| 1 | /* |
| 2 | * Copyright (C) 2014-2020 Paul Cercueil <paul@crapouillou.net> |
| 3 | * |
| 4 | * This library is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU Lesser General Public |
| 6 | * License as published by the Free Software Foundation; either |
| 7 | * version 2.1 of the License, or (at your option) any later version. |
| 8 | * |
| 9 | * This library is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | * Lesser General Public License for more details. |
| 13 | */ |
| 14 | |
| 15 | #include "debug.h" |
| 16 | #include "memmanager.h" |
| 17 | #include "regcache.h" |
| 18 | |
| 19 | #include <lightning.h> |
| 20 | #include <stdbool.h> |
| 21 | #include <stddef.h> |
| 22 | |
| 23 | struct native_register { |
| 24 | bool used, loaded, dirty, output, extend, extended, locked; |
| 25 | s8 emulated_register; |
| 26 | }; |
| 27 | |
| 28 | struct regcache { |
| 29 | struct lightrec_state *state; |
| 30 | struct native_register lightrec_regs[NUM_REGS + NUM_TEMPS]; |
| 31 | }; |
| 32 | |
| 33 | static const char * mips_regs[] = { |
| 34 | "zero", |
| 35 | "at", |
| 36 | "v0", "v1", |
| 37 | "a0", "a1", "a2", "a3", |
| 38 | "t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", |
| 39 | "s0", "s1", "s2", "s3", "s4", "s5", "s6", "s7", |
| 40 | "t8", "t9", |
| 41 | "k0", "k1", |
| 42 | "gp", "sp", "fp", "ra", |
| 43 | "lo", "hi", |
| 44 | }; |
| 45 | |
| 46 | const char * lightrec_reg_name(u8 reg) |
| 47 | { |
| 48 | return mips_regs[reg]; |
| 49 | } |
| 50 | |
| 51 | static inline u8 lightrec_reg_number(const struct regcache *cache, |
| 52 | const struct native_register *nreg) |
| 53 | { |
| 54 | return (u8) (((uintptr_t) nreg - (uintptr_t) cache->lightrec_regs) |
| 55 | / sizeof(*nreg)); |
| 56 | } |
| 57 | |
| 58 | static inline u8 lightrec_reg_to_lightning(const struct regcache *cache, |
| 59 | const struct native_register *nreg) |
| 60 | { |
| 61 | u8 offset = lightrec_reg_number(cache, nreg); |
| 62 | return offset < NUM_REGS ? JIT_V(offset) : JIT_R(offset - NUM_REGS); |
| 63 | } |
| 64 | |
| 65 | static inline struct native_register * lightning_reg_to_lightrec( |
| 66 | struct regcache *cache, u8 reg) |
| 67 | { |
| 68 | if ((JIT_V0 > JIT_R0 && reg >= JIT_V0) || |
| 69 | (JIT_V0 < JIT_R0 && reg < JIT_R0)) { |
| 70 | if (JIT_V1 > JIT_V0) |
| 71 | return &cache->lightrec_regs[reg - JIT_V0]; |
| 72 | else |
| 73 | return &cache->lightrec_regs[JIT_V0 - reg]; |
| 74 | } else { |
| 75 | if (JIT_R1 > JIT_R0) |
| 76 | return &cache->lightrec_regs[NUM_REGS + reg - JIT_R0]; |
| 77 | else |
| 78 | return &cache->lightrec_regs[NUM_REGS + JIT_R0 - reg]; |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | static struct native_register * alloc_temp(struct regcache *cache) |
| 83 | { |
| 84 | unsigned int i; |
| 85 | |
| 86 | /* We search the register list in reverse order. As temporaries are |
| 87 | * meant to be used only in the emitter functions, they can be mapped to |
| 88 | * caller-saved registers, as they won't have to be saved back to |
| 89 | * memory. */ |
| 90 | for (i = ARRAY_SIZE(cache->lightrec_regs); i; i--) { |
| 91 | struct native_register *nreg = &cache->lightrec_regs[i - 1]; |
| 92 | if (!nreg->used && !nreg->loaded && !nreg->dirty) |
| 93 | return nreg; |
| 94 | } |
| 95 | |
| 96 | for (i = ARRAY_SIZE(cache->lightrec_regs); i; i--) { |
| 97 | struct native_register *nreg = &cache->lightrec_regs[i - 1]; |
