lib/Basic/TargetInfo.cpp

   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/LangOptions.h"
  16 #include "llvm/ADT/APFloat.h"
  17 #include "llvm/ADT/STLExtras.h"
  18 #include <cctype>
  19 #include <cstdlib>
  20 using namespace clang;
  21
  22 // TargetInfo Constructor.
  23 TargetInfo::TargetInfo(const std::string &T) : Triple(T) {
  24   // Set defaults.  Defaults are set for a 32-bit RISC platform, like PPC or
  25   // SPARC.  These should be overridden by concrete targets as needed.
  26   TLSSupported = true;
  27   NoAsmVariants = false;
  28   PointerWidth = PointerAlign = 32;
  29   BoolWidth = BoolAlign = 8;
  30   IntWidth = IntAlign = 32;
  31   LongWidth = LongAlign = 32;
  32   LongLongWidth = LongLongAlign = 64;
  33   FloatWidth = 32;
  34   FloatAlign = 32;
  35   DoubleWidth = 64;
  36   DoubleAlign = 64;
  37   LongDoubleWidth = 64;
  38   LongDoubleAlign = 64;
  39   LargeArrayMinWidth = 0;
  40   LargeArrayAlign = 0;
  41   SizeType = UnsignedLong;
  42   PtrDiffType = SignedLong;
  43   IntMaxType = SignedLongLong;
  44   UIntMaxType = UnsignedLongLong;
  45   IntPtrType = SignedLong;
  46   WCharType = SignedInt;
  47   WIntType = SignedInt;
  48   Char16Type = UnsignedShort;
  49   Char32Type = UnsignedInt;
  50   Int64Type = SignedLongLong;
  51   SigAtomicType = SignedInt;
  52   UseBitFieldTypeAlignment = true;
  53   FloatFormat = &llvm::APFloat::IEEEsingle;
  54   DoubleFormat = &llvm::APFloat::IEEEdouble;
  55   LongDoubleFormat = &llvm::APFloat::IEEEdouble;
  56   DescriptionString = "E-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-"
  57                       "i64:64:64-f32:32:32-f64:64:64-n32";
  58   UserLabelPrefix = "_";
  59   MCountName = "mcount";
  60   HasAlignMac68kSupport = false;
  61
  62   // Default to no types using fpret.
  63   RealTypeUsesObjCFPRet = 0;
  64
  65   // Default to using the Itanium ABI.
  66   CXXABI = CXXABI_Itanium;
  67 }
  68
  69 // Out of line virtual dtor for TargetInfo.
  70 TargetInfo::~TargetInfo() {}
  71
  72 /// getTypeName - Return the user string for the specified integer type enum.
  73 /// For example, SignedShort -> "short".
  74 const char *TargetInfo::getTypeName(IntType T) {
  75   switch (T) {
  76   default: assert(0 && "not an integer!");
  77   case SignedShort:      return "short";
  78   case UnsignedShort:    return "unsigned short";
  79   case SignedInt:        return "int";
  80   case UnsignedInt:      return "unsigned int";
  81   case SignedLong:       return "long int";
  82   case UnsignedLong:     return "long unsigned int";
  83   case SignedLongLong:   return "long long int";
  84   case UnsignedLongLong: return "long long unsigned int";
  85   }
  86 }
  87
  88 /// getTypeConstantSuffix - Return the constant suffix for the specified
  89 /// integer type enum. For example, SignedLong -> "L".
  90 const char *TargetInfo::getTypeConstantSuffix(IntType T) {
  91   switch (T) {
  92   default: assert(0 && "not an integer!");
  93   case SignedShort:
  94   case SignedInt:        return "";
  95   case SignedLong:       return "L";
  96   case SignedLongLong:   return "LL";
  97   case UnsignedShort:
  98   case UnsignedInt:      return "U";
  99   case UnsignedLong:     return "UL";
 100   case UnsignedLongLong: return "ULL";
 101   }
 102 }
 103
 104 /// getTypeWidth - Return the width (in bits) of the specified integer type
 105 /// enum. For example, SignedInt -> getIntWidth().
 106 unsigned TargetInfo::getTypeWidth(IntType T) const {
 107   switch (T) {
 108   default: assert(0 && "not an integer!");
 109   case SignedShort:
 110   case UnsignedShort:    return getShortWidth();
 111   case SignedInt:
 112   case UnsignedInt:      return getIntWidth();
 113   case SignedLong:
 114   case UnsignedLong:     return getLongWidth();
 115   case SignedLongLong:
 116   case UnsignedLongLong: return getLongLongWidth();
 117   };
 118 }
 119
 120 /// getTypeAlign - Return the alignment (in bits) of the specified integer type
 121 /// enum. For example, SignedInt -> getIntAlign().
 122 unsigned TargetInfo::getTypeAlign(IntType T) const {
 123   switch (T) {
 124   default: assert(0 && "not an integer!");
 125   case SignedShort:
 126   case UnsignedShort:    return getShortAlign();
 127   case SignedInt:
 128   case UnsignedInt:      return getIntAlign();
 129   case SignedLong:
 130   case UnsignedLong:     return getLongAlign();
 131   case SignedLongLong:
 132   case UnsignedLongLong: return getLongLongAlign();
 133   };
 134 }
 135
 136 /// isTypeSigned - Return whether an integer types is signed. Returns true if
 137 /// the type is signed; false otherwise.
