[ASTMatchers] Add traversal-kind support to DynTypedMatcher

Summary:
This patch exposes `TraversalKind` support in the `DynTypedMatcher` API. While
previously, the `match` method supported traversal logic, it was not possible to
set or get the traversal kind.

Reviewers: gribozavr, steveire

Subscribers: hokein, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80685

clang/include/clang/ASTMatchers/ASTMatchersInternal.h

@@ -395,6 +395,12 @@ public:
   ///   restricts the node types for \p Kind.
   DynTypedMatcher dynCastTo(const ASTNodeKind Kind) const;
 
+  /// Return a matcher that that points to the same implementation, but sets the
+  ///   traversal kind.
+  ///
+  /// If the traversal kind is already set, then \c TK overrides it.
+  DynTypedMatcher withTraversalKind(TraversalKind TK);
+
   /// Returns true if the matcher matches the given \c DynNode.
   bool matches(const DynTypedNode &DynNode, ASTMatchFinder *Finder,
                BoundNodesTreeBuilder *Builder) const;
@@ -458,6 +464,14 @@ public:
   /// If it is not compatible, then this matcher will never match anything.
   template <typename T> Matcher<T> unconditionalConvertTo() const;
 
+  /// Returns the \c TraversalKind respected by calls to `match()`, if any.
+  ///
+  /// Most matchers will not have a traversal kind set, instead relying on the
+  /// surrounding context. For those, \c llvm::None is returned.
+  llvm::Optional<clang::TraversalKind> getTraversalKind() const {
+    return Implementation->TraversalKind();
+  }
+
 private:
   DynTypedMatcher(ASTNodeKind SupportedKind, ASTNodeKind RestrictKind,
                   IntrusiveRefCntPtr<DynMatcherInterface> Implementation)

clang/lib/ASTMatchers/ASTMatchersInternal.cpp

@@ -136,6 +136,31 @@ public:
   }
 };
 
+/// A matcher that specifies a particular \c TraversalKind.
+///
+/// The kind provided to the constructor overrides any kind that may be
+/// specified by the `InnerMatcher`.
+class DynTraversalMatcherImpl : public DynMatcherInterface {
+public:
+  explicit DynTraversalMatcherImpl(
+      clang::TraversalKind TK,
+      IntrusiveRefCntPtr<DynMatcherInterface> InnerMatcher)
+      : TK(TK), InnerMatcher(std::move(InnerMatcher)) {}
+
+  bool dynMatches(const DynTypedNode &DynNode, ASTMatchFinder *Finder,
+                  BoundNodesTreeBuilder *Builder) const override {
+    return this->InnerMatcher->dynMatches(DynNode, Finder, Builder);
+  }
+
+  llvm::Optional<clang::TraversalKind> TraversalKind() const override {
+    return TK;
+  }
+
+private:
+  clang::TraversalKind TK;
+  IntrusiveRefCntPtr<DynMatcherInterface> InnerMatcher;
+};
+
 } // namespace
 
 static llvm::ManagedStatic<TrueMatcherImpl> TrueMatcherInstance;
@@ -204,6 +229,14 @@ DynTypedMatcher::constructRestrictedWrapper(const DynTypedMatcher &InnerMatcher,
   return Copy;
 }
 
+DynTypedMatcher
+DynTypedMatcher::withTraversalKind(ast_type_traits::TraversalKind TK) {
+  auto Copy = *this;
+  Copy.Implementation =
+      new DynTraversalMatcherImpl(TK, std::move(Copy.Implementation));
+  return Copy;
+}
+
 DynTypedMatcher DynTypedMatcher::trueMatcher(ASTNodeKind NodeKind) {
   return DynTypedMatcher(NodeKind, NodeKind, &*TrueMatcherInstance);
 }

clang/unittests/ASTMatchers/ASTMatchersInternalTest.cpp

@@ -13,10 +13,12 @@
 #include "clang/Tooling/Tooling.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Support/Host.h"
+#include "llvm/Testing/Support/SupportHelpers.h"
 #include "gtest/gtest.h"
 
 namespace clang {
 namespace ast_matchers {
+using internal::DynTypedMatcher;
 
 #if GTEST_HAS_DEATH_TEST
 TEST(HasNameDeathTest, DiesOnEmptyName) {
@@ -171,6 +173,26 @@ TEST(Matcher, matchOverEntireASTContext) {
   EXPECT_NE(nullptr, PT);
 }
 
+TEST(DynTypedMatcherTest, TraversalKindForwardsToImpl) {
+  auto M = DynTypedMatcher(decl());
+  EXPECT_FALSE(M.getTraversalKind().hasValue());
+
+  M = DynTypedMatcher(traverse(TK_AsIs, decl()));
+  EXPECT_THAT(M.getTraversalKind(), llvm::ValueIs(TK_AsIs));
+}
+
+TEST(DynTypedMatcherTest, ConstructWithTraversalKindSetsTK) {
+  auto M = DynTypedMatcher(decl()).withTraversalKind(TK_AsIs);
+  EXPECT_THAT(M.getTraversalKind(), llvm::ValueIs(TK_AsIs));
+}
+
+TEST(DynTypedMatcherTest, ConstructWithTraversalKindOverridesNestedTK) {
+  auto M = DynTypedMatcher(decl()).withTraversalKind(TK_AsIs).withTraversalKind(
+      TK_IgnoreUnlessSpelledInSource);
+  EXPECT_THAT(M.getTraversalKind(),
+              llvm::ValueIs(TK_IgnoreUnlessSpelledInSource));
+}
+
 TEST(IsInlineMatcher, IsInline) {
   EXPECT_TRUE(matches("void g(); inline void f();",
                       functionDecl(isInline(), hasName("f"))));

clang/unittests/ASTMatchers/CMakeLists.txt

@@ -30,4 +30,9 @@ clang_target_link_libraries(ASTMatchersTests
   clangTooling
   )
 
+target_link_libraries(ASTMatchersTests
+  PRIVATE
+  LLVMTestingSupport
+)
+
 add_subdirectory(Dynamic)