/*
* 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.
# include <stdio.h>
-# include "gc_priv.h"
-# include "gc_mark.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*/
-void GC_noop() {}
+#ifdef __WATCOMC__
+ void GC_noop(void *p, ...) {}
+#else
+ void GC_noop() {}
+#endif
/* Single argument version, robust against whole program analysis. */
void GC_noop1(x)
sink = x;
}
-mark_proc GC_mark_procs[MAX_MARK_PROCS] = {0};
-word GC_n_mark_procs = 0;
+/* 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 */
/* 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 | DS_LENGTH, FALSE, FALSE },
+ 0 | GC_DS_LENGTH, FALSE, FALSE },
/* NORMAL */ { &GC_objfreelist[0], 0,
-# if defined(ADD_BYTE_AT_END) && ALIGNMENT > DS_TAGS
- (word)(-ALIGNMENT) | DS_LENGTH,
-# else
- 0 | DS_LENGTH,
-# endif
+ 0 | GC_DS_LENGTH, /* Adjusted in GC_init_inner for EXTRA_BYTES */
TRUE /* add length to descr */, TRUE },
/* UNCOLLECTABLE */
{ &GC_uobjfreelist[0], 0,
- 0 | DS_LENGTH, TRUE /* add length to descr */, TRUE },
+ 0 | GC_DS_LENGTH, TRUE /* add length to descr */, TRUE },
# ifdef ATOMIC_UNCOLLECTABLE
/* AUNCOLLECTABLE */
{ &GC_auobjfreelist[0], 0,
- 0 | DS_LENGTH, FALSE /* add length to descr */, FALSE },
+ 0 | GC_DS_LENGTH, FALSE /* add length to descr */, FALSE },
# endif
# ifdef STUBBORN_ALLOC
/*STUBBORN*/ { &GC_sobjfreelist[0], 0,
- 0 | DS_LENGTH, TRUE /* add length to descr */, TRUE },
+ 0 | GC_DS_LENGTH, TRUE /* add length to descr */, TRUE },
# endif
};
# 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
/*
mse * GC_mark_stack;
+mse * GC_mark_stack_limit;
+
word GC_mark_stack_size = 0;
-mse * GC_mark_stack_top;
+#ifdef PARALLEL_MARK
+ mse * VOLATILE GC_mark_stack_top;
+#else
+ mse * GC_mark_stack_top;
+#endif
static struct hblk * scan_ptr;
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);
void GC_clear_hdr_marks(hhdr)
register hdr * hhdr;
{
- BZERO(hhdr -> hb_marks, MARK_BITS_SZ*sizeof(word));
+# 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. */
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*/
-static void clear_marks_for_block(h, dummy)
-struct hblk *h;
-word dummy;
+# 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 (GC_dirty_maintained) GC_check_dirty();
}
# endif
-# ifdef GATHERSTATS
- GC_n_rescuing_pages = 0;
-# 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) {
/* Perform a small amount of marking. */
/* We try to touch roughly a page of memory. */
/* Return TRUE if we just finished a mark phase. */
-GC_bool GC_mark_some()
+/* 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:
case MS_PUSH_RESCUERS:
if (GC_mark_stack_top
- >= GC_mark_stack + INITIAL_MARK_STACK_SIZE/4) {
- GC_mark_from_mark_stack();
+ >= 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 PRINTSTATS
+# 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);
+ GC_push_roots(FALSE, cold_gc_frame);
GC_objects_are_marked = TRUE;
if (GC_mark_state != MS_INVALID) {
GC_mark_state = MS_ROOTS_PUSHED;
case MS_PUSH_UNCOLLECTABLE:
if (GC_mark_stack_top
- >= GC_mark_stack + INITIAL_MARK_STACK_SIZE/4) {
- GC_mark_from_mark_stack();
+ >= 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);
+ 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) {
- GC_mark_from_mark_stack();
+ MARK_FROM_MARK_STACK();
return(FALSE);
} else {
GC_mark_state = MS_NONE;
return(FALSE);
}
if (GC_mark_stack_top >= GC_mark_stack) {
- GC_mark_from_mark_stack();
+ MARK_FROM_MARK_STACK();
return(FALSE);
}
- if (scan_ptr == 0
- && (GC_mark_state == MS_INVALID || GC_mark_stack_too_small)) {
- alloc_mark_stack(2*GC_mark_stack_size);
+ 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);
+ GC_push_roots(TRUE, cold_gc_frame);
