#include "partition.h"

Include dependency graph for tree-ssa-live.h:

This graph shows which files directly or indirectly include this file:

Data Structures
struct	_var_map
struct	tree_live_info_d

Macros
#define	NO_PARTITION -1
#define	LIVEDUMP_ENTRY 0x01
#define	LIVEDUMP_EXIT 0x02
#define	LIVEDUMP_ALL (LIVEDUMP_ENTRY \| LIVEDUMP_EXIT)

Typedefs
typedef struct _var_map *	var_map
typedef struct tree_live_info_d *	tree_live_info_p

Functions
var_map	init_var_map (int)
void	delete_var_map (var_map)
int	var_union (var_map, tree, tree)
void	partition_view_normal (var_map, bool)
void	partition_view_bitmap (var_map, bitmap, bool)
void	dump_scope_blocks (FILE *, int)
void	debug_scope_block (tree, int)
void	debug_scope_blocks (int)
void	remove_unused_locals (void)
void	dump_var_map (FILE *, var_map)
void	debug (_var_map &ref)
void	debug (_var_map *ptr)
static unsigned	num_var_partitions ()
static tree	partition_to_var ()
static tree	version_to_var ()
static int	var_to_partition ()
static tree	var_to_partition_to_var ()
static int	basevar_index ()
static int	num_basevars ()
static void	register_ssa_partition (var_map map, tree ssa_var)
void	delete_tree_live_info (tree_live_info_p)
void	calculate_live_on_exit (tree_live_info_p)
tree_live_info_p	calculate_live_ranges (var_map)
void	debug (tree_live_info_d &ref)
void	debug (tree_live_info_d *ptr)
void	dump_live_info (FILE *, tree_live_info_p, int)
static int	partition_is_global ()
static bitmap	live_on_entry ()
static bitmap	live_on_exit ()
static var_map	live_var_map ()
static void	live_merge_and_clear ()
static void	make_live_on_entry ()

Macro Definition Documentation

#define LIVEDUMP_ALL (LIVEDUMP_ENTRY | LIVEDUMP_EXIT)

#define LIVEDUMP_ENTRY 0x01

#define LIVEDUMP_EXIT 0x02

#define NO_PARTITION -1

Value used to represent no partition number.

Referenced by add_dependence(), eliminate_useless_phis(), loe_visit_block(), partition_to_var(), set_var_live_on_entry(), and var_to_partition().

Typedef Documentation

typedef struct tree_live_info_d * tree_live_info_p

—————- live on entry/exit info ——————————

This structure is used to represent live range information on SSA based trees. A partition map must be provided, and based on the active partitions, live-on-entry information and live-on-exit information can be calculated. As well, partitions are marked as to whether they are global (live outside the basic block they are defined in).

The live-on-entry information is per block. It provide a bitmap for each block which has a bit set for each partition that is live on entry to that block.

The live-on-exit information is per block. It provides a bitmap for each block indicating which partitions are live on exit from the block.

For the purposes of this implementation, we treat the elements of a PHI as follows:

Uses in a PHI are considered LIVE-ON-EXIT to the block from which they originate. They are NOT considered live on entry to the block containing the PHI node.

The Def of a PHI node is not considered live on entry to the block. It is considered to be "define early" in the block. Picture it as each block having a stmt (or block-preheader) before the first real stmt in the block which defines all the variables that are defined by PHIs.

———————————————————————–

typedef struct _var_map * var_map

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see http://www.gnu.org/licenses/. Used to create the variable mapping when we go out of SSA form.

Mapping from an ssa_name to a partition number is maintained, as well as partition number back to ssa_name.

This data structure also supports "views", which work on a subset of all partitions. This allows the coalescer to decide what partitions are interesting to it, and only work with those partitions. Whenever the view is changed, the partition numbers change, but none of the partition groupings change. (ie, it is truly a view since it doesn't change anything)

The final component of the data structure is the basevar map. This provides a list of all the different base variables which occur in a partition view, and a unique index for each one. Routines are provided to quickly produce the base variable of a partition.

Note that members of a partition MUST all have the same base variable.

Function Documentation

static int basevar_index ( )

inlinestatic

Return the index into the basevar table for PARTITION's base in MAP.

Referenced by live_track_remove_partition(), and new_live_track().

void calculate_live_on_exit ( tree_live_info_p )

tree_live_info_p calculate_live_ranges ( var_map )

void debug ( _var_map & ref )

void debug ( _var_map * ptr )

void debug ( tree_live_info_d & ref )

void debug ( tree_live_info_d * ptr )

void debug_scope_block	(	tree	,
		int
	)

void debug_scope_blocks ( int )

void delete_tree_live_info ( tree_live_info_p )

void delete_var_map ( var_map )

void dump_live_info	(	FILE *	,
		tree_live_info_p	,
		int
	)

void dump_scope_blocks	(	FILE *	,
		int
	)

void dump_var_map	(	FILE *	,
		var_map
	)

var_map init_var_map ( int )

static void live_merge_and_clear ( )

inlinestatic

Merge the live on entry information in LIVE for partitions P1 and P2. Place the result into P1. Clear P2.

static bitmap live_on_entry ( )

inlinestatic

Return the bitmap from LIVE representing the live on entry blocks for partition P.

References tree_live_info_d::map.

Referenced by dump_live_info(), and set_var_live_on_entry().

static bitmap live_on_exit ( )

inlinestatic

Return the bitmap from LIVE representing the live on exit partitions from block BB.

static var_map live_var_map ( )

inlinestatic

Return the partition map which the information in LIVE utilizes.

static void make_live_on_entry ( )

inlinestatic

Mark partition P as live on entry to basic block BB in LIVE.

static int num_basevars ( )

inlinestatic

Return the number of different base variables in MAP.

static unsigned num_var_partitions ( )

inlinestatic

Return number of partitions in MAP.

References ssa_name, _var_map::var_partition, and _var_map::view_to_partition.

Referenced by coalesce_partitions(), dump_live_info(), and var_to_partition_to_var().

static int partition_is_global ( )

inlinestatic

Return TRUE if P is marked as a global in LIVE.

References ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, gcc_checking_assert, basic_block_def::index, and tree_live_info_d::liveout.

static tree partition_to_var ( )

inlinestatic

Given partition index I from MAP, return the variable which represents that partition.

References NO_PARTITION, NULL_TREE, _var_map::partition_to_view, and _var_map::var_partition.

Referenced by calculate_live_on_exit(), dump_live_info(), dump_var_map(), elim_unvisited_predecessor(), insert_rtx_to_part_on_edge(), and var_to_partition().

void partition_view_bitmap	(	var_map	,
		bitmap	,
		bool
	)

void partition_view_normal	(	var_map	,
		bool
	)

static void register_ssa_partition	(	var_map	map,
		tree	ssa_var
	)

inlinestatic

This routine registers a partition for SSA_VAR with MAP. Any unregistered partitions may be filtered out by a view later.

References tree_live_info_d::global, tree_live_info_d::livein, tree_live_info_d::liveout, tree_live_info_d::map, and tree_live_info_d::num_blocks.

void remove_unused_locals ( void )

Remove local variables that are not referenced in the IL.

 Removing declarations from lexical blocks when not optimizing is
 not only a waste of time, it actually causes differences in stack
 layout.

 Walk the CFG marking all referenced symbols.

     Walk the statements.

 We do a two-pass approach about the out-of-scope clobbers.  We want
 to remove them if they are the only references to a local variable,
 but we want to retain them when there's any other.  So the first pass
 ignores them, and the second pass (if there were any) tries to remove
 them.

               Remove clobbers referencing unused vars, or clobbers
               with MEM_REF lhs referencing uninitialized pointers.

 Remove unmarked local and global vars from local_decls.

             Release any default def associated with var.

static int var_to_partition ( )

inlinestatic

Given VAR, return the partition number in MAP which contains it. NO_PARTITION is returned if it's not in any partition.

References NO_PARTITION, NULL_TREE, and partition_to_var().

Referenced by add_dependence(), eliminate_useless_phis(), loe_visit_block(), and set_var_live_on_entry().

static tree var_to_partition_to_var ( )

inlinestatic

Given VAR, return the variable which represents the entire partition it is a member of in MAP. NULL is returned if it is not in a partition.

References gcc_checking_assert, num_var_partitions(), and _var_map::partition_to_base_index.

Referenced by eliminate_useless_phis().

int var_union	(	var_map	,
		tree	,
		tree
	)

static tree version_to_var ( )

inlinestatic

Given ssa_name VERSION, if it has a partition in MAP, return the var it is associated with. Otherwise return NULL.

References _var_map::partition_to_view, SSA_NAME_VERSION, and _var_map::var_partition.

Data Structures

Macros

Typedefs

Functions

Macro Definition Documentation

Typedef Documentation

Function Documentation