lib/MC/MCExpr.cpp

   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/MCSymbol.h"
  18 #include "llvm/MC/MCValue.h"
  19 #include "llvm/Support/Debug.h"
  20 #include "llvm/Support/raw_ostream.h"
  21 #include "llvm/Target/TargetAsmBackend.h"
  22 using namespace llvm;
  23
  24 namespace {
  25 namespace stats {
  26 STATISTIC(MCExprEvaluate, "Number of MCExpr evaluations");
  27 }
  28 }
  29
  30 void MCExpr::print(raw_ostream &OS) const {
  31   switch (getKind()) {
  32   case MCExpr::Target:
  33     return cast<MCTargetExpr>(this)->PrintImpl(OS);
  34   case MCExpr::Constant:
  35     OS << cast<MCConstantExpr>(*this).getValue();
  36     return;
  37
  38   case MCExpr::SymbolRef: {
  39     const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this);
  40     const MCSymbol &Sym = SRE.getSymbol();
  41     // Parenthesize names that start with $ so that they don't look like
  42     // absolute names.
  43     bool UseParens = Sym.getName()[0] == '$';
  44
  45     if (SRE.getKind() == MCSymbolRefExpr::VK_PPC_HA16 ||
  46         SRE.getKind() == MCSymbolRefExpr::VK_PPC_LO16) {
  47       OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
  48       UseParens = true;
  49     }
  50
  51     if (UseParens)
  52       OS << '(' << Sym << ')';
  53     else
  54       OS << Sym;
  55
  56     if (SRE.getKind() == MCSymbolRefExpr::VK_ARM_PLT ||
  57         SRE.getKind() == MCSymbolRefExpr::VK_ARM_TLSGD ||
  58         SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOT ||
  59         SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTOFF ||
  60         SRE.getKind() == MCSymbolRefExpr::VK_ARM_TPOFF ||
  61         SRE.getKind() == MCSymbolRefExpr::VK_ARM_GOTTPOFF)
  62       OS << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
  63     else if (SRE.getKind() != MCSymbolRefExpr::VK_None &&
  64              SRE.getKind() != MCSymbolRefExpr::VK_PPC_HA16 &&
  65              SRE.getKind() != MCSymbolRefExpr::VK_PPC_LO16)
  66       OS << '@' << MCSymbolRefExpr::getVariantKindName(SRE.getKind());
  67
  68     return;
  69   }
  70
  71   case MCExpr::Unary: {
  72     const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
  73     switch (UE.getOpcode()) {
  74     default: assert(0 && "Invalid opcode!");
  75     case MCUnaryExpr::LNot:  OS << '!'; break;
  76     case MCUnaryExpr::Minus: OS << '-'; break;
  77     case MCUnaryExpr::Not:   OS << '~'; break;
  78     case MCUnaryExpr::Plus:  OS << '+'; break;
  79     }
  80     OS << *UE.getSubExpr();
  81     return;
  82   }
  83
  84   case MCExpr::Binary: {
  85     const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
  86
  87     // Only print parens around the LHS if it is non-trivial.
