sched-int.h revision 117395 
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/* Pointer to data describing the current DFA state.  */
24extern state_t curr_state;
25
26/* Forward declaration.  */
27struct ready_list;
28
29/* Describe state of dependencies used during sched_analyze phase.  */
30struct 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
117/* This structure holds some state of the current scheduling pass, and
118   contains some function pointers that abstract out some of the non-generic
119   functionality from functions such as schedule_block or schedule_insn.
120   There is one global variable, current_sched_info, which points to the
121   sched_info structure currently in use.  */
122struct sched_info
123{
124  /* Add all insns that are initially ready to the ready list.  Called once
125     before scheduling a set of insns.  */
126  void (*init_ready_list) PARAMS ((struct ready_list *));
127  /* Called after taking an insn from the ready list.  Returns nonzero if
128     this insn can be scheduled, nonzero if we should silently discard it.  */
129  int (*can_schedule_ready_p) PARAMS ((rtx));
130  /* Return nonzero if there are more insns that should be scheduled.  */
131  int (*schedule_more_p) PARAMS ((void));
132  /* Called after an insn has all its dependencies resolved.  Return nonzero
133     if it should be moved to the ready list or the queue, or zero if we
134     should silently discard it.  */
135  int (*new_ready) PARAMS ((rtx));
136  /* Compare priority of two insns.  Return a positive number if the second
137     insn is to be preferred for scheduling, and a negative one if the first
138     is to be preferred.  Zero if they are equally good.  */
139  int (*rank) PARAMS ((rtx, rtx));
140  /* Return a string that contains the insn uid and optionally anything else
141     necessary to identify this insn in an output.  It's valid to use a
142     static buffer for this.  The ALIGNED parameter should cause the string
143     to be formatted so that multiple output lines will line up nicely.  */
144  const char *(*print_insn) PARAMS ((rtx, int));
145  /* Return nonzero if an insn should be included in priority
146     calculations.  */
147  int (*contributes_to_priority) PARAMS ((rtx, rtx));
148  /* Called when computing dependencies for a JUMP_INSN.  This function
149     should store the set of registers that must be considered as set by
150     the jump in the regset.  */
151  void (*compute_jump_reg_dependencies) PARAMS ((rtx, regset));
152
153  /* The boundaries of the set of insns to be scheduled.  */
154  rtx prev_head, next_tail;
155
156  /* Filled in after the schedule is finished; the first and last scheduled
157     insns.  */
158  rtx head, tail;
159
160  /* If nonzero, enables an additional sanity check in schedule_block.  */
161  unsigned int queue_must_finish_empty:1;
162  /* Nonzero if we should use cselib for better alias analysis.  This
163     must be 0 if the dependency information is used after sched_analyze
164     has completed, e.g. if we're using it to initialize state for successor
165     blocks in region scheduling.  */
166  unsigned int use_cselib:1;
167};
168
169extern struct sched_info *current_sched_info;
170
171/* Indexed by INSN_UID, the collection of all data associated with
172   a single instruction.  */
173
174struct haifa_insn_data
175{
176  /* A list of insns which depend on the instruction.  Unlike LOG_LINKS,
177     it represents forward dependencies.  */
178  rtx depend;
179
180  /* The line number note in effect for each insn.  For line number
181     notes, this indicates whether the note may be reused.  */
182  rtx line_note;
183
184  /* Logical uid gives the original ordering of the insns.  */
185  int luid;
186
187  /* A priority for each insn.  */
188  int priority;
189
190  /* The number of incoming edges in the forward dependency graph.
191     As scheduling proceds, counts are decreased.  An insn moves to
192     the ready queue when its counter reaches zero.  */
193  int dep_count;
194
195  /* An encoding of the blockage range function.  Both unit and range
196     are coded.  This member is used only for old pipeline interface.  */
197  unsigned int blockage;
198
199  /* Number of instructions referring to this insn.  */
200  int ref_count;
201
202  /* The minimum clock tick at which the insn becomes ready.  This is
203     used to note timing constraints for the insns in the pending list.  */
204  int tick;
205
206  short cost;
207
208  /* An encoding of the function units used.  This member is used only
209     for old pipeline interface.  */
