[AST] No longer visiting CXXMethodDecl bodies created by compiler when method was...

Summary:
Clang generates function bodies and puts them in the AST for default methods if it is defaulted outside the class definition.

`
struct A {
   A &operator=(A &&O);
};

A &A::operator=(A &&O) = default;
`

This will generate a function body for the `A &A::operator=(A &&O)` and put it in the AST. This body should not be visited if implicit code is not visited as it is implicit.

This was causing SemanticHighlighting in clangd to generate duplicate tokens and putting them in weird places.

Reviewers: hokein, ilya-biryukov, gribozavr

Subscribers: mgorny, jkorous, arphaman, kadircet, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D65938

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@368402 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/AST/RecursiveASTVisitor.h b/include/clang/AST/RecursiveASTVisitor.h
index 918e5b084d928cac7cca7412547382558f0f5ee9..924cf832a8a7c7b81e2b7ab6362ba1090b41938b 100644 (file)
--- a/include/clang/AST/RecursiveASTVisitor.h
+++ b/include/clang/AST/RecursiveASTVisitor.h
@@ -2027,7 +2027,13 @@ bool RecursiveASTVisitor<Derived>::TraverseFunctionHelper(FunctionDecl *D) {
     }
   }
 
-  if (D->isThisDeclarationADefinition()) {
+  bool VisitBody = D->isThisDeclarationADefinition();
+  // If a method is set to default outside the class definition the compiler
+  // generates the method body and adds it to the AST.
+  if (const auto *MD = dyn_cast<CXXMethodDecl>(D))
+    VisitBody &= !MD->isDefaulted() || getDerived().shouldVisitImplicitCode();
+
+  if (VisitBody) {
     TRY_TO(TraverseStmt(D->getBody())); // Function body.
   }
   return true;

diff --git a/unittests/Tooling/CMakeLists.txt b/unittests/Tooling/CMakeLists.txt
index 99a3e0f209f1021cbdad1131c5250745fb504447..c699d41c2846e82cc8f881bc71b169a0f1f5081f 100644 (file)
--- a/unittests/Tooling/CMakeLists.txt
+++ b/unittests/Tooling/CMakeLists.txt
@@ -28,6 +28,7 @@ add_clang_unittest(ToolingTests
   RecursiveASTVisitorTests/ConstructExpr.cpp
   RecursiveASTVisitorTests/CXXBoolLiteralExpr.cpp
   RecursiveASTVisitorTests/CXXMemberCall.cpp
+  RecursiveASTVisitorTests/CXXMethodDecl.cpp
   RecursiveASTVisitorTests/CXXOperatorCallExprTraverser.cpp
   RecursiveASTVisitorTests/DeclRefExpr.cpp
   RecursiveASTVisitorTests/ImplicitCtor.cpp

diff --git a/unittests/Tooling/RecursiveASTVisitorTests/CXXMethodDecl.cpp b/unittests/Tooling/RecursiveASTVisitorTests/CXXMethodDecl.cpp
new file mode 100644 (file)
index 0000000..6441ea9
--- /dev/null
+++ b/unittests/Tooling/RecursiveASTVisitorTests/CXXMethodDecl.cpp
@@ -0,0 +1,58 @@
+//=------ unittest/Tooling/RecursiveASTVisitorTests/CXXMethodDecl.cpp ------=//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "TestVisitor.h"
+#include "clang/AST/Expr.h"
+
+using namespace clang;
+
+namespace {
+
+class CXXMethodDeclVisitor
+    : public ExpectedLocationVisitor<CXXMethodDeclVisitor> {
+public:
+  CXXMethodDeclVisitor(bool VisitImplicitCode)
+      : VisitImplicitCode(VisitImplicitCode) {}
+
+  bool shouldVisitImplicitCode() const { return VisitImplicitCode; }
+
+  bool VisitDeclRefExpr(DeclRefExpr *D) {
+    Match("declref", D->getLocation());
+    return true;
+  }
+  bool VisitParmVarDecl(ParmVarDecl *P) {
+    Match("parm", P->getLocation());
+    return true;
+  }
+
+private:
+  bool VisitImplicitCode;
+};
+
+TEST(RecursiveASTVisitor, CXXMethodDeclNoDefaultBodyVisited) {
+  for (bool VisitImplCode : {false, true}) {
+    CXXMethodDeclVisitor Visitor(VisitImplCode);
+    if (VisitImplCode)
+      Visitor.ExpectMatch("declref", 8, 28);
+    else
+      Visitor.DisallowMatch("declref", 8, 28);
+
+    Visitor.ExpectMatch("parm", 8, 27);
+    llvm::StringRef Code = R"cpp(
+      struct B {};
+      struct A {
+        B BB;
+        A &operator=(A &&O);
+      };
+
+      A &A::operator=(A &&O) = default;
+    )cpp";
+    EXPECT_TRUE(Visitor.runOver(Code, CXXMethodDeclVisitor::Lang_CXX11));
+  }
+}
+} // end anonymous namespace