add type attribute warn_unused, for -Wunused-variable warnings (pr#14253)
The functionality is equivalent to the GCC attribute. Variables of tagged
types will be warned about as unused if they are not used in any way
except for possible (even non-trivial) ctors/dtors called. Useful for tagging
classes like std::string (which is not part of this commit).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186765 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index ef401c3..a3e05e6 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -2668,6 +2668,17 @@
Attr.getAttributeSpellingListIndex()));
}
+static void handleWarnUnusedAttr(Sema &S, Decl *D, const AttributeList &Attr) {
+ // Check the attribute arguments.
+ if (!checkAttributeNumArgs(S, Attr, 0))
+ return;
+
+ if (RecordDecl *RD = dyn_cast<RecordDecl>(D))
+ RD->addAttr(::new (S.Context) WarnUnusedAttr(Attr.getRange(), S.Context));
+ else
+ S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << Attr.getName();
+}
+
static void handleWarnUnusedResult(Sema &S, Decl *D, const AttributeList &Attr) {
// check the attribute arguments.
if (!checkAttributeNumArgs(S, Attr, 0))
@@ -4892,6 +4903,9 @@
case AttributeList::AT_TypeVisibility:
handleVisibilityAttr(S, D, Attr, true);
break;
+ case AttributeList::AT_WarnUnused:
+ handleWarnUnusedAttr(S, D, Attr);
+ break;
case AttributeList::AT_WarnUnusedResult: handleWarnUnusedResult(S, D, Attr);
break;
case AttributeList::AT_Weak: handleWeakAttr (S, D, Attr); break;