GC_objects_are_marked = TRUE;
if (GC_mark_state != MS_INVALID) {
GC_mark_state = MS_ROOTS_PUSHED;
}
+#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);
#endif
/* Given a pointer to someplace other than a small object page or the */
-/* first page of a large object, return a pointer either to the */
-/* start of the large object or NIL. */
-/* In the latter case black list the address current. */
-/* Returns NIL without black listing if current points to a block */
-/* with IGNORE_OFF_PAGE set. */
+/* 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*/
-# ifdef PRINT_BLACK_LIST
- word GC_find_start(current, hhdr, source)
- word source;
-# else
- word GC_find_start(current, hhdr)
-# define source 0
-# endif
-register word current;
-register hdr * hhdr;
+ptr_t GC_find_start(current, hhdr, new_hdr_p)
+register ptr_t current;
+register hdr *hhdr, **new_hdr_p;
{
-# ifdef ALL_INTERIOR_POINTERS
+ if (GC_all_interior_pointers) {
if (hhdr != 0) {
- register word orig = current;
+ register ptr_t orig = current;
- current = (word)HBLKPTR(current) + HDR_BYTES;
+ 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);
+ /* current points to near the start of the large object */
+ if (hhdr -> hb_flags & IGNORE_OFF_PAGE) return(orig);
if ((word *)orig - (word *)current
>= (ptrdiff_t)(hhdr->hb_sz)) {
/* Pointer past the end of the block */
- GC_ADD_TO_BLACK_LIST_NORMAL(orig, source);
- return(0);
+ return(orig);
}
+ *new_hdr_p = hhdr;
return(current);
} else {
- GC_ADD_TO_BLACK_LIST_NORMAL(current, source);
- return(0);
+ return(current);
}
-# else
- GC_ADD_TO_BLACK_LIST_NORMAL(current, source);
- return(0);
-# endif
-# undef source
+ } else {
+ return(current);
+ }
}
void GC_invalidate_mark_state()
mse * msp;
{
GC_mark_state = MS_INVALID;
-# ifdef PRINTSTATS
+ 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-INITIAL_MARK_STACK_SIZE/8);
+ }
+# 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,
* 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.
*/
-void GC_mark_from_mark_stack()
+mse * GC_mark_from(mark_stack_top, mark_stack, mark_stack_limit)
+mse * mark_stack_top;
+mse * mark_stack;
+mse * mark_stack_limit;
{
- mse * GC_mark_stack_reg = GC_mark_stack;
- mse * GC_mark_stack_top_reg = GC_mark_stack_top;
- mse * mark_stack_limit = &(GC_mark_stack[GC_mark_stack_size]);
int credit = HBLKSIZE; /* Remaining credit for marking work */
register word * current_p; /* Pointer to current candidate ptr. */
register word current; /* Candidate pointer. */
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 (GC_mark_stack_top_reg >= GC_mark_stack_reg && credit >= 0) {
+ while (mark_stack_top >= mark_stack && credit >= 0) {
# else
- while ((((ptr_t)GC_mark_stack_top_reg - (ptr_t)GC_mark_stack_reg) | credit)
+ while ((((ptr_t)mark_stack_top - (ptr_t)mark_stack) | credit)
>= 0) {
# endif
- current_p = GC_mark_stack_top_reg -> mse_start;
+ current_p = mark_stack_top -> mse_start;
+ descr = mark_stack_top -> mse_descr;
retry:
- descr = GC_mark_stack_top_reg -> mse_descr;
- if (descr & ((~(WORDS_TO_BYTES(SPLIT_RANGE_WORDS) - 1)) | DS_TAGS)) {
- word tag = descr & DS_TAGS;
+ /* 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 DS_LENGTH:
+ case GC_DS_LENGTH:
/* Large length. */
/* Process part of the range to avoid pushing too much on the */
/* stack. */
- GC_mark_stack_top_reg -> mse_start =
+ 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;
- GC_mark_stack_top_reg -> mse_descr -=
- WORDS_TO_BYTES(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 DS_BITMAP:
- GC_mark_stack_top_reg--;
- descr &= ~DS_TAGS;
+ 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) {
