--- /dev/null
+/*
+ * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
+ * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
+ * Copyright (c) 1998-1999 by Silicon Graphics. All rights reserved.
+ * Copyright (c) 1999 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_priv.h"
+
+#include <stdio.h>
+
+#ifdef GC_USE_ENTIRE_HEAP
+ int GC_use_entire_heap = TRUE;
+#else
+ int GC_use_entire_heap = FALSE;
+#endif
+
+/*
+ * Free heap blocks are kept on one of several free lists,
+ * depending on the size of the block. Each free list is doubly linked.
+ * Adjacent free blocks are coalesced.
+ */
+
+
+# define MAX_BLACK_LIST_ALLOC (2*HBLKSIZE)
+ /* largest block we will allocate starting on a black */
+ /* listed block. Must be >= HBLKSIZE. */
+
+
+# define UNIQUE_THRESHOLD 32
+ /* Sizes up to this many HBLKs each have their own free list */
+# define HUGE_THRESHOLD 256
+ /* Sizes of at least this many heap blocks are mapped to a */
+ /* single free list. */
+# define FL_COMPRESSION 8
+ /* In between sizes map this many distinct sizes to a single */
+ /* bin. */
+
+# define N_HBLK_FLS (HUGE_THRESHOLD - UNIQUE_THRESHOLD)/FL_COMPRESSION \
+ + UNIQUE_THRESHOLD
+
+#ifndef GC_GCJ_SUPPORT
+ STATIC
+#endif
+ struct hblk * GC_hblkfreelist[N_HBLK_FLS+1] = { 0 };
+ /* List of completely empty heap blocks */
+ /* Linked through hb_next field of */
+ /* header structure associated with */
+ /* block. Remains externally visible */
+ /* as used by GNU GCJ currently. */
+
+#ifndef USE_MUNMAP
+
+#ifndef GC_GCJ_SUPPORT
+ STATIC
+#endif
+ word GC_free_bytes[N_HBLK_FLS+1] = { 0 };
+ /* Number of free bytes on each list. Remains visible to GCJ. */
+
+ /* Return the largest n such that */
+ /* Is GC_large_allocd_bytes + the number of free bytes on lists */
+ /* n .. N_HBLK_FLS > GC_max_large_allocd_bytes. */
+ /* If there is no such n, return 0. */
+ GC_INLINE int GC_enough_large_bytes_left(void)
+ {
+ int n;
+ word bytes = GC_large_allocd_bytes;
+
+ GC_ASSERT(GC_max_large_allocd_bytes <= GC_heapsize);
+ for (n = N_HBLK_FLS; n >= 0; --n) {
+ bytes += GC_free_bytes[n];
+ if (bytes >= GC_max_large_allocd_bytes) return n;
+ }
+ return 0;
+ }
+
+# define INCR_FREE_BYTES(n, b) GC_free_bytes[n] += (b);
+
+# define FREE_ASSERT(e) GC_ASSERT(e)
+
+#else /* USE_MUNMAP */
+
+# define INCR_FREE_BYTES(n, b)
+# define FREE_ASSERT(e)
+
+#endif /* USE_MUNMAP */
+
+/* Map a number of blocks to the appropriate large block free list index. */
+STATIC int GC_hblk_fl_from_blocks(word blocks_needed)
+{
+ if (blocks_needed <= UNIQUE_THRESHOLD) return (int)blocks_needed;
+ if (blocks_needed >= HUGE_THRESHOLD) return N_HBLK_FLS;
+ return (int)(blocks_needed - UNIQUE_THRESHOLD)/FL_COMPRESSION
+ + UNIQUE_THRESHOLD;
+
+}
+
+# define PHDR(hhdr) HDR(hhdr -> hb_prev)
+# define NHDR(hhdr) HDR(hhdr -> hb_next)
+
+# ifdef USE_MUNMAP
+# define IS_MAPPED(hhdr) (((hhdr) -> hb_flags & WAS_UNMAPPED) == 0)
+# else /* !USE_MUNMAP */
+# define IS_MAPPED(hhdr) 1
+# endif /* USE_MUNMAP */
+
+# if !defined(NO_DEBUGGING)
+void GC_print_hblkfreelist(void)
+{
+ struct hblk * h;
+ word total_free = 0;
+ hdr * hhdr;
+ word sz;
+ unsigned i;
+
