diff --git a/.circleci/config.yml b/.circleci/config.yml
index 5ad1ae135..7baebb1c8 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -79,6 +79,54 @@ jobs:
       - run: make
       - run: LD_LIBRARY_PATH="$PWD/freetype-2.9/objs/.libs" make check || .ci/fail.sh
 
+  clang-asan:
+    docker:
+      - image: ubuntu:18.04
+    steps:
+      - checkout
+      - run: apt update || true
+      - run: apt install -y clang-6.0 binutils libtool autoconf automake make pkg-config gtk-doc-tools ragel libfreetype6-dev libglib2.0-dev libcairo2-dev libicu-dev libgraphite2-dev python python-pip
+      - run: pip install fonttools
+      - run: CPPFLAGS="-fsanitize=address" LDFLAGS="-fsanitize=address" CC=clang-6.0 CXX=clang++-6.0 ./autogen.sh --with-freetype --with-glib --with-cairo --with-icu --with-graphite2
+      - run: make
+      - run: make check || .ci/fail.sh
+
+  clang-msan:
+    docker:
+      - image: ubuntu:18.04
+    steps:
+      - checkout
+      - run: apt update || true
+      - run: apt install -y clang-6.0 binutils libtool autoconf automake make pkg-config ragel libfreetype6-dev libglib2.0-dev libcairo2-dev libicu-dev libgraphite2-dev python python-pip
+      - run: pip install fonttools
+      - run: CPPFLAGS="-fsanitize=memory" LDFLAGS="-fsanitize=memory" CC=clang-6.0 CXX=clang++-6.0 ./autogen.sh --with-freetype --with-glib --with-cairo --with-icu --with-graphite2
+      - run: make
+      - run: make check || .ci/fail.sh
+
+  clang-tsan:
+    docker:
+      - image: ubuntu:18.04
+    steps:
+      - checkout
+      - run: apt update || true
+      - run: apt install -y clang-6.0 binutils libtool autoconf automake make pkg-config ragel libfreetype6-dev libglib2.0-dev libcairo2-dev libicu-dev libgraphite2-dev python python-pip
+      - run: pip install fonttools
+      - run: CPPFLAGS="-fsanitize=thread" LDFLAGS="-fsanitize=thread" CC=clang-6.0 CXX=clang++-6.0 ./autogen.sh --with-freetype --with-glib --with-cairo --with-icu --with-graphite2
+      - run: make
+      - run: make check || .ci/fail.sh
+
+  clang-ubsan:
+    docker:
+      - image: ubuntu:18.04
+    steps:
+      - checkout
+      - run: apt update || true
+      - run: apt install -y clang-6.0 binutils libtool autoconf automake make pkg-config ragel libfreetype6-dev libglib2.0-dev libcairo2-dev libicu-dev libgraphite2-dev python python-pip
+      - run: pip install fonttools
+      - run: CPPFLAGS="-fsanitize=undefined" LDFLAGS="-fsanitize=undefined" CC=clang-6.0 CXX=clang++-6.0 ./autogen.sh --with-freetype --with-glib --with-cairo --with-icu --with-graphite2
+      - run: make
+      - run: make check || .ci/fail.sh
+
   fedora-outoftreebuild:
     docker:
       - image: fedora
@@ -200,6 +248,10 @@ workflows:
       - alpine-O3-NOMMAP
       - archlinux-debug-O0-py3
       - clang-O3-O0
+      - clang-asan
+      #- clang-msan
+      - clang-tsan
+      #- clang-ubsan
       - fedora-outoftreebuild
 
       # cmake based builds
diff --git a/src/check-symbols.sh b/src/check-symbols.sh
index d4eca5079..6e9382b1a 100755
--- a/src/check-symbols.sh
+++ b/src/check-symbols.sh
@@ -26,7 +26,7 @@ for soname in harfbuzz harfbuzz-subset harfbuzz-icu harfbuzz-gobject; do
 		symprefix=
 		if test $suffix = dylib; then symprefix=_; fi
 
-		EXPORTED_SYMBOLS="`nm "$so" | grep ' [BCDGINRSTVW] .' | grep -v " $symprefix\\($IGNORED_SYMBOLS\\>\\)" | cut -d' ' -f3 | c++filt`"
+		EXPORTED_SYMBOLS="`nm "$so" | grep ' [BCDGINRSTV] .' | grep -v " $symprefix\\($IGNORED_SYMBOLS\\>\\)" | cut -d' ' -f3 | c++filt`"
 
 		prefix=$symprefix`basename "$so" | sed 's/libharfbuzz/hb/; s/-/_/g; s/[.].*//'`
 
diff --git a/src/hb-aat-layout-common.hh b/src/hb-aat-layout-common.hh
index 57374b0bc..052aad7fc 100644
--- a/src/hb-aat-layout-common.hh
+++ b/src/hb-aat-layout-common.hh
@@ -569,7 +569,8 @@ struct StateTableDriver
 	/* If there's no action and we're just epsilon-transitioning to state 0,
 	 * safe to break. */
 	if (c->is_actionable (this, entry) ||
-	    !(entry->newState == 0 && entry->flags == context_t::DontAdvance))
+	    !(entry->newState == StateTable<EntryData>::STATE_START_OF_TEXT &&
+	      entry->flags == context_t::DontAdvance))
 	  buffer->unsafe_to_break (buffer->idx - 1, buffer->idx + 1);
       }
 
diff --git a/src/hb-aat-layout-morx-table.hh b/src/hb-aat-layout-morx-table.hh
index 5d3b9b14a..a8b287fde 100644
--- a/src/hb-aat-layout-morx-table.hh
+++ b/src/hb-aat-layout-morx-table.hh
@@ -608,16 +608,14 @@ struct InsertionSubtable
       hb_buffer_t *buffer = driver->buffer;
       unsigned int flags = entry->flags;
 
