321 lines
13 KiB
C
321 lines
13 KiB
C
/* Instruction scheduling pass. This file contains definitions used
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internally in the scheduler.
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Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998,
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1999, 2000, 2001 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 59 Temple Place - Suite 330, Boston, MA
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02111-1307, USA. */
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/* Pointer to data describing the current DFA state. */
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extern state_t curr_state;
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/* Forward declaration. */
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struct ready_list;
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/* Describe state of dependencies used during sched_analyze phase. */
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struct deps
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{
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/* The *_insns and *_mems are paired lists. Each pending memory operation
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will have a pointer to the MEM rtx on one list and a pointer to the
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containing insn on the other list in the same place in the list. */
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/* We can't use add_dependence like the old code did, because a single insn
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may have multiple memory accesses, and hence needs to be on the list
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once for each memory access. Add_dependence won't let you add an insn
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to a list more than once. */
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/* An INSN_LIST containing all insns with pending read operations. */
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rtx pending_read_insns;
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/* An EXPR_LIST containing all MEM rtx's which are pending reads. */
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rtx pending_read_mems;
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/* An INSN_LIST containing all insns with pending write operations. */
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rtx pending_write_insns;
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/* An EXPR_LIST containing all MEM rtx's which are pending writes. */
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rtx pending_write_mems;
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/* Indicates the combined length of the two pending lists. We must prevent
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these lists from ever growing too large since the number of dependencies
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produced is at least O(N*N), and execution time is at least O(4*N*N), as
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a function of the length of these pending lists. */
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int pending_lists_length;
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/* Length of the pending memory flush list. Large functions with no
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calls may build up extremely large lists. */
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int pending_flush_length;
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/* The last insn upon which all memory references must depend.
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This is an insn which flushed the pending lists, creating a dependency
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between it and all previously pending memory references. This creates
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a barrier (or a checkpoint) which no memory reference is allowed to cross.
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This includes all non constant CALL_INSNs. When we do interprocedural
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alias analysis, this restriction can be relaxed.
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This may also be an INSN that writes memory if the pending lists grow
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too large. */
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rtx last_pending_memory_flush;
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/* A list of the last function calls we have seen. We use a list to
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represent last function calls from multiple predecessor blocks.
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Used to prevent register lifetimes from expanding unnecessarily. */
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rtx last_function_call;
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/* A list of insns which use a pseudo register that does not already
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cross a call. We create dependencies between each of those insn
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and the next call insn, to ensure that they won't cross a call after
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scheduling is done. */
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rtx sched_before_next_call;
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/* Used to keep post-call psuedo/hard reg movements together with
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the call. */
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bool in_post_call_group_p;
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/* Set to the tail insn of the outermost libcall block.
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When nonzero, we will mark each insn processed by sched_analyze_insn
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with SCHED_GROUP_P to ensure libcalls are scheduled as a unit. */
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rtx libcall_block_tail_insn;
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/* The maximum register number for the following arrays. Before reload
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this is max_reg_num; after reload it is FIRST_PSEUDO_REGISTER. */
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int max_reg;
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/* Element N is the next insn that sets (hard or pseudo) register
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N within the current basic block; or zero, if there is no
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such insn. Needed for new registers which may be introduced
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by splitting insns. */
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struct deps_reg
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{
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rtx uses;
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rtx sets;
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rtx clobbers;
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int uses_length;
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int clobbers_length;
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} *reg_last;
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/* Element N is set for each register that has any nonzero element
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in reg_last[N].{uses,sets,clobbers}. */
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regset_head reg_last_in_use;
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};
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/* This structure holds some state of the current scheduling pass, and
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contains some function pointers that abstract out some of the non-generic
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functionality from functions such as schedule_block or schedule_insn.
