#include "gc.h" #ifdef LOG_GC #include "../utils/time.h" #endif u64 gc_depth = 1; vfn gc_roots[8]; u32 gc_rootSz; void gc_addFn(vfn f) { if (gc_rootSz>=8) err("Too many GC root functions"); gc_roots[gc_rootSz++] = f; } Value* gc_rootObjs[512]; u32 gc_rootObjSz; void gc_add(B x) { assert(isVal(x)); if (gc_rootObjSz>=512) err("Too many GC root objects"); gc_rootObjs[gc_rootObjSz++] = v(x); } B* gc_rootBRefs[64]; u32 gc_rootBRefsSz; void gc_add_ref(B* x) { if (gc_rootBRefsSz>=64) err("Too many GC root B refs"); gc_rootBRefs[gc_rootBRefsSz++] = x; } static void gc_freeFreed(Value* v) { if (v->type==t_freed) mm_free(v); } static void gc_resetTag(Value* x) { x->mmInfo&= 0x7F; } void gc_visitRoots() { for (u32 i = 0; i < gc_rootSz; i++) gc_roots[i](); for (u32 i = 0; i < gc_rootObjSz; i++) mm_visitP(gc_rootObjs[i]); for (u32 i = 0; i < gc_rootBRefsSz; i++) mm_visit(*gc_rootBRefs[i]); } static void gc_tryFree(Value* v) { u8 t = v->type; #if defined(DEBUG) && !defined(CATCH_ERRORS) if (t==t_freed) err("GC found t_freed\n"); #endif if (t!=t_empty && !(v->mmInfo&0x80)) { if (t==t_shape || t==t_temp || t==t_talloc) return; #ifdef DONT_FREE v->flags = t; #else #if CATCH_ERRORS if (t==t_freed) { mm_free(v); return; } #endif #endif #ifdef LOG_GC gc_freedBytes+= mm_size(v); gc_freedCount++; #endif v->type = t_freed; ptr_inc(v); // required as otherwise the object may free itself while not done reading its own fields TIi(t,freeO)(v); tptr_dec(v, mm_free); // Object may not be immediately freed if it's not a part of a cycle, but instead a descendant of one. // It will be freed when the cycle is freed, and the t_freed type ensures it doesn't double-free itself } } #ifdef LOG_GC u64 gc_visitBytes, gc_visitCount, gc_freedBytes, gc_freedCount, gc_unkRefsBytes, gc_unkRefsCount; #endif #if GC_VISIT_V2 i32 visit_mode; enum { GC_DEC_REFC, // decrement refcount GC_INC_REFC, // increment refcount GC_MARK, // if unmarked, mark & visit GC_LISTBAD, // }; void gc_onVisit(Value* x) { switch (visit_mode) { default: UD; case GC_DEC_REFC: x->refc--; return; case GC_INC_REFC: x->refc++; return; case GC_MARK: { if (x->mmInfo&0x80) return; x->mmInfo|= 0x80; #ifdef LOG_GC gc_visitBytes+= mm_size(x); gc_visitCount++; #endif TIv(x,visit)(x); return; } } } static void gcv2_visit(Value* x) { TIv(x,visit)(x); } #if HEAP_VERIFY void gcv2_runHeapverify(i32 mode) { visit_mode = mode==0? GC_DEC_REFC : GC_INC_REFC; mm_forHeap(gcv2_visit); gc_visitRoots(); } #endif static Value** gcv2_bufS; static Value** gcv2_bufC; static Value** gcv2_bufE; FORCE_INLINE void gcv2_storeRemainingEnd(Value* x) { *gcv2_bufC = x; gcv2_bufC++; #ifdef LOG_GC gc_unkRefsBytes+= mm_size(x); gc_unkRefsCount++; #endif } static NOINLINE void gcv2_storeRemainingR(Value* x) { ux i = gcv2_bufC - gcv2_bufS; ux n = (gcv2_bufE-gcv2_bufS)*2; gcv2_bufS = realloc(gcv2_bufS, n*sizeof(Value*)); gcv2_bufC = gcv2_bufS + i; gcv2_bufE = gcv2_bufS + n; gcv2_storeRemainingEnd(x); } static void gcv2_storeRemaining(Value* x) { gc_resetTag(x); if (x->refc == 0) return; if (gcv2_bufC == gcv2_bufE) return gcv2_storeRemainingR(x); gcv2_storeRemainingEnd(x); } static void gc_run(bool toplevel) { if (toplevel) { mm_forHeap(gc_resetTag); } else { visit_mode = GC_DEC_REFC; mm_forHeap(gcv2_visit); gcv2_bufS = gcv2_bufC = malloc(1<<20); gcv2_bufE = gcv2_bufS + ((1<<20) / sizeof(Value*)); mm_forHeap(gcv2_storeRemaining); // incl. unmark visit_mode = GC_INC_REFC; mm_forHeap(gcv2_visit); } visit_mode = GC_MARK; gc_visitRoots(); if (!toplevel) { Value** c = gcv2_bufS; while (c < gcv2_bufC) mm_visitP(*(c++)); free(gcv2_bufS); } mm_forHeap(gc_tryFree); mm_forHeap(gc_freeFreed); } #else static void gc_run(bool toplevel) { mm_forHeap(gc_resetTag); gc_visitRoots(); mm_forHeap(gc_tryFree); mm_forHeap(gc_freeFreed); } #endif u64 gc_lastAlloc; void gc_forceGC(bool toplevel) { #if ENABLE_GC #ifdef LOG_GC u64 start = nsTime(); gc_visitBytes = 0; gc_freedBytes = 0; gc_visitCount = 0; gc_freedCount = 0; gc_unkRefsBytes = 0; gc_unkRefsCount = 0; u64 startSize = mm_heapUsed(); #endif gc_run(toplevel); u64 endSize = mm_heapUsed(); #ifdef LOG_GC fprintf(stderr, "GC kept "N64d"B/"N64d" objs, freed "N64d"B, incl. directly "N64d"B/"N64d" objs", gc_visitBytes, gc_visitCount, startSize-endSize, gc_freedBytes, gc_freedCount); #if GC_VISIT_V2 fprintf(stderr, "; unknown refs: "N64d"B/"N64d" objs", gc_unkRefsBytes, gc_unkRefsCount); #endif fprintf(stderr, "; took %.3fms\n", (nsTime()-start)/1e6); #endif gc_lastAlloc = endSize; #endif } bool gc_maybeGC() { if (gc_depth) return false; u64 used = mm_heapUsed(); if (used > gc_lastAlloc*2) { gc_forceGC(false); return true; } return false; }