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      1 //===--- TargetInfo.cpp - Information about Target machine ----------------===//
      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 //  This file implements the TargetInfo and TargetInfoImpl interfaces.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "clang/Basic/TargetInfo.h"
     15 #include "clang/Basic/AddressSpaces.h"
     16 #include "clang/Basic/CharInfo.h"
     17 #include "clang/Basic/LangOptions.h"
     18 #include "llvm/ADT/APFloat.h"
     19 #include "llvm/ADT/STLExtras.h"
     20 #include "llvm/Support/ErrorHandling.h"
     21 #include <cstdlib>
     22 using namespace clang;
     23 
     24 static const LangAS::Map DefaultAddrSpaceMap = { 0 };
     25 
     26 // TargetInfo Constructor.
     27 TargetInfo::TargetInfo(const llvm::Triple &T) : TargetOpts(), Triple(T) {
     28   // Set defaults.  Defaults are set for a 32-bit RISC platform, like PPC or
     29   // SPARC.  These should be overridden by concrete targets as needed.
     30   BigEndian = true;
     31   TLSSupported = true;
     32   NoAsmVariants = false;
     33   PointerWidth = PointerAlign = 32;
     34   BoolWidth = BoolAlign = 8;
     35   IntWidth = IntAlign = 32;
     36   LongWidth = LongAlign = 32;
     37   LongLongWidth = LongLongAlign = 64;
     38   SuitableAlign = 64;
     39   MinGlobalAlign = 0;
     40   HalfWidth = 16;
     41   HalfAlign = 16;
     42   FloatWidth = 32;
     43   FloatAlign = 32;
     44   DoubleWidth = 64;
     45   DoubleAlign = 64;
     46   LongDoubleWidth = 64;
     47   LongDoubleAlign = 64;
     48   LargeArrayMinWidth = 0;
     49   LargeArrayAlign = 0;
     50   MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 0;
     51   MaxVectorAlign = 0;
     52   SizeType = UnsignedLong;
     53   PtrDiffType = SignedLong;
     54   IntMaxType = SignedLongLong;
     55   IntPtrType = SignedLong;
     56   WCharType = SignedInt;
     57   WIntType = SignedInt;
     58   Char16Type = UnsignedShort;
     59   Char32Type = UnsignedInt;
     60   Int64Type = SignedLongLong;
     61   SigAtomicType = SignedInt;
     62   ProcessIDType = SignedInt;
     63   UseSignedCharForObjCBool = true;
     64   UseBitFieldTypeAlignment = true;
     65   UseZeroLengthBitfieldAlignment = false;
     66   ZeroLengthBitfieldBoundary = 0;
     67   HalfFormat = &llvm::APFloat::IEEEhalf;
     68   FloatFormat = &llvm::APFloat::IEEEsingle;
     69   DoubleFormat = &llvm::APFloat::IEEEdouble;
     70   LongDoubleFormat = &llvm::APFloat::IEEEdouble;
     71   DescriptionString = nullptr;
     72   UserLabelPrefix = "_";
     73   MCountName = "mcount";
     74   RegParmMax = 0;
     75   SSERegParmMax = 0;
     76   HasAlignMac68kSupport = false;
     77 
     78   // Default to no types using fpret.
     79   RealTypeUsesObjCFPRet = 0;
     80 
     81   // Default to not using fp2ret for __Complex long double
     82   ComplexLongDoubleUsesFP2Ret = false;
     83 
     84   // Set the C++ ABI based on the triple.
     85   TheCXXABI.set(Triple.isKnownWindowsMSVCEnvironment()
     86                     ? TargetCXXABI::Microsoft
     87                     : TargetCXXABI::GenericItanium);
     88 
     89   // Default to an empty address space map.
     90   AddrSpaceMap = &DefaultAddrSpaceMap;
     91   UseAddrSpaceMapMangling = false;
     92 
     93   // Default to an unknown platform name.
     94   PlatformName = "unknown";
     95   PlatformMinVersion = VersionTuple();
     96 }
     97 
     98 // Out of line virtual dtor for TargetInfo.
     99 TargetInfo::~TargetInfo() {}
    100 
    101 /// getTypeName - Return the user string for the specified integer type enum.
    102 /// For example, SignedShort -> "short".