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There is one global variable, current_sched_info, which points to the
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sched_info structure currently in use. */
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struct sched_info
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{
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/* Add all insns that are initially ready to the ready list. Called once
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before scheduling a set of insns. */
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void (*init_ready_list) PARAMS ((struct ready_list *));
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/* Called after taking an insn from the ready list. Returns nonzero if
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this insn can be scheduled, nonzero if we should silently discard it. */
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int (*can_schedule_ready_p) PARAMS ((rtx));
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/* Return nonzero if there are more insns that should be scheduled. */
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int (*schedule_more_p) PARAMS ((void));
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/* Called after an insn has all its dependencies resolved. Return nonzero
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if it should be moved to the ready list or the queue, or zero if we
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should silently discard it. */
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int (*new_ready) PARAMS ((rtx));
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/* Compare priority of two insns. Return a positive number if the second
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insn is to be preferred for scheduling, and a negative one if the first
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is to be preferred. Zero if they are equally good. */
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int (*rank) PARAMS ((rtx, rtx));
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/* Return a string that contains the insn uid and optionally anything else
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necessary to identify this insn in an output. It's valid to use a
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static buffer for this. The ALIGNED parameter should cause the string
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to be formatted so that multiple output lines will line up nicely. */
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const char *(*print_insn) PARAMS ((rtx, int));
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/* Return nonzero if an insn should be included in priority
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calculations. */
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int (*contributes_to_priority) PARAMS ((rtx, rtx));
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/* Called when computing dependencies for a JUMP_INSN. This function
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should store the set of registers that must be considered as set by
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the jump in the regset. */
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void (*compute_jump_reg_dependencies) PARAMS ((rtx, regset));
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/* The boundaries of the set of insns to be scheduled. */
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rtx prev_head, next_tail;
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/* Filled in after the schedule is finished; the first and last scheduled
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insns. */
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rtx head, tail;
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/* If nonzero, enables an additional sanity check in schedule_block. */
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unsigned int queue_must_finish_empty:1;
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/* Nonzero if we should use cselib for better alias analysis. This
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must be 0 if the dependency information is used after sched_analyze
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has completed, e.g. if we're using it to initialize state for successor
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blocks in region scheduling. */
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unsigned int use_cselib:1;
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};
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extern struct sched_info *current_sched_info;
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/* Indexed by INSN_UID, the collection of all data associated with
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a single instruction. */
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struct haifa_insn_data
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{
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/* A list of insns which depend on the instruction. Unlike LOG_LINKS,
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it represents forward dependencies. */
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rtx depend;
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/* The line number note in effect for each insn. For line number
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notes, this indicates whether the note may be reused. */
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rtx line_note;
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/* Logical uid gives the original ordering of the insns. */
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int luid;
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/* A priority for each insn. */
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int priority;
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/* The number of incoming edges in the forward dependency graph.
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As scheduling proceds, counts are decreased. An insn moves to
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the ready queue when its counter reaches zero. */
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int dep_count;
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/* An encoding of the blockage range function. Both unit and range
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are coded. This member is used only for old pipeline interface. */
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unsigned int blockage;
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/* Number of instructions referring to this insn. */
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int ref_count;
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/* The minimum clock tick at which the insn becomes ready. This is
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used to note timing constraints for the insns in the pending list. */
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int tick;
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short cost;
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/* An encoding of the function units used. This member is used only
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for old pipeline interface. */
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short units;
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/* This weight is an estimation of the insn's contribution to
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register pressure. */
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short reg_weight;
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/* Some insns (e.g. call) are not allowed to move across blocks. */
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unsigned int cant_move : 1;
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/* Set if there's DEF-USE dependence between some speculatively
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moved load insn and this one. */
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unsigned int fed_by_spec_load : 1;
