[Serialization] Support factory initializers.

These never appear in Swift code, but they can appear when serializing the
full output of SILGen ("SIB" format) because that includes code synthesized
for imported Clang declarations.

rdar://problem/22098491

Swift SVN r31364

include/swift/Serialization/ModuleFormat.h

@@ -167,9 +167,11 @@ using AccessorKindField = BCFixed<3>;
 // VERSION_MAJOR.
 enum CtorInitializerKind : uint8_t {
   Designated = 0,
-  Convenience = 1
+  Convenience = 1,
+  Factory = 2,
+  ConvenienceFactory = 3,
 };
-using CtorInitializerKindField = BCFixed<1>;
+using CtorInitializerKindField = BCFixed<2>;
 
 // These IDs must \em not be renumbered or reordered without incrementing
 // VERSION_MAJOR.

lib/Serialization/Deserialization.cpp

@@ -955,11 +955,14 @@ bool ModuleFile::readMembers(SmallVectorImpl<Decl *> &Members) {
 static Optional<swift::CtorInitializerKind>
 getActualCtorInitializerKind(uint8_t raw) {
   switch (serialization::CtorInitializerKind(raw)) {
-  case serialization::Designated:
-    return swift::CtorInitializerKind::Designated;
-
-  case serialization::Convenience:
-    return swift::CtorInitializerKind::Convenience;
+#define CASE(NAME) \
+  case serialization::CtorInitializerKind::NAME: \
+    return swift::CtorInitializerKind::NAME;
+  CASE(Designated)
+  CASE(Convenience)
+  CASE(Factory)
+  CASE(ConvenienceFactory)
+#undef CASE
   }
   return None;
 }

lib/Serialization/Serialization.cpp

@@ -1257,16 +1257,12 @@ static serialization::AccessorKind getStableAccessorKind(swift::AccessorKind K){
 static serialization::CtorInitializerKind
 getStableCtorInitializerKind(swift::CtorInitializerKind K){
   switch (K) {
-  case swift::CtorInitializerKind::ConvenienceFactory:
-    llvm_unreachable("Convenience factory initializers cannot be uttered");
-
-  case swift::CtorInitializerKind::Factory:
-    llvm_unreachable("Factory initializers cannot be uttered");
-
 #define CASE(NAME) \
   case swift::CtorInitializerKind::NAME: return serialization::NAME;
       CASE(Designated)
       CASE(Convenience)
+      CASE(Factory)
+      CASE(ConvenienceFactory)
 #undef CASE
   }
 }

test/SIL/Serialization/clang_sib.swift

@@ -0,0 +1,12 @@
+// RUN: rm -rf %t && mkdir %t
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-sib -o %t -primary-file %s -module-name main
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-ir -o /dev/null -primary-file %t/clang_sib.sib -module-name main
+
+// REQUIRES: objc_interop
+
+import Foundation
+
+func test() {
+  // Use a factory initializer.
+  _ = Hive(queen: Bee())
+}