1 2 /*---------------------------------------------------------------*/ 3 /*--- begin guest_arm_helpers.c ---*/ 4 /*---------------------------------------------------------------*/ 5 6 /* 7 This file is part of Valgrind, a dynamic binary instrumentation 8 framework. 9 10 Copyright (C) 2004-2013 OpenWorks LLP 11 info (at) open-works.net 12 13 This program is free software; you can redistribute it and/or 14 modify it under the terms of the GNU General Public License as 15 published by the Free Software Foundation; either version 2 of the 16 License, or (at your option) any later version. 17 18 This program is distributed in the hope that it will be useful, but 19 WITHOUT ANY WARRANTY; without even the implied warranty of 20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 21 General Public License for more details. 22 23 You should have received a copy of the GNU General Public License 24 along with this program; if not, write to the Free Software 25 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 26 02110-1301, USA. 27 28 The GNU General Public License is contained in the file COPYING. 29 */ 30 31 #include "libvex_basictypes.h" 32 #include "libvex_emnote.h" 33 #include "libvex_guest_arm.h" 34 #include "libvex_ir.h" 35 #include "libvex.h" 36 37 #include "main_util.h" 38 #include "main_globals.h" 39 #include "guest_generic_bb_to_IR.h" 40 #include "guest_arm_defs.h" 41 42 43 /* This file contains helper functions for arm guest code. Calls to 44 these functions are generated by the back end. These calls are of 45 course in the host machine code and this file will be compiled to 46 host machine code, so that all makes sense. 47 48 Only change the signatures of these helper functions very 49 carefully. If you change the signature here, you'll have to change 50 the parameters passed to it in the IR calls constructed by 51 guest-arm/toIR.c. 52 */ 53 54 55 /* Set to 1 to get detailed profiling info about individual N, Z, C 56 and V flag evaluation. */ 57 #define PROFILE_NZCV_FLAGS 0 58 59 #if PROFILE_NZCV_FLAGS 60 61 static UInt tab_n_eval[ARMG_CC_OP_NUMBER]; 62 static UInt tab_z_eval[ARMG_CC_OP_NUMBER]; 63 static UInt tab_c_eval[ARMG_CC_OP_NUMBER]; 64 static UInt tab_v_eval[ARMG_CC_OP_NUMBER]; 65 static UInt initted = 0; 66 static UInt tot_evals = 0; 67 68 static void initCounts ( void ) 69 { 70 UInt i; 71 for (i = 0; i < ARMG_CC_OP_NUMBER; i++) { 72 tab_n_eval[i] = tab_z_eval[i] = tab_c_eval[i] = tab_v_eval[i] = 0; 73 } 74 initted = 1; 75 } 76 77 static void showCounts ( void ) 78 { 79 UInt i; 80 vex_printf("\n N Z C V\n"); 81 vex_printf( "---------------------------------------------------\n"); 82 for (i = 0; i < ARMG_CC_OP_NUMBER; i++) { 83 vex_printf("CC_OP=%d %9d %9d %9d %9d\n", 84 i, 85 tab_n_eval[i], tab_z_eval[i], 86 tab_c_eval[i], tab_v_eval[i] ); 87 } 88 } 89 90 #define NOTE_N_EVAL(_cc_op) NOTE_EVAL(_cc_op, tab_n_eval) 91 #define NOTE_Z_EVAL(_cc_op) NOTE_EVAL(_cc_op, tab_z_eval) 92 #define NOTE_C_EVAL(_cc_op) NOTE_EVAL(_cc_op, tab_c_eval) 93 #define NOTE_V_EVAL(_cc_op) NOTE_EVAL(_cc_op, tab_v_eval) 94 95 #define NOTE_EVAL(_cc_op, _tab) \ 96 do { \ 97 if (!initted) initCounts(); \ 98 vassert( ((UInt)(_cc_op)) < ARMG_CC_OP_NUMBER); \ 99 _tab[(UInt)(_cc_op)]++; \ 100 tot_evals++; \ 101 if (0 == (tot_evals & 0xFFFFF)) \ 102 showCounts(); \ 103 } while (0) 104 105 #endif /* PROFILE_NZCV_FLAGS */ 106 107 108 /* Calculate the N flag from the supplied thunk components, in the 109 least significant bit of the word. Returned bits 31:1 are zero. */ 110 static 111 UInt armg_calculate_flag_n ( UInt cc_op, UInt cc_dep1, 112 UInt cc_dep2, UInt cc_dep3 ) 113 { 114 # if PROFILE_NZCV_FLAGS 115 NOTE_N_EVAL(cc_op); 116 # endif 117 118 switch (cc_op) { 119 case ARMG_CC_OP_COPY: { 120 /* (nzcv:28x0, unused, unused) */ 121 UInt nf = (cc_dep1 >> ARMG_CC_SHIFT_N) & 1; 122 return nf; 123 } 124 case ARMG_CC_OP_ADD: { 125 /* (argL, argR, unused) */ 126 UInt argL = cc_dep1; 127 UInt argR = cc_dep2; 128 UInt res = argL + argR; 129 UInt nf = res >> 31; 130 return nf; 131 } 132 case ARMG_CC_OP_SUB: { 133 /* (argL, argR, unused) */ 134 UInt argL = cc_dep1; 135 UInt argR = cc_dep2; 136 UInt res = argL - argR; 137 UInt nf = res >> 31; 138 return nf; 139 } 140 case ARMG_CC_OP_ADC: { 141 /* (argL, argR, oldC) */ 142 UInt argL = cc_dep1; 143 UInt