TargetInfo.cpp revision 68086b9ad26c471322449ea1c030c2ac8397fd07 
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  LargeArrayMinWidth = 0;
38  LargeArrayAlign = 0;
39  SizeType = UnsignedLong;
40  PtrDiffType = SignedLong;
41  IntMaxType = SignedLongLong;
42  UIntMaxType = UnsignedLongLong;
43  IntPtrType = SignedLong;
44  WCharType = SignedInt;
45  WIntType = SignedInt;
46  Char16Type = UnsignedShort;
47  Char32Type = UnsignedInt;
48  Int64Type = SignedLongLong;
49  SigAtomicType = SignedInt;
50  UseBitFieldTypeAlignment = true;
51  FloatFormat = &llvm::APFloat::IEEEsingle;
52  DoubleFormat = &llvm::APFloat::IEEEdouble;
53  LongDoubleFormat = &llvm::APFloat::IEEEdouble;
54  DescriptionString = "E-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-"
55                      "i64:64:64-f32:32:32-f64:64:64-n32";
56  UserLabelPrefix = "_";
57  HasAlignMac68kSupport = false;
58
59  // Default to no types using fpret.
60  RealTypeUsesObjCFPRet = 0;
61
62  // Default to using the Itanium ABI.
63  CXXABI = CXXABI_Itanium;
64}
65
66// Out of line virtual dtor for TargetInfo.
67TargetInfo::~TargetInfo() {}
68
69/// getTypeName - Return the user string for the specified integer type enum.
70/// For example, SignedShort -> "short".
71const char *TargetInfo::getTypeName(IntType T) {
72  switch (T) {
73  default: assert(0 && "not an integer!");
74  case SignedShort:      return "short";
75  case UnsignedShort:    return "unsigned short";
76  case SignedInt:        return "int";
77  case UnsignedInt:      return "unsigned int";
78  case SignedLong:       return "long int";
79  case UnsignedLong:     return "long unsigned int";
80  case SignedLongLong:   return "long long int";
81  case UnsignedLongLong: return "long long unsigned int";
82  }
83}
84
85/// getTypeConstantSuffix - Return the constant suffix for the specified
86/// integer type enum. For example, SignedLong -> "L".
87const char *TargetInfo::getTypeConstantSuffix(IntType T) {
88  switch (T) {
89  default: assert(0 && "not an integer!");
90  case SignedShort:
91  case SignedInt:        return "";
92  case SignedLong:       return "L";
93  case SignedLongLong:   return "LL";
94  case UnsignedShort:
95  case UnsignedInt:      return "U";
96  case UnsignedLong:     return "UL";
97  case UnsignedLongLong: return "ULL";
98  }
99}
100
101/// getTypeWidth - Return the width (in bits) of the specified integer type
102/// enum. For example, SignedInt -> getIntWidth().
103unsigned TargetInfo::getTypeWidth(IntType T) const {
104  switch (T) {
105  default: assert(0 && "not an integer!");
106  case SignedShort:
107  case UnsignedShort:    return getShortWidth();
108  case SignedInt:
109  case UnsignedInt:      return getIntWidth();
110  case SignedLong:
111  case UnsignedLong:     return getLongWidth();
112  case SignedLongLong:
113  case UnsignedLongLong: return getLongLongWidth();
114  };
115}
116
117/// getTypeAlign - Return the alignment (in bits) of the specified integer type
118/// enum. For example, SignedInt -> getIntAlign().
119unsigned TargetInfo::getTypeAlign(IntType T) const {
120  switch (T) {
121  default: assert(0 && "not an integer!");
122  case SignedShort:
123  case UnsignedShort:    return getShortAlign();
124  case SignedInt:
125  case UnsignedInt:      return getIntAlign();
126  case SignedLong:
127  case UnsignedLong:     return getLongAlign();
128  case SignedLongLong:
129  case UnsignedLongLong: return getLongLongAlign();
130  };
131}
132
133/// isTypeSigned - Return whether an integer types is signed. Returns true if
134/// the type is signed; false otherwise.
