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      1 //===--- TargetInfo.cpp - Information about Target machine ----------------===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 //
      9 //  This file implements the TargetInfo and TargetInfoImpl interfaces.
     10 //
     11 //===----------------------------------------------------------------------===//
     12 
     13 #include "clang/Basic/TargetInfo.h"
     14 #include "clang/Basic/AddressSpaces.h"
     15 #include "clang/Basic/CharInfo.h"
     16 #include "clang/Basic/Diagnostic.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 "llvm/Support/TargetParser.h"
     22 #include <cstdlib>
     23 using namespace clang;
     24 
     25 static const LangASMap DefaultAddrSpaceMap = {0};
     26 
     27 // TargetInfo Constructor.
     28 TargetInfo::TargetInfo(const llvm::Triple &T) : TargetOpts(), Triple(T) {
     29   // Set defaults.  Defaults are set for a 32-bit RISC platform, like PPC or
     30   // SPARC.  These should be overridden by concrete targets as needed.
     31   BigEndian = !T.isLittleEndian();
     32   TLSSupported = true;
     33   VLASupported = true;
     34   NoAsmVariants = false;
     35   HasLegalHalfType = false;
     36   HasFloat128 = false;
     37   HasFloat16 = false;
     38   HasBFloat16 = false;
     39   HasStrictFP = false;
     40   PointerWidth = PointerAlign = 32;
     41   BoolWidth = BoolAlign = 8;
     42   IntWidth = IntAlign = 32;
     43   LongWidth = LongAlign = 32;
     44   LongLongWidth = LongLongAlign = 64;
     45 
     46   // Fixed point default bit widths
     47   ShortAccumWidth = ShortAccumAlign = 16;
     48   AccumWidth = AccumAlign = 32;
     49   LongAccumWidth = LongAccumAlign = 64;
     50   ShortFractWidth = ShortFractAlign = 8;
     51   FractWidth = FractAlign = 16;
     52   LongFractWidth = LongFractAlign = 32;
     53 
     54   // Fixed point default integral and fractional bit sizes
     55   // We give the _Accum 1 fewer fractional bits than their corresponding _Fract
     56   // types by default to have the same number of fractional bits between _Accum
     57   // and _Fract types.
     58   PaddingOnUnsignedFixedPoint = false;
     59   ShortAccumScale = 7;
     60   AccumScale = 15;
     61   LongAccumScale = 31;
     62 
     63   SuitableAlign = 64;
     64   DefaultAlignForAttributeAligned = 128;
     65   MinGlobalAlign = 0;
     66   // From the glibc documentation, on GNU systems, malloc guarantees 16-byte
     67   // alignment on 64-bit systems and 8-byte alignment on 32-bit systems. See
     68   // https://www.gnu.org/software/libc/manual/html_node/Malloc-Examples.html.
     69   // This alignment guarantee also applies to Windows and Android. On Darwin,
     70   // the alignment is 16 bytes on both 64-bit and 32-bit systems.
     71   if (T.isGNUEnvironment() || T.isWindowsMSVCEnvironment() || T.isAndroid())
     72     NewAlign = Triple.isArch64Bit() ? 128 : Triple.isArch32Bit() ? 64 : 0;
     73   else if (T.isOSDarwin())
