--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/ggc-zone.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,2525 @@
+/* "Bag-of-pages" zone garbage collector for the GNU compiler.
+   Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008
+   Free Software Foundation, Inc.
+
+   Contributed by Richard Henderson (rth@redhat.com) and Daniel Berlin
+   (dberlin@dberlin.org).  Rewritten by Daniel Jacobowitz
+   <dan@codesourcery.com>.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tree.h"
+#include "rtl.h"
+#include "tm_p.h"
+#include "toplev.h"
+#include "varray.h"
+#include "flags.h"
+#include "ggc.h"
+#include "timevar.h"
+#include "params.h"
+#include "bitmap.h"
+
+/* Prefer MAP_ANON(YMOUS) to /dev/zero, since we don't need to keep a
+   file open.  Prefer either to valloc.  */
+#ifdef HAVE_MMAP_ANON
+# undef HAVE_MMAP_DEV_ZERO
+
+# include <sys/mman.h>
+# ifndef MAP_FAILED
+#  define MAP_FAILED -1
+# endif
+# if !defined (MAP_ANONYMOUS) && defined (MAP_ANON)
+#  define MAP_ANONYMOUS MAP_ANON
+# endif
+# define USING_MMAP
+#endif
+
+#ifdef HAVE_MMAP_DEV_ZERO
+# include <sys/mman.h>
+# ifndef MAP_FAILED
+#  define MAP_FAILED -1
+# endif
+# define USING_MMAP
+#endif
+
+#ifndef USING_MMAP
+#error Zone collector requires mmap
+#endif
+
+#if (GCC_VERSION < 3001)
+#define prefetch(X) ((void) X)
+#define prefetchw(X) ((void) X)
+#else
+#define prefetch(X) __builtin_prefetch (X)
+#define prefetchw(X) __builtin_prefetch (X, 1, 3)
+#endif
+
+/* FUTURE NOTES:
+
+   If we track inter-zone pointers, we can mark single zones at a
+   time.
+
+   If we have a zone where we guarantee no inter-zone pointers, we
+   could mark that zone separately.
+
+   The garbage zone should not be marked, and we should return 1 in
+   ggc_set_mark for any object in the garbage zone, which cuts off
+   marking quickly.  */
+
+/* Strategy:
+
+   This garbage-collecting allocator segregates objects into zones.
+   It also segregates objects into "large" and "small" bins.  Large
+   objects are greater than page size.
+
+   Pages for small objects are broken up into chunks.  The page has
+   a bitmap which marks the start position of each chunk (whether
+   allocated or free).  Free chunks are on one of the zone's free
+   lists and contain a pointer to the next free chunk.  Chunks in
+   most of the free lists have a fixed size determined by the
+   free list.  Chunks in the "other" sized free list have their size
+   stored right after their chain pointer.
+
+   Empty pages (of all sizes) are kept on a single page cache list,
+   and are considered first when new pages are required; they are
+   deallocated at the start of the next collection if they haven't
+   been recycled by then.  The free page list is currently per-zone.  */
+
+/* Define GGC_DEBUG_LEVEL to print debugging information.
+     0: No debugging output.
+     1: GC statistics only.
+     2: Page-entry allocations/deallocations as well.
+     3: Object allocations as well.
+     4: Object marks as well.  */
+#define GGC_DEBUG_LEVEL (0)
+
+#ifndef HOST_BITS_PER_PTR
+#define HOST_BITS_PER_PTR  HOST_BITS_PER_LONG
+#endif
+
+/* This structure manages small free chunks.  The SIZE field is only
+   initialized if the chunk is in the "other" sized free list.  Large
+   chunks are allocated one at a time to their own page, and so don't
+   come in here.  */
+
+struct alloc_chunk {
+  struct alloc_chunk *next_free;
+  unsigned int size;
+};
+
+/* The size of the fixed-size portion of a small page descriptor.  */
+#define PAGE_OVERHEAD   (offsetof (struct small_page_entry, alloc_bits))
+
+/* The collector's idea of the page size.  This must be a power of two
+   no larger than the system page size, because pages must be aligned
+   to this amount and are tracked at this granularity in the page
+   table.  We choose a size at compile time for efficiency.
+
+   We could make a better guess at compile time if PAGE_SIZE is a
+   constant in system headers, and PAGE_SHIFT is defined...  */
+#define GGC_PAGE_SIZE	4096
+#define GGC_PAGE_MASK	(GGC_PAGE_SIZE - 1)
+#define GGC_PAGE_SHIFT	12
+
+#if 0
+/* Alternative definitions which use the runtime page size.  */
+#define GGC_PAGE_SIZE	G.pagesize
+#define GGC_PAGE_MASK	G.page_mask
+#define GGC_PAGE_SHIFT	G.lg_pagesize
+#endif
+
+/* The size of a small page managed by the garbage collector.  This
+   must currently be GGC_PAGE_SIZE, but with a few changes could
+   be any multiple of it to reduce certain kinds of overhead.  */
+#define SMALL_PAGE_SIZE GGC_PAGE_SIZE
+
+/* Free bin information.  These numbers may be in need of re-tuning.
+   In general, decreasing the number of free bins would seem to
+   increase the time it takes to allocate... */
+
+/* FIXME: We can't use anything but MAX_ALIGNMENT for the bin size
+   today.  */
+
+#define NUM_FREE_BINS		64
+#define FREE_BIN_DELTA		MAX_ALIGNMENT
+#define SIZE_BIN_DOWN(SIZE)	((SIZE) / FREE_BIN_DELTA)
+
+/* Allocation and marking parameters.  */
+
+/* The smallest allocatable unit to keep track of.  */
+#define BYTES_PER_ALLOC_BIT	MAX_ALIGNMENT
+
+/* The smallest markable unit.  If we require each allocated object
+   to contain at least two allocatable units, we can use half as many
+   bits for the mark bitmap.  But this adds considerable complexity
+   to sweeping.  */
+#define BYTES_PER_MARK_BIT	BYTES_PER_ALLOC_BIT
+
+#define BYTES_PER_MARK_WORD	(8 * BYTES_PER_MARK_BIT * sizeof (mark_type))
+
+/* We use this structure to determine the alignment required for
+   allocations.
+
+   There are several things wrong with this estimation of alignment.
+
+   The maximum alignment for a structure is often less than the
+   maximum alignment for a basic data type; for instance, on some
+   targets long long must be aligned to sizeof (int) in a structure
+   and sizeof (long long) in a variable.  i386-linux is one example;
+   Darwin is another (sometimes, depending on the compiler in use).
+
+   Also, long double is not included.  Nothing in GCC uses long
+   double, so we assume that this is OK.  On powerpc-darwin, adding
+   long double would bring the maximum alignment up to 16 bytes,
+   and until we need long double (or to vectorize compiler operations)
+   that's painfully wasteful.  This will need to change, some day.  */
+
+struct max_alignment {
+  char c;
+  union {
+    HOST_WIDEST_INT i;
+    double d;
+  } u;
+};
+
+/* The biggest alignment required.  */
+
+#define MAX_ALIGNMENT (offsetof (struct max_alignment, u))
+
+/* Compute the smallest multiple of F that is >= X.  */
+
+#define ROUND_UP(x, f) (CEIL (x, f) * (f))
+
+/* Types to use for the allocation and mark bitmaps.  It might be
+   a good idea to add ffsl to libiberty and use unsigned long
+   instead; that could speed us up where long is wider than int.  */
+
+typedef unsigned int alloc_type;
+typedef unsigned int mark_type;
+#define alloc_ffs(x) ffs(x)
+
+/* A page_entry records the status of an allocation page.  This is the
+   common data between all three kinds of pages - small, large, and
+   PCH.  */
+typedef struct page_entry
+{
+  /* The address at which the memory is allocated.  */
+  char *page;
+
+  /* The zone that this page entry belongs to.  */
+  struct alloc_zone *zone;
+
+#ifdef GATHER_STATISTICS
+  /* How many collections we've survived.  */
+  size_t survived;
+#endif
+
+  /* Does this page contain small objects, or one large object?  */
+  bool large_p;
+
+  /* Is this page part of the loaded PCH?  */
+  bool pch_p;
+} page_entry;
+
+/* Additional data needed for small pages.  */
+struct small_page_entry
+{
+  struct page_entry common;
+
+  /* The next small page entry, or NULL if this is the last.  */
+  struct small_page_entry *next;
+
+  /* If currently marking this zone, a pointer to the mark bits
+     for this page.  If we aren't currently marking this zone,
+     this pointer may be stale (pointing to freed memory).  */
+  mark_type *mark_bits;
+
+  /* The allocation bitmap.  This array extends far enough to have
+     one bit for every BYTES_PER_ALLOC_BIT bytes in the page.  */
+  alloc_type alloc_bits[1];
+};
+
+/* Additional data needed for large pages.  */
+struct large_page_entry
+{
+  struct page_entry common;
+
+  /* The next large page entry, or NULL if this is the last.  */
+  struct large_page_entry *next;
+
+  /* The number of bytes allocated, not including the page entry.  */
+  size_t bytes;
+
+  /* The previous page in the list, so that we can unlink this one.  */
+  struct large_page_entry *prev;
+
+  /* During marking, is this object marked?  */
+  bool mark_p;
+};
+
+/* A two-level tree is used to look up the page-entry for a given
+   pointer.  Two chunks of the pointer's bits are extracted to index
+   the first and second levels of the tree, as follows:
+
+				   HOST_PAGE_SIZE_BITS
+			   32		|      |
+       msb +----------------+----+------+------+ lsb
+			    |    |      |
+			 PAGE_L1_BITS   |
+				 |      |
+			       PAGE_L2_BITS
+
+   The bottommost HOST_PAGE_SIZE_BITS are ignored, since page-entry
+   pages are aligned on system page boundaries.  The next most
+   significant PAGE_L2_BITS and PAGE_L1_BITS are the second and first
+   index values in the lookup table, respectively.
