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 "IdentifierResolver.h"
16 #include "clang/Basic/LangOptions.h"
17 #include <list>
18 #include <vector>
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 VECTOR_SIZE = 512;
31   // Holds vectors of IdDeclInfos that serve as 'pools'.
32   // New vectors are added when the current one is full.
33   std::list< std::vector<IdDeclInfo> > IDIVecs;
34   unsigned int CurIndex;
35 
36 public:
37   IdDeclInfoMap() : CurIndex(VECTOR_SIZE) {}
38 
39   /// Returns the IdDeclInfo associated to the DeclarationName.
40   /// It creates a new IdDeclInfo if one was not created before for this id.
41   IdDeclInfo &operator[](DeclarationName Name);
42 };
43 
44 
45 //===----------------------------------------------------------------------===//
46 // IdDeclInfo Implementation
47 //===----------------------------------------------------------------------===//
48 
49 /// AddShadowed - Add a decl by putting it directly above the 'Shadow' decl.
50 /// Later lookups will find the 'Shadow' decl first. The 'Shadow' decl must
51 /// be already added to the scope chain and must be in the same context as
52 /// the decl that we want to add.
53 void IdentifierResolver::IdDeclInfo::AddShadowed(NamedDecl *D,
54                                                  NamedDecl *Shadow) {
55   for (DeclsTy::iterator I = Decls.end(); I != Decls.begin(); --I) {
56     if (Shadow == *(I-1)) {
57       Decls.insert(I-1, D);
58       return;
59     }
60   }
61 
62   assert(0 && "Shadow wasn't in scope chain!");
63 }
64 
65 /// RemoveDecl - Remove the decl from the scope chain.
66 /// The decl must already be part of the decl chain.
67 void IdentifierResolver::IdDeclInfo::RemoveDecl(NamedDecl *D) {
68   for (DeclsTy::iterator I = Decls.end(); I != Decls.begin(); --I) {
69     if (D == *(I-1)) {
70       Decls.erase(I-1);
71       return;
72     }
73   }
74 
75   assert(0 && "Didn't find this decl on its identifier's chain!");
76 }
77 
78 bool
79 IdentifierResolver::IdDeclInfo::ReplaceDecl(NamedDecl *Old, NamedDecl *New) {
80   for (DeclsTy::iterator I = Decls.end(); I != Decls.begin(); --I) {
81     if (Old == *(I-1)) {
82       *(I - 1) = New;
83       return true;
84     }
85   }
86 
87   return false;
88 }
89 
90 
91 //===----------------------------------------------------------------------===//
92 // IdentifierResolver Implementation
93 //===----------------------------------------------------------------------===//
94 
95 IdentifierResolver::IdentifierResolver(const LangOptions &langOpt)
96     : LangOpt(langOpt), IdDeclInfos(new IdDeclInfoMap) {
97 }
98 IdentifierResolver::~IdentifierResolver() {
99   delete IdDeclInfos;
100 }
101 
102 /// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
103 /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
104 /// true if 'D' belongs to the given declaration context.
105 bool IdentifierResolver::isDeclInScope(Decl *D, DeclContext *Ctx,
106                                        ASTContext &Context, Scope *S) const {
107   Ctx = Ctx->getLookupContext();
108 
109   if (Ctx->isFunctionOrMethod()) {
110     // Ignore the scopes associated within transparent declaration contexts.
111     while (S->getEntity() &&
112            ((DeclContext *)S->getEntity())->isTransparentContext())
113       S = S->getParent();
114 
115     if (S->isDeclScope(Action::DeclPtrTy::make(D)))
116       return true;
117     if (LangOpt.CPlusPlus) {
118       // C++ 3.3.2p3:
119       // The name declared in a catch exception-declaration is local to the
120       // handler and shall not be redeclared in the outermost block of the
121       // handler.
122       // C++ 3.3.2p4:
123       // Names declared in the for-init-statement, and in the condition of if,
124       // while, for, and switch statements are local to the if, while, for, or
125       // switch statement (including the controlled statement), and shall not be
126       // redeclared in a subsequent condition of that statement nor in the
127       // outermost block (or, for the if statement, any of the outermost blocks)
128       // of the controlled statement.
129       //
130       assert(S->getParent() && "No TUScope?");
131       if (S->getParent()->getFlags() & Scope::ControlScope)
132         return S->getParent()->isDeclScope(Action::DeclPtrTy::make(D));
133     }
134     return false;
135   }
136 
137   return D->getDeclContext()->getLookupContext()->Equals(Ctx);
138 }
139 
140 /// AddDecl - Link the decl to its shadowed decl chain.
141 void IdentifierResolver::AddDecl(NamedDecl *D) {
142   DeclarationName Name = D->getDeclName();
143   void *Ptr = Name.getFETokenInfo<void>();
144 
145   if (!Ptr) {
146     Name.setFETokenInfo(D);
147     return;
148   }
149 
150   IdDeclInfo *IDI;
151 
152   if (isDeclPtr(Ptr)) {
153     Name.setFETokenInfo(NULL);
154     IDI = &(*IdDeclInfos)[Name];
155     NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
156     IDI->AddDecl(PrevD);
157   } else
158     IDI = toIdDeclInfo(Ptr);
159 
160   IDI->AddDecl(D);
161 }
162 
163 /// AddShadowedDecl - Link the decl to its shadowed decl chain putting it
164 /// after the decl that the iterator points to, thus the 'Shadow' decl will be
165 /// encountered before the 'D' decl.
