[gcc.git] / gcc / regs.h

/* Define per-register tables for data flow info and register allocation.
   Copyright (C) 1987, 1993, 1994, 1995, 1997 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.  */


#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;

/* Maximum number of SCRATCH rtx's in each block of this function.  */

extern int max_scratch;

/* 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 both reg_scan and 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 reg_info *reg_n_info;

extern unsigned int reg_n_max;

/* Check for REG_N_xxx macros being in bound, return N for use as an
   index.  */
#ifdef ENABLE_CHECKING
#define REG_N_CHECK(N)							\
((((unsigned)(N) < (unsigned)reg_n_max)					\
 ? 0 : (fatal ("Register %d out of bounds", (N)), 0)), (N))
#else
#define REG_N_CHECK(N) (N)
#endif

/* 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) (reg_n_info[REG_N_CHECK (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) (reg_n_info[REG_N_CHECK (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) (reg_n_info[REG_N_CHECK (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) (reg_n_info[REG_N_CHECK (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) (reg_n_info[REG_N_CHECK (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) (reg_n_info[REG_N_CHECK (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 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) (reg_n_info[REG_N_CHECK (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) (reg_n_info[REG_N_CHECK (N)].last_uid)

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

#define REGNO_LAST_NOTE_UID(N) (reg_n_info[REG_N_CHECK (N)].last_note_uid)

/* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
   After rtl generation, it is 1 plus the largest register number used.  */

extern int reg_rtx_no;

/* Vector indexed by regno; contains 1 for a register is considered a pointer.
   Reloading, etc. will use a pointer register rather than a non-pointer
   as the base register in an address, when there is a choice of two regs.  */

extern char *regno_pointer_flag;
#define REGNO_POINTER_FLAG(REGNO) regno_pointer_flag[REGNO]
extern int regno_pointer_flag_length;

/* 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;

/* Vector mapping pseudo regno into the REG rtx for that register.
   This is computed by reg_scan.  */

extern rtx *regno_reg_rtx;

/* 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

/* Allocated in local_alloc.  */

/* A list of SCRATCH rtl allocated by local-alloc.  */
extern rtx *scratch_list;
/* The basic block in which each SCRATCH is used.  */
extern int *scratch_block;
/* The length of the arrays pointed to by scratch_block and scratch_list.  */
extern int scratch_list_length;