+
+   For 32-bit architectures and the settings below, there are no
+   leftover bits.  For architectures with wider pointers, the lookup
+   tree points to a list of pages, which must be scanned to find the
+   correct one.  */
+
+#define PAGE_L1_BITS	(8)
+#define PAGE_L2_BITS	(32 - PAGE_L1_BITS - GGC_PAGE_SHIFT)
+#define PAGE_L1_SIZE	((size_t) 1 << PAGE_L1_BITS)
+#define PAGE_L2_SIZE	((size_t) 1 << PAGE_L2_BITS)
+
+#define LOOKUP_L1(p) \
+  (((size_t) (p) >> (32 - PAGE_L1_BITS)) & ((1 << PAGE_L1_BITS) - 1))
+
+#define LOOKUP_L2(p) \
+  (((size_t) (p) >> GGC_PAGE_SHIFT) & ((1 << PAGE_L2_BITS) - 1))
+
+#if HOST_BITS_PER_PTR <= 32
+
+/* On 32-bit hosts, we use a two level page table, as pictured above.  */
+typedef page_entry **page_table[PAGE_L1_SIZE];
+
+#else
+
+/* On 64-bit hosts, we use the same two level page tables plus a linked
+   list that disambiguates the top 32-bits.  There will almost always be
+   exactly one entry in the list.  */
+typedef struct page_table_chain
+{
+  struct page_table_chain *next;
+  size_t high_bits;
+  page_entry **table[PAGE_L1_SIZE];
+} *page_table;
+
+#endif
+
+/* The global variables.  */
+static struct globals
+{
+  /* The linked list of zones.  */
+  struct alloc_zone *zones;
+
+  /* Lookup table for associating allocation pages with object addresses.  */
+  page_table lookup;
+
+  /* The system's page size, and related constants.  */
+  size_t pagesize;
+  size_t lg_pagesize;
+  size_t page_mask;
+
+  /* The size to allocate for a small page entry.  This includes
+     the size of the structure and the size of the allocation
+     bitmap.  */
+  size_t small_page_overhead;
+
+#if defined (HAVE_MMAP_DEV_ZERO)
+  /* A file descriptor open to /dev/zero for reading.  */
+  int dev_zero_fd;
+#endif
+
+  /* Allocate pages in chunks of this size, to throttle calls to memory
+     allocation routines.  The first page is used, the rest go onto the
+     free list.  */
+  size_t quire_size;
+
+  /* The file descriptor for debugging output.  */
+  FILE *debug_file;
+} G;
+
+/* A zone allocation structure.  There is one of these for every
+   distinct allocation zone.  */
+struct alloc_zone
+{
+  /* The most recent free chunk is saved here, instead of in the linked
+     free list, to decrease list manipulation.  It is most likely that we
+     will want this one.  */
+  char *cached_free;
+  size_t cached_free_size;
+
+  /* Linked lists of free storage.  Slots 1 ... NUM_FREE_BINS have chunks of size
+     FREE_BIN_DELTA.  All other chunks are in slot 0.  */
+  struct alloc_chunk *free_chunks[NUM_FREE_BINS + 1];
+
+  /* The highest bin index which might be non-empty.  It may turn out
+     to be empty, in which case we have to search downwards.  */
+  size_t high_free_bin;
+
+  /* Bytes currently allocated in this zone.  */
+  size_t allocated;
+
+  /* Linked list of the small pages in this zone.  */
+  struct small_page_entry *pages;
+
+  /* Doubly linked list of large pages in this zone.  */
+  struct large_page_entry *large_pages;
+
+  /* If we are currently marking this zone, a pointer to the mark bits.  */
+  mark_type *mark_bits;
+
+  /* Name of the zone.  */
+  const char *name;
+
+  /* The number of small pages currently allocated in this zone.  */
+  size_t n_small_pages;
+
+  /* Bytes allocated at the end of the last collection.  */
+  size_t allocated_last_gc;
+
+  /* Total amount of memory mapped.  */
+  size_t bytes_mapped;
+
+  /* A cache of free system pages.  */
+  struct small_page_entry *free_pages;
+
+  /* Next zone in the linked list of zones.  */
+  struct alloc_zone *next_zone;
+
+  /* True if this zone was collected during this collection.  */
+  bool was_collected;
+
+  /* True if this zone should be destroyed after the next collection.  */
+  bool dead;
+
+#ifdef GATHER_STATISTICS
+  struct
+  {
+    /* Total memory allocated with ggc_alloc.  */
+    unsigned long long total_allocated;
+    /* Total overhead for memory to be allocated with ggc_alloc.  */
+    unsigned long long total_overhead;
+
+    /* Total allocations and overhead for sizes less than 32, 64 and 128.
+       These sizes are interesting because they are typical cache line
+       sizes.  */
+   
+    unsigned long long total_allocated_under32;
+    unsigned long long total_overhead_under32;
+  
+    unsigned long long total_allocated_under64;
+    unsigned long long total_overhead_under64;
+  
+    unsigned long long total_allocated_under128;
+    unsigned long long total_overhead_under128;
+  } stats;
+#endif
+} main_zone;
+
+/* Some default zones.  */
+struct alloc_zone rtl_zone;
+struct alloc_zone tree_zone;
+struct alloc_zone tree_id_zone;
+
+/* The PCH zone does not need a normal zone structure, and it does
+   not live on the linked list of zones.  */
+struct pch_zone
+{
+  /* The start of the PCH zone.  NULL if there is none.  */
+  char *page;
+
+  /* The end of the PCH zone.  NULL if there is none.  */
+  char *end;
+
+  /* The size of the PCH zone.  0 if there is none.  */
+  size_t bytes;
+
+  /* The allocation bitmap for the PCH zone.  */
+  alloc_type *alloc_bits;
+
+  /* If we are currently marking, the mark bitmap for the PCH zone.
+     When it is first read in, we could avoid marking the PCH,
+     because it will not contain any pointers to GC memory outside
+     of the PCH; however, the PCH is currently mapped as writable,
+     so we must mark it in case new pointers are added.  */
+  mark_type *mark_bits;
+} pch_zone;
+
+#ifdef USING_MMAP
+static char *alloc_anon (char *, size_t, struct alloc_zone *);
+#endif
+static struct small_page_entry * alloc_small_page (struct alloc_zone *);
+static struct large_page_entry * alloc_large_page (size_t, struct alloc_zone *);
+static void free_chunk (char *, size_t, struct alloc_zone *);
+static void free_small_page (struct small_page_entry *);
+static void free_large_page (struct large_page_entry *);
+static void release_pages (struct alloc_zone *);
+static void sweep_pages (struct alloc_zone *);
+static bool ggc_collect_1 (struct alloc_zone *, bool);
+static void new_ggc_zone_1 (struct alloc_zone *, const char *);
+
+/* Traverse the page table and find the entry for a page.
+   Die (probably) if the object wasn't allocated via GC.  */
+
+static inline page_entry *
+lookup_page_table_entry (const void *p)
+{
+  page_entry ***base;
+  size_t L1, L2;
+
+#if HOST_BITS_PER_PTR <= 32
+  base = &G.lookup[0];
+#else
+  page_table table = G.lookup;
+  size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
+  while (table->high_bits != high_bits)
+    table = table->next;
+  base = &table->table[0];
+#endif
+
+  /* Extract the level 1 and 2 indices.  */
+  L1 = LOOKUP_L1 (p);
+  L2 = LOOKUP_L2 (p);
+
+  return base[L1][L2];
+}
+
+/* Traverse the page table and find the entry for a page.
+   Return NULL if the object wasn't allocated via the GC.  */
+
+static inline page_entry *
+lookup_page_table_if_allocated (const void *p)
+{
+  page_entry ***base;
+  size_t L1, L2;
+
+#if HOST_BITS_PER_PTR <= 32
+  base = &G.lookup[0];
+#else
+  page_table table = G.lookup;
+  size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
+  while (1)
+    {
+      if (table == NULL)
+	return NULL;
+      if (table->high_bits == high_bits)
+	break;
+      table = table->next;
+    }
+  base = &table->table[0];
+#endif
+
+  /* Extract the level 1 and 2 indices.  */
+  L1 = LOOKUP_L1 (p);
+  if (! base[L1])
+    return NULL;
+
+  L2 = LOOKUP_L2 (p);
+  if (L2 >= PAGE_L2_SIZE)
+    return NULL;
+  /* We might have a page entry which does not correspond exactly to a
+     system page.  */
+  if (base[L1][L2] && (const char *) p < base[L1][L2]->page)
+    return NULL;
+
+  return base[L1][L2];
+}
+
+/* Set the page table entry for the page that starts at P.  If ENTRY
+   is NULL, clear the entry.  */
+
+static void
+set_page_table_entry (void *p, page_entry *entry)
+{
+  page_entry ***base;
+  size_t L1, L2;
+
+#if HOST_BITS_PER_PTR <= 32
+  base = &G.lookup[0];
+#else
+  page_table table;
+  size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
+  for (table = G.lookup; table; table = table->next)
+    if (table->high_bits == high_bits)
+      goto found;
+
+  /* Not found -- allocate a new table.  */
+  table = XCNEW (struct page_table_chain);
+  table->next = G.lookup;
+  table->high_bits = high_bits;
+  G.lookup = table;
+found:
+  base = &table->table[0];
+#endif
+
+  /* Extract the level 1 and 2 indices.  */
+  L1 = LOOKUP_L1 (p);
+  L2 = LOOKUP_L2 (p);
+
+  if (base[L1] == NULL)
+    base[L1] = XCNEWVEC (page_entry *, PAGE_L2_SIZE);
+
+  base[L1][L2] = entry;
+}
+
+/* Find the page table entry associated with OBJECT.  */
+
+static inline struct page_entry *
+zone_get_object_page (const void *object)
+{
+  return lookup_page_table_entry (object);
+}
+
+/* Find which element of the alloc_bits array OBJECT should be
+   recorded in.  */
+static inline unsigned int
+zone_get_object_alloc_word (const void *object)
+{
+  return (((size_t) object & (GGC_PAGE_SIZE - 1))
+	  / (8 * sizeof (alloc_type) * BYTES_PER_ALLOC_BIT));
+}
+
+/* Find which bit of the appropriate word in the alloc_bits array
+   OBJECT should be recorded in.  */
+static inline unsigned int
+zone_get_object_alloc_bit (const void *object)
+{
+  return (((size_t) object / BYTES_PER_ALLOC_BIT)
+	  % (8 * sizeof (alloc_type)));
+}
+
+/* Find which element of the mark_bits array OBJECT should be recorded
+   in.  */
+static inline unsigned int
+zone_get_object_mark_word (const void *object)
+{
+  return (((size_t) object & (GGC_PAGE_SIZE - 1))
+	  / (8 * sizeof (mark_type) * BYTES_PER_MARK_BIT));
+}
+
+/* Find which bit of the appropriate word in the mark_bits array
+   OBJECT should be recorded in.  */
+static inline unsigned int
+zone_get_object_mark_bit (const void *object)
+{
+  return (((size_t) object / BYTES_PER_MARK_BIT)
+	  % (8 * sizeof (mark_type)));
+}
+
+/* Set the allocation bit corresponding to OBJECT in its page's
+   bitmap.  Used to split this object from the preceding one.  */
+static inline void
+zone_set_object_alloc_bit (const void *object)
+{
+  struct small_page_entry *page
+    = (struct small_page_entry *) zone_get_object_page (object);
+  unsigned int start_word = zone_get_object_alloc_word (object);
+  unsigned int start_bit = zone_get_object_alloc_bit (object);
+
+  page->alloc_bits[start_word] |= 1L << start_bit;
+}
+
+/* Clear the allocation bit corresponding to OBJECT in PAGE's
+   bitmap.  Used to coalesce this object with the preceding
+   one.  */
+static inline void
+zone_clear_object_alloc_bit (struct small_page_entry *page,
+			     const void *object)
+{
+  unsigned int start_word = zone_get_object_alloc_word (object);
+  unsigned int start_bit = zone_get_object_alloc_bit (object);
+
+  /* Would xor be quicker?  */
+  page->alloc_bits[start_word] &= ~(1L << start_bit);
+}
+
+/* Find the size of the object which starts at START_WORD and
+   START_BIT in ALLOC_BITS, which is at most MAX_SIZE bytes.
