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   DefaultAlignForAttributeAligned = 128;
40   MinGlobalAlign = 0;
41   HalfWidth = 16;
42   HalfAlign = 16;
43   FloatWidth = 32;
44   FloatAlign = 32;
45   DoubleWidth = 64;
46   DoubleAlign = 64;
47   LongDoubleWidth = 64;
48   LongDoubleAlign = 64;
49   LargeArrayMinWidth = 0;
50   LargeArrayAlign = 0;
51   MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 0;
52   MaxVectorAlign = 0;
53   SimdDefaultAlign = 0;
54   SizeType = UnsignedLong;
55   PtrDiffType = SignedLong;
56   IntMaxType = SignedLongLong;
57   IntPtrType = SignedLong;
58   WCharType = SignedInt;
59   WIntType = SignedInt;
60   Char16Type = UnsignedShort;
61   Char32Type = UnsignedInt;
62   Int64Type = SignedLongLong;
63   SigAtomicType = SignedInt;
64   ProcessIDType = SignedInt;
65   UseSignedCharForObjCBool = true;
66   UseBitFieldTypeAlignment = true;
67   UseZeroLengthBitfieldAlignment = false;
68   ZeroLengthBitfieldBoundary = 0;
69   HalfFormat = &llvm::APFloat::IEEEhalf;
70   FloatFormat = &llvm::APFloat::IEEEsingle;
71   DoubleFormat = &llvm::APFloat::IEEEdouble;
72   LongDoubleFormat = &llvm::APFloat::IEEEdouble;
73   DescriptionString = nullptr;
74   UserLabelPrefix = "_";
75   MCountName = "mcount";
76   RegParmMax = 0;
77   SSERegParmMax = 0;
78   HasAlignMac68kSupport = false;
79 
80   // Default to no types using fpret.
81   RealTypeUsesObjCFPRet = 0;
82 
83   // Default to not using fp2ret for __Complex long double
84   ComplexLongDoubleUsesFP2Ret = false;
85 
86   // Set the C++ ABI based on the triple.
87   TheCXXABI.set(Triple.isKnownWindowsMSVCEnvironment()
88                     ? TargetCXXABI::Microsoft
89                     : TargetCXXABI::GenericItanium);
90 
91   // Default to an empty address space map.
92   AddrSpaceMap = &DefaultAddrSpaceMap;
93   UseAddrSpaceMapMangling = false;
94 
95   // Default to an unknown platform name.
96   PlatformName = "unknown";
97   PlatformMinVersion = VersionTuple();
98 }
99 
100 // Out of line virtual dtor for TargetInfo.
101 TargetInfo::~TargetInfo() {}
102 
103 /// getTypeName - Return the user string for the specified integer type enum.
104 /// For example, SignedShort -> "short".
105 const char *TargetInfo::getTypeName(IntType T) {
106   switch (T) {
107   default: llvm_unreachable("not an integer!");
108   case SignedChar:       return "signed char";
109   case UnsignedChar:     return "unsigned char";
110   case SignedShort:      return "short";
111   case UnsignedShort:    return "unsigned short";
112   case SignedInt:        return "int";
113   case UnsignedInt:      return "unsigned int";
114   case SignedLong:       return "long int";
115   case UnsignedLong:     return "long unsigned int";
116   case SignedLongLong:   return "long long int";
117   case UnsignedLongLong: return "long long unsigned int";
118   }
119 }
120 
121 /// getTypeConstantSuffix - Return the constant suffix for the specified
122 /// integer type enum. For example, SignedLong -> "L".
123 const char *TargetInfo::getTypeConstantSuffix(IntType T) const {
124   switch (T) {
125   default: llvm_unreachable("not an integer!");
126   case SignedChar:
127   case SignedShort:
128   case SignedInt:        return "";
129   case SignedLong:       return "L";
130   case SignedLongLong:   return "LL";
131   case UnsignedChar:
132     if (getCharWidth() < getIntWidth())
133       return "";
134   case UnsignedShort:
135     if (getShortWidth() < getIntWidth())
136       return "";
137   case UnsignedInt:      return "U";
138   case UnsignedLong:     return "UL";
139   case UnsignedLongLong: return "ULL";
140   }
141 }
142 
143 /// getTypeFormatModifier - Return the printf format modifier for the
144 /// specified integer type enum. For example, SignedLong -> "l".
