Scope.h revision 3a2b7a18a4504f39e3ded0d2b5749c5c80b8b9b5 
1//===--- Scope.h - Scope interface ------------------------------*- 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 defines the Scope interface.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_SEMA_SCOPE_H
15#define LLVM_CLANG_SEMA_SCOPE_H
16
17#include "clang/Basic/Diagnostic.h"
18#include "llvm/ADT/SmallPtrSet.h"
19#include "llvm/ADT/SmallVector.h"
20
21namespace clang {
22
23class Decl;
24class UsingDirectiveDecl;
25
26/// Scope - A scope is a transient data structure that is used while parsing the
27/// program.  It assists with resolving identifiers to the appropriate
28/// declaration.
29///
30class Scope {
31public:
32  /// ScopeFlags - These are bitfields that are or'd together when creating a
33  /// scope, which defines the sorts of things the scope contains.
34  enum ScopeFlags {
35    /// \brief This indicates that the scope corresponds to a function, which
36    /// means that labels are set here.
37    FnScope       = 0x01,
38
39    /// \brief This is a while, do, switch, for, etc that can have break
40    /// statements embedded into it.
41    BreakScope    = 0x02,
42
43    /// \brief This is a while, do, for, which can have continue statements
44    /// embedded into it.
45    ContinueScope = 0x04,
46
47    /// \brief This is a scope that can contain a declaration.  Some scopes
48    /// just contain loop constructs but don't contain decls.
49    DeclScope = 0x08,
50
51    /// \brief The controlling scope in a if/switch/while/for statement.
52    ControlScope = 0x10,
53
54    /// \brief The scope of a struct/union/class definition.
55    ClassScope = 0x20,
56
57    /// \brief This is a scope that corresponds to a block/closure object.
58    /// Blocks serve as top-level scopes for some objects like labels, they
59    /// also prevent things like break and continue.  BlockScopes always have
60    /// the FnScope and DeclScope flags set as well.
61    BlockScope = 0x40,
62
63    /// \brief This is a scope that corresponds to the
64    /// template parameters of a C++ template. Template parameter
65    /// scope starts at the 'template' keyword and ends when the
66    /// template declaration ends.
67    TemplateParamScope = 0x80,
68
69    /// \brief This is a scope that corresponds to the
70    /// parameters within a function prototype.
71    FunctionPrototypeScope = 0x100,
72
73    /// \brief This is a scope that corresponds to the parameters within
74    /// a function prototype for a function declaration (as opposed to any
75    /// other kind of function declarator). Always has FunctionPrototypeScope
76    /// set as well.
77    FunctionDeclarationScope = 0x200,
78
79    /// \brief This is a scope that corresponds to the Objective-C
80    /// \@catch statement.
81    AtCatchScope = 0x400,
82
83    /// \brief This scope corresponds to an Objective-C method body.
84    /// It always has FnScope and DeclScope set as well.
85    ObjCMethodScope = 0x800,
86
87    /// \brief This is a scope that corresponds to a switch statement.
88    SwitchScope = 0x1000,
89
90    /// \brief This is the scope of a C++ try statement.
91    TryScope = 0x2000,
92
93    /// \brief This is the scope for a function-level C++ try or catch scope.
94    FnTryCatchScope = 0x4000
95  };
96private:
97  /// The parent scope for this scope.  This is null for the translation-unit
98  /// scope.
99  Scope *AnyParent;
100
101  /// Depth - This is the depth of this scope.  The translation-unit scope has
102  /// depth 0.
103  unsigned short Depth;
104
105  /// Flags - This contains a set of ScopeFlags, which indicates how the scope
106  /// interrelates with other control flow statements.
107  unsigned short Flags;
108
109  /// PrototypeDepth - This is the number of function prototype scopes
110  /// enclosing this scope, including this scope.
111  unsigned short PrototypeDepth;
112
113  /// PrototypeIndex - This is the number of parameters currently
114  /// declared in this scope.
115  unsigned short PrototypeIndex;
116
117  /// FnParent - If this scope has a parent scope that is a function body, this
118  /// pointer is non-null and points to it.  This is used for label processing.
