Move TraversalKind enum to ast_type_traits

[steveire]

Summary

Make it usable outside of ASTMatchFinder. This will make it possible to
use this enum to control whether certain implicit nodes are skipped
while AST dumping for example.

[steveire]

This is part of the work I demo'd at EuroLLVM for ignoring invisible AST nodes during AST Matching and dumping: http://ce.steveire.com/z/lHYwEH

[steveire]

Format

[aaron.ballman]

LGTM aside from some commenting requests.

include/clang/AST/ASTTypeTraits.h

44

s/any/all ?

47

Can you update the comment to more clearly state what is skipped, because it's more than just implicit casts and parentheses?

If we can find a better name for the traversal kind, then great, but I can't think of one. IgnoreRandomImplicitJunk doesn't seem like an improvement, despite it being more accurate. :-P

[steveire]

Thanks, I made the comment changes in a separate commit because otherwise this would cease to be a refactoring commit. Commits get too noisy if their content is modified "mid-flight".

include/clang/AST/ASTTypeTraits.h

 }
 
 namespace clang {
 
 struct PrintingPolicy;
 
 namespace ast_type_traits {
 
+/// Defines how we descend a level in the AST when we pass
+/// through expressions.
+enum TraversalKind {
+  /// Will traverse any child nodes.
+  TK_AsIs,
+
+  /// Will not traverse implicit casts and parentheses.
+  TK_IgnoreImplicitCastsAndParentheses
+};
+
 /// Kind identifier.
 ///
 /// It can be constructed from any node kind and allows for runtime type
 /// hierarchy checks.
 /// Use getFromNodeKind<T>() to construct them.
 class ASTNodeKind {
 public:
   /// Empty identifier. It matches nothing.

include/clang/ASTMatchers/ASTMatchersInternal.h

 ///   at least one ancestor matched.
 ///
 /// FIXME: Currently we only allow Stmt and Decl nodes to start a traversal.
 /// In the future, we want to implement this for all nodes for which it makes
 /// sense. In the case of matchesAncestorOf, we'll want to implement it for
 /// all nodes, as all nodes have ancestors.
 class ASTMatchFinder {
 public:
-  /// Defines how we descend a level in the AST when we pass
-  /// through expressions.
-  enum TraversalKind {
-    /// Will traverse any child nodes.
-    TK_AsIs,
-
-    /// Will not traverse implicit casts and parentheses.
-    TK_IgnoreImplicitCastsAndParentheses
-  };
 
   /// Defines how bindings are processed on recursive matches.
   enum BindKind {
     /// Stop at the first match and only bind the first match.
     BK_First,
 
     /// Create results for all combinations of bindings that match.
     BK_All
public:
   /// from a base type matching \c base.
   ///
   /// A class is considered to be also derived from itself.
   virtual bool classIsDerivedFrom(const CXXRecordDecl *Declaration,
                                   const Matcher<NamedDecl> &Base,
                                   BoundNodesTreeBuilder *Builder) = 0;
 
   template <typename T>
-  bool matchesChildOf(const T &Node,
-                      const DynTypedMatcher &Matcher,
+  bool matchesChildOf(const T &Node, const DynTypedMatcher &Matcher,
                       BoundNodesTreeBuilder *Builder,
-                      TraversalKind Traverse,
-                      BindKind Bind) {
+                      ast_type_traits::TraversalKind Traverse, BindKind Bind) {
     static_assert(std::is_base_of<Decl, T>::value ||
                   std::is_base_of<Stmt, T>::value ||
                   std::is_base_of<NestedNameSpecifier, T>::value ||
                   std::is_base_of<NestedNameSpecifierLoc, T>::value ||
                   std::is_base_of<TypeLoc, T>::value ||
                   std::is_base_of<QualType, T>::value,
                   "unsupported type for recursive matching");
     return matchesChildOf(ast_type_traits::DynTypedNode::create(Node),
public:
   }
 
   virtual ASTContext &getASTContext() const = 0;
 
 protected:
   virtual bool matchesChildOf(const ast_type_traits::DynTypedNode &Node,
                               const DynTypedMatcher &Matcher,
                               BoundNodesTreeBuilder *Builder,
-                              TraversalKind Traverse,
+                              ast_type_traits::TraversalKind Traverse,
                               BindKind Bind) = 0;
 
   virtual bool matchesDescendantOf(const ast_type_traits::DynTypedNode &Node,
                                    const DynTypedMatcher &Matcher,
                                    BoundNodesTreeBuilder *Builder,
                                    BindKind Bind) = 0;
 
   virtual bool matchesAncestorOf(const ast_type_traits::DynTypedNode &Node,

 class HasMatcher : public WrapperMatcherInterface<T> {
 public:
   explicit HasMatcher(const Matcher<ChildT> &ChildMatcher)
       : HasMatcher::WrapperMatcherInterface(ChildMatcher) {}
 
   bool matches(const T &Node, ASTMatchFinder *Finder,
                BoundNodesTreeBuilder *Builder) const override {
     return Finder->matchesChildOf(Node, this->InnerMatcher, Builder,
-                                  ASTMatchFinder::TK_AsIs,
+                                  ast_type_traits::TraversalKind::TK_AsIs,
                                   ASTMatchFinder::BK_First);
   }
 };
 