| 98 | if (!nreg->used) |
| 99 | return nreg; |
| 100 | } |
| 101 | |
| 102 | return NULL; |
| 103 | } |
| 104 | |
| 105 | static struct native_register * find_mapped_reg(struct regcache *cache, |
| 106 | u8 reg, bool out) |
| 107 | { |
| 108 | unsigned int i; |
| 109 | |
| 110 | for (i = 0; i < ARRAY_SIZE(cache->lightrec_regs); i++) { |
| 111 | struct native_register *nreg = &cache->lightrec_regs[i]; |
| 112 | if ((!reg || nreg->loaded || nreg->dirty) && |
| 113 | nreg->emulated_register == reg && |
| 114 | (!out || !nreg->locked)) |
| 115 | return nreg; |
| 116 | } |
| 117 | |
| 118 | return NULL; |
| 119 | } |
| 120 | |
| 121 | static struct native_register * alloc_in_out(struct regcache *cache, |
| 122 | u8 reg, bool out) |
| 123 | { |
| 124 | struct native_register *nreg; |
| 125 | unsigned int i; |
| 126 | |
| 127 | /* Try to find if the register is already mapped somewhere */ |
| 128 | nreg = find_mapped_reg(cache, reg, out); |
| 129 | if (nreg) |
| 130 | return nreg; |
| 131 | |
| 132 | /* Try to allocate a non-dirty, non-loaded register. |
| 133 | * Loaded registers may be re-used later, so it's better to avoid |
| 134 | * re-using one if possible. */ |
| 135 | for (i = 0; i < ARRAY_SIZE(cache->lightrec_regs); i++) { |
| 136 | nreg = &cache->lightrec_regs[i]; |
| 137 | if (!nreg->used && !nreg->dirty && !nreg->loaded) |
| 138 | return nreg; |
| 139 | } |
| 140 | |
| 141 | /* Try to allocate a non-dirty register */ |
| 142 | for (i = 0; i < ARRAY_SIZE(cache->lightrec_regs); i++) { |
| 143 | nreg = &cache->lightrec_regs[i]; |
| 144 | if (!nreg->used && !nreg->dirty) |
| 145 | return nreg; |
| 146 | } |
| 147 | |
| 148 | for (i = 0; i < ARRAY_SIZE(cache->lightrec_regs); i++) { |
| 149 | nreg = &cache->lightrec_regs[i]; |
| 150 | if (!nreg->used) |
| 151 | return nreg; |
| 152 | } |
| 153 | |
| 154 | return NULL; |
| 155 | } |
| 156 | |
| 157 | static void lightrec_discard_nreg(struct native_register *nreg) |
| 158 | { |
| 159 | nreg->extended = false; |
| 160 | nreg->loaded = false; |
| 161 | nreg->output = false; |
| 162 | nreg->dirty = false; |
| 163 | nreg->used = false; |
| 164 | nreg->locked = false; |
| 165 | nreg->emulated_register = -1; |
| 166 | } |
| 167 | |
| 168 | static void lightrec_unload_nreg(struct regcache *cache, jit_state_t *_jit, |
| 169 | struct native_register *nreg, u8 jit_reg) |
| 170 | { |
| 171 | /* If we get a dirty register, store back the old value */ |
| 172 | if (nreg->dirty) { |
| 173 | s16 offset = offsetof(struct lightrec_state, native_reg_cache) |
| 174 | + (nreg->emulated_register << 2); |
| 175 | |
| 176 | jit_stxi_i(offset, LIGHTREC_REG_STATE, jit_reg); |
| 177 | } |
| 178 | |
| 179 | lightrec_discard_nreg(nreg); |
| 180 | } |
| 181 | |
| 182 | void lightrec_unload_reg(struct regcache *cache, jit_state_t *_jit, u8 jit_reg) |
| 183 | { |
| 184 | lightrec_unload_nreg(cache, _jit, |
| 185 | lightning_reg_to_lightrec(cache, jit_reg), jit_reg); |
| 186 | } |
| 187 | |
| 188 | /* lightrec_lock_reg: the register will be cleaned if dirty, then locked. |
| 189 | * A locked register cannot only be used as input, not output. */ |
| 190 | void lightrec_lock_reg(struct regcache *cache, jit_state_t *_jit, u8 jit_reg) |
| 191 | { |
| 192 | struct native_register *reg = lightning_reg_to_lightrec(cache, jit_reg); |
| 193 | |
| 194 | lightrec_clean_reg(cache, _jit, jit_reg); |
| 195 | |
