diff options
Diffstat (limited to '')
| -rw-r--r-- | gc/mark.c | 1690 |
1 files changed, 0 insertions, 1690 deletions
diff --git a/gc/mark.c b/gc/mark.c deleted file mode 100644 index 993c8d6..0000000 --- a/gc/mark.c +++ /dev/null @@ -1,1690 +0,0 @@ - -/* - * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers - * Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. - * Copyright (c) 2000 by Hewlett-Packard Company. All rights reserved. - * - * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED - * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. - * - * Permission is hereby granted to use or copy this program - * for any purpose, provided the above notices are retained on all copies. - * Permission to modify the code and to distribute modified code is granted, - * provided the above notices are retained, and a notice that the code was - * modified is included with the above copyright notice. - * - */ - - -# include <stdio.h> -# include "private/gc_pmark.h" - -/* We put this here to minimize the risk of inlining. */ -/*VARARGS*/ -#ifdef __WATCOMC__ - void GC_noop(void *p, ...) {} -#else - void GC_noop() {} -#endif - -/* Single argument version, robust against whole program analysis. */ -void GC_noop1(x) -word x; -{ - static VOLATILE word sink; - - sink = x; -} - -/* mark_proc GC_mark_procs[MAX_MARK_PROCS] = {0} -- declared in gc_priv.h */ - -word GC_n_mark_procs = GC_RESERVED_MARK_PROCS; - -/* Initialize GC_obj_kinds properly and standard free lists properly. */ -/* This must be done statically since they may be accessed before */ -/* GC_init is called. */ -/* It's done here, since we need to deal with mark descriptors. */ -struct obj_kind GC_obj_kinds[MAXOBJKINDS] = { -/* PTRFREE */ { &GC_aobjfreelist[0], 0 /* filled in dynamically */, - 0 | GC_DS_LENGTH, FALSE, FALSE }, -/* NORMAL */ { &GC_objfreelist[0], 0, - 0 | GC_DS_LENGTH, /* Adjusted in GC_init_inner for EXTRA_BYTES */ - TRUE /* add length to descr */, TRUE }, -/* UNCOLLECTABLE */ - { &GC_uobjfreelist[0], 0, - 0 | GC_DS_LENGTH, TRUE /* add length to descr */, TRUE }, -# ifdef ATOMIC_UNCOLLECTABLE - /* AUNCOLLECTABLE */ - { &GC_auobjfreelist[0], 0, - 0 | GC_DS_LENGTH, FALSE /* add length to descr */, FALSE }, -# endif -# ifdef STUBBORN_ALLOC -/*STUBBORN*/ { &GC_sobjfreelist[0], 0, - 0 | GC_DS_LENGTH, TRUE /* add length to descr */, TRUE }, -# endif -}; - -# ifdef ATOMIC_UNCOLLECTABLE -# ifdef STUBBORN_ALLOC - int GC_n_kinds = 5; -# else - int GC_n_kinds = 4; -# endif -# else -# ifdef STUBBORN_ALLOC - int GC_n_kinds = 4; -# else - int GC_n_kinds = 3; -# endif -# endif - - -# ifndef INITIAL_MARK_STACK_SIZE -# define INITIAL_MARK_STACK_SIZE (1*HBLKSIZE) - /* INITIAL_MARK_STACK_SIZE * sizeof(mse) should be a */ - /* multiple of HBLKSIZE. */ - /* The incremental collector actually likes a larger */ - /* size, since it want to push all marked dirty objs */ - /* before marking anything new. Currently we let it */ - /* grow dynamically. */ -# endif - -/* - * Limits of stack for GC_mark routine. - * All ranges between GC_mark_stack(incl.) and GC_mark_stack_top(incl.) still - * need to be marked from. - */ - -word GC_n_rescuing_pages; /* Number of dirty pages we marked from */ - /* excludes ptrfree pages, etc. */ - -mse * GC_mark_stack; - -mse * GC_mark_stack_limit; - -word GC_mark_stack_size = 0; - -#ifdef PARALLEL_MARK - mse * VOLATILE GC_mark_stack_top; -#else - mse * GC_mark_stack_top; -#endif - -static struct hblk * scan_ptr; - -mark_state_t GC_mark_state = MS_NONE; - -GC_bool GC_mark_stack_too_small = FALSE; - -GC_bool GC_objects_are_marked = FALSE; /* Are there collectable marked */ - /* objects in the heap? */ - -/* Is a collection in progress? Note that this can return true in the */ -/* nonincremental case, if a collection has been abandoned and the */ -/* mark state is now MS_INVALID. */ -GC_bool GC_collection_in_progress() -{ - return(GC_mark_state != MS_NONE); -} - -/* clear all mark bits in the header */ -void GC_clear_hdr_marks(hhdr) -register hdr * hhdr; -{ -# ifdef USE_MARK_BYTES - BZERO(hhdr -> hb_marks, MARK_BITS_SZ); -# else - BZERO(hhdr -> hb_marks, MARK_BITS_SZ*sizeof(word)); -# endif -} - -/* Set all mark bits in the header. Used for uncollectable blocks. */ -void GC_set_hdr_marks(hhdr) -register hdr * hhdr; -{ - register int i; - - for (i = 0; i < MARK_BITS_SZ; ++i) { -# ifdef USE_MARK_BYTES - hhdr -> hb_marks[i] = 1; -# else - hhdr -> hb_marks[i] = ONES; -# endif - } -} - -/* - * Clear all mark bits associated with block h. - */ -/*ARGSUSED*/ -# if defined(__STDC__) || defined(__cplusplus) - static void clear_marks_for_block(struct hblk *h, word dummy) -# else - static void clear_marks_for_block(h, dummy) - struct hblk *h; - word dummy; -# endif -{ - register hdr * hhdr = HDR(h); - - if (IS_UNCOLLECTABLE(hhdr -> hb_obj_kind)) return; - /* Mark bit for these is cleared only once the object is */ - /* explicitly deallocated. This either frees the block, or */ - /* the bit is cleared once the object is on the free list. */ - GC_clear_hdr_marks(hhdr); -} - -/* Slow but general routines for setting/clearing/asking about mark bits */ -void GC_set_mark_bit(p) -ptr_t p; -{ - register struct hblk *h = HBLKPTR(p); - register hdr * hhdr = HDR(h); - register int word_no = (word *)p - (word *)h; - - set_mark_bit_from_hdr(hhdr, word_no); -} - -void GC_clear_mark_bit(p) -ptr_t p; -{ - register struct hblk *h = HBLKPTR(p); - register hdr * hhdr = HDR(h); - register int word_no = (word *)p - (word *)h; - - clear_mark_bit_from_hdr(hhdr, word_no); -} - -GC_bool GC_is_marked(p) -ptr_t p; -{ - register struct hblk *h = HBLKPTR(p); - register hdr * hhdr = HDR(h); - register int word_no = (word *)p - (word *)h; - - return(mark_bit_from_hdr(hhdr, word_no)); -} - - -/* - * Clear mark bits in all allocated heap blocks. This invalidates - * the marker invariant, and sets GC_mark_state to reflect this. - * (This implicitly starts marking to reestablish the invariant.) - */ -void GC_clear_marks() -{ - GC_apply_to_all_blocks(clear_marks_for_block, (word)0); - GC_objects_are_marked = FALSE; - GC_mark_state = MS_INVALID; - scan_ptr = 0; -# ifdef GATHERSTATS - /* Counters reflect currently marked objects: reset here */ - GC_composite_in_use = 0; - GC_atomic_in_use = 0; -# endif - -} - -/* Initiate a garbage collection. Initiates a full collection if the */ -/* mark state is invalid. */ -/*ARGSUSED*/ -void GC_initiate_gc() -{ - if (GC_dirty_maintained) GC_read_dirty(); -# ifdef STUBBORN_ALLOC - GC_read_changed(); -# endif -# ifdef CHECKSUMS - { - extern void GC_check_dirty(); - - if (GC_dirty_maintained) GC_check_dirty(); - } -# endif - GC_n_rescuing_pages = 0; - if (GC_mark_state == MS_NONE) { - GC_mark_state = MS_PUSH_RESCUERS; - } else if (GC_mark_state != MS_INVALID) { - ABORT("unexpected state"); - } /* else this is really a full collection, and mark */ - /* bits are invalid. */ - scan_ptr = 0; -} - - -static void alloc_mark_stack(); - -/* Perform a small amount of marking. */ -/* We try to touch roughly a page of memory. */ -/* Return TRUE if we just finished a mark phase. */ -/* Cold_gc_frame is an address inside a GC frame that */ -/* remains valid until all marking is complete. */ -/* A zero value indicates that it's OK to miss some */ -/* register values. */ -GC_bool GC_mark_some(cold_gc_frame) -ptr_t cold_gc_frame; -{ -#if defined(MSWIN32) && !defined(__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. */ - __try { -#endif /* defined(MSWIN32) && !defined(__GNUC__) */ - switch(GC_mark_state) { - case MS_NONE: - return(FALSE); - - case MS_PUSH_RESCUERS: - if (GC_mark_stack_top - >= GC_mark_stack_limit - INITIAL_MARK_STACK_SIZE/2) { - /* Go ahead and mark, even though that might cause us to */ - /* see more marked dirty objects later on. Avoid this */ - /* in the future. */ - GC_mark_stack_too_small = TRUE; - MARK_FROM_MARK_STACK(); - return(FALSE); - } else { - scan_ptr = GC_push_next_marked_dirty(scan_ptr); - if (scan_ptr == 0) { -# ifdef CONDPRINT - if (GC_print_stats) { - GC_printf1("Marked from %lu dirty pages\n", - (unsigned long)GC_n_rescuing_pages); - } -# endif - GC_push_roots(FALSE, cold_gc_frame); - GC_objects_are_marked = TRUE; - if (GC_mark_state != MS_INVALID) { - GC_mark_state = MS_ROOTS_PUSHED; - } - } - } - return(FALSE); - - case MS_PUSH_UNCOLLECTABLE: - if (GC_mark_stack_top - >= GC_mark_stack + GC_mark_stack_size/4) { -# ifdef PARALLEL_MARK - /* Avoid this, since we don't parallelize the marker */ - /* here. */ - if (GC_parallel) GC_mark_stack_too_small = TRUE; -# endif - MARK_FROM_MARK_STACK(); - return(FALSE); - } else { - scan_ptr = GC_push_next_marked_uncollectable(scan_ptr); - if (scan_ptr == 0) { - GC_push_roots(TRUE, cold_gc_frame); - GC_objects_are_marked = TRUE; - if (GC_mark_state != MS_INVALID) { - GC_mark_state = MS_ROOTS_PUSHED; - } - } - } - return(FALSE); - - case MS_ROOTS_PUSHED: -# ifdef PARALLEL_MARK - /* In the incremental GC case, this currently doesn't */ - /* quite do the right thing, since it runs to */ - /* completion. On the other hand, starting a */ - /* parallel marker is expensive, so perhaps it is */ - /* the right thing? */ - /* Eventually, incremental marking should run */ - /* asynchronously in multiple threads, without grabbing */ - /* the allocation lock. */ - if (GC_parallel) { - GC_do_parallel_mark(); - GC_ASSERT(GC_mark_stack_top < GC_first_nonempty); - GC_mark_stack_top = GC_mark_stack - 1; - if (GC_mark_stack_too_small) { - alloc_mark_stack(2*GC_mark_stack_size); - } - if (GC_mark_state == MS_ROOTS_PUSHED) { - GC_mark_state = MS_NONE; - return(TRUE); - } else { - return(FALSE); - } - } -# endif - if (GC_mark_stack_top >= GC_mark_stack) { - MARK_FROM_MARK_STACK(); - return(FALSE); - } else { - GC_mark_state = MS_NONE; - if (GC_mark_stack_too_small) { - alloc_mark_stack(2*GC_mark_stack_size); - } - return(TRUE); - } - - case MS_INVALID: - case MS_PARTIALLY_INVALID: - if (!GC_objects_are_marked) { - GC_mark_state = MS_PUSH_UNCOLLECTABLE; - return(FALSE); - } - if (GC_mark_stack_top >= GC_mark_stack) { - MARK_FROM_MARK_STACK(); - return(FALSE); - } - if (scan_ptr == 0 && GC_mark_state == MS_INVALID) { - /* About to start a heap scan for marked objects. */ - /* Mark stack is empty. OK to reallocate. */ - if (GC_mark_stack_too_small) { - alloc_mark_stack(2*GC_mark_stack_size); - } - GC_mark_state = MS_PARTIALLY_INVALID; - } - scan_ptr = GC_push_next_marked(scan_ptr); - if (scan_ptr == 0 && GC_mark_state == MS_PARTIALLY_INVALID) { - GC_push_roots(TRUE, cold_gc_frame); - GC_objects_are_marked = TRUE; - if (GC_mark_state != MS_INVALID) { - GC_mark_state = MS_ROOTS_PUSHED; - } - } - return(FALSE); - default: - ABORT("GC_mark_some: bad state"); - return(FALSE); - } -#if defined(MSWIN32) && !defined(__GNUC__) - } __except (GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ? - EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) { -# ifdef CONDPRINT - if (GC_print_stats) { - GC_printf0("Caught ACCESS_VIOLATION in marker. " - "Memory mapping disappeared.\n"); - } -# endif /* CONDPRINT */ - /* We have bad roots on the stack. Discard mark stack. */ - /* Rescan from marked objects. Redetermine roots. */ - GC_invalidate_mark_state(); - scan_ptr = 0; - return FALSE; - } -#endif /* defined(MSWIN32) && !defined(__GNUC__) */ -} - - -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 the start of the large object */ - if (hhdr -> hb_flags & IGNORE_OFF_PAGE) return(0); - 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 < GC_greatest_plausible_heap_addr - - 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; - if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) { - PREFETCH(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; - limit = (word *)((char *)limit - ALIGNMENT); - if ((ptr_t)deferred >= least_ha && (ptr_t)deferred < greatest_ha) { - PREFETCH(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; - limit = (word *)((char *)limit - ALIGNMENT); - if ((ptr_t)deferred >= least_ha && (ptr_t)deferred < greatest_ha) { - PREFETCH(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; - 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(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; - - 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); - if (descr != 0) { - *(volatile word *) &(p -> mse_descr) = 0; - ++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 < GC_greatest_plausible_heap_addr - - GC_least_plausible_heap_addr); - /* There is no synchronization here. We assume that at */ - /* least one thread will see the original descriptor. */ - /* Otherwise we need a barrier. */ - /* More than one thread may get this entry, but that's only */ - /* a minor performance problem. */ - /* 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_write_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 *)(((long) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1)); - word * t = (word *)(((long) 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 put in 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 (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; - } -# 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 (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)); -} - - |