diff options
Diffstat (limited to 'contrib/gcc/ggc-page.c')
| -rw-r--r-- | contrib/gcc/ggc-page.c | 521 |
1 files changed, 409 insertions, 112 deletions
diff --git a/contrib/gcc/ggc-page.c b/contrib/gcc/ggc-page.c index ad3f815..3f5194a 100644 --- a/contrib/gcc/ggc-page.c +++ b/contrib/gcc/ggc-page.c @@ -24,10 +24,16 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA #include "rtl.h" #include "tm_p.h" #include "toplev.h" -#include "varray.h" #include "flags.h" #include "ggc.h" #include "timevar.h" +#include "params.h" +#ifdef ENABLE_VALGRIND_CHECKING +#include <valgrind.h> +#else +/* Avoid #ifdef:s when we can help it. */ +#define VALGRIND_DISCARD(x) +#endif /* Prefer MAP_ANON(YMOUS) to /dev/zero, since we don't need to keep a file open. Prefer either to valloc. */ @@ -59,7 +65,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA #define USING_MALLOC_PAGE_GROUPS #endif -/* Stategy: +/* Stategy: This garbage-collecting allocator allocates objects on one of a set of pages. Each page can allocate objects of a single size only; @@ -74,7 +80,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA Each page-entry also has a context depth, which is used to track pushing and popping of allocation contexts. Only objects allocated - in the current (highest-numbered) context may be collected. + in the current (highest-numbered) context may be collected. Page entries are arranged in an array of singly-linked lists. The array is indexed by the allocation size, in bits, of the pages on @@ -88,23 +94,6 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA deallocated at the start of the next collection if they haven't been recycled by then. */ - -/* Define GGC_POISON to poison memory marked unused by the collector. */ -#undef GGC_POISON - -/* Define GGC_ALWAYS_COLLECT to perform collection every time - ggc_collect is invoked. Otherwise, collection is performed only - when a significant amount of memory has been allocated since the - last collection. */ -#undef GGC_ALWAYS_COLLECT - -#ifdef ENABLE_GC_CHECKING -#define GGC_POISON -#endif -#ifdef ENABLE_GC_ALWAYS_COLLECT -#define GGC_ALWAYS_COLLECT -#endif - /* Define GGC_DEBUG_LEVEL to print debugging information. 0: No debugging output. 1: GC statistics only. @@ -133,7 +122,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA The bottommost HOST_PAGE_SIZE_BITS are ignored, since page-entry pages are aligned on system page boundaries. The next most significant PAGE_L2_BITS and PAGE_L1_BITS are the second and first - index values in the lookup table, respectively. + index values in the lookup table, respectively. For 32-bit architectures and the settings below, there are no leftover bits. For architectures with wider pointers, the lookup @@ -158,11 +147,22 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA /* The size of an object on a page of the indicated ORDER. */ #define OBJECT_SIZE(ORDER) object_size_table[ORDER] +/* For speed, we avoid doing a general integer divide to locate the + offset in the allocation bitmap, by precalculating numbers M, S + such that (O * M) >> S == O / Z (modulo 2^32), for any offset O + within the page which is evenly divisible by the object size Z. */ +#define DIV_MULT(ORDER) inverse_table[ORDER].mult +#define DIV_SHIFT(ORDER) inverse_table[ORDER].shift +#define OFFSET_TO_BIT(OFFSET, ORDER) \ + (((OFFSET) * DIV_MULT (ORDER)) >> DIV_SHIFT (ORDER)) + /* The number of extra orders, not corresponding to power-of-two sized objects. */ -#define NUM_EXTRA_ORDERS \ - (sizeof (extra_order_size_table) / sizeof (extra_order_size_table[0])) +#define NUM_EXTRA_ORDERS