0.9.17.8:
[sbcl.git] / src / runtime / gencgc.c
index d39bf9b..6902759 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * GENerational Conservative Garbage Collector for SBCL x86
+ * GENerational Conservative Garbage Collector for SBCL
  */
 
 /*
 #include "thread.h"
 #include "genesis/vector.h"
 #include "genesis/weak-pointer.h"
+#include "genesis/fdefn.h"
 #include "genesis/simple-fun.h"
 #include "save.h"
 #include "genesis/hash-table.h"
+#include "genesis/instance.h"
+#include "genesis/layout.h"
+
+#ifdef LUTEX_WIDETAG
+#include "genesis/lutex.h"
+#endif
 
 /* forward declarations */
 page_index_t  gc_find_freeish_pages(long *restart_page_ptr, long nbytes,
@@ -70,22 +77,6 @@ enum {
  * that don't have pointers to younger generations? */
 boolean enable_page_protection = 1;
 
-/* Should we unmap a page and re-mmap it to have it zero filled? */
-#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__sun)
-/* comment from cmucl-2.4.8: This can waste a lot of swap on FreeBSD
- * so don't unmap there.
- *
- * The CMU CL comment didn't specify a version, but was probably an
- * old version of FreeBSD (pre-4.0), so this might no longer be true.
- * OTOH, if it is true, this behavior might exist on OpenBSD too, so
- * for now we don't unmap there either. -- WHN 2001-04-07 */
-/* Apparently this flag is required to be 0 for SunOS/x86, as there
- * are reports of heap corruption otherwise. */
-boolean gencgc_unmap_zero = 0;
-#else
-boolean gencgc_unmap_zero = 1;
-#endif
-
 /* the minimum size (in bytes) for a large object*/
 unsigned long large_object_size = 4 * PAGE_BYTES;
 
@@ -139,6 +130,13 @@ boolean gencgc_zero_check_during_free_heap = 0;
  * contained a pagetable entry).
  */
 boolean gencgc_partial_pickup = 0;
+
+/* If defined, free pages are read-protected to ensure that nothing
+ * accesses them.
+ */
+
+/* #define READ_PROTECT_FREE_PAGES */
+
 \f
 /*
  * GC structures and variables
@@ -154,6 +152,9 @@ unsigned long auto_gc_trigger = 0;
 generation_index_t from_space;
 generation_index_t new_space;
 
+/* Set to 1 when in GC */
+boolean gc_active_p = 0;
+
 /* should the GC be conservative on stack. If false (only right before
  * saving a core), don't scan the stack / mark pages dont_move. */
 static boolean conservative_stack = 1;
@@ -167,12 +168,6 @@ struct page page_table[NUM_PAGES];
  * is needed. */
 static void *heap_base = NULL;
 
-#if N_WORD_BITS == 32
- #define SIMPLE_ARRAY_WORD_WIDETAG SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG
-#elif N_WORD_BITS == 64
- #define SIMPLE_ARRAY_WORD_WIDETAG SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
-#endif
-
 /* Calculate the start address for the given page number. */
 inline void *
 page_address(page_index_t page_num)
@@ -241,6 +236,14 @@ struct generation {
      * prevent a GC when a large number of new live objects have been
      * added, in which case a GC could be a waste of time */
     double min_av_mem_age;
+
+    /* A linked list of lutex structures in this generation, used for
+     * implementing lutex finalization. */
+#ifdef LUTEX_WIDETAG
+    struct lutex *lutexes;
+#else
+    void *lutexes;
+#endif
 };
 
 /* an array of generation structures. There needs to be one more
@@ -308,7 +311,7 @@ count_generation_pages(generation_index_t generation)
     long count = 0;
 
     for (i = 0; i < last_free_page; i++)
-        if ((page_table[i].allocated != 0)
+        if ((page_table[i].allocated != FREE_PAGE_FLAG)
             && (page_table[i].gen == generation))
             count++;
     return count;
@@ -321,7 +324,8 @@ count_dont_move_pages(void)
     page_index_t i;
     long count = 0;
     for (i = 0; i < last_free_page; i++) {
-        if ((page_table[i].allocated != 0) && (page_table[i].dont_move != 0)) {
+        if ((page_table[i].allocated != FREE_PAGE_FLAG)
+            && (page_table[i].dont_move != 0)) {
             ++count;
         }
     }
@@ -337,7 +341,8 @@ count_generation_bytes_allocated (generation_index_t gen)
     page_index_t i;
     long result = 0;
     for (i = 0; i < last_free_page; i++) {
-        if ((page_table[i].allocated != 0) && (page_table[i].gen == gen))
+        if ((page_table[i].allocated != FREE_PAGE_FLAG)
+            && (page_table[i].gen == gen))
             result += page_table[i].bytes_used;
     }
     return result;
@@ -355,15 +360,20 @@ gen_av_mem_age(generation_index_t gen)
         / ((double)generations[gen].bytes_allocated);
 }
 
-void fpu_save(int *);           /* defined in x86-assem.S */
-void fpu_restore(int *);        /* defined in x86-assem.S */
 /* The verbose argument controls how much to print: 0 for normal
  * level of detail; 1 for debugging. */
 static void
 print_generation_stats(int verbose) /* FIXME: should take FILE argument */
 {
     generation_index_t i, gens;
-    int fpu_state[27];
+
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
+#define FPU_STATE_SIZE 27
+    int fpu_state[FPU_STATE_SIZE];
+#elif defined(LISP_FEATURE_PPC)
+#define FPU_STATE_SIZE 32
+    long long fpu_state[FPU_STATE_SIZE];
+#endif
 
     /* This code uses the FP instructions which may be set up for Lisp
      * so they need to be saved and reset for C. */
@@ -377,7 +387,7 @@ print_generation_stats(int verbose) /* FIXME: should take FILE argument */
 
     /* Print the heap stats. */
     fprintf(stderr,
-            "   Gen Boxed Unboxed LB   LUB  !move  Alloc  Waste   Trig    WP  GCs Mem-age\n");
+            " Gen StaPg UbSta LaSta LUbSt Boxed Unboxed LB   LUB  !move  Alloc  Waste   Trig    WP  GCs Mem-age\n");
 
     for (i = 0; i < gens; i++) {
         page_index_t j;
@@ -412,13 +422,19 @@ print_generation_stats(int verbose) /* FIXME: should take FILE argument */
         gc_assert(generations[i].bytes_allocated
                   == count_generation_bytes_allocated(i));
         fprintf(stderr,
-                "   %1d: %5ld %5ld %5ld %5ld %5ld %8ld %5ld %8ld %4ld %3d %7.4f\n",
+                "   %1d: %5ld %5ld %5ld %5ld %5ld %5ld %5ld %5ld %5ld %8ld %5ld %8ld %4ld %3d %7.4f\n",
                 i,
-                boxed_cnt, unboxed_cnt, large_boxed_cnt, large_unboxed_cnt,
+                generations[i].alloc_start_page,
+                generations[i].alloc_unboxed_start_page,
+                generations[i].alloc_large_start_page,
+                generations[i].alloc_large_unboxed_start_page,
+                boxed_cnt,
+                unboxed_cnt,
+                large_boxed_cnt,
+                large_unboxed_cnt,
                 pinned_cnt,
                 generations[i].bytes_allocated,
-                (count_generation_pages(i)*PAGE_BYTES
-                 - generations[i].bytes_allocated),
+                (count_generation_pages(i)*PAGE_BYTES - generations[i].bytes_allocated),
                 generations[i].gc_trigger,
                 count_write_protect_generation_pages(i),
                 generations[i].num_gc,
@@ -429,9 +445,70 @@ print_generation_stats(int verbose) /* FIXME: should take FILE argument */
     fpu_restore(fpu_state);
 }
 \f
-/*
- * allocation routines
+
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
+void fast_bzero(void*, size_t); /* in <arch>-assem.S */
+#endif
+
+/* Zero the pages from START to END (inclusive), but use mmap/munmap instead
+ * if zeroing it ourselves, i.e. in practice give the memory back to the
+ * OS. Generally done after a large GC.
+ */
+void zero_pages_with_mmap(page_index_t start, page_index_t end) {
+    int i;
+    void *addr = (void *) page_address(start), *new_addr;
+    size_t length = PAGE_BYTES*(1+end-start);
+
+    if (start > end)
+      return;
+
+    os_invalidate(addr, length);
+    new_addr = os_validate(addr, length);
+    if (new_addr == NULL || new_addr != addr) {
+        lose("remap_free_pages: page moved, 0x%08x ==> 0x%08x", start, new_addr);
+    }
+
+    for (i = start; i <= end; i++) {
+        page_table[i].need_to_zero = 0;
+    }
+}
+
+/* Zero the pages from START to END (inclusive). Generally done just after
+ * a new region has been allocated.
+ */
+static void
+zero_pages(page_index_t start, page_index_t end) {
+    if (start > end)
+      return;
+
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
+    fast_bzero(page_address(start), PAGE_BYTES*(1+end-start));
+#else
+    bzero(page_address(start), PAGE_BYTES*(1+end-start));
+#endif
+
+}
+
+/* Zero the pages from START to END (inclusive), except for those
+ * pages that are known to already zeroed. Mark all pages in the
+ * ranges as non-zeroed.
  */
+static void
+zero_dirty_pages(page_index_t start, page_index_t end) {
+    page_index_t i;
+
+    for (i = start; i <= end; i++) {
+        if (page_table[i].need_to_zero == 1) {
+            zero_pages(start, end);
+            break;
+        }
+    }
+
+    for (i = start; i <= end; i++) {
+        page_table[i].need_to_zero = 1;
+    }
+}
+
 