- PUSH_CONTENTS(current, GC_mark_stack_top_reg, mark_stack_limit,
- current_p, exit1);
+ PREFETCH((ptr_t)current);
+ HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
+ mark_stack_limit, current_p, exit1);
}
}
descr <<= 1;
++ current_p;
}
continue;
- case DS_PROC:
- GC_mark_stack_top_reg--;
- credit -= PROC_BYTES;
-#ifdef GC_DEBUG
- current_p = GC_debug_object_start(current_p);
-#endif
- GC_mark_stack_top_reg =
+ case GC_DS_PROC:
+ mark_stack_top--;
+ credit -= GC_PROC_BYTES;
+ mark_stack_top =
(*PROC(descr))
- (current_p, GC_mark_stack_top_reg,
+ (current_p, mark_stack_top,
mark_stack_limit, ENV(descr));
continue;
- case DS_PER_OBJECT:
- GC_mark_stack_top_reg -> mse_descr =
- *(word *)((ptr_t)current_p + descr - tag);
+ 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 {
- GC_mark_stack_top_reg--;
+ } 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;
- while (current_p <= limit) {
- current = *current_p;
- if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
- PUSH_CONTENTS(current, GC_mark_stack_top_reg,
- mark_stack_limit, current_p, exit2);
+ {
+# define PREF_DIST 4
+
+# ifndef SMALL_CONFIG
+ word deferred;
+
+ /* Try to prefetch the next pointer to be examined asap. */
+ /* Empirically, this also seems to help slightly without */
+ /* prefetches, at least on linux/X86. Presumably this loop */
+ /* ends up with less register pressure, and gcc thus ends up */
+ /* generating slightly better code. Overall gcc code quality */
+ /* for this loop is still not great. */
+ for(;;) {
+ PREFETCH((ptr_t)limit - PREF_DIST*CACHE_LINE_SIZE);
+ GC_ASSERT(limit >= current_p);
+ deferred = *limit;
+ FIXUP_POINTER(deferred);
+ limit = (word *)((char *)limit - ALIGNMENT);
+ if ((ptr_t)deferred >= least_ha && (ptr_t)deferred < greatest_ha) {
+ PREFETCH((ptr_t)deferred);
+ break;
+ }
+ if (current_p > limit) goto next_object;
+ /* Unroll once, so we don't do too many of the prefetches */
+ /* based on limit. */
+ deferred = *limit;
+ FIXUP_POINTER(deferred);
+ limit = (word *)((char *)limit - ALIGNMENT);
+ if ((ptr_t)deferred >= least_ha && (ptr_t)deferred < greatest_ha) {
+ PREFETCH((ptr_t)deferred);
+ break;
+ }
+ if (current_p > limit) goto next_object;
+ }
+# endif
+
+ while (current_p <= limit) {
+ /* Empirically, unrolling this loop doesn't help a lot. */
+ /* Since HC_PUSH_CONTENTS expands to a lot of code, */
+ /* we don't. */
+ current = *current_p;
+ FIXUP_POINTER(current);
+ PREFETCH((ptr_t)current_p + PREF_DIST*CACHE_LINE_SIZE);
+ if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
+ /* Prefetch the contents of the object we just pushed. It's */
+ /* likely we will need them soon. */
+ PREFETCH((ptr_t)current);
+ HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
+ mark_stack_limit, current_p, exit2);
+ }
+ current_p = (word *)((char *)current_p + ALIGNMENT);
}
- 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
}
}
- GC_mark_stack_top = GC_mark_stack_top_reg;
+ return mark_stack_top;
+}
+
+#ifdef PARALLEL_MARK
+
+/* We assume we have an ANSI C Compiler. */
+GC_bool GC_help_wanted = FALSE;
+unsigned GC_helper_count = 0;
+unsigned GC_active_count = 0;
+mse * VOLATILE GC_first_nonempty;
+word GC_mark_no = 0;
+
+#define LOCAL_MARK_STACK_SIZE HBLKSIZE
+ /* Under normal circumstances, this is big enough to guarantee */
+ /* We don't overflow half of it in a single call to */
+ /* GC_mark_from. */
+
+
+/* Steal mark stack entries starting at mse low into mark stack local */
+/* until we either steal mse high, or we have max entries. */
+/* Return a pointer to the top of the local mark stack. */
+/* *next is replaced by a pointer to the next unscanned mark stack */
+/* entry. */