argR = cc_dep2; 144 UInt oldC = cc_dep3; 145 vassert((oldC & ~1) == 0); 146 UInt res = argL + argR + oldC; 147 UInt nf = res >> 31; 148 return nf; 149 } 150 case ARMG_CC_OP_SBB: { 151 /* (argL, argR, oldC) */ 152 UInt argL = cc_dep1; 153 UInt argR = cc_dep2; 154 UInt oldC = cc_dep3; 155 vassert((oldC & ~1) == 0); 156 UInt res = argL - argR - (oldC ^ 1); 157 UInt nf = res >> 31; 158 return nf; 159 } 160 case ARMG_CC_OP_LOGIC: { 161 /* (res, shco, oldV) */ 162 UInt res = cc_dep1; 163 UInt nf = res >> 31; 164 return nf; 165 } 166 case ARMG_CC_OP_MUL: { 167 /* (res, unused, oldC:oldV) */ 168 UInt res = cc_dep1; 169 UInt nf = res >> 31; 170 return nf; 171 } 172 case ARMG_CC_OP_MULL: { 173 /* (resLo32, resHi32, oldC:oldV) */ 174 UInt resHi32 = cc_dep2; 175 UInt nf = resHi32 >> 31; 176 return nf; 177 } 178 default: 179 /* shouldn't really make these calls from generated code */ 180 vex_printf("armg_calculate_flag_n" 181 "( op=%u, dep1=0x%x, dep2=0x%x, dep3=0x%x )\n", 182 cc_op, cc_dep1, cc_dep2, cc_dep3 ); 183 vpanic("armg_calculate_flags_n"); 184 } 185 } 186 187 188 /* Calculate the Z flag from the supplied thunk components, in the 189 least significant bit of the word. Returned bits 31:1 are zero. */ 190 static 191 UInt armg_calculate_flag_z ( UInt cc_op, UInt cc_dep1, 192 UInt cc_dep2, UInt cc_dep3 ) 193 { 194 # if PROFILE_NZCV_FLAGS 195 NOTE_Z_EVAL(cc_op); 196 # endif 197 198 switch (cc_op) { 199 case ARMG_CC_OP_COPY: { 200 /* (nzcv:28x0, unused, unused) */ 201 UInt zf = (cc_dep1 >> ARMG_CC_SHIFT_Z) & 1; 202 return zf; 203 } 204 case ARMG_CC_OP_ADD: { 205 /* (argL, argR, unused) */ 206 UInt argL = cc_dep1; 207 UInt argR = cc_dep2; 208 UInt res = argL + argR; 209 UInt zf = res == 0; 210 return zf; 211 } 212 case ARMG_CC_OP_SUB: { 213 /* (argL, argR, unused) */ 214 UInt argL = cc_dep1; 215 UInt argR = cc_dep2; 216 UInt res = argL - argR; 217 UInt zf = res == 0; 218 return zf; 219 } 220 case ARMG_CC_OP_ADC: { 221 /* (argL, argR, oldC) */ 222 UInt argL = cc_dep1; 223 UInt argR = cc_dep2; 224 UInt oldC = cc_dep3; 225 vassert((oldC & ~1) == 0); 226 UInt res = argL + argR + oldC; 227 UInt zf = res == 0; 228 return zf; 229 } 230 case ARMG_CC_OP_SBB: { 231 /* (argL, argR, oldC) */ 232 UInt argL = cc_dep1; 233 UInt argR = cc_dep2; 234 UInt oldC = cc_dep3; 235 vassert((oldC & ~1) == 0); 236 UInt res = argL - argR - (oldC ^ 1); 237 UInt zf = res == 0; 238 return zf; 239 } 240 case ARMG_CC_OP_LOGIC: { 241 /* (res, shco, oldV) */ 242 UInt res = cc_dep1; 243 UInt zf = res == 0; 244 return zf; 245 } 246 case ARMG_CC_OP_MUL: { 247 /* (res, unused, oldC:oldV) */ 248 UInt res = cc_dep1; 249 UInt zf = res == 0; 250 return zf; 251 } 252 case ARMG_CC_OP_MULL: { 253 /* (resLo32, resHi32, oldC:oldV) */ 254 UInt resLo32 = cc_dep1; 255 UInt resHi32 = cc_dep2; 256 UInt zf = (resHi32|resLo32) == 0; 257 return zf; 258 } 259 default: 260 /* shouldn't really make these calls from generated code */ 261 vex_printf("armg_calculate_flags_z" 262 "( op=%u, dep1=0x%x, dep2=0x%x, dep3=0x%x )\n", 263 cc_op, cc_dep1, cc_dep2, cc_dep3 ); 264 vpanic("armg_calculate_flags_z"); 265 } 266 } 267 268 269 /* CALLED FROM GENERATED CODE: CLEAN HELPER */ 270 /* Calculate the C flag from the supplied thunk components, in the 271 least significant bit of the word. Returned bits 31:1 are zero. */ 272 UInt armg_calculate_flag_c ( UInt cc_op, UInt cc_dep1, 273 UInt cc_dep2, UInt cc_dep3 ) 274 { 275 # if PROFILE_NZCV_FLAGS 276 NOTE_C_EVAL(cc_op); 277 # endif 278 279 switch (cc_op) { 280 case ARMG_CC_OP_COPY: { 281 /* (nzcv:28x0, unused, unused) */ 282 UInt cf = (cc_dep1 >> ARMG_CC_SHIFT_C) & 1; 283 return cf; 284 } 285 case ARMG_CC_OP_ADD: { 286 /* (argL, argR, unused) */ 287 UInt argL = cc_dep1; 288 UInt argR = cc_dep2; 289 UInt res = argL + argR; 290 UInt cf = res < argL; 291 return cf; 292 } 293 case ARMG_CC_OP_SUB: { 294 /* (argL, argR, unused) */ 295 UInt argL = cc_dep1; 296 UInt argR = cc_dep2; 297 UInt cf = argL >= argR; 298 return cf; 299 } 300 case ARMG_CC_OP_ADC: { 301 /* (argL, argR, oldC) */ 302 UInt argL = cc_dep1; 303 UInt argR = cc_dep2; 304 UInt oldC = cc_dep3; 305 vassert((oldC & ~1) == 0); 306 UInt res = argL + argR + oldC; 307 UInt cf = oldC ? (res <= argL) : (res < argL); 308 return cf; 309 } 310 case ARMG_CC_OP_SBB: { 311 /* (argL, argR, oldC) */ 312 UInt