 /*
  * To support quick and inline allocation, regions of memory can be
@@ -517,6 +594,7 @@ gc_alloc_new_region(long nbytes, int unboxed, struct alloc_region *alloc_region)
     page_index_t last_page;
     long bytes_found;
     page_index_t i;
+    int ret;
 
     /*
     FSHOW((stderr,
@@ -528,7 +606,8 @@ gc_alloc_new_region(long nbytes, int unboxed, struct alloc_region *alloc_region)
     gc_assert((alloc_region->first_page == 0)
               && (alloc_region->last_page == -1)
               && (alloc_region->free_pointer == alloc_region->end_addr));
-    thread_mutex_lock(&free_pages_lock);
+    ret = thread_mutex_lock(&free_pages_lock);
+    gc_assert(ret == 0);
     if (unboxed) {
         first_page =
             generations[gc_alloc_generation].alloc_unboxed_start_page;
@@ -586,11 +665,11 @@ gc_alloc_new_region(long nbytes, int unboxed, struct alloc_region *alloc_region)
     /* Bump up last_free_page. */
     if (last_page+1 > last_free_page) {
         last_free_page = last_page+1;
-        SetSymbolValue(ALLOCATION_POINTER,
-                       (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),
-                       0);
+        /* do we only want to call this on special occasions? like for boxed_region? */
+        set_alloc_pointer((lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES));
     }
-    thread_mutex_unlock(&free_pages_lock);
+    ret = thread_mutex_unlock(&free_pages_lock);
+    gc_assert(ret == 0);
 
     /* we can do this after releasing free_pages_lock */
     if (gencgc_zero_check) {
@@ -602,10 +681,26 @@ gc_alloc_new_region(long nbytes, int unboxed, struct alloc_region *alloc_region)
                  * (long) in code like this, so that it is less likely to
                  * break randomly when running on a machine with different
                  * word sizes. -- WHN 19991129 */
-                lose("The new region at %x is not zero.", p);
+                lose("The new region at %x is not zero.\n", p);
             }
         }
     }
+
+#ifdef READ_PROTECT_FREE_PAGES
+    os_protect(page_address(first_page),
+               PAGE_BYTES*(1+last_page-first_page),
+               OS_VM_PROT_ALL);
+#endif
+
+    /* If the first page was only partial, don't check whether it's
+     * zeroed (it won't be) and don't zero it (since the parts that
+     * we're interested in are guaranteed to be zeroed).
+     */
+    if (page_table[first_page].bytes_used) {
+        first_page++;
+    }
+
+    zero_dirty_pages(first_page, last_page);
 }
 
 /* If the record_new_objects flag is 2 then all new regions created
@@ -716,6 +811,7 @@ gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
     long orig_first_page_bytes_used;
     long region_size;
     long byte_cnt;
+    int ret;
 
 
     first_page = alloc_region->first_page;
@@ -726,7 +822,8 @@ gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
 
     next_page = first_page+1;
 
-    thread_mutex_lock(&free_pages_lock);
+    ret = thread_mutex_lock(&free_pages_lock);
+    gc_assert(ret == 0);
     if (alloc_region->free_pointer != alloc_region->start_addr) {
         /* some bytes were allocated in the region */
         orig_first_page_bytes_used = page_table[first_page].bytes_used;
@@ -830,7 +927,9 @@ gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
         page_table[next_page].allocated = FREE_PAGE_FLAG;
         next_page++;
     }
-    thread_mutex_unlock(&free_pages_lock);
+    ret = thread_mutex_unlock(&free_pages_lock);
+    gc_assert(ret == 0);
+
     /* alloc_region is per-thread, we're ok to do this unlocked */
     gc_set_region_empty(alloc_region);
 }
@@ -848,8 +947,10 @@ gc_alloc_large(long nbytes, int unboxed, struct alloc_region *alloc_region)
     int more;
     long bytes_used;
     page_index_t next_page;
+    int ret;
 
-    thread_mutex_lock(&free_pages_lock);
+    ret = thread_mutex_lock(&free_pages_lock);
+    gc_assert(ret == 0);
 
     if (unboxed) {
         first_page =
@@ -947,16 +1048,50 @@ gc_alloc_large(long nbytes, int unboxed, struct alloc_region *alloc_region)
     /* Bump up last_free_page */
     if (last_page+1 > last_free_page) {
         last_free_page = last_page+1;
-        SetSymbolValue(ALLOCATION_POINTER,
-                       (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
+        set_alloc_pointer((lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES));
     }
-    thread_mutex_unlock(&free_pages_lock);
+    ret = thread_mutex_unlock(&free_pages_lock);
+    gc_assert(ret == 0);
+
+#ifdef READ_PROTECT_FREE_PAGES
+    os_protect(page_address(first_page),
+               PAGE_BYTES*(1+last_page-first_page),
+               OS_VM_PROT_ALL);
+#endif
+
+    zero_dirty_pages(first_page, last_page);
 
-    return((void *)(page_address(first_page)+orig_first_page_bytes_used));
+    return page_address(first_page);
 }
 
 static page_index_t gencgc_alloc_start_page = -1;
 
+void
+gc_heap_exhausted_error_or_lose (long available, long requested)
+{
+    /* Write basic information before doing anything else: if we don't
+     * call to lisp this is a must, and even if we do there is always the
+     * danger that we bounce back here before the error has been handled,
+     * or indeed even printed.
+     */
+    fprintf(stderr, "Heap exhausted during %s: %ld bytes available, %ld requested.\n",
+            gc_active_p ? "garbage collection" : "allocation", available, requested);
+    if (gc_active_p || (available == 0)) {
+        /* If we are in GC, or totally out of memory there is no way
+         * to sanely transfer control to the lisp-side of things.
+         */
+        print_generation_stats(1);
+        lose("Heap exhausted, game over.");
+    }
+    else {
+        /* FIXME: assert free_pages_lock held */
+        thread_mutex_unlock(&free_pages_lock);
+        funcall2(SymbolFunction(HEAP_EXHAUSTED_ERROR),
+                 make_fixnum(available), make_fixnum(requested));
+        lose("HEAP-EXHAUSTED-ERROR fell through");
+    }
+}
+
 page_index_t
 gc_find_freeish_pages(page_index_t *restart_page_ptr, long nbytes, int unboxed)
 {
@@ -999,13 +1134,8 @@ gc_find_freeish_pages(page_index_t *restart_page_ptr, long nbytes, int unboxed)
                 first_page++;
             }
 
-        if (first_page >= NUM_PAGES) {
-            fprintf(stderr,
-                    "Argh! gc_find_free_space failed (first_page), nbytes=%ld.\n",
-                    nbytes);
-            print_generation_stats(1);
-            lose(NULL);
-        }
+        if (first_page >= NUM_PAGES)
+            gc_heap_exhausted_error_or_lose(0, nbytes);
 
         gc_assert(page_table[first_page].write_protected == 0);
 
