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diff --git a/gc/gc_alloc.h b/gc/gc_alloc.h
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+/*
+ * Copyright (c) 1996-1998 by Silicon Graphics.  All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+
+//
+// This is a C++ header file that is intended to replace the SGI STL
+// alloc.h.  This assumes SGI STL version < 3.0.
+//
+// This assumes the collector has been compiled with -DATOMIC_UNCOLLECTABLE
+// and -DALL_INTERIOR_POINTERS.  We also recommend
+// -DREDIRECT_MALLOC=GC_uncollectable_malloc.
+//
+// Some of this could be faster in the explicit deallocation case.  In particular,
+// we spend too much time clearing objects on the free lists.  That could be avoided.
+//
+// This uses template classes with static members, and hence does not work
+// with g++ 2.7.2 and earlier.
+//
+
+#include "gc.h"
+
+#ifndef GC_ALLOC_H
+
+#define GC_ALLOC_H
+#define __ALLOC_H	// Prevent inclusion of the default version.  Ugly.
+#define __SGI_STL_ALLOC_H
+#define __SGI_STL_INTERNAL_ALLOC_H
+
+#ifndef __ALLOC
+#   define __ALLOC alloc
+#endif
+
+#include <stddef.h>
+#include <string.h>
+
+// The following is just replicated from the conventional SGI alloc.h:
+
+template<class T, class alloc>
+class simple_alloc {
+
+public:
+    static T *allocate(size_t n)
+                { return 0 == n? 0 : (T*) alloc::allocate(n * sizeof (T)); }
+    static T *allocate(void)
+                { return (T*) alloc::allocate(sizeof (T)); }
+    static void deallocate(T *p, size_t n)
+                { if (0 != n) alloc::deallocate(p, n * sizeof (T)); }
+    static void deallocate(T *p)
+                { alloc::deallocate(p, sizeof (T)); }
+};
+
+#include "gc.h"
+
+// The following need to match collector data structures.
+// We can't include gc_priv.h, since that pulls in way too much stuff.
+// This should eventually be factored out into another include file.
+
+extern "C" {
+    extern void ** const GC_objfreelist_ptr;
+    extern void ** const GC_aobjfreelist_ptr;
+    extern void ** const GC_uobjfreelist_ptr;
+    extern void ** const GC_auobjfreelist_ptr;
+
+    extern void GC_incr_words_allocd(size_t words);
+    extern void GC_incr_mem_freed(size_t words);
+
+    extern char * GC_generic_malloc_words_small(size_t word, int kind);
+}
+
+// Object kinds; must match PTRFREE, NORMAL, UNCOLLECTABLE, and
+// AUNCOLLECTABLE in gc_priv.h.
+
+enum { GC_PTRFREE = 0, GC_NORMAL = 1, GC_UNCOLLECTABLE = 2,
+       GC_AUNCOLLECTABLE = 3 };
+
+enum { GC_max_fast_bytes = 255 };
+
+enum { GC_bytes_per_word = sizeof(char *) };
+
+enum { GC_byte_alignment = 8 };
+
+enum { GC_word_alignment = GC_byte_alignment/GC_bytes_per_word };
+
+inline void * &GC_obj_link(void * p)
+{   return *(void **)p;  }
+
+// Compute a number of words >= n+1 bytes.
+// The +1 allows for pointers one past the end.
+inline size_t GC_round_up(size_t n)
+{
+    return ((n + GC_byte_alignment)/GC_byte_alignment)*GC_word_alignment;
+}
+
+// The same but don't allow for extra byte.
+inline size_t GC_round_up_uncollectable(size_t n)
+{
+    return ((n + GC_byte_alignment - 1)/GC_byte_alignment)*GC_word_alignment;
+}
+
+template <int dummy>
+class GC_aux_template {
+public:
+  // File local count of allocated words.  Occasionally this is
+  // added into the global count.  A separate count is necessary since the
+  // real one must be updated with a procedure call.
+  static size_t GC_words_recently_allocd;
+
+  // Same for uncollectable mmory.  Not yet reflected in either
+  // GC_words_recently_allocd or GC_non_gc_bytes.
+  static size_t GC_uncollectable_words_recently_allocd;
+
+  // Similar counter for explicitly deallocated memory.
+  static size_t GC_mem_recently_freed;
+
+  // Again for uncollectable memory.
