/libs/headers/gc/private/gc_pmark.h
http://github.com/nddrylliog/ooc · C++ Header · 493 lines · 297 code · 48 blank · 148 comment · 66 complexity · 303e7a6a870d20e29211477a33f5bc5b MD5 · raw file
- /*
- * 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 unsigned 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 {
- ptr_t mse_start; /* First word of object, word aligned */
- GC_word mse_descr; /* Descriptor; low order two bits are tags, */
- /* as described in gc_mark.h. */
- } mse;
- extern size_t 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. */
- /*
- * 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. */
- ptr_t GC_find_start(ptr_t current, hdr *hhdr, hdr **new_hdr_p);
- mse * GC_signal_mark_stack_overflow(mse *msp);
- /* 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) { \
- 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; \
- } \
- }
- /* 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; \
- \
- HC_GET_HDR(current, my_hhdr, source, exit_label); \
- PUSH_CONTENTS_HDR(current, mark_stack_top, mark_stack_limit, \
- source, exit_label, my_hhdr, TRUE); \
- exit_label: ; \
- }
- /* Set mark bit, exit if it was already set. */
- # ifdef USE_MARK_BITS
- # ifdef PARALLEL_MARK
- /* The following may fail to exit even if the bit was already set. */
- /* For our uses, that's benign: */
- # define OR_WORD_EXIT_IF_SET(addr, bits, exit_label) \
- { \
- if (!(*(addr) & (mask))) { \
- AO_or((AO_t *)(addr), (mask); \
- } else { \
- goto label; \
- } \
- }
- # else
- # define OR_WORD_EXIT_IF_SET(addr, bits, exit_label) \
- { \
- word old = *(addr); \
- word my_bits = (bits); \
- if (old & my_bits) goto exit_label; \
- *(addr) = (old | my_bits); \
- }
- # endif /* !PARALLEL_MARK */
- # define SET_MARK_BIT_EXIT_IF_SET(hhdr,bit_no,exit_label) \
- { \
- word * mark_word_addr = hhdr -> hb_marks + divWORDSZ(bit_no); \
- \
- OR_WORD_EXIT_IF_SET(mark_word_addr, (word)1 << modWORDSZ(bit_no), \
- exit_label); \
- }
- # endif
- #ifdef USE_MARK_BYTES
- # if defined(I386) && defined(__GNUC__)
- # define LONG_MULT(hprod, lprod, x, y) { \
- asm("mull %2" : "=a"(lprod), "=d"(hprod) : "g"(y), "0"(x)); \
- }
- # else /* No in-line X86 assembly code */
- # define LONG_MULT(hprod, lprod, x, y) { \
- unsigned long long prod = (unsigned long long)x \
- * (unsigned long long)y; \
- hprod = prod >> 32; \
- lprod = (unsigned32)prod; \
- }
- # endif
- /* 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,bit_no,exit_label) \
- { \
- char * mark_byte_addr = (char *)hhdr -> hb_marks + (bit_no); \
- char mark_byte = *mark_byte_addr; \
- \
- if (mark_byte) goto exit_label; \
- *mark_byte_addr = 1; \
- }
- #endif /* USE_MARK_BYTES */
- #ifdef PARALLEL_MARK
- # define INCR_MARKS(hhdr) \
- AO_store(&(hhdr -> hb_n_marks), AO_load(&(hhdr -> hb_n_marks))+1);
- #else
- # define INCR_MARKS(hhdr) ++(hhdr -> hb_n_marks)
- #endif
- #ifdef ENABLE_TRACE
- # define TRACE(source, cmd) \
- if (GC_trace_addr != 0 && (ptr_t)(source) == GC_trace_addr) cmd
- # define TRACE_TARGET(target, cmd) \
- if (GC_trace_addr != 0 && (target) == *(ptr_t *)GC_trace_addr) cmd
- #else
- # define TRACE(source, cmd)
- # define TRACE_TARGET(source, cmd)
- #endif
- /* If the mark bit corresponding to current is not set, set it, and */
- /* push the contents of the object on the mark stack. Current points */