@@ -1030,13 +1160,9 @@ gc_find_freeish_pages(page_index_t *restart_page_ptr, long nbytes, int unboxed)
     } while ((restart_page < NUM_PAGES) && (bytes_found < nbytes));
 
     /* Check for a failure */
-    if ((restart_page >= NUM_PAGES) && (bytes_found < nbytes)) {
-        fprintf(stderr,
-                "Argh! gc_find_freeish_pages failed (restart_page), nbytes=%ld.\n",
-                nbytes);
-        print_generation_stats(1);
-        lose(NULL);
-    }
+    if ((restart_page >= NUM_PAGES) && (bytes_found < nbytes))
+        gc_heap_exhausted_error_or_lose(bytes_found, nbytes);
+
     *restart_page_ptr=first_page;
 
     return last_page;
@@ -1726,219 +1852,176 @@ trans_unboxed_large(lispobj object)
 
 \f
 /*
- * vector-like objects
+ * Lutexes. Using the normal finalization machinery for finalizing
+ * lutexes is tricky, since the finalization depends on working lutexes.
+ * So we track the lutexes in the GC and finalize them manually.
  */
 
+#if defined(LUTEX_WIDETAG)
 
-/* FIXME: What does this mean? */
-int gencgc_hash = 1;
+/*
+ * Start tracking LUTEX in the GC, by adding it to the linked list of
+ * lutexes in the nursery generation. The caller is responsible for
+ * locking, and GCs must be inhibited until the registration is
+ * complete.
+ */
+void
+gencgc_register_lutex (struct lutex *lutex) {
+    int index = find_page_index(lutex);
+    generation_index_t gen;
+    struct lutex *head;
 
-static long
-scav_vector(lispobj *where, lispobj object)
-{
-    unsigned long kv_length;
-    lispobj *kv_vector;
-    unsigned long length = 0; /* (0 = dummy to stop GCC warning) */
-    struct hash_table *hash_table;
-    lispobj empty_symbol;
-    unsigned long *index_vector = NULL; /* (NULL = dummy to stop GCC warning) */
-    unsigned long *next_vector = NULL; /* (NULL = dummy to stop GCC warning) */
-    unsigned long *hash_vector = NULL; /* (NULL = dummy to stop GCC warning) */
-    lispobj weak_p_obj;
-    unsigned long next_vector_length = 0;
-
-    /* FIXME: A comment explaining this would be nice. It looks as
-     * though SB-VM:VECTOR-VALID-HASHING-SUBTYPE is set for EQ-based
-     * hash tables in the Lisp HASH-TABLE code, and nowhere else. */
-    if (HeaderValue(object) != subtype_VectorValidHashing)
-        return 1;
+    /* This lutex is in static space, so we don't need to worry about
+     * finalizing it.
+     */
+    if (index == -1)
+        return;
 
-    if (!gencgc_hash) {
-        /* This is set for backward compatibility. FIXME: Do we need
-         * this any more? */
-        *where =
-            (subtype_VectorMustRehash<<N_WIDETAG_BITS) | SIMPLE_VECTOR_WIDETAG;
-        return 1;
-    }
+    gen = page_table[index].gen;
 
-    kv_length = fixnum_value(where[1]);
-    kv_vector = where + 2;  /* Skip the header and length. */
-    /*FSHOW((stderr,"/kv_length = %d\n", kv_length));*/
+    gc_assert(gen >= 0);
+    gc_assert(gen < NUM_GENERATIONS);
 
-    /* Scavenge element 0, which may be a hash-table structure. */
-    scavenge(where+2, 1);
-    if (!is_lisp_pointer(where[2])) {
-        lose("no pointer at %x in hash table", where[2]);
-    }
-    hash_table = (struct hash_table *)native_pointer(where[2]);
-    /*FSHOW((stderr,"/hash_table = %x\n", hash_table));*/
-    if (widetag_of(hash_table->header) != INSTANCE_HEADER_WIDETAG) {
-        lose("hash table not instance (%x at %x)",
-             hash_table->header,
-             hash_table);
-    }
+    head = generations[gen].lutexes;
 
-    /* Scavenge element 1, which should be some internal symbol that
-     * the hash table code reserves for marking empty slots. */
-    scavenge(where+3, 1);
-    if (!is_lisp_pointer(where[3])) {
-        lose("not empty-hash-table-slot symbol pointer: %x", where[3]);
-    }
-    empty_symbol = where[3];
-    /* fprintf(stderr,"* empty_symbol = %x\n", empty_symbol);*/
-    if (widetag_of(*(lispobj *)native_pointer(empty_symbol)) !=
-        SYMBOL_HEADER_WIDETAG) {
-        lose("not a symbol where empty-hash-table-slot symbol expected: %x",
-             *(lispobj *)native_pointer(empty_symbol));
-    }
+    lutex->gen = gen;
+    lutex->next = head;
+    lutex->prev = NULL;
+    if (head)
+        head->prev = lutex;
+    generations[gen].lutexes = lutex;
+}
 
-    /* Scavenge hash table, which will fix the positions of the other
-     * needed objects. */
-    scavenge((lispobj *)hash_table,
-             sizeof(struct hash_table) / sizeof(lispobj));
+/*
+ * Stop tracking LUTEX in the GC by removing it from the appropriate
+ * linked lists. This will only be called during GC, so no locking is
+ * needed.
+ */
+void
+gencgc_unregister_lutex (struct lutex *lutex) {
+    if (lutex->prev) {
+        lutex->prev->next = lutex->next;
+    } else {
+        generations[lutex->gen].lutexes = lutex->next;
+    }
 
-    /* Cross-check the kv_vector. */
-    if (where != (lispobj *)native_pointer(hash_table->table)) {
-        lose("hash_table table!=this table %x", hash_table->table);
+    if (lutex->next) {
+        lutex->next->prev = lutex->prev;
     }
 
-    /* WEAK-P */
-    weak_p_obj = hash_table->weak_p;
+    lutex->next = NULL;
+    lutex->prev = NULL;
+    lutex->gen = -1;
+}
 
-    /* index vector */
-    {
-        lispobj index_vector_obj = hash_table->index_vector;
-
-        if (is_lisp_pointer(index_vector_obj) &&
-            (widetag_of(*(lispobj *)native_pointer(index_vector_obj)) ==
-                 SIMPLE_ARRAY_WORD_WIDETAG)) {
-            index_vector =
-                ((unsigned long *)native_pointer(index_vector_obj)) + 2;
-            /*FSHOW((stderr, "/index_vector = %x\n",index_vector));*/
-            length = fixnum_value(((lispobj *)native_pointer(index_vector_obj))[1]);
-            /*FSHOW((stderr, "/length = %d\n", length));*/
-        } else {
-            lose("invalid index_vector %x", index_vector_obj);
-        }
+/*
+ * Mark all lutexes in generation GEN as not live.
+ */
+static void
+unmark_lutexes (generation_index_t gen) {
+    struct lutex *lutex = generations[gen].lutexes;
+
+    while (lutex) {
+        lutex->live = 0;
+        lutex = lutex->next;
     }
+}
 
-    /* next vector */
-    {
-        lispobj next_vector_obj = hash_table->next_vector;
-
-        if (is_lisp_pointer(next_vector_obj) &&
-            (widetag_of(*(lispobj *)native_pointer(next_vector_obj)) ==
-             SIMPLE_ARRAY_WORD_WIDETAG)) {
-            next_vector = ((unsigned long *)native_pointer(next_vector_obj)) + 2;
-            /*FSHOW((stderr, "/next_vector = %x\n", next_vector));*/
-            next_vector_length = fixnum_value(((lispobj *)native_pointer(next_vector_obj))[1]);
-            /*FSHOW((stderr, "/next_vector_length = %d\n", next_vector_length));*/
-        } else {
-            lose("invalid next_vector %x", next_vector_obj);
+/*
+ * Finalize all lutexes in generation GEN that have not been marked live.
+ */
+static void
+reap_lutexes (generation_index_t gen) {
+    struct lutex *lutex = generations[gen].lutexes;
+
+    while (lutex) {
+        struct lutex *next = lutex->next;
+        if (!lutex->live) {
+            lutex_destroy(lutex);
+            gencgc_unregister_lutex(lutex);
         }
+        lutex = next;
     }
+}
 