+  static size_t GC_uncollectable_mem_recently_freed;
+
+  static void * GC_out_of_line_malloc(size_t nwords, int kind);
+};
+
+template <int dummy>
+size_t GC_aux_template<dummy>::GC_words_recently_allocd = 0;
+
+template <int dummy>
+size_t GC_aux_template<dummy>::GC_uncollectable_words_recently_allocd = 0;
+
+template <int dummy>
+size_t GC_aux_template<dummy>::GC_mem_recently_freed = 0;
+
+template <int dummy>
+size_t GC_aux_template<dummy>::GC_uncollectable_mem_recently_freed = 0;
+
+template <int dummy>
+void * GC_aux_template<dummy>::GC_out_of_line_malloc(size_t nwords, int kind)
+{
+    GC_words_recently_allocd += GC_uncollectable_words_recently_allocd;
+    GC_non_gc_bytes +=
+                GC_bytes_per_word * GC_uncollectable_words_recently_allocd;
+    GC_uncollectable_words_recently_allocd = 0;
+
+    GC_mem_recently_freed += GC_uncollectable_mem_recently_freed;
+    GC_non_gc_bytes -= 
+                GC_bytes_per_word * GC_uncollectable_mem_recently_freed;
+    GC_uncollectable_mem_recently_freed = 0;
+
+    GC_incr_words_allocd(GC_words_recently_allocd);
+    GC_words_recently_allocd = 0;
+
+    GC_incr_mem_freed(GC_mem_recently_freed);
+    GC_mem_recently_freed = 0;
+
+    return GC_generic_malloc_words_small(nwords, kind);
+}
+
+typedef GC_aux_template<0> GC_aux;
+
+// A fast, single-threaded, garbage-collected allocator
+// We assume the first word will be immediately overwritten.
+// In this version, deallocation is not a noop, and explicit
+// deallocation is likely to help performance.
+template <int dummy>
+class single_client_gc_alloc_template {
+    public:
+     	static void * allocate(size_t n)
+        {
+	    size_t nwords = GC_round_up(n);
+	    void ** flh;
+	    void * op;
+
+  	    if (n > GC_max_fast_bytes) return GC_malloc(n);
+	    flh = GC_objfreelist_ptr + nwords;
+	    if (0 == (op = *flh)) {
+		return GC_aux::GC_out_of_line_malloc(nwords, GC_NORMAL);
+	    }
+	    *flh = GC_obj_link(op);
+	    GC_aux::GC_words_recently_allocd += nwords;
+	    return op;
+        }
+     	static void * ptr_free_allocate(size_t n)
+        {
+	    size_t nwords = GC_round_up(n);
+	    void ** flh;
+	    void * op;
+
+  	    if (n > GC_max_fast_bytes) return GC_malloc_atomic(n);
+	    flh = GC_aobjfreelist_ptr + nwords;
+	    if (0 == (op = *flh)) {
+		return GC_aux::GC_out_of_line_malloc(nwords, GC_PTRFREE);
+	    }
+	    *flh = GC_obj_link(op);
+	    GC_aux::GC_words_recently_allocd += nwords;
+	    return op;
+        }
+	static void deallocate(void *p, size_t n)
+	{
+            size_t nwords = GC_round_up(n);
+            void ** flh;
+	   
+	    if (n > GC_max_fast_bytes)  {
+		GC_free(p);
+	    } else {
+	        flh = GC_objfreelist_ptr + nwords;
+	        GC_obj_link(p) = *flh;
+		memset((char *)p + GC_bytes_per_word, 0,
+		       GC_bytes_per_word * (nwords - 1));
+	        *flh = p;
+	        GC_aux::GC_mem_recently_freed += nwords;
+	    }
+	}
+	static void ptr_free_deallocate(void *p, size_t n)
+	{
+            size_t nwords = GC_round_up(n);
+            void ** flh;
+	   
+	    if (n > GC_max_fast_bytes) {
+		GC_free(p);
+	    } else {
+	    	flh = GC_aobjfreelist_ptr + nwords;
+	    	GC_obj_link(p) = *flh;
+	    	*flh = p;
+	    	GC_aux::GC_mem_recently_freed += nwords;
+	    }
+	}
+};
+
+typedef single_client_gc_alloc_template<0> single_client_gc_alloc;
+
+// Once more, for uncollectable objects.
