clang  3.9.0
IdentifierResolver.cpp
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1 //===- IdentifierResolver.cpp - Lexical Scope Name lookup -------*- C++ -*-===//
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 IdentifierResolver class, which is used for lexical
11 // scoped lookup, based on declaration names.
12 //
13 //===----------------------------------------------------------------------===//
14 
16 #include "clang/AST/Decl.h"
19 #include "clang/Lex/Preprocessor.h"
20 #include "clang/Sema/Scope.h"
21 
22 using namespace clang;
23 
24 //===----------------------------------------------------------------------===//
25 // IdDeclInfoMap class
26 //===----------------------------------------------------------------------===//
27 
28 /// IdDeclInfoMap - Associates IdDeclInfos with declaration names.
29 /// Allocates 'pools' (vectors of IdDeclInfos) to avoid allocating each
30 /// individual IdDeclInfo to heap.
32  static const unsigned int POOL_SIZE = 512;
33 
34  /// We use our own linked-list implementation because it is sadly
35  /// impossible to add something to a pre-C++0x STL container without
36  /// a completely unnecessary copy.
37  struct IdDeclInfoPool {
38  IdDeclInfoPool(IdDeclInfoPool *Next) : Next(Next) {}
39 
40  IdDeclInfoPool *Next;
41  IdDeclInfo Pool[POOL_SIZE];
42  };
43 
44  IdDeclInfoPool *CurPool;
45  unsigned int CurIndex;
46 
47 public:
48  IdDeclInfoMap() : CurPool(nullptr), CurIndex(POOL_SIZE) {}
49 
51  IdDeclInfoPool *Cur = CurPool;
52  while (IdDeclInfoPool *P = Cur) {
53  Cur = Cur->Next;
54  delete P;
55  }
56  }
57 
58  /// Returns the IdDeclInfo associated to the DeclarationName.
59  /// It creates a new IdDeclInfo if one was not created before for this id.
60  IdDeclInfo &operator[](DeclarationName Name);
61 };
62 
63 
64 //===----------------------------------------------------------------------===//
65 // IdDeclInfo Implementation
66 //===----------------------------------------------------------------------===//
67 
68 /// RemoveDecl - Remove the decl from the scope chain.
69 /// The decl must already be part of the decl chain.
70 void IdentifierResolver::IdDeclInfo::RemoveDecl(NamedDecl *D) {
71  for (DeclsTy::iterator I = Decls.end(); I != Decls.begin(); --I) {
72  if (D == *(I-1)) {
73  Decls.erase(I-1);
74  return;
75  }
76  }
77 
78  llvm_unreachable("Didn't find this decl on its identifier's chain!");
79 }
80 
81 //===----------------------------------------------------------------------===//
82 // IdentifierResolver Implementation
83 //===----------------------------------------------------------------------===//
84 
86  : LangOpt(PP.getLangOpts()), PP(PP),
87  IdDeclInfos(new IdDeclInfoMap) {
88 }
89 
91  delete IdDeclInfos;
92 }
93 
94 /// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
95 /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
96 /// true if 'D' belongs to the given declaration context.
98  bool AllowInlineNamespace) const {
99  Ctx = Ctx->getRedeclContext();
100 
101  if (Ctx->isFunctionOrMethod() || (S && S->isFunctionPrototypeScope())) {
102  // Ignore the scopes associated within transparent declaration contexts.
103  while (S->getEntity() && S->getEntity()->isTransparentContext())
104  S = S->getParent();
105 
106  if (S->isDeclScope(D))
107  return true;
108  if (LangOpt.CPlusPlus) {
109  // C++ 3.3.2p3:
110  // The name declared in a catch exception-declaration is local to the
111  // handler and shall not be redeclared in the outermost block of the
112  // handler.
113  // C++ 3.3.2p4:
114  // Names declared in the for-init-statement, and in the condition of if,
115  // while, for, and switch statements are local to the if, while, for, or
116  // switch statement (including the controlled statement), and shall not be
117  // redeclared in a subsequent condition of that statement nor in the
118  // outermost block (or, for the if statement, any of the outermost blocks)
119  // of the controlled statement.
120  //
121  assert(S->getParent() && "No TUScope?");
122  if (S->getParent()->getFlags() & Scope::ControlScope) {
123  S = S->getParent();
124  if (S->isDeclScope(D))
125  return true;
126  }
127  if (S->getFlags() & Scope::FnTryCatchScope)
128  return S->getParent()->isDeclScope(D);
129  }
130  return false;
131  }
132 
133  // FIXME: If D is a local extern declaration, this check doesn't make sense;
134  // we should be checking its lexical context instead in that case, because
135  // that is its scope.
