Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -2912,6 +2912,10 @@
   "%select{the protocol method it implements|its overridden method}1 is "
   "available">,
   InGroup<Availability>;
+def warn_availability_on_static_initializer : Warning<
+  "ignoring availability attribute %select{on '+load' method|"
+  "with constructor attribute|with destructor attribute}0">,
+  InGroup<Availability>;
 def note_overridden_method : Note<
   "overridden method is here">;
 def note_protocol_method : Note<
Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -9139,6 +9139,21 @@
     AddToScope = false;
   }
 
+  // Diagnose availability attributes. Availability cannot be used on functions
+  // that are run during load/unload.
+  if (const auto *attr = NewFD->getAttr<AvailabilityAttr>()) {
+    if (NewFD->hasAttr<ConstructorAttr>()) {
+      Diag(attr->getLocation(), diag::warn_availability_on_static_initializer)
+          << 1;
+      NewFD->dropAttr<AvailabilityAttr>();
+    }
+    if (NewFD->hasAttr<DestructorAttr>()) {
+      Diag(attr->getLocation(), diag::warn_availability_on_static_initializer)
+          << 2;
+      NewFD->dropAttr<AvailabilityAttr>();
+    }
+  }
+
   return NewFD;
 }
 
Index: lib/Sema/SemaDeclAttr.cpp
===================================================================
--- lib/Sema/SemaDeclAttr.cpp
+++ lib/Sema/SemaDeclAttr.cpp
@@ -6823,6 +6823,12 @@
       return false;
 
     // An implementation implicitly has the availability of the interface.
+    // Unless it is "+load" method.
+    if (const auto *MethodD = dyn_cast<ObjCMethodDecl>(Ctx))
+      if (MethodD->isClassMethod() &&
+          MethodD->getSelector().getAsString() == "load")
+        return true;
+
     if (const auto *CatOrImpl = dyn_cast<ObjCImplDecl>(Ctx)) {
       if (const ObjCInterfaceDecl *Interface = CatOrImpl->getClassInterface())
         if (CheckContext(Interface))
Index: lib/Sema/SemaDeclObjC.cpp
===================================================================
--- lib/Sema/SemaDeclObjC.cpp
+++ lib/Sema/SemaDeclObjC.cpp
@@ -4734,6 +4734,17 @@
       Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86)
     checkObjCMethodX86VectorTypes(*this, ObjCMethod);
 
+  // + load method cannot have availability attributes. It get called on
+  // startup, so it has to have the availability of the deployment target.
+  if (const auto *attr = ObjCMethod->getAttr<AvailabilityAttr>()) {
+    if (ObjCMethod->isClassMethod() &&
+        ObjCMethod->getSelector().getAsString() == "load") {
+      Diag(attr->getLocation(), diag::warn_availability_on_static_initializer)
+          << 0;
+      ObjCMethod->dropAttr<AvailabilityAttr>();
+    }
+  }
+
   ActOnDocumentableDecl(ObjCMethod);
 
   return ObjCMethod;
Index: test/SemaObjC/unguarded-availability.m
===================================================================
--- test/SemaObjC/unguarded-availability.m
+++ test/SemaObjC/unguarded-availability.m
@@ -7,7 +7,7 @@
 
 typedef int AVAILABLE_10_12 new_int; // expected-note + {{marked partial here}}
 
-int func_10_11() AVAILABLE_10_11; // expected-note 4 {{'func_10_11' has been explicitly marked partial here}}
+int func_10_11() AVAILABLE_10_11; // expected-note 8 {{'func_10_11' has been explicitly marked partial here}}
 
 #ifdef OBJCPP
 // expected-note@+2 6 {{marked partial here}}
@@ -311,3 +311,45 @@
   (void)AK_Cat; // no warning
   (void)AK_CyborgCat; // expected-warning{{'AK_CyborgCat' is only available on macOS 10.12 or newer}} expected-note {{@available}}
 }
+
+
+// test static initializers has the same availability as the deployment target and it cannot be overwritten.
+@interface HasStaticInitializer : BaseClass
++ (void)load AVAILABLE_10_11; // expected-warning{{ignoring availability attribute on '+load' method}}
+@end
+
+@implementation HasStaticInitializer
++ (void)load {
+  func_10_11(); // expected-warning{{'func_10_11' is only available on macOS 10.11 or newer}} expected-note{{enclose 'func_10_11' in an @available check to silence this warning}}
+}
+@end
+
+// test availability from interface is ignored when checking the unguarded availability in +load method.
+AVAILABLE_10_11
+@interface HasStaticInitializer1 : BaseClass
++ (void)load;
++ (void)load: (int)x; // no warning.
+@end
+
+@implementation HasStaticInitializer1
++ (void)load {
+  func_10_11(); // expected-warning{{'func_10_11' is only available on macOS 10.11 or newer}} expected-note{{enclose 'func_10_11' in an @available check to silence this warning}}
+}
++ (void)load: (int)x {
+  func_10_11(); // no warning.
+}
+@end
+
+__attribute__((constructor))
+void is_constructor();
+
+AVAILABLE_10_11 // expected-warning{{ignoring availability attribute with constructor attribute}}
+void is_constructor() {
+  func_10_11(); // expected-warning{{'func_10_11' is only available on macOS 10.11 or newer}} expected-note{{enclose 'func_10_11' in an @available check to silence this warning}}
+}
+
+AVAILABLE_10_11 // expected-warning{{ignoring availability attribute with destructor attribute}}
+__attribute__((destructor))
+void is_destructor() {
+  func_10_11(); // expected-warning{{'func_10_11' is only available on macOS 10.11 or newer}} expected-note{{enclose 'func_10_11' in an @available check to silence this warning}}
+}