2047 lines
76 KiB
C
2047 lines
76 KiB
C
/*
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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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#if defined(__MINGW32__) && !defined(__MINGW_EXCPT_DEFINE_PSDK) \
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&& defined(__i386__) /* cannot use macros from gcconfig.h */
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/* Otherwise EXCEPTION_REGISTRATION type declaration from winnt.h */
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/* might be used. That declaration has "handler" callback with NTAPI */
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/* attribute. The proper type (with "handler" field compatible with */
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/* GC mark_ex_handler) is declared in excpt.h. The given macro is */
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/* defined before any system header include. */
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# define __MINGW_EXCPT_DEFINE_PSDK 1
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#endif
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#include "private/gc_pmark.h"
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#include <stdio.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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/* Make arguments appear live to compiler. Put here to minimize the */
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/* risk of inlining. Used to minimize junk left in registers. */
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GC_ATTR_NOINLINE
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void GC_noop6(word arg1 GC_ATTR_UNUSED, word arg2 GC_ATTR_UNUSED,
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word arg3 GC_ATTR_UNUSED, word arg4 GC_ATTR_UNUSED,
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word arg5 GC_ATTR_UNUSED, word arg6 GC_ATTR_UNUSED)
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{
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/* Avoid GC_noop6 calls to be optimized away. */
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# ifdef AO_CLEAR
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AO_compiler_barrier(); /* to serve as a special side-effect */
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# else
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GC_noop1(0);
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# endif
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}
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volatile word GC_noop_sink;
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/* Single argument version, robust against whole program analysis. */
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GC_ATTR_NO_SANITIZE_THREAD
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GC_API void GC_CALL GC_noop1(word x)
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{
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GC_noop_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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GC_INNER unsigned 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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GC_INNER 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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/*, */ OK_DISCLAIM_INITZ },
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/* NORMAL */ { &GC_objfreelist[0], 0,
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/* 0 | */ GC_DS_LENGTH,
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/* adjusted in GC_init for EXTRA_BYTES */
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TRUE /* add length to descr */, TRUE
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/*, */ OK_DISCLAIM_INITZ },
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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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/*, */ OK_DISCLAIM_INITZ },
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# ifdef GC_ATOMIC_UNCOLLECTABLE
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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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/*, */ OK_DISCLAIM_INITZ },
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# endif
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};
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GC_INNER unsigned GC_n_kinds = GC_N_KINDS_INITIAL_VALUE;
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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 wants to push all marked dirty */
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/* objects before marking anything new. Currently we */
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/* let it grow dynamically. */
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# endif
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#if !defined(GC_DISABLE_INCREMENTAL)
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STATIC word GC_n_rescuing_pages = 0;
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/* Number of dirty pages we marked from */
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/* excludes ptrfree pages, etc. */
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/* Used for logging only. */
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#endif
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GC_INNER size_t GC_mark_stack_size = 0;
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#ifdef PARALLEL_MARK
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STATIC volatile AO_t GC_first_nonempty = 0;
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/* Lowest entry on mark stack */
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/* that may be nonempty. */
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/* Updated only by initiating */
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/* thread. */
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#endif
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GC_INNER mark_state_t GC_mark_state = MS_NONE;
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GC_INNER GC_bool GC_mark_stack_too_small = FALSE;
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static struct hblk * scan_ptr;
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STATIC GC_bool GC_objects_are_marked = FALSE;
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/* Are there collectible marked 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_INNER GC_bool GC_collection_in_progress(void)
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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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GC_INNER void GC_clear_hdr_marks(hdr *hhdr)
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{
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size_t last_bit;
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# ifdef AO_HAVE_load
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/* Atomic access is used to avoid racing with GC_realloc. */
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last_bit = FINAL_MARK_BIT((size_t)AO_load((volatile AO_t *)&hhdr->hb_sz));
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# else
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/* No race as GC_realloc holds the lock while updating hb_sz. */
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last_bit = FINAL_MARK_BIT((size_t)hhdr->hb_sz);
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# endif
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BZERO(hhdr -> hb_marks, sizeof(hhdr->hb_marks));
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set_mark_bit_from_hdr(hhdr, last_bit);
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hhdr -> hb_n_marks = 0;
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}
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/* Set all mark bits in the header. Used for uncollectible blocks. */
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GC_INNER void GC_set_hdr_marks(hdr *hhdr)
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{
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unsigned i;
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size_t sz = (size_t)hhdr->hb_sz;
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unsigned n_marks = (unsigned)FINAL_MARK_BIT(sz);
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# ifdef USE_MARK_BYTES
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for (i = 0; i <= n_marks; i += (unsigned)MARK_BIT_OFFSET(sz)) {
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hhdr -> hb_marks[i] = 1;
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}
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# else
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for (i = 0; i < divWORDSZ(n_marks + WORDSZ); ++i) {
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hhdr -> hb_marks[i] = ONES;
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}
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# endif
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# ifdef MARK_BIT_PER_OBJ
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hhdr -> hb_n_marks = n_marks;
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# else
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hhdr -> hb_n_marks = HBLK_OBJS(sz);
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# endif
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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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static void clear_marks_for_block(struct hblk *h, word dummy GC_ATTR_UNUSED)
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{
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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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GC_API void GC_CALL GC_set_mark_bit(const void *p)
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{
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struct hblk *h = HBLKPTR(p);
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hdr * hhdr = HDR(h);
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word bit_no = MARK_BIT_NO((ptr_t)p - (ptr_t)h, hhdr -> hb_sz);
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if (!mark_bit_from_hdr(hhdr, bit_no)) {
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set_mark_bit_from_hdr(hhdr, bit_no);
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++hhdr -> hb_n_marks;
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}
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}
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GC_API void GC_CALL GC_clear_mark_bit(const void *p)
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{
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struct hblk *h = HBLKPTR(p);
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hdr * hhdr = HDR(h);
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word bit_no = MARK_BIT_NO((ptr_t)p - (ptr_t)h, hhdr -> hb_sz);
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if (mark_bit_from_hdr(hhdr, bit_no)) {
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size_t n_marks = hhdr -> hb_n_marks;
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GC_ASSERT(n_marks != 0);
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clear_mark_bit_from_hdr(hhdr, bit_no);
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n_marks--;
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# ifdef PARALLEL_MARK
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if (n_marks != 0 || !GC_parallel)
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hhdr -> hb_n_marks = n_marks;
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/* Don't decrement to zero. The counts are approximate due to */
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/* concurrency issues, but we need to ensure that a count of */
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/* zero implies an empty block. */
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# else
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hhdr -> hb_n_marks = n_marks;
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# endif
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}
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}
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GC_API int GC_CALL GC_is_marked(const void *p)
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{
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struct hblk *h = HBLKPTR(p);
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hdr * hhdr = HDR(h);
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word bit_no = MARK_BIT_NO((ptr_t)p - (ptr_t)h, hhdr -> hb_sz);
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return (int)mark_bit_from_hdr(hhdr, bit_no); /* 0 or 1 */
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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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GC_INNER void GC_clear_marks(void)
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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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}
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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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GC_INNER void GC_initiate_gc(void)
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{