-    /* maybe hash vector */
-    {
-        lispobj hash_vector_obj = hash_table->hash_vector;
-
-        if (is_lisp_pointer(hash_vector_obj) &&
-            (widetag_of(*(lispobj *)native_pointer(hash_vector_obj)) ==
-             SIMPLE_ARRAY_WORD_WIDETAG)){
-            hash_vector =
-                ((unsigned long *)native_pointer(hash_vector_obj)) + 2;
-            /*FSHOW((stderr, "/hash_vector = %x\n", hash_vector));*/
-            gc_assert(fixnum_value(((lispobj *)native_pointer(hash_vector_obj))[1])
-                      == next_vector_length);
-        } else {
-            hash_vector = NULL;
-            /*FSHOW((stderr, "/no hash_vector: %x\n", hash_vector_obj));*/
-        }
+/*
+ * Mark LUTEX as live.
+ */
+static void
+mark_lutex (lispobj tagged_lutex) {
+    struct lutex *lutex = (struct lutex*) native_pointer(tagged_lutex);
+
+    lutex->live = 1;
+}
+
+/*
+ * Move all lutexes in generation FROM to generation TO.
+ */
+static void
+move_lutexes (generation_index_t from, generation_index_t to) {
+    struct lutex *tail = generations[from].lutexes;
+
+    /* Nothing to move */
+    if (!tail)
+        return;
+
+    /* Change the generation of the lutexes in FROM. */
+    while (tail->next) {
+        tail->gen = to;
+        tail = tail->next;
     }
+    tail->gen = to;
 
-    /* These lengths could be different as the index_vector can be a
-     * different length from the others, a larger index_vector could help
-     * reduce collisions. */
-    gc_assert(next_vector_length*2 == kv_length);
+    /* Link the last lutex in the FROM list to the start of the TO list */
+    tail->next = generations[to].lutexes;
 
-    /* now all set up.. */
+    /* And vice versa */
+    if (generations[to].lutexes) {
+        generations[to].lutexes->prev = tail;
+    }
 
-    /* Work through the KV vector. */
-    {
-        long i;
-        for (i = 1; i < next_vector_length; i++) {
-            lispobj old_key = kv_vector[2*i];
+    /* And update the generations structures to match this */
+    generations[to].lutexes = generations[from].lutexes;
+    generations[from].lutexes = NULL;
+}
 
-#if N_WORD_BITS == 32
-            unsigned long old_index = (old_key & 0x1fffffff)%length;
-#elif N_WORD_BITS == 64
-            unsigned long old_index = (old_key & 0x1fffffffffffffff)%length;
-#endif
+static long
+scav_lutex(lispobj *where, lispobj object)
+{
+    mark_lutex((lispobj) where);
 
-            /* Scavenge the key and value. */
-            scavenge(&kv_vector[2*i],2);
+    return CEILING(sizeof(struct lutex)/sizeof(lispobj), 2);
+}
 
-            /* Check whether the key has moved and is EQ based. */
-            {
-                lispobj new_key = kv_vector[2*i];
-#if N_WORD_BITS == 32
-                unsigned long new_index = (new_key & 0x1fffffff)%length;
-#elif N_WORD_BITS == 64
-                unsigned long new_index = (new_key & 0x1fffffffffffffff)%length;
-#endif
+static lispobj
+trans_lutex(lispobj object)
+{
+    struct lutex *lutex = native_pointer(object);
+    lispobj copied;
+    size_t words = CEILING(sizeof(struct lutex)/sizeof(lispobj), 2);
+    gc_assert(is_lisp_pointer(object));
+    copied = copy_object(object, words);
 
-                if ((old_index != new_index) &&
-                    ((!hash_vector) ||
-                     (hash_vector[i] == MAGIC_HASH_VECTOR_VALUE)) &&
-                    ((new_key != empty_symbol) ||
-                     (kv_vector[2*i] != empty_symbol))) {
-
-                     /*FSHOW((stderr,
-                            "* EQ key %d moved from %x to %x; index %d to %d\n",
-                            i, old_key, new_key, old_index, new_index));*/
-
-                    if (index_vector[old_index] != 0) {
-                         /*FSHOW((stderr, "/P1 %d\n", index_vector[old_index]));*/
-
-                        /* Unlink the key from the old_index chain. */
-                        if (index_vector[old_index] == i) {
-                            /*FSHOW((stderr, "/P2a %d\n", next_vector[i]));*/
-                            index_vector[old_index] = next_vector[i];
-                            /* Link it into the needing rehash chain. */
-                            next_vector[i] = fixnum_value(hash_table->needing_rehash);
-                            hash_table->needing_rehash = make_fixnum(i);
-                            /*SHOW("P2");*/
-                        } else {
-                            unsigned long prior = index_vector[old_index];
-                            unsigned long next = next_vector[prior];
-
-                            /*FSHOW((stderr, "/P3a %d %d\n", prior, next));*/
-
-                            while (next != 0) {
-                                 /*FSHOW((stderr, "/P3b %d %d\n", prior, next));*/
-                                if (next == i) {
-                                    /* Unlink it. */
-                                    next_vector[prior] = next_vector[next];
-                                    /* Link it into the needing rehash
-                                     * chain. */
-                                    next_vector[next] =
-                                        fixnum_value(hash_table->needing_rehash);
-                                    hash_table->needing_rehash = make_fixnum(next);
-                                    /*SHOW("/P3");*/
-                                    break;
-                                }
-                                prior = next;
-                                next = next_vector[next];
-                            }
-                        }
-                    }
-                }
-            }
-        }
+    /* Update the links, since the lutex moved in memory. */
+    if (lutex->next) {
+        lutex->next->prev = native_pointer(copied);
     }
-    return (CEILING(kv_length + 2, 2));
+
+    if (lutex->prev) {
+        lutex->prev->next = native_pointer(copied);
+    } else {
+        generations[lutex->gen].lutexes = native_pointer(copied);
+    }
+
+    return copied;
 }
 
+static long
+size_lutex(lispobj *where)
+{
+    return CEILING(sizeof(struct lutex)/sizeof(lispobj), 2);
+}
+#endif /* LUTEX_WIDETAG */
 
 \f
 /*
@@ -2278,6 +2361,9 @@ possibly_valid_dynamic_space_pointer(lispobj *pointer)
 #endif
         case SAP_WIDETAG:
         case WEAK_POINTER_WIDETAG:
+#ifdef LUTEX_WIDETAG
+        case LUTEX_WIDETAG:
+#endif
             break;
 
         default:
@@ -2300,6 +2386,8 @@ possibly_valid_dynamic_space_pointer(lispobj *pointer)
     return 1;
 }
 
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
+
 /* Adjust large bignum and vector objects. This will adjust the
  * allocated region if the size has shrunk, and move unboxed objects
  * into unboxed pages. The pages are not promoted here, and the
@@ -2474,6 +2562,8 @@ maybe_adjust_large_object(lispobj *where)
     return;
 }
 
+#endif
+
 /* Take a possible pointer to a Lisp object and mark its page in the
  * page_table so that it will not be relocated during a GC.
  *
@@ -2486,6 +2576,9 @@ maybe_adjust_large_object(lispobj *where)
  *
  * It is also assumed that the current gc_alloc() region has been
  * flushed and the tables updated. */
+
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
+
 static void
 preserve_pointer(void *addr)
 {
@@ -2601,6 +2694,9 @@ preserve_pointer(void *addr)
     /* Check that the page is now static. */
     gc_assert(page_table[addr_page_index].dont_move != 0);
 }
+
+#endif
+
 \f
 /* If the given page is not write-protected, then scan it for pointers
  * to younger generations or the top temp. generation, if no
@@ -2754,15 +2850,15 @@ scavenge_generations(generation_index_t from, generation_index_t to)
                         num_wp += update_page_write_prot(j);
                     }
                 }
+                if ((gencgc_verbose > 1) && (num_wp != 0)) {
+                    FSHOW((stderr,
+                           "/write protected %d pages within generation %d\n",
+                           num_wp, generation));
+                }
             }
             i = last_page;
         }
     }
-    if ((gencgc_verbose > 1) && (num_wp != 0)) {
-        FSHOW((stderr,
-               "/write protected %d pages within generation %d\n",
-               num_wp, generation));
-    }
 
