From dc53f026909e5373e5c864429897d1dc0780cd6c Mon Sep 17 00:00:00 2001
From: Jim Blandy <jimb@red-bean.com>
Date: Thu, 23 Jul 1998 04:47:56 +0000
Subject: [PATCH] Simplify smob and port marking; set the mark bit in the
 generic marking code, and make marker routines only responsible for turning
 up outgoing pointers. * gc.c (scm_gc_mark): Set the mark bit on ports and
 smobs here, before calling the marking function.  Don't call the marking
 function if it's zero. * markers.c (scm_mark0): Just return #f.  This
 function isn't necessary at all now, but it's harmless to call it.  We'll
 leave it in so other folks' code doesn't croak at link time. (scm_markcdr):
 Don't call SCM_SETGC8MARK. * async.c (mark_async): Don't call SCM_SETGC8MARK.
 * dynl.c (mark_dynl_obj): Same. * root.c (mark_root): Same. * srcprop.c
 (marksrcprops): Same. * unif.c (markra): Same. * variable.c (scm_markvar):
 Same. * ports.c (scm_markstream): Same. (void_port_ptob): Specify zero for
 our marking function. * debug.c (debugobjsmob): Same. * dynwind.c
 (guardsmob): Same. * filesys.c (dir_smob): Same. * fluids.c (fluid_smob):
 Same. * fports.c (scm_fptob, scm_pipob): Same. * mallocs.c (mallocsmob):
 Same. * regex-posix.c (regex_t_smob): Same. * smob.c (freecell, flob, bigob):
 Same. * threads.c (thread_smob, mutex_smob, condvar_smob): Same. * throw.c
 (jbsmob, lazy_catch_funs): Same.

---
 libguile/async.c       |  3 ---
 libguile/debug.c       |  2 +-
 libguile/dynl.c        |  1 -
 libguile/dynwind.c     |  2 +-
 libguile/filesys.c     |  2 +-
 libguile/fluids.c      |  2 +-
 libguile/fports.c      |  4 ++--
 libguile/gc.c          | 24 +++++++++++++++++-------
 libguile/mallocs.c     |  2 +-
 libguile/markers.c     | 14 ++++++++++----
 libguile/ports.c       |  5 +----
 libguile/regex-posix.c |  2 +-
 libguile/root.c        |  2 +-
 libguile/smob.c        |  6 +++---
 libguile/srcprop.c     |  1 -
 libguile/threads.c     |  6 +++---
 libguile/throw.c       |  4 ++--
 libguile/unif.c        |  3 ---
 libguile/variable.c    |  3 ---
 19 files changed, 45 insertions(+), 43 deletions(-)

diff --git a/libguile/async.c b/libguile/async.c
index de7f00f1a..6dd36a061 100644
--- a/libguile/async.c
+++ b/libguile/async.c
@@ -285,9 +285,6 @@ mark_async (obj)
      SCM obj;
 {
   struct scm_async * it;
-  if (SCM_GC8MARKP (obj))
-    return SCM_BOOL_F;
-  SCM_SETGC8MARK (obj);
   it = SCM_ASYNC (obj);
   return it->thunk;
 }
diff --git a/libguile/debug.c b/libguile/debug.c
index 9ec243d61..68ba4f65d 100644
--- a/libguile/debug.c
+++ b/libguile/debug.c
@@ -562,7 +562,7 @@ prindebugobj (obj, port, pstate)
 }
 
 static scm_smobfuns debugobjsmob =
-{scm_mark0, scm_free0, prindebugobj, 0};
+{0, scm_free0, prindebugobj, 0};
 