argL = cc_dep1; 313 UInt argR = cc_dep2; 314 UInt oldC = cc_dep3; 315 vassert((oldC & ~1) == 0); 316 UInt cf = oldC ? (argL >= argR) : (argL > argR); 317 return cf; 318 } 319 case ARMG_CC_OP_LOGIC: { 320 /* (res, shco, oldV) */ 321 UInt shco = cc_dep2; 322 vassert((shco & ~1) == 0); 323 UInt cf = shco; 324 return cf; 325 } 326 case ARMG_CC_OP_MUL: { 327 /* (res, unused, oldC:oldV) */ 328 UInt oldC = (cc_dep3 >> 1) & 1; 329 vassert((cc_dep3 & ~3) == 0); 330 UInt cf = oldC; 331 return cf; 332 } 333 case ARMG_CC_OP_MULL: { 334 /* (resLo32, resHi32, oldC:oldV) */ 335 UInt oldC = (cc_dep3 >> 1) & 1; 336 vassert((cc_dep3 & ~3) == 0); 337 UInt cf = oldC; 338 return cf; 339 } 340 default: 341 /* shouldn't really make these calls from generated code */ 342 vex_printf("armg_calculate_flag_c" 343 "( op=%u, dep1=0x%x, dep2=0x%x, dep3=0x%x )\n", 344 cc_op, cc_dep1, cc_dep2, cc_dep3 ); 345 vpanic("armg_calculate_flag_c"); 346 } 347 } 348 349 350 /* CALLED FROM GENERATED CODE: CLEAN HELPER */ 351 /* Calculate the V flag from the supplied thunk components, in the 352 least significant bit of the word. Returned bits 31:1 are zero. */ 353 UInt armg_calculate_flag_v ( UInt cc_op, UInt cc_dep1, 354 UInt cc_dep2, UInt cc_dep3 ) 355 { 356 # if PROFILE_NZCV_FLAGS 357 NOTE_V_EVAL(cc_op); 358 # endif 359 360 switch (cc_op) { 361 case ARMG_CC_OP_COPY: { 362 /* (nzcv:28x0, unused, unused) */ 363 UInt vf = (cc_dep1 >> ARMG_CC_SHIFT_V) & 1; 364 return vf; 365 } 366 case ARMG_CC_OP_ADD: { 367 /* (argL, argR, unused) */ 368 UInt argL = cc_dep1; 369 UInt argR = cc_dep2; 370 UInt res = argL + argR; 371 UInt vf = ((res ^ argL) & (res ^ argR)) >> 31; 372 return vf; 373 } 374 case ARMG_CC_OP_SUB: { 375 /* (argL, argR, unused) */ 376 UInt argL = cc_dep1; 377 UInt argR = cc_dep2; 378 UInt res = argL - argR; 379 UInt vf = ((argL ^ argR) & (argL ^ res)) >> 31; 380 return vf; 381 } 382 case ARMG_CC_OP_ADC: { 383 /* (argL, argR, oldC) */ 384 UInt argL = cc_dep1; 385 UInt argR = cc_dep2; 386 UInt oldC = cc_dep3; 387 vassert((oldC & ~1) == 0); 388 UInt res = argL + argR + oldC; 389 UInt vf = ((res ^ argL) & (res ^ argR)) >> 31; 390 return vf; 391 } 392 case ARMG_CC_OP_SBB: { 393 /* (argL, argR, oldC) */ 394 UInt argL = cc_dep1; 395 UInt argR = cc_dep2; 396 UInt oldC = cc_dep3; 397 vassert((oldC & ~1) == 0); 398 UInt res = argL - argR - (oldC ^ 1); 399 UInt vf = ((argL ^ argR) & (argL ^ res)) >> 31; 400 return vf; 401 } 402 case ARMG_CC_OP_LOGIC: { 403 /* (res, shco, oldV) */ 404 UInt oldV = cc_dep3; 405 vassert((oldV & ~1) == 0); 406 UInt vf = oldV; 407 return vf; 408 } 409 case ARMG_CC_OP_MUL: { 410 /* (res, unused, oldC:oldV) */ 411 UInt oldV = (cc_dep3 >> 0) & 1; 412 vassert((cc_dep3 & ~3) == 0); 413 UInt vf = oldV; 414 return vf; 415 } 416 case ARMG_CC_OP_MULL: { 417 /* (resLo32, resHi32, oldC:oldV) */ 418 UInt oldV = (cc_dep3 >> 0) & 1; 419 vassert((cc_dep3 & ~3) == 0); 420 UInt vf = oldV; 421 return vf; 422 } 423 default: 424 /* shouldn't really make these calls from generated code */ 425 vex_printf("armg_calculate_flag_v" 426 "( op=%u, dep1=0x%x, dep2=0x%x, dep3=0x%x )\n", 427 cc_op, cc_dep1, cc_dep2, cc_dep3 ); 428 vpanic("armg_calculate_flag_v"); 429 } 430 } 431 432 433 /* CALLED FROM GENERATED CODE: CLEAN HELPER */ 434 /* Calculate NZCV from the supplied thunk components, in the positions 435 they appear in the CPSR, viz bits 31:28 for N Z C V respectively. 436 Returned bits 27:0 are zero. */ 437 UInt armg_calculate_flags_nzcv ( UInt cc_op, UInt cc_dep1, 438 UInt cc_dep2, UInt cc_dep3 ) 439 { 440 UInt f; 441 UInt res = 0; 442 f = armg_calculate_flag_n(cc_op, cc_dep1, cc_dep2, cc_dep3); 443 res |= (f << ARMG_CC_SHIFT_N); 444 f = armg_calculate_flag_z(cc_op, cc_dep1, cc_dep2, cc_dep3); 445 res |= (f << ARMG_CC_SHIFT_Z); 446 f = armg_calculate_flag_c(cc_op, cc_dep1, cc_dep2, cc_dep3); 447 res |= (f << ARMG_CC_SHIFT_C); 448 f = armg_calculate_flag_v(cc_op, cc_dep1, cc_dep2, cc_dep3); 449 res |= (f << ARMG_CC_SHIFT_V); 450 return res; 451 } 452 453 454 /* CALLED FROM GENERATED CODE: CLEAN HELPER */ 455 /* Calculate the QC flag from the arguments, in the lowest bit 456 of the word (bit 0). Urr, having this out of line is bizarre. 