 #if SC_GEN_CK
     /* Check that none of the write_protected pages in this generation
@@ -2778,7 +2874,7 @@ scavenge_generations(generation_index_t from, generation_index_t to)
                     page_table[i].bytes_used,
                     page_table[i].first_object_offset,
                     page_table[i].dont_move));
-            lose("write to protected page %d in scavenge_generation()", i);
+            lose("write to protected page %d in scavenge_generation()\n", i);
         }
     }
 #endif
@@ -2910,6 +3006,13 @@ scavenge_newspace_generation(generation_index_t generation)
     /* Record all new areas now. */
     record_new_objects = 2;
 
+    /* Give a chance to weak hash tables to make other objects live.
+     * FIXME: The algorithm implemented here for weak hash table gcing
+     * is O(W^2+N) as Bruno Haible warns in
+     * http://www.haible.de/bruno/papers/cs/weak/WeakDatastructures-writeup.html
+     * see "Implementation 2". */
+    scav_weak_hash_tables();
+
     /* Flush the current regions updating the tables. */
     gc_alloc_update_all_page_tables();
 
@@ -2948,8 +3051,8 @@ scavenge_newspace_generation(generation_index_t generation)
             if (gencgc_verbose)
                 SHOW("new_areas overflow, doing full scavenge");
 
-            /* Don't need to record new areas that get scavenge anyway
-             * during scavenge_newspace_generation_one_scan. */
+            /* Don't need to record new areas that get scavenged
+             * anyway during scavenge_newspace_generation_one_scan. */
             record_new_objects = 1;
 
             scavenge_newspace_generation_one_scan(generation);
@@ -2957,6 +3060,8 @@ scavenge_newspace_generation(generation_index_t generation)
             /* Record all new areas now. */
             record_new_objects = 2;
 
+            scav_weak_hash_tables();
+
             /* Flush the current regions updating the tables. */
             gc_alloc_update_all_page_tables();
 
@@ -2971,6 +3076,8 @@ scavenge_newspace_generation(generation_index_t generation)
                 scavenge(page_address(page)+offset, size);
             }
 
+            scav_weak_hash_tables();
+
             /* Flush the current regions updating the tables. */
             gc_alloc_update_all_page_tables();
         }
@@ -2994,7 +3101,7 @@ scavenge_newspace_generation(generation_index_t generation)
             && (page_table[i].gen == generation)
             && (page_table[i].write_protected_cleared != 0)
             && (page_table[i].dont_move == 0)) {
-            lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d",
+            lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d\n",
                  i, generation, page_table[i].dont_move);
         }
     }
@@ -3080,31 +3187,12 @@ free_oldspace(void)
                && (page_table[last_page].bytes_used != 0)
                && (page_table[last_page].gen == from_space));
 
-        /* Zero pages from first_page to (last_page-1).
-         *
-         * FIXME: Why not use os_zero(..) function instead of
-         * hand-coding this again? (Check other gencgc_unmap_zero
-         * stuff too. */
-        if (gencgc_unmap_zero) {
-            void *page_start, *addr;
-
-            page_start = (void *)page_address(first_page);
-
-            os_invalidate(page_start, PAGE_BYTES*(last_page-first_page));
-            addr = os_validate(page_start, PAGE_BYTES*(last_page-first_page));
-            if (addr == NULL || addr != page_start) {
-                lose("free_oldspace: page moved, 0x%08x ==> 0x%08x",page_start,
-                     addr);
-            }
-        } else {
-            long *page_start;
-
-            page_start = (long *)page_address(first_page);
-            memset(page_start, 0,PAGE_BYTES*(last_page-first_page));
-        }
-
+#ifdef READ_PROTECT_FREE_PAGES
+        os_protect(page_address(first_page),
+                   PAGE_BYTES*(last_page-first_page),
+                   OS_VM_PROT_NONE);
+#endif
         first_page = last_page;
-
     } while (first_page < last_free_page);
 
     bytes_allocated -= bytes_freed;
@@ -3141,8 +3229,6 @@ print_ptr(lispobj *addr)
 }
 #endif
 
-extern long undefined_tramp;
-
 static void
 verify_space(lispobj *start, size_t words)
 {
@@ -3170,15 +3256,15 @@ verify_space(lispobj *start, size_t words)
                  * page. XX Could check the offset too. */
                 if ((page_table[page_index].allocated != FREE_PAGE_FLAG)
                     && (page_table[page_index].bytes_used == 0))
-                    lose ("Ptr %x @ %x sees free page.", thing, start);
+                    lose ("Ptr %x @ %x sees free page.\n", thing, start);
                 /* Check that it doesn't point to a forwarding pointer! */
                 if (*((lispobj *)native_pointer(thing)) == 0x01) {
-                    lose("Ptr %x @ %x sees forwarding ptr.", thing, start);
+                    lose("Ptr %x @ %x sees forwarding ptr.\n", thing, start);
                 }
                 /* Check that its not in the RO space as it would then be a
                  * pointer from the RO to the dynamic space. */
                 if (is_in_readonly_space) {
-                    lose("ptr to dynamic space %x from RO space %x",
+                    lose("ptr to dynamic space %x from RO space %x\n",
                          thing, start);
                 }
                 /* Does it point to a plausible object? This check slows
@@ -3192,14 +3278,13 @@ verify_space(lispobj *start, size_t words)
                  * dynamically. */
                 /*
                 if (!possibly_valid_dynamic_space_pointer((lispobj *)thing)) {
-                    lose("ptr %x to invalid object %x", thing, start);
+                    lose("ptr %x to invalid object %x\n", thing, start);
                 }
                 */
             } else {
                 /* Verify that it points to another valid space. */
-                if (!to_readonly_space && !to_static_space
-                    && (thing != (unsigned long)&undefined_tramp)) {
-                    lose("Ptr %x @ %x sees junk.", thing, start);
+                if (!to_readonly_space && !to_static_space) {
+                    lose("Ptr %x @ %x sees junk.\n", thing, start);
                 }
             }
         } else {
@@ -3229,11 +3314,24 @@ verify_space(lispobj *start, size_t words)
                 case SINGLE_FLOAT_WIDETAG:
 #endif
                 case UNBOUND_MARKER_WIDETAG:
-                case INSTANCE_HEADER_WIDETAG:
                 case FDEFN_WIDETAG:
                     count = 1;
                     break;
 
+                case INSTANCE_HEADER_WIDETAG:
+                    {
+                        lispobj nuntagged;
+                        long ntotal = HeaderValue(thing);
+                        lispobj layout = ((struct instance *)start)->slots[0];
+                        if (!layout) {
+                            count = 1;
+                            break;
+                        }
+                        nuntagged = ((struct layout *)native_pointer(layout))->n_untagged_slots;
+                        verify_space(start + 1, ntotal - fixnum_value(nuntagged));
+                        count = ntotal + 1;
+                        break;
+                    }
                 case CODE_HEADER_WIDETAG:
                     {
                         lispobj object = *start;
@@ -3366,10 +3464,17 @@ verify_space(lispobj *start, size_t words)
 #endif
                 case SAP_WIDETAG:
                 case WEAK_POINTER_WIDETAG:
+#ifdef LUTEX_WIDETAG
+                case LUTEX_WIDETAG:
+#endif
                     count = (sizetab[widetag_of(*start)])(start);
                     break;
 
                 default:
+                    FSHOW((stderr,
+                           "/Unhandled widetag 0x%x at 0x%x\n",
+                           widetag_of(*start), start));
+                    fflush(stderr);
                     gc_abort();
                 }
             }
@@ -3397,7 +3502,7 @@ verify_gc(void)
     struct thread *th;
     for_each_thread(th) {
     long binding_stack_size =
-            (lispobj*)SymbolValue(BINDING_STACK_POINTER,th)
+        (lispobj*)get_binding_stack_pointer(th)
             - (lispobj*)th->binding_stack_start;
         verify_space(th->binding_stack_start, binding_stack_size);
     }
@@ -3457,7 +3562,7 @@ verify_zero_fill(void)
             long i;
             for (i = 0; i < size; i++) {
                 if (start_addr[i] != 0) {
-                    lose("free page not zero at %x", start_addr + i);
+                    lose("free page not zero at %x\n", start_addr + i);
                 }
             }
         } else {
@@ -3469,7 +3574,7 @@ verify_zero_fill(void)
                 long i;
                 for (i = 0; i < size; i++) {
                     if (start_addr[i] != 0) {
-                        lose("free region not zero at %x", start_addr + i);
+                        lose("free region not zero at %x\n", start_addr + i);
                     }
                 }
             }
@@ -3546,6 +3651,186 @@ write_protect_generation_pages(generation_index_t generation)
     }
 }
 
