#define MAX_BLOCKAGE_COST(R) ((R) & ((1 << (HOST_BITS_PER_INT / 2)) - 1))
253
254extern FILE *sched_dump;
255extern int sched_verbose;
256
257#ifndef __GNUC__
258#define __inline
259#endif
260
261#ifndef HAIFA_INLINE
262#define HAIFA_INLINE __inline
263#endif
264
265/* Functions in sched-vis.c.  */
266extern void init_target_units PARAMS ((void));
267extern void insn_print_units PARAMS ((rtx));
268extern void init_block_visualization PARAMS ((void));
269extern void print_block_visualization PARAMS ((const char *));
270extern void visualize_scheduled_insns PARAMS ((int));
271extern void visualize_no_unit PARAMS ((rtx));
272extern void visualize_stall_cycles PARAMS ((int));
273extern void visualize_alloc PARAMS ((void));
274extern void visualize_free PARAMS ((void));
275
276/* Functions in sched-deps.c.  */
277extern void add_dependence PARAMS ((rtx, rtx, enum reg_note));
278extern void add_insn_mem_dependence PARAMS ((struct deps *, rtx *, rtx *, rtx,
279					     rtx));
280extern void sched_analyze PARAMS ((struct deps *, rtx, rtx));
281extern void init_deps PARAMS ((struct deps *));
282extern void free_deps PARAMS ((struct deps *));
283extern void init_deps_global PARAMS ((void));
284extern void finish_deps_global PARAMS ((void));
285extern void compute_forward_dependences PARAMS ((rtx, rtx));
286extern rtx find_insn_list PARAMS ((rtx, rtx));
287extern void init_dependency_caches PARAMS ((int));
288extern void free_dependency_caches PARAMS ((void));
289
290/* Functions in haifa-sched.c.  */
291extern void get_block_head_tail PARAMS ((int, rtx *, rtx *));
292extern int no_real_insns_p PARAMS ((rtx, rtx));
293
294extern void rm_line_notes PARAMS ((rtx, rtx));
295extern void save_line_notes PARAMS ((int, rtx, rtx));
296extern void restore_line_notes PARAMS ((rtx, rtx));
297extern void rm_redundant_line_notes PARAMS ((void));
298extern void rm_other_notes PARAMS ((rtx, rtx));
299
300extern int insn_issue_delay PARAMS ((rtx));
301extern int set_priorities PARAMS ((rtx, rtx));
302
303extern rtx sched_emit_insn PARAMS ((rtx));
304extern void schedule_block PARAMS ((int, int));
305extern void sched_init PARAMS ((FILE *));
306extern void sched_finish PARAMS ((void));
307
308extern void ready_add PARAMS ((struct ready_list *, rtx));
309
310/* The following are exported for the benefit of debugging functions.  It
311   would be nicer to keep them private to haifa-sched.c.  */
312extern int insn_unit PARAMS ((rtx));
313extern int insn_cost PARAMS ((rtx, rtx, rtx));
314extern rtx get_unit_last_insn PARAMS ((int));
315extern int actual_hazard_this_instance PARAMS ((int, int, rtx, int, int));
316
317