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GC_ASSERT(I_HOLD_LOCK());
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# ifndef GC_DISABLE_INCREMENTAL
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if (GC_incremental) {
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# ifdef CHECKSUMS
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GC_read_dirty(FALSE);
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# else
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GC_read_dirty(GC_mark_state == MS_INVALID);
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# endif
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}
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# endif
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# ifdef CHECKSUMS
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if (GC_incremental) GC_check_dirty();
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# endif
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# if !defined(GC_DISABLE_INCREMENTAL)
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GC_n_rescuing_pages = 0;
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# endif
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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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#ifdef PARALLEL_MARK
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STATIC void GC_do_parallel_mark(void); /* initiate parallel marking. */
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#endif /* PARALLEL_MARK */
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#ifdef GC_DISABLE_INCREMENTAL
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# define GC_push_next_marked_dirty(h) GC_push_next_marked(h)
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#else
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STATIC struct hblk * GC_push_next_marked_dirty(struct hblk *h);
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/* Invoke GC_push_marked on next dirty block above h. */
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/* Return a pointer just past the end of this block. */
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#endif /* !GC_DISABLE_INCREMENTAL */
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STATIC struct hblk * GC_push_next_marked(struct hblk *h);
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/* Ditto, but also mark from clean pages. */
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STATIC struct hblk * GC_push_next_marked_uncollectable(struct hblk *h);
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/* Ditto, but mark only from uncollectible pages. */
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static void alloc_mark_stack(size_t);
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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 WRAP_MARK_SOME
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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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STATIC GC_bool GC_mark_some_inner(ptr_t cold_gc_frame)
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#else
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GC_INNER GC_bool GC_mark_some(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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break;
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case MS_PUSH_RESCUERS:
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if ((word)GC_mark_stack_top
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>= (word)(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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break;
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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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# if !defined(GC_DISABLE_INCREMENTAL)
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GC_COND_LOG_PRINTF("Marked from %lu dirty pages\n",
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(unsigned long)GC_n_rescuing_pages);
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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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break;
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case MS_PUSH_UNCOLLECTABLE:
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if ((word)GC_mark_stack_top
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>= (word)(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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break;
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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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break;
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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((word)GC_mark_stack_top < (word)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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}
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break;
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}
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# endif
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if ((word)GC_mark_stack_top >= (word)GC_mark_stack) {
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MARK_FROM_MARK_STACK();
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break;
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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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break;
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}
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if ((word)GC_mark_stack_top >= (word)GC_mark_stack) {
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MARK_FROM_MARK_STACK();
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break;
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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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break;
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default:
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ABORT("GC_mark_some: bad state");
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}
|
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return(FALSE);
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}
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|
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#ifdef WRAP_MARK_SOME
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|
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# if (defined(MSWIN32) || defined(MSWINCE)) && defined(__GNUC__)
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|
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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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|
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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 GC_ATTR_UNUSED)
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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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|
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/* Unwind from the inner function assuming the standard */
|
|
/* function prologue. */
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/* Assumes code has not been compiled with */
|
|
/* -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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|
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/* Resume execution at the "real" handler within the */
|
|
/* wrapper function. */
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context->Eip = (DWORD )(xer->alt_path);
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|
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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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}
|
|
# endif /* __GNUC__ && MSWIN32 */
|
|
|
|
GC_INNER GC_bool GC_mark_some(ptr_t cold_gc_frame)
|
|
{
|
|
GC_bool ret_val;
|
|
|
|
# if defined(MSWIN32) || defined(MSWINCE)
|
|
# ifndef __GNUC__
|
|
/* Windows 98 appears to asynchronously create and remove */
|
|
/* writable memory mappings, for reasons we haven't yet */
|
|
/* understood. Since we look for writable regions to */
|
|
/* determine the root set, we may try to mark from an */
|
|
/* address range that disappeared since we started the */
|
|
/* collection. Thus we have to recover from faults here. */
|
|
/* This code does not appear to be necessary for Windows */
|
|
/* 95/NT/2000+. Note that this code should never generate */
|
|
/* an incremental GC write fault. */
|
|
/* This code seems to be necessary for WinCE (at least in */
|
|
/* the case we'd decide to add MEM_PRIVATE sections to */
|
|
/* data roots in GC_register_dynamic_libraries()). */
|
|
/* It's conceivable that this is the same issue with */
|
|
/* terminating threads that we see with Linux and */
|
|
/* USE_PROC_FOR_LIBRARIES. */
|
|
#ifndef NO_CRT
|
|
__try {
|
|
#endif
|
|
ret_val = GC_mark_some_inner(cold_gc_frame);
|
|
#ifndef NO_CRT
|
|
} __except (GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ?
|
|
EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
|
|
goto handle_ex;
|
|
}
|
|
#endif
|
|
# if defined(GC_WIN32_THREADS) && !defined(GC_PTHREADS)
|
|
/* With DllMain-based thread tracking, a thread may have */
|
|
/* started while we were marking. This is logically equivalent */
|
|
/* to the exception case; our results are invalid and we have */
|
|
/* to start over. This cannot be prevented since we can't */
|
|
/* block in DllMain. */
|
|
if (GC_started_thread_while_stopped()) goto handle_ex;
|
|
# endif
|
|
rm_handler:
|
|
return ret_val;
|
|
|
|
# else /* __GNUC__ */
|
|
|
|
/* Manually install an exception handler since GCC does */
|
|
/* not yet support Structured Exception Handling (SEH) on */
|
|
/* Win32. */
|
|
|
|
ext_ex_regn er;
|
|
|
|
# if GC_GNUC_PREREQ(4, 7) || GC_CLANG_PREREQ(3, 3)
|
|
# pragma GCC diagnostic push
|
|
/* Suppress "taking the address of label is non-standard" warning. */
|
|
# if defined(__clang__) || GC_GNUC_PREREQ(6, 4)
|
|
# pragma GCC diagnostic ignored "-Wpedantic"
|
|
# else
|
|
/* GCC before ~4.8 does not accept "-Wpedantic" quietly. */
|
|
# pragma GCC diagnostic ignored "-pedantic"
|
|
# endif
|
|
er.alt_path = &&handle_ex;
|
|
# pragma GCC diagnostic pop
|
|
# else /* pragma diagnostic is not supported */
|
|
er.alt_path = &&handle_ex;
|
|
# endif
|
|
er.ex_reg.handler = mark_ex_handler;
|
|
__asm__ __volatile__ ("movl %%fs:0, %0" : "=r" (er.ex_reg.prev));
|
|
__asm__ __volatile__ ("movl %0, %%fs:0" : : "r" (&er));
|
|
ret_val = GC_mark_some_inner(cold_gc_frame);
|
|
/* Prevent GCC from considering the following code unreachable */
|
|
/* and thus eliminating it. */
|
|
if (er.alt_path == 0)
|
|
goto handle_ex;
|
|
# if defined(GC_WIN32_THREADS) && !defined(GC_PTHREADS)
|
|
if (GC_started_thread_while_stopped())
|
|
goto handle_ex;
|
|
# endif
|
|
rm_handler:
|
|
/* Uninstall the exception handler */
|
|
__asm__ __volatile__ ("mov %0, %%fs:0" : : "r" (er.ex_reg.prev));
|
|
return ret_val;
|
|
|
|
# endif /* __GNUC__ */
|
|
# else /* !MSWIN32 */
|
|
/* Here we are handling the case in which /proc is used for root */
|
|
/* finding, and we have threads. We may find a stack for a */
|
|
/* thread that is in the process of exiting, and disappears */
|
|
/* while we are marking it. This seems extremely difficult to */
|
|
/* avoid otherwise. */
|
|
if (GC_incremental) {
|
|
WARN("Incremental GC incompatible with /proc roots\n", 0);
|
|
/* I'm not sure if this could still work ... */
|
|
}
|
|
GC_setup_temporary_fault_handler();
|
|
if(SETJMP(GC_jmp_buf) != 0) goto handle_ex;
|
|
ret_val = GC_mark_some_inner(cold_gc_frame);
|
|
rm_handler:
|
|
GC_reset_fault_handler();
|
|
return ret_val;
|
|
|
|
# endif /* !MSWIN32 */
|
|
|
|
handle_ex:
|
|
/* Exception handler starts here for all cases. */
|
|
{
|
|
static word warned_gc_no;
|
|
|
|
/* Warn about it at most once per collection. */
|
|
if (warned_gc_no != GC_gc_no) {
|
|
warned_gc_no = GC_gc_no;
|
|
WARN("Caught ACCESS_VIOLATION in marker;"
|
|
" memory mapping disappeared\n", 0);
|
|
}
|
|
}
|
|
/* We have bad roots on the stack. Discard mark stack. */
|
|
/* Rescan from marked objects. Redetermine roots. */
|
|
# ifdef REGISTER_LIBRARIES_EARLY
|
|
START_WORLD();
|
|
GC_cond_register_dynamic_libraries();
|
|
STOP_WORLD();
|
|
# endif
|
|
GC_invalidate_mark_state();
|
|
scan_ptr = 0;
|
|
|
|
ret_val = FALSE;
|
|
goto rm_handler; /* Back to platform-specific code. */
|
|
}
|
|
#endif /* WRAP_MARK_SOME */
|
|
|
|
GC_INNER void GC_invalidate_mark_state(void)
|
|
{
|
|
GC_mark_state = MS_INVALID;
|
|
GC_mark_stack_top = GC_mark_stack-1;
|
|
}
|
|
|
|
GC_INNER mse * GC_signal_mark_stack_overflow(mse *msp)
|
|
{
|
|
GC_mark_state = MS_INVALID;
|
|
# ifdef PARALLEL_MARK
|
|
/* We are using a local_mark_stack in parallel mode, so */
|
|
/* do not signal the global mark stack to be resized. */
|
|
/* That will be done if required in GC_return_mark_stack. */
|
|
if (!GC_parallel)
|
|
GC_mark_stack_too_small = TRUE;
|
|
# else
|
|
GC_mark_stack_too_small = TRUE;
|
|
# endif
|
|
GC_COND_LOG_PRINTF("Mark stack overflow; current size = %lu entries\n",
|
|
(unsigned long)GC_mark_stack_size);
|
|
return(msp - GC_MARK_STACK_DISCARDS);
|
|
}
|
|
|
|
/*
|
|
* Mark objects pointed to by the regions described by
|
|
* mark stack entries between mark_stack and 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.