+ for (i = 0; i <= N_HBLK_FLS; ++i) {
+ h = GC_hblkfreelist[i];
+# ifdef USE_MUNMAP
+ if (0 != h) GC_printf("Free list %u:\n", i);
+# else
+ if (0 != h) GC_printf("Free list %u (total size %lu):\n",
+ i, (unsigned long)GC_free_bytes[i]);
+# endif
+ while (h != 0) {
+ hhdr = HDR(h);
+ sz = hhdr -> hb_sz;
+ total_free += sz;
+ GC_printf("\t%p size %lu %s black listed\n", h, (unsigned long)sz,
+ GC_is_black_listed(h, HBLKSIZE) != 0 ? "start" :
+ GC_is_black_listed(h, hhdr -> hb_sz) != 0 ? "partially" :
+ "not");
+ h = hhdr -> hb_next;
+ }
+ }
+# ifndef USE_MUNMAP
+ if (total_free != GC_large_free_bytes) {
+ GC_printf("GC_large_free_bytes = %lu (INCONSISTENT!!)\n",
+ (unsigned long) GC_large_free_bytes);
+ }
+# endif
+ GC_printf("Total of %lu bytes on free list\n", (unsigned long)total_free);
+}
+
+/* Return the free list index on which the block described by the header */
+/* appears, or -1 if it appears nowhere. */
+static int free_list_index_of(hdr *wanted)
+{
+ struct hblk * h;
+ hdr * hhdr;
+ int i;
+
+ for (i = 0; i <= N_HBLK_FLS; ++i) {
+ h = GC_hblkfreelist[i];
+ while (h != 0) {
+ hhdr = HDR(h);
+ if (hhdr == wanted) return i;
+ h = hhdr -> hb_next;
+ }
+ }
+ return -1;
+}
+
+void GC_dump_regions(void)
+{
+ unsigned i;
+ ptr_t start, end;
+ ptr_t p;
+ size_t bytes;
+ hdr *hhdr;
+ for (i = 0; i < GC_n_heap_sects; ++i) {
+ start = GC_heap_sects[i].hs_start;
+ bytes = GC_heap_sects[i].hs_bytes;
+ end = start + bytes;
+ /* Merge in contiguous sections. */
+ while (i+1 < GC_n_heap_sects && GC_heap_sects[i+1].hs_start == end) {
+ ++i;
+ end = GC_heap_sects[i].hs_start + GC_heap_sects[i].hs_bytes;
+ }
+ GC_printf("***Section from %p to %p\n", start, end);
+ for (p = start; p < end;) {
+ hhdr = HDR(p);
+ if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
+ GC_printf("\t%p Missing header!!(%p)\n", p, hhdr);
+ p += HBLKSIZE;
+ continue;
+ }
+ if (HBLK_IS_FREE(hhdr)) {
+ int correct_index = GC_hblk_fl_from_blocks(
+ divHBLKSZ(hhdr -> hb_sz));
+ int actual_index;
+
+ GC_printf("\t%p\tfree block of size 0x%lx bytes%s\n", p,
+ (unsigned long)(hhdr -> hb_sz),
+ IS_MAPPED(hhdr) ? "" : " (unmapped)");
+ actual_index = free_list_index_of(hhdr);
+ if (-1 == actual_index) {
+ GC_printf("\t\tBlock not on free list %d!!\n",
+ correct_index);
+ } else if (correct_index != actual_index) {
+ GC_printf("\t\tBlock on list %d, should be on %d!!\n",
+ actual_index, correct_index);
+ }
+ p += hhdr -> hb_sz;
+ } else {
+ GC_printf("\t%p\tused for blocks of size 0x%lx bytes\n", p,
+ (unsigned long)(hhdr -> hb_sz));
+ p += HBLKSIZE * OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
+ }
+ }
+ }
+}
+
+# endif /* NO_DEBUGGING */
+
+/* Initialize hdr for a block containing the indicated size and */
+/* kind of objects. */
+/* Return FALSE on failure. */
+static GC_bool setup_header(hdr * hhdr, struct hblk *block, size_t byte_sz,
+ int kind, unsigned flags)
+{
+ word descr;
+# ifndef MARK_BIT_PER_OBJ
+ size_t granules;
+# endif
+
+ /* Set size, kind and mark proc fields */
+ hhdr -> hb_sz = byte_sz;
+ hhdr -> hb_obj_kind = (unsigned char)kind;
+ hhdr -> hb_flags = (unsigned char)flags;
+ hhdr -> hb_block = block;
