TargetInfo.cpp revision 208600 
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 <cstdlib>
19using namespace clang;
20
21// TargetInfo Constructor.
22TargetInfo::TargetInfo(const std::string &T) : Triple(T) {
23  // Set defaults.  Defaults are set for a 32-bit RISC platform, like PPC or
24  // SPARC.  These should be overridden by concrete targets as needed.
25  TLSSupported = true;
26  NoAsmVariants = false;
27  PointerWidth = PointerAlign = 32;
28  IntWidth = IntAlign = 32;
29  LongWidth = LongAlign = 32;
30  LongLongWidth = LongLongAlign = 64;
31  FloatWidth = 32;
32  FloatAlign = 32;
33  DoubleWidth = 64;
34  DoubleAlign = 64;
35  LongDoubleWidth = 64;
36  LongDoubleAlign = 64;
37  SizeType = UnsignedLong;
38  PtrDiffType = SignedLong;
39  IntMaxType = SignedLongLong;
40  UIntMaxType = UnsignedLongLong;
41  IntPtrType = SignedLong;
42  WCharType = SignedInt;
43  WIntType = SignedInt;
44  Char16Type = UnsignedShort;
45  Char32Type = UnsignedInt;
46  Int64Type = SignedLongLong;
47  SigAtomicType = SignedInt;
48  UseBitFieldTypeAlignment = true;
49  FloatFormat = &llvm::APFloat::IEEEsingle;
50  DoubleFormat = &llvm::APFloat::IEEEdouble;
51  LongDoubleFormat = &llvm::APFloat::IEEEdouble;
52  DescriptionString = "E-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-"
53                      "i64:64:64-f32:32:32-f64:64:64-n32";
54  UserLabelPrefix = "_";
55  HasAlignMac68kSupport = false;
56}
57
58// Out of line virtual dtor for TargetInfo.
59TargetInfo::~TargetInfo() {}
60
61/// getTypeName - Return the user string for the specified integer type enum.
62/// For example, SignedShort -> "short".
63const char *TargetInfo::getTypeName(IntType T) {
64  switch (T) {
65  default: assert(0 && "not an integer!");
66  case SignedShort:      return "short";
67  case UnsignedShort:    return "unsigned short";
68  case SignedInt:        return "int";
69  case UnsignedInt:      return "unsigned int";
70  case SignedLong:       return "long int";
71  case UnsignedLong:     return "long unsigned int";
72  case SignedLongLong:   return "long long int";
73  case UnsignedLongLong: return "long long unsigned int";
74  }
75}
76
77/// getTypeConstantSuffix - Return the constant suffix for the specified
78/// integer type enum. For example, SignedLong -> "L".
79const char *TargetInfo::getTypeConstantSuffix(IntType T) {
80  switch (T) {
81  default: assert(0 && "not an integer!");
82  case SignedShort:
83  case SignedInt:        return "";
84  case SignedLong:       return "L";
85  case SignedLongLong:   return "LL";
86  case UnsignedShort:
87  case UnsignedInt:      return "U";
88  case UnsignedLong:     return "UL";
89  case UnsignedLongLong: return "ULL";
90  }
91}
92
93/// getTypeWidth - Return the width (in bits) of the specified integer type
94/// enum. For example, SignedInt -> getIntWidth().
95unsigned TargetInfo::getTypeWidth(IntType T) const {
96  switch (T) {
97  default: assert(0 && "not an integer!");
98  case SignedShort:
99  case UnsignedShort:    return getShortWidth();
100  case SignedInt:
101  case UnsignedInt:      return getIntWidth();
102  case SignedLong:
103  case UnsignedLong:     return getLongWidth();
104  case SignedLongLong:
105  case UnsignedLongLong: return getLongLongWidth();
106  };
107}
108
109/// getTypeAlign - Return the alignment (in bits) of the specified integer type
110/// enum. For example, SignedInt -> getIntAlign().