145 
146 const char *TargetInfo::getTypeFormatModifier(IntType T) {
147   switch (T) {
148   default: llvm_unreachable("not an integer!");
149   case SignedChar:
150   case UnsignedChar:     return "hh";
151   case SignedShort:
152   case UnsignedShort:    return "h";
153   case SignedInt:
154   case UnsignedInt:      return "";
155   case SignedLong:
156   case UnsignedLong:     return "l";
157   case SignedLongLong:
158   case UnsignedLongLong: return "ll";
159   }
160 }
161 
162 /// getTypeWidth - Return the width (in bits) of the specified integer type
163 /// enum. For example, SignedInt -> getIntWidth().
164 unsigned TargetInfo::getTypeWidth(IntType T) const {
165   switch (T) {
166   default: llvm_unreachable("not an integer!");
167   case SignedChar:
168   case UnsignedChar:     return getCharWidth();
169   case SignedShort:
170   case UnsignedShort:    return getShortWidth();
171   case SignedInt:
172   case UnsignedInt:      return getIntWidth();
173   case SignedLong:
174   case UnsignedLong:     return getLongWidth();
175   case SignedLongLong:
176   case UnsignedLongLong: return getLongLongWidth();
177   };
178 }
179 
180 TargetInfo::IntType TargetInfo::getIntTypeByWidth(
181     unsigned BitWidth, bool IsSigned) const {
182   if (getCharWidth() == BitWidth)
183     return IsSigned ? SignedChar : UnsignedChar;
184   if (getShortWidth() == BitWidth)
185     return IsSigned ? SignedShort : UnsignedShort;
186   if (getIntWidth() == BitWidth)
187     return IsSigned ? SignedInt : UnsignedInt;
188   if (getLongWidth() == BitWidth)
189     return IsSigned ? SignedLong : UnsignedLong;
190   if (getLongLongWidth() == BitWidth)
191     return IsSigned ? SignedLongLong : UnsignedLongLong;
192   return NoInt;
193 }
194 
195 TargetInfo::IntType TargetInfo::getLeastIntTypeByWidth(unsigned BitWidth,
196                                                        bool IsSigned) const {
197   if (getCharWidth() >= BitWidth)
198     return IsSigned ? SignedChar : UnsignedChar;
199   if (getShortWidth() >= BitWidth)
200     return IsSigned ? SignedShort : UnsignedShort;
201   if (getIntWidth() >= BitWidth)
202     return IsSigned ? SignedInt : UnsignedInt;
203   if (getLongWidth() >= BitWidth)
204     return IsSigned ? SignedLong : UnsignedLong;
205   if (getLongLongWidth() >= BitWidth)
206     return IsSigned ? SignedLongLong : UnsignedLongLong;
207   return NoInt;
208 }
209 
210 TargetInfo::RealType TargetInfo::getRealTypeByWidth(unsigned BitWidth) const {
211   if (getFloatWidth() == BitWidth)
212     return Float;
213   if (getDoubleWidth() == BitWidth)
214     return Double;
215 
216   switch (BitWidth) {
217   case 96:
218     if (&getLongDoubleFormat() == &llvm::APFloat::x87DoubleExtended)
219       return LongDouble;
220     break;
221   case 128:
222     if (&getLongDoubleFormat() == &llvm::APFloat::PPCDoubleDouble ||
223         &getLongDoubleFormat() == &llvm::APFloat::IEEEquad)
224       return LongDouble;
225     break;
226   }
227 
228   return NoFloat;
229 }
230 
231 /// getTypeAlign - Return the alignment (in bits) of the specified integer type
232 /// enum. For example, SignedInt -> getIntAlign().
233 unsigned TargetInfo::getTypeAlign(IntType T) const {
234   switch (T) {
235   default: llvm_unreachable("not an integer!");
236   case SignedChar:
237   case UnsignedChar:     return getCharAlign();
238   case SignedShort:
239   case UnsignedShort:    return getShortAlign();
240   case SignedInt:
241   case UnsignedInt:      return getIntAlign();
242   case SignedLong:
243   case UnsignedLong:     return getLongAlign();
244   case SignedLongLong:
245   case UnsignedLongLong: return getLongLongAlign();
246   };
247 }
248 
249 /// isTypeSigned - Return whether an integer types is signed. Returns true if
250 /// the type is signed; false otherwise.
251 bool TargetInfo::isTypeSigned(IntType T) {
252   switch (T) {
253   default: llvm_unreachable("not an integer!");
254   case SignedChar:
255   case SignedShort:
256   case SignedInt:
257   case SignedLong:
258   case SignedLongLong:
259     return true;
260   case UnsignedChar:
261   case UnsignedShort:
262   case UnsignedInt:
263   case UnsignedLong:
264   case UnsignedLongLong:
265     return false;
266   };
267 }
268 
269 /// adjust - Set forced language options.