-      if (entry->data.markedInsertIndex != 0xFFFF)
+      if (entry->data.markedInsertIndex != 0xFFFF && mark_set)
       {
-	unsigned int count = (entry->flags & MarkedInsertCount);
+	unsigned int count = (flags & MarkedInsertCount);
 	unsigned int start = entry->data.markedInsertIndex;
 	const GlyphID *glyphs = &insertionAction[start];
 	if (unlikely (!c->sanitizer.check_array (glyphs, count))) return false;
 
-	bool before = entry->flags & MarkedInsertBefore;
-
-	if (unlikely (!mark_set)) return false;
+	bool before = flags & MarkedInsertBefore;
 
 	unsigned int end = buffer->out_len;
 	buffer->move_to (mark);
@@ -635,12 +633,12 @@ struct InsertionSubtable
 
       if (entry->data.currentInsertIndex != 0xFFFF)
       {
-	unsigned int count = (entry->flags & CurrentInsertCount) >> 5;
+	unsigned int count = (flags & CurrentInsertCount) >> 5;
 	unsigned int start = entry->data.currentInsertIndex;
 	const GlyphID *glyphs = &insertionAction[start];
 	if (unlikely (!c->sanitizer.check_array (glyphs, count))) return false;
 
-	bool before = entry->flags & CurrentInsertBefore;
+	bool before = flags & CurrentInsertBefore;
 
 	unsigned int end = buffer->out_len;
 
@@ -652,7 +650,20 @@ struct InsertionSubtable
 	if (!before)
 	  buffer->skip_glyph ();
 
-	buffer->move_to (end);
+	/* Humm. Not sure where to move to.  There's this wording under
+	 * DontAdvance flag:
+	 *
+	 * "If set, don't update the glyph index before going to the new state.
+	 * This does not mean that the glyph pointed to is the same one as
+	 * before. If you've made insertions immediately downstream of the
+	 * current glyph, the next glyph processed would in fact be the first
+	 * one inserted."
+	 *
+	 * This suggests that if DontAdvance is NOT set, we should move to
+	 * end+count.  If it *was*, then move to end, such that newly inserted
+	 * glyphs are now visible.
+	 */
+	buffer->move_to ((flags & DontAdvance) ? end : end + count);
       }
 
       if (flags & SetMark)
@@ -730,8 +741,25 @@ struct ChainSubtable
   friend struct Chain;
 
   inline unsigned int get_size (void) const { return length; }
-  inline unsigned int get_type (void) const { return coverage & 0xFF; }
+  inline unsigned int get_type (void) const { return coverage & SubtableType; }
 
+  enum Coverage
+  {
+    Vertical		= 0x80000000,	/* If set, this subtable will only be applied
+					 * to vertical text. If clear, this subtable
+					 * will only be applied to horizontal text. */
+    Descending		= 0x40000000,	/* If set, this subtable will process glyphs
+					 * in descending order. If clear, it will
+					 * process the glyphs in ascending order. */
+    AllDirections	= 0x20000000,	/* If set, this subtable will be applied to
+					 * both horizontal and vertical text (i.e.
+					 * the state of bit 0x80000000 is ignored). */
+    Logical		= 0x10000000,	/* If set, this subtable will process glyphs
+					 * in logical order (or reverse logical order,
+					 * depending on the value of bit 0x80000000). */
+    Reserved		= 0x0FFFFF00,	/* Reserved, set to zero. */
+    SubtableType	= 0x000000FF,	/* Subtable type; see following table. */
+  };
   enum Type
   {
     Rearrangement	= 0,
@@ -806,14 +834,59 @@ struct Chain
     unsigned int count = subtableCount;
     for (unsigned int i = 0; i < count; i++)
     {
+      bool reverse;
+
       if (!(subtable->subFeatureFlags & flags))
         goto skip;
 
+      if (!(subtable->coverage & ChainSubtable::AllDirections) &&
+	  HB_DIRECTION_IS_VERTICAL (c->buffer->props.direction) !=
+	  bool (subtable->coverage & ChainSubtable::Vertical))
+        goto skip;
+
+      /* Buffer contents is always in logical direction.  Determine if
+       * we need to reverse before applying this subtable.  We reverse
+       * back after if we did reverse indeed.
+       *
+       * Quoting the spac:
+       * """
+       * Bits 28 and 30 of the coverage field control the order in which
+       * glyphs are processed when the subtable is run by the layout engine.
+       * Bit 28 is used to indicate if the glyph processing direction is
+       * the same as logical order or layout order. Bit 30 is used to
+       * indicate whether glyphs are processed forwards or backwards within
+       * that order.
+
+		Bit 30	Bit 28	Interpretation for Horizontal Text
+		0	0	The subtable is processed in layout order
+				(the same order as the glyphs, which is
+				always left-to-right).
+		1	0	The subtable is processed in reverse layout order
+				(the order opposite that of the glyphs, which is
+				always right-to-left).
+		0	1	The subtable is processed in logical order
+				(the same order as the characters, which may be
+				left-to-right or right-to-left).
+		1	1	The subtable is processed in reverse logical order
+				(the order opposite that of the characters, which
+				may be right-to-left or left-to-right).
+       */
+      reverse = subtable->coverage & ChainSubtable::Logical ?
+		bool (subtable->coverage & ChainSubtable::Descending) :
+		bool (subtable->coverage & ChainSubtable::Descending) !=
+		HB_DIRECTION_IS_BACKWARD (c->buffer->props.direction);
+
       if (!c->buffer->message (c->font, "start chain subtable %d", c->lookup_index))
         goto skip;
 
