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clang::RecursiveASTVisitor< Derived > Class Template Reference

A class that does preordor or postorder depth-first traversal on the entire Clang AST and visits each node. More...

#include "clang/AST/RecursiveASTVisitor.h"

Inheritance diagram for clang::RecursiveASTVisitor< Derived >:
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Public Types

typedef SmallVectorImpl< llvm::PointerIntPair< Stmt *, 1, bool > > DataRecursionQueue
 A queue used for performing data recursion over statements. More...
 

Public Member Functions

Derived & getDerived ()
 Return a reference to the derived class. More...
 
bool shouldVisitTemplateInstantiations () const
 Return whether this visitor should recurse into template instantiations. More...
 
bool shouldWalkTypesOfTypeLocs () const
 Return whether this visitor should recurse into the types of TypeLocs. More...
 
bool shouldVisitImplicitCode () const
 Return whether this visitor should recurse into implicit code, e.g., implicit constructors and destructors. More...
 
bool shouldTraversePostOrder () const
 Return whether this visitor should traverse post-order. More...
 
bool TraverseStmt (Stmt *S, DataRecursionQueue *Queue=nullptr)
 Recursively visit a statement or expression, by dispatching to Traverse*() based on the argument's dynamic type. More...
 
bool dataTraverseStmtPre (Stmt *S)
 Invoked before visiting a statement or expression via data recursion. More...
 
bool dataTraverseStmtPost (Stmt *S)
 Invoked after visiting a statement or expression via data recursion. More...
 
bool TraverseType (QualType T)
 Recursively visit a type, by dispatching to Traverse*Type() based on the argument's getTypeClass() property. More...
 
bool TraverseTypeLoc (TypeLoc TL)
 Recursively visit a type with location, by dispatching to Traverse*TypeLoc() based on the argument type's getTypeClass() property. More...
 
bool TraverseAttr (Attr *At)
 Recursively visit an attribute, by dispatching to Traverse*Attr() based on the argument's dynamic type. More...
 
bool TraverseDecl (Decl *D)
 Recursively visit a declaration, by dispatching to Traverse*Decl() based on the argument's dynamic type. More...
 
bool TraverseNestedNameSpecifier (NestedNameSpecifier *NNS)
 Recursively visit a C++ nested-name-specifier. More...
 
bool TraverseNestedNameSpecifierLoc (NestedNameSpecifierLoc NNS)
 Recursively visit a C++ nested-name-specifier with location information. More...
 
bool TraverseDeclarationNameInfo (DeclarationNameInfo NameInfo)
 Recursively visit a name with its location information. More...
 
bool TraverseTemplateName (TemplateName Template)
 Recursively visit a template name and dispatch to the appropriate method. More...
 
bool TraverseTemplateArgument (const TemplateArgument &Arg)
 Recursively visit a template argument and dispatch to the appropriate method for the argument type. More...
 
bool TraverseTemplateArgumentLoc (const TemplateArgumentLoc &ArgLoc)
 Recursively visit a template argument location and dispatch to the appropriate method for the argument type. More...
 
bool TraverseTemplateArguments (const TemplateArgument *Args, unsigned NumArgs)
 Recursively visit a set of template arguments. More...
 
bool TraverseConstructorInitializer (CXXCtorInitializer *Init)
 Recursively visit a constructor initializer. More...
 
bool TraverseLambdaCapture (LambdaExpr *LE, const LambdaCapture *C, Expr *Init)
 Recursively visit a lambda capture. More...
 
bool TraverseLambdaBody (LambdaExpr *LE, DataRecursionQueue *Queue=nullptr)
 Recursively visit the body of a lambda expression. More...
 
bool TraverseSynOrSemInitListExpr (InitListExpr *S, DataRecursionQueue *Queue=nullptr)
 Recursively visit the syntactic or semantic form of an initialization list. More...
 
bool VisitAttr (Attr *A)
 
bool WalkUpFromStmt (Stmt *S)
 
bool VisitStmt (Stmt *S)
 
bool WalkUpFromType (Type *T)
 
bool VisitType (Type *T)
 
bool WalkUpFromTypeLoc (TypeLoc TL)
 
bool VisitTypeLoc (TypeLoc TL)
 
bool WalkUpFromQualifiedTypeLoc (QualifiedTypeLoc TL)
 
bool VisitQualifiedTypeLoc (QualifiedTypeLoc TL)
 
bool WalkUpFromUnqualTypeLoc (UnqualTypeLoc TL)
 
bool VisitUnqualTypeLoc (UnqualTypeLoc TL)
 
bool WalkUpFromDecl (Decl *D)
 
bool VisitDecl (Decl *D)
 

Detailed Description

template<typename Derived>
class clang::RecursiveASTVisitor< Derived >

A class that does preordor or postorder depth-first traversal on the entire Clang AST and visits each node.

