1 //===- MCExpr.cpp - Assembly Level Expression Implementation --------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #define DEBUG_TYPE "mcexpr" 11 #include "llvm/MC/MCExpr.h" 12 #include "llvm/ADT/Statistic.h" 13 #include "llvm/ADT/StringSwitch.h" 14 #include "llvm/MC/MCAsmLayout.h" 15 #include "llvm/MC/MCAssembler.h" 16 #include "llvm/MC/MCContext.h" 17 #include "llvm/MC/MCObjectWriter.h" 18 #include "llvm/MC/MCSymbol.h" 19 #include "llvm/MC/MCValue.h" 20 #include "llvm/Support/Debug.h" 21 #include "llvm/Support/ErrorHandling.h" 22 #include "llvm/Support/raw_ostream.h" 23 using namespace llvm; 24 25 namespace { 26 namespace stats { 27 STATISTIC(MCExprEvaluate, "Number of MCExpr evaluations"); 28 } 29 } 30 31 void MCExpr::print(raw_ostream &OS) const { 32 switch (getKind()) { 33 case MCExpr::Target: 34 return cast<MCTargetExpr>(this)->PrintImpl(OS); 35 case MCExpr::Constant: 36 OS << cast<MCConstantExpr>(*this).getValue(); 37 return; 38 39 case MCExpr::SymbolRef: { 40 const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this); 41 const MCSymbol &Sym = SRE.getSymbol(); 42 // Parenthesize names that start with $ so that they don't look like 43 // absolute names. 44 bool UseParens = Sym.getName()[0] == '$'; 45 46 if (SRE.getKind() == MCSymbolRefExpr::VK_PPC_DARWIN_HA16 || 47 SRE.getKind() == MCSymbolRefExpr::VK_PPC_DARWIN_LO16) { 48 OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind()); 49 UseParens = true; 50 } 51 52 if (UseParens) 53 OS << '(' << Sym << ')'; 54 else 55 OS << Sym; 56 57 if (SRE.getKind() == MCSymbolRefExpr::VK_ARM_PLT || 58 SRE.getKind() == MCSymbolRefExpr::VK_ARM_TLSGD || 59 SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOT || 60 SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTOFF || 61 SRE.getKind() == MCSymbolRefExpr::VK_ARM_TPOFF || 62 SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTTPOFF || 63 SRE.getKind() == MCSymbolRefExpr::VK_ARM_TARGET1) 64 OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind()); 65 else if (SRE.getKind() != MCSymbolRefExpr::VK_None && 66 SRE.getKind() != MCSymbolRefExpr::VK_PPC_DARWIN_HA16 && 67 SRE.getKind() != MCSymbolRefExpr::VK_PPC_DARWIN_LO16) 68 OS << '@' << MCSymbolRefExpr::getVariantKindName(SRE.getKind()); 69 70 return; 71 } 72 73 case MCExpr::Unary: { 74 const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this); 75 switch (UE.getOpcode()) { 76 case MCUnaryExpr::LNot: OS << '!'; break; 77 case MCUnaryExpr::Minus: OS << '-'; break; 78 case MCUnaryExpr::Not: OS << '~'; break; 79 case MCUnaryExpr::Plus: OS << '+'; break; 80 } 81 OS << *UE.getSubExpr(); 82 return; 83 } 84 85 case MCExpr::Binary: { 86 const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this); 87 88 // Only print parens around the LHS if it is non-trivial. 89 if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) { 90 OS << *BE.getLHS(); 91 } else { 92 OS << '(' << *BE.getLHS() << ')'; 93 } 94 95 switch (BE.getOpcode()) { 96 case MCBinaryExpr::Add: 97 // Print "X-42" instead of "X+-42". 98 if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) { 99 if (RHSC->getValue() < 0) { 100 OS << RHSC->getValue(); 101 return; 102 } 103 } 104 105 OS << '+'; 106 break; 107 case MCBinaryExpr::And: OS << '&'; break; 108 case MCBinaryExpr::Div: OS << '/'; break; 109 case MCBinaryExpr::EQ: OS << "=="; break; 110 case MCBinaryExpr::GT: OS << '>'; break; 111 case MCBinaryExpr::GTE: OS << ">="; break; 112 case MCBinaryExpr::LAnd: OS << "&&"; break; 113 case MCBinaryExpr::LOr: OS << "||"; break; 114 case MCBinaryExpr::LT: OS << '<'; break; 115 case MCBinaryExpr::LTE: OS << "<="; break; 116 case MCBinaryExpr::Mod: OS << '%'; break; 117 case MCBinaryExpr::Mul: OS << '*'; break; 118 case MCBinaryExpr::NE: OS << "!