+ descr = GC_obj_kinds[kind].ok_descriptor;
+ if (GC_obj_kinds[kind].ok_relocate_descr) descr += byte_sz;
+ hhdr -> hb_descr = descr;
+
+# ifdef MARK_BIT_PER_OBJ
+ /* Set hb_inv_sz as portably as possible. */
+ /* We set it to the smallest value such that sz * inv_sz > 2**32 */
+ /* This may be more precision than necessary. */
+ if (byte_sz > MAXOBJBYTES) {
+ hhdr -> hb_inv_sz = LARGE_INV_SZ;
+ } else {
+ word inv_sz;
+
+# if CPP_WORDSZ == 64
+ inv_sz = ((word)1 << 32)/byte_sz;
+ if (((inv_sz*byte_sz) >> 32) == 0) ++inv_sz;
+# else /* 32 bit words */
+ GC_ASSERT(byte_sz >= 4);
+ inv_sz = ((unsigned)1 << 31)/byte_sz;
+ inv_sz *= 2;
+ while (inv_sz*byte_sz > byte_sz) ++inv_sz;
+# endif
+ hhdr -> hb_inv_sz = inv_sz;
+ }
+# else /* MARK_BIT_PER_GRANULE */
+ hhdr -> hb_large_block = (unsigned char)(byte_sz > MAXOBJBYTES);
+ granules = BYTES_TO_GRANULES(byte_sz);
+ if (EXPECT(!GC_add_map_entry(granules), FALSE)) {
+ /* Make it look like a valid block. */
+ hhdr -> hb_sz = HBLKSIZE;
+ hhdr -> hb_descr = 0;
+ hhdr -> hb_large_block = TRUE;
+ hhdr -> hb_map = 0;
+ return FALSE;
+ } else {
+ size_t index = (hhdr -> hb_large_block? 0 : granules);
+ hhdr -> hb_map = GC_obj_map[index];
+ }
+# endif /* MARK_BIT_PER_GRANULE */
+
+ /* Clear mark bits */
+ GC_clear_hdr_marks(hhdr);
+
+ hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
+ return(TRUE);
+}
+
+#define FL_UNKNOWN -1
+/*
+ * Remove hhdr from the appropriate free list.
+ * We assume it is on the nth free list, or on the size
+ * appropriate free list if n is FL_UNKNOWN.
+ */
+STATIC void GC_remove_from_fl(hdr *hhdr, int n)
+{
+ int index;
+
+ GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0);
+# ifndef USE_MUNMAP
+ /* We always need index to maintain free counts. */
+ if (FL_UNKNOWN == n) {
+ index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz));
+ } else {
+ index = n;
+ }
+# endif
+ if (hhdr -> hb_prev == 0) {
+# ifdef USE_MUNMAP
+ if (FL_UNKNOWN == n) {
+ index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz));
+ } else {
+ index = n;
+ }
+# endif
+ GC_ASSERT(HDR(GC_hblkfreelist[index]) == hhdr);
+ GC_hblkfreelist[index] = hhdr -> hb_next;
+ } else {
+ hdr *phdr;
+ GET_HDR(hhdr -> hb_prev, phdr);
+ phdr -> hb_next = hhdr -> hb_next;
+ }
+ FREE_ASSERT(GC_free_bytes[index] >= hhdr -> hb_sz);
+ INCR_FREE_BYTES(index, - (signed_word)(hhdr -> hb_sz));
+ if (0 != hhdr -> hb_next) {
+ hdr * nhdr;
+ GC_ASSERT(!IS_FORWARDING_ADDR_OR_NIL(NHDR(hhdr)));
+ GET_HDR(hhdr -> hb_next, nhdr);
+ nhdr -> hb_prev = hhdr -> hb_prev;
+ }
+}
+
+/*
+ * Return a pointer to the free block ending just before h, if any.
+ */
+STATIC struct hblk * GC_free_block_ending_at(struct hblk *h)
+{
+ struct hblk * p = h - 1;
+ hdr * phdr;
+
+ GET_HDR(p, phdr);
+ while (0 != phdr && IS_FORWARDING_ADDR_OR_NIL(phdr)) {
+ p = FORWARDED_ADDR(p,phdr);
+ phdr = HDR(p);
+ }
+ if (0 != phdr) {
+ if(HBLK_IS_FREE(phdr)) {
+ return p;
+ } else {
+ return 0;
+ }
+ }
+ p = GC_prev_block(h - 1);
+ if (0 != p) {
+ phdr = HDR(p);
+ if (HBLK_IS_FREE(phdr) && (ptr_t)p + phdr -> hb_sz == (ptr_t)h) {
+ return p;
+ }
+ }
+ return 0;
+}
+
+/*
+ * Add hhdr to the appropriate free list.