+   Helper function for ggc_get_size and zone_find_object_size.  */
+
+static inline size_t
+zone_object_size_1 (alloc_type *alloc_bits,
+		    size_t start_word, size_t start_bit,
+		    size_t max_size)
+{
+  size_t size;
+  alloc_type alloc_word;
+  int indx;
+
+  /* Load the first word.  */
+  alloc_word = alloc_bits[start_word++];
+
+  /* If that was the last bit in this word, we'll want to continue
+     with the next word.  Otherwise, handle the rest of this word.  */
+  if (start_bit)
+    {
+      indx = alloc_ffs (alloc_word >> start_bit);
+      if (indx)
+	/* indx is 1-based.  We started at the bit after the object's
+	   start, but we also ended at the bit after the object's end.
+	   It cancels out.  */
+	return indx * BYTES_PER_ALLOC_BIT;
+
+      /* The extra 1 accounts for the starting unit, before start_bit.  */
+      size = (sizeof (alloc_type) * 8 - start_bit + 1) * BYTES_PER_ALLOC_BIT;
+
+      if (size >= max_size)
+	return max_size;
+
+      alloc_word = alloc_bits[start_word++];
+    }
+  else
+    size = BYTES_PER_ALLOC_BIT;
+
+  while (alloc_word == 0)
+    {
+      size += sizeof (alloc_type) * 8 * BYTES_PER_ALLOC_BIT;
+      if (size >= max_size)
+	return max_size;
+      alloc_word = alloc_bits[start_word++];
+    }
+
+  indx = alloc_ffs (alloc_word);
+  return size + (indx - 1) * BYTES_PER_ALLOC_BIT;
+}
+
+/* Find the size of OBJECT on small page PAGE.  */
+
+static inline size_t
+zone_find_object_size (struct small_page_entry *page,
+		       const void *object)
+{
+  const char *object_midptr = (const char *) object + BYTES_PER_ALLOC_BIT;
+  unsigned int start_word = zone_get_object_alloc_word (object_midptr);
+  unsigned int start_bit = zone_get_object_alloc_bit (object_midptr);
+  size_t max_size = (page->common.page + SMALL_PAGE_SIZE
+		     - (const char *) object);
+
+  return zone_object_size_1 (page->alloc_bits, start_word, start_bit,
+			     max_size);
+}
+
+/* highest_bit assumes that alloc_type is 32 bits.  */
+extern char check_alloc_type_size[(sizeof (alloc_type) == 4) ? 1 : -1];
+
+/* Find the highest set bit in VALUE.  Returns the bit number of that
+   bit, using the same values as ffs.  */
+static inline alloc_type
+highest_bit (alloc_type value)
+{
+  /* This also assumes that alloc_type is unsigned.  */
+  value |= value >> 1;
+  value |= value >> 2;
+  value |= value >> 4;
+  value |= value >> 8;
+  value |= value >> 16;
+  value = value ^ (value >> 1);
+  return alloc_ffs (value);
+}
+
+/* Find the offset from the start of an object to P, which may point
+   into the interior of the object.  */
+
+static unsigned long
+zone_find_object_offset (alloc_type *alloc_bits, size_t start_word,
+			 size_t start_bit)
+{
+  unsigned int offset_in_bits;
+  alloc_type alloc_word = alloc_bits[start_word];
+
+  /* Mask off any bits after the initial bit, but make sure to include
+     the initial bit in the result.  Note that START_BIT is
+     0-based.  */
+  if (start_bit < 8 * sizeof (alloc_type) - 1)
+    alloc_word &= (1 << (start_bit + 1)) - 1;
+  offset_in_bits = start_bit;
+
+  /* Search for the start of the object.  */
+  while (alloc_word == 0 && start_word > 0)
+    {
+      alloc_word = alloc_bits[--start_word];
+      offset_in_bits += 8 * sizeof (alloc_type);
+    }
+  /* We must always find a set bit.  */
+  gcc_assert (alloc_word != 0);
+  /* Note that the result of highest_bit is 1-based.  */
+  offset_in_bits -= highest_bit (alloc_word) - 1;
+
+  return BYTES_PER_ALLOC_BIT * offset_in_bits;
+}
+
+/* Allocate the mark bits for every zone, and set the pointers on each
+   page.  */
+static void
+zone_allocate_marks (void)
+{
+  struct alloc_zone *zone;
+
+  for (zone = G.zones; zone; zone = zone->next_zone)
+    {
+      struct small_page_entry *page;
+      mark_type *cur_marks;
+      size_t mark_words, mark_words_per_page;
+#ifdef ENABLE_CHECKING
+      size_t n = 0;
+#endif
+
+      mark_words_per_page
+	= (GGC_PAGE_SIZE + BYTES_PER_MARK_WORD - 1) / BYTES_PER_MARK_WORD;
+      mark_words = zone->n_small_pages * mark_words_per_page;
+      zone->mark_bits = (mark_type *) xcalloc (sizeof (mark_type),
+						   mark_words);
+      cur_marks = zone->mark_bits;
+      for (page = zone->pages; page; page = page->next)
+	{
+	  page->mark_bits = cur_marks;
+	  cur_marks += mark_words_per_page;
+#ifdef ENABLE_CHECKING
+	  n++;
+#endif
+	}
+#ifdef ENABLE_CHECKING
+      gcc_assert (n == zone->n_small_pages);
+#endif
+    }
+
+  /* We don't collect the PCH zone, but we do have to mark it
+     (for now).  */
+  if (pch_zone.bytes)
+    pch_zone.mark_bits
+      = (mark_type *) xcalloc (sizeof (mark_type),
+			       CEIL (pch_zone.bytes, BYTES_PER_MARK_WORD));
+}
+
+/* After marking and sweeping, release the memory used for mark bits.  */
+static void
+zone_free_marks (void)
+{
+  struct alloc_zone *zone;
+
+  for (zone = G.zones; zone; zone = zone->next_zone)
+    if (zone->mark_bits)
+      {
+	free (zone->mark_bits);
+	zone->mark_bits = NULL;
+      }
+
+  if (pch_zone.bytes)
+    {
+      free (pch_zone.mark_bits);
+      pch_zone.mark_bits = NULL;
+    }
+}
+
+#ifdef USING_MMAP
+/* Allocate SIZE bytes of anonymous memory, preferably near PREF,
+   (if non-null).  The ifdef structure here is intended to cause a
+   compile error unless exactly one of the HAVE_* is defined.  */
+
+static inline char *
+alloc_anon (char *pref ATTRIBUTE_UNUSED, size_t size, struct alloc_zone *zone)
+{
+#ifdef HAVE_MMAP_ANON
+  char *page = (char *) mmap (pref, size, PROT_READ | PROT_WRITE,
+			      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+#endif
+#ifdef HAVE_MMAP_DEV_ZERO
+  char *page = (char *) mmap (pref, size, PROT_READ | PROT_WRITE,
+			      MAP_PRIVATE, G.dev_zero_fd, 0);
+#endif
+
+  if (page == (char *) MAP_FAILED)
+    {
+      perror ("virtual memory exhausted");
+      exit (FATAL_EXIT_CODE);
+    }
+
+  /* Remember that we allocated this memory.  */
+  zone->bytes_mapped += size;
+
+  /* Pretend we don't have access to the allocated pages.  We'll enable
+     access to smaller pieces of the area in ggc_alloc.  Discard the
+     handle to avoid handle leak.  */
+  VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (page, size));
+
+  return page;
+}
+#endif
+
+/* Allocate a new page for allocating small objects in ZONE, and
+   return an entry for it.  */
+
+static struct small_page_entry *
+alloc_small_page (struct alloc_zone *zone)
+{
+  struct small_page_entry *entry;
+
+  /* Check the list of free pages for one we can use.  */
+  entry = zone->free_pages;
+  if (entry != NULL)
+    {
+      /* Recycle the allocated memory from this page ...  */
+      zone->free_pages = entry->next;
+    }
+  else
+    {
+      /* We want just one page.  Allocate a bunch of them and put the
+	 extras on the freelist.  (Can only do this optimization with
+	 mmap for backing store.)  */
+      struct small_page_entry *e, *f = zone->free_pages;
+      int i;
+      char *page;
+
+      page = alloc_anon (NULL, GGC_PAGE_SIZE * G.quire_size, zone);
+
+      /* This loop counts down so that the chain will be in ascending
+	 memory order.  */
+      for (i = G.quire_size - 1; i >= 1; i--)
+	{
+	  e = XCNEWVAR (struct small_page_entry, G.small_page_overhead);
+	  e->common.page = page + (i << GGC_PAGE_SHIFT);
+	  e->common.zone = zone;
+	  e->next = f;
+	  f = e;
+	  set_page_table_entry (e->common.page, &e->common);
+	}
+
+      zone->free_pages = f;
+
+      entry = XCNEWVAR (struct small_page_entry, G.small_page_overhead);
+      entry->common.page = page;
+      entry->common.zone = zone;
+      set_page_table_entry (page, &entry->common);
+    }
+
+  zone->n_small_pages++;
+
+  if (GGC_DEBUG_LEVEL >= 2)
+    fprintf (G.debug_file,
+	     "Allocating %s page at %p, data %p-%p\n",
+	     entry->common.zone->name, (PTR) entry, entry->common.page,
+	     entry->common.page + SMALL_PAGE_SIZE - 1);
+
+  return entry;
+}
+
+/* Allocate a large page of size SIZE in ZONE.  */
+
+static struct large_page_entry *
+alloc_large_page (size_t size, struct alloc_zone *zone)
+{
+  struct large_page_entry *entry;
+  char *page;
+  size_t needed_size;
+
+  needed_size = size + sizeof (struct large_page_entry);
+  page = XNEWVAR (char, needed_size);
+
+  entry = (struct large_page_entry *) page;
+
+  entry->next = NULL;
+  entry->common.page = page + sizeof (struct large_page_entry);
+  entry->common.large_p = true;
+  entry->common.pch_p = false;
+  entry->common.zone = zone;
+#ifdef GATHER_STATISTICS
+  entry->common.survived = 0;
+#endif
+  entry->mark_p = false;
+  entry->bytes = size;
+  entry->prev = NULL;
+
+  set_page_table_entry (entry->common.page, &entry->common);