135bool TargetInfo::isTypeSigned(IntType T) const {
136  switch (T) {
137  default: assert(0 && "not an integer!");
138  case SignedShort:
139  case SignedInt:
140  case SignedLong:
141  case SignedLongLong:
142    return true;
143  case UnsignedShort:
144  case UnsignedInt:
145  case UnsignedLong:
146  case UnsignedLongLong:
147    return false;
148  };
149}
150
151/// setForcedLangOptions - Set forced language options.
152/// Apply changes to the target information with respect to certain
153/// language options which change the target configuration.
154void TargetInfo::setForcedLangOptions(LangOptions &Opts) {
155  if (Opts.NoBitFieldTypeAlign)
156    UseBitFieldTypeAlignment = false;
157  if (Opts.ShortWChar)
158    WCharType = UnsignedShort;
159}
160
161//===----------------------------------------------------------------------===//
162
163
164static llvm::StringRef removeGCCRegisterPrefix(llvm::StringRef Name) {
165  if (Name[0] == '%' || Name[0] == '#')
166    Name = Name.substr(1);
167
168  return Name;
169}
170
171/// isValidGCCRegisterName - Returns whether the passed in string
172/// is a valid register name according to GCC. This is used by Sema for
173/// inline asm statements.
174bool TargetInfo::isValidGCCRegisterName(llvm::StringRef Name) const {
175  if (Name.empty())
176    return false;
177
178  const char * const *Names;
179  unsigned NumNames;
180
181  // Get rid of any register prefix.
182  Name = removeGCCRegisterPrefix(Name);
183
184  if (Name == "memory" || Name == "cc")
185    return true;
186
187  getGCCRegNames(Names, NumNames);
188
189  // If we have a number it maps to an entry in the register name array.
190  if (isdigit(Name[0])) {
191    int n;
192    if (!Name.getAsInteger(0, n))
193      return n >= 0 && (unsigned)n < NumNames;
194  }
195
196  // Check register names.
197  for (unsigned i = 0; i < NumNames; i++) {
198    if (Name == Names[i])
199      return true;
200  }
201
202  // Now check aliases.
203  const GCCRegAlias *Aliases;
204  unsigned NumAliases;
205
206  getGCCRegAliases(Aliases, NumAliases);
207  for (unsigned i = 0; i < NumAliases; i++) {
208    for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
209      if (!Aliases[i].Aliases[j])
210        break;
211      if (Aliases[i].Aliases[j] == Name)
212        return true;
213    }
214  }
215
216  return false;
217}
218
219llvm::StringRef
220TargetInfo::getNormalizedGCCRegisterName(llvm::StringRef Name) const {
221  assert(isValidGCCRegisterName(Name) && "Invalid register passed in");
222
223  // Get rid of any register prefix.
224  Name = removeGCCRegisterPrefix(Name);
225
226  const char * const *Names;
227  unsigned NumNames;
228
229  getGCCRegNames(Names, NumNames);
230
231  // First, check if we have a number.
232  if (isdigit(Name[0])) {
233    int n;
234    if (!Name.getAsInteger(0, n)) {
235      assert(n >= 0 && (unsigned)n < NumNames &&
236             "Out of bounds register number!");
237      return Names[n];
238    }
239  }
240
241  // Now check aliases.
242  const GCCRegAlias *Aliases;
243  unsigned NumAliases;
244
245  getGCCRegAliases(Aliases, NumAliases);
246  for (unsigned i = 0; i < NumAliases; i++) {
247    for (unsigned j = 0 ; j < llvm::array_lengthof(Aliases[i].Aliases); j++) {
248      if (!Aliases[i].Aliases[j])
249        break;
250      if (Aliases[i].Aliases[j] == Name)
251        return Aliases[i].Register;
252    }
253  }
254
255  return Name;
256}
257
258bool TargetInfo::validateOutputConstraint(ConstraintInfo &Info) const {
259  const char *Name = Info.getConstraintStr().c_str();
260  // An output constraint must start with '=' or '+'
261  if (*Name != '=' && *Name != '+')
262    return false;
263
264  if (*Name == '+')
265    Info.setIsReadWrite();
266
267  Name++;
268  while (*Name) {
269    switch (*Name) {
270    default:
271      if (!validateAsmConstraint(Name, Info)) {
272        // FIXME: We temporarily return false
273        // so we can add more constraints as we hit it.