270 /// Apply changes to the target information with respect to certain
271 /// language options which change the target configuration.
272 void TargetInfo::adjust(const LangOptions &Opts) {
273   if (Opts.NoBitFieldTypeAlign)
274     UseBitFieldTypeAlignment = false;
275   if (Opts.ShortWChar)
276     WCharType = UnsignedShort;
277 
278   if (Opts.OpenCL) {
279     // OpenCL C requires specific widths for types, irrespective of
280     // what these normally are for the target.
281     // We also define long long and long double here, although the
282     // OpenCL standard only mentions these as "reserved".
283     IntWidth = IntAlign = 32;
284     LongWidth = LongAlign = 64;
285     LongLongWidth = LongLongAlign = 128;
286     HalfWidth = HalfAlign = 16;
287     FloatWidth = FloatAlign = 32;
288 
289     // Embedded 32-bit targets (OpenCL EP) might have double C type
290     // defined as float. Let's not override this as it might lead
291     // to generating illegal code that uses 64bit doubles.
292     if (DoubleWidth != FloatWidth) {
293       DoubleWidth = DoubleAlign = 64;
294       DoubleFormat = &llvm::APFloat::IEEEdouble;
295     }
296     LongDoubleWidth = LongDoubleAlign = 128;
297 
298     assert(PointerWidth == 32 || PointerWidth == 64);
299     bool Is32BitArch = PointerWidth == 32;
300     SizeType = Is32BitArch ? UnsignedInt : UnsignedLong;
301     PtrDiffType = Is32BitArch ? SignedInt : SignedLong;
302     IntPtrType = Is32BitArch ? SignedInt : SignedLong;
303 
304     IntMaxType = SignedLongLong;
305     Int64Type = SignedLong;
306 
307     HalfFormat = &llvm::APFloat::IEEEhalf;
308     FloatFormat = &llvm::APFloat::IEEEsingle;
309     LongDoubleFormat = &llvm::APFloat::IEEEquad;
310   }
311 }
312 
313 //===----------------------------------------------------------------------===//
314 
315 
316 static StringRef removeGCCRegisterPrefix(StringRef Name) {
317   if (Name[0] == '%' || Name[0] == '#')
318     Name = Name.substr(1);
319 
320   return Name;
321 }
322 
323 /// isValidClobber - Returns whether the passed in string is
324 /// a valid clobber in an inline asm statement. This is used by
325 /// Sema.
326 bool TargetInfo::isValidClobber(StringRef Name) const {
327   return (isValidGCCRegisterName(Name) ||
328 	  Name == "memory" || Name == "cc");
329 }
330 
331 /// isValidGCCRegisterName - Returns whether the passed in string
332 /// is a valid register name according to GCC. This is used by Sema for
333 /// inline asm statements.
334 bool TargetInfo::isValidGCCRegisterName(StringRef Name) const {
335   if (Name.empty())
336     return false;
337 
338   const char * const *Names;
339   unsigned NumNames;
340 
341   // Get rid of any register prefix.
342   Name = removeGCCRegisterPrefix(Name);
343   if (Name.empty())
344       return false;
345 
346   getGCCRegNames(Names, NumNames);
347 
348   // If we have a number it maps to an entry in the register name array.
349   if (isDigit(Name[0])) {
350     int n;
351     if (!Name.getAsInteger(0, n))
352       return n >= 0 && (unsigned)n < NumNames;
353   }
354 
355   // Check register names.
356   for (unsigned i = 0; i < NumNames; i++) {
357     if (Name == Names[i])
358       return true;
359   }
360 
361   // Check any additional names that we have.
362   const AddlRegName *AddlNames;
363   unsigned NumAddlNames;
364   getGCCAddlRegNames(AddlNames, NumAddlNames);
365   for (unsigned i = 0; i < NumAddlNames; i++)
366     for (unsigned j = 0; j < llvm::array_lengthof(AddlNames[i].Names); j++) {
367       if (!AddlNames[i].Names[j])
368 	break;
369       // Make sure the register that the additional name is for is within
370       // the bounds of the register names from above.
371       if (AddlNames[i].Names[j] == Name && AddlNames[i].RegNum < NumNames)
372 	return true;
373   }
374 
375   // Now check aliases.
376   const GCCRegAlias *Aliases;
377   unsigned NumAliases;
378 
379   getGCCRegAliases(Aliases, NumAliases);
380   for (unsigned i = 0; i < NumAliases; i++) {
381     for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
382       if (!Aliases[i].Aliases[j])
383         break;
384       if (Aliases[i].Aliases[j] == Name)
385         return true;
386     }
387   }
388 
389   return false;
390 }
391 
392 StringRef
393 TargetInfo::getNormalizedGCCRegisterName(StringRef Name) const {
394   assert(isValidGCCRegisterName(Name) && "Invalid register passed in");
395 
396   // Get rid of any register prefix.