|
|
*/
|
|
GC_ATTR_NO_SANITIZE_ADDR GC_ATTR_NO_SANITIZE_MEMORY GC_ATTR_NO_SANITIZE_THREAD
|
|
GC_INNER mse * GC_mark_from(mse *mark_stack_top, mse *mark_stack,
|
|
mse *mark_stack_limit)
|
|
{
|
|
signed_word credit = HBLKSIZE; /* Remaining credit for marking work */
|
|
ptr_t current_p; /* Pointer to current candidate ptr. */
|
|
word current; /* Candidate pointer. */
|
|
ptr_t limit = 0; /* (Incl) limit of current candidate range. */
|
|
word descr;
|
|
ptr_t greatest_ha = (ptr_t)GC_greatest_plausible_heap_addr;
|
|
ptr_t least_ha = (ptr_t)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 ((word)mark_stack_top >= (word)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.w;
|
|
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;
|
|
|
|
GC_STATIC_ASSERT(GC_DS_TAGS == 0x3);
|
|
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
|
|
|| (word)(current_p + descr)
|
|
<= (word)GC_least_plausible_heap_addr
|
|
|| (word)current_p >= (word)GC_greatest_plausible_heap_addr);
|
|
# ifdef PARALLEL_MARK
|
|
# define SHARE_BYTES 2048
|
|
if (descr > SHARE_BYTES && GC_parallel
|
|
&& (word)mark_stack_top < (word)(mark_stack_limit - 1)) {
|
|
word new_size = (descr/2) & ~(word)(sizeof(word)-1);
|
|
|
|
mark_stack_top -> mse_start = current_p;
|
|
mark_stack_top -> mse_descr.w = new_size + sizeof(word);
|
|
/* makes sure we handle */
|
|
/* misaligned pointers. */
|
|
mark_stack_top++;
|
|
# ifdef ENABLE_TRACE
|
|
if ((word)GC_trace_addr >= (word)current_p
|
|
&& (word)GC_trace_addr < (word)(current_p + descr)) {
|
|
GC_log_printf("GC #%u: large section; start %p, len %lu,"
|
|
" splitting (parallel) at %p\n",
|
|
(unsigned)GC_gc_no, (void *)current_p,
|
|
(unsigned long)descr,
|
|
(void *)(current_p + new_size));
|
|
}
|
|
# endif
|
|
current_p += new_size;
|
|
descr -= new_size;
|
|
goto retry;
|
|
}
|
|
# endif /* PARALLEL_MARK */
|
|
mark_stack_top -> mse_start =
|
|
limit = current_p + WORDS_TO_BYTES(SPLIT_RANGE_WORDS-1);
|
|
mark_stack_top -> mse_descr.w =
|
|
descr - WORDS_TO_BYTES(SPLIT_RANGE_WORDS-1);
|
|
# ifdef ENABLE_TRACE
|
|
if ((word)GC_trace_addr >= (word)current_p
|
|
&& (word)GC_trace_addr < (word)(current_p + descr)) {
|
|
GC_log_printf("GC #%u: large section; start %p, len %lu,"
|
|
" splitting at %p\n",
|
|
(unsigned)GC_gc_no, (void *)current_p,
|
|
(unsigned long)descr, (void *)limit);
|
|
}
|
|
# endif
|
|
/* Make sure that pointers overlapping the two ranges are */
|
|
/* considered. */
|
|
limit += sizeof(word) - ALIGNMENT;
|
|
break;
|
|
case GC_DS_BITMAP:
|
|
mark_stack_top--;
|
|
# ifdef ENABLE_TRACE
|
|
if ((word)GC_trace_addr >= (word)current_p
|
|
&& (word)GC_trace_addr < (word)(current_p
|
|
+ WORDS_TO_BYTES(WORDSZ-2))) {
|
|
GC_log_printf("GC #%u: tracing from %p bitmap descr %lu\n",
|
|
(unsigned)GC_gc_no, (void *)current_p,
|
|
(unsigned long)descr);
|
|
}
|
|
# endif /* ENABLE_TRACE */
|
|
descr &= ~GC_DS_TAGS;
|
|
credit -= WORDS_TO_BYTES(WORDSZ/2); /* guess */
|
|
while (descr != 0) {
|
|
if ((descr & SIGNB) != 0) {
|
|
current = *(word *)current_p;
|
|
FIXUP_POINTER(current);
|
|
if (current >= (word)least_ha && current < (word)greatest_ha) {
|
|
PREFETCH((ptr_t)current);
|
|
# ifdef ENABLE_TRACE
|
|
if (GC_trace_addr == current_p) {
|
|
GC_log_printf("GC #%u: considering(3) %p -> %p\n",
|
|
(unsigned)GC_gc_no, (void *)current_p,
|
|
(void *)current);
|
|
}
|
|
# endif /* ENABLE_TRACE */
|
|
PUSH_CONTENTS((ptr_t)current, mark_stack_top,
|
|
mark_stack_limit, current_p);
|
|
}
|
|
}
|
|
descr <<= 1;
|
|
current_p += sizeof(word);
|
|
}
|
|
continue;
|
|
case GC_DS_PROC:
|
|
mark_stack_top--;
|
|
# ifdef ENABLE_TRACE
|
|
if ((word)GC_trace_addr >= (word)current_p
|
|
&& GC_base(current_p) != 0
|
|
&& GC_base(current_p) == GC_base(GC_trace_addr)) {
|
|
GC_log_printf("GC #%u: tracing from %p, proc descr %lu\n",
|
|
(unsigned)GC_gc_no, (void *)current_p,
|
|
(unsigned long)descr);
|
|
}
|
|
# endif /* ENABLE_TRACE */
|
|
credit -= GC_PROC_BYTES;
|
|
mark_stack_top = (*PROC(descr))((word *)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 *)(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 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 (EXPECT(0 == type_descr, FALSE)) {
|
|
mark_stack_top--;
|
|
continue;
|
|
}
|
|
descr = *(word *)(type_descr
|
|
- ((signed_word)descr + (GC_INDIR_PER_OBJ_BIAS
|
|
- GC_DS_PER_OBJECT)));
|
|
}
|
|
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--;
|
|
# ifndef SMALL_CONFIG
|
|
if (descr < sizeof(word))
|
|
continue;
|
|
# endif
|
|
# ifdef ENABLE_TRACE
|
|
if ((word)GC_trace_addr >= (word)current_p
|
|
&& (word)GC_trace_addr < (word)(current_p + descr)) {
|
|
GC_log_printf("GC #%u: small object; start %p, len %lu\n",
|
|
(unsigned)GC_gc_no, (void *)current_p,
|
|
(unsigned long)descr);
|
|
}
|
|
# endif
|
|
limit = current_p + (word)descr;
|
|
}
|
|
/* The simple case in which we're scanning a range. */
|
|
GC_ASSERT(!((word)current_p & (ALIGNMENT-1)));
|
|
credit -= limit - current_p;
|
|
limit -= sizeof(word);
|
|
{
|
|
# 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(limit - PREF_DIST*CACHE_LINE_SIZE);
|
|
GC_ASSERT((word)limit >= (word)current_p);
|
|
deferred = *(word *)limit;
|
|
FIXUP_POINTER(deferred);
|
|
limit -= ALIGNMENT;
|
|
if (deferred >= (word)least_ha && deferred < (word)greatest_ha) {
|
|
PREFETCH((ptr_t)deferred);
|
|
break;
|
|
}
|
|
if ((word)current_p > (word)limit) goto next_object;
|
|
/* Unroll once, so we don't do too many of the prefetches */
|
|
/* based on limit. */
|
|
deferred = *(word *)limit;
|
|
FIXUP_POINTER(deferred);
|
|
limit -= ALIGNMENT;
|
|
if (deferred >= (word)least_ha && deferred < (word)greatest_ha) {
|
|
PREFETCH((ptr_t)deferred);
|
|
break;
|
|
}
|
|
if ((word)current_p > (word)limit) goto next_object;
|
|
}
|
|
# endif
|
|
|
|
while ((word)current_p <= (word)limit) {
|
|
/* Empirically, unrolling this loop doesn't help a lot. */
|
|
/* Since PUSH_CONTENTS expands to a lot of code, */
|
|
/* we don't. */
|
|
current = *(word *)current_p;
|
|
FIXUP_POINTER(current);
|
|
PREFETCH(current_p + PREF_DIST*CACHE_LINE_SIZE);
|
|
if (current >= (word)least_ha && current < (word)greatest_ha) {
|
|
/* Prefetch the contents of the object we just pushed. It's */
