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[Emacs-diffs] Changes to emacs/gc/mark.c [Boehm-versions]
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From: |
Dave Love |
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Subject: |
[Emacs-diffs] Changes to emacs/gc/mark.c [Boehm-versions] |
|
Date: |
Mon, 16 Jun 2003 11:20:02 -0400 |
Index: emacs/gc/mark.c
diff -c /dev/null emacs/gc/mark.c:1.2.2.1.2.1
*** /dev/null Mon Jun 16 11:20:02 2003
--- emacs/gc/mark.c Mon Jun 16 11:19:52 2003
***************
*** 0 ****
--- 1,1817 ----
+
+ /*
+ * 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"
+
+ #if defined(MSWIN32) && defined(__GNUC__)
+ # include <excpt.h>
+ #endif
+
+ /* 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. */
+ /* We hold the allocation lock. In the case of */
+ /* incremental collection, the world may not be stopped.*/
+ #ifdef MSWIN32
+ /* For win32, this is called after we establish a structured */
+ /* exception handler, in case Windows unmaps one of our root */
+ /* segments. See below. In either case, we acquire the */
+ /* allocator lock long before we get here. */
+ GC_bool GC_mark_some_inner(cold_gc_frame)
+ ptr_t cold_gc_frame;
+ #else
+ GC_bool GC_mark_some(cold_gc_frame)
+ ptr_t cold_gc_frame;
+ #endif
+ {
+ 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);
+ }
+ }
+
+
+ #ifdef MSWIN32
+
+ # ifdef __GNUC__
+
+ typedef struct {
+ EXCEPTION_REGISTRATION ex_reg;
+ void *alt_path;
+ } ext_ex_regn;
+
+
+ static EXCEPTION_DISPOSITION mark_ex_handler(
+ struct _EXCEPTION_RECORD *ex_rec,
+ void *est_frame,
+ struct _CONTEXT *context,
+ void *disp_ctxt)
+ {
+ if (ex_rec->ExceptionCode == STATUS_ACCESS_VIOLATION) {
+ ext_ex_regn *xer = (ext_ex_regn *)est_frame;
+
+ /* Unwind from the inner function assuming the standard */
+ /* function prologue. */
+ /* Assumes code has not been compiled with */
+ /* -fomit-frame-pointer. */
+ context->Esp = context->Ebp;
+ context->Ebp = *((DWORD *)context->Esp);
+ context->Esp = context->Esp - 8;
+
+ /* Resume execution at the "real" handler within the */
+ /* wrapper function. */
+ context->Eip = (DWORD )(xer->alt_path);
+
+ return ExceptionContinueExecution;
+
+ } else {
+ return ExceptionContinueSearch;
+ }
+ }
+ # endif /* __GNUC__ */
+
+
+ GC_bool GC_mark_some(cold_gc_frame)
+ ptr_t cold_gc_frame;
+ {
+ GC_bool ret_val;
+
+ # 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. */
+
+ __try {
+
+ # else /* __GNUC__ */
+
+ /* Manually install an exception handler since GCC does */
+ /* not yet support Structured Exception Handling (SEH) on */
+ /* Win32. */
+
+ ext_ex_regn er;
+
+ er.alt_path = &&handle_ex;
+ 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));
+
+ # endif /* __GNUC__ */
+
+ ret_val = GC_mark_some_inner(cold_gc_frame);
+
+ # ifndef __GNUC__
+
+ } __except (GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ?
+ EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
+
+ # else /* __GNUC__ */
+
+ /* Prevent GCC from considering the following code unreachable */
+ /* and thus eliminating it. */
+ if (er.alt_path != 0)
+ goto rm_handler;
+
+ handle_ex:
+ /* Execution resumes from here on an access violation. */
+
+ # endif /* __GNUC__ */
+
+ # 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;
+
+ ret_val = FALSE;
+
+ # ifndef __GNUC__
+
+ }
+
+ # else /* __GNUC__ */
+
+ rm_handler:
+ /* Uninstall the exception handler */
+ asm volatile ("mov %0, %%fs:0" : : "r" (er.ex_reg.prev));
+
+ # endif /* __GNUC__ */
+
+ return ret_val;
+ }
+ #endif /* MSWIN32 */
+
+
+ GC_bool GC_mark_stack_empty()
+ {
+ return(GC_mark_stack_top < GC_mark_stack);
+ }
+
+ #ifdef PROF_MARKER
+ word GC_prof_array[10];
+ # define PROF(n) GC_prof_array[n]++
+ #else
+ # define PROF(n)
+ #endif
+
+ /* Given a pointer to someplace other than a small object page or the */
+ /* first page of a large object, either: */
+ /* - return a pointer to somewhere in the first page of the large */
+ /* object, if current points to a large object. */
+ /* In this case *hhdr is replaced with a pointer to the header */
+ /* for the large object. */
+ /* - just return current if it does not point to a large object. */
+ /*ARGSUSED*/
+ ptr_t GC_find_start(current, hhdr, new_hdr_p)
+ register ptr_t current;
+ register hdr *hhdr, **new_hdr_p;
+ {
+ if (GC_all_interior_pointers) {
+ if (hhdr != 0) {
+ register ptr_t orig = current;
+
+ current = (ptr_t)HBLKPTR(current);
+ do {
+ current = current - HBLKSIZE*(word)hhdr;
+ hhdr = HDR(current);
+ } while(IS_FORWARDING_ADDR_OR_NIL(hhdr));
+ /* current points to 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 < (word)GC_greatest_plausible_heap_addr
+ - (word)GC_least_plausible_heap_addr);
+ # ifdef PARALLEL_MARK
+ # define SHARE_BYTES 2048
+ if (descr > SHARE_BYTES && GC_parallel
+ && mark_stack_top < mark_stack_limit - 1) {
+ int new_size = (descr/2) & ~(sizeof(word)-1);
+ mark_stack_top -> mse_start = current_p;
+ mark_stack_top -> mse_descr = new_size + sizeof(word);
+ /* makes sure we handle */
+ /* misaligned pointers. */
+ mark_stack_top++;
+ current_p = (word *) ((char *)current_p + new_size);