ARRAY_SIZE (extra_order_size_table) + +#define RTL_SIZE(NSLOTS) \ + (sizeof (struct rtx_def) + ((NSLOTS) - 1) * sizeof (rtunion)) /* The Ith entry is the maximum size of an object to be stored in the Ith extra order. Adding a new entry to this array is the *only* @@ -170,7 +170,9 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA static const size_t extra_order_size_table[] = { sizeof (struct tree_decl), - sizeof (struct tree_list) + sizeof (struct tree_list), + RTL_SIZE (2), /* REG, MEM, PLUS, etc. */ + RTL_SIZE (10), /* INSN, CALL_INSN, JUMP_INSN */ }; /* The total number of orders. */ @@ -205,9 +207,20 @@ static unsigned objects_per_page_table[NUM_ORDERS]; static size_t object_size_table[NUM_ORDERS]; +/* The Ith entry is a pair of numbers (mult, shift) such that + ((k * mult) >> shift) mod 2^32 == (k / OBJECT_SIZE(I)) mod 2^32, + for all k evenly divisible by OBJECT_SIZE(I). */ + +static struct +{ + unsigned int mult; + unsigned int shift; +} +inverse_table[NUM_ORDERS]; + /* A page_entry records the status of an allocation page. This structure is dynamically sized to fit the bitmap in_use_p. */ -typedef struct page_entry +typedef struct page_entry { /* The next page-entry with objects of the same size, or NULL if this is the last page-entry. */ @@ -225,9 +238,9 @@ typedef struct page_entry struct page_group *group; #endif - /* Saved in-use bit vector for pages that aren't in the topmost - context during collection. */ - unsigned long *save_in_use_p; + /* This is the index in the by_depth varray where this page table + can be found. */ + unsigned long index_by_depth; /* Context depth of this page. */ unsigned short context_depth; @@ -316,6 +329,12 @@ static struct globals /* Total amount of memory mapped. */ size_t bytes_mapped; + /* Bit N set if any allocations have been done at context depth N. */ + unsigned long context_depth_allocations; + + /* Bit N set if any collections have been done at context depth N. */ + unsigned long context_depth_collections; + /* The current depth in the context stack. */ unsigned short context_depth; @@ -333,6 +352,36 @@ static struct globals /* The file descriptor for debugging output. */ FILE *debug_file; + + /* Current number of elements in use in depth below. */ + unsigned int depth_in_use; + + /* Maximum number of elements that can be used before resizing. */ + unsigned int depth_max; + + /* Each element of this arry is an index in by_depth where the given + depth starts. This structure is indexed by that given depth we + are interested in. */ + unsigned int *depth; + + /* Current number of elements in use in by_depth below. */ + unsigned int by_depth_in_use; + + /* Maximum number of elements that can be used before resizing. */ + unsigned int by_depth_max; + + /* Each element of this array is a pointer to a page_entry, all + page_entries can be found in here by increasing depth. + index_by_depth in the page_entry is the index into this data + structure where that page_entry can be found. This is used to + speed up finding all page_entries at a particular depth. */ + page_entry **by_depth; + + /* Each element is a pointer to the saved in_use_p bits, if any, + zero otherwise. We allocate them all together, to enable a + better runtime data access pattern. */ + unsigned long **save_in_use; + } G; /* The size in bytes required to maintain a bitmap for the objects @@ -340,21 +389,14 @@ static struct globals #define BITMAP_SIZE(Num_objects) \ (CEIL ((Num_objects), HOST_BITS_PER_LONG) * sizeof(long)) -/* Skip garbage collection if the current allocation is not at least - this