+      if (reverse)
+        c->buffer->reverse ();
+
       subtable->dispatch (c);
 
+      if (reverse)
+        c->buffer->reverse ();
+
       (void) c->buffer->message (c->font, "end chain subtable %d", c->lookup_index);
 
     skip:
diff --git a/src/hb-blob.cc b/src/hb-blob.cc
index a335df308..fca3c910b 100644
--- a/src/hb-blob.cc
+++ b/src/hb-blob.cc
@@ -574,18 +574,45 @@ fail_without_close:
   wchar_t * wchar_file_name = (wchar_t *) malloc (sizeof (wchar_t) * size);
   if (unlikely (wchar_file_name == nullptr)) goto fail_without_close;
   mbstowcs (wchar_file_name, file_name, size);
+#if defined(WINAPI_FAMILY) && (WINAPI_FAMILY==WINAPI_FAMILY_PC_APP || WINAPI_FAMILY==WINAPI_FAMILY_PHONE_APP)
+  {
+    CREATEFILE2_EXTENDED_PARAMETERS ceparams = { 0 };
+    ceparams.dwSize = sizeof(CREATEFILE2_EXTENDED_PARAMETERS);
+    ceparams.dwFileAttributes = FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED & 0xFFFF;
+    ceparams.dwFileFlags = FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED & 0xFFF00000;
+    ceparams.dwSecurityQosFlags = FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED & 0x000F0000;
+    ceparams.lpSecurityAttributes = nullptr;
+    ceparams.hTemplateFile = nullptr;
+    fd = CreateFile2 (wchar_file_name, GENERIC_READ, FILE_SHARE_READ,
+                      OPEN_EXISTING, &ceparams);
+  }
+#else
   fd = CreateFileW (wchar_file_name, GENERIC_READ, FILE_SHARE_READ, nullptr,
 		    OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL|FILE_FLAG_OVERLAPPED,
 		    nullptr);
+#endif
   free (wchar_file_name);
 
   if (unlikely (fd == INVALID_HANDLE_VALUE)) goto fail_without_close;
 
+#if defined(WINAPI_FAMILY) && (WINAPI_FAMILY==WINAPI_FAMILY_PC_APP || WINAPI_FAMILY==WINAPI_FAMILY_PHONE_APP)
+  {
+    LARGE_INTEGER length;
+    GetFileSizeEx (fd, &length);
+    file->length = length.LowPart;
+    file->mapping = CreateFileMappingFromApp (fd, nullptr, PAGE_READONLY, length.QuadPart, nullptr);
+  }
+#else
   file->length = (unsigned long) GetFileSize (fd, nullptr);
   file->mapping = CreateFileMapping (fd, nullptr, PAGE_READONLY, 0, 0, nullptr);
+#endif
   if (unlikely (file->mapping == nullptr)) goto fail;
 
+#if defined(WINAPI_FAMILY) && (WINAPI_FAMILY==WINAPI_FAMILY_PC_APP || WINAPI_FAMILY==WINAPI_FAMILY_PHONE_APP)
+  file->contents = (char *) MapViewOfFileFromApp (file->mapping, FILE_MAP_READ, 0, 0);
+#else
   file->contents = (char *) MapViewOfFile (file->mapping, FILE_MAP_READ, 0, 0, 0);
+#endif
   if (unlikely (file->contents == nullptr)) goto fail;
 
   CloseHandle (fd);
diff --git a/src/hb-buffer.cc b/src/hb-buffer.cc
index 536ab5d53..8fecea721 100644
--- a/src/hb-buffer.cc
+++ b/src/hb-buffer.cc
@@ -1887,6 +1887,10 @@ hb_buffer_t::sort (unsigned int start, unsigned int end, int(*compar)(const hb_g
 
 /**
  * hb_buffer_diff:
+ * @buffer: a buffer.
+ * @reference: other buffer to compare to.
+ * @dottedcircle_glyph: glyph id of U+25CC DOTTED CIRCLE, or (hb_codepont_t) -1.
+ * @position_fuzz: allowed absolute difference in position values.
  *
  * If dottedcircle_glyph is (hb_codepoint_t) -1 then %HB_BUFFER_DIFF_FLAG_DOTTED_CIRCLE_PRESENT
  * and %HB_BUFFER_DIFF_FLAG_NOTDEF_PRESENT are never returned.  This should be used by most
diff --git a/src/hb-buffer.h b/src/hb-buffer.h
index 8a2d3e869..4ed458fbb 100644
--- a/src/hb-buffer.h
+++ b/src/hb-buffer.h
@@ -44,7 +44,6 @@ HB_BEGIN_DECLS
  * hb_glyph_info_t:
  * @codepoint: either a Unicode code point (before shaping) or a glyph index
  *             (after shaping).
- * @mask: 
  * @cluster: the index of the character in the original text that corresponds
  *           to this #hb_glyph_info_t, or whatever the client passes to
  *           hb_buffer_add(). More than one #hb_glyph_info_t can have the same
@@ -59,11 +58,13 @@ HB_BEGIN_DECLS
  *
  * The #hb_glyph_info_t is the structure that holds information about the
  * glyphs and their relation to input text.
- *
  */
-typedef struct hb_glyph_info_t {
+typedef struct hb_glyph_info_t
+{
   hb_codepoint_t codepoint;
-  hb_mask_t      mask; /* Holds hb_glyph_flags_t after hb_shape(), plus other things. */
+  /*< private >*/
+  hb_mask_t      mask;
+  /*< public >*/
   uint32_t       cluster;
 
