Pass #1 at localizing assumptions about fixed layout and

handling non-fixed layouts.

This uncovered a bug where we weren't rounding up the header
size to the element alignment when allocating an array of archetypes.

Writing up a detailed test case for *that* revealed that we were
never initializing the length field of heap arrays.  Fixing that
caused a bunch of tests to crash trying to release stuff.  So...
I've left this in a workaround state right now because I have to
catch a plane.

Swift SVN r4804

lib/IRGen/IRGenModule.cpp

@@ -286,6 +286,17 @@ llvm::Constant *IRGenModule::getSlowRawDeallocFn() {
   return SlowRawDeallocFn;
 }
 
+llvm::Constant *IRGenModule::getCopyPODFn() {
+  if (CopyPODFn) return CopyPODFn;
+
+  /// void *swift_copyPOD(void *dest, void *src, Metadata *self);
+  llvm::Type *types[] = { OpaquePtrTy, OpaquePtrTy,  };
+  llvm::FunctionType *fnType =
+    llvm::FunctionType::get(OpaquePtrTy, types, false);
+  CopyPODFn = createRuntimeFunction(*this, "swift_copyPOD", fnType);
+  return CopyPODFn;
+}
+
 llvm::Constant *IRGenModule::getDynamicCastClassFn() {
   if (DynamicCastClassFn) return DynamicCastClassFn;
 
@@ -498,6 +509,10 @@ llvm::Constant *IRGenModule::getObjCEmptyVTablePtr() {
   return ObjCEmptyVTablePtr;
 }
 
+llvm::Constant *IRGenModule::getSize(Size size) {
+  return llvm::ConstantInt::get(SizeTy, size.getValue());
+}
+
 void IRGenModule::unimplemented(SourceLoc loc, StringRef message) {
   Context.Diags.diagnose(loc, diag::irgen_unimplemented, message);
 }