IdentifierTable.cpp revision 239462 
1//===--- IdentifierTable.cpp - Hash table for identifier lookup -----------===//
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 IdentifierInfo, IdentifierVisitor, and
11// IdentifierTable interfaces.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/Basic/IdentifierTable.h"
16#include "clang/Basic/LangOptions.h"
17#include "llvm/ADT/FoldingSet.h"
18#include "llvm/ADT/DenseMap.h"
19#include "llvm/ADT/SmallString.h"
20#include "llvm/ADT/StringSwitch.h"
21#include "llvm/Support/raw_ostream.h"
22#include "llvm/Support/ErrorHandling.h"
23#include <cctype>
24#include <cstdio>
25
26using namespace clang;
27
28//===----------------------------------------------------------------------===//
29// IdentifierInfo Implementation
30//===----------------------------------------------------------------------===//
31
32IdentifierInfo::IdentifierInfo() {
33  TokenID = tok::identifier;
34  ObjCOrBuiltinID = 0;
35  HasMacro = false;
36  IsExtension = false;
37  IsCXX11CompatKeyword = false;
38  IsPoisoned = false;
39  IsCPPOperatorKeyword = false;
40  NeedsHandleIdentifier = false;
41  IsFromAST = false;
42  ChangedAfterLoad = false;
43  RevertedTokenID = false;
44  OutOfDate = false;
45  IsModulesImport = false;
46  FETokenInfo = 0;
47  Entry = 0;
48}
49
50//===----------------------------------------------------------------------===//
51// IdentifierTable Implementation
52//===----------------------------------------------------------------------===//
53
54IdentifierIterator::~IdentifierIterator() { }
55
56IdentifierInfoLookup::~IdentifierInfoLookup() {}
57
58namespace {
59  /// \brief A simple identifier lookup iterator that represents an
60  /// empty sequence of identifiers.
61  class EmptyLookupIterator : public IdentifierIterator
62  {
63  public:
64    virtual StringRef Next() { return StringRef(); }
65  };
66}
67
68IdentifierIterator *IdentifierInfoLookup::getIdentifiers() const {
69  return new EmptyLookupIterator();
70}
71
72ExternalIdentifierLookup::~ExternalIdentifierLookup() {}
73
74IdentifierTable::IdentifierTable(const LangOptions &LangOpts,
75                                 IdentifierInfoLookup* externalLookup)
76  : HashTable(8192), // Start with space for 8K identifiers.
77    ExternalLookup(externalLookup) {
78
79  // Populate the identifier table with info about keywords for the current
80  // language.
81  AddKeywords(LangOpts);
82
83
84  // Add the '_experimental_modules_import' contextual keyword.
85  get("__experimental_modules_import").setModulesImport(true);
86}
87
88//===----------------------------------------------------------------------===//
89// Language Keyword Implementation
90//===----------------------------------------------------------------------===//
91
92// Constants for TokenKinds.def
93namespace {
94  enum {
95    KEYC99 = 0x1,
96    KEYCXX = 0x2,
97    KEYCXX0X = 0x4,
98    KEYGNU = 0x8,
99    KEYMS = 0x10,
100    BOOLSUPPORT = 0x20,
101    KEYALTIVEC = 0x40,
102    KEYNOCXX = 0x80,
103    KEYBORLAND = 0x100,
104    KEYOPENCL = 0x200,
105    KEYC11 = 0x400,
106    KEYARC = 0x800,
107    KEYNOMS = 0x01000,
108    KEYALL = (0xffff & ~KEYNOMS) // Because KEYNOMS is used to exclude.
109  };
110}
111
112/// AddKeyword - This method is used to associate a token ID with specific
113/// identifiers because they are language keywords.  This causes the lexer to
114/// automatically map matching identifiers to specialized token codes.
115///
116/// The C90/C99/CPP/CPP0x flags are set to 3 if the token is a keyword in a
117/// future language standard, set to 2 if the token should be enabled in the
118/// specified language, set to 1 if it is an extension in the specified
119/// language, and set to 0 if disabled in the specified language.