   /*< private >*/
@@ -92,6 +93,7 @@ typedef struct hb_glyph_info_t {
 typedef enum { /*< flags >*/
   HB_GLYPH_FLAG_UNSAFE_TO_BREAK		= 0x00000001,
 
+  /*< private >*/
   HB_GLYPH_FLAG_DEFINED			= 0x00000001 /* OR of all defined flags */
 } hb_glyph_flags_t;
 
@@ -298,7 +300,15 @@ hb_buffer_set_flags (hb_buffer_t       *buffer,
 HB_EXTERN hb_buffer_flags_t
 hb_buffer_get_flags (hb_buffer_t *buffer);
 
-/*
+/**
+ * hb_buffer_cluster_level_t:
+ * @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES: Return cluster values grouped by graphemes into
+ *   monotone order.
+ * @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS: Return cluster values grouped into monotone order.
+ * @HB_BUFFER_CLUSTER_LEVEL_CHARACTERS: Don't group cluster values.
+ * @HB_BUFFER_CLUSTER_LEVEL_DEFAULT: Default cluster level,
+ *   equal to @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES.
+ *
  * Since: 0.9.42
  */
 typedef enum {
diff --git a/src/hb-coretext.cc b/src/hb-coretext.cc
index a7ba85f83..f921e3a02 100644
--- a/src/hb-coretext.cc
+++ b/src/hb-coretext.cc
@@ -515,12 +515,14 @@ struct range_record_t {
 #define kUpperCaseType				38
 
 /* Table data courtesy of Apple. */
-static const struct feature_mapping_t {
-    FourCharCode otFeatureTag;
+static const struct feature_mapping_t
+{
+    hb_tag_t otFeatureTag;
     uint16_t aatFeatureType;
     uint16_t selectorToEnable;
     uint16_t selectorToDisable;
-} feature_mappings[] = {
+} feature_mappings[] =
+{
     { 'c2pc',   kUpperCaseType,             kUpperCasePetiteCapsSelector,           kDefaultUpperCaseSelector },
     { 'c2sc',   kUpperCaseType,             kUpperCaseSmallCapsSelector,            kDefaultUpperCaseSelector },
     { 'calt',   kContextualAlternatesType,  kContextualAlternatesOnSelector,        kContextualAlternatesOffSelector },
@@ -601,7 +603,7 @@ static const struct feature_mapping_t {
 static int
 _hb_feature_mapping_cmp (const void *key_, const void *entry_)
 {
-  unsigned int key = * (unsigned int *) key_;
+  hb_tag_t key = * (unsigned int *) key_;
   const feature_mapping_t * entry = (const feature_mapping_t *) entry_;
   return key < entry->otFeatureTag ? -1 :
 	 key > entry->otFeatureTag ? 1 :
diff --git a/src/hb-face.cc b/src/hb-face.cc
index 922fd8fd0..19eea4d34 100644
--- a/src/hb-face.cc
+++ b/src/hb-face.cc
@@ -36,12 +36,12 @@
 
 
 /**
- * hb_face_count: Get number of faces on the blob
- * @blob:
+ * hb_face_count:
+ * @blob: a blob.
  *
+ * Get number of faces in a blob.
  *
- *
- * Return value: Number of faces on the blob
+ * Return value: Number of faces in @blob
  *
  * Since: 1.7.7
  **/
@@ -488,6 +488,9 @@ hb_face_get_glyph_count (const hb_face_t *face)
 /**
  * hb_face_get_table_tags:
  * @face: a face.
+ * @start_offset: index of first tag to return.
+ * @table_count: input length of @table_tags array, output number of items written.
+ * @table_tags: array to write tags into.
  *
  * Retrieves table tags for a face, if possible.
  *
diff --git a/src/hb-font.cc b/src/hb-font.cc
index bc831dd53..9dcf6c123 100644
--- a/src/hb-font.cc
+++ b/src/hb-font.cc
@@ -1703,9 +1703,11 @@ hb_font_get_ppem (hb_font_t *font,
 /**
  * hb_font_set_ptem:
  * @font: a font.
- * @ptem: 
+ * @ptem: font size in points.
  *
- * Sets "point size" of the font.
+ * Sets "point size" of the font.  Set to 0 to unset.
+ *
+ * There are 72 points in an inch.
  *
  * Since: 1.6.0
  **/
@@ -1931,9 +1933,9 @@ hb_font_get_variation_glyph_trampoline (hb_font_t *font,
 /**
  * hb_font_funcs_set_glyph_func:
  * @ffuncs: font functions.
- * @func: (closure user_data) (destroy destroy) (scope notified):
- * @user_data:
- * @destroy:
+ * @func: (closure user_data) (destroy destroy) (scope notified): callback function.
+ * @user_data: data to pass to @func.
+ * @destroy: function to call when @user_data is not needed anymore.
  *
  * Deprecated.  Use hb_font_funcs_set_nominal_glyph_func() and
  * hb_font_funcs_set_variation_glyph_func() instead.
diff --git a/src/hb-ot-layout-gsubgpos.hh b/src/hb-ot-layout-gsubgpos.hh
index ff9783edc..031b39b9b 100644
--- a/src/hb-ot-layout-gsubgpos.hh
+++ b/src/hb-ot-layout-gsubgpos.hh
@@ -344,10 +344,10 @@ struct hb_ot_apply_context_t :
       match_glyph_data = nullptr;
       matcher.set_match_func (nullptr, nullptr);
       matcher.set_lookup_props (c->lookup_props);
-      /* Ignore ZWNJ if we are matching GSUB context, or matching GPOS. */
+      /* Ignore ZWNJ if we are matching GPOS, or matching GSUB context and asked to. */
       matcher.set_ignore_zwnj (c->table_index == 1 || (context_match && c->auto_zwnj));
-      /* Ignore ZWJ if we are matching GSUB context, or matching GPOS, or if asked to. */
-      matcher.set_ignore_zwj  (c->table_index == 1 || (context_match || c->auto_zwj));
+      /* Ignore ZWJ if we are matching context, or asked to. */
+      matcher.set_ignore_zwj  (context_match || c->auto_zwj);
       matcher.set_mask (context_match ? -1 : c->lookup_mask);
     }
     inline void set_lookup_props (unsigned int lookup_props)
@@ -508,19 +508,20 @@ struct hb_ot_apply_context_t :
 			random (false),
 			random_state (1) {}
 