136  DeclContext *DCtx = D->getDeclContext()->getRedeclContext();
137  return AllowInlineNamespace ? Ctx->InEnclosingNamespaceSetOf(DCtx)
138  : Ctx->Equals(DCtx);
139 }
140 
141 /// AddDecl - Link the decl to its shadowed decl chain.
144  if (IdentifierInfo *II = Name.getAsIdentifierInfo())
145  updatingIdentifier(*II);
146 
147  void *Ptr = Name.getFETokenInfo<void>();
148 
149  if (!Ptr) {
150  Name.setFETokenInfo(D);
151  return;
152  }
153 
154  IdDeclInfo *IDI;
155 
156  if (isDeclPtr(Ptr)) {
157  Name.setFETokenInfo(nullptr);
158  IDI = &(*IdDeclInfos)[Name];
159  NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
160  IDI->AddDecl(PrevD);
161  } else
162  IDI = toIdDeclInfo(Ptr);
163 
164  IDI->AddDecl(D);
165 }
166 
169  if (IdentifierInfo *II = Name.getAsIdentifierInfo())
170  updatingIdentifier(*II);
171 
172  void *Ptr = Name.getFETokenInfo<void>();
173 
174  if (!Ptr) {
175  AddDecl(D);
176  return;
177  }
178 
179  if (isDeclPtr(Ptr)) {
180  // We only have a single declaration: insert before or after it,
181  // as appropriate.
182  if (Pos == iterator()) {
183  // Add the new declaration before the existing declaration.
184  NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
185  RemoveDecl(PrevD);
186  AddDecl(D);
187  AddDecl(PrevD);
188  } else {
189  // Add new declaration after the existing declaration.
190  AddDecl(D);
191  }
192 
193  return;
194  }
195 
196  // General case: insert the declaration at the appropriate point in the
197  // list, which already has at least two elements.
198  IdDeclInfo *IDI = toIdDeclInfo(Ptr);
199  if (Pos.isIterator()) {
200  IDI->InsertDecl(Pos.getIterator() + 1, D);
201  } else
202  IDI->InsertDecl(IDI->decls_begin(), D);
203 }
204 
205 /// RemoveDecl - Unlink the decl from its shadowed decl chain.
206 /// The decl must already be part of the decl chain.
208  assert(D && "null param passed");
210  if (IdentifierInfo *II = Name.getAsIdentifierInfo())
211  updatingIdentifier(*II);
212 
213  void *Ptr = Name.getFETokenInfo<void>();
214 
215  assert(Ptr && "Didn't find this decl on its identifier's chain!");
216 
217  if (isDeclPtr(Ptr)) {
218  assert(D == Ptr && "Didn't find this decl on its identifier's chain!");
219  Name.setFETokenInfo(nullptr);
220  return;
221  }
222 
223  return toIdDeclInfo(Ptr)->RemoveDecl(D);
224 }
225 
226 /// begin - Returns an iterator for decls with name 'Name'.
229  if (IdentifierInfo *II = Name.getAsIdentifierInfo())
230  readingIdentifier(*II);
231 
232  void *Ptr = Name.getFETokenInfo<void>();
233  if (!Ptr) return end();
234 
235  if (isDeclPtr(Ptr))
236  return iterator(static_cast<NamedDecl*>(Ptr));
237 
238  IdDeclInfo *IDI = toIdDeclInfo(Ptr);
239 
240  IdDeclInfo::DeclsTy::iterator I = IDI->decls_end();
241  if (I != IDI->decls_begin())
242  return iterator(I-1);
243  // No decls found.
244  return end();
245 }
246 
247 namespace {
249  DMK_Different,
250  DMK_Replace,
251  DMK_Ignore
252  };
253 }
254 
255 /// \brief Compare two declarations to see whether they are different or,
256 /// if they are the same, whether the new declaration should replace the
257 /// existing declaration.
259  // If the declarations are identical, ignore the new one.
260  if (Existing == New)
261  return DMK_Ignore;
262 
263  // If the declarations have different kinds, they're obviously different.
264  if (Existing->getKind() != New->getKind())
265  return DMK_Different;
266 
267  // If the declarations are redeclarations of each other, keep the newest one.
268  if (Existing->getCanonicalDecl() == New->getCanonicalDecl()) {
269  // If we're adding an imported declaration, don't replace another imported
270  // declaration.
271  if (Existing->isFromASTFile() && New->isFromASTFile())
272  return DMK_Different;
273 
274  // If either of these is the most recent declaration, use it.