| 196 | reg->locked = true; |
| 197 | } |
| 198 | |
| 199 | u8 lightrec_alloc_reg(struct regcache *cache, jit_state_t *_jit, u8 jit_reg) |
| 200 | { |
| 201 | struct native_register *reg = lightning_reg_to_lightrec(cache, jit_reg); |
| 202 | |
| 203 | lightrec_unload_nreg(cache, _jit, reg, jit_reg); |
| 204 | |
| 205 | reg->used = true; |
| 206 | return jit_reg; |
| 207 | } |
| 208 | |
| 209 | u8 lightrec_alloc_reg_temp(struct regcache *cache, jit_state_t *_jit) |
| 210 | { |
| 211 | u8 jit_reg; |
| 212 | struct native_register *nreg = alloc_temp(cache); |
| 213 | if (!nreg) { |
| 214 | /* No free register, no dirty register to free. */ |
| 215 | pr_err("No more registers! Abandon ship!\n"); |
| 216 | return 0; |
| 217 | } |
| 218 | |
| 219 | jit_reg = lightrec_reg_to_lightning(cache, nreg); |
| 220 | lightrec_unload_nreg(cache, _jit, nreg, jit_reg); |
| 221 | |
| 222 | nreg->used = true; |
| 223 | return jit_reg; |
| 224 | } |
| 225 | |
| 226 | u8 lightrec_alloc_reg_out(struct regcache *cache, jit_state_t *_jit, u8 reg) |
| 227 | { |
| 228 | u8 jit_reg; |
| 229 | struct native_register *nreg = alloc_in_out(cache, reg, true); |
| 230 | if (!nreg) { |
| 231 | /* No free register, no dirty register to free. */ |
| 232 | pr_err("No more registers! Abandon ship!\n"); |
| 233 | return 0; |
| 234 | } |
| 235 | |
| 236 | jit_reg = lightrec_reg_to_lightning(cache, nreg); |
| 237 | |
| 238 | /* If we get a dirty register that doesn't correspond to the one |
| 239 | * we're requesting, store back the old value */ |
| 240 | if (nreg->emulated_register != reg) |
| 241 | lightrec_unload_nreg(cache, _jit, nreg, jit_reg); |
| 242 | |
| 243 | nreg->extend = false; |
| 244 | nreg->used = true; |
| 245 | nreg->output = true; |
| 246 | nreg->emulated_register = reg; |
| 247 | return jit_reg; |
| 248 | } |
| 249 | |
| 250 | u8 lightrec_alloc_reg_in(struct regcache *cache, jit_state_t *_jit, u8 reg) |
| 251 | { |
| 252 | u8 jit_reg; |
| 253 | bool reg_changed; |
| 254 | struct native_register *nreg = alloc_in_out(cache, reg, false); |
| 255 | if (!nreg) { |
| 256 | /* No free register, no dirty register to free. */ |
| 257 | pr_err("No more registers! Abandon ship!\n"); |
| 258 | return 0; |
| 259 | } |
| 260 | |
| 261 | jit_reg = lightrec_reg_to_lightning(cache, nreg); |
| 262 | |
| 263 | /* If we get a dirty register that doesn't correspond to the one |
| 264 | * we're requesting, store back the old value */ |
| 265 | reg_changed = nreg->emulated_register != reg; |
| 266 | if (reg_changed) |
| 267 | lightrec_unload_nreg(cache, _jit, nreg, jit_reg); |
| 268 | |
| 269 | if (!nreg->loaded && !nreg->dirty && reg != 0) { |
| 270 | s16 offset = offsetof(struct lightrec_state, native_reg_cache) |
| 271 | + (reg << 2); |
| 272 | |
| 273 | /* Load previous value from register cache */ |
| 274 | jit_ldxi_i(jit_reg, LIGHTREC_REG_STATE, offset); |
| 275 | nreg->loaded = true; |
| 276 | nreg->extended = true; |
| 277 | } |
| 278 | |
| 279 | /* Clear register r0 before use */ |
| 280 | if (reg == 0 && (!nreg->loaded || nreg->dirty)) { |
| 281 | jit_movi(jit_reg, 0); |
| 282 | nreg->extended = true; |
| 283 | nreg->loaded = true; |
| 284 | } |
| 285 | |
| 286 | nreg->used = true; |
| 287 | nreg->output = false; |
| 288 | nreg->emulated_register = reg; |
| 289 | return jit_reg; |
| 290 | } |
| 291 | |
| 292 | u8 lightrec_alloc_reg_out_ext(struct regcache *cache, jit_state_t *_jit, u8 reg) |