+ * We maintain individual free lists sorted by address.
+ */
+STATIC void GC_add_to_fl(struct hblk *h, hdr *hhdr)
+{
+ int index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz));
+ struct hblk *second = GC_hblkfreelist[index];
+ hdr * second_hdr;
+# if defined(GC_ASSERTIONS) && !defined(USE_MUNMAP)
+ struct hblk *next = (struct hblk *)((word)h + hhdr -> hb_sz);
+ hdr * nexthdr = HDR(next);
+ struct hblk *prev = GC_free_block_ending_at(h);
+ hdr * prevhdr = HDR(prev);
+ GC_ASSERT(nexthdr == 0 || !HBLK_IS_FREE(nexthdr)
+ || (signed_word)GC_heapsize < 0);
+ /* In the last case, blocks may be too large to merge. */
+ GC_ASSERT(prev == 0 || !HBLK_IS_FREE(prevhdr)
+ || (signed_word)GC_heapsize < 0);
+# endif
+ GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0);
+ GC_hblkfreelist[index] = h;
+ INCR_FREE_BYTES(index, hhdr -> hb_sz);
+ FREE_ASSERT(GC_free_bytes[index] <= GC_large_free_bytes);
+ hhdr -> hb_next = second;
+ hhdr -> hb_prev = 0;
+ if (0 != second) {
+ GET_HDR(second, second_hdr);
+ second_hdr -> hb_prev = h;
+ }
+ hhdr -> hb_flags |= FREE_BLK;
+}
+
+#ifdef USE_MUNMAP
+
+# ifndef MUNMAP_THRESHOLD
+# define MUNMAP_THRESHOLD 6
+# endif
+
+GC_INNER int GC_unmap_threshold = MUNMAP_THRESHOLD;
+
+/* Unmap blocks that haven't been recently touched. This is the only way */
+/* way blocks are ever unmapped. */
+GC_INNER void GC_unmap_old(void)
+{
+ struct hblk * h;
+ hdr * hhdr;
+ int i;
+
+ if (GC_unmap_threshold == 0)
+ return; /* unmapping disabled */
+
+ for (i = 0; i <= N_HBLK_FLS; ++i) {
+ for (h = GC_hblkfreelist[i]; 0 != h; h = hhdr -> hb_next) {
+ hhdr = HDR(h);
+ if (!IS_MAPPED(hhdr)) continue;
+
+ if ((unsigned short)GC_gc_no - hhdr -> hb_last_reclaimed >
+ (unsigned short)GC_unmap_threshold) {
+ GC_unmap((ptr_t)h, hhdr -> hb_sz);
+ hhdr -> hb_flags |= WAS_UNMAPPED;
+ }
+ }
+ }
+}
+
+/* Merge all unmapped blocks that are adjacent to other free */
+/* blocks. This may involve remapping, since all blocks are either */
+/* fully mapped or fully unmapped. */
+GC_INNER void GC_merge_unmapped(void)
+{
+ struct hblk * h, *next;
+ hdr * hhdr, *nexthdr;
+ word size, nextsize;
+ int i;
+
+ for (i = 0; i <= N_HBLK_FLS; ++i) {
+ h = GC_hblkfreelist[i];
+ while (h != 0) {
+ GET_HDR(h, hhdr);
+ size = hhdr->hb_sz;
+ next = (struct hblk *)((word)h + size);
+ GET_HDR(next, nexthdr);
+ /* Coalesce with successor, if possible */
+ if (0 != nexthdr && HBLK_IS_FREE(nexthdr)
+ && (signed_word) (size + (nextsize = nexthdr->hb_sz)) > 0
+ /* no pot. overflow */) {
+ /* Note that we usually try to avoid adjacent free blocks */
+ /* that are either both mapped or both unmapped. But that */
+ /* isn't guaranteed to hold since we remap blocks when we */
+ /* split them, and don't merge at that point. It may also */
+ /* not hold if the merged block would be too big. */
+ if (IS_MAPPED(hhdr) && !IS_MAPPED(nexthdr)) {
+ /* make both consistent, so that we can merge */
+ if (size > nextsize) {
+ GC_remap((ptr_t)next, nextsize);
+ } else {
+ GC_unmap((ptr_t)h, size);
+ GC_unmap_gap((ptr_t)h, size, (ptr_t)next, nextsize);
+ hhdr -> hb_flags |= WAS_UNMAPPED;
+ }
+ } else if (IS_MAPPED(nexthdr) && !IS_MAPPED(hhdr)) {
+ if (size > nextsize) {
+ GC_unmap((ptr_t)next, nextsize);
+ GC_unmap_gap((ptr_t)h, size, (ptr_t)next, nextsize);
+ } else {
+ GC_remap((ptr_t)h, size);
+ hhdr -> hb_flags &= ~WAS_UNMAPPED;
+ hhdr -> hb_last_reclaimed = nexthdr -> hb_last_reclaimed;
+ }
