--- /dev/null
+/*
+ * 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 "private/gc_pmark.h"
+
+#include <stdio.h>
+
+#if defined(MSWIN32) && defined(__GNUC__)
+# include <excpt.h>
+#endif
+
+/* We put this here to minimize the risk of inlining. */
+/*VARARGS*/
+#if defined(__BORLANDC__) || defined(__WATCOMC__) || defined(__CC_ARM)
+ /*ARGSUSED*/
+ void GC_noop(void *p, ...) {}
+#else
+# ifdef __DMC__
+ void GC_noop(...) {}
+# else
+ void GC_noop() {}
+# endif
+#endif
+
+/* Single argument version, robust against whole program analysis. */
+volatile word GC_noop_sink;
+GC_API void GC_CALL GC_noop1(word x)
+{
+ GC_noop_sink = x;
+}
+
+/* mark_proc GC_mark_procs[MAX_MARK_PROCS] = {0} -- declared in gc_priv.h */
+
+GC_INNER unsigned 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. */
+GC_INNER 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 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*/ { (void **)&GC_sobjfreelist[0], 0,
+ 0 | GC_DS_LENGTH, TRUE /* add length to descr */, TRUE },
+# endif
+};
+
+# ifdef ATOMIC_UNCOLLECTABLE
+# ifdef STUBBORN_ALLOC
+# define GC_N_KINDS_INITIAL_VALUE 5
+# else
+# define GC_N_KINDS_INITIAL_VALUE 4
+# endif
+# else
+# ifdef STUBBORN_ALLOC
+# define GC_N_KINDS_INITIAL_VALUE 4
+# else
+# define GC_N_KINDS_INITIAL_VALUE 3
+# endif
+# endif
+
+GC_INNER unsigned GC_n_kinds = GC_N_KINDS_INITIAL_VALUE;
+
+# 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.
+ */
+
+STATIC word GC_n_rescuing_pages = 0;
+ /* Number of dirty pages we marked from */
+ /* excludes ptrfree pages, etc. */
+
+GC_INNER mse * GC_mark_stack = NULL;
+GC_INNER mse * GC_mark_stack_limit = NULL;
+GC_INNER size_t GC_mark_stack_size = 0;
+
+#ifdef PARALLEL_MARK
+ GC_INNER mse * volatile GC_mark_stack_top = NULL;
+ /* Updated only with mark lock held, but read asynchronously. */
+ STATIC volatile AO_t GC_first_nonempty = 0;
+ /* Lowest entry on mark stack */
+ /* that may be nonempty. */
+ /* Updated only by initiating */
+ /* thread. */
+#else
+ GC_INNER mse * GC_mark_stack_top = NULL;
+#endif
+
+GC_INNER mark_state_t GC_mark_state = MS_NONE;
+
+GC_INNER GC_bool GC_mark_stack_too_small = FALSE;
+
+static struct hblk * scan_ptr;
+
+STATIC 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_INNER GC_bool GC_collection_in_progress(void)
+{
+ return(GC_mark_state != MS_NONE);
+}
+
+/* clear all mark bits in the header */
+GC_INNER void GC_clear_hdr_marks(hdr *hhdr)
+{
+ size_t last_bit = FINAL_MARK_BIT(hhdr -> hb_sz);
+ BZERO(hhdr -> hb_marks, sizeof(hhdr->hb_marks));
+ set_mark_bit_from_hdr(hhdr, last_bit);
+ hhdr -> hb_n_marks = 0;
+}
+
+/* Set all mark bits in the header. Used for uncollectable blocks. */
+GC_INNER void GC_set_hdr_marks(hdr *hhdr)
+{
+ unsigned i;
+ size_t sz = hhdr -> hb_sz;
+ unsigned n_marks = (unsigned)FINAL_MARK_BIT(sz);
+
+# ifdef USE_MARK_BYTES
+ for (i = 0; i <= n_marks; i += (unsigned)MARK_BIT_OFFSET(sz)) {
+ hhdr -> hb_marks[i] = 1;
+ }
+# else
+ for (i = 0; i < divWORDSZ(n_marks + WORDSZ); ++i) {
+ hhdr -> hb_marks[i] = ONES;
+ }
+# endif
+# ifdef MARK_BIT_PER_OBJ
+ hhdr -> hb_n_marks = n_marks - 1;
+# else
+ hhdr -> hb_n_marks = HBLK_OBJS(sz);
+# endif
+}
+
+/*
+ * Clear all mark bits associated with block h.
+ */
+/*ARGSUSED*/
+static void clear_marks_for_block(struct hblk *h, word dummy)
+{
+ 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(ptr_t p)
+{
+ struct hblk *h = HBLKPTR(p);
+ hdr * hhdr = HDR(h);
+ word bit_no = MARK_BIT_NO(p - (ptr_t)h, hhdr -> hb_sz);
+
+ if (!mark_bit_from_hdr(hhdr, bit_no)) {
+ set_mark_bit_from_hdr(hhdr, bit_no);
+ ++hhdr -> hb_n_marks;
+ }
+}
+
+void GC_clear_mark_bit(ptr_t p)
+{
+ struct hblk *h = HBLKPTR(p);
+ hdr * hhdr = HDR(h);
+ word bit_no = MARK_BIT_NO(p - (ptr_t)h, hhdr -> hb_sz);
+
+ if (mark_bit_from_hdr(hhdr, bit_no)) {
+ size_t n_marks;
+ clear_mark_bit_from_hdr(hhdr, bit_no);
+ n_marks = hhdr -> hb_n_marks - 1;
+# ifdef PARALLEL_MARK
+ if (n_marks != 0 || !GC_parallel)
+ hhdr -> hb_n_marks = n_marks;
+ /* Don't decrement to zero. The counts are approximate due to */
+ /* concurrency issues, but we need to ensure that a count of */
+ /* zero implies an empty block. */
+# else
+ hhdr -> hb_n_marks = n_marks;
+# endif
+ }
+}
+
+GC_bool GC_is_marked(ptr_t p)
+{
+ struct hblk *h = HBLKPTR(p);
+ hdr * hhdr = HDR(h);
+ word bit_no = MARK_BIT_NO(p - (ptr_t)h, hhdr -> hb_sz);
+
+ return((GC_bool)mark_bit_from_hdr(hhdr, bit_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.)