+ descr -= new_size;
+ goto retry;
+ }
+ # endif /* PARALLEL_MARK */
+ mark_stack_top -> mse_start =
+ limit = current_p + SPLIT_RANGE_WORDS-1;
+ mark_stack_top -> mse_descr =
+ descr - WORDS_TO_BYTES(SPLIT_RANGE_WORDS-1);
+ /* Make sure that pointers overlapping the two ranges are */
+ /* considered. */
+ limit = (word *)((char *)limit + sizeof(word) - ALIGNMENT);
+ break;
+ case GC_DS_BITMAP:
+ mark_stack_top--;
+ descr &= ~GC_DS_TAGS;
+ credit -= WORDS_TO_BYTES(WORDSZ/2); /* guess */
+ while (descr != 0) {
+ if ((signed_word)descr < 0) {
+ current = *current_p;
+ FIXUP_POINTER(current);
+ if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
+ PREFETCH(current);
+ HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
+ mark_stack_limit, current_p, exit1);
+ }
+ }
+ descr <<= 1;
+ ++ current_p;
+ }
+ continue;
+ case GC_DS_PROC:
+ mark_stack_top--;
+ credit -= GC_PROC_BYTES;
+ mark_stack_top =
+ (*PROC(descr))
+ (current_p, mark_stack_top,
+ mark_stack_limit, ENV(descr));
+ continue;
+ case GC_DS_PER_OBJECT:
+ if ((signed_word)descr >= 0) {
+ /* Descriptor is in the object. */
+ descr = *(word *)((ptr_t)current_p + descr - GC_DS_PER_OBJECT);
+ } else {
+ /* Descriptor is in type descriptor pointed to by first */
+ /* word in object. */
+ ptr_t type_descr = *(ptr_t *)current_p;
+ /* type_descr is either a valid pointer to the descriptor */
+ /* structure, or this object was on a free list. If it */
+ /* it was anything but the last object on the free list, */
+ /* we will misinterpret the next object on the free list as */
+ /* the type descriptor, and get a 0 GC descriptor, which */
+ /* is ideal. Unfortunately, we need to check for the last */
+ /* object case explicitly. */
+ if (0 == type_descr) {
+ /* Rarely executed. */
+ mark_stack_top--;
+ continue;
+ }
+ descr = *(word *)(type_descr
+ - (descr - (GC_DS_PER_OBJECT
+ - GC_INDIR_PER_OBJ_BIAS)));
+ }
+ if (0 == descr) {
+ /* Can happen either because we generated a 0 descriptor */
+ /* or we saw a pointer to a free object. */
+ mark_stack_top--;
+ continue;
+ }
+ goto retry;
+ }
+ } else /* Small object with length descriptor */ {
+ mark_stack_top--;
+ limit = (word *)(((ptr_t)current_p) + (word)descr);
+ }
+ /* The simple case in which we're scanning a range. */
+ GC_ASSERT(!((word)current_p & (ALIGNMENT-1)));
+ credit -= (ptr_t)limit - (ptr_t)current_p;
+ limit -= 1;
+ {
+ # define PREF_DIST 4
+
+ # ifndef SMALL_CONFIG
+ word deferred;
+
+ /* Try to prefetch the next pointer to be examined asap. */
+ /* Empirically, this also seems to help slightly without */
+ /* prefetches, at least on linux/X86. Presumably this loop */
+ /* ends up with less register pressure, and gcc thus ends up */
+ /* generating slightly better code. Overall gcc code quality */
+ /* for this loop is still not great. */
+ for(;;) {
+ PREFETCH((ptr_t)limit - PREF_DIST*CACHE_LINE_SIZE);
+ GC_ASSERT(limit >= current_p);
+ deferred = *limit;
+ FIXUP_POINTER(deferred);
+ limit = (word *)((char *)limit - ALIGNMENT);
+ if ((ptr_t)deferred >= least_ha && (ptr_t)deferred < greatest_ha) {
+ PREFETCH(deferred);
+ break;
+ }
+ if (current_p > limit) goto next_object;
+ /* Unroll once, so we don't do too many of the prefetches */
+ /* based on limit. */
+ deferred = *limit;
+ FIXUP_POINTER(deferred);
+ limit = (word *)((char *)limit - ALIGNMENT);
+ if ((ptr_t)deferred >= least_ha && (ptr_t)deferred < greatest_ha) {
+ PREFETCH(deferred);
+ break;
+ }
+ if (current_p > limit) goto next_object;
+ }
+ # endif
+
+ while (current_p <= limit) {
+ /* Empirically, unrolling this loop doesn't help a lot. */
+ /* Since HC_PUSH_CONTENTS expands to a lot of code, */
+ /* we don't. */
+ current = *current_p;
+ FIXUP_POINTER(current);
+ PREFETCH((ptr_t)current_p + PREF_DIST*CACHE_LINE_SIZE);
+ if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
+ /* Prefetch the contents of the object we just pushed. It's */
+ /* likely we will need them soon. */
+ PREFETCH(current);
+ HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
+ mark_stack_limit, current_p, exit2);
+ }
+ current_p = (word *)((char *)current_p + ALIGNMENT);
+ }
+
+ # ifndef SMALL_CONFIG
+ /* We still need to mark the entry we previously prefetched. */
+ /* We alrady know that it passes the preliminary pointer */
+ /* validity test. */
+ HC_PUSH_CONTENTS((ptr_t)deferred, mark_stack_top,
+ mark_stack_limit, current_p, exit4);
+ next_object:;
+ # endif
+ }
+ }
+ return mark_stack_top;
+ }
+
+ #ifdef PARALLEL_MARK
+
+ /* We assume we have an ANSI C Compiler. */
+ GC_bool GC_help_wanted = FALSE;
+ unsigned GC_helper_count = 0;
+ unsigned GC_active_count = 0;
+ mse * VOLATILE GC_first_nonempty;
+ word GC_mark_no = 0;
+
+ #define LOCAL_MARK_STACK_SIZE HBLKSIZE
+ /* Under normal circumstances, this is big enough to guarantee */
+ /* We don't overflow half of it in a single call to */
+ /* GC_mark_from. */
+
+
+ /* Steal mark stack entries starting at mse low into mark stack local */
+ /* until we either steal mse high, or we have max entries. */
+ /* Return a pointer to the top of the local mark stack.
