mirror of
https://github.com/autc04/Retro68.git
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1818 lines
55 KiB
C
1818 lines
55 KiB
C
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/*
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* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
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* Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved.
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* Copyright (c) 2000 by Hewlett-Packard Company. All rights reserved.
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*
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* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
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* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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*
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* Permission is hereby granted to use or copy this program
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* for any purpose, provided the above notices are retained on all copies.
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* Permission to modify the code and to distribute modified code is granted,
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* provided the above notices are retained, and a notice that the code was
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* modified is included with the above copyright notice.
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*
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*/
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# include <stdio.h>
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# include "private/gc_pmark.h"
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#if defined(MSWIN32) && defined(__GNUC__)
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# include <excpt.h>
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#endif
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/* We put this here to minimize the risk of inlining. */
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/*VARARGS*/
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#ifdef __WATCOMC__
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void GC_noop(void *p, ...) {}
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#else
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void GC_noop() {}
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#endif
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/* Single argument version, robust against whole program analysis. */
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void GC_noop1(x)
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word x;
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{
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static VOLATILE word sink;
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sink = x;
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}
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/* mark_proc GC_mark_procs[MAX_MARK_PROCS] = {0} -- declared in gc_priv.h */
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word GC_n_mark_procs = GC_RESERVED_MARK_PROCS;
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/* Initialize GC_obj_kinds properly and standard free lists properly. */
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/* This must be done statically since they may be accessed before */
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/* GC_init is called. */
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/* It's done here, since we need to deal with mark descriptors. */
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struct obj_kind GC_obj_kinds[MAXOBJKINDS] = {
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/* PTRFREE */ { &GC_aobjfreelist[0], 0 /* filled in dynamically */,
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0 | GC_DS_LENGTH, FALSE, FALSE },
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/* NORMAL */ { &GC_objfreelist[0], 0,
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0 | GC_DS_LENGTH, /* Adjusted in GC_init_inner for EXTRA_BYTES */
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TRUE /* add length to descr */, TRUE },
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/* UNCOLLECTABLE */
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{ &GC_uobjfreelist[0], 0,
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0 | GC_DS_LENGTH, TRUE /* add length to descr */, TRUE },
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# ifdef ATOMIC_UNCOLLECTABLE
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/* AUNCOLLECTABLE */
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{ &GC_auobjfreelist[0], 0,
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0 | GC_DS_LENGTH, FALSE /* add length to descr */, FALSE },
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# endif
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# ifdef STUBBORN_ALLOC
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/*STUBBORN*/ { &GC_sobjfreelist[0], 0,
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0 | GC_DS_LENGTH, TRUE /* add length to descr */, TRUE },
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# endif
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};
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# ifdef ATOMIC_UNCOLLECTABLE
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# ifdef STUBBORN_ALLOC
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int GC_n_kinds = 5;
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# else
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int GC_n_kinds = 4;
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# endif
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# else
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# ifdef STUBBORN_ALLOC
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int GC_n_kinds = 4;
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# else
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int GC_n_kinds = 3;
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# endif
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# endif
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# ifndef INITIAL_MARK_STACK_SIZE
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# define INITIAL_MARK_STACK_SIZE (1*HBLKSIZE)
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/* INITIAL_MARK_STACK_SIZE * sizeof(mse) should be a */
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/* multiple of HBLKSIZE. */
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/* The incremental collector actually likes a larger */
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/* size, since it want to push all marked dirty objs */
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/* before marking anything new. Currently we let it */
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/* grow dynamically. */
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# endif
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/*
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* Limits of stack for GC_mark routine.
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* All ranges between GC_mark_stack(incl.) and GC_mark_stack_top(incl.) still
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* need to be marked from.
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*/
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word GC_n_rescuing_pages; /* Number of dirty pages we marked from */
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/* excludes ptrfree pages, etc. */
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mse * GC_mark_stack;
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mse * GC_mark_stack_limit;
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word GC_mark_stack_size = 0;
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#ifdef PARALLEL_MARK
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mse * VOLATILE GC_mark_stack_top;
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#else
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mse * GC_mark_stack_top;
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#endif
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static struct hblk * scan_ptr;
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mark_state_t GC_mark_state = MS_NONE;
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GC_bool GC_mark_stack_too_small = FALSE;
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GC_bool GC_objects_are_marked = FALSE; /* Are there collectable marked */
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/* objects in the heap? */
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/* Is a collection in progress? Note that this can return true in the */
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/* nonincremental case, if a collection has been abandoned and the */
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/* mark state is now MS_INVALID. */
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GC_bool GC_collection_in_progress()
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{
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return(GC_mark_state != MS_NONE);
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}
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/* clear all mark bits in the header */
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void GC_clear_hdr_marks(hhdr)
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register hdr * hhdr;
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{
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# ifdef USE_MARK_BYTES
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BZERO(hhdr -> hb_marks, MARK_BITS_SZ);
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# else
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BZERO(hhdr -> hb_marks, MARK_BITS_SZ*sizeof(word));
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# endif
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}
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/* Set all mark bits in the header. Used for uncollectable blocks. */
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void GC_set_hdr_marks(hhdr)
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register hdr * hhdr;
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{
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register int i;
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for (i = 0; i < MARK_BITS_SZ; ++i) {
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# ifdef USE_MARK_BYTES
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hhdr -> hb_marks[i] = 1;
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# else
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hhdr -> hb_marks[i] = ONES;
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# endif
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}
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}
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/*
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* Clear all mark bits associated with block h.
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*/
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/*ARGSUSED*/
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# if defined(__STDC__) || defined(__cplusplus)
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static void clear_marks_for_block(struct hblk *h, word dummy)
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# else
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static void clear_marks_for_block(h, dummy)
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struct hblk *h;
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word dummy;
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# endif
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{
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register hdr * hhdr = HDR(h);
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if (IS_UNCOLLECTABLE(hhdr -> hb_obj_kind)) return;
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/* Mark bit for these is cleared only once the object is */
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/* explicitly deallocated. This either frees the block, or */
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/* the bit is cleared once the object is on the free list. */
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GC_clear_hdr_marks(hhdr);
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}
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/* Slow but general routines for setting/clearing/asking about mark bits */
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void GC_set_mark_bit(p)
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ptr_t p;
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{
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register struct hblk *h = HBLKPTR(p);
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register hdr * hhdr = HDR(h);
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register int word_no = (word *)p - (word *)h;
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set_mark_bit_from_hdr(hhdr, word_no);
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}
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void GC_clear_mark_bit(p)
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ptr_t p;
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{
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register struct hblk *h = HBLKPTR(p);
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register hdr * hhdr = HDR(h);
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register int word_no = (word *)p - (word *)h;
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clear_mark_bit_from_hdr(hhdr, word_no);
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}
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GC_bool GC_is_marked(p)
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ptr_t p;
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{
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register struct hblk *h = HBLKPTR(p);
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register hdr * hhdr = HDR(h);
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register int word_no = (word *)p - (word *)h;
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return(mark_bit_from_hdr(hhdr, word_no));
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}
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/*
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* Clear mark bits in all allocated heap blocks. This invalidates
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* the marker invariant, and sets GC_mark_state to reflect this.
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* (This implicitly starts marking to reestablish the invariant.)