|
|
/* likely we will need them soon. */
|
|
PREFETCH((ptr_t)current);
|
|
# ifdef ENABLE_TRACE
|
|
if (GC_trace_addr == current_p) {
|
|
GC_log_printf("GC #%u: considering(1) %p -> %p\n",
|
|
(unsigned)GC_gc_no, (void *)current_p,
|
|
(void *)current);
|
|
}
|
|
# endif /* ENABLE_TRACE */
|
|
PUSH_CONTENTS((ptr_t)current, mark_stack_top,
|
|
mark_stack_limit, current_p);
|
|
}
|
|
current_p += ALIGNMENT;
|
|
}
|
|
|
|
# ifndef SMALL_CONFIG
|
|
/* We still need to mark the entry we previously prefetched. */
|
|
/* We already know that it passes the preliminary pointer */
|
|
/* validity test. */
|
|
# ifdef ENABLE_TRACE
|
|
if (GC_trace_addr == current_p) {
|
|
GC_log_printf("GC #%u: considering(2) %p -> %p\n",
|
|
(unsigned)GC_gc_no, (void *)current_p,
|
|
(void *)deferred);
|
|
}
|
|
# endif /* ENABLE_TRACE */
|
|
PUSH_CONTENTS((ptr_t)deferred, mark_stack_top,
|
|
mark_stack_limit, current_p);
|
|
next_object:;
|
|
# endif
|
|
}
|
|
}
|
|
return mark_stack_top;
|
|
}
|
|
|
|
#ifdef PARALLEL_MARK
|
|
|
|
STATIC GC_bool GC_help_wanted = FALSE; /* Protected by mark lock */
|
|
STATIC unsigned GC_helper_count = 0; /* Number of running helpers. */
|
|
/* Protected by mark lock */
|
|
STATIC unsigned GC_active_count = 0; /* Number of active helpers. */
|
|
/* Protected by mark lock */
|
|
/* May increase and decrease */
|
|
/* within each mark cycle. But */
|
|
/* once it returns to 0, it */
|
|
/* stays zero for the cycle. */
|
|
|
|
GC_INNER word GC_mark_no = 0;
|
|
|
|
static mse *main_local_mark_stack;
|
|
|
|
#ifdef LINT2
|
|
# define LOCAL_MARK_STACK_SIZE (HBLKSIZE / 8)
|
|
#else
|
|
# 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. */
|
|
#endif
|
|
|
|
/* Wait all markers to finish initialization (i.e. store */
|
|
/* marker_[b]sp, marker_mach_threads, GC_marker_Id). */
|
|
GC_INNER void GC_wait_for_markers_init(void)
|
|
{
|
|
signed_word count;
|
|
|
|
if (GC_markers_m1 == 0)
|
|
return;
|
|
|
|
/* Allocate the local mark stack for the thread that holds GC lock. */
|
|
# ifndef CAN_HANDLE_FORK
|
|
GC_ASSERT(NULL == main_local_mark_stack);
|
|
# else
|
|
if (NULL == main_local_mark_stack)
|
|
# endif
|
|
{
|
|
size_t bytes_to_get =
|
|
ROUNDUP_PAGESIZE_IF_MMAP(LOCAL_MARK_STACK_SIZE * sizeof(mse));
|
|
main_local_mark_stack = (mse *)GET_MEM(bytes_to_get);
|
|
if (NULL == main_local_mark_stack)
|
|
ABORT("Insufficient memory for main local_mark_stack");
|
|
GC_add_to_our_memory((ptr_t)main_local_mark_stack, bytes_to_get);
|
|
}
|
|
|
|
/* Reuse marker lock and builders count to synchronize */
|
|
/* marker threads startup. */
|
|
GC_acquire_mark_lock();
|
|
GC_fl_builder_count += GC_markers_m1;
|
|
count = GC_fl_builder_count;
|
|
GC_release_mark_lock();
|
|
if (count != 0) {
|
|
GC_ASSERT(count > 0);
|
|
GC_wait_for_reclaim();
|
|
}
|
|
}
|
|
|
|
/* 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. */
|
|
STATIC mse * GC_steal_mark_stack(mse * low, mse * high, mse * local,
|
|
unsigned max, mse **next)
|
|
{
|
|
mse *p;
|
|
mse *top = local - 1;
|
|
unsigned i = 0;
|
|
|
|
GC_ASSERT((word)high >= (word)(low - 1)
|
|
&& (word)(high - low + 1) <= GC_mark_stack_size);
|
|
for (p = low; (word)p <= (word)high && i <= max; ++p) {
|
|
word descr = (word)AO_load(&p->mse_descr.ao);
|
|
if (descr != 0) {
|
|
/* Must be ordered after read of descr: */
|
|
AO_store_release_write(&p->mse_descr.ao, 0);
|
|
/* More than one thread may get this entry, but that's only */
|
|
/* a minor performance problem. */
|
|
++top;
|
|
top -> mse_descr.w = descr;
|
|
top -> mse_start = p -> mse_start;
|
|
GC_ASSERT((descr & GC_DS_TAGS) != GC_DS_LENGTH
|
|
|| descr < (word)GC_greatest_plausible_heap_addr
|
|
- (word)GC_least_plausible_heap_addr
|
|
|| (word)(p->mse_start + descr)
|
|
<= (word)GC_least_plausible_heap_addr
|
|
|| (word)p->mse_start
|
|
>= (word)GC_greatest_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 += (int)(descr >> 8);
|
|
}
|
|
}
|
|
*next = p;
|
|
return top;
|
|
}
|
|
|
|
/* Copy back a local mark stack. */
|
|
/* low and high are inclusive bounds. */
|
|
STATIC void GC_return_mark_stack(mse * low, mse * high)
|
|
{
|
|
mse * my_top;
|
|
mse * my_start;
|
|
size_t stack_size;
|
|
|
|
if ((word)high < (word)low) return;
|
|
stack_size = high - low + 1;
|
|
GC_acquire_mark_lock();
|
|
my_top = GC_mark_stack_top; /* Concurrent modification impossible. */
|
|
my_start = my_top + 1;
|
|
if ((word)(my_start - GC_mark_stack + stack_size)
|
|
> (word)GC_mark_stack_size) {
|
|
GC_COND_LOG_PRINTF("No room to copy back mark stack\n");
|
|
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((mse *)AO_load((volatile AO_t *)(&GC_mark_stack_top))
|
|
== my_top);
|
|
AO_store_release_write((volatile AO_t *)(&GC_mark_stack_top),
|
|
(AO_t)(my_top + stack_size));
|
|
/* Ensures visibility of previously written stack contents. */
|
|
}
|
|
GC_release_mark_lock();
|
|
GC_notify_all_marker();
|
|
}
|
|
|
|
#ifndef N_LOCAL_ITERS
|
|
# define N_LOCAL_ITERS 1
|
|
#endif
|
|
|
|
/* This function is only called when the local */
|
|
/* and the main mark stacks are both empty. */
|
|
static GC_bool has_inactive_helpers(void)
|
|
{
|
|
GC_bool res;
|
|
|
|
GC_acquire_mark_lock();
|
|
res = GC_active_count < GC_helper_count;
|
|
GC_release_mark_lock();
|
|
return res;
|
|
}
|
|
|
|
/* 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. */
|
|
/* We do not hold the mark lock. */
|
|
STATIC void GC_do_local_mark(mse *local_mark_stack, mse *local_top)
|
|
{
|
|
unsigned n;
|
|
|
|
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 ((word)local_top < (word)local_mark_stack) return;
|
|
if ((word)(local_top - local_mark_stack)
|
|
>= LOCAL_MARK_STACK_SIZE / 2) {
|
|
GC_return_mark_stack(local_mark_stack, local_top);
|
|
return;
|
|
}
|
|
}
|
|
if ((word)AO_load((volatile AO_t *)&GC_mark_stack_top)
|
|
< (word)AO_load(&GC_first_nonempty)
|
|
&& (word)local_top > (word)(local_mark_stack + 1)
|
|
&& has_inactive_helpers()) {
|
|
/* 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, even though */
|
|
/* it's harder. */
|
|
mse * new_bottom = local_mark_stack
|
|
+ (local_top - local_mark_stack)/2;
|
|
GC_ASSERT((word)new_bottom > (word)local_mark_stack
|
|