 138 bool TargetInfo::isTypeSigned(IntType T) {
 139   switch (T) {
 140   default: assert(0 && "not an integer!");
 141   case SignedShort:
 142   case SignedInt:
 143   case SignedLong:
 144   case SignedLongLong:
 145     return true;
 146   case UnsignedShort:
 147   case UnsignedInt:
 148   case UnsignedLong:
 149   case UnsignedLongLong:
 150     return false;
 151   };
 152 }
 153
 154 /// setForcedLangOptions - Set forced language options.
 155 /// Apply changes to the target information with respect to certain
 156 /// language options which change the target configuration.
 157 void TargetInfo::setForcedLangOptions(LangOptions &Opts) {
 158   if (Opts.NoBitFieldTypeAlign)
 159     UseBitFieldTypeAlignment = false;
 160   if (Opts.ShortWChar)
 161     WCharType = UnsignedShort;
 162 }
 163
 164 //===----------------------------------------------------------------------===//
 165
 166
 167 static llvm::StringRef removeGCCRegisterPrefix(llvm::StringRef Name) {
 168   if (Name[0] == '%' || Name[0] == '#')
 169     Name = Name.substr(1);
 170
 171   return Name;
 172 }
 173
 174 /// isValidGCCRegisterName - Returns whether the passed in string
 175 /// is a valid register name according to GCC. This is used by Sema for
 176 /// inline asm statements.
 177 bool TargetInfo::isValidGCCRegisterName(llvm::StringRef Name) const {
 178   if (Name.empty())
 179     return false;
 180
 181   const char * const *Names;
 182   unsigned NumNames;
 183
 184   // Get rid of any register prefix.
 185   Name = removeGCCRegisterPrefix(Name);
 186
 187   if (Name == "memory" || Name == "cc")
 188     return true;
 189
 190   getGCCRegNames(Names, NumNames);
 191
 192   // If we have a number it maps to an entry in the register name array.
 193   if (isdigit(Name[0])) {
 194     int n;
 195     if (!Name.getAsInteger(0, n))
 196       return n >= 0 && (unsigned)n < NumNames;
 197   }
 198
 199   // Check register names.
 200   for (unsigned i = 0; i < NumNames; i++) {
 201     if (Name == Names[i])
 202       return true;
 203   }
 204
 205   // Now check aliases.
 206   const GCCRegAlias *Aliases;
 207   unsigned NumAliases;
 208
 209   getGCCRegAliases(Aliases, NumAliases);
 210   for (unsigned i = 0; i < NumAliases; i++) {
 211     for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
 212       if (!Aliases[i].Aliases[j])
 213         break;
 214       if (Aliases[i].Aliases[j] == Name)
 215         return true;
 216     }
 217   }
 218
 219   return false;
 220 }
 221
 222 llvm::StringRef
 223 TargetInfo::getNormalizedGCCRegisterName(llvm::StringRef Name) const {
 224   assert(isValidGCCRegisterName(Name) && "Invalid register passed in");
 225
 226   // Get rid of any register prefix.
 227   Name = removeGCCRegisterPrefix(Name);
 228
 229   const char * const *Names;
 230   unsigned NumNames;
 231
 232   getGCCRegNames(Names, NumNames);
 233
 234   // First, check if we have a number.
 235   if (isdigit(Name[0])) {
 236     int n;
 237     if (!Name.getAsInteger(0, n)) {
 238       assert(n >= 0 && (unsigned)n < NumNames &&
 239              "Out of bounds register number!");
 240       return Names[n];
 241     }
 242   }
 243
 244   // Now check aliases.
 245   const GCCRegAlias *Aliases;
 246   unsigned NumAliases;
 247
 248   getGCCRegAliases(Aliases, NumAliases);
 249   for (unsigned i = 0; i < NumAliases; i++) {
 250     for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
 251       if (!Aliases[i].Aliases[j])
 252         break;
 253       if (Aliases[i].Aliases[j] == Name)
 254         return Aliases[i].Register;
 255     }
 256   }
 257
 258   return Name;
 259 }
 260
 261 bool TargetInfo::validateOutputConstraint(ConstraintInfo &Info) const {
 262   const char *Name = Info.getConstraintStr().c_str();
 263   // An output constraint must start with '=' or '+'
 264   if (*Name != '=' && *Name != '+')
 265     return false;
 266
 267   if (*Name == '+')
 268     Info.setIsReadWrite();
 269
 270   Name++;
 271   while (*Name) {
 272     switch (*Name) {
 273     default:
 274       if (!validateAsmConstraint(Name, Info)) {
 275         // FIXME: We temporarily return false
 276         // so we can add more constraints as we hit it.
 277         // Eventually, an unknown constraint should just be treated as 'g'.
 278         return false;
 279       }
 280     case '&': // early clobber.
 281       break;
 282     case '%': // commutative.