 /// Matches nodes of type T that have child nodes of type ChildT for
 /// which a specified child matcher matches. ChildT must be an AST base
 /// type.
 /// As opposed to the HasMatcher, the ForEachMatcher will produce a match
 /// for each child that matches.
 template <typename T, typename ChildT>
 class ForEachMatcher : public WrapperMatcherInterface<T> {
   static_assert(IsBaseType<ChildT>::value,
                 "for each only accepts base type matcher");
 
  public:
    explicit ForEachMatcher(const Matcher<ChildT> &ChildMatcher)
        : ForEachMatcher::WrapperMatcherInterface(ChildMatcher) {}
 
   bool matches(const T& Node, ASTMatchFinder* Finder,
                BoundNodesTreeBuilder* Builder) const override {
     return Finder->matchesChildOf(
         Node, this->InnerMatcher, Builder,
-        ASTMatchFinder::TK_IgnoreImplicitCastsAndParentheses,
+        ast_type_traits::TraversalKind::TK_IgnoreImplicitCastsAndParentheses,
         ASTMatchFinder::BK_All);
   }
 };
 
 /// VariadicOperatorMatcher related types.
 /// @{
 
 /// Polymorphic matcher object that uses a \c

lib/ASTMatchers/ASTMatchFinder.cpp

class MatchChildASTVisitor
     : public RecursiveASTVisitor<MatchChildASTVisitor> {
 public:
   typedef RecursiveASTVisitor<MatchChildASTVisitor> VisitorBase;
 
   // Creates an AST visitor that matches 'matcher' on all children or
   // descendants of a traversed node. max_depth is the maximum depth
   // to traverse: use 1 for matching the children and INT_MAX for
   // matching the descendants.
-  MatchChildASTVisitor(const DynTypedMatcher *Matcher,
-                       ASTMatchFinder *Finder,
-                       BoundNodesTreeBuilder *Builder,
-                       int MaxDepth,
-                       ASTMatchFinder::TraversalKind Traversal,
+  MatchChildASTVisitor(const DynTypedMatcher *Matcher, ASTMatchFinder *Finder,
+                       BoundNodesTreeBuilder *Builder, int MaxDepth,
+                       ast_type_traits::TraversalKind Traversal,
                        ASTMatchFinder::BindKind Bind)
-      : Matcher(Matcher),
-        Finder(Finder),
-        Builder(Builder),
-        CurrentDepth(0),
-        MaxDepth(MaxDepth),
-        Traversal(Traversal),
-        Bind(Bind),
-        Matches(false) {}
+      : Matcher(Matcher), Finder(Finder), Builder(Builder), CurrentDepth(0),
+        MaxDepth(MaxDepth), Traversal(Traversal), Bind(Bind), Matches(false) {}
 
   // Returns true if a match is found in the subtree rooted at the
   // given AST node. This is done via a set of mutually recursive
   // functions. Here's how the recursion is done (the  *wildcard can
   // actually be Decl, Stmt, or Type):
   //
   //   - Traverse(node) calls BaseTraverse(node) when it needs
   //     to visit the descendants of node.
public:
   }
   bool TraverseStmt(Stmt *StmtNode, DataRecursionQueue *Queue = nullptr) {
     // If we need to keep track of the depth, we can't perform data recursion.
     if (CurrentDepth == 0 || (CurrentDepth <= MaxDepth && MaxDepth < INT_MAX))
       Queue = nullptr;
 
     ScopedIncrement ScopedDepth(&CurrentDepth);
     Stmt *StmtToTraverse = StmtNode;
-    if (Traversal == ASTMatchFinder::TK_IgnoreImplicitCastsAndParentheses) {
+    if (Traversal ==
+        ast_type_traits::TraversalKind::TK_IgnoreImplicitCastsAndParentheses) {
       if (Expr *ExprNode = dyn_cast_or_null<Expr>(StmtNode))
         StmtToTraverse = ExprNode->IgnoreParenImpCasts();
     }
     if (!StmtToTraverse)
       return true;
     if (!match(*StmtToTraverse))
       return false;
     return VisitorBase::TraverseStmt(StmtToTraverse, Queue);
private:
   }
 
   const DynTypedMatcher *const Matcher;
   ASTMatchFinder *const Finder;
   BoundNodesTreeBuilder *const Builder;
   BoundNodesTreeBuilder ResultBindings;
   int CurrentDepth;
   const int MaxDepth;
-  const ASTMatchFinder::TraversalKind Traversal;
+  const ast_type_traits::TraversalKind Traversal;
   const ASTMatchFinder::BindKind Bind;
   bool Matches;
 };
 