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*/
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void GC_clear_marks()
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{
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GC_apply_to_all_blocks(clear_marks_for_block, (word)0);
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GC_objects_are_marked = FALSE;
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GC_mark_state = MS_INVALID;
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scan_ptr = 0;
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# ifdef GATHERSTATS
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/* Counters reflect currently marked objects: reset here */
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GC_composite_in_use = 0;
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GC_atomic_in_use = 0;
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# endif
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}
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/* Initiate a garbage collection. Initiates a full collection if the */
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/* mark state is invalid. */
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/*ARGSUSED*/
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void GC_initiate_gc()
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{
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if (GC_dirty_maintained) GC_read_dirty();
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# ifdef STUBBORN_ALLOC
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GC_read_changed();
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# endif
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# ifdef CHECKSUMS
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{
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extern void GC_check_dirty();
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if (GC_dirty_maintained) GC_check_dirty();
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}
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# endif
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GC_n_rescuing_pages = 0;
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if (GC_mark_state == MS_NONE) {
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GC_mark_state = MS_PUSH_RESCUERS;
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} else if (GC_mark_state != MS_INVALID) {
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ABORT("unexpected state");
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} /* else this is really a full collection, and mark */
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/* bits are invalid. */
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scan_ptr = 0;
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}
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static void alloc_mark_stack();
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/* Perform a small amount of marking. */
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/* We try to touch roughly a page of memory. */
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/* Return TRUE if we just finished a mark phase. */
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/* Cold_gc_frame is an address inside a GC frame that */
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/* remains valid until all marking is complete. */
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/* A zero value indicates that it's OK to miss some */
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/* register values. */
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/* We hold the allocation lock. In the case of */
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/* incremental collection, the world may not be stopped.*/
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#ifdef MSWIN32
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/* For win32, this is called after we establish a structured */
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/* exception handler, in case Windows unmaps one of our root */
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/* segments. See below. In either case, we acquire the */
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/* allocator lock long before we get here. */
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GC_bool GC_mark_some_inner(cold_gc_frame)
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ptr_t cold_gc_frame;
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#else
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GC_bool GC_mark_some(cold_gc_frame)
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ptr_t cold_gc_frame;
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#endif
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{
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switch(GC_mark_state) {
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case MS_NONE:
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return(FALSE);
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case MS_PUSH_RESCUERS:
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if (GC_mark_stack_top
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>= GC_mark_stack_limit - INITIAL_MARK_STACK_SIZE/2) {
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/* Go ahead and mark, even though that might cause us to */
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/* see more marked dirty objects later on. Avoid this */
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/* in the future. */
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GC_mark_stack_too_small = TRUE;
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MARK_FROM_MARK_STACK();
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return(FALSE);
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} else {
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scan_ptr = GC_push_next_marked_dirty(scan_ptr);
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if (scan_ptr == 0) {
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# ifdef CONDPRINT
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if (GC_print_stats) {
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GC_printf1("Marked from %lu dirty pages\n",
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(unsigned long)GC_n_rescuing_pages);
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}
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# endif
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GC_push_roots(FALSE, cold_gc_frame);
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GC_objects_are_marked = TRUE;
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if (GC_mark_state != MS_INVALID) {
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GC_mark_state = MS_ROOTS_PUSHED;
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}
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}
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}
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return(FALSE);
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case MS_PUSH_UNCOLLECTABLE:
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if (GC_mark_stack_top
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>= GC_mark_stack + GC_mark_stack_size/4) {
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# ifdef PARALLEL_MARK
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/* Avoid this, since we don't parallelize the marker */
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/* here. */
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if (GC_parallel) GC_mark_stack_too_small = TRUE;
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# endif
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MARK_FROM_MARK_STACK();
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return(FALSE);
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} else {
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scan_ptr = GC_push_next_marked_uncollectable(scan_ptr);
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if (scan_ptr == 0) {
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GC_push_roots(TRUE, cold_gc_frame);
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GC_objects_are_marked = TRUE;
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if (GC_mark_state != MS_INVALID) {
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GC_mark_state = MS_ROOTS_PUSHED;
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}
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}
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}
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return(FALSE);
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case MS_ROOTS_PUSHED:
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# ifdef PARALLEL_MARK
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/* In the incremental GC case, this currently doesn't */
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/* quite do the right thing, since it runs to */
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/* completion. On the other hand, starting a */
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/* parallel marker is expensive, so perhaps it is */
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/* the right thing? */
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/* Eventually, incremental marking should run */
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/* asynchronously in multiple threads, without grabbing */
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/* the allocation lock. */
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if (GC_parallel) {
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GC_do_parallel_mark();
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GC_ASSERT(GC_mark_stack_top < GC_first_nonempty);
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GC_mark_stack_top = GC_mark_stack - 1;
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if (GC_mark_stack_too_small) {
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alloc_mark_stack(2*GC_mark_stack_size);
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}
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if (GC_mark_state == MS_ROOTS_PUSHED) {
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GC_mark_state = MS_NONE;
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return(TRUE);
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} else {
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return(FALSE);
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}
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}
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# endif
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if (GC_mark_stack_top >= GC_mark_stack) {
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MARK_FROM_MARK_STACK();
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return(FALSE);
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} else {
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GC_mark_state = MS_NONE;
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if (GC_mark_stack_too_small) {
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alloc_mark_stack(2*GC_mark_stack_size);
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}
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return(TRUE);
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}
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case MS_INVALID:
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case MS_PARTIALLY_INVALID:
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if (!GC_objects_are_marked) {
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GC_mark_state = MS_PUSH_UNCOLLECTABLE;
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return(FALSE);
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}
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if (GC_mark_stack_top >= GC_mark_stack) {
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MARK_FROM_MARK_STACK();
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return(FALSE);
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}
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if (scan_ptr == 0 && GC_mark_state == MS_INVALID) {
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/* About to start a heap scan for marked objects. */
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/* Mark stack is empty. OK to reallocate. */
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if (GC_mark_stack_too_small) {
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alloc_mark_stack(2*GC_mark_stack_size);
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}
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GC_mark_state = MS_PARTIALLY_INVALID;
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}
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scan_ptr = GC_push_next_marked(scan_ptr);
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if (scan_ptr == 0 && GC_mark_state == MS_PARTIALLY_INVALID) {
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GC_push_roots(TRUE, cold_gc_frame);
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GC_objects_are_marked = TRUE;
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if (GC_mark_state != MS_INVALID) {
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GC_mark_state = MS_ROOTS_PUSHED;
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}
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}
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return(FALSE);
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default:
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ABORT("GC_mark_some: bad state");
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return(FALSE);
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}
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}
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#ifdef MSWIN32
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# ifdef __GNUC__
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typedef struct {
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EXCEPTION_REGISTRATION ex_reg;
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void *alt_path;
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} ext_ex_regn;
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static EXCEPTION_DISPOSITION mark_ex_handler(
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struct _EXCEPTION_RECORD *ex_rec,
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void *est_frame,
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struct _CONTEXT *context,
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void *disp_ctxt)
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{
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if (ex_rec->ExceptionCode == STATUS_ACCESS_VIOLATION) {
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ext_ex_regn *xer = (ext_ex_regn *)est_frame;
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/* Unwind from the inner function assuming the standard */
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/* function prologue. */
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/* Assumes code has not been compiled with */
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/* -fomit-frame-pointer. */
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context->Esp = context->Ebp;
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context->Ebp = *((DWORD *)context->Esp);
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context->Esp = context->Esp - 8;
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/* Resume execution at the "real" handler within the */
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/* wrapper function. */
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context->Eip = (DWORD )(xer->alt_path);
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return ExceptionContinueExecution;
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} else {
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return ExceptionContinueSearch;
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}
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}
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# endif /* __GNUC__ */
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|
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GC_bool GC_mark_some(cold_gc_frame)
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ptr_t cold_gc_frame;
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{
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GC_bool ret_val;
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|
# ifndef __GNUC__
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/* Windows 98 appears to asynchronously create and remove */
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/* writable memory mappings, for reasons we haven't yet */
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/* understood. Since we look for writable regions to */
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/* determine the root set, we may try to mark from an */
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/* address range that disappeared since we started the */
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/* collection. Thus we have to recover from faults here. */
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/* This code does not appear to be necessary for Windows */
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/* 95/NT/2000. Note that this code should never generate */
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/* an incremental GC write fault. */
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__try {
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# else /* __GNUC__ */
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/* Manually install an exception handler since GCC does */
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/* not yet support Structured Exception Handling (SEH) on */
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/* Win32. */
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ext_ex_regn er;
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er.alt_path = &&handle_ex;
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er.ex_reg.handler = mark_ex_handler;
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asm volatile ("movl %%fs:0, %0" : "=r" (er.ex_reg.prev));
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asm volatile ("movl %0, %%fs:0" : : "r" (&er));
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# endif /* __GNUC__ */
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ret_val = GC_mark_some_inner(cold_gc_frame);
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|
# ifndef __GNUC__
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|
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|
} __except (GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ?
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|
EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
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# else /* __GNUC__ */
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/* Prevent GCC from considering the following code unreachable */
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/* and thus eliminating it. */
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if (er.alt_path != 0)
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goto rm_handler;
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handle_ex:
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/* Execution resumes from here on an access violation. */
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# endif /* __GNUC__ */
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|
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# ifdef CONDPRINT
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if (GC_print_stats) {
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GC_printf0("Caught ACCESS_VIOLATION in marker. "
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"Memory mapping disappeared.\n");
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}
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# endif /* CONDPRINT */
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/* We have bad roots on the stack. Discard mark stack. */
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/* Rescan from marked objects. Redetermine roots. */
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GC_invalidate_mark_state();
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scan_ptr = 0;
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ret_val = FALSE;
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# ifndef __GNUC__
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}
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# else /* __GNUC__ */
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rm_handler:
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/* Uninstall the exception handler */
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|
asm volatile ("mov %0, %%fs:0" : : "r" (er.ex_reg.prev));
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# endif /* __GNUC__ */
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return ret_val;
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}
|
|
#endif /* MSWIN32 */
|
|
|
|
|
|
GC_bool GC_mark_stack_empty()
|
|
{
|
|
return(GC_mark_stack_top < GC_mark_stack);
|
|
}
|
|
|
|
#ifdef PROF_MARKER
|
|
word GC_prof_array[10];
|
|
# define PROF(n) GC_prof_array[n]++
|
|
#else
|
|
# define PROF(n)
|
|
#endif
|
|
|
|
/* Given a pointer to someplace other than a small object page or the */
|
|
/* first page of a large object, either: */
|
|
/* - return a pointer to somewhere in the first page of the large */
|
|
/* object, if current points to a large object. */
|
|
/* In this case *hhdr is replaced with a pointer to the header */
|
|
/* for the large object. */
|
|
/* - just return current if it does not point to a large object. */
|
|
/*ARGSUSED*/
|
|
ptr_t GC_find_start(current, hhdr, new_hdr_p)
|
|
register ptr_t current;
|
|
register hdr *hhdr, **new_hdr_p;
|
|
{
|
|
if (GC_all_interior_pointers) {
|
|
if (hhdr != 0) {
|
|
register ptr_t orig = current;
|
|
|
|
current = (ptr_t)HBLKPTR(current);
|
|
do {
|
|
current = current - HBLKSIZE*(word)hhdr;
|
|
hhdr = HDR(current);
|
|
} while(IS_FORWARDING_ADDR_OR_NIL(hhdr));
|
|
/* current points to near the start of the large object */
|
|
if (hhdr -> hb_flags & IGNORE_OFF_PAGE) return(orig);
|
|
if ((word *)orig - (word *)current
|
|
>= (ptrdiff_t)(hhdr->hb_sz)) {
|
|
/* Pointer past the end of the block */
|
|
return(orig);
|
|
}
|
|
*new_hdr_p = hhdr;
|
|
return(current);
|
|
} else {
|
|
return(current);
|
|
}
|
|
} else {
|
|
return(current);
|
|
}
|
|
}
|
|
|
|
void GC_invalidate_mark_state()
|
|
{
|
|
GC_mark_state = MS_INVALID;
|
|
GC_mark_stack_top = GC_mark_stack-1;
|
|
}
|
|
|
|
mse * GC_signal_mark_stack_overflow(msp)
|
|
mse * msp;
|
|
{
|
|
GC_mark_state = MS_INVALID;
|
|
GC_mark_stack_too_small = TRUE;
|
|
# ifdef CONDPRINT
|
|
if (GC_print_stats) {
|
|
GC_printf1("Mark stack overflow; current size = %lu entries\n",
|
|
GC_mark_stack_size);
|
|
}
|
|
# endif
|
|
return(msp - GC_MARK_STACK_DISCARDS);
|
|
}
|
|
|
|
/*
|
|
* Mark objects pointed to by the regions described by
|
|
* mark stack entries between GC_mark_stack and GC_mark_stack_top,
|
|
* inclusive. Assumes the upper limit of a mark stack entry
|
|
* is never 0. A mark stack entry never has size 0.