+mse * GC_steal_mark_stack(mse * low, mse * high, mse * local,
+ unsigned max, mse **next)
+{
+ mse *p;
+ mse *top = local - 1;
+ unsigned i = 0;
+
+ /* Make sure that prior writes to the mark stack are visible. */
+ /* On some architectures, the fact that the reads are */
+ /* volatile should suffice. */
+# if !defined(IA64) && !defined(HP_PA) && !defined(I386)
+ GC_memory_barrier();
+# endif
+ GC_ASSERT(high >= low-1 && high - low + 1 <= GC_mark_stack_size);
+ for (p = low; p <= high && i <= max; ++p) {
+ word descr = *(volatile word *) &(p -> mse_descr);
+ /* In the IA64 memory model, the following volatile store is */
+ /* ordered after this read of descr. Thus a thread must read */
+ /* the original nonzero value. HP_PA appears to be similar, */
+ /* and if I'm reading the P4 spec correctly, X86 is probably */
+ /* also OK. In some other cases we need a barrier. */
+# if !defined(IA64) && !defined(HP_PA) && !defined(I386)
+ GC_memory_barrier();
+# endif
+ if (descr != 0) {
+ *(volatile word *) &(p -> mse_descr) = 0;
+ /* More than one thread may get this entry, but that's only */
+ /* a minor performance problem. */
+ ++top;
+ top -> mse_descr = descr;
+ top -> mse_start = p -> mse_start;
+ GC_ASSERT( (top -> mse_descr & GC_DS_TAGS) != GC_DS_LENGTH ||
+ top -> mse_descr < (ptr_t)GC_greatest_plausible_heap_addr
+ - (ptr_t)GC_least_plausible_heap_addr);
+ /* If this is a big object, count it as */
+ /* size/256 + 1 objects. */
+ ++i;
+ if ((descr & GC_DS_TAGS) == GC_DS_LENGTH) i += (descr >> 8);
+ }
+ }
+ *next = p;
+ return top;
}
+/* Copy back a local mark stack. */
+/* low and high are inclusive bounds. */
+void GC_return_mark_stack(mse * low, mse * high)
+{
+ mse * my_top;
+ mse * my_start;
+ size_t stack_size;
+
+ if (high < low) return;
+ stack_size = high - low + 1;
+ GC_acquire_mark_lock();
+ my_top = GC_mark_stack_top;
+ my_start = my_top + 1;
+ if (my_start - GC_mark_stack + stack_size > GC_mark_stack_size) {
+# ifdef CONDPRINT
+ if (GC_print_stats) {
+ GC_printf0("No room to copy back mark stack.");
+ }
+# endif
+ GC_mark_state = MS_INVALID;
+ GC_mark_stack_too_small = TRUE;
+ /* We drop the local mark stack. We'll fix things later. */
+ } else {
+ BCOPY(low, my_start, stack_size * sizeof(mse));
+ GC_ASSERT(GC_mark_stack_top = my_top);
+# if !defined(IA64) && !defined(HP_PA)
+ GC_memory_barrier();
+# endif
+ /* On IA64, the volatile write acts as a release barrier. */
+ GC_mark_stack_top = my_top + stack_size;
+ }
+ GC_release_mark_lock();
+ GC_notify_all_marker();
+}
+
+/* Mark from the local mark stack. */
+/* On return, the local mark stack is empty. */
+/* But this may be achieved by copying the */
+/* local mark stack back into the global one. */
+void GC_do_local_mark(mse *local_mark_stack, mse *local_top)
+{
+ unsigned n;
+# define N_LOCAL_ITERS 1
+
+# ifdef GC_ASSERTIONS
+ /* Make sure we don't hold mark lock. */
+ GC_acquire_mark_lock();
+ GC_release_mark_lock();
+# endif
+ for (;;) {
+ for (n = 0; n < N_LOCAL_ITERS; ++n) {
+ local_top = GC_mark_from(local_top, local_mark_stack,
+ local_mark_stack + LOCAL_MARK_STACK_SIZE);
+ if (local_top < local_mark_stack) return;
+ if (local_top - local_mark_stack >= LOCAL_MARK_STACK_SIZE/2) {
+ GC_return_mark_stack(local_mark_stack, local_top);
+ return;
+ }
+ }
+ if (GC_mark_stack_top < GC_first_nonempty &&
+ GC_active_count < GC_helper_count
+ && local_top > local_mark_stack + 1) {
+ /* Try to share the load, since the main stack is empty, */
+ /* and helper threads are waiting for a refill. */
+ /* The entries near the bottom of the stack are likely */
+ /* to require more work. Thus we return those, eventhough */
