Add support for finalizers

+2015-03-02  Daniel Colascione  <dancol@dancol.org>
+
+	* NEWS: Mention finalizers.
+
 2015-02-09  Gareth Rees  <gdr@garethrees.org>  (tiny change)

 	* NEWS.24: Fix typo (bug#19820)
diff --git a/src/ChangeLog b/src/ChangeLog
index 4aa64c1..2f04d0b 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,21 @@
+2015-03-02  Daniel Colascione  <dancol@dancol.org>
+
+	* print.c (print_object): Print finalizers.
+
+	* alloc.c:
+	(finalizers, doomed_finalizers): New variables.
+	(init_finalizer_list, finalizer_insert, unchain_finalizer)
+	(mark_finalizer_list, queue_doomed_finalizers)
+	(run_finalizer_handler, run_finalizer_function, run_finalizers):
+	New functions.
+	(garbage_collect_1, mark_object, sweep_misc)
+	(init_alloc_once, syms_of_alloc): Support finalizers.
+	(gc-precise-p): New Lisp variable.
+
+	* lisp.h (Lisp_Misc_Type): New value Lisp_Misc_Finalizer.
+	(FINALIZERP, XFINALIZER): New functions.
+	(Lisp_Finalizer): New structure.
+
 2015-02-28  Paul Eggert  <eggert@cs.ucla.edu>

 	* character.c (alphabeticp, decimalnump): Avoid undefined behavior
diff --git a/test/ChangeLog b/test/ChangeLog
index cf1b2c1..684e98f 100644
--- a/test/ChangeLog
+++ b/test/ChangeLog
@@ -1,3 +1,9 @@
+2015-03-02  Daniel Colascione  <dancol@dancol.org>
+
+	* automated/finalizer-tests.el (finalizer-basic)
+	(finalizer-circular-reference, finalizer-cross-reference)
+	(finalizer-error): New tests.
+
 2015-03-01  Michael Albinus  <michael.albinus@gmx.de>

 	* automated/vc-tests.el (vc-test--create-repo): Add check for

1 files changed, 33 insertions, 0 deletions

diff --git a/src/lisp.h b/src/lisp.h
index fb436776121..37f3b28242b 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -488,6 +488,7 @@ enum Lisp_Misc_Type
     Lisp_Misc_Marker,
     Lisp_Misc_Overlay,
     Lisp_Misc_Save_Value,
+    Lisp_Misc_Finalizer,
     /* Currently floats are not a misc type,
        but let's define this in case we want to change that.  */
     Lisp_Misc_Float,
@@ -600,6 +601,7 @@ INLINE bool OVERLAYP (Lisp_Object);
 INLINE bool PROCESSP (Lisp_Object);
 INLINE bool PSEUDOVECTORP (Lisp_Object, int);
 INLINE bool SAVE_VALUEP (Lisp_Object);
+INLINE bool FINALIZERP (Lisp_Object);
 INLINE void set_sub_char_table_contents (Lisp_Object, ptrdiff_t,
                                               Lisp_Object);
 INLINE bool STRINGP (Lisp_Object);
@@ -610,6 +612,7 @@ INLINE bool (VECTORLIKEP) (Lisp_Object);
 INLINE bool WINDOWP (Lisp_Object);
 INLINE bool TERMINALP (Lisp_Object);
 INLINE struct Lisp_Save_Value *XSAVE_VALUE (Lisp_Object);
+INLINE struct Lisp_Finalizer *XFINALIZER (Lisp_Object);
 INLINE struct Lisp_Symbol *(XSYMBOL) (Lisp_Object);
 INLINE void *(XUNTAG) (Lisp_Object, int);
 
@@ -2183,6 +2186,21 @@ XSAVE_OBJECT (Lisp_Object obj, int n)
   return XSAVE_VALUE (obj)->data[n].object;
 }
 
+/* A finalizer sentinel.  We run FUNCTION when this value becomes
+   unreachable.  We treat these values specially in the GC to ensure
+   that we still run the finalizer even if FUNCTION contains a
+   reference to the finalizer; i.e., we run a finalizer's function
+   when FUNCTION is reachable _only_ through finalizers.  */
+struct Lisp_Finalizer
+  {
+    struct Lisp_Misc_Any base;
+    /* Circular list of all active weak references */
+    struct Lisp_Finalizer *prev;
+    struct Lisp_Finalizer *next;
+     /* Called when this object becomes unreachable */
+    Lisp_Object function;
+  };
+
 /* A miscellaneous object, when it's on the free list.  */
 struct Lisp_Free
   {
@@ -2202,6 +2220,7 @@ union Lisp_Misc
     struct Lisp_Marker u_marker;
     struct Lisp_Overlay u_overlay;
     struct Lisp_Save_Value u_save_value;
+    struct Lisp_Finalizer u_finalizer;
   };
 
 INLINE union Lisp_Misc *
@@ -2243,6 +2262,14 @@ XSAVE_VALUE (Lisp_Object a)
   eassert (SAVE_VALUEP (a));
   return & XMISC (a)->u_save_value;
 }
+
+INLINE struct Lisp_Finalizer *
+XFINALIZER (Lisp_Object a)
+{
+  eassert (FINALIZERP (a));
+  return & XMISC (a)->u_finalizer;
+}
+
 
 /* Forwarding pointer to an int variable.
    This is allowed only in the value cell of a symbol,
@@ -2490,6 +2517,12 @@ SAVE_VALUEP (Lisp_Object x)
 }
 
 INLINE bool
+FINALIZERP (Lisp_Object x)
+{
+  return MISCP (x) && XMISCTYPE (x) == Lisp_Misc_Finalizer;
+}
+
+INLINE bool
 AUTOLOADP (Lisp_Object x)
 {
   return CONSP (x) && EQ (Qautoload, XCAR (x));