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+/*
+ * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
+ * Copyright (c) 2001 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.
+ *
+ */
+
+/* Private declarations of GC marker data structures and macros */
+
+/*
+ * Declarations of mark stack. Needed by marker and client supplied mark
+ * routines. Transitively include gc_priv.h.
+ * (Note that gc_priv.h should not be included before this, since this
+ * includes dbg_mlc.h, which wants to include gc_priv.h AFTER defining
+ * I_HIDE_POINTERS.)
+ */
+#ifndef GC_PMARK_H
+# define GC_PMARK_H
+
+# if defined(KEEP_BACK_PTRS) || defined(PRINT_BLACK_LIST)
+# include "dbg_mlc.h"
+# endif
+# ifndef GC_MARK_H
+# include "../gc_mark.h"
+# endif
+# ifndef GC_PRIVATE_H
+# include "gc_priv.h"
+# endif
+
+/* The real declarations of the following is in gc_priv.h, so that */
+/* we can avoid scanning the following table. */
+/*
+extern mark_proc GC_mark_procs[MAX_MARK_PROCS];
+*/
+
+/*
+ * Mark descriptor stuff that should remain private for now, mostly
+ * because it's hard to export WORDSZ without including gcconfig.h.
+ */
+# define BITMAP_BITS (WORDSZ - GC_DS_TAG_BITS)
+# define PROC(descr) \
+ (GC_mark_procs[((descr) >> GC_DS_TAG_BITS) & (GC_MAX_MARK_PROCS-1)])
+# define ENV(descr) \
+ ((descr) >> (GC_DS_TAG_BITS + GC_LOG_MAX_MARK_PROCS))
+# define MAX_ENV \
+ (((word)1 << (WORDSZ - GC_DS_TAG_BITS - GC_LOG_MAX_MARK_PROCS)) - 1)
+
+
+extern word GC_n_mark_procs;
+
+/* Number of mark stack entries to discard on overflow. */
+#define GC_MARK_STACK_DISCARDS (INITIAL_MARK_STACK_SIZE/8)
+
+typedef struct GC_ms_entry {
+ GC_word * mse_start; /* First word of object */
+ GC_word mse_descr; /* Descriptor; low order two bits are tags, */
+ /* identifying the upper 30 bits as one of the */
+ /* following: */
+} mse;
+
+extern word GC_mark_stack_size;
+
+extern mse * GC_mark_stack_limit;
+
+#ifdef PARALLEL_MARK
+ extern mse * VOLATILE GC_mark_stack_top;
+#else
+ extern mse * GC_mark_stack_top;
+#endif
+
+extern mse * GC_mark_stack;
+
+#ifdef PARALLEL_MARK
+ /*
+ * Allow multiple threads to participate in the marking process.
+ * This works roughly as follows:
+ * The main mark stack never shrinks, but it can grow.
+ *
+ * The initiating threads holds the GC lock, and sets GC_help_wanted.
+ *
+ * Other threads:
+ * 1) update helper_count (while holding mark_lock.)
+ * 2) allocate a local mark stack
+ * repeatedly:
+ * 3) Steal a global mark stack entry by atomically replacing
+ * its descriptor with 0.
+ * 4) Copy it to the local stack.
+ * 5) Mark on the local stack until it is empty, or
+ * it may be profitable to copy it back.
+ * 6) If necessary, copy local stack to global one,
+ * holding mark lock.
+ * 7) Stop when the global mark stack is empty.
+ * 8) decrement helper_count (holding mark_lock).
+ *
+ * This is an experiment to see if we can do something along the lines
+ * of the University of Tokyo SGC in a less intrusive, though probably
+ * also less performant, way.