+ /* it's harder. */
+ mse * p;
+ mse * new_bottom = local_mark_stack
+ + (local_top - local_mark_stack)/2;
+ GC_ASSERT(new_bottom > local_mark_stack
+ && new_bottom < local_top);
+ GC_return_mark_stack(local_mark_stack, new_bottom - 1);
+ memmove(local_mark_stack, new_bottom,
+ (local_top - new_bottom + 1) * sizeof(mse));
+ local_top -= (new_bottom - local_mark_stack);
+ }
+ }
+}
+
+#define ENTRIES_TO_GET 5
+
+long GC_markers = 2; /* Normally changed by thread-library- */
+ /* -specific code. */
+
+/* Mark using the local mark stack until the global mark stack is empty */
+/* and there are no active workers. Update GC_first_nonempty to reflect */
+/* progress. */
+/* Caller does not hold mark lock. */
+/* Caller has already incremented GC_helper_count. We decrement it, */
+/* and maintain GC_active_count. */
+void GC_mark_local(mse *local_mark_stack, int id)
+{
+ mse * my_first_nonempty;
+
+ GC_acquire_mark_lock();
+ GC_active_count++;
+ my_first_nonempty = GC_first_nonempty;
+ GC_ASSERT(GC_first_nonempty >= GC_mark_stack &&
+ GC_first_nonempty <= GC_mark_stack_top + 1);
+# ifdef PRINTSTATS
+ GC_printf1("Starting mark helper %lu\n", (unsigned long)id);
+# endif
+ GC_release_mark_lock();
+ for (;;) {
+ size_t n_on_stack;
+ size_t n_to_get;
+ mse *next;
+ mse * my_top;
+ mse * local_top;
+ mse * global_first_nonempty = GC_first_nonempty;
+
+ GC_ASSERT(my_first_nonempty >= GC_mark_stack &&
+ my_first_nonempty <= GC_mark_stack_top + 1);
+ GC_ASSERT(global_first_nonempty >= GC_mark_stack &&
+ global_first_nonempty <= GC_mark_stack_top + 1);
+ if (my_first_nonempty < global_first_nonempty) {
+ my_first_nonempty = global_first_nonempty;
+ } else if (global_first_nonempty < my_first_nonempty) {
+ GC_compare_and_exchange((word *)(&GC_first_nonempty),
+ (word) global_first_nonempty,
+ (word) my_first_nonempty);
+ /* If this fails, we just go ahead, without updating */
+ /* GC_first_nonempty. */
+ }
+ /* Perhaps we should also update GC_first_nonempty, if it */
+ /* is less. But that would require using atomic updates. */
+ my_top = GC_mark_stack_top;
+ n_on_stack = my_top - my_first_nonempty + 1;
+ if (0 == n_on_stack) {
+ GC_acquire_mark_lock();
+ my_top = GC_mark_stack_top;
+ n_on_stack = my_top - my_first_nonempty + 1;
+ if (0 == n_on_stack) {
+ GC_active_count--;
+ GC_ASSERT(GC_active_count <= GC_helper_count);
+ /* Other markers may redeposit objects */
+ /* on the stack. */
+ if (0 == GC_active_count) GC_notify_all_marker();
+ while (GC_active_count > 0
+ && GC_first_nonempty > GC_mark_stack_top) {
+ /* We will be notified if either GC_active_count */
+ /* reaches zero, or if more objects are pushed on */
+ /* the global mark stack. */
+ GC_wait_marker();
+ }
+ if (GC_active_count == 0 &&
+ GC_first_nonempty > GC_mark_stack_top) {
+ GC_bool need_to_notify = FALSE;
+ /* The above conditions can't be falsified while we */
+ /* hold the mark lock, since neither */
+ /* GC_active_count nor GC_mark_stack_top can */
+ /* change. GC_first_nonempty can only be */
+ /* incremented asynchronously. Thus we know that */
+ /* both conditions actually held simultaneously. */
+ GC_helper_count--;
+ if (0 == GC_helper_count) need_to_notify = TRUE;
+# ifdef PRINTSTATS
+ GC_printf1(
+ "Finished mark helper %lu\n", (unsigned long)id);
+# endif
+ GC_release_mark_lock();
+ if (need_to_notify) GC_notify_all_marker();
+ return;
+ }
+ /* else there's something on the stack again, or */
+ /* another helper may push something. */
+ GC_active_count++;
+ GC_ASSERT(GC_active_count > 0);
+ GC_release_mark_lock();
+ continue;
+ } else {
+ GC_release_mark_lock();
+ }
+ }
+ n_to_get = ENTRIES_TO_GET;