166 void IdentifierResolver::AddShadowedDecl(NamedDecl *D, NamedDecl *Shadow) {
167   assert(D->getDeclName() == Shadow->getDeclName() && "Different ids!");
168 
169   DeclarationName Name = D->getDeclName();
170   void *Ptr = Name.getFETokenInfo<void>();
171   assert(Ptr && "No decl from Ptr ?");
172 
173   IdDeclInfo *IDI;
174 
175   if (isDeclPtr(Ptr)) {
176     Name.setFETokenInfo(NULL);
177     IDI = &(*IdDeclInfos)[Name];
178     NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
179     assert(PrevD == Shadow && "Invalid shadow decl ?");
180     IDI->AddDecl(D);
181     IDI->AddDecl(PrevD);
182     return;
183   }
184 
185   IDI = toIdDeclInfo(Ptr);
186   IDI->AddShadowed(D, Shadow);
187 }
188 
189 /// RemoveDecl - Unlink the decl from its shadowed decl chain.
190 /// The decl must already be part of the decl chain.
191 void IdentifierResolver::RemoveDecl(NamedDecl *D) {
192   assert(D && "null param passed");
193   DeclarationName Name = D->getDeclName();
194   void *Ptr = Name.getFETokenInfo<void>();
195 
196   assert(Ptr && "Didn't find this decl on its identifier's chain!");
197 
198   if (isDeclPtr(Ptr)) {
199     assert(D == Ptr && "Didn't find this decl on its identifier's chain!");
200     Name.setFETokenInfo(NULL);
201     return;
202   }
203 
204   return toIdDeclInfo(Ptr)->RemoveDecl(D);
205 }
206 
207 bool IdentifierResolver::ReplaceDecl(NamedDecl *Old, NamedDecl *New) {
208   assert(Old->getDeclName() == New->getDeclName() &&
209          "Cannot replace a decl with another decl of a different name");
210 
211   DeclarationName Name = Old->getDeclName();
212   void *Ptr = Name.getFETokenInfo<void>();
213 
214   if (!Ptr)
215     return false;
216 
217   if (isDeclPtr(Ptr)) {
218     if (Ptr == Old) {
219       Name.setFETokenInfo(New);
220       return true;
221     }
222     return false;
223   }
224 
225   return toIdDeclInfo(Ptr)->ReplaceDecl(Old, New);
226 }
227 
228 /// begin - Returns an iterator for decls with name 'Name'.
229 IdentifierResolver::iterator
230 IdentifierResolver::begin(DeclarationName Name) {
231   void *Ptr = Name.getFETokenInfo<void>();
232   if (!Ptr) return end();
233 
234   if (isDeclPtr(Ptr))
235     return iterator(static_cast<NamedDecl*>(Ptr));
236 
237   IdDeclInfo *IDI = toIdDeclInfo(Ptr);
238 
239   IdDeclInfo::DeclsTy::iterator I = IDI->decls_end();
240   if (I != IDI->decls_begin())
241     return iterator(I-1);
242   // No decls found.
243   return end();
244 }
245 
246 void IdentifierResolver::AddDeclToIdentifierChain(IdentifierInfo *II,
247                                                   NamedDecl *D) {
248   void *Ptr = II->getFETokenInfo<void>();
249 
250   if (!Ptr) {
251     II->setFETokenInfo(D);
252     return;
253   }
254 
255   IdDeclInfo *IDI;
256 
257   if (isDeclPtr(Ptr)) {
258     II->setFETokenInfo(NULL);
259     IDI = &(*IdDeclInfos)[II];
260     NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
261     IDI->AddDecl(PrevD);
262   } else
263     IDI = toIdDeclInfo(Ptr);
264 
265   IDI->AddDecl(D);
266 }
267 
268 //===----------------------------------------------------------------------===//
269 // IdDeclInfoMap Implementation
270 //===----------------------------------------------------------------------===//
271 
272 /// Returns the IdDeclInfo associated to the DeclarationName.
273 /// It creates a new IdDeclInfo if one was not created before for this id.
274 IdentifierResolver::IdDeclInfo &
275 IdentifierResolver::IdDeclInfoMap::operator[](DeclarationName Name) {
276   void *Ptr = Name.getFETokenInfo<void>();
277 
278   if (Ptr) return *toIdDeclInfo(Ptr);
279 
280   if (CurIndex == VECTOR_SIZE) {
281     // Add a IdDeclInfo vector 'pool'
282     IDIVecs.push_back(std::vector<IdDeclInfo>());
283     // Fill the vector
284     IDIVecs.back().resize(VECTOR_SIZE);
285     CurIndex = 0;
286   }
287   IdDeclInfo *IDI = &IDIVecs.back()[CurIndex];
288   Name.setFETokenInfo(reinterpret_cast<void*>(
289                               reinterpret_cast<uintptr_t>(IDI) | 0x1)
290                                                                      );
291   ++CurIndex;
292   return *IDI;
293 }
294