+
+  if (GGC_DEBUG_LEVEL >= 2)
+    fprintf (G.debug_file,
+	     "Allocating %s large page at %p, data %p-%p\n",
+	     entry->common.zone->name, (PTR) entry, entry->common.page,
+	     entry->common.page + SMALL_PAGE_SIZE - 1);
+
+  return entry;
+}
+
+
+/* For a page that is no longer needed, put it on the free page list.  */
+
+static inline void
+free_small_page (struct small_page_entry *entry)
+{
+  if (GGC_DEBUG_LEVEL >= 2)
+    fprintf (G.debug_file,
+	     "Deallocating %s page at %p, data %p-%p\n",
+	     entry->common.zone->name, (PTR) entry,
+	     entry->common.page, entry->common.page + SMALL_PAGE_SIZE - 1);
+
+  gcc_assert (!entry->common.large_p);
+
+  /* Mark the page as inaccessible.  Discard the handle to
+     avoid handle leak.  */
+  VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (entry->common.page,
+						SMALL_PAGE_SIZE));
+
+  entry->next = entry->common.zone->free_pages;
+  entry->common.zone->free_pages = entry;
+  entry->common.zone->n_small_pages--;
+}
+
+/* Release a large page that is no longer needed.  */
+
+static inline void
+free_large_page (struct large_page_entry *entry)
+{
+  if (GGC_DEBUG_LEVEL >= 2)
+    fprintf (G.debug_file,
+	     "Deallocating %s page at %p, data %p-%p\n",
+	     entry->common.zone->name, (PTR) entry,
+	     entry->common.page, entry->common.page + SMALL_PAGE_SIZE - 1);
+
+  gcc_assert (entry->common.large_p);
+
+  set_page_table_entry (entry->common.page, NULL);
+  free (entry);
+}
+
+/* Release the free page cache to the system.  */
+
+static void
+release_pages (struct alloc_zone *zone)
+{
+#ifdef USING_MMAP
+  struct small_page_entry *p, *next;
+  char *start;
+  size_t len;
+
+  /* Gather up adjacent pages so they are unmapped together.  */
+  p = zone->free_pages;
+
+  while (p)
+    {
+      start = p->common.page;
+      next = p->next;
+      len = SMALL_PAGE_SIZE;
+      set_page_table_entry (p->common.page, NULL);
+      p = next;
+
+      while (p && p->common.page == start + len)
+	{
+	  next = p->next;
+	  len += SMALL_PAGE_SIZE;
+	  set_page_table_entry (p->common.page, NULL);
+	  p = next;
+	}
+
+      munmap (start, len);
+      zone->bytes_mapped -= len;
+    }
+
+  zone->free_pages = NULL;
+#endif
+}
+
+/* Place the block at PTR of size SIZE on the free list for ZONE.  */
+
+static inline void
+free_chunk (char *ptr, size_t size, struct alloc_zone *zone)
+{
+  struct alloc_chunk *chunk = (struct alloc_chunk *) ptr;
+  size_t bin = 0;
+
+  bin = SIZE_BIN_DOWN (size);
+  gcc_assert (bin != 0);
+  if (bin > NUM_FREE_BINS)
+    {
+      bin = 0;
+      VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (chunk,
+						     sizeof (struct
+							     alloc_chunk)));
+      chunk->size = size;
+      chunk->next_free = zone->free_chunks[bin];
+      VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (ptr
+						    + sizeof (struct
+							      alloc_chunk),
+						    size
+						    - sizeof (struct
+							      alloc_chunk)));
+    }
+  else
+    {
+      VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (chunk,
+						     sizeof (struct
+							     alloc_chunk *)));
+      chunk->next_free = zone->free_chunks[bin];
+      VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (ptr
+						    + sizeof (struct
+							      alloc_chunk *),
+						    size
+						    - sizeof (struct
+							      alloc_chunk *)));
+    }
+
+  zone->free_chunks[bin] = chunk;
+  if (bin > zone->high_free_bin)
+    zone->high_free_bin = bin;
+  if (GGC_DEBUG_LEVEL >= 3)
+    fprintf (G.debug_file, "Deallocating object, chunk=%p\n", (void *)chunk);
+}
+
+/* Allocate a chunk of memory of at least ORIG_SIZE bytes, in ZONE.  */
+
+void *
+ggc_alloc_zone_stat (size_t orig_size, struct alloc_zone *zone
+		     MEM_STAT_DECL)
+{
+  size_t bin;
+  size_t csize;
+  struct small_page_entry *entry;
+  struct alloc_chunk *chunk, **pp;
+  void *result;
+  size_t size = orig_size;
+
+  /* Make sure that zero-sized allocations get a unique and freeable
+     pointer.  */
+  if (size == 0)
+    size = MAX_ALIGNMENT;
+  else
+    size = (size + MAX_ALIGNMENT - 1) & -MAX_ALIGNMENT;
+
+  /* Try to allocate the object from several different sources.  Each
+     of these cases is responsible for setting RESULT and SIZE to
+     describe the allocated block, before jumping to FOUND.  If a
+     chunk is split, the allocate bit for the new chunk should also be
+     set.
+
+     Large objects are handled specially.  However, they'll just fail
+     the next couple of conditions, so we can wait to check for them
+     below.  The large object case is relatively rare (< 1%), so this
+     is a win.  */
+
+  /* First try to split the last chunk we allocated.  For best
+     fragmentation behavior it would be better to look for a
+     free bin of the appropriate size for a small object.  However,
+     we're unlikely (1% - 7%) to find one, and this gives better
+     locality behavior anyway.  This case handles the lion's share
+     of all calls to this function.  */
+  if (size <= zone->cached_free_size)
+    {
+      result = zone->cached_free;
+
+      zone->cached_free_size -= size;
+      if (zone->cached_free_size)
+	{
+	  zone->cached_free += size;
+	  zone_set_object_alloc_bit (zone->cached_free);
+	}
+
+      goto found;
+    }
+
+  /* Next, try to find a free bin of the exactly correct size.  */
+
+  /* We want to round SIZE up, rather than down, but we know it's
+     already aligned to at least FREE_BIN_DELTA, so we can just
+     shift.  */
+  bin = SIZE_BIN_DOWN (size);
+
+  if (bin <= NUM_FREE_BINS
+      && (chunk = zone->free_chunks[bin]) != NULL)
+    {
+      /* We have a chunk of the right size.  Pull it off the free list
+	 and use it.  */
+
+      zone->free_chunks[bin] = chunk->next_free;
+
+      /* NOTE: SIZE is only guaranteed to be right if MAX_ALIGNMENT
+	 == FREE_BIN_DELTA.  */
+      result = chunk;
+
+      /* The allocation bits are already set correctly.  HIGH_FREE_BIN
+	 may now be wrong, if this was the last chunk in the high bin.
+	 Rather than fixing it up now, wait until we need to search
+	 the free bins.  */
+
+      goto found;
+    }
+
+  /* Next, if there wasn't a chunk of the ideal size, look for a chunk
+     to split.  We can find one in the too-big bin, or in the largest
+     sized bin with a chunk in it.  Try the largest normal-sized bin
+     first.  */
+
+  if (zone->high_free_bin > bin)
+    {
+      /* Find the highest numbered free bin.  It will be at or below
+	 the watermark.  */
+      while (zone->high_free_bin > bin
+	     && zone->free_chunks[zone->high_free_bin] == NULL)
+	zone->high_free_bin--;
+
+      if (zone->high_free_bin > bin)
+	{
+	  size_t tbin = zone->high_free_bin;
+	  chunk = zone->free_chunks[tbin];
+
+	  /* Remove the chunk from its previous bin.  */
+	  zone->free_chunks[tbin] = chunk->next_free;
+
+	  result = (char *) chunk;
+
+	  /* Save the rest of the chunk for future allocation.  */
+	  if (zone->cached_free_size)
+	    free_chunk (zone->cached_free, zone->cached_free_size, zone);
+
+	  chunk = (struct alloc_chunk *) ((char *) result + size);
+	  zone->cached_free = (char *) chunk;
+	  zone->cached_free_size = (tbin - bin) * FREE_BIN_DELTA;
+
+	  /* Mark the new free chunk as an object, so that we can
+	     find the size of the newly allocated object.  */
+	  zone_set_object_alloc_bit (chunk);
+
+	  /* HIGH_FREE_BIN may now be wrong, if this was the last
+	     chunk in the high bin.  Rather than fixing it up now,
+	     wait until we need to search the free bins.  */
+
+	  goto found;
+	}
+    }
+
+  /* Failing that, look through the "other" bucket for a chunk
+     that is large enough.  */
+  pp = &(zone->free_chunks[0]);
+  chunk = *pp;
+  while (chunk && chunk->size < size)
+    {
+      pp = &chunk->next_free;
+      chunk = *pp;
+    }
+
+  if (chunk)
+    {
+      /* Remove the chunk from its previous bin.  */
+      *pp = chunk->next_free;
+
+      result = (char *) chunk;
+
+      /* Save the rest of the chunk for future allocation, if there's any
+	 left over.  */
+      csize = chunk->size;
+      if (csize > size)
+	{
+	  if (zone->cached_free_size)
+	    free_chunk (zone->cached_free, zone->cached_free_size, zone);
+
+	  chunk = (struct alloc_chunk *) ((char *) result + size);
+	  zone->cached_free = (char *) chunk;
+	  zone->cached_free_size = csize - size;
+
+	  /* Mark the new free chunk as an object.  */
+	  zone_set_object_alloc_bit (chunk);
+	}
+
+      goto found;
+    }
+
+  /* Handle large allocations.  We could choose any threshold between
+     GGC_PAGE_SIZE - sizeof (struct large_page_entry) and
