1 /* "Bag-of-pages" garbage collector for the GNU compiler.
2 Copyright (C) 1999-2015 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
33 #include "diagnostic-core.h"
36 #include "ggc-internal.h"
41 #include "plugin-api.h"
45 #include "hard-reg-set.h"
52 #include "basic-block.h"
54 /* Prefer MAP_ANON(YMOUS) to /dev/zero, since we don't need to keep a
55 file open. Prefer either to valloc. */
57 # undef HAVE_MMAP_DEV_ZERO
61 #ifdef HAVE_MMAP_DEV_ZERO
66 #define USING_MALLOC_PAGE_GROUPS
69 #if defined(HAVE_MADVISE) && HAVE_DECL_MADVISE && defined(MADV_DONTNEED) \
70 && defined(USING_MMAP)
71 # define USING_MADVISE
76 This garbage-collecting allocator allocates objects on one of a set
77 of pages. Each page can allocate objects of a single size only;
78 available sizes are powers of two starting at four bytes. The size
79 of an allocation request is rounded up to the next power of two
80 (`order'), and satisfied from the appropriate page.
82 Each page is recorded in a page-entry, which also maintains an
83 in-use bitmap of object positions on the page. This allows the
84 allocation state of a particular object to be flipped without
85 touching the page itself.
87 Each page-entry also has a context depth, which is used to track
88 pushing and popping of allocation contexts. Only objects allocated
89 in the current (highest-numbered) context may be collected.
91 Page entries are arranged in an array of singly-linked lists. The
92 array is indexed by the allocation size, in bits, of the pages on
93 it; i.e. all pages on a list allocate objects of the same size.
94 Pages are ordered on the list such that all non-full pages precede
95 all full pages, with non-full pages arranged in order of decreasing
98 Empty pages (of all orders) are kept on a single page cache list,
99 and are considered first when new pages are required; they are
100 deallocated at the start of the next collection if they haven't
101 been recycled by then. */
103 /* Define GGC_DEBUG_LEVEL to print debugging information.
104 0: No debugging output.
105 1: GC statistics only.
106 2: Page-entry allocations/deallocations as well.
107 3: Object allocations as well.
108 4: Object marks as well. */
109 #define GGC_DEBUG_LEVEL (0)
111 #ifndef HOST_BITS_PER_PTR
112 #define HOST_BITS_PER_PTR HOST_BITS_PER_LONG
116 /* A two-level tree is used to look up the page-entry for a given
117 pointer. Two chunks of the pointer's bits are extracted to index
118 the first and second levels of the tree, as follows:
122 msb +----------------+----+------+------+ lsb
128 The bottommost HOST_PAGE_SIZE_BITS are ignored, since page-entry
129 pages are aligned on system page boundaries. The next most
130 significant PAGE_L2_BITS and PAGE_L1_BITS are the second and first
131 index values in the lookup table, respectively.
133 For 32-bit architectures and the settings below, there are no
134 leftover bits. For architectures with wider pointers, the lookup
135 tree points to a list of pages, which must be scanned to find the
138 #define PAGE_L1_BITS (8)
139 #define PAGE_L2_BITS (32 - PAGE_L1_BITS - G.lg_pagesize)
140 #define PAGE_L1_SIZE ((uintptr_t) 1 << PAGE_L1_BITS)
141 #define PAGE_L2_SIZE ((uintptr_t) 1 << PAGE_L2_BITS)
143 #define LOOKUP_L1(p) \
144 (((uintptr_t) (p) >> (32 - PAGE_L1_BITS)) & ((1 << PAGE_L1_BITS) - 1))
146 #define LOOKUP_L2(p) \
147 (((uintptr_t) (p) >> G.lg_pagesize) & ((1 << PAGE_L2_BITS) - 1))
149 /* The number of objects per allocation page, for objects on a page of
150 the indicated ORDER. */
151 #define OBJECTS_PER_PAGE(ORDER) objects_per_page_table[ORDER]
153 /* The number of objects in P. */
154 #define OBJECTS_IN_PAGE(P) ((P)->bytes / OBJECT_SIZE ((P)->order))
156 /* The size of an object on a page of the indicated ORDER. */
157 #define OBJECT_SIZE(ORDER) object_size_table[ORDER]
159 /* For speed, we avoid doing a general integer divide to locate the
160 offset in the allocation bitmap, by precalculating numbers M, S
161 such that (O * M) >> S == O / Z (modulo 2^32), for any offset O
162 within the page which is evenly divisible by the object size Z. */
163 #define DIV_MULT(ORDER) inverse_table[ORDER].mult
164 #define DIV_SHIFT(ORDER) inverse_table[ORDER].shift
165 #define OFFSET_TO_BIT(OFFSET, ORDER) \
166 (((OFFSET) * DIV_MULT (ORDER)) >> DIV_SHIFT (ORDER))
168 /* We use this structure to determine the alignment required for
169 allocations. For power-of-two sized allocations, that's not a
170 problem, but it does matter for odd-sized allocations.
171 We do not care about alignment for floating-point types. */
173 struct max_alignment
{
181 /* The biggest alignment required. */
183 #define MAX_ALIGNMENT (offsetof (struct max_alignment, u))
186 /* The number of extra orders, not corresponding to power-of-two sized
189 #define NUM_EXTRA_ORDERS ARRAY_SIZE (extra_order_size_table)
191 #define RTL_SIZE(NSLOTS) \
192 (RTX_HDR_SIZE + (NSLOTS) * sizeof (rtunion))
194 #define TREE_EXP_SIZE(OPS) \
195 (sizeof (struct tree_exp) + ((OPS) - 1) * sizeof (tree))
197 /* The Ith entry is the maximum size of an object to be stored in the
198 Ith extra order. Adding a new entry to this array is the *only*
199 thing you need to do to add a new special allocation size. */
201 static const size_t extra_order_size_table
[] = {
202 /* Extra orders for small non-power-of-two multiples of MAX_ALIGNMENT.
203 There are a lot of structures with these sizes and explicitly
204 listing them risks orders being dropped because they changed size. */
216 sizeof (struct tree_decl_non_common
),
217 sizeof (struct tree_field_decl
),
218 sizeof (struct tree_parm_decl
),
219 sizeof (struct tree_var_decl
),
220 sizeof (struct tree_type_non_common
),
221 sizeof (struct function
),
222 sizeof (struct basic_block_def
),
223 sizeof (struct cgraph_node
),
224 sizeof (struct loop
),
227 /* The total number of orders. */
229 #define NUM_ORDERS (HOST_BITS_PER_PTR + NUM_EXTRA_ORDERS)
231 /* Compute the smallest nonnegative number which when added to X gives
234 #define ROUND_UP_VALUE(x, f) ((f) - 1 - ((f) - 1 + (x)) % (f))
236 /* Compute the smallest multiple of F that is >= X. */
238 #define ROUND_UP(x, f) (CEIL (x, f) * (f))
240 /* Round X to next multiple of the page size */
242 #define PAGE_ALIGN(x) (((x) + G.pagesize - 1) & ~(G.pagesize - 1))
244 /* The Ith entry is the number of objects on a page or order I. */
246 static unsigned objects_per_page_table
[NUM_ORDERS
];
248 /* The Ith entry is the size of an object on a page of order I. */
250 static size_t object_size_table
[NUM_ORDERS
];
252 /* The Ith entry is a pair of numbers (mult, shift) such that
253 ((k * mult) >> shift) mod 2^32 == (k / OBJECT_SIZE(I)) mod 2^32,
254 for all k evenly divisible by OBJECT_SIZE(I). */
261 inverse_table
[NUM_ORDERS
];
263 /* A page_entry records the status of an allocation page. This
264 structure is dynamically sized to fit the bitmap in_use_p. */
265 typedef struct page_entry
267 /* The next page-entry with objects of the same size, or NULL if
268 this is the last page-entry. */
269 struct page_entry
*next
;
271 /* The previous page-entry with objects of the same size, or NULL if
272 this is the first page-entry. The PREV pointer exists solely to
273 keep the cost of ggc_free manageable. */
274 struct page_entry
*prev
;
276 /* The number of bytes allocated. (This will always be a multiple
277 of the host system page size.) */
280 /* The address at which the memory is allocated. */
283 #ifdef USING_MALLOC_PAGE_GROUPS
284 /* Back pointer to the page group this page came from. */
285 struct page_group
*group
;
288 /* This is the index in the by_depth varray where this page table
290 unsigned long index_by_depth
;
292 /* Context depth of this page. */
293 unsigned short context_depth
;
295 /* The number of free objects remaining on this page. */
296 unsigned short num_free_objects
;
298 /* A likely candidate for the bit position of a free object for the
299 next allocation from this page. */
300 unsigned short next_bit_hint
;
302 /* The lg of size of objects allocated from this page. */
305 /* Discarded page? */
308 /* A bit vector indicating whether or not objects are in use. The
309 Nth bit is one if the Nth object on this page is allocated. This
310 array is dynamically sized. */
311 unsigned long in_use_p
[1];
314 #ifdef USING_MALLOC_PAGE_GROUPS
315 /* A page_group describes a large allocation from malloc, from which
316 we parcel out aligned pages. */
317 typedef struct page_group
319 /* A linked list of all extant page groups. */
320 struct page_group
*next
;
322 /* The address we received from malloc. */
325 /* The size of the block. */
328 /* A bitmask of pages in use. */
333 #if HOST_BITS_PER_PTR <= 32
335 /* On 32-bit hosts, we use a two level page table, as pictured above. */
336 typedef page_entry
**page_table
[PAGE_L1_SIZE
];
340 /* On 64-bit hosts, we use the same two level page tables plus a linked
341 list that disambiguates the top 32-bits. There will almost always be
342 exactly one entry in the list. */
343 typedef struct page_table_chain
345 struct page_table_chain
*next
;
347 page_entry
**table
[PAGE_L1_SIZE
];
355 finalizer (void *addr
, void (*f
)(void *)) : m_addr (addr
), m_function (f
) {}
357 void *addr () const { return m_addr
; }
359 void call () const { m_function (m_addr
); }
363 void (*m_function
)(void *);
369 vec_finalizer (uintptr_t addr
, void (*f
)(void *), size_t s
, size_t n
) :
370 m_addr (addr
), m_function (f
), m_object_size (s
), m_n_objects (n
) {}
374 for (size_t i
= 0; i
< m_n_objects
; i
++)
375 m_function (reinterpret_cast<void *> (m_addr
+ (i
* m_object_size
)));
378 void *addr () const { return reinterpret_cast<void *> (m_addr
); }
382 void (*m_function
)(void *);
383 size_t m_object_size
;
387 #ifdef ENABLE_GC_ALWAYS_COLLECT
388 /* List of free objects to be verified as actually free on the
393 struct free_object
*next
;
397 /* The rest of the global variables. */
398 static struct ggc_globals
400 /* The Nth element in this array is a page with objects of size 2^N.