*/
+ /* *next is replaced by a pointer to the next unscanned mark stack */
+ /* entry. */
+ mse * GC_steal_mark_stack(mse * low, mse * high, mse * local,
+ unsigned max, mse **next)
+ {
+ mse *p;
+ mse *top = local - 1;
+ unsigned i = 0;
+
+ /* Make sure that prior writes to the mark stack are visible. */
+ /* On some architectures, the fact that the reads are */
+ /* volatile should suffice. */
+ # if !defined(IA64) && !defined(HP_PA) && !defined(I386)
+ GC_memory_barrier();
+ # endif
+ GC_ASSERT(high >= low-1 && high - low + 1 <= GC_mark_stack_size);
+ for (p = low; p <= high && i <= max; ++p) {
+ word descr = *(volatile word *) &(p -> mse_descr);
+ /* In the IA64 memory model, the following volatile store is */
+ /* ordered after this read of descr. Thus a thread must read */
+ /* the original nonzero value. HP_PA appears to be similar, */
+ /* and if I'm reading the P4 spec correctly, X86 is probably */
+ /* also OK. In some other cases we need a barrier. */
+ # if !defined(IA64) && !defined(HP_PA) && !defined(I386)
+ GC_memory_barrier();
+ # endif
+ if (descr != 0) {
+ *(volatile word *) &(p -> mse_descr) = 0;
+ /* More than one thread may get this entry, but that's only */
+ /* a minor performance problem. */
+ ++top;
+ top -> mse_descr = descr;
+ top -> mse_start = p -> mse_start;
+ GC_ASSERT( top -> mse_descr & GC_DS_TAGS != GC_DS_LENGTH ||
+ top -> mse_descr < GC_greatest_plausible_heap_addr
+ - GC_least_plausible_heap_addr);
+ /* If this is a big object, count it as */
+ /* size/256 + 1 objects. */
+ ++i;
+ if ((descr & GC_DS_TAGS) == GC_DS_LENGTH) i += (descr >> 8);
+ }
+ }
+ *next = p;
+ return top;
+ }
+
+ /* Copy back a local mark stack. */
+ /* low and high are inclusive bounds. */
+ void GC_return_mark_stack(mse * low, mse * high)
+ {
+ mse * my_top;
+ mse * my_start;
+ size_t stack_size;
+
+ if (high < low) return;
+ stack_size = high - low + 1;
+ GC_acquire_mark_lock();
+ my_top = GC_mark_stack_top;
+ my_start = my_top + 1;
+ if (my_start - GC_mark_stack + stack_size > GC_mark_stack_size) {
+ # ifdef CONDPRINT
+ if (GC_print_stats) {
+ GC_printf0("No room to copy back mark stack.");
+ }
+ # endif
+ GC_mark_state = MS_INVALID;
+ GC_mark_stack_too_small = TRUE;
+ /* We drop the local mark stack. We'll fix things later. */
+ } else {
+ BCOPY(low, my_start, stack_size * sizeof(mse));
+ GC_ASSERT(GC_mark_stack_top = my_top);
+ # if !defined(IA64) && !defined(HP_PA)
+ GC_memory_barrier();
+ # endif
+ /* On IA64, the volatile write acts as a release barrier. */
+ GC_mark_stack_top = my_top + stack_size;
+ }
+ GC_release_mark_lock();
+ GC_notify_all_marker();
+ }
+
+ /* Mark from the local mark stack. */
+ /* On return, the local mark stack is empty. */
+ /* But this may be achieved by copying the */
+ /* local mark stack back into the global one. */
+ void GC_do_local_mark(mse *local_mark_stack, mse *local_top)
+ {
+ unsigned n;
+ # define N_LOCAL_ITERS 1
+
+ # ifdef GC_ASSERTIONS
+ /* Make sure we don't hold mark lock. */
+ GC_acquire_mark_lock();
+ GC_release_mark_lock();
+ # endif
+ for (;;) {
+ for (n = 0; n < N_LOCAL_ITERS; ++n) {
+ local_top = GC_mark_from(local_top, local_mark_stack,
+ local_mark_stack + LOCAL_MARK_STACK_SIZE);
+ if (local_top < local_mark_stack) return;
+ if (local_top - local_mark_stack >= LOCAL_MARK_STACK_SIZE/2) {
+ GC_return_mark_stack(local_mark_stack, local_top);
+ return;
+ }
+ }
+ if (GC_mark_stack_top < GC_first_nonempty &&
+ GC_active_count < GC_helper_count
+ && local_top > local_mark_stack + 1) {
+ /* Try to share the load, since the main stack is empty, */
+ /* and helper threads are waiting for a refill. */
+ /* The entries near the bottom of the stack are likely */
+ /* to require more work. Thus we return those, eventhough */
+ /* it's harder. */
+ mse * p;
+ mse * new_bottom = local_mark_stack
+ + (local_top - local_mark_stack)/2;
+ GC_ASSERT(new_bottom > local_mark_stack
+ && new_bottom < local_top);
+ GC_return_mark_stack(local_mark_stack, new_bottom - 1);
+ memmove(local_mark_stack, new_bottom,
+ (local_top - new_bottom + 1) * sizeof(mse));
+ local_top -= (new_bottom - local_mark_stack);
+ }
+ }
+ }
+
+ #define ENTRIES_TO_GET 5
+
+ long GC_markers = 2; /* Normally changed by thread-library- */
+ /* -specific code. */
+
+ /* Mark using the local mark stack until the global mark stack is empty
*/
+ /* and there are no active workers. Update GC_first_nonempty to reflect
*/
+ /* progress. */
+ /* Caller does not hold mark lock. */
+ /* Caller has already incremented GC_helper_count. We decrement it, */
+ /* and maintain GC_active_count. */