119  Scope *FnParent;
120
121  /// BreakParent/ContinueParent - This is a direct link to the innermost
122  /// BreakScope/ContinueScope which contains the contents of this scope
123  /// for control flow purposes (and might be this scope itself), or null
124  /// if there is no such scope.
125  Scope *BreakParent, *ContinueParent;
126
127  /// BlockParent - This is a direct link to the immediately containing
128  /// BlockScope if this scope is not one, or null if there is none.
129  Scope *BlockParent;
130
131  /// TemplateParamParent - This is a direct link to the
132  /// immediately containing template parameter scope. In the
133  /// case of nested templates, template parameter scopes can have
134  /// other template parameter scopes as parents.
135  Scope *TemplateParamParent;
136
137  /// DeclsInScope - This keeps track of all declarations in this scope.  When
138  /// the declaration is added to the scope, it is set as the current
139  /// declaration for the identifier in the IdentifierTable.  When the scope is
140  /// popped, these declarations are removed from the IdentifierTable's notion
141  /// of current declaration.  It is up to the current Action implementation to
142  /// implement these semantics.
143  typedef llvm::SmallPtrSet<Decl *, 32> DeclSetTy;
144  DeclSetTy DeclsInScope;
145
146  /// Entity - The entity with which this scope is associated. For
147  /// example, the entity of a class scope is the class itself, the
148  /// entity of a function scope is a function, etc. This field is
149  /// maintained by the Action implementation.
150  void *Entity;
151
152  typedef SmallVector<UsingDirectiveDecl *, 2> UsingDirectivesTy;
153  UsingDirectivesTy UsingDirectives;
154
155  /// \brief Used to determine if errors occurred in this scope.
156  DiagnosticErrorTrap ErrorTrap;
157
158public:
159  Scope(Scope *Parent, unsigned ScopeFlags, DiagnosticsEngine &Diag)
160    : ErrorTrap(Diag) {
161    Init(Parent, ScopeFlags);
162  }
163
164  /// getFlags - Return the flags for this scope.
165  ///
166  unsigned getFlags() const { return Flags; }
167  void setFlags(unsigned F) { Flags = F; }
168
169  /// isBlockScope - Return true if this scope correspond to a closure.
170  bool isBlockScope() const { return Flags & BlockScope; }
171
172  /// getParent - Return the scope that this is nested in.
173  ///
174  const Scope *getParent() const { return AnyParent; }
175  Scope *getParent() { return AnyParent; }
176
177  /// getFnParent - Return the closest scope that is a function body.
178  ///
179  const Scope *getFnParent() const { return FnParent; }
180  Scope *getFnParent() { return FnParent; }
181
182  /// getContinueParent - Return the closest scope that a continue statement
183  /// would be affected by.
184  Scope *getContinueParent() {
185    return ContinueParent;
186  }
187
188  const Scope *getContinueParent() const {
189    return const_cast<Scope*>(this)->getContinueParent();
190  }
191
192  /// getBreakParent - Return the closest scope that a break statement
193  /// would be affected by.
194  Scope *getBreakParent() {
195    return BreakParent;
196  }
197  const Scope *getBreakParent() const {
198    return const_cast<Scope*>(this)->getBreakParent();
199  }
200
201  Scope *getBlockParent() { return BlockParent; }
202  const Scope *getBlockParent() const { return BlockParent; }
203
204  Scope *getTemplateParamParent() { return TemplateParamParent; }
205  const Scope *getTemplateParamParent() const { return TemplateParamParent; }
206
207  /// Returns the number of function prototype scopes in this scope
208  /// chain.
209  unsigned getFunctionPrototypeDepth() const {
210    return PrototypeDepth;
211  }
212
213  /// Return the number of parameters declared in this function
214  /// prototype, increasing it by one for the next call.