+ */
+ void GC_do_parallel_mark();
+ /* inititate parallel marking. */
+
+ extern GC_bool GC_help_wanted; /* Protected by mark lock */
+ extern unsigned GC_helper_count; /* Number of running helpers. */
+ /* Protected by mark lock */
+ extern unsigned GC_active_count; /* 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_mark_stack_top is also protected by mark lock. */
+ extern mse * VOLATILE GC_first_nonempty;
+ /* Lowest entry on mark stack */
+ /* that may be nonempty. */
+ /* Updated only by initiating */
+ /* thread. */
+ /*
+ * GC_notify_all_marker() is used when GC_help_wanted is first set,
+ * when the last helper becomes inactive,
+ * when something is added to the global mark stack, and just after
+ * GC_mark_no is incremented.
+ * This could be split into multiple CVs (and probably should be to
+ * scale to really large numbers of processors.)
+ */
+#endif /* PARALLEL_MARK */
+
+/* Return a pointer to within 1st page of object. */
+/* Set *new_hdr_p to corr. hdr. */
+#ifdef __STDC__
+# ifdef PRINT_BLACK_LIST
+ ptr_t GC_find_start(ptr_t current, hdr *hhdr, hdr **new_hdr_p, word source);
+# else
+ ptr_t GC_find_start(ptr_t current, hdr *hhdr, hdr **new_hdr_p);
+# endif
+#else
+ ptr_t GC_find_start();
+#endif
+
+mse * GC_signal_mark_stack_overflow();
+
+# ifdef GATHERSTATS
+# define ADD_TO_ATOMIC(sz) GC_atomic_in_use += (sz)
+# define ADD_TO_COMPOSITE(sz) GC_composite_in_use += (sz)
+# else
+# define ADD_TO_ATOMIC(sz)
+# define ADD_TO_COMPOSITE(sz)
+# endif
+
+/* Push the object obj with corresponding heap block header hhdr onto */
+/* the mark stack. */
+# define PUSH_OBJ(obj, hhdr, mark_stack_top, mark_stack_limit) \
+{ \
+ register word _descr = (hhdr) -> hb_descr; \
+ \
+ if (_descr == 0) { \
+ ADD_TO_ATOMIC((hhdr) -> hb_sz); \
+ } else { \
+ ADD_TO_COMPOSITE((hhdr) -> hb_sz); \
+ mark_stack_top++; \
+ if (mark_stack_top >= mark_stack_limit) { \
+ mark_stack_top = GC_signal_mark_stack_overflow(mark_stack_top); \
+ } \
+ mark_stack_top -> mse_start = (obj); \
+ mark_stack_top -> mse_descr = _descr; \
+ } \
+}
+
+#ifdef PRINT_BLACK_LIST
+# define GC_FIND_START(current, hhdr, new_hdr_p, source) \
+ GC_find_start(current, hhdr, new_hdr_p, source)
+#else
+# define GC_FIND_START(current, hhdr, new_hdr_p, source) \
+ GC_find_start(current, hhdr, new_hdr_p)
+#endif
+
+/* Push the contents of current onto the mark stack if it is a valid */
+/* ptr to a currently unmarked object. Mark it. */
+/* If we assumed a standard-conforming compiler, we could probably */
+/* generate the exit_label transparently. */
+# define PUSH_CONTENTS(current, mark_stack_top, mark_stack_limit, \
+ source, exit_label) \
+{ \
+ hdr * my_hhdr; \
+ ptr_t my_current = current; \
+ \
+ GET_HDR(my_current, my_hhdr); \
+ if (IS_FORWARDING_ADDR_OR_NIL(my_hhdr)) { \
+ hdr * new_hdr = GC_invalid_header; \
+ my_current = GC_FIND_START(my_current, my_hhdr, \
+ &new_hdr, (word)source); \
+ my_hhdr = new_hdr; \
+ } \
+ PUSH_CONTENTS_HDR(my_current, mark_stack_top, mark_stack_limit, \
+ source, exit_label, my_hhdr); \
+exit_label: ; \
+}
+
+/* As above, but use header cache for header lookup. */
