[gcc.git] / gcc / regs.h

/* Define per-register tables for data flow info and register allocation.
   Copyright (C) 1987, 93-99, 2000 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC 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 2, or (at your option)
any later version.

GNU CC 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 GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */


#include "varray.h"

#define REG_BYTES(R) mode_size[(int) GET_MODE (R)]

/* Get the number of consecutive hard regs required to hold the REG rtx R.
   When something may be an explicit hard reg, REG_SIZE is the only
   valid way to get this value.  You cannot get it from the regno.  */

#define REG_SIZE(R) \
  ((mode_size[(int) GET_MODE (R)] + UNITS_PER_WORD - 1) / UNITS_PER_WORD)

#ifndef SMALL_REGISTER_CLASSES
#define SMALL_REGISTER_CLASSES 0
#endif

/* Maximum register number used in this function, plus one.  */

extern int max_regno;

/* Register information indexed by register number */
typedef struct reg_info_def
{				/* fields set by reg_scan */
  int first_uid;		/* UID of first insn to use (REG n) */
  int last_uid;			/* UID of last insn to use (REG n) */
  int last_note_uid;		/* UID of last note to use (REG n) */

				/* fields set by reg_scan & flow_analysis */
  int sets;			/* # of times (REG n) is set */

				/* fields set by flow_analysis */
  int refs;			/* # of times (REG n) is used or set */
  int deaths;			/* # of times (REG n) dies */
  int live_length;		/* # of instructions (REG n) is live */
  int calls_crossed;		/* # of calls (REG n) is live across */
  int basic_block;		/* # of basic blocks (REG n) is used in */
  char changes_size;		/* whether (SUBREG (REG n)) changes size */
} reg_info;

extern varray_type reg_n_info;

extern unsigned int reg_n_max;

/* Indexed by n, gives number of times (REG n) is used or set.
   References within loops may be counted more times.  */

#define REG_N_REFS(N) (VARRAY_REG (reg_n_info, N)->refs)

/* Indexed by n, gives number of times (REG n) is set.
   ??? both regscan and flow allocate space for this.  We should settle
   on just copy.  */

#define REG_N_SETS(N) (VARRAY_REG (reg_n_info, N)->sets)

/* Indexed by N, gives number of insns in which register N dies.
   Note that if register N is live around loops, it can die
   in transitions between basic blocks, and that is not counted here.
   So this is only a reliable indicator of how many regions of life there are
   for registers that are contained in one basic block.  */

#define REG_N_DEATHS(N) (VARRAY_REG (reg_n_info, N)->deaths)

/* Indexed by N; says whether a pseudo register N was ever used
   within a SUBREG that changes the size of the reg.  Some machines prohibit
   such objects to be in certain (usually floating-point) registers.  */

#define REG_CHANGES_SIZE(N) (VARRAY_REG (reg_n_info, N)->changes_size)

/* Get the number of consecutive words required to hold pseudo-reg N.  */

#define PSEUDO_REGNO_SIZE(N) \
  ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1)		\
   / UNITS_PER_WORD)

/* Get the number of bytes required to hold pseudo-reg N.  */

#define PSEUDO_REGNO_BYTES(N) \
  GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))

/* Get the machine mode of pseudo-reg N.  */

#define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])

/* Indexed by N, gives number of CALL_INSNS across which (REG n) is live.  */

#define REG_N_CALLS_CROSSED(N) (VARRAY_REG (reg_n_info, N)->calls_crossed)

/* Total number of instructions at which (REG n) is live.
   The larger this is, the less priority (REG n) gets for
   allocation in a hard register (in global-alloc).
   This is set in flow.c and remains valid for the rest of the compilation
   of the function; it is used to control register allocation.

   local-alloc.c may alter this number to change the priority.

   Negative values are special.
   -1 is used to mark a pseudo reg which has a constant or memory equivalent
   and is used infrequently enough that it should not get a hard register.
   -2 is used to mark a pseudo reg for a parameter, when a frame pointer
   is not required.  global.c makes an allocno for this but does
   not try to assign a hard register to it.  */

#define REG_LIVE_LENGTH(N) (VARRAY_REG (reg_n_info, N)->live_length)

/* Vector of substitutions of register numbers,
   used to map pseudo regs into hardware regs.