- /* to the bginning of the object. We rely on the fact that the */
- /* preceding header calculation will succeed for a pointer past the */
- /* first page of an object, only if it is in fact a valid pointer */
- /* to the object. Thus we can omit the otherwise necessary tests */
- /* here. Note in particular that the "displ" value is the displacement */
- /* from the beginning of the heap block, which may itself be in the */
- /* interior of a large object. */
- #ifdef MARK_BIT_PER_GRANULE
- # define PUSH_CONTENTS_HDR(current, mark_stack_top, mark_stack_limit, \
- source, exit_label, hhdr, do_offset_check) \
- { \
- size_t displ = HBLKDISPL(current); /* Displacement in block; in bytes. */\
- /* displ is always within range. If current doesn't point to */ \
- /* first block, then we are in the all_interior_pointers case, and */ \
- /* it is safe to use any displacement value. */ \
- size_t gran_displ = BYTES_TO_GRANULES(displ); \
- size_t gran_offset = hhdr -> hb_map[gran_displ]; \
- size_t byte_offset = displ & (GRANULE_BYTES - 1); \
- ptr_t base = current; \
- /* The following always fails for large block references. */ \
- if (EXPECT((gran_offset | byte_offset) != 0, FALSE)) { \
- if (hhdr -> hb_large_block) { \
- /* gran_offset is bogus. */ \
- size_t obj_displ; \
- base = (ptr_t)(hhdr -> hb_block); \
- obj_displ = (ptr_t)(current) - base; \
- if (obj_displ != displ) { \
- GC_ASSERT(obj_displ < hhdr -> hb_sz); \
- /* Must be in all_interior_pointer case, not first block */ \
- /* already did validity check on cache miss. */ \
- ; \
- } else { \
- if (do_offset_check && !GC_valid_offsets[obj_displ]) { \
- GC_ADD_TO_BLACK_LIST_NORMAL(current, source); \
- goto exit_label; \
- } \
- } \
- gran_displ = 0; \
- GC_ASSERT(hhdr -> hb_sz > HBLKSIZE || \
- hhdr -> hb_block == HBLKPTR(current)); \
- GC_ASSERT((ptr_t)(hhdr -> hb_block) <= (ptr_t) current); \
- } else { \
- size_t obj_displ = GRANULES_TO_BYTES(gran_offset) \
- + byte_offset; \
- if (do_offset_check && !GC_valid_offsets[obj_displ]) { \
- GC_ADD_TO_BLACK_LIST_NORMAL(current, source); \
- goto exit_label; \
- } \
- gran_displ -= gran_offset; \
- base -= obj_displ; \
- } \
- } \
- GC_ASSERT(hhdr == GC_find_header(base)); \
- GC_ASSERT(gran_displ % BYTES_TO_GRANULES(hhdr -> hb_sz) == 0); \
- TRACE(source, GC_log_printf("GC:%d: passed validity tests\n",GC_gc_no)); \
- SET_MARK_BIT_EXIT_IF_SET(hhdr, gran_displ, exit_label); \
- TRACE(source, GC_log_printf("GC:%d: previously unmarked\n",GC_gc_no)); \
- TRACE_TARGET(base, \
- GC_log_printf("GC:%d: marking %p from %p instead\n", GC_gc_no, \
- base, source)); \
- INCR_MARKS(hhdr); \
- GC_STORE_BACK_PTR((ptr_t)source, base); \
- PUSH_OBJ(base, hhdr, mark_stack_top, mark_stack_limit); \
- }
- #endif /* MARK_BIT_PER_GRANULE */
- #ifdef MARK_BIT_PER_OBJ
- # define PUSH_CONTENTS_HDR(current, mark_stack_top, mark_stack_limit, \
- source, exit_label, hhdr, do_offset_check) \
- { \
- size_t displ = HBLKDISPL(current); /* Displacement in block; in bytes. */\
- unsigned32 low_prod, high_prod, offset_fraction; \
- unsigned32 inv_sz = hhdr -> hb_inv_sz; \
- ptr_t base = current; \
- LONG_MULT(high_prod, low_prod, displ, inv_sz); \
- /* product is > and within sz_in_bytes of displ * sz_in_bytes * 2**32 */ \