="; break; 119 case MCBinaryExpr::Or: OS << '|'; break; 120 case MCBinaryExpr::Shl: OS << "<<"; break; 121 case MCBinaryExpr::Shr: OS << ">>"; break; 122 case MCBinaryExpr::Sub: OS << '-'; break; 123 case MCBinaryExpr::Xor: OS << '^'; break; 124 } 125 126 // Only print parens around the LHS if it is non-trivial. 127 if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) { 128 OS << *BE.getRHS(); 129 } else { 130 OS << '(' << *BE.getRHS() << ')'; 131 } 132 return; 133 } 134 } 135 136 llvm_unreachable("Invalid expression kind!"); 137 } 138 139 void MCExpr::dump() const { 140 print(dbgs()); 141 dbgs() << '\n'; 142 } 143 144 /* *** */ 145 146 const MCBinaryExpr *MCBinaryExpr::Create(Opcode Opc, const MCExpr *LHS, 147 const MCExpr *RHS, MCContext &Ctx) { 148 return new (Ctx) MCBinaryExpr(Opc, LHS, RHS); 149 } 150 151 const MCUnaryExpr *MCUnaryExpr::Create(Opcode Opc, const MCExpr *Expr, 152 MCContext &Ctx) { 153 return new (Ctx) MCUnaryExpr(Opc, Expr); 154 } 155 156 const MCConstantExpr *MCConstantExpr::Create(int64_t Value, MCContext &Ctx) { 157 return new (Ctx) MCConstantExpr(Value); 158 } 159 160 /* *** */ 161 162 const MCSymbolRefExpr *MCSymbolRefExpr::Create(const MCSymbol *Sym, 163 VariantKind Kind, 164 MCContext &Ctx) { 165 return new (Ctx) MCSymbolRefExpr(Sym, Kind); 166 } 167 168 const MCSymbolRefExpr *MCSymbolRefExpr::Create(StringRef Name, VariantKind Kind, 169 MCContext &Ctx) { 170 return Create(Ctx.GetOrCreateSymbol(Name), Kind, Ctx); 171 } 172 173 StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) { 174 switch (Kind) { 175 case VK_Invalid: return "<<invalid>>"; 176 case VK_None: return "<<none>>"; 177 178 case VK_GOT: return "GOT"; 179 case VK_GOTOFF: return "GOTOFF"; 180 case VK_GOTPCREL: return "GOTPCREL"; 181 case VK_GOTTPOFF: return "GOTTPOFF"; 182 case VK_INDNTPOFF: return "INDNTPOFF"; 183 case VK_NTPOFF: return "NTPOFF"; 184 case VK_GOTNTPOFF: return "GOTNTPOFF"; 185 case VK_PLT: return "PLT"; 186 case VK_TLSGD: return "TLSGD"; 187 case VK_TLSLD: return "TLSLD"; 188 case VK_TLSLDM: return "TLSLDM"; 189 case VK_TPOFF: return "TPOFF"; 190 case VK_DTPOFF: return "DTPOFF"; 191 case VK_TLVP: return "TLVP"; 192 case VK_SECREL: return "SECREL"; 193 case VK_ARM_PLT: return "(PLT)"; 194 case VK_ARM_GOT: return "(GOT)"; 195 case VK_ARM_GOTOFF: return "(GOTOFF)"; 196 case VK_ARM_TPOFF: return "(tpoff)"; 197 case VK_ARM_GOTTPOFF: return "(gottpoff)"; 198 case VK_ARM_TLSGD: return "(tlsgd)"; 199 case VK_ARM_TARGET1: return "(target1)"; 200 case VK_PPC_TOC: return "toc"; 201 case VK_PPC_DARWIN_HA16: return "ha16"; 202 case VK_PPC_DARWIN_LO16: return "lo16"; 203 case VK_PPC_GAS_HA16: return "ha"; 204 case VK_PPC_GAS_LO16: return "l"; 205 case VK_Mips_GPREL: return "GPREL"; 206 case VK_Mips_GOT_CALL: return "GOT_CALL"; 207 case VK_Mips_GOT16: return "GOT16"; 208 case VK_Mips_GOT: return "GOT"; 209 case VK_Mips_ABS_HI: return "ABS_HI"; 210 case VK_Mips_ABS_LO: return "ABS_LO"; 211 case VK_Mips_TLSGD: return "TLSGD"; 212 case VK_Mips_TLSLDM: return "TLSLDM"; 213 case