275  Decl *MostRecent = Existing->getMostRecentDecl();
276  if (Existing == MostRecent)
277  return DMK_Ignore;
278 
279  if (New == MostRecent)
280  return DMK_Replace;
281 
282  // If the existing declaration is somewhere in the previous declaration
283  // chain of the new declaration, then prefer the new declaration.
284  for (auto RD : New->redecls()) {
285  if (RD == Existing)
286  return DMK_Replace;
287 
288  if (RD->isCanonicalDecl())
289  break;
290  }
291 
292  return DMK_Ignore;
293  }
294 
295  return DMK_Different;
296 }
297 
299  if (IdentifierInfo *II = Name.getAsIdentifierInfo())
300  readingIdentifier(*II);
301 
302  void *Ptr = Name.getFETokenInfo<void>();
303 
304  if (!Ptr) {
305  Name.setFETokenInfo(D);
306  return true;
307  }
308 
309  IdDeclInfo *IDI;
310 
311  if (isDeclPtr(Ptr)) {
312  NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
313 
314  switch (compareDeclarations(PrevD, D)) {
315  case DMK_Different:
316  break;
317 
318  case DMK_Ignore:
319  return false;
320 
321  case DMK_Replace:
322  Name.setFETokenInfo(D);
323  return true;
324  }
325 
326  Name.setFETokenInfo(nullptr);
327  IDI = &(*IdDeclInfos)[Name];
328 
329  // If the existing declaration is not visible in translation unit scope,
330  // then add the new top-level declaration first.
331  if (!PrevD->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
332  IDI->AddDecl(D);
333  IDI->AddDecl(PrevD);
334  } else {
335  IDI->AddDecl(PrevD);
336  IDI->AddDecl(D);
337  }
338  return true;
339  }
340 
341  IDI = toIdDeclInfo(Ptr);
342 
343  // See whether this declaration is identical to any existing declarations.
344  // If not, find the right place to insert it.
345  for (IdDeclInfo::DeclsTy::iterator I = IDI->decls_begin(),
346  IEnd = IDI->decls_end();
347  I != IEnd; ++I) {
348 
349  switch (compareDeclarations(*I, D)) {
350  case DMK_Different:
351  break;
352 
353  case DMK_Ignore:
354  return false;
355 
356  case DMK_Replace:
357  *I = D;
358  return true;
359  }
360 
361  if (!(*I)->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
362  // We've found a declaration that is not visible from the translation
363  // unit (it's in an inner scope). Insert our declaration here.
364  IDI->InsertDecl(I, D);
365  return true;
366  }
367  }
368 
369  // Add the declaration to the end.
370  IDI->AddDecl(D);
371  return true;
372 }
373 
374 void IdentifierResolver::readingIdentifier(IdentifierInfo &II) {
375  if (II.isOutOfDate())
377 }
378 
379 void IdentifierResolver::updatingIdentifier(IdentifierInfo &II) {
380  if (II.isOutOfDate())
382 
383  if (II.isFromAST())
385 }
386 
387 //===----------------------------------------------------------------------===//
388 // IdDeclInfoMap Implementation
389 //===----------------------------------------------------------------------===//
390 
391 /// Returns the IdDeclInfo associated to the DeclarationName.
392 /// It creates a new IdDeclInfo if one was not created before for this id.
393 IdentifierResolver::IdDeclInfo &
395  void *Ptr = Name.getFETokenInfo<void>();
396 
397  if (Ptr) return *toIdDeclInfo(Ptr);
398 
399  if (CurIndex == POOL_SIZE) {
400  CurPool = new IdDeclInfoPool(CurPool);
401  CurIndex = 0;
402  }
403  IdDeclInfo *IDI = &CurPool->Pool[CurIndex];
404  Name.setFETokenInfo(reinterpret_cast<void*>(
405  reinterpret_cast<uintptr_t>(IDI) | 0x1)
406  );
407  ++CurIndex;
408  return *IDI;
409 }
410 
411 void IdentifierResolver::iterator::incrementSlowCase() {
412  NamedDecl *D = **this;
413  void *InfoPtr = D->getDeclName().getFETokenInfo<void>();
414  assert(!isDeclPtr(InfoPtr) && "Decl with wrong id ?");
415  IdDeclInfo *Info = toIdDeclInfo(InfoPtr);
416 
417  BaseIter I = getIterator();
418  if (I != Info->decls_begin())
419  *this = iterator(I-1);
420  else // No more decls.
421  *this = iterator();
422 }
unsigned getFlags() const
getFlags - Return the flags for this scope.
