regs.h revision 52284
1/* Define per-register tables for data flow info and register allocation. 2 Copyright (C) 1987, 1993, 1994, 1995, 1997, 1998 Free Software Foundation, Inc. 3 4This file is part of GNU CC. 5 6GNU CC is free software; you can redistribute it and/or modify 7it under the terms of the GNU General Public License as published by 8the Free Software Foundation; either version 2, or (at your option) 9any later version. 10 11GNU CC is distributed in the hope that it will be useful, 12but WITHOUT ANY WARRANTY; without even the implied warranty of 13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14GNU General Public License for more details. 15 16You should have received a copy of the GNU General Public License 17along with GNU CC; see the file COPYING. If not, write to 18the Free Software Foundation, 59 Temple Place - Suite 330, 19Boston, MA 02111-1307, USA. */ 20 21 22#include "varray.h" 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 33#ifndef SMALL_REGISTER_CLASSES 34#define SMALL_REGISTER_CLASSES 0 35#endif 36 37/* Maximum register number used in this function, plus one. */ 38 39extern int max_regno; 40 41/* Register information indexed by register number */ 42typedef struct reg_info_def { 43 /* fields set by reg_scan */ 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 48 /* fields set by both reg_scan and flow_analysis */ 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 60extern varray_type reg_n_info; 61 62extern unsigned int reg_n_max; 63 64/* Indexed by n, gives number of times (REG n) is used or set. 65 References within loops may be counted more times. */ 66 67#define REG_N_REFS(N) (VARRAY_REG (reg_n_info, N)->refs) 68 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. */ 72 73#define REG_N_SETS(N) (VARRAY_REG (reg_n_info, N)->sets) 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 81#define REG_N_DEATHS(N) (VARRAY_REG (reg_n_info, N)->deaths) 82 83/* Indexed by N; says whether a pseudo register N was ever used 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 87#define REG_CHANGES_SIZE(N) (VARRAY_REG (reg_n_info, N)->changes_size) 88 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. */ 105 106#define REG_N_CALLS_CROSSED(N) (VARRAY_REG (reg_n_info, N)->calls_crossed) 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 120 is not required. global.c makes an allocno for this but does 121 not try to assign a hard register to it. */ 122 123#define REG_LIVE_LENGTH(N) (VARRAY_REG (reg_n_info, N)->live_length) 124 125/* Vector of substitutions of register numbers, 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 130 in the machine dependent files access it. */ 131 132extern short *reg_renumber; 133 134/* Vector indexed by hardware reg 135 saying whether that reg is ever used. */ 136 137extern char regs_ever_live[FIRST_PSEUDO_REGISTER]; 138 139/* Vector indexed by hardware reg giving its name. */ 140 141extern char *reg_names[FIRST_PSEUDO_REGISTER]; 142 143/* 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 148extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER]; 149 150/* 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. */ 154 155#define REGNO_FIRST_UID(N) (VARRAY_REG (reg_n_info, N)->first_uid) 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. */ 162 163#define REGNO_LAST_UID(N) (VARRAY_REG (reg_n_info, N)->last_uid) 164 165/* Similar, but includes insns that mention the reg in their notes. */ 166 167#define REGNO_LAST_NOTE_UID(N) (VARRAY_REG (reg_n_info, N)->last_note_uid) 168 169/* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function. 170 After rtl generation, it is 1 plus the largest register number used. */ 171 172extern int reg_rtx_no; 173 174/* Vector indexed by regno; contains 1 for a register is considered a pointer. 175 Reloading, etc. will use a pointer register rather than a non-pointer 176 as the base register in an address, when there is a choice of two regs. */ 177 178extern char *regno_pointer_flag; 179#define REGNO_POINTER_FLAG(REGNO) regno_pointer_flag[REGNO] 180extern int regno_pointer_flag_length; 181 182/* List made of EXPR_LIST rtx's which gives pairs of pseudo registers 183 that have to go in the same hard reg. */ 184extern rtx regs_may_share; 185 186/* Vector mapping pseudo regno into the REG rtx for that register. 187 This is computed by reg_scan. */ 188 189extern rtx *regno_reg_rtx; 190 191/* Flag set by local-alloc or global-alloc if they decide to allocate 192 something in a call-clobbered register. */ 193 194extern int caller_save_needed; 195 196/* Predicate to decide whether to give a hard reg to a pseudo which 197 is referenced REFS times and would need to be saved and restored 198 around a call CALLS times. */ 199 200#ifndef CALLER_SAVE_PROFITABLE 201#define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS)) 202#endif 203 204/* On most machines a register class is likely to be spilled if it 205 only has one register. */ 206#ifndef CLASS_LIKELY_SPILLED_P 207#define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1) 208#endif 209 210/* Select a register mode required for caller save of hard regno REGNO. */ 211#ifndef HARD_REGNO_CALLER_SAVE_MODE 212#define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS) \ 213 choose_hard_reg_mode (REGNO, NREGS) 214#endif 215 216/* Registers that get partially clobbered by a call in a given mode. 217 These must not be call used registers. */ 218#ifndef HARD_REGNO_CALL_PART_CLOBBERED 219#define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0 220#endif 221 222/* Allocate reg_n_info tables */ 223extern void allocate_reg_info PROTO((size_t, int, int)); 224