     74     NewAlign = 128;
     75   else
     76     NewAlign = 0; // Infer from basic type alignment.
     77   HalfWidth = 16;
     78   HalfAlign = 16;
     79   FloatWidth = 32;
     80   FloatAlign = 32;
     81   DoubleWidth = 64;
     82   DoubleAlign = 64;
     83   LongDoubleWidth = 64;
     84   LongDoubleAlign = 64;
     85   Float128Align = 128;
     86   LargeArrayMinWidth = 0;
     87   LargeArrayAlign = 0;
     88   MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 0;
     89   MaxVectorAlign = 0;
     90   MaxTLSAlign = 0;
     91   SimdDefaultAlign = 0;
     92   SizeType = UnsignedLong;
     93   PtrDiffType = SignedLong;
     94   IntMaxType = SignedLongLong;
     95   IntPtrType = SignedLong;
     96   WCharType = SignedInt;
     97   WIntType = SignedInt;
     98   Char16Type = UnsignedShort;
     99   Char32Type = UnsignedInt;
    100   Int64Type = SignedLongLong;
    101   Int16Type = SignedShort;
    102   SigAtomicType = SignedInt;
    103   ProcessIDType = SignedInt;
    104   UseSignedCharForObjCBool = true;
    105   UseBitFieldTypeAlignment = true;
    106   UseZeroLengthBitfieldAlignment = false;
    107   UseLeadingZeroLengthBitfield = true;
    108   UseExplicitBitFieldAlignment = true;
    109   ZeroLengthBitfieldBoundary = 0;
    110   MaxAlignedAttribute = 0;
    111   HalfFormat = &llvm::APFloat::IEEEhalf();
    112   FloatFormat = &llvm::APFloat::IEEEsingle();
    113   DoubleFormat = &llvm::APFloat::IEEEdouble();
    114   LongDoubleFormat = &llvm::APFloat::IEEEdouble();
    115   Float128Format = &llvm::APFloat::IEEEquad();
    116   MCountName = "mcount";
    117   UserLabelPrefix = "_";
    118   RegParmMax = 0;
    119   SSERegParmMax = 0;
    120   HasAlignMac68kSupport = false;
    121   HasBuiltinMSVaList = false;
    122   IsRenderScriptTarget = false;
    123   HasAArch64SVETypes = false;
    124   HasRISCVVTypes = false;
    125   AllowAMDGPUUnsafeFPAtomics = false;
    126   ARMCDECoprocMask = 0;
    127 
    128   // Default to no types using fpret.
    129   RealTypeUsesObjCFPRet = 0;
    130 
    131   // Default to not using fp2ret for __Complex long double
    132   ComplexLongDoubleUsesFP2Ret = false;
    133 
    134   // Set the C++ ABI based on the triple.
    135   TheCXXABI.set(Triple.isKnownWindowsMSVCEnvironment()
    136                     ? TargetCXXABI::Microsoft
    137                     : TargetCXXABI::GenericItanium);
    138 
    139   // Default to an empty address space map.
    140   AddrSpaceMap = &DefaultAddrSpaceMap;
    141   UseAddrSpaceMapMangling = false;
    142 
    143   // Default to an unknown platform name.
    144   PlatformName = "unknown";
    145   PlatformMinVersion = VersionTuple();
    146 
    147   MaxOpenCLWorkGroupSize = 1024;
    148 }
    149 
    150 // Out of line virtual dtor for TargetInfo.
    151 TargetInfo::~TargetInfo() {}
    152 
    153 void TargetInfo::resetDataLayout(StringRef DL, const char *ULP) {
    154   DataLayoutString = DL.str();
    155   UserLabelPrefix = ULP;
    156 }
    157 
    158 bool
    159 TargetInfo::checkCFProtectionBranchSupported(DiagnosticsEngine &Diags) const {
    160   Diags.Report(diag::err_opt_not_valid_on_target) << "cf-protection=branch";
    161   return false;
    162 }
    163 
    164 bool
    165 TargetInfo::checkCFProtectionReturnSupported(DiagnosticsEngine &Diags) const {
    166   Diags.Report(diag::err_opt_not_valid_on_target) << "cf-protection=return";
    167   return false;
    168 }
    169 
    170 /// getTypeName - Return the user string for the specified integer type enum.
    171 /// For example, SignedShort -> "short".
    172 const char *TargetInfo::getTypeName(IntType T) {
    173   switch (T) {
    174   default: llvm_unreachable("not an integer!");
    175   case SignedChar:       return "signed char";
    176   case UnsignedChar:     return "unsigned char";
    177   case SignedShort:      return "short";
    178   case UnsignedShort:    return "unsigned short";
    179   case SignedInt:        return "int";
    180   case UnsignedInt:      return "unsigned int";
    181   case SignedLong:       return "long int";
    182   case UnsignedLong:     return "long unsigned int";
    183   case SignedLongLong:   return "long long int";
    184   case UnsignedLongLong: return "long long unsigned int";
    185   }
    186 }
    187 
    188 /// getTypeConstantSuffix - Return the constant suffix for the specified
    189 /// integer type enum. For example, SignedLong -> "L".
    190 const char *TargetInfo::getTypeConstantSuffix(IntType T) const {
    191   switch (T) {
    192   default: llvm_unreachable("not an integer!");
    193   case SignedChar:
    194   case SignedShort:
    195   case SignedInt:        return "";
    196   case SignedLong:       return "L";
    197   case SignedLongLong:   return "LL";
    198   case UnsignedChar:
    199     if (getCharWidth() < getIntWidth())
    200       return "";
    201     LLVM_FALLTHROUGH;
    202   case UnsignedShort:
    203     if (getShortWidth() < getIntWidth())
    204       return "";
    205     LLVM_FALLTHROUGH;
    206   case UnsignedInt:      return "U";
    207   case UnsignedLong:     return "UL";
    208   case UnsignedLongLong: return "ULL";
    209   }
    210 }
    211 
    212 /// getTypeFormatModifier - Return the printf format modifier for the
    213 /// specified integer type enum. For example, SignedLong -> "l".