+#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
+
+static void
+scavenge_control_stack()
+{
+    unsigned long control_stack_size;
+
+    /* This is going to be a big problem when we try to port threads
+     * to PPC... CLH */
+    struct thread *th = arch_os_get_current_thread();
+    lispobj *control_stack =
+        (lispobj *)(th->control_stack_start);
+
+    control_stack_size = current_control_stack_pointer - control_stack;
+    scavenge(control_stack, control_stack_size);
+}
+
+/* Scavenging Interrupt Contexts */
+
+static int boxed_registers[] = BOXED_REGISTERS;
+
+static void
+scavenge_interrupt_context(os_context_t * context)
+{
+    int i;
+
+#ifdef reg_LIP
+    unsigned long lip;
+    unsigned long lip_offset;
+    int lip_register_pair;
+#endif
+    unsigned long pc_code_offset;
+
+#ifdef ARCH_HAS_LINK_REGISTER
+    unsigned long lr_code_offset;
+#endif
+#ifdef ARCH_HAS_NPC_REGISTER
+    unsigned long npc_code_offset;
+#endif
+
+#ifdef reg_LIP
+    /* Find the LIP's register pair and calculate it's offset */
+    /* before we scavenge the context. */
+
+    /*
+     * I (RLT) think this is trying to find the boxed register that is
+     * closest to the LIP address, without going past it.  Usually, it's
+     * reg_CODE or reg_LRA.  But sometimes, nothing can be found.
+     */
+    lip = *os_context_register_addr(context, reg_LIP);
+    lip_offset = 0x7FFFFFFF;
+    lip_register_pair = -1;
+    for (i = 0; i < (sizeof(boxed_registers) / sizeof(int)); i++) {
+        unsigned long reg;
+        long offset;
+        int index;
+
+        index = boxed_registers[i];
+        reg = *os_context_register_addr(context, index);
+        if ((reg & ~((1L<<N_LOWTAG_BITS)-1)) <= lip) {
+            offset = lip - reg;
+            if (offset < lip_offset) {
+                lip_offset = offset;
+                lip_register_pair = index;
+            }
+        }
+    }
+#endif /* reg_LIP */
+
+    /* Compute the PC's offset from the start of the CODE */
+    /* register. */
+    pc_code_offset = *os_context_pc_addr(context) - *os_context_register_addr(context, reg_CODE);
+#ifdef ARCH_HAS_NPC_REGISTER
+    npc_code_offset = *os_context_npc_addr(context) - *os_context_register_addr(context, reg_CODE);
+#endif /* ARCH_HAS_NPC_REGISTER */
+
+#ifdef ARCH_HAS_LINK_REGISTER
+    lr_code_offset =
+        *os_context_lr_addr(context) -
+        *os_context_register_addr(context, reg_CODE);
+#endif
+
+    /* Scanvenge all boxed registers in the context. */
+    for (i = 0; i < (sizeof(boxed_registers) / sizeof(int)); i++) {
+        int index;
+        lispobj foo;
+
+        index = boxed_registers[i];
+        foo = *os_context_register_addr(context, index);
+        scavenge(&foo, 1);
+        *os_context_register_addr(context, index) = foo;
+
+        scavenge((lispobj*) &(*os_context_register_addr(context, index)), 1);
+    }
+
+#ifdef reg_LIP
+    /* Fix the LIP */
+
+    /*
+     * But what happens if lip_register_pair is -1?  *os_context_register_addr on Solaris
+     * (see solaris_register_address in solaris-os.c) will return
+     * &context->uc_mcontext.gregs[2].  But gregs[2] is REG_nPC.  Is
+     * that what we really want?  My guess is that that is not what we
+     * want, so if lip_register_pair is -1, we don't touch reg_LIP at
+     * all.  But maybe it doesn't really matter if LIP is trashed?
+     */
+    if (lip_register_pair >= 0) {
+        *os_context_register_addr(context, reg_LIP) =
+            *os_context_register_addr(context, lip_register_pair) + lip_offset;
+    }
+#endif /* reg_LIP */
+
+    /* Fix the PC if it was in from space */
+    if (from_space_p(*os_context_pc_addr(context)))
+        *os_context_pc_addr(context) = *os_context_register_addr(context, reg_CODE) + pc_code_offset;
+
+#ifdef ARCH_HAS_LINK_REGISTER
+    /* Fix the LR ditto; important if we're being called from
+     * an assembly routine that expects to return using blr, otherwise
+     * harmless */
+    if (from_space_p(*os_context_lr_addr(context)))
+        *os_context_lr_addr(context) =
+            *os_context_register_addr(context, reg_CODE) + lr_code_offset;
+#endif
+
+#ifdef ARCH_HAS_NPC_REGISTER
+    if (from_space_p(*os_context_npc_addr(context)))
+        *os_context_npc_addr(context) = *os_context_register_addr(context, reg_CODE) + npc_code_offset;
+#endif /* ARCH_HAS_NPC_REGISTER */
+}
+
+void
+scavenge_interrupt_contexts(void)
+{
+    int i, index;
+    os_context_t *context;
+
+    struct thread *th=arch_os_get_current_thread();
+
+    index = fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,0));
+
+#if defined(DEBUG_PRINT_CONTEXT_INDEX)
+    printf("Number of active contexts: %d\n", index);
+#endif
+
+    for (i = 0; i < index; i++) {
+        context = th->interrupt_contexts[i];
+        scavenge_interrupt_context(context);
+    }
+}
+
+#endif
+
+#if defined(LISP_FEATURE_SB_THREAD)
+static void
+preserve_context_registers (os_context_t *c)
+{
+    void **ptr;
+    /* On Darwin the signal context isn't a contiguous block of memory,
+     * so just preserve_pointering its contents won't be sufficient.
+     */
+#if defined(LISP_FEATURE_DARWIN)
+#if defined LISP_FEATURE_X86
+    preserve_pointer((void*)*os_context_register_addr(c,reg_EAX));
+    preserve_pointer((void*)*os_context_register_addr(c,reg_ECX));
+    preserve_pointer((void*)*os_context_register_addr(c,reg_EDX));
+    preserve_pointer((void*)*os_context_register_addr(c,reg_EBX));
+    preserve_pointer((void*)*os_context_register_addr(c,reg_ESI));
+    preserve_pointer((void*)*os_context_register_addr(c,reg_EDI));
+    preserve_pointer((void*)*os_context_pc_addr(c));
+#else
+    #error "preserve_context_registers needs to be tweaked for non-x86 Darwin"
+#endif
+#endif
+    for(ptr = ((void **)(c+1))-1; ptr>=(void **)c; ptr--) {
+        preserve_pointer(*ptr);
+    }
+}
+#endif
+
 /* Garbage collect a generation. If raise is 0 then the remains of the
  * generation are not raised to the next generation. */
 static void
@@ -3560,9 +3845,16 @@ garbage_collect_generation(generation_index_t generation, int raise)
     /* The oldest generation can't be raised. */
     gc_assert((generation != HIGHEST_NORMAL_GENERATION) || (raise == 0));
 
+    /* Check if weak hash tables were processed in the previous GC. */
+    gc_assert(weak_hash_tables == NULL);
+
     /* Initialize the weak pointer list. */
     weak_pointers = NULL;
 
+#ifdef LUTEX_WIDETAG
+    unmark_lutexes(generation);
+#endif
+
     /* When a generation is not being raised it is transported to a
      * temporary generation (NUM_GENERATIONS), and lowered when
      * done. Set up this new generation. There should be no pages
@@ -3614,6 +3906,7 @@ garbage_collect_generation(generation_index_t generation, int raise)
      * initiates GC.  If you ever call GC from inside an altstack
      * handler, you will lose. */
 
