332 lines
9.7 KiB
C
332 lines
9.7 KiB
C
/* Routines for liveness in SSA trees.
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Copyright (C) 2003-2020 Free Software Foundation, Inc.
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Contributed by Andrew MacLeod <amacleod@redhat.com>
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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
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License 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 COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#ifndef _TREE_SSA_LIVE_H
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#define _TREE_SSA_LIVE_H 1
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#include "partition.h"
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/* Used to create the variable mapping when we go out of SSA form.
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Mapping from an ssa_name to a partition number is maintained, as well as
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partition number back to ssa_name.
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This data structure also supports "views", which work on a subset of all
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partitions. This allows the coalescer to decide what partitions are
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interesting to it, and only work with those partitions. Whenever the view
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is changed, the partition numbers change, but none of the partition groupings
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change. (ie, it is truly a view since it doesn't change anything)
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The final component of the data structure is the basevar map. This provides
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a list of all the different base variables which occur in a partition view,
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and a unique index for each one. Routines are provided to quickly produce
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the base variable of a partition.
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Note that members of a partition MUST all have the same base variable. */
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typedef struct _var_map
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{
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/* The partition manager of all variables. */
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partition var_partition;
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/* Vector for managing partitions views. */
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int *partition_to_view;
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int *view_to_partition;
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/* Current number of partitions in var_map based on the current view. */
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unsigned int num_partitions;
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/* Original full partition size. */
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unsigned int partition_size;
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/* Number of base variables in the base var list. */
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int num_basevars;
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/* Map of partitions numbers to base variable table indexes. */
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int *partition_to_base_index;
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/* Bitmap of basic block. It describes the region within which the analysis
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is done. Using pointer avoids allocating memory in out-of-ssa case. */
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bitmap bmp_bbs;
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/* Vector of basic block in the region. */
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vec<basic_block> vec_bbs;
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/* True if this map is for out-of-ssa, otherwise for live range
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computation. When for out-of-ssa, it also means the var map is computed
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for whole current function. */
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bool outofssa_p;
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} *var_map;
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/* Value used to represent no partition number. */
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#define NO_PARTITION -1
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extern var_map init_var_map (int, class loop* = NULL);
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extern void delete_var_map (var_map);
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extern int var_union (var_map, tree, tree);
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extern void partition_view_normal (var_map);
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extern void partition_view_bitmap (var_map, bitmap);
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extern void dump_scope_blocks (FILE *, dump_flags_t);
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extern void debug_scope_block (tree, dump_flags_t);
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extern void debug_scope_blocks (dump_flags_t);
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extern void remove_unused_locals (void);
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extern void dump_var_map (FILE *, var_map);
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extern void debug (_var_map &ref);
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extern void debug (_var_map *ptr);
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/* Return TRUE if region of the MAP contains basic block BB. */
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inline bool
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region_contains_p (var_map map, basic_block bb)
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{
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/* It's possible that the function is called with ENTRY_BLOCK/EXIT_BLOCK. */
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if (map->outofssa_p)
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return (bb->index != ENTRY_BLOCK && bb->index != EXIT_BLOCK);
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return bitmap_bit_p (map->bmp_bbs, bb->index);
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}
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/* Return number of partitions in MAP. */
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static inline unsigned
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num_var_partitions (var_map map)
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{
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return map->num_partitions;
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}
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/* Given partition index I from MAP, return the variable which represents that
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partition. */
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static inline tree
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partition_to_var (var_map map, int i)
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{
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tree name;
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if (map->view_to_partition)
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i = map->view_to_partition[i];
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i = partition_find (map->var_partition, i);
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name = ssa_name (i);
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return name;
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}
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/* Given ssa_name VERSION, if it has a partition in MAP, return the var it
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is associated with. Otherwise return NULL. */
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static inline tree
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version_to_var (var_map map, int version)
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{
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int part;
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part = partition_find (map->var_partition, version);
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if (map->partition_to_view)
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part = map->partition_to_view[part];
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if (part == NO_PARTITION)
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return NULL_TREE;
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return partition_to_var (map, part);
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}
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/* Given VAR, return the partition number in MAP which contains it.