401 If there are any pages with free objects, they will be at the
402 head of the list. NULL if there are no page-entries for this
404 page_entry
*pages
[NUM_ORDERS
];
406 /* The Nth element in this array is the last page with objects of
407 size 2^N. NULL if there are no page-entries for this object
409 page_entry
*page_tails
[NUM_ORDERS
];
411 /* Lookup table for associating allocation pages with object addresses. */
414 /* The system's page size. */
418 /* Bytes currently allocated. */
421 /* Bytes currently allocated at the end of the last collection. */
422 size_t allocated_last_gc
;
424 /* Total amount of memory mapped. */
427 /* Bit N set if any allocations have been done at context depth N. */
428 unsigned long context_depth_allocations
;
430 /* Bit N set if any collections have been done at context depth N. */
431 unsigned long context_depth_collections
;
433 /* The current depth in the context stack. */
434 unsigned short context_depth
;
436 /* A file descriptor open to /dev/zero for reading. */
437 #if defined (HAVE_MMAP_DEV_ZERO)
441 /* A cache of free system pages. */
442 page_entry
*free_pages
;
444 #ifdef USING_MALLOC_PAGE_GROUPS
445 page_group
*page_groups
;
448 /* The file descriptor for debugging output. */
451 /* Current number of elements in use in depth below. */
452 unsigned int depth_in_use
;
454 /* Maximum number of elements that can be used before resizing. */
455 unsigned int depth_max
;
457 /* Each element of this array is an index in by_depth where the given
458 depth starts. This structure is indexed by that given depth we
459 are interested in. */
462 /* Current number of elements in use in by_depth below. */
463 unsigned int by_depth_in_use
;
465 /* Maximum number of elements that can be used before resizing. */
466 unsigned int by_depth_max
;
468 /* Each element of this array is a pointer to a page_entry, all
469 page_entries can be found in here by increasing depth.
470 index_by_depth in the page_entry is the index into this data
471 structure where that page_entry can be found. This is used to
472 speed up finding all page_entries at a particular depth. */
473 page_entry
**by_depth
;
475 /* Each element is a pointer to the saved in_use_p bits, if any,
476 zero otherwise. We allocate them all together, to enable a
477 better runtime data access pattern. */
478 unsigned long **save_in_use
;
480 /* Finalizers for single objects. */
481 vec
<finalizer
> finalizers
;
483 /* Finalizers for vectors of objects. */
484 vec
<vec_finalizer
> vec_finalizers
;
486 #ifdef ENABLE_GC_ALWAYS_COLLECT
487 /* List of free objects to be verified as actually free on the
489 struct free_object
*free_object_list
;
494 /* Total GC-allocated memory. */
495 unsigned long long total_allocated
;
496 /* Total overhead for GC-allocated memory. */
497 unsigned long long total_overhead
;
499 /* Total allocations and overhead for sizes less than 32, 64 and 128.
500 These sizes are interesting because they are typical cache line
503 unsigned long long total_allocated_under32
;
504 unsigned long long total_overhead_under32
;
506 unsigned long long total_allocated_under64
;
507 unsigned long long total_overhead_under64
;
509 unsigned long long total_allocated_under128
;
510 unsigned long long total_overhead_under128
;
512 /* The allocations for each of the allocation orders. */
513 unsigned long long total_allocated_per_order
[NUM_ORDERS
];
515 /* The overhead for each of the allocation orders. */
516 unsigned long long total_overhead_per_order
[NUM_ORDERS
];
520 /* True if a gc is currently taking place. */
522 static bool in_gc
= false;
524 /* The size in bytes required to maintain a bitmap for the objects
526 #define BITMAP_SIZE(Num_objects) \
527 (CEIL ((Num_objects), HOST_BITS_PER_LONG) * sizeof (long))
529 /* Allocate pages in chunks of this size, to throttle calls to memory
530 allocation routines. The first page is used, the rest go onto the
531 free list. This cannot be larger than HOST_BITS_PER_INT for the
532 in_use bitmask for page_group. Hosts that need a different value
533 can override this by defining GGC_QUIRE_SIZE explicitly. */
534 #ifndef GGC_QUIRE_SIZE
536 # define GGC_QUIRE_SIZE 512 /* 2MB for 4K pages */
538 # define GGC_QUIRE_SIZE 16
542 /* Initial guess as to how many page table entries we might need. */
543 #define INITIAL_PTE_COUNT 128
545 static int ggc_allocated_p (const void *);
546 static page_entry
*lookup_page_table_entry (const void *);
547 static void set_page_table_entry (void *, page_entry
*);
549 static char *alloc_anon (char *, size_t, bool check
);
551 #ifdef USING_MALLOC_PAGE_GROUPS
552 static size_t page_group_index (char *, char *);
553 static void set_page_group_in_use (page_group
*, char *);
554 static void clear_page_group_in_use (page_group
*, char *);
556 static struct page_entry
* alloc_page (unsigned);
557 static void free_page (struct page_entry
*);
558 static void release_pages (void);
559 static void clear_marks (void);
560 static void sweep_pages (void);
561 static void ggc_recalculate_in_use_p (page_entry
*);
562 static void compute_inverse (unsigned);
563 static inline void adjust_depth (void);
564 static void move_ptes_to_front (int, int);
566 void debug_print_page_list (int);
567 static void push_depth (unsigned int);
568 static void push_by_depth (page_entry
*, unsigned long *);
570 /* Push an entry onto G.depth. */
573 push_depth (unsigned int i
)
575 if (G
.depth_in_use
>= G
.depth_max
)
578 G
.depth
= XRESIZEVEC (unsigned int, G
.depth
, G
.depth_max
);
580 G
.depth
[G
.depth_in_use
++] = i
;
583 /* Push an entry onto G.by_depth and G.save_in_use. */
586 push_by_depth (page_entry
*p
, unsigned long *s
)
588 if (G
.by_depth_in_use
>= G
.by_depth_max
)
591 G
.by_depth
= XRESIZEVEC (page_entry
*, G
.by_depth
, G
.by_depth_max
);
592 G
.save_in_use
= XRESIZEVEC (unsigned long *, G
.save_in_use
,
595 G
.by_depth
[G
.by_depth_in_use
] = p
;
596 G
.save_in_use
[G
.by_depth_in_use
++] = s
;
599 #if (GCC_VERSION < 3001)
600 #define prefetch(X) ((void) X)
602 #define prefetch(X) __builtin_prefetch (X)
605 #define save_in_use_p_i(__i) \
607 #define save_in_use_p(__p) \
608 (save_in_use_p_i (__p->index_by_depth))
610 /* Returns nonzero if P was allocated in GC'able memory. */
613 ggc_allocated_p (const void *p
)
618 #if HOST_BITS_PER_PTR <= 32
621 page_table table
= G
.lookup
;
622 uintptr_t high_bits
= (uintptr_t) p
& ~ (uintptr_t) 0xffffffff;
627 if (table
->high_bits
== high_bits
)
631 base
= &table
->table
[0];
634 /* Extract the level 1 and 2 indices. */
638 return base
[L1
] && base
[L1
][L2
];
641 /* Traverse the page table and find the entry for a page.