 SCM_PROC (s_debug_object_p, "debug-object?", 1, 0, 0, scm_debug_object_p);
 
diff --git a/libguile/dynl.c b/libguile/dynl.c
index 0637b1217..5fd44e320 100644
--- a/libguile/dynl.c
+++ b/libguile/dynl.c
@@ -302,7 +302,6 @@ mark_dynl_obj (ptr)
      SCM ptr;
 {
     struct dynl_obj *d = (struct dynl_obj *)SCM_CDR (ptr);
-    SCM_SETGC8MARK (ptr);
     return d->filename;
 }
 
diff --git a/libguile/dynwind.c b/libguile/dynwind.c
index 832c77466..f0c3be986 100644
--- a/libguile/dynwind.c
+++ b/libguile/dynwind.c
@@ -119,7 +119,7 @@ printguards (SCM exp, SCM port, scm_print_state *pstate)
 }
 
 static scm_smobfuns guardsmob = {
-  scm_mark0,
+  0,
   freeguards,
   printguards,
   0
diff --git a/libguile/filesys.c b/libguile/filesys.c
index dff946f08..8eca66bb6 100644
--- a/libguile/filesys.c
+++ b/libguile/filesys.c
@@ -832,7 +832,7 @@ scm_dir_free (p)
   return 0;
 }
 
-static scm_smobfuns dir_smob = {scm_mark0, scm_dir_free, scm_dir_print, 0};
+static scm_smobfuns dir_smob = {0, scm_dir_free, scm_dir_print, 0};
 
 
 /* {Navigating Directories}
diff --git a/libguile/fluids.c b/libguile/fluids.c
index c07d01d9d..601ca8b93 100644
--- a/libguile/fluids.c
+++ b/libguile/fluids.c
@@ -107,7 +107,7 @@ print_fluid (exp, port, pstate)
 }
 
 static scm_smobfuns fluid_smob = {
-    scm_mark0,
+    0,
     scm_free0,
     print_fluid
 };
diff --git a/libguile/fports.c b/libguile/fports.c
index 1fd0d27e3..ec87bda8e 100644
--- a/libguile/fports.c
+++ b/libguile/fports.c
@@ -458,7 +458,7 @@ local_pclose (fp)
 
 scm_ptobfuns scm_fptob =
 {
-  scm_mark0,
+  0,
   (int (*) SCM_P ((SCM))) local_fclose,
   prinfport,
   0,
@@ -474,7 +474,7 @@ scm_ptobfuns scm_fptob =
 /* {Pipe ports} */
 scm_ptobfuns scm_pipob =
 {
-  scm_mark0,
+  0,
   (int (*) SCM_P ((SCM))) local_pclose,  
   print_pipe_port,
   0,
diff --git a/libguile/gc.c b/libguile/gc.c
index 16de3d978..988379c8b 100644
--- a/libguile/gc.c
+++ b/libguile/gc.c
@@ -819,31 +819,41 @@ gc_mark_nimp:
 	goto def;
       if (SCM_GC8MARKP (ptr))
 	break;
+      SCM_SETGC8MARK (ptr);
       if (SCM_PTAB_ENTRY(ptr))
 	scm_gc_mark (SCM_PTAB_ENTRY(ptr)->file_name);
-      ptr = (scm_ptobs[i].mark) (ptr);
-      goto gc_mark_loop;
+      if (scm_ptobs[i].mark)
+	{
+	  ptr = (scm_ptobs[i].mark) (ptr);
+	  goto gc_mark_loop;
+	}
+      else
+	return;
       break;
     case scm_tc7_smob:
       if (SCM_GC8MARKP (ptr))
 	break;
-      switch SCM_TYP16 (ptr)
+      SCM_SETGC8MARK (ptr);
+      switch SCM_GCTYP16 (ptr)
 	{ /* should be faster than going through scm_smobs */
 	case scm_tc_free_cell:
 	  /* printf("found free_cell %X ", ptr); fflush(stdout); */
-	  SCM_SETGC8MARK (ptr);
 	  SCM_SETCDR (ptr, SCM_EOL);
 	  break;
 	case scm_tcs_bignums:
 	case scm_tc16_flo:
-	  SCM_SETGC8MARK (ptr);
 	  break;
 	default:
 	  i = SCM_SMOBNUM (ptr);
 	  if (!(i < scm_numsmob))
 	    goto def;
-	  ptr = (scm_smobs[i].mark) (ptr);
-	  goto gc_mark_loop;
+	  if (scm_smobs[i].mark)
+	    {
+	      ptr = (scm_smobs[i].mark) (ptr);
+	      goto gc_mark_loop;
+	    }
+	  else
+	    return;
 	}
       break;
     default:
diff --git a/libguile/mallocs.c b/libguile/mallocs.c
index b2f48cdd8..c7c2b6fa1 100644
--- a/libguile/mallocs.c
+++ b/libguile/mallocs.c
@@ -66,7 +66,7 @@ prinmalloc (exp, port, pstate)
 