457 Push back inline. */ 458 UInt armg_calculate_flag_qc ( UInt resL1, UInt resL2, 459 UInt resR1, UInt resR2 ) 460 { 461 if (resL1 != resR1 || resL2 != resR2) 462 return 1; 463 else 464 return 0; 465 } 466 467 /* CALLED FROM GENERATED CODE: CLEAN HELPER */ 468 /* Calculate the specified condition from the thunk components, in the 469 lowest bit of the word (bit 0). Returned bits 31:1 are zero. */ 470 UInt armg_calculate_condition ( UInt cond_n_op /* (ARMCondcode << 4) | cc_op */, 471 UInt cc_dep1, 472 UInt cc_dep2, UInt cc_dep3 ) 473 { 474 UInt cond = cond_n_op >> 4; 475 UInt cc_op = cond_n_op & 0xF; 476 UInt nf, zf, vf, cf, inv; 477 // vex_printf("XXXXXXXX %x %x %x %x\n", 478 // cond_n_op, cc_dep1, cc_dep2, cc_dep3); 479 480 // skip flags computation in this case 481 if (cond == ARMCondAL) return 1; 482 483 inv = cond & 1; 484 485 switch (cond) { 486 case ARMCondEQ: // Z=1 => z 487 case ARMCondNE: // Z=0 488 zf = armg_calculate_flag_z(cc_op, cc_dep1, cc_dep2, cc_dep3); 489 return inv ^ zf; 490 491 case ARMCondHS: // C=1 => c 492 case ARMCondLO: // C=0 493 cf = armg_calculate_flag_c(cc_op, cc_dep1, cc_dep2, cc_dep3); 494 return inv ^ cf; 495 496 case ARMCondMI: // N=1 => n 497 case ARMCondPL: // N=0 498 nf = armg_calculate_flag_n(cc_op, cc_dep1, cc_dep2, cc_dep3); 499 return inv ^ nf; 500 501 case ARMCondVS: // V=1 => v 502 case ARMCondVC: // V=0 503 vf = armg_calculate_flag_v(cc_op, cc_dep1, cc_dep2, cc_dep3); 504 return inv ^ vf; 505 506 case ARMCondHI: // C=1 && Z=0 => c & ~z 507 case ARMCondLS: // C=0 || Z=1 508 cf = armg_calculate_flag_c(cc_op, cc_dep1, cc_dep2, cc_dep3); 509 zf = armg_calculate_flag_z(cc_op, cc_dep1, cc_dep2, cc_dep3); 510 return inv ^ (1 & (cf & ~zf)); 511 512 case ARMCondGE: // N=V => ~(n^v) 513 case ARMCondLT: // N!=V 514 nf = armg_calculate_flag_n(cc_op, cc_dep1, cc_dep2, cc_dep3); 515 vf = armg_calculate_flag_v(cc_op, cc_dep1, cc_dep2, cc_dep3); 516 return inv ^ (1 & ~(nf ^ vf)); 517 518 case ARMCondGT: // Z=0 && N=V => ~z & ~(n^v) => ~(z | (n^v)) 519 case ARMCondLE: // Z=1 || N!=V 520 nf = armg_calculate_flag_n(cc_op, cc_dep1, cc_dep2, cc_dep3); 521 vf = armg_calculate_flag_v(cc_op, cc_dep1, cc_dep2, cc_dep3); 522 zf = armg_calculate_flag_z(cc_op, cc_dep1, cc_dep2, cc_dep3); 523 return inv ^ (1 & ~(zf | (nf ^ vf))); 524 525 case ARMCondAL: // handled above 526 case ARMCondNV: // should never get here: Illegal instr 527 default: 528 /* shouldn't really make these calls from generated code */ 529 vex_printf("armg_calculate_condition(ARM)" 530 "( %u, %u, 0x%x, 0x%x, 0x%x )\n", 531 cond, cc_op, cc_dep1, cc_dep2, cc_dep3 ); 532 vpanic("armg_calculate_condition(ARM)"); 533 } 534 } 535 536 537 /*---------------------------------------------------------------*/ 538 /*--- Flag-helpers translation-time function specialisers. ---*/ 539 /*--- These help iropt specialise calls the above run-time ---*/ 540 /*--- flags functions. ---*/ 541 /*---------------------------------------------------------------*/ 542 543 /* Used by the optimiser to try specialisations. Returns an 544 equivalent expression, or NULL if none. */ 545 546 static Bool isU32 ( IRExpr* e, UInt n ) 547 { 548 return 549 toBool( e->tag == Iex_Const 550 && e->Iex.Const.con->tag == Ico_U32 551 && e->Iex.Const.con->Ico.U32 == n ); 552 } 553 554 IRExpr* guest_arm_spechelper ( const HChar* function_name, 555 IRExpr** args, 556 IRStmt** precedingStmts, 557 Int n_precedingStmts ) 558 { 559 # define unop(_op,_a1) IRExpr_Unop((_op),(_a1)) 560 # define binop(_op,_a1,_a2) IRExpr_Binop((_op),(_a1),(_a2)) 561 # define mkU32(_n) IRExpr_Const(IRConst_U32(_n)) 562 # define mkU8(_n) IRExpr_Const(IRConst_U8(_n)) 563 564 Int i, arity = 0; 565 for (i = 0; args[i]; i++) 566 arity++; 567 # if 0 568 vex_printf("spec request:\n"); 569 vex_printf(" %s ", function_name); 570 for (i = 0; i < arity; i++) { 571 vex_printf(" "); 572 ppIRExpr(args[i]); 573 } 574 vex_printf("\n"); 575 # endif 576 577 /* --------- specialising "armg_calculate_condition" --------- */ 578 579 if (vex_streq(function_name, "armg_calculate_condition")) { 580 581 /* specialise calls to the "armg_calculate_condition" function. 