642 Die (probably) if the object wasn't allocated via GC. */
644 static inline page_entry
*
645 lookup_page_table_entry (const void *p
)
650 #if HOST_BITS_PER_PTR <= 32
653 page_table table
= G
.lookup
;
654 uintptr_t high_bits
= (uintptr_t) p
& ~ (uintptr_t) 0xffffffff;
655 while (table
->high_bits
!= high_bits
)
657 base
= &table
->table
[0];
660 /* Extract the level 1 and 2 indices. */
667 /* Set the page table entry for a page. */
670 set_page_table_entry (void *p
, page_entry
*entry
)
675 #if HOST_BITS_PER_PTR <= 32
679 uintptr_t high_bits
= (uintptr_t) p
& ~ (uintptr_t) 0xffffffff;
680 for (table
= G
.lookup
; table
; table
= table
->next
)
681 if (table
->high_bits
== high_bits
)
684 /* Not found -- allocate a new table. */
685 table
= XCNEW (struct page_table_chain
);
686 table
->next
= G
.lookup
;
687 table
->high_bits
= high_bits
;
690 base
= &table
->table
[0];
693 /* Extract the level 1 and 2 indices. */
697 if (base
[L1
] == NULL
)
698 base
[L1
] = XCNEWVEC (page_entry
*, PAGE_L2_SIZE
);
700 base
[L1
][L2
] = entry
;
703 /* Prints the page-entry for object size ORDER, for debugging. */
706 debug_print_page_list (int order
)
709 printf ("Head=%p, Tail=%p:\n", (void *) G
.pages
[order
],
710 (void *) G
.page_tails
[order
]);
714 printf ("%p(%1d|%3d) -> ", (void *) p
, p
->context_depth
,
715 p
->num_free_objects
);
723 /* Allocate SIZE bytes of anonymous memory, preferably near PREF,
724 (if non-null). The ifdef structure here is intended to cause a
725 compile error unless exactly one of the HAVE_* is defined. */
728 alloc_anon (char *pref ATTRIBUTE_UNUSED
, size_t size
, bool check
)
730 #ifdef HAVE_MMAP_ANON
731 char *page
= (char *) mmap (pref
, size
, PROT_READ
| PROT_WRITE
,
732 MAP_PRIVATE
| MAP_ANONYMOUS
, -1, 0);
734 #ifdef HAVE_MMAP_DEV_ZERO
735 char *page
= (char *) mmap (pref
, size
, PROT_READ
| PROT_WRITE
,
736 MAP_PRIVATE
, G
.dev_zero_fd
, 0);
739 if (page
== (char *) MAP_FAILED
)
743 perror ("virtual memory exhausted");
744 exit (FATAL_EXIT_CODE
);
747 /* Remember that we allocated this memory. */
748 G
.bytes_mapped
+= size
;
750 /* Pretend we don't have access to the allocated pages. We'll enable
751 access to smaller pieces of the area in ggc_internal_alloc. Discard the
752 handle to avoid handle leak. */
753 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (page
, size
));
758 #ifdef USING_MALLOC_PAGE_GROUPS
759 /* Compute the index for this page into the page group. */
762 page_group_index (char *allocation
, char *page
)
764 return (size_t) (page
- allocation
) >> G
.lg_pagesize
;
767 /* Set and clear the in_use bit for this page in the page group. */
770 set_page_group_in_use (page_group
*group
, char *page
)
772 group
->in_use
|= 1 << page_group_index (group
->allocation
, page
);
776 clear_page_group_in_use (page_group
*group
, char *page
)
778 group
->in_use
&= ~(1 << page_group_index (group
->allocation
, page
));
782 /* Allocate a new page for allocating objects of size 2^ORDER,
783 and return an entry for it. The entry is not added to the
784 appropriate page_table list. */
786 static inline struct page_entry
*
787 alloc_page (unsigned order
)
789 struct page_entry
*entry
, *p
, **pp
;
793 size_t page_entry_size
;
795 #ifdef USING_MALLOC_PAGE_GROUPS
799 num_objects
= OBJECTS_PER_PAGE (order
);
800 bitmap_size
= BITMAP_SIZE (num_objects
+ 1);
801 page_entry_size
= sizeof (page_entry
) - sizeof (long) + bitmap_size
;
802 entry_size
= num_objects
* OBJECT_SIZE (order
);
803 if (entry_size
< G
.pagesize
)
804 entry_size
= G
.pagesize
;
805 entry_size
= PAGE_ALIGN (entry_size
);
810 /* Check the list of free pages for one we can use. */
811 for (pp
= &G
.free_pages
, p
= *pp
; p
; pp
= &p
->next
, p
= *pp
)
812 if (p
->bytes
== entry_size
)
818 G
.bytes_mapped
+= p
->bytes
;
819 p
->discarded
= false;
821 /* Recycle the allocated memory from this page ... */
825 #ifdef USING_MALLOC_PAGE_GROUPS
829 /* ... and, if possible, the page entry itself. */
830 if (p
->order
== order
)
833 memset (entry
, 0, page_entry_size
);
839 else if (entry_size
== G
.pagesize
)
841 /* We want just one page. Allocate a bunch of them and put the
842 extras on the freelist. (Can only do this optimization with
843 mmap for backing store.) */
844 struct page_entry
*e
, *f
= G
.free_pages
;
845 int i
, entries
= GGC_QUIRE_SIZE
;
847 page
= alloc_anon (NULL
, G
.pagesize
* GGC_QUIRE_SIZE
, false);
850 page
= alloc_anon (NULL
, G
.pagesize
, true);
854 /* This loop counts down so that the chain will be in ascending
856 for (i
= entries
- 1; i
>= 1; i
--)
858 e
= XCNEWVAR (struct page_entry
, page_entry_size
);
860 e
->bytes
= G
.pagesize
;
861 e
->page
= page
+ (i
<< G
.lg_pagesize
);
869 page
= alloc_anon (NULL
, entry_size
, true);
871 #ifdef USING_MALLOC_PAGE_GROUPS
874 /* Allocate a large block of memory and serve out the aligned
875 pages therein. This results in much less memory wastage
876 than the traditional implementation of valloc. */
878 char *allocation
, *a
, *enda
;
879 size_t alloc_size
, head_slop
, tail_slop
;
880 int multiple_pages
= (entry_size
== G
.pagesize
);
883 alloc_size
= GGC_QUIRE_SIZE
* G
.pagesize
;
885 alloc_size
= entry_size
+ G
.pagesize
- 1;
886 allocation
= XNEWVEC (char, alloc_size
);
888 page
= (char *) (((uintptr_t) allocation
+ G
.pagesize
- 1) & -G
.pagesize
);
889 head_slop
= page
- allocation
;
891 tail_slop
= ((size_t) allocation
+ alloc_size
) & (G
.pagesize
- 1);
893 tail_slop
= alloc_size
- entry_size
- head_slop
;
894 enda
= allocation
+ alloc_size
- tail_slop
;
896 /* We allocated N pages, which are likely not aligned, leaving
897 us with N-1 usable pages. We plan to place the page_group
898 structure somewhere in the slop. */
899 if (head_slop
>= sizeof (page_group
))
900 group
= (page_group
*)page
- 1;
903 /* We magically got an aligned allocation. Too bad, we have
904 to waste a page anyway. */
908 tail_slop
+= G
.pagesize
;
910 gcc_assert (tail_slop
>= sizeof (page_group
));
911 group
= (page_group
*)enda
;
912 tail_slop
-= sizeof (page_group
);
915 /* Remember that we allocated this memory. */
916 group
->next
= G
.page_groups
;
917 group
->allocation
= allocation
;
918 group
->alloc_size
= alloc_size
;
920 G
.page_groups
= group
;
921 G
.bytes_mapped
+= alloc_size
;
923 /* If we allocated multiple pages, put the rest on the free list. */
926 struct page_entry
*e
, *f
= G
.free_pages
;
927 for (a
= enda
- G
.pagesize
; a
!= page
; a
-= G
.pagesize
)
929 e
= XCNEWVAR (struct page_entry
, page_entry_size
);
931 e
->bytes
= G
.pagesize
;
943 entry
= XCNEWVAR (struct page_entry
, page_entry_size
);
945 entry
->bytes
= entry_size
;
947 entry
->context_depth
= G
.context_depth
;
948 entry
->order
= order
;
949 entry
->num_free_objects
= num_objects
;
950 entry
->next_bit_hint
= 1;
952 G
.context_depth_allocations
|= (unsigned long)1 << G
.context_depth
;
954 #ifdef USING_MALLOC_PAGE_GROUPS
955 entry
->group
= group
;
956 set_page_group_in_use (group
, page
);
959 /* Set the one-past-the-end in-use bit. This acts as a sentry as we
960 increment the hint. */
961 entry
->in_use_p
[num_objects
/ HOST_BITS_PER_LONG
]
962 = (unsigned long) 1 << (num_objects
% HOST_BITS_PER_LONG
);
964 set_page_table_entry (page
, entry
);
966 if (GGC_DEBUG_LEVEL
>= 2)
967 fprintf (G
.debug_file
,
968 "Allocating page at %p, object size=%lu, data %p-%p\n",
969 (void *) entry
, (unsigned long) OBJECT_SIZE (order
), page
,
970 page
+ entry_size
- 1);
975 /* Adjust the size of G.depth so that no index greater than the one
976 used by the top of the G.by_depth is used. */
983 if (G
.by_depth_in_use
)
985 top
= G
.by_depth
[G
.by_depth_in_use
-1];
987 /* Peel back indices in depth that index into by_depth, so that
988 as new elements are added to by_depth, we note the indices
989 of those elements, if they are for new context depths. */
990 while (G
.depth_in_use
> (size_t)top
->context_depth
+1)
995 /* For a page that is no longer needed, put it on the free page list. */
998 free_page (page_entry
*entry
)
1000 if (GGC_DEBUG_LEVEL
>= 2)
1001 fprintf (G
.debug_file
,
1002 "Deallocating page at %p, data %p-%p\n", (void *) entry
,
1003 entry
->page
, entry
->page
+ entry
->bytes
- 1);
1005 /* Mark the page as inaccessible. Discard the handle to avoid handle
1007 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (entry
->page
, entry
->bytes
));
1009 set_page_table_entry (entry
->page
, NULL
);
1011 #ifdef USING_MALLOC_PAGE_GROUPS
1012 clear_page_group_in_use (entry
->group
, entry
->page
);
1015 if (G
.by_depth_in_use
> 1)
1017 page_entry
*top
= G
.by_depth
[G
.by_depth_in_use
-1];
1018 int i
= entry
->index_by_depth
;
1020 /* We cannot free a page from a context deeper than the current
1022 gcc_assert (entry
->context_depth
== top
->context_depth
);
1024 /* Put top element into freed slot. */
1025 G
.by_depth
[i
] = top
;
1026 G
.save_in_use
[i
] = G
.save_in_use
[G
.by_depth_in_use
-1];
1027 top
->index_by_depth
= i
;
1029 --G
.by_depth_in_use
;
1033 entry
->next
= G
.free_pages
;
1034 G
.free_pages
= entry
;
1037 /* Release the free page cache to the system. */
1040 release_pages (void)
1042 #ifdef USING_MADVISE
1043 page_entry
*p
, *start_p
;
1047 page_entry
*next
, *prev
, *newprev
;
1048 size_t free_unit
= (GGC_QUIRE_SIZE
/2) * G
.pagesize
;
1050 /* First free larger continuous areas to the OS.