210  short units;
211
212  /* This weight is an estimation of the insn's contribution to
213     register pressure.  */
214  short reg_weight;
215
216  /* Some insns (e.g. call) are not allowed to move across blocks.  */
217  unsigned int cant_move : 1;
218
219  /* Set if there's DEF-USE dependence between some speculatively
220     moved load insn and this one.  */
221  unsigned int fed_by_spec_load : 1;
222  unsigned int is_load_insn : 1;
223
224  /* Nonzero if priority has been computed already.  */
225  unsigned int priority_known : 1;
226};
227
228extern struct haifa_insn_data *h_i_d;
229
230/* Accessor macros for h_i_d.  There are more in haifa-sched.c and
231   sched-rgn.c.  */
232#define INSN_DEPEND(INSN)	(h_i_d[INSN_UID (INSN)].depend)
233#define INSN_LUID(INSN)		(h_i_d[INSN_UID (INSN)].luid)
234#define CANT_MOVE(insn)		(h_i_d[INSN_UID (insn)].cant_move)
235#define INSN_DEP_COUNT(INSN)	(h_i_d[INSN_UID (INSN)].dep_count)
236#define INSN_PRIORITY(INSN)	(h_i_d[INSN_UID (INSN)].priority)
237#define INSN_PRIORITY_KNOWN(INSN) (h_i_d[INSN_UID (INSN)].priority_known)
238#define INSN_COST(INSN)		(h_i_d[INSN_UID (INSN)].cost)
239#define INSN_UNIT(INSN)		(h_i_d[INSN_UID (INSN)].units)
240#define INSN_REG_WEIGHT(INSN)	(h_i_d[INSN_UID (INSN)].reg_weight)
241
242#define INSN_BLOCKAGE(INSN)	(h_i_d[INSN_UID (INSN)].blockage)
243#define UNIT_BITS		5
244#define BLOCKAGE_MASK		((1 << BLOCKAGE_BITS) - 1)
245#define ENCODE_BLOCKAGE(U, R)			\
246  (((U) << BLOCKAGE_BITS			\
247    | MIN_BLOCKAGE_COST (R)) << BLOCKAGE_BITS	\
248   | MAX_BLOCKAGE_COST (R))
249#define UNIT_BLOCKED(B)		((B) >> (2 * BLOCKAGE_BITS))
250#define BLOCKAGE_RANGE(B)                                                \
251  (((((B) >> BLOCKAGE_BITS) & BLOCKAGE_MASK) << (HOST_BITS_PER_INT / 2)) \
252   | ((B) & BLOCKAGE_MASK))
253
254/* Encodings of the `<name>_unit_blockage_range' function.  */
255#define MIN_BLOCKAGE_COST(R) ((R) >> (HOST_BITS_PER_INT / 2))
256#define MAX_BLOCKAGE_COST(R) ((R) & ((1 << (HOST_BITS_PER_INT / 2)) - 1))
257
258extern FILE *sched_dump;
259extern int sched_verbose;
260
261#ifndef __GNUC__
262#define __inline
263#endif
264
265#ifndef HAIFA_INLINE
266#define HAIFA_INLINE __inline
267#endif
268
269/* Functions in sched-vis.c.  */
270extern void init_target_units PARAMS ((void));
271extern void insn_print_units PARAMS ((rtx));
272extern void init_block_visualization PARAMS ((void));
273extern void print_block_visualization PARAMS ((const char *));
274extern void visualize_scheduled_insns PARAMS ((int));
275extern void visualize_no_unit PARAMS ((rtx));
276extern void visualize_stall_cycles PARAMS ((int));
277extern void visualize_alloc PARAMS ((void));
278extern void visualize_free PARAMS ((void));
279
280/* Functions in sched-deps.c.  */
281extern void add_dependence PARAMS ((rtx, rtx, enum reg_note));
282extern void add_insn_mem_dependence PARAMS ((struct deps *, rtx *, rtx *, rtx,
283					     rtx));
284extern void sched_analyze PARAMS ((struct deps *, rtx, rtx));
285extern void init_deps PARAMS ((struct deps *));
286extern void free_deps PARAMS ((struct deps *));
287extern void init_deps_global PARAMS ((void));
288extern void finish_deps_global PARAMS ((void));
289extern void compute_forward_dependences PARAMS ((rtx, rtx));
290extern rtx find_insn_list PARAMS ((rtx, rtx));
291extern void init_dependency_caches PARAMS ((int));
292extern void free_dependency_caches PARAMS ((void));
293
294/* Functions in haifa-sched.c.  */
295extern void get_block_head_tail PARAMS ((int, rtx *, rtx *));
296extern int no_real_insns_p PARAMS ((rtx, rtx));
297
298extern void rm_line_notes PARAMS ((rtx, rtx));
299extern void save_line_notes PARAMS ((int, rtx, rtx));
300extern void restore_line_notes PARAMS ((rtx, rtx));
301extern void rm_redundant_line_notes PARAMS ((void));
302extern void rm_other_notes PARAMS ((rtx, rtx));
303
304extern int insn_issue_delay PARAMS ((rtx));
305extern int set_priorities PARAMS ((rtx, rtx));
306
307extern rtx sched_emit_insn PARAMS ((rtx));
308extern void schedule_block PARAMS ((int, int));
309extern void sched_init PARAMS ((FILE *));
310extern void sched_finish PARAMS ((void));
311
312extern void ready_add PARAMS ((struct ready_list *, rtx));
313
314/* The following are exported for the benefit of debugging functions.  It
315   would be nicer to keep them private to haifa-sched.c.  */
316extern int insn_unit PARAMS ((rtx));
317extern int insn_cost PARAMS ((rtx, rtx, rtx));
318extern rtx get_unit_last_insn PARAMS ((int));
319extern int actual_hazard_this_instance PARAMS ((int, int, rtx, int, int));
320extern void print_insn PARAMS ((char *, rtx, int));
321