Revert "IRGen: Deserialize SIL witness tables and shared-linkage definitions by need."

lib/SIL/SILModule.cpp

@@ -22,7 +22,6 @@
 #include "Linker.h"
 #include "swift/SIL/SILVisitor.h"
 #include "swift/SIL/SILValue.h"
-#include "swift/ClangImporter/ClangModule.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringSwitch.h"
@@ -782,23 +781,6 @@ bool SILModule::isNoReturnBuiltinOrIntrinsic(Identifier Name) {
   }
 }
 
-bool SILModule::
-shouldSerializeEntitiesAssociatedWithDeclContext(const DeclContext *DC) const {
-  // Serialize entities associated with this module's associated context.
-  if (DC->isChildContextOf(getAssociatedContext())) {
-    return true;
-  }
-  
-  // Serialize entities associated with clang modules, since other entities
-  // may depend on them, and someone who deserializes those entities may not
-  // have their own copy.
-  if (isa<ClangModuleUnit>(DC->getModuleScopeContext())) {
-    return true;
-  }
-  
-  return false;
-}
-
 /// Returns true if it is the OnoneSupport module.
 bool SILModule::isOnoneSupportModule() const {
   return getSwiftModule()->getName().str() == SWIFT_ONONE_SUPPORT;