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, 2004, 2005, 2006, 2007, 2008 Free Software 4 Foundation, Inc. 5 6This file is part of GCC. 7 8GCC is free software; you can redistribute it and/or modify it under 9the terms of the GNU General Public License as published by the Free 10Software Foundation; either version 3, or (at your option) any later 11version. 12 13GCC is distributed in the hope that it will be useful, but WITHOUT ANY 14WARRANTY; without even the implied warranty of MERCHANTABILITY or 15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16for more details. 17 18You should have received a copy of the GNU General Public License 19along with GCC; see the file COPYING3. If not see 20<http://www.gnu.org/licenses/>. */ 21 22#ifndef GCC_REGS_H 23#define GCC_REGS_H 24 25#include "varray.h" 26#include "obstack.h" 27#include "hard-reg-set.h" 28#include "basic-block.h" 29 30#define REG_BYTES(R) mode_size[(int) GET_MODE (R)] 31 32/* When you only have the mode of a pseudo register before it has a hard 33 register chosen for it, this reports the size of each hard register 34 a pseudo in such a mode would get allocated to. A target may 35 override this. */ 36 37#ifndef REGMODE_NATURAL_SIZE 38#define REGMODE_NATURAL_SIZE(MODE) UNITS_PER_WORD 39#endif 40 41#ifndef SMALL_REGISTER_CLASSES 42#define SMALL_REGISTER_CLASSES 0 43#endif 44 45/* Maximum register number used in this function, plus one. */ 46 47extern int max_regno; 48 49/* REG_N_REFS and REG_N_SETS are initialized by a call to 50 regstat_init_n_sets_and_refs from the current values of 51 DF_REG_DEF_COUNT and DF_REG_USE_COUNT. REG_N_REFS and REG_N_SETS 52 should only be used if a pass need to change these values in some 53 magical way or or the pass needs to have accurate values for these 54 and is not using incremental df scanning. 55 56 At the end of a pass that uses REG_N_REFS and REG_N_SETS, a call 57 should be made to regstat_free_n_sets_and_refs. 58 59 Local alloc seems to play pretty loose with these values. 60 REG_N_REFS is set to 0 if the register is used in an asm. 61 Furthermore, local_alloc calls regclass to hack both REG_N_REFS and 62 REG_N_SETS for three address insns. Other passes seem to have 63 other special values. */ 64 65 66 67/* Structure to hold values for REG_N_SETS (i) and REG_N_REFS (i). */ 68 69struct regstat_n_sets_and_refs_t 70{ 71 int sets; /* # of times (REG n) is set */ 72 int refs; /* # of times (REG n) is used or set */ 73}; 74 75extern struct regstat_n_sets_and_refs_t *regstat_n_sets_and_refs; 76 77/* Indexed by n, gives number of times (REG n) is used or set. */ 78static inline int 79REG_N_REFS(int regno) 80{ 81 return regstat_n_sets_and_refs[regno].refs; 82} 83 84/* Indexed by n, gives number of times (REG n) is used or set. */ 85#define SET_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs = V) 86#define INC_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs += V) 87 88/* Indexed by n, gives number of times (REG n) is set. */ 89static inline int 90REG_N_SETS (int regno) 91{ 92 return regstat_n_sets_and_refs[regno].sets; 93} 94 95/* Indexed by n, gives number of times (REG n) is set. */ 96#define SET_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets = V) 97#define INC_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets += V) 98 99 100/* Functions defined in reg-stat.c. */ 101extern void regstat_init_n_sets_and_refs (void); 102extern void regstat_free_n_sets_and_refs (void); 103extern void regstat_compute_ri (void); 104extern void regstat_free_ri (void); 105extern bitmap regstat_get_setjmp_crosses (void); 106extern void regstat_compute_calls_crossed (void); 107extern void regstat_free_calls_crossed (void); 108 109 110/* Register information indexed by register number. This structure is 111 initialized by calling regstat_compute_ri and is destroyed by 112 calling regstat_free_ri. */ 113struct reg_info_t 114{ 115 int freq; /* # estimated frequency (REG n) is used or set */ 116 int deaths; /* # of times (REG n) dies */ 117 int live_length; /* # of instructions (REG n) is live */ 118 int calls_crossed; /* # of calls (REG n) is live across */ 119 int freq_calls_crossed; /* # estimated frequency (REG n) crosses call */ 120 int throw_calls_crossed; /* # of calls that may throw (REG n) is live across */ 121 int basic_block; /* # of basic blocks (REG n) is used in */ 122}; 123 124extern