/*
* 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 revision of gc_alloc.h for SGI STL versions > 3.0
// Unlike earlier versions, it supplements the standard "alloc.h"
// instead of replacing it.
//
// This is sloppy about variable names used in header files.
// It also doesn't yet understand the new header file names or
// namespaces.
//
// This assumes the collector has been compiled with -DATOMIC_UNCOLLECTABLE.
// The user should also consider -DREDIRECT_MALLOC=GC_uncollectable_malloc,
// to ensure that object allocated through malloc are traced.
//
// 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.
//
// Unlike its predecessor, this one simply defines
// gc_alloc
// single_client_gc_alloc
// traceable_alloc
// single_client_traceable_alloc
//
// It does not redefine alloc. Nor does it change the default allocator,
// though the user may wish to do so. (The argument against changing
// the default allocator is that it may introduce subtle link compatibility
// problems. The argument for changing it is that the usual default
// allocator is usually a very bad choice for a garbage collected environment.)
//
// This code assumes that the collector itself has been compiled with a
// compiler that defines __STDC__ .
//
#ifndef GC_ALLOC_H
#include "gc.h"
#include <stack> // A more portable way to get stl_alloc.h .
#define GC_ALLOC_H
#include <stddef.h>
#include <string.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_traceable_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_traceable_alloc_template<0> single_client_traceable_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 traceable_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 traceable_alloc_template < 0 > traceable_alloc;
// 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 recent versions of g++.
# 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)); } \
};
__STL_BEGIN_NAMESPACE
__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, traceable_alloc)
__GC_SPECIALIZE(int, traceable_alloc)
__GC_SPECIALIZE(unsigned, traceable_alloc)
__GC_SPECIALIZE(float, traceable_alloc)
__GC_SPECIALIZE(double, traceable_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_traceable_alloc)
__GC_SPECIALIZE(int, single_client_traceable_alloc)
__GC_SPECIALIZE(unsigned, single_client_traceable_alloc)
__GC_SPECIALIZE(float, single_client_traceable_alloc)
__GC_SPECIALIZE(double, single_client_traceable_alloc)
__STL_END_NAMESPACE
#ifdef __STL_USE_STD_ALLOCATORS
__STL_BEGIN_NAMESPACE
template <class _T>
struct _Alloc_traits<_T, gc_alloc >
{
static const bool _S_instanceless = true;
typedef simple_alloc<_T, gc_alloc > _Alloc_type;
typedef __allocator<_T, gc_alloc > allocator_type;
};
inline bool operator==(const gc_alloc&,
const gc_alloc&)
{
return true;
}
inline bool operator!=(const gc_alloc&,
const gc_alloc&)
{
return false;
}
template <class _T>
struct _Alloc_traits<_T, single_client_gc_alloc >
{
static const bool _S_instanceless = true;
typedef simple_alloc<_T, single_client_gc_alloc > _Alloc_type;
typedef __allocator<_T, single_client_gc_alloc > allocator_type;
};
inline bool operator==(const single_client_gc_alloc&,
const single_client_gc_alloc&)
{
return true;
}
inline bool operator!=(const single_client_gc_alloc&,
const single_client_gc_alloc&)
{
return false;
}
template <class _T>
struct _Alloc_traits<_T, traceable_alloc >
{
static const bool _S_instanceless = true;
typedef simple_alloc<_T, traceable_alloc > _Alloc_type;
typedef __allocator<_T, traceable_alloc > allocator_type;
};
inline bool operator==(const traceable_alloc&,
const traceable_alloc&)
{
return true;
}
inline bool operator!=(const traceable_alloc&,
const traceable_alloc&)
{
return false;
}
template <class _T>
struct _Alloc_traits<_T, single_client_traceable_alloc >
{
static const bool _S_instanceless = true;
typedef simple_alloc<_T, single_client_traceable_alloc > _Alloc_type;
typedef __allocator<_T, single_client_traceable_alloc > allocator_type;
};
inline bool operator==(const single_client_traceable_alloc&,
const single_client_traceable_alloc&)
{
return true;
}
inline bool operator!=(const single_client_traceable_alloc&,
const single_client_traceable_alloc&)
{
return false;
}
__STL_END_NAMESPACE
#endif /* __STL_USE_STD_ALLOCATORS */
#endif /* GC_ALLOC_H */