582 Not sure whether this is strictly necessary, but: the 583 replacement IR must produce only the values 0 or 1. Bits 584 31:1 are required to be zero. */ 585 IRExpr *cond_n_op, *cc_dep1, *cc_dep2, *cc_ndep; 586 vassert(arity == 4); 587 cond_n_op = args[0]; /* (ARMCondcode << 4) | ARMG_CC_OP_* */ 588 cc_dep1 = args[1]; 589 cc_dep2 = args[2]; 590 cc_ndep = args[3]; 591 592 /*---------------- SUB ----------------*/ 593 594 if (isU32(cond_n_op, (ARMCondEQ << 4) | ARMG_CC_OP_SUB)) { 595 /* EQ after SUB --> test argL == argR */ 596 return unop(Iop_1Uto32, 597 binop(Iop_CmpEQ32, cc_dep1, cc_dep2)); 598 } 599 if (isU32(cond_n_op, (ARMCondNE << 4) | ARMG_CC_OP_SUB)) { 600 /* NE after SUB --> test argL != argR */ 601 return unop(Iop_1Uto32, 602 binop(Iop_CmpNE32, cc_dep1, cc_dep2)); 603 } 604 605 if (isU32(cond_n_op, (ARMCondGT << 4) | ARMG_CC_OP_SUB)) { 606 /* GT after SUB --> test argL >s argR 607 --> test argR <s argL */ 608 return unop(Iop_1Uto32, 609 binop(Iop_CmpLT32S, cc_dep2, cc_dep1)); 610 } 611 if (isU32(cond_n_op, (ARMCondLE << 4) | ARMG_CC_OP_SUB)) { 612 /* LE after SUB --> test argL <=s argR */ 613 return unop(Iop_1Uto32, 614 binop(Iop_CmpLE32S, cc_dep1, cc_dep2)); 615 } 616 617 if (isU32(cond_n_op, (ARMCondLT << 4) | ARMG_CC_OP_SUB)) { 618 /* LT after SUB --> test argL <s argR */ 619 return unop(Iop_1Uto32, 620 binop(Iop_CmpLT32S, cc_dep1, cc_dep2)); 621 } 622 623 if (isU32(cond_n_op, (ARMCondGE << 4) | ARMG_CC_OP_SUB)) { 624 /* GE after SUB --> test argL >=s argR 625 --> test argR <=s argL */ 626 return unop(Iop_1Uto32, 627 binop(Iop_CmpLE32S, cc_dep2, cc_dep1)); 628 } 629 630 if (isU32(cond_n_op, (ARMCondHS << 4) | ARMG_CC_OP_SUB)) { 631 /* HS after SUB --> test argL >=u argR 632 --> test argR <=u argL */ 633 return unop(Iop_1Uto32, 634 binop(Iop_CmpLE32U, cc_dep2, cc_dep1)); 635 } 636 if (isU32(cond_n_op, (ARMCondLO << 4) | ARMG_CC_OP_SUB)) { 637 /* LO after SUB --> test argL <u argR */ 638 return unop(Iop_1Uto32, 639 binop(Iop_CmpLT32U, cc_dep1, cc_dep2)); 640 } 641 642 if (isU32(cond_n_op, (ARMCondLS << 4) | ARMG_CC_OP_SUB)) { 643 /* LS after SUB --> test argL <=u argR */ 644 return unop(Iop_1Uto32, 645 binop(Iop_CmpLE32U, cc_dep1, cc_dep2)); 646 } 647 if (isU32(cond_n_op, (ARMCondHI << 4) | ARMG_CC_OP_SUB)) { 648 /* HI after SUB --> test argL >u argR 649 --> test argR <u argL */ 650 return unop(Iop_1Uto32, 651 binop(Iop_CmpLT32U, cc_dep2, cc_dep1)); 652 } 653 654 /*---------------- SBB ----------------*/ 655 656 if (isU32(cond_n_op, (ARMCondHS << 4) | ARMG_CC_OP_SBB)) { 657 /* This seems to happen a lot in softfloat code, eg __divdf3+140 */ 658 /* thunk is: (dep1=argL, dep2=argR, ndep=oldC) */ 659 /* HS after SBB (same as C after SBB below) 660 --> oldC ? (argL >=u argR) : (argL >u argR) 661 --> oldC ? (argR <=u argL) : (argR <u argL) 662 */ 663 return 664 IRExpr_ITE( 665 binop(Iop_CmpNE32, cc_ndep, mkU32(0)), 666 /* case oldC != 0 */ 667 unop(Iop_1Uto32, binop(Iop_CmpLE32U, cc_dep2, cc_dep1)), 668 /* case oldC == 0 */ 669 unop(Iop_1Uto32, binop(Iop_CmpLT32U, cc_dep2, cc_dep1)) 670 ); 671 } 672 673 /*---------------- LOGIC ----------------*/ 674 675 if (isU32(cond_n_op, (ARMCondEQ << 4) | ARMG_CC_OP_LOGIC)) { 676 /* EQ after LOGIC --> test res == 0 */ 677 return unop(Iop_1Uto32, 678 binop(Iop_CmpEQ32, cc_dep1, mkU32(0))); 679 } 680 if (isU32(cond_n_op, (ARMCondNE << 4) | ARMG_CC_OP_LOGIC)) { 681 /* NE after LOGIC --> test res != 0 */ 682 return unop(Iop_1Uto32, 683 binop(Iop_CmpNE32, cc_dep1, mkU32(0))); 684 } 685 686 if (isU32(cond_n_op, (ARMCondPL << 4) | ARMG_CC_OP_LOGIC)) { 687 /* PL after LOGIC --> test (res >> 31) == 0 */ 688 return unop(Iop_1Uto32, 689 binop(Iop_CmpEQ32, 690 binop(Iop_Shr32, cc_dep1, mkU8(31)), 691 mkU32(0))); 692 } 693 if (isU32(cond_n_op, (ARMCondMI << 4) | ARMG_CC_OP_LOGIC)) { 694 /* MI after LOGIC --> test (res >> 31) == 1 */ 695 return unop(Iop_1Uto32, 696 binop(Iop_CmpEQ32, 697 binop(Iop_Shr32, cc_dep1, mkU8(31)), 698 mkU32(1))); 699 } 700 701 /*---------------- COPY ----------------*/ 702 703 if (isU32(cond_n_op, (ARMCondNE << 4) | ARMG_CC_OP_COPY)) { 704 /* NE after COPY --> ((cc_dep1 >> ARMG_CC_SHIFT_Z) ^ 1) & 1 */ 705 return binop(Iop_And32, 706 binop(Iop_Xor32, 707 binop(Iop_Shr32, cc_dep1, 708 mkU8(ARMG_CC_SHIFT_Z)), 709 mkU32(1)), 710 mkU32(1)); 711 } 712 713 /*----------------- AL -----------------*/ 714 715 /* A critically important case for Thumb code. 716 717 What we're trying to spot is the case where cond_n_op is an 718 expression of the form Or32(..., 0xE0) since that means the 719 caller is asking for CondAL and we can simply return 1 720 without caring what the ... part is. This is a potentially 721 dodgy kludge in that it assumes that the ... part has zeroes 722 in bits 7:4, so that the result of the Or32 is guaranteed to 723 be 0xE in bits 7:4. Given that the places where this first 724 arg are constructed (in guest_arm_toIR.c) are very 725 constrained, we can get away with this. To make this 726 guaranteed safe would require to have a new primop, Slice44 727 or some such, thusly 728 729 Slice44(arg1, arg2) = 0--(24)--0 arg1[7:4] arg2[3:0] 730 731 and we would then look for Slice44(0xE0, ...) 