+ */
+GC_INNER void GC_clear_marks(void)
+{
+ 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 CHECKSUMS
+ void GC_check_dirty(void);
+#endif
+
+/* Initiate a garbage collection. Initiates a full collection if the */
+/* mark state is invalid. */
+GC_INNER void GC_initiate_gc(void)
+{
+# ifndef GC_DISABLE_INCREMENTAL
+ if (GC_dirty_maintained) GC_read_dirty();
+# endif
+# ifdef STUBBORN_ALLOC
+ GC_read_changed();
+# endif
+# ifdef CHECKSUMS
+ 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;
+}
+
+#ifdef PARALLEL_MARK
+ STATIC void GC_do_parallel_mark(void); /* initiate parallel marking. */
+#endif /* PARALLEL_MARK */
+
+#ifdef GC_DISABLE_INCREMENTAL
+# define GC_push_next_marked_dirty(h) GC_push_next_marked(h)
+#else
+ STATIC struct hblk * GC_push_next_marked_dirty(struct hblk *h);
+ /* Invoke GC_push_marked on next dirty block above h. */
+ /* Return a pointer just past the end of this block. */
+#endif /* !GC_DISABLE_INCREMENTAL */
+STATIC struct hblk * GC_push_next_marked(struct hblk *h);
+ /* Ditto, but also mark from clean pages. */
+STATIC struct hblk * GC_push_next_marked_uncollectable(struct hblk *h);
+ /* Ditto, but mark only from uncollectable pages. */
+
+static void alloc_mark_stack(size_t);
+
+# if (defined(MSWIN32) || defined(MSWINCE)) && !defined(__GNUC__) \
+ || defined(MSWIN32) && defined(I386) /* for Win98 */ \
+ || defined(USE_PROC_FOR_LIBRARIES) && defined(THREADS)
+ /* Under rare conditions, we may end up marking from nonexistent memory. */
+ /* Hence we need to be prepared to recover by running GC_mark_some */
+ /* with a suitable handler in place. */
+ /* FIXME: Should we really need it for WinCE? If yes then */
+ /* WRAP_MARK_SOME should be also defined for CeGCC which requires */
+ /* CPU/OS-specific code in mark_ex_handler() and GC_mark_some() */
+ /* (for manual stack unwinding and exception handler installation). */
+# define WRAP_MARK_SOME
+# endif
+
+/* 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 WRAP_MARK_SOME
+ /* 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. */
+ STATIC GC_bool GC_mark_some_inner(ptr_t cold_gc_frame)
+#else
+ GC_INNER GC_bool GC_mark_some(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) {
+ if (GC_print_stats) {
+ GC_log_printf("Marked from %lu dirty pages\n",
+ (unsigned long)GC_n_rescuing_pages);
+ }
+ 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 < (mse *)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 WRAP_MARK_SOME
+
+# if (defined(MSWIN32) || defined(MSWINCE)) && defined(__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__ && MSWIN32 */
+
+#if defined(GC_WIN32_THREADS) && !defined(__GNUC__)
+ GC_bool GC_started_thread_while_stopped(void);
+ /* In win32_threads.c. Did we invalidate mark phase with an */
+ /* unexpected thread start? */
+#endif
+
+ GC_INNER GC_bool GC_mark_some(ptr_t cold_gc_frame)
+ {
+ GC_bool ret_val;
+
+# if defined(MSWIN32) || defined(MSWINCE)
+# ifndef __GNUC__
+ /* Windows 98 appears to asynchronously create and remove */
+ /* writable memory mappings, for reasons we haven't yet */
+ /* understood. Since we look for writable regions to */
+ /* determine the root set, we may try to mark from an */
+ /* address range that disappeared since we started the */
+ /* collection. Thus we have to recover from faults here. */
+ /* This code does not appear to be necessary for Windows */
+ /* 95/NT/2000+. Note that this code should never generate */
+ /* an incremental GC write fault. */
+ /* This code seems to be necessary for WinCE (at least in */
+ /* the case we'd decide to add MEM_PRIVATE sections to */
+ /* data roots in GC_register_dynamic_libraries()). */
+ /* It's conceivable that this is the same issue with */
+ /* terminating threads that we see with Linux and */
+ /* USE_PROC_FOR_LIBRARIES. */
+
+ __try {
+ ret_val = GC_mark_some_inner(cold_gc_frame);
+ } __except (GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ?
+ EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
+ goto handle_ex;
+ }
+# ifdef GC_WIN32_THREADS
+ /* With DllMain-based thread tracking, a thread may have */
+ /* started while we were marking. This is logically equivalent */
+ /* to the exception case; our results are invalid and we have */
+ /* to start over. This cannot be prevented since we can't */
+ /* block in DllMain. */
+ if (GC_started_thread_while_stopped()) goto handle_ex;
+# endif
+ rm_handler:
+ return ret_val;
+
+# else /* __GNUC__ */
+
+ /* Manually install an exception handler since GCC does */
+ /* not yet support Structured Exception Handling (SEH) on */
+ /* Win32. */
+
+ ext_ex_regn er;
+
+ 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));
+ ret_val = GC_mark_some_inner(cold_gc_frame);
+ /* Prevent GCC from considering the following code unreachable */
+ /* and thus eliminating it. */
+ if (er.alt_path == 0)
+ goto handle_ex;
+ rm_handler:
+ /* Uninstall the exception handler */
+ __asm__ __volatile__ ("mov %0, %%fs:0" : : "r" (er.ex_reg.prev));
+ return ret_val;
+
+# endif /* __GNUC__ */
+# else /* !MSWIN32 */
+ /* Here we are handling the case in which /proc is used for root */
+ /* finding, and we have threads. We may find a stack for a */
+ /* thread that is in the process of exiting, and disappears */
+ /* while we are marking it. This seems extremely difficult to */
+ /* avoid otherwise. */
+ if (GC_incremental) {
+ WARN("Incremental GC incompatible with /proc roots\n", 0);
+ /* I'm not sure if this could still work ... */
+ }
+ GC_setup_temporary_fault_handler();
+ if(SETJMP(GC_jmp_buf) != 0) goto handle_ex;
+ ret_val = GC_mark_some_inner(cold_gc_frame);
+ rm_handler:
+ GC_reset_fault_handler();
+ return ret_val;
+
+# endif /* !MSWIN32 */
+
+handle_ex:
+ /* Exception handler starts here for all cases. */
+ if (GC_print_stats) {
+ GC_log_printf(
+ "Caught ACCESS_VIOLATION in marker; memory mapping disappeared\n");
+ }
+
+ /* 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;
+ goto rm_handler; /* Back to platform-specific code. */
+ }
+#endif /* WRAP_MARK_SOME */
+
+GC_INNER GC_bool GC_mark_stack_empty(void)
+{
+ return(GC_mark_stack_top < GC_mark_stack);
+}
+
+GC_INNER void GC_invalidate_mark_state(void)
+{
+ GC_mark_state = MS_INVALID;
+ GC_mark_stack_top = GC_mark_stack-1;
+}
+
+GC_INNER mse * GC_signal_mark_stack_overflow(mse *msp)
+{
+ GC_mark_state = MS_INVALID;
+ GC_mark_stack_too_small = TRUE;
+ if (GC_print_stats) {
+ GC_log_printf("Mark stack overflow; current size = %lu entries\n",
+ (unsigned long)GC_mark_stack_size);
+ }
+ return(msp - GC_MARK_STACK_DISCARDS);
+}
+
+/*
+ * Mark objects pointed to by the regions described by
+ * mark stack entries between mark_stack and mark_stack_top,
+ * inclusive. Assumes the upper limit of a mark stack entry
+ * is never 0. A mark stack entry never has size 0.