1051 This allows other allocators to grab these areas if needed.
1052 This is only done on larger chunks to avoid fragmentation.
1053 This does not always work because the free_pages list is only
1054 approximately sorted. */
1065 while (p
&& p
->page
== start
+ len
)
1069 mapped_len
+= p
->bytes
;
1073 if (len
>= free_unit
)
1075 while (start_p
!= p
)
1077 next
= start_p
->next
;
1081 munmap (start
, len
);
1086 G
.bytes_mapped
-= mapped_len
;
1092 /* Now give back the fragmented pages to the OS, but keep the address
1093 space to reuse it next time. */
1095 for (p
= G
.free_pages
; p
; )
1106 while (p
&& p
->page
== start
+ len
)
1111 /* Give the page back to the kernel, but don't free the mapping.
1112 This avoids fragmentation in the virtual memory map of the
1113 process. Next time we can reuse it by just touching it. */
1114 madvise (start
, len
, MADV_DONTNEED
);
1115 /* Don't count those pages as mapped to not touch the garbage collector
1117 G
.bytes_mapped
-= len
;
1118 while (start_p
!= p
)
1120 start_p
->discarded
= true;
1121 start_p
= start_p
->next
;
1125 #if defined(USING_MMAP) && !defined(USING_MADVISE)
1126 page_entry
*p
, *next
;
1130 /* Gather up adjacent pages so they are unmapped together. */
1141 while (p
&& p
->page
== start
+ len
)
1149 munmap (start
, len
);
1150 G
.bytes_mapped
-= len
;
1153 G
.free_pages
= NULL
;
1155 #ifdef USING_MALLOC_PAGE_GROUPS
1156 page_entry
**pp
, *p
;
1157 page_group
**gp
, *g
;
1159 /* Remove all pages from free page groups from the list. */
1161 while ((p
= *pp
) != NULL
)
1162 if (p
->group
->in_use
== 0)
1170 /* Remove all free page groups, and release the storage. */
1171 gp
= &G
.page_groups
;
1172 while ((g
= *gp
) != NULL
)
1176 G
.bytes_mapped
-= g
->alloc_size
;
1177 free (g
->allocation
);
1184 /* This table provides a fast way to determine ceil(log_2(size)) for
1185 allocation requests. The minimum allocation size is eight bytes. */
1186 #define NUM_SIZE_LOOKUP 512
1187 static unsigned char size_lookup
[NUM_SIZE_LOOKUP
] =
1189 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4,
1190 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
1191 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
1192 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
1193 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1194 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1195 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1196 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1197 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1198 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1199 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1200 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1201 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1202 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1203 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1204 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1205 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1206 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1207 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1208 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1209 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1210 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1211 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1212 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1213 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1214 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1215 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1216 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1217 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1218 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1219 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1220 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9
1223 /* For a given size of memory requested for allocation, return the
1224 actual size that is going to be allocated, as well as the size
1228 ggc_round_alloc_size_1 (size_t requested_size
,
1230 size_t *alloced_size
)
1232 size_t order
, object_size
;
1234 if (requested_size
< NUM_SIZE_LOOKUP
)
1236 order
= size_lookup
[requested_size
];
1237 object_size
= OBJECT_SIZE (order
);
1242 while (requested_size
> (object_size
= OBJECT_SIZE (order
)))
1247 *size_order
= order
;
1249 *alloced_size
= object_size
;
1252 /* For a given size of memory requested for allocation, return the
1253 actual size that is going to be allocated. */
1256 ggc_round_alloc_size (size_t requested_size
)
1260 ggc_round_alloc_size_1 (requested_size
, NULL
, &size
);
1264 /* Allocate a chunk of memory of SIZE bytes. Its contents are undefined. */
1267 ggc_internal_alloc (size_t size
, void (*f
)(void *), size_t s
, size_t n
1270 size_t order
, word
, bit
, object_offset
, object_size
;
1271 struct page_entry
*entry
;
1274 ggc_round_alloc_size_1 (size
, &order
, &object_size
);
1276 /* If there are non-full pages for this size allocation, they are at
1277 the head of the list. */
1278 entry
= G
.pages
[order
];
1280 /* If there is no page for this object size, or all pages in this
1281 context are full, allocate a new page. */
1282 if (entry
== NULL
|| entry
->num_free_objects
== 0)
1284 struct page_entry
*new_entry
;
1285 new_entry
= alloc_page (order
);
1287 new_entry
->index_by_depth
= G
.by_depth_in_use
;
1288 push_by_depth (new_entry
, 0);
1290 /* We can skip context depths, if we do, make sure we go all the
1291 way to the new depth. */
1292 while (new_entry
->context_depth
>= G
.depth_in_use
)
1293 push_depth (G
.by_depth_in_use
-1);
1295 /* If this is the only entry, it's also the tail. If it is not
1296 the only entry, then we must update the PREV pointer of the
1297 ENTRY (G.pages[order]) to point to our new page entry. */
1299 G
.page_tails
[order
] = new_entry
;
1301 entry
->prev
= new_entry
;
1303 /* Put new pages at the head of the page list. By definition the
1304 entry at the head of the list always has a NULL pointer. */
1305 new_entry
->next
= entry
;
1306 new_entry
->prev
= NULL
;
1308 G
.pages
[order
] = new_entry
;
1310 /* For a new page, we know the word and bit positions (in the
1311 in_use bitmap) of the first available object -- they're zero. */
1312 new_entry
->next_bit_hint
= 1;
1319 /* First try to use the hint left from the previous allocation
1320 to locate a clear bit in the in-use bitmap. We've made sure
1321 that the one-past-the-end bit is always set, so if the hint
1322 has run over, this test will fail. */
1323 unsigned hint
= entry
->next_bit_hint
;
1324 word
= hint
/ HOST_BITS_PER_LONG
;
1325 bit
= hint
% HOST_BITS_PER_LONG
;
1327 /* If the hint didn't work, scan the bitmap from the beginning. */
1328 if ((entry
->in_use_p
[word
] >> bit
) & 1)
1331 while (~entry
->in_use_p
[word
] == 0)
1334 #if GCC_VERSION >= 3004
1335 bit
= __builtin_ctzl (~entry
->in_use_p
[word
]);
1337 while ((entry
->in_use_p
[word
] >> bit
) & 1)
1341 hint
= word
* HOST_BITS_PER_LONG
+ bit
;
1344 /* Next time, try the next bit. */
1345 entry
->next_bit_hint
= hint
+ 1;
1347 object_offset
= hint
* object_size
;
1350 /* Set the in-use bit. */
1351 entry
->in_use_p
[word
] |= ((unsigned long) 1 << bit
);
1353 /* Keep a running total of the number of free objects. If this page
1354 fills up, we may have to move it to the end of the list if the
1355 next page isn't full. If the next page is full, all subsequent
1356 pages are full, so there's no need to move it. */
1357 if (--entry
->num_free_objects
== 0
1358 && entry
->next
!= NULL
1359 && entry
->next
->num_free_objects
> 0)
1361 /* We have a new head for the list. */
1362 G
.pages
[order
] = entry
->next
;
1364 /* We are moving ENTRY to the end of the page table list.