215  unsigned getNextFunctionPrototypeIndex() {
216    assert(isFunctionPrototypeScope());
217    return PrototypeIndex++;
218  }
219
220  typedef DeclSetTy::iterator decl_iterator;
221  decl_iterator decl_begin() const { return DeclsInScope.begin(); }
222  decl_iterator decl_end()   const { return DeclsInScope.end(); }
223  bool decl_empty()          const { return DeclsInScope.empty(); }
224
225  void AddDecl(Decl *D) {
226    DeclsInScope.insert(D);
227  }
228
229  void RemoveDecl(Decl *D) {
230    DeclsInScope.erase(D);
231  }
232
233  /// isDeclScope - Return true if this is the scope that the specified decl is
234  /// declared in.
235  bool isDeclScope(Decl *D) {
236    return DeclsInScope.count(D) != 0;
237  }
238
239  void* getEntity() const { return Entity; }
240  void setEntity(void *E) { Entity = E; }
241
242  bool hasErrorOccurred() const { return ErrorTrap.hasErrorOccurred(); }
243
244  /// isClassScope - Return true if this scope is a class/struct/union scope.
245  bool isClassScope() const {
246    return (getFlags() & Scope::ClassScope);
247  }
248
249  /// isInCXXInlineMethodScope - Return true if this scope is a C++ inline
250  /// method scope or is inside one.
251  bool isInCXXInlineMethodScope() const {
252    if (const Scope *FnS = getFnParent()) {
253      assert(FnS->getParent() && "TUScope not created?");
254      return FnS->getParent()->isClassScope();
255    }
256    return false;
257  }
258
259  /// isInObjcMethodScope - Return true if this scope is, or is contained in, an
260  /// Objective-C method body.  Note that this method is not constant time.
261  bool isInObjcMethodScope() const {
262    for (const Scope *S = this; S; S = S->getParent()) {
263      // If this scope is an objc method scope, then we succeed.
264      if (S->getFlags() & ObjCMethodScope)
265        return true;
266    }
267    return false;
268  }
269
270  /// isTemplateParamScope - Return true if this scope is a C++
271  /// template parameter scope.
272  bool isTemplateParamScope() const {
273    return getFlags() & Scope::TemplateParamScope;
274  }
275
276  /// isFunctionPrototypeScope - Return true if this scope is a
277  /// function prototype scope.
278  bool isFunctionPrototypeScope() const {
279    return getFlags() & Scope::FunctionPrototypeScope;
280  }
281
282  /// isAtCatchScope - Return true if this scope is \@catch.
283  bool isAtCatchScope() const {
284    return getFlags() & Scope::AtCatchScope;
285  }
286
287  /// isSwitchScope - Return true if this scope is a switch scope.
288  bool isSwitchScope() const {
289    for (const Scope *S = this; S; S = S->getParent()) {
290      if (S->getFlags() & Scope::SwitchScope)
291        return true;
292      else if (S->getFlags() & (Scope::FnScope | Scope::ClassScope |
293                                Scope::BlockScope | Scope::TemplateParamScope |
294                                Scope::FunctionPrototypeScope |
295                                Scope::AtCatchScope | Scope::ObjCMethodScope))
296        return false;
297    }
298    return false;
299  }
300
301  /// \brief Determine whether this scope is a C++ 'try' block.
302  bool isTryScope() const { return getFlags() & Scope::TryScope; }
303
304  /// containedInPrototypeScope - Return true if this or a parent scope
305  /// is a FunctionPrototypeScope.
306  bool containedInPrototypeScope() const;
307
308  typedef UsingDirectivesTy::iterator udir_iterator;
309  typedef UsingDirectivesTy::const_iterator const_udir_iterator;
310
311  void PushUsingDirective(UsingDirectiveDecl *UDir) {
312    UsingDirectives.push_back(UDir);
313  }
314
315  udir_iterator using_directives_begin() {
316    return UsingDirectives.begin();
317  }
318
319  udir_iterator using_directives_end() {
320    return UsingDirectives.end();
321  }
322
323  const_udir_iterator using_directives_begin() const {
324    return UsingDirectives.begin();
325  }
326
327  const_udir_iterator using_directives_end() const {
328    return UsingDirectives.end();
329  }
330
331  /// Init - This is used by the parser to implement scope caching.
332  ///
333  void Init(Scope *parent, unsigned flags);
334};
335
336}  // end namespace clang
337
338#endif
339