+ * We try to traverse on the order of a hblk of memory before we return.
+ * Caller is responsible for calling this until the mark stack is empty.
+ * Note that this is the most performance critical routine in the
+ * collector. Hence it contains all sorts of ugly hacks to speed
+ * things up. In particular, we avoid procedure calls on the common
+ * path, we take advantage of peculiarities of the mark descriptor
+ * encoding, we optionally maintain a cache for the block address to
+ * header mapping, we prefetch when an object is "grayed", etc.
+ */
+GC_INNER mse * GC_mark_from(mse *mark_stack_top, mse *mark_stack,
+ mse *mark_stack_limit)
+{
+ signed_word credit = HBLKSIZE; /* Remaining credit for marking work */
+ ptr_t current_p; /* Pointer to current candidate ptr. */
+ word current; /* Candidate pointer. */
+ ptr_t limit; /* (Incl) limit of current candidate */
+ /* range */
+ word descr;
+ ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
+ 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 ENABLE_TRACE
+ if (GC_trace_addr >= current_p
+ && GC_trace_addr < current_p + descr) {
+ GC_log_printf("GC:%u Large section; start %p len %lu\n",
+ (unsigned)GC_gc_no, current_p, (unsigned long)descr);
+ }
+# endif /* ENABLE_TRACE */
+# 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++;
+# ifdef ENABLE_TRACE
+ if (GC_trace_addr >= current_p
+ && GC_trace_addr < current_p + descr) {
+ GC_log_printf("GC:%u Splitting (parallel) %p at %p\n",
+ (unsigned)GC_gc_no, current_p, current_p + new_size);
+ }
+# endif /* ENABLE_TRACE */
+ current_p += new_size;
+ descr -= new_size;
+ goto retry;
+ }
+# endif /* PARALLEL_MARK */
+ mark_stack_top -> mse_start =
+ limit = current_p + WORDS_TO_BYTES(SPLIT_RANGE_WORDS-1);
+ mark_stack_top -> mse_descr =
+ descr - WORDS_TO_BYTES(SPLIT_RANGE_WORDS-1);
+# ifdef ENABLE_TRACE
+ if (GC_trace_addr >= current_p
+ && GC_trace_addr < current_p + descr) {
+ GC_log_printf("GC:%u Splitting %p at %p\n",
+ (unsigned)GC_gc_no, current_p, limit);
+ }
+# endif /* ENABLE_TRACE */
+ /* Make sure that pointers overlapping the two ranges are */
+ /* considered. */
+ limit += sizeof(word) - ALIGNMENT;
+ break;
+ case GC_DS_BITMAP:
+ mark_stack_top--;
+# ifdef ENABLE_TRACE
+ if (GC_trace_addr >= current_p
+ && GC_trace_addr < current_p + WORDS_TO_BYTES(WORDSZ-2)) {
+ GC_log_printf("GC:%u Tracing from %p bitmap descr %lu\n",
+ (unsigned)GC_gc_no, current_p, (unsigned long)descr);
+ }
+# endif /* ENABLE_TRACE */
+ descr &= ~GC_DS_TAGS;
+ credit -= WORDS_TO_BYTES(WORDSZ/2); /* guess */
+ while (descr != 0) {
+ if ((signed_word)descr < 0) {
+ current = *(word *)current_p;
+ FIXUP_POINTER(current);
+ if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
+ PREFETCH((ptr_t)current);
+# ifdef ENABLE_TRACE
+ if (GC_trace_addr == current_p) {
+ GC_log_printf("GC:%u Considering(3) %p -> %p\n",
+ (unsigned)GC_gc_no, current_p, (ptr_t)current);
+ }
+# endif /* ENABLE_TRACE */
+ PUSH_CONTENTS((ptr_t)current, mark_stack_top,
+ mark_stack_limit, current_p, exit1);
+ }
+ }
+ descr <<= 1;
+ current_p += sizeof(word);
+ }
+ continue;
+ case GC_DS_PROC:
+ mark_stack_top--;
+# ifdef ENABLE_TRACE
+ if (GC_trace_addr >= current_p
+ && GC_base(current_p) != 0
+ && GC_base(current_p) == GC_base(GC_trace_addr)) {
+ GC_log_printf("GC:%u Tracing from %p proc descr %lu\n",
+ (unsigned)GC_gc_no, current_p, (unsigned long)descr);
+ }
+# endif /* ENABLE_TRACE */
+ credit -= GC_PROC_BYTES;
+ mark_stack_top =
+ (*PROC(descr))
+ ((word *)current_p, mark_stack_top,
+ mark_stack_limit, ENV(descr));
+ continue;
+ case GC_DS_PER_OBJECT:
+ if ((signed_word)descr >= 0) {
+ /* Descriptor is in the object. */
+ descr = *(word *)(current_p + descr - GC_DS_PER_OBJECT);
+ } else {
+ /* Descriptor is in type descriptor pointed to by first */
+ /* word in object. */
+ ptr_t type_descr = *(ptr_t *)current_p;
+ /* type_descr is either a valid pointer to the descriptor */
+ /* structure, or this object was on a free list. If it */
+ /* 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_INDIR_PER_OBJ_BIAS
+ - GC_DS_PER_OBJECT)));
+ }
+ if (0 == descr) {
+ /* Can happen either because we generated a 0 descriptor */
+ /* or we saw a pointer to a free object. */
+ mark_stack_top--;
+ continue;
+ }
+ goto retry;
+ default:
+ /* Can't happen. */
+ limit = 0; /* initialized to prevent warning. */
+ }
+ } else /* Small object with length descriptor */ {
+ mark_stack_top--;
+ limit = current_p + (word)descr;
+ }
+# ifdef ENABLE_TRACE
+ if (GC_trace_addr >= current_p
+ && GC_trace_addr < limit) {
+ GC_log_printf("GC:%u Tracing from %p len %lu\n",
+ (int)GC_gc_no, current_p, (unsigned long)descr);
+ }
+# endif /* ENABLE_TRACE */
+ /* The simple case in which we're scanning a range. */
+ GC_ASSERT(!((word)current_p & (ALIGNMENT-1)));
+ credit -= limit - current_p;