  88     if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
  89       OS << *BE.getLHS();
  90     } else {
  91       OS << '(' << *BE.getLHS() << ')';
  92     }
  93
  94     switch (BE.getOpcode()) {
  95     default: assert(0 && "Invalid opcode!");
  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   assert(0 && "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   default:
 176   case VK_Invalid: return "<<invalid>>";
 177   case VK_None: return "<<none>>";
 178
 179   case VK_GOT: return "GOT";
 180   case VK_GOTOFF: return "GOTOFF";
 181   case VK_GOTPCREL: return "GOTPCREL";
 182   case VK_GOTTPOFF: return "GOTTPOFF";
 183   case VK_INDNTPOFF: return "INDNTPOFF";
 184   case VK_NTPOFF: return "NTPOFF";
 185   case VK_GOTNTPOFF: return "GOTNTPOFF";
 186   case VK_PLT: return "PLT";
 187   case VK_TLSGD: return "TLSGD";
 188   case VK_TLSLD: return "TLSLD";
 189   case VK_TLSLDM: return "TLSLDM";
 190   case VK_TPOFF: return "TPOFF";
 191   case VK_DTPOFF: return "DTPOFF";
 192   case VK_TLVP: return "TLVP";
 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_PPC_TOC: return "toc";
 200   case VK_PPC_HA16: return "ha16";
 201   case VK_PPC_LO16: return "lo16";
 202   }
 203 }
 204
 205 MCSymbolRefExpr::VariantKind
 206 MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
 207   return StringSwitch<VariantKind>(Name)
 208     .Case("GOT", VK_GOT)
 209     .Case("got", VK_GOT)
 210     .Case("GOTOFF", VK_GOTOFF)
 211     .Case("gotoff", VK_GOTOFF)
 212     .Case("GOTPCREL", VK_GOTPCREL)
 213     .Case("gotpcrel", VK_GOTPCREL)
 214     .Case("GOTTPOFF", VK_GOTTPOFF)
 215     .Case("gottpoff", VK_GOTTPOFF)
 216     .Case("INDNTPOFF", VK_INDNTPOFF)
 217     .Case("indntpoff", VK_INDNTPOFF)
 218     .Case("NTPOFF", VK_NTPOFF)
 219     .Case("ntpoff", VK_NTPOFF)
 220     .Case("GOTNTPOFF", VK_GOTNTPOFF)
 221     .Case("gotntpoff", VK_GOTNTPOFF)
 222     .Case("PLT", VK_PLT)
 223     .Case("plt", VK_PLT)
 224     .Case("TLSGD", VK_TLSGD)
 225     .Case("tlsgd", VK_TLSGD)
 226     .Case("TLSLD", VK_TLSLD)
 227     .Case("tlsld", VK_TLSLD)
 228     .Case("TLSLDM", VK_TLSLDM)
 229     .Case("tlsldm", VK_TLSLDM)
 230     .Case("TPOFF", VK_TPOFF)
 231     .Case("tpoff", VK_TPOFF)
 232     .Case("DTPOFF", VK_DTPOFF)
 233     .Case("dtpoff", VK_DTPOFF)
 234     .Case("TLVP", VK_TLVP)
 235     .Case("tlvp", VK_TLVP)
 236     .Default(VK_Invalid);
 237 }
 238
 239 /* *** */
 240
 241 void MCTargetExpr::Anchor() {}
 242
 243 /* *** */
 244
 245 bool MCExpr::EvaluateAsAbsolute(int64_t &Res) const {
 246   return EvaluateAsAbsolute(Res, 0, 0, 0);
 247 }
 248
 249 bool MCExpr::EvaluateAsAbsolute(int64_t &Res,
 250                                 const MCAsmLayout &Layout) const {
 251   return EvaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, 0);
 252 }
 253
 254 bool MCExpr::EvaluateAsAbsolute(int64_t &Res,
 255                                 const MCAsmLayout &Layout,
 256                                 const SectionAddrMap &Addrs) const {
 257   return EvaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, &Addrs);
 258 }
 259
 260 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const {
 261   return EvaluateAsAbsolute(Res, &Asm, 0, 0);
 262 }
 263
 264 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
 265                                 const MCAsmLayout *Layout,
 266                                 const SectionAddrMap *Addrs) const {
 267   MCValue Value;
 268
 269   // Fast path constants.
 270   if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
 271     Res = CE->getValue();
 272     return true;
 273   }
 274
 275   // FIXME: The use if InSet = Addrs is a hack. Setting InSet causes us
 276   // absolutize differences across sections and that is what the MachO writer
 277   // uses Addrs for.
 278   bool IsRelocatable =
 279     EvaluateAsRelocatableImpl(Value, Asm, Layout, Addrs, /*InSet*/ Addrs);
 280
 281   // Record the current value.