| 293 | { |
| 294 | struct native_register *nreg; |
| 295 | u8 jit_reg; |
| 296 | |
| 297 | jit_reg = lightrec_alloc_reg_out(cache, _jit, reg); |
| 298 | nreg = lightning_reg_to_lightrec(cache, jit_reg); |
| 299 | |
| 300 | nreg->extend = true; |
| 301 | |
| 302 | return jit_reg; |
| 303 | } |
| 304 | |
| 305 | u8 lightrec_alloc_reg_in_ext(struct regcache *cache, jit_state_t *_jit, u8 reg) |
| 306 | { |
| 307 | struct native_register *nreg; |
| 308 | u8 jit_reg; |
| 309 | |
| 310 | jit_reg = lightrec_alloc_reg_in(cache, _jit, reg); |
| 311 | nreg = lightning_reg_to_lightrec(cache, jit_reg); |
| 312 | |
| 313 | #if __WORDSIZE == 64 |
| 314 | if (!nreg->extended) { |
| 315 | nreg->extended = true; |
| 316 | jit_extr_i(jit_reg, jit_reg); |
| 317 | } |
| 318 | #endif |
| 319 | |
| 320 | return jit_reg; |
| 321 | } |
| 322 | |
| 323 | u8 lightrec_request_reg_in(struct regcache *cache, jit_state_t *_jit, |
| 324 | u8 reg, u8 jit_reg) |
| 325 | { |
| 326 | struct native_register *nreg; |
| 327 | u16 offset; |
| 328 | |
| 329 | nreg = find_mapped_reg(cache, reg, false); |
| 330 | if (nreg) { |
| 331 | jit_reg = lightrec_reg_to_lightning(cache, nreg); |
| 332 | nreg->used = true; |
| 333 | return jit_reg; |
| 334 | } |
| 335 | |
| 336 | nreg = lightning_reg_to_lightrec(cache, jit_reg); |
| 337 | lightrec_unload_nreg(cache, _jit, nreg, jit_reg); |
| 338 | |
| 339 | /* Load previous value from register cache */ |
| 340 | offset = offsetof(struct lightrec_state, native_reg_cache) + (reg << 2); |
| 341 | jit_ldxi_i(jit_reg, LIGHTREC_REG_STATE, offset); |
| 342 | |
| 343 | nreg->extended = true; |
| 344 | nreg->used = true; |
| 345 | nreg->loaded = true; |
| 346 | nreg->emulated_register = reg; |
| 347 | |
| 348 | return jit_reg; |
| 349 | } |
| 350 | |
| 351 | static void free_reg(struct native_register *nreg) |
| 352 | { |
| 353 | /* Set output registers as dirty */ |
| 354 | if (nreg->used && nreg->output && nreg->emulated_register > 0) |
| 355 | nreg->dirty = true; |
| 356 | if (nreg->output) |
| 357 | nreg->extended = nreg->extend; |
| 358 | nreg->used = false; |
| 359 | } |
| 360 | |
| 361 | void lightrec_free_reg(struct regcache *cache, u8 jit_reg) |
| 362 | { |
| 363 | free_reg(lightning_reg_to_lightrec(cache, jit_reg)); |
| 364 | } |
| 365 | |
| 366 | void lightrec_free_regs(struct regcache *cache) |
| 367 | { |
| 368 | unsigned int i; |
| 369 | |
| 370 | for (i = 0; i < ARRAY_SIZE(cache->lightrec_regs); i++) |
| 371 | free_reg(&cache->lightrec_regs[i]); |
| 372 | } |
| 373 | |
| 374 | static void clean_reg(jit_state_t *_jit, |
| 375 | struct native_register *nreg, u8 jit_reg, bool clean) |
| 376 | { |
| 377 | if (nreg->dirty) { |
| 378 | s16 offset = offsetof(struct lightrec_state, native_reg_cache) |
| 379 | + (nreg->emulated_register << 2); |
| 380 | |
| 381 | jit_stxi_i(offset, LIGHTREC_REG_STATE, jit_reg); |
| 382 | nreg->loaded |= nreg->dirty; |
| 383 | nreg->dirty ^= clean; |
| 384 | } |
| 385 | } |
| 386 | |
| 387 | static void clean_regs(struct regcache *cache, jit_state_t *_jit, bool clean) |
| 388 | { |
| 389 | unsigned int i; |
| 390 | |
| 391 | for (i = 0; i < NUM_REGS; i++) |
| 392 | clean_reg(_jit, &cache->lightrec_regs[i], JIT_V(i), clean); |
| 393 | for (i = 0; i < NUM_TEMPS; i++) { |
| 394 | clean_reg(_jit, &cache->lightrec_regs[i + NUM_REGS], |
| 395 | JIT_R(i), clean); |
| 396 | } |
| 397 | } |