274        // Eventually, an unknown constraint should just be treated as 'g'.
275        return false;
276      }
277    case '&': // early clobber.
278      break;
279    case '%': // commutative.
280      // FIXME: Check that there is a another register after this one.
281      break;
282    case 'r': // general register.
283      Info.setAllowsRegister();
284      break;
285    case 'm': // memory operand.
286      Info.setAllowsMemory();
287      break;
288    case 'g': // general register, memory operand or immediate integer.
289    case 'X': // any operand.
290      Info.setAllowsRegister();
291      Info.setAllowsMemory();
292      break;
293    case ',': // multiple alternative constraint.  Pass it.
294      Name++;
295      // Handle additional optional '=' or '+' modifiers.
296      if (*Name == '=' || *Name == '+')
297        Name++;
298      break;
299    case '?': // Disparage slightly code.
300    case '!': // Disparage severly.
301      break;  // Pass them.
302    }
303
304    Name++;
305  }
306
307  return true;
308}
309
310bool TargetInfo::resolveSymbolicName(const char *&Name,
311                                     ConstraintInfo *OutputConstraints,
312                                     unsigned NumOutputs,
313                                     unsigned &Index) const {
314  assert(*Name == '[' && "Symbolic name did not start with '['");
315  Name++;
316  const char *Start = Name;
317  while (*Name && *Name != ']')
318    Name++;
319
320  if (!*Name) {
321    // Missing ']'
322    return false;
323  }
324
325  std::string SymbolicName(Start, Name - Start);
326
327  for (Index = 0; Index != NumOutputs; ++Index)
328    if (SymbolicName == OutputConstraints[Index].getName())
329      return true;
330
331  return false;
332}
333
334bool TargetInfo::validateInputConstraint(ConstraintInfo *OutputConstraints,
335                                         unsigned NumOutputs,
336                                         ConstraintInfo &Info) const {
337  const char *Name = Info.ConstraintStr.c_str();
338
339  while (*Name) {
340    switch (*Name) {
341    default:
342      // Check if we have a matching constraint
343      if (*Name >= '0' && *Name <= '9') {
344        unsigned i = *Name - '0';
345
346        // Check if matching constraint is out of bounds.
347        if (i >= NumOutputs)
348          return false;
349
350        // The constraint should have the same info as the respective
351        // output constraint.
352        Info.setTiedOperand(i, OutputConstraints[i]);
353      } else if (!validateAsmConstraint(Name, Info)) {
354        // FIXME: This error return is in place temporarily so we can
355        // add more constraints as we hit it.  Eventually, an unknown
356        // constraint should just be treated as 'g'.
357        return false;
358      }
359      break;
360    case '[': {
361      unsigned Index = 0;
362      if (!resolveSymbolicName(Name, OutputConstraints, NumOutputs, Index))
363        return false;
364
365      Info.setTiedOperand(Index, OutputConstraints[Index]);
366      break;
367    }
368    case '%': // commutative
369      // FIXME: Fail if % is used with the last operand.
370      break;
371    case 'i': // immediate integer.
372    case 'n': // immediate integer with a known value.
373      break;
374    case 'I':  // Various constant constraints with target-specific meanings.
375    case 'J':
376    case 'K':
377    case 'L':
378    case 'M':
379    case 'N':
380    case 'O':
381    case 'P':
382      break;
383    case 'r': // general register.
384      Info.setAllowsRegister();
385      break;
386    case 'm': // memory operand.
387    case 'o': // offsettable memory operand
388    case 'V': // non-offsettable memory operand
389      Info.setAllowsMemory();
390      break;
391    case 'g': // general register, memory operand or immediate integer.
392    case 'X': // any operand.
393      Info.setAllowsRegister();
394      Info.setAllowsMemory();
395      break;
396    case ',': // multiple alternative constraint.  Ignore comma.
397      break;
398    case '?': // Disparage slightly code.
399    case '!': // Disparage severly.
400      break;  // Pass them.
401    }
402
403    Name++;
404  }
405
406  return true;
407}
408