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
     /* And if we're saving a core, there's no point in being conservative. */
     if (conservative_stack) {
         for_each_thread(th) {
@@ -3634,20 +3927,20 @@ garbage_collect_generation(generation_index_t generation, int raise)
                     if (esp1>=(void **)th->control_stack_start &&
                         esp1<(void **)th->control_stack_end) {
                         if(esp1<esp) esp=esp1;
-                        for(ptr = (void **)(c+1); ptr>=(void **)c; ptr--) {
-                            preserve_pointer(*ptr);
-                        }
+                        preserve_context_registers(c);
                     }
                 }
             }
 #else
             esp = (void **)((void *)&raise);
 #endif
-            for (ptr = (void **)th->control_stack_end; ptr > esp;  ptr--) {
+            for (ptr = ((void **)th->control_stack_end)-1; ptr > esp;  ptr--) {
                 preserve_pointer(*ptr);
             }
         }
     }
+#endif
+
 #ifdef QSHOW
     if (gencgc_verbose > 1) {
         long num_dont_move_pages = count_dont_move_pages();
@@ -3660,6 +3953,15 @@ garbage_collect_generation(generation_index_t generation, int raise)
 
     /* Scavenge all the rest of the roots. */
 
+#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
+    /*
+     * If not x86, we need to scavenge the interrupt context(s) and the
+     * control stack.
+     */
+    scavenge_interrupt_contexts();
+    scavenge_control_stack();
+#endif
+
     /* Scavenge the Lisp functions of the interrupt handlers, taking
      * care to avoid SIG_DFL and SIG_IGN. */
     for (i = 0; i < NSIG; i++) {
@@ -3673,7 +3975,7 @@ garbage_collect_generation(generation_index_t generation, int raise)
     {
         struct thread *th;
         for_each_thread(th) {
-            long len= (lispobj *)SymbolValue(BINDING_STACK_POINTER,th) -
+            long len= (lispobj *)get_binding_stack_pointer(th) -
                 th->binding_stack_start;
             scavenge((lispobj *) th->binding_stack_start,len);
 #ifdef LISP_FEATURE_SB_THREAD
@@ -3747,12 +4049,13 @@ garbage_collect_generation(generation_index_t generation, int raise)
         bytes_allocated = bytes_allocated - old_bytes_allocated;
 
         if (bytes_allocated != 0) {
-            lose("Rescan of new_space allocated %d more bytes.",
+            lose("Rescan of new_space allocated %d more bytes.\n",
                  bytes_allocated);
         }
     }
 #endif
 
+    scan_weak_hash_tables();
     scan_weak_pointers();
 
     /* Flush the current regions, updating the tables. */
@@ -3796,6 +4099,12 @@ garbage_collect_generation(generation_index_t generation, int raise)
         generations[generation].num_gc = 0;
     else
         ++generations[generation].num_gc;
+
+#ifdef LUTEX_WIDETAG
+    reap_lutexes(generation);
+    if (raise)
+        move_lutexes(generation, generation+1);
+#endif
 }
 
 /* Update last_free_page, then SymbolValue(ALLOCATION_POINTER). */
@@ -3811,11 +4120,44 @@ update_dynamic_space_free_pointer(void)
 
     last_free_page = last_page+1;
 
-    SetSymbolValue(ALLOCATION_POINTER,
-                   (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
+    set_alloc_pointer((lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES));
     return 0; /* dummy value: return something ... */
 }
 
+static void
+remap_free_pages (page_index_t from, page_index_t to)
+{
+    page_index_t first_page, last_page;
+
+    for (first_page = from; first_page <= to; first_page++) {
+        if (page_table[first_page].allocated != FREE_PAGE_FLAG ||
+            page_table[first_page].need_to_zero == 0) {
+            continue;
+        }
+
+        last_page = first_page + 1;
+        while (page_table[last_page].allocated == FREE_PAGE_FLAG &&
+               last_page < to &&
+               page_table[last_page].need_to_zero == 1) {
+            last_page++;
+        }
+
+        /* There's a mysterious Solaris/x86 problem with using mmap
+         * tricks for memory zeroing. See sbcl-devel thread
+         * "Re: patch: standalone executable redux".
+         */
+#if defined(LISP_FEATURE_SUNOS)
+        zero_pages(first_page, last_page-1);
+#else
+        zero_pages_with_mmap(first_page, last_page-1);
+#endif
+
+        first_page = last_page;
+    }
+}
+
+generation_index_t small_generation_limit = 1;
+
 /* GC all generations newer than last_gen, raising the objects in each
  * to the next older generation - we finish when all generations below
  * last_gen are empty.  Then if last_gen is due for a GC, or if
@@ -3824,16 +4166,20 @@ update_dynamic_space_free_pointer(void)
  *
  * We stop collecting at gencgc_oldest_gen_to_gc, even if this is less than
  * last_gen (oh, and note that by default it is NUM_GENERATIONS-1) */
-
 void
 collect_garbage(generation_index_t last_gen)
 {
     generation_index_t gen = 0, i;
     int raise;
     int gen_to_wp;
+    /* The largest value of last_free_page seen since the time
+     * remap_free_pages was called. */
+    static page_index_t high_water_mark = 0;
 
     FSHOW((stderr, "/entering collect_garbage(%d)\n", last_gen));
 
+    gc_active_p = 1;
+
     if (last_gen > HIGHEST_NORMAL_GENERATION+1) {
         FSHOW((stderr,
                "/collect_garbage: last_gen = %d, doing a level 0 GC\n",
@@ -3921,7 +4267,7 @@ collect_garbage(generation_index_t last_gen)
         /* Check that they are all empty. */
         for (i = 0; i < gen_to_wp; i++) {
             if (generations[i].bytes_allocated)
-                lose("trying to write-protect gen. %d when gen. %d nonempty",
+                lose("trying to write-protect gen. %d when gen. %d nonempty\n",
                      gen_to_wp, i);
         }
         write_protect_generation_pages(gen_to_wp);
@@ -3932,11 +4278,29 @@ collect_garbage(generation_index_t last_gen)
     gc_assert((boxed_region.free_pointer - boxed_region.start_addr) == 0);
     gc_alloc_generation = 0;
 
+    /* Save the high-water mark before updating last_free_page */
+    if (last_free_page > high_water_mark)
+        high_water_mark = last_free_page;
+
     update_dynamic_space_free_pointer();
+
     auto_gc_trigger = bytes_allocated + bytes_consed_between_gcs;
     if(gencgc_verbose)
         fprintf(stderr,"Next gc when %ld bytes have been consed\n",
                 auto_gc_trigger);
+
+    /* If we did a big GC (arbitrarily defined as gen > 1), release memory
+     * back to the OS.
+     */
+    if (gen > small_generation_limit) {
+        if (last_free_page > high_water_mark)
+            high_water_mark = last_free_page;
+        remap_free_pages(0, high_water_mark);
+        high_water_mark = 0;
+    }
+
+    gc_active_p = 0;
+
     SHOW("returning from collect_garbage");
 }
 
@@ -3966,6 +4330,7 @@ gc_free_heap(void)
             page_table[page].allocated = FREE_PAGE_FLAG;
             page_table[page].bytes_used = 0;
 
+#ifndef LISP_FEATURE_WIN32 /* Pages already zeroed on win32? Not sure about this change. */
             /* Zero the page. */
             page_start = (void *)page_address(page);
 
