klisp

an open source interpreter for the Kernel Programming Language.
git clone http://git.hanabi.in/repos/klisp.git
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kgc.h (3467B)

      1 /*
      2 ** kgc.h
      3 ** Garbage Collector
      4 ** See Copyright Notice in klisp.h
      5 */
      6 
      7 /*
      8 ** SOURCE NOTE: This is almost textually from lua.
      9 ** Parts that don't apply, or don't apply yet to klisp are in comments.
     10 */
     11 
     12 #ifndef kgc_h
     13 #define kgc_h
     14 
     15 #include "kobject.h"
     16 #include "kstate.h"
     17 
     18 /*
     19 ** Possible states of the Garbage Collector
     20 */
     21 #define GCSpause	0
     22 #define GCSpropagate	1
     23 #define GCSsweepstring	2
     24 #define GCSsweep	3
     25 #define GCSfinalize	4
     26 
     27 /* NOTE: unlike in lua the gc flags have 16 bits in klisp,
     28    so resetbits is slightly different */
     29 
     30 /*
     31 ** some useful bit tricks
     32 */
     33 #define resetbits(x,m)	((x) &= cast(uint16_t, ~(m)))
     34 #define setbits(x,m)	((x) |= (m))
     35 #define testbits(x,m)	((x) & (m))
     36 #define bitmask(b)	(1<<(b))
     37 #define bit2mask(b1,b2)	(bitmask(b1) | bitmask(b2))
     38 #define k_setbit(x,b)	setbits(x, bitmask(b))
     39 #define resetbit(x,b)	resetbits(x, bitmask(b))
     40 #define testbit(x,b)	testbits(x, bitmask(b))
     41 #define set2bits(x,b1,b2)	setbits(x, (bit2mask(b1, b2)))
     42 #define reset2bits(x,b1,b2)	resetbits(x, (bit2mask(b1, b2)))
     43 #define test2bits(x,b1,b2)	testbits(x, (bit2mask(b1, b2)))
     44 
     45 /* NOTE: in klisp there is still no userdata, threads or finalization. 
     46    Also the field is called gct instead of marked */
     47 
     48 /*
     49 ** Layout for bit use in `gct' field:
     50 ** bit 0 - object is white (type 0)
     51 ** bit 1 - object is white (type 1)
     52 ** bit 2 - object is black
     53 ** bit 3 - for userdata: has been finalized
     54 ** bit 3 - for tables: has weak keys
     55 ** bit 4 - for tables: has weak values
     56 ** bit 5 - object is fixed (should not be collected)
     57 ** bit 6 - object is "super" fixed (only the main thread)
     58 */
     59 
     60 
     61 #define WHITE0BIT	0
     62 #define WHITE1BIT	1
     63 #define BLACKBIT	2
     64 #define FINALIZEDBIT	3
     65 #define KEYWEAKBIT	3
     66 #define VALUEWEAKBIT	4
     67 #define FIXEDBIT	5
     68 #define SFIXEDBIT	6
     69 #define WHITEBITS	bit2mask(WHITE0BIT, WHITE1BIT)
     70 
     71 
     72 #define iswhite(x)         test2bits((x)->gch.gct, WHITE0BIT, WHITE1BIT)
     73 #define isblack(x)         testbit((x)->gch.gct, BLACKBIT)
     74 #define isgray(x)	(!isblack(x) && !iswhite(x))
     75 
     76 #define otherwhite(g)	(g->currentwhite ^ WHITEBITS)
     77 #define isdead(g,v)	((v)->gch.gct & otherwhite(g) & WHITEBITS)
     78 
     79 #define changewhite(x)	((x)->gch.gct ^= WHITEBITS)
     80 #define gray2black(x)	k_setbit((x)->gch.gct, BLACKBIT)
     81 
     82 #define valiswhite(x)	(iscollectable(x) && iswhite(gcvalue(x)))
     83 
     84 #define klispC_white(g)	cast(uint16_t, (g)->currentwhite & WHITEBITS)
     85 
     86 
     87 #define klispC_checkGC(K) {                     \
     88         if (G(K)->totalbytes >= G(K)->GCthreshold)  \
     89             klispC_step(K); }
     90 
     91 
     92 #define klispC_barrier(K,p,v) { if (valiswhite(v) && isblack(obj2gco(p))) \
     93             klispC_barrierf(K,obj2gco(p),gcvalue(v)); }
     94 
     95 #define klispC_barriert(K,t,v) { if (valiswhite(v) && isblack(obj2gco(t))) \
     96             klispC_barrierback(K,t); }
     97 
     98 #define klispC_objbarrier(K,p,o)                        \
     99 	{ if (iswhite(obj2gco(o)) && isblack(obj2gco(p)))   \
    100             klispC_barrierf(K,obj2gco(p),obj2gco(o)); }
    101 
    102 #define klispC_objbarriert(K,t,o)                                       \
    103     { if (iswhite(obj2gco(o)) && isblack(obj2gco(t))) klispC_barrierback(K,t); }
    104 
    105 /* size_t klispC_separateudata (klisp_State *K, int all); */
    106 /* void klispC_callGCTM (klisp_State *K); */
    107 void klispC_freeall (klisp_State *K);
    108 void klispC_step (klisp_State *K);
    109 void klispC_fullgc (klisp_State *K);
    110 void klispC_link (klisp_State *K, GCObject *o, uint8_t tt, uint8_t flags);
    111 void klispC_barrierf (klisp_State *K, GCObject *o, GCObject *v);
    112 void klispC_barrierback (klisp_State *K, Table *t);
    113 
    114 #endif