|
|
* We try to traverse on the order of a hblk of memory before we return.
|
|
* Caller is responsible for calling this until the mark stack is empty.
|
|
* Note that this is the most performance critical routine in the
|
|
* collector. Hence it contains all sorts of ugly hacks to speed
|
|
* things up. In particular, we avoid procedure calls on the common
|
|
* path, we take advantage of peculiarities of the mark descriptor
|
|
* encoding, we optionally maintain a cache for the block address to
|
|
* header mapping, we prefetch when an object is "grayed", etc.
|
|
*/
|
|
mse * GC_mark_from(mark_stack_top, mark_stack, mark_stack_limit)
|
|
mse * mark_stack_top;
|
|
mse * mark_stack;
|
|
mse * mark_stack_limit;
|
|
{
|
|
int credit = HBLKSIZE; /* Remaining credit for marking work */
|
|
register word * current_p; /* Pointer to current candidate ptr. */
|
|
register word current; /* Candidate pointer. */
|
|
register word * limit; /* (Incl) limit of current candidate */
|
|
/* range */
|
|
register word descr;
|
|
register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
|
|
register ptr_t least_ha = GC_least_plausible_heap_addr;
|
|
DECLARE_HDR_CACHE;
|
|
|
|
# define SPLIT_RANGE_WORDS 128 /* Must be power of 2. */
|
|
|
|
GC_objects_are_marked = TRUE;
|
|
INIT_HDR_CACHE;
|
|
# ifdef OS2 /* Use untweaked version to circumvent compiler problem */
|
|
while (mark_stack_top >= mark_stack && credit >= 0) {
|
|
# else
|
|
while ((((ptr_t)mark_stack_top - (ptr_t)mark_stack) | credit)
|
|
>= 0) {
|
|
# endif
|
|
current_p = mark_stack_top -> mse_start;
|
|
descr = mark_stack_top -> mse_descr;
|
|
retry:
|
|
/* current_p and descr describe the current object. */
|
|
/* *mark_stack_top is vacant. */
|
|
/* The following is 0 only for small objects described by a simple */
|
|
/* length descriptor. For many applications this is the common */
|
|
/* case, so we try to detect it quickly. */
|
|
if (descr & ((~(WORDS_TO_BYTES(SPLIT_RANGE_WORDS) - 1)) | GC_DS_TAGS)) {
|
|
word tag = descr & GC_DS_TAGS;
|
|
|
|
switch(tag) {
|
|
case GC_DS_LENGTH:
|
|
/* Large length. */
|
|
/* Process part of the range to avoid pushing too much on the */
|
|
/* stack. */
|
|
GC_ASSERT(descr < (word)GC_greatest_plausible_heap_addr
|
|
- (word)GC_least_plausible_heap_addr);
|
|
# ifdef PARALLEL_MARK
|
|
# define SHARE_BYTES 2048
|
|
if (descr > SHARE_BYTES && GC_parallel
|
|
&& mark_stack_top < mark_stack_limit - 1) {
|
|
int new_size = (descr/2) & ~(sizeof(word)-1);
|
|
mark_stack_top -> mse_start = current_p;
|
|
mark_stack_top -> mse_descr = new_size + sizeof(word);
|
|
/* makes sure we handle */
|
|
/* misaligned pointers. */
|
|
mark_stack_top++;
|
|
current_p = (word *) ((char *)current_p + new_size);
|
|
descr -= new_size;
|
|
goto retry;
|
|
}
|
|
# endif /* PARALLEL_MARK */
|
|
mark_stack_top -> mse_start =
|
|
limit = current_p + SPLIT_RANGE_WORDS-1;
|
|
mark_stack_top -> mse_descr =
|
|
descr - WORDS_TO_BYTES(SPLIT_RANGE_WORDS-1);
|
|
/* Make sure that pointers overlapping the two ranges are */
|
|
/* considered. */
|
|
limit = (word *)((char *)limit + sizeof(word) - ALIGNMENT);
|
|
break;
|
|
case GC_DS_BITMAP:
|
|
mark_stack_top--;
|
|
descr &= ~GC_DS_TAGS;
|
|
credit -= WORDS_TO_BYTES(WORDSZ/2); /* guess */
|
|
while (descr != 0) {
|
|
if ((signed_word)descr < 0) {
|
|
current = *current_p;
|
|
FIXUP_POINTER(current);
|
|
if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
|
|
PREFETCH((ptr_t)current);
|
|
HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
|
|
mark_stack_limit, current_p, exit1);
|
|
}
|
|
}
|
|
descr <<= 1;
|
|
++ current_p;
|
|
}
|
|
continue;
|
|
case GC_DS_PROC:
|
|
mark_stack_top--;
|
|
credit -= GC_PROC_BYTES;
|
|
mark_stack_top =
|
|
(*PROC(descr))
|
|
(current_p, mark_stack_top,
|
|
mark_stack_limit, ENV(descr));
|
|
continue;
|
|
case GC_DS_PER_OBJECT:
|
|
if ((signed_word)descr >= 0) {
|
|
/* Descriptor is in the object. */
|
|
descr = *(word *)((ptr_t)current_p + descr - GC_DS_PER_OBJECT);
|
|
} else {
|
|
/* Descriptor is in type descriptor pointed to by first */
|
|
/* word in object. */
|
|
ptr_t type_descr = *(ptr_t *)current_p;
|
|
/* type_descr is either a valid pointer to the descriptor */
|
|
/* structure, or this object was on a free list. If it */
|
|
/* it was anything but the last object on the free list, */
|
|
/* we will misinterpret the next object on the free list as */
|
|
/* the type descriptor, and get a 0 GC descriptor, which */
|
|
/* is ideal. Unfortunately, we need to check for the last */
|
|
/* object case explicitly. */
|
|
if (0 == type_descr) {
|
|
/* Rarely executed. */
|
|
mark_stack_top--;
|
|
continue;
|
|
}
|
|
descr = *(word *)(type_descr
|
|
- (descr - (GC_DS_PER_OBJECT
|
|
- GC_INDIR_PER_OBJ_BIAS)));
|
|
}
|
|
if (0 == descr) {
|
|
/* Can happen either because we generated a 0 descriptor */
|
|
/* or we saw a pointer to a free object. */
|
|
mark_stack_top--;
|
|
continue;
|
|
}
|
|
goto retry;
|
|
}
|
|
} else /* Small object with length descriptor */ {
|
|
mark_stack_top--;
|
|
limit = (word *)(((ptr_t)current_p) + (word)descr);
|
|
}
|
|
/* The simple case in which we're scanning a range. */
|
|
GC_ASSERT(!((word)current_p & (ALIGNMENT-1)));
|
|
credit -= (ptr_t)limit - (ptr_t)current_p;
|
|
limit -= 1;
|
|
{
|
|
# define PREF_DIST 4
|
|
|
|
# ifndef SMALL_CONFIG
|
|
word deferred;
|
|
|
|
/* Try to prefetch the next pointer to be examined asap. */
|
|
/* Empirically, this also seems to help slightly without */
|
|
/* prefetches, at least on linux/X86. Presumably this loop */
|
|
/* ends up with less register pressure, and gcc thus ends up */
|
|
/* generating slightly better code. Overall gcc code quality */
|
|
/* for this loop is still not great. */
|
|
for(;;) {
|
|
PREFETCH((ptr_t)limit - PREF_DIST*CACHE_LINE_SIZE);
|
|
GC_ASSERT(limit >= current_p);
|
|
deferred = *limit;
|
|
FIXUP_POINTER(deferred);
|
|
limit = (word *)((char *)limit - ALIGNMENT);
|
|
if ((ptr_t)deferred >= least_ha && (ptr_t)deferred < greatest_ha) {
|
|
PREFETCH((ptr_t)deferred);
|
|
break;
|
|
}
|
|
if (current_p > limit) goto next_object;
|
|
/* Unroll once, so we don't do too many of the prefetches */
|
|
/* based on limit. */
|
|
deferred = *limit;
|
|
FIXUP_POINTER(deferred);
|
|
limit = (word *)((char *)limit - ALIGNMENT);
|
|
if ((ptr_t)deferred >= least_ha && (ptr_t)deferred < greatest_ha) {
|
|
PREFETCH((ptr_t)deferred);
|
|
break;
|
|
}
|
|
if (current_p > limit) goto next_object;
|
|
}
|
|
# endif
|
|
|
|
while (current_p <= limit) {
|
|
/* Empirically, unrolling this loop doesn't help a lot. */
|
|
/* Since HC_PUSH_CONTENTS expands to a lot of code, */
|
|
/* we don't. */
|
|
current = *current_p;
|
|
FIXUP_POINTER(current);
|
|
PREFETCH((ptr_t)current_p + PREF_DIST*CACHE_LINE_SIZE);