+ } else if (!IS_MAPPED(hhdr) && !IS_MAPPED(nexthdr)) {
+ /* Unmap any gap in the middle */
+ GC_unmap_gap((ptr_t)h, size, (ptr_t)next, nextsize);
+ }
+ /* If they are both unmapped, we merge, but leave unmapped. */
+ GC_remove_from_fl(hhdr, i);
+ GC_remove_from_fl(nexthdr, FL_UNKNOWN);
+ hhdr -> hb_sz += nexthdr -> hb_sz;
+ GC_remove_header(next);
+ GC_add_to_fl(h, hhdr);
+ /* Start over at beginning of list */
+ h = GC_hblkfreelist[i];
+ } else /* not mergable with successor */ {
+ h = hhdr -> hb_next;
+ }
+ } /* while (h != 0) ... */
+ } /* for ... */
+}
+
+#endif /* USE_MUNMAP */
+
+/*
+ * Return a pointer to a block starting at h of length bytes.
+ * Memory for the block is mapped.
+ * Remove the block from its free list, and return the remainder (if any)
+ * to its appropriate free list.
+ * May fail by returning 0.
+ * The header for the returned block must be set up by the caller.
+ * If the return value is not 0, then hhdr is the header for it.
+ */
+STATIC struct hblk * GC_get_first_part(struct hblk *h, hdr *hhdr,
+ size_t bytes, int index)
+{
+ word total_size = hhdr -> hb_sz;
+ struct hblk * rest;
+ hdr * rest_hdr;
+
+ GC_ASSERT((total_size & (HBLKSIZE-1)) == 0);
+ GC_remove_from_fl(hhdr, index);
+ if (total_size == bytes) return h;
+ rest = (struct hblk *)((word)h + bytes);
+ rest_hdr = GC_install_header(rest);
+ if (0 == rest_hdr) {
+ /* FIXME: This is likely to be very bad news ... */
+ WARN("Header allocation failed: Dropping block.\n", 0);
+ return(0);
+ }
+ rest_hdr -> hb_sz = total_size - bytes;
+ rest_hdr -> hb_flags = 0;
+# ifdef GC_ASSERTIONS
+ /* Mark h not free, to avoid assertion about adjacent free blocks. */
+ hhdr -> hb_flags &= ~FREE_BLK;
+# endif
+ GC_add_to_fl(rest, rest_hdr);
+ return h;
+}
+
+/*
+ * H is a free block. N points at an address inside it.
+ * A new header for n has already been set up. Fix up h's header
+ * to reflect the fact that it is being split, move it to the
+ * appropriate free list.
+ * N replaces h in the original free list.
+ *
+ * Nhdr is not completely filled in, since it is about to allocated.
+ * It may in fact end up on the wrong free list for its size.
+ * That's not a disaster, since n is about to be allocated
+ * by our caller.
+ * (Hence adding it to a free list is silly. But this path is hopefully
+ * rare enough that it doesn't matter. The code is cleaner this way.)
+ */
+STATIC void GC_split_block(struct hblk *h, hdr *hhdr, struct hblk *n,
+ hdr *nhdr, int index /* Index of free list */)
+{
+ word total_size = hhdr -> hb_sz;
+ word h_size = (word)n - (word)h;
+ struct hblk *prev = hhdr -> hb_prev;
+ struct hblk *next = hhdr -> hb_next;
+
+ /* Replace h with n on its freelist */
+ nhdr -> hb_prev = prev;
+ nhdr -> hb_next = next;
+ nhdr -> hb_sz = total_size - h_size;
+ nhdr -> hb_flags = 0;
+ if (0 != prev) {
+ HDR(prev) -> hb_next = n;
+ } else {
+ GC_hblkfreelist[index] = n;
+ }
+ if (0 != next) {
+ HDR(next) -> hb_prev = n;
+ }
+ INCR_FREE_BYTES(index, -(signed_word)h_size);
+ FREE_ASSERT(GC_free_bytes[index] > 0);
+# ifdef USE_MUNMAP
+ hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
+# endif
+ hhdr -> hb_sz = h_size;
+ GC_add_to_fl(h, hhdr);
+ nhdr -> hb_flags |= FREE_BLK;
+}
+
+STATIC struct hblk *
+GC_allochblk_nth(size_t sz/* bytes */, int kind, unsigned flags, int n,
+ GC_bool may_split);
+
+/*
+ * Allocate (and return pointer to) a heap block
+ * for objects of size sz bytes, searching the nth free list.