+ limit -= sizeof(word);
+ {
+# define PREF_DIST 4
+
+# ifndef SMALL_CONFIG
+ word deferred;
+
+ /* Try to prefetch the next pointer to be examined asap. */
+ /* Empirically, this also seems to help slightly without */
+ /* prefetches, at least on linux/X86. Presumably this loop */
+ /* ends up with less register pressure, and gcc thus ends up */
+ /* generating slightly better code. Overall gcc code quality */
+ /* for this loop is still not great. */
+ for(;;) {
+ PREFETCH(limit - PREF_DIST*CACHE_LINE_SIZE);
+ GC_ASSERT(limit >= current_p);
+ deferred = *(word *)limit;
+ FIXUP_POINTER(deferred);
+ 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 = *(word *)limit;
+ FIXUP_POINTER(deferred);
+ 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 PUSH_CONTENTS expands to a lot of code, */
+ /* we don't. */
+ current = *(word *)current_p;
+ FIXUP_POINTER(current);
+ PREFETCH(current_p + PREF_DIST*CACHE_LINE_SIZE);
+ if ((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);
+# ifdef ENABLE_TRACE
+ if (GC_trace_addr == current_p) {
+ GC_log_printf("GC:%u Considering(1) %p -> %p\n",
+ (unsigned)GC_gc_no, current_p, (ptr_t)current);
+ }
+# endif /* ENABLE_TRACE */
+ PUSH_CONTENTS((ptr_t)current, mark_stack_top,
+ mark_stack_limit, current_p, exit2);
+ }
+ current_p += ALIGNMENT;
+ }
+
+# ifndef SMALL_CONFIG
+ /* We still need to mark the entry we previously prefetched. */
+ /* We already know that it passes the preliminary pointer */
+ /* validity test. */
+# ifdef ENABLE_TRACE
+ if (GC_trace_addr == current_p) {
+ GC_log_printf("GC:%u Considering(2) %p -> %p\n",
+ (unsigned)GC_gc_no, current_p, (ptr_t)deferred);
+ }
+# endif /* ENABLE_TRACE */
+ PUSH_CONTENTS((ptr_t)deferred, mark_stack_top,
+ mark_stack_limit, current_p, exit4);
+ next_object:;
+# endif
+ }
+ }
+ return mark_stack_top;
+}
+
+#ifdef PARALLEL_MARK
+
+STATIC GC_bool GC_help_wanted = FALSE; /* Protected by mark lock */
+STATIC unsigned GC_helper_count = 0; /* Number of running helpers. */
+ /* Protected by mark lock */
+STATIC unsigned GC_active_count = 0; /* Number of active helpers. */
+ /* Protected by mark lock */
+ /* May increase and decrease */
+ /* within each mark cycle. But */
+ /* once it returns to 0, it */
+ /* stays zero for the cycle. */
+
+GC_INNER word GC_mark_no = 0;
+
+#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. */
+STATIC mse * GC_steal_mark_stack(mse * low, mse * high, mse * local,
+ unsigned max, mse **next)
+{
+ mse *p;
+ mse *top = local - 1;
+ unsigned i = 0;
+
+ GC_ASSERT(high >= low-1 && (word)(high - low + 1) <= GC_mark_stack_size);
+ for (p = low; p <= high && i <= max; ++p) {
+ word descr = AO_load((volatile AO_t *) &(p -> mse_descr));
+ if (descr != 0) {
+ /* Must be ordered after read of descr: */
+ AO_store_release_write((volatile AO_t *) &(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 < (word)GC_greatest_plausible_heap_addr
+ - (word)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 += (int)(descr >> 8);
+ }
+ }
+ *next = p;
+ return top;
+}
+
+/* Copy back a local mark stack. */
+/* low and high are inclusive bounds. */
+STATIC void GC_return_mark_stack(mse * low, mse * high)
+{
+ mse * my_top;
+ mse * my_start;
+ size_t stack_size;
+
+ if (high < low) return;
+ stack_size = high - low + 1;
+ GC_acquire_mark_lock();
+ my_top = GC_mark_stack_top; /* Concurrent modification impossible. */
+ my_start = my_top + 1;
+ if (my_start - GC_mark_stack + stack_size > GC_mark_stack_size) {
+ if (GC_print_stats) {
+ GC_log_printf("No room to copy back mark stack\n");
+ }
+ GC_mark_state = MS_INVALID;
+ GC_mark_stack_too_small = TRUE;
+ /* We drop the local mark stack. We'll fix things later. */
+ } else {
+ BCOPY(low, my_start, stack_size * sizeof(mse));
+ GC_ASSERT((mse *)AO_load((volatile AO_t *)(&GC_mark_stack_top))
+ == my_top);
+ AO_store_release_write((volatile AO_t *)(&GC_mark_stack_top),
+ (AO_t)(my_top + stack_size));
+ /* Ensures visibility of previously written stack contents. */
+ }
+ GC_release_mark_lock();
+ GC_notify_all_marker();
+}
+
+/* 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. */
+STATIC 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 ((word)(local_top - local_mark_stack)
+ >= LOCAL_MARK_STACK_SIZE / 2) {
+ GC_return_mark_stack(local_mark_stack, local_top);
+ return;
+ }
+ }
+ if ((mse *)AO_load((volatile AO_t *)(&GC_mark_stack_top))
+ < (mse *)AO_load(&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 * 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
+
+GC_INNER 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. */
+STATIC void GC_mark_local(mse *local_mark_stack, int id)
+{
+ mse * my_first_nonempty;
+
+ GC_acquire_mark_lock();
+ GC_active_count++;
+ my_first_nonempty = (mse *)AO_load(&GC_first_nonempty);
+ GC_ASSERT((mse *)AO_load(&GC_first_nonempty) >= GC_mark_stack &&
