TargetInfo.cpp revision be4c8705e499b55548467eb7adaa23cbc6edfef9 
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>
20using namespace clang;
21
22// TargetInfo Constructor.
23TargetInfo::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.
70TargetInfo::~TargetInfo() {}
71
72/// getTypeName - Return the user string for the specified integer type enum.
73/// For example, SignedShort -> "short".
74const 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".
90const 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().
106unsigned 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().
122unsigned 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.
138bool 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.
157void TargetInfo::setForcedLangOptions(LangOptions &Opts) {
158  if (Opts.NoBitFieldTypeAlign)
159    UseBitFieldTypeAlignment = false;
160  if (Opts.ShortWChar)
161    WCharType = UnsignedShort;
162}
163
164//===----------------------------------------------------------------------===//
165
166
167static 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.
177bool 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
222llvm::StringRef
223TargetInfo::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
261bool 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
316bool 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
340bool 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}
434