r268895 - Fix spurious warnings about unused private field

[Olivier Goffart via cfe-commits]

Author: ogoffart
Date: Mon May  9 02:09:51 2016
New Revision: 268895

URL: http://llvm.org/viewvc/llvm-project?rev=268895&view=rev
Log:
Fix spurious warnings about unused private field

If the address of a field is taken as a pointer to member, we should
not warn that the field is not used.

Normaly, yse of fields are done from MemberExpr, but in case of pointer to
member, it is in a DeclRefExpr

Differential Revision: http://reviews.llvm.org/D20054

Modified:
    cfe/trunk/lib/Sema/SemaExpr.cpp
    cfe/trunk/test/SemaCXX/warn-unused-private-field.cpp

Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=268895&r1=268894&r2=268895&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Mon May  9 02:09:51 2016
@@ -1736,10 +1736,12 @@ Sema::BuildDeclRefExpr(ValueDecl *D, Qua
       !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, E->getLocStart()))
       recordUseOfEvaluatedWeak(E);
 
-  // Just in case we're building an illegal pointer-to-member.
-  FieldDecl *FD = dyn_cast<FieldDecl>(D);
-  if (FD && FD->isBitField())
-    E->setObjectKind(OK_BitField);
+  if (FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
+    UnusedPrivateFields.remove(FD);
+    // Just in case we're building an illegal pointer-to-member.
+    if (FD->isBitField())
+      E->setObjectKind(OK_BitField);
+  }
 
   return E;
 }

Modified: cfe/trunk/test/SemaCXX/warn-unused-private-field.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-unused-private-field.cpp?rev=268895&r1=268894&r2=268895&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/warn-unused-private-field.cpp (original)
+++ cfe/trunk/test/SemaCXX/warn-unused-private-field.cpp Mon May  9 02:09:51 2016
@@ -128,6 +128,7 @@ class EverythingUsed {
     int *use = &by_reference_;
     int test[2];
     test[as_array_index_] = 42;
+    int EverythingUsed::*ptr = &EverythingUsed::by_pointer_to_member_;
   }
 
   template<class T>
@@ -142,6 +143,7 @@ class EverythingUsed {
   int by_template_function_;
   int as_array_index_;
   int by_initializer_;
+  int by_pointer_to_member_;
 };
 
 class HasFeatureTest {