 283       // FIXME: Check that there is a another register after this one.
 284       break;
 285     case 'r': // general register.
 286       Info.setAllowsRegister();
 287       break;
 288     case 'm': // memory operand.
 289     case 'o': // offsetable memory operand.
 290     case 'V': // non-offsetable memory operand.
 291     case '<': // autodecrement memory operand.
 292     case '>': // autoincrement memory operand.
 293       Info.setAllowsMemory();
 294       break;
 295     case 'g': // general register, memory operand or immediate integer.
 296     case 'X': // any operand.
 297       Info.setAllowsRegister();
 298       Info.setAllowsMemory();
 299       break;
 300     case ',': // multiple alternative constraint.  Pass it.
 301       // Handle additional optional '=' or '+' modifiers.
 302       if (Name[1] == '=' || Name[1] == '+')
 303         Name++;
 304       break;
 305     case '?': // Disparage slightly code.
 306     case '!': // Disparage severely.
 307       break;  // Pass them.
 308     }
 309
 310     Name++;
 311   }
 312
 313   return true;
 314 }
 315
 316 bool TargetInfo::resolveSymbolicName(const char *&Name,
 317                                      ConstraintInfo *OutputConstraints,
 318                                      unsigned NumOutputs,
 319                                      unsigned &Index) const {
 320   assert(*Name == '[' && "Symbolic name did not start with '['");
 321   Name++;
 322   const char *Start = Name;
 323   while (*Name && *Name != ']')
 324     Name++;
 325
 326   if (!*Name) {
 327     // Missing ']'
 328     return false;
 329   }
 330
 331   std::string SymbolicName(Start, Name - Start);
 332
 333   for (Index = 0; Index != NumOutputs; ++Index)
 334     if (SymbolicName == OutputConstraints[Index].getName())
 335       return true;
 336
 337   return false;
 338 }
 339
 340 bool TargetInfo::validateInputConstraint(ConstraintInfo *OutputConstraints,
 341                                          unsigned NumOutputs,
 342                                          ConstraintInfo &Info) const {
 343   const char *Name = Info.ConstraintStr.c_str();
 344
 345   while (*Name) {
 346     switch (*Name) {
 347     default:
 348       // Check if we have a matching constraint
 349       if (*Name >= '0' && *Name <= '9') {
 350         unsigned i = *Name - '0';
 351
 352         // Check if matching constraint is out of bounds.
 353         if (i >= NumOutputs)
 354           return false;
 355
 356         // A number must refer to an output only operand.
 357         if (OutputConstraints[i].isReadWrite())
 358           return false;
 359
 360         // If the constraint is already tied, it must be tied to the
 361         // same operand referenced to by the number.
 362         if (Info.hasTiedOperand() && Info.getTiedOperand() != i)
 363           return false;
 364
 365         // The constraint should have the same info as the respective
 366         // output constraint.
 367         Info.setTiedOperand(i, OutputConstraints[i]);
 368       } else if (!validateAsmConstraint(Name, Info)) {
 369         // FIXME: This error return is in place temporarily so we can
 370         // add more constraints as we hit it.  Eventually, an unknown
 371         // constraint should just be treated as 'g'.
 372         return false;
 373       }
 374       break;
 375     case '[': {
 376       unsigned Index = 0;
 377       if (!resolveSymbolicName(Name, OutputConstraints, NumOutputs, Index))
 378         return false;
 379
 380       // If the constraint is already tied, it must be tied to the
 381       // same operand referenced to by the number.
 382       if (Info.hasTiedOperand() && Info.getTiedOperand() != Index)
 383         return false;
 384
 385       Info.setTiedOperand(Index, OutputConstraints[Index]);
 386       break;
 387     }
 388     case '%': // commutative
 389       // FIXME: Fail if % is used with the last operand.
 390       break;
 391     case 'i': // immediate integer.
 392     case 'n': // immediate integer with a known value.
 393       break;
 394     case 'I':  // Various constant constraints with target-specific meanings.
 395     case 'J':
 396     case 'K':
 397     case 'L':
 398     case 'M':
 399     case 'N':
 400     case 'O':
 401     case 'P':
 402       break;
 403     case 'r': // general register.
 404       Info.setAllowsRegister();
 405       break;
 406     case 'm': // memory operand.
 407     case 'o': // offsettable memory operand.
 408     case 'V': // non-offsettable memory operand.
 409     case '<': // autodecrement memory operand.
 410     case '>': // autoincrement memory operand.
 411       Info.setAllowsMemory();
 412       break;
 413     case 'g': // general register, memory operand or immediate integer.
 414     case 'X': // any operand.
 415       Info.setAllowsRegister();
 416       Info.setAllowsMemory();
 417       break;
 418     case 'E': // immediate floating point.
 419     case 'F': // immediate floating point.
 420     case 'p': // address operand.
 421       break;
 422     case ',': // multiple alternative constraint.  Ignore comma.
 423       break;
 424     case '?': // Disparage slightly code.
 425     case '!': // Disparage severly.
 426       break;  // Pass them.
 427     }
 428
 429     Name++;
 430   }
 431
 432   return true;
 433 }