initial GC commit
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2ef277d5bd
commit
dc2f25ef2a
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@ -1,10 +1,16 @@
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#ifndef GC_H__
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#define GC_H__
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enum pic_gc_mark {
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PIC_GC_MARK,
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PIC_GC_UNMARK
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};
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union header {
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struct {
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union header *ptr;
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size_t size;
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enum pic_gc_mark mark;
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} s;
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long alignment; /* force alignment for headers to be allocated at the size of long */
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};
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134
src/gc.c
134
src/gc.c
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@ -74,7 +74,7 @@ pic_gc_arena_restore(pic_state *pic, int state)
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}
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static void *
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pic_gc_alloc(pic_state *pic, size_t size)
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gc_alloc(pic_state *pic, size_t size)
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{
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union header *freep, *p, *prevp;
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size_t nunits;
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@ -100,34 +100,122 @@ pic_gc_alloc(pic_state *pic, size_t size)
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}
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pic->heap->freep = prevp;
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p->s.mark = PIC_GC_UNMARK;
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return (void *)(p + 1);
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}
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static void gc_mark(pic_state *, pic_value);
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static void
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pic_gc_free(pic_state *pic, void *ptr)
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gc_mark_object(pic_state *pic, struct pic_object *obj)
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{
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union header *bp, *p;
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union header *p;
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bp = (union header *)ptr - 1;
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p = (union header *)obj - 1;
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p->s.mark = PIC_GC_MARK;
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for (p = pic->heap->freep; !(p < bp && bp < p->s.ptr); p = p->s.ptr) {
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if (p >= p->s.ptr && (bp > p || bp < p->s.ptr))
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break;
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switch (obj->tt) {
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case PIC_TT_PAIR: {
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gc_mark(pic, ((struct pic_pair *)obj)->car);
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gc_mark(pic, ((struct pic_pair *)obj)->cdr);
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break;
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}
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if (bp + bp->s.size == p->s.ptr) {
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bp->s.size += p->s.ptr->s.size;
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bp->s.ptr = p->s.ptr->s.ptr;
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case PIC_TT_SYMBOL: {
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break;
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}
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else {
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bp->s.ptr = p->s.ptr;
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case PIC_TT_PROC: {
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break;
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}
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if (p + p->s.size == bp) {
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p->s.size += bp->s.size;
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p->s.ptr = bp->s.ptr;
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} else {
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p->s.ptr = bp;
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default:
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pic_raise(pic, "logic flaw");
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}
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pic->heap->freep = p;
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}
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static void
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gc_mark(pic_state *pic, pic_value v)
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{
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struct pic_object *obj;
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if (v.type != PIC_VTYPE_HEAP)
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return;
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obj = pic_object_ptr(v);
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gc_mark_object(pic, obj);
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}
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static void
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gc_mark_phase(pic_state *pic)
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{
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pic_value *stack;
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struct pic_env *env;
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int i;
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/* stack */
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for (stack = pic->stbase; stack != pic->sp; ++stack) {
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gc_mark(pic, *stack);
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}
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gc_mark(pic, *stack);
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/* arena */
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for (i = 0; i < pic->arena_idx; ++i) {
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gc_mark_object(pic, pic->arena[i]);
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}
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/* global env */
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env = pic->global_env;
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do {
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gc_mark(pic, env->assoc);
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} while ((env = env->parent) != NULL);
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}
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static bool
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is_marked(union header *p)
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{
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return p->s.mark == PIC_GC_MARK;
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}
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static void
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gc_unmark(union header *p)
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{
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p->s.mark = PIC_GC_UNMARK;
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}
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static void
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gc_sweep_phase(pic_state *pic)
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{
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union header *freep, *bp, *p;
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freep = pic->heap->freep;
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for (p = freep; p != freep; p = p->s.ptr) {
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for (bp = p + p->s.size; bp != p->s.ptr; bp += bp->s.size) {
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if (is_marked(bp)) {
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gc_unmark(bp);
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continue;
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}
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/* free! */
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if (bp + bp->s.size == p->s.ptr) {
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bp->s.size += p->s.ptr->s.size;
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bp->s.ptr = p->s.ptr->s.ptr;
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}
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else {
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bp->s.ptr = p->s.ptr;
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}
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if (p + p->s.size == bp) {
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p->s.size += bp->s.size;
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p->s.ptr = bp->s.ptr;
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}
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else {
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p->s.ptr = bp;
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}
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}
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}
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}
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static void
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pic_gc_run(pic_state *pic)
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{
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gc_mark_phase(pic);
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gc_sweep_phase(pic);
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}
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struct pic_object *
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@ -135,7 +223,15 @@ pic_obj_alloc(pic_state *pic, size_t size, enum pic_tt tt)
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{
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struct pic_object *obj;
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obj = (struct pic_object *)malloc(size);
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pic_gc_run(pic);
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obj = (struct pic_object *)gc_alloc(pic, size);
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if (obj == NULL) {
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puts("gc run!");
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pic_gc_run(pic);
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obj = (struct pic_object *)gc_alloc(pic, size);
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if (obj == NULL)
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pic_raise(pic, "memory exhausted");
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}
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obj->tt = tt;
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gc_protect(pic, obj);
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@ -25,6 +25,7 @@ pic_open()
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/* prepare VM stack */
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pic->stbase = pic->sp = (pic_value *)malloc(sizeof(pic_value) * 1024);
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pic->stend = pic->stbase + 1024;
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*pic->sp = pic_nil_value(); /* push dummy object */
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/* memory heap */
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pic->heap = (struct heap_page *)malloc(sizeof(struct heap_page));
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