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