+# define HC_PUSH_CONTENTS(current, mark_stack_top, mark_stack_limit, \
+ source, exit_label) \
+{ \
+ hdr * my_hhdr; \
+ ptr_t my_current = current; \
+ \
+ HC_GET_HDR(my_current, my_hhdr, source); \
+ PUSH_CONTENTS_HDR(my_current, mark_stack_top, mark_stack_limit, \
+ source, exit_label, my_hhdr); \
+exit_label: ; \
+}
+
+/* Set mark bit, exit if it was already set. */
+
+# ifdef USE_MARK_BYTES
+ /* Unlike the mark bit case, there is a race here, and we may set */
+ /* the bit twice in the concurrent case. This can result in the */
+ /* object being pushed twice. But that's only a performance issue. */
+# define SET_MARK_BIT_EXIT_IF_SET(hhdr,displ,exit_label) \
+ { \
+ register VOLATILE char * mark_byte_addr = \
+ hhdr -> hb_marks + ((displ) >> 1); \
+ register char mark_byte = *mark_byte_addr; \
+ \
+ if (mark_byte) goto exit_label; \
+ *mark_byte_addr = 1; \
+ }
+# else
+# define SET_MARK_BIT_EXIT_IF_SET(hhdr,displ,exit_label) \
+ { \
+ register word * mark_word_addr = hhdr -> hb_marks + divWORDSZ(displ); \
+ register word mark_word = *mark_word_addr; \
+ \
+ OR_WORD_EXIT_IF_SET(mark_word_addr, (word)1 << modWORDSZ(displ), \
+ exit_label); \
+ }
+# endif /* USE_MARK_BYTES */
+
+/* If the mark bit corresponding to current is not set, set it, and */
+/* push the contents of the object on the mark stack. For a small */
+/* object we assume that current is the (possibly interior) pointer */
+/* to the object. For large objects we assume that current points */
+/* to somewhere inside the first page of the object. If */
+/* GC_all_interior_pointers is set, it may have been previously */
+/* adjusted to make that true. */
+# define PUSH_CONTENTS_HDR(current, mark_stack_top, mark_stack_limit, \
+ source, exit_label, hhdr) \
+{ \
+ int displ; /* Displacement in block; first bytes, then words */ \
+ int map_entry; \
+ \
+ displ = HBLKDISPL(current); \
+ map_entry = MAP_ENTRY((hhdr -> hb_map), displ); \
+ displ = BYTES_TO_WORDS(displ); \
+ if (map_entry > CPP_MAX_OFFSET) { \
+ if (map_entry == OFFSET_TOO_BIG) { \
+ map_entry = displ % (hhdr -> hb_sz); \
+ displ -= map_entry; \
+ if (displ + (hhdr -> hb_sz) > BYTES_TO_WORDS(HBLKSIZE)) { \
+ GC_ADD_TO_BLACK_LIST_NORMAL((word)current, source); \
+ goto exit_label; \
+ } \
+ } else { \
+ GC_ADD_TO_BLACK_LIST_NORMAL((word)current, source); goto exit_label; \
+ } \
+ } else { \
+ displ -= map_entry; \
+ } \
+ GC_ASSERT(displ >= 0 && displ < MARK_BITS_PER_HBLK); \
+ SET_MARK_BIT_EXIT_IF_SET(hhdr, displ, exit_label); \
+ GC_STORE_BACK_PTR((ptr_t)source, (ptr_t)HBLKPTR(current) \
+ + WORDS_TO_BYTES(displ)); \
+ PUSH_OBJ(((word *)(HBLKPTR(current)) + displ), hhdr, \
+ mark_stack_top, mark_stack_limit) \
+}
+
+#if defined(PRINT_BLACK_LIST) || defined(KEEP_BACK_PTRS)
+# define PUSH_ONE_CHECKED_STACK(p, source) \
+ GC_mark_and_push_stack(p, (ptr_t)(source))
+#else
+# define PUSH_ONE_CHECKED_STACK(p, source) \
+ GC_mark_and_push_stack(p)
+#endif
+
+/*
+ * Push a single value onto mark stack. Mark from the object pointed to by p.
+ * P is considered valid even if it is an interior pointer.