+     GGC_PAGE_SIZE.  It can't be smaller, because then it wouldn't
+     be guaranteed to have a unique entry in the lookup table.  Large
+     allocations will always fall through to here.  */
+  if (size > GGC_PAGE_SIZE)
+    {
+      struct large_page_entry *entry = alloc_large_page (size, zone);
+
+#ifdef GATHER_STATISTICS
+      entry->common.survived = 0;
+#endif
+
+      entry->next = zone->large_pages;
+      if (zone->large_pages)
+	zone->large_pages->prev = entry;
+      zone->large_pages = entry;
+
+      result = entry->common.page;
+
+      goto found;
+    }
+
+  /* Failing everything above, allocate a new small page.  */
+
+  entry = alloc_small_page (zone);
+  entry->next = zone->pages;
+  zone->pages = entry;
+
+  /* Mark the first chunk in the new page.  */
+  entry->alloc_bits[0] = 1;
+
+  result = entry->common.page;
+  if (size < SMALL_PAGE_SIZE)
+    {
+      if (zone->cached_free_size)
+	free_chunk (zone->cached_free, zone->cached_free_size, zone);
+
+      zone->cached_free = (char *) result + size;
+      zone->cached_free_size = SMALL_PAGE_SIZE - size;
+
+      /* Mark the new free chunk as an object.  */
+      zone_set_object_alloc_bit (zone->cached_free);
+    }
+
+ found:
+
+  /* We could save TYPE in the chunk, but we don't use that for
+     anything yet.  If we wanted to, we could do it by adding it
+     either before the beginning of the chunk or after its end,
+     and adjusting the size and pointer appropriately.  */
+
+  /* We'll probably write to this after we return.  */
+  prefetchw (result);
+
+#ifdef ENABLE_GC_CHECKING
+  /* `Poison' the entire allocated object.  */
+  VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (result, size));
+  memset (result, 0xaf, size);
+  VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (result + orig_size,
+						size - orig_size));
+#endif
+
+  /* Tell Valgrind that the memory is there, but its content isn't
+     defined.  The bytes at the end of the object are still marked
+     unaccessible.  */
+  VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (result, orig_size));
+
+  /* Keep track of how many bytes are being allocated.  This
+     information is used in deciding when to collect.  */
+  zone->allocated += size;
+  
+  timevar_ggc_mem_total += size;
+
+#ifdef GATHER_STATISTICS
+  ggc_record_overhead (orig_size, size - orig_size, result PASS_MEM_STAT);
+
+  {
+    size_t object_size = size;
+    size_t overhead = object_size - orig_size;
+
+    zone->stats.total_overhead += overhead;
+    zone->stats.total_allocated += object_size;
+
+    if (orig_size <= 32)
+      {
+	zone->stats.total_overhead_under32 += overhead;
+	zone->stats.total_allocated_under32 += object_size;
+      }
+    if (orig_size <= 64)
+      {
+	zone->stats.total_overhead_under64 += overhead;
+	zone->stats.total_allocated_under64 += object_size;
+      }
+    if (orig_size <= 128)
+      {
+	zone->stats.total_overhead_under128 += overhead;
+	zone->stats.total_allocated_under128 += object_size;
+      }
+  }
+#endif
+
+  if (GGC_DEBUG_LEVEL >= 3)
+    fprintf (G.debug_file, "Allocating object, size=%lu at %p\n",
+	     (unsigned long) size, result);
+
+  return result;
+}
+
+/* Allocate a SIZE of chunk memory of GTE type, into an appropriate zone
+   for that type.  */
+
+void *
+ggc_alloc_typed_stat (enum gt_types_enum gte, size_t size
+		      MEM_STAT_DECL)
+{
+  switch (gte)
+    {
+    case gt_ggc_e_14lang_tree_node:
+      return ggc_alloc_zone_pass_stat (size, &tree_zone);
+
+    case gt_ggc_e_7rtx_def:
+      return ggc_alloc_zone_pass_stat (size, &rtl_zone);
+
+    case gt_ggc_e_9rtvec_def:
+      return ggc_alloc_zone_pass_stat (size, &rtl_zone);
+
+    default:
+      return ggc_alloc_zone_pass_stat (size, &main_zone);
+    }
+}
+
+/* Normal ggc_alloc simply allocates into the main zone.  */
+
+void *
+ggc_alloc_stat (size_t size MEM_STAT_DECL)
+{
+  return ggc_alloc_zone_pass_stat (size, &main_zone);
+}
+
+/* Poison the chunk.  */
+#ifdef ENABLE_GC_CHECKING
+#define poison_region(PTR, SIZE) \
+  memset ((PTR), 0xa5, (SIZE))
+#else
+#define poison_region(PTR, SIZE)
+#endif
+
+/* Free the object at P.  */
+
+void
+ggc_free (void *p)
+{
+  struct page_entry *page;
+
+#ifdef GATHER_STATISTICS
+  ggc_free_overhead (p);
+#endif
+
+  poison_region (p, ggc_get_size (p));
+
+  page = zone_get_object_page (p);
+
+  if (page->large_p)
+    {
+      struct large_page_entry *large_page
+	= (struct large_page_entry *) page;
+
+      /* Remove the page from the linked list.  */
+      if (large_page->prev)
+	large_page->prev->next = large_page->next;
+      else
+	{
+	  gcc_assert (large_page->common.zone->large_pages == large_page);
+	  large_page->common.zone->large_pages = large_page->next;
+	}
+      if (large_page->next)
+	large_page->next->prev = large_page->prev;
+
+      large_page->common.zone->allocated -= large_page->bytes;
+
+      /* Release the memory associated with this object.  */
+      free_large_page (large_page);
+    }
+  else if (page->pch_p)
+    /* Don't do anything.  We won't allocate a new object from the
+       PCH zone so there's no point in releasing anything.  */
+    ;
+  else
+    {
+      size_t size = ggc_get_size (p);
+
+      page->zone->allocated -= size;
+
+      /* Add the chunk to the free list.  We don't bother with coalescing,
+	 since we are likely to want a chunk of this size again.  */
+      free_chunk ((char *)p, size, page->zone);
+    }
+}
+
+/* Mark function for strings.  */
+
+void
+gt_ggc_m_S (const void *p)
+{
+  page_entry *entry;
+  unsigned long offset;
+
+  if (!p)
+    return;
+
+  /* Look up the page on which the object is alloced.  .  */
+  entry = lookup_page_table_if_allocated (p);
+  if (! entry)
+    return;
+
+  if (entry->pch_p)
+    {
+      size_t alloc_word, alloc_bit, t;
+      t = ((const char *) p - pch_zone.page) / BYTES_PER_ALLOC_BIT;
+      alloc_word = t / (8 * sizeof (alloc_type));
+      alloc_bit = t % (8 * sizeof (alloc_type));
+      offset = zone_find_object_offset (pch_zone.alloc_bits, alloc_word,
+					alloc_bit);
+    }
+  else if (entry->large_p)
+    {
+      struct large_page_entry *le = (struct large_page_entry *) entry;
+      offset = ((const char *) p) - entry->page;
+      gcc_assert (offset < le->bytes);
+    }
+  else
+    {
+      struct small_page_entry *se = (struct small_page_entry *) entry;
+      unsigned int start_word = zone_get_object_alloc_word (p);
+      unsigned int start_bit = zone_get_object_alloc_bit (p);
+      offset = zone_find_object_offset (se->alloc_bits, start_word, start_bit);
+
+      /* On some platforms a char* will not necessarily line up on an
+	 allocation boundary, so we have to update the offset to
+	 account for the leftover bytes.  */
+      offset += (size_t) p % BYTES_PER_ALLOC_BIT;
+    }
+
+  if (offset)
+    {
+      /* Here we've seen a char* which does not point to the beginning
+	 of an allocated object.  We assume it points to the middle of
+	 a STRING_CST.  */
+      gcc_assert (offset == offsetof (struct tree_string, str));
+      p = ((const char *) p) - offset;
+      gt_ggc_mx_lang_tree_node (CONST_CAST(void *, p));
+      return;
+    }
+
+  /* Inefficient, but also unlikely to matter.  */
+  ggc_set_mark (p);
+}
+
+/* If P is not marked, mark it and return false.  Otherwise return true.
+   P must have been allocated by the GC allocator; it mustn't point to
+   static objects, stack variables, or memory allocated with malloc.  */
+
+int
+ggc_set_mark (const void *p)
+{
+  struct page_entry *page;
+  const char *ptr = (const char *) p;
+
+  page = zone_get_object_page (p);
+
+  if (page->pch_p)
+    {
+      size_t mark_word, mark_bit, offset;
+      offset = (ptr - pch_zone.page) / BYTES_PER_MARK_BIT;
+      mark_word = offset / (8 * sizeof (mark_type));
+      mark_bit = offset % (8 * sizeof (mark_type));
+      
+      if (pch_zone.mark_bits[mark_word] & (1 << mark_bit))
+	return 1;
+      pch_zone.mark_bits[mark_word] |= (1 << mark_bit);
+    }
+  else if (page->large_p)
+    {
+      struct large_page_entry *large_page
+	= (struct large_page_entry *) page;
+
+      if (large_page->mark_p)
+	return 1;
+      large_page->mark_p = true;
+    }
+  else
+    {
+      struct small_page_entry *small_page
+	= (struct small_page_entry *) page;
+
+      if (small_page->mark_bits[zone_get_object_mark_word (p)]
+	  & (1 << zone_get_object_mark_bit (p)))
+	return 1;
+      small_page->mark_bits[zone_get_object_mark_word (p)]
+	|= (1 << zone_get_object_mark_bit (p));
+    }
+
+  if (GGC_DEBUG_LEVEL >= 4)
+    fprintf (G.debug_file, "Marking %p\n", p);
+
+  return 0;
+}
+
+/* Return 1 if P has been marked, zero otherwise.