 
 int scm_tc16_malloc;
-static scm_smobfuns mallocsmob = {scm_mark0, fmalloc, prinmalloc, 0};
+static scm_smobfuns mallocsmob = {0, fmalloc, prinmalloc, 0};
 
 
 
diff --git a/libguile/markers.c b/libguile/markers.c
index 0b1aa57e3..8967811e7 100644
--- a/libguile/markers.c
+++ b/libguile/markers.c
@@ -50,11 +50,20 @@
  */
 
 
+/* This function is vestigial.  It used to be the mark function's
+   responsibility to set the mark bit on the smob or port, but now the
+   generic marking routine in gc.c takes care of that, and a zero
+   pointer for a mark function means "don't bother".  So you never
+   need scm_mark0.
+
+   However, we leave it here because it's harmless to call it, and
+   people out there have smob code that uses it, and there's no reason
+   to make their links fail.  */
+
 SCM 
 scm_mark0 (ptr)
      SCM ptr;
 {
-  SCM_SETGC8MARK (ptr);
   return SCM_BOOL_F;
 }
 
@@ -64,9 +73,6 @@ SCM
 scm_markcdr (ptr)
      SCM ptr;
 {
-  if (SCM_GC8MARKP (ptr))
-    return SCM_BOOL_F;
-  SCM_SETGC8MARK (ptr);
   return SCM_CDR (ptr);
 }
 
diff --git a/libguile/ports.c b/libguile/ports.c
index ea95305b9..52722862d 100644
--- a/libguile/ports.c
+++ b/libguile/ports.c
@@ -81,10 +81,7 @@ scm_markstream (ptr)
      SCM ptr;
 {
   int openp;
-  if (SCM_GC8MARKP (ptr))
-    return SCM_BOOL_F;
   openp = SCM_CAR (ptr) & SCM_OPN;
-  SCM_SETGC8MARK (ptr);
   if (openp)
     return SCM_STREAM  (ptr);
   else
@@ -895,7 +892,7 @@ noop0 (SCM stream)
 
 static struct scm_ptobfuns  void_port_ptob =
 {
-  scm_mark0, 
+  0, 
   noop0,
   print_void_port,
   0,				/* equal? */
diff --git a/libguile/regex-posix.c b/libguile/regex-posix.c
index f72efe455..d01b4e0ca 100644
--- a/libguile/regex-posix.c
+++ b/libguile/regex-posix.c
@@ -112,7 +112,7 @@ scm_print_regex_t (obj, port, pstate)
 
 
 static scm_smobfuns regex_t_smob =
-{ scm_mark0, scm_free_regex_t, scm_print_regex_t, 0 };
+{ 0, scm_free_regex_t, scm_print_regex_t, 0 };
 
 
 SCM_SYMBOL (scm_regexp_error_key, "regular-expression-syntax");
diff --git a/libguile/root.c b/libguile/root.c
index 22a88f392..00f69bf03 100644
--- a/libguile/root.c
+++ b/libguile/root.c
@@ -77,7 +77,7 @@ mark_root (root)
      SCM root;
 {
   scm_root_state *s = SCM_ROOT_STATE (root);
-  SCM_SETGC8MARK (root);
+
   scm_gc_mark (s->rootcont);
   scm_gc_mark (s->dynwinds);
   scm_gc_mark (s->continuation_stack);
diff --git a/libguile/smob.c b/libguile/smob.c
index 25c8669de..a498c48b4 100644
--- a/libguile/smob.c
+++ b/libguile/smob.c
@@ -89,7 +89,7 @@ scm_newsmob (smob)
 