397   Name = removeGCCRegisterPrefix(Name);
398 
399   const char * const *Names;
400   unsigned NumNames;
401 
402   getGCCRegNames(Names, NumNames);
403 
404   // First, check if we have a number.
405   if (isDigit(Name[0])) {
406     int n;
407     if (!Name.getAsInteger(0, n)) {
408       assert(n >= 0 && (unsigned)n < NumNames &&
409              "Out of bounds register number!");
410       return Names[n];
411     }
412   }
413 
414   // Check any additional names that we have.
415   const AddlRegName *AddlNames;
416   unsigned NumAddlNames;
417   getGCCAddlRegNames(AddlNames, NumAddlNames);
418   for (unsigned i = 0; i < NumAddlNames; i++)
419     for (unsigned j = 0; j < llvm::array_lengthof(AddlNames[i].Names); j++) {
420       if (!AddlNames[i].Names[j])
421 	break;
422       // Make sure the register that the additional name is for is within
423       // the bounds of the register names from above.
424       if (AddlNames[i].Names[j] == Name && AddlNames[i].RegNum < NumNames)
425 	return Name;
426     }
427 
428   // Now check aliases.
429   const GCCRegAlias *Aliases;
430   unsigned NumAliases;
431 
432   getGCCRegAliases(Aliases, NumAliases);
433   for (unsigned i = 0; i < NumAliases; i++) {
434     for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
435       if (!Aliases[i].Aliases[j])
436         break;
437       if (Aliases[i].Aliases[j] == Name)
438         return Aliases[i].Register;
439     }
440   }
441 
442   return Name;
443 }
444 
445 bool TargetInfo::validateOutputConstraint(ConstraintInfo &Info) const {
446   const char *Name = Info.getConstraintStr().c_str();
447   // An output constraint must start with '=' or '+'
448   if (*Name != '=' && *Name != '+')
449     return false;
450 
451   if (*Name == '+')
452     Info.setIsReadWrite();
453 
454   Name++;
455   while (*Name) {
456     switch (*Name) {
457     default:
458       if (!validateAsmConstraint(Name, Info)) {
459         // FIXME: We temporarily return false
460         // so we can add more constraints as we hit it.
461         // Eventually, an unknown constraint should just be treated as 'g'.
462         return false;
463       }
464       break;
465     case '&': // early clobber.
466       Info.setEarlyClobber();
467       break;
468     case '%': // commutative.
469       // FIXME: Check that there is a another register after this one.
470       break;
471     case 'r': // general register.
472       Info.setAllowsRegister();
473       break;
474     case 'm': // memory operand.
475     case 'o': // offsetable memory operand.
476     case 'V': // non-offsetable memory operand.
477     case '<': // autodecrement memory operand.
478     case '>': // autoincrement memory operand.
479       Info.setAllowsMemory();
480       break;
481     case 'g': // general register, memory operand or immediate integer.
482     case 'X': // any operand.
483       Info.setAllowsRegister();
484       Info.setAllowsMemory();
485       break;
486     case ',': // multiple alternative constraint.  Pass it.
487       // Handle additional optional '=' or '+' modifiers.
488       if (Name[1] == '=' || Name[1] == '+')
489         Name++;
490       break;
491     case '#': // Ignore as constraint.
492       while (Name[1] && Name[1] != ',')
493         Name++;
494       break;
495     case '?': // Disparage slightly code.
496     case '!': // Disparage severely.
497     case '*': // Ignore for choosing register preferences.
498       break;  // Pass them.
499     }
500 
501     Name++;
502   }
503 
504   // Early clobber with a read-write constraint which doesn't permit registers
505   // is invalid.
506   if (Info.earlyClobber() && Info.isReadWrite() && !Info.allowsRegister())
507     return false;
508 
509   // If a constraint allows neither memory nor register operands it contains
510   // only modifiers. Reject it.
