| 1 | /* Define per-register tables for data flow info and register allocation. |
| 2 | Copyright (C) 1987, 1993, 1994, 1995, 1996, 1997, 1998, |
| 3 | 1999, 2000, 2003 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GCC. |
| 6 | |
| 7 | GCC is free software; you can redistribute it and/or modify it under |
| 8 | the terms of the GNU General Public License as published by the Free |
| 9 | Software Foundation; either version 2, or (at your option) any later |
| 10 | version. |
| 11 | |
| 12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| 13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 15 | for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with GCC; see the file COPYING. If not, write to the Free |
| 19 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA |
| 20 | 02111-1307, USA. */ |
| 21 | |
| 22 | |
| 23 | #include "varray.h" |
| 24 | #include "hard-reg-set.h" |
| 25 | #include "basic-block.h" |
| 26 | |
| 27 | #define REG_BYTES(R) mode_size[(int) GET_MODE (R)] |
| 28 | |
| 29 | /* When you only have the mode of a pseudo register before it has a hard |
| 30 | register chosen for it, this reports the size of each hard register |
| 31 | a pseudo in such a mode would get allocated to. A target may |
| 32 | override this. */ |
| 33 | |
| 34 | #ifndef REGMODE_NATURAL_SIZE |
| 35 | #define REGMODE_NATURAL_SIZE(MODE) UNITS_PER_WORD |
| 36 | #endif |
| 37 | |
| 38 | #ifndef SMALL_REGISTER_CLASSES |
| 39 | #define SMALL_REGISTER_CLASSES 0 |
| 40 | #endif |
| 41 | |
| 42 | /* Maximum register number used in this function, plus one. */ |
| 43 | |
| 44 | extern int max_regno; |
| 45 | |
| 46 | /* Register information indexed by register number */ |
| 47 | typedef struct reg_info_def |
| 48 | { /* fields set by reg_scan */ |
| 49 | int first_uid; /* UID of first insn to use (REG n) */ |
| 50 | int last_uid; /* UID of last insn to use (REG n) */ |
| 51 | int last_note_uid; /* UID of last note to use (REG n) */ |
| 52 | |
| 53 | /* fields set by reg_scan & flow_analysis */ |
| 54 | int sets; /* # of times (REG n) is set */ |
| 55 | |
| 56 | /* fields set by flow_analysis */ |
| 57 | int refs; /* # of times (REG n) is used or set */ |
| 58 | int freq; /* # estimated frequency (REG n) is used or set */ |
| 59 | int deaths; /* # of times (REG n) dies */ |
| 60 | int live_length; /* # of instructions (REG n) is live */ |
| 61 | int calls_crossed; /* # of calls (REG n) is live across */ |
| 62 | int throw_calls_crossed; /* # of calls that may throw (REG n) is live across */ |
| 63 | int basic_block; /* # of basic blocks (REG n) is used in */ |
| 64 | char changes_mode; /* whether (SUBREG (REG n)) exists and |
| 65 | is illegal. */ |
| 66 | } reg_info; |
| 67 | |
| 68 | extern varray_type reg_n_info; |
| 69 | |
| 70 | /* Indexed by n, gives number of times (REG n) is used or set. */ |
| 71 | |
| 72 | #define REG_N_REFS(N) (VARRAY_REG (reg_n_info, N)->refs) |
| 73 | |
| 74 | /* Estimate frequency of references to register N. */ |
| 75 | |
| 76 | #define REG_FREQ(N) (VARRAY_REG (reg_n_info, N)->freq) |
| 77 | |
| 78 | /* The weights for each insn varries from 0 to REG_FREQ_BASE. |
| 79 | This constant does not need to be high, as in infrequently executed |
| 80 | regions we want to count instructions equivalently to optimize for |
| 81 | size instead of speed. */ |
| 82 | #define REG_FREQ_MAX 1000 |
| 83 | |
| 84 | /* Compute register frequency from the BB frequency. When optimizing for size, |
| 85 | or profile driven feedback is available and the function is never executed, |
| 86 | frequency is always equivalent. Otherwise rescale the basic block |
| 87 | frequency. */ |
| 88 | #define REG_FREQ_FROM_BB(bb) (optimize_size \ |
| 89 | || (flag_branch_probabilities \ |
| 90 | && !ENTRY_BLOCK_PTR->count) \ |
| 91 | ? REG_FREQ_MAX \ |
| 92 | : ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\ |
| 93 | ? ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\ |
| 94 | : 1) |
| 95 | |
| 96 | /* Indexed by n, gives number of times (REG n) is set. |
| 97 | ??? both regscan and flow allocate space for this. We should settle |
| 98 | on just copy. */ |
| 99 | |
| 100 | #define REG_N_SETS(N) (VARRAY_REG (reg_n_info, N)->sets) |
| 101 | |
| 102 | /* Indexed by N, gives number of insns in which register N dies. |
| 103 | Note that if register N is live around loops, it can die |
| 104 | in transitions between basic blocks, and that is not counted here. |
| 105 | So this is only a reliable indicator of how many regions of life there are |
| 106 | for registers that are contained in one basic block. */ |
| 107 | |
| 108 | #define REG_N_DEATHS(N) (VARRAY_REG (reg_n_info, N)->deaths) |
| 109 | |
| 110 | /* Get the number of consecutive words required to hold pseudo-reg N. */ |
| 111 | |
| 112 | #define PSEUDO_REGNO_SIZE(N) \ |
| 113 | ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1) \ |
| 114 | / UNITS_PER_WORD) |
| 115 | |
| 116 | /* Get the number of bytes required to hold pseudo-reg N. */ |
| 117 | |
| 118 | #define PSEUDO_REGNO_BYTES(N) \ |
| 119 | GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) |