111unsigned TargetInfo::getTypeAlign(IntType T) const {
112  switch (T) {
113  default: assert(0 && "not an integer!");
114  case SignedShort:
115  case UnsignedShort:    return getShortAlign();
116  case SignedInt:
117  case UnsignedInt:      return getIntAlign();
118  case SignedLong:
119  case UnsignedLong:     return getLongAlign();
120  case SignedLongLong:
121  case UnsignedLongLong: return getLongLongAlign();
122  };
123}
124
125/// isTypeSigned - Return whether an integer types is signed. Returns true if
126/// the type is signed; false otherwise.
127bool TargetInfo::isTypeSigned(IntType T) const {
128  switch (T) {
129  default: assert(0 && "not an integer!");
130  case SignedShort:
131  case SignedInt:
132  case SignedLong:
133  case SignedLongLong:
134    return true;
135  case UnsignedShort:
136  case UnsignedInt:
137  case UnsignedLong:
138  case UnsignedLongLong:
139    return false;
140  };
141}
142
143/// setForcedLangOptions - Set forced language options.
144/// Apply changes to the target information with respect to certain
145/// language options which change the target configuration.
146void TargetInfo::setForcedLangOptions(LangOptions &Opts) {
147  if (Opts.NoBitFieldTypeAlign)
148    UseBitFieldTypeAlignment = false;
149  if (Opts.ShortWChar)
150    WCharType = UnsignedShort;
151}
152
153//===----------------------------------------------------------------------===//
154
155
156static llvm::StringRef removeGCCRegisterPrefix(llvm::StringRef Name) {
157  if (Name[0] == '%' || Name[0] == '#')
158    Name = Name.substr(1);
159
160  return Name;
161}
162
163/// isValidGCCRegisterName - Returns whether the passed in string
164/// is a valid register name according to GCC. This is used by Sema for
165/// inline asm statements.
166bool TargetInfo::isValidGCCRegisterName(llvm::StringRef Name) const {
167  if (Name.empty())
168    return false;
169
170  const char * const *Names;
171  unsigned NumNames;
172
173  // Get rid of any register prefix.
174  Name = removeGCCRegisterPrefix(Name);
175
176  if (Name == "memory" || Name == "cc")
177    return true;
178
179  getGCCRegNames(Names, NumNames);
180
181  // If we have a number it maps to an entry in the register name array.
182  if (isdigit(Name[0])) {
183    int n;
184    if (!Name.getAsInteger(0, n))
185      return n >= 0 && (unsigned)n < NumNames;
186  }
187
188  // Check register names.
189  for (unsigned i = 0; i < NumNames; i++) {
190    if (Name == Names[i])
191      return true;
192  }
193
194  // Now check aliases.
195  const GCCRegAlias *Aliases;
196  unsigned NumAliases;
197
198  getGCCRegAliases(Aliases, NumAliases);
199  for (unsigned i = 0; i < NumAliases; i++) {
200    for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
201      if (!Aliases[i].Aliases[j])
202        break;
203      if (Aliases[i].Aliases[j] == Name)
204        return true;
205    }
206  }
207
208  return false;
209}
210
211llvm::StringRef
212TargetInfo::getNormalizedGCCRegisterName(llvm::StringRef Name) const {
213  assert(isValidGCCRegisterName(Name) && "Invalid register passed in");
214
215  // Get rid of any register prefix.
216  Name = removeGCCRegisterPrefix(Name);
217
218  const char * const *Names;
219  unsigned NumNames;
220
221  getGCCRegNames(Names, NumNames);
222
223  // First, check if we have a number.
224  if (isdigit(Name[0])) {
225    int n;
226    if (!Name.getAsInteger(0, n)) {
227      assert(n >= 0 && (unsigned)n < NumNames &&
228             "Out of bounds register number!");
229      return Names[n];
230    }
231  }
232
233  // Now check aliases.