&& (word)new_bottom < (word)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);
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifndef ENTRIES_TO_GET
|
|
# define ENTRIES_TO_GET 5
|
|
#endif
|
|
|
|
/* 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 holds the mark lock. */
|
|
/* Caller has already incremented GC_helper_count. We decrement it, */
|
|
/* and maintain GC_active_count. */
|
|
STATIC void GC_mark_local(mse *local_mark_stack, int id)
|
|
{
|
|
mse * my_first_nonempty;
|
|
|
|
GC_active_count++;
|
|
my_first_nonempty = (mse *)AO_load(&GC_first_nonempty);
|
|
GC_ASSERT((word)GC_mark_stack <= (word)my_first_nonempty);
|
|
GC_ASSERT((word)my_first_nonempty
|
|
<= (word)AO_load((volatile AO_t *)&GC_mark_stack_top) + sizeof(mse));
|
|
GC_VERBOSE_LOG_PRINTF("Starting mark helper %d\n", id);
|
|
GC_release_mark_lock();
|
|
for (;;) {
|
|
size_t n_on_stack;
|
|
unsigned n_to_get;
|
|
mse * my_top;
|
|
mse * local_top;
|
|
mse * global_first_nonempty = (mse *)AO_load(&GC_first_nonempty);
|
|
|
|
GC_ASSERT((word)my_first_nonempty >= (word)GC_mark_stack &&
|
|
(word)my_first_nonempty <=
|
|
(word)AO_load((volatile AO_t *)&GC_mark_stack_top)
|
|
+ sizeof(mse));
|
|
GC_ASSERT((word)global_first_nonempty >= (word)GC_mark_stack);
|
|
if ((word)my_first_nonempty < (word)global_first_nonempty) {
|
|
my_first_nonempty = global_first_nonempty;
|
|
} else if ((word)global_first_nonempty < (word)my_first_nonempty) {
|
|
(void)AO_compare_and_swap(&GC_first_nonempty,
|
|
(AO_t)global_first_nonempty,
|
|
(AO_t)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 = (mse *)AO_load_acquire((volatile AO_t *)(&GC_mark_stack_top));
|
|
if ((word)my_top < (word)my_first_nonempty) {
|
|
GC_acquire_mark_lock();
|
|
my_top = GC_mark_stack_top;
|
|
/* Asynchronous modification impossible here, */
|
|
/* since we hold mark lock. */
|
|
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
|
|
&& (word)AO_load(&GC_first_nonempty)
|
|
> (word)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
|
|
&& (word)AO_load(&GC_first_nonempty)
|
|
> (word)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;
|
|
GC_VERBOSE_LOG_PRINTF("Finished mark helper %d\n", id);
|
|
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();
|
|
}
|
|
} else {
|
|
n_on_stack = my_top - my_first_nonempty + 1;
|
|
}
|
|
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((word)my_first_nonempty >= (word)GC_mark_stack &&
|
|
(word)my_first_nonempty <=
|
|
(word)AO_load((volatile AO_t *)&GC_mark_stack_top)
|
|
+ sizeof(mse));
|
|
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. */
|
|
STATIC void GC_do_parallel_mark(void)
|
|
{
|
|
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");
|
|
GC_VERBOSE_LOG_PRINTF("Starting marking for mark phase number %lu\n",
|
|
(unsigned long)GC_mark_no);
|
|
GC_first_nonempty = (AO_t)GC_mark_stack;
|
|
GC_active_count = 0;
|
|
GC_helper_count = 1;
|
|
GC_help_wanted = TRUE;
|
|
GC_notify_all_marker();
|
|
/* Wake up potential helpers. */
|
|
GC_mark_local(main_local_mark_stack, 0);
|
|
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 */
|
|
GC_VERBOSE_LOG_PRINTF("Finished marking for mark phase number %lu\n",
|
|
(unsigned long)GC_mark_no);
|
|
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. */
|
|
/* And we hold the mark lock. */
|
|
GC_INNER void GC_help_marker(word my_mark_no)
|
|
{
|
|
# define my_id my_id_mse.mse_descr.w
|
|
mse my_id_mse; /* align local_mark_stack explicitly */
|
|
mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
|
|
/* Note: local_mark_stack is quite big (up to 128 KiB). */
|
|
|
|
GC_ASSERT(GC_parallel);
|
|
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 > (unsigned)GC_markers_m1) {
|
|
/* Second test is useful only if original threads can also */
|
|
/* act as helpers. Under Linux they can't. */
|
|
return;
|
|
}
|
|
GC_helper_count = (unsigned)my_id + 1;
|
|
GC_mark_local(local_mark_stack, (int)my_id);
|
|
/* GC_mark_local decrements GC_helper_count. */
|
|
# undef my_id
|
|
}
|
|
|
|
#endif /* PARALLEL_MARK */
|
|
|
|
GC_INNER void GC_scratch_recycle_inner(void *ptr, size_t bytes)
|
|
{
|
|
if (ptr != NULL) {
|
|
size_t page_offset = (word)ptr & (GC_page_size - 1);
|
|
size_t displ = 0;
|
|
size_t recycled_bytes;
|
|
|
|
GC_ASSERT(bytes != 0);
|
|
GC_ASSERT(GC_page_size != 0);
|
|
/* TODO: Assert correct memory flags if GWW_VDB */
|
|
if (page_offset != 0)
|
|
displ = GC_page_size - page_offset;
|
|
recycled_bytes = (bytes - displ) & ~(GC_page_size - 1);
|
|
GC_COND_LOG_PRINTF("Recycle %lu/%lu scratch-allocated bytes at %p\n",
|
|
(unsigned long)recycled_bytes, (unsigned long)bytes,
|
|
ptr);
|
|
if (recycled_bytes > 0)
|
|
GC_add_to_heap((struct hblk *)((word)ptr + displ), recycled_bytes);
|
|
}
|
|
}
|
|
|
|
/* Allocate or reallocate space for mark stack of size n entries. */
|
|
/* May silently fail. */
|
|
static void alloc_mark_stack(size_t n)
|
|
{
|
|
mse * new_stack = (mse *)GC_scratch_alloc(n * sizeof(struct GC_ms_entry));
|
|
# ifdef GWW_VDB
|
|
/* Don't recycle a stack segment obtained with the wrong flags. */
|
|
/* Win32 GetWriteWatch requires the right kind of memory. */
|
|
static GC_bool GC_incremental_at_stack_alloc = FALSE;
|
|
GC_bool recycle_old = (!GC_incremental || GC_incremental_at_stack_alloc);
|
|
|
|
GC_incremental_at_stack_alloc = GC_incremental;
|
|
# else
|
|
# define recycle_old TRUE
|
|
# endif
|
|
|
|
GC_mark_stack_too_small = FALSE;
|
|
if (GC_mark_stack != NULL) {
|
|
if (new_stack != 0) {
|
|
if (recycle_old) {
|
|
/* Recycle old space */
|
|
GC_scratch_recycle_inner(GC_mark_stack,
|
|
GC_mark_stack_size * sizeof(struct GC_ms_entry));
|
|
}
|
|
GC_mark_stack = new_stack;
|
|
GC_mark_stack_size = n;
|
|
/* FIXME: Do we need some way to reset GC_mark_stack_size? */
|
|
GC_mark_stack_limit = new_stack + n;
|
|
GC_COND_LOG_PRINTF("Grew mark stack to %lu frames\n",
|
|
(unsigned long)GC_mark_stack_size);
|
|
} else {
|
|
WARN("Failed to grow mark stack to %" WARN_PRIdPTR " frames\n", n);
|
|
}
|
|
} else {
|
|
if (new_stack == 0) {
|
|
GC_err_printf("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;
|
|
}
|
|
|
|
GC_INNER void GC_mark_init(void)
|
|
{
|
|
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.
