diff --git a/storage/innobase/include/data0data.h b/storage/innobase/include/data0data.h
index fbbdd3b8f2d..706d65a4469 100644
--- a/storage/innobase/include/data0data.h
+++ b/storage/innobase/include/data0data.h
@@ -168,7 +168,7 @@ dfield_data_is_binary_equal(
 	const dfield_t*	field,	/*!< in: field */
 	ulint		len,	/*!< in: data length or UNIV_SQL_NULL */
 	const byte*	data)	/*!< in: data */
-	MY_ATTRIBUTE((nonnull, warn_unused_result));
+	MY_ATTRIBUTE((nonnull(1), warn_unused_result));
 
 /*********************************************************************//**
 Gets info bits in a data tuple.
diff --git a/storage/innobase/include/data0data.ic b/storage/innobase/include/data0data.ic
index be0186d53fe..92be8f8c589 100644
--- a/storage/innobase/include/data0data.ic
+++ b/storage/innobase/include/data0data.ic
@@ -225,7 +225,7 @@ dfield_data_is_binary_equal(
 {
 	ut_ad(len != UNIV_SQL_DEFAULT);
 	return(len == dfield_get_len(field)
-	       && (len == UNIV_SQL_NULL
+	       && (!len || len == UNIV_SQL_NULL
 		   || !memcmp(dfield_get_data(field), data, len)));
 }
 
diff --git a/storage/innobase/include/mem0mem.h b/storage/innobase/include/mem0mem.h
index 6d0f95cba19..fa22b3d3086 100644
--- a/storage/innobase/include/mem0mem.h
+++ b/storage/innobase/include/mem0mem.h
@@ -237,7 +237,10 @@ inline
 void*
 mem_heap_dup(mem_heap_t* heap, const void* data, size_t len)
 {
-	return(memcpy(mem_heap_alloc(heap, len), data, len));
+	ut_ad(data || !len);
+	return UNIV_LIKELY(data != NULL)
+		? memcpy(mem_heap_alloc(heap, len), data, len)
+		: NULL;
 }
 
 /** Duplicate a NUL-terminated string, allocated from a memory heap.
diff --git a/storage/innobase/include/rem0rec.h b/storage/innobase/include/rem0rec.h
index 54f50058140..0c49c223e10 100644
--- a/storage/innobase/include/rem0rec.h
+++ b/storage/innobase/include/rem0rec.h
@@ -983,7 +983,7 @@ rec_init_offsets_temp(
 	ulint			n_core,
 	const dict_col_t::def_t*def_val,
 	rec_comp_status_t	status = REC_STATUS_ORDINARY)
-	MY_ATTRIBUTE((nonnull));
+	MY_ATTRIBUTE((nonnull(1,2,3)));
 /** Determine the offset to each field in temporary file.
 @param[in]	rec	temporary file record
 @param[in]	index	index of that the record belongs to
diff --git a/storage/innobase/mem/mem0mem.cc b/storage/innobase/mem/mem0mem.cc
index 929bffb881c..759308faac8 100644
--- a/storage/innobase/mem/mem0mem.cc
+++ b/storage/innobase/mem/mem0mem.cc
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2014, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2018, MariaDB Corporation.
+Copyright (c) 2017, 2019, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
diff --git a/storage/innobase/trx/trx0rec.cc b/storage/innobase/trx/trx0rec.cc
index 44b9f056770..901dd90c005 100644
--- a/storage/innobase/trx/trx0rec.cc
+++ b/storage/innobase/trx/trx0rec.cc
@@ -421,9 +421,15 @@ trx_undo_report_insert_virtual(
 
 			const dfield_t* vfield = dtuple_get_nth_v_field(
 				row, col->v_pos);
-			ulint	flen = vfield->len;
+			switch (ulint flen = vfield->len) {
+			case 0: case UNIV_SQL_NULL:
+				if (trx_undo_left(undo_block, *ptr) < 5) {
+					return(false);
+				}
 
-			if (flen != UNIV_SQL_NULL) {
+				*ptr += mach_write_compressed(*ptr, flen);
+				break;
+			default:
 				ulint	max_len
 					= dict_max_v_field_len_store_undo(
 						table, col_no);
@@ -438,14 +444,8 @@ trx_undo_report_insert_virtual(
 				}
 				*ptr += mach_write_compressed(*ptr, flen);
 
-				ut_memcpy(*ptr, vfield->data, flen);
+				memcpy(*ptr, vfield->data, flen);
 				*ptr += flen;
-			} else {
-				if (trx_undo_left(undo_block, *ptr) < 5) {
-					return(false);
-				}
-
-				*ptr += mach_write_compressed(*ptr, flen);
 			}
 		}
 	}
@@ -524,13 +524,16 @@ trx_undo_page_report_insert(
 
 		ptr += mach_write_compressed(ptr, flen);
 
-		if (flen != UNIV_SQL_NULL) {
+		switch (flen) {
+		case 0: case UNIV_SQL_NULL:
+			break;
+		default:
 			if (trx_undo_left(undo_block, ptr) < flen) {
 
 				return(0);
 			}
 
-			ut_memcpy(ptr, dfield_get_data(field), flen);
+			memcpy(ptr, dfield_get_data(field), flen);
 			ptr += flen;
 		}
 	}
@@ -998,7 +1001,7 @@ trx_undo_page_report_modify(
 				return(0);
 			}
 
-			ut_memcpy(ptr, field, flen);
+			memcpy(ptr, field, flen);
 			ptr += flen;
 		}
 	}
@@ -1129,7 +1132,7 @@ trx_undo_page_report_modify(
 					return(0);
 				}
 
-				ut_memcpy(ptr, field, flen);
+				memcpy(ptr, field, flen);
 				ptr += flen;
 			}
 
@@ -1154,7 +1157,7 @@ trx_undo_page_report_modify(
 						return(0);
 					}
 
-					ut_memcpy(ptr, field, flen);
+					memcpy(ptr, field, flen);
 					ptr += flen;
 				}
 			}
@@ -1303,7 +1306,7 @@ trx_undo_page_report_modify(
 						return(0);
 					}
 
-					ut_memcpy(ptr, field, flen);
+					memcpy(ptr, field, flen);
 					ptr += flen;
 				}
 
@@ -1388,13 +1391,16 @@ already_logged:
 
 				ptr += mach_write_compressed(ptr, flen);
 
-				if (flen != UNIV_SQL_NULL) {
+				switch (flen) {
+				case 0: case UNIV_SQL_NULL:
+					break;
+				default:
 					if (trx_undo_left(undo_block, ptr)
 					    < flen) {
 						return(0);
 					}
 
-					ut_memcpy(ptr, field, flen);
+					memcpy(ptr, field, flen);
 					ptr += flen;
 				}
 			}