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      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 
     21 namespace clang {
     22 
     23 class Decl;
     24 class 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 ///
     30 class Scope {
     31 public:
     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     /// FnScope - This indicates that the scope corresponds to a function, which
     36     /// means that labels are set here.
     37     FnScope       = 0x01,
     38 
     39     /// BreakScope - This is a while,do,switch,for, etc that can have break
     40     /// stmts embedded into it.
     41     BreakScope    = 0x02,
     42 
     43     /// ContinueScope - This is a while,do,for, which can have continue
     44     /// stmt embedded into it.
     45     ContinueScope = 0x04,
     46 
     47     /// DeclScope - 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     /// ControlScope - The controlling scope in a if/switch/while/for statement.
     52     ControlScope = 0x10,
     53 
     54     /// ClassScope - The scope of a struct/union/class definition.
     55     ClassScope = 0x20,
     56 
     57     /// BlockScope - 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, BreakScope, ContinueScope, and DeclScope flags set as well.
     61     BlockScope = 0x40,
     62 
     63     /// TemplateParamScope - 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     /// FunctionPrototypeScope - This is a scope that corresponds to the
     70     /// parameters within a function prototype.
     71     FunctionPrototypeScope = 0x100,
     72 
     73     /// AtCatchScope - This is a scope that corresponds to the Objective-C
     74     /// @catch statement.
     75     AtCatchScope = 0x200,
     76 
     77     /// ObjCMethodScope - This scope corresponds to an Objective-C method body.
     78     /// It always has FnScope and DeclScope set as well.
     79     ObjCMethodScope = 0x400,
     80 
     81     /// SwitchScope - This is a scope that corresponds to a switch statement.
     82     SwitchScope = 0x800,
     83 
     84     /// ThisScope - This is the scope of a struct/union/class definition,
     85     /// outside of any member function definition, where 'this' is nonetheless
     86     /// usable.
     87     ThisScope = 0x1000,
     88 
     89     /// TryScope - This is the scope of a C++ try statement.
     90     TryScope = 0x2000
     91   };
     92 private:
     93   /// The parent scope for this scope.  This is null for the translation-unit
     94   /// scope.
     95   Scope *AnyParent;
     96 
     97   /// Depth - This is the depth of this scope.  The translation-unit scope has
     98   /// depth 0.
     99   unsigned short Depth;
    100 
    101   /// Flags - This contains a set of ScopeFlags, which indicates how the scope
    102   /// interrelates with other control flow statements.
    103   unsigned short Flags;
    104 
    105   /// PrototypeDepth - This is the number of function prototype scopes
    106   /// enclosing this scope, including this scope.
    107   unsigned short PrototypeDepth;
    108 
    109   /// PrototypeIndex - This is the number of parameters currently
    110   /// declared in this scope.
    111   unsigned short PrototypeIndex;
    112 
    113   /// FnParent - If this scope has a parent scope that is a function body, this
    114   /// pointer is non-null and points to it.  This is used for label processing.
    115   Scope *FnParent;
    116 
    117   /// BreakParent/ContinueParent - This is a direct link to the immediately
    118   /// preceding BreakParent/ContinueParent if this scope is not one, or null if
    119   /// there is no containing break/continue scope.
    120   Scope *BreakParent, *ContinueParent;
    121 
    122   /// ControlParent - This is a direct link to the immediately
    123   /// preceding ControlParent if this scope is not one, or null if
    124   /// there is no containing control scope.
    125   Scope *ControlParent;
    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 
    158 public:
    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.  If the closest scope is a closure scope, we know
    184   /// that there is no loop *inside* the closure.
    185   Scope *getContinueParent() {
    186     if (ContinueParent && !ContinueParent->isBlockScope())
    187       return ContinueParent;
    188     return 0;
    189   }
    190 
    191   const Scope *getContinueParent() const {
    192     return const_cast<Scope*>(this)->getContinueParent();
    193   }
    194 
    195   /// getBreakParent - Return the closest scope that a break statement
    196   /// would be affected by.  If the closest scope is a block scope, we know
    197   /// that there is no loop *inside* the block.
    198   Scope *getBreakParent() {
    199     if (BreakParent && !BreakParent->isBlockScope())
    200       return BreakParent;
    201     return 0;
    202   }
    203   const Scope *getBreakParent() const {
    204     return const_cast<Scope*>(this)->getBreakParent();
    205   }
    206 
    207   Scope *getControlParent() { return ControlParent; }
    208   const Scope *getControlParent() const { return ControlParent; }
    209 
    210   Scope *getBlockParent() { return BlockParent; }
    211   const Scope *getBlockParent() const { return BlockParent; }
    212 
    213   Scope *getTemplateParamParent() { return TemplateParamParent; }
    214   const Scope *getTemplateParamParent() const { return TemplateParamParent; }
    215 
    216   /// Returns the number of function prototype scopes in this scope
    217   /// chain.
