1 files changed, 49 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 031f8dbb38c..d2a2bb20206 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -3946,6 +3946,53 @@ Sema::BuildMemInitializer(Decl *ConstructorD,
   return BuildBaseInitializer(BaseType, TInfo, Init, ClassDecl, EllipsisLoc);
 }
 
+/// Checks a member initializer expression for cases where reference (or
+/// pointer) members are bound to by-value parameters (or their addresses).
+static void CheckForDanglingReferenceOrPointer(Sema &S, ValueDecl *Member,
+                                               Expr *Init,
+                                               SourceLocation IdLoc) {
+  QualType MemberTy = Member->getType();
+
+  // We only handle pointers and references currently.
+  // FIXME: Would this be relevant for ObjC object pointers? Or block pointers?
+  if (!MemberTy->isReferenceType() && !MemberTy->isPointerType())
+    return;
+
+  const bool IsPointer = MemberTy->isPointerType();
+  if (IsPointer) {
+    if (const UnaryOperator *Op
+          = dyn_cast<UnaryOperator>(Init->IgnoreParenImpCasts())) {
+      // The only case we're worried about with pointers requires taking the
+      // address.
+      if (Op->getOpcode() != UO_AddrOf)
+        return;
+
+      Init = Op->getSubExpr();
+    } else {
+      // We only handle address-of expression initializers for pointers.
+      return;
+    }
+  }
+
+  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Init->IgnoreParens())) {
+    // We only warn when referring to a non-reference parameter declaration.
+    const ParmVarDecl *Parameter = dyn_cast<ParmVarDecl>(DRE->getDecl());
+    if (!Parameter || Parameter->getType()->isReferenceType())
+      return;
+
+    S.Diag(Init->getExprLoc(),
+           IsPointer ? diag::warn_init_ptr_member_to_parameter_addr
+                     : diag::warn_bind_ref_member_to_parameter)
+      << Member << Parameter << Init->getSourceRange();
+  } else {
+    // Other initializers are fine.
+    return;
+  }
+
+  S.Diag(Member->getLocation(), diag::note_ref_or_ptr_member_declared_here)
+    << (unsigned)IsPointer;
+}
+
 MemInitResult
 Sema::BuildMemberInitializer(ValueDecl *Member, Expr *Init,
                              SourceLocation IdLoc) {
@@ -4000,6 +4047,8 @@ Sema::BuildMemberInitializer(ValueDecl *Member, Expr *Init,
     if (MemberInit.isInvalid())
       return true;
 
+    CheckForDanglingReferenceOrPointer(*this, Member, MemberInit.get(), IdLoc);
+
     // C++11 [class.base.init]p7:
     //   The initialization of each base and member constitutes a
     //   full-expression.