VK_Mips_DTPREL_HI: return "DTPREL_HI"; 214 case VK_Mips_DTPREL_LO: return "DTPREL_LO"; 215 case VK_Mips_GOTTPREL: return "GOTTPREL"; 216 case VK_Mips_TPREL_HI: return "TPREL_HI"; 217 case VK_Mips_TPREL_LO: return "TPREL_LO"; 218 case VK_Mips_GPOFF_HI: return "GPOFF_HI"; 219 case VK_Mips_GPOFF_LO: return "GPOFF_LO"; 220 case VK_Mips_GOT_DISP: return "GOT_DISP"; 221 case VK_Mips_GOT_PAGE: return "GOT_PAGE"; 222 case VK_Mips_GOT_OFST: return "GOT_OFST"; 223 } 224 llvm_unreachable("Invalid variant kind"); 225 } 226 227 MCSymbolRefExpr::VariantKind 228 MCSymbolRefExpr::getVariantKindForName(StringRef Name) { 229 return StringSwitch<VariantKind>(Name) 230 .Case("GOT", VK_GOT) 231 .Case("got", VK_GOT) 232 .Case("GOTOFF", VK_GOTOFF) 233 .Case("gotoff", VK_GOTOFF) 234 .Case("GOTPCREL", VK_GOTPCREL) 235 .Case("gotpcrel", VK_GOTPCREL) 236 .Case("GOTTPOFF", VK_GOTTPOFF) 237 .Case("gottpoff", VK_GOTTPOFF) 238 .Case("INDNTPOFF", VK_INDNTPOFF) 239 .Case("indntpoff", VK_INDNTPOFF) 240 .Case("NTPOFF", VK_NTPOFF) 241 .Case("ntpoff", VK_NTPOFF) 242 .Case("GOTNTPOFF", VK_GOTNTPOFF) 243 .Case("gotntpoff", VK_GOTNTPOFF) 244 .Case("PLT", VK_PLT) 245 .Case("plt", VK_PLT) 246 .Case("TLSGD", VK_TLSGD) 247 .Case("tlsgd", VK_TLSGD) 248 .Case("TLSLD", VK_TLSLD) 249 .Case("tlsld", VK_TLSLD) 250 .Case("TLSLDM", VK_TLSLDM) 251 .Case("tlsldm", VK_TLSLDM) 252 .Case("TPOFF", VK_TPOFF) 253 .Case("tpoff", VK_TPOFF) 254 .Case("DTPOFF", VK_DTPOFF) 255 .Case("dtpoff", VK_DTPOFF) 256 .Case("TLVP", VK_TLVP) 257 .Case("tlvp", VK_TLVP) 258 .Default(VK_Invalid); 259 } 260 261 /* *** */ 262 263 void MCTargetExpr::Anchor() {} 264 265 /* *** */ 266 267 bool MCExpr::EvaluateAsAbsolute(int64_t &Res) const { 268 return EvaluateAsAbsolute(Res, 0, 0, 0); 269 } 270 271 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, 272 const MCAsmLayout &Layout) const { 273 return EvaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, 0); 274 } 275 276 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, 277 const MCAsmLayout &Layout, 278 const SectionAddrMap &Addrs) const { 279 return EvaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, &Addrs); 280 } 281 282 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const { 283 return EvaluateAsAbsolute(Res, &Asm, 0, 0); 284 } 285 286 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm, 287 const MCAsmLayout *Layout, 288 const SectionAddrMap *Addrs) const { 289 MCValue Value; 290 291 // Fast path constants. 292 if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) { 293 Res = CE->getValue(); 294 return true; 295 } 296 297 // FIXME: The use if InSet = Addrs is a hack. Setting InSet causes us 298 // absolutize differences across sections and that is what the MachO writer 299 // uses Addrs for. 300 bool IsRelocatable = 301 EvaluateAsRelocatableImpl(Value, Asm, Layout, Addrs, /*InSet*/ Addrs); 302 303 // Record the current value. 304 Res = Value.getConstant(); 305 306 return IsRelocatable && Value.isAbsolute(); 307 } 308 309 /// \brief Helper method for \see EvaluateSymbolAdd(). 