    214 
    215 const char *TargetInfo::getTypeFormatModifier(IntType T) {
    216   switch (T) {
    217   default: llvm_unreachable("not an integer!");
    218   case SignedChar:
    219   case UnsignedChar:     return "hh";
    220   case SignedShort:
    221   case UnsignedShort:    return "h";
    222   case SignedInt:
    223   case UnsignedInt:      return "";
    224   case SignedLong:
    225   case UnsignedLong:     return "l";
    226   case SignedLongLong:
    227   case UnsignedLongLong: return "ll";
    228   }
    229 }
    230 
    231 /// getTypeWidth - Return the width (in bits) of the specified integer type
    232 /// enum. For example, SignedInt -> getIntWidth().
    233 unsigned TargetInfo::getTypeWidth(IntType T) const {
    234   switch (T) {
    235   default: llvm_unreachable("not an integer!");
    236   case SignedChar:
    237   case UnsignedChar:     return getCharWidth();
    238   case SignedShort:
    239   case UnsignedShort:    return getShortWidth();
    240   case SignedInt:
    241   case UnsignedInt:      return getIntWidth();
    242   case SignedLong:
    243   case UnsignedLong:     return getLongWidth();
    244   case SignedLongLong:
    245   case UnsignedLongLong: return getLongLongWidth();
    246   };
    247 }
    248 
    249 TargetInfo::IntType TargetInfo::getIntTypeByWidth(
    250     unsigned BitWidth, bool IsSigned) const {
    251   if (getCharWidth() == BitWidth)
    252     return IsSigned ? SignedChar : UnsignedChar;
    253   if (getShortWidth() == BitWidth)
    254     return IsSigned ? SignedShort : UnsignedShort;
    255   if (getIntWidth() == BitWidth)
    256     return IsSigned ? SignedInt : UnsignedInt;
    257   if (getLongWidth() == BitWidth)
    258     return IsSigned ? SignedLong : UnsignedLong;
    259   if (getLongLongWidth() == BitWidth)
    260     return IsSigned ? SignedLongLong : UnsignedLongLong;
    261   return NoInt;
    262 }
    263 
    264 TargetInfo::IntType TargetInfo::getLeastIntTypeByWidth(unsigned BitWidth,
    265                                                        bool IsSigned) const {
    266   if (getCharWidth() >= BitWidth)
    267     return IsSigned ? SignedChar : UnsignedChar;
    268   if (getShortWidth() >= BitWidth)
    269     return IsSigned ? SignedShort : UnsignedShort;
    270   if (getIntWidth() >= BitWidth)
    271     return IsSigned ? SignedInt : UnsignedInt;
    272   if (getLongWidth() >= BitWidth)
    273     return IsSigned ? SignedLong : UnsignedLong;
    274   if (getLongLongWidth() >= BitWidth)
    275     return IsSigned ? SignedLongLong : UnsignedLongLong;
    276   return NoInt;
    277 }
    278 
    279 TargetInfo::RealType TargetInfo::getRealTypeByWidth(unsigned BitWidth,
    280                                                     bool ExplicitIEEE) const {
    281   if (getFloatWidth() == BitWidth)
    282     return Float;
    283   if (getDoubleWidth() == BitWidth)
    284     return Double;
    285 
    286   switch (BitWidth) {
    287   case 96:
    288     if (&getLongDoubleFormat() == &llvm::APFloat::x87DoubleExtended())
    289       return LongDouble;
    290     break;
    291   case 128:
    292     // The caller explicitly asked for an IEEE compliant type but we still
    293     // have to check if the target supports it.
    294     if (ExplicitIEEE)
    295       return hasFloat128Type() ? Float128 : NoFloat;
    296     if (&getLongDoubleFormat() == &llvm::APFloat::PPCDoubleDouble() ||
    297         &getLongDoubleFormat() == &llvm::APFloat::IEEEquad())
    298       return LongDouble;
    299     if (hasFloat128Type())
    300       return Float128;
    301     break;
    302   }
    303 
    304   return NoFloat;
    305 }
    306 
    307 /// getTypeAlign - Return the alignment (in bits) of the specified integer type
    308 /// enum. For example, SignedInt -> getIntAlign().