|
|
if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
|
|
/* Prefetch the contents of the object we just pushed. It's */
|
|
/* likely we will need them soon. */
|
|
PREFETCH((ptr_t)current);
|
|
HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
|
|
mark_stack_limit, current_p, exit2);
|
|
}
|
|
current_p = (word *)((char *)current_p + ALIGNMENT);
|
|
}
|
|
|
|
# ifndef SMALL_CONFIG
|
|
/* We still need to mark the entry we previously prefetched. */
|
|
/* We alrady know that it passes the preliminary pointer */
|
|
/* validity test. */
|
|
HC_PUSH_CONTENTS((ptr_t)deferred, mark_stack_top,
|
|
mark_stack_limit, current_p, exit4);
|
|
next_object:;
|
|
# endif
|
|
}
|
|
}
|
|
return mark_stack_top;
|
|
}
|
|
|
|
#ifdef PARALLEL_MARK
|
|
|
|
/* We assume we have an ANSI C Compiler. */
|
|
GC_bool GC_help_wanted = FALSE;
|
|
unsigned GC_helper_count = 0;
|
|
unsigned GC_active_count = 0;
|
|
mse * VOLATILE GC_first_nonempty;
|
|
word GC_mark_no = 0;
|
|
|
|
#define LOCAL_MARK_STACK_SIZE HBLKSIZE
|
|
/* Under normal circumstances, this is big enough to guarantee */
|
|
/* We don't overflow half of it in a single call to */
|
|
/* GC_mark_from. */
|
|
|
|
|
|
/* Steal mark stack entries starting at mse low into mark stack local */
|
|
/* until we either steal mse high, or we have max entries. */
|
|
/* Return a pointer to the top of the local mark stack. */
|
|
/* *next is replaced by a pointer to the next unscanned mark stack */
|
|
/* entry. */
|
|
mse * GC_steal_mark_stack(mse * low, mse * high, mse * local,
|
|
unsigned max, mse **next)
|
|
{
|
|
mse *p;
|
|
mse *top = local - 1;
|
|
unsigned i = 0;
|
|
|
|
/* Make sure that prior writes to the mark stack are visible. */
|
|
/* On some architectures, the fact that the reads are */
|
|
/* volatile should suffice. */
|
|
# if !defined(IA64) && !defined(HP_PA) && !defined(I386)
|
|
GC_memory_barrier();
|
|
# endif
|
|
GC_ASSERT(high >= low-1 && high - low + 1 <= GC_mark_stack_size);
|
|
for (p = low; p <= high && i <= max; ++p) {
|
|
word descr = *(volatile word *) &(p -> mse_descr);
|
|
/* In the IA64 memory model, the following volatile store is */
|
|
/* ordered after this read of descr. Thus a thread must read */
|
|
/* the original nonzero value. HP_PA appears to be similar, */
|
|
/* and if I'm reading the P4 spec correctly, X86 is probably */
|
|
/* also OK. In some other cases we need a barrier. */
|
|
# if !defined(IA64) && !defined(HP_PA) && !defined(I386)
|
|
GC_memory_barrier();
|
|
# endif
|
|
if (descr != 0) {
|
|
*(volatile word *) &(p -> mse_descr) = 0;
|
|
/* More than one thread may get this entry, but that's only */
|
|
/* a minor performance problem. */
|
|
++top;
|
|
top -> mse_descr = descr;
|
|
top -> mse_start = p -> mse_start;
|
|
GC_ASSERT( (top -> mse_descr & GC_DS_TAGS) != GC_DS_LENGTH ||
|
|
top -> mse_descr < (ptr_t)GC_greatest_plausible_heap_addr
|
|
- (ptr_t)GC_least_plausible_heap_addr);
|
|
/* If this is a big object, count it as */
|
|
/* size/256 + 1 objects. */
|
|
++i;
|
|
if ((descr & GC_DS_TAGS) == GC_DS_LENGTH) i += (descr >> 8);
|
|
}
|
|
}
|
|
*next = p;
|
|
return top;
|
|
}
|
|
|
|
/* Copy back a local mark stack. */
|
|
/* low and high are inclusive bounds. */
|
|
void GC_return_mark_stack(mse * low, mse * high)
|
|
{
|
|
mse * my_top;
|
|
mse * my_start;
|
|
size_t stack_size;
|
|
|
|
if (high < low) return;
|
|
stack_size = high - low + 1;
|
|
GC_acquire_mark_lock();
|
|
my_top = GC_mark_stack_top;
|
|
my_start = my_top + 1;
|
|
if (my_start - GC_mark_stack + stack_size > GC_mark_stack_size) {
|
|
# ifdef CONDPRINT
|
|
if (GC_print_stats) {
|
|
GC_printf0("No room to copy back mark stack.");
|
|
}
|
|
# endif
|
|
GC_mark_state = MS_INVALID;
|
|
GC_mark_stack_too_small = TRUE;
|
|
/* We drop the local mark stack. We'll fix things later. */
|
|
} else {
|
|
BCOPY(low, my_start, stack_size * sizeof(mse));
|
|
GC_ASSERT(GC_mark_stack_top = my_top);
|
|
# if !defined(IA64) && !defined(HP_PA)
|
|
GC_memory_barrier();
|
|
# endif
|
|
/* On IA64, the volatile write acts as a release barrier. */
|
|
GC_mark_stack_top = my_top + stack_size;
|
|
}
|
|
GC_release_mark_lock();
|
|
GC_notify_all_marker();
|
|
}
|
|
|
|
/* Mark from the local mark stack. */
|
|
/* On return, the local mark stack is empty. */
|
|
/* But this may be achieved by copying the */
|
|
/* local mark stack back into the global one. */
|
|
void GC_do_local_mark(mse *local_mark_stack, mse *local_top)
|
|
{
|
|
unsigned n;
|
|
# define N_LOCAL_ITERS 1
|
|
|
|
# ifdef GC_ASSERTIONS
|
|
/* Make sure we don't hold mark lock. */
|
|
GC_acquire_mark_lock();
|
|
GC_release_mark_lock();
|
|
# endif
|
|
for (;;) {
|
|
for (n = 0; n < N_LOCAL_ITERS; ++n) {
|
|
local_top = GC_mark_from(local_top, local_mark_stack,
|
|
local_mark_stack + LOCAL_MARK_STACK_SIZE);
|
|
if (local_top < local_mark_stack) return;
|
|
if (local_top - local_mark_stack >= LOCAL_MARK_STACK_SIZE/2) {
|
|
GC_return_mark_stack(local_mark_stack, local_top);
|
|
return;
|
|
}
|
|
}
|
|
if (GC_mark_stack_top < GC_first_nonempty &&
|
|
GC_active_count < GC_helper_count
|
|
&& local_top > local_mark_stack + 1) {
|
|
/* Try to share the load, since the main stack is empty, */
|
|
/* and helper threads are waiting for a refill. */
|
|
/* The entries near the bottom of the stack are likely */
|
|
/* to require more work. Thus we return those, eventhough */
|
|
/* it's harder. */
|
|
mse * p;
|
|
mse * new_bottom = local_mark_stack
|
|
+ (local_top - local_mark_stack)/2;
|
|
GC_ASSERT(new_bottom > local_mark_stack
|
|
&& new_bottom < local_top);
|
|
GC_return_mark_stack(local_mark_stack, new_bottom - 1);
|
|
memmove(local_mark_stack, new_bottom,
|
|
(local_top - new_bottom + 1) * sizeof(mse));
|
|
local_top -= (new_bottom - local_mark_stack);
|
|
}
|
|
}
|
|
}
|
|
|
|
#define ENTRIES_TO_GET 5
|
|
|
|
long GC_markers = 2; /* Normally changed by thread-library- */
|
|
/* -specific code. */
|
|
|
|
/* Mark using the local mark stack until the global mark stack is empty */
|
|
/* and there are no active workers. Update GC_first_nonempty to reflect */
|
|
/* progress. */
|
|
/* Caller does not hold mark lock. */
|
|
/* Caller has already incremented GC_helper_count. We decrement it, */
|
|
/* and maintain GC_active_count. */
|
|
void GC_mark_local(mse *local_mark_stack, int id)
|
|
{
|
|
mse * my_first_nonempty;
|
|
|
|
GC_acquire_mark_lock();
|
|
GC_active_count++;
|
|
my_first_nonempty = GC_first_nonempty;
|
|
GC_ASSERT(GC_first_nonempty >= GC_mark_stack &&
|
|
GC_first_nonempty <= GC_mark_stack_top + 1);
|
|
# ifdef PRINTSTATS
|
|
GC_printf1("Starting mark helper %lu\n", (unsigned long)id);
|
|
# endif
|
|
GC_release_mark_lock();
|
|
for (;;) {
|
|
size_t n_on_stack;
|
|