-  inline void set_lookup_mask (hb_mask_t mask) { lookup_mask = mask; }
-  inline void set_auto_zwj (bool auto_zwj_) { auto_zwj = auto_zwj_; }
-  inline void set_auto_zwnj (bool auto_zwnj_) { auto_zwnj = auto_zwnj_; }
-  inline void set_random (bool random_) { random = random_; }
-  inline void set_recurse_func (recurse_func_t func) { recurse_func = func; }
-  inline void set_lookup_index (unsigned int lookup_index_) { lookup_index = lookup_index_; }
-  inline void set_lookup_props (unsigned int lookup_props_)
+  inline void reinit_iters (void)
   {
-    lookup_props = lookup_props_;
     iter_input.init (this, false);
     iter_context.init (this, true);
   }
 
+  inline void set_lookup_mask (hb_mask_t mask) { lookup_mask = mask; }
+  inline void set_auto_zwj (bool auto_zwj_) { auto_zwj = auto_zwj_; reinit_iters (); }
+  inline void set_auto_zwnj (bool auto_zwnj_) { auto_zwnj = auto_zwnj_; reinit_iters (); }
+  inline void set_random (bool random_) { random = random_; }
+  inline void set_recurse_func (recurse_func_t func) { recurse_func = func; }
+  inline void set_lookup_index (unsigned int lookup_index_) { lookup_index = lookup_index_; }
+  inline void set_lookup_props (unsigned int lookup_props_) { lookup_props = lookup_props_; reinit_iters (); }
+
   inline uint32_t random_number (void)
   {
     /* http://www.cplusplus.com/reference/random/minstd_rand/ */
diff --git a/src/hb-ot-post-table.hh b/src/hb-ot-post-table.hh
index 5f27fd504..f81de37d5 100644
--- a/src/hb-ot-post-table.hh
+++ b/src/hb-ot-post-table.hh
@@ -131,6 +131,7 @@ struct post
     {
       index_to_offset.fini ();
       free (gids_sorted_by_name.get ());
+      hb_blob_destroy (blob);
     }
 
     inline bool get_glyph_name (hb_codepoint_t glyph,
diff --git a/src/hb-ot-shape-complex-indic.cc b/src/hb-ot-shape-complex-indic.cc
index 369078cb2..c1aa1d0fe 100644
--- a/src/hb-ot-shape-complex-indic.cc
+++ b/src/hb-ot-shape-complex-indic.cc
@@ -95,7 +95,8 @@ static const indic_config_t indic_configs[] =
  * Indic shaper.
  */
 
-struct feature_list_t {
+struct feature_list_t
+{
   hb_tag_t tag;
   hb_ot_map_feature_flags_t flags;
 };
@@ -130,7 +131,10 @@ indic_features[] =
   {HB_TAG('b','l','w','s'), F_GLOBAL},
   {HB_TAG('p','s','t','s'), F_GLOBAL},
   {HB_TAG('h','a','l','n'), F_GLOBAL},
-  /* Positioning features, though we don't care about the types. */
+  /*
+   * Positioning features.
+   * We don't care about the types.
+   */
   {HB_TAG('d','i','s','t'), F_GLOBAL},
   {HB_TAG('a','b','v','m'), F_GLOBAL},
   {HB_TAG('b','l','w','m'), F_GLOBAL},
@@ -158,12 +162,14 @@ enum {
   _BLWS,
   _PSTS,
   _HALN,
+
   _DIST,
   _ABVM,
   _BLWM,
 
   INDIC_NUM_FEATURES,
-  INDIC_BASIC_FEATURES = INIT /* Don't forget to update this! */
+  INDIC_BASIC_FEATURES = INIT, /* Don't forget to update this! */
+  INDIC_SUBST_FEATURES = _DIST /* Don't forget to update this! */
 };
 
 static void
@@ -199,14 +205,19 @@ collect_features_indic (hb_ot_shape_planner_t *plan)
 
   unsigned int i = 0;
   map->add_gsub_pause (initial_reordering);
+
   for (; i < INDIC_BASIC_FEATURES; i++) {
     map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ);
     map->add_gsub_pause (nullptr);
   }
+
   map->add_gsub_pause (final_reordering);
-  for (; i < INDIC_NUM_FEATURES; i++) {
+
+  for (; i < INDIC_SUBST_FEATURES; i++)
     map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ);
-  }
+
+  for (; i < INDIC_NUM_FEATURES; i++)
+    map->add_feature (indic_features[i].tag, 1, indic_features[i].flags);
 
   map->add_global_bool_feature (HB_TAG('c','a','l','t'));
   map->add_global_bool_feature (HB_TAG('c','l','i','g'));
diff --git a/src/hb-ot-shape-complex-khmer.cc b/src/hb-ot-shape-complex-khmer.cc
index 0b5b50a97..7a88aaa25 100644
--- a/src/hb-ot-shape-complex-khmer.cc
+++ b/src/hb-ot-shape-complex-khmer.cc
@@ -32,7 +32,8 @@
  * Khmer shaper.
  */
 