+ if (n_on_stack < 2 * ENTRIES_TO_GET) n_to_get = 1;
+ local_top = GC_steal_mark_stack(my_first_nonempty, my_top,
+ local_mark_stack, n_to_get,
+ &my_first_nonempty);
+ GC_ASSERT(my_first_nonempty >= GC_mark_stack &&
+ my_first_nonempty <= GC_mark_stack_top + 1);
+ GC_do_local_mark(local_mark_stack, local_top);
+ }
+}
+
+/* Perform Parallel mark. */
+/* We hold the GC lock, not the mark lock. */
+/* Currently runs until the mark stack is */
+/* empty. */
+void GC_do_parallel_mark()
+{
+ mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
+ mse * local_top;
+ mse * my_top;
+
+ GC_acquire_mark_lock();
+ GC_ASSERT(I_HOLD_LOCK());
+ /* This could be a GC_ASSERT, but it seems safer to keep it on */
+ /* all the time, especially since it's cheap. */
+ if (GC_help_wanted || GC_active_count != 0 || GC_helper_count != 0)
+ ABORT("Tried to start parallel mark in bad state");
+# ifdef PRINTSTATS
+ GC_printf1("Starting marking for mark phase number %lu\n",
+ (unsigned long)GC_mark_no);
+# endif
+ GC_first_nonempty = GC_mark_stack;
+ GC_active_count = 0;
+ GC_helper_count = 1;
+ GC_help_wanted = TRUE;
+ GC_release_mark_lock();
+ GC_notify_all_marker();
+ /* Wake up potential helpers. */
+ GC_mark_local(local_mark_stack, 0);
+ GC_acquire_mark_lock();
+ GC_help_wanted = FALSE;
+ /* Done; clean up. */
+ while (GC_helper_count > 0) GC_wait_marker();
+ /* GC_helper_count cannot be incremented while GC_help_wanted == FALSE */
+# ifdef PRINTSTATS
+ GC_printf1(
+ "Finished marking for mark phase number %lu\n",
+ (unsigned long)GC_mark_no);
+# endif
+ GC_mark_no++;
+ GC_release_mark_lock();
+ GC_notify_all_marker();
+}
+
+
+/* Try to help out the marker, if it's running. */
+/* We do not hold the GC lock, but the requestor does. */
+void GC_help_marker(word my_mark_no)
+{
+ mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
+ unsigned my_id;
+ mse * my_first_nonempty;
+
+ if (!GC_parallel) return;
+ GC_acquire_mark_lock();
+ while (GC_mark_no < my_mark_no
+ || !GC_help_wanted && GC_mark_no == my_mark_no) {
+ GC_wait_marker();
+ }
+ my_id = GC_helper_count;
+ if (GC_mark_no != my_mark_no || my_id >= GC_markers) {
+ /* Second test is useful only if original threads can also */
+ /* act as helpers. Under Linux they can't. */
+ GC_release_mark_lock();
+ return;
+ }
+ GC_helper_count = my_id + 1;
+ GC_release_mark_lock();
+ GC_mark_local(local_mark_stack, my_id);
+ /* GC_mark_local decrements GC_helper_count. */
+}
+
+#endif /* PARALLEL_MARK */
+
/* Allocate or reallocate space for mark stack of size s words */
/* May silently fail. */
static void alloc_mark_stack(n)
word n;
{
- mse * new_stack = (mse *)GC_scratch_alloc(n * sizeof(struct ms_entry));
+ 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);
- word size = GC_mark_stack_size * sizeof(struct ms_entry);
+ 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);
- GC_add_to_heap((struct hblk *)
- ((word)GC_mark_stack + displ), size);
+ 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;
-# ifdef PRINTSTATS
+ 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 PRINTSTATS
+# ifdef CONDPRINT
+ if (GC_print_stats) {
GC_printf1("Failed to grow mark stack to %lu frames\n",
(unsigned long) n);
+ }
# endif
}
} else {
}
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;
}
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 + GC_mark_stack_size) {
+ if (GC_mark_stack_top >= GC_mark_stack_limit) {
ABORT("unexpected mark stack overflow");
}
length = top - bottom;
-# if DS_TAGS > ALIGNMENT - 1
- length += DS_TAGS;
- length &= ~DS_TAGS;
+# 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 that may have been
- * dirtied. A block h is assumed dirty if dirty_fn(h) != 0.