|
|
*/
|
|
GC_API void GC_CALL GC_push_all(void *bottom, void *top)
|
|
{
|
|
word length;
|
|
|
|
bottom = (void *)(((word)bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
|
|
top = (void *)((word)top & ~(ALIGNMENT-1));
|
|
if ((word)bottom >= (word)top) return;
|
|
|
|
GC_mark_stack_top++;
|
|
if ((word)GC_mark_stack_top >= (word)GC_mark_stack_limit) {
|
|
ABORT("Unexpected mark stack overflow");
|
|
}
|
|
length = (word)top - (word)bottom;
|
|
# if GC_DS_TAGS > ALIGNMENT - 1
|
|
length += GC_DS_TAGS;
|
|
length &= ~GC_DS_TAGS;
|
|
# endif
|
|
GC_mark_stack_top -> mse_start = (ptr_t)bottom;
|
|
GC_mark_stack_top -> mse_descr.w = length;
|
|
}
|
|
|
|
#ifndef GC_DISABLE_INCREMENTAL
|
|
|
|
/* Analogous to the above, but push only those pages h with */
|
|
/* dirty_fn(h) != 0. We use GC_push_all 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 GC_push_all pushes a small fixed */
|
|
/* number of entries. (This is invoked only if GC_push_all pushes */
|
|
/* a single entry, or if it marks each object before pushing it, thus */
|
|
/* ensuring progress in the event of a stack overflow.) */
|
|
STATIC void GC_push_selected(ptr_t bottom, ptr_t top,
|
|
GC_bool (*dirty_fn)(struct hblk *))
|
|
{
|
|
struct hblk * h;
|
|
|
|
bottom = (ptr_t)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
|
|
top = (ptr_t)(((word) top) & ~(ALIGNMENT-1));
|
|
if ((word)bottom >= (word)top) return;
|
|
|
|
h = HBLKPTR(bottom + HBLKSIZE);
|
|
if ((word)top <= (word)h) {
|
|
if ((*dirty_fn)(h-1)) {
|
|
GC_push_all(bottom, top);
|
|
}
|
|
return;
|
|
}
|
|
if ((*dirty_fn)(h-1)) {
|
|
GC_push_all(bottom, h);
|
|
}
|
|
|
|
while ((word)(h+1) <= (word)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 */
|
|
GC_push_all(h, top);
|
|
return;
|
|
} else {
|
|
GC_push_all(h, h + 1);
|
|
}
|
|
}
|
|
h++;
|
|
}
|
|
|
|
if ((ptr_t)h != top && (*dirty_fn)(h)) {
|
|
GC_push_all(h, top);
|
|
}
|
|
if ((word)GC_mark_stack_top >= (word)GC_mark_stack_limit) {
|
|
ABORT("Unexpected mark stack overflow");
|
|
}
|
|
}
|
|
|
|
GC_API void GC_CALL GC_push_conditional(void *bottom, void *top, int all)
|
|
{
|
|
if (!all) {
|
|
GC_push_selected((ptr_t)bottom, (ptr_t)top, GC_page_was_dirty);
|
|
} else {
|
|
# ifdef PROC_VDB
|
|
if (GC_incremental) {
|
|
/* Pages that were never dirtied cannot contain pointers. */
|
|
GC_push_selected((ptr_t)bottom, (ptr_t)top, GC_page_was_ever_dirty);
|
|
} else
|
|
# endif
|
|
/* else */ {
|
|
GC_push_all(bottom, top);
|
|
}
|
|
}
|
|
}
|
|
#else
|
|
GC_API void GC_CALL GC_push_conditional(void *bottom, void *top,
|
|
int all GC_ATTR_UNUSED)
|
|
{
|
|
GC_push_all(bottom, top);
|
|
}
|
|
#endif /* GC_DISABLE_INCREMENTAL */
|
|
|
|
#if defined(MSWIN32) || defined(MSWINCE)
|
|
void __cdecl GC_push_one(word p)
|
|
#else
|
|
void GC_push_one(word p)
|
|
#endif
|
|
{
|
|
GC_PUSH_ONE_STACK(p, MARKED_FROM_REGISTER);
|
|
}
|
|
|
|
GC_API struct GC_ms_entry * GC_CALL GC_mark_and_push(void *obj,
|
|
mse *mark_stack_ptr,
|
|
mse *mark_stack_limit,
|
|
void ** src GC_ATTR_UNUSED)
|
|
{
|
|
hdr * hhdr;
|
|
|
|
PREFETCH(obj);
|
|
GET_HDR(obj, hhdr);
|
|
if ((EXPECT(IS_FORWARDING_ADDR_OR_NIL(hhdr), FALSE)
|
|
&& (!GC_all_interior_pointers
|
|
|| NULL == (hhdr = GC_find_header((ptr_t)GC_base(obj)))))
|
|
|| EXPECT(HBLK_IS_FREE(hhdr), FALSE)) {
|
|
GC_ADD_TO_BLACK_LIST_NORMAL(obj, (ptr_t)src);
|
|
return mark_stack_ptr;
|
|
}
|
|
|
|
PUSH_CONTENTS_HDR(obj, mark_stack_ptr /* modified */, mark_stack_limit,
|
|
(ptr_t)src, hhdr, TRUE);
|
|
return mark_stack_ptr;
|
|
}
|
|
|
|
/* 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)
|
|
GC_INNER void GC_mark_and_push_stack(ptr_t p, ptr_t source)
|
|
# else
|
|
GC_INNER void GC_mark_and_push_stack(ptr_t p)
|
|
# define source ((ptr_t)0)
|
|
# endif
|
|
{
|
|
hdr * hhdr;
|
|
ptr_t r = p;
|
|
|
|
PREFETCH(p);
|
|
GET_HDR(p, hhdr);
|
|
if (EXPECT(IS_FORWARDING_ADDR_OR_NIL(hhdr), FALSE)
|
|
&& (NULL == hhdr
|
|
|| (r = (ptr_t)GC_base(p)) == NULL
|
|
|| (hhdr = HDR(r)) == NULL)) {
|
|
GC_ADD_TO_BLACK_LIST_STACK(p, source);
|
|
return;
|
|
}
|
|
if (EXPECT(HBLK_IS_FREE(hhdr), FALSE)) {
|
|
GC_ADD_TO_BLACK_LIST_NORMAL(p, source);
|
|
return;
|
|
}
|
|
# ifdef THREADS
|
|
/* Pointer is on the stack. We may have dirtied the object */
|
|
/* it points to, but have not called GC_dirty yet. */
|
|
GC_dirty(p); /* entire object */
|
|
# endif
|
|
PUSH_CONTENTS_HDR(r, GC_mark_stack_top, GC_mark_stack_limit,
|
|
source, hhdr, FALSE);
|
|
/* We silently ignore pointers to near the end of a block, */
|
|
/* which is very mildly suboptimal. */
|
|
/* FIXME: We should probably add a header word to address */
|
|
/* this. */
|
|
}
|
|
# undef source
|
|
|
|
#ifdef TRACE_BUF
|
|
|
|
# ifndef TRACE_ENTRIES
|
|
# define TRACE_ENTRIES 1000
|
|
# endif
|
|
|
|
struct trace_entry {
|
|
char * kind;
|
|
word gc_no;
|
|
word bytes_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].bytes_allocd = GC_bytes_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;
|
|
}
|
|
|
|
GC_API void GC_CALL GC_print_trace_inner(word gc_no)
|
|
{
|
|
int i;
|
|
|
|
for (i = GC_trace_buf_ptr-1; i != GC_trace_buf_ptr; i--) {
|
|
struct trace_entry *p;
|
|
|
|
if (i < 0) i = TRACE_ENTRIES-1;
|
|
p = GC_trace_buf + i;
|
|
if (p -> gc_no < gc_no || p -> kind == 0) {
|
|
return;
|
|
}
|
|
GC_printf("Trace:%s (gc:%u, bytes:%lu) 0x%lX, 0x%lX\n",
|
|
p -> kind, (unsigned)p -> gc_no,
|
|
(unsigned long)p -> bytes_allocd,
|
|
(long)p->arg1 ^ 0x80000000L, (long)p->arg2 ^ 0x80000000L);
|
|
}
|
|
GC_printf("Trace incomplete\n");
|
|
}
|
|
|
|
GC_API void GC_CALL GC_print_trace(word gc_no)
|
|
{
|
|
DCL_LOCK_STATE;
|
|
|
|
LOCK();
|
|
GC_print_trace_inner(gc_no);
|
|
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.
