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/PointerIntPair.h"
19#include "llvm/ADT/SmallPtrSet.h"
20#include "llvm/ADT/SmallVector.h"
21
22namespace llvm {
23
24class raw_ostream;
25
26}
27
28namespace clang {
29
30class Decl;
31class UsingDirectiveDecl;
32class VarDecl;
33
34/// Scope - A scope is a transient data structure that is used while parsing the
35/// program.  It assists with resolving identifiers to the appropriate
36/// declaration.
37///
38class Scope {
39public:
40  /// ScopeFlags - These are bitfields that are or'd together when creating a
41  /// scope, which defines the sorts of things the scope contains.
42  enum ScopeFlags {
43    /// \brief This indicates that the scope corresponds to a function, which
44    /// means that labels are set here.
45    FnScope       = 0x01,
46
47    /// \brief This is a while, do, switch, for, etc that can have break
48    /// statements embedded into it.
49    BreakScope    = 0x02,
50
51    /// \brief This is a while, do, for, which can have continue statements
52    /// embedded into it.
53    ContinueScope = 0x04,
54
55    /// \brief This is a scope that can contain a declaration.  Some scopes
56    /// just contain loop constructs but don't contain decls.
57    DeclScope = 0x08,
58
59    /// \brief The controlling scope in a if/switch/while/for statement.
60    ControlScope = 0x10,
61
62    /// \brief The scope of a struct/union/class definition.
63    ClassScope = 0x20,
64
65    /// \brief This is a scope that corresponds to a block/closure object.
66    /// Blocks serve as top-level scopes for some objects like labels, they
67    /// also prevent things like break and continue.  BlockScopes always have
68    /// the FnScope and DeclScope flags set as well.
69    BlockScope = 0x40,
70
71    /// \brief This is a scope that corresponds to the
72    /// template parameters of a C++ template. Template parameter
73    /// scope starts at the 'template' keyword and ends when the
74    /// template declaration ends.
75    TemplateParamScope = 0x80,
76
77    /// \brief This is a scope that corresponds to the
78    /// parameters within a function prototype.
79    FunctionPrototypeScope = 0x100,
80
81    /// \brief This is a scope that corresponds to the parameters within
82    /// a function prototype for a function declaration (as opposed to any
83    /// other kind of function declarator). Always has FunctionPrototypeScope
84    /// set as well.
85    FunctionDeclarationScope = 0x200,
86
87    /// \brief This is a scope that corresponds to the Objective-C
88    /// \@catch statement.
89    AtCatchScope = 0x400,
90
91    /// \brief This scope corresponds to an Objective-C method body.
92    /// It always has FnScope and DeclScope set as well.
93    ObjCMethodScope = 0x800,
94
95    /// \brief This is a scope that corresponds to a switch statement.
96    SwitchScope = 0x1000,
97
98    /// \brief This is the scope of a C++ try statement.
99    TryScope = 0x2000,
100
101    /// \brief This is the scope for a function-level C++ try or catch scope.
102    FnTryCatchScope = 0x4000,
103
104    /// \brief This is the scope of OpenMP executable directive.
105    OpenMPDirectiveScope = 0x8000,
106
107    /// \brief This is the scope of some OpenMP loop directive.
108    OpenMPLoopDirectiveScope = 0x10000,
109
110    /// \brief This is the scope of some OpenMP simd directive.
111    /// For example, it is used for 'omp simd', 'omp for simd'.
112    /// This flag is propagated to children scopes.
113    OpenMPSimdDirectiveScope = 0x20000,
114
115    /// This scope corresponds to an enum.
116    EnumScope = 0x40000,
117
118    /// This scope corresponds to a SEH try.
119    SEHTryScope = 0x80000,
120  };
121private:
122  /// The parent scope for this scope.  This is null for the translation-unit
123  /// scope.
124  Scope *AnyParent;
125
126  /// Flags - This contains a set of ScopeFlags, which indicates how the scope
127  /// interrelates with other control flow statements.
128  unsigned Flags;
129
130  /// Depth - This is the depth of this scope.  The translation-unit scope has
131  /// depth 0.