This class performs three distinct tasks:

  1. traverse the AST (i.e. go to each node);
  2. at a given node, walk up the class hierarchy, starting from the node's dynamic type, until the top-most class (e.g. Stmt, Decl, or Type) is reached.
  3. given a (node, class) combination, where 'class' is some base class of the dynamic type of 'node', call a user-overridable function to actually visit the node.

These tasks are done by three groups of methods, respectively:

  1. TraverseDecl(Decl *x) does task #1. It is the entry point for traversing an AST rooted at x. This method simply dispatches (i.e. forwards) to TraverseFoo(Foo *x) where Foo is the dynamic type of *x, which calls WalkUpFromFoo(x) and then recursively visits the child nodes of x. TraverseStmt(Stmt *x) and TraverseType(QualType x) work similarly.
  2. WalkUpFromFoo(Foo *x) does task #2. It does not try to visit any child node of x. Instead, it first calls WalkUpFromBar(x) where Bar is the direct parent class of Foo (unless Foo has no parent), and then calls VisitFoo(x) (see the next list item).
  3. VisitFoo(Foo *x) does task #3.

These three method groups are tiered (Traverse* > WalkUpFrom* > Visit*). A method (e.g. Traverse*) may call methods from the same tier (e.g. other Traverse*) or one tier lower (e.g. WalkUpFrom*). It may not call methods from a higher tier.

Note that since WalkUpFromFoo() calls WalkUpFromBar() (where Bar is Foo's super class) before calling VisitFoo(), the result is that the Visit*() methods for a given node are called in the top-down order (e.g. for a node of type NamespaceDecl, the order will be VisitDecl(), VisitNamedDecl(), and then VisitNamespaceDecl()).

This scheme guarantees that all Visit*() calls for the same AST node are grouped together. In other words, Visit*() methods for different nodes are never interleaved.

Clients of this visitor should subclass the visitor (providing themselves as the template argument, using the curiously recurring template pattern) and override any of the Traverse*, WalkUpFrom*, and Visit* methods for declarations, types, statements, expressions, or other AST nodes where the visitor should customize behavior. Most users only need to override Visit*. Advanced users may override Traverse* and WalkUpFrom* to implement custom traversal strategies. Returning false from one of these overridden functions will abort the entire traversal.

By default, this visitor tries to visit every part of the explicit source code exactly once. The default policy towards templates is to descend into the 'pattern' class or function body, not any explicit or implicit instantiations. Explicit specializations are still visited, and the patterns of partial specializations are visited separately. This behavior can be changed by overriding shouldVisitTemplateInstantiations() in the derived class to return true, in which case all known implicit and explicit instantiations will be visited at the same time as the pattern from which they were produced.

By default, this visitor preorder traverses the AST. If postorder traversal is needed, the shouldTraversePostOrder method needs to be overriden to return true.

Definition at line 151 of file RecursiveASTVisitor.h.

Member Typedef Documentation

◆ DataRecursionQueue

template<typename Derived>
typedef SmallVectorImpl<llvm::PointerIntPair<Stmt *, 1, bool> > clang::RecursiveASTVisitor< Derived >::DataRecursionQueue

A queue used for performing data recursion over statements.

Parameters involving this type are used to implement data recursion over Stmts and Exprs within this class, and should typically not be explicitly specified by derived classes. The bool bit indicates whether the statement has been traversed or not.

Definition at line 159 of file RecursiveASTVisitor.h.

Member Function Documentation

◆ dataTraverseStmtPost()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::dataTraverseStmtPost ( Stmt S)
inline

Invoked after visiting a statement or expression via data recursion.

This is not invoked if the previously invoked dataTraverseStmtPre returned false.

Returns
false if the visitation was terminated early, true otherwise.

Definition at line 196 of file RecursiveASTVisitor.h.

◆ dataTraverseStmtPre()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::dataTraverseStmtPre ( Stmt S)
inline

Invoked before visiting a statement or expression via data recursion.

Returns
false to skip visiting the node, true otherwise.

Definition at line 189 of file RecursiveASTVisitor.h.

◆ getDerived()

template<typename Derived>
Derived& clang::RecursiveASTVisitor< Derived >::getDerived ( )
inline

◆ shouldTraversePostOrder()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::shouldTraversePostOrder ( ) const
inline

Return whether this visitor should traverse post-order.

Definition at line 177 of file RecursiveASTVisitor.h.