   This can't be folded into reg_n_info without changing all of the
   machine dependent directories, since the reload functions
   in the machine dependent files access it.  */

extern short *reg_renumber;

/* Vector indexed by hardware reg
   saying whether that reg is ever used.  */

extern char regs_ever_live[FIRST_PSEUDO_REGISTER];

/* Vector indexed by hardware reg giving its name.  */

extern const char *reg_names[FIRST_PSEUDO_REGISTER];

/* For each hard register, the widest mode object that it can contain.
   This will be a MODE_INT mode if the register can hold integers.  Otherwise
   it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
   register.  */

extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER];

/* Vector indexed by regno; gives uid of first insn using that reg.
   This is computed by reg_scan for use by cse and loop.
   It is sometimes adjusted for subsequent changes during loop,
   but not adjusted by cse even if cse invalidates it.  */

#define REGNO_FIRST_UID(N) (VARRAY_REG (reg_n_info, N)->first_uid)

/* Vector indexed by regno; gives uid of last insn using that reg.
   This is computed by reg_scan for use by cse and loop.
   It is sometimes adjusted for subsequent changes during loop,
   but not adjusted by cse even if cse invalidates it.
   This is harmless since cse won't scan through a loop end.  */

#define REGNO_LAST_UID(N) (VARRAY_REG (reg_n_info, N)->last_uid)

/* Similar, but includes insns that mention the reg in their notes.  */

#define REGNO_LAST_NOTE_UID(N) (VARRAY_REG (reg_n_info, N)->last_note_uid)

/* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
   that have to go in the same hard reg.  */
extern rtx regs_may_share;

/* Flag set by local-alloc or global-alloc if they decide to allocate
   something in a call-clobbered register.  */

extern int caller_save_needed;

/* Predicate to decide whether to give a hard reg to a pseudo which
   is referenced REFS times and would need to be saved and restored
   around a call CALLS times.  */

#ifndef CALLER_SAVE_PROFITABLE
#define CALLER_SAVE_PROFITABLE(REFS, CALLS)  (4 * (CALLS) < (REFS))
#endif

/* On most machines a register class is likely to be spilled if it
   only has one register.  */
#ifndef CLASS_LIKELY_SPILLED_P
#define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1)
#endif

/* Select a register mode required for caller save of hard regno REGNO.  */
#ifndef HARD_REGNO_CALLER_SAVE_MODE
#define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS) \
  choose_hard_reg_mode (REGNO, NREGS)
#endif

/* Registers that get partially clobbered by a call in a given mode. 
   These must not be call used registers.  */
#ifndef HARD_REGNO_CALL_PART_CLOBBERED
#define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0
#endif