310 static void AttemptToFoldSymbolOffsetDifference(const MCAssembler *Asm, 311 const MCAsmLayout *Layout, 312 const SectionAddrMap *Addrs, 313 bool InSet, 314 const MCSymbolRefExpr *&A, 315 const MCSymbolRefExpr *&B, 316 int64_t &Addend) { 317 if (!A || !B) 318 return; 319 320 const MCSymbol &SA = A->getSymbol(); 321 const MCSymbol &SB = B->getSymbol(); 322 323 if (SA.isUndefined() || SB.isUndefined()) 324 return; 325 326 if (!Asm->getWriter().IsSymbolRefDifferenceFullyResolved(*Asm, A, B, InSet)) 327 return; 328 329 MCSymbolData &AD = Asm->getSymbolData(SA); 330 MCSymbolData &BD = Asm->getSymbolData(SB); 331 332 if (AD.getFragment() == BD.getFragment()) { 333 Addend += (AD.getOffset() - BD.getOffset()); 334 335 // Pointers to Thumb symbols need to have their low-bit set to allow 336 // for interworking. 337 if (Asm->isThumbFunc(&SA)) 338 Addend |= 1; 339 340 // Clear the symbol expr pointers to indicate we have folded these 341 // operands. 342 A = B = 0; 343 return; 344 } 345 346 if (!Layout) 347 return; 348 349 const MCSectionData &SecA = *AD.getFragment()->getParent(); 350 const MCSectionData &SecB = *BD.getFragment()->getParent(); 351 352 if ((&SecA != &SecB) && !Addrs) 353 return; 354 355 // Eagerly evaluate. 356 Addend += (Layout->getSymbolOffset(&Asm->getSymbolData(A->getSymbol())) - 357 Layout->getSymbolOffset(&Asm->getSymbolData(B->getSymbol()))); 358 if (Addrs && (&SecA != &SecB)) 359 Addend += (Addrs->lookup(&SecA) - Addrs->lookup(&SecB)); 360 361 // Pointers to Thumb symbols need to have their low-bit set to allow 362 // for interworking. 363 if (Asm->isThumbFunc(&SA)) 364 Addend |= 1; 365 366 // Clear the symbol expr pointers to indicate we have folded these 367 // operands. 368 A = B = 0; 369 } 370 371 /// \brief Evaluate the result of an add between (conceptually) two MCValues. 372 /// 373 /// This routine conceptually attempts to construct an MCValue: 374 /// Result = (Result_A - Result_B + Result_Cst) 375 /// from two MCValue's LHS and RHS where 376 /// Result = LHS + RHS 377 /// and 378 /// Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst). 379 /// 380 /// This routine attempts to aggresively fold the operands such that the result 381 /// is representable in an MCValue, but may not always succeed. 382 /// 383 /// \returns True on success, false if the result is not representable in an 384 /// MCValue. 385 386 /// NOTE: It is really important to have both the Asm and Layout arguments. 387 /// They might look redundant, but this function can be used before layout 388 /// is done (see the object streamer for example) and having the Asm argument 389 /// lets us avoid relaxations early. 390 static bool EvaluateSymbolicAdd(const MCAssembler *Asm, 391 const MCAsmLayout *Layout, 392 const SectionAddrMap *Addrs, 393 bool InSet, 394 const MCValue &LHS,const MCSymbolRefExpr *RHS_A, 395 const MCSymbolRefExpr *RHS_B, int64_t RHS_Cst, 396 MCValue &Res) { 397 // FIXME: This routine (and other evaluation parts) are *incredibly* sloppy 398 // about dealing with modifiers. This will ultimately bite us, one day. 399 const MCSymbolRefExpr *LHS_A = LHS.getSymA(); 400 const MCSymbolRefExpr *LHS_B = LHS.getSymB(); 401 int64_t LHS_Cst = LHS.getConstant(); 402 403 // Fold the result constant immediately. 404 int64_t Result_Cst = LHS_Cst + RHS_Cst; 405 406 assert((!Layout || Asm) && 407 "Must have an assembler object if layout is given!"); 408 409 // If we have a layout, we can fold resolved differences. 410 if (Asm) { 411 // First, fold out any differences which are fully resolved. By 412 // reassociating terms in 413 // Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst). 414 // we have the four possible differences: 415 // (LHS_A - LHS_B), 416 // (LHS_A - RHS_B), 417 // (RHS_A - LHS_B), 418 // (RHS_A - RHS_B). 