| 120 | |
| 121 | /* Get the machine mode of pseudo-reg N. */ |
| 122 | |
| 123 | #define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N]) |
| 124 | |
| 125 | /* Indexed by N, gives number of CALL_INSNS across which (REG n) is live. */ |
| 126 | |
| 127 | #define REG_N_CALLS_CROSSED(N) (VARRAY_REG (reg_n_info, N)->calls_crossed) |
| 128 | |
| 129 | /* Indexed by N, gives number of CALL_INSNS that may throw, across which |
| 130 | (REG n) is live. */ |
| 131 | |
| 132 | #define REG_N_THROWING_CALLS_CROSSED(N) \ |
| 133 | (VARRAY_REG (reg_n_info, N)->throw_calls_crossed) |
| 134 | |
| 135 | /* Total number of instructions at which (REG n) is live. |
| 136 | The larger this is, the less priority (REG n) gets for |
| 137 | allocation in a hard register (in global-alloc). |
| 138 | This is set in flow.c and remains valid for the rest of the compilation |
| 139 | of the function; it is used to control register allocation. |
| 140 | |
| 141 | local-alloc.c may alter this number to change the priority. |
| 142 | |
| 143 | Negative values are special. |
| 144 | -1 is used to mark a pseudo reg which has a constant or memory equivalent |
| 145 | and is used infrequently enough that it should not get a hard register. |
| 146 | -2 is used to mark a pseudo reg for a parameter, when a frame pointer |
| 147 | is not required. global.c makes an allocno for this but does |
| 148 | not try to assign a hard register to it. */ |
| 149 | |
| 150 | #define REG_LIVE_LENGTH(N) (VARRAY_REG (reg_n_info, N)->live_length) |
| 151 | |
| 152 | /* Vector of substitutions of register numbers, |
| 153 | used to map pseudo regs into hardware regs. |
| 154 | |
| 155 | This can't be folded into reg_n_info without changing all of the |
| 156 | machine dependent directories, since the reload functions |
| 157 | in the machine dependent files access it. */ |
| 158 | |
| 159 | extern short *reg_renumber; |
| 160 | |
| 161 | /* Vector indexed by hardware reg saying whether that reg is ever used. */ |
| 162 | |
| 163 | extern char regs_ever_live[FIRST_PSEUDO_REGISTER]; |
| 164 | |
| 165 | /* Like regs_ever_live, but saying whether reg is set by asm statements. */ |
| 166 | |
| 167 | extern char regs_asm_clobbered[FIRST_PSEUDO_REGISTER]; |
| 168 | |
| 169 | /* For each hard register, the widest mode object that it can contain. |
| 170 | This will be a MODE_INT mode if the register can hold integers. Otherwise |
| 171 | it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the |
| 172 | register. */ |
| 173 | |
| 174 | extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER]; |
| 175 | |
| 176 | /* Vector indexed by regno; gives uid of first insn using that reg. |
| 177 | This is computed by reg_scan for use by cse and loop. |
| 178 | It is sometimes adjusted for subsequent changes during loop, |
| 179 | but not adjusted by cse even if cse invalidates it. */ |
| 180 | |
| 181 | #define REGNO_FIRST_UID(N) (VARRAY_REG (reg_n_info, N)->first_uid) |
| 182 | |
| 183 | /* Vector indexed by regno; gives uid of last insn using that reg. |
| 184 | This is computed by reg_scan for use by cse and loop. |
| 185 | It is sometimes adjusted for subsequent changes during loop, |
| 186 | but not adjusted by cse even if cse invalidates it. |
| 187 | This is harmless since cse won't scan through a loop end. */ |
| 188 | |
| 189 | #define REGNO_LAST_UID(N) (VARRAY_REG (reg_n_info, N)->last_uid) |
| 190 | |
| 191 | /* Similar, but includes insns that mention the reg in their notes. */ |
| 192 | |
| 193 | #define REGNO_LAST_NOTE_UID(N) (VARRAY_REG (reg_n_info, N)->last_note_uid) |
| 194 | |
| 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 | /* Flag set by local-alloc or global-alloc if they decide to allocate |
| 200 | something in a call-clobbered register. */ |
| 201 | |
| 202 | extern int caller_save_needed; |
| 203 | |
| 204 | /* Predicate to decide whether to give a hard reg to a pseudo which |
| 205 | is referenced REFS times and would need to be saved and restored |
| 206 | around a call CALLS times. */ |
| 207 | |
| 208 | #ifndef CALLER_SAVE_PROFITABLE |
| 209 | #define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS)) |
| 210 | #endif |
| 211 | |
| 212 | /* On most machines a register class is likely to be spilled if it |
| 213 | only has one register. */ |
| 214 | #ifndef CLASS_LIKELY_SPILLED_P |
| 215 | #define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1) |
| 216 | #endif |
| 217 | |
| 218 | /* Select a register mode required for caller save of hard regno REGNO. */ |
| 219 | #ifndef HARD_REGNO_CALLER_SAVE_MODE |
| 220 | #define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \ |
| 221 | choose_hard_reg_mode (REGNO, NREGS, false) |
| 222 | #endif |
| 223 | |
| 224 | /* Registers that get partially clobbered by a call in a given mode. |
| 225 | These must not be call used registers. */ |
| 226 | #ifndef HARD_REGNO_CALL_PART_CLOBBERED |
| 227 | #define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0 |
| 228 | #endif |
| 229 | |
| 230 | /* Allocate reg_n_info tables */ |
| 231 | extern void allocate_reg_info (size_t, int, int); |