|
|
*/
|
|
GC_ATTR_NO_SANITIZE_ADDR GC_ATTR_NO_SANITIZE_MEMORY GC_ATTR_NO_SANITIZE_THREAD
|
|
GC_API void GC_CALL GC_push_all_eager(void *bottom, void *top)
|
|
{
|
|
word * b = (word *)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
|
|
word * t = (word *)(((word) top) & ~(ALIGNMENT-1));
|
|
REGISTER word *p;
|
|
REGISTER word *lim;
|
|
REGISTER ptr_t greatest_ha = (ptr_t)GC_greatest_plausible_heap_addr;
|
|
REGISTER ptr_t least_ha = (ptr_t)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; (word)p <= (word)lim;
|
|
p = (word *)(((ptr_t)p) + ALIGNMENT)) {
|
|
REGISTER word q = *p;
|
|
|
|
GC_PUSH_ONE_STACK(q, p);
|
|
}
|
|
# undef GC_greatest_plausible_heap_addr
|
|
# undef GC_least_plausible_heap_addr
|
|
}
|
|
|
|
GC_INNER void GC_push_all_stack(ptr_t bottom, ptr_t top)
|
|
{
|
|
# if defined(THREADS) && defined(MPROTECT_VDB)
|
|
GC_push_all_eager(bottom, top);
|
|
# else
|
|
# ifndef NEED_FIXUP_POINTER
|
|
if (GC_all_interior_pointers) {
|
|
GC_push_all(bottom, top);
|
|
} else
|
|
# endif
|
|
/* else */ {
|
|
GC_push_all_eager(bottom, top);
|
|
}
|
|
# endif
|
|
}
|
|
|
|
#if defined(WRAP_MARK_SOME) && defined(PARALLEL_MARK)
|
|
/* Similar to GC_push_conditional but scans the whole region immediately. */
|
|
GC_ATTR_NO_SANITIZE_ADDR GC_ATTR_NO_SANITIZE_MEMORY
|
|
GC_ATTR_NO_SANITIZE_THREAD
|
|
GC_INNER void GC_push_conditional_eager(void *bottom, void *top,
|
|
GC_bool all)
|
|
{
|
|
word * b = (word *)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
|
|
word * t = (word *)(((word) top) & ~(ALIGNMENT-1));
|
|
REGISTER word *p;
|
|
REGISTER word *lim;
|
|
REGISTER ptr_t greatest_ha = (ptr_t)GC_greatest_plausible_heap_addr;
|
|
REGISTER ptr_t least_ha = (ptr_t)GC_least_plausible_heap_addr;
|
|
# define GC_greatest_plausible_heap_addr greatest_ha
|
|
# define GC_least_plausible_heap_addr least_ha
|
|
|
|
if (top == NULL)
|
|
return;
|
|
(void)all; /* TODO: If !all then scan only dirty pages. */
|
|
|
|
lim = t - 1;
|
|
for (p = b; (word)p <= (word)lim; p = (word *)((ptr_t)p + ALIGNMENT)) {
|
|
REGISTER word q = *p;
|
|
|
|
GC_PUSH_ONE_HEAP(q, p, GC_mark_stack_top);
|
|
}
|
|
# undef GC_greatest_plausible_heap_addr
|
|
# undef GC_least_plausible_heap_addr
|
|
}
|
|
#endif /* WRAP_MARK_SOME && PARALLEL_MARK */
|
|
|
|
#if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES) && \
|
|
defined(MARK_BIT_PER_GRANULE)
|
|
# if GC_GRANULE_WORDS == 1
|
|
# define USE_PUSH_MARKED_ACCELERATORS
|
|
# define PUSH_GRANULE(q) \
|
|
do { \
|
|
word qcontents = (q)[0]; \
|
|
GC_PUSH_ONE_HEAP(qcontents, q, GC_mark_stack_top); \
|
|
} while (0)
|
|
# elif GC_GRANULE_WORDS == 2
|
|
# define USE_PUSH_MARKED_ACCELERATORS
|
|
# define PUSH_GRANULE(q) \
|
|
do { \
|
|
word qcontents = (q)[0]; \
|
|
GC_PUSH_ONE_HEAP(qcontents, q, GC_mark_stack_top); \
|
|
qcontents = (q)[1]; \
|
|
GC_PUSH_ONE_HEAP(qcontents, (q)+1, GC_mark_stack_top); \
|
|
} while (0)
|
|
# elif GC_GRANULE_WORDS == 4
|
|
# define USE_PUSH_MARKED_ACCELERATORS
|
|
# define PUSH_GRANULE(q) \
|
|
do { \
|
|
word qcontents = (q)[0]; \
|
|
GC_PUSH_ONE_HEAP(qcontents, q, GC_mark_stack_top); \
|
|
qcontents = (q)[1]; \
|
|
GC_PUSH_ONE_HEAP(qcontents, (q)+1, GC_mark_stack_top); \
|
|
qcontents = (q)[2]; \
|
|
GC_PUSH_ONE_HEAP(qcontents, (q)+2, GC_mark_stack_top); \
|
|
qcontents = (q)[3]; \
|
|
GC_PUSH_ONE_HEAP(qcontents, (q)+3, GC_mark_stack_top); \
|
|
} while (0)
|
|
# endif
|
|
#endif /* !USE_MARK_BYTES && MARK_BIT_PER_GRANULE */
|
|
|
|
#ifdef USE_PUSH_MARKED_ACCELERATORS
|
|
/* Push all objects reachable from marked objects in the given block */
|
|
/* containing objects of size 1 granule. */
|
|
STATIC void GC_push_marked1(struct hblk *h, hdr *hhdr)
|
|
{
|
|
word * mark_word_addr = &(hhdr->hb_marks[0]);
|
|
word *p;
|
|
word *plim;
|
|
|
|
/* Allow registers to be used for some frequently accessed */
|
|
/* global variables. Otherwise aliasing issues are likely */
|
|
/* to prevent that. */
|
|
ptr_t greatest_ha = (ptr_t)GC_greatest_plausible_heap_addr;
|
|
ptr_t least_ha = (ptr_t)GC_least_plausible_heap_addr;
|
|
mse * mark_stack_top = GC_mark_stack_top;
|
|
mse * mark_stack_limit = GC_mark_stack_limit;
|
|
|
|
# undef GC_mark_stack_top
|
|
# undef 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 ((word)p < (word)plim) {
|
|
word mark_word = *mark_word_addr++;
|
|
word *q = p;
|
|
|
|
while(mark_word != 0) {
|
|
if (mark_word & 1) {
|
|
PUSH_GRANULE(q);
|
|
}
|
|
q += GC_GRANULE_WORDS;
|
|
mark_word >>= 1;
|
|
}
|
|
p += WORDSZ*GC_GRANULE_WORDS;
|
|
}
|
|
|
|
# undef GC_greatest_plausible_heap_addr
|
|
# undef GC_least_plausible_heap_addr
|
|
# undef GC_mark_stack_top
|
|
# undef GC_mark_stack_limit
|
|
# define GC_mark_stack_limit GC_arrays._mark_stack_limit
|
|
# define GC_mark_stack_top GC_arrays._mark_stack_top
|
|
GC_mark_stack_top = mark_stack_top;
|
|
}
|
|
|
|
|
|
#ifndef UNALIGNED_PTRS
|
|
|
|
/* Push all objects reachable from marked objects in the given block */
|
|
/* of size 2 (granules) objects. */
|
|
STATIC void GC_push_marked2(struct hblk *h, hdr *hhdr)
|
|
{
|
|
word * mark_word_addr = &(hhdr->hb_marks[0]);
|
|
word *p;
|
|
word *plim;
|
|
|
|
ptr_t greatest_ha = (ptr_t)GC_greatest_plausible_heap_addr;
|
|
ptr_t least_ha = (ptr_t)GC_least_plausible_heap_addr;
|
|
mse * mark_stack_top = GC_mark_stack_top;
|
|
mse * mark_stack_limit = GC_mark_stack_limit;
|
|
|
|
# undef GC_mark_stack_top
|
|
# undef 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 ((word)p < (word)plim) {
|
|
word mark_word = *mark_word_addr++;
|
|
word *q = p;
|
|
|
|
while(mark_word != 0) {
|
|
if (mark_word & 1) {
|
|
PUSH_GRANULE(q);
|
|
PUSH_GRANULE(q + GC_GRANULE_WORDS);
|
|
}
|
|
q += 2 * GC_GRANULE_WORDS;
|
|
mark_word >>= 2;
|
|
}
|
|
p += WORDSZ*GC_GRANULE_WORDS;
|
|
}
|
|
|
|
# undef GC_greatest_plausible_heap_addr
|
|
# undef GC_least_plausible_heap_addr
|
|
# undef GC_mark_stack_top
|
|
# undef GC_mark_stack_limit
|
|
# define GC_mark_stack_limit GC_arrays._mark_stack_limit
|
|
# define GC_mark_stack_top GC_arrays._mark_stack_top
|
|
GC_mark_stack_top = mark_stack_top;
|
|
}
|
|
|
|
# if GC_GRANULE_WORDS < 4
|
|
/* Push all objects reachable from marked objects in the given block */
|
|
/* of size 4 (granules) 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. */
|
|
STATIC void GC_push_marked4(struct hblk *h, hdr *hhdr)
|
|
{
|
|
word * mark_word_addr = &(hhdr->hb_marks[0]);
|
|
word *p;
|
|
word *plim;
|
|
|
|
ptr_t greatest_ha = (ptr_t)GC_greatest_plausible_heap_addr;
|
|
ptr_t least_ha = (ptr_t)GC_least_plausible_heap_addr;
|
|
mse * mark_stack_top = GC_mark_stack_top;
|
|
mse * mark_stack_limit = GC_mark_stack_limit;
|
|
|
|
# undef GC_mark_stack_top
|
|
# undef 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 ((word)p < (word)plim) {
|
|
word mark_word = *mark_word_addr++;
|
|
word *q = p;
|
|
|
|
while(mark_word != 0) {
|
|