    309 unsigned TargetInfo::getTypeAlign(IntType T) const {
    310   switch (T) {
    311   default: llvm_unreachable("not an integer!");
    312   case SignedChar:
    313   case UnsignedChar:     return getCharAlign();
    314   case SignedShort:
    315   case UnsignedShort:    return getShortAlign();
    316   case SignedInt:
    317   case UnsignedInt:      return getIntAlign();
    318   case SignedLong:
    319   case UnsignedLong:     return getLongAlign();
    320   case SignedLongLong:
    321   case UnsignedLongLong: return getLongLongAlign();
    322   };
    323 }
    324 
    325 /// isTypeSigned - Return whether an integer types is signed. Returns true if
    326 /// the type is signed; false otherwise.
    327 bool TargetInfo::isTypeSigned(IntType T) {
    328   switch (T) {
    329   default: llvm_unreachable("not an integer!");
    330   case SignedChar:
    331   case SignedShort:
    332   case SignedInt:
    333   case SignedLong:
    334   case SignedLongLong:
    335     return true;
    336   case UnsignedChar:
    337   case UnsignedShort:
    338   case UnsignedInt:
    339   case UnsignedLong:
    340   case UnsignedLongLong:
    341     return false;
    342   };
    343 }
    344 
    345 /// adjust - Set forced language options.
    346 /// Apply changes to the target information with respect to certain
    347 /// language options which change the target configuration and adjust
    348 /// the language based on the target options where applicable.
    349 void TargetInfo::adjust(LangOptions &Opts) {
    350   if (Opts.NoBitFieldTypeAlign)
    351     UseBitFieldTypeAlignment = false;
    352 
    353   switch (Opts.WCharSize) {
    354   default: llvm_unreachable("invalid wchar_t width");
    355   case 0: break;
    356   case 1: WCharType = Opts.WCharIsSigned ? SignedChar : UnsignedChar; break;
    357   case 2: WCharType = Opts.WCharIsSigned ? SignedShort : UnsignedShort; break;
    358   case 4: WCharType = Opts.WCharIsSigned ? SignedInt : UnsignedInt; break;
    359   }
    360 
    361   if (Opts.AlignDouble) {
    362     DoubleAlign = LongLongAlign = 64;
    363     LongDoubleAlign = 64;
    364   }
    365 
    366   if (Opts.OpenCL) {
    367     // OpenCL C requires specific widths for types, irrespective of
    368     // what these normally are for the target.
    369     // We also define long long and long double here, although the
    370     // OpenCL standard only mentions these as "reserved".
    371     IntWidth = IntAlign = 32;
    372     LongWidth = LongAlign = 64;
    373     LongLongWidth = LongLongAlign = 128;
    374     HalfWidth = HalfAlign = 16;
    375     FloatWidth = FloatAlign = 32;
    376 
    377     // Embedded 32-bit targets (OpenCL EP) might have double C type
    378     // defined as float. Let's not override this as it might lead
    379     // to generating illegal code that uses 64bit doubles.
    380     if (DoubleWidth != FloatWidth) {
    381       DoubleWidth = DoubleAlign = 64;
    382       DoubleFormat = &llvm::APFloat::IEEEdouble();
    383     }
    384     LongDoubleWidth = LongDoubleAlign = 128;
    385 
    386     unsigned MaxPointerWidth = getMaxPointerWidth();
    387     assert(MaxPointerWidth == 32 || MaxPointerWidth == 64);
    388     bool Is32BitArch = MaxPointerWidth == 32;
    389     SizeType = Is32BitArch ? UnsignedInt : UnsignedLong;
    390     PtrDiffType = Is32BitArch ? SignedInt : SignedLong;
    391     IntPtrType = Is32BitArch ? SignedInt : SignedLong;
    392 
    393     IntMaxType = SignedLongLong;
    394     Int64Type = SignedLong;
    395 
    396     HalfFormat = &llvm::APFloat::IEEEhalf();
    397     FloatFormat = &llvm::APFloat::IEEEsingle();
    398     LongDoubleFormat = &llvm::APFloat::IEEEquad();
    399   }
    400 
    401   if (Opts.DoubleSize) {
    402     if (Opts.DoubleSize == 32) {
    403       DoubleWidth = 32;
    404       LongDoubleWidth = 32;
    405       DoubleFormat = &llvm::APFloat::IEEEsingle();
    406       LongDoubleFormat = &llvm::APFloat::IEEEsingle();
    407     } else if (Opts.DoubleSize == 64) {
    408       DoubleWidth = 64;
    409       LongDoubleWidth = 64;
    410       DoubleFormat = &llvm::APFloat::IEEEdouble();
    411       LongDoubleFormat = &llvm::APFloat::IEEEdouble();
    412     }
    413   }
    414 
    415   if (Opts.LongDoubleSize) {
    416     if (Opts.LongDoubleSize == DoubleWidth) {
    417       LongDoubleWidth = DoubleWidth;
    418       LongDoubleAlign = DoubleAlign;
    419       LongDoubleFormat = DoubleFormat;
    420     } else if (Opts.LongDoubleSize == 128) {
    421       LongDoubleWidth = LongDoubleAlign = 128;
    422       LongDoubleFormat = &llvm::APFloat::IEEEquad();
    423     }
    424   }
    425 
    426   if (Opts.NewAlignOverride)
    427     NewAlign = Opts.NewAlignOverride * getCharWidth();
    428 
    429   // Each unsigned fixed point type has the same number of fractional bits as
    430   // its corresponding signed type.
