Revert "New SIL instructions to support tail-allocated arrays in SIL."

stdlib/public/runtime/HeapObject.cpp

@@ -107,6 +107,28 @@ extern "C" HeapObject* swift_bufferAllocate(
                                                        alignMask);
 }
 
+/// \brief Another entrypoint for swift_bufferAllocate.
+/// It is generated by the compiler in some corner cases, e.g. if a serialized
+/// optimized module is imported into a non-optimized main module.
+/// TODO: This is only a workaround. Remove this function as soon as we can
+/// get rid of the llvm SwiftStackPromotion pass.
+SWIFT_RUNTIME_EXPORT
+extern "C" HeapObject* swift_bufferAllocateOnStack(
+  HeapMetadata const* bufferType, size_t size, size_t alignMask) {
+  return swift::SWIFT_RT_ENTRY_CALL(swift_allocObject)(bufferType, size,
+                                                       alignMask);
+}
+
+/// \brief Called at the end of the lifetime of an object returned by
+/// swift_bufferAllocateOnStack.
+/// It is generated by the compiler in some corner cases, e.g. if a serialized
+/// optimized module is imported into a non-optimized main module.
+/// TODO: This is only a workaround. Remove this function as soon as we can
+/// get rid of the llvm SwiftStackPromotion pass.
+SWIFT_RUNTIME_EXPORT
+extern "C" void swift_bufferDeallocateFromStack(HeapObject *) {
+}
+
 SWIFT_RUNTIME_EXPORT
 extern "C" intptr_t swift_bufferHeaderSize() { return sizeof(HeapObject); }