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NO_PARTITION is returned if it's not in any partition. */
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static inline int
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var_to_partition (var_map map, tree var)
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{
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int part;
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part = partition_find (map->var_partition, SSA_NAME_VERSION (var));
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if (map->partition_to_view)
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part = map->partition_to_view[part];
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return part;
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}
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/* Given VAR, return the variable which represents the entire partition
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it is a member of in MAP. NULL is returned if it is not in a partition. */
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static inline tree
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var_to_partition_to_var (var_map map, tree var)
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{
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int part;
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part = var_to_partition (map, var);
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if (part == NO_PARTITION)
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return NULL_TREE;
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return partition_to_var (map, part);
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}
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/* Return the index into the basevar table for PARTITION's base in MAP. */
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static inline int
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basevar_index (var_map map, int partition)
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{
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gcc_checking_assert (partition >= 0
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&& partition <= (int) num_var_partitions (map));
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return map->partition_to_base_index[partition];
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}
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/* Return the number of different base variables in MAP. */
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static inline int
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num_basevars (var_map map)
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{
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return map->num_basevars;
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}
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/* ---------------- live on entry/exit info ------------------------------
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This structure is used to represent live range information on SSA based
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trees. A partition map must be provided, and based on the active partitions,
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live-on-entry information and live-on-exit information can be calculated.
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As well, partitions are marked as to whether they are global (live
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outside the basic block they are defined in).
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The live-on-entry information is per block. It provide a bitmap for
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each block which has a bit set for each partition that is live on entry to
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that block.
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The live-on-exit information is per block. It provides a bitmap for each
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block indicating which partitions are live on exit from the block.
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For the purposes of this implementation, we treat the elements of a PHI
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as follows:
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Uses in a PHI are considered LIVE-ON-EXIT to the block from which they
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originate. They are *NOT* considered live on entry to the block
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containing the PHI node.
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The Def of a PHI node is *not* considered live on entry to the block.
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It is considered to be "define early" in the block. Picture it as each
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block having a stmt (or block-preheader) before the first real stmt in
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the block which defines all the variables that are defined by PHIs.
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----------------------------------------------------------------------- */
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typedef struct tree_live_info_d
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{
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/* Var map this relates to. */
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var_map map;
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/* Bitmap indicating which partitions are global. */
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bitmap global;
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/* Bitmaps of live on entry blocks for partition elements. */
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bitmap_head *livein;
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/* Bitmaps of what variables are live on exit for a basic blocks. */
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bitmap_head *liveout;
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/* Number of basic blocks when live on exit calculated. */
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int num_blocks;
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/* Vector used when creating live ranges as a visited stack. */
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int *work_stack;
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/* Top of workstack. */
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int *stack_top;
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/* Obstacks to allocate the bitmaps on. */
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bitmap_obstack livein_obstack;
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bitmap_obstack liveout_obstack;
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} *tree_live_info_p;
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#define LIVEDUMP_ENTRY 0x01
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#define LIVEDUMP_EXIT 0x02
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#define LIVEDUMP_ALL (LIVEDUMP_ENTRY | LIVEDUMP_EXIT)
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extern void delete_tree_live_info (tree_live_info_p);
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extern tree_live_info_p calculate_live_ranges (var_map, bool);
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extern void debug (tree_live_info_d &ref);
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extern void debug (tree_live_info_d *ptr);
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extern void dump_live_info (FILE *, tree_live_info_p, int);
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typedef hash_map<int_hash <unsigned int, -1U>, unsigned int> live_vars_map;
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extern vec<bitmap_head> compute_live_vars (struct function *, live_vars_map *);
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extern bitmap live_vars_at_stmt (vec<bitmap_head> &, live_vars_map *,
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gimple *);
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extern void destroy_live_vars (vec<bitmap_head> &);
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/* Return TRUE if P is marked as a global in LIVE. */
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static inline int
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partition_is_global (tree_live_info_p live, int p)
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{
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gcc_checking_assert (live->global);
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return bitmap_bit_p (live->global, p);
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}
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/* Return the bitmap from LIVE representing the live on entry blocks for
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partition P. */
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static inline bitmap
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live_on_entry (tree_live_info_p live, basic_block bb)
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{
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gcc_checking_assert (live->livein
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&& bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)
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&& bb != EXIT_BLOCK_PTR_FOR_FN (cfun));
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return &live->livein[bb->index];
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}
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/* Return the bitmap from LIVE representing the live on exit partitions from
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block BB. */
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static inline bitmap
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live_on_exit (tree_live_info_p live, basic_block bb)
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{
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gcc_checking_assert (live->liveout
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&& bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)
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&& bb != EXIT_BLOCK_PTR_FOR_FN (cfun));
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return &live->liveout[bb->index];
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}
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/* Return the partition map which the information in LIVE utilizes. */
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static inline var_map
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live_var_map (tree_live_info_p live)
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{
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return live->map;
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}
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/* Mark partition P as live on entry to basic block BB in LIVE. */
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static inline void
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make_live_on_entry (tree_live_info_p live, basic_block bb , int p)
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{
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bitmap_set_bit (&live->livein[bb->index], p);
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bitmap_set_bit (live->global, p);
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}
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#endif /* _TREE_SSA_LIVE_H */
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