/* Allocate reg_n_info tables */
extern void allocate_reg_info PARAMS ((size_t, int, int));
Commit	Line	Data
c3bcc836	1	/* Define per-register tables for data flow info and register allocation.
9311a396	2	Copyright (C) 1987, 93-99, 2000 Free Software Foundation, Inc.
c3bcc836 RK	3
	4	This file is part of GNU CC.
	5
	6	GNU CC is free software; you can redistribute it and/or modify
	7	it under the terms of the GNU General Public License as published by
	8	the Free Software Foundation; either version 2, or (at your option)
	9	any later version.
	10
	11	GNU CC is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	GNU General Public License for more details.
	15
	16	You should have received a copy of the GNU General Public License
	17	along with GNU CC; see the file COPYING. If not, write to
e99215a3 RK	18	the Free Software Foundation, 59 Temple Place - Suite 330,
e99215a3 RK	19	Boston, MA 02111-1307, USA. */
c3bcc836 RK	20
c3bcc836 RK	21
6feacd09	22	#include "varray.h"
c3bcc836 RK	23
	24	#define REG_BYTES(R) mode_size[(int) GET_MODE (R)]
	25
	26	/* Get the number of consecutive hard regs required to hold the REG rtx R.
	27	When something may be an explicit hard reg, REG_SIZE is the only
	28	valid way to get this value. You cannot get it from the regno. */
	29
	30	#define REG_SIZE(R) \
	31	((mode_size[(int) GET_MODE (R)] + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
	32
31031edd JL	33	#ifndef SMALL_REGISTER_CLASSES
	34	#define SMALL_REGISTER_CLASSES 0
	35	#endif
	36
c3bcc836 RK	37	/* Maximum register number used in this function, plus one. */
	38
	39	extern int max_regno;
	40
b1f21e0a	41	/* Register information indexed by register number */
d4b60170 RK	42	typedef struct reg_info_def
d4b60170 RK	43	{ /* fields set by reg_scan */
b1f21e0a MM	44	int first_uid; /* UID of first insn to use (REG n) */
	45	int last_uid; /* UID of last insn to use (REG n) */
	46	int last_note_uid; /* UID of last note to use (REG n) */
	47
d4b60170	48	/* fields set by reg_scan & flow_analysis */
b1f21e0a MM	49	int sets; /* # of times (REG n) is set */
	50
	51	/* fields set by flow_analysis */
	52	int refs; /* # of times (REG n) is used or set */
	53	int deaths; /* # of times (REG n) dies */
	54	int live_length; /* # of instructions (REG n) is live */
	55	int calls_crossed; /* # of calls (REG n) is live across */
	56	int basic_block; /* # of basic blocks (REG n) is used in */
	57	char changes_size; /* whether (SUBREG (REG n)) changes size */
	58	} reg_info;
	59
6feacd09	60	extern varray_type reg_n_info;
b1f21e0a	61
a494747c MM	62	extern unsigned int reg_n_max;
a494747c MM	63
c3bcc836 RK	64	/* Indexed by n, gives number of times (REG n) is used or set.
	65	References within loops may be counted more times. */
	66
6feacd09	67	#define REG_N_REFS(N) (VARRAY_REG (reg_n_info, N)->refs)
c3bcc836	68
b1f21e0a MM	69	/* Indexed by n, gives number of times (REG n) is set.
	70	??? both regscan and flow allocate space for this. We should settle
	71	on just copy. */
c3bcc836	72
6feacd09	73	#define REG_N_SETS(N) (VARRAY_REG (reg_n_info, N)->sets)
c3bcc836 RK	74
	75	/* Indexed by N, gives number of insns in which register N dies.
	76	Note that if register N is live around loops, it can die
	77	in transitions between basic blocks, and that is not counted here.
	78	So this is only a reliable indicator of how many regions of life there are
	79	for registers that are contained in one basic block. */
	80
6feacd09	81	#define REG_N_DEATHS(N) (VARRAY_REG (reg_n_info, N)->deaths)
c3bcc836	82
9faa82d8	83	/* Indexed by N; says whether a pseudo register N was ever used
ffceec83 RK	84	within a SUBREG that changes the size of the reg. Some machines prohibit
	85	such objects to be in certain (usually floating-point) registers. */
	86
6feacd09	87	#define REG_CHANGES_SIZE(N) (VARRAY_REG (reg_n_info, N)->changes_size)
ffceec83	88
c3bcc836 RK	89	/* Get the number of consecutive words required to hold pseudo-reg N. */
	90
	91	#define PSEUDO_REGNO_SIZE(N) \
	92	((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1) \
	93	/ UNITS_PER_WORD)
	94
	95	/* Get the number of bytes required to hold pseudo-reg N. */
	96
	97	#define PSEUDO_REGNO_BYTES(N) \
	98	GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
	99
	100	/* Get the machine mode of pseudo-reg N. */
	101
	102	#define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
	103
	104	/* Indexed by N, gives number of CALL_INSNS across which (REG n) is live. */
	105