    103 const char *TargetInfo::getTypeName(IntType T) {
    104   switch (T) {
    105   default: llvm_unreachable("not an integer!");
    106   case SignedChar:       return "signed char";
    107   case UnsignedChar:     return "unsigned char";
    108   case SignedShort:      return "short";
    109   case UnsignedShort:    return "unsigned short";
    110   case SignedInt:        return "int";
    111   case UnsignedInt:      return "unsigned int";
    112   case SignedLong:       return "long int";
    113   case UnsignedLong:     return "long unsigned int";
    114   case SignedLongLong:   return "long long int";
    115   case UnsignedLongLong: return "long long unsigned int";
    116   }
    117 }
    118 
    119 /// getTypeConstantSuffix - Return the constant suffix for the specified
    120 /// integer type enum. For example, SignedLong -> "L".
    121 const char *TargetInfo::getTypeConstantSuffix(IntType T) const {
    122   switch (T) {
    123   default: llvm_unreachable("not an integer!");
    124   case SignedChar:
    125   case SignedShort:
    126   case SignedInt:        return "";
    127   case SignedLong:       return "L";
    128   case SignedLongLong:   return "LL";
    129   case UnsignedChar:
    130     if (getCharWidth() < getIntWidth())
    131       return "";
    132   case UnsignedShort:
    133     if (getShortWidth() < getIntWidth())
    134       return "";
    135   case UnsignedInt:      return "U";
    136   case UnsignedLong:     return "UL";
    137   case UnsignedLongLong: return "ULL";
    138   }
    139 }
    140 
    141 /// getTypeFormatModifier - Return the printf format modifier for the
    142 /// specified integer type enum. For example, SignedLong -> "l".
    143 
    144 const char *TargetInfo::getTypeFormatModifier(IntType T) {
    145   switch (T) {
    146   default: llvm_unreachable("not an integer!");
    147   case SignedChar:
    148   case UnsignedChar:     return "hh";
    149   case SignedShort:
    150   case UnsignedShort:    return "h";
    151   case SignedInt:
    152   case UnsignedInt:      return "";
    153   case SignedLong:
    154   case UnsignedLong:     return "l";
    155   case SignedLongLong:
    156   case UnsignedLongLong: return "ll";
    157   }
    158 }
    159 
    160 /// getTypeWidth - Return the width (in bits) of the specified integer type
    161 /// enum. For example, SignedInt -> getIntWidth().
    162 unsigned TargetInfo::getTypeWidth(IntType T) const {
    163   switch (T) {
    164   default: llvm_unreachable("not an integer!");
    165   case SignedChar:
    166   case UnsignedChar:     return getCharWidth();
    167   case SignedShort:
    168   case UnsignedShort:    return getShortWidth();
    169   case SignedInt:
    170   case UnsignedInt:      return getIntWidth();
    171   case SignedLong:
    172   case UnsignedLong:     return getLongWidth();
    173   case SignedLongLong:
    174   case UnsignedLongLong: return getLongLongWidth();
    175   };
    176 }
    177 
    178 TargetInfo::IntType TargetInfo::getIntTypeByWidth(
    179     unsigned BitWidth, bool IsSigned) const {
    180   if (getCharWidth() == BitWidth)
    181     return IsSigned ? SignedChar : UnsignedChar;
    182   if (getShortWidth() == BitWidth)
    183     return IsSigned ? SignedShort : UnsignedShort;
    184   if (getIntWidth() == BitWidth)
    185     return IsSigned ? SignedInt : UnsignedInt;
    186   if (getLongWidth() == BitWidth)
    187     return IsSigned ? SignedLong : UnsignedLong;
    188   if (getLongLongWidth() == BitWidth)
    189     return IsSigned ? SignedLongLong : UnsignedLongLong;
    190   return NoInt;
    191 }
    192 
    193 TargetInfo::IntType TargetInfo::getLeastIntTypeByWidth(unsigned BitWidth,
    194                                                        bool IsSigned) const {
    195   if (getCharWidth() >= BitWidth)
    196     return IsSigned ? SignedChar : UnsignedChar;
    197   if (getShortWidth() >= BitWidth)
    198     return IsSigned ? SignedShort : UnsignedShort;
    199   if (getIntWidth() >= BitWidth)
    200     return IsSigned ? SignedInt : UnsignedInt;
    201   if (getLongWidth() >= BitWidth)
    202     return IsSigned ? SignedLong : UnsignedLong;
    203   if (getLongLongWidth() >= BitWidth)
    204     return IsSigned ? SignedLongLong : UnsignedLongLong;
    205   return NoInt;
    206 }
    207 
    208 TargetInfo::RealType TargetInfo::getRealTypeByWidth(unsigned BitWidth) const {
    209   if (getFloatWidth() == BitWidth)
    210     return Float;
    211   if (getDoubleWidth() == BitWidth)
    212     return Double;
    213 
    214   switch (BitWidth) {
    215   case 96:
    216     if (&getLongDoubleFormat() == &llvm::APFloat::x87DoubleExtended)
    217       return LongDouble;
    218     break;
    219   case 128:
    220     if (&getLongDoubleFormat() == &llvm::APFloat::PPCDoubleDouble ||
    221         &getLongDoubleFormat() == &llvm::APFloat::IEEEquad)
    222       return LongDouble;
    223     break;
    224   }
    225 
    226   return NoFloat;
    227 }
    228 
    229 /// getTypeAlign - Return the alignment (in bits) of the specified integer type
    230 /// enum. For example, SignedInt -> getIntAlign().