+ *
+ * NOTE: We set obj_map field in header correctly.
+ * Caller is responsible for building an object freelist in block.
+ *
+ * The client is responsible for clearing the block, if necessary.
+ */
+GC_INNER struct hblk *
+GC_allochblk(size_t sz, int kind, unsigned flags/* IGNORE_OFF_PAGE or 0 */)
+{
+ word blocks;
+ int start_list;
+ int i;
+ struct hblk *result;
+ int split_limit; /* Highest index of free list whose blocks we */
+ /* split. */
+
+ GC_ASSERT((sz & (GRANULE_BYTES - 1)) == 0);
+ blocks = OBJ_SZ_TO_BLOCKS(sz);
+ if ((signed_word)(blocks * HBLKSIZE) < 0) {
+ return 0;
+ }
+ start_list = GC_hblk_fl_from_blocks(blocks);
+ /* Try for an exact match first. */
+ result = GC_allochblk_nth(sz, kind, flags, start_list, FALSE);
+ if (0 != result) return result;
+ if (GC_use_entire_heap || GC_dont_gc
+ || USED_HEAP_SIZE < GC_requested_heapsize
+ || GC_incremental || !GC_should_collect()) {
+ /* Should use more of the heap, even if it requires splitting. */
+ split_limit = N_HBLK_FLS;
+ } else {
+# ifdef USE_MUNMAP
+ /* avoid splitting, since that might require remapping */
+ split_limit = 0;
+# else
+ if (GC_finalizer_bytes_freed > (GC_heapsize >> 4)) {
+ /* If we are deallocating lots of memory from */
+ /* finalizers, fail and collect sooner rather */
+ /* than later. */
+ split_limit = 0;
+ } else {
+ /* If we have enough large blocks left to cover any */
+ /* previous request for large blocks, we go ahead */
+ /* and split. Assuming a steady state, that should */
+ /* be safe. It means that we can use the full */
+ /* heap if we allocate only small objects. */
+ split_limit = GC_enough_large_bytes_left();
+ }
+# endif
+ }
+ if (start_list < UNIQUE_THRESHOLD) {
+ /* No reason to try start_list again, since all blocks are exact */
+ /* matches. */
+ ++start_list;
+ }
+ for (i = start_list; i <= split_limit; ++i) {
+ struct hblk * result = GC_allochblk_nth(sz, kind, flags, i, TRUE);
+ if (0 != result) return result;
+ }
+ return 0;
+}
+
+STATIC long GC_large_alloc_warn_suppressed = 0;
+ /* Number of warnings suppressed so far. */
+
+/*
+ * The same, but with search restricted to nth free list.
+ * Flags is IGNORE_OFF_PAGE or zero.
+ * Unlike the above, sz is in bytes.
+ * The may_split flag indicates whether it's OK to split larger blocks.
+ */
+STATIC struct hblk *
+GC_allochblk_nth(size_t sz, int kind, unsigned flags, int n,
+ GC_bool may_split)
+{
+ struct hblk *hbp;
+ hdr * hhdr; /* Header corr. to hbp */
+ /* Initialized after loop if hbp !=0 */
+ /* Gcc uninitialized use warning is bogus. */
+ struct hblk *thishbp;
+ hdr * thishdr; /* Header corr. to hbp */
+ signed_word size_needed; /* number of bytes in requested objects */
+ signed_word size_avail; /* bytes available in this block */
+
+ size_needed = HBLKSIZE * OBJ_SZ_TO_BLOCKS(sz);
+
+ /* search for a big enough block in free list */
+ hbp = GC_hblkfreelist[n];
+ for(; 0 != hbp; hbp = hhdr -> hb_next) {
+ GET_HDR(hbp, hhdr);
+ size_avail = hhdr->hb_sz;
+ if (size_avail < size_needed) continue;
+ if (size_avail != size_needed) {
+ signed_word next_size;
+
+ if (!may_split) continue;
+ /* If the next heap block is obviously better, go on. */
+ /* This prevents us from disassembling a single large block */
+ /* to get tiny blocks. */
+ thishbp = hhdr -> hb_next;
+ if (thishbp != 0) {
+ GET_HDR(thishbp, thishdr);
+ next_size = (signed_word)(thishdr -> hb_sz);
+ if (next_size < size_avail
+ && next_size >= size_needed
+ && !GC_is_black_listed(thishbp, (word)size_needed)) {
+ continue;
+ }
+ }
+ }
+ if ( !IS_UNCOLLECTABLE(kind) && (kind != PTRFREE
+ || size_needed > (signed_word)MAX_BLACK_LIST_ALLOC)) {
+ struct hblk * lasthbp = hbp;
+ ptr_t search_end = (ptr_t)hbp + size_avail - size_needed;
+ signed_word orig_avail = size_avail;
+ signed_word eff_size_needed = (flags & IGNORE_OFF_PAGE) != 0 ?