120static void AddKeyword(StringRef Keyword,
121                       tok::TokenKind TokenCode, unsigned Flags,
122                       const LangOptions &LangOpts, IdentifierTable &Table) {
123  unsigned AddResult = 0;
124  if (Flags == KEYALL) AddResult = 2;
125  else if (LangOpts.CPlusPlus && (Flags & KEYCXX)) AddResult = 2;
126  else if (LangOpts.CPlusPlus0x && (Flags & KEYCXX0X)) AddResult = 2;
127  else if (LangOpts.C99 && (Flags & KEYC99)) AddResult = 2;
128  else if (LangOpts.GNUKeywords && (Flags & KEYGNU)) AddResult = 1;
129  else if (LangOpts.MicrosoftExt && (Flags & KEYMS)) AddResult = 1;
130  else if (LangOpts.Borland && (Flags & KEYBORLAND)) AddResult = 1;
131  else if (LangOpts.Bool && (Flags & BOOLSUPPORT)) AddResult = 2;
132  else if (LangOpts.AltiVec && (Flags & KEYALTIVEC)) AddResult = 2;
133  else if (LangOpts.OpenCL && (Flags & KEYOPENCL)) AddResult = 2;
134  else if (!LangOpts.CPlusPlus && (Flags & KEYNOCXX)) AddResult = 2;
135  else if (LangOpts.C11 && (Flags & KEYC11)) AddResult = 2;
136  // We treat bridge casts as objective-C keywords so we can warn on them
137  // in non-arc mode.
138  else if (LangOpts.ObjC2 && (Flags & KEYARC)) AddResult = 2;
139  else if (LangOpts.CPlusPlus && (Flags & KEYCXX0X)) AddResult = 3;
140
141  // Don't add this keyword under MicrosoftMode.
142  if (LangOpts.MicrosoftMode && (Flags & KEYNOMS))
143     return;
144  // Don't add this keyword if disabled in this language.
145  if (AddResult == 0) return;
146
147  IdentifierInfo &Info =
148      Table.get(Keyword, AddResult == 3 ? tok::identifier : TokenCode);
149  Info.setIsExtensionToken(AddResult == 1);
150  Info.setIsCXX11CompatKeyword(AddResult == 3);
151}
152
153/// AddCXXOperatorKeyword - Register a C++ operator keyword alternative
154/// representations.
155static void AddCXXOperatorKeyword(StringRef Keyword,
156                                  tok::TokenKind TokenCode,
157                                  IdentifierTable &Table) {
158  IdentifierInfo &Info = Table.get(Keyword, TokenCode);
159  Info.setIsCPlusPlusOperatorKeyword();
160}
161
162/// AddObjCKeyword - Register an Objective-C \@keyword like "class" "selector"
163/// or "property".
164static void AddObjCKeyword(StringRef Name,
165                           tok::ObjCKeywordKind ObjCID,
166                           IdentifierTable &Table) {
167  Table.get(Name).setObjCKeywordID(ObjCID);
168}
169
170/// AddKeywords - Add all keywords to the symbol table.
171///
172void IdentifierTable::AddKeywords(const LangOptions &LangOpts) {
173  // Add keywords and tokens for the current language.
174#define KEYWORD(NAME, FLAGS) \
175  AddKeyword(StringRef(#NAME), tok::kw_ ## NAME,  \
176             FLAGS, LangOpts, *this);
177#define ALIAS(NAME, TOK, FLAGS) \
178  AddKeyword(StringRef(NAME), tok::kw_ ## TOK,  \
179             FLAGS, LangOpts, *this);
180#define CXX_KEYWORD_OPERATOR(NAME, ALIAS) \
181  if (LangOpts.CXXOperatorNames)          \
182    AddCXXOperatorKeyword(StringRef(#NAME), tok::ALIAS, *this);
183#define OBJC1_AT_KEYWORD(NAME) \
184  if (LangOpts.ObjC1)          \
185    AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
186#define OBJC2_AT_KEYWORD(NAME) \
187  if (LangOpts.ObjC2)          \
188    AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
189#define TESTING_KEYWORD(NAME, FLAGS)
190#include "clang/Basic/TokenKinds.def"
191
192  if (LangOpts.ParseUnknownAnytype)
193    AddKeyword("__unknown_anytype", tok::kw___unknown_anytype, KEYALL,
194               LangOpts, *this);
195}
196
197tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const {
198  // We use a perfect hash function here involving the length of the keyword,
199  // the first and third character.  For preprocessor ID's there are no
200  // collisions (if there were, the switch below would complain about duplicate
201  // case values).  Note that this depends on 'if' being null terminated.
