diff --git a/src/gen-ucd-table.py b/src/gen-ucd-table.py
index 967e000d4..c98c715e1 100755
--- a/src/gen-ucd-table.py
+++ b/src/gen-ucd-table.py
@@ -3,19 +3,22 @@
 from __future__ import print_function, division, absolute_import
 
 import io, os.path, sys, re
+import logging
+logging.basicConfig(format='%(levelname)s: %(message)s', level=logging.INFO)
 
 if len (sys.argv) != 2:
 	print("usage: ./gen-ucd-table ucd.nonunihan.grouped.xml", file=sys.stderr)
 	sys.exit(1)
 
-
 # https://github.com/harfbuzz/packtab
 import packTab
 import packTab.ucdxml
 
+logging.info('Loading UCDXML...')
 ucdxml = packTab.ucdxml.load_ucdxml(sys.argv[1])
 ucd = packTab.ucdxml.ucdxml_get_repertoire(ucdxml)
 
+logging.info('Preparing data tables...')
 
 gc = [u['gc'] for u in ucd]
 ccc = [int(u['ccc']) for u in ucd]
@@ -71,6 +74,7 @@ DEFAULT = 1
 COMPACT = 3
 
 
+logging.info('Generating output...')
 print("/* == Start of generated table == */")
 print("/*")
 print(" * The following table is generated by running:")
@@ -82,8 +86,6 @@ print(" */")
 print()
 print("#ifndef HB_UCD_TABLE_HH")
 print("#define HB_UCD_TABLE_HH")
-print()
-
 print()
 print('#include "hb.hh"')
 print()
@@ -95,7 +97,16 @@ dm1_32_array, _ = code.addArray('uint32_t', 'dm1_u32_map', dm1_u32_array)
 dm2_array, _ = code.addArray('uint64_t', 'dm2_map', dm2_array)
 code.print_c(linkage='static inline')
 
+datasets = [
+    ('gc', gc, 'Cn', gc_order),
+    ('ccc', ccc, 0, None),
+    ('bmg', bmg, 0, None),
+    ('sc', sc, 'Zzzz', sc_order),
+    ('dm', dm, None, dm_order),
+]
+
 for compression in (DEFAULT, COMPACT):
+    logging.info('  Compression=%d:' % compression)
     print()
     if compression == DEFAULT:
         print('#ifndef HB_OPTIMIZE_SIZE')
@@ -105,11 +116,10 @@ for compression in (DEFAULT, COMPACT):
 
     code = packTab.Code('_hb_ucd')
 
-    packTab.pack_table(gc, 'Cn', mapping=gc_order, compression=compression).genCode(code, 'gc')
-    packTab.pack_table(ccc, 0, compression=compression).genCode(code, 'ccc')
-    packTab.pack_table(bmg, 0, compression=compression).genCode(code, 'bmg')
-    packTab.pack_table(sc, 'Zzzz', mapping=sc_order, compression=compression).genCode(code, 'sc')
-    packTab.pack_table(dm, None, mapping=dm_order, compression=compression).genCode(code, 'dm')
+    for name,data,default,mapping in datasets:
+        sol = packTab.pack_table(data, default, mapping=mapping, compression=compression)
+        logging.info('      Dataset=%-8s FullCost=%d' % (name, sol.fullCost))
+        sol.genCode(code, name)
 
     code.print_c(linkage='static inline')
 
@@ -123,3 +133,4 @@ print()
 print("#endif /* HB_UCD_TABLE_HH */")
 print()
 print("/* == End of generated table == */")
+logging.info('Done.')
diff --git a/src/hb-ucd-table.hh b/src/hb-ucd-table.hh
index ae339ec0c..e9d097542 100644
--- a/src/hb-ucd-table.hh
+++ b/src/hb-ucd-table.hh
@@ -10,7 +10,6 @@
 #ifndef HB_UCD_TABLE_HH
 #define HB_UCD_TABLE_HH
 
-
 #include "hb.hh"
 
 static const hb_script_t