    431   PaddingOnUnsignedFixedPoint |= Opts.PaddingOnUnsignedFixedPoint;
    432   CheckFixedPointBits();
    433 }
    434 
    435 bool TargetInfo::initFeatureMap(
    436     llvm::StringMap<bool> &Features, DiagnosticsEngine &Diags, StringRef CPU,
    437     const std::vector<std::string> &FeatureVec) const {
    438   for (const auto &F : FeatureVec) {
    439     StringRef Name = F;
    440     // Apply the feature via the target.
    441     bool Enabled = Name[0] == '+';
    442     setFeatureEnabled(Features, Name.substr(1), Enabled);
    443   }
    444   return true;
    445 }
    446 
    447 TargetInfo::CallingConvKind
    448 TargetInfo::getCallingConvKind(bool ClangABICompat4) const {
    449   if (getCXXABI() != TargetCXXABI::Microsoft &&
    450       (ClangABICompat4 || getTriple().getOS() == llvm::Triple::PS4))
    451     return CCK_ClangABI4OrPS4;
    452   return CCK_Default;
    453 }
    454 
    455 LangAS TargetInfo::getOpenCLTypeAddrSpace(OpenCLTypeKind TK) const {
    456   switch (TK) {
    457   case OCLTK_Image:
    458   case OCLTK_Pipe:
    459     return LangAS::opencl_global;
    460 
    461   case OCLTK_Sampler:
    462     return LangAS::opencl_constant;
    463 
    464   default:
    465     return LangAS::Default;
    466   }
    467 }
    468 
    469 //===----------------------------------------------------------------------===//
    470 
    471 
    472 static StringRef removeGCCRegisterPrefix(StringRef Name) {
    473   if (Name[0] == '%' || Name[0] == '#')
    474     Name = Name.substr(1);
    475 
    476   return Name;
    477 }
    478 
    479 /// isValidClobber - Returns whether the passed in string is
    480 /// a valid clobber in an inline asm statement. This is used by
    481 /// Sema.
    482 bool TargetInfo::isValidClobber(StringRef Name) const {
    483   return (isValidGCCRegisterName(Name) || Name == "memory" || Name == "cc" ||
    484           Name == "unwind");
    485 }
    486 
    487 /// isValidGCCRegisterName - Returns whether the passed in string
    488 /// is a valid register name according to GCC. This is used by Sema for
    489 /// inline asm statements.
    490 bool TargetInfo::isValidGCCRegisterName(StringRef Name) const {
    491   if (Name.empty())
    492     return false;
    493 
    494   // Get rid of any register prefix.
    495   Name = removeGCCRegisterPrefix(Name);
    496   if (Name.empty())
    497     return false;
    498 
    499   ArrayRef<const char *> Names = getGCCRegNames();
    500 
    501   // If we have a number it maps to an entry in the register name array.
    502   if (isDigit(Name[0])) {
    503     unsigned n;
    504     if (!Name.getAsInteger(0, n))
    505       return n < Names.size();
    506   }
    507 
    508   // Check register names.
    509   if (llvm::is_contained(Names, Name))
    510     return true;
    511 
    512   // Check any additional names that we have.
    513   for (const AddlRegName &ARN : getGCCAddlRegNames())
    514     for (const char *AN : ARN.Names) {
    515       if (!AN)
    516         break;
    517       // Make sure the register that the additional name is for is within
    518       // the bounds of the register names from above.