6feacd09	106	#define REG_N_CALLS_CROSSED(N) (VARRAY_REG (reg_n_info, N)->calls_crossed)
c3bcc836 RK	107
	108	/* Total number of instructions at which (REG n) is live.
	109	The larger this is, the less priority (REG n) gets for
	110	allocation in a hard register (in global-alloc).
	111	This is set in flow.c and remains valid for the rest of the compilation
	112	of the function; it is used to control register allocation.
	113
	114	local-alloc.c may alter this number to change the priority.
	115
	116	Negative values are special.
	117	-1 is used to mark a pseudo reg which has a constant or memory equivalent
	118	and is used infrequently enough that it should not get a hard register.
	119	-2 is used to mark a pseudo reg for a parameter, when a frame pointer
cfb2c0b1	120	is not required. global.c makes an allocno for this but does
c3bcc836 RK	121	not try to assign a hard register to it. */
c3bcc836 RK	122
6feacd09	123	#define REG_LIVE_LENGTH(N) (VARRAY_REG (reg_n_info, N)->live_length)
c3bcc836 RK	124
c3bcc836 RK	125	/* Vector of substitutions of register numbers,
b1f21e0a MM	126	used to map pseudo regs into hardware regs.
	127
	128	This can't be folded into reg_n_info without changing all of the
	129	machine dependent directories, since the reload functions
39379e67	130	in the machine dependent files access it. */
c3bcc836 RK	131
	132	extern short *reg_renumber;
	133
	134	/* Vector indexed by hardware reg
	135	saying whether that reg is ever used. */
	136
	137	extern char regs_ever_live[FIRST_PSEUDO_REGISTER];
	138
	139	/* Vector indexed by hardware reg giving its name. */
	140
99f44eba	141	extern const char *reg_names[FIRST_PSEUDO_REGISTER];
c3bcc836	142
04569dfb DE	143	/* For each hard register, the widest mode object that it can contain.
	144	This will be a MODE_INT mode if the register can hold integers. Otherwise
	145	it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
	146	register. */
	147
	148	extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER];
	149
c3bcc836 RK	150	/* Vector indexed by regno; gives uid of first insn using that reg.
	151	This is computed by reg_scan for use by cse and loop.
	152	It is sometimes adjusted for subsequent changes during loop,
	153	but not adjusted by cse even if cse invalidates it. */
	154
6feacd09	155	#define REGNO_FIRST_UID(N) (VARRAY_REG (reg_n_info, N)->first_uid)
c3bcc836 RK	156
	157	/* Vector indexed by regno; gives uid of last insn using that reg.
	158	This is computed by reg_scan for use by cse and loop.
	159	It is sometimes adjusted for subsequent changes during loop,
	160	but not adjusted by cse even if cse invalidates it.
	161	This is harmless since cse won't scan through a loop end. */
	162
6feacd09	163	#define REGNO_LAST_UID(N) (VARRAY_REG (reg_n_info, N)->last_uid)
c3bcc836	164
2cb547d8 RS	165	/* Similar, but includes insns that mention the reg in their notes. */
2cb547d8 RS	166
6feacd09	167	#define REGNO_LAST_NOTE_UID(N) (VARRAY_REG (reg_n_info, N)->last_note_uid)
2cb547d8	168
c3bcc836 RK	169	/* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
	170	that have to go in the same hard reg. */
	171	extern rtx regs_may_share;
	172
c3bcc836 RK	173	/* Flag set by local-alloc or global-alloc if they decide to allocate
	174	something in a call-clobbered register. */
	175
	176	extern int caller_save_needed;
	177
	178	/* Predicate to decide whether to give a hard reg to a pseudo which
	179	is referenced REFS times and would need to be saved and restored
	180	around a call CALLS times. */
	181
	182	#ifndef CALLER_SAVE_PROFITABLE
	183	#define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS))
	184	#endif
a65b6597	185
6cad67d2 JL	186	/* On most machines a register class is likely to be spilled if it
	187	only has one register. */
	188	#ifndef CLASS_LIKELY_SPILLED_P
	189	#define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1)
	190	#endif
	191
8d5c8167 JL	192	/* Select a register mode required for caller save of hard regno REGNO. */
	193	#ifndef HARD_REGNO_CALLER_SAVE_MODE
	194	#define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS) \
	195	choose_hard_reg_mode (REGNO, NREGS)
	196	#endif
	197
1e326708 MH	198	/* Registers that get partially clobbered by a call in a given mode.
	199	These must not be call used registers. */
	200	#ifndef HARD_REGNO_CALL_PART_CLOBBERED
	201	#define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0
	202	#endif
	203
b1f21e0a	204	/* Allocate reg_n_info tables */
13536812	205	extern void allocate_reg_info PARAMS ((size_t, int, int));