1365 The new page at the head of the list will have NULL in
1366 its PREV field and ENTRY will have NULL in its NEXT field. */
1367 entry
->next
->prev
= NULL
;
1370 /* Append ENTRY to the tail of the list. */
1371 entry
->prev
= G
.page_tails
[order
];
1372 G
.page_tails
[order
]->next
= entry
;
1373 G
.page_tails
[order
] = entry
;
1376 /* Calculate the object's address. */
1377 result
= entry
->page
+ object_offset
;
1378 if (GATHER_STATISTICS
)
1379 ggc_record_overhead (OBJECT_SIZE (order
), OBJECT_SIZE (order
) - size
,
1380 result FINAL_PASS_MEM_STAT
);
1382 #ifdef ENABLE_GC_CHECKING
1383 /* Keep poisoning-by-writing-0xaf the object, in an attempt to keep the
1384 exact same semantics in presence of memory bugs, regardless of
1385 ENABLE_VALGRIND_CHECKING. We override this request below. Drop the
1386 handle to avoid handle leak. */
1387 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (result
, object_size
));
1389 /* `Poison' the entire allocated object, including any padding at
1391 memset (result
, 0xaf, object_size
);
1393 /* Make the bytes after the end of the object unaccessible. Discard the
1394 handle to avoid handle leak. */
1395 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS ((char *) result
+ size
,
1396 object_size
- size
));
1399 /* Tell Valgrind that the memory is there, but its content isn't
1400 defined. The bytes at the end of the object are still marked
1402 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (result
, size
));
1404 /* Keep track of how many bytes are being allocated. This
1405 information is used in deciding when to collect. */
1406 G
.allocated
+= object_size
;
1408 /* For timevar statistics. */
1409 timevar_ggc_mem_total
+= object_size
;
1412 G
.finalizers
.safe_push (finalizer (result
, f
));
1414 G
.vec_finalizers
.safe_push
1415 (vec_finalizer (reinterpret_cast<uintptr_t> (result
), f
, s
, n
));
1417 if (GATHER_STATISTICS
)
1419 size_t overhead
= object_size
- size
;
1421 G
.stats
.total_overhead
+= overhead
;
1422 G
.stats
.total_allocated
+= object_size
;
1423 G
.stats
.total_overhead_per_order
[order
] += overhead
;
1424 G
.stats
.total_allocated_per_order
[order
] += object_size
;
1428 G
.stats
.total_overhead_under32
+= overhead
;
1429 G
.stats
.total_allocated_under32
+= object_size
;
1433 G
.stats
.total_overhead_under64
+= overhead
;
1434 G
.stats
.total_allocated_under64
+= object_size
;
1438 G
.stats
.total_overhead_under128
+= overhead
;
1439 G
.stats
.total_allocated_under128
+= object_size
;
1443 if (GGC_DEBUG_LEVEL
>= 3)
1444 fprintf (G
.debug_file
,
1445 "Allocating object, requested size=%lu, actual=%lu at %p on %p\n",
1446 (unsigned long) size
, (unsigned long) object_size
, result
,
1452 /* Mark function for strings. */
1455 gt_ggc_m_S (const void *p
)
1460 unsigned long offset
;
1462 if (!p
|| !ggc_allocated_p (p
))
1465 /* Look up the page on which the object is alloced. . */
1466 entry
= lookup_page_table_entry (p
);
1469 /* Calculate the index of the object on the page; this is its bit
1470 position in the in_use_p bitmap. Note that because a char* might
1471 point to the middle of an object, we need special code here to
1472 make sure P points to the start of an object. */
1473 offset
= ((const char *) p
- entry
->page
) % object_size_table
[entry
->order
];
1476 /* Here we've seen a char* which does not point to the beginning
1477 of an allocated object. We assume it points to the middle of
1479 gcc_assert (offset
== offsetof (struct tree_string
, str
));
1480 p
= ((const char *) p
) - offset
;
1481 gt_ggc_mx_lang_tree_node (CONST_CAST (void *, p
));
1485 bit
= OFFSET_TO_BIT (((const char *) p
) - entry
->page
, entry
->order
);
1486 word
= bit
/ HOST_BITS_PER_LONG
;
1487 mask
= (unsigned long) 1 << (bit
% HOST_BITS_PER_LONG
);
1489 /* If the bit was previously set, skip it. */
1490 if (entry
->in_use_p
[word
] & mask
)
1493 /* Otherwise set it, and decrement the free object count. */
1494 entry
->in_use_p
[word
] |= mask
;
1495 entry
->num_free_objects
-= 1;
1497 if (GGC_DEBUG_LEVEL
>= 4)
1498 fprintf (G
.debug_file
, "Marking %p\n", p
);
1504 /* User-callable entry points for marking string X. */
1507 gt_ggc_mx (const char *& x
)
1513 gt_ggc_mx (unsigned char *& x
)
1519 gt_ggc_mx (unsigned char& x ATTRIBUTE_UNUSED
)
1523 /* If P is not marked, marks it and return false. Otherwise return true.
1524 P must have been allocated by the GC allocator; it mustn't point to
1525 static objects, stack variables, or memory allocated with malloc. */
1528 ggc_set_mark (const void *p
)
1534 /* Look up the page on which the object is alloced. If the object
1535 wasn't allocated by the collector, we'll probably die. */
1536 entry
= lookup_page_table_entry (p
);
1539 /* Calculate the index of the object on the page; this is its bit
1540 position in the in_use_p bitmap. */
1541 bit
= OFFSET_TO_BIT (((const char *) p
) - entry
->page
, entry
->order
);
1542 word
= bit
/ HOST_BITS_PER_LONG
;
1543 mask
= (unsigned long) 1 << (bit
% HOST_BITS_PER_LONG
);
1545 /* If the bit was previously set, skip it. */
1546 if (entry
->in_use_p
[word
] & mask
)
1549 /* Otherwise set it, and decrement the free object count. */
1550 entry
->in_use_p
[word
] |= mask
;
1551 entry
->num_free_objects
-= 1;
1553 if (GGC_DEBUG_LEVEL
>= 4)
1554 fprintf (G
.debug_file
, "Marking %p\n", p
);
1559 /* Return 1 if P has been marked, zero otherwise.
1560 P must have been allocated by the GC allocator; it mustn't point to
1561 static objects, stack variables, or memory allocated with malloc. */
1564 ggc_marked_p (const void *p
)
1570 /* Look up the page on which the object is alloced. If the object
1571 wasn't allocated by the collector, we'll probably die. */
1572 entry
= lookup_page_table_entry (p
);
1575 /* Calculate the index of the object on the page; this is its bit
1576 position in the in_use_p bitmap. */
1577 bit
= OFFSET_TO_BIT (((const char *) p
) - entry
->page
, entry
->order
);
1578 word
= bit
/ HOST_BITS_PER_LONG
;
1579 mask
= (unsigned long) 1 << (bit
% HOST_BITS_PER_LONG
);
1581 return (entry
->in_use_p
[word
] & mask
) != 0;
1584 /* Return the size of the gc-able object P. */
1587 ggc_get_size (const void *p
)
1589 page_entry
*pe
= lookup_page_table_entry (p
);
1590 return OBJECT_SIZE (pe
->order
);
1593 /* Release the memory for object P. */
1601 page_entry
*pe
= lookup_page_table_entry (p
);
1602 size_t order
= pe
->order
;
1603 size_t size
= OBJECT_SIZE (order
);
1605 if (GATHER_STATISTICS
)
1606 ggc_free_overhead (p
);
1608 if (GGC_DEBUG_LEVEL
>= 3)
1609 fprintf (G
.debug_file
,
1610 "Freeing object, actual size=%lu, at %p on %p\n",
1611 (unsigned long) size
, p
, (void *) pe
);
1613 #ifdef ENABLE_GC_CHECKING
1614 /* Poison the data, to indicate the data is garbage. */
1615 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (p
, size
));
1616 memset (p
, 0xa5, size
);
1618 /* Let valgrind know the object is free. */
1619 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (p
, size
));
1621 #ifdef ENABLE_GC_ALWAYS_COLLECT
1622 /* In the completely-anal-checking mode, we do *not* immediately free
1623 the data, but instead verify that the data is *actually* not
1624 reachable the next time we collect. */
1626 struct free_object
*fo
= XNEW (struct free_object
);
1628 fo
->next
= G
.free_object_list
;
1629 G
.free_object_list
= fo
;
1633 unsigned int bit_offset
, word
, bit
;
1635 G
.allocated
-= size
;
1637 /* Mark the object not-in-use. */
1638 bit_offset
= OFFSET_TO_BIT (((const char *) p
) - pe
->page
, order
);
1639 word
= bit_offset
/ HOST_BITS_PER_LONG
;
1640 bit
= bit_offset
% HOST_BITS_PER_LONG
;
1641 pe
->in_use_p
[word
] &= ~(1UL << bit
);
1643 if (pe
->num_free_objects
++ == 0)
1647 /* If the page is completely full, then it's supposed to
1648 be after all pages that aren't. Since we've freed one
1649 object from a page that was full, we need to move the
1650 page to the head of the list.
1652 PE is the node we want to move. Q is the previous node
1653 and P is the next node in the list. */
1655 if (q
&& q
->num_free_objects
== 0)
1661 /* If PE was at the end of the list, then Q becomes the
1662 new end of the list. If PE was not the end of the
1663 list, then we need to update the PREV field for P. */
1665 G
.page_tails
[order
] = q
;
1669 /* Move PE to the head of the list. */
1670 pe
->next
= G
.pages
[order
];
1672 G
.pages
[order
]->prev
= pe
;
1673 G
.pages
[order
] = pe
;
1676 /* Reset the hint bit to point to the only free object. */
1677 pe
->next_bit_hint
= bit_offset
;
1683 /* Subroutine of init_ggc which computes the pair of numbers used to
1684 perform division by OBJECT_SIZE (order) and fills in inverse_table[].