+ (mse *)AO_load(&GC_first_nonempty) <=
+ (mse *)AO_load((volatile AO_t *)(&GC_mark_stack_top)) + 1);
+ if (GC_print_stats == VERBOSE)
+ GC_log_printf("Starting mark helper %lu\n", (unsigned long)id);
+ GC_release_mark_lock();
+ for (;;) {
+ size_t n_on_stack;
+ unsigned n_to_get;
+ mse * my_top;
+ mse * local_top;
+ mse * global_first_nonempty = (mse *)AO_load(&GC_first_nonempty);
+
+ GC_ASSERT(my_first_nonempty >= GC_mark_stack &&
+ my_first_nonempty <=
+ (mse *)AO_load((volatile AO_t *)(&GC_mark_stack_top)) + 1);
+ GC_ASSERT(global_first_nonempty >= GC_mark_stack &&
+ global_first_nonempty <=
+ (mse *)AO_load((volatile AO_t *)(&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) {
+ AO_compare_and_swap(&GC_first_nonempty,
+ (AO_t) global_first_nonempty,
+ (AO_t) my_first_nonempty);
+ /* If this fails, we just go ahead, without updating */
+ /* GC_first_nonempty. */
+ }
+ /* Perhaps we should also update GC_first_nonempty, if it */
+ /* is less. But that would require using atomic updates. */
+ my_top = (mse *)AO_load_acquire((volatile AO_t *)(&GC_mark_stack_top));
+ n_on_stack = my_top - my_first_nonempty + 1;
+ if (0 == n_on_stack) {
+ GC_acquire_mark_lock();
+ my_top = GC_mark_stack_top;
+ /* Asynchronous modification impossible here, */
+ /* since we hold mark lock. */
+ n_on_stack = my_top - my_first_nonempty + 1;
+ if (0 == n_on_stack) {
+ GC_active_count--;
+ GC_ASSERT(GC_active_count <= GC_helper_count);
+ /* Other markers may redeposit objects */
+ /* on the stack. */
+ if (0 == GC_active_count) GC_notify_all_marker();
+ while (GC_active_count > 0
+ && (mse *)AO_load(&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 &&
+ (mse *)AO_load(&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;
+ if (GC_print_stats == VERBOSE)
+ GC_log_printf("Finished mark helper %lu\n",
+ (unsigned long)id);
+ 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 <=
+ (mse *)AO_load((volatile AO_t *)(&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. */
+STATIC void GC_do_parallel_mark(void)
+{
+ mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
+
+ 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");
+ if (GC_print_stats == VERBOSE)
+ GC_log_printf("Starting marking for mark phase number %lu\n",
+ (unsigned long)GC_mark_no);
+ GC_first_nonempty = (AO_t)GC_mark_stack;
+ GC_active_count = 0;
+ GC_helper_count = 1;
+ GC_help_wanted = TRUE;
+ GC_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 */
+ if (GC_print_stats == VERBOSE)
+ GC_log_printf("Finished marking for mark phase number %lu\n",
+ (unsigned long)GC_mark_no);
+ GC_mark_no++;
+ GC_release_mark_lock();
+ GC_notify_all_marker();
+}
+
+
+/* Try to help out the marker, if it's running. */
+/* We do not hold the GC lock, but the requestor does. */
+GC_INNER void GC_help_marker(word my_mark_no)
+{
+ mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
+ unsigned my_id;
+
+ 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 >= (unsigned)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 n entries. */
+/* May silently fail. */
+static void alloc_mark_stack(size_t n)
+{
+ mse * new_stack = (mse *)GC_scratch_alloc(n * sizeof(struct GC_ms_entry));
+# ifdef GWW_VDB
+ /* Don't recycle a stack segment obtained with the wrong flags. */
+ /* Win32 GetWriteWatch requires the right kind of memory. */
+ static GC_bool GC_incremental_at_stack_alloc = FALSE;
+ GC_bool recycle_old = (!GC_incremental || GC_incremental_at_stack_alloc);
+
+ GC_incremental_at_stack_alloc = GC_incremental;
+# else
+# define recycle_old TRUE
+# endif
+
+ GC_mark_stack_too_small = FALSE;
+ if (GC_mark_stack_size != 0) {
+ if (new_stack != 0) {
+ if (recycle_old) {
+ /* Recycle old space */
+ size_t page_offset = (word)GC_mark_stack & (GC_page_size - 1);
+ size_t size = GC_mark_stack_size * sizeof(struct GC_ms_entry);
+ size_t displ = 0;
+
+ if (0 != page_offset) displ = GC_page_size - page_offset;
+ 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;
+ if (GC_print_stats) {
+ GC_log_printf("Grew mark stack to %lu frames\n",
+ (unsigned long) GC_mark_stack_size);
+ }
+ } else {
+ if (GC_print_stats) {
+ GC_log_printf("Failed to grow mark stack to %lu frames\n",
+ (unsigned long) n);
+ }
+ }
+ } else {
+ if (new_stack == 0) {
+ GC_err_printf("No space for mark stack\n");
+ EXIT();
+ }
+ GC_mark_stack = new_stack;
+ GC_mark_stack_size = n;
+ GC_mark_stack_limit = new_stack + n;
+ }
+ GC_mark_stack_top = GC_mark_stack-1;
+}
+
+GC_INNER void GC_mark_init(void)
+{
+ alloc_mark_stack(INITIAL_MARK_STACK_SIZE);
+}
+
+/*
+ * Push all locations between b and t onto the mark stack.
+ * b is the first location to be checked. t is one past the last
+ * location to be checked.
+ * Should only be used if there is no possibility of mark stack
+ * overflow.