Definition: Scope.h:210
bool isTransparentContext() const
isTransparentContext - Determines whether this context is a "transparent" context, meaning that the members declared in this context are semantically declared in the nearest enclosing non-transparent (opaque) context but are lexically declared in this context.
Definition: DeclBase.cpp:954
ExternalPreprocessorSource * getExternalSource() const
Definition: Preprocessor.h:711
bool tryAddTopLevelDecl(NamedDecl *D, DeclarationName Name)
Try to add the given declaration to the top level scope, if it (or a redeclaration of it) hasn't alre...
const Scope * getParent() const
getParent - Return the scope that this is nested in.
Definition: Scope.h:218
StringRef P
IdentifierInfo * getAsIdentifierInfo() const
getAsIdentifierInfo - Retrieve the IdentifierInfo * stored in this declaration name, or NULL if this declaration name isn't a simple identifier.
iterator begin(DeclarationName Name)
begin - Returns an iterator for decls with the name 'Name'.
One of these records is kept for each identifier that is lexed.
class LLVM_ALIGNAS(8) DependentTemplateSpecializationType const IdentifierInfo * Name
Represents a template specialization type whose template cannot be resolved, e.g. ...
Definition: Type.h:4549
bool isFromAST() const
Return true if the identifier in its current state was loaded from an AST file.
iterator end()
end - Returns an iterator that has 'finished'.
The controlling scope in a if/switch/while/for statement.
Definition: Scope.h:61
void RemoveDecl(NamedDecl *D)
RemoveDecl - Unlink the decl from its shadowed decl chain.
bool isOutOfDate() const
Determine whether the information for this identifier is out of date with respect to the external sou...
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:39
detail::InMemoryDirectory::const_iterator I
IdDeclInfoMap - Associates IdDeclInfos with declaration names.
static DeclMatchKind compareDeclarations(NamedDecl *Existing, NamedDecl *New)
Compare two declarations to see whether they are different or, if they are the same, whether the new declaration should replace the existing declaration.
Defines the clang::LangOptions interface.
bool isDeclScope(Decl *D)
isDeclScope - Return true if this is the scope that the specified decl is declared in...
Definition: Scope.h:309
Defines the clang::Preprocessor interface.
bool isFunctionOrMethod() const
Definition: DeclBase.h:1263
DeclarationName getDeclName() const
getDeclName - Get the actual, stored name of the declaration, which may be a special name...
Definition: Decl.h:258
DeclContext * getEntity() const
Definition: Scope.h:313
SmallVectorImpl< AnnotatedLine * >::const_iterator Next
const TemplateArgument * iterator
Definition: Type.h:4233
void setFETokenInfoChangedSinceDeserialization()
Note that the frontend token information for this identifier has changed since it was loaded from an ...
bool InEnclosingNamespaceSetOf(const DeclContext *NS) const
Test if this context is part of the enclosing namespace set of the context NS, as defined in C++0x [n...
Definition: DeclBase.cpp:1561
IdDeclInfo & operator[](DeclarationName Name)
Returns the IdDeclInfo associated to the DeclarationName.
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1135
IdentifierResolver(Preprocessor &PP)
DeclarationName - The name of a declaration.
bool isDeclInScope(Decl *D, DeclContext *Ctx, Scope *S=nullptr, bool AllowInlineNamespace=false) const
isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true if 'D' is in Scope 'S'...
void InsertDeclAfter(iterator Pos, NamedDecl *D)
Insert the given declaration after the given iterator position.
This is the scope for a function-level C++ try or catch scope.
Definition: Scope.h:103
void AddDecl(NamedDecl *D)
AddDecl - Link the decl to its shadowed decl chain.
virtual void updateOutOfDateIdentifier(IdentifierInfo &II)=0
Update an out-of-date identifier.
DeclContext * getRedeclContext()
getRedeclContext - Retrieve the context in which an entity conflicts with other entities of the same ...
Definition: DeclBase.cpp:1534
bool isFunctionPrototypeScope() const
isFunctionPrototypeScope - Return true if this scope is a function prototype scope.
Definition: Scope.h:371
IdDeclInfo::DeclsTy::iterator BaseIter
bool Equals(const DeclContext *DC) const
Determine whether this declaration context is equivalent to the declaration context DC...
Definition: DeclBase.h:1330
NamedDecl * getMostRecentDecl()
Definition: Decl.h:401
NamedDecl - This represents a decl with a name.
Definition: Decl.h:213
T * getFETokenInfo() const
getFETokenInfo/setFETokenInfo - The language front-end is allowed to associate arbitrary metadata wit...
iterator - Iterate over the decls of a specified declaration name.
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:97