419 // Since we are attempting to be as aggressive as possible about folding, we 420 // attempt to evaluate each possible alternative. 421 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, LHS_B, 422 Result_Cst); 423 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, RHS_B, 424 Result_Cst); 425 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, LHS_B, 426 Result_Cst); 427 AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, RHS_B, 428 Result_Cst); 429 } 430 431 // We can't represent the addition or subtraction of two symbols. 432 if ((LHS_A && RHS_A) || (LHS_B && RHS_B)) 433 return false; 434 435 // At this point, we have at most one additive symbol and one subtractive 436 // symbol -- find them. 437 const MCSymbolRefExpr *A = LHS_A ? LHS_A : RHS_A; 438 const MCSymbolRefExpr *B = LHS_B ? LHS_B : RHS_B; 439 440 // If we have a negated symbol, then we must have also have a non-negated 441 // symbol in order to encode the expression. 442 if (B && !A) 443 return false; 444 445 Res = MCValue::get(A, B, Result_Cst); 446 return true; 447 } 448 449 bool MCExpr::EvaluateAsRelocatable(MCValue &Res, 450 const MCAsmLayout &Layout) const { 451 return EvaluateAsRelocatableImpl(Res, &Layout.getAssembler(), &Layout, 452 0, false); 453 } 454 455 bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res, 456 const MCAssembler *Asm, 457 const MCAsmLayout *Layout, 458 const SectionAddrMap *Addrs, 459 bool InSet) const { 460 ++stats::MCExprEvaluate; 461 462 switch (getKind()) { 463 case Target: 464 return cast<MCTargetExpr>(this)->EvaluateAsRelocatableImpl(Res, Layout); 465 466 case Constant: 467 Res = MCValue::get(cast<MCConstantExpr>(this)->getValue()); 468 return true; 469 470 case SymbolRef: { 471 const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this); 472 const MCSymbol &Sym = SRE->getSymbol(); 473 474 // Evaluate recursively if this is a variable. 475 if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None) { 476 bool Ret = Sym.getVariableValue()->EvaluateAsRelocatableImpl(Res, Asm, 477 Layout, 478 Addrs, 479 true); 480 // If we failed to simplify this to a constant, let the target 481 // handle it. 482 if (Ret && !Res.getSymA() && !Res.getSymB()) 483 return true; 484 } 485 486 Res = MCValue::get(SRE, 0, 0); 487 return true; 488 } 489 490 case Unary: { 491 const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this); 492 MCValue Value; 493 494 if (!AUE->getSubExpr()->EvaluateAsRelocatableImpl(Value, Asm, Layout, 495 Addrs, InSet)) 496 return false; 497 498 switch (AUE->getOpcode()) { 499 case MCUnaryExpr::LNot: 500 if (!Value.isAbsolute()) 501 return false; 502 Res = MCValue::get(!Value.getConstant()); 503 break; 504 case MCUnaryExpr::Minus: 505 /// -(a - b + const) ==> (b - a - const) 506 if (Value.getSymA() && !Value.getSymB()) 507 return false; 508 Res = MCValue::get(Value.getSymB(), Value.getSymA(), 509 -Value.getConstant()); 510 break; 511 case MCUnaryExpr::Not: 512 if (!Value.isAbsolute()) 513 return false; 514 Res = MCValue::get(~Value.getConstant()); 515 break; 516 case MCUnaryExpr::Plus: 517 Res = Value; 518 break; 519 } 520 521 return true; 522 } 523 524 case Binary: { 525 const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this); 526 MCValue LHSValue, RHSValue; 527 528 if (!ABE->getLHS()->EvaluateAsRelocatableImpl(LHSValue, Asm, Layout, 529 Addrs, InSet) || 530 !ABE->getRHS()->EvaluateAsRelocatableImpl(RHSValue, Asm, Layout, 531 Addrs, InSet)) 532 return false; 533 534 // We only support a few operations on non-constant expressions, handle 535 // those first. 