    519       if (AN == Name && ARN.RegNum < Names.size())
    520         return true;
    521     }
    522 
    523   // Now check aliases.
    524   for (const GCCRegAlias &GRA : getGCCRegAliases())
    525     for (const char *A : GRA.Aliases) {
    526       if (!A)
    527         break;
    528       if (A == Name)
    529         return true;
    530     }
    531 
    532   return false;
    533 }
    534 
    535 StringRef TargetInfo::getNormalizedGCCRegisterName(StringRef Name,
    536                                                    bool ReturnCanonical) const {
    537   assert(isValidGCCRegisterName(Name) && "Invalid register passed in");
    538 
    539   // Get rid of any register prefix.
    540   Name = removeGCCRegisterPrefix(Name);
    541 
    542   ArrayRef<const char *> Names = getGCCRegNames();
    543 
    544   // First, check if we have a number.
    545   if (isDigit(Name[0])) {
    546     unsigned n;
    547     if (!Name.getAsInteger(0, n)) {
    548       assert(n < Names.size() && "Out of bounds register number!");
    549       return Names[n];
    550     }
    551   }
    552 
    553   // Check any additional names that we have.
    554   for (const AddlRegName &ARN : getGCCAddlRegNames())
    555     for (const char *AN : ARN.Names) {
    556       if (!AN)
    557         break;
    558       // Make sure the register that the additional name is for is within
    559       // the bounds of the register names from above.
    560       if (AN == Name && ARN.RegNum < Names.size())
    561         return ReturnCanonical ? Names[ARN.RegNum] : Name;
    562     }
    563 
    564   // Now check aliases.
    565   for (const GCCRegAlias &RA : getGCCRegAliases())
    566     for (const char *A : RA.Aliases) {
    567       if (!A)
    568         break;
    569       if (A == Name)
    570         return RA.Register;
    571     }
    572 
    573   return Name;
    574 }
    575 
    576 bool TargetInfo::validateOutputConstraint(ConstraintInfo &Info) const {
    577   const char *Name = Info.getConstraintStr().c_str();
    578   // An output constraint must start with '=' or '+'
    579   if (*Name != '=' && *Name != '+')
    580     return false;
    581 
    582   if (*Name == '+')
    583     Info.setIsReadWrite();
    584 
    585   Name++;
    586   while (*Name) {
    587     switch (*Name) {
    588     default:
    589       if (!validateAsmConstraint(Name, Info)) {
    590         // FIXME: We temporarily return false
    591         // so we can add more constraints as we hit it.
    592         // Eventually, an unknown constraint should just be treated as 'g'.
    593         return false;
    594       }
    595       break;
    596     case '&': // early clobber.
    597       Info.setEarlyClobber();
    598       break;
    599     case '%': // commutative.
    600       // FIXME: Check that there is a another register after this one.
    601       break;
    602     case 'r': // general register.
    603       Info.setAllowsRegister();
    604       break;
    605     case 'm': // memory operand.
    606     case 'o': // offsetable memory operand.
    607     case 'V': // non-offsetable memory operand.
    608     case '<': // autodecrement memory operand.
    609     case '>': // autoincrement memory operand.
    610       Info.setAllowsMemory();
    611       break;
    612     case 'g': // general register, memory operand or immediate integer.
    613     case 'X': // any operand.
    614       Info.setAllowsRegister();
    615       Info.setAllowsMemory();
    616       break;
    617     case ',': // multiple alternative constraint.  Pass it.
    618       // Handle additional optional '=' or '+' modifiers.
    619       if (Name[1] == '=' || Name[1] == '+')
    620         Name++;
    621       break;
    622     case '#': // Ignore as constraint.
    623       while (Name[1] && Name[1] != ',')
    624         Name++;
    625       break;
    626     case '?': // Disparage slightly code.
    627     case '!': // Disparage severely.
    628     case '*': // Ignore for choosing register preferences.
    629     case 'i': // Ignore i,n,E,F as output constraints (match from the other
    630               // chars)
    631     case 'n':
    632     case 'E':
    633     case 'F':
    634       break;  // Pass them.
    635     }
    636 
    637     Name++;
    638   }
    639 
    640   // Early clobber with a read-write constraint which doesn't permit registers
    641   // is invalid.
    642   if (Info.earlyClobber() && Info.isReadWrite() && !Info.allowsRegister())
    643     return false;
    644 
    645   // If a constraint allows neither memory nor register operands it contains
    646   // only modifiers. Reject it.
