X-Git-Url: http://wien.tomnetworks.com/gitweb/?p=hs-boehmgc.git;a=blobdiff_plain;f=gc-7.2%2Fallchblk.c;fp=gc-7.2%2Fallchblk.c;h=fe10b03a281b1f6bf1085b6cd24ef28667f47670;hp=0000000000000000000000000000000000000000;hb=324587ba93dc77f37406d41fd2a20d0e0d94fb1d;hpb=2a4ea609491b225a1ceb06da70396e93916f137a diff --git a/gc-7.2/allchblk.c b/gc-7.2/allchblk.c new file mode 100644 index 0000000..fe10b03 --- /dev/null +++ b/gc-7.2/allchblk.c @@ -0,0 +1,896 @@ +/* + * 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 + +#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); +}