+   P must have been allocated by the GC allocator; it mustn't point to
+   static objects, stack variables, or memory allocated with malloc.  */
+
+int
+ggc_marked_p (const void *p)
+{
+  struct page_entry *page;
+  const char *ptr = (const char *) p;
+
+  page = zone_get_object_page (p);
+
+  if (page->pch_p)
+    {
+      size_t mark_word, mark_bit, offset;
+      offset = (ptr - pch_zone.page) / BYTES_PER_MARK_BIT;
+      mark_word = offset / (8 * sizeof (mark_type));
+      mark_bit = offset % (8 * sizeof (mark_type));
+      
+      return (pch_zone.mark_bits[mark_word] & (1 << mark_bit)) != 0;
+    }
+
+  if (page->large_p)
+    {
+      struct large_page_entry *large_page
+	= (struct large_page_entry *) page;
+
+      return large_page->mark_p;
+    }
+  else
+    {
+      struct small_page_entry *small_page
+	= (struct small_page_entry *) page;
+
+      return 0 != (small_page->mark_bits[zone_get_object_mark_word (p)]
+		   & (1 << zone_get_object_mark_bit (p)));
+    }
+}
+
+/* Return the size of the gc-able object P.  */
+
+size_t
+ggc_get_size (const void *p)
+{
+  struct page_entry *page;
+  const char *ptr = (const char *) p;
+
+  page = zone_get_object_page (p);
+
+  if (page->pch_p)
+    {
+      size_t alloc_word, alloc_bit, offset, max_size;
+      offset = (ptr - pch_zone.page) / BYTES_PER_ALLOC_BIT + 1;
+      alloc_word = offset / (8 * sizeof (alloc_type));
+      alloc_bit = offset % (8 * sizeof (alloc_type));
+      max_size = pch_zone.bytes - (ptr - pch_zone.page);
+      return zone_object_size_1 (pch_zone.alloc_bits, alloc_word, alloc_bit,
+				 max_size);
+    }
+
+  if (page->large_p)
+    return ((struct large_page_entry *)page)->bytes;
+  else
+    return zone_find_object_size ((struct small_page_entry *) page, p);
+}
+
+/* Initialize the ggc-zone-mmap allocator.  */
+void
+init_ggc (void)
+{
+  /* The allocation size must be greater than BYTES_PER_MARK_BIT, and
+     a multiple of both BYTES_PER_ALLOC_BIT and FREE_BIN_DELTA, for
+     the current assumptions to hold.  */
+
+  gcc_assert (FREE_BIN_DELTA == MAX_ALIGNMENT);
+
+  /* Set up the main zone by hand.  */
+  main_zone.name = "Main zone";
+  G.zones = &main_zone;
+
+  /* Allocate the default zones.  */
+  new_ggc_zone_1 (&rtl_zone, "RTL zone");
+  new_ggc_zone_1 (&tree_zone, "Tree zone");
+  new_ggc_zone_1 (&tree_id_zone, "Tree identifier zone");
+
+  G.pagesize = getpagesize();
+  G.lg_pagesize = exact_log2 (G.pagesize);
+  G.page_mask = ~(G.pagesize - 1);
+
+  /* Require the system page size to be a multiple of GGC_PAGE_SIZE.  */
+  gcc_assert ((G.pagesize & (GGC_PAGE_SIZE - 1)) == 0);
+
+  /* Allocate 16 system pages at a time.  */
+  G.quire_size = 16 * G.pagesize / GGC_PAGE_SIZE;
+
+  /* Calculate the size of the allocation bitmap and other overhead.  */
+  /* Right now we allocate bits for the page header and bitmap.  These
+     are wasted, but a little tricky to eliminate.  */
+  G.small_page_overhead
+    = PAGE_OVERHEAD + (GGC_PAGE_SIZE / BYTES_PER_ALLOC_BIT / 8);
+  /* G.small_page_overhead = ROUND_UP (G.small_page_overhead, MAX_ALIGNMENT); */
+
+#ifdef HAVE_MMAP_DEV_ZERO
+  G.dev_zero_fd = open ("/dev/zero", O_RDONLY);
+  gcc_assert (G.dev_zero_fd != -1);
+#endif
+
+#if 0
+  G.debug_file = fopen ("ggc-mmap.debug", "w");
+  setlinebuf (G.debug_file);
+#else
+  G.debug_file = stdout;
+#endif
+
+#ifdef USING_MMAP
+  /* StunOS has an amazing off-by-one error for the first mmap allocation
+     after fiddling with RLIMIT_STACK.  The result, as hard as it is to
+     believe, is an unaligned page allocation, which would cause us to
+     hork badly if we tried to use it.  */
+  {
+    char *p = alloc_anon (NULL, G.pagesize, &main_zone);
+    struct small_page_entry *e;
+    if ((size_t)p & (G.pagesize - 1))
+      {
+	/* How losing.  Discard this one and try another.  If we still
+	   can't get something useful, give up.  */
+
+	p = alloc_anon (NULL, G.pagesize, &main_zone);
+	gcc_assert (!((size_t)p & (G.pagesize - 1)));
+      }
+
+    if (GGC_PAGE_SIZE == G.pagesize)
+      {
+	/* We have a good page, might as well hold onto it...  */
+	e = XCNEWVAR (struct small_page_entry, G.small_page_overhead);
+	e->common.page = p;
+	e->common.zone = &main_zone;
+	e->next = main_zone.free_pages;
+	set_page_table_entry (e->common.page, &e->common);
+	main_zone.free_pages = e;
+      }
+    else
+      {
+	munmap (p, G.pagesize);
+      }
+  }
+#endif
+}
+
+/* Start a new GGC zone.  */
+
+static void
+new_ggc_zone_1 (struct alloc_zone *new_zone, const char * name)
+{
+  new_zone->name = name;
+  new_zone->next_zone = G.zones->next_zone;
+  G.zones->next_zone = new_zone;
+}
+
+struct alloc_zone *
+new_ggc_zone (const char * name)
+{
+  struct alloc_zone *new_zone = XCNEW (struct alloc_zone);
+  new_ggc_zone_1 (new_zone, name);
+  return new_zone;
+}
+
+/* Destroy a GGC zone.  */
+void
+destroy_ggc_zone (struct alloc_zone * dead_zone)
+{
+  struct alloc_zone *z;
+
+  for (z = G.zones; z && z->next_zone != dead_zone; z = z->next_zone)
+    /* Just find that zone.  */
+    continue;
+
+  /* We should have found the zone in the list.  Anything else is fatal.  */
+  gcc_assert (z);
+
+  /* z is dead, baby. z is dead.  */
+  z->dead = true;
+}
+
+/* Free all empty pages and objects within a page for a given zone  */
+
+static void
+sweep_pages (struct alloc_zone *zone)
+{
+  struct large_page_entry **lpp, *lp, *lnext;
+  struct small_page_entry **spp, *sp, *snext;
+  char *last_free;
+  size_t allocated = 0;
+  bool nomarksinpage;
+
+  /* First, reset the free_chunks lists, since we are going to
+     re-free free chunks in hopes of coalescing them into large chunks.  */
+  memset (zone->free_chunks, 0, sizeof (zone->free_chunks));
+  zone->high_free_bin = 0;
+  zone->cached_free = NULL;
+  zone->cached_free_size = 0;
+
+  /* Large pages are all or none affairs. Either they are completely
+     empty, or they are completely full.  */
+  lpp = &zone->large_pages;
+  for (lp = zone->large_pages; lp != NULL; lp = lnext)
+    {
+      gcc_assert (lp->common.large_p);
+
+      lnext = lp->next;
+
+#ifdef GATHER_STATISTICS
+      /* This page has now survived another collection.  */
+      lp->common.survived++;
+#endif
+
+      if (lp->mark_p)
+	{
+	  lp->mark_p = false;
+	  allocated += lp->bytes;
+	  lpp = &lp->next;
+	}
+      else
+	{
+	  *lpp = lnext;
+#ifdef ENABLE_GC_CHECKING
+	  /* Poison the page.  */
+	  memset (lp->common.page, 0xb5, SMALL_PAGE_SIZE);
+#endif
+	  if (lp->prev)
+	    lp->prev->next = lp->next;
+	  if (lp->next)
+	    lp->next->prev = lp->prev;
+	  free_large_page (lp);
+	}
+    }
+
+  spp = &zone->pages;
+  for (sp = zone->pages; sp != NULL; sp = snext)
+    {
+      char *object, *last_object;
+      char *end;
+      alloc_type *alloc_word_p;
+      mark_type *mark_word_p;
+
+      gcc_assert (!sp->common.large_p);
+
+      snext = sp->next;
+
+#ifdef GATHER_STATISTICS
+      /* This page has now survived another collection.  */
+      sp->common.survived++;
+#endif
+
+      /* Step through all chunks, consolidate those that are free and
+	 insert them into the free lists.  Note that consolidation
+	 slows down collection slightly.  */
+
+      last_object = object = sp->common.page;
+      end = sp->common.page + SMALL_PAGE_SIZE;
+      last_free = NULL;
+      nomarksinpage = true;
+      mark_word_p = sp->mark_bits;
+      alloc_word_p = sp->alloc_bits;
+
+      gcc_assert (BYTES_PER_ALLOC_BIT == BYTES_PER_MARK_BIT);
+
+      object = sp->common.page;
+      do
+	{
+	  unsigned int i, n;
+	  alloc_type alloc_word;
+	  mark_type mark_word;
+
+	  alloc_word = *alloc_word_p++;
+	  mark_word = *mark_word_p++;
+
+	  if (mark_word)
+	    nomarksinpage = false;
+
+	  /* There ought to be some way to do this without looping...  */
+	  i = 0;
+	  while ((n = alloc_ffs (alloc_word)) != 0)
+	    {
+	      /* Extend the current state for n - 1 bits.  We can't
+		 shift alloc_word by n, even though it isn't used in the
+		 loop, in case only the highest bit was set.  */
+	      alloc_word >>= n - 1;
+	      mark_word >>= n - 1;
+	      object += BYTES_PER_MARK_BIT * (n - 1);
+
+	      if (mark_word & 1)
+		{
+		  if (last_free)
+		    {
+		      VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (last_free,
+								     object
+								     - last_free));
+		      poison_region (last_free, object - last_free);
+		      free_chunk (last_free, object - last_free, zone);
+		      last_free = NULL;
+		    }
+		  else
+		    allocated += object - last_object;
+		  last_object = object;
+		}
+	      else
+		{
+		  if (last_free == NULL)
+		    {
+		      last_free = object;
+		      allocated += object - last_object;
+		    }
+		  else
+		    zone_clear_object_alloc_bit (sp, object);
+		}
+
+	      /* Shift to just after the alloc bit we handled.  */
+	      alloc_word >>= 1;
+	      mark_word >>= 1;
+	      object += BYTES_PER_MARK_BIT;
+
+	      i += n;
+	    }
+
+	  object += BYTES_PER_MARK_BIT * (8 * sizeof (alloc_type) - i);
+	}
+      while (object < end);
+
+      if (nomarksinpage)
+	{
+	  *spp = snext;
+#ifdef ENABLE_GC_CHECKING
+	  VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (sp->common.page,
+							 SMALL_PAGE_SIZE));
+	  /* Poison the page.  */
+	  memset (sp->common.page, 0xb5, SMALL_PAGE_SIZE);