+ void GC_mark_local(mse *local_mark_stack, int id)
+ {
+ mse * my_first_nonempty;
+
+ GC_acquire_mark_lock();
+ GC_active_count++;
+ my_first_nonempty = GC_first_nonempty;
+ GC_ASSERT(GC_first_nonempty >= GC_mark_stack &&
+ GC_first_nonempty <= GC_mark_stack_top + 1);
+ # ifdef PRINTSTATS
+ GC_printf1("Starting mark helper %lu\n", (unsigned long)id);
+ # endif
+ GC_release_mark_lock();
+ for (;;) {
+ size_t n_on_stack;
+ size_t n_to_get;
+ mse *next;
+ mse * my_top;
+ mse * local_top;
+ mse * global_first_nonempty = GC_first_nonempty;
+
+ GC_ASSERT(my_first_nonempty >= GC_mark_stack &&
+ my_first_nonempty <= GC_mark_stack_top + 1);
+ GC_ASSERT(global_first_nonempty >= GC_mark_stack &&
+ global_first_nonempty <= GC_mark_stack_top + 1);
+ if (my_first_nonempty < global_first_nonempty) {
+ my_first_nonempty = global_first_nonempty;
+ } else if (global_first_nonempty < my_first_nonempty) {
+ GC_compare_and_exchange((word *)(&GC_first_nonempty),
+ (word) global_first_nonempty,
+ (word) my_first_nonempty);
+ /* If this fails, we just go ahead, without updating */
+ /* GC_first_nonempty. */
+ }
+ /* Perhaps we should also update GC_first_nonempty, if it */
+ /* is less. But that would require using atomic updates. */
+ my_top = GC_mark_stack_top;
+ n_on_stack = my_top - my_first_nonempty + 1;
+ if (0 == n_on_stack) {
+ GC_acquire_mark_lock();
+ my_top = GC_mark_stack_top;
+ n_on_stack = my_top - my_first_nonempty + 1;
+ if (0 == n_on_stack) {
+ GC_active_count--;
+ GC_ASSERT(GC_active_count <= GC_helper_count);
+ /* Other markers may redeposit objects */
+ /* on the stack. */
+ if (0 == GC_active_count) GC_notify_all_marker();
+ while (GC_active_count > 0
+ && GC_first_nonempty > GC_mark_stack_top) {
+ /* We will be notified if either GC_active_count */
+ /* reaches zero, or if more objects are pushed on */
+ /* the global mark stack. */
+ GC_wait_marker();
+ }
+ if (GC_active_count == 0 &&
+ GC_first_nonempty > GC_mark_stack_top) {
+ GC_bool need_to_notify = FALSE;
+ /* The above conditions can't be falsified while we */
+ /* hold the mark lock, since neither */
+ /* GC_active_count nor GC_mark_stack_top can */
+ /* change. GC_first_nonempty can only be */
+ /* incremented asynchronously. Thus we know that */
+ /* both conditions actually held simultaneously. */
+ GC_helper_count--;
+ if (0 == GC_helper_count) need_to_notify = TRUE;
+ # ifdef PRINTSTATS
+ GC_printf1(
+ "Finished mark helper %lu\n", (unsigned long)id);
+ # endif
+ GC_release_mark_lock();
+ if (need_to_notify) GC_notify_all_marker();
+ return;
+ }
+ /* else there's something on the stack again, or */
+ /* another helper may push something. */
+ GC_active_count++;
+ GC_ASSERT(GC_active_count > 0);
+ GC_release_mark_lock();
+ continue;
+ } else {
+ GC_release_mark_lock();
+ }
+ }
+ n_to_get = ENTRIES_TO_GET;
+ if (n_on_stack < 2 * ENTRIES_TO_GET) n_to_get = 1;
+ local_top = GC_steal_mark_stack(my_first_nonempty, my_top,
+ local_mark_stack, n_to_get,
+ &my_first_nonempty);
+ GC_ASSERT(my_first_nonempty >= GC_mark_stack &&
+ my_first_nonempty <= GC_mark_stack_top + 1);
+ GC_do_local_mark(local_mark_stack, local_top);
+ }
+ }
+
+ /* Perform Parallel mark. */
+ /* We hold the GC lock, not the mark lock. */
+ /* Currently runs until the mark stack is */
+ /* empty. */
+ void GC_do_parallel_mark()
+ {
+ mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
+ mse * local_top;
+ mse * my_top;
+
+ GC_acquire_mark_lock();
+ GC_ASSERT(I_HOLD_LOCK());
+ /* This could be a GC_ASSERT, but it seems safer to keep it on */
+ /* all the time, especially since it's cheap. */
+ if (GC_help_wanted || GC_active_count != 0 || GC_helper_count != 0)
+ ABORT("Tried to start parallel mark in bad state");
+ # ifdef PRINTSTATS
+ GC_printf1("Starting marking for mark phase number %lu\n",
+ (unsigned long)GC_mark_no);
+ # endif
+ GC_first_nonempty = GC_mark_stack;
+ GC_active_count = 0;
+ GC_helper_count = 1;
+ GC_help_wanted = TRUE;
+ GC_release_mark_lock();
+ GC_notify_all_marker();
+ /* Wake up potential helpers. */
+ GC_mark_local(local_mark_stack, 0);
+ GC_acquire_mark_lock();
+ GC_help_wanted = FALSE;
+ /* Done; clean up. */
+ while (GC_helper_count > 0) GC_wait_marker();
+ /* GC_helper_count cannot be incremented while GC_help_wanted == FALSE */
+ # ifdef PRINTSTATS
+ GC_printf1(
+ "Finished marking for mark phase number %lu\n",
+ (unsigned long)GC_mark_no);
+ # endif
+ GC_mark_no++;
+ GC_release_mark_lock();
+ GC_notify_all_marker();
+ }
+
+
+ /* Try to help out the marker, if it's running. */
+ /* We do not hold the GC lock, but the requestor does. */
+ void GC_help_marker(word my_mark_no)