+ * 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_dirty(bottom, top, dirty_fn, push_fn)
+void GC_push_selected(bottom, top, dirty_fn, push_fn)
ptr_t bottom;
ptr_t top;
-int (*dirty_fn)(/* struct hblk * h */);
-void (*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;
(*push_fn)((ptr_t)h, top);
}
}
- if (GC_mark_stack_top >= GC_mark_stack + GC_mark_stack_size) {
+ 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;
if (GC_dirty_maintained) {
# ifdef PROC_VDB
/* Pages that were never dirtied cannot contain pointers */
- GC_push_dirty(bottom, top, GC_page_was_ever_dirty, GC_push_all);
+ GC_push_selected(bottom, top, GC_page_was_ever_dirty, GC_push_all);
# else
GC_push_all(bottom, top);
# endif
GC_push_all(bottom, top);
}
} else {
- GC_push_dirty(bottom, top, GC_page_was_dirty, GC_push_all);
+ GC_push_selected(bottom, top, GC_page_was_dirty, GC_push_all);
}
}
#endif
-# ifdef MSWIN32
+# 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);
+ 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((char *)(p))
# endif
-/* As above, but argument passed preliminary test. */
-# ifdef PRINT_BLACK_LIST
- void GC_push_one_checked(p, interior_ptrs, source)
+/* 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_push_one_checked(p, interior_ptrs)
+ void GC_mark_and_push_stack(p)
# define source 0
# endif
register word p;
-register GC_bool interior_ptrs;
{
register word r;
register hdr * hhdr;
GET_HDR(p, hhdr);
if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
- if (hhdr != 0 && interior_ptrs) {
+ if (hhdr != 0) {
r = BASE(p);
hhdr = HDR(r);
displ = BYTES_TO_WORDS(HBLKDISPL(r));
- } else {
- hhdr = 0;
}
} else {
register map_entry_type map_entry;
displ = HBLKDISPL(p);
map_entry = MAP_ENTRY((hhdr -> hb_map), displ);
- if (map_entry == OBJ_INVALID) {
- if (interior_ptrs) {
- r = BASE(p);
- displ = BYTES_TO_WORDS(HBLKDISPL(r));
- if (r == 0) hhdr = 0;
+ 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 {
- hhdr = 0;
+ /* Offset invalid, but map reflects interior pointers */
+ hhdr = 0;
}
} else {
displ = BYTES_TO_WORDS(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) {
- if (interior_ptrs) {
-# ifdef PRINT_BLACK_LIST
- GC_add_to_black_list_stack(p, source);
-# else
- GC_add_to_black_list_stack(p);
-# endif
- } else {
- GC_ADD_TO_BLACK_LIST_NORMAL(p, source);
-# undef source /* In case we had to define it. */
- }
+# 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[GC_mark_stack_size]));
+ GC_mark_stack_limit);
}
}
}
/*
* 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_stack(bottom, top)
+void GC_push_all_eager(bottom, top)
ptr_t bottom;
ptr_t top;
{
-# ifdef ALL_INTERIOR_POINTERS
- GC_push_all(bottom, top);
-# ifdef TRACE_BUF
- GC_add_trace_entry("GC_push_all_stack", bottom, top);
-# endif
-# else
- word * b = (word *)(((long) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
- word * t = (word *)(((long) top) & ~(ALIGNMENT-1));
+ word * b = (word *)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
+ word * t = (word *)(((word) top) & ~(ALIGNMENT-1));
register word *p;
register word q;
register word *lim;
# 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. */
+ /* 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);
+ 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 */
-#ifndef SMALL_CONFIG
+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[divWORDSZ(HDR_WORDS)]);
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
register word *p;
word *plim;
register int i;
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
while(mark_word != 0) {
if (mark_word & 1) {
