1 files changed, 52 insertions, 1 deletions

diff --git a/gcc/ggc-page.c b/gcc/ggc-page.c
index ea637b1b63c..f22ddf6e826 100644
--- a/gcc/ggc-page.c
+++ b/gcc/ggc-page.c
@@ -1,5 +1,5 @@
 /* "Bag-of-pages" garbage collector for the GNU compiler.
-   Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007
+   Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -1256,6 +1256,57 @@ ggc_alloc_stat (size_t size MEM_STAT_DECL)
   return result;
 }
 
+/* Mark function for strings.  */
+
+void
+gt_ggc_m_S (const void *p)
+{
+  page_entry *entry;
+  unsigned bit, word;
+  unsigned long mask;
+  unsigned long offset;
+
+  if (!p || !ggc_allocated_p (p))
+    return;
+
+  /* Look up the page on which the object is alloced.  .  */
+  entry = lookup_page_table_entry (p);
+  gcc_assert (entry);
+
+  /* Calculate the index of the object on the page; this is its bit
+     position in the in_use_p bitmap.  Note that because a char* might
+     point to the middle of an object, we need special code here to
+     make sure P points to the start of an object.  */
+  offset = ((const char *) p - entry->page) % object_size_table[entry->order];
+  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 ((void *) p);
+      return;
+    }
+
+  bit = OFFSET_TO_BIT (((const char *) p) - entry->page, entry->order);
+  word = bit / HOST_BITS_PER_LONG;
+  mask = (unsigned long) 1 << (bit % HOST_BITS_PER_LONG);
+
+  /* If the bit was previously set, skip it.  */
+  if (entry->in_use_p[word] & mask)
+    return;
+
+  /* Otherwise set it, and decrement the free object count.  */
+  entry->in_use_p[word] |= mask;
+  entry->num_free_objects -= 1;
+
+  if (GGC_DEBUG_LEVEL >= 4)
+    fprintf (G.debug_file, "Marking %p\n", p);
+
+  return;
+}
+
 /* If P is not marked, marks 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.  */