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 
15 #include "clang/Sema/IdentifierResolver.h"
16 #include "clang/Sema/Scope.h"
17 #include "clang/AST/Decl.h"
18 #include "clang/Basic/LangOptions.h"
19 
20 using namespace clang;
21 
22 //===----------------------------------------------------------------------===//
23 // IdDeclInfoMap class
24 //===----------------------------------------------------------------------===//
25 
26 /// IdDeclInfoMap - Associates IdDeclInfos with declaration names.
27 /// Allocates 'pools' (vectors of IdDeclInfos) to avoid allocating each
28 /// individual IdDeclInfo to heap.
29 class IdentifierResolver::IdDeclInfoMap {
30   static const unsigned int POOL_SIZE = 512;
31 
32   /// We use our own linked-list implementation because it is sadly
33   /// impossible to add something to a pre-C++0x STL container without
34   /// a completely unnecessary copy.
35   struct IdDeclInfoPool {
36     IdDeclInfoPool(IdDeclInfoPool *Next) : Next(Next) {}
37 
38     IdDeclInfoPool *Next;
39     IdDeclInfo Pool[POOL_SIZE];
40   };
41 
42   IdDeclInfoPool *CurPool;
43   unsigned int CurIndex;
44 
45 public:
46   IdDeclInfoMap() : CurPool(0), CurIndex(POOL_SIZE) {}
47 
48   ~IdDeclInfoMap() {
49     IdDeclInfoPool *Cur = CurPool;
50     while (IdDeclInfoPool *P = Cur) {
51       Cur = Cur->Next;
52       delete P;
53     }
54   }
55 
56   /// Returns the IdDeclInfo associated to the DeclarationName.
57   /// It creates a new IdDeclInfo if one was not created before for this id.
58   IdDeclInfo &operator[](DeclarationName Name);
59 };
60 
61 
62 //===----------------------------------------------------------------------===//
63 // IdDeclInfo Implementation
64 //===----------------------------------------------------------------------===//
65 
66 /// RemoveDecl - Remove the decl from the scope chain.
67 /// The decl must already be part of the decl chain.
68 void IdentifierResolver::IdDeclInfo::RemoveDecl(NamedDecl *D) {
69   for (DeclsTy::iterator I = Decls.end(); I != Decls.begin(); --I) {
70     if (D == *(I-1)) {
71       Decls.erase(I-1);
72       return;
73     }
74   }
75 
76   assert(0 && "Didn't find this decl on its identifier's chain!");
77 }
78 
79 bool
80 IdentifierResolver::IdDeclInfo::ReplaceDecl(NamedDecl *Old, NamedDecl *New) {
81   for (DeclsTy::iterator I = Decls.end(); I != Decls.begin(); --I) {
82     if (Old == *(I-1)) {
83       *(I - 1) = New;
84       return true;
85     }
86   }
87 
88   return false;
89 }
90 
91 
92 //===----------------------------------------------------------------------===//
93 // IdentifierResolver Implementation
94 //===----------------------------------------------------------------------===//
95 
96 IdentifierResolver::IdentifierResolver(const LangOptions &langOpt)
97     : LangOpt(langOpt), IdDeclInfos(new IdDeclInfoMap) {
98 }
99 IdentifierResolver::~IdentifierResolver() {
100   delete IdDeclInfos;
101 }
102 
103 /// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
104 /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
105 /// true if 'D' belongs to the given declaration context.
106 bool IdentifierResolver::isDeclInScope(Decl *D, DeclContext *Ctx,
107                                        ASTContext &Context, Scope *S) const {
108   Ctx = Ctx->getRedeclContext();
109 
110   if (Ctx->isFunctionOrMethod()) {
111     // Ignore the scopes associated within transparent declaration contexts.
112     while (S->getEntity() &&
113            ((DeclContext *)S->getEntity())->isTransparentContext())
114       S = S->getParent();
115 
116     if (S->isDeclScope(D))
117       return true;
118     if (LangOpt.CPlusPlus) {
119       // C++ 3.3.2p3:
120       // The name declared in a catch exception-declaration is local to the
121       // handler and shall not be redeclared in the outermost block of the
122       // handler.
123       // C++ 3.3.2p4:
124       // Names declared in the for-init-statement, and in the condition of if,
125       // while, for, and switch statements are local to the if, while, for, or
126       // switch statement (including the controlled statement), and shall not be
127       // redeclared in a subsequent condition of that statement nor in the
128       // outermost block (or, for the if statement, any of the outermost blocks)
129       // of the controlled statement.
130       //
131       assert(S->getParent() && "No TUScope?");
132       if (S->getParent()->getFlags() & Scope::ControlScope)
133         return S->getParent()->isDeclScope(D);
134     }
135     return false;
136   }
137 
138   return D->getDeclContext()->getRedeclContext()->Equals(Ctx);
139 }
140 
141 /// AddDecl - Link the decl to its shadowed decl chain.