factor times the allocation at the end of the last collection. - In other words, total allocation must expand by (this factor minus - one) before collection is performed. */ -#define GGC_MIN_EXPAND_FOR_GC (1.3) - -/* Bound `allocated_last_gc' to 4MB, to prevent the memory expansion - test from triggering too often when the heap is small. */ -#define GGC_MIN_LAST_ALLOCATED (4 * 1024 * 1024) - /* Allocate pages in chunks of this size, to throttle calls to memory allocation routines. The first page is used, the rest go onto the free list. This cannot be larger than HOST_BITS_PER_INT for the in_use bitmask for page_group. */ #define GGC_QUIRE_SIZE 16 + +/* Initial guess as to how many page table entries we might need. */ +#define INITIAL_PTE_COUNT 128 static int ggc_allocated_p PARAMS ((const void *)); static page_entry *lookup_page_table_entry PARAMS ((const void *)); @@ -373,14 +415,60 @@ static void release_pages PARAMS ((void)); static void clear_marks PARAMS ((void)); static void sweep_pages PARAMS ((void)); static void ggc_recalculate_in_use_p PARAMS ((page_entry *)); +static void compute_inverse PARAMS ((unsigned)); +static inline void adjust_depth PARAMS ((void)); -#ifdef GGC_POISON +#ifdef ENABLE_GC_CHECKING static void poison_pages PARAMS ((void)); #endif void debug_print_page_list PARAMS ((int)); +static void push_depth PARAMS ((unsigned int)); +static void push_by_depth PARAMS ((page_entry *, unsigned long *)); -/* Returns non-zero if P was allocated in GC'able memory. */ +/* Push an entry onto G.depth. */ + +inline static void +push_depth (i) + unsigned int i; +{ + if (G.depth_in_use >= G.depth_max) + { + G.depth_max *= 2; + G.depth = (unsigned int *) xrealloc ((char *) G.depth, + G.depth_max * sizeof (unsigned int)); + } + G.depth[G.depth_in_use++] = i; +} + +/* Push an entry onto G.by_depth and G.save_in_use. */ + +inline static void +push_by_depth (p, s) + page_entry *p; + unsigned long *s; +{ + if (G.by_depth_in_use >= G.by_depth_max) + { + G.by_depth_max *= 2; + G.by_depth = (page_entry **) xrealloc ((char *) G.by_depth, + G.by_depth_max * sizeof (page_entry *)); + G.save_in_use = (unsigned long **) xrealloc ((char *) G.save_in_use, + G.by_depth_max * sizeof (unsigned long *)); + } + G.by_depth[G.by_depth_in_use] = p; + G.save_in_use[G.by_depth_in_use++] = s; +} + +/* For the 3.3 release, we will avoid prefetch, as it isn't tested widely. */ +#define prefetch(X) ((void) X) + +#define save_in_use_p_i(__i) \ + (G.save_in_use[__i]) +#define save_in_use_p(__p) \ + (save_in_use_p_i (__p->index_by_depth)) + +/* Returns nonzero if P was allocated in GC'able memory. */ static inline int ggc_allocated_p (p) @@ -412,7 +500,7 @@ ggc_allocated_p (p) return base[L1] && base[L1][L2]; } -/* Traverse the page table and find the entry for a page. +/* Traverse the page table and find the entry for a page. Die (probably) if the object wasn't allocated via GC. */ static inline page_entry * @@ -525,6 +613,11 @@ alloc_anon (pref, size) /* Remember that we allocated this memory. */ G.bytes_mapped += size; + /* Pretend we don't have access to the allocated pages. We'll enable + access to smaller pieces of the area in ggc_alloc. Discard the + handle to avoid handle leak. */ + VALGRIND_DISCARD (VALGRIND_MAKE_NOACCESS (page, size)); + return page; } #endif @@ -719,6 +812,8 @@ alloc_page (order) entry->num_free_objects = num_objects; entry->next_bit_hint = 1; + G.context_depth_allocations |= (unsigned long)1 << G.context_depth; + #ifdef USING_MALLOC_PAGE_GROUPS entry->group = group; set_page_group_in_use (group, page); @@ -732,14 +827,34 @@ alloc_page (order) set_page_table_entry (page, entry); if (GGC_DEBUG_LEVEL >= 2) - fprintf (G.debug_file, - "Allocating page at %p, object size=%ld, data %p-%p\n", - (PTR) entry, (long) OBJECT_SIZE (order), page, + fprintf (G.debug_file, + "Allocating page at %p, object size=%lu, data %p-%p\n", + (PTR) entry, (unsigned long) OBJECT_SIZE (order), page, page + entry_size - 1); return entry; } +/* Adjust the size of G.depth so that no index greater than the one + used by the top of the G.by_depth is used. */ + +static inline void +adjust_depth () +{ + page_entry *top; + + if (G.by_depth_in_use) + { + top = G.by_depth[G.by_depth_in_use-1]; + + /* Peel back indicies in depth that index into by_depth, so that + as new elements are added to by_depth, we note the indicies + of those elements, if they are for new context depths. */ + while (G.depth_in_use > (size_t)top->context_depth+1) + --G.depth_in_use; + } +} + /* For a page that is no longer needed, put it on the free page list. */ static inline void @@ -747,16 +862,44 @@ free_page (entry) page_entry *entry; { if (GGC_DEBUG_LEVEL >= 2) - fprintf (G.debug_file, + fprintf (G.debug_file, "Deallocating page at %p, data %p-%p\n", (PTR) entry, entry->page, entry->page + entry->bytes - 1); + /* Mark the page as inaccessible. Discard the handle to avoid handle + leak. */ + VALGRIND_DISCARD (VALGRIND_MAKE_NOACCESS (entry->page, entry->bytes)); + set_page_table_entry (entry->page, NULL); #ifdef USING_MALLOC_PAGE_GROUPS clear_page_group_in_use (entry->group, entry->page); #endif + if (G.by_depth_in_use > 1) + { + page_entry *top = G.by_depth[G.by_depth_in_use-1]; + + /* If they are at the same depth, put top element into freed + slot. */ + if (entry->context_depth == top->context_depth) + { + int i = entry->index_by_depth; + G.by_depth[i] = top; + G.save_in_use[i] = G.save_in_use[G.by_depth_in_use-1]; + top->index_by_depth = i; + } + else + { + /* We cannot free a page from a context deeper than the + current one. */ + abort (); + } + } + --G.by_depth_in_use; + + adjust_depth (); + entry->next = G.free_pages; G.free_pages = entry; } @@ -817,7 +960,7 @@ release_pages () if (g->in_use == 0) { *gp = g->next; - G.bytes_mapped -= g->alloc_size; + G.bytes_mapped -= g->alloc_size; free (g->allocation); } else @@ -828,16 +971,16 @@ release_pages () /* This table provides a fast way to determine ceil(log_2(size)) for allocation requests. The minimum allocation size is eight bytes. */ -static unsigned char size_lookup[257] = +static unsigned char size_lookup[257] = { - 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, - 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, - 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, - 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, - 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, - 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, + 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, + 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, + 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, + 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, - 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, @@ -849,7 +992,7 @@ static unsigned char size_lookup[257] = 8 }; -/* Allocate a chunk of memory of SIZE bytes. If ZERO is non-zero, the +/* Allocate a chunk of memory of SIZE bytes. If ZERO is nonzero, the memory is zeroed; otherwise, its contents are undefined. */ void * @@ -879,11 +1022,19 @@ ggc_alloc (size) { struct page_entry *new_entry; new_entry = alloc_page (order); - + + new_entry->index_by_depth = G.by_depth_in_use; + push_by_depth (new_entry, 0); + + /* We can skip context depths, if we do, make sure we go all the + way to the new depth. */ + while (new_entry->context_depth >= G.depth_in_use) + push_depth (G.by_depth_in_use-1); + /* If this is the only entry, it's also the tail. */ if (entry == NULL) G.page_tails[order] = new_entry; - + /* Put new pages at the head of the page list. */ new_entry->next = entry; entry = new_entry; @@ -905,7 +1056,7 @@ ggc_alloc (size) unsigned hint = entry->next_bit_hint; word = hint / HOST_BITS_PER_LONG; bit = hint % HOST_BITS_PER_LONG; - + /* If the hint didn't work, scan the bitmap from the beginning. */ if ((entry->in_use_p[word] >> bit) & 1) { @@ -943,20 +1094,37 @@ ggc_alloc (size) /* Calculate the object's address. */ result = entry->page + object_offset; -#ifdef GGC_POISON +#ifdef ENABLE_GC_CHECKING + /* Keep poisoning-by-writing-0xaf the object, in an attempt to keep the + exact same semantics in presence of memory bugs, regardless of + ENABLE_VALGRIND_CHECKING. We override this request below. Drop the + handle to avoid handle leak. */ + VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (result, OBJECT_SIZE (order))); + /* `Poison' the entire allocated object, including any padding at the end. */ memset (result, 0xaf, OBJECT_SIZE (order)); + + /* Make the bytes after the end of the object unaccessible. Discard the + handle to avoid handle leak. */ + VALGRIND_DISCARD (VALGRIND_MAKE_NOACCESS ((char *) result + size, + OBJECT_SIZE (order) - size)); #endif + /* Tell Valgrind that the memory is there, but its content isn't + defined. The bytes at the end of the object are still marked + unaccessible. */ + VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (result, size)); + /* Keep track of how many bytes are being allocated. This information is used in deciding when to collect. */ G.allocated += OBJECT_SIZE (order); if (GGC_DEBUG_LEVEL >= 3) - fprintf (G.debug_file, - "Allocating object, requested size=%ld, actual=%ld at %p on %p\n", - (long) size, (long) OBJECT_SIZE (order), result, (PTR) entry); + fprintf (G.debug_file, + "Allocating object, requested size=%lu, actual=%lu at %p on %p\n", + (unsigned long) size, (unsigned long) OBJECT_SIZE (order), result, + (PTR) entry); return result; } @@ -983,10 +1151,10 @@ ggc_set_mark (p) /* Calculate the index of the object on the page; this is its bit position in the in_use_p bitmap. */ - bit = (((const char *) p) - entry->page) / OBJECT_SIZE (entry->order); + bit = OFFSET_TO_BIT (((const char *) p) - entry->page, entry->order); word = bit / HOST_BITS_PER_LONG; mask = (unsigned long) 1 << (bit % HOST_BITS_PER_LONG); - + /* If the bit was previously set, skip it. */ if (entry->in_use_p[word] & mask) return 1; @@ -1001,7 +1169,7 @@ ggc_set_mark (p) return 0; } -/* Return 1 if P has been marked, zero otherwise. +/* Return 1 if P has been marked, zero otherwise. P must have been allocated by the GC allocator; it mustn't point to static objects, stack variables, or memory allocated with malloc. */ @@ -1023,10 +1191,10 @@ ggc_marked_p (p) /* Calculate the index of the object on the page; this is its bit position in the in_use_p bitmap. */ - bit = (((const char *) p) - entry->page) / OBJECT_SIZE (entry->order); + bit = OFFSET_TO_BIT (((const char *) p) - entry->page, entry->order); word = bit / HOST_BITS_PER_LONG; mask = (unsigned long) 1 << (bit % HOST_BITS_PER_LONG); - + return (entry->in_use_p[word] & mask) != 0; } @@ -1040,8 +1208,49 @@ ggc_get_size (p) return OBJECT_SIZE (pe->order); } -/* Initialize the ggc-mmap allocator. */ +/* Subroutine