    647   return Info.allowsMemory() || Info.allowsRegister();
    648 }
    649 
    650 bool TargetInfo::resolveSymbolicName(const char *&Name,
    651                                      ArrayRef<ConstraintInfo> OutputConstraints,
    652                                      unsigned &Index) const {
    653   assert(*Name == '[' && "Symbolic name did not start with '['");
    654   Name++;
    655   const char *Start = Name;
    656   while (*Name && *Name != ']')
    657     Name++;
    658 
    659   if (!*Name) {
    660     // Missing ']'
    661     return false;
    662   }
    663 
    664   std::string SymbolicName(Start, Name - Start);
    665 
    666   for (Index = 0; Index != OutputConstraints.size(); ++Index)
    667     if (SymbolicName == OutputConstraints[Index].getName())
    668       return true;
    669 
    670   return false;
    671 }
    672 
    673 bool TargetInfo::validateInputConstraint(
    674                               MutableArrayRef<ConstraintInfo> OutputConstraints,
    675                               ConstraintInfo &Info) const {
    676   const char *Name = Info.ConstraintStr.c_str();
    677 
    678   if (!*Name)
    679     return false;
    680 
    681   while (*Name) {
    682     switch (*Name) {
    683     default:
    684       // Check if we have a matching constraint
    685       if (*Name >= '0' && *Name <= '9') {
    686         const char *DigitStart = Name;
    687         while (Name[1] >= '0' && Name[1] <= '9')
    688           Name++;
    689         const char *DigitEnd = Name;
    690         unsigned i;
    691         if (StringRef(DigitStart, DigitEnd - DigitStart + 1)
    692                 .getAsInteger(10, i))
    693           return false;
    694 
    695         // Check if matching constraint is out of bounds.
    696         if (i >= OutputConstraints.size()) return false;
    697 
    698         // A number must refer to an output only operand.
    699         if (OutputConstraints[i].isReadWrite())
    700           return false;
    701 
    702         // If the constraint is already tied, it must be tied to the
    703         // same operand referenced to by the number.
    704         if (Info.hasTiedOperand() && Info.getTiedOperand() != i)
    705           return false;
    706 
    707         // The constraint should have the same info as the respective
    708         // output constraint.
    709         Info.setTiedOperand(i, OutputConstraints[i]);
    710       } else if (!validateAsmConstraint(Name, Info)) {
    711         // FIXME: This error return is in place temporarily so we can
    712         // add more constraints as we hit it.  Eventually, an unknown
    713         // constraint should just be treated as 'g'.
    714         return false;
    715       }
    716       break;
    717     case '[': {
    718       unsigned Index = 0;
    719       if (!resolveSymbolicName(Name, OutputConstraints, Index))
    720         return false;
    721 
    722       // If the constraint is already tied, it must be tied to the
    723       // same operand referenced to by the number.
    724       if (Info.hasTiedOperand() && Info.getTiedOperand() != Index)
    725         return false;
    726 
    727       // A number must refer to an output only operand.
    728       if (OutputConstraints[Index].isReadWrite())
    729         return false;
    730 
    731       Info.setTiedOperand(Index, OutputConstraints[Index]);
    732       break;
    733     }
    734     case '%': // commutative
    735       // FIXME: Fail if % is used with the last operand.
    736       break;
    737     case 'i': // immediate integer.
    738       break;
    739     case 'n': // immediate integer with a known value.
    740       Info.setRequiresImmediate();
    741       break;
    742     case 'I':  // Various constant constraints with target-specific meanings.
    743     case 'J':
    744     case 'K':
    745     case 'L':
    746     case 'M':
    747     case 'N':
    748     case 'O':
    749     case 'P':
    750       if (!validateAsmConstraint(Name, Info))
    751         return false;
    752       break;
    753     case 'r': // general register.
    754       Info.setAllowsRegister();
    755       break;
    756     case 'm': // memory operand.
    757     case 'o': // offsettable memory operand.
    758     case 'V': // non-offsettable memory operand.
    759     case '<': // autodecrement memory operand.
    760     case '>': // autoincrement memory operand.
    761       Info.setAllowsMemory();
    762       break;
    763     case 'g': // general register, memory operand or immediate integer.
    764     case 'X': // any operand.
    765       Info.setAllowsRegister();
    766       Info.setAllowsMemory();
    767       break;
    768     case 'E': // immediate floating point.
    769     case 'F': // immediate floating point.
    770     case 'p': // address operand.