132  unsigned short Depth;
133
134  /// \brief Declarations with static linkage are mangled with the number of
135  /// scopes seen as a component.
136  unsigned short MSLocalManglingNumber;
137
138  /// PrototypeDepth - This is the number of function prototype scopes
139  /// enclosing this scope, including this scope.
140  unsigned short PrototypeDepth;
141
142  /// PrototypeIndex - This is the number of parameters currently
143  /// declared in this scope.
144  unsigned short PrototypeIndex;
145
146  /// FnParent - If this scope has a parent scope that is a function body, this
147  /// pointer is non-null and points to it.  This is used for label processing.
148  Scope *FnParent;
149  Scope *MSLocalManglingParent;
150
151  /// BreakParent/ContinueParent - This is a direct link to the innermost
152  /// BreakScope/ContinueScope which contains the contents of this scope
153  /// for control flow purposes (and might be this scope itself), or null
154  /// if there is no such scope.
155  Scope *BreakParent, *ContinueParent;
156
157  /// BlockParent - This is a direct link to the immediately containing
158  /// BlockScope if this scope is not one, or null if there is none.
159  Scope *BlockParent;
160
161  /// TemplateParamParent - This is a direct link to the
162  /// immediately containing template parameter scope. In the
163  /// case of nested templates, template parameter scopes can have
164  /// other template parameter scopes as parents.
165  Scope *TemplateParamParent;
166
167  /// DeclsInScope - This keeps track of all declarations in this scope.  When
168  /// the declaration is added to the scope, it is set as the current
169  /// declaration for the identifier in the IdentifierTable.  When the scope is
170  /// popped, these declarations are removed from the IdentifierTable's notion
171  /// of current declaration.  It is up to the current Action implementation to
172  /// implement these semantics.
173  typedef llvm::SmallPtrSet<Decl *, 32> DeclSetTy;
174  DeclSetTy DeclsInScope;
175
176  /// The DeclContext with which this scope is associated. For
177  /// example, the entity of a class scope is the class itself, the
178  /// entity of a function scope is a function, etc.
179  DeclContext *Entity;
180
181  typedef SmallVector<UsingDirectiveDecl *, 2> UsingDirectivesTy;
182  UsingDirectivesTy UsingDirectives;
183
184  /// \brief Used to determine if errors occurred in this scope.
185  DiagnosticErrorTrap ErrorTrap;
186
187  /// A lattice consisting of undefined, a single NRVO candidate variable in
188  /// this scope, or over-defined. The bit is true when over-defined.
189  llvm::PointerIntPair<VarDecl *, 1, bool> NRVO;
190
191public:
192  Scope(Scope *Parent, unsigned ScopeFlags, DiagnosticsEngine &Diag)
193    : ErrorTrap(Diag) {
194    Init(Parent, ScopeFlags);
195  }
196
197  /// getFlags - Return the flags for this scope.
198  ///
199  unsigned getFlags() const { return Flags; }
200  void setFlags(unsigned F) { Flags = F; }
201
202  /// isBlockScope - Return true if this scope correspond to a closure.
203  bool isBlockScope() const { return Flags & BlockScope; }
204
205  /// getParent - Return the scope that this is nested in.
206  ///
207  const Scope *getParent() const { return AnyParent; }
208  Scope *getParent() { return AnyParent; }
209
210  /// getFnParent - Return the closest scope that is a function body.
211  ///
212  const Scope *getFnParent() const { return FnParent; }
213  Scope *getFnParent() { return FnParent; }
214
215  const Scope *getMSLocalManglingParent() const {
216    return MSLocalManglingParent;
217  }
218  Scope *getMSLocalManglingParent() { return MSLocalManglingParent; }
219
220  /// getContinueParent - Return the closest scope that a continue statement
221  /// would be affected by.
222  Scope *getContinueParent() {
223    return ContinueParent;
224  }
225
226  const Scope *getContinueParent() const {
227    return const_cast<Scope*>(this)->getContinueParent();
228  }
229
230  /// getBreakParent - Return the closest scope that a break statement
231  /// would be affected by.