732 which would give the required safety property. 733 734 It would be infeasibly expensive to scan backwards through 735 the entire block looking for an assignment to the temp, so 736 just look at the previous 16 statements. That should find it 737 if it is an interesting case, as a result of how the 738 boilerplate guff at the start of each Thumb insn translation 739 is made. 740 */ 741 if (cond_n_op->tag == Iex_RdTmp) { 742 Int j; 743 IRTemp look_for = cond_n_op->Iex.RdTmp.tmp; 744 Int limit = n_precedingStmts - 16; 745 if (limit < 0) limit = 0; 746 if (0) vex_printf("scanning %d .. %d\n", n_precedingStmts-1, limit); 747 for (j = n_precedingStmts - 1; j >= limit; j--) { 748 IRStmt* st = precedingStmts[j]; 749 if (st->tag == Ist_WrTmp 750 && st->Ist.WrTmp.tmp == look_for 751 && st->Ist.WrTmp.data->tag == Iex_Binop 752 && st->Ist.WrTmp.data->Iex.Binop.op == Iop_Or32 753 && isU32(st->Ist.WrTmp.data->Iex.Binop.arg2, (ARMCondAL << 4))) 754 return mkU32(1); 755 } 756 /* Didn't find any useful binding to the first arg 757 in the previous 16 stmts. */ 758 } 759 } 760 761 /* --------- specialising "armg_calculate_flag_c" --------- */ 762 763 else 764 if (vex_streq(function_name, "armg_calculate_flag_c")) { 765 766 /* specialise calls to the "armg_calculate_flag_c" function. 767 Note that the returned value must be either 0 or 1; nonzero 768 bits 31:1 are not allowed. In turn, incoming oldV and oldC 769 values (from the thunk) are assumed to have bits 31:1 770 clear. */ 771 IRExpr *cc_op, *cc_dep1, *cc_dep2, *cc_ndep; 772 vassert(arity == 4); 773 cc_op = args[0]; /* ARMG_CC_OP_* */ 774 cc_dep1 = args[1]; 775 cc_dep2 = args[2]; 776 cc_ndep = args[3]; 777 778 if (isU32(cc_op, ARMG_CC_OP_LOGIC)) { 779 /* Thunk args are (result, shco, oldV) */ 780 /* C after LOGIC --> shco */ 781 return cc_dep2; 782 } 783 784 if (isU32(cc_op, ARMG_CC_OP_SUB)) { 785 /* Thunk args are (argL, argR, unused) */ 786 /* C after SUB --> argL >=u argR 787 --> argR <=u argL */ 788 return unop(Iop_1Uto32, 789 binop(Iop_CmpLE32U, cc_dep2, cc_dep1)); 790 } 791 792 if (isU32(cc_op, ARMG_CC_OP_SBB)) { 793 /* This happens occasionally in softfloat code, eg __divdf3+140 */ 794 /* thunk is: (dep1=argL, dep2=argR, ndep=oldC) */ 795 /* C after SBB (same as HS after SBB above) 796 --> oldC ? (argL >=u argR) : (argL >u argR) 797 --> oldC ? (argR <=u argL) : (argR <u argL) 798 */ 799 return 800 IRExpr_ITE( 801 binop(Iop_CmpNE32, cc_ndep, mkU32(0)), 802 /* case oldC != 0 */ 803 unop(Iop_1Uto32, binop(Iop_CmpLE32U, cc_dep2, cc_dep1)), 804 /* case oldC == 0 */ 805 unop(Iop_1Uto32, binop(Iop_CmpLT32U, cc_dep2, cc_dep1)) 806 ); 807 } 808 809 } 810 811 /* --------- specialising "armg_calculate_flag_v" --------- */ 812 813 else 814 if (vex_streq(function_name, "armg_calculate_flag_v")) { 815 816 /* specialise calls to the "armg_calculate_flag_v" function. 817 Note that the returned value must be either 0 or 1; nonzero 818 bits 31:1 are not allowed. In turn, incoming oldV and oldC 819 values (from the thunk) are assumed to have bits 31:1 820 clear. */ 821 IRExpr *cc_op, *cc_dep1, *cc_dep2, *cc_ndep; 822 vassert(arity == 4); 823 cc_op = args[0]; /* ARMG_CC_OP_* */ 824 cc_dep1 = args[1]; 825 cc_dep2 = args[2]; 826 cc_ndep = args[3]; 827 828 if (isU32(cc_op, ARMG_CC_OP_LOGIC)) { 829 /* Thunk args are (result, shco, oldV) */ 830 /* V after LOGIC --> oldV */ 831 return cc_ndep; 832 } 833 834 if (isU32(cc_op, ARMG_CC_OP_SUB)) { 835 /* Thunk args are (argL, argR, unused) */ 836 /* V after SUB 837 --> let res = argL - argR 838 in ((argL ^ argR) & (argL ^ res)) >> 31 839 --> ((argL ^ argR) & (argL ^ (argL - argR))) >> 31 840 */ 841 IRExpr* argL = cc_dep1; 842 IRExpr* argR = cc_dep2; 843 return 844 binop(Iop_Shr32, 845 binop(Iop_And32, 846 