 282   Res = Value.getConstant();
 283
 284   return IsRelocatable && Value.isAbsolute();
 285 }
 286
 287 /// \brief Helper method for \see EvaluateSymbolAdd().
 288 static void AttemptToFoldSymbolOffsetDifference(const MCAssembler *Asm,
 289                                                 const MCAsmLayout *Layout,
 290                                                 const SectionAddrMap *Addrs,
 291                                                 bool InSet,
 292                                                 const MCSymbolRefExpr *&A,
 293                                                 const MCSymbolRefExpr *&B,
 294                                                 int64_t &Addend) {
 295   if (!A || !B)
 296     return;
 297
 298   const MCSymbol &SA = A->getSymbol();
 299   const MCSymbol &SB = B->getSymbol();
 300
 301   if (SA.isUndefined() || SB.isUndefined())
 302     return;
 303
 304   if (!Asm->getWriter().IsSymbolRefDifferenceFullyResolved(*Asm, A, B, InSet))
 305     return;
 306
 307   MCSymbolData &AD = Asm->getSymbolData(SA);
 308   MCSymbolData &BD = Asm->getSymbolData(SB);
 309
 310   if (AD.getFragment() == BD.getFragment()) {
 311     Addend += (AD.getOffset() - BD.getOffset());
 312
 313     // Pointers to Thumb symbols need to have their low-bit set to allow
 314     // for interworking.
 315     if (Asm->isThumbFunc(&SA))
 316       Addend |= 1;
 317
 318     // Clear the symbol expr pointers to indicate we have folded these
 319     // operands.
 320     A = B = 0;
 321     return;
 322   }
 323
 324   if (!Layout)
 325     return;
 326
 327   const MCSectionData &SecA = *AD.getFragment()->getParent();
 328   const MCSectionData &SecB = *BD.getFragment()->getParent();
 329
 330   if ((&SecA != &SecB) && !Addrs)
 331     return;
 332
 333   // Eagerly evaluate.
 334   Addend += (Layout->getSymbolOffset(&Asm->getSymbolData(A->getSymbol())) -
 335              Layout->getSymbolOffset(&Asm->getSymbolData(B->getSymbol())));
 336   if (Addrs && (&SecA != &SecB))
 337     Addend += (Addrs->lookup(&SecA) - Addrs->lookup(&SecB));
 338
 339   // Clear the symbol expr pointers to indicate we have folded these
 340   // operands.
 341   A = B = 0;
 342 }
 343
 344 /// \brief Evaluate the result of an add between (conceptually) two MCValues.
 345 ///
 346 /// This routine conceptually attempts to construct an MCValue:
 347 ///   Result = (Result_A - Result_B + Result_Cst)
 348 /// from two MCValue's LHS and RHS where
 349 ///   Result = LHS + RHS
 350 /// and
 351 ///   Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
 352 ///
 353 /// This routine attempts to aggresively fold the operands such that the result
 354 /// is representable in an MCValue, but may not always succeed.
 355 ///
 356 /// \returns True on success, false if the result is not representable in an
 357 /// MCValue.
 358
 359 /// NOTE: It is really important to have both the Asm and Layout arguments.
 360 /// They might look redundant, but this function can be used before layout
 361 /// is done (see the object streamer for example) and having the Asm argument
 362 /// lets us avoid relaxations early.
 363 static bool EvaluateSymbolicAdd(const MCAssembler *Asm,
 364                                 const MCAsmLayout *Layout,
 365                                 const SectionAddrMap *Addrs,
 366                                 bool InSet,
 367                                 const MCValue &LHS,const MCSymbolRefExpr *RHS_A,
 368                                 const MCSymbolRefExpr *RHS_B, int64_t RHS_Cst,
 369                                 MCValue &Res) {
 370   // FIXME: This routine (and other evaluation parts) are *incredibly* sloppy
 371   // about dealing with modifiers. This will ultimately bite us, one day.