/* Allocate reg_n_info tables */
extern void allocate_reg_info PROTO((int, int, int));
Commit	Line	Data
c3bcc836	1	/* Define per-register tables for data flow info and register allocation.
39379e67	2	Copyright (C) 1987, 1993, 1994, 1995, 1997 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
	21
	22
	23	#define REG_BYTES(R) mode_size[(int) GET_MODE (R)]
	24
	25	/* Get the number of consecutive hard regs required to hold the REG rtx R.
	26	When something may be an explicit hard reg, REG_SIZE is the only
	27	valid way to get this value. You cannot get it from the regno. */
	28
	29	#define REG_SIZE(R) \
	30	((mode_size[(int) GET_MODE (R)] + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
	31
31031edd JL	32	#ifndef SMALL_REGISTER_CLASSES
	33	#define SMALL_REGISTER_CLASSES 0
	34	#endif
	35
c3bcc836 RK	36	/* Maximum register number used in this function, plus one. */
	37
	38	extern int max_regno;
	39
	40	/* Maximum number of SCRATCH rtx's in each block of this function. */
	41
	42	extern int max_scratch;
	43
b1f21e0a MM	44	/* Register information indexed by register number */
	45	typedef struct reg_info_def {
	46	/* fields set by reg_scan */
	47	int first_uid; /* UID of first insn to use (REG n) */
	48	int last_uid; /* UID of last insn to use (REG n) */
	49	int last_note_uid; /* UID of last note to use (REG n) */
	50
	51	/* fields set by both reg_scan and flow_analysis */
	52	int sets; /* # of times (REG n) is set */
	53
	54	/* fields set by flow_analysis */
	55	int refs; /* # of times (REG n) is used or set */
	56	int deaths; /* # of times (REG n) dies */
	57	int live_length; /* # of instructions (REG n) is live */
	58	int calls_crossed; /* # of calls (REG n) is live across */
	59	int basic_block; /* # of basic blocks (REG n) is used in */
	60	char changes_size; /* whether (SUBREG (REG n)) changes size */
	61	} reg_info;
	62
	63	extern reg_info *reg_n_info;
	64
a494747c MM	65	extern unsigned int reg_n_max;
	66
	67	/* Check for REG_N_xxx macros being in bound, return N for use as an
	68	index. */
	69	#ifdef ENABLE_CHECKING
	70	#define REG_N_CHECK(N) \
	71	((((unsigned)(N) < (unsigned)reg_n_max) \
	72	? 0 : (fatal ("Register %d out of bounds", (N)), 0)), (N))
	73	#else
	74	#define REG_N_CHECK(N) (N)
	75	#endif
	76
c3bcc836 RK	77	/* Indexed by n, gives number of times (REG n) is used or set.
	78	References within loops may be counted more times. */
	79
a494747c	80	#define REG_N_REFS(N) (reg_n_info[REG_N_CHECK (N)].refs)
c3bcc836	81
b1f21e0a MM	82	/* Indexed by n, gives number of times (REG n) is set.
	83	??? both regscan and flow allocate space for this. We should settle
	84	on just copy. */
c3bcc836	85
a494747c	86	#define REG_N_SETS(N) (reg_n_info[REG_N_CHECK (N)].sets)
c3bcc836 RK	87
	88	/* Indexed by N, gives number of insns in which register N dies.
	89	Note that if register N is live around loops, it can die
	90	in transitions between basic blocks, and that is not counted here.
	91	So this is only a reliable indicator of how many regions of life there are
	92	for registers that are contained in one basic block. */
	93
a494747c	94	#define REG_N_DEATHS(N) (reg_n_info[REG_N_CHECK (N)].deaths)
c3bcc836	95
9faa82d8	96	/* Indexed by N; says whether a pseudo register N was ever used
ffceec83 RK	97	within a SUBREG that changes the size of the reg. Some machines prohibit
	98	such objects to be in certain (usually floating-point) registers. */
	99
a494747c	100	#define REG_CHANGES_SIZE(N) (reg_n_info[REG_N_CHECK (N)].changes_size)
ffceec83	101
c3bcc836 RK	102	/* Get the number of consecutive words required to hold pseudo-reg N. */
	103
	104	#define PSEUDO_REGNO_SIZE(N) \
	105	((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1) \
	106	/ UNITS_PER_WORD)
	107
	108	/* Get the number of bytes required to hold pseudo-reg N. */
	109
	110	#define PSEUDO_REGNO_BYTES(N) \
	111	GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
	112
	113	/* Get the machine mode of pseudo-reg N. */
	114
	115	#define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
	116
	117	/* Indexed by N, gives number of CALL_INSNS across which (REG n) is live. */
	118
a494747c	119	#define REG_N_CALLS_CROSSED(N) (reg_n_info[REG_N_CHECK (N)].calls_crossed)
c3bcc836 RK	120
	121	/* Total number of instructions at which (REG n) is live.
	122	The larger this is, the less priority (REG n) gets for
	123	allocation in a hard register (in global-alloc).
	124	This is set in flow.c and remains valid for the rest of the compilation
	125	of the function; it is used to control register allocation.
	126
	127	local-alloc.c may alter this number to change the priority.