234  const GCCRegAlias *Aliases;
235  unsigned NumAliases;
236
237  getGCCRegAliases(Aliases, NumAliases);
238  for (unsigned i = 0; i < NumAliases; i++) {
239    for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
240      if (!Aliases[i].Aliases[j])
241        break;
242      if (Aliases[i].Aliases[j] == Name)
243        return Aliases[i].Register;
244    }
245  }
246
247  return Name;
248}
249
250bool TargetInfo::validateOutputConstraint(ConstraintInfo &Info) const {
251  const char *Name = Info.getConstraintStr().c_str();
252  // An output constraint must start with '=' or '+'
253  if (*Name != '=' && *Name != '+')
254    return false;
255
256  if (*Name == '+')
257    Info.setIsReadWrite();
258
259  Name++;
260  while (*Name) {
261    switch (*Name) {
262    default:
263      if (!validateAsmConstraint(Name, Info)) {
264        // FIXME: We temporarily return false
265        // so we can add more constraints as we hit it.
266        // Eventually, an unknown constraint should just be treated as 'g'.
267        return false;
268      }
269    case '&': // early clobber.
270      break;
271    case '%': // commutative.
272      // FIXME: Check that there is a another register after this one.
273      break;
274    case 'r': // general register.
275      Info.setAllowsRegister();
276      break;
277    case 'm': // memory operand.
278      Info.setAllowsMemory();
279      break;
280    case 'g': // general register, memory operand or immediate integer.
281    case 'X': // any operand.
282      Info.setAllowsRegister();
283      Info.setAllowsMemory();
284      break;
285    }
286
287    Name++;
288  }
289
290  return true;
291}
292
293bool TargetInfo::resolveSymbolicName(const char *&Name,
294                                     ConstraintInfo *OutputConstraints,
295                                     unsigned NumOutputs,
296                                     unsigned &Index) const {
297  assert(*Name == '[' && "Symbolic name did not start with '['");
298  Name++;
299  const char *Start = Name;
300  while (*Name && *Name != ']')
301    Name++;
302
303  if (!*Name) {
304    // Missing ']'
305    return false;
306  }
307
308  std::string SymbolicName(Start, Name - Start);
309
310  for (Index = 0; Index != NumOutputs; ++Index)
311    if (SymbolicName == OutputConstraints[Index].getName())
312      return true;
313
314  return false;
315}
316
317bool TargetInfo::validateInputConstraint(ConstraintInfo *OutputConstraints,
318                                         unsigned NumOutputs,
319                                         ConstraintInfo &Info) const {
320  const char *Name = Info.ConstraintStr.c_str();
321
322  while (*Name) {
323    switch (*Name) {
324    default:
325      // Check if we have a matching constraint
326      if (*Name >= '0' && *Name <= '9') {
327        unsigned i = *Name - '0';
328
329        // Check if matching constraint is out of bounds.
330        if (i >= NumOutputs)
331          return false;
332
333        // The constraint should have the same info as the respective
334        // output constraint.
335        Info.setTiedOperand(i, OutputConstraints[i]);
336      } else if (!validateAsmConstraint(Name, Info)) {
337        // FIXME: This error return is in place temporarily so we can
338        // add more constraints as we hit it.  Eventually, an unknown
339        // constraint should just be treated as 'g'.
340        return false;
341      }
342      break;
343    case '[': {
344      unsigned Index = 0;
345      if (!resolveSymbolicName(Name, OutputConstraints, NumOutputs, Index))
346        return false;
347
348      break;
349    }
350    case '%': // commutative
351      // FIXME: Fail if % is used with the last operand.
352      break;
353    case 'i': // immediate integer.
354    case 'n': // immediate integer with a known value.
355      break;
356    case 'I':  // Various constant constraints with target-specific meanings.
357    case 'J':
358    case 'K':
359    case 'L':
360    case 'M':
361    case 'N':
362    case 'O':
363    case 'P':
364      break;
365    case 'r': // general register.
366      Info.setAllowsRegister();
367      break;
368    case 'm': // memory operand.
369    case 'o': // offsettable memory operand
370    case 'V': // non-offsettable memory operand
371      Info.setAllowsMemory();
372      break;
373    case 'g': // general register, memory operand or immediate integer.
374    case 'X': // any operand.
375      Info.setAllowsRegister();
376      Info.setAllowsMemory();
377      break;
378    }
379
380    Name++;
381  }
382
383  return true;
384}
385