+ {
+ mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
+ unsigned my_id;
+ mse * my_first_nonempty;
+
+ if (!GC_parallel) return;
+ GC_acquire_mark_lock();
+ while (GC_mark_no < my_mark_no
+ || !GC_help_wanted && GC_mark_no == my_mark_no) {
+ GC_wait_marker();
+ }
+ my_id = GC_helper_count;
+ if (GC_mark_no != my_mark_no || my_id >= GC_markers) {
+ /* Second test is useful only if original threads can also */
+ /* act as helpers. Under Linux they can't. */
+ GC_release_mark_lock();
+ return;
+ }
+ GC_helper_count = my_id + 1;
+ GC_release_mark_lock();
+ GC_mark_local(local_mark_stack, my_id);
+ /* GC_mark_local decrements GC_helper_count. */
+ }
+
+ #endif /* PARALLEL_MARK */
+
+ /* Allocate or reallocate space for mark stack of size s words */
+ /* May silently fail. */
+ static void alloc_mark_stack(n)
+ word n;
+ {
+ mse * new_stack = (mse *)GC_scratch_alloc(n * sizeof(struct GC_ms_entry));
+
+ GC_mark_stack_too_small = FALSE;
+ if (GC_mark_stack_size != 0) {
+ if (new_stack != 0) {
+ word displ = (word)GC_mark_stack & (GC_page_size - 1);
+ signed_word size = GC_mark_stack_size * sizeof(struct GC_ms_entry);
+
+ /* Recycle old space */
+ if (0 != displ) displ = GC_page_size - displ;
+ size = (size - displ) & ~(GC_page_size - 1);
+ if (size > 0) {
+ GC_add_to_heap((struct hblk *)
+ ((word)GC_mark_stack + displ), (word)size);
+ }
+ GC_mark_stack = new_stack;
+ GC_mark_stack_size = n;
+ GC_mark_stack_limit = new_stack + n;
+ # ifdef CONDPRINT
+ if (GC_print_stats) {
+ GC_printf1("Grew mark stack to %lu frames\n",
+ (unsigned long) GC_mark_stack_size);
+ }
+ # endif
+ } else {
+ # ifdef CONDPRINT
+ if (GC_print_stats) {
+ GC_printf1("Failed to grow mark stack to %lu frames\n",
+ (unsigned long) n);
+ }
+ # endif
+ }
+ } else {
+ if (new_stack == 0) {
+ GC_err_printf0("No space for mark stack\n");
+ EXIT();
+ }
+ GC_mark_stack = new_stack;
+ GC_mark_stack_size = n;
+ GC_mark_stack_limit = new_stack + n;
+ }
+ GC_mark_stack_top = GC_mark_stack-1;
+ }
+
+ void GC_mark_init()
+ {
+ alloc_mark_stack(INITIAL_MARK_STACK_SIZE);
+ }
+
+ /*
+ * Push all locations between b and t onto the mark stack.
+ * b is the first location to be checked. t is one past the last
+ * location to be checked.
+ * Should only be used if there is no possibility of mark stack
+ * overflow.
+ */
+ void GC_push_all(bottom, top)
+ ptr_t bottom;
+ ptr_t top;
+ {
+ register word length;
+
+ bottom = (ptr_t)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
+ top = (ptr_t)(((word) top) & ~(ALIGNMENT-1));
+ if (top == 0 || bottom == top) return;
+ GC_mark_stack_top++;
+ if (GC_mark_stack_top >= GC_mark_stack_limit) {
+ ABORT("unexpected mark stack overflow");
+ }
+ length = top - bottom;
+ # if GC_DS_TAGS > ALIGNMENT - 1
+ length += GC_DS_TAGS;
+ length &= ~GC_DS_TAGS;
+ # endif
+ GC_mark_stack_top -> mse_start = (word *)bottom;
+ GC_mark_stack_top -> mse_descr = length;
+ }
+
+ /*
+ * Analogous to the above, but push only those pages h with dirty_fn(h) != 0.
+ * We use push_fn to actually push the block.
+ * Used both to selectively push dirty pages, or to push a block
+ * in piecemeal fashion, to allow for more marking concurrency.
+ * Will not overflow mark stack if push_fn pushes a small fixed number
+ * of entries. (This is invoked only if push_fn pushes a single entry,
+ * or if it marks each object before pushing it, thus ensuring progress
+ * in the event of a stack overflow.)
+ */
+ void GC_push_selected(bottom, top, dirty_fn, push_fn)
+ ptr_t bottom;
+ ptr_t top;
+ int (*dirty_fn) GC_PROTO((struct hblk * h));
+ void (*push_fn) GC_PROTO((ptr_t bottom, ptr_t top));
+ {
+ register struct hblk * h;
+
+ bottom = (ptr_t)(((long) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
+ top = (ptr_t)(((long) top) & ~(ALIGNMENT-1));
+
+ if (top == 0 || bottom == top) return;
+ h = HBLKPTR(bottom + HBLKSIZE);
+ if (top <= (ptr_t) h) {
+ if ((*dirty_fn)(h-1)) {
+ (*push_fn)(bottom, top);
+ }
+ return;
+ }
+ if ((*dirty_fn)(h-1)) {
+ (*push_fn)(bottom, (ptr_t)h);
+ }
+ while ((ptr_t)(h+1) <= top) {
+ if ((*dirty_fn)(h)) {
+ if ((word)(GC_mark_stack_top - GC_mark_stack)
+ > 3 * GC_mark_stack_size / 4) {
+ /* Danger of mark stack overflow */
+ (*push_fn)((ptr_t)h, top);
+ return;
+ } else {
+ (*push_fn)((ptr_t)h, (ptr_t)(h+1));
+ }
+ }
+ h++;
+ }
+ if ((ptr_t)h != top) {
+ if ((*dirty_fn)(h)) {
+ (*push_fn)((ptr_t)h, top);
+ }
+ }
+ if (GC_mark_stack_top >= GC_mark_stack_limit) {
+ ABORT("unexpected mark stack overflow");
+ }
+ }
+
+ # ifndef SMALL_CONFIG
+
+ #ifdef PARALLEL_MARK
+ /* Break up root sections into page size chunks to better spread */
