src/runtime/gencgc-internal.h

   1 /*
   2  * Generational Conservative Garbage Collector for SBCL x86
   3  *
   4  * inline functions that gc-common.c needs sight of
   5  */
   6
   7
   8 /*
   9  * This software is part of the SBCL system. See the README file for
  10  * more information.
  11  *
  12  * This software is derived from the CMU CL system, which was
  13  * written at Carnegie Mellon University and released into the
  14  * public domain. The software is in the public domain and is
  15  * provided with absolutely no warranty. See the COPYING and CREDITS
  16  * files for more information.
  17  */
  18
  19 #ifndef _GENCGC_INTERNAL_H_
  20 #define _GENCGC_INTERNAL_H_
  21
  22 #include "gencgc-alloc-region.h"
  23 #include "genesis/code.h"
  24
  25 /* Size of a page, in bytes. FIXME: needs to be conditionalized per
  26  * architecture, preferably by someone with a clue as to what page
  27  * sizes are on archs other than x86 and PPC - Patrik */
  28 #define PAGE_BYTES 4096
  29
  30
  31 void gc_free_heap(void);
  32 inline int find_page_index(void *);
  33 inline void *page_address(int);
  34 int gencgc_handle_wp_violation(void *);
  35 lispobj *search_dynamic_space(lispobj *);
  36 \f
  37 struct page {
  38
  39     unsigned
  40         /* This is set when the page is write-protected. This should
  41          * always reflect the actual write_protect status of a page.
  42          * (If the page is written into, we catch the exception, make
  43          * the page writable, and clear this flag.) */
  44         write_protected :1,
  45         /* This flag is set when the above write_protected flag is
  46          * cleared by the SIGBUS handler (or SIGSEGV handler, for some
  47          * OSes). This is useful for re-scavenging pages that are
  48          * written during a GC. */
  49         write_protected_cleared :1,
  50         /* the region the page is allocated to: 0 for a free page; 1
  51          * for boxed objects; 2 for unboxed objects. If the page is
  52          * free the following slots are invalid (well the bytes_used
  53          * must be 0). */
  54         allocated :3,
  55         /* If this page should not be moved during a GC then this flag
  56          * is set. It's only valid during a GC for allocated pages. */
  57         dont_move :1,
  58         /* If the page is part of a large object then this flag is
  59          * set. No other objects should be allocated to these pages.
  60          * This is only valid when the page is allocated. */
  61         large_object :1;
  62
  63     /* the generation that this page belongs to. This should be valid
  64      * for all pages that may have objects allocated, even current
  65      * allocation region pages - this allows the space of an object to
  66      * be easily determined. */
  67     int  gen;
  68
  69     /* the number of bytes of this page that are used. This may be less
  70      * than the actual bytes used for pages within the current
  71      * allocation regions. It should be 0 for all unallocated pages (not
  72      * hard to achieve). */
  73     int  bytes_used;
  74
  75     /* It is important to know the offset to the first object in the
  76      * page. Currently it's only important to know if an object starts
  77      * at the beginning of the page in which case the offset would be 0. */
  78     int  first_object_offset;
  79 };
  80
  81 /* values for the page.allocated field */
  82
  83 \f
  84 /* the number of pages needed for the dynamic space - rounding up */
  85 #define NUM_PAGES ((DYNAMIC_SPACE_SIZE+PAGE_BYTES-1)/PAGE_BYTES)
  86 extern struct page page_table[NUM_PAGES];
  87
  88 \f
  89
  90 void sniff_code_object(struct code *code, unsigned displacement);
  91 void gencgc_apply_code_fixups(struct code *old_code, struct code *new_code);
  92
  93 int  update_x86_dynamic_space_free_pointer(void);
  94 void  gc_alloc_update_page_tables(int unboxed,
  95                                   struct alloc_region *alloc_region);
  96 /*
  97  * predicates
  98  */
  99 static inline int
 100 space_matches_p(lispobj obj, int space)
 101 {
 102     int page_index=(void*)obj - (void *)DYNAMIC_SPACE_START;
 103     return ((page_index >= 0)
 104             && ((page_index =
 105                  ((unsigned int)page_index)/PAGE_BYTES) < NUM_PAGES)
 106             && (page_table[page_index].gen == space));
 107 }
 108
 109 static inline boolean
 110 from_space_p(lispobj obj)
 111 {
 112     return space_matches_p(obj,from_space);
 113 }
 114
 115 static inline boolean
 116 new_space_p(lispobj obj)
 117 {
 118     return space_matches_p(obj,new_space);
 119 }
 120
 121
 122
 123 #endif