232  Scope *getBreakParent() {
233    return BreakParent;
234  }
235  const Scope *getBreakParent() const {
236    return const_cast<Scope*>(this)->getBreakParent();
237  }
238
239  Scope *getBlockParent() { return BlockParent; }
240  const Scope *getBlockParent() const { return BlockParent; }
241
242  Scope *getTemplateParamParent() { return TemplateParamParent; }
243  const Scope *getTemplateParamParent() const { return TemplateParamParent; }
244
245  /// Returns the number of function prototype scopes in this scope
246  /// chain.
247  unsigned getFunctionPrototypeDepth() const {
248    return PrototypeDepth;
249  }
250
251  /// Return the number of parameters declared in this function
252  /// prototype, increasing it by one for the next call.
253  unsigned getNextFunctionPrototypeIndex() {
254    assert(isFunctionPrototypeScope());
255    return PrototypeIndex++;
256  }
257
258  typedef llvm::iterator_range<DeclSetTy::iterator> decl_range;
259  decl_range decls() const {
260    return decl_range(DeclsInScope.begin(), DeclsInScope.end());
261  }
262  bool decl_empty() const { return DeclsInScope.empty(); }
263
264  void AddDecl(Decl *D) {
265    DeclsInScope.insert(D);
266  }
267
268  void RemoveDecl(Decl *D) {
269    DeclsInScope.erase(D);
270  }
271
272  void incrementMSLocalManglingNumber() {
273    if (Scope *MSLMP = getMSLocalManglingParent())
274      MSLMP->MSLocalManglingNumber += 1;
275  }
276
277  void decrementMSLocalManglingNumber() {
278    if (Scope *MSLMP = getMSLocalManglingParent())
279      MSLMP->MSLocalManglingNumber -= 1;
280  }
281
282  unsigned getMSLocalManglingNumber() const {
283    if (const Scope *MSLMP = getMSLocalManglingParent())
284      return MSLMP->MSLocalManglingNumber;
285    return 1;
286  }
287
288  /// isDeclScope - Return true if this is the scope that the specified decl is
289  /// declared in.
290  bool isDeclScope(Decl *D) {
291    return DeclsInScope.count(D) != 0;
292  }
293
294  DeclContext *getEntity() const { return Entity; }
295  void setEntity(DeclContext *E) { Entity = E; }
296
297  bool hasErrorOccurred() const { return ErrorTrap.hasErrorOccurred(); }
298
299  bool hasUnrecoverableErrorOccurred() const {
300    return ErrorTrap.hasUnrecoverableErrorOccurred();
301  }
302
303  /// isClassScope - Return true if this scope is a class/struct/union scope.
304  bool isClassScope() const {
305    return (getFlags() & Scope::ClassScope);
306  }
307
308  /// isInCXXInlineMethodScope - Return true if this scope is a C++ inline
309  /// method scope or is inside one.
310  bool isInCXXInlineMethodScope() const {
311    if (const Scope *FnS = getFnParent()) {
312      assert(FnS->getParent() && "TUScope not created?");
313      return FnS->getParent()->isClassScope();
314    }
315    return false;
316  }
317
318  /// isInObjcMethodScope - Return true if this scope is, or is contained in, an
319  /// Objective-C method body.  Note that this method is not constant time.
320  bool isInObjcMethodScope() const {
321    for (const Scope *S = this; S; S = S->getParent()) {
322      // If this scope is an objc method scope, then we succeed.
323      if (S->getFlags() & ObjCMethodScope)
324        return true;
325    }
326    return false;
327  }
328
329  /// isInObjcMethodOuterScope - Return true if this scope is an
330  /// Objective-C method outer most body.
331  bool isInObjcMethodOuterScope() const {
332    if (const Scope *S = this) {
333      // If this scope is an objc method scope, then we succeed.
334      if (S->getFlags() & ObjCMethodScope)
335        return true;
336    }
337    return false;
338  }
339
340
341  /// isTemplateParamScope - Return true if this scope is a C++
342  /// template parameter scope.