◆ shouldVisitImplicitCode()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::shouldVisitImplicitCode ( ) const
inline

Return whether this visitor should recurse into implicit code, e.g., implicit constructors and destructors.

Definition at line 174 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::TraverseDecl().

◆ shouldVisitTemplateInstantiations()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::shouldVisitTemplateInstantiations ( ) const
inline

Return whether this visitor should recurse into template instantiations.

Definition at line 166 of file RecursiveASTVisitor.h.

◆ shouldWalkTypesOfTypeLocs()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::shouldWalkTypesOfTypeLocs ( ) const
inline

Return whether this visitor should recurse into the types of TypeLocs.

Definition at line 170 of file RecursiveASTVisitor.h.

◆ TraverseAttr()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::TraverseAttr ( Attr At)

Recursively visit an attribute, by dispatching to Traverse*Attr() based on the argument's dynamic type.

Returns
false if the visitation was terminated early, true otherwise (including when the argument is a Null type location).

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost().

◆ TraverseConstructorInitializer()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseConstructorInitializer ( CXXCtorInitializer Init)

Recursively visit a constructor initializer.

This automatically dispatches to another visitor for the initializer expression, but not for the name of the initializer, so may be overridden for clients that need access to the name.

Returns
false if the visitation was terminated early, true otherwise.

Definition at line 886 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost().

◆ TraverseDecl()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseDecl ( Decl D)

Recursively visit a declaration, by dispatching to Traverse*Decl() based on the argument's dynamic type.

Returns
false if the visitation was terminated early, true otherwise (including when the argument is NULL).

Definition at line 686 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost(), clang::if(), and clang::RecursiveASTVisitor< CallGraph >::TraverseLambdaCapture().

◆ TraverseDeclarationNameInfo()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseDeclarationNameInfo ( DeclarationNameInfo  NameInfo)

Recursively visit a name with its location information.

Returns
false if the visitation was terminated early, true otherwise.

Definition at line 767 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost(), and clang::if().

◆ TraverseLambdaBody()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseLambdaBody ( LambdaExpr LE,
DataRecursionQueue Queue = nullptr 
)

Recursively visit the body of a lambda expression.

This provides a hook for visitors that need more context when visiting LE->getBody().

Returns
false if the visitation was terminated early, true otherwise.

Definition at line 910 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost().

◆ TraverseLambdaCapture()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseLambdaCapture ( LambdaExpr LE,
const LambdaCapture C,
Expr Init 
)

Recursively visit a lambda capture.

Init is the expression that will be used to initialize the capture.

Returns
false if the visitation was terminated early, true otherwise.

Definition at line 899 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost().

◆ TraverseNestedNameSpecifier()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseNestedNameSpecifier ( NestedNameSpecifier NNS)

Recursively visit a C++ nested-name-specifier.

Returns
false if the visitation was terminated early, true otherwise.

Definition at line 716 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost(), clang::RecursiveASTVisitor< CallGraph >::TraverseNestedNameSpecifier(), and clang::RecursiveASTVisitor< CallGraph >::TraverseTemplateName().

◆ TraverseNestedNameSpecifierLoc()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseNestedNameSpecifierLoc ( NestedNameSpecifierLoc  NNS)

Recursively visit a C++ nested-name-specifier with location information.

Returns
false if the visitation was terminated early, true otherwise.

Definition at line 741 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost(), clang::if(), and clang::RecursiveASTVisitor< CallGraph >::TraverseNestedNameSpecifierLoc().

◆ TraverseStmt()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseStmt ( Stmt S,
DataRecursionQueue Queue = nullptr 
)

Recursively visit a statement or expression, by dispatching to Traverse*() based on the argument's dynamic type.

Returns
false if the visitation was terminated early, true otherwise (including when the argument is nullptr).

Definition at line 605 of file RecursiveASTVisitor.h.

Referenced by clang::if(), clang::RecursiveASTVisitor< CallGraph >::shouldTraversePostOrder(), clang::RecursiveASTVisitor< CallGraph >::TraverseConstructorInitializer(), and clang::RecursiveASTVisitor< CallGraph >::TraverseLambdaCapture().

◆ TraverseSynOrSemInitListExpr()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::TraverseSynOrSemInitListExpr ( InitListExpr S,
DataRecursionQueue Queue = nullptr 
)

Recursively visit the syntactic or semantic form of an initialization list.

Returns
false if the visitation was terminated early, true otherwise.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost().

◆ TraverseTemplateArgument()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseTemplateArgument ( const TemplateArgument Arg)

Recursively visit a template argument and dispatch to the appropriate method for the argument type.