142 void IdentifierResolver::AddDecl(NamedDecl *D) {
143   DeclarationName Name = D->getDeclName();
144   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
145     II->setIsFromAST(false);
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(NULL);
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 
167 /// RemoveDecl - Unlink the decl from its shadowed decl chain.
168 /// The decl must already be part of the decl chain.
169 void IdentifierResolver::RemoveDecl(NamedDecl *D) {
170   assert(D && "null param passed");
171   DeclarationName Name = D->getDeclName();
172   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
173     II->setIsFromAST(false);
174 
175   void *Ptr = Name.getFETokenInfo<void>();
176 
177   assert(Ptr && "Didn't find this decl on its identifier's chain!");
178 
179   if (isDeclPtr(Ptr)) {
180     assert(D == Ptr && "Didn't find this decl on its identifier's chain!");
181     Name.setFETokenInfo(NULL);
182     return;
183   }
184 
185   return toIdDeclInfo(Ptr)->RemoveDecl(D);
186 }
187 
188 bool IdentifierResolver::ReplaceDecl(NamedDecl *Old, NamedDecl *New) {
189   assert(Old->getDeclName() == New->getDeclName() &&
190          "Cannot replace a decl with another decl of a different name");
191 
192   DeclarationName Name = Old->getDeclName();
193   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
194     II->setIsFromAST(false);
195 
196   void *Ptr = Name.getFETokenInfo<void>();
197 
198   if (!Ptr)
199     return false;
200 
201   if (isDeclPtr(Ptr)) {
202     if (Ptr == Old) {
203       Name.setFETokenInfo(New);
204       return true;
205     }
206     return false;
207   }
208 
209   return toIdDeclInfo(Ptr)->ReplaceDecl(Old, New);
210 }
211 
212 /// begin - Returns an iterator for decls with name 'Name'.
213 IdentifierResolver::iterator
214 IdentifierResolver::begin(DeclarationName Name) {
215   void *Ptr = Name.getFETokenInfo<void>();
216   if (!Ptr) return end();
217 
218   if (isDeclPtr(Ptr))
219     return iterator(static_cast<NamedDecl*>(Ptr));
220 
221   IdDeclInfo *IDI = toIdDeclInfo(Ptr);
222 
223   IdDeclInfo::DeclsTy::iterator I = IDI->decls_end();
224   if (I != IDI->decls_begin())
225     return iterator(I-1);
226   // No decls found.
227   return end();
228 }
229 
230 void IdentifierResolver::AddDeclToIdentifierChain(IdentifierInfo *II,
231                                                   NamedDecl *D) {
232   II->setIsFromAST(false);
233   void *Ptr = II->getFETokenInfo<void>();
234 
235   if (!Ptr) {
236     II->setFETokenInfo(D);
237     return;
238   }
239 
240   IdDeclInfo *IDI;
241 
242   if (isDeclPtr(Ptr)) {
243     II->setFETokenInfo(NULL);
244     IDI = &(*IdDeclInfos)[II];
245     NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
246     IDI->AddDecl(PrevD);
247   } else
248     IDI = toIdDeclInfo(Ptr);
249 
250   IDI->AddDecl(D);
251 }
252 
253 //===----------------------------------------------------------------------===//
254 // IdDeclInfoMap Implementation
255 //===----------------------------------------------------------------------===//
256 
257 /// Returns the IdDeclInfo associated to the DeclarationName.
258 /// It creates a new IdDeclInfo if one was not created before for this id.
259 IdentifierResolver::IdDeclInfo &
260 IdentifierResolver::IdDeclInfoMap::operator[](DeclarationName Name) {
261   void *Ptr = Name.getFETokenInfo<void>();
262 
263   if (Ptr) return *toIdDeclInfo(Ptr);
264 
265   if (CurIndex == POOL_SIZE) {
266     CurPool = new IdDeclInfoPool(CurPool);
267     CurIndex = 0;
268   }
269   IdDeclInfo *IDI = &CurPool->Pool[CurIndex];
270   Name.setFETokenInfo(reinterpret_cast<void*>(
271                               reinterpret_cast<uintptr_t>(IDI) | 0x1)
272                                                                      );
273   ++CurIndex;
274   return *IDI;
275 }
276 
277 void IdentifierResolver::iterator::incrementSlowCase() {
278   NamedDecl *D = **this;
279   void *InfoPtr = D->getDeclName().getFETokenInfo<void>();
280   assert(!isDeclPtr(InfoPtr) && "Decl with wrong id ?");
281   IdDeclInfo *Info = toIdDeclInfo(InfoPtr);
282 
283   BaseIter I = getIterator();
284   if (I != Info->decls_begin())
285     *this = iterator(I-1);
286   else // No more decls.
287     *this = iterator();
288 }
289