TargetInfo.cpp revision 207619 
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}
56
57// Out of line virtual dtor for TargetInfo.
58TargetInfo::~TargetInfo() {}
59
60/// getTypeName - Return the user string for the specified integer type enum.
61/// For example, SignedShort -> "short".
62const char *TargetInfo::getTypeName(IntType T) {
63  switch (T) {
64  default: assert(0 && "not an integer!");
65  case SignedShort:      return "short";
66  case UnsignedShort:    return "unsigned short";
67  case SignedInt:        return "int";
68  case UnsignedInt:      return "unsigned int";
69  case SignedLong:       return "long int";
70  case UnsignedLong:     return "long unsigned int";
71  case SignedLongLong:   return "long long int";
72  case UnsignedLongLong: return "long long unsigned int";
73  }
74}
75
76/// getTypeConstantSuffix - Return the constant suffix for the specified
77/// integer type enum. For example, SignedLong -> "L".
78const char *TargetInfo::getTypeConstantSuffix(IntType T) {
79  switch (T) {
80  default: assert(0 && "not an integer!");
81  case SignedShort:
82  case SignedInt:        return "";
83  case SignedLong:       return "L";
84  case SignedLongLong:   return "LL";
85  case UnsignedShort:
86  case UnsignedInt:      return "U";
87  case UnsignedLong:     return "UL";
88  case UnsignedLongLong: return "ULL";
89  }
90}
91
92/// getTypeWidth - Return the width (in bits) of the specified integer type
93/// enum. For example, SignedInt -> getIntWidth().
94unsigned TargetInfo::getTypeWidth(IntType T) const {
95  switch (T) {
96  default: assert(0 && "not an integer!");
97  case SignedShort:
98  case UnsignedShort:    return getShortWidth();
99  case SignedInt:
100  case UnsignedInt:      return getIntWidth();
101  case SignedLong:
102  case UnsignedLong:     return getLongWidth();
103  case SignedLongLong:
104  case UnsignedLongLong: return getLongLongWidth();
105  };
106}
107
108/// getTypeAlign - Return the alignment (in bits) of the specified integer type
109/// enum. For example, SignedInt -> getIntAlign().
110unsigned TargetInfo::getTypeAlign(IntType T) const {
111  switch (T) {
112  default: assert(0 && "not an integer!");
113  case SignedShort:
114  case UnsignedShort:    return getShortAlign();
115  case SignedInt:
116  case UnsignedInt:      return getIntAlign();
117  case SignedLong:
118  case UnsignedLong:     return getLongAlign();
119  case SignedLongLong:
120  case UnsignedLongLong: return getLongLongAlign();
121  };
122}
123
124/// isTypeSigned - Return whether an integer types is signed. Returns true if
125/// the type is signed; false otherwise.
126bool TargetInfo::isTypeSigned(IntType T) const {
127  switch (T) {
128  default: assert(0 && "not an integer!");
129  case SignedShort:
130  case SignedInt:
131  case SignedLong:
132  case SignedLongLong:
133    return true;
134  case UnsignedShort:
135  case UnsignedInt:
136  case UnsignedLong:
137  case UnsignedLongLong:
138    return false;
139  };
140}
141
142/// setForcedLangOptions - Set forced language options.
143/// Apply changes to the target information with respect to certain
144/// language options which change the target configuration.
145void TargetInfo::setForcedLangOptions(LangOptions &Opts) {
146  if (Opts.NoBitFieldTypeAlign)
147    UseBitFieldTypeAlignment = false;
148  if (Opts.ShortWChar)
149    WCharType = UnsignedShort;
150}
151
152//===----------------------------------------------------------------------===//
153
154
155static llvm::StringRef removeGCCRegisterPrefix(llvm::StringRef Name) {
156  if (Name[0] == '%' || Name[0] == '#')
157    Name = Name.substr(1);
158
159  return Name;
160}
161
162/// isValidGCCRegisterName - Returns whether the passed in string
163/// is a valid register name according to GCC. This is used by Sema for
164/// inline asm statements.
165bool TargetInfo::isValidGCCRegisterName(llvm::StringRef Name) const {
166  if (Name.empty())
167    return false;
168
169  const char * const *Names;
170  unsigned NumNames;
171
172  // Get rid of any register prefix.
173  Name = removeGCCRegisterPrefix(Name);
174
175  if (Name == "memory" || Name == "cc")
176    return true;
177
178  getGCCRegNames(Names, NumNames);
179
180  // If we have a number it maps to an entry in the register name array.
181  if (isdigit(Name[0])) {
182    int n;
183    if (!Name.getAsInteger(0, n))
184      return n >= 0 && (unsigned)n < NumNames;
185  }
186
187  // Check register names.
188  for (unsigned i = 0; i < NumNames; i++) {
189    if (Name == Names[i])
190      return true;
191  }
192
193  // Now check aliases.
194  const GCCRegAlias *Aliases;
195  unsigned NumAliases;
196
197  getGCCRegAliases(Aliases, NumAliases);
198  for (unsigned i = 0; i < NumAliases; i++) {
199    for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
200      if (!Aliases[i].Aliases[j])
201        break;
202      if (Aliases[i].Aliases[j] == Name)
203        return true;
204    }
205  }
206
207  return false;
208}
209
210llvm::StringRef
211TargetInfo::getNormalizedGCCRegisterName(llvm::StringRef Name) const {
212  assert(isValidGCCRegisterName(Name) && "Invalid register passed in");
213
214  // Get rid of any register prefix.