+#endif
+	  free_small_page (sp);
+	  continue;
+	}
+      else if (last_free)
+	{
+	  VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (last_free,
+							 object - last_free));
+	  poison_region (last_free, object - last_free);
+	  free_chunk (last_free, object - last_free, zone);
+	}
+      else
+	allocated += object - last_object;
+
+      spp = &sp->next;
+    }
+
+  zone->allocated = allocated;
+}
+
+/* mark-and-sweep routine for collecting a single zone.  NEED_MARKING
+   is true if we need to mark before sweeping, false if some other
+   zone collection has already performed marking for us.  Returns true
+   if we collected, false otherwise.  */
+
+static bool
+ggc_collect_1 (struct alloc_zone *zone, bool need_marking)
+{
+#if 0
+  /* */
+  {
+    int i;
+    for (i = 0; i < NUM_FREE_BINS + 1; i++)
+      {
+	struct alloc_chunk *chunk;
+	int n, tot;
+
+	n = 0;
+	tot = 0;
+	chunk = zone->free_chunks[i];
+	while (chunk)
+	  {
+	    n++;
+	    tot += chunk->size;
+	    chunk = chunk->next_free;
+	  }
+	fprintf (stderr, "Bin %d: %d free chunks (%d bytes)\n",
+		 i, n, tot);
+      }
+  }
+  /* */
+#endif
+
+  if (!quiet_flag)
+    fprintf (stderr, " {%s GC %luk -> ",
+	     zone->name, (unsigned long) zone->allocated / 1024);
+
+  /* Zero the total allocated bytes.  This will be recalculated in the
+     sweep phase.  */
+  zone->allocated = 0;
+
+  /* Release the pages we freed the last time we collected, but didn't
+     reuse in the interim.  */
+  release_pages (zone);
+
+  if (need_marking)
+    {
+      zone_allocate_marks ();
+      ggc_mark_roots ();
+#ifdef GATHER_STATISTICS
+      ggc_prune_overhead_list ();
+#endif
+    }
+  
+  sweep_pages (zone);
+  zone->was_collected = true;
+  zone->allocated_last_gc = zone->allocated;
+
+  if (!quiet_flag)
+    fprintf (stderr, "%luk}", (unsigned long) zone->allocated / 1024);
+  return true;
+}
+
+#ifdef GATHER_STATISTICS
+/* Calculate the average page survival rate in terms of number of
+   collections.  */
+
+static float
+calculate_average_page_survival (struct alloc_zone *zone)
+{
+  float count = 0.0;
+  float survival = 0.0;
+  struct small_page_entry *p;
+  struct large_page_entry *lp;
+  for (p = zone->pages; p; p = p->next)
+    {
+      count += 1.0;
+      survival += p->common.survived;
+    }
+  for (lp = zone->large_pages; lp; lp = lp->next)
+    {
+      count += 1.0;
+      survival += lp->common.survived;
+    }
+  return survival/count;
+}
+#endif
+
+/* Top level collection routine.  */
+
+void
+ggc_collect (void)
+{
+  struct alloc_zone *zone;
+  bool marked = false;
+
+  timevar_push (TV_GC);
+
+  if (!ggc_force_collect)
+    {
+      float allocated_last_gc = 0, allocated = 0, min_expand;
+
+      for (zone = G.zones; zone; zone = zone->next_zone)
+	{
+	  allocated_last_gc += zone->allocated_last_gc;
+	  allocated += zone->allocated;
+	}
+
+      allocated_last_gc =
+	MAX (allocated_last_gc,
+	     (size_t) PARAM_VALUE (GGC_MIN_HEAPSIZE) * 1024);
+      min_expand = allocated_last_gc * PARAM_VALUE (GGC_MIN_EXPAND) / 100;
+
+      if (allocated < allocated_last_gc + min_expand)
+	{
+	  timevar_pop (TV_GC);
+	  return;
+	}
+    }
+
+  /* Start by possibly collecting the main zone.  */
+  main_zone.was_collected = false;
+  marked |= ggc_collect_1 (&main_zone, true);
+
+  /* In order to keep the number of collections down, we don't
+     collect other zones unless we are collecting the main zone.  This
+     gives us roughly the same number of collections as we used to
+     have with the old gc.  The number of collection is important
+     because our main slowdown (according to profiling) is now in
+     marking.  So if we mark twice as often as we used to, we'll be
+     twice as slow.  Hopefully we'll avoid this cost when we mark
+     zone-at-a-time.  */
+  /* NOTE drow/2004-07-28: We now always collect the main zone, but
+     keep this code in case the heuristics are further refined.  */
+
+  if (main_zone.was_collected)
+    {
+      struct alloc_zone *zone;
+
+      for (zone = main_zone.next_zone; zone; zone = zone->next_zone)
+	{
+	  zone->was_collected = false;
+	  marked |= ggc_collect_1 (zone, !marked);
+	}
+    }
+
+#ifdef GATHER_STATISTICS
+  /* Print page survival stats, if someone wants them.  */
+  if (GGC_DEBUG_LEVEL >= 2)
+    {
+      for (zone = G.zones; zone; zone = zone->next_zone)
+	{
+	  if (zone->was_collected)
+	    {
+	      float f = calculate_average_page_survival (zone);
+	      printf ("Average page survival in zone `%s' is %f\n",
+		      zone->name, f);
+	    }
+	}
+    }
+#endif
+
+  if (marked)
+    zone_free_marks ();
+
+  /* Free dead zones.  */
+  for (zone = G.zones; zone && zone->next_zone; zone = zone->next_zone)
+    {
+      if (zone->next_zone->dead)
+	{
+	  struct alloc_zone *dead_zone = zone->next_zone;
+
+	  printf ("Zone `%s' is dead and will be freed.\n", dead_zone->name);
+
+	  /* The zone must be empty.  */
+	  gcc_assert (!dead_zone->allocated);
+
+	  /* Unchain the dead zone, release all its pages and free it.  */
+	  zone->next_zone = zone->next_zone->next_zone;
+	  release_pages (dead_zone);
+	  free (dead_zone);
+	}
+    }
+
+  timevar_pop (TV_GC);
+}
+
+/* Print allocation statistics.  */
+#define SCALE(x) ((unsigned long) ((x) < 1024*10 \
+		  ? (x) \
+		  : ((x) < 1024*1024*10 \
+		     ? (x) / 1024 \
+		     : (x) / (1024*1024))))
+#define LABEL(x) ((x) < 1024*10 ? ' ' : ((x) < 1024*1024*10 ? 'k' : 'M'))
+
+void
+ggc_print_statistics (void)
+{
+  struct alloc_zone *zone;
+  struct ggc_statistics stats;
+  size_t total_overhead = 0, total_allocated = 0, total_bytes_mapped = 0;
+  size_t pte_overhead, i;
+
+  /* Clear the statistics.  */
+  memset (&stats, 0, sizeof (stats));
+
+  /* Make sure collection will really occur.  */
+  ggc_force_collect = true;
+
+  /* Collect and print the statistics common across collectors.  */
+  ggc_print_common_statistics (stderr, &stats);
+
+  ggc_force_collect = false;
+
+  /* Release free pages so that we will not count the bytes allocated
+     there as part of the total allocated memory.  */
+  for (zone = G.zones; zone; zone = zone->next_zone)
+    release_pages (zone);
+
+  /* Collect some information about the various sizes of
+     allocation.  */
+  fprintf (stderr,
+           "Memory still allocated at the end of the compilation process\n");
+
+  fprintf (stderr, "%20s %10s  %10s  %10s\n",
+	   "Zone", "Allocated", "Used", "Overhead");
+  for (zone = G.zones; zone; zone = zone->next_zone)
+    {
+      struct large_page_entry *large_page;
+      size_t overhead, allocated, in_use;
+
+      /* Skip empty zones.  */
+      if (!zone->pages && !zone->large_pages)
+	continue;
+
+      allocated = in_use = 0;
+
+      overhead = sizeof (struct alloc_zone);
+
+      for (large_page = zone->large_pages; large_page != NULL;
+	   large_page = large_page->next)
+	{
+	  allocated += large_page->bytes;
+	  in_use += large_page->bytes;
+	  overhead += sizeof (struct large_page_entry);
+	}
+
+      /* There's no easy way to walk through the small pages finding
+	 used and unused objects.  Instead, add all the pages, and
+	 subtract out the free list.  */
+
+      allocated += GGC_PAGE_SIZE * zone->n_small_pages;
+      in_use += GGC_PAGE_SIZE * zone->n_small_pages;
+      overhead += G.small_page_overhead * zone->n_small_pages;
+
+      for (i = 0; i <= NUM_FREE_BINS; i++)
+	{
+	  struct alloc_chunk *chunk = zone->free_chunks[i];
+	  while (chunk)
+	    {
+	      in_use -= ggc_get_size (chunk);
+	      chunk = chunk->next_free;
+	    }
+	}
+      
+      fprintf (stderr, "%20s %10lu%c %10lu%c %10lu%c\n",
+	       zone->name,
+	       SCALE (allocated), LABEL (allocated),
+	       SCALE (in_use), LABEL (in_use),
+	       SCALE (overhead), LABEL (overhead));
+
+      gcc_assert (in_use == zone->allocated);
+
+      total_overhead += overhead;
+      total_allocated += zone->allocated;
+      total_bytes_mapped += zone->bytes_mapped;
+    }
+
+  /* Count the size of the page table as best we can.  */
+#if HOST_BITS_PER_PTR <= 32
+  pte_overhead = sizeof (G.lookup);
+  for (i = 0; i < PAGE_L1_SIZE; i++)
+    if (G.lookup[i])
+      pte_overhead += PAGE_L2_SIZE * sizeof (struct page_entry *);
+#else
+  {
+    page_table table = G.lookup;
+    pte_overhead = 0;
+    while (table)
+      {
+	pte_overhead += sizeof (*table);
+	for (i = 0; i < PAGE_L1_SIZE; i++)
+	  if (table->table[i])
+	    pte_overhead += PAGE_L2_SIZE * sizeof (struct page_entry *);
+	table = table->next;
+      }
+  }
+#endif
+  fprintf (stderr, "%20s %11s %11s %10lu%c\n", "Page Table",
+	   "", "", SCALE (pte_overhead), LABEL (pte_overhead));
+  total_overhead += pte_overhead;
+
+  fprintf (stderr, "%20s %10lu%c %10lu%c %10lu%c\n", "Total",
+	   SCALE (total_bytes_mapped), LABEL (total_bytes_mapped),
+	   SCALE (total_allocated), LABEL(total_allocated),
+	   SCALE (total_overhead), LABEL (total_overhead));
+
+#ifdef GATHER_STATISTICS  
+  {
+    unsigned long long all_overhead = 0, all_allocated = 0;
+    unsigned long long all_overhead_under32 = 0, all_allocated_under32 = 0;
+    unsigned long long all_overhead_under64 = 0, all_allocated_under64 = 0;
+    unsigned long long all_overhead_under128 = 0, all_allocated_under128 = 0;
+