size_t n_to_get;
|
|
mse *next;
|
|
mse * my_top;
|
|
mse * local_top;
|
|
mse * global_first_nonempty = GC_first_nonempty;
|
|
|
|
GC_ASSERT(my_first_nonempty >= GC_mark_stack &&
|
|
my_first_nonempty <= GC_mark_stack_top + 1);
|
|
GC_ASSERT(global_first_nonempty >= GC_mark_stack &&
|
|
global_first_nonempty <= GC_mark_stack_top + 1);
|
|
if (my_first_nonempty < global_first_nonempty) {
|
|
my_first_nonempty = global_first_nonempty;
|
|
} else if (global_first_nonempty < my_first_nonempty) {
|
|
GC_compare_and_exchange((word *)(&GC_first_nonempty),
|
|
(word) global_first_nonempty,
|
|
(word) my_first_nonempty);
|
|
/* If this fails, we just go ahead, without updating */
|
|
/* GC_first_nonempty. */
|
|
}
|
|
/* Perhaps we should also update GC_first_nonempty, if it */
|
|
/* is less. But that would require using atomic updates. */
|
|
my_top = GC_mark_stack_top;
|
|
n_on_stack = my_top - my_first_nonempty + 1;
|
|
if (0 == n_on_stack) {
|
|
GC_acquire_mark_lock();
|
|
my_top = GC_mark_stack_top;
|
|
n_on_stack = my_top - my_first_nonempty + 1;
|
|
if (0 == n_on_stack) {
|
|
GC_active_count--;
|
|
GC_ASSERT(GC_active_count <= GC_helper_count);
|
|
/* Other markers may redeposit objects */
|
|
/* on the stack. */
|
|
if (0 == GC_active_count) GC_notify_all_marker();
|
|
while (GC_active_count > 0
|
|
&& GC_first_nonempty > GC_mark_stack_top) {
|
|
/* We will be notified if either GC_active_count */
|
|
/* reaches zero, or if more objects are pushed on */
|
|
/* the global mark stack. */
|
|
GC_wait_marker();
|
|
}
|
|
if (GC_active_count == 0 &&
|
|
GC_first_nonempty > GC_mark_stack_top) {
|
|
GC_bool need_to_notify = FALSE;
|
|
/* The above conditions can't be falsified while we */
|
|
/* hold the mark lock, since neither */
|
|
/* GC_active_count nor GC_mark_stack_top can */
|
|
/* change. GC_first_nonempty can only be */
|
|
/* incremented asynchronously. Thus we know that */
|
|
/* both conditions actually held simultaneously. */
|
|
GC_helper_count--;
|
|
if (0 == GC_helper_count) need_to_notify = TRUE;
|
|
# ifdef PRINTSTATS
|
|
GC_printf1(
|
|
"Finished mark helper %lu\n", (unsigned long)id);
|
|
# endif
|
|
GC_release_mark_lock();
|
|
if (need_to_notify) GC_notify_all_marker();
|
|
return;
|
|
}
|
|
/* else there's something on the stack again, or */
|
|
/* another helper may push something. */
|
|
GC_active_count++;
|
|
GC_ASSERT(GC_active_count > 0);
|
|
GC_release_mark_lock();
|
|
continue;
|
|
} else {
|
|
GC_release_mark_lock();
|
|
}
|
|
}
|
|
n_to_get = ENTRIES_TO_GET;
|
|
if (n_on_stack < 2 * ENTRIES_TO_GET) n_to_get = 1;
|
|
local_top = GC_steal_mark_stack(my_first_nonempty, my_top,
|
|
local_mark_stack, n_to_get,
|
|
&my_first_nonempty);
|
|
GC_ASSERT(my_first_nonempty >= GC_mark_stack &&
|
|
my_first_nonempty <= GC_mark_stack_top + 1);
|
|
GC_do_local_mark(local_mark_stack, local_top);
|
|
}
|
|
}
|
|
|
|
/* Perform Parallel mark. */
|
|
/* We hold the GC lock, not the mark lock. */
|
|
/* Currently runs until the mark stack is */
|
|
/* empty. */
|
|
void GC_do_parallel_mark()
|
|
{
|
|
mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
|
|
mse * local_top;
|
|
mse * my_top;
|
|
|
|
GC_acquire_mark_lock();
|
|
GC_ASSERT(I_HOLD_LOCK());
|
|
/* This could be a GC_ASSERT, but it seems safer to keep it on */
|
|
/* all the time, especially since it's cheap. */
|
|
if (GC_help_wanted || GC_active_count != 0 || GC_helper_count != 0)
|
|
ABORT("Tried to start parallel mark in bad state");
|
|
# ifdef PRINTSTATS
|
|
GC_printf1("Starting marking for mark phase number %lu\n",
|
|
(unsigned long)GC_mark_no);
|
|
# endif
|
|
GC_first_nonempty = GC_mark_stack;
|
|
GC_active_count = 0;
|
|
GC_helper_count = 1;
|
|
GC_help_wanted = TRUE;
|
|
GC_release_mark_lock();
|
|
GC_notify_all_marker();
|
|
/* Wake up potential helpers. */
|
|
GC_mark_local(local_mark_stack, 0);
|
|
GC_acquire_mark_lock();
|
|
GC_help_wanted = FALSE;
|
|
/* Done; clean up. */
|
|
while (GC_helper_count > 0) GC_wait_marker();
|
|
/* GC_helper_count cannot be incremented while GC_help_wanted == FALSE */
|
|
# ifdef PRINTSTATS
|
|
GC_printf1(
|
|
"Finished marking for mark phase number %lu\n",
|
|
(unsigned long)GC_mark_no);
|
|
# endif
|
|
GC_mark_no++;
|
|
GC_release_mark_lock();
|
|
GC_notify_all_marker();
|
|
}
|
|
|
|
|
|
/* Try to help out the marker, if it's running. */
|
|
/* We do not hold the GC lock, but the requestor does. */
|
|
void GC_help_marker(word my_mark_no)
|
|
{
|
|
mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
|
|
unsigned my_id;
|
|
mse * my_first_nonempty;
|
|
|
|
if (!GC_parallel) return;
|
|
GC_acquire_mark_lock();
|
|
while (GC_mark_no < my_mark_no
|
|
|| !GC_help_wanted && GC_mark_no == my_mark_no) {
|
|
GC_wait_marker();
|
|
}
|
|
my_id = GC_helper_count;
|
|
if (GC_mark_no != my_mark_no || my_id >= GC_markers) {
|
|
/* Second test is useful only if original threads can also */
|
|
/* act as helpers. Under Linux they can't. */
|
|
GC_release_mark_lock();
|
|
return;
|
|
}
|
|
GC_helper_count = my_id + 1;
|
|
GC_release_mark_lock();
|
|
GC_mark_local(local_mark_stack, my_id);
|
|
/* GC_mark_local decrements GC_helper_count. */
|
|
}
|
|
|
|
#endif /* PARALLEL_MARK */
|
|
|
|
/* Allocate or reallocate space for mark stack of size s words */
|
|
/* May silently fail. */
|
|
static void alloc_mark_stack(n)
|
|
word n;
|
|
{
|
|
mse * new_stack = (mse *)GC_scratch_alloc(n * sizeof(struct GC_ms_entry));
|
|
|
|
GC_mark_stack_too_small = FALSE;
|
|
if (GC_mark_stack_size != 0) {
|
|
if (new_stack != 0) {
|
|
word displ = (word)GC_mark_stack & (GC_page_size - 1);
|
|
signed_word size = GC_mark_stack_size * sizeof(struct GC_ms_entry);
|
|
|
|
/* Recycle old space */
|
|
if (0 != displ) displ = GC_page_size - displ;
|
|
size = (size - displ) & ~(GC_page_size - 1);
|
|
if (size > 0) {
|
|
GC_add_to_heap((struct hblk *)
|
|
((word)GC_mark_stack + displ), (word)size);
|
|
}
|
|
GC_mark_stack = new_stack;
|
|
GC_mark_stack_size = n;
|
|
GC_mark_stack_limit = new_stack + n;
|
|
# ifdef CONDPRINT
|
|
if (GC_print_stats) {
|
|
GC_printf1("Grew mark stack to %lu frames\n",
|
|
(unsigned long) GC_mark_stack_size);
|
|
}
|
|
# endif
|
|
} else {
|
|
# ifdef CONDPRINT
|
|
if (GC_print_stats) {
|
|
GC_printf1("Failed to grow mark stack to %lu frames\n",
|
|
(unsigned long) n);
|
|
}
|
|
# endif
|
|
}
|
|
} else {
|
|
if (new_stack == 0) {
|
|
GC_err_printf0("No space for mark stack\n");
|
|
EXIT();
|
|
}
|
|
GC_mark_stack = new_stack;
|
|
GC_mark_stack_size = n;
|
|
GC_mark_stack_limit = new_stack + n;
|
|
}
|
|
GC_mark_stack_top = GC_mark_stack-1;
|
|
}
|
|
|
|
void GC_mark_init()
|
|
{
|
|
alloc_mark_stack(INITIAL_MARK_STACK_SIZE);
|
|
}
|
|
|
|
/*
|
|
* Push all locations between b and t onto the mark stack.
