src/runtime/gencgc-alloc-region.h

   1 #ifndef _GENCGC_ALLOC_REGION_H_
   2 #define _GENCGC_ALLOC_REGION_H_
   3
   4 /* Abstract out the data for an allocation region allowing a single
   5  * routine to be used for allocation and closing. */
   6 /* Caution: if you change this, you may have to change compiler/generic/objdef
   7  * (for the THREAD object), all the backends' allocators, and room.lisp.
   8  * But as long as the first two words are left alone,
   9  * it's generally OK to add or remove other words.
  10  */
  11 struct alloc_region {
  12     /* These two are needed for quick allocation. */
  13     void  *free_pointer;
  14     void  *end_addr; /* pointer to the byte after the last usable byte */
  15     void  *start_addr;
  16 };
  17
  18 static inline void gc_set_region_empty(struct alloc_region *region)
  19 {
  20     /* Free-pointer has to be not equal to 0 because it's undefined behavior
  21      * to add any value whatsoever to the null pointer.
  22      * Annoying, isn't it.  http://c-faq.com/null/machexamp.html */
  23     region->free_pointer = region->end_addr = (void*)0x1000;
  24     /* Start 0 is the indicator of closed-ness. */
  25     region->start_addr = 0;
  26 }
  27
  28 static inline void gc_init_region(struct alloc_region *region)
  29 {
  30     // A distinction without a difference (it used to do one more assignment)
  31     gc_set_region_empty(region);
  32 }
  33
  34 typedef struct {
  35     struct alloc_region cons;
  36     struct alloc_region mixed;
  37     uword_t token;
  38 } arena_state;
  39
  40 // One region for each of page type.
  41 // These indices have no correlation to PAGE_TYPE constants.
  42 // MIXED has to always be at array index 0 because lisp accesses
  43 // it directly in #-sb-thread builds.
  44 extern struct alloc_region  gc_alloc_region[6];
  45 #define mixed_region   (&gc_alloc_region[0])
  46 #define small_mixed_region (&gc_alloc_region[1])
  47 #define unboxed_region (&gc_alloc_region[2])
  48 #define code_region    (&gc_alloc_region[3])
  49 #define boxed_region   (&gc_alloc_region[4])
  50 #define cons_region    (&gc_alloc_region[5])
  51 #define ASSERT_REGIONS_CLOSED() \
  52     gc_assert(!((uintptr_t)gc_alloc_region[0].start_addr \
  53                |(uintptr_t)gc_alloc_region[1].start_addr \
  54                |(uintptr_t)gc_alloc_region[2].start_addr \
  55                |(uintptr_t)gc_alloc_region[3].start_addr \
  56                |(uintptr_t)gc_alloc_region[4].start_addr \
  57                |(uintptr_t)gc_alloc_region[5].start_addr))
  58
  59 extern int gencgc_alloc_profiler;
  60 #if defined LISP_FEATURE_SB_THREAD || defined LISP_FEATURE_X86_64
  61 // x86-64 uses thread slots for the alloc regions even on threadless builds
  62 # define THREAD_ALLOC_REGION(threadvar,slot) &threadvar-> slot ##_tlab
  63 #else
  64 # define THREAD_ALLOC_REGION(threadvar,slot) main_thread_ ##slot ##_region
  65 #define main_thread_mixed_region (struct alloc_region*)(STATIC_SPACE_START + MIXED_REGION_OFFSET)
  66 #define main_thread_cons_region (struct alloc_region*)(STATIC_SPACE_START + CONS_REGION_OFFSET)
  67 #define main_thread_boxed_region (struct alloc_region*)(STATIC_SPACE_START + BOXED_REGION_OFFSET)
  68 #endif
  69
  70 #endif /*  _GENCGC_ALLOC_REGION_H_ */