    231 unsigned TargetInfo::getTypeAlign(IntType T) const {
    232   switch (T) {
    233   default: llvm_unreachable("not an integer!");
    234   case SignedChar:
    235   case UnsignedChar:     return getCharAlign();
    236   case SignedShort:
    237   case UnsignedShort:    return getShortAlign();
    238   case SignedInt:
    239   case UnsignedInt:      return getIntAlign();
    240   case SignedLong:
    241   case UnsignedLong:     return getLongAlign();
    242   case SignedLongLong:
    243   case UnsignedLongLong: return getLongLongAlign();
    244   };
    245 }
    246 
    247 /// isTypeSigned - Return whether an integer types is signed. Returns true if
    248 /// the type is signed; false otherwise.
    249 bool TargetInfo::isTypeSigned(IntType T) {
    250   switch (T) {
    251   default: llvm_unreachable("not an integer!");
    252   case SignedChar:
    253   case SignedShort:
    254   case SignedInt:
    255   case SignedLong:
    256   case SignedLongLong:
    257     return true;
    258   case UnsignedChar:
    259   case UnsignedShort:
    260   case UnsignedInt:
    261   case UnsignedLong:
    262   case UnsignedLongLong:
    263     return false;
    264   };
    265 }
    266 
    267 /// adjust - Set forced language options.
    268 /// Apply changes to the target information with respect to certain
    269 /// language options which change the target configuration.
    270 void TargetInfo::adjust(const LangOptions &Opts) {
    271   if (Opts.NoBitFieldTypeAlign)
    272     UseBitFieldTypeAlignment = false;
    273   if (Opts.ShortWChar)
    274     WCharType = UnsignedShort;
    275 
    276   if (Opts.OpenCL) {
    277     // OpenCL C requires specific widths for types, irrespective of
    278     // what these normally are for the target.
    279     // We also define long long and long double here, although the
    280     // OpenCL standard only mentions these as "reserved".
    281     IntWidth = IntAlign = 32;
    282     LongWidth = LongAlign = 64;
    283     LongLongWidth = LongLongAlign = 128;
    284     HalfWidth = HalfAlign = 16;
    285     FloatWidth = FloatAlign = 32;
    286 
    287     // Embedded 32-bit targets (OpenCL EP) might have double C type
    288     // defined as float. Let's not override this as it might lead
    289     // to generating illegal code that uses 64bit doubles.
    290     if (DoubleWidth != FloatWidth) {
    291       DoubleWidth = DoubleAlign = 64;
    292       DoubleFormat = &llvm::APFloat::IEEEdouble;
    293     }
    294     LongDoubleWidth = LongDoubleAlign = 128;
    295 
    296     assert(PointerWidth == 32 || PointerWidth == 64);
    297     bool Is32BitArch = PointerWidth == 32;
    298     SizeType = Is32BitArch ? UnsignedInt : UnsignedLong;
    299     PtrDiffType = Is32BitArch ? SignedInt : SignedLong;
    300     IntPtrType = Is32BitArch ? SignedInt : SignedLong;
    301 
    302     IntMaxType = SignedLongLong;
    303     Int64Type = SignedLong;
    304 
    305     HalfFormat = &llvm::APFloat::IEEEhalf;
    306     FloatFormat = &llvm::APFloat::IEEEsingle;
    307     LongDoubleFormat = &llvm::APFloat::IEEEquad;
    308   }
    309 }
    310 
    311 //===----------------------------------------------------------------------===//
    312 
    313 
    314 static StringRef removeGCCRegisterPrefix(StringRef Name) {
    315   if (Name[0] == '%' || Name[0] == '#')
    316     Name = Name.substr(1);
    317 
    318   return Name;
    319 }
    320 
    321 /// isValidClobber - Returns whether the passed in string is
    322 /// a valid clobber in an inline asm statement. This is used by
    323 /// Sema.