+ */
+void GC_push_all(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 (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 = bottom;
+ GC_mark_stack_top -> mse_descr = length;
+}
+
+#ifndef GC_DISABLE_INCREMENTAL
+
+ /* Analogous to the above, but push only those pages h with */
+ /* dirty_fn(h) != 0. We use GC_push_all to actually push the block. */
+ /* Used both to selectively push dirty pages, or to push a block in */
+ /* piecemeal fashion, to allow for more marking concurrency. */
+ /* Will not overflow mark stack if GC_push_all pushes a small fixed */
+ /* number of entries. (This is invoked only if GC_push_all pushes */
+ /* a single entry, or if it marks each object before pushing it, thus */
+ /* ensuring progress in the event of a stack overflow.) */
+ STATIC void GC_push_selected(ptr_t bottom, ptr_t top,
+ GC_bool (*dirty_fn)(struct hblk *))
+ {
+ struct hblk * h;
+
+ bottom = (ptr_t)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
+ top = (ptr_t)(((word) top) & ~(ALIGNMENT-1));
+ if (bottom >= top) return;
+
+ h = HBLKPTR(bottom + HBLKSIZE);
+ if (top <= (ptr_t) h) {
+ if ((*dirty_fn)(h-1)) {
+ GC_push_all(bottom, top);
+ }
+ return;
+ }
+ if ((*dirty_fn)(h-1)) {
+ GC_push_all(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 */
+ GC_push_all((ptr_t)h, top);
+ return;
+ } else {
+ GC_push_all((ptr_t)h, (ptr_t)(h+1));
+ }
+ }
+ h++;
+ }
+
+ if ((ptr_t)h != top && (*dirty_fn)(h)) {
+ GC_push_all((ptr_t)h, top);
+ }
+ if (GC_mark_stack_top >= GC_mark_stack_limit) {
+ ABORT("Unexpected mark stack overflow");
+ }
+ }
+
+ void GC_push_conditional(ptr_t bottom, ptr_t top, GC_bool all)
+ {
+ if (!all) {
+ GC_push_selected(bottom, top, GC_page_was_dirty);
+ } else {
+# ifdef PROC_VDB
+ if (GC_dirty_maintained) {
+ /* Pages that were never dirtied cannot contain pointers. */
+ GC_push_selected(bottom, top, GC_page_was_ever_dirty);
+ } else
+# endif
+ /* else */ {
+ GC_push_all(bottom, top);
+ }
+ }
+ }
+#endif /* !GC_DISABLE_INCREMENTAL */
+
+#if defined(MSWIN32) || defined(MSWINCE)
+ void __cdecl GC_push_one(word p)
+#else
+ void GC_push_one(word p)
+#endif
+{
+ GC_PUSH_ONE_STACK(p, MARKED_FROM_REGISTER);
+}
+
+/*ARGSUSED*/
+GC_API struct GC_ms_entry * GC_CALL GC_mark_and_push(void *obj,
+ mse *mark_stack_ptr,
+ mse *mark_stack_limit,
+ void **src)
+{
+ hdr * hhdr;
+
+ PREFETCH(obj);
+ GET_HDR(obj, hhdr);
+ if (EXPECT(IS_FORWARDING_ADDR_OR_NIL(hhdr), FALSE)) {
+ if (GC_all_interior_pointers) {
+ hhdr = GC_find_header(GC_base(obj));
+ if (hhdr == 0) {
+ GC_ADD_TO_BLACK_LIST_NORMAL(obj, (ptr_t)src);
+ return mark_stack_ptr;
+ }
+ } else {
+ GC_ADD_TO_BLACK_LIST_NORMAL(obj, (ptr_t)src);
+ return mark_stack_ptr;
+ }
+ }
+ if (EXPECT(HBLK_IS_FREE(hhdr), FALSE)) {
+ GC_ADD_TO_BLACK_LIST_NORMAL(obj, (ptr_t)src);
+ return mark_stack_ptr;
+ }
+
+ PUSH_CONTENTS_HDR(obj, mark_stack_ptr /* modified */, mark_stack_limit,
+ (ptr_t)src, was_marked, hhdr, TRUE);
+ was_marked:
+ return mark_stack_ptr;
+}
+
+#if defined(MANUAL_VDB) && defined(THREADS)
+ void GC_dirty(ptr_t 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)
+ GC_INNER void GC_mark_and_push_stack(ptr_t p, ptr_t source)
+# else
+ GC_INNER void GC_mark_and_push_stack(ptr_t p)
+# define source ((ptr_t)0)
+# endif
+{
+ hdr * hhdr;
+ ptr_t r = p;
+
+ PREFETCH(p);
+ GET_HDR(p, hhdr);
+ if (EXPECT(IS_FORWARDING_ADDR_OR_NIL(hhdr), FALSE)) {
+ if (hhdr != 0) {
+ r = GC_base(p);
+ hhdr = HDR(r);
+ }
+ if (hhdr == 0) {
+ GC_ADD_TO_BLACK_LIST_STACK(p, source);
+ return;
+ }
+ }
+ if (EXPECT(HBLK_IS_FREE(hhdr), FALSE)) {
+ GC_ADD_TO_BLACK_LIST_NORMAL(p, source);
+ return;
+ }
+# if defined(MANUAL_VDB) && defined(THREADS)
+ /* Pointer is on the stack. We may have dirtied the object */
+ /* it points to, but not yet have called GC_dirty(); */
+ GC_dirty(p); /* Implicitly affects entire object. */
+# endif
+ PUSH_CONTENTS_HDR(r, GC_mark_stack_top, GC_mark_stack_limit,
+ source, mark_and_push_exit, hhdr, FALSE);
+ mark_and_push_exit: ;
+ /* We silently ignore pointers to near the end of a block, */
+ /* which is very mildly suboptimal. */
+ /* FIXME: We should probably add a header word to address */
+ /* this. */
+}
+# undef source
+
+# ifdef TRACE_BUF
+
+# define TRACE_ENTRIES 1000
+
+struct trace_entry {
+ char * kind;
+ word gc_no;
+ word bytes_allocd;
+ word arg1;
+ word arg2;
+} GC_trace_buf[TRACE_ENTRIES];
+
+int GC_trace_buf_ptr = 0;
+
+void GC_add_trace_entry(char *kind, word arg1, word arg2)
+{
+ GC_trace_buf[GC_trace_buf_ptr].kind = kind;
+ GC_trace_buf[GC_trace_buf_ptr].gc_no = GC_gc_no;
+ GC_trace_buf[GC_trace_buf_ptr].bytes_allocd = GC_bytes_allocd;
+ GC_trace_buf[GC_trace_buf_ptr].arg1 = arg1 ^ 0x80000000;
+ GC_trace_buf[GC_trace_buf_ptr].arg2 = arg2 ^ 0x80000000;
+ GC_trace_buf_ptr++;
+ if (GC_trace_buf_ptr >= TRACE_ENTRIES) GC_trace_buf_ptr = 0;
+}
+
+void GC_print_trace(word gc_no, GC_bool lock)
+{
+ int i;
+ struct trace_entry *p;
+ DCL_LOCK_STATE;
+
+ 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:%u,bytes:%lu) 0x%X, 0x%X\n",
+ p -> kind, (unsigned)p -> gc_no,
+ (unsigned long)p -> bytes_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.