+template <int dummy>
+class single_client_alloc_template {
+    public:
+     	static void * allocate(size_t n)
+        {
+	    size_t nwords = GC_round_up_uncollectable(n);
+	    void ** flh;
+	    void * op;
+
+  	    if (n > GC_max_fast_bytes) return GC_malloc_uncollectable(n);
+	    flh = GC_uobjfreelist_ptr + nwords;
+	    if (0 == (op = *flh)) {
+		return GC_aux::GC_out_of_line_malloc(nwords, GC_UNCOLLECTABLE);
+	    }
+	    *flh = GC_obj_link(op);
+	    GC_aux::GC_uncollectable_words_recently_allocd += nwords;
+	    return op;
+        }
+     	static void * ptr_free_allocate(size_t n)
+        {
+	    size_t nwords = GC_round_up_uncollectable(n);
+	    void ** flh;
+	    void * op;
+
+  	    if (n > GC_max_fast_bytes) return GC_malloc_atomic_uncollectable(n);
+	    flh = GC_auobjfreelist_ptr + nwords;
+	    if (0 == (op = *flh)) {
+		return GC_aux::GC_out_of_line_malloc(nwords, GC_AUNCOLLECTABLE);
+	    }
+	    *flh = GC_obj_link(op);
+	    GC_aux::GC_uncollectable_words_recently_allocd += nwords;
+	    return op;
+        }
+	static void deallocate(void *p, size_t n)
+	{
+            size_t nwords = GC_round_up_uncollectable(n);
+            void ** flh;
+	   
+	    if (n > GC_max_fast_bytes)  {
+		GC_free(p);
+	    } else {
+	        flh = GC_uobjfreelist_ptr + nwords;
+	        GC_obj_link(p) = *flh;
+	        *flh = p;
+	        GC_aux::GC_uncollectable_mem_recently_freed += nwords;
+	    }
+	}
+	static void ptr_free_deallocate(void *p, size_t n)
+	{
+            size_t nwords = GC_round_up_uncollectable(n);
+            void ** flh;
+	   
+	    if (n > GC_max_fast_bytes) {
+		GC_free(p);
+	    } else {
+	    	flh = GC_auobjfreelist_ptr + nwords;
+	    	GC_obj_link(p) = *flh;
+	    	*flh = p;
+	    	GC_aux::GC_uncollectable_mem_recently_freed += nwords;
+	    }
+	}
+};
+
+typedef single_client_alloc_template<0> single_client_alloc;
+
+template < int dummy >
+class gc_alloc_template {
+    public:
+     	static void * allocate(size_t n) { return GC_malloc(n); }
+     	static void * ptr_free_allocate(size_t n)
+		{ return GC_malloc_atomic(n); }
+	static void deallocate(void *, size_t) { }
+	static void ptr_free_deallocate(void *, size_t) { }
+};
+
+typedef gc_alloc_template < 0 > gc_alloc;
+
+template < int dummy >
+class alloc_template {
+    public:
+     	static void * allocate(size_t n) { return GC_malloc_uncollectable(n); }
+     	static void * ptr_free_allocate(size_t n)
+		{ return GC_malloc_atomic_uncollectable(n); }
+	static void deallocate(void *p, size_t) { GC_free(p); }
+	static void ptr_free_deallocate(void *p, size_t) { GC_free(p); }
+};
+
+typedef alloc_template < 0 > alloc;
+
+#ifdef _SGI_SOURCE
+
+// We want to specialize simple_alloc so that it does the right thing
+// for all pointerfree types.  At the moment there is no portable way to
+// even approximate that.  The following approximation should work for
+// SGI compilers, and perhaps some others.
+
+# define __GC_SPECIALIZE(T,alloc) \
+class simple_alloc<T, alloc> { \
+public: \
+    static T *allocate(size_t n) \
+	{ return 0 == n? 0 : \
+			 (T*) alloc::ptr_free_allocate(n * sizeof (T)); } \
+    static T *allocate(void) \
+	{ return (T*) alloc::ptr_free_allocate(sizeof (T)); } \
+    static void deallocate(T *p, size_t n) \
+	{ if (0 != n) alloc::ptr_free_deallocate(p, n * sizeof (T)); } \
+    static void deallocate(T *p) \
+	{ alloc::ptr_free_deallocate(p, sizeof (T)); } \
+};
+
+__GC_SPECIALIZE(char, gc_alloc)
+__GC_SPECIALIZE(int, gc_alloc)
+__GC_SPECIALIZE(unsigned, gc_alloc)
+__GC_SPECIALIZE(float, gc_alloc)
+__GC_SPECIALIZE(double, gc_alloc)
+
+__GC_SPECIALIZE(char, alloc)
+__GC_SPECIALIZE(int, alloc)
+__GC_SPECIALIZE(unsigned, alloc)
+__GC_SPECIALIZE(float, alloc)
+__GC_SPECIALIZE(double, alloc)
+
+__GC_SPECIALIZE(char, single_client_gc_alloc)
+__GC_SPECIALIZE(int, single_client_gc_alloc)
+__GC_SPECIALIZE(unsigned, single_client_gc_alloc)
+__GC_SPECIALIZE(float, single_client_gc_alloc)
+__GC_SPECIALIZE(double, single_client_gc_alloc)
+
+__GC_SPECIALIZE(char, single_client_alloc)
+__GC_SPECIALIZE(int, single_client_alloc)
+__GC_SPECIALIZE(unsigned, single_client_alloc)
+__GC_SPECIALIZE(float, single_client_alloc)
+__GC_SPECIALIZE(double, single_client_alloc)
+
+#ifdef __STL_USE_STD_ALLOCATORS
+
+???copy stuff from stl_alloc.h or remove it to a different file ???
+
+#endif /* __STL_USE_STD_ALLOCATORS */
+
+#endif /* _SGI_SOURCE */
+
+#endif /* GC_ALLOC_H */