 372   const MCSymbolRefExpr *LHS_A = LHS.getSymA();
 373   const MCSymbolRefExpr *LHS_B = LHS.getSymB();
 374   int64_t LHS_Cst = LHS.getConstant();
 375
 376   // Fold the result constant immediately.
 377   int64_t Result_Cst = LHS_Cst + RHS_Cst;
 378
 379   assert((!Layout || Asm) &&
 380          "Must have an assembler object if layout is given!");
 381
 382   // If we have a layout, we can fold resolved differences.
 383   if (Asm) {
 384     // First, fold out any differences which are fully resolved. By
 385     // reassociating terms in
 386     //   Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
 387     // we have the four possible differences:
 388     //   (LHS_A - LHS_B),
 389     //   (LHS_A - RHS_B),
 390     //   (RHS_A - LHS_B),
 391     //   (RHS_A - RHS_B).
 392     // Since we are attempting to be as aggresive as possible about folding, we
 393     // attempt to evaluate each possible alternative.
 394     AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, LHS_B,
 395                                         Result_Cst);
 396     AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, RHS_B,
 397                                         Result_Cst);
 398     AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, LHS_B,
 399                                         Result_Cst);
 400     AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, RHS_B,
 401                                         Result_Cst);
 402   }
 403
 404   // We can't represent the addition or subtraction of two symbols.
 405   if ((LHS_A && RHS_A) || (LHS_B && RHS_B))
 406     return false;
 407
 408   // At this point, we have at most one additive symbol and one subtractive
 409   // symbol -- find them.
 410   const MCSymbolRefExpr *A = LHS_A ? LHS_A : RHS_A;
 411   const MCSymbolRefExpr *B = LHS_B ? LHS_B : RHS_B;
 412
 413   // If we have a negated symbol, then we must have also have a non-negated
 414   // symbol in order to encode the expression.
 415   if (B && !A)
 416     return false;
 417
 418   Res = MCValue::get(A, B, Result_Cst);
 419   return true;
 420 }
 421
 422 bool MCExpr::EvaluateAsRelocatable(MCValue &Res,
 423                                    const MCAsmLayout &Layout) const {
 424   return EvaluateAsRelocatableImpl(Res, &Layout.getAssembler(), &Layout,
 425                                    0, false);
 426 }
 427
 428 bool MCExpr::EvaluateAsRelocatableImpl(MCValue &Res,
 429                                        const MCAssembler *Asm,
 430                                        const MCAsmLayout *Layout,
 431                                        const SectionAddrMap *Addrs,
 432                                        bool InSet) const {
 433   ++stats::MCExprEvaluate;
 434
 435   switch (getKind()) {
 436   case Target:
 437     return cast<MCTargetExpr>(this)->EvaluateAsRelocatableImpl(Res, Layout);
 438
 439   case Constant:
 440     Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
 441     return true;
 442
 443   case SymbolRef: {
 444     const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
 445     const MCSymbol &Sym = SRE->getSymbol();
 446
 447     // Evaluate recursively if this is a variable.
 448     if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None) {
 449       bool Ret = Sym.getVariableValue()->EvaluateAsRelocatableImpl(Res, Asm,
 450                                                                    Layout,
 451                                                                    Addrs,
 452                                                                    true);
 453       // If we failed to simplify this to a constant, let the target
 454       // handle it.