|
|
* b is the first location to be checked. t is one past the last
|
|
* location to be checked.
|
|
* Should only be used if there is no possibility of mark stack
|
|
* overflow.
|
|
*/
|
|
void GC_push_all(bottom, top)
|
|
ptr_t bottom;
|
|
ptr_t top;
|
|
{
|
|
register word length;
|
|
|
|
bottom = (ptr_t)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
|
|
top = (ptr_t)(((word) top) & ~(ALIGNMENT-1));
|
|
if (top == 0 || bottom == top) return;
|
|
GC_mark_stack_top++;
|
|
if (GC_mark_stack_top >= GC_mark_stack_limit) {
|
|
ABORT("unexpected mark stack overflow");
|
|
}
|
|
length = top - bottom;
|
|
# if GC_DS_TAGS > ALIGNMENT - 1
|
|
length += GC_DS_TAGS;
|
|
length &= ~GC_DS_TAGS;
|
|
# endif
|
|
GC_mark_stack_top -> mse_start = (word *)bottom;
|
|
GC_mark_stack_top -> mse_descr = length;
|
|
}
|
|
|
|
/*
|
|
* Analogous to the above, but push only those pages h with dirty_fn(h) != 0.
|
|
* We use push_fn to actually push the block.
|
|
* Used both to selectively push dirty pages, or to push a block
|
|
* in piecemeal fashion, to allow for more marking concurrency.
|
|
* Will not overflow mark stack if push_fn pushes a small fixed number
|
|
* of entries. (This is invoked only if push_fn pushes a single entry,
|
|
* or if it marks each object before pushing it, thus ensuring progress
|
|
* in the event of a stack overflow.)
|
|
*/
|
|
void GC_push_selected(bottom, top, dirty_fn, push_fn)
|
|
ptr_t bottom;
|
|
ptr_t top;
|
|
int (*dirty_fn) GC_PROTO((struct hblk * h));
|
|
void (*push_fn) GC_PROTO((ptr_t bottom, ptr_t top));
|
|
{
|
|
register struct hblk * h;
|
|
|
|
bottom = (ptr_t)(((long) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
|
|
top = (ptr_t)(((long) top) & ~(ALIGNMENT-1));
|
|
|
|
if (top == 0 || bottom == top) return;
|
|
h = HBLKPTR(bottom + HBLKSIZE);
|
|
if (top <= (ptr_t) h) {
|
|
if ((*dirty_fn)(h-1)) {
|
|
(*push_fn)(bottom, top);
|
|
}
|
|
return;
|
|
}
|
|
if ((*dirty_fn)(h-1)) {
|
|
(*push_fn)(bottom, (ptr_t)h);
|
|
}
|
|
while ((ptr_t)(h+1) <= top) {
|
|
if ((*dirty_fn)(h)) {
|
|
if ((word)(GC_mark_stack_top - GC_mark_stack)
|
|
> 3 * GC_mark_stack_size / 4) {
|
|
/* Danger of mark stack overflow */
|
|
(*push_fn)((ptr_t)h, top);
|
|
return;
|
|
} else {
|
|
(*push_fn)((ptr_t)h, (ptr_t)(h+1));
|
|
}
|
|
}
|
|
h++;
|
|
}
|
|
if ((ptr_t)h != top) {
|
|
if ((*dirty_fn)(h)) {
|
|
(*push_fn)((ptr_t)h, top);
|
|
}
|
|
}
|
|
if (GC_mark_stack_top >= GC_mark_stack_limit) {
|
|
ABORT("unexpected mark stack overflow");
|
|
}
|
|
}
|
|
|
|
# ifndef SMALL_CONFIG
|
|
|
|
#ifdef PARALLEL_MARK
|
|
/* Break up root sections into page size chunks to better spread */
|
|
/* out work. */
|
|
GC_bool GC_true_func(struct hblk *h) { return TRUE; }
|
|
# define GC_PUSH_ALL(b,t) GC_push_selected(b,t,GC_true_func,GC_push_all);
|
|
#else
|
|
# define GC_PUSH_ALL(b,t) GC_push_all(b,t);
|
|
#endif
|
|
|
|
|
|
void GC_push_conditional(bottom, top, all)
|
|
ptr_t bottom;
|
|
ptr_t top;
|
|
int all;
|
|
{
|
|
if (all) {
|
|
if (GC_dirty_maintained) {
|
|
# ifdef PROC_VDB
|
|
/* Pages that were never dirtied cannot contain pointers */
|
|
GC_push_selected(bottom, top, GC_page_was_ever_dirty, GC_push_all);
|
|
# else
|
|
GC_push_all(bottom, top);
|
|
# endif
|
|
} else {
|
|
GC_push_all(bottom, top);
|
|
}
|
|
} else {
|
|
GC_push_selected(bottom, top, GC_page_was_dirty, GC_push_all);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
# if defined(MSWIN32) || defined(MSWINCE)
|
|
void __cdecl GC_push_one(p)
|
|
# else
|
|
void GC_push_one(p)
|
|
# endif
|
|
word p;
|
|
{
|
|
GC_PUSH_ONE_STACK(p, MARKED_FROM_REGISTER);
|
|
}
|
|
|
|
struct GC_ms_entry *GC_mark_and_push(obj, mark_stack_ptr, mark_stack_limit, src)
|
|
GC_PTR obj;
|
|
struct GC_ms_entry * mark_stack_ptr;
|
|
struct GC_ms_entry * mark_stack_limit;
|
|
GC_PTR *src;
|
|
{
|
|
PREFETCH(obj);
|
|
PUSH_CONTENTS(obj, mark_stack_ptr /* modified */, mark_stack_limit, src,
|
|
was_marked /* internally generated exit label */);
|
|
return mark_stack_ptr;
|
|
}
|
|
|
|
# ifdef __STDC__
|
|
# define BASE(p) (word)GC_base((void *)(p))
|
|
# else
|
|
# define BASE(p) (word)GC_base((char *)(p))
|
|
# endif
|
|
|
|
/* Mark and push (i.e. gray) a single object p onto the main */
|
|
/* mark stack. Consider p to be valid if it is an interior */
|
|
/* pointer. */
|
|
/* The object p has passed a preliminary pointer validity */
|
|
/* test, but we do not definitely know whether it is valid. */
|
|
/* Mark bits are NOT atomically updated. Thus this must be the */
|
|
/* only thread setting them. */
|
|
# if defined(PRINT_BLACK_LIST) || defined(KEEP_BACK_PTRS)
|
|
void GC_mark_and_push_stack(p, source)
|
|
ptr_t source;
|
|
# else
|
|
void GC_mark_and_push_stack(p)
|
|
# define source 0
|
|
# endif
|
|
register word p;
|
|
{
|
|
register word r;
|
|
register hdr * hhdr;
|
|
register int displ;
|
|
|
|
GET_HDR(p, hhdr);
|
|
if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
|
|
if (hhdr != 0) {
|
|
r = BASE(p);
|
|
hhdr = HDR(r);
|
|
displ = BYTES_TO_WORDS(HBLKDISPL(r));
|
|
}
|
|
} else {
|
|
register map_entry_type map_entry;
|
|
|
|
displ = HBLKDISPL(p);
|
|
map_entry = MAP_ENTRY((hhdr -> hb_map), displ);
|
|
if (map_entry >= MAX_OFFSET) {
|
|
if (map_entry == OFFSET_TOO_BIG || !GC_all_interior_pointers) {
|
|
r = BASE(p);
|
|
displ = BYTES_TO_WORDS(HBLKDISPL(r));
|
|
if (r == 0) hhdr = 0;
|
|
} else {
|
|
/* Offset invalid, but map reflects interior pointers */
|
|
hhdr = 0;
|
|
}
|
|
} else {
|
|
displ = BYTES_TO_WORDS(displ);
|
|
displ -= map_entry;
|
|
r = (word)((word *)(HBLKPTR(p)) + displ);
|
|
}
|
|
}
|
|
/* If hhdr != 0 then r == GC_base(p), only we did it faster. */
|
|
/* displ is the word index within the block. */
|
|
if (hhdr == 0) {
|
|
# ifdef PRINT_BLACK_LIST
|
|
GC_add_to_black_list_stack(p, source);
|
|
# else
|
|
GC_add_to_black_list_stack(p);
|
|
# endif
|
|
# undef source /* In case we had to define it. */
|
|
} else {
|
|
if (!mark_bit_from_hdr(hhdr, displ)) {
|
|
set_mark_bit_from_hdr(hhdr, displ);
|
|
GC_STORE_BACK_PTR(source, (ptr_t)r);
|
|
PUSH_OBJ((word *)r, hhdr, GC_mark_stack_top,
|
|
GC_mark_stack_limit);
|
|
}
|
|
}
|
|
}
|
|
|
|
# ifdef TRACE_BUF
|
|
|
|