+ */
+GC_INNER void GC_push_all_eager(ptr_t bottom, ptr_t top)
+{
+ word * b = (word *)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
+ word * t = (word *)(((word) top) & ~(ALIGNMENT-1));
+ register word *p;
+ register word q;
+ register word *lim;
+ register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
+ register ptr_t least_ha = GC_least_plausible_heap_addr;
+# define GC_greatest_plausible_heap_addr greatest_ha
+# define GC_least_plausible_heap_addr least_ha
+
+ if (top == 0) return;
+ /* check all pointers in range and push if they appear */
+ /* to be valid. */
+ lim = t - 1 /* longword */;
+ for (p = b; p <= lim; p = (word *)(((ptr_t)p) + ALIGNMENT)) {
+ q = *p;
+ GC_PUSH_ONE_STACK(q, p);
+ }
+# undef GC_greatest_plausible_heap_addr
+# undef GC_least_plausible_heap_addr
+}
+
+GC_INNER void GC_push_all_stack(ptr_t bottom, ptr_t top)
+{
+# if defined(THREADS) && defined(MPROTECT_VDB)
+ GC_push_all_eager(bottom, top);
+# else
+ if (!NEED_FIXUP_POINTER && GC_all_interior_pointers) {
+ GC_push_all(bottom, top);
+ } else {
+ GC_push_all_eager(bottom, top);
+ }
+# endif
+}
+
+#if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES) && \
+ defined(MARK_BIT_PER_GRANULE)
+# if GC_GRANULE_WORDS == 1
+# define USE_PUSH_MARKED_ACCELERATORS
+# define PUSH_GRANULE(q) \
+ { word qcontents = (q)[0]; \
+ GC_PUSH_ONE_HEAP(qcontents, (q)); }
+# elif GC_GRANULE_WORDS == 2
+# define USE_PUSH_MARKED_ACCELERATORS
+# define PUSH_GRANULE(q) \
+ { word qcontents = (q)[0]; \
+ GC_PUSH_ONE_HEAP(qcontents, (q)); \
+ qcontents = (q)[1]; \
+ GC_PUSH_ONE_HEAP(qcontents, (q)+1); }
+# elif GC_GRANULE_WORDS == 4
+# define USE_PUSH_MARKED_ACCELERATORS
+# define PUSH_GRANULE(q) \
+ { word qcontents = (q)[0]; \
+ GC_PUSH_ONE_HEAP(qcontents, (q)); \
+ qcontents = (q)[1]; \
+ GC_PUSH_ONE_HEAP(qcontents, (q)+1); \
+ qcontents = (q)[2]; \
+ GC_PUSH_ONE_HEAP(qcontents, (q)+2); \
+ qcontents = (q)[3]; \
+ GC_PUSH_ONE_HEAP(qcontents, (q)+3); }
+# endif
+#endif /* !USE_MARK_BYTES && MARK_BIT_PER_GRANULE */
+
+#ifdef USE_PUSH_MARKED_ACCELERATORS
+/* Push all objects reachable from marked objects in the given block */
+/* containing objects of size 1 granule. */
+STATIC void GC_push_marked1(struct hblk *h, hdr *hhdr)
+{
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
+ word *p;
+ word *plim;
+ word *q;
+ word mark_word;
+
+ /* Allow registers to be used for some frequently acccessed */
+ /* global variables. Otherwise aliasing issues are likely */
+ /* to prevent that. */
+ ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
+ ptr_t least_ha = GC_least_plausible_heap_addr;
+ mse * mark_stack_top = GC_mark_stack_top;
+ 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++;
+ q = p;
+ while(mark_word != 0) {
+ if (mark_word & 1) {
+ PUSH_GRANULE(q);
+ }
+ q += GC_GRANULE_WORDS;
+ mark_word >>= 1;
+ }
+ p += WORDSZ*GC_GRANULE_WORDS;
+ }
+
+# undef GC_greatest_plausible_heap_addr
+# undef GC_least_plausible_heap_addr
+# undef GC_mark_stack_top
+# undef GC_mark_stack_limit
+
+ GC_mark_stack_top = mark_stack_top;
+}
+
+
+#ifndef UNALIGNED_PTRS
+
+/* Push all objects reachable from marked objects in the given block */
+/* of size 2 (granules) objects. */
+STATIC void GC_push_marked2(struct hblk *h, hdr *hhdr)
+{
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
+ word *p;
+ word *plim;
+ word *q;
+ word mark_word;
+
+ ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
+ ptr_t least_ha = GC_least_plausible_heap_addr;
+ mse * mark_stack_top = GC_mark_stack_top;
+ 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++;
+ q = p;
+ while(mark_word != 0) {
+ if (mark_word & 1) {
+ PUSH_GRANULE(q);
+ PUSH_GRANULE(q + GC_GRANULE_WORDS);
+ }
+ q += 2 * GC_GRANULE_WORDS;
+ mark_word >>= 2;
+ }
+ p += WORDSZ*GC_GRANULE_WORDS;
+ }
+
+# undef GC_greatest_plausible_heap_addr
+# undef GC_least_plausible_heap_addr
+# undef GC_mark_stack_top
+# undef GC_mark_stack_limit
+
+ GC_mark_stack_top = mark_stack_top;
+}
+
+# if GC_GRANULE_WORDS < 4
+/* Push all objects reachable from marked objects in the given block */
+/* of size 4 (granules) objects. */
+/* There is a risk of mark stack overflow here. But we handle that. */
+/* And only unmarked objects get pushed, so it's not very likely. */
+STATIC void GC_push_marked4(struct hblk *h, hdr *hhdr)
+{
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