 455       if (Ret && !Res.getSymA() && !Res.getSymB())
 456         return true;
 457     }
 458
 459     Res = MCValue::get(SRE, 0, 0);
 460     return true;
 461   }
 462
 463   case Unary: {
 464     const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
 465     MCValue Value;
 466
 467     if (!AUE->getSubExpr()->EvaluateAsRelocatableImpl(Value, Asm, Layout,
 468                                                       Addrs, InSet))
 469       return false;
 470
 471     switch (AUE->getOpcode()) {
 472     case MCUnaryExpr::LNot:
 473       if (!Value.isAbsolute())
 474         return false;
 475       Res = MCValue::get(!Value.getConstant());
 476       break;
 477     case MCUnaryExpr::Minus:
 478       /// -(a - b + const) ==> (b - a - const)
 479       if (Value.getSymA() && !Value.getSymB())
 480         return false;
 481       Res = MCValue::get(Value.getSymB(), Value.getSymA(),
 482                          -Value.getConstant());
 483       break;
 484     case MCUnaryExpr::Not:
 485       if (!Value.isAbsolute())
 486         return false;
 487       Res = MCValue::get(~Value.getConstant());
 488       break;
 489     case MCUnaryExpr::Plus:
 490       Res = Value;
 491       break;
 492     }
 493
 494     return true;
 495   }
 496
 497   case Binary: {
 498     const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
 499     MCValue LHSValue, RHSValue;
 500
 501     if (!ABE->getLHS()->EvaluateAsRelocatableImpl(LHSValue, Asm, Layout,
 502                                                   Addrs, InSet) ||
 503         !ABE->getRHS()->EvaluateAsRelocatableImpl(RHSValue, Asm, Layout,
 504                                                   Addrs, InSet))
 505       return false;
 506
 507     // We only support a few operations on non-constant expressions, handle
 508     // those first.
 509     if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
 510       switch (ABE->getOpcode()) {
 511       default:
 512         return false;
 513       case MCBinaryExpr::Sub:
 514         // Negate RHS and add.
 515         return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
 516                                    RHSValue.getSymB(), RHSValue.getSymA(),
 517                                    -RHSValue.getConstant(),
 518                                    Res);
 519
 520       case MCBinaryExpr::Add:
 521         return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
 522                                    RHSValue.getSymA(), RHSValue.getSymB(),
 523                                    RHSValue.getConstant(),
 524                                    Res);
 525       }
 526     }
 527
 528     // FIXME: We need target hooks for the evaluation. It may be limited in
 529     // width, and gas defines the result of comparisons and right shifts
 530     // differently from Apple as.
 531     int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
 532     int64_t Result = 0;
 533     switch (ABE->getOpcode()) {
 534     case MCBinaryExpr::Add:  Result = LHS + RHS; break;
 535     case MCBinaryExpr::And:  Result = LHS & RHS; break;
 536     case MCBinaryExpr::Div:  Result = LHS / RHS; break;
 537     case MCBinaryExpr::EQ:   Result = LHS == RHS; break;
 538     case MCBinaryExpr::GT:   Result = LHS > RHS; break;
 539     case MCBinaryExpr::GTE:  Result = LHS >= RHS; break;
 540     case MCBinaryExpr::LAnd: Result = LHS && RHS; break;
 541     case MCBinaryExpr::LOr:  Result = LHS || RHS; break;
 542     case MCBinaryExpr::LT:   Result = LHS < RHS; break;
 543     case MCBinaryExpr::LTE:  Result = LHS <= RHS; break;
 544     case MCBinaryExpr::Mod:  Result = LHS % RHS; break;
 545     case MCBinaryExpr::Mul:  Result = LHS * RHS; break;
 546     case MCBinaryExpr::NE:   Result = LHS != RHS; break;
 547     case MCBinaryExpr::Or:   Result = LHS | RHS; break;
 548     case MCBinaryExpr::Shl:  Result = LHS << RHS; break;
 549     case MCBinaryExpr::Shr:  Result = LHS >> RHS; break;
 550     case MCBinaryExpr::Sub:  Result = LHS - RHS; break;
 551     case MCBinaryExpr::Xor:  Result = LHS ^ RHS; break;
 552     }
 553
 554     Res = MCValue::get(Result);
 555     return true;
 556   }
 557   }
 558
 559   assert(0 && "Invalid assembly expression kind!");
 560   return false;
 561 }