binop(Iop_Xor32, argL, argR), 847 binop(Iop_Xor32, argL, binop(Iop_Sub32, argL, argR)) 848 ), 849 mkU8(31) 850 ); 851 } 852 853 if (isU32(cc_op, ARMG_CC_OP_SBB)) { 854 /* This happens occasionally in softfloat code, eg __divdf3+140 */ 855 /* thunk is: (dep1=argL, dep2=argR, ndep=oldC) */ 856 /* V after SBB 857 --> let res = argL - argR - (oldC ^ 1) 858 in (argL ^ argR) & (argL ^ res) & 1 859 */ 860 return 861 binop( 862 Iop_And32, 863 binop( 864 Iop_And32, 865 // argL ^ argR 866 binop(Iop_Xor32, cc_dep1, cc_dep2), 867 // argL ^ (argL - argR - (oldC ^ 1)) 868 binop(Iop_Xor32, 869 cc_dep1, 870 binop(Iop_Sub32, 871 binop(Iop_Sub32, cc_dep1, cc_dep2), 872 binop(Iop_Xor32, cc_ndep, mkU32(1))) 873 ) 874 ), 875 mkU32(1) 876 ); 877 } 878 879 } 880 881 # undef unop 882 # undef binop 883 # undef mkU32 884 # undef mkU8 885 886 return NULL; 887 } 888 889 890 /*----------------------------------------------*/ 891 /*--- The exported fns .. ---*/ 892 /*----------------------------------------------*/ 893 894 /* VISIBLE TO LIBVEX CLIENT */ 895 #if 0 896 void LibVEX_GuestARM_put_flags ( UInt flags_native, 897 /*OUT*/VexGuestARMState* vex_state ) 898 { 899 vassert(0); // FIXME 900 901 /* Mask out everything except N Z V C. */ 902 flags_native 903 &= (ARMG_CC_MASK_N | ARMG_CC_MASK_Z | ARMG_CC_MASK_V | ARMG_CC_MASK_C); 904 905 vex_state->guest_CC_OP = ARMG_CC_OP_COPY; 906 vex_state->guest_CC_DEP1 = flags_native; 907 vex_state->guest_CC_DEP2 = 0; 908 vex_state->guest_CC_NDEP = 0; 909 } 910 #endif 911 912 /* VISIBLE TO LIBVEX CLIENT */ 913 UInt LibVEX_GuestARM_get_cpsr ( /*IN*/const VexGuestARMState* vex_state ) 914 { 915 UInt cpsr = 0; 916 // NZCV 917 cpsr |= armg_calculate_flags_nzcv( 918 vex_state->guest_CC_OP, 919 vex_state->guest_CC_DEP1, 920 vex_state->guest_CC_DEP2, 921 vex_state->guest_CC_NDEP 922 ); 923 vassert(0 == (cpsr & 0x0FFFFFFF)); 924 // Q 925 if (vex_state->guest_QFLAG32 > 0) 926 cpsr |= (1 << 27); 927 // GE 928 if (vex_state->guest_GEFLAG0 > 0) 929 cpsr |= (1 << 16); 930 if (vex_state->guest_GEFLAG1 > 0) 931 cpsr |= (1 << 17); 932 if (vex_state->guest_GEFLAG2 > 0) 933 cpsr |= (1 << 18); 934 if (vex_state->guest_GEFLAG3 > 0) 935 cpsr |= (1 << 19); 936 // M 937 cpsr |= (1 << 4); // 0b10000 means user-mode 938 // J,T J (bit 24) is zero by initialisation above 939 // T we copy from R15T[0] 940 if (vex_state->guest_R15T & 1) 941 cpsr |= (1 << 5); 942 // ITSTATE we punt on for the time being. Could compute it 943 // if needed though. 944 // E, endianness, 0 (littleendian) from initialisation above 945 // A,I,F disable some async exceptions. Not sure about these. 946 // Leave as zero for the time being. 947 return cpsr; 948 } 949 950 /* VISIBLE TO LIBVEX CLIENT */ 951 void LibVEX_GuestARM_initialise ( /*OUT*/VexGuestARMState* vex_state ) 952 { 953 vex_state->host_EvC_FAILADDR = 0; 954 vex_state->host_EvC_COUNTER = 0; 955 956 vex_state->guest_R0 = 0; 957 vex_state->guest_R1 = 0; 958 vex_state->guest_R2 = 0; 959 vex_state->guest_R3 = 0; 960 vex_state->guest_R4 = 0; 961 vex_state->guest_R5 = 0; 962 vex_state->guest_R6 = 0; 963 vex_state->guest_R7 = 0; 964 vex_state->guest_R8 = 0; 965 vex_state->guest_R9 = 0; 966 vex_state->guest_R10 = 0; 967 vex_state->guest_R11 = 0; 968 vex_state->guest_R12 = 0; 969 vex_state->guest_R13 = 0; 970 vex_state->guest_R14 = 0; 971 vex_state->guest_R15T = 0; /* NB: implies ARM mode */ 972 973 vex_state->guest_CC_OP = ARMG_CC_OP_COPY; 974 vex_state->guest_CC_DEP1 = 0; 975 vex_state->guest_CC_DEP2 = 0; 976 vex_state->guest_CC_NDEP = 0; 977 vex_state->guest_QFLAG32 = 0; 978 vex_state->guest_GEFLAG0 = 0; 979 vex_state->guest_GEFLAG1 = 0; 980 vex_state->guest_GEFLAG2 = 0; 981 vex_state->guest_GEFLAG3 = 0; 982 983 vex_state->guest_EMNOTE = EmNote_NONE; 984 vex_state->guest_CMSTART = 0; 985 vex_state->guest_CMLEN = 0; 986 vex_state->guest_NRADDR = 0; 987 vex_state->guest_IP_AT_SYSCALL = 0; 988 989 vex_state->guest_D0 = 0; 990 vex_state->guest_D1 = 0; 991 vex_state->guest_D2 = 0; 992 vex_state->guest_D3 = 0; 993 vex_state->guest_D4 = 0; 994 vex_state->guest_D5 = 0; 995 vex_state->guest_D6 = 0; 996 vex_state->guest_D7 = 0; 997 vex_state->guest_D8 = 0; 998 vex_state->guest_D9 = 0; 999 vex_state->guest_D10 = 0; 1000 vex_state->guest_D11 = 0; 1001 vex_state->guest_D12 = 0; 1002 vex_state->guest_D13 = 0; 1003 vex_state->guest_D14 = 0; 1004 vex_state->guest_D15 = 0; 1005 vex_state->guest_D16 = 0; 1006 vex_state->guest_D17 = 0; 1007 vex_state->guest_D18 = 0; 1008 vex_state->guest_D19 = 0; 1009 vex_state->guest_D20 = 0; 1010 vex_state->guest_D21 = 0; 1011 vex_state->guest_D22 = 0; 1012 vex_state->guest_D23 = 0; 1013 vex_state->guest_D24 = 0; 1014 vex_state->guest_D25 = 0; 1015 vex_state->guest_D26 = 0; 1016 vex_state->guest_D27 = 0; 1017 vex_state->guest_D28 = 0; 1018 vex_state->guest_D29 = 0; 1019 vex_state->guest_D30 = 0; 1020 vex_state->guest_D31 = 0; 1021 1022 /* ARM encoded; zero is the default as it happens (result flags 1023 (NZCV) cleared, FZ disabled, round to nearest, non-vector mode, 1024 all exns masked, all exn sticky bits cleared). */ 1025 vex_state->guest_FPSCR = 0; 1026 1027 vex_state->guest_TPIDRURO = 0; 1028 1029 /* Not in a Thumb IT block. */ 1030 vex_state->guest_ITSTATE = 0; 1031 1032 vex_state->padding1 = 0; 1033 } 1034 1035 1036 /*-----------------------------------------------------------*/ 1037 /*--- Describing the arm guest state, for the benefit ---*/ 1038 /*--- of iropt and instrumenters. ---*/ 1039 /*-----------------------------------------------------------*/ 1040 1041 /* Figure out if any part of the guest state contained in minoff 1042 .. maxoff requires precise memory exceptions. If in doubt return 1043 True (but this generates significantly slower code). 1044 1045 We enforce precise exns for guest R13(sp), R15T(pc), R7, R11. 1046 1047 1048 Only R13(sp) is needed in mode VexRegUpdSpAtMemAccess. 1049 */ 1050 Bool guest_arm_state_requires_precise_mem_exns ( Int minoff, 1051 Int maxoff) 1052 { 1053 Int sp_min = offsetof(VexGuestARMState, guest_R13); 1054 Int sp_max = sp_min + 4 - 1; 1055 Int pc_min = offsetof(VexGuestARMState, guest_R15T); 1056 Int pc_max = pc_min + 4 - 1; 1057 1058 if (maxoff < sp_min || minoff > sp_max) { 1059 /* no overlap with sp */ 1060 if (vex_control.iropt_register_updates == VexRegUpdSpAtMemAccess) 1061 return False; // We only need to check stack pointer. 1062 } else { 1063 return True; 1064 } 1065 1066 if (maxoff < pc_min || minoff > pc_max) { 1067 /* no overlap with pc */ 1068 } else { 1069 return True; 1070 } 1071 1072 /* We appear to need precise updates of R11 in order to get proper 1073 stacktraces from non-optimised code. */ 1074 Int r11_min = offsetof(VexGuestARMState, guest_R11); 1075 Int r11_max = r11_min + 4 - 1; 1076 1077 if (maxoff < r11_min || minoff > r11_max) { 1078 /* no overlap with r11 */ 1079 } else { 1080 return True; 1081 } 1082 1083 /* Ditto R7, particularly needed for proper stacktraces in Thumb 1084 code. */ 1085 Int r7_min = offsetof(VexGuestARMState, guest_R7); 1086 Int r7_max = r7_min + 4 - 1; 1087 1088 if (maxoff < r7_min || minoff > r7_max) { 1089 /* no overlap with r7 */ 1090 } else { 1091 return True; 1092 } 1093 1094 return False; 1095 } 1096 1097 1098 1099 #define ALWAYSDEFD(field) \ 1100 { offsetof(VexGuestARMState, field), \ 1101 (sizeof ((VexGuestARMState*)0)->field) } 1102 1103 VexGuestLayout 1104 armGuest_layout 1105 = { 1106 /* Total size of the guest state, in bytes. */ 1107 .total_sizeB = sizeof(VexGuestARMState), 1108 1109 /* Describe the stack pointer. */ 1110 .offset_SP = offsetof(VexGuestARMState,guest_R13), 1111 .sizeof_SP = 4, 1112 1113 /* Describe the instruction pointer. */ 1114 .offset_IP = offsetof(VexGuestARMState,guest_R15T), 1115 .sizeof_IP = 4, 1116 1117 /* Describe any sections to be regarded by Memcheck as 1118 'always-defined'. */ 1119 .n_alwaysDefd = 10, 1120 1121 /* flags thunk: OP is always defd, whereas DEP1 and DEP2 1122 have to be tracked. See detailed comment in gdefs.h on 1123 meaning of thunk fields. */ 1124 .alwaysDefd 1125 = { /* 0 */ ALWAYSDEFD(guest_R15T), 1126 /* 1 */ ALWAYSDEFD(guest_CC_OP), 1127 /* 2 */ ALWAYSDEFD(guest_CC_NDEP), 1128 /* 3 */ ALWAYSDEFD(guest_EMNOTE), 1129 /* 4 */ ALWAYSDEFD(guest_CMSTART), 1130 /* 5 */ ALWAYSDEFD(guest_CMLEN), 1131 /* 6 */ ALWAYSDEFD(guest_NRADDR), 1132 /* 7 */ ALWAYSDEFD(guest_IP_AT_SYSCALL), 1133 /* 8 */ ALWAYSDEFD(guest_TPIDRURO), 1134 /* 9 */ ALWAYSDEFD(guest_ITSTATE) 1135 } 1136 }; 1137 1138 1139 /*---------------------------------------------------------------*/ 1140 /*--- end guest_arm_helpers.c ---*/ 1141 /*---------------------------------------------------------------*/ 1142