+ (signed_word)HBLKSIZE
+ : size_needed;
+
+
+ while ((ptr_t)lasthbp <= search_end
+ && (thishbp = GC_is_black_listed(lasthbp,
+ (word)eff_size_needed))
+ != 0) {
+ lasthbp = thishbp;
+ }
+ size_avail -= (ptr_t)lasthbp - (ptr_t)hbp;
+ thishbp = lasthbp;
+ if (size_avail >= size_needed) {
+ if (thishbp != hbp &&
+ 0 != (thishdr = GC_install_header(thishbp))) {
+ /* Make sure it's mapped before we mangle it. */
+# ifdef USE_MUNMAP
+ if (!IS_MAPPED(hhdr)) {
+ GC_remap((ptr_t)hbp, hhdr -> hb_sz);
+ hhdr -> hb_flags &= ~WAS_UNMAPPED;
+ }
+# endif
+ /* Split the block at thishbp */
+ GC_split_block(hbp, hhdr, thishbp, thishdr, n);
+ /* Advance to thishbp */
+ hbp = thishbp;
+ hhdr = thishdr;
+ /* We must now allocate thishbp, since it may */
+ /* be on the wrong free list. */
+ }
+ } else if (size_needed > (signed_word)BL_LIMIT
+ && orig_avail - size_needed
+ > (signed_word)BL_LIMIT) {
+ /* Punt, since anything else risks unreasonable heap growth. */
+ if (++GC_large_alloc_warn_suppressed
+ >= GC_large_alloc_warn_interval) {
+ WARN("Repeated allocation of very large block "
+ "(appr. size %" GC_PRIdPTR "):\n"
+ "\tMay lead to memory leak and poor performance.\n",
+ size_needed);
+ GC_large_alloc_warn_suppressed = 0;
+ }
+ size_avail = orig_avail;
+ } else if (size_avail == 0 && size_needed == HBLKSIZE
+ && IS_MAPPED(hhdr)) {
+ if (!GC_find_leak) {
+ static unsigned count = 0;
+
+ /* The block is completely blacklisted. We need */
+ /* to drop some such blocks, since otherwise we spend */
+ /* all our time traversing them if pointerfree */
+ /* blocks are unpopular. */
+ /* A dropped block will be reconsidered at next GC. */
+ if ((++count & 3) == 0) {
+ /* Allocate and drop the block in small chunks, to */
+ /* maximize the chance that we will recover some */
+ /* later. */
+ word total_size = hhdr -> hb_sz;
+ struct hblk * limit = hbp + divHBLKSZ(total_size);
+ struct hblk * h;
+ struct hblk * prev = hhdr -> hb_prev;
+
+ GC_large_free_bytes -= total_size;
+ GC_bytes_dropped += total_size;
+ GC_remove_from_fl(hhdr, n);
+ for (h = hbp; h < limit; h++) {
+ if (h == hbp || 0 != (hhdr = GC_install_header(h))) {
+ (void) setup_header(
+ hhdr, h,
+ HBLKSIZE,
+ PTRFREE, 0); /* Can't fail */
+ if (GC_debugging_started) {
+ BZERO(h, HBLKSIZE);
+ }
+ }
+ }
+ /* Restore hbp to point at free block */
+ hbp = prev;
+ if (0 == hbp) {
+ return GC_allochblk_nth(sz, kind, flags, n, may_split);
+ }
+ hhdr = HDR(hbp);
+ }
+ }
+ }
+ }
+ if( size_avail >= size_needed ) {
+# ifdef USE_MUNMAP
+ if (!IS_MAPPED(hhdr)) {
+ GC_remap((ptr_t)hbp, hhdr -> hb_sz);
+ hhdr -> hb_flags &= ~WAS_UNMAPPED;
+ /* Note: This may leave adjacent, mapped free blocks. */
+ }
+# endif
+ /* hbp may be on the wrong freelist; the parameter n */
+ /* is important. */
+ hbp = GC_get_first_part(hbp, hhdr, size_needed, n);
+ break;
+ }
+ }
+
+ if (0 == hbp) return 0;
+
+ /* Add it to map of valid blocks */
+ if (!GC_install_counts(hbp, (word)size_needed)) return(0);