1686 This algorithm is taken from Granlund and Montgomery's paper
1687 "Division by Invariant Integers using Multiplication"
1688 (Proc. SIGPLAN PLDI, 1994), section 9 (Exact division by
1692 compute_inverse (unsigned order
)
1697 size
= OBJECT_SIZE (order
);
1699 while (size
% 2 == 0)
1706 while (inv
* size
!= 1)
1707 inv
= inv
* (2 - inv
*size
);
1709 DIV_MULT (order
) = inv
;
1710 DIV_SHIFT (order
) = e
;
1713 /* Initialize the ggc-mmap allocator. */
1717 static bool init_p
= false;
1724 G
.pagesize
= getpagesize ();
1725 G
.lg_pagesize
= exact_log2 (G
.pagesize
);
1727 #ifdef HAVE_MMAP_DEV_ZERO
1728 G
.dev_zero_fd
= open ("/dev/zero", O_RDONLY
);
1729 if (G
.dev_zero_fd
== -1)
1730 internal_error ("open /dev/zero: %m");
1734 G
.debug_file
= fopen ("ggc-mmap.debug", "w");
1736 G
.debug_file
= stdout
;
1740 /* StunOS has an amazing off-by-one error for the first mmap allocation
1741 after fiddling with RLIMIT_STACK. The result, as hard as it is to
1742 believe, is an unaligned page allocation, which would cause us to
1743 hork badly if we tried to use it. */
1745 char *p
= alloc_anon (NULL
, G
.pagesize
, true);
1746 struct page_entry
*e
;
1747 if ((uintptr_t)p
& (G
.pagesize
- 1))
1749 /* How losing. Discard this one and try another. If we still
1750 can't get something useful, give up. */
1752 p
= alloc_anon (NULL
, G
.pagesize
, true);
1753 gcc_assert (!((uintptr_t)p
& (G
.pagesize
- 1)));
1756 /* We have a good page, might as well hold onto it... */
1757 e
= XCNEW (struct page_entry
);
1758 e
->bytes
= G
.pagesize
;
1760 e
->next
= G
.free_pages
;
1765 /* Initialize the object size table. */
1766 for (order
= 0; order
< HOST_BITS_PER_PTR
; ++order
)
1767 object_size_table
[order
] = (size_t) 1 << order
;
1768 for (order
= HOST_BITS_PER_PTR
; order
< NUM_ORDERS
; ++order
)
1770 size_t s
= extra_order_size_table
[order
- HOST_BITS_PER_PTR
];
1772 /* If S is not a multiple of the MAX_ALIGNMENT, then round it up
1773 so that we're sure of getting aligned memory. */
1774 s
= ROUND_UP (s
, MAX_ALIGNMENT
);
1775 object_size_table
[order
] = s
;
1778 /* Initialize the objects-per-page and inverse tables. */
1779 for (order
= 0; order
< NUM_ORDERS
; ++order
)
1781 objects_per_page_table
[order
] = G
.pagesize
/ OBJECT_SIZE (order
);
1782 if (objects_per_page_table
[order
] == 0)
1783 objects_per_page_table
[order
] = 1;
1784 compute_inverse (order
);
1787 /* Reset the size_lookup array to put appropriately sized objects in
1788 the special orders. All objects bigger than the previous power
1789 of two, but no greater than the special size, should go in the
1791 for (order
= HOST_BITS_PER_PTR
; order
< NUM_ORDERS
; ++order
)
1796 i
= OBJECT_SIZE (order
);
1797 if (i
>= NUM_SIZE_LOOKUP
)
1800 for (o
= size_lookup
[i
]; o
== size_lookup
[i
]; --i
)
1801 size_lookup
[i
] = order
;
1806 G
.depth
= XNEWVEC (unsigned int, G
.depth_max
);
1808 G
.by_depth_in_use
= 0;
1809 G
.by_depth_max
= INITIAL_PTE_COUNT
;
1810 G
.by_depth
= XNEWVEC (page_entry
*, G
.by_depth_max
);
1811 G
.save_in_use
= XNEWVEC (unsigned long *, G
.by_depth_max
);
1814 /* Merge the SAVE_IN_USE_P and IN_USE_P arrays in P so that IN_USE_P
1815 reflects reality. Recalculate NUM_FREE_OBJECTS as well. */
1818 ggc_recalculate_in_use_p (page_entry
*p
)
1823 /* Because the past-the-end bit in in_use_p is always set, we
1824 pretend there is one additional object. */
1825 num_objects
= OBJECTS_IN_PAGE (p
) + 1;
1827 /* Reset the free object count. */
1828 p
->num_free_objects
= num_objects
;
1830 /* Combine the IN_USE_P and SAVE_IN_USE_P arrays. */
1832 i
< CEIL (BITMAP_SIZE (num_objects
),
1833 sizeof (*p
->in_use_p
));
1838 /* Something is in use if it is marked, or if it was in use in a
1839 context further down the context stack. */
1840 p
->in_use_p
[i
] |= save_in_use_p (p
)[i
];
1842 /* Decrement the free object count for every object allocated. */
1843 for (j
= p
->in_use_p
[i
]; j
; j
>>= 1)
1844 p
->num_free_objects
-= (j
& 1);
1847 gcc_assert (p
->num_free_objects
< num_objects
);
1850 /* Unmark all objects. */
1857 for (order
= 2; order
< NUM_ORDERS
; order
++)
1861 for (p
= G
.pages
[order
]; p
!= NULL
; p
= p
->next
)
1863 size_t num_objects
= OBJECTS_IN_PAGE (p
);
1864 size_t bitmap_size
= BITMAP_SIZE (num_objects
+ 1);
1866 /* The data should be page-aligned. */
1867 gcc_assert (!((uintptr_t) p
->page
& (G
.pagesize
- 1)));
1869 /* Pages that aren't in the topmost context are not collected;
1870 nevertheless, we need their in-use bit vectors to store GC
1871 marks. So, back them up first. */
1872 if (p
->context_depth
< G
.context_depth
)
1874 if (! save_in_use_p (p
))
1875 save_in_use_p (p
) = XNEWVAR (unsigned long, bitmap_size
);
1876 memcpy (save_in_use_p (p
), p
->in_use_p
, bitmap_size
);
1879 /* Reset reset the number of free objects and clear the
1880 in-use bits. These will be adjusted by mark_obj. */
1881 p
->num_free_objects
= num_objects
;
1882 memset (p
->in_use_p
, 0, bitmap_size
);
1884 /* Make sure the one-past-the-end bit is always set. */
1885 p
->in_use_p
[num_objects
/ HOST_BITS_PER_LONG
]
1886 = ((unsigned long) 1 << (num_objects
% HOST_BITS_PER_LONG
));
1891 /* Check if any blocks with a registered finalizer have become unmarked. If so
1892 run the finalizer and unregister it because the block is about to be freed.
1893 Note that no garantee is made about what order finalizers will run in so
1894 touching other objects in gc memory is extremely unwise. */
1897 ggc_handle_finalizers ()
1899 if (G
.context_depth
!= 0)
1902 unsigned length
= G
.finalizers
.length ();
1903 for (unsigned int i
= 0; i
< length
;)
1905 finalizer
&f
= G
.finalizers
[i
];
1906 if (!ggc_marked_p (f
.addr ()))
1909 G
.finalizers
.unordered_remove (i
);
1917 length
= G
.vec_finalizers
.length ();
1918 for (unsigned int i
= 0; i
< length
;)
1920 vec_finalizer
&f
= G
.vec_finalizers
[i
];
1921 if (!ggc_marked_p (f
.addr ()))
1924 G
.vec_finalizers
.unordered_remove (i
);
1932 /* Free all empty pages. Partially empty pages need no attention
1933 because the `mark' bit doubles as an `unused' bit. */
1940 for (order
= 2; order
< NUM_ORDERS
; order
++)
1942 /* The last page-entry to consider, regardless of entries
1943 placed at the end of the list. */
1944 page_entry
* const last
= G
.page_tails
[order
];
1947 size_t live_objects
;
1948 page_entry
*p
, *previous
;
1958 page_entry
*next
= p
->next
;
1960 /* Loop until all entries have been examined. */
1963 num_objects
= OBJECTS_IN_PAGE (p
);
1965 /* Add all live objects on this page to the count of
1966 allocated memory. */
1967 live_objects
= num_objects
- p
->num_free_objects
;
1969 G
.allocated
+= OBJECT_SIZE (order
) * live_objects
;
1971 /* Only objects on pages in the topmost context should get
1973 if (p
->context_depth
< G
.context_depth
)
1976 /* Remove the page if it's empty. */
1977 else if (live_objects
== 0)
1979 /* If P was the first page in the list, then NEXT
1980 becomes the new first page in the list, otherwise
1981 splice P out of the forward pointers. */
1983 G
.pages
[order
] = next
;
1985 previous
->next
= next
;
1987 /* Splice P out of the back pointers too. */
1989 next
->prev
= previous
;
1991 /* Are we removing the last element? */
1992 if (p
== G
.page_tails
[order
])
1993 G
.page_tails
[order
] = previous
;
1998 /* If the page is full, move it to the end. */
1999 else if (p
->num_free_objects
== 0)
2001 /* Don't move it if it's already at the end. */
2002 if (p
!= G
.page_tails
[order
])
2004 /* Move p to the end of the list. */
2006 p
->prev
= G
.page_tails
[order
];
2007 G
.page_tails
[order
]->next
= p
;
2009 /* Update the tail pointer... */
2010 G
.page_tails
[order
] = p
;
2012 /* ... and the head pointer, if necessary. */
2014 G
.pages
[order
] = next
;
2016 previous
->next
= next
;