q = p[i];
- GC_PUSH_ONE_HEAP(q);
+ GC_PUSH_ONE_HEAP(q, p + i);
}
i++;
mark_word >>= 1;
}
# 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;
}
struct hblk *h;
register hdr * hhdr;
{
- word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
register word *p;
word *plim;
register int i;
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
while(mark_word != 0) {
if (mark_word & 1) {
q = p[i];
- GC_PUSH_ONE_HEAP(q);
+ GC_PUSH_ONE_HEAP(q, p + i);
q = p[i+1];
- GC_PUSH_ONE_HEAP(q);
+ GC_PUSH_ONE_HEAP(q, p + i);
}
i += 2;
mark_word >>= 2;
}
# 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 */
struct hblk *h;
register hdr * hhdr;
{
- word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
register word *p;
word *plim;
register int i;
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
while(mark_word != 0) {
if (mark_word & 1) {
q = p[i];
- GC_PUSH_ONE_HEAP(q);
+ GC_PUSH_ONE_HEAP(q, p + i);
q = p[i+1];
- GC_PUSH_ONE_HEAP(q);
+ GC_PUSH_ONE_HEAP(q, p + i + 1);
q = p[i+2];
- GC_PUSH_ONE_HEAP(q);
+ GC_PUSH_ONE_HEAP(q, p + i + 2);
q = p[i+3];
- GC_PUSH_ONE_HEAP(q);
+ GC_PUSH_ONE_HEAP(q, p + i + 3);
}
i += 4;
mark_word >>= 4;
}
# 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 */
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[GC_mark_stack_size]);
+ register mse * mark_stack_limit = GC_mark_stack_limit;
/* Some quick shortcuts: */
- {
- struct obj_kind *ok = &(GC_obj_kinds[hhdr -> hb_obj_kind]);
- if ((0 | DS_LENGTH) == ok -> ok_descriptor
- && FALSE == ok -> ok_relocate_descr)
- return;
- }
+ if ((0 | GC_DS_LENGTH) == descr) return;
if (GC_block_empty(hhdr)/* nothing marked */) return;
-# ifdef GATHERSTATS
- GC_n_rescuing_pages++;
-# endif
+ GC_n_rescuing_pages++;
GC_objects_are_marked = TRUE;
if (sz > MAXOBJSZ) {
- lim = (word *)(h + 1);
+ lim = (word *)h;
} else {
lim = (word *)(h + 1) - sz;
}
switch(sz) {
-# if !defined(SMALL_CONFIG)
+# if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
case 1:
GC_push_marked1(h, hhdr);
break;
# endif
-# if !defined(SMALL_CONFIG) && !defined(UNALIGNED)
+# if !defined(SMALL_CONFIG) && !defined(UNALIGNED) && \
+ !defined(USE_MARK_BYTES)
case 2:
GC_push_marked2(h, hhdr);
break;
# endif
default:
GC_mark_stack_top_reg = GC_mark_stack_top;
- for (p = (word *)h + HDR_WORDS, word_no = HDR_WORDS; p <= lim;
- p += sz, word_no += sz) {
- /* This ignores user specified mark procs. This currently */
- /* doesn't matter, since marking from the whole object */
- /* is always sufficient, and we will eventually use the user */
- /* mark proc to avoid any bogus pointers. */
+ 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);
{
register int sz = hhdr -> hb_sz;
- if (sz < MAXOBJSZ) {
+ if (sz <= MAXOBJSZ) {
return(GC_page_was_dirty(h));
} else {
register ptr_t p = (ptr_t)h;
- sz += HDR_WORDS;
sz = WORDS_TO_BYTES(sz);
while (p < (ptr_t)h + sz) {
if (GC_page_was_dirty((struct hblk *)p)) return(TRUE);
{
register hdr * hhdr;
- h = GC_next_block(h);
+ h = GC_next_used_block(h);
if (h == 0) return(0);
hhdr = HDR(h);
GC_push_marked(h, hhdr);
struct hblk * GC_push_next_marked_dirty(h)
struct hblk *h;
{
- register hdr * hhdr = HDR(h);
+ register hdr * hhdr;
if (!GC_dirty_maintained) { ABORT("dirty bits not set up"); }
for (;;) {
- h = GC_next_block(h);
+ h = GC_next_used_block(h);
if (h == 0) return(0);
hhdr = HDR(h);
# ifdef STUBBORN_ALLOC
register hdr * hhdr = HDR(h);
for (;;) {
- h = GC_next_block(h);
+ h = GC_next_used_block(h);
if (h == 0) return(0);
hhdr = HDR(h);
if (hhdr -> hb_obj_kind == UNCOLLECTABLE) break;
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