	128
	129	Negative values are special.
	130	-1 is used to mark a pseudo reg which has a constant or memory equivalent
	131	and is used infrequently enough that it should not get a hard register.
	132	-2 is used to mark a pseudo reg for a parameter, when a frame pointer
cfb2c0b1	133	is not required. global.c makes an allocno for this but does
c3bcc836 RK	134	not try to assign a hard register to it. */
c3bcc836 RK	135
a494747c	136	#define REG_LIVE_LENGTH(N) (reg_n_info[REG_N_CHECK (N)].live_length)
c3bcc836 RK	137
c3bcc836 RK	138	/* Vector of substitutions of register numbers,
b1f21e0a MM	139	used to map pseudo regs into hardware regs.
	140
	141	This can't be folded into reg_n_info without changing all of the
	142	machine dependent directories, since the reload functions
39379e67	143	in the machine dependent files access it. */
c3bcc836 RK	144
	145	extern short *reg_renumber;
	146
	147	/* Vector indexed by hardware reg
	148	saying whether that reg is ever used. */
	149
	150	extern char regs_ever_live[FIRST_PSEUDO_REGISTER];
	151
	152	/* Vector indexed by hardware reg giving its name. */
	153
	154	extern char *reg_names[FIRST_PSEUDO_REGISTER];
	155
04569dfb DE	156	/* For each hard register, the widest mode object that it can contain.
	157	This will be a MODE_INT mode if the register can hold integers. Otherwise
	158	it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
	159	register. */
	160
	161	extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER];
	162
c3bcc836 RK	163	/* Vector indexed by regno; gives uid of first insn using that reg.
	164	This is computed by reg_scan for use by cse and loop.
	165	It is sometimes adjusted for subsequent changes during loop,
	166	but not adjusted by cse even if cse invalidates it. */
	167
a494747c	168	#define REGNO_FIRST_UID(N) (reg_n_info[REG_N_CHECK (N)].first_uid)
c3bcc836 RK	169
	170	/* Vector indexed by regno; gives uid of last insn using that reg.
	171	This is computed by reg_scan for use by cse and loop.
	172	It is sometimes adjusted for subsequent changes during loop,
	173	but not adjusted by cse even if cse invalidates it.
	174	This is harmless since cse won't scan through a loop end. */
	175
a494747c	176	#define REGNO_LAST_UID(N) (reg_n_info[REG_N_CHECK (N)].last_uid)
c3bcc836	177
2cb547d8 RS	178	/* Similar, but includes insns that mention the reg in their notes. */
2cb547d8 RS	179
a494747c	180	#define REGNO_LAST_NOTE_UID(N) (reg_n_info[REG_N_CHECK (N)].last_note_uid)
2cb547d8	181
40f954f6 RK	182	/* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
	183	After rtl generation, it is 1 plus the largest register number used. */
	184
	185	extern int reg_rtx_no;
	186
c3bcc836 RK	187	/* Vector indexed by regno; contains 1 for a register is considered a pointer.
	188	Reloading, etc. will use a pointer register rather than a non-pointer
	189	as the base register in an address, when there is a choice of two regs. */
	190
	191	extern char *regno_pointer_flag;
	192	#define REGNO_POINTER_FLAG(REGNO) regno_pointer_flag[REGNO]
40f954f6 RK	193	extern int regno_pointer_flag_length;
40f954f6 RK	194
c3bcc836 RK	195	/* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
	196	that have to go in the same hard reg. */
	197	extern rtx regs_may_share;
	198
	199	/* Vector mapping pseudo regno into the REG rtx for that register.
	200	This is computed by reg_scan. */
	201
	202	extern rtx *regno_reg_rtx;
	203
	204	/* Flag set by local-alloc or global-alloc if they decide to allocate
	205	something in a call-clobbered register. */
	206
	207	extern int caller_save_needed;
	208
	209	/* Predicate to decide whether to give a hard reg to a pseudo which
	210	is referenced REFS times and would need to be saved and restored
	211	around a call CALLS times. */
	212
	213	#ifndef CALLER_SAVE_PROFITABLE
	214	#define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS))
	215	#endif
a65b6597	216
6cad67d2 JL	217	/* On most machines a register class is likely to be spilled if it
	218	only has one register. */
	219	#ifndef CLASS_LIKELY_SPILLED_P
	220	#define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1)
	221	#endif
	222
a65b6597 RK	223	/* Allocated in local_alloc. */
	224
	225	/* A list of SCRATCH rtl allocated by local-alloc. */
	226	extern rtx *scratch_list;
	227	/* The basic block in which each SCRATCH is used. */
	228	extern int *scratch_block;
	229	/* The length of the arrays pointed to by scratch_block and scratch_list. */
	230	extern int scratch_list_length;
b1f21e0a MM	231
b1f21e0a MM	232	/* Allocate reg_n_info tables */
39379e67	233	extern void allocate_reg_info PROTO((int, int, int));