+    fprintf (stderr, "\nTotal allocations and overheads during the compilation process\n");
+
+    for (zone = G.zones; zone; zone = zone->next_zone)
+      {
+	all_overhead += zone->stats.total_overhead;
+	all_allocated += zone->stats.total_allocated;
+
+	all_allocated_under32 += zone->stats.total_allocated_under32;
+	all_overhead_under32 += zone->stats.total_overhead_under32;
+
+	all_allocated_under64 += zone->stats.total_allocated_under64;
+	all_overhead_under64 += zone->stats.total_overhead_under64;
+	
+	all_allocated_under128 += zone->stats.total_allocated_under128;
+	all_overhead_under128 += zone->stats.total_overhead_under128;
+
+	fprintf (stderr, "%20s:                  %10lld\n",
+		 zone->name, zone->stats.total_allocated);
+      }
+
+    fprintf (stderr, "\n");
+
+    fprintf (stderr, "Total Overhead:                        %10lld\n",
+             all_overhead);
+    fprintf (stderr, "Total Allocated:                       %10lld\n",
+             all_allocated);
+
+    fprintf (stderr, "Total Overhead  under  32B:            %10lld\n",
+             all_overhead_under32);
+    fprintf (stderr, "Total Allocated under  32B:            %10lld\n",
+             all_allocated_under32);
+    fprintf (stderr, "Total Overhead  under  64B:            %10lld\n",
+             all_overhead_under64);
+    fprintf (stderr, "Total Allocated under  64B:            %10lld\n",
+             all_allocated_under64);
+    fprintf (stderr, "Total Overhead  under 128B:            %10lld\n",
+             all_overhead_under128);
+    fprintf (stderr, "Total Allocated under 128B:            %10lld\n",
+             all_allocated_under128);
+  }
+#endif
+}
+
+/* Precompiled header support.  */
+
+/* For precompiled headers, we sort objects based on their type.  We
+   also sort various objects into their own buckets; currently this
+   covers strings and IDENTIFIER_NODE trees.  The choices of how
+   to sort buckets have not yet been tuned.  */
+
+#define NUM_PCH_BUCKETS		(gt_types_enum_last + 3)
+
+#define OTHER_BUCKET		(gt_types_enum_last + 0)
+#define IDENTIFIER_BUCKET	(gt_types_enum_last + 1)
+#define STRING_BUCKET		(gt_types_enum_last + 2)
+
+struct ggc_pch_ondisk
+{
+  size_t total;
+  size_t type_totals[NUM_PCH_BUCKETS];
+};
+
+struct ggc_pch_data
+{
+  struct ggc_pch_ondisk d;
+  size_t base;
+  size_t orig_base;
+  size_t alloc_size;
+  alloc_type *alloc_bits;
+  size_t type_bases[NUM_PCH_BUCKETS];
+  size_t start_offset;
+};
+
+/* Initialize the PCH data structure.  */
+
+struct ggc_pch_data *
+init_ggc_pch (void)
+{
+  return XCNEW (struct ggc_pch_data);
+}
+
+/* Return which of the page-aligned buckets the object at X, with type
+   TYPE, should be sorted into in the PCH.  Strings will have
+   IS_STRING set and TYPE will be gt_types_enum_last.  Other objects
+   of unknown type will also have TYPE equal to gt_types_enum_last.  */
+
+static int
+pch_bucket (void *x, enum gt_types_enum type,
+	    bool is_string)
+{
+  /* Sort identifiers into their own bucket, to improve locality
+     when searching the identifier hash table.  */
+  if (type == gt_ggc_e_14lang_tree_node
+      && TREE_CODE ((tree) x) == IDENTIFIER_NODE)
+    return IDENTIFIER_BUCKET;
+  else if (type == gt_types_enum_last)
+    {
+      if (is_string)
+	return STRING_BUCKET;
+      return OTHER_BUCKET;
+    }
+  return type;
+}
+
+/* Add the size of object X to the size of the PCH data.  */
+
+void
+ggc_pch_count_object (struct ggc_pch_data *d, void *x ATTRIBUTE_UNUSED,
+		      size_t size, bool is_string, enum gt_types_enum type)
+{
+  /* NOTE: Right now we don't need to align up the size of any objects.
+     Strings can be unaligned, and everything else is allocated to a
+     MAX_ALIGNMENT boundary already.  */
+
+  d->d.type_totals[pch_bucket (x, type, is_string)] += size;
+}
+
+/* Return the total size of the PCH data.  */
+
+size_t
+ggc_pch_total_size (struct ggc_pch_data *d)
+{
+  enum gt_types_enum i;
+  size_t alloc_size, total_size;
+
+  total_size = 0;
+  for (i = 0; i < NUM_PCH_BUCKETS; i++)
+    {
+      d->d.type_totals[i] = ROUND_UP (d->d.type_totals[i], GGC_PAGE_SIZE);
+      total_size += d->d.type_totals[i];
+    }
+  d->d.total = total_size;
+
+  /* Include the size of the allocation bitmap.  */
+  alloc_size = CEIL (d->d.total, BYTES_PER_ALLOC_BIT * 8);
+  alloc_size = ROUND_UP (alloc_size, MAX_ALIGNMENT);
+  d->alloc_size = alloc_size;
+
+  return d->d.total + alloc_size;
+}
+
+/* Set the base address for the objects in the PCH file.  */
+
+void
+ggc_pch_this_base (struct ggc_pch_data *d, void *base_)
+{
+  int i;
+  size_t base = (size_t) base_;
+
+  d->base = d->orig_base = base;
+  for (i = 0; i < NUM_PCH_BUCKETS; i++)
+    {
+      d->type_bases[i] = base;
+      base += d->d.type_totals[i];
+    }
+
+  if (d->alloc_bits == NULL)
+    d->alloc_bits = XCNEWVAR (alloc_type, d->alloc_size);
+}
+
+/* Allocate a place for object X of size SIZE in the PCH file.  */
+
+char *
+ggc_pch_alloc_object (struct ggc_pch_data *d, void *x,
+		      size_t size, bool is_string,
+		      enum gt_types_enum type)
+{
+  size_t alloc_word, alloc_bit;
+  char *result;
+  int bucket = pch_bucket (x, type, is_string);
+
+  /* Record the start of the object in the allocation bitmap.  We
+     can't assert that the allocation bit is previously clear, because
+     strings may violate the invariant that they are at least
+     BYTES_PER_ALLOC_BIT long.  This is harmless - ggc_get_size
+     should not be called for strings.  */
+  alloc_word = ((d->type_bases[bucket] - d->orig_base)
+		/ (8 * sizeof (alloc_type) * BYTES_PER_ALLOC_BIT));
+  alloc_bit = ((d->type_bases[bucket] - d->orig_base)
+	       / BYTES_PER_ALLOC_BIT) % (8 * sizeof (alloc_type));
+  d->alloc_bits[alloc_word] |= 1L << alloc_bit;
+
+  /* Place the object at the current pointer for this bucket.  */
+  result = (char *) d->type_bases[bucket];
+  d->type_bases[bucket] += size;
+  return result;
+}
+
+/* Prepare to write out the PCH data to file F.  */
+
+void
+ggc_pch_prepare_write (struct ggc_pch_data *d,
+		       FILE *f)
+{
+  /* We seek around a lot while writing.  Record where the end
+     of the padding in the PCH file is, so that we can
+     locate each object's offset.  */
+  d->start_offset = ftell (f);
+}
+
+/* Write out object X of SIZE to file F.  */
+
+void
+ggc_pch_write_object (struct ggc_pch_data *d,
+		      FILE *f, void *x, void *newx,
+		      size_t size, bool is_string ATTRIBUTE_UNUSED)
+{
+  if (fseek (f, (size_t) newx - d->orig_base + d->start_offset, SEEK_SET) != 0)
+    fatal_error ("can't seek PCH file: %m");
+
+  if (fwrite (x, size, 1, f) != 1)
+    fatal_error ("can't write PCH file: %m");
+}
+
+void
+ggc_pch_finish (struct ggc_pch_data *d, FILE *f)
+{
+  /* Write out the allocation bitmap.  */
+  if (fseek (f, d->start_offset + d->d.total, SEEK_SET) != 0)
+    fatal_error ("can't seek PCH file: %m");
+
+  if (fwrite (d->alloc_bits, d->alloc_size, 1, f) != 1)
+    fatal_error ("can't write PCH file: %m");
+
+  /* Done with the PCH, so write out our footer.  */
+  if (fwrite (&d->d, sizeof (d->d), 1, f) != 1)
+    fatal_error ("can't write PCH file: %m");
+
+  free (d->alloc_bits);
+  free (d);
+}
+
+/* The PCH file from F has been mapped at ADDR.  Read in any
+   additional data from the file and set up the GC state.  */
+
+void
+ggc_pch_read (FILE *f, void *addr)
+{
+  struct ggc_pch_ondisk d;
+  size_t alloc_size;
+  struct alloc_zone *zone;
+  struct page_entry *pch_page;
+  char *p;
+
+  if (fread (&d, sizeof (d), 1, f) != 1)
+    fatal_error ("can't read PCH file: %m");
+
+  alloc_size = CEIL (d.total, BYTES_PER_ALLOC_BIT * 8);
+  alloc_size = ROUND_UP (alloc_size, MAX_ALIGNMENT);
+
+  pch_zone.bytes = d.total;
+  pch_zone.alloc_bits = (alloc_type *) ((char *) addr + pch_zone.bytes);
+  pch_zone.page = (char *) addr;
+  pch_zone.end = (char *) pch_zone.alloc_bits;
+
+  /* We've just read in a PCH file.  So, every object that used to be
+     allocated is now free.  */
+  for (zone = G.zones; zone; zone = zone->next_zone)
+    {
+      struct small_page_entry *page, *next_page;
+      struct large_page_entry *large_page, *next_large_page;
+
+      zone->allocated = 0;
+
+      /* Clear the zone's free chunk list.  */
+      memset (zone->free_chunks, 0, sizeof (zone->free_chunks));
+      zone->high_free_bin = 0;
+      zone->cached_free = NULL;
+      zone->cached_free_size = 0;
+
+      /* Move all the small pages onto the free list.  */
+      for (page = zone->pages; page != NULL; page = next_page)
+	{
+	  next_page = page->next;
+	  memset (page->alloc_bits, 0,
+		  G.small_page_overhead - PAGE_OVERHEAD);
+	  free_small_page (page);
+	}
+
+      /* Discard all the large pages.  */
+      for (large_page = zone->large_pages; large_page != NULL;
+	   large_page = next_large_page)
+	{
+	  next_large_page = large_page->next;
+	  free_large_page (large_page);
+	}
+
+      zone->pages = NULL;
+      zone->large_pages = NULL;
+    }
+
+  /* Allocate the dummy page entry for the PCH, and set all pages
+     mapped into the PCH to reference it.  */
+  pch_page = XCNEW (struct page_entry);
+  pch_page->page = pch_zone.page;
+  pch_page->pch_p = true;
+
+  for (p = pch_zone.page; p < pch_zone.end; p += GGC_PAGE_SIZE)
+    set_page_table_entry (p, pch_page);
+}