Fix hash tables not being purified correctly.

* src/alloc.c
(purecopy_hash_table) New function, makes a copy of the given hash
table in pure storage.
Add new struct `pinned_object' and `pinned_objects' linked list for
pinning objects.
(Fpurecopy) Allow purifying hash tables
(purecopy) Pin hash tables that are either weak or not declared with
`:purecopy t`, use purecopy_hash_table otherwise.
(marked_pinned_objects) New function, marks all objects in pinned_objects.
(garbage_collect_1) Use it. Mark all pinned objects before sweeping.
* src/lisp.h Add new field `pure' to struct `Lisp_Hash_Table'.
* src/fns.c: Add `purecopy' parameter to hash tables.
(Fmake_hash_table): Check for a `:purecopy PURECOPY' argument, pass it
to make_hash_table.
(make_hash_table): Add `pure' parameter, set h->pure to it.
(Fclrhash, Fremhash, Fputhash): Enforce that the table is impure with
CHECK_IMPURE.
* src/lread.c: (read1) Parse for `purecopy' parameter while reading
  hash tables.
* src/print.c: (print_object) add the `purecopy' parameter while
  printing hash tables.
* src/category.c, src/emacs-module.c, src/image.c, src/profiler.c,
  src/xterm.c: Use new (make_hash_table).

1 files changed, 7 insertions, 1 deletions

diff --git a/src/lread.c b/src/lread.c
index ea2a1d1d858..17806922a8c 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -2599,7 +2599,7 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
 	      Lisp_Object val = Qnil;
 	      /* The size is 2 * number of allowed keywords to
 		 make-hash-table.  */
-	      Lisp_Object params[10];
+	      Lisp_Object params[12];
 	      Lisp_Object ht;
 	      Lisp_Object key = Qnil;
 	      int param_count = 0;
@@ -2636,6 +2636,11 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
 	      if (!NILP (params[param_count + 1]))
 		param_count += 2;
 
+              params[param_count] = QCpurecopy;
+              params[param_count + 1] = Fplist_get (tmp, Qpurecopy);
+              if (!NILP (params[param_count + 1]))
+                param_count += 2;
+
 	      /* This is the hash table data.  */
 	      data = Fplist_get (tmp, Qdata);
 
@@ -4849,6 +4854,7 @@ that are loaded before your customizations are read!  */);
   DEFSYM (Qdata, "data");
   DEFSYM (Qtest, "test");
   DEFSYM (Qsize, "size");
+  DEFSYM (Qpurecopy, "purecopy");
   DEFSYM (Qweakness, "weakness");
   DEFSYM (Qrehash_size, "rehash-size");
   DEFSYM (Qrehash_threshold, "rehash-threshold");