2018 /* And update the backpointer in NEXT if necessary. */
2020 next
->prev
= previous
;
2026 /* If we've fallen through to here, it's a page in the
2027 topmost context that is neither full nor empty. Such a
2028 page must precede pages at lesser context depth in the
2029 list, so move it to the head. */
2030 else if (p
!= G
.pages
[order
])
2032 previous
->next
= p
->next
;
2034 /* Update the backchain in the next node if it exists. */
2036 p
->next
->prev
= previous
;
2038 /* Move P to the head of the list. */
2039 p
->next
= G
.pages
[order
];
2041 G
.pages
[order
]->prev
= p
;
2043 /* Update the head pointer. */
2046 /* Are we moving the last element? */
2047 if (G
.page_tails
[order
] == p
)
2048 G
.page_tails
[order
] = previous
;
2057 /* Now, restore the in_use_p vectors for any pages from contexts
2058 other than the current one. */
2059 for (p
= G
.pages
[order
]; p
; p
= p
->next
)
2060 if (p
->context_depth
!= G
.context_depth
)
2061 ggc_recalculate_in_use_p (p
);
2065 #ifdef ENABLE_GC_CHECKING
2066 /* Clobber all free objects. */
2073 for (order
= 2; order
< NUM_ORDERS
; order
++)
2075 size_t size
= OBJECT_SIZE (order
);
2078 for (p
= G
.pages
[order
]; p
!= NULL
; p
= p
->next
)
2083 if (p
->context_depth
!= G
.context_depth
)
2084 /* Since we don't do any collection for pages in pushed
2085 contexts, there's no need to do any poisoning. And
2086 besides, the IN_USE_P array isn't valid until we pop
2090 num_objects
= OBJECTS_IN_PAGE (p
);
2091 for (i
= 0; i
< num_objects
; i
++)
2094 word
= i
/ HOST_BITS_PER_LONG
;
2095 bit
= i
% HOST_BITS_PER_LONG
;
2096 if (((p
->in_use_p
[word
] >> bit
) & 1) == 0)
2098 char *object
= p
->page
+ i
* size
;
2100 /* Keep poison-by-write when we expect to use Valgrind,
2101 so the exact same memory semantics is kept, in case
2102 there are memory errors. We override this request
2104 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (object
,
2106 memset (object
, 0xa5, size
);
2108 /* Drop the handle to avoid handle leak. */
2109 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (object
, size
));
2116 #define poison_pages()
2119 #ifdef ENABLE_GC_ALWAYS_COLLECT
2120 /* Validate that the reportedly free objects actually are. */
2123 validate_free_objects (void)
2125 struct free_object
*f
, *next
, *still_free
= NULL
;
2127 for (f
= G
.free_object_list
; f
; f
= next
)
2129 page_entry
*pe
= lookup_page_table_entry (f
->object
);
2132 bit
= OFFSET_TO_BIT ((char *)f
->object
- pe
->page
, pe
->order
);
2133 word
= bit
/ HOST_BITS_PER_LONG
;
2134 bit
= bit
% HOST_BITS_PER_LONG
;
2137 /* Make certain it isn't visible from any root. Notice that we
2138 do this check before sweep_pages merges save_in_use_p. */
2139 gcc_assert (!(pe
->in_use_p
[word
] & (1UL << bit
)));
2141 /* If the object comes from an outer context, then retain the
2142 free_object entry, so that we can verify that the address
2143 isn't live on the stack in some outer context. */
2144 if (pe
->context_depth
!= G
.context_depth
)
2146 f
->next
= still_free
;
2153 G
.free_object_list
= still_free
;
2156 #define validate_free_objects()
2159 /* Top level mark-and-sweep routine. */
2164 /* Avoid frequent unnecessary work by skipping collection if the
2165 total allocations haven't expanded much since the last
2167 float allocated_last_gc
=
2168 MAX (G
.allocated_last_gc
, (size_t)PARAM_VALUE (GGC_MIN_HEAPSIZE
) * 1024);
2170 float min_expand
= allocated_last_gc
* PARAM_VALUE (GGC_MIN_EXPAND
) / 100;
2171 if (G
.allocated
< allocated_last_gc
+ min_expand
&& !ggc_force_collect
)
2174 timevar_push (TV_GC
);
2176 fprintf (stderr
, " {GC %luk -> ", (unsigned long) G
.allocated
/ 1024);
2177 if (GGC_DEBUG_LEVEL
>= 2)
2178 fprintf (G
.debug_file
, "BEGIN COLLECTING\n");
2180 /* Zero the total allocated bytes. This will be recalculated in the
2184 /* Release the pages we freed the last time we collected, but didn't
2185 reuse in the interim. */
2188 /* Indicate that we've seen collections at this context depth. */
2189 G
.context_depth_collections
= ((unsigned long)1 << (G
.context_depth
+ 1)) - 1;
2191 invoke_plugin_callbacks (PLUGIN_GGC_START
, NULL
);
2196 ggc_handle_finalizers ();
2198 if (GATHER_STATISTICS
)
2199 ggc_prune_overhead_list ();
2202 validate_free_objects ();
2206 G
.allocated_last_gc
= G
.allocated
;
2208 invoke_plugin_callbacks (PLUGIN_GGC_END
, NULL
);
2210 timevar_pop (TV_GC
);
2213 fprintf (stderr
, "%luk}", (unsigned long) G
.allocated
/ 1024);
2214 if (GGC_DEBUG_LEVEL
>= 2)
2215 fprintf (G
.debug_file
, "END COLLECTING\n");
2218 /* Assume that all GGC memory is reachable and grow the limits for next collection.
2219 With checking, trigger GGC so -Q compilation outputs how much of memory really is
2225 #ifndef ENABLE_CHECKING
2226 G
.allocated_last_gc
= MAX (G
.allocated_last_gc
,
2232 fprintf (stderr
, " {GC start %luk} ", (unsigned long) G
.allocated
/ 1024);
2235 /* Print allocation statistics. */
2236 #define SCALE(x) ((unsigned long) ((x) < 1024*10 \
2238 : ((x) < 1024*1024*10 \
2240 : (x) / (1024*1024))))
2241 #define STAT_LABEL(x) ((x) < 1024*10 ? ' ' : ((x) < 1024*1024*10 ? 'k' : 'M'))
2244 ggc_print_statistics (void)
2246 struct ggc_statistics stats
;
2248 size_t total_overhead
= 0;
2250 /* Clear the statistics. */
2251 memset (&stats
, 0, sizeof (stats
));
2253 /* Make sure collection will really occur. */
2254 G
.allocated_last_gc
= 0;
2256 /* Collect and print the statistics common across collectors. */
2257 ggc_print_common_statistics (stderr
, &stats
);
2259 /* Release free pages so that we will not count the bytes allocated
2260 there as part of the total allocated memory. */
2263 /* Collect some information about the various sizes of
2266 "Memory still allocated at the end of the compilation process\n");
2267 fprintf (stderr
, "%-8s %10s %10s %10s\n",
2268 "Size", "Allocated", "Used", "Overhead");
2269 for (i
= 0; i
< NUM_ORDERS
; ++i
)
2276 /* Skip empty entries. */
2280 overhead
= allocated
= in_use
= 0;
2282 /* Figure out the total number of bytes allocated for objects of
2283 this size, and how many of them are actually in use. Also figure
2284 out how much memory the page table is using. */
2285 for (p
= G
.pages
[i
]; p
; p
= p
->next
)
2287 allocated
+= p
->bytes
;
2289 (OBJECTS_IN_PAGE (p
) - p
->num_free_objects
) * OBJECT_SIZE (i
);
2291 overhead
+= (sizeof (page_entry
) - sizeof (long)
2292 + BITMAP_SIZE (OBJECTS_IN_PAGE (p
) + 1));
2294 fprintf (stderr
, "%-8lu %10lu%c %10lu%c %10lu%c\n",
2295 (unsigned long) OBJECT_SIZE (i
),
2296 SCALE (allocated
), STAT_LABEL (allocated
),
2297 SCALE (in_use
), STAT_LABEL (in_use
),
2298 SCALE (overhead
), STAT_LABEL (overhead
));
2299 total_overhead
+= overhead
;
2301 fprintf (stderr
, "%-8s %10lu%c %10lu%c %10lu%c\n", "Total",
2302 SCALE (G
.bytes_mapped
), STAT_LABEL (G
.bytes_mapped
),
2303 SCALE (G
.allocated
), STAT_LABEL (G
.allocated
),
2304 SCALE (total_overhead
), STAT_LABEL (total_overhead
));
2306 if (GATHER_STATISTICS
)
2308 fprintf (stderr
, "\nTotal allocations and overheads during "
2309 "the compilation process\n");
2311 fprintf (stderr
, "Total Overhead: %10"
2312 HOST_LONG_LONG_FORMAT
"d\n", G
.stats
.total_overhead
);
2313 fprintf (stderr
, "Total Allocated: %10"
2314 HOST_LONG_LONG_FORMAT
"d\n",
2315 G
.stats
.total_allocated
);
2317 fprintf (stderr
, "Total Overhead under 32B: %10"
2318 HOST_LONG_LONG_FORMAT
"d\n", G
.stats
.total_overhead_under32
);
2319 fprintf (stderr
, "Total Allocated under 32B: %10"
2320 HOST_LONG_LONG_FORMAT
"d\n", G
.stats
.total_allocated_under32
);
2321 fprintf (stderr
, "Total Overhead under 64B: %10"
2322 HOST_LONG_LONG_FORMAT
"d\n", G
.stats
.total_overhead_under64
);
2323 fprintf (stderr
, "Total Allocated under 64B: %10"
2324 HOST_LONG_LONG_FORMAT
"d\n", G
.stats
.total_allocated_under64
);
2325 fprintf (stderr
, "Total Overhead under 128B: %10"