+ word *p;
+ word *plim;
+ word *q;
+ word mark_word;
+
+ ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
+ ptr_t least_ha = GC_least_plausible_heap_addr;
+ mse * mark_stack_top = GC_mark_stack_top;
+ 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++;
+ q = p;
+ while(mark_word != 0) {
+ if (mark_word & 1) {
+ PUSH_GRANULE(q);
+ PUSH_GRANULE(q + GC_GRANULE_WORDS);
+ PUSH_GRANULE(q + 2*GC_GRANULE_WORDS);
+ PUSH_GRANULE(q + 3*GC_GRANULE_WORDS);
+ }
+ q += 4 * GC_GRANULE_WORDS;
+ mark_word >>= 4;
+ }
+ p += WORDSZ*GC_GRANULE_WORDS;
+ }
+# undef GC_greatest_plausible_heap_addr
+# undef GC_least_plausible_heap_addr
+# undef GC_mark_stack_top
+# undef GC_mark_stack_limit
+ GC_mark_stack_top = mark_stack_top;
+}
+
+#endif /* GC_GRANULE_WORDS < 4 */
+
+#endif /* UNALIGNED_PTRS */
+
+#endif /* USE_PUSH_MARKED_ACCELERATORS */
+
+/* Push all objects reachable from marked objects in the given block */
+STATIC void GC_push_marked(struct hblk *h, hdr *hhdr)
+{
+ size_t sz = hhdr -> hb_sz;
+ word descr = hhdr -> hb_descr;
+ ptr_t p;
+ word bit_no;
+ ptr_t lim;
+ mse * GC_mark_stack_top_reg;
+ mse * mark_stack_limit = GC_mark_stack_limit;
+
+ /* Some quick shortcuts: */
+ if ((0 | GC_DS_LENGTH) == descr) return;
+ if (GC_block_empty(hhdr)/* nothing marked */) return;
+ GC_n_rescuing_pages++;
+ GC_objects_are_marked = TRUE;
+ if (sz > MAXOBJBYTES) {
+ lim = h -> hb_body;
+ } else {
+ lim = (h + 1)->hb_body - sz;
+ }
+
+ switch(BYTES_TO_GRANULES(sz)) {
+# if defined(USE_PUSH_MARKED_ACCELERATORS)
+ case 1:
+ GC_push_marked1(h, hhdr);
+ break;
+# if !defined(UNALIGNED_PTRS)
+ case 2:
+ GC_push_marked2(h, hhdr);
+ break;
+# if GC_GRANULE_WORDS < 4
+ case 4:
+ GC_push_marked4(h, hhdr);
+ break;
+# endif
+# endif
+# endif
+ default:
+ GC_mark_stack_top_reg = GC_mark_stack_top;
+ for (p = h -> hb_body, bit_no = 0; p <= lim;
+ p += sz, bit_no += MARK_BIT_OFFSET(sz)) {
+ if (mark_bit_from_hdr(hhdr, bit_no)) {
+ /* Mark from fields inside the object */
+ PUSH_OBJ(p, hhdr, GC_mark_stack_top_reg, mark_stack_limit);
+ }
+ }
+ GC_mark_stack_top = GC_mark_stack_top_reg;
+ }
+}
+
+#ifndef GC_DISABLE_INCREMENTAL
+ /* Test whether any page in the given block is dirty. */
+ STATIC GC_bool GC_block_was_dirty(struct hblk *h, hdr *hhdr)
+ {
+ size_t sz = hhdr -> hb_sz;
+
+ if (sz <= MAXOBJBYTES) {
+ return(GC_page_was_dirty(h));
+ } else {
+ ptr_t p = (ptr_t)h;
+ while (p < (ptr_t)h + sz) {
+ if (GC_page_was_dirty((struct hblk *)p)) return(TRUE);
+ p += HBLKSIZE;
+ }
+ return(FALSE);
+ }
+ }
+#endif /* GC_DISABLE_INCREMENTAL */
+
+/* Similar to GC_push_marked, but skip over unallocated blocks */
+/* and return address of next plausible block. */
+STATIC struct hblk * GC_push_next_marked(struct hblk *h)
+{
+ hdr * hhdr = HDR(h);
+
+ if (EXPECT(IS_FORWARDING_ADDR_OR_NIL(hhdr) || HBLK_IS_FREE(hhdr), FALSE)) {
+ h = GC_next_used_block(h);
+ if (h == 0) return(0);
+ hhdr = GC_find_header((ptr_t)h);
+ }
+ GC_push_marked(h, hhdr);
+ return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
+}
+
+#ifndef GC_DISABLE_INCREMENTAL
+ /* Identical to above, but mark only from dirty pages */
+ STATIC struct hblk * GC_push_next_marked_dirty(struct hblk *h)
+ {
+ hdr * hhdr = HDR(h);
+
+ if (!GC_dirty_maintained) ABORT("Dirty bits not set up");
+ for (;;) {
+ if (EXPECT(IS_FORWARDING_ADDR_OR_NIL(hhdr)
+ || HBLK_IS_FREE(hhdr), FALSE)) {
+ h = GC_next_used_block(h);
+ if (h == 0) return(0);
+ hhdr = GC_find_header((ptr_t)h);
+ }
+# 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);
+ hhdr = HDR(h);
+ }
+ GC_push_marked(h, hhdr);
+ return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
+ }
+#endif /* !GC_DISABLE_INCREMENTAL */
+
+/* Similar to above, but for uncollectable pages. Needed since we */
+/* do not clear marks for such pages, even for full collections. */
+STATIC struct hblk * GC_push_next_marked_uncollectable(struct hblk *h)
+{
+ hdr * hhdr = HDR(h);
+
+ for (;;) {
+ if (EXPECT(IS_FORWARDING_ADDR_OR_NIL(hhdr)
+ || HBLK_IS_FREE(hhdr), FALSE)) {
+ h = GC_next_used_block(h);
+ if (h == 0) return(0);
+ hhdr = GC_find_header((ptr_t)h);
+ }
+ if (hhdr -> hb_obj_kind == UNCOLLECTABLE) break;
+ h += OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
+ hhdr = HDR(h);
+ }
+ GC_push_marked(h, hhdr);
+ return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
+}
projects / hs-boehmgc.git / blobdiff