[Sema] Packed member warning: Use the typedef name for anonymous structures

This commit improves the packed member warning by showing the name of the
anonymous structure/union when it was defined within a typedef declaration.

rdar://28498901

Differential Revision: https://reviews.llvm.org/D25106

llvm-svn: 283304

clang/lib/Sema/SemaChecking.cpp

@@ -11372,8 +11372,13 @@ void Sema::AddPotentialMisalignedMembers(Expr *E, RecordDecl *RD, ValueDecl *MD,
 
 void Sema::DiagnoseMisalignedMembers() {
   for (MisalignedMember &m : MisalignedMembers) {
+    const NamedDecl *ND = m.RD;
+    if (ND->getName().empty()) {
+      if (const TypedefNameDecl *TD = m.RD->getTypedefNameForAnonDecl())
+        ND = TD;
+    }
     Diag(m.E->getLocStart(), diag::warn_taking_address_of_packed_member)
-        << m.MD << m.RD << m.E->getSourceRange();
+        << m.MD << ND << m.E->getSourceRange();
   }
   MisalignedMembers.clear();
 }

clang/test/Sema/address-packed.c

@@ -161,3 +161,38 @@ struct AlignedTo2Bis* g7(struct AlignedTo2 *s)
 {
     return (struct AlignedTo2Bis*)&s->x; // no-warning
 }
+
+typedef struct {
+  char c;
+  int x;
+} __attribute__((packed)) TypedefStructArguable;
+
+typedef union {
+  char c;
+  int x;
+} __attribute((packed)) TypedefUnionArguable;
+
+typedef TypedefStructArguable TypedefStructArguableTheSecond;
+
+int *typedef1(TypedefStructArguable *s) {
+    return &s->x; // expected-warning {{packed member 'x' of class or structure 'TypedefStructArguable'}}
+}
+
+int *typedef2(TypedefStructArguableTheSecond *s) {
+    return &s->x; // expected-warning {{packed member 'x' of class or structure 'TypedefStructArguable'}}
+}
+
+int *typedef3(TypedefUnionArguable *s) {
+    return &s->x; // expected-warning {{packed member 'x' of class or structure 'TypedefUnionArguable'}}
+}
+
+struct S6 {
+  union {
+    char c;
+    int x;
+  } __attribute__((packed));
+};
+
+int *anonymousInnerUnion(struct S6 *s) {
+  return &s->x; // expected-warning {{packed member 'x' of class or structure 'S6::(anonymous)'}}
+}