From 91f9635c1e8f649839a005b0468c1d77c2c87987 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Thu, 24 Jan 2008 15:21:33 +0000
Subject: [PATCH] fix GC bug related to park[] and finalization

svn: r8397
---
 src/mzscheme/gc2/compact.c | 14 +++++++++++++-
 src/mzscheme/gc2/newgc.c   | 15 ++++++++++++++-
 src/mzscheme/src/schemef.h |  4 ++--
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/mzscheme/gc2/compact.c b/src/mzscheme/gc2/compact.c
index fc0d1258ff..90d66ce4b5 100644
--- a/src/mzscheme/gc2/compact.c
+++ b/src/mzscheme/gc2/compact.c
@@ -386,7 +386,7 @@ static int running_finals;
 static char zero_sized[4];
 
 /* Temporary pointer-holder used by routines that allocate */
-static void *park[2];
+static void *park[2], *park_save[2];
 
 static int during_gc, avoid_collection;
 
@@ -2825,6 +2825,7 @@ static void init(void)
     GC_add_roots(&run_queue, (char *)&run_queue + sizeof(run_queue) + 1);
     GC_add_roots(&last_in_queue, (char *)&last_in_queue + sizeof(last_in_queue) + 1);
     GC_add_roots(&park, (char *)&park + sizeof(park) + 1);
+    GC_add_roots(&park_save, (char *)&park_save + sizeof(park_save) + 1);
 
     sets[0] = &tagged;
     sets[1] = &array;
@@ -3487,6 +3488,12 @@ static void gcollect(int full)
   if (!running_finals) {
     running_finals = 1;
 
+    /* Finalization might allocate, which might need park: */
+    park_save[0] = park[0];
+    park_save[1] = park[1];
+    park[0] = NULL;
+    park[1] = NULL;
+
     while (run_queue) {
       Fnl *f;
       void **gcs;
@@ -3505,6 +3512,11 @@ static void gcollect(int full)
     }
 
     running_finals = 0;
+
+    park[0] = park_save[0];
+    park[1] = park_save[1];
+    park_save[0] = NULL;
+    park_save[1] = NULL;
   }
 }
 
diff --git a/src/mzscheme/gc2/newgc.c b/src/mzscheme/gc2/newgc.c
index 331f965eae..2e6aa0784b 100644
--- a/src/mzscheme/gc2/newgc.c
+++ b/src/mzscheme/gc2/newgc.c
@@ -136,7 +136,7 @@ void (*GC_fixup_xtagged)(void *obj);
 
 #include "my_qsort.c"
 
-static void *park[2];
+static void *park[2], *park_save[2];
 
 /*****************************************************************************/
 /* OS-Level Memory Management Routines                                       */
@@ -2117,6 +2117,7 @@ void GC_init_type_tags(int count, int pair, int mutable_pair, int weakbox, int e
 			   fixup_weak_array, 0, 0);
     initialize_signal_handler();
     GC_add_roots(&park, (char *)&park + sizeof(park) + 1);
+    GC_add_roots(&park_save, (char *)&park_save + sizeof(park_save) + 1);
 
     initialize_protect_page_ranges(malloc_dirty_pages(APAGE_SIZE, APAGE_SIZE), APAGE_SIZE);
   }
@@ -3202,6 +3203,13 @@ static void garbage_collect(int force_full)
      finalizer completes its execution */
   if(!running_finalizers) {
     running_finalizers = 1;
+
+    /* Finalization might allocate, which might need park: */
+    park_save[0] = park[0];
+    park_save[1] = park[1];
+    park[0] = NULL;
+    park[1] = NULL;
+
     while(run_queue) {
       struct finalizer *f;
       void **gcs;
@@ -3217,6 +3225,11 @@ static void garbage_collect(int force_full)
     }
     run_account_hooks();
     running_finalizers = 0;
+
+    park[0] = park_save[0];
+    park[1] = park_save[1];
+    park_save[0] = NULL;
+    park_save[1] = NULL;
   }
 
   DUMP_HEAP(); CLOSE_DEBUG_FILE();
diff --git a/src/mzscheme/src/schemef.h b/src/mzscheme/src/schemef.h
index 30762e87df..34869703d3 100644
--- a/src/mzscheme/src/schemef.h
+++ b/src/mzscheme/src/schemef.h
@@ -615,8 +615,8 @@ MZ_EXTERN Scheme_Object *scheme_rational_from_float(float d);
 # define scheme_rational_from_float scheme_rational_from_double
 #endif
 MZ_EXTERN Scheme_Object *scheme_rational_normalize(const Scheme_Object *n);
-MZ_EXTERN Scheme_Object *scheme_rational_numerator(const Scheme_Object *n);
-MZ_EXTERN Scheme_Object *scheme_rational_denominator(const Scheme_Object *n);
+XFORM_NONGCING MZ_EXTERN Scheme_Object *scheme_rational_numerator(const Scheme_Object *n);
+XFORM_NONGCING MZ_EXTERN Scheme_Object *scheme_rational_denominator(const Scheme_Object *n);
 
 /*========================================================================*/
 /*                              complexes                                 */