 // Controls the outermost traversal of the AST and allows to match multiple
 // matchers.
 class MatchASTVisitor : public RecursiveASTVisitor<MatchASTVisitor>,
                         public ASTMatchFinder {
public:
   bool TraverseNestedNameSpecifier(NestedNameSpecifier *NNS);
   bool TraverseNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS);
   bool TraverseConstructorInitializer(CXXCtorInitializer *CtorInit);
 
   // Matches children or descendants of 'Node' with 'BaseMatcher'.
   bool memoizedMatchesRecursively(const ast_type_traits::DynTypedNode &Node,
                                   const DynTypedMatcher &Matcher,
                                   BoundNodesTreeBuilder *Builder, int MaxDepth,
-                                  TraversalKind Traversal, BindKind Bind) {
+                                  ast_type_traits::TraversalKind Traversal,
+                                  BindKind Bind) {
     // For AST-nodes that don't have an identity, we can't memoize.
     if (!Node.getMemoizationData() || !Builder->isComparable())
       return matchesRecursively(Node, Matcher, Builder, MaxDepth, Traversal,
                                 Bind);
 
     MatchKey Key;
     Key.MatcherID = Matcher.getID();
     Key.Node = Node;
bool memoizedMatchesRecursively(const ast_type_traits::DynTypedNode &Node,
     *Builder = CachedResult.Nodes;
     return CachedResult.ResultOfMatch;
   }
 
   // Matches children or descendants of 'Node' with 'BaseMatcher'.
   bool matchesRecursively(const ast_type_traits::DynTypedNode &Node,
                           const DynTypedMatcher &Matcher,
                           BoundNodesTreeBuilder *Builder, int MaxDepth,
-                          TraversalKind Traversal, BindKind Bind) {
+                          ast_type_traits::TraversalKind Traversal,
+                          BindKind Bind) {
     MatchChildASTVisitor Visitor(
       &Matcher, this, Builder, MaxDepth, Traversal, Bind);
     return Visitor.findMatch(Node);
   }
 
   bool classIsDerivedFrom(const CXXRecordDecl *Declaration,
                           const Matcher<NamedDecl> &Base,
                           BoundNodesTreeBuilder *Builder) override;
 
   // Implements ASTMatchFinder::matchesChildOf.
   bool matchesChildOf(const ast_type_traits::DynTypedNode &Node,
                       const DynTypedMatcher &Matcher,
                       BoundNodesTreeBuilder *Builder,
-                      TraversalKind Traversal,
+                      ast_type_traits::TraversalKind Traversal,
                       BindKind Bind) override {
     if (ResultCache.size() > MaxMemoizationEntries)
       ResultCache.clear();
     return memoizedMatchesRecursively(Node, Matcher, Builder, 1, Traversal,
                                       Bind);
   }
   // Implements ASTMatchFinder::matchesDescendantOf.
   bool matchesDescendantOf(const ast_type_traits::DynTypedNode &Node,
                            const DynTypedMatcher &Matcher,
                            BoundNodesTreeBuilder *Builder,
                            BindKind Bind) override {
     if (ResultCache.size() > MaxMemoizationEntries)
       ResultCache.clear();
     return memoizedMatchesRecursively(Node, Matcher, Builder, INT_MAX,
-                                      TK_AsIs, Bind);
+                                      ast_type_traits::TraversalKind::TK_AsIs,
+                                      Bind);
   }
   // Implements ASTMatchFinder::matchesAncestorOf.
   bool matchesAncestorOf(const ast_type_traits::DynTypedNode &Node,
                          const DynTypedMatcher &Matcher,
                          BoundNodesTreeBuilder *Builder,
                          AncestorMatchMode MatchMode) override {
     // Reset the cache outside of the recursive call to make sure we
     // don't invalidate any iterators.

unittests/ASTMatchers/ASTMatchersInternalTest.cpp

EXPECT_TRUE(matchAndVerifyResultFalse("class A { class C {}; };",
       HasClassB, llvm::make_unique<VerifyIdIsBoundTo<Decl>>("b")));
 }
 
 AST_POLYMORPHIC_MATCHER_P(polymorphicHas,
                           AST_POLYMORPHIC_SUPPORTED_TYPES(Decl, Stmt),
                           internal::Matcher<Decl>, AMatcher) {
   return Finder->matchesChildOf(
       Node, AMatcher, Builder,
-      ASTMatchFinder::TK_IgnoreImplicitCastsAndParentheses,
+      ast_type_traits::TraversalKind::TK_IgnoreImplicitCastsAndParentheses,
       ASTMatchFinder::BK_First);
 }
 
 TEST(AstPolymorphicMatcherPMacro, Works) {
   DeclarationMatcher HasClassB =
       polymorphicHas(recordDecl(hasName("B")).bind("b"));
 
   EXPECT_TRUE(matchAndVerifyResultTrue("class A { class B {}; };",