+ * Previously marked objects are not pushed. Hence we make progress even
+ * if the mark stack overflows.
+ */
+# define GC_PUSH_ONE_STACK(p, source) \
+ if ((ptr_t)(p) >= (ptr_t)GC_least_plausible_heap_addr \
+ && (ptr_t)(p) < (ptr_t)GC_greatest_plausible_heap_addr) { \
+ PUSH_ONE_CHECKED_STACK(p, source); \
+ }
+
+/*
+ * As above, but interior pointer recognition as for
+ * normal for heap pointers.
+ */
+# define GC_PUSH_ONE_HEAP(p,source) \
+ if ((ptr_t)(p) >= (ptr_t)GC_least_plausible_heap_addr \
+ && (ptr_t)(p) < (ptr_t)GC_greatest_plausible_heap_addr) { \
+ GC_mark_stack_top = GC_mark_and_push( \
+ (GC_PTR)(p), GC_mark_stack_top, \
+ GC_mark_stack_limit, (GC_PTR *)(source)); \
+ }
+
+/* Mark starting at mark stack entry top (incl.) down to */
+/* mark stack entry bottom (incl.). Stop after performing */
+/* about one page worth of work. Return the new mark stack */
+/* top entry. */
+mse * GC_mark_from GC_PROTO((mse * top, mse * bottom, mse *limit));
+
+#define MARK_FROM_MARK_STACK() \
+ GC_mark_stack_top = GC_mark_from(GC_mark_stack_top, \
+ GC_mark_stack, \
+ GC_mark_stack + GC_mark_stack_size);
+
+/*
+ * Mark from one finalizable object using the specified
+ * mark proc. May not mark the object pointed to by
+ * real_ptr. That is the job of the caller, if appropriate
+ */
+# define GC_MARK_FO(real_ptr, mark_proc) \
+{ \
+ (*(mark_proc))(real_ptr); \
+ while (!GC_mark_stack_empty()) MARK_FROM_MARK_STACK(); \
+ if (GC_mark_state != MS_NONE) { \
+ GC_set_mark_bit(real_ptr); \
+ while (!GC_mark_some((ptr_t)0)) {} \
+ } \
+}
+
+extern GC_bool GC_mark_stack_too_small;
+ /* We need a larger mark stack. May be */
+ /* set by client supplied mark routines.*/
+
+typedef int mark_state_t; /* Current state of marking, as follows:*/
+ /* Used to remember where we are during */
+ /* concurrent marking. */
+
+ /* We say something is dirty if it was */
+ /* written since the last time we */
+ /* retrieved dirty bits. We say it's */
+ /* grungy if it was marked dirty in the */
+ /* last set of bits we retrieved. */
+
+ /* Invariant I: all roots and marked */
+ /* objects p are either dirty, or point */
+ /* to objects q that are either marked */
+ /* or a pointer to q appears in a range */
+ /* on the mark stack. */
+
+# define MS_NONE 0 /* No marking in progress. I holds. */
+ /* Mark stack is empty. */
+
+# define MS_PUSH_RESCUERS 1 /* Rescuing objects are currently */
+ /* being pushed. I holds, except */
+ /* that grungy roots may point to */
+ /* unmarked objects, as may marked */
+ /* grungy objects above scan_ptr. */
+
+# define MS_PUSH_UNCOLLECTABLE 2
+ /* I holds, except that marked */
+ /* uncollectable objects above scan_ptr */
+ /* may point to unmarked objects. */
+ /* Roots may point to unmarked objects */
+
+# define MS_ROOTS_PUSHED 3 /* I holds, mark stack may be nonempty */
+
+# define MS_PARTIALLY_INVALID 4 /* I may not hold, e.g. because of M.S. */
+ /* overflow. However marked heap */
+ /* objects below scan_ptr point to */
+ /* marked or stacked objects. */
+
+# define MS_INVALID 5 /* I may not hold. */
+
+extern mark_state_t GC_mark_state;
+
+#endif /* GC_PMARK_H */
+