# define TRACE_ENTRIES 1000
|
|
|
|
struct trace_entry {
|
|
char * kind;
|
|
word gc_no;
|
|
word words_allocd;
|
|
word arg1;
|
|
word arg2;
|
|
} GC_trace_buf[TRACE_ENTRIES];
|
|
|
|
int GC_trace_buf_ptr = 0;
|
|
|
|
void GC_add_trace_entry(char *kind, word arg1, word arg2)
|
|
{
|
|
GC_trace_buf[GC_trace_buf_ptr].kind = kind;
|
|
GC_trace_buf[GC_trace_buf_ptr].gc_no = GC_gc_no;
|
|
GC_trace_buf[GC_trace_buf_ptr].words_allocd = GC_words_allocd;
|
|
GC_trace_buf[GC_trace_buf_ptr].arg1 = arg1 ^ 0x80000000;
|
|
GC_trace_buf[GC_trace_buf_ptr].arg2 = arg2 ^ 0x80000000;
|
|
GC_trace_buf_ptr++;
|
|
if (GC_trace_buf_ptr >= TRACE_ENTRIES) GC_trace_buf_ptr = 0;
|
|
}
|
|
|
|
void GC_print_trace(word gc_no, GC_bool lock)
|
|
{
|
|
int i;
|
|
struct trace_entry *p;
|
|
|
|
if (lock) LOCK();
|
|
for (i = GC_trace_buf_ptr-1; i != GC_trace_buf_ptr; i--) {
|
|
if (i < 0) i = TRACE_ENTRIES-1;
|
|
p = GC_trace_buf + i;
|
|
if (p -> gc_no < gc_no || p -> kind == 0) return;
|
|
printf("Trace:%s (gc:%d,words:%d) 0x%X, 0x%X\n",
|
|
p -> kind, p -> gc_no, p -> words_allocd,
|
|
(p -> arg1) ^ 0x80000000, (p -> arg2) ^ 0x80000000);
|
|
}
|
|
printf("Trace incomplete\n");
|
|
if (lock) UNLOCK();
|
|
}
|
|
|
|
# endif /* TRACE_BUF */
|
|
|
|
/*
|
|
* A version of GC_push_all that treats all interior pointers as valid
|
|
* and scans the entire region immediately, in case the contents
|
|
* change.
|
|
*/
|
|
void GC_push_all_eager(bottom, top)
|
|
ptr_t bottom;
|
|
ptr_t top;
|
|
{
|
|
word * b = (word *)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
|
|
word * t = (word *)(((word) top) & ~(ALIGNMENT-1));
|
|
register word *p;
|
|
register word q;
|
|
register word *lim;
|
|
register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
|
|
register ptr_t least_ha = GC_least_plausible_heap_addr;
|
|
# define GC_greatest_plausible_heap_addr greatest_ha
|
|
# define GC_least_plausible_heap_addr least_ha
|
|
|
|
if (top == 0) return;
|
|
/* check all pointers in range and push if they appear */
|
|
/* to be valid. */
|
|
lim = t - 1 /* longword */;
|
|
for (p = b; p <= lim; p = (word *)(((char *)p) + ALIGNMENT)) {
|
|
q = *p;
|
|
GC_PUSH_ONE_STACK(q, p);
|
|
}
|
|
# undef GC_greatest_plausible_heap_addr
|
|
# undef GC_least_plausible_heap_addr
|
|
}
|
|
|
|
#ifndef THREADS
|
|
/*
|
|
* A version of GC_push_all that treats all interior pointers as valid
|
|
* and scans part of the area immediately, to make sure that saved
|
|
* register values are not lost.
|
|
* Cold_gc_frame delimits the stack section that must be scanned
|
|
* eagerly. A zero value indicates that no eager scanning is needed.
|
|
*/
|
|
void GC_push_all_stack_partially_eager(bottom, top, cold_gc_frame)
|
|
ptr_t bottom;
|
|
ptr_t top;
|
|
ptr_t cold_gc_frame;
|
|
{
|
|
if (!NEED_FIXUP_POINTER && GC_all_interior_pointers) {
|
|
# define EAGER_BYTES 1024
|
|
/* Push the hot end of the stack eagerly, so that register values */
|
|
/* saved inside GC frames are marked before they disappear. */
|
|
/* The rest of the marking can be deferred until later. */
|
|
if (0 == cold_gc_frame) {
|
|
GC_push_all_stack(bottom, top);
|
|
return;
|
|
}
|
|
GC_ASSERT(bottom <= cold_gc_frame && cold_gc_frame <= top);
|
|
# ifdef STACK_GROWS_DOWN
|
|
GC_push_all(cold_gc_frame - sizeof(ptr_t), top);
|
|
GC_push_all_eager(bottom, cold_gc_frame);
|
|
# else /* STACK_GROWS_UP */
|
|
GC_push_all(bottom, cold_gc_frame + sizeof(ptr_t));
|
|
GC_push_all_eager(cold_gc_frame, top);
|
|
# endif /* STACK_GROWS_UP */
|
|
} else {
|
|
GC_push_all_eager(bottom, top);
|
|
}
|
|
# ifdef TRACE_BUF
|
|
GC_add_trace_entry("GC_push_all_stack", bottom, top);
|
|
# endif
|
|
}
|
|
#endif /* !THREADS */
|
|
|
|
void GC_push_all_stack(bottom, top)
|
|
ptr_t bottom;
|
|
ptr_t top;
|
|
{
|
|
if (!NEED_FIXUP_POINTER && GC_all_interior_pointers) {
|
|
GC_push_all(bottom, top);
|
|
} else {
|
|
GC_push_all_eager(bottom, top);
|
|
}
|
|
}
|
|
|
|
#if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
|
|
/* Push all objects reachable from marked objects in the given block */
|
|
/* of size 1 objects. */
|
|
void GC_push_marked1(h, hhdr)
|
|
struct hblk *h;
|
|
register hdr * hhdr;
|
|
{
|
|
word * mark_word_addr = &(hhdr->hb_marks[0]);
|
|
register word *p;
|
|
word *plim;
|
|
register int i;
|
|
register word q;
|
|
register word mark_word;
|
|
register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
|
|
register ptr_t least_ha = GC_least_plausible_heap_addr;
|
|
register mse * mark_stack_top = GC_mark_stack_top;
|
|
register mse * mark_stack_limit = GC_mark_stack_limit;
|
|
# define GC_mark_stack_top mark_stack_top
|
|
# define GC_mark_stack_limit mark_stack_limit
|
|
# define GC_greatest_plausible_heap_addr greatest_ha
|
|
# define GC_least_plausible_heap_addr least_ha
|
|
|
|
p = (word *)(h->hb_body);
|
|
plim = (word *)(((word)h) + HBLKSIZE);
|
|
|
|
/* go through all words in block */
|
|
while( p < plim ) {
|
|
mark_word = *mark_word_addr++;
|
|
i = 0;
|
|
while(mark_word != 0) {
|
|
if (mark_word & 1) {
|
|
q = p[i];
|
|
GC_PUSH_ONE_HEAP(q, p + i);
|
|
}
|
|
i++;
|
|
mark_word >>= 1;
|
|
}
|
|
p += WORDSZ;
|
|
}
|
|
# undef GC_greatest_plausible_heap_addr
|
|
# undef GC_least_plausible_heap_addr
|
|
# undef GC_mark_stack_top
|
|
# undef GC_mark_stack_limit
|
|
GC_mark_stack_top = mark_stack_top;
|
|
}
|
|
|
|
|
|
#ifndef UNALIGNED
|
|
|
|
/* Push all objects reachable from marked objects in the given block */
|
|
/* of size 2 objects. */
|
|
void GC_push_marked2(h, hhdr)
|
|
struct hblk *h;
|
|
register hdr * hhdr;
|
|
{
|
|
word * mark_word_addr = &(hhdr->hb_marks[0]);
|
|
register word *p;
|
|
word *plim;
|
|
register int i;
|
|
register word q;
|
|
register word mark_word;
|
|
register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
|
|
register ptr_t least_ha = GC_least_plausible_heap_addr;
|
|
register mse * mark_stack_top = GC_mark_stack_top;
|
|
register mse * mark_stack_limit = GC_mark_stack_limit;
|
|
# define GC_mark_stack_top mark_stack_top
|
|
# define GC_mark_stack_limit mark_stack_limit
|
|
# define GC_greatest_plausible_heap_addr greatest_ha
|
|
# define GC_least_plausible_heap_addr least_ha
|
|
|
|
p = (word *)(h->hb_body);