-struct feature_list_t {
+struct feature_list_t
+{
   hb_tag_t tag;
   hb_ot_map_feature_flags_t flags;
 };
@@ -57,7 +58,10 @@ khmer_features[] =
   {HB_TAG('a','b','v','s'), F_GLOBAL},
   {HB_TAG('b','l','w','s'), F_GLOBAL},
   {HB_TAG('p','s','t','s'), F_GLOBAL},
-  /* Positioning features, though we don't care about the types. */
+  /*
+   * Positioning features.
+   * We don't care about the types.
+   */
   {HB_TAG('d','i','s','t'), F_GLOBAL},
   {HB_TAG('a','b','v','m'), F_GLOBAL},
   {HB_TAG('b','l','w','m'), F_GLOBAL},
@@ -77,12 +81,14 @@ enum {
   _ABVS,
   _BLWS,
   _PSTS,
+
   _DIST,
   _ABVM,
   _BLWM,
 
   KHMER_NUM_FEATURES,
-  KHMER_BASIC_FEATURES = _PRES /* Don't forget to update this! */
+  KHMER_BASIC_FEATURES = _PRES, /* Don't forget to update this! */
+  KHMER_SUBST_FEATURES = _DIST, /* Don't forget to update this! */
 };
 
 static void
@@ -121,15 +127,16 @@ collect_features_khmer (hb_ot_shape_planner_t *plan)
   map->add_global_bool_feature (HB_TAG('c','c','m','p'));
 
   unsigned int i = 0;
-  for (; i < KHMER_BASIC_FEATURES; i++) {
+  for (; i < KHMER_BASIC_FEATURES; i++)
     map->add_feature (khmer_features[i].tag, 1, khmer_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ);
-  }
 
   map->add_gsub_pause (clear_syllables);
 
-  for (; i < KHMER_NUM_FEATURES; i++) {
+  for (; i < KHMER_SUBST_FEATURES; i++)
     map->add_feature (khmer_features[i].tag, 1, khmer_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ);
-  }
+
+  for (; i < KHMER_NUM_FEATURES; i++)
+    map->add_feature (khmer_features[i].tag, 1, khmer_features[i].flags);
 
   map->add_global_bool_feature (HB_TAG('c','a','l','t'));
   map->add_global_bool_feature (HB_TAG('c','l','i','g'));
diff --git a/src/hb-ot-shape-complex-myanmar.cc b/src/hb-ot-shape-complex-myanmar.cc
index 8466f8129..8069e3d99 100644
--- a/src/hb-ot-shape-complex-myanmar.cc
+++ b/src/hb-ot-shape-complex-myanmar.cc
@@ -54,7 +54,14 @@ other_features[] =
   HB_TAG('a','b','v','s'),
   HB_TAG('b','l','w','s'),
   HB_TAG('p','s','t','s'),
-  /* Positioning features, though we don't care about the types. */
+};
+static const hb_tag_t
+positioning_features[] =
+{
+  /*
+   * Positioning features.
+   * We don't care about the types.
+   */
   HB_TAG('d','i','s','t'),
   /* Pre-release version of Windows 8 Myanmar font had abvm,blwm
    * features.  The released Windows 8 version of the font (as well
@@ -96,14 +103,20 @@ collect_features_myanmar (hb_ot_shape_planner_t *plan)
 
 
   map->add_gsub_pause (initial_reordering);
+
   for (unsigned int i = 0; i < ARRAY_LENGTH (basic_features); i++)
   {
     map->add_feature (basic_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
     map->add_gsub_pause (nullptr);
   }
+
   map->add_gsub_pause (final_reordering);
+
   for (unsigned int i = 0; i < ARRAY_LENGTH (other_features); i++)
     map->add_feature (other_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
+
+  for (unsigned int i = 0; i < ARRAY_LENGTH (positioning_features); i++)
+    map->add_feature (positioning_features[i], 1, F_GLOBAL);
 }
 
 static void
diff --git a/src/hb-ot-shape-complex-use.cc b/src/hb-ot-shape-complex-use.cc
index 676b15b6e..62aef7e6f 100644
--- a/src/hb-ot-shape-complex-use.cc
+++ b/src/hb-ot-shape-complex-use.cc
@@ -86,7 +86,14 @@ other_features[] =
   HB_TAG('h','a','l','n'),
   HB_TAG('p','r','e','s'),
   HB_TAG('p','s','t','s'),
-  /* Positioning features, though we don't care about the types. */
+};
+static const hb_tag_t
+positioning_features[] =
+{
+  /*
+   * Positioning features.
+   * We don't care about the types.
+   */
   HB_TAG('d','i','s','t'),
   HB_TAG('a','b','v','m'),
   HB_TAG('b','l','w','m'),
@@ -146,9 +153,13 @@ collect_features_use (hb_ot_shape_planner_t *plan)
     map->add_feature (arabic_features[i], 1, F_NONE);
   map->add_gsub_pause (nullptr);
 
