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 <limits.h>
  23 #include "gc.h"
  24 #include "gencgc-alloc-region.h"
  25 #include "genesis/code.h"
  26
  27 void gc_free_heap(void);
  28 inline page_index_t find_page_index(void *);
  29 inline void *page_address(page_index_t);
  30 int gencgc_handle_wp_violation(void *);
  31 \f
  32
  33 /* Note that this structure is also used from Lisp-side in
  34  * src/code/room.lisp, and the Lisp-side structure layout is currently
  35  * not groveled from C code but hardcoded. Any changes to the
  36  * structure layout need to be also made there.
  37  *
  38  * FIXME: We should probably just define this structure in Lisp, and
  39  * output the C version in genesis. -- JES, 2006-12-30.
  40  */
  41 struct page {
  42     /* The name of this field is not well-chosen for its actual use.
  43      * This is the offset from the start of the page to the start
  44      * of the alloc_region which contains/contained it.  It's negative or 0
  45      */
  46     long  first_object_offset;
  47
  48     /* the number of bytes of this page that are used. This may be less
  49      * than the actual bytes used for pages within the current
  50      * allocation regions. It should be 0 for all unallocated pages (not
  51      * hard to achieve).
  52      */
  53 #if PAGE_BYTES > USHRT_MAX
  54     unsigned int bytes_used;
  55 #else
  56     unsigned short bytes_used;
  57 #endif
  58
  59     unsigned
  60         /* This is set when the page is write-protected. This should
  61          * always reflect the actual write_protect status of a page.
  62          * (If the page is written into, we catch the exception, make
  63          * the page writable, and clear this flag.) */
  64         write_protected :1,
  65         /* This flag is set when the above write_protected flag is
  66          * cleared by the SIGBUS handler (or SIGSEGV handler, for some
  67          * OSes). This is useful for re-scavenging pages that are
  68          * written during a GC. */
  69         write_protected_cleared :1,
  70         /* the region the page is allocated to: 0 for a free page; 1
  71          * for boxed objects; 2 for unboxed objects. If the page is
  72          * free the following slots are invalid (well the bytes_used
  73          * must be 0). */
  74         allocated :3,
  75         /* If this page should not be moved during a GC then this flag
  76          * is set. It's only valid during a GC for allocated pages. */
  77         dont_move :1,
  78         /* If the page is part of a large object then this flag is
  79          * set. No other objects should be allocated to these pages.
  80          * This is only valid when the page is allocated. */
  81         large_object :1,
  82         /* True if the page is known to contain only zeroes. */
  83         need_to_zero :1;
  84
  85     /* the generation that this page belongs to. This should be valid
  86      * for all pages that may have objects allocated, even current
  87      * allocation region pages - this allows the space of an object to
  88      * be easily determined. */
  89     generation_index_t gen;
  90 };
  91
  92
  93 /* values for the page.allocated field */
  94
  95 \f
  96 extern page_index_t page_table_pages;
  97 extern struct page *page_table;
  98
  99 \f
 100 /* forward declarations */
 101
 102 void sniff_code_object(struct code *code, unsigned long displacement);
 103 void gencgc_apply_code_fixups(struct code *old_code, struct code *new_code);
 104
 105 long update_dynamic_space_free_pointer(void);
 106 void gc_alloc_update_page_tables(int unboxed,
 107                                  struct alloc_region *alloc_region);
 108 void gc_alloc_update_all_page_tables(void);
 109 void gc_set_region_empty(struct alloc_region *region);
 110
 111 /*
 112  * predicates
 113  */
 114 static inline boolean
 115 space_matches_p(lispobj obj, generation_index_t space)
 116 {
 117     page_index_t page_index=(void*)obj - (void *)DYNAMIC_SPACE_START;
 118     return ((page_index >= 0)
 119             && ((page_index =
 120                  ((unsigned long)page_index)/PAGE_BYTES) < page_table_pages)
 121             && (page_table[page_index].gen == space));
 122 }
 123
 124 static inline boolean
 125 from_space_p(lispobj obj)
 126 {
 127     return space_matches_p(obj,from_space);
 128 }
 129
 130 static inline boolean
 131 new_space_p(lispobj obj)
 132 {
 133     return space_matches_p(obj,new_space);
 134 }
 135
 136 extern page_index_t last_free_page;
 137 extern boolean gencgc_partial_pickup;
 138
 139 #endif