if (mark_word & 1) {
|
|
PUSH_GRANULE(q);
|
|
PUSH_GRANULE(q + GC_GRANULE_WORDS);
|
|
PUSH_GRANULE(q + 2*GC_GRANULE_WORDS);
|
|
PUSH_GRANULE(q + 3*GC_GRANULE_WORDS);
|
|
}
|
|
q += 4 * GC_GRANULE_WORDS;
|
|
mark_word >>= 4;
|
|
}
|
|
p += WORDSZ*GC_GRANULE_WORDS;
|
|
}
|
|
# undef GC_greatest_plausible_heap_addr
|
|
# undef GC_least_plausible_heap_addr
|
|
# undef GC_mark_stack_top
|
|
# undef GC_mark_stack_limit
|
|
# define GC_mark_stack_limit GC_arrays._mark_stack_limit
|
|
# define GC_mark_stack_top GC_arrays._mark_stack_top
|
|
GC_mark_stack_top = mark_stack_top;
|
|
}
|
|
|
|
#endif /* GC_GRANULE_WORDS < 4 */
|
|
|
|
#endif /* UNALIGNED_PTRS */
|
|
|
|
#endif /* USE_PUSH_MARKED_ACCELERATORS */
|
|
|
|
/* Push all objects reachable from marked objects in the given block */
|
|
STATIC void GC_push_marked(struct hblk *h, hdr *hhdr)
|
|
{
|
|
word sz = hhdr -> hb_sz;
|
|
word descr = hhdr -> hb_descr;
|
|
ptr_t p;
|
|
word bit_no;
|
|
ptr_t lim;
|
|
mse * GC_mark_stack_top_reg;
|
|
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;
|
|
# if !defined(GC_DISABLE_INCREMENTAL)
|
|
GC_n_rescuing_pages++;
|
|
# endif
|
|
GC_objects_are_marked = TRUE;
|
|
if (sz > MAXOBJBYTES) {
|
|
lim = h -> hb_body;
|
|
} else {
|
|
lim = (ptr_t)((word)(h + 1)->hb_body - sz);
|
|
}
|
|
|
|
switch(BYTES_TO_GRANULES(sz)) {
|
|
# if defined(USE_PUSH_MARKED_ACCELERATORS)
|
|
case 1:
|
|
GC_push_marked1(h, hhdr);
|
|
break;
|
|
# if !defined(UNALIGNED_PTRS)
|
|
case 2:
|
|
GC_push_marked2(h, hhdr);
|
|
break;
|
|
# if GC_GRANULE_WORDS < 4
|
|
case 4:
|
|
GC_push_marked4(h, hhdr);
|
|
break;
|
|
# endif
|
|
# endif
|
|
# endif
|
|
default:
|
|
GC_mark_stack_top_reg = GC_mark_stack_top;
|
|
for (p = h -> hb_body, bit_no = 0; (word)p <= (word)lim;
|
|
p += sz, bit_no += MARK_BIT_OFFSET(sz)) {
|
|
if (mark_bit_from_hdr(hhdr, bit_no)) {
|
|
/* Mark from fields inside the object */
|
|
PUSH_OBJ(p, hhdr, GC_mark_stack_top_reg, mark_stack_limit);
|
|
}
|
|
}
|
|
GC_mark_stack_top = GC_mark_stack_top_reg;
|
|
}
|
|
}
|
|
|
|
#ifdef ENABLE_DISCLAIM
|
|
/* Unconditionally mark from all objects which have not been reclaimed. */
|
|
/* This is useful in order to retain pointers which are reachable from */
|
|
/* the disclaim notifiers. */
|
|
/* */
|
|
/* To determine whether an object has been reclaimed, we require that */
|
|
/* any live object has a non-zero as one of the two lowest bits of the */
|
|
/* first word. On the other hand, a reclaimed object is a members of */
|
|
/* free-lists, and thus contains a word-aligned next-pointer as the */
|
|
/* first word. */
|
|
STATIC void GC_push_unconditionally(struct hblk *h, hdr *hhdr)
|
|
{
|
|
word sz = hhdr -> hb_sz;
|
|
word descr = hhdr -> hb_descr;
|
|
ptr_t p;
|
|
ptr_t lim;
|
|
mse * GC_mark_stack_top_reg;
|
|
mse * mark_stack_limit = GC_mark_stack_limit;
|
|
|
|
if ((/* 0 | */ GC_DS_LENGTH) == descr)
|
|
return;
|
|
|
|
# if !defined(GC_DISABLE_INCREMENTAL)
|
|
GC_n_rescuing_pages++;
|
|
# endif
|
|
GC_objects_are_marked = TRUE;
|
|
if (sz > MAXOBJBYTES)
|
|
lim = h -> hb_body;
|
|
else
|
|
lim = (ptr_t)((word)(h + 1)->hb_body - sz);
|
|
|
|
GC_mark_stack_top_reg = GC_mark_stack_top;
|
|
for (p = h -> hb_body; (word)p <= (word)lim; p += sz)
|
|
if ((*(word *)p & 0x3) != 0)
|
|
PUSH_OBJ(p, hhdr, GC_mark_stack_top_reg, mark_stack_limit);
|
|
GC_mark_stack_top = GC_mark_stack_top_reg;
|
|
}
|
|
#endif /* ENABLE_DISCLAIM */
|
|
|
|
#ifndef GC_DISABLE_INCREMENTAL
|
|
/* Test whether any page in the given block is dirty. */
|
|
STATIC GC_bool GC_block_was_dirty(struct hblk *h, hdr *hhdr)
|
|
{
|
|
word sz = hhdr -> hb_sz;
|
|
|
|
if (sz <= MAXOBJBYTES) {
|
|
return(GC_page_was_dirty(h));
|
|
} else {
|
|
ptr_t p = (ptr_t)h;
|
|
while ((word)p < (word)h + sz) {
|
|
if (GC_page_was_dirty((struct hblk *)p)) return(TRUE);
|
|
p += HBLKSIZE;
|
|
}
|
|
return(FALSE);
|
|
}
|
|
}
|
|
#endif /* GC_DISABLE_INCREMENTAL */
|
|
|
|
/* Similar to GC_push_marked, but skip over unallocated blocks */
|
|
/* and return address of next plausible block. */
|
|
STATIC struct hblk * GC_push_next_marked(struct hblk *h)
|
|
{
|
|
hdr * hhdr = HDR(h);
|
|
|
|
if (EXPECT(IS_FORWARDING_ADDR_OR_NIL(hhdr) || HBLK_IS_FREE(hhdr), FALSE)) {
|
|
h = GC_next_used_block(h);
|
|
if (h == 0) return(0);
|
|
hhdr = GC_find_header((ptr_t)h);
|
|
} else {
|
|
# ifdef LINT2
|
|
if (NULL == h) ABORT("Bad HDR() definition");
|
|
# endif
|
|
}
|
|
GC_push_marked(h, hhdr);
|
|
return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
|
|
}
|
|
|
|
#ifndef GC_DISABLE_INCREMENTAL
|
|
/* Identical to above, but mark only from dirty pages */
|
|
STATIC struct hblk * GC_push_next_marked_dirty(struct hblk *h)
|
|
{
|
|
hdr * hhdr = HDR(h);
|
|
|
|
if (!GC_incremental) ABORT("Dirty bits not set up");
|
|
for (;;) {
|
|
if (EXPECT(IS_FORWARDING_ADDR_OR_NIL(hhdr)
|
|
|| HBLK_IS_FREE(hhdr), FALSE)) {
|
|
h = GC_next_used_block(h);
|
|
if (h == 0) return(0);
|
|
hhdr = GC_find_header((ptr_t)h);
|
|
} else {
|
|
# ifdef LINT2
|
|
if (NULL == h) ABORT("Bad HDR() definition");
|
|
# endif
|
|
}
|
|
if (GC_block_was_dirty(h, hhdr))
|
|
break;
|
|
h += OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
|
|
hhdr = HDR(h);
|
|
}
|
|
# ifdef ENABLE_DISCLAIM
|
|
if ((hhdr -> hb_flags & MARK_UNCONDITIONALLY) != 0) {
|
|
GC_push_unconditionally(h, hhdr);
|
|
|
|
/* Then we may ask, why not also add the MARK_UNCONDITIONALLY */
|
|
/* case to GC_push_next_marked, which is also applied to */
|
|
/* uncollectible blocks? But it seems to me that the function */
|
|
/* does not need to scan uncollectible (and unconditionally */
|
|
/* marked) blocks since those are already handled in the */
|
|
/* MS_PUSH_UNCOLLECTABLE phase. */
|
|
} else
|
|
# endif
|
|
/* else */ {
|
|
GC_push_marked(h, hhdr);
|
|
}
|
|
return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
|
|
}
|
|
#endif /* !GC_DISABLE_INCREMENTAL */
|
|
|
|
/* Similar to above, but for uncollectible pages. Needed since we */
|
|
/* do not clear marks for such pages, even for full collections. */
|
|
STATIC struct hblk * GC_push_next_marked_uncollectable(struct hblk *h)
|
|
{
|
|
hdr * hhdr = HDR(h);
|
|
|
|
for (;;) {
|
|
if (EXPECT(IS_FORWARDING_ADDR_OR_NIL(hhdr)
|
|
|| HBLK_IS_FREE(hhdr), FALSE)) {
|
|
h = GC_next_used_block(h);
|
|
if (h == 0) return(0);
|
|
hhdr = GC_find_header((ptr_t)h);
|
|
} else {
|
|
# ifdef LINT2
|
|
if (NULL == h) ABORT("Bad HDR() definition");
|
|
# endif
|
|
}
|
|
if (hhdr -> hb_obj_kind == UNCOLLECTABLE) {
|
|
GC_push_marked(h, hhdr);
|
|
break;
|
|
}
|
|
# ifdef ENABLE_DISCLAIM
|
|
if ((hhdr -> hb_flags & MARK_UNCONDITIONALLY) != 0) {
|
|
GC_push_unconditionally(h, hhdr);
|
|
break;
|
|
}
|
|
# endif
|
|
h += OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
|
|
hhdr = HDR(h);
|
|
}
|
|
return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
|
|
}
|