-  /* "Standard typographic presentation" and "Positional feature application" */
+  /* "Standard typographic presentation" */
   for (unsigned int i = 0; i < ARRAY_LENGTH (other_features); i++)
     map->add_feature (other_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
+
+  /* "Positional feature application" */
+  for (unsigned int i = 0; i < ARRAY_LENGTH (positioning_features); i++)
+    map->add_feature (positioning_features[i], 1, F_GLOBAL);
 }
 
 struct use_shape_plan_t
diff --git a/src/hb-ot-shape-normalize.cc b/src/hb-ot-shape-normalize.cc
index fd0b63aec..2f0cba184 100644
--- a/src/hb-ot-shape-normalize.cc
+++ b/src/hb-ot-shape-normalize.cc
@@ -294,6 +294,16 @@ _hb_ot_shape_normalize (const hb_ot_shape_plan_t *plan,
   _hb_buffer_assert_unicode_vars (buffer);
 
   hb_ot_shape_normalization_mode_t mode = plan->shaper->normalization_preference;
+  if (mode == HB_OT_SHAPE_NORMALIZATION_MODE_AUTO)
+  {
+    if (plan->has_mark)
+      // https://github.com/harfbuzz/harfbuzz/issues/653#issuecomment-423905920
+      //mode = HB_OT_SHAPE_NORMALIZATION_MODE_DECOMPOSED;
+      mode = HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS;
+    else
+      mode = HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS;
+  }
+
   const hb_ot_shape_normalize_context_t c = {
     plan,
     buffer,
@@ -358,65 +368,6 @@ _hb_ot_shape_normalize (const hb_ot_shape_plan_t *plan,
 
     i = end;
   }
-
-
-  if (mode == HB_OT_SHAPE_NORMALIZATION_MODE_NONE ||
-      mode == HB_OT_SHAPE_NORMALIZATION_MODE_DECOMPOSED)
-    return;
-
-  /* Third round, recompose */
-
-  /* As noted in the comment earlier, we don't try to combine
-   * ccc=0 chars with their previous Starter. */
-
-  buffer->clear_output ();
-  count = buffer->len;
-  unsigned int starter = 0;
-  buffer->next_glyph ();
-  while (buffer->idx < count && buffer->successful)
-  {
-    hb_codepoint_t composed, glyph;
-    if (/* We don't try to compose a non-mark character with it's preceding starter.
-	 * This is both an optimization to avoid trying to compose every two neighboring
-	 * glyphs in most scripts AND a desired feature for Hangul.  Apparently Hangul
-	 * fonts are not designed to mix-and-match pre-composed syllables and Jamo. */
-	HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&buffer->cur())))
-    {
-      if (/* If there's anything between the starter and this char, they should have CCC
-	   * smaller than this character's. */
-	  (starter == buffer->out_len - 1 ||
-	   info_cc (buffer->prev()) < info_cc (buffer->cur())) &&
-	  /* And compose. */
-	  c.compose (&c,
-		     buffer->out_info[starter].codepoint,
-		     buffer->cur().codepoint,
-		     &composed) &&
-	  /* And the font has glyph for the composite. */
-	  font->get_nominal_glyph (composed, &glyph))
-      {
-	/* Composes. */
-	buffer->next_glyph (); /* Copy to out-buffer. */
-	if (unlikely (!buffer->successful))
-	  return;
-	buffer->merge_out_clusters (starter, buffer->out_len);
-	buffer->out_len--; /* Remove the second composable. */
-	/* Modify starter and carry on. */
-	buffer->out_info[starter].codepoint = composed;
-	buffer->out_info[starter].glyph_index() = glyph;
-	_hb_glyph_info_set_unicode_props (&buffer->out_info[starter], buffer);
-
-	continue;
-      }
-    }
-
-    /* Blocked, or doesn't compose. */
-    buffer->next_glyph ();
-
-    if (info_cc (buffer->prev()) == 0)
-      starter = buffer->out_len - 1;
-  }
-  buffer->swap_buffers ();
-
   if (buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_HAS_CGJ)
   {
     /* For all CGJ, check if it prevented any reordering at all.
@@ -430,4 +381,62 @@ _hb_ot_shape_normalize (const hb_ot_shape_plan_t *plan,
 	_hb_glyph_info_unhide (&buffer->info[i]);
       }
   }
+
+
+  /* Third round, recompose */
+
+  if (mode == HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS ||
+      mode == HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT)
+  {
+    /* As noted in the comment earlier, we don't try to combine
+     * ccc=0 chars with their previous Starter. */
+
+    buffer->clear_output ();
+    count = buffer->len;
+    unsigned int starter = 0;
+    buffer->next_glyph ();
+    while (buffer->idx < count && buffer->successful)
+    {
+      hb_codepoint_t composed, glyph;
+      if (/* We don't try to compose a non-mark character with it's preceding starter.
+	   * This is both an optimization to avoid trying to compose every two neighboring
+	   * glyphs in most scripts AND a desired feature for Hangul.  Apparently Hangul
+	   * fonts are not designed to mix-and-match pre-composed syllables and Jamo. */
+	  HB_UNICODE_GENERAL_CATEGORY_IS_MARK (_hb_glyph_info_get_general_category (&buffer->cur())))
+      {
+	if (/* If there's anything between the starter and this char, they should have CCC
+	     * smaller than this character's. */
+	    (starter == buffer->out_len - 1 ||
+	     info_cc (buffer->prev()) < info_cc (buffer->cur())) &&
+	    /* And compose. */
+	    c.compose (&c,
+		       buffer->out_info[starter].codepoint,
+		       buffer->cur().codepoint,
+		       &composed) &&
+	    /* And the font has glyph for the composite. */
+	    font->get_nominal_glyph (composed, &glyph))
+	{
+	  /* Composes. */
+	  buffer->next_glyph (); /* Copy to out-buffer. */
+	  if (unlikely (!buffer->successful))
+	    return;
+	  buffer->merge_out_clusters (starter, buffer->out_len);
+	  buffer->out_len--; /* Remove the second composable. */
+	  /* Modify starter and carry on. */
+	  buffer->out_info[starter].codepoint = composed;
+	  buffer->out_info[starter].glyph_index() = glyph;
+	  _hb_glyph_info_set_unicode_props (&buffer->out_info[starter], buffer);
+
+	  continue;
+	}
+      }
+
+      /* Blocked, or doesn't compose. */
+      buffer->next_glyph ();
+
+      if (info_cc (buffer->prev()) == 0)
+	starter = buffer->out_len - 1;
+    }
+    buffer->swap_buffers ();
+  }
 }
diff --git a/src/hb-ot-shape-normalize.hh b/src/hb-ot-shape-normalize.hh
index 4aea640b1..80755f775 100644
--- a/src/hb-ot-shape-normalize.hh
+++ b/src/hb-ot-shape-normalize.hh
@@ -38,10 +38,11 @@ struct hb_ot_shape_plan_t;
 enum hb_ot_shape_normalization_mode_t {
   HB_OT_SHAPE_NORMALIZATION_MODE_NONE,
   HB_OT_SHAPE_NORMALIZATION_MODE_DECOMPOSED,
-  HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS, /* never composes base-to-base */
-  HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT, /* always fully decomposes and then recompose back */
+  HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS, /* Never composes base-to-base */
+  HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT, /* Always fully decomposes and then recompose back */
 