+ /* out work. */
+ GC_bool GC_true_func(struct hblk *h) { return TRUE; }
+ # define GC_PUSH_ALL(b,t) GC_push_selected(b,t,GC_true_func,GC_push_all);
+ #else
+ # define GC_PUSH_ALL(b,t) GC_push_all(b,t);
+ #endif
+
+
+ void GC_push_conditional(bottom, top, all)
+ ptr_t bottom;
+ ptr_t top;
+ int all;
+ {
+ if (all) {
+ if (GC_dirty_maintained) {
+ # ifdef PROC_VDB
+ /* Pages that were never dirtied cannot contain pointers */
+ GC_push_selected(bottom, top, GC_page_was_ever_dirty, GC_push_all);
+ # else
+ GC_push_all(bottom, top);
+ # endif
+ } else {
+ GC_push_all(bottom, top);
+ }
+ } else {
+ GC_push_selected(bottom, top, GC_page_was_dirty, GC_push_all);
+ }
+ }
+ #endif
+
+ # if defined(MSWIN32) || defined(MSWINCE)
+ void __cdecl GC_push_one(p)
+ # else
+ void GC_push_one(p)
+ # endif
+ word p;
+ {
+ GC_PUSH_ONE_STACK(p, MARKED_FROM_REGISTER);
+ }
+
+ struct GC_ms_entry *GC_mark_and_push(obj, mark_stack_ptr, mark_stack_limit,
src)
+ GC_PTR obj;
+ struct GC_ms_entry * mark_stack_ptr;
+ struct GC_ms_entry * mark_stack_limit;
+ GC_PTR *src;
+ {
+ PREFETCH(obj);
+ PUSH_CONTENTS(obj, mark_stack_ptr /* modified */, mark_stack_limit, src,
+ was_marked /* internally generated exit label */);
+ return mark_stack_ptr;
+ }
+
+ # ifdef __STDC__
+ # define BASE(p) (word)GC_base((void *)(p))
+ # else
+ # define BASE(p) (word)GC_base((char *)(p))
+ # endif
+
+ /* Mark and push (i.e. gray) a single object p onto the main */
+ /* mark stack. Consider p to be valid if it is an interior */
+ /* pointer. */
+ /* The object p has passed a preliminary pointer validity */
+ /* test, but we do not definitely know whether it is valid. */
+ /* Mark bits are NOT atomically updated. Thus this must be the */
+ /* only thread setting them. */
+ # if defined(PRINT_BLACK_LIST) || defined(KEEP_BACK_PTRS)
+ void GC_mark_and_push_stack(p, source)
+ ptr_t source;
+ # else
+ void GC_mark_and_push_stack(p)
+ # define source 0
+ # endif
+ register word p;
+ {
+ register word r;
+ register hdr * hhdr;
+ register int displ;
+
+ GET_HDR(p, hhdr);
+ if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
+ if (hhdr != 0) {
+ r = BASE(p);
+ hhdr = HDR(r);
+ displ = BYTES_TO_WORDS(HBLKDISPL(r));
+ }
+ } else {
+ register map_entry_type map_entry;
+
+ displ = HBLKDISPL(p);
+ map_entry = MAP_ENTRY((hhdr -> hb_map), displ);
+ if (map_entry >= MAX_OFFSET) {
+ if (map_entry == OFFSET_TOO_BIG || !GC_all_interior_pointers) {
+ r = BASE(p);
+ displ = BYTES_TO_WORDS(HBLKDISPL(r));
+ if (r == 0) hhdr = 0;
+ } else {
+ /* Offset invalid, but map reflects interior pointers */
+ hhdr = 0;
+ }
+ } else {
+ displ = BYTES_TO_WORDS(displ);
+ displ -= map_entry;
+ r = (word)((word *)(HBLKPTR(p)) + displ);
+ }
+ }
+ /* If hhdr != 0 then r == GC_base(p), only we did it faster. */
+ /* displ is the word index within the block. */
+ if (hhdr == 0) {
+ # ifdef PRINT_BLACK_LIST
+ GC_add_to_black_list_stack(p, source);
+ # else
+ GC_add_to_black_list_stack(p);
+ # endif
+ # undef source /* In case we had to define it. */
+ } else {
+ if (!mark_bit_from_hdr(hhdr, displ)) {
+ set_mark_bit_from_hdr(hhdr, displ);
+ GC_STORE_BACK_PTR(source, (ptr_t)r);
+ PUSH_OBJ((word *)r, hhdr, GC_mark_stack_top,
+ GC_mark_stack_limit);
+ }
+ }
+ }
+
+ # ifdef TRACE_BUF
+
+ # define TRACE_ENTRIES 1000
+
+ struct trace_entry {
+ char * kind;
+ word gc_no;
+ word words_allocd;
+ word arg1;
+ word arg2;
+ } GC_trace_buf[TRACE_ENTRIES];
+
+ int GC_trace_buf_ptr = 0;
+
+ void GC_add_trace_entry(char *kind, word arg1, word arg2)
+ {
+ GC_trace_buf[GC_trace_buf_ptr].kind = kind;
+ GC_trace_buf[GC_trace_buf_ptr].gc_no = GC_gc_no;
+ GC_trace_buf[GC_trace_buf_ptr].words_allocd = GC_words_allocd;
+ GC_trace_buf[GC_trace_buf_ptr].arg1 = arg1 ^ 0x80000000;
+ GC_trace_buf[GC_trace_buf_ptr].arg2 = arg2 ^ 0x80000000;
+ GC_trace_buf_ptr++;
+ if (GC_trace_buf_ptr >= TRACE_ENTRIES) GC_trace_buf_ptr = 0;
+ }
+
+ void GC_print_trace(word gc_no, GC_bool lock)
+ {
+ int i;
+ struct trace_entry *p;
+
+ if (lock) LOCK();
+ for (i = GC_trace_buf_ptr-1; i != GC_trace_buf_ptr; i--) {
+ if (i < 0) i = TRACE_ENTRIES-1;
+ p = GC_trace_buf + i;
+ if (p -> gc_no < gc_no || p -> kind == 0) return;
+ printf("Trace:%s (gc:%d,words:%d) 0x%X, 0x%X\n",
+ p -> kind, p -> gc_no, p -> words_allocd,
+ (p -> arg1) ^ 0x80000000, (p -> arg2) ^ 0x80000000);
+ }
+ printf("Trace incomplete\n");
+ if (lock) UNLOCK();
+ }
+
+ # endif /* TRACE_BUF */
+
+ /*
+ * A version of GC_push_all that treats all interior pointers as valid
+ * and scans the entire region immediately, in case the contents
+ * change.