| 398 | |
| 399 | void lightrec_storeback_regs(struct regcache *cache, jit_state_t *_jit) |
| 400 | { |
| 401 | clean_regs(cache, _jit, false); |
| 402 | } |
| 403 | |
| 404 | void lightrec_clean_regs(struct regcache *cache, jit_state_t *_jit) |
| 405 | { |
| 406 | clean_regs(cache, _jit, true); |
| 407 | } |
| 408 | |
| 409 | void lightrec_clean_reg(struct regcache *cache, jit_state_t *_jit, u8 jit_reg) |
| 410 | { |
| 411 | struct native_register *reg = lightning_reg_to_lightrec(cache, jit_reg); |
| 412 | clean_reg(_jit, reg, jit_reg, true); |
| 413 | } |
| 414 | |
| 415 | void lightrec_clean_reg_if_loaded(struct regcache *cache, jit_state_t *_jit, |
| 416 | u8 reg, bool unload) |
| 417 | { |
| 418 | struct native_register *nreg; |
| 419 | u8 jit_reg; |
| 420 | |
| 421 | nreg = find_mapped_reg(cache, reg, false); |
| 422 | if (nreg) { |
| 423 | jit_reg = lightrec_reg_to_lightning(cache, nreg); |
| 424 | |
| 425 | if (unload) |
| 426 | lightrec_unload_nreg(cache, _jit, nreg, jit_reg); |
| 427 | else |
| 428 | clean_reg(_jit, nreg, jit_reg, true); |
| 429 | } |
| 430 | } |
| 431 | |
| 432 | struct native_register * lightrec_regcache_enter_branch(struct regcache *cache) |
| 433 | { |
| 434 | struct native_register *backup; |
| 435 | |
| 436 | backup = lightrec_malloc(cache->state, MEM_FOR_LIGHTREC, |
| 437 | sizeof(cache->lightrec_regs)); |
| 438 | memcpy(backup, &cache->lightrec_regs, sizeof(cache->lightrec_regs)); |
| 439 | |
| 440 | return backup; |
| 441 | } |
| 442 | |
| 443 | void lightrec_regcache_leave_branch(struct regcache *cache, |
| 444 | struct native_register *regs) |
| 445 | { |
| 446 | memcpy(&cache->lightrec_regs, regs, sizeof(cache->lightrec_regs)); |
| 447 | lightrec_free(cache->state, MEM_FOR_LIGHTREC, |
| 448 | sizeof(cache->lightrec_regs), regs); |
| 449 | } |
| 450 | |
| 451 | void lightrec_regcache_reset(struct regcache *cache) |
| 452 | { |
| 453 | memset(&cache->lightrec_regs, 0, sizeof(cache->lightrec_regs)); |
| 454 | } |
| 455 | |
| 456 | struct regcache * lightrec_regcache_init(struct lightrec_state *state) |
| 457 | { |
| 458 | struct regcache *cache; |
| 459 | |
| 460 | cache = lightrec_calloc(state, MEM_FOR_LIGHTREC, sizeof(*cache)); |
| 461 | if (!cache) |
| 462 | return NULL; |
| 463 | |
| 464 | cache->state = state; |
| 465 | |
| 466 | return cache; |
| 467 | } |
| 468 | |
| 469 | void lightrec_free_regcache(struct regcache *cache) |
| 470 | { |
| 471 | return lightrec_free(cache->state, MEM_FOR_LIGHTREC, |
| 472 | sizeof(*cache), cache); |
| 473 | } |
| 474 | |
| 475 | void lightrec_regcache_mark_live(struct regcache *cache, jit_state_t *_jit) |
| 476 | { |
| 477 | struct native_register *nreg; |
| 478 | unsigned int i; |
| 479 | |
| 480 | #ifdef _WIN32 |
| 481 | /* FIXME: GNU Lightning on Windows seems to use our mapped registers as |
| 482 | * temporaries. Until the actual bug is found and fixed, unconditionally |
| 483 | * mark our registers as live here. */ |
| 484 | for (i = 0; i < NUM_REGS; i++) { |
| 485 | nreg = &cache->lightrec_regs[i]; |
| 486 | |
| 487 | if (nreg->used || nreg->loaded || nreg->dirty) |
| 488 | jit_live(JIT_V(i)); |
| 489 | } |
| 490 | #endif |
| 491 | |
| 492 | for (i = 0; i < NUM_TEMPS; i++) { |
| 493 | nreg = &cache->lightrec_regs[NUM_REGS + i]; |
| 494 | |
| 495 | if (nreg->used || nreg->loaded || nreg->dirty) |
| 496 | jit_live(JIT_R(i)); |
| 497 | } |
| 498 | } |