    218   unsigned getFunctionPrototypeDepth() const {
    219     return PrototypeDepth;
    220   }
    221 
    222   /// Return the number of parameters declared in this function
    223   /// prototype, increasing it by one for the next call.
    224   unsigned getNextFunctionPrototypeIndex() {
    225     assert(isFunctionPrototypeScope());
    226     return PrototypeIndex++;
    227   }
    228 
    229   typedef DeclSetTy::iterator decl_iterator;
    230   decl_iterator decl_begin() const { return DeclsInScope.begin(); }
    231   decl_iterator decl_end()   const { return DeclsInScope.end(); }
    232   bool decl_empty()          const { return DeclsInScope.empty(); }
    233 
    234   void AddDecl(Decl *D) {
    235     DeclsInScope.insert(D);
    236   }
    237 
    238   void RemoveDecl(Decl *D) {
    239     DeclsInScope.erase(D);
    240   }
    241 
    242   /// isDeclScope - Return true if this is the scope that the specified decl is
    243   /// declared in.
    244   bool isDeclScope(Decl *D) {
    245     return DeclsInScope.count(D) != 0;
    246   }
    247 
    248   void* getEntity() const { return Entity; }
    249   void setEntity(void *E) { Entity = E; }
    250 
    251   bool hasErrorOccurred() const { return ErrorTrap.hasErrorOccurred(); }
    252 
    253   /// isClassScope - Return true if this scope is a class/struct/union scope.
    254   bool isClassScope() const {
    255     return (getFlags() & Scope::ClassScope);
    256   }
    257 
    258   /// isInCXXInlineMethodScope - Return true if this scope is a C++ inline
    259   /// method scope or is inside one.
    260   bool isInCXXInlineMethodScope() const {
    261     if (const Scope *FnS = getFnParent()) {
    262       assert(FnS->getParent() && "TUScope not created?");
    263       return FnS->getParent()->isClassScope();
    264     }
    265     return false;
    266   }
    267 
    268   /// isInObjcMethodScope - Return true if this scope is, or is contained in, an
    269   /// Objective-C method body.  Note that this method is not constant time.
    270   bool isInObjcMethodScope() const {
    271     for (const Scope *S = this; S; S = S->getParent()) {
    272       // If this scope is an objc method scope, then we succeed.
    273       if (S->getFlags() & ObjCMethodScope)
    274         return true;
    275     }
    276     return false;
    277   }
    278 
    279   /// isTemplateParamScope - Return true if this scope is a C++
    280   /// template parameter scope.
    281   bool isTemplateParamScope() const {
    282     return getFlags() & Scope::TemplateParamScope;
    283   }
    284 
    285   /// isFunctionPrototypeScope - Return true if this scope is a
    286   /// function prototype scope.
    287   bool isFunctionPrototypeScope() const {
    288     return getFlags() & Scope::FunctionPrototypeScope;
    289   }
    290 
    291   /// isAtCatchScope - Return true if this scope is @catch.
    292   bool isAtCatchScope() const {
    293     return getFlags() & Scope::AtCatchScope;
    294   }
    295 
    296   /// isSwitchScope - Return true if this scope is a switch scope.
    297   bool isSwitchScope() const {
    298     for (const Scope *S = this; S; S = S->getParent()) {
    299       if (S->getFlags() & Scope::SwitchScope)
    300         return true;
    301       else if (S->getFlags() & (Scope::FnScope | Scope::ClassScope |
    302                                 Scope::BlockScope | Scope::TemplateParamScope |
    303                                 Scope::FunctionPrototypeScope |
    304                                 Scope::AtCatchScope | Scope::ObjCMethodScope))
    305         return false;
    306     }
    307     return false;
    308   }
    309 
    310   /// \brief Determine whether this scope is a C++ 'try' block.
    311   bool isTryScope() const { return getFlags() & Scope::TryScope; }
    312 
    313   typedef UsingDirectivesTy::iterator udir_iterator;
    314   typedef UsingDirectivesTy::const_iterator const_udir_iterator;
    315 
    316   void PushUsingDirective(UsingDirectiveDecl *UDir) {
    317     UsingDirectives.push_back(UDir);
    318   }
    319 
    320   udir_iterator using_directives_begin() {
    321     return UsingDirectives.begin();
    322   }
    323 
    324   udir_iterator using_directives_end() {
    325     return UsingDirectives.end();
    326   }
    327 
    328   const_udir_iterator using_directives_begin() const {
    329     return UsingDirectives.begin();
    330   }
    331 
    332   const_udir_iterator using_directives_end() const {
    333     return UsingDirectives.end();
    334   }
    335 
    336   /// Init - This is used by the parser to implement scope caching.
    337   ///
    338   void Init(Scope *parent, unsigned flags);
    339 };
    340 
    341 }  // end namespace clang
    342 
    343 #endif
    344