of init_ggc which computes the pair of numbers used to + perform division by OBJECT_SIZE (order) and fills in inverse_table[]. + + This algorithm is taken from Granlund and Montgomery's paper + "Division by Invariant Integers using Multiplication" + (Proc. SIGPLAN PLDI, 1994), section 9 (Exact division by + constants). */ + +static void +compute_inverse (order) + unsigned order; +{ + unsigned size, inv, e; + + /* There can be only one object per "page" in a bucket for sizes + larger than half a machine page; it will always have offset zero. */ + if (OBJECT_SIZE (order) > G.pagesize/2) + { + if (OBJECTS_PER_PAGE (order) != 1) + abort (); + + DIV_MULT (order) = 1; + DIV_SHIFT (order) = 0; + return; + } + + size = OBJECT_SIZE (order); + e = 0; + while (size % 2 == 0) + { + e++; + size >>= 1; + } + + inv = size; + while (inv * size != 1) + inv = inv * (2 - inv*size); + + DIV_MULT (order) = inv; + DIV_SHIFT (order) = e; +} +/* Initialize the ggc-mmap allocator. */ void init_ggc () { @@ -1053,7 +1262,7 @@ init_ggc () #ifdef HAVE_MMAP_DEV_ZERO G.dev_zero_fd = open ("/dev/zero", O_RDONLY); if (G.dev_zero_fd == -1) - abort (); + fatal_io_error ("open /dev/zero"); #endif #if 0 @@ -1062,8 +1271,6 @@ init_ggc () G.debug_file = stdout; #endif - G.allocated_last_gc = GGC_MIN_LAST_ALLOCATED; - #ifdef USING_MMAP /* StunOS has an amazing off-by-one error for the first mmap allocation after fiddling with RLIMIT_STACK. The result, as hard as it is to @@ -1104,12 +1311,13 @@ init_ggc () object_size_table[order] = s; } - /* Initialize the objects-per-page table. */ + /* Initialize the objects-per-page and inverse tables. */ for (order = 0; order < NUM_ORDERS; ++order) { objects_per_page_table[order] = G.pagesize / OBJECT_SIZE (order); if (objects_per_page_table[order] == 0) objects_per_page_table[order] = 1; + compute_inverse (order); } /* Reset the size_lookup array to put appropriately sized objects in @@ -1125,6 +1333,15 @@ init_ggc () for (i = OBJECT_SIZE (order); size_lookup [i] == o; --i) size_lookup[i] = order; } + + G.depth_in_use = 0; + G.depth_max = 10; + G.depth = (unsigned int *) xmalloc (G.depth_max * sizeof (unsigned int)); + + G.by_depth_in_use = 0; + G.by_depth_max = INITIAL_PTE_COUNT; + G.by_depth = (page_entry **) xmalloc (G.by_depth_max * sizeof (page_entry *)); + G.save_in_use = (unsigned long **) xmalloc (G.by_depth_max * sizeof (unsigned long *)); } /* Increment the `GC context'. Objects allocated in an outer context @@ -1136,7 +1353,7 @@ ggc_push_context () ++G.context_depth; /* Die on wrap. */ - if (G.context_depth == 0) + if (G.context_depth >= HOST_BITS_PER_LONG) abort (); } @@ -1150,7 +1367,7 @@ ggc_recalculate_in_use_p (p) unsigned int i; size_t num_objects; - /* Because the past-the-end bit in in_use_p is always set, we + /* Because the past-the-end bit in in_use_p is always set, we pretend there is one additional object. */ num_objects = OBJECTS_PER_PAGE (p->order) + 1; @@ -1158,7 +1375,7 @@ ggc_recalculate_in_use_p (p) p->num_free_objects = num_objects; /* Combine the IN_USE_P and SAVE_IN_USE_P arrays. */ - for (i = 0; + for (i = 0; i < CEIL (BITMAP_SIZE (num_objects), sizeof (*p->in_use_p)); ++i) @@ -1167,7 +1384,7 @@ ggc_recalculate_in_use_p (p) /* Something is in use if it is marked, or if it was in use in a context further down the context stack. */ - p->in_use_p[i] |= p->save_in_use_p[i]; + p->in_use_p[i] |= save_in_use_p (p)[i]; /* Decrement the free object count for every object allocated. */ for (j = p->in_use_p[i]; j; j >>= 1) @@ -1178,19 +1395,88 @@ ggc_recalculate_in_use_p (p) abort (); } -/* Decrement the `GC context'. All objects allocated since the +/* Decrement the `GC context'. All objects allocated since the previous ggc_push_context are migrated to the outer context. */ void ggc_pop_context () { - unsigned order, depth; + unsigned long omask; + unsigned int depth, i, e; +#ifdef ENABLE_CHECKING + unsigned int order; +#endif depth = --G.context_depth; + omask = (unsigned long)1 << (depth + 1); + + if (!