1 files changed, 26 insertions, 6 deletions
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index a6c52b7d4b2b..8f19edbc4f36 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1984,10 +1984,27 @@ NamedDecl *Sema::LazilyCreateBuiltin(IdentifierInfo *II, unsigned ID,
   ASTContext::GetBuiltinTypeError Error;
   QualType R = Context.GetBuiltinType(ID, Error);
   if (Error) {
-    if (ForRedeclaration)
-      Diag(Loc, diag::warn_implicit_decl_requires_sysheader)
-          << getHeaderName(Context.BuiltinInfo, ID, Error)
+    if (!ForRedeclaration)
+      return nullptr;
+
+    // If we have a builtin without an associated type we should not emit a
+    // warning when we were not able to find a type for it.
+    if (Error == ASTContext::GE_Missing_type)
+      return nullptr;
+
+    // If we could not find a type for setjmp it is because the jmp_buf type was
+    // not defined prior to the setjmp declaration.
+    if (Error == ASTContext::GE_Missing_setjmp) {
+      Diag(Loc, diag::warn_implicit_decl_no_jmp_buf)
           << Context.BuiltinInfo.getName(ID);
+      return nullptr;
+    }
+
+    // Generally, we emit a warning that the declaration requires the
+    // appropriate header.
+    Diag(Loc, diag::warn_implicit_decl_requires_sysheader)
+        << getHeaderName(Context.BuiltinInfo, ID, Error)
+        << Context.BuiltinInfo.getName(ID);
     return nullptr;
   }
 
@@ -11527,9 +11544,12 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit) {
   // Check for self-references within variable initializers.
   // Variables declared within a function/method body (except for references)
   // are handled by a dataflow analysis.
-  if (!VDecl->hasLocalStorage() || VDecl->getType()->isRecordType() ||
-      VDecl->getType()->isReferenceType()) {
-    CheckSelfReference(*this, RealDecl, Init, DirectInit);
+  // This is undefined behavior in C++, but valid in C.
+  if (getLangOpts().CPlusPlus) {
+    if (!VDecl->hasLocalStorage() || VDecl->getType()->isRecordType() ||
+        VDecl->getType()->isReferenceType()) {
+      CheckSelfReference(*this, RealDecl, Init, DirectInit);
+    }
   }
 
   // If the type changed, it means we had an incomplete type that was