202
203#define HASH(LEN, FIRST, THIRD) \
204  (LEN << 5) + (((FIRST-'a') + (THIRD-'a')) & 31)
205#define CASE(LEN, FIRST, THIRD, NAME) \
206  case HASH(LEN, FIRST, THIRD): \
207    return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME
208
209  unsigned Len = getLength();
210  if (Len < 2) return tok::pp_not_keyword;
211  const char *Name = getNameStart();
212  switch (HASH(Len, Name[0], Name[2])) {
213  default: return tok::pp_not_keyword;
214  CASE( 2, 'i', '\0', if);
215  CASE( 4, 'e', 'i', elif);
216  CASE( 4, 'e', 's', else);
217  CASE( 4, 'l', 'n', line);
218  CASE( 4, 's', 'c', sccs);
219  CASE( 5, 'e', 'd', endif);
220  CASE( 5, 'e', 'r', error);
221  CASE( 5, 'i', 'e', ident);
222  CASE( 5, 'i', 'd', ifdef);
223  CASE( 5, 'u', 'd', undef);
224
225  CASE( 6, 'a', 's', assert);
226  CASE( 6, 'd', 'f', define);
227  CASE( 6, 'i', 'n', ifndef);
228  CASE( 6, 'i', 'p', import);
229  CASE( 6, 'p', 'a', pragma);
230
231  CASE( 7, 'd', 'f', defined);
232  CASE( 7, 'i', 'c', include);
233  CASE( 7, 'w', 'r', warning);
234
235  CASE( 8, 'u', 'a', unassert);
236  CASE(12, 'i', 'c', include_next);
237
238  CASE(14, '_', 'p', __public_macro);
239
240  CASE(15, '_', 'p', __private_macro);
241
242  CASE(16, '_', 'i', __include_macros);
243#undef CASE
244#undef HASH
245  }
246}
247
248//===----------------------------------------------------------------------===//
249// Stats Implementation
250//===----------------------------------------------------------------------===//
251
252/// PrintStats - Print statistics about how well the identifier table is doing
253/// at hashing identifiers.
254void IdentifierTable::PrintStats() const {
255  unsigned NumBuckets = HashTable.getNumBuckets();
256  unsigned NumIdentifiers = HashTable.getNumItems();
257  unsigned NumEmptyBuckets = NumBuckets-NumIdentifiers;
258  unsigned AverageIdentifierSize = 0;
259  unsigned MaxIdentifierLength = 0;
260
261  // TODO: Figure out maximum times an identifier had to probe for -stats.
262  for (llvm::StringMap<IdentifierInfo*, llvm::BumpPtrAllocator>::const_iterator
263       I = HashTable.begin(), E = HashTable.end(); I != E; ++I) {
264    unsigned IdLen = I->getKeyLength();
265    AverageIdentifierSize += IdLen;
266    if (MaxIdentifierLength < IdLen)
267      MaxIdentifierLength = IdLen;
268  }
269
270  fprintf(stderr, "\n*** Identifier Table Stats:\n");
271  fprintf(stderr, "# Identifiers:   %d\n", NumIdentifiers);
272  fprintf(stderr, "# Empty Buckets: %d\n", NumEmptyBuckets);
273  fprintf(stderr, "Hash density (#identifiers per bucket): %f\n",
274          NumIdentifiers/(double)NumBuckets);
275  fprintf(stderr, "Ave identifier length: %f\n",
276          (AverageIdentifierSize/(double)NumIdentifiers));
277  fprintf(stderr, "Max identifier length: %d\n", MaxIdentifierLength);
278
279  // Compute statistics about the memory allocated for identifiers.
280  HashTable.getAllocator().PrintStats();
281}
282
283//===----------------------------------------------------------------------===//
284// SelectorTable Implementation
285//===----------------------------------------------------------------------===//
286
287unsigned llvm::DenseMapInfo<clang::Selector>::getHashValue(clang::Selector S) {
288  return DenseMapInfo<void*>::getHashValue(S.getAsOpaquePtr());
289}
290
291namespace clang {
292/// MultiKeywordSelector - One of these variable length records is kept for each
293/// selector containing more than one keyword. We use a folding set
294/// to unique aggregate names (keyword selectors in ObjC parlance). Access to
295/// this class is provided strictly through Selector.