struct reg_info_t *reg_info_p; 125 126/* The number allocated elements of reg_info_p. */ 127extern size_t reg_info_p_size; 128 129/* Estimate frequency of references to register N. */ 130 131#define REG_FREQ(N) (reg_info_p[N].freq) 132 133/* The weights for each insn varies from 0 to REG_FREQ_BASE. 134 This constant does not need to be high, as in infrequently executed 135 regions we want to count instructions equivalently to optimize for 136 size instead of speed. */ 137#define REG_FREQ_MAX 1000 138 139/* Compute register frequency from the BB frequency. When optimizing for size, 140 or profile driven feedback is available and the function is never executed, 141 frequency is always equivalent. Otherwise rescale the basic block 142 frequency. */ 143#define REG_FREQ_FROM_BB(bb) (optimize_size \ 144 || (flag_branch_probabilities \ 145 && !ENTRY_BLOCK_PTR->count) \ 146 ? REG_FREQ_MAX \ 147 : ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\ 148 ? ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\ 149 : 1) 150 151/* Indexed by N, gives number of insns in which register N dies. 152 Note that if register N is live around loops, it can die 153 in transitions between basic blocks, and that is not counted here. 154 So this is only a reliable indicator of how many regions of life there are 155 for registers that are contained in one basic block. */ 156 157#define REG_N_DEATHS(N) (reg_info_p[N].deaths) 158 159/* Get the number of consecutive words required to hold pseudo-reg N. */ 160 161#define PSEUDO_REGNO_SIZE(N) \ 162 ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1) \ 163 / UNITS_PER_WORD) 164 165/* Get the number of bytes required to hold pseudo-reg N. */ 166 167#define PSEUDO_REGNO_BYTES(N) \ 168 GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) 169 170/* Get the machine mode of pseudo-reg N. */ 171 172#define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N]) 173 174/* Indexed by N, gives number of CALL_INSNS across which (REG n) is live. */ 175 176#define REG_N_CALLS_CROSSED(N) (reg_info_p[N].calls_crossed) 177#define REG_FREQ_CALLS_CROSSED(N) (reg_info_p[N].freq_calls_crossed) 178 179/* Indexed by N, gives number of CALL_INSNS that may throw, across which 180 (REG n) is live. */ 181 182#define REG_N_THROWING_CALLS_CROSSED(N) (reg_info_p[N].throw_calls_crossed) 183 184/* Total number of instructions at which (REG n) is live. The larger 185 this is, the less priority (REG n) gets for allocation in a hard 186 register (in global-alloc). This is set in df-problems.c whenever 187 register info is requested and remains valid for the rest of the 188 compilation of the function; it is used to control register 189 allocation. 190 191 local-alloc.c may alter this number to change the priority. 192 193 Negative values are special. 194 -1 is used to mark a pseudo reg which has a constant or memory equivalent 195 and is used infrequently enough that it should not get a hard register. 196 -2 is used to mark a pseudo reg for a parameter, when a frame pointer 197 is not required. global.c makes an allocno for this but does 198 not try to assign a hard register to it. */ 199 200#define REG_LIVE_LENGTH(N) (reg_info_p[N].live_length) 201 202/* Indexed by n, gives number of basic block that (REG n) is used in. 203 If the value is REG_BLOCK_GLOBAL (-1), 204 it means (REG n) is used in more than one basic block. 205 REG_BLOCK_UNKNOWN (0) means it hasn't been seen yet so we don't know. 206 This information remains valid for the rest of the compilation 207 of the current function; it is used to control register allocation. */ 208 209#define REG_BLOCK_UNKNOWN 0 210#define REG_BLOCK_GLOBAL -1 211 212#define REG_BASIC_BLOCK(N) (reg_info_p[N].basic_block) 213 214/* Vector of substitutions of register numbers, 215 used to map pseudo regs into hardware regs. 216 217 This can't be folded into reg_n_info without changing all of the 218 machine dependent directories, since the reload functions 219 in the machine dependent files access it. */ 220 221extern short *reg_renumber; 222 223/* Vector indexed by machine mode saying whether there are regs of that mode. */ 224 225extern bool have_regs_of_mode [MAX_MACHINE_MODE]; 226 227/* For each hard register, the widest mode object that it can contain. 