Returns
false if the visitation was terminated early, true otherwise.

Definition at line 806 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost().

◆ TraverseTemplateArgumentLoc()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseTemplateArgumentLoc ( const TemplateArgumentLoc ArgLoc)

Recursively visit a template argument location and dispatch to the appropriate method for the argument type.

Returns
false if the visitation was terminated early, true otherwise.

Definition at line 837 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost().

◆ TraverseTemplateArguments()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseTemplateArguments ( const TemplateArgument Args,
unsigned  NumArgs 
)

Recursively visit a set of template arguments.

This can be overridden by a subclass, but it's not expected that will be needed – this visitor always dispatches to another.

Returns
false if the visitation was terminated early, true otherwise.

Definition at line 876 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost().

◆ TraverseTemplateName()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseTemplateName ( TemplateName  Template)

Recursively visit a template name and dispatch to the appropriate method.

Returns
false if the visitation was terminated early, true otherwise.

Definition at line 796 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost(), and clang::RecursiveASTVisitor< CallGraph >::TraverseDeclarationNameInfo().

◆ TraverseType()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseType ( QualType  T)

Recursively visit a type, by dispatching to Traverse*Type() based on the argument's getTypeClass() property.

Returns
false if the visitation was terminated early, true otherwise (including when the argument is a Null type).

Definition at line 649 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost(), clang::if(), and clang::RecursiveASTVisitor< CallGraph >::TraverseNestedNameSpecifier().

◆ TraverseTypeLoc()

template<typename Derived >
bool clang::RecursiveASTVisitor< Derived >::TraverseTypeLoc ( TypeLoc  TL)

Recursively visit a type with location, by dispatching to Traverse*TypeLoc() based on the argument type's getTypeClass() property.

Returns
false if the visitation was terminated early, true otherwise (including when the argument is a Null type location).

Definition at line 665 of file RecursiveASTVisitor.h.

Referenced by clang::RecursiveASTVisitor< CallGraph >::dataTraverseStmtPost(), clang::if(), clang::RecursiveASTVisitor< CallGraph >::TraverseConstructorInitializer(), clang::RecursiveASTVisitor< CallGraph >::TraverseDeclarationNameInfo(), and clang::RecursiveASTVisitor< CallGraph >::TraverseNestedNameSpecifierLoc().

◆ VisitAttr()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::VisitAttr ( Attr A)
inline

Definition at line 303 of file RecursiveASTVisitor.h.

◆ VisitDecl()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::VisitDecl ( Decl D)
inline

Definition at line 484 of file RecursiveASTVisitor.h.

◆ VisitQualifiedTypeLoc()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::VisitQualifiedTypeLoc ( QualifiedTypeLoc  TL)
inline

Definition at line 458 of file RecursiveASTVisitor.h.

◆ VisitStmt()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::VisitStmt ( Stmt S)
inline

Definition at line 355 of file RecursiveASTVisitor.h.

◆ VisitType()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::VisitType ( Type T)
inline

Definition at line 430 of file RecursiveASTVisitor.h.

◆ VisitTypeLoc()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::VisitTypeLoc ( TypeLoc  TL)
inline

Definition at line 451 of file RecursiveASTVisitor.h.

◆ VisitUnqualTypeLoc()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::VisitUnqualTypeLoc ( UnqualTypeLoc  TL)
inline

Definition at line 462 of file RecursiveASTVisitor.h.

◆ WalkUpFromDecl()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::WalkUpFromDecl ( Decl D)
inline

Definition at line 483 of file RecursiveASTVisitor.h.

◆ WalkUpFromQualifiedTypeLoc()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::WalkUpFromQualifiedTypeLoc ( QualifiedTypeLoc  TL)
inline

Definition at line 455 of file RecursiveASTVisitor.h.

◆ WalkUpFromStmt()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::WalkUpFromStmt ( Stmt S)
inline

Definition at line 354 of file RecursiveASTVisitor.h.

◆ WalkUpFromType()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::WalkUpFromType ( Type T)
inline

Definition at line 429 of file RecursiveASTVisitor.h.

◆ WalkUpFromTypeLoc()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::WalkUpFromTypeLoc ( TypeLoc  TL)
inline

Definition at line 450 of file RecursiveASTVisitor.h.

◆ WalkUpFromUnqualTypeLoc()

template<typename Derived>
bool clang::RecursiveASTVisitor< Derived >::WalkUpFromUnqualTypeLoc ( UnqualTypeLoc  TL)
inline

Definition at line 459 of file RecursiveASTVisitor.h.


The documentation for this class was generated from the following file: