[PATCH] D80288: [AST] default implementation is possible for non-member functions in C++2a.

[Haojian Wu via Phabricator via cfe-commits]

hokein created this revision.
hokein added a reviewer: sammccall.
Herald added a project: clang.

Make RAV not visit the default function decl by default.
Also update some stale comments on FunctionDecl::isDefault.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D80288

Files:
  clang/include/clang/AST/Decl.h
  clang/include/clang/AST/RecursiveASTVisitor.h
  clang/unittests/Tooling/RecursiveASTVisitorTests/CXXMethodDecl.cpp


Index: clang/unittests/Tooling/RecursiveASTVisitorTests/CXXMethodDecl.cpp
===================================================================
--- clang/unittests/Tooling/RecursiveASTVisitorTests/CXXMethodDecl.cpp
+++ clang/unittests/Tooling/RecursiveASTVisitorTests/CXXMethodDecl.cpp
@@ -55,4 +55,22 @@
     EXPECT_TRUE(Visitor.runOver(Code, CXXMethodDeclVisitor::Lang_CXX11));
   }
 }
+
+TEST(RecursiveASTVisitor, FunctionDeclNoDefaultBodyVisited) {
+  for (bool VisitImplCode : {false, true}) {
+    CXXMethodDeclVisitor Visitor(VisitImplCode);
+    if (VisitImplCode)
+      Visitor.ExpectMatch("declref", 4, 58, /*Times=*/2);
+    else
+      Visitor.DisallowMatch("declref", 4, 58);
+    llvm::StringRef Code = R"cpp(
+      struct s {
+        int x;
+        friend auto operator==(s a, s b) -> bool = default;
+      };
+      bool k = s() == s(); // make sure clang generates the "==" definition.
+    )cpp";
+    EXPECT_TRUE(Visitor.runOver(Code, CXXMethodDeclVisitor::Lang_CXX2a));
+  }
+}
 } // end anonymous namespace
Index: clang/include/clang/AST/RecursiveASTVisitor.h
===================================================================
--- clang/include/clang/AST/RecursiveASTVisitor.h
+++ clang/include/clang/AST/RecursiveASTVisitor.h
@@ -2103,11 +2103,11 @@
     }
   }
 
-  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();
+  bool VisitBody =
+      D->isThisDeclarationADefinition() &&
+      // Don't visit the function body if the function definition is generated
+      // by clang.
+      (!D->isDefaulted() || getDerived().shouldVisitImplicitCode());
 
   if (VisitBody) {
     TRY_TO(TraverseStmt(D->getBody())); // Function body.
Index: clang/include/clang/AST/Decl.h
===================================================================
--- clang/include/clang/AST/Decl.h
+++ clang/include/clang/AST/Decl.h
@@ -2125,19 +2125,18 @@
   bool isTrivialForCall() const { return FunctionDeclBits.IsTrivialForCall; }
   void setTrivialForCall(bool IT) { FunctionDeclBits.IsTrivialForCall = IT; }
 
-  /// Whether this function is defaulted per C++0x. Only valid for
-  /// special member functions.
+  /// Whether this function is defaulted per C++0x. Valid for e.g.
+  /// special member functions, C++2a friend default comparisions
+  // (not methods!).
   bool isDefaulted() const { return FunctionDeclBits.IsDefaulted; }
   void setDefaulted(bool D = true) { FunctionDeclBits.IsDefaulted = D; }
 
-  /// Whether this function is explicitly defaulted per C++0x. Only valid
-  /// for special member functions.
+  /// Whether this function is explicitly defaulted per C++0x.
   bool isExplicitlyDefaulted() const {
     return FunctionDeclBits.IsExplicitlyDefaulted;
   }
 
-  /// State that this function is explicitly defaulted per C++0x. Only valid
-  /// for special member functions.
+  /// State that this function is explicitly defaulted per C++0x.
   void setExplicitlyDefaulted(bool ED = true) {
     FunctionDeclBits.IsExplicitlyDefaulted = ED;
   }


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