From 7a1ea510a9fc43ccbc257601b149a90920332e13 Mon Sep 17 00:00:00 2001 From: Alex Auvolat Date: Fri, 15 Jul 2016 22:39:04 +0200 Subject: Add Lua source, not compiled yet as libc/libm functions remain unimplemented --- src/lib/lua/lgc.h | 147 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 147 insertions(+) create mode 100644 src/lib/lua/lgc.h (limited to 'src/lib/lua/lgc.h') diff --git a/src/lib/lua/lgc.h b/src/lib/lua/lgc.h new file mode 100644 index 0000000..aed3e18 --- /dev/null +++ b/src/lib/lua/lgc.h @@ -0,0 +1,147 @@ +/* +** $Id: lgc.h,v 2.91 2015/12/21 13:02:14 roberto Exp $ +** Garbage Collector +** See Copyright Notice in lua.h +*/ + +#ifndef lgc_h +#define lgc_h + + +#include "lobject.h" +#include "lstate.h" + +/* +** Collectable objects may have one of three colors: white, which +** means the object is not marked; gray, which means the +** object is marked, but its references may be not marked; and +** black, which means that the object and all its references are marked. +** The main invariant of the garbage collector, while marking objects, +** is that a black object can never point to a white one. Moreover, +** any gray object must be in a "gray list" (gray, grayagain, weak, +** allweak, ephemeron) so that it can be visited again before finishing +** the collection cycle. These lists have no meaning when the invariant +** is not being enforced (e.g., sweep phase). +*/ + + + +/* how much to allocate before next GC step */ +#if !defined(GCSTEPSIZE) +/* ~100 small strings */ +#define GCSTEPSIZE (cast_int(100 * sizeof(TString))) +#endif + + +/* +** Possible states of the Garbage Collector +*/ +#define GCSpropagate 0 +#define GCSatomic 1 +#define GCSswpallgc 2 +#define GCSswpfinobj 3 +#define GCSswptobefnz 4 +#define GCSswpend 5 +#define GCScallfin 6 +#define GCSpause 7 + + +#define issweepphase(g) \ + (GCSswpallgc <= (g)->gcstate && (g)->gcstate <= GCSswpend) + + +/* +** macro to tell when main invariant (white objects cannot point to black +** ones) must be kept. During a collection, the sweep +** phase may break the invariant, as objects turned white may point to +** still-black objects. The invariant is restored when sweep ends and +** all objects are white again. +*/ + +#define keepinvariant(g) ((g)->gcstate <= GCSatomic) + + +/* +** some useful bit tricks +*/ +#define resetbits(x,m) ((x) &= cast(lu_byte, ~(m))) +#define setbits(x,m) ((x) |= (m)) +#define testbits(x,m) ((x) & (m)) +#define bitmask(b) (1<<(b)) +#define bit2mask(b1,b2) (bitmask(b1) | bitmask(b2)) +#define l_setbit(x,b) setbits(x, bitmask(b)) +#define resetbit(x,b) resetbits(x, bitmask(b)) +#define testbit(x,b) testbits(x, bitmask(b)) + + +/* Layout for bit use in 'marked' field: */ +#define WHITE0BIT 0 /* object is white (type 0) */ +#define WHITE1BIT 1 /* object is white (type 1) */ +#define BLACKBIT 2 /* object is black */ +#define FINALIZEDBIT 3 /* object has been marked for finalization */ +/* bit 7 is currently used by tests (luaL_checkmemory) */ + +#define WHITEBITS bit2mask(WHITE0BIT, WHITE1BIT) + + +#define iswhite(x) testbits((x)->marked, WHITEBITS) +#define isblack(x) testbit((x)->marked, BLACKBIT) +#define isgray(x) /* neither white nor black */ \ + (!testbits((x)->marked, WHITEBITS | bitmask(BLACKBIT))) + +#define tofinalize(x) testbit((x)->marked, FINALIZEDBIT) + +#define otherwhite(g) ((g)->currentwhite ^ WHITEBITS) +#define isdeadm(ow,m) (!(((m) ^ WHITEBITS) & (ow))) +#define isdead(g,v) isdeadm(otherwhite(g), (v)->marked) + +#define changewhite(x) ((x)->marked ^= WHITEBITS) +#define gray2black(x) l_setbit((x)->marked, BLACKBIT) + +#define luaC_white(g) cast(lu_byte, (g)->currentwhite & WHITEBITS) + + +/* +** Does one step of collection when debt becomes positive. 'pre'/'pos' +** allows some adjustments to be done only when needed. macro +** 'condchangemem' is used only for heavy tests (forcing a full +** GC cycle on every opportunity) +*/ +#define luaC_condGC(L,pre,pos) \ + { if (G(L)->GCdebt > 0) { pre; luaC_step(L); pos;}; \ + condchangemem(L,pre,pos); } + +/* more often than not, 'pre'/'pos' are empty */ +#define luaC_checkGC(L) luaC_condGC(L,(void)0,(void)0) + + +#define luaC_barrier(L,p,v) ( \ + (iscollectable(v) && isblack(p) && iswhite(gcvalue(v))) ? \ + luaC_barrier_(L,obj2gco(p),gcvalue(v)) : cast_void(0)) + +#define luaC_barrierback(L,p,v) ( \ + (iscollectable(v) && isblack(p) && iswhite(gcvalue(v))) ? \ + luaC_barrierback_(L,p) : cast_void(0)) + +#define luaC_objbarrier(L,p,o) ( \ + (isblack(p) && iswhite(o)) ? \ + luaC_barrier_(L,obj2gco(p),obj2gco(o)) : cast_void(0)) + +#define luaC_upvalbarrier(L,uv) ( \ + (iscollectable((uv)->v) && !upisopen(uv)) ? \ + luaC_upvalbarrier_(L,uv) : cast_void(0)) + +LUAI_FUNC void luaC_fix (lua_State *L, GCObject *o); +LUAI_FUNC void luaC_freeallobjects (lua_State *L); +LUAI_FUNC void luaC_step (lua_State *L); +LUAI_FUNC void luaC_runtilstate (lua_State *L, int statesmask); +LUAI_FUNC void luaC_fullgc (lua_State *L, int isemergency); +LUAI_FUNC GCObject *luaC_newobj (lua_State *L, int tt, size_t sz); +LUAI_FUNC void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v); +LUAI_FUNC void luaC_barrierback_ (lua_State *L, Table *o); +LUAI_FUNC void luaC_upvalbarrier_ (lua_State *L, UpVal *uv); +LUAI_FUNC void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt); +LUAI_FUNC void luaC_upvdeccount (lua_State *L, UpVal *uv); + + +#endif -- cgit v1.2.3