+ */
+ void GC_push_all_eager(bottom, top)
+ ptr_t bottom;
+ ptr_t top;
+ {
+ word * b = (word *)(((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 push if they appear */
+ /* to be valid. */
+ lim = t - 1 /* longword */;
+ for (p = b; p <= lim; p = (word *)(((char *)p) + ALIGNMENT)) {
+ q = *p;
+ GC_PUSH_ONE_STACK(q, p);
+ }
+ # undef GC_greatest_plausible_heap_addr
+ # undef GC_least_plausible_heap_addr
+ }
+
+ #ifndef THREADS
+ /*
+ * A version of GC_push_all that treats all interior pointers as valid
+ * and scans part of the area immediately, to make sure that saved
+ * register values are not lost.
+ * Cold_gc_frame delimits the stack section that must be scanned
+ * eagerly. A zero value indicates that no eager scanning is needed.
+ */
+ void GC_push_all_stack_partially_eager(bottom, top, cold_gc_frame)
+ ptr_t bottom;
+ ptr_t top;
+ ptr_t cold_gc_frame;
+ {
+ if (!NEED_FIXUP_POINTER && GC_all_interior_pointers) {
+ # define EAGER_BYTES 1024
+ /* Push the hot end of the stack eagerly, so that register values */
+ /* saved inside GC frames are marked before they disappear.
*/
+ /* The rest of the marking can be deferred until later. */
+ if (0 == cold_gc_frame) {
+ GC_push_all_stack(bottom, top);
+ return;
+ }
+ GC_ASSERT(bottom <= cold_gc_frame && cold_gc_frame <= top);
+ # ifdef STACK_GROWS_DOWN
+ GC_push_all(cold_gc_frame - sizeof(ptr_t), top);
+ GC_push_all_eager(bottom, cold_gc_frame);
+ # else /* STACK_GROWS_UP */
+ GC_push_all(bottom, cold_gc_frame + sizeof(ptr_t));
+ GC_push_all_eager(cold_gc_frame, top);
+ # endif /* STACK_GROWS_UP */
+ } else {
+ GC_push_all_eager(bottom, top);
+ }
+ # ifdef TRACE_BUF
+ GC_add_trace_entry("GC_push_all_stack", bottom, top);
+ # endif
+ }
+ #endif /* !THREADS */
+
+ void GC_push_all_stack(bottom, top)
+ ptr_t bottom;
+ ptr_t top;
+ {
+ if (!NEED_FIXUP_POINTER && GC_all_interior_pointers) {
+ GC_push_all(bottom, top);
+ } else {
+ GC_push_all_eager(bottom, top);
+ }
+ }
+
+ #if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
+ /* Push all objects reachable from marked objects in the given block */
+ /* of size 1 objects. */
+ void GC_push_marked1(h, hhdr)
+ struct hblk *h;
+ register hdr * hhdr;
+ {
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
+ register word *p;
+ word *plim;
+ register int i;
+ register word q;
+ register word mark_word;
+ register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
+ register ptr_t least_ha = GC_least_plausible_heap_addr;
+ register mse * mark_stack_top = GC_mark_stack_top;
+ register mse * mark_stack_limit = GC_mark_stack_limit;
+ # define GC_mark_stack_top mark_stack_top
+ # define GC_mark_stack_limit mark_stack_limit
+ # define GC_greatest_plausible_heap_addr greatest_ha
+ # define GC_least_plausible_heap_addr least_ha
+
+ p = (word *)(h->hb_body);
+ plim = (word *)(((word)h) + HBLKSIZE);
+
+ /* go through all words in block */
+ while( p < plim ) {
+ mark_word = *mark_word_addr++;
+ i = 0;
+ while(mark_word != 0) {
+ if (mark_word & 1) {
+ q = p[i];
+ GC_PUSH_ONE_HEAP(q, p + i);
+ }
+ i++;
+ mark_word >>= 1;
+ }
+ p += WORDSZ;
+ }
+ # undef GC_greatest_plausible_heap_addr
+ # undef GC_least_plausible_heap_addr
+ # undef GC_mark_stack_top
+ # undef GC_mark_stack_limit
+ GC_mark_stack_top = mark_stack_top;
+ }
+
+
+ #ifndef UNALIGNED
+
+ /* Push all objects reachable from marked objects in the given block */
+ /* of size 2 objects. */
+ void GC_push_marked2(h, hhdr)
+ struct hblk *h;
+ register hdr * hhdr;
+ {
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
+ register word *p;
+ word *plim;
+ register int i;
+ register word q;
+ register word mark_word;
+ register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
+ register ptr_t least_ha = GC_least_plausible_heap_addr;
+ register mse * mark_stack_top = GC_mark_stack_top;
+ register mse * mark_stack_limit = GC_mark_stack_limit;
+ # define GC_mark_stack_top mark_stack_top
+ # define GC_mark_stack_limit mark_stack_limit
+ # define GC_greatest_plausible_heap_addr greatest_ha
+ # define GC_least_plausible_heap_addr least_ha
+
+ p = (word *)(h->hb_body);
+ plim = (word *)(((word)h) + HBLKSIZE);
+
+ /* go through all words in block */
+ while( p < plim ) {
+ mark_word = *mark_word_addr++;
+ i = 0;
+ while(mark_word != 0) {
+ if (mark_word & 1) {
+ q = p[i];
+ GC_PUSH_ONE_HEAP(q, p + i);
+ q = p[i+1];
+ GC_PUSH_ONE_HEAP(q, p + i);
+ }
+ i += 2;
+ mark_word >>= 2;
+ }
+ p += WORDSZ;
+ }
+ # undef GC_greatest_plausible_heap_addr
+ # undef GC_least_plausible_heap_addr
+ # undef GC_mark_stack_top
+ # undef GC_mark_stack_limit
+ GC_mark_stack_top = mark_stack_top;
+ }
+
+ /* Push all objects reachable from marked objects in the given block */
+ /* of size 4 objects. */
+ /* There is a risk of mark stack overflow here. But we handle that. */
+ /* And only unmarked objects get pushed, so it's not very likely. */
+ void GC_push_marked4(h, hhdr)
+ struct hblk *h;
+ register hdr * hhdr;