511   return Info.allowsMemory() || Info.allowsRegister();
512 }
513 
514 bool TargetInfo::resolveSymbolicName(const char *&Name,
515                                      ConstraintInfo *OutputConstraints,
516                                      unsigned NumOutputs,
517                                      unsigned &Index) const {
518   assert(*Name == '[' && "Symbolic name did not start with '['");
519   Name++;
520   const char *Start = Name;
521   while (*Name && *Name != ']')
522     Name++;
523 
524   if (!*Name) {
525     // Missing ']'
526     return false;
527   }
528 
529   std::string SymbolicName(Start, Name - Start);
530 
531   for (Index = 0; Index != NumOutputs; ++Index)
532     if (SymbolicName == OutputConstraints[Index].getName())
533       return true;
534 
535   return false;
536 }
537 
538 bool TargetInfo::validateInputConstraint(ConstraintInfo *OutputConstraints,
539                                          unsigned NumOutputs,
540                                          ConstraintInfo &Info) const {
541   const char *Name = Info.ConstraintStr.c_str();
542 
543   if (!*Name)
544     return false;
545 
546   while (*Name) {
547     switch (*Name) {
548     default:
549       // Check if we have a matching constraint
550       if (*Name >= '0' && *Name <= '9') {
551         const char *DigitStart = Name;
552         while (Name[1] >= '0' && Name[1] <= '9')
553           Name++;
554         const char *DigitEnd = Name;
555         unsigned i;
556         if (StringRef(DigitStart, DigitEnd - DigitStart + 1)
557                 .getAsInteger(10, i))
558           return false;
559 
560         // Check if matching constraint is out of bounds.
561         if (i >= NumOutputs) return false;
562 
563         // A number must refer to an output only operand.
564         if (OutputConstraints[i].isReadWrite())
565           return false;
566 
567         // If the constraint is already tied, it must be tied to the
568         // same operand referenced to by the number.
569         if (Info.hasTiedOperand() && Info.getTiedOperand() != i)
570           return false;
571 
572         // The constraint should have the same info as the respective
573         // output constraint.
574         Info.setTiedOperand(i, OutputConstraints[i]);
575       } else if (!validateAsmConstraint(Name, Info)) {
576         // FIXME: This error return is in place temporarily so we can
577         // add more constraints as we hit it.  Eventually, an unknown
578         // constraint should just be treated as 'g'.
579         return false;
580       }
581       break;
582     case '[': {
583       unsigned Index = 0;
584       if (!resolveSymbolicName(Name, OutputConstraints, NumOutputs, Index))
585         return false;
586 
587       // If the constraint is already tied, it must be tied to the
588       // same operand referenced to by the number.
589       if (Info.hasTiedOperand() && Info.getTiedOperand() != Index)
590         return false;
591 
592       // A number must refer to an output only operand.
593       if (OutputConstraints[Index].isReadWrite())
594         return false;
595 
596       Info.setTiedOperand(Index, OutputConstraints[Index]);
597       break;
598     }
599     case '%': // commutative
600       // FIXME: Fail if % is used with the last operand.
601       break;
602     case 'i': // immediate integer.
603     case 'n': // immediate integer with a known value.
604       break;
605     case 'I':  // Various constant constraints with target-specific meanings.
606     case 'J':
607     case 'K':
608     case 'L':
609     case 'M':
610     case 'N':
611     case 'O':
612     case 'P':
613       if (!validateAsmConstraint(Name, Info))
614         return false;
615       break;
616     case 'r': // general register.
617       Info.setAllowsRegister();
618       break;
619     case 'm': // memory operand.
620     case 'o': // offsettable memory operand.
621     case 'V': // non-offsettable memory operand.
622     case '<': // autodecrement memory operand.
623     case '>': // autoincrement memory operand.
624       Info.setAllowsMemory();
625       break;
626     case 'g': // general register, memory operand or immediate integer.
627     case 'X': // any operand.
628       Info.setAllowsRegister();
629       Info.setAllowsMemory();
630       break;
631     case 'E': // immediate floating point.
632     case 'F': // immediate floating point.
633     case 'p': // address operand.
634       break;
635     case ',': // multiple alternative constraint.  Ignore comma.
636       break;
637     case '#': // Ignore as constraint.
638       while (Name[1] && Name[1] != ',')
639         Name++;
640       break;
641     case '?': // Disparage slightly code.
642     case '!': // Disparage severely.
643     case '*': // Ignore for choosing register preferences.
644       break;  // Pass them.
645     }
646 
647     Name++;
648   }
649 
650   return true;
651 }
652 
653 bool TargetCXXABI::tryParse(llvm::StringRef name) {
654   const Kind unknown = static_cast<Kind>(-1);
655   Kind kind = llvm::StringSwitch<Kind>(name)
656     .Case("arm", GenericARM)
657     .Case("ios", iOS)
658     .Case("itanium", GenericItanium)
659     .Case("microsoft", Microsoft)
660     .Case("mips", GenericMIPS)
661     .Default(unknown);
662   if (kind == unknown) return false;
663 
664   set(kind);
665   return true;
666 }
667