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unsigned int is_load_insn : 1;
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/* Nonzero if priority has been computed already. */
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unsigned int priority_known : 1;
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};
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extern struct haifa_insn_data *h_i_d;
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/* Accessor macros for h_i_d. There are more in haifa-sched.c and
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sched-rgn.c. */
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#define INSN_DEPEND(INSN) (h_i_d[INSN_UID (INSN)].depend)
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#define INSN_LUID(INSN) (h_i_d[INSN_UID (INSN)].luid)
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#define CANT_MOVE(insn) (h_i_d[INSN_UID (insn)].cant_move)
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#define INSN_DEP_COUNT(INSN) (h_i_d[INSN_UID (INSN)].dep_count)
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#define INSN_PRIORITY(INSN) (h_i_d[INSN_UID (INSN)].priority)
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#define INSN_PRIORITY_KNOWN(INSN) (h_i_d[INSN_UID (INSN)].priority_known)
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#define INSN_COST(INSN) (h_i_d[INSN_UID (INSN)].cost)
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#define INSN_UNIT(INSN) (h_i_d[INSN_UID (INSN)].units)
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#define INSN_REG_WEIGHT(INSN) (h_i_d[INSN_UID (INSN)].reg_weight)
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#define INSN_BLOCKAGE(INSN) (h_i_d[INSN_UID (INSN)].blockage)
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#define UNIT_BITS 5
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#define BLOCKAGE_MASK ((1 << BLOCKAGE_BITS) - 1)
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#define ENCODE_BLOCKAGE(U, R) \
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(((U) << BLOCKAGE_BITS \
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| MIN_BLOCKAGE_COST (R)) << BLOCKAGE_BITS \
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| MAX_BLOCKAGE_COST (R))
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#define UNIT_BLOCKED(B) ((B) >> (2 * BLOCKAGE_BITS))
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#define BLOCKAGE_RANGE(B) \
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(((((B) >> BLOCKAGE_BITS) & BLOCKAGE_MASK) << (HOST_BITS_PER_INT / 2)) \
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| ((B) & BLOCKAGE_MASK))
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/* Encodings of the `<name>_unit_blockage_range' function. */
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#define MIN_BLOCKAGE_COST(R) ((R) >> (HOST_BITS_PER_INT / 2))
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#define MAX_BLOCKAGE_COST(R) ((R) & ((1 << (HOST_BITS_PER_INT / 2)) - 1))
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extern FILE *sched_dump;
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extern int sched_verbose;
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#ifndef __GNUC__
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#define __inline
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#endif
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#ifndef HAIFA_INLINE
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#define HAIFA_INLINE __inline
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#endif
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/* Functions in sched-vis.c. */
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extern void init_target_units PARAMS ((void));
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extern void insn_print_units PARAMS ((rtx));
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extern void init_block_visualization PARAMS ((void));
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extern void print_block_visualization PARAMS ((const char *));
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extern void visualize_scheduled_insns PARAMS ((int));
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extern void visualize_no_unit PARAMS ((rtx));
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extern void visualize_stall_cycles PARAMS ((int));
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extern void visualize_alloc PARAMS ((void));
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extern void visualize_free PARAMS ((void));
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/* Functions in sched-deps.c. */
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extern void add_dependence PARAMS ((rtx, rtx, enum reg_note));
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extern void add_insn_mem_dependence PARAMS ((struct deps *, rtx *, rtx *, rtx,
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rtx));
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extern void sched_analyze PARAMS ((struct deps *, rtx, rtx));
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extern void init_deps PARAMS ((struct deps *));
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extern void free_deps PARAMS ((struct deps *));
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extern void init_deps_global PARAMS ((void));
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extern void finish_deps_global PARAMS ((void));
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extern void compute_forward_dependences PARAMS ((rtx, rtx));
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extern rtx find_insn_list PARAMS ((rtx, rtx));
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extern void init_dependency_caches PARAMS ((int));
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extern void free_dependency_caches PARAMS ((void));
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/* Functions in haifa-sched.c. */
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extern void get_block_head_tail PARAMS ((int, rtx *, rtx *));
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extern int no_real_insns_p PARAMS ((rtx, rtx));
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extern void rm_line_notes PARAMS ((rtx, rtx));
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extern void save_line_notes PARAMS ((int, rtx, rtx));
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extern void restore_line_notes PARAMS ((rtx, rtx));
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extern void rm_redundant_line_notes PARAMS ((void));
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extern void rm_other_notes PARAMS ((rtx, rtx));
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extern int insn_issue_delay PARAMS ((rtx));
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extern int set_priorities PARAMS ((rtx, rtx));
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extern rtx sched_emit_insn PARAMS ((rtx));
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extern void schedule_block PARAMS ((int, int));
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extern void sched_init PARAMS ((FILE *));
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extern void sched_finish PARAMS ((void));
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extern void ready_add PARAMS ((struct ready_list *, rtx));
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/* The following are exported for the benefit of debugging functions. It
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would be nicer to keep them private to haifa-sched.c. */
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extern int insn_unit PARAMS ((rtx));
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extern int insn_cost PARAMS ((rtx, rtx, rtx));
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extern rtx get_unit_last_insn PARAMS ((int));
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extern int actual_hazard_this_instance PARAMS ((int, int, rtx, int, int));
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extern void print_insn PARAMS ((char *, rtx, int));
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