((G.context_depth_allocations | G.context_depth_collections) & omask)) + return; + + G.context_depth_allocations |= (G.context_depth_allocations & omask) >> 1; + G.context_depth_allocations &= omask - 1; + G.context_depth_collections &= omask - 1; + + /* The G.depth array is shortend so that the last index is the + context_depth of the top element of by_depth. */ + if (depth+1 < G.depth_in_use) + e = G.depth[depth+1]; + else + e = G.by_depth_in_use; + + /* We might not have any PTEs of depth depth. */ + if (depth < G.depth_in_use) + { + + /* First we go through all the pages at depth depth to + recalculate the in use bits. */ + for (i = G.depth[depth]; i < e; ++i) + { + page_entry *p; + +#ifdef ENABLE_CHECKING + p = G.by_depth[i]; + + /* Check that all of the pages really are at the depth that + we expect. */ + if (p->context_depth != depth) + abort (); + if (p->index_by_depth != i) + abort (); +#endif + + prefetch (&save_in_use_p_i (i+8)); + prefetch (&save_in_use_p_i (i+16)); + if (save_in_use_p_i (i)) + { + p = G.by_depth[i]; + ggc_recalculate_in_use_p (p); + free (save_in_use_p_i (i)); + save_in_use_p_i (i) = 0; + } + } + } - /* Any remaining pages in the popped context are lowered to the new - current context; i.e. objects allocated in the popped context and - left over are imported into the previous context. */ + /* Then, we reset all page_entries with a depth greater than depth + to be at depth. */ + for (i = e; i < G.by_depth_in_use; ++i) + { + page_entry *p = G.by_depth[i]; + + /* Check that all of the pages really are at the depth we + expect. */ +#ifdef ENABLE_CHECKING + if (p->context_depth <= depth) + abort (); + if (p->index_by_depth != i) + abort (); +#endif + p->context_depth = depth; + } + + adjust_depth (); + +#ifdef ENABLE_CHECKING for (order = 2; order < NUM_ORDERS; order++) { page_entry *p; @@ -1198,18 +1484,12 @@ ggc_pop_context () for (p = G.pages[order]; p != NULL; p = p->next) { if (p->context_depth > depth) - p->context_depth = depth; - - /* If this page is now in the topmost context, and we'd - saved its allocation state, restore it. */ - else if (p->context_depth == depth && p->save_in_use_p) - { - ggc_recalculate_in_use_p (p); - free (p->save_in_use_p); - p->save_in_use_p = 0; - } + abort (); + else if (p->context_depth == depth && save_in_use_p (p)) + abort (); } } +#endif } /* Unmark all objects. */ @@ -1238,9 +1518,9 @@ clear_marks () marks. So, back them up first. */ if (p->context_depth < G.context_depth) { - if (! p->save_in_use_p) - p->save_in_use_p = xmalloc (bitmap_size); - memcpy (p->save_in_use_p, p->in_use_p, bitmap_size); + if (! save_in_use_p (p)) + save_in_use_p (p) = xmalloc (bitmap_size); + memcpy (save_in_use_p (p), p->in_use_p, bitmap_size); } /* Reset reset the number of free objects and clear the @@ -1249,7 +1529,7 @@ clear_marks () memset (p->in_use_p, 0, bitmap_size); /* Make sure the one-past-the-end bit is always set. */ - p->in_use_p[num_objects / HOST_BITS_PER_LONG] + p->in_use_p[num_objects / HOST_BITS_PER_LONG] = ((unsigned long) 1 << (num_objects % HOST_BITS_PER_LONG)); } } @@ -1273,7 +1553,7 @@ sweep_pages () size_t live_objects; page_entry *p, *previous; int