215  Name = removeGCCRegisterPrefix(Name);
216
217  const char * const *Names;
218  unsigned NumNames;
219
220  getGCCRegNames(Names, NumNames);
221
222  // First, check if we have a number.
223  if (isdigit(Name[0])) {
224    int n;
225    if (!Name.getAsInteger(0, n)) {
226      assert(n >= 0 && (unsigned)n < NumNames &&
227             "Out of bounds register number!");
228      return Names[n];
229    }
230  }
231
232  // Now check aliases.
233  const GCCRegAlias *Aliases;
234  unsigned NumAliases;
235
236  getGCCRegAliases(Aliases, NumAliases);
237  for (unsigned i = 0; i < NumAliases; i++) {
238    for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
239      if (!Aliases[i].Aliases[j])
240        break;
241      if (Aliases[i].Aliases[j] == Name)
242        return Aliases[i].Register;
243    }
244  }
245
246  return Name;
247}
248
249bool TargetInfo::validateOutputConstraint(ConstraintInfo &Info) const {
250  const char *Name = Info.getConstraintStr().c_str();
251  // An output constraint must start with '=' or '+'
252  if (*Name != '=' && *Name != '+')
253    return false;
254
255  if (*Name == '+')
256    Info.setIsReadWrite();
257
258  Name++;
259  while (*Name) {
260    switch (*Name) {
261    default:
262      if (!validateAsmConstraint(Name, Info)) {
263        // FIXME: We temporarily return false
264        // so we can add more constraints as we hit it.
265        // Eventually, an unknown constraint should just be treated as 'g'.
266        return false;
267      }
268    case '&': // early clobber.
269      break;
270    case '%': // commutative.
271      // FIXME: Check that there is a another register after this one.
272      break;
273    case 'r': // general register.
274      Info.setAllowsRegister();
275      break;
276    case 'm': // memory operand.
277      Info.setAllowsMemory();
278      break;
279    case 'g': // general register, memory operand or immediate integer.
280    case 'X': // any operand.
281      Info.setAllowsRegister();
282      Info.setAllowsMemory();
283      break;
284    }
285
286    Name++;
287  }
288
289  return true;
290}
291
292bool TargetInfo::resolveSymbolicName(const char *&Name,
293                                     ConstraintInfo *OutputConstraints,
294                                     unsigned NumOutputs,
295                                     unsigned &Index) const {
296  assert(*Name == '[' && "Symbolic name did not start with '['");
297  Name++;
298  const char *Start = Name;
299  while (*Name && *Name != ']')
300    Name++;
301
302  if (!*Name) {
303    // Missing ']'
304    return false;
305  }
306
307  std::string SymbolicName(Start, Name - Start);
308
309  for (Index = 0; Index != NumOutputs; ++Index)
310    if (SymbolicName == OutputConstraints[Index].getName())
311      return true;
312
313  return false;
314}
315
316bool TargetInfo::validateInputConstraint(ConstraintInfo *OutputConstraints,
317                                         unsigned NumOutputs,
318                                         ConstraintInfo &Info) const {
319  const char *Name = Info.ConstraintStr.c_str();
320
321  while (*Name) {
322    switch (*Name) {
323    default:
324      // Check if we have a matching constraint
325      if (*Name >= '0' && *Name <= '9') {
326        unsigned i = *Name - '0';
327
328        // Check if matching constraint is out of bounds.
329        if (i >= NumOutputs)
330          return false;
331
332        // The constraint should have the same info as the respective
333        // output constraint.
334        Info.setTiedOperand(i, OutputConstraints[i]);
335      } else if (!validateAsmConstraint(Name, Info)) {
336        // FIXME: This error return is in place temporarily so we can
337        // add more constraints as we hit it.  Eventually, an unknown
338        // constraint should just be treated as 'g'.
339        return false;
340      }
341      break;
342    case '[': {
343      unsigned Index = 0;
344      if (!resolveSymbolicName(Name, OutputConstraints, NumOutputs, Index))
345        return false;
346
347      break;
348    }
349    case '%': // commutative
350      // FIXME: Fail if % is used with the last operand.
351      break;
352    case 'i': // immediate integer.
353    case 'n': // immediate integer with a known value.
354      break;
355    case 'I':  // Various constant constraints with target-specific meanings.
356    case 'J':
357    case 'K':
358    case 'L':
359    case 'M':
360    case 'N':
361    case 'O':
362    case 'P':
363      break;
364    case 'r': // general register.
365      Info.setAllowsRegister();
366      break;
367    case 'm': // memory operand.
368    case 'o': // offsettable memory operand
369    case 'V': // non-offsettable memory operand
370      Info.setAllowsMemory();
371      break;
372    case 'g': // general register, memory operand or immediate integer.
373    case 'X': // any operand.
374      Info.setAllowsRegister();
375      Info.setAllowsMemory();
376      break;
377    }
378
379    Name++;
380  }
381
382  return true;
383}
384