228 This will be a MODE_INT mode if the register can hold integers. Otherwise 229 it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the 230 register. */ 231 232extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER]; 233 234/* Flag set by local-alloc or global-alloc if they decide to allocate 235 something in a call-clobbered register. */ 236 237extern int caller_save_needed; 238 239/* Predicate to decide whether to give a hard reg to a pseudo which 240 is referenced REFS times and would need to be saved and restored 241 around a call CALLS times. */ 242 243#ifndef CALLER_SAVE_PROFITABLE 244#define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS)) 245#endif 246 247/* On most machines a register class is likely to be spilled if it 248 only has one register. */ 249#ifndef CLASS_LIKELY_SPILLED_P 250#define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1) 251#endif 252 253/* Select a register mode required for caller save of hard regno REGNO. */ 254#ifndef HARD_REGNO_CALLER_SAVE_MODE 255#define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \ 256 choose_hard_reg_mode (REGNO, NREGS, false) 257#endif 258 259/* Registers that get partially clobbered by a call in a given mode. 260 These must not be call used registers. */ 261#ifndef HARD_REGNO_CALL_PART_CLOBBERED 262#define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0 263#endif 264 265/* 1 if the corresponding class does contain register of given 266 mode. */ 267extern char contains_reg_of_mode [N_REG_CLASSES] [MAX_MACHINE_MODE]; 268 269typedef unsigned short move_table[N_REG_CLASSES]; 270 271/* Maximum cost of moving from a register in one class to a register 272 in another class. */ 273extern move_table *move_cost[MAX_MACHINE_MODE]; 274 275/* Specify number of hard registers given machine mode occupy. */ 276extern unsigned char hard_regno_nregs[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE]; 277 278/* Similar, but here we don't have to move if the first index is a 279 subset of the second so in that case the cost is zero. */ 280extern move_table *may_move_in_cost[MAX_MACHINE_MODE]; 281 282/* Similar, but here we don't have to move if the first index is a 283 superset of the second so in that case the cost is zero. */ 284extern move_table *may_move_out_cost[MAX_MACHINE_MODE]; 285 286/* Return an exclusive upper bound on the registers occupied by hard 287 register (reg:MODE REGNO). */ 288 289static inline unsigned int 290end_hard_regno (enum machine_mode mode, unsigned int regno) 291{ 292 return regno + hard_regno_nregs[regno][(int) mode]; 293} 294 295/* Likewise for hard register X. */ 296 297#define END_HARD_REGNO(X) end_hard_regno (GET_MODE (X), REGNO (X)) 298 299/* Likewise for hard or pseudo register X. */ 300 301#define END_REGNO(X) (HARD_REGISTER_P (X) ? END_HARD_REGNO (X) : REGNO (X) + 1) 302 303/* Add to REGS all the registers required to store a value of mode MODE 304 in register REGNO. */ 305 306static inline void 307add_to_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode, 308 unsigned int regno) 309{ 310 unsigned int end_regno; 311 312 end_regno = end_hard_regno (mode, regno); 313 do 314 SET_HARD_REG_BIT (*regs, regno); 315 while (++regno < end_regno); 316} 317 318/* Likewise, but remove the registers. */ 319 320static inline void 321remove_from_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode, 322 unsigned int regno) 323{ 324 unsigned int end_regno; 325 326 end_regno = end_hard_regno (mode, regno); 327 do 328 CLEAR_HARD_REG_BIT (*regs, regno); 329 while (++regno < end_regno); 330} 331 332/* Return true if REGS contains the whole of (reg:MODE REGNO). */ 333 334static inline bool 335in_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode, 336 unsigned int regno) 337{ 338 unsigned int end_regno; 339 340 if (!TEST_HARD_REG_BIT (regs, regno)) 341 return false; 342 343 end_regno = end_hard_regno (mode, regno); 344 while (++regno < end_regno) 345 if (!TEST_HARD_REG_BIT (regs, regno)) 346 return false; 347 348 return true; 349} 350 351/* Return true if (reg:MODE REGNO) includes an element of REGS. */ 352 353static inline bool 354overlaps_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode, 355 unsigned int regno) 356{ 357 unsigned int end_regno; 358 359 if (TEST_HARD_REG_BIT (regs, regno)) 360 return true; 361 362 end_regno = end_hard_regno (mode, regno); 363 while (++regno < end_regno) 364 if (TEST_HARD_REG_BIT (regs, regno)) 365 return true; 366 367 return false; 368} 369 370#endif /* GCC_REGS_H */ 371