    324 bool TargetInfo::isValidClobber(StringRef Name) const {
    325   return (isValidGCCRegisterName(Name) ||
    326 	  Name == "memory" || Name == "cc");
    327 }
    328 
    329 /// isValidGCCRegisterName - Returns whether the passed in string
    330 /// is a valid register name according to GCC. This is used by Sema for
    331 /// inline asm statements.
    332 bool TargetInfo::isValidGCCRegisterName(StringRef Name) const {
    333   if (Name.empty())
    334     return false;
    335 
    336   const char * const *Names;
    337   unsigned NumNames;
    338 
    339   // Get rid of any register prefix.
    340   Name = removeGCCRegisterPrefix(Name);
    341   if (Name.empty())
    342       return false;
    343 
    344   getGCCRegNames(Names, NumNames);
    345 
    346   // If we have a number it maps to an entry in the register name array.
    347   if (isDigit(Name[0])) {
    348     int n;
    349     if (!Name.getAsInteger(0, n))
    350       return n >= 0 && (unsigned)n < NumNames;
    351   }
    352 
    353   // Check register names.
    354   for (unsigned i = 0; i < NumNames; i++) {
    355     if (Name == Names[i])
    356       return true;
    357   }
    358 
    359   // Check any additional names that we have.
    360   const AddlRegName *AddlNames;
    361   unsigned NumAddlNames;
    362   getGCCAddlRegNames(AddlNames, NumAddlNames);
    363   for (unsigned i = 0; i < NumAddlNames; i++)
    364     for (unsigned j = 0; j < llvm::array_lengthof(AddlNames[i].Names); j++) {
    365       if (!AddlNames[i].Names[j])
    366 	break;
    367       // Make sure the register that the additional name is for is within
    368       // the bounds of the register names from above.
    369       if (AddlNames[i].Names[j] == Name && AddlNames[i].RegNum < NumNames)
    370 	return true;
    371   }
    372 
    373   // Now check aliases.
    374   const GCCRegAlias *Aliases;
    375   unsigned NumAliases;
    376 
    377   getGCCRegAliases(Aliases, NumAliases);
    378   for (unsigned i = 0; i < NumAliases; i++) {
    379     for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
    380       if (!Aliases[i].Aliases[j])
    381         break;
    382       if (Aliases[i].Aliases[j] == Name)
    383         return true;
    384     }
    385   }
    386 
    387   return false;
    388 }
    389 
    390 StringRef
    391 TargetInfo::getNormalizedGCCRegisterName(StringRef Name) const {
    392   assert(isValidGCCRegisterName(Name) && "Invalid register passed in");
    393 
    394   // Get rid of any register prefix.
    395   Name = removeGCCRegisterPrefix(Name);
    396 
    397   const char * const *Names;
    398   unsigned NumNames;
    399 
    400   getGCCRegNames(Names, NumNames);
    401 
    402   // First, check if we have a number.
    403   if (isDigit(Name[0])) {
    404     int n;
    405     if (!Name.getAsInteger(0, n)) {
    406       assert(n >= 0 && (unsigned)n < NumNames &&
    407              "Out of bounds register number!");
    408       return Names[n];
    409     }
    410   }
    411 
    412   // Check any additional names that we have.
    413   const AddlRegName *AddlNames;
    414   unsigned NumAddlNames;
    415   getGCCAddlRegNames(AddlNames, NumAddlNames);
    416   for (unsigned i = 0; i < NumAddlNames; i++)
    417     for (unsigned j = 0; j < llvm::array_lengthof(AddlNames[i].Names); j++) {
    418       if (!AddlNames[i].Names[j])
    419 	break;
    420       // Make sure the register that the additional name is for is within
    421       // the bounds of the register names from above.
