[PATCH] D26119: [clang-tidy] Handle bitfields in cppcoreguidelines-pro-type-member-init

[Malcolm Parsons via cfe-commits]

malcolm.parsons created this revision.
malcolm.parsons added reviewers: aaron.ballman, alexfh.
malcolm.parsons added a subscriber: cfe-commits.
Herald added a subscriber: nemanjai.

Unnamed bitfields cannot be initialized.
Bitfields cannot be in-class initialized.


https://reviews.llvm.org/D26119

Files:
  clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
  test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp


Index: test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp
===================================================================
--- test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp
+++ test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp
@@ -456,3 +456,20 @@
     template <typename U> B(U u) {}
   };
 };
+
+struct PositiveBitfieldMember {
+  PositiveBitfieldMember() {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these fields: F
+  unsigned F : 5;
+};
+
+struct NegativeUnnamedBitfieldMember {
+  NegativeUnnamedBitfieldMember() {}
+  unsigned : 5;
+};
+
+struct NegativeInitializedBitfieldMembers {
+  NegativeInitializedBitfieldMembers() : F(3) { G = 2; }
+  unsigned F : 5;
+  unsigned G : 5;
+};
Index: clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
===================================================================
--- clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
+++ clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
@@ -358,7 +358,7 @@
     if (!F->hasInClassInitializer() &&
         utils::type_traits::isTriviallyDefaultConstructible(F->getType(),
                                                             Context) &&
-        !isEmpty(Context, F->getType()))
+        !isEmpty(Context, F->getType()) && !F->isUnnamedBitfield())
       FieldsToInit.insert(F);
   });
   if (FieldsToInit.empty())
@@ -407,7 +407,9 @@
   SmallPtrSet<const FieldDecl *, 16> FieldsToFix;
   forEachField(ClassDecl, FieldsToInit, true, [&](const FieldDecl *F) {
     // Don't suggest fixes for enums because we don't know a good default.
-    if (!F->getType()->isEnumeralType())
+    // Don't suggest fixes for bitfields because in-class initialization is not
+    // possible.
+    if (!F->getType()->isEnumeralType() && !F->isBitField())
       FieldsToFix.insert(F);
   });
   if (FieldsToFix.empty())


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