296class MultiKeywordSelector
297  : public DeclarationNameExtra, public llvm::FoldingSetNode {
298  MultiKeywordSelector(unsigned nKeys) {
299    ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
300  }
301public:
302  // Constructor for keyword selectors.
303  MultiKeywordSelector(unsigned nKeys, IdentifierInfo **IIV) {
304    assert((nKeys > 1) && "not a multi-keyword selector");
305    ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
306
307    // Fill in the trailing keyword array.
308    IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this+1);
309    for (unsigned i = 0; i != nKeys; ++i)
310      KeyInfo[i] = IIV[i];
311  }
312
313  // getName - Derive the full selector name and return it.
314  std::string getName() const;
315
316  unsigned getNumArgs() const { return ExtraKindOrNumArgs - NUM_EXTRA_KINDS; }
317
318  typedef IdentifierInfo *const *keyword_iterator;
319  keyword_iterator keyword_begin() const {
320    return reinterpret_cast<keyword_iterator>(this+1);
321  }
322  keyword_iterator keyword_end() const {
323    return keyword_begin()+getNumArgs();
324  }
325  IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const {
326    assert(i < getNumArgs() && "getIdentifierInfoForSlot(): illegal index");
327    return keyword_begin()[i];
328  }
329  static void Profile(llvm::FoldingSetNodeID &ID,
330                      keyword_iterator ArgTys, unsigned NumArgs) {
331    ID.AddInteger(NumArgs);
332    for (unsigned i = 0; i != NumArgs; ++i)
333      ID.AddPointer(ArgTys[i]);
334  }
335  void Profile(llvm::FoldingSetNodeID &ID) {
336    Profile(ID, keyword_begin(), getNumArgs());
337  }
338};
339} // end namespace clang.
340
341unsigned Selector::getNumArgs() const {
342  unsigned IIF = getIdentifierInfoFlag();
343  if (IIF <= ZeroArg)
344    return 0;
345  if (IIF == OneArg)
346    return 1;
347  // We point to a MultiKeywordSelector.
348  MultiKeywordSelector *SI = getMultiKeywordSelector();
349  return SI->getNumArgs();
350}
351
352IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
353  if (getIdentifierInfoFlag() < MultiArg) {
354    assert(argIndex == 0 && "illegal keyword index");
355    return getAsIdentifierInfo();
356  }
357  // We point to a MultiKeywordSelector.
358  MultiKeywordSelector *SI = getMultiKeywordSelector();
359  return SI->getIdentifierInfoForSlot(argIndex);
360}
361
362StringRef Selector::getNameForSlot(unsigned int argIndex) const {
363  IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
364  return II? II->getName() : StringRef();
365}
366
367std::string MultiKeywordSelector::getName() const {
368  SmallString<256> Str;
369  llvm::raw_svector_ostream OS(Str);
370  for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
371    if (*I)
372      OS << (*I)->getName();
373    OS << ':';
374  }
375
376  return OS.str();
377}
378
379std::string Selector::getAsString() const {
380  if (InfoPtr == 0)
381    return "<null selector>";
382
383  if (getIdentifierInfoFlag() < MultiArg) {
384    IdentifierInfo *II = getAsIdentifierInfo();
385
386    // If the number of arguments is 0 then II is guaranteed to not be null.
387    if (getNumArgs() == 0)
388      return II->getName();
389
390    if (!II)
391      return ":";
392
393    return II->getName().str() + ":";
394  }
395
396  // We have a multiple keyword selector.
397  return getMultiKeywordSelector()->getName();
398}
399
400/// Interpreting the given string using the normal CamelCase
401/// conventions, determine whether the given string starts with the
402/// given "word", which is assumed to end in a lowercase letter.
