Extend -Wtautological-undefined-compare and -Wundefined-bool-conversion to
trigger on taking the address of a reference that is returned from a function
call.
llvm-svn: 211989
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 72d3b27..1a49b4a 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -6192,6 +6192,38 @@
ArrayPointer
};
+// Helper function for Sema::DiagnoseAlwaysNonNullPointer.
+// Returns true when emitting a warning about taking the address of a reference.
+static bool CheckForReference(Sema &SemaRef, const Expr *E,
+ PartialDiagnostic PD) {
+ E = E->IgnoreParenImpCasts();
+
+ const FunctionDecl *FD = nullptr;
+
+ if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
+ if (!DRE->getDecl()->getType()->isReferenceType())
+ return false;
+ } else if (const MemberExpr *M = dyn_cast<MemberExpr>(E)) {
+ if (!M->getMemberDecl()->getType()->isReferenceType())
+ return false;
+ } else if (const CallExpr *Call = dyn_cast<CallExpr>(E)) {
+ if (!Call->getCallReturnType()->isReferenceType())
+ return false;
+ FD = Call->getDirectCallee();
+ } else {
+ return false;
+ }
+
+ SemaRef.Diag(E->getExprLoc(), PD);
+
+ // If possible, point to location of function.
+ if (FD) {
+ SemaRef.Diag(FD->getLocation(), diag::note_reference_is_return_value) << FD;
+ }
+
+ return true;
+}
+
/// \brief Diagnose pointers that are always non-null.
/// \param E the expression containing the pointer
/// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is
@@ -6227,6 +6259,17 @@
E = UO->getSubExpr();
}
+ if (IsAddressOf) {
+ unsigned DiagID = IsCompare
+ ? diag::warn_address_of_reference_null_compare
+ : diag::warn_address_of_reference_bool_conversion;
+ PartialDiagnostic PD = PDiag(DiagID) << E->getSourceRange() << Range
+ << IsEqual;
+ if (CheckForReference(*this, E, PD)) {
+ return;
+ }
+ }
+
// Expect to find a single Decl. Skip anything more complicated.
ValueDecl *D = nullptr;
if (DeclRefExpr *R = dyn_cast<DeclRefExpr>(E)) {
@@ -6243,18 +6286,9 @@
const bool IsArray = T->isArrayType();
const bool IsFunction = T->isFunctionType();
- if (IsAddressOf) {
- // Address of function is used to silence the function warning.
- if (IsFunction)
- return;
-
- if (T->isReferenceType()) {
- unsigned DiagID = IsCompare
- ? diag::warn_address_of_reference_null_compare
- : diag::warn_address_of_reference_bool_conversion;
- Diag(E->getExprLoc(), DiagID) << E->getSourceRange() << Range << IsEqual;
- return;
- }
+ // Address of function is used to silence the function warning.
+ if (IsAddressOf && IsFunction) {
+ return;
}
// Found nothing.