 static scm_smobfuns freecell =
 {
-  scm_mark0,
+  0,
   scm_free0,
   0,
   0
@@ -97,7 +97,7 @@ static scm_smobfuns freecell =
 
 static scm_smobfuns flob =
 {
-  scm_mark0,
+  0,
   /*flofree*/ 0,
   scm_floprint,
   scm_floequal
@@ -105,7 +105,7 @@ static scm_smobfuns flob =
 
 static scm_smobfuns bigob =
 {
-  scm_mark0,
+  0,
   /*bigfree*/ 0,
   scm_bigprint,
   scm_bigequal
diff --git a/libguile/srcprop.c b/libguile/srcprop.c
index 195b69964..b13e43d23 100644
--- a/libguile/srcprop.c
+++ b/libguile/srcprop.c
@@ -86,7 +86,6 @@ static SCM
 marksrcprops (obj)
      SCM obj;
 {
-  SCM_SETGC8MARK (obj);
   scm_gc_mark (SRCPROPFNAME (obj));
   scm_gc_mark (SRCPROPCOPY (obj));
   return SRCPROPPLIST (obj);
diff --git a/libguile/threads.c b/libguile/threads.c
index 11fb87f99..c262c7ca7 100644
--- a/libguile/threads.c
+++ b/libguile/threads.c
@@ -95,7 +95,7 @@ print_thread (exp, port, pstate)
 
 static scm_smobfuns thread_smob =
 {
-  scm_mark0,
+  0,
   scm_threads_free_thread,
   print_thread,
   0
@@ -115,7 +115,7 @@ print_mutex (exp, port, pstate)
 
 static scm_smobfuns mutex_smob =
 {
-  scm_mark0,
+  0,
   scm_threads_free_mutex,
   print_mutex,
   0
@@ -135,7 +135,7 @@ print_condvar (exp, port, pstate)
 
 static scm_smobfuns condvar_smob =
 {
-  scm_mark0,
+  0,
   scm_threads_free_condvar,
   print_condvar,
   0
diff --git a/libguile/throw.c b/libguile/throw.c
index bd15f2a09..a55e043ea 100644
--- a/libguile/throw.c
+++ b/libguile/throw.c
@@ -103,7 +103,7 @@ printjb (exp, port, pstate)
 }
 
 static scm_smobfuns jbsmob = {
-  scm_mark0,
+  0,
 #ifdef DEBUG_EXTENSIONS
   freejb,
 #else
@@ -280,7 +280,7 @@ print_lazy_catch (SCM closure, SCM port, scm_print_state *pstate)
 }
 
 static scm_smobfuns lazy_catch_funs = {
-  scm_mark0, scm_free0, print_lazy_catch, 0
+  0, scm_free0, print_lazy_catch, 0
 };
 
 
diff --git a/libguile/unif.c b/libguile/unif.c
index 5cd9e0b28..cc0fbb38b 100644
--- a/libguile/unif.c
+++ b/libguile/unif.c
@@ -2532,9 +2532,6 @@ static SCM
 markra (ptr)
      SCM ptr;
 {
-  if SCM_GC8MARKP
-    (ptr) return SCM_BOOL_F;
-  SCM_SETGC8MARK (ptr);
   return SCM_ARRAY_V (ptr);
 }
 
diff --git a/libguile/variable.c b/libguile/variable.c
index 02f9a5caa..922647eeb 100644
--- a/libguile/variable.c
+++ b/libguile/variable.c
@@ -92,9 +92,6 @@ static SCM
 scm_markvar (ptr)
      SCM ptr;
 {
-  if (SCM_GC8MARKP (ptr))
-    return SCM_BOOL_F;
-  SCM_SETGC8MARK (ptr);
   return SCM_CDR (ptr);
 }
 
-- 
2.20.1