done; - + p = G.pages[order]; if (p == NULL) continue; @@ -1351,7 +1631,7 @@ sweep_pages () previous = p; p = next; - } + } while (! done); /* Now, restore the in_use_p vectors for any pages from contexts @@ -1362,7 +1642,7 @@ sweep_pages () } } -#ifdef GGC_POISON +#ifdef ENABLE_GC_CHECKING /* Clobber all free objects. */ static inline void @@ -1393,7 +1673,19 @@ poison_pages () word = i / HOST_BITS_PER_LONG; bit = i % HOST_BITS_PER_LONG; if (((p->in_use_p[word] >> bit) & 1) == 0) - memset (p->page + i * size, 0xa5, size); + { + char *object = p->page + i * size; + + /* Keep poison-by-write when we expect to use Valgrind, + so the exact same memory semantics is kept, in case + there are memory errors. We override this request + below. */ + VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (object, size)); + memset (object, 0xa5, size); + + /* Drop the handle to avoid handle leak. */ + VALGRIND_DISCARD (VALGRIND_MAKE_NOACCESS (object, size)); + } } } } @@ -1408,10 +1700,13 @@ ggc_collect () /* Avoid frequent unnecessary work by skipping collection if the total allocations haven't expanded much since the last collection. */ -#ifndef GGC_ALWAYS_COLLECT - if (G.allocated < GGC_MIN_EXPAND_FOR_GC * G.allocated_last_gc) + float allocated_last_gc = + MAX (G.allocated_last_gc, (size_t)PARAM_VALUE (GGC_MIN_HEAPSIZE) * 1024); + + float min_expand = allocated_last_gc * PARAM_VALUE (GGC_MIN_EXPAND) / 100; + + if (G.allocated < allocated_last_gc + min_expand) return; -#endif timevar_push (TV_GC); if (!quiet_flag) @@ -1421,22 +1716,23 @@ ggc_collect () sweep phase. */ G.allocated = 0; - /* Release the pages we freed the last time we collected, but didn't + /* Release the pages we freed the last time we collected, but didn't reuse in the interim. */ release_pages (); + /* Indicate that we've seen collections at this context depth. */ + G.context_depth_collections = ((unsigned long)1 << (G.context_depth + 1)) - 1; + clear_marks (); ggc_mark_roots (); - -#ifdef GGC_POISON + +#ifdef ENABLE_GC_CHECKING poison_pages (); #endif sweep_pages (); G.allocated_last_gc = G.allocated; - if (G.allocated_last_gc < GGC_MIN_LAST_ALLOCATED) - G.allocated_last_gc = GGC_MIN_LAST_ALLOCATED; timevar_pop (TV_GC); @@ -1461,7 +1757,7 @@ ggc_print_statistics () /* Clear the statistics. */ memset (&stats, 0, sizeof (stats)); - + /* Make sure collection will really occur. */ G.allocated_last_gc = 0; @@ -1472,7 +1768,7 @@ ggc_print_statistics () there as part of the total allocated memory. */ release_pages (); - /* Collect some information about the various sizes of + /* Collect some information about the various sizes of allocation. */ fprintf (stderr, "\n%-5s %10s %10s %10s\n", "Size", "Allocated", "Used", "Overhead"); @@ -1495,19 +1791,20 @@ ggc_print_statistics () for (p = G.pages[i]; p; p = p->next) { allocated += p->bytes; - in_use += + in_use += (OBJECTS_PER_PAGE (i) - p->num_free_objects) * OBJECT_SIZE (i); overhead += (sizeof (page_entry) - sizeof (long) + BITMAP_SIZE (OBJECTS_PER_PAGE (i) + 1)); } - fprintf (stderr, "%-5d %10ld%c %10ld%c %10ld%c\n", OBJECT_SIZE (i), + fprintf (stderr, "%-5lu %10lu%c %10lu%c %10lu%c\n", + (unsigned long) OBJECT_SIZE (i), SCALE (allocated), LABEL (allocated), SCALE (in_use), LABEL (in_use), SCALE (overhead), LABEL (overhead)); total_overhead += overhead; } - fprintf (stderr, "%-5s %10ld%c %10ld%c %10ld%c\n", "Total", + fprintf (stderr, "%-5s %10lu%c %10lu%c %10lu%c\n", "Total", SCALE (G.bytes_mapped), LABEL (G.bytes_mapped), SCALE (G.allocated), LABEL(G.allocated), SCALE (total_overhead), LABEL (total_overhead)); |