- if (EXPECT(low_prod >> 16 != 0, FALSE)) { \
- FIXME: fails if offset is a multiple of HBLKSIZE which becomes 0 \
- if (inv_sz == LARGE_INV_SZ) { \
- size_t obj_displ; \
- base = (ptr_t)(hhdr -> hb_block); \
- obj_displ = (ptr_t)(current) - base; \
- if (obj_displ != displ) { \
- GC_ASSERT(obj_displ < hhdr -> hb_sz); \
- /* Must be in all_interior_pointer case, not first block */ \
- /* already did validity check on cache miss. */ \
- ; \
- } else { \
- if (do_offset_check && !GC_valid_offsets[obj_displ]) { \
- GC_ADD_TO_BLACK_LIST_NORMAL(current, source); \
- goto exit_label; \
- } \
- } \
- GC_ASSERT(hhdr -> hb_sz > HBLKSIZE || \
- hhdr -> hb_block == HBLKPTR(current)); \
- GC_ASSERT((ptr_t)(hhdr -> hb_block) < (ptr_t) current); \
- } else { \
- /* Accurate enough if HBLKSIZE <= 2**15. */ \
- GC_ASSERT(HBLKSIZE <= (1 << 15)); \
- size_t obj_displ = (((low_prod >> 16) + 1) * (hhdr -> hb_sz)) >> 16; \
- if (do_offset_check && !GC_valid_offsets[obj_displ]) { \
- GC_ADD_TO_BLACK_LIST_NORMAL(current, source); \
- goto exit_label; \
- } \
- base -= obj_displ; \
- } \
- } \
- /* May get here for pointer to start of block not at */ \
- /* beginning of object. If so, it's valid, and we're fine. */ \
- GC_ASSERT(high_prod >= 0 && high_prod <= HBLK_OBJS(hhdr -> hb_sz)); \
- TRACE(source, GC_log_printf("GC:%d: passed validity tests\n",GC_gc_no)); \
- SET_MARK_BIT_EXIT_IF_SET(hhdr, high_prod, exit_label); \
- TRACE(source, GC_log_printf("GC:%d: previously unmarked\n",GC_gc_no)); \
- TRACE_TARGET(base, \
- GC_log_printf("GC:%d: marking %p from %p instead\n", GC_gc_no, \
- base, source)); \
- INCR_MARKS(hhdr); \
- GC_STORE_BACK_PTR((ptr_t)source, base); \
- PUSH_OBJ(base, hhdr, mark_stack_top, mark_stack_limit); \
- }
- #endif /* MARK_BIT_PER_OBJ */
- #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.
- * Invoke FIXUP_POINTER(p) before any further processing.
- * 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.
- */
- # if NEED_FIXUP_POINTER
- /* Try both the raw version and the fixed up one. */
- # define GC_PUSH_ONE_STACK(p, source) \
- if ((p) >= (ptr_t)GC_least_plausible_heap_addr \
- && (p) < (ptr_t)GC_greatest_plausible_heap_addr) { \
- PUSH_ONE_CHECKED_STACK(p, source); \
- } \
- FIXUP_POINTER(p); \
- if ((p) >= (ptr_t)GC_least_plausible_heap_addr \
- && (p) < (ptr_t)GC_greatest_plausible_heap_addr) { \
- PUSH_ONE_CHECKED_STACK(p, source); \
- }
- # else /* !NEED_FIXUP_POINTER */
- # 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); \
- }
- # endif
- /*
- * As above, but interior pointer recognition as for
- * normal heap pointers.
- */
- # define GC_PUSH_ONE_HEAP(p,source) \
- FIXUP_POINTER(p); \
- if ((p) >= (ptr_t)GC_least_plausible_heap_addr \
- && (p) < (ptr_t)GC_greatest_plausible_heap_addr) { \
- GC_mark_stack_top = GC_mark_and_push( \
- (void *)(p), GC_mark_stack_top, \
- GC_mark_stack_limit, (void * *)(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(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.
- * Note that this is called with the mutator running, but
- * with us holding the allocation lock. This is safe only if the
- * mutator needs tha allocation lock to reveal hidden pointers.
- * FIXME: Why do we need the GC_mark_state test below?
- */
- # 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 */