src/runtime/gencgc.h

   1 /*
   2  * Generational Conservative Garbage Collector for SBCL x86
   3  */
   4
   5 /*
   6  * This software is part of the SBCL system. See the README file for
   7  * more information.
   8  *
   9  * This software is derived from the CMU CL system, which was
  10  * written at Carnegie Mellon University and released into the
  11  * public domain. The software is in the public domain and is
  12  * provided with absolutely no warranty. See the COPYING and CREDITS
  13  * files for more information.
  14  */
  15
  16 #ifndef _GENCGC_H_
  17 #define _GENCGC_H_
  18
  19 #include "genesis/code.h"
  20
  21 void gc_free_heap(void);
  22 inline int find_page_index(void *);
  23 inline void *page_address(int);
  24 int gencgc_handle_wp_violation(void *);
  25 lispobj *search_dynamic_space(lispobj *);
  26 \f
  27 struct page {
  28
  29     unsigned
  30         /* This is set when the page is write-protected. This should
  31          * always reflect the actual write_protect status of a page.
  32          * (If the page is written into, we catch the exception, make
  33          * the page writable, and clear this flag.) */
  34         write_protected :1,
  35         /* This flag is set when the above write_protected flag is
  36          * cleared by the SIGBUS handler (or SIGSEGV handler, for some
  37          * OSes). This is useful for re-scavenging pages that are
  38          * written during a GC. */
  39         write_protected_cleared :1,
  40         /* the region the page is allocated to: 0 for a free page; 1
  41          * for boxed objects; 2 for unboxed objects. If the page is
  42          * free the following slots are invalid (well the bytes_used
  43          * must be 0). */
  44         allocated :2,
  45         /* If this page should not be moved during a GC then this flag
  46          * is set. It's only valid during a GC for allocated pages. */
  47         dont_move :1,
  48         /* If the page is part of a large object then this flag is
  49          * set. No other objects should be allocated to these pages.
  50          * This is only valid when the page is allocated. */
  51         large_object :1;
  52
  53     /* the generation that this page belongs to. This should be valid
  54      * for all pages that may have objects allocated, even current
  55      * allocation region pages - this allows the space of an object to
  56      * be easily determined. */
  57     int  gen;
  58
  59     /* the number of bytes of this page that are used. This may be less
  60      * than the actual bytes used for pages within the current
  61      * allocation regions. It should be 0 for all unallocated pages (not
  62      * hard to achieve). */
  63     int  bytes_used;
  64
  65     /* It is important to know the offset to the first object in the
  66      * page. Currently it's only important to know if an object starts
  67      * at the beginning of the page in which case the offset would be 0. */
  68     int  first_object_offset;
  69 };
  70
  71 /* values for the page.allocated field */
  72 #define FREE_PAGE 0
  73 #define BOXED_PAGE 1
  74 #define UNBOXED_PAGE 2
  75
  76 /* values for the *_alloc_* parameters */
  77 #define ALLOC_BOXED 0
  78 #define ALLOC_UNBOXED 1
  79 #define ALLOC_QUICK 1
  80
  81 \f
  82 /* the number of pages needed for the dynamic space - rounding up */
  83 #define NUM_PAGES ((DYNAMIC_SPACE_SIZE+4095)/4096)
  84 extern struct page page_table[NUM_PAGES];
  85 \f
  86 \f
  87 void  gencgc_pickup_dynamic(void);
  88
  89 void sniff_code_object(struct code *code, unsigned displacement);
  90
  91 int  update_x86_dynamic_space_free_pointer(void);
  92 void  gc_alloc_update_page_tables(int unboxed,
  93                                   struct alloc_region *alloc_region);
  94 void gc_alloc_update_all_page_tables(void);
  95 void gc_set_region_empty(struct alloc_region *region);
  96 #endif _GENCGC_H_