-  HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT = HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS
+  HB_OT_SHAPE_NORMALIZATION_MODE_AUTO, /* Choose decomposed if GPOS mark feature available, compose otherwise. */
+  HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT = HB_OT_SHAPE_NORMALIZATION_MODE_AUTO
 };
 
 HB_INTERNAL void _hb_ot_shape_normalize (const hb_ot_shape_plan_t *shaper,
diff --git a/src/hb.hh b/src/hb.hh
index 557ae6b35..631592def 100644
--- a/src/hb.hh
+++ b/src/hb.hh
@@ -237,7 +237,9 @@ struct _hb_alignof
 #    undef _WIN32_WINNT
 #  endif
 #  ifndef _WIN32_WINNT
-#    define _WIN32_WINNT 0x0600
+#    if !defined(WINAPI_FAMILY) || !(WINAPI_FAMILY==WINAPI_FAMILY_PC_APP || WINAPI_FAMILY==WINAPI_FAMILY_PHONE_APP)
+#      define _WIN32_WINNT 0x0600
+#    endif
 #  endif
 #  ifndef WIN32_LEAN_AND_MEAN
 #    define WIN32_LEAN_AND_MEAN 1
diff --git a/test/api/hb-subset-test.h b/test/api/hb-subset-test.h
index afd553a0d..0318fa7bb 100644
--- a/test/api/hb-subset-test.h
+++ b/test/api/hb-subset-test.h
@@ -51,12 +51,18 @@ static inline hb_face_t *
 hb_subset_test_open_font (const char *font_path)
 {
 #if GLIB_CHECK_VERSION(2,37,2)
-  char* path = g_test_build_filename(G_TEST_DIST, font_path, NULL);
+  char* path = g_test_build_filename (G_TEST_DIST, font_path, NULL);
 #else
-  char* path = g_strdup(font_path);
+  char* path = g_strdup (font_path);
 #endif
 
-  return hb_face_create (hb_blob_create_from_file (path), 0);
+  hb_blob_t* blob = hb_blob_create_from_file (path);
+  hb_face_t* face = hb_face_create (blob, 0);
+  hb_blob_destroy (blob);
+
+  g_free (path);
+
+  return face;
 }
 
 static inline hb_subset_input_t *
diff --git a/test/api/test-font.c b/test/api/test-font.c
index 527dfcdc1..4a2393ec6 100644
--- a/test/api/test-font.c
+++ b/test/api/test-font.c
@@ -361,6 +361,7 @@ test_fontfuncs_subclassing (void)
 
 
   hb_font_destroy (font3);
+  hb_font_destroy (font2);
 }
 
 
diff --git a/test/api/test-ot-math.c b/test/api/test-ot-math.c
index d071c8895..7f500157e 100644
--- a/test/api/test-ot-math.c
+++ b/test/api/test-ot-math.c
@@ -100,10 +100,14 @@ test_has_data (void)
   hb_face = hb_face_get_empty ();
   hb_font = hb_font_create (hb_face);
   g_assert(!hb_ot_math_has_data (hb_face)); // MATH table not available
+  hb_font_destroy (hb_font);
+  hb_face_destroy (hb_face);
 
   hb_font = hb_font_get_empty ();
   hb_face = hb_font_get_face (hb_font);
   g_assert(!hb_ot_math_has_data (hb_face)); // MATH table not available
+  hb_font_destroy (hb_font);
+  hb_face_destroy (hb_face);
 
   cleanupFreeType();
 }
diff --git a/test/api/test-set.c b/test/api/test-set.c
index 338a610c9..eb2f22ece 100644
--- a/test/api/test-set.c
+++ b/test/api/test-set.c
@@ -262,6 +262,7 @@ test_set_algebra (void)
 
   hb_set_destroy (s);
   hb_set_destroy (o);
+  hb_set_destroy (o2);
 }
 
 static void
diff --git a/test/shaping/run-tests.py b/test/shaping/run-tests.py
index 73b61c21a..915536b97 100755
--- a/test/shaping/run-tests.py
+++ b/test/shaping/run-tests.py
@@ -9,7 +9,7 @@ def cmd(command):
 	p = subprocess.Popen (
 		command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
 	p.wait ()
-	print (p.stderr.read (), end="") # file=sys.stderr
+	print (p.stderr.read ().decode ("utf-8").strip ()) # file=sys.stderr
 	return p.stdout.read ().decode ("utf-8").strip (), p.returncode