2326 HOST_LONG_LONG_FORMAT
"d\n", G
.stats
.total_overhead_under128
);
2327 fprintf (stderr
, "Total Allocated under 128B: %10"
2328 HOST_LONG_LONG_FORMAT
"d\n", G
.stats
.total_allocated_under128
);
2330 for (i
= 0; i
< NUM_ORDERS
; i
++)
2331 if (G
.stats
.total_allocated_per_order
[i
])
2333 fprintf (stderr
, "Total Overhead page size %9lu: %10"
2334 HOST_LONG_LONG_FORMAT
"d\n",
2335 (unsigned long) OBJECT_SIZE (i
),
2336 G
.stats
.total_overhead_per_order
[i
]);
2337 fprintf (stderr
, "Total Allocated page size %9lu: %10"
2338 HOST_LONG_LONG_FORMAT
"d\n",
2339 (unsigned long) OBJECT_SIZE (i
),
2340 G
.stats
.total_allocated_per_order
[i
]);
2345 struct ggc_pch_ondisk
2347 unsigned totals
[NUM_ORDERS
];
2352 struct ggc_pch_ondisk d
;
2353 uintptr_t base
[NUM_ORDERS
];
2354 size_t written
[NUM_ORDERS
];
2357 struct ggc_pch_data
*
2360 return XCNEW (struct ggc_pch_data
);
2364 ggc_pch_count_object (struct ggc_pch_data
*d
, void *x ATTRIBUTE_UNUSED
,
2365 size_t size
, bool is_string ATTRIBUTE_UNUSED
)
2369 if (size
< NUM_SIZE_LOOKUP
)
2370 order
= size_lookup
[size
];
2374 while (size
> OBJECT_SIZE (order
))
2378 d
->d
.totals
[order
]++;
2382 ggc_pch_total_size (struct ggc_pch_data
*d
)
2387 for (i
= 0; i
< NUM_ORDERS
; i
++)
2388 a
+= PAGE_ALIGN (d
->d
.totals
[i
] * OBJECT_SIZE (i
));
2393 ggc_pch_this_base (struct ggc_pch_data
*d
, void *base
)
2395 uintptr_t a
= (uintptr_t) base
;
2398 for (i
= 0; i
< NUM_ORDERS
; i
++)
2401 a
+= PAGE_ALIGN (d
->d
.totals
[i
] * OBJECT_SIZE (i
));
2407 ggc_pch_alloc_object (struct ggc_pch_data
*d
, void *x ATTRIBUTE_UNUSED
,
2408 size_t size
, bool is_string ATTRIBUTE_UNUSED
)
2413 if (size
< NUM_SIZE_LOOKUP
)
2414 order
= size_lookup
[size
];
2418 while (size
> OBJECT_SIZE (order
))
2422 result
= (char *) d
->base
[order
];
2423 d
->base
[order
] += OBJECT_SIZE (order
);
2428 ggc_pch_prepare_write (struct ggc_pch_data
*d ATTRIBUTE_UNUSED
,
2429 FILE *f ATTRIBUTE_UNUSED
)
2431 /* Nothing to do. */
2435 ggc_pch_write_object (struct ggc_pch_data
*d
,
2436 FILE *f
, void *x
, void *newx ATTRIBUTE_UNUSED
,
2437 size_t size
, bool is_string ATTRIBUTE_UNUSED
)
2440 static const char emptyBytes
[256] = { 0 };
2442 if (size
< NUM_SIZE_LOOKUP
)
2443 order
= size_lookup
[size
];
2447 while (size
> OBJECT_SIZE (order
))
2451 if (fwrite (x
, size
, 1, f
) != 1)
2452 fatal_error (input_location
, "can%'t write PCH file: %m");
2454 /* If SIZE is not the same as OBJECT_SIZE(order), then we need to pad the
2455 object out to OBJECT_SIZE(order). This happens for strings. */
2457 if (size
!= OBJECT_SIZE (order
))
2459 unsigned padding
= OBJECT_SIZE (order
) - size
;
2461 /* To speed small writes, we use a nulled-out array that's larger
2462 than most padding requests as the source for our null bytes. This
2463 permits us to do the padding with fwrite() rather than fseek(), and
2464 limits the chance the OS may try to flush any outstanding writes. */
2465 if (padding
<= sizeof (emptyBytes
))
2467 if (fwrite (emptyBytes
, 1, padding
, f
) != padding
)
2468 fatal_error (input_location
, "can%'t write PCH file");
2472 /* Larger than our buffer? Just default to fseek. */
2473 if (fseek (f
, padding
, SEEK_CUR
) != 0)
2474 fatal_error (input_location
, "can%'t write PCH file");
2478 d
->written
[order
]++;
2479 if (d
->written
[order
] == d
->d
.totals
[order
]
2480 && fseek (f
, ROUND_UP_VALUE (d
->d
.totals
[order
] * OBJECT_SIZE (order
),
2483 fatal_error (input_location
, "can%'t write PCH file: %m");
2487 ggc_pch_finish (struct ggc_pch_data
*d
, FILE *f
)
2489 if (fwrite (&d
->d
, sizeof (d
->d
), 1, f
) != 1)
2490 fatal_error (input_location
, "can%'t write PCH file: %m");
2494 /* Move the PCH PTE entries just added to the end of by_depth, to the
2498 move_ptes_to_front (int count_old_page_tables
, int count_new_page_tables
)
2502 /* First, we swap the new entries to the front of the varrays. */
2503 page_entry
**new_by_depth
;
2504 unsigned long **new_save_in_use
;
2506 new_by_depth
= XNEWVEC (page_entry
*, G
.by_depth_max
);
2507 new_save_in_use
= XNEWVEC (unsigned long *, G
.by_depth_max
);
2509 memcpy (&new_by_depth
[0],
2510 &G
.by_depth
[count_old_page_tables
],
2511 count_new_page_tables
* sizeof (void *));
2512 memcpy (&new_by_depth
[count_new_page_tables
],
2514 count_old_page_tables
* sizeof (void *));
2515 memcpy (&new_save_in_use
[0],
2516 &G
.save_in_use
[count_old_page_tables
],
2517 count_new_page_tables
* sizeof (void *));
2518 memcpy (&new_save_in_use
[count_new_page_tables
],
2520 count_old_page_tables
* sizeof (void *));
2523 free (G
.save_in_use
);
2525 G
.by_depth
= new_by_depth
;
2526 G
.save_in_use
= new_save_in_use
;
2528 /* Now update all the index_by_depth fields. */
2529 for (i
= G
.by_depth_in_use
; i
> 0; --i
)
2531 page_entry
*p
= G
.by_depth
[i
-1];
2532 p
->index_by_depth
= i
-1;
2535 /* And last, we update the depth pointers in G.depth. The first
2536 entry is already 0, and context 0 entries always start at index
2537 0, so there is nothing to update in the first slot. We need a
2538 second slot, only if we have old ptes, and if we do, they start
2539 at index count_new_page_tables. */
2540 if (count_old_page_tables
)
2541 push_depth (count_new_page_tables
);
2545 ggc_pch_read (FILE *f
, void *addr
)
2547 struct ggc_pch_ondisk d
;
2549 char *offs
= (char *) addr
;
2550 unsigned long count_old_page_tables
;
2551 unsigned long count_new_page_tables
;
2553 count_old_page_tables
= G
.by_depth_in_use
;
2555 /* We've just read in a PCH file. So, every object that used to be
2556 allocated is now free. */
2558 #ifdef ENABLE_GC_CHECKING
2561 /* Since we free all the allocated objects, the free list becomes
2562 useless. Validate it now, which will also clear it. */
2563 validate_free_objects ();
2565 /* No object read from a PCH file should ever be freed. So, set the
2566 context depth to 1, and set the depth of all the currently-allocated
2567 pages to be 1 too. PCH pages will have depth 0. */
2568 gcc_assert (!G
.context_depth
);
2569 G
.context_depth
= 1;
2570 for (i
= 0; i
< NUM_ORDERS
; i
++)
2573 for (p
= G
.pages
[i
]; p
!= NULL
; p
= p
->next
)
2574 p
->context_depth
= G
.context_depth
;
2577 /* Allocate the appropriate page-table entries for the pages read from
2579 if (fread (&d
, sizeof (d
), 1, f
) != 1)
2580 fatal_error (input_location
, "can%'t read PCH file: %m");
2582 for (i
= 0; i
< NUM_ORDERS
; i
++)
2584 struct page_entry
*entry
;
2590 if (d
.totals
[i
] == 0)
2593 bytes
= PAGE_ALIGN (d
.totals
[i
] * OBJECT_SIZE (i
));
2594 num_objs
= bytes
/ OBJECT_SIZE (i
);
2595 entry
= XCNEWVAR (struct page_entry
, (sizeof (struct page_entry
)
2597 + BITMAP_SIZE (num_objs
+ 1)));
2598 entry
->bytes
= bytes
;
2600 entry
->context_depth
= 0;
2602 entry
->num_free_objects
= 0;
2606 j
+ HOST_BITS_PER_LONG
<= num_objs
+ 1;
2607 j
+= HOST_BITS_PER_LONG
)
2608 entry
->in_use_p
[j
/ HOST_BITS_PER_LONG
] = -1;
2609 for (; j
< num_objs
+ 1; j
++)
2610 entry
->in_use_p
[j
/ HOST_BITS_PER_LONG
]
2611 |= 1L << (j
% HOST_BITS_PER_LONG
);
2613 for (pte
= entry
->page
;
2614 pte
< entry
->page
+ entry
->bytes
;
2616 set_page_table_entry (pte
, entry
);
2618 if (G
.page_tails
[i
] != NULL
)
2619 G
.page_tails
[i
]->next
= entry
;
2622 G
.page_tails
[i
] = entry
;
2624 /* We start off by just adding all the new information to the
2625 end of the varrays, later, we will move the new information
2626 to the front of the varrays, as the PCH page tables are at
2628 push_by_depth (entry
, 0);
2631 /* Now, we update the various data structures that speed page table
2633 count_new_page_tables
= G
.by_depth_in_use
- count_old_page_tables
;
2635 move_ptes_to_front (count_old_page_tables
, count_new_page_tables
);
2637 /* Update the statistics. */
2638 G
.allocated
= G
.allocated_last_gc
= offs
- (char *)addr
;