    771       break;
    772     case ',': // multiple alternative constraint.  Ignore comma.
    773       break;
    774     case '#': // Ignore as constraint.
    775       while (Name[1] && Name[1] != ',')
    776         Name++;
    777       break;
    778     case '?': // Disparage slightly code.
    779     case '!': // Disparage severely.
    780     case '*': // Ignore for choosing register preferences.
    781       break;  // Pass them.
    782     }
    783 
    784     Name++;
    785   }
    786 
    787   return true;
    788 }
    789 
    790 void TargetInfo::CheckFixedPointBits() const {
    791   // Check that the number of fractional and integral bits (and maybe sign) can
    792   // fit into the bits given for a fixed point type.
    793   assert(ShortAccumScale + getShortAccumIBits() + 1 <= ShortAccumWidth);
    794   assert(AccumScale + getAccumIBits() + 1 <= AccumWidth);
    795   assert(LongAccumScale + getLongAccumIBits() + 1 <= LongAccumWidth);
    796   assert(getUnsignedShortAccumScale() + getUnsignedShortAccumIBits() <=
    797          ShortAccumWidth);
    798   assert(getUnsignedAccumScale() + getUnsignedAccumIBits() <= AccumWidth);
    799   assert(getUnsignedLongAccumScale() + getUnsignedLongAccumIBits() <=
    800          LongAccumWidth);
    801 
    802   assert(getShortFractScale() + 1 <= ShortFractWidth);
    803   assert(getFractScale() + 1 <= FractWidth);
    804   assert(getLongFractScale() + 1 <= LongFractWidth);
    805   assert(getUnsignedShortFractScale() <= ShortFractWidth);
    806   assert(getUnsignedFractScale() <= FractWidth);
    807   assert(getUnsignedLongFractScale() <= LongFractWidth);
    808 
    809   // Each unsigned fract type has either the same number of fractional bits
    810   // as, or one more fractional bit than, its corresponding signed fract type.
    811   assert(getShortFractScale() == getUnsignedShortFractScale() ||
    812          getShortFractScale() == getUnsignedShortFractScale() - 1);
    813   assert(getFractScale() == getUnsignedFractScale() ||
    814          getFractScale() == getUnsignedFractScale() - 1);
    815   assert(getLongFractScale() == getUnsignedLongFractScale() ||
    816          getLongFractScale() == getUnsignedLongFractScale() - 1);
    817 
    818   // When arranged in order of increasing rank (see 6.3.1.3a), the number of
    819   // fractional bits is nondecreasing for each of the following sets of
    820   // fixed-point types:
    821   // - signed fract types
    822   // - unsigned fract types
    823   // - signed accum types
    824   // - unsigned accum types.
    825   assert(getLongFractScale() >= getFractScale() &&
    826          getFractScale() >= getShortFractScale());
    827   assert(getUnsignedLongFractScale() >= getUnsignedFractScale() &&
    828          getUnsignedFractScale() >= getUnsignedShortFractScale());
    829   assert(LongAccumScale >= AccumScale && AccumScale >= ShortAccumScale);
    830   assert(getUnsignedLongAccumScale() >= getUnsignedAccumScale() &&
    831          getUnsignedAccumScale() >= getUnsignedShortAccumScale());
    832 
    833   // When arranged in order of increasing rank (see 6.3.1.3a), the number of
    834   // integral bits is nondecreasing for each of the following sets of
    835   // fixed-point types:
    836   // - signed accum types
    837   // - unsigned accum types
    838   assert(getLongAccumIBits() >= getAccumIBits() &&
    839          getAccumIBits() >= getShortAccumIBits());
    840   assert(getUnsignedLongAccumIBits() >= getUnsignedAccumIBits() &&
    841          getUnsignedAccumIBits() >= getUnsignedShortAccumIBits());
    842 
    843   // Each signed accum type has at least as many integral bits as its
    844   // corresponding unsigned accum type.
    845   assert(getShortAccumIBits() >= getUnsignedShortAccumIBits());
    846   assert(getAccumIBits() >= getUnsignedAccumIBits());
    847   assert(getLongAccumIBits() >= getUnsignedLongAccumIBits());
    848 }
    849 
    850 void TargetInfo::copyAuxTarget(const TargetInfo *Aux) {
    851   auto *Target = static_cast<TransferrableTargetInfo*>(this);
    852   auto *Src = static_cast<const TransferrableTargetInfo*>(Aux);
    853   *Target = *Src;
    854 }
    855