Introduce -Wunused-private-field. If enabled, this warning detects
unused private fields of classes that are fully defined in the current
translation unit.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158054 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 676063a..e7a2216 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -1439,6 +1439,17 @@
return true;
}
+static bool InitializationHasSideEffects(const FieldDecl &FD) {
+ if (!FD.getType().isNull()) {
+ if (const CXXRecordDecl *RD = FD.getType()->getAsCXXRecordDecl()) {
+ return !RD->isCompleteDefinition() ||
+ !RD->hasTrivialDefaultConstructor() ||
+ !RD->hasTrivialDestructor();
+ }
+ }
+ return false;
+}
+
/// ActOnCXXMemberDeclarator - This is invoked when a C++ class member
/// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the
/// bitfield width if there is one, 'InitExpr' specifies the initializer if
@@ -1624,8 +1635,23 @@
assert((Name || isInstField) && "No identifier for non-field ?");
- if (isInstField)
- FieldCollector->Add(cast<FieldDecl>(Member));
+ if (isInstField) {
+ FieldDecl *FD = cast<FieldDecl>(Member);
+ FieldCollector->Add(FD);
+
+ if (Diags.getDiagnosticLevel(diag::warn_unused_private_field,
+ FD->getLocation())
+ != DiagnosticsEngine::Ignored) {
+ // Remember all explicit private FieldDecls that have a name, no side
+ // effects and are not part of a dependent type declaration.
+ if (!FD->isImplicit() && FD->getDeclName() &&
+ FD->getAccess() == AS_private &&
+ !FD->getParent()->getTypeForDecl()->isDependentType() &&
+ !InitializationHasSideEffects(*FD))
+ UnusedPrivateFields.insert(FD);
+ }
+ }
+
return Member;
}
@@ -2105,6 +2131,25 @@
Args = InitList->getInits();
NumArgs = InitList->getNumInits();
}
+
+ // Mark FieldDecl as being used if it is a non-primitive type and the
+ // initializer does not call the default constructor (which is trivial
+ // for all entries in UnusedPrivateFields).
+ // FIXME: Make this smarter once more side effect-free types can be
+ // determined.
+ if (NumArgs > 0) {
+ if (Member->getType()->isRecordType()) {
+ UnusedPrivateFields.remove(Member);
+ } else {
+ for (unsigned i = 0; i < NumArgs; ++i) {
+ if (Args[i]->HasSideEffects(Context)) {
+ UnusedPrivateFields.remove(Member);
+ break;
+ }
+ }
+ }
+ }
+
for (unsigned i = 0; i < NumArgs; ++i) {
SourceLocation L;
if (InitExprContainsUninitializedFields(Args[i], Member, &L)) {
@@ -2808,6 +2853,13 @@
SourceLocation(), 0,
SourceLocation());
Info.AllToInit.push_back(Init);
+
+ // Check whether this initializer makes the field "used".
+ Expr *InitExpr = Field->getInClassInitializer();
+ if (Field->getType()->isRecordType() ||
+ (InitExpr && InitExpr->HasSideEffects(SemaRef.Context)))
+ SemaRef.UnusedPrivateFields.remove(Field);
+
return false;
}