+ {
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
+ register word *p;
+ word *plim;
+ register int i;
+ register word q;
+ register word mark_word;
+ register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
+ register ptr_t least_ha = GC_least_plausible_heap_addr;
+ register mse * mark_stack_top = GC_mark_stack_top;
+ register mse * mark_stack_limit = GC_mark_stack_limit;
+ # define GC_mark_stack_top mark_stack_top
+ # define GC_mark_stack_limit mark_stack_limit
+ # define GC_greatest_plausible_heap_addr greatest_ha
+ # define GC_least_plausible_heap_addr least_ha
+
+ p = (word *)(h->hb_body);
+ plim = (word *)(((word)h) + HBLKSIZE);
+
+ /* go through all words in block */
+ while( p < plim ) {
+ mark_word = *mark_word_addr++;
+ i = 0;
+ while(mark_word != 0) {
+ if (mark_word & 1) {
+ q = p[i];
+ GC_PUSH_ONE_HEAP(q, p + i);
+ q = p[i+1];
+ GC_PUSH_ONE_HEAP(q, p + i + 1);
+ q = p[i+2];
+ GC_PUSH_ONE_HEAP(q, p + i + 2);
+ q = p[i+3];
+ GC_PUSH_ONE_HEAP(q, p + i + 3);
+ }
+ i += 4;
+ mark_word >>= 4;
+ }
+ p += WORDSZ;
+ }
+ # undef GC_greatest_plausible_heap_addr
+ # undef GC_least_plausible_heap_addr
+ # undef GC_mark_stack_top
+ # undef GC_mark_stack_limit
+ GC_mark_stack_top = mark_stack_top;
+ }
+
+ #endif /* UNALIGNED */
+
+ #endif /* SMALL_CONFIG */
+
+ /* Push all objects reachable from marked objects in the given block */
+ void GC_push_marked(h, hhdr)
+ struct hblk *h;
+ register hdr * hhdr;
+ {
+ register int sz = hhdr -> hb_sz;
+ register int descr = hhdr -> hb_descr;
+ register word * p;
+ register int word_no;
+ register word * lim;
+ register mse * GC_mark_stack_top_reg;
+ register mse * mark_stack_limit = GC_mark_stack_limit;
+
+ /* Some quick shortcuts: */
+ if ((0 | GC_DS_LENGTH) == descr) return;
+ if (GC_block_empty(hhdr)/* nothing marked */) return;
+ GC_n_rescuing_pages++;
+ GC_objects_are_marked = TRUE;
+ if (sz > MAXOBJSZ) {
+ lim = (word *)h;
+ } else {
+ lim = (word *)(h + 1) - sz;
+ }
+
+ switch(sz) {
+ # if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
+ case 1:
+ GC_push_marked1(h, hhdr);
+ break;
+ # endif
+ # if !defined(SMALL_CONFIG) && !defined(UNALIGNED) && \
+ !defined(USE_MARK_BYTES)
+ case 2:
+ GC_push_marked2(h, hhdr);
+ break;
+ case 4:
+ GC_push_marked4(h, hhdr);
+ break;
+ # endif
+ default:
+ GC_mark_stack_top_reg = GC_mark_stack_top;
+ for (p = (word *)h, word_no = 0; p <= lim; p += sz, word_no += sz) {
+ if (mark_bit_from_hdr(hhdr, word_no)) {
+ /* Mark from fields inside the object */
+ PUSH_OBJ((word *)p, hhdr, GC_mark_stack_top_reg,
mark_stack_limit);
+ # ifdef GATHERSTATS
+ /* Subtract this object from total, since it was */
+ /* added in twice. */
+ GC_composite_in_use -= sz;
+ # endif
+ }
+ }
+ GC_mark_stack_top = GC_mark_stack_top_reg;
+ }
+ }
+
+ #ifndef SMALL_CONFIG
+ /* Test whether any page in the given block is dirty */
+ GC_bool GC_block_was_dirty(h, hhdr)
+ struct hblk *h;
+ register hdr * hhdr;
+ {
+ register int sz = hhdr -> hb_sz;
+
+ if (sz < MAXOBJSZ) {
+ return(GC_page_was_dirty(h));
+ } else {
+ register ptr_t p = (ptr_t)h;
+ sz = WORDS_TO_BYTES(sz);
+ while (p < (ptr_t)h + sz) {
+ if (GC_page_was_dirty((struct hblk *)p)) return(TRUE);
+ p += HBLKSIZE;
+ }
+ return(FALSE);
+ }
+ }
+ #endif /* SMALL_CONFIG */
+
+ /* Similar to GC_push_next_marked, but return address of next block */
+ struct hblk * GC_push_next_marked(h)
+ struct hblk *h;
+ {
+ register hdr * hhdr;
+
+ h = GC_next_used_block(h);
+ if (h == 0) return(0);
+ hhdr = HDR(h);
+ GC_push_marked(h, hhdr);
+ return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
+ }
+
+ #ifndef SMALL_CONFIG
+ /* Identical to above, but mark only from dirty pages */
+ struct hblk * GC_push_next_marked_dirty(h)
+ struct hblk *h;
+ {
+ register hdr * hhdr;
+
+ if (!GC_dirty_maintained) { ABORT("dirty bits not set up"); }
+ for (;;) {
+ h = GC_next_used_block(h);
+ if (h == 0) return(0);
+ hhdr = HDR(h);
+ # ifdef STUBBORN_ALLOC
+ if (hhdr -> hb_obj_kind == STUBBORN) {
+ if (GC_page_was_changed(h) && GC_block_was_dirty(h, hhdr)) {
+ break;
+ }
+ } else {
+ if (GC_block_was_dirty(h, hhdr)) break;
+ }
+ # else
+ if (GC_block_was_dirty(h, hhdr)) break;
+ # endif
+ h += OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
+ }
+ GC_push_marked(h, hhdr);
+ return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
+ }
+ #endif
+
+ /* Similar to above, but for uncollectable pages. Needed since we */
+ /* do not clear marks for such pages, even for full collections. */
+ struct hblk * GC_push_next_marked_uncollectable(h)
+ struct hblk *h;
+ {
+ register hdr * hhdr = HDR(h);
+
+ for (;;) {
+ h = GC_next_used_block(h);
+ if (h == 0) return(0);
+ hhdr = HDR(h);
+ if (hhdr -> hb_obj_kind == UNCOLLECTABLE) break;
+ h += OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
+ }
+ GC_push_marked(h, hhdr);
+ return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
+ }
+
+
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