403static bool startsWithWord(StringRef name, StringRef word) {
404  if (name.size() < word.size()) return false;
405  return ((name.size() == word.size() ||
406           !islower(name[word.size()]))
407          && name.startswith(word));
408}
409
410ObjCMethodFamily Selector::getMethodFamilyImpl(Selector sel) {
411  IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
412  if (!first) return OMF_None;
413
414  StringRef name = first->getName();
415  if (sel.isUnarySelector()) {
416    if (name == "autorelease") return OMF_autorelease;
417    if (name == "dealloc") return OMF_dealloc;
418    if (name == "finalize") return OMF_finalize;
419    if (name == "release") return OMF_release;
420    if (name == "retain") return OMF_retain;
421    if (name == "retainCount") return OMF_retainCount;
422    if (name == "self") return OMF_self;
423  }
424
425  if (name == "performSelector") return OMF_performSelector;
426
427  // The other method families may begin with a prefix of underscores.
428  while (!name.empty() && name.front() == '_')
429    name = name.substr(1);
430
431  if (name.empty()) return OMF_None;
432  switch (name.front()) {
433  case 'a':
434    if (startsWithWord(name, "alloc")) return OMF_alloc;
435    break;
436  case 'c':
437    if (startsWithWord(name, "copy")) return OMF_copy;
438    break;
439  case 'i':
440    if (startsWithWord(name, "init")) return OMF_init;
441    break;
442  case 'm':
443    if (startsWithWord(name, "mutableCopy")) return OMF_mutableCopy;
444    break;
445  case 'n':
446    if (startsWithWord(name, "new")) return OMF_new;
447    break;
448  default:
449    break;
450  }
451
452  return OMF_None;
453}
454
455namespace {
456  struct SelectorTableImpl {
457    llvm::FoldingSet<MultiKeywordSelector> Table;
458    llvm::BumpPtrAllocator Allocator;
459  };
460} // end anonymous namespace.
461
462static SelectorTableImpl &getSelectorTableImpl(void *P) {
463  return *static_cast<SelectorTableImpl*>(P);
464}
465
466/*static*/ Selector
467SelectorTable::constructSetterName(IdentifierTable &Idents,
468                                   SelectorTable &SelTable,
469                                   const IdentifierInfo *Name) {
470  SmallString<100> SelectorName;
471  SelectorName = "set";
472  SelectorName += Name->getName();
473  SelectorName[3] = toupper(SelectorName[3]);
474  IdentifierInfo *SetterName = &Idents.get(SelectorName);
475  return SelTable.getUnarySelector(SetterName);
476}
477
478size_t SelectorTable::getTotalMemory() const {
479  SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
480  return SelTabImpl.Allocator.getTotalMemory();
481}
482
483Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) {
484  if (nKeys < 2)
485    return Selector(IIV[0], nKeys);
486
487  SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
488
489  // Unique selector, to guarantee there is one per name.
490  llvm::FoldingSetNodeID ID;
491  MultiKeywordSelector::Profile(ID, IIV, nKeys);
492
493  void *InsertPos = 0;
494  if (MultiKeywordSelector *SI =
495        SelTabImpl.Table.FindNodeOrInsertPos(ID, InsertPos))
496    return Selector(SI);
497
498  // MultiKeywordSelector objects are not allocated with new because they have a
499  // variable size array (for parameter types) at the end of them.
500  unsigned Size = sizeof(MultiKeywordSelector) + nKeys*sizeof(IdentifierInfo *);
501  MultiKeywordSelector *SI =
502    (MultiKeywordSelector*)SelTabImpl.Allocator.Allocate(Size,
503                                         llvm::alignOf<MultiKeywordSelector>());
504  new (SI) MultiKeywordSelector(nKeys, IIV);
505  SelTabImpl.Table.InsertNode(SI, InsertPos);
506  return Selector(SI);
507}
508
509SelectorTable::SelectorTable() {
510  Impl = new SelectorTableImpl();
511}
512
513SelectorTable::~SelectorTable() {
514  delete &getSelectorTableImpl(Impl);
515}
516
517const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) {
518  switch (Operator) {
519  case OO_None:
520  case NUM_OVERLOADED_OPERATORS:
521    return 0;
522
523#define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
524  case OO_##Name: return Spelling;
525#include "clang/Basic/OperatorKinds.def"
526  }
527
528  llvm_unreachable("Invalid OverloadedOperatorKind!");
529}
530