    422       if (AddlNames[i].Names[j] == Name && AddlNames[i].RegNum < NumNames)
    423 	return Name;
    424     }
    425 
    426   // Now check aliases.
    427   const GCCRegAlias *Aliases;
    428   unsigned NumAliases;
    429 
    430   getGCCRegAliases(Aliases, NumAliases);
    431   for (unsigned i = 0; i < NumAliases; i++) {
    432     for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
    433       if (!Aliases[i].Aliases[j])
    434         break;
    435       if (Aliases[i].Aliases[j] == Name)
    436         return Aliases[i].Register;
    437     }
    438   }
    439 
    440   return Name;
    441 }
    442 
    443 bool TargetInfo::validateOutputConstraint(ConstraintInfo &Info) const {
    444   const char *Name = Info.getConstraintStr().c_str();
    445   // An output constraint must start with '=' or '+'
    446   if (*Name != '=' && *Name != '+')
    447     return false;
    448 
    449   if (*Name == '+')
    450     Info.setIsReadWrite();
    451 
    452   Name++;
    453   while (*Name) {
    454     switch (*Name) {
    455     default:
    456       if (!validateAsmConstraint(Name, Info)) {
    457         // FIXME: We temporarily return false
    458         // so we can add more constraints as we hit it.
    459         // Eventually, an unknown constraint should just be treated as 'g'.
    460         return false;
    461       }
    462       break;
    463     case '&': // early clobber.
    464       Info.setEarlyClobber();
    465       break;
    466     case '%': // commutative.
    467       // FIXME: Check that there is a another register after this one.
    468       break;
    469     case 'r': // general register.
    470       Info.setAllowsRegister();
    471       break;
    472     case 'm': // memory operand.
    473     case 'o': // offsetable memory operand.
    474     case 'V': // non-offsetable memory operand.
    475     case '<': // autodecrement memory operand.
    476     case '>': // autoincrement memory operand.
    477       Info.setAllowsMemory();
    478       break;
    479     case 'g': // general register, memory operand or immediate integer.
    480     case 'X': // any operand.
    481       Info.setAllowsRegister();
    482       Info.setAllowsMemory();
    483       break;
    484     case ',': // multiple alternative constraint.  Pass it.
    485       // Handle additional optional '=' or '+' modifiers.
    486       if (Name[1] == '=' || Name[1] == '+')
    487         Name++;
    488       break;
    489     case '#': // Ignore as constraint.
    490       while (Name[1] && Name[1] != ',')
    491         Name++;
    492       break;
    493     case '?': // Disparage slightly code.
    494     case '!': // Disparage severely.
    495     case '*': // Ignore for choosing register preferences.
    496       break;  // Pass them.
    497     }
    498 
    499     Name++;
    500   }
    501 
    502   // Early clobber with a read-write constraint which doesn't permit registers
    503   // is invalid.
    504   if (Info.earlyClobber() && Info.isReadWrite() && !Info.allowsRegister())
    505     return false;
    506 
    507   // If a constraint allows neither memory nor register operands it contains
    508   // only modifiers. Reject it.
    509   return Info.allowsMemory() || Info.allowsRegister();
    510 }
    511 
    512 bool TargetInfo::resolveSymbolicName(const char *&Name,
    513                                      ConstraintInfo *OutputConstraints,
    514                                      unsigned NumOutputs,
    515                                      unsigned &Index) const {
    516   assert(*Name == '[' && "Symbolic name did not start with '['");
    517   Name++;
    518   const char *Start = Name;
    519   while (*Name && *Name != ']')
    520     Name++;
    521 
    522   if (!*Name) {
    523     // Missing ']'
    524     return false;
    525   }
    526 
    527   std::string SymbolicName(Start, Name - Start);
    528 
    529   for (Index = 0; Index != NumOutputs; ++Index)
    530     if (SymbolicName == OutputConstraints[Index].getName())
    531       return true;
    532 
    533   return false;
    534 }
    535 
    536 bool TargetInfo::validateInputConstraint(ConstraintInfo *OutputConstraints,
    537                                          unsigned NumOutputs,
    538                                          ConstraintInfo &Info) const {
    539   const char *Name = Info.ConstraintStr.c_str();
    540 
    541   if (!*Name)
    542     return false;
    543 
    544   while (*Name) {
    545     switch (*Name) {
    546     default:
    547       // Check if we have a matching constraint
    548       if (*Name >= '0' && *Name <= '9') {
    549         const char *DigitStart = Name;
    550         while (Name[1] >= '0' && Name[1] <= '9')
    551           Name++;
    552         const char *DigitEnd = Name;
    553         unsigned i;
    554         if (StringRef(DigitStart, DigitEnd - DigitStart + 1)
    555                 .getAsInteger(10, i))
    556           return false;
    557 
    558         // Check if matching constraint is out of bounds.