@@ -3976,10 +4341,13 @@ gc_free_heap(void)
             os_invalidate(page_start,PAGE_BYTES);
             addr = os_validate(page_start,PAGE_BYTES);
             if (addr == NULL || addr != page_start) {
-                lose("gc_free_heap: page moved, 0x%08x ==> 0x%08x",
+                lose("gc_free_heap: page moved, 0x%08x ==> 0x%08x\n",
                      page_start,
                      addr);
             }
+#else
+            page_table[page].write_protected = 0;
+#endif
         } else if (gencgc_zero_check_during_free_heap) {
             /* Double-check that the page is zero filled. */
             long *page_start;
@@ -3989,7 +4357,7 @@ gc_free_heap(void)
             page_start = (long *)page_address(page);
             for (i=0; i<1024; i++) {
                 if (page_start[i] != 0) {
-                    lose("free region not zero at %x", page_start + i);
+                    lose("free region not zero at %x\n", page_start + i);
                 }
             }
         }
@@ -4007,6 +4375,7 @@ gc_free_heap(void)
         generations[page].gc_trigger = 2000000;
         generations[page].num_gc = 0;
         generations[page].cum_sum_bytes_allocated = 0;
+        generations[page].lutexes = NULL;
     }
 
     if (gencgc_verbose > 1)
@@ -4019,7 +4388,7 @@ gc_free_heap(void)
     gc_set_region_empty(&unboxed_region);
 
     last_free_page = 0;
-    SetSymbolValue(ALLOCATION_POINTER, (lispobj)((char *)heap_base),0);
+    set_alloc_pointer((lispobj)((char *)heap_base));
 
     if (verify_after_free_heap) {
         /* Check whether purify has left any bad pointers. */
@@ -4035,10 +4404,15 @@ gc_init(void)
     page_index_t i;
 
     gc_init_tables();
-    scavtab[SIMPLE_VECTOR_WIDETAG] = scav_vector;
     scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
     transother[SIMPLE_ARRAY_WIDETAG] = trans_boxed_large;
 
+#ifdef LUTEX_WIDETAG
+    scavtab[LUTEX_WIDETAG] = scav_lutex;
+    transother[LUTEX_WIDETAG] = trans_lutex;
+    sizetab[LUTEX_WIDETAG] = size_lutex;
+#endif
+
     heap_base = (void*)DYNAMIC_SPACE_START;
 
     /* Initialize each page structure. */
@@ -4069,6 +4443,7 @@ gc_init(void)
         generations[i].bytes_consed_between_gc = 2000000;
         generations[i].trigger_age = 1;
         generations[i].min_av_mem_age = 0.75;
+        generations[i].lutexes = NULL;
     }
 
     /* Initialize gc_alloc. */
@@ -4088,7 +4463,7 @@ static void
 gencgc_pickup_dynamic(void)
 {
     page_index_t page = 0;
-    long alloc_ptr = SymbolValue(ALLOCATION_POINTER,0);
+    long alloc_ptr = get_alloc_pointer();
     lispobj *prev=(lispobj *)page_address(page);
     generation_index_t gen = PSEUDO_STATIC_GENERATION;
 
@@ -4101,6 +4476,7 @@ gencgc_pickup_dynamic(void)
         page_table[page].write_protected = 0;
         page_table[page].write_protected_cleared = 0;
         page_table[page].dont_move = 0;
+        page_table[page].need_to_zero = 1;
 
         if (!gencgc_partial_pickup) {
             first=gc_search_space(prev,(ptr+2)-prev,ptr);
@@ -4111,6 +4487,13 @@ gencgc_pickup_dynamic(void)
         page++;
     } while ((long)page_address(page) < alloc_ptr);
 
+#ifdef LUTEX_WIDETAG
+    /* Lutexes have been registered in generation 0 by coreparse, and
+     * need to be moved to the right one manually.
+     */
+    move_lutexes(0, PSEUDO_STATIC_GENERATION);
+#endif
+
     last_free_page = page;
 
     generations[gen].bytes_allocated = PAGE_BYTES*page;
@@ -4154,16 +4537,18 @@ alloc(long nbytes)
     void *new_obj;
     void *new_free_pointer;
     gc_assert(nbytes>0);
+
     /* Check for alignment allocation problems. */
     gc_assert((((unsigned long)region->free_pointer & LOWTAG_MASK) == 0)
               && ((nbytes & LOWTAG_MASK) == 0));
+
 #if 0
     if(all_threads)
         /* there are a few places in the C code that allocate data in the
          * heap before Lisp starts.  This is before interrupts are enabled,
          * so we don't need to check for pseudo-atomic */
 #ifdef LISP_FEATURE_SB_THREAD
-        if(!SymbolValue(PSEUDO_ATOMIC_ATOMIC,th)) {
+        if(!get_psuedo_atomic_atomic(th)) {
             register u32 fs;
             fprintf(stderr, "fatal error in thread 0x%x, tid=%ld\n",
                     th,th->os_thread);
@@ -4173,7 +4558,7 @@ alloc(long nbytes)
             lose("If you see this message before 2004.01.31, mail details to sbcl-devel\n");
         }
 #else
-    gc_assert(SymbolValue(PSEUDO_ATOMIC_ATOMIC,th));
+    gc_assert(get_pseudo_atomic_atomic(th));
 #endif
 #endif
 
@@ -4189,7 +4574,7 @@ alloc(long nbytes)
      * we should GC in the near future
      */
     if (auto_gc_trigger && bytes_allocated > auto_gc_trigger) {
-        gc_assert(fixnum_value(SymbolValue(PSEUDO_ATOMIC_ATOMIC,thread)));
+        gc_assert(get_pseudo_atomic_atomic(thread));
         /* Don't flood the system with interrupts if the need to gc is
          * already noted. This can happen for example when SUB-GC
          * allocates or after a gc triggered in a WITHOUT-GCING. */
@@ -4198,7 +4583,7 @@ alloc(long nbytes)
              * section */
             SetSymbolValue(GC_PENDING,T,thread);
             if (SymbolValue(GC_INHIBIT,thread) == NIL)
-                arch_set_pseudo_atomic_interrupted(0);
+              set_pseudo_atomic_interrupted(thread);
         }
     }
     new_obj = gc_alloc_with_region(nbytes,0,region,0);
@@ -4256,7 +4641,8 @@ gencgc_handle_wp_violation(void* fault_addr)
              * does this test after the first one has already set wp=0
              */
             if(page_table[page_index].write_protected_cleared != 1)
-                lose("fault in heap page not marked as write-protected");
+                lose("fault in heap page %d not marked as write-protected\nboxed_region.first_page: %d, boxed_region.last_page %d\n",
+                     page_index, boxed_region.first_page, boxed_region.last_page);
         }
         /* Don't worry, we can handle it. */
         return 1;
@@ -4290,6 +4676,23 @@ gc_set_region_empty(struct alloc_region *region)
     region->end_addr = page_address(0);
 }
 
+static void
+zero_all_free_pages()
+{
+    page_index_t i;
+
+    for (i = 0; i < last_free_page; i++) {
+        if (page_table[i].allocated == FREE_PAGE_FLAG) {
+#ifdef READ_PROTECT_FREE_PAGES
+            os_protect(page_address(i),
+                       PAGE_BYTES,
+                       OS_VM_PROT_ALL);
+#endif
+            zero_pages(i, i);
+        }
+    }
+}
+
 /* Things to do before doing a final GC before saving a core (without
  * purify).
  *
@@ -4319,13 +4722,17 @@ prepare_for_final_gc ()
  * function being set to the value of the static symbol
  * SB!VM:RESTART-LISP-FUNCTION */
 void
-gc_and_save(char *filename)
+gc_and_save(char *filename, int prepend_runtime)
 {
-    FILE *file = open_core_for_saving(filename);
-    if (!file) {
-        perror(filename);
-        return;
-    }
+    FILE *file;
+    void *runtime_bytes = NULL;
+    size_t runtime_size;
+
+    file = prepare_to_save(filename, prepend_runtime, &runtime_bytes,
+                           &runtime_size);
+    if (file == NULL)
+       return;
+
     conservative_stack = 0;
 
     /* The filename might come from Lisp, and be moved by the now
@@ -4344,10 +4751,16 @@ gc_and_save(char *filename)
     gencgc_alloc_start_page = -1;
     collect_garbage(HIGHEST_NORMAL_GENERATION+1);
 
-    save_to_filehandle(file, filename, SymbolValue(RESTART_LISP_FUNCTION,0));
+    if (prepend_runtime)
+        save_runtime_to_filehandle(file, runtime_bytes, runtime_size);
+
+    /* The dumper doesn't know that pages need to be zeroed before use. */
+    zero_all_free_pages();
+    save_to_filehandle(file, filename, SymbolValue(RESTART_LISP_FUNCTION,0),
+                       prepend_runtime);
     /* Oops. Save still managed to fail. Since we've mangled the stack
      * beyond hope, there's not much we can do.
      * (beyond FUNCALLing RESTART_LISP_FUNCTION, but I suspect that's
      * going to be rather unsatisfactory too... */
-    lose("Attempt to save core after non-conservative GC failed.");
+    lose("Attempt to save core after non-conservative GC failed.\n");
 }