536 if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) { 537 switch (ABE->getOpcode()) { 538 default: 539 return false; 540 case MCBinaryExpr::Sub: 541 // Negate RHS and add. 542 return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue, 543 RHSValue.getSymB(), RHSValue.getSymA(), 544 -RHSValue.getConstant(), 545 Res); 546 547 case MCBinaryExpr::Add: 548 return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue, 549 RHSValue.getSymA(), RHSValue.getSymB(), 550 RHSValue.getConstant(), 551 Res); 552 } 553 } 554 555 // FIXME: We need target hooks for the evaluation. It may be limited in 556 // width, and gas defines the result of comparisons and right shifts 557 // differently from Apple as. 558 int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant(); 559 int64_t Result = 0; 560 switch (ABE->getOpcode()) { 561 case MCBinaryExpr::Add: Result = LHS + RHS; break; 562 case MCBinaryExpr::And: Result = LHS & RHS; break; 563 case MCBinaryExpr::Div: Result = LHS / RHS; break; 564 case MCBinaryExpr::EQ: Result = LHS == RHS; break; 565 case MCBinaryExpr::GT: Result = LHS > RHS; break; 566 case MCBinaryExpr::GTE: Result = LHS >= RHS; break; 567 case MCBinaryExpr::LAnd: Result = LHS && RHS; break; 568 case MCBinaryExpr::LOr: Result = LHS || RHS; break; 569 case MCBinaryExpr::LT: Result = LHS < RHS; break; 570 case MCBinaryExpr::LTE: Result = LHS <= RHS; break; 571 case MCBinaryExpr::Mod: Result = LHS % RHS; break; 572 case MCBinaryExpr::Mul: Result = LHS * RHS; break; 573 case MCBinaryExpr::NE: Result = LHS != RHS; break; 574 case MCBinaryExpr::Or: Result = LHS | RHS; break; 575 case MCBinaryExpr::Shl: Result = LHS << RHS; break; 576 case MCBinaryExpr::Shr: Result = LHS >> RHS; break; 577 case MCBinaryExpr::Sub: Result = LHS - RHS; break; 578 case MCBinaryExpr::Xor: Result = LHS ^ RHS; break; 579 } 580 581 Res = MCValue::get(Result); 582 return true; 583 } 584 } 585 586 llvm_unreachable("Invalid assembly expression kind!"); 587 } 588 589 const MCSection *MCExpr::FindAssociatedSection() const { 590 switch (getKind()) { 591 case Target: 592 // We never look through target specific expressions. 593 return cast<MCTargetExpr>(this)->FindAssociatedSection(); 594 595 case Constant: 596 return MCSymbol::AbsolutePseudoSection; 597 598 case SymbolRef: { 599 const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this); 600 const MCSymbol &Sym = SRE->getSymbol(); 601 602 if (Sym.isDefined()) 603 return &Sym.getSection(); 604 605 return 0; 606 } 607 608 case Unary: 609 return cast<MCUnaryExpr>(this)->getSubExpr()->FindAssociatedSection(); 610 611 case Binary: { 612 const MCBinaryExpr *BE = cast<MCBinaryExpr>(this); 613 const MCSection *LHS_S = BE->getLHS()->FindAssociatedSection(); 614 const MCSection *RHS_S = BE->getRHS()->FindAssociatedSection(); 615 616 // If either section is absolute, return the other. 617 if (LHS_S == MCSymbol::AbsolutePseudoSection) 618 return RHS_S; 619 if (RHS_S == MCSymbol::AbsolutePseudoSection) 620 return LHS_S; 621 622 // Otherwise, return the first non-null section. 623 return LHS_S ? LHS_S : RHS_S; 624 } 625 } 626 627 llvm_unreachable("Invalid assembly expression kind!"); 628 } 629