+++ /dev/null
-/*
- * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
- * Copyright (c) 2001 by Hewlett-Packard Company. 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 contains interfaces to the GC marker that are likely to be useful to
- * clients that provide detailed heap layout information to the collector.
- * This interface should not be used by normal C or C++ clients.
- * It will be useful to runtimes for other languages.
- *
- * Note that this file is not "namespace-clean", i.e. it introduces names
- * not prefixed with GC_, which may collide with the client's names. It
- * should be included only in those few places that directly provide
- * information to the collector.
- */
-#ifndef GC_MARK_H
-# define GC_MARK_H
-
-# ifndef GC_H
-# include "gc.h"
-# endif
-
-/* A client supplied mark procedure. Returns new mark stack pointer. */
-/* Primary effect should be to push new entries on the mark stack. */
-/* Mark stack pointer values are passed and returned explicitly. */
-/* Global variables decribing mark stack are not necessarily valid. */
-/* (This usually saves a few cycles by keeping things in registers.) */
-/* Assumed to scan about GC_PROC_BYTES on average. If it needs to do */
-/* much more work than that, it should do it in smaller pieces by */
-/* pushing itself back on the mark stack. */
-/* Note that it should always do some work (defined as marking some */
-/* objects) before pushing more than one entry on the mark stack. */
-/* This is required to ensure termination in the event of mark stack */
-/* overflows. */
-/* This procedure is always called with at least one empty entry on the */
-/* mark stack. */
-/* Currently we require that mark procedures look for pointers in a */
-/* subset of the places the conservative marker would. It must be safe */
-/* to invoke the normal mark procedure instead. */
-/* WARNING: Such a mark procedure may be invoked on an unused object */
-/* residing on a free list. Such objects are cleared, except for a */
-/* free list link field in the first word. Thus mark procedures may */
-/* not count on the presence of a type descriptor, and must handle this */
-/* case correctly somehow. */
-# define GC_PROC_BYTES 100
-struct GC_ms_entry;
-typedef struct GC_ms_entry * (*GC_mark_proc) GC_PROTO((
- GC_word * addr, struct GC_ms_entry * mark_stack_ptr,
- struct GC_ms_entry * mark_stack_limit, GC_word env));
-
-# define GC_LOG_MAX_MARK_PROCS 6
-# define GC_MAX_MARK_PROCS (1 << GC_LOG_MAX_MARK_PROCS)
-
-/* In a few cases it's necessary to assign statically known indices to */
-/* certain mark procs. Thus we reserve a few for well known clients. */
-/* (This is necessary if mark descriptors are compiler generated.) */
-#define GC_RESERVED_MARK_PROCS 8
-# define GC_GCJ_RESERVED_MARK_PROC_INDEX 0
-
-/* Object descriptors on mark stack or in objects. Low order two */
-/* bits are tags distinguishing among the following 4 possibilities */
-/* for the high order 30 bits. */
-#define GC_DS_TAG_BITS 2
-#define GC_DS_TAGS ((1 << GC_DS_TAG_BITS) - 1)
-#define GC_DS_LENGTH 0 /* The entire word is a length in bytes that */
- /* must be a multiple of 4. */
-#define GC_DS_BITMAP 1 /* 30 (62) bits are a bitmap describing pointer */
- /* fields. The msb is 1 iff the first word */
- /* is a pointer. */
- /* (This unconventional ordering sometimes */
- /* makes the marker slightly faster.) */
- /* Zeroes indicate definite nonpointers. Ones */
- /* indicate possible pointers. */
- /* Only usable if pointers are word aligned. */
-#define GC_DS_PROC 2
- /* The objects referenced by this object can be */
- /* pushed on the mark stack by invoking */
- /* PROC(descr). ENV(descr) is passed as the */
- /* last argument. */
-# define GC_MAKE_PROC(proc_index, env) \
- (((((env) << GC_LOG_MAX_MARK_PROCS) \
- | (proc_index)) << GC_DS_TAG_BITS) | GC_DS_PROC)
-#define GC_DS_PER_OBJECT 3 /* The real descriptor is at the */
- /* byte displacement from the beginning of the */
- /* object given by descr & ~DS_TAGS */
- /* If the descriptor is negative, the real */
- /* descriptor is at (*<object_start>) - */
- /* (descr & ~DS_TAGS) - GC_INDIR_PER_OBJ_BIAS */
- /* The latter alternative can be used if each */
- /* object contains a type descriptor in the */
- /* first word. */
- /* Note that in multithreaded environments */
- /* per object descriptors maust be located in */
- /* either the first two or last two words of */
- /* the object, since only those are guaranteed */
- /* to be cleared while the allocation lock is */
- /* held. */
-#define GC_INDIR_PER_OBJ_BIAS 0x10
-
-extern GC_PTR GC_least_plausible_heap_addr;
-extern GC_PTR GC_greatest_plausible_heap_addr;
- /* Bounds on the heap. Guaranteed valid */
- /* Likely to include future heap expansion. */
-
-/* Handle nested references in a custom mark procedure. */
-/* Check if obj is a valid object. If so, ensure that it is marked. */
-/* If it was not previously marked, push its contents onto the mark */
-/* stack for future scanning. The object will then be scanned using */
-/* its mark descriptor. */
-/* Returns the new mark stack pointer. */
-/* Handles mark stack overflows correctly. */
-/* Since this marks first, it makes progress even if there are mark */
-/* stack overflows. */
-/* Src is the address of the pointer to obj, which is used only */
-/* for back pointer-based heap debugging. */
-/* It is strongly recommended that most objects be handled without mark */
-/* procedures, e.g. with bitmap descriptors, and that mark procedures */
-/* be reserved for exceptional cases. That will ensure that */
-/* performance of this call is not extremely performance critical. */
-/* (Otherwise we would need to inline GC_mark_and_push completely, */
-/* which would tie the client code to a fixed colllector version.) */
-struct GC_ms_entry *GC_mark_and_push
- GC_PROTO((GC_PTR obj,
- struct GC_ms_entry * mark_stack_ptr,
- struct GC_ms_entry * mark_stack_limit, GC_PTR *src));
-
-#define GC_MARK_AND_PUSH(obj, msp, lim, src) \
- (((GC_word)obj >= (GC_word)GC_least_plausible_heap_addr && \
- (GC_word)obj <= (GC_word)GC_greatest_plausible_heap_addr)? \
- GC_mark_and_push(obj, msp, lim, src) : \
- msp)
-
-#endif /* GC_MARK_H */
-
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