343  bool isTemplateParamScope() const {
344    return getFlags() & Scope::TemplateParamScope;
345  }
346
347  /// isFunctionPrototypeScope - Return true if this scope is a
348  /// function prototype scope.
349  bool isFunctionPrototypeScope() const {
350    return getFlags() & Scope::FunctionPrototypeScope;
351  }
352
353  /// isAtCatchScope - Return true if this scope is \@catch.
354  bool isAtCatchScope() const {
355    return getFlags() & Scope::AtCatchScope;
356  }
357
358  /// isSwitchScope - Return true if this scope is a switch scope.
359  bool isSwitchScope() const {
360    for (const Scope *S = this; S; S = S->getParent()) {
361      if (S->getFlags() & Scope::SwitchScope)
362        return true;
363      else if (S->getFlags() & (Scope::FnScope | Scope::ClassScope |
364                                Scope::BlockScope | Scope::TemplateParamScope |
365                                Scope::FunctionPrototypeScope |
366                                Scope::AtCatchScope | Scope::ObjCMethodScope))
367        return false;
368    }
369    return false;
370  }
371
372  /// \brief Determines whether this scope is the OpenMP directive scope
373  bool isOpenMPDirectiveScope() const {
374    return (getFlags() & Scope::OpenMPDirectiveScope);
375  }
376
377  /// \brief Determine whether this scope is some OpenMP loop directive scope
378  /// (for example, 'omp for', 'omp simd').
379  bool isOpenMPLoopDirectiveScope() const {
380    if (getFlags() & Scope::OpenMPLoopDirectiveScope) {
381      assert(isOpenMPDirectiveScope() &&
382             "OpenMP loop directive scope is not a directive scope");
383      return true;
384    }
385    return false;
386  }
387
388  /// \brief Determine whether this scope is (or is nested into) some OpenMP
389  /// loop simd directive scope (for example, 'omp simd', 'omp for simd').
390  bool isOpenMPSimdDirectiveScope() const {
391    return getFlags() & Scope::OpenMPSimdDirectiveScope;
392  }
393
394  /// \brief Determine whether this scope is a loop having OpenMP loop
395  /// directive attached.
396  bool isOpenMPLoopScope() const {
397    const Scope *P = getParent();
398    return P && P->isOpenMPLoopDirectiveScope();
399  }
400
401  /// \brief Determine whether this scope is a C++ 'try' block.
402  bool isTryScope() const { return getFlags() & Scope::TryScope; }
403
404  /// \brief Determine whether this scope is a SEH '__try' block.
405  bool isSEHTryScope() const { return getFlags() & Scope::SEHTryScope; }
406
407  /// containedInPrototypeScope - Return true if this or a parent scope
408  /// is a FunctionPrototypeScope.
409  bool containedInPrototypeScope() const;
410
411  void PushUsingDirective(UsingDirectiveDecl *UDir) {
412    UsingDirectives.push_back(UDir);
413  }
414
415  typedef llvm::iterator_range<UsingDirectivesTy::iterator>
416    using_directives_range;
417
418  using_directives_range using_directives() {
419    return using_directives_range(UsingDirectives.begin(),
420                                  UsingDirectives.end());
421  }
422
423  void addNRVOCandidate(VarDecl *VD) {
424    if (NRVO.getInt())
425      return;
426    if (NRVO.getPointer() == nullptr) {
427      NRVO.setPointer(VD);
428      return;
429    }
430    if (NRVO.getPointer() != VD)
431      setNoNRVO();
432  }
433
434  void setNoNRVO() {
435    NRVO.setInt(1);
436    NRVO.setPointer(nullptr);
437  }
438
439  void mergeNRVOIntoParent();
440
441  /// Init - This is used by the parser to implement scope caching.
442  ///
443  void Init(Scope *parent, unsigned flags);
444
445  /// \brief Sets up the specified scope flags and adjusts the scope state
446  /// variables accordingly.
447  ///
448  void AddFlags(unsigned Flags);
449
450  void dumpImpl(raw_ostream &OS) const;
451  void dump() const;
452};
453
454}  // end namespace clang
455
456#endif
457