|
|
plim = (word *)(((word)h) + HBLKSIZE);
|
|
|
|
/* go through all words in block */
|
|
while( p < plim ) {
|
|
mark_word = *mark_word_addr++;
|
|
i = 0;
|
|
while(mark_word != 0) {
|
|
if (mark_word & 1) {
|
|
q = p[i];
|
|
GC_PUSH_ONE_HEAP(q, p + i);
|
|
q = p[i+1];
|
|
GC_PUSH_ONE_HEAP(q, p + i);
|
|
}
|
|
i += 2;
|
|
mark_word >>= 2;
|
|
}
|
|
p += WORDSZ;
|
|
}
|
|
# undef GC_greatest_plausible_heap_addr
|
|
# undef GC_least_plausible_heap_addr
|
|
# undef GC_mark_stack_top
|
|
# undef GC_mark_stack_limit
|
|
GC_mark_stack_top = mark_stack_top;
|
|
}
|
|
|
|
/* Push all objects reachable from marked objects in the given block */
|
|
/* of size 4 objects. */
|
|
/* There is a risk of mark stack overflow here. But we handle that. */
|
|
/* And only unmarked objects get pushed, so it's not very likely. */
|
|
void GC_push_marked4(h, hhdr)
|
|
struct hblk *h;
|
|
register hdr * hhdr;
|
|
{
|
|
word * mark_word_addr = &(hhdr->hb_marks[0]);
|
|
register word *p;
|
|
word *plim;
|
|
register int i;
|
|
register word q;
|
|
register word mark_word;
|
|
register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
|
|
register ptr_t least_ha = GC_least_plausible_heap_addr;
|
|
register mse * mark_stack_top = GC_mark_stack_top;
|
|
register mse * mark_stack_limit = GC_mark_stack_limit;
|
|
# define GC_mark_stack_top mark_stack_top
|
|
# define GC_mark_stack_limit mark_stack_limit
|
|
# define GC_greatest_plausible_heap_addr greatest_ha
|
|
# define GC_least_plausible_heap_addr least_ha
|
|
|
|
p = (word *)(h->hb_body);
|
|
plim = (word *)(((word)h) + HBLKSIZE);
|
|
|
|
/* go through all words in block */
|
|
while( p < plim ) {
|
|
mark_word = *mark_word_addr++;
|
|
i = 0;
|
|
while(mark_word != 0) {
|
|
if (mark_word & 1) {
|
|
q = p[i];
|
|
GC_PUSH_ONE_HEAP(q, p + i);
|
|
q = p[i+1];
|
|
GC_PUSH_ONE_HEAP(q, p + i + 1);
|
|
q = p[i+2];
|
|
GC_PUSH_ONE_HEAP(q, p + i + 2);
|
|
q = p[i+3];
|
|
GC_PUSH_ONE_HEAP(q, p + i + 3);
|
|
}
|
|
i += 4;
|
|
mark_word >>= 4;
|
|
}
|
|
p += WORDSZ;
|
|
}
|
|
# undef GC_greatest_plausible_heap_addr
|
|
# undef GC_least_plausible_heap_addr
|
|
# undef GC_mark_stack_top
|
|
# undef GC_mark_stack_limit
|
|
GC_mark_stack_top = mark_stack_top;
|
|
}
|
|
|
|
#endif /* UNALIGNED */
|
|
|
|
#endif /* SMALL_CONFIG */
|
|
|
|
/* Push all objects reachable from marked objects in the given block */
|
|
void GC_push_marked(h, hhdr)
|
|
struct hblk *h;
|
|
register hdr * hhdr;
|
|
{
|
|
register int sz = hhdr -> hb_sz;
|
|
register int descr = hhdr -> hb_descr;
|
|
register word * p;
|
|
register int word_no;
|
|
register word * lim;
|
|
register mse * GC_mark_stack_top_reg;
|
|
register mse * mark_stack_limit = GC_mark_stack_limit;
|
|
|
|
/* Some quick shortcuts: */
|
|
if ((0 | GC_DS_LENGTH) == descr) return;
|
|
if (GC_block_empty(hhdr)/* nothing marked */) return;
|
|
GC_n_rescuing_pages++;
|
|
GC_objects_are_marked = TRUE;
|
|
if (sz > MAXOBJSZ) {
|
|
lim = (word *)h;
|
|
} else {
|
|
lim = (word *)(h + 1) - sz;
|
|
}
|
|
|
|
switch(sz) {
|
|
# if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
|
|
case 1:
|
|
GC_push_marked1(h, hhdr);
|
|
break;
|
|
# endif
|
|
# if !defined(SMALL_CONFIG) && !defined(UNALIGNED) && \
|
|
!defined(USE_MARK_BYTES)
|
|
case 2:
|
|
GC_push_marked2(h, hhdr);
|
|
break;
|
|
case 4:
|
|
GC_push_marked4(h, hhdr);
|
|
break;
|
|
# endif
|
|
default:
|
|
GC_mark_stack_top_reg = GC_mark_stack_top;
|
|
for (p = (word *)h, word_no = 0; p <= lim; p += sz, word_no += sz) {
|
|
if (mark_bit_from_hdr(hhdr, word_no)) {
|
|
/* Mark from fields inside the object */
|
|
PUSH_OBJ((word *)p, hhdr, GC_mark_stack_top_reg, mark_stack_limit);
|
|
# ifdef GATHERSTATS
|
|
/* Subtract this object from total, since it was */
|
|
/* added in twice. */
|
|
GC_composite_in_use -= sz;
|
|
# endif
|
|
}
|
|
}
|
|
GC_mark_stack_top = GC_mark_stack_top_reg;
|
|
}
|
|
}
|
|
|
|
#ifndef SMALL_CONFIG
|
|
/* Test whether any page in the given block is dirty */
|
|
GC_bool GC_block_was_dirty(h, hhdr)
|
|
struct hblk *h;
|
|
register hdr * hhdr;
|
|
{
|
|
register int sz = hhdr -> hb_sz;
|
|
|
|
if (sz <= MAXOBJSZ) {
|
|
return(GC_page_was_dirty(h));
|
|
} else {
|
|
register ptr_t p = (ptr_t)h;
|
|
sz = WORDS_TO_BYTES(sz);
|
|
while (p < (ptr_t)h + sz) {
|
|
if (GC_page_was_dirty((struct hblk *)p)) return(TRUE);
|
|
p += HBLKSIZE;
|
|
}
|
|
return(FALSE);
|
|
}
|
|
}
|
|
#endif /* SMALL_CONFIG */
|
|
|
|
/* Similar to GC_push_next_marked, but return address of next block */
|
|
struct hblk * GC_push_next_marked(h)
|
|
struct hblk *h;
|
|
{
|
|
register hdr * hhdr;
|
|
|
|
h = GC_next_used_block(h);
|
|
if (h == 0) return(0);
|
|
hhdr = HDR(h);
|
|
GC_push_marked(h, hhdr);
|
|
return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
|
|
}
|
|
|
|
#ifndef SMALL_CONFIG
|
|
/* Identical to above, but mark only from dirty pages */
|
|
struct hblk * GC_push_next_marked_dirty(h)
|
|
struct hblk *h;
|
|
{
|
|
register hdr * hhdr;
|
|
|
|
if (!GC_dirty_maintained) { ABORT("dirty bits not set up"); }
|
|
for (;;) {
|
|
h = GC_next_used_block(h);
|
|
if (h == 0) return(0);
|
|
hhdr = HDR(h);
|
|
# ifdef STUBBORN_ALLOC
|
|
if (hhdr -> hb_obj_kind == STUBBORN) {
|
|
if (GC_page_was_changed(h) && GC_block_was_dirty(h, hhdr)) {
|
|
break;
|
|
}
|
|
} else {
|
|
if (GC_block_was_dirty(h, hhdr)) break;
|
|
}
|
|
# else
|
|
if (GC_block_was_dirty(h, hhdr)) break;
|
|
# endif
|
|
h += OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
|
|
}
|
|
GC_push_marked(h, hhdr);
|
|
return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
|
|
}
|
|
#endif
|
|
|
|
/* Similar to above, but for uncollectable pages. Needed since we */
|
|
/* do not clear marks for such pages, even for full collections. */
|
|
struct hblk * GC_push_next_marked_uncollectable(h)
|
|
struct hblk *h;
|
|
{
|
|
register hdr * hhdr = HDR(h);
|
|
|
|
for (;;) {
|
|
h = GC_next_used_block(h);
|
|
if (h == 0) return(0);
|
|
hhdr = HDR(h);
|
|
if (hhdr -> hb_obj_kind == UNCOLLECTABLE) break;
|
|
h += OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
|
|
}
|
|
GC_push_marked(h, hhdr);
|
|
return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
|
|
}
|
|
|
|
|