+ /* This leaks memory under very rare conditions. */
+
+ /* Set up header */
+ if (!setup_header(hhdr, hbp, sz, kind, flags)) {
+ GC_remove_counts(hbp, (word)size_needed);
+ return(0); /* ditto */
+ }
+# ifndef GC_DISABLE_INCREMENTAL
+ /* Notify virtual dirty bit implementation that we are about to */
+ /* write. Ensure that pointerfree objects are not protected if */
+ /* it's avoidable. This also ensures that newly allocated */
+ /* blocks are treated as dirty. Necessary since we don't */
+ /* protect free blocks. */
+ GC_ASSERT((size_needed & (HBLKSIZE-1)) == 0);
+ GC_remove_protection(hbp, divHBLKSZ(size_needed),
+ (hhdr -> hb_descr == 0) /* pointer-free */);
+# endif
+ /* We just successfully allocated a block. Restart count of */
+ /* consecutive failures. */
+ GC_fail_count = 0;
+
+ GC_large_free_bytes -= size_needed;
+
+ GC_ASSERT(IS_MAPPED(hhdr));
+ return( hbp );
+}
+
+/*
+ * Free a heap block.
+ *
+ * Coalesce the block with its neighbors if possible.
+ *
+ * All mark words are assumed to be cleared.
+ */
+GC_INNER void GC_freehblk(struct hblk *hbp)
+{
+ struct hblk *next, *prev;
+ hdr *hhdr, *prevhdr, *nexthdr;
+ signed_word size;
+
+ GET_HDR(hbp, hhdr);
+ size = hhdr->hb_sz;
+ size = HBLKSIZE * OBJ_SZ_TO_BLOCKS(size);
+ if (size <= 0)
+ ABORT("Deallocating excessively large block. Too large an allocation?");
+ /* Probably possible if we try to allocate more than half the address */
+ /* space at once. If we don't catch it here, strange things happen */
+ /* later. */
+ GC_remove_counts(hbp, (word)size);
+ hhdr->hb_sz = size;
+# ifdef USE_MUNMAP
+ hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
+# endif
+
+ /* Check for duplicate deallocation in the easy case */
+ if (HBLK_IS_FREE(hhdr)) {
+ if (GC_print_stats)
+ GC_log_printf("Duplicate large block deallocation of %p\n", hbp);
+ ABORT("Duplicate large block deallocation");
+ }
+
+ GC_ASSERT(IS_MAPPED(hhdr));
+ hhdr -> hb_flags |= FREE_BLK;
+ next = (struct hblk *)((word)hbp + size);
+ GET_HDR(next, nexthdr);
+ prev = GC_free_block_ending_at(hbp);
+ /* Coalesce with successor, if possible */
+ if(0 != nexthdr && HBLK_IS_FREE(nexthdr) && IS_MAPPED(nexthdr)
+ && (signed_word)(hhdr -> hb_sz + nexthdr -> hb_sz) > 0
+ /* no overflow */) {
+ GC_remove_from_fl(nexthdr, FL_UNKNOWN);
+ hhdr -> hb_sz += nexthdr -> hb_sz;
+ GC_remove_header(next);
+ }
+ /* Coalesce with predecessor, if possible. */
+ if (0 != prev) {
+ prevhdr = HDR(prev);
+ if (IS_MAPPED(prevhdr)
+ && (signed_word)(hhdr -> hb_sz + prevhdr -> hb_sz) > 0) {
+ GC_remove_from_fl(prevhdr, FL_UNKNOWN);
+ prevhdr -> hb_sz += hhdr -> hb_sz;
+# ifdef USE_MUNMAP
+ prevhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
+# endif
+ GC_remove_header(hbp);
+ hbp = prev;
+ hhdr = prevhdr;
+ }
+ }
+ /* FIXME: It is not clear we really always want to do these merges */
+ /* with USE_MUNMAP, since it updates ages and hence prevents */
+ /* unmapping. */
+
+ GC_large_free_bytes += size;
+ GC_add_to_fl(hbp, hhdr);
+}
projects / hs-boehmgc.git / blobdiff