    559         if (i >= NumOutputs) return false;
    560 
    561         // A number must refer to an output only operand.
    562         if (OutputConstraints[i].isReadWrite())
    563           return false;
    564 
    565         // If the constraint is already tied, it must be tied to the
    566         // same operand referenced to by the number.
    567         if (Info.hasTiedOperand() && Info.getTiedOperand() != i)
    568           return false;
    569 
    570         // The constraint should have the same info as the respective
    571         // output constraint.
    572         Info.setTiedOperand(i, OutputConstraints[i]);
    573       } else if (!validateAsmConstraint(Name, Info)) {
    574         // FIXME: This error return is in place temporarily so we can
    575         // add more constraints as we hit it.  Eventually, an unknown
    576         // constraint should just be treated as 'g'.
    577         return false;
    578       }
    579       break;
    580     case '[': {
    581       unsigned Index = 0;
    582       if (!resolveSymbolicName(Name, OutputConstraints, NumOutputs, Index))
    583         return false;
    584 
    585       // If the constraint is already tied, it must be tied to the
    586       // same operand referenced to by the number.
    587       if (Info.hasTiedOperand() && Info.getTiedOperand() != Index)
    588         return false;
    589 
    590       // A number must refer to an output only operand.
    591       if (OutputConstraints[Index].isReadWrite())
    592         return false;
    593 
    594       Info.setTiedOperand(Index, OutputConstraints[Index]);
    595       break;
    596     }
    597     case '%': // commutative
    598       // FIXME: Fail if % is used with the last operand.
    599       break;
    600     case 'i': // immediate integer.
    601     case 'n': // immediate integer with a known value.
    602       break;
    603     case 'I':  // Various constant constraints with target-specific meanings.
    604     case 'J':
    605     case 'K':
    606     case 'L':
    607     case 'M':
    608     case 'N':
    609     case 'O':
    610     case 'P':
    611       if (!validateAsmConstraint(Name, Info))
    612         return false;
    613       break;
    614     case 'r': // general register.
    615       Info.setAllowsRegister();
    616       break;
    617     case 'm': // memory operand.
    618     case 'o': // offsettable memory operand.
    619     case 'V': // non-offsettable memory operand.
    620     case '<': // autodecrement memory operand.
    621     case '>': // autoincrement memory operand.
    622       Info.setAllowsMemory();
    623       break;
    624     case 'g': // general register, memory operand or immediate integer.
    625     case 'X': // any operand.
    626       Info.setAllowsRegister();
    627       Info.setAllowsMemory();
    628       break;
    629     case 'E': // immediate floating point.
    630     case 'F': // immediate floating point.
    631     case 'p': // address operand.
    632       break;
    633     case ',': // multiple alternative constraint.  Ignore comma.
    634       break;
    635     case '#': // Ignore as constraint.
    636       while (Name[1] && Name[1] != ',')
    637         Name++;
    638       break;
    639     case '?': // Disparage slightly code.
    640     case '!': // Disparage severely.
    641     case '*': // Ignore for choosing register preferences.
    642       break;  // Pass them.
    643     }
    644 
    645     Name++;
    646   }
    647 
    648   return true;
    649 }
    650 
    651 bool TargetCXXABI::tryParse(llvm::StringRef name) {
    652   const Kind unknown = static_cast<Kind>(-1);
    653   Kind kind = llvm::StringSwitch<Kind>(name)
    654     .Case("arm", GenericARM)
    655     .Case("ios", iOS)
    656     .Case("itanium", GenericItanium)
    657     .Case("microsoft", Microsoft)
    658     .Case("mips", GenericMIPS)
    659     .Default(unknown);
    660   if (kind == unknown) return false;
    661 
    662   set(kind);
    663   return true;
    664 }
    665