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Implement garbage collection in runtime

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This commit is contained in:
Danila Fedorin 2020-02-06 11:32:19 -08:00
parent 30579afc6d
commit d86ff453bb
2 changed files with 59 additions and 7 deletions
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59
09/runtime.c
View File

@ -6,6 +6,8 @@
struct node_base* alloc_node() { struct node_base* alloc_node() {
struct node_base* new_node = malloc(sizeof(struct node_app)); struct node_base* new_node = malloc(sizeof(struct node_app));
new_node->gc_next = NULL;
new_node->gc_reachable = 0;
assert(new_node != NULL); assert(new_node != NULL);
return new_node; return new_node;
} }
@ -46,6 +48,27 @@ void free_node_direct(struct node_base* n) {
} }
} }
void gc_visit_node(struct node_base* n) {
if(n->gc_reachable) return;
n->gc_reachable = 1;
if(n->tag == NODE_APP) {
struct node_app* app = (struct node_app*) n;
gc_visit_node(app->left);
gc_visit_node(app->right);
} if(n->tag == NODE_IND) {
struct node_ind* ind = (struct node_ind*) n;
gc_visit_node(ind->next);
} if(n->tag == NODE_DATA) {
struct node_data* data = (struct node_data*) n;
struct node_base** to_visit = data->array;
while(*to_visit) {
gc_visit_node(*to_visit);
to_visit++;
}
}
}
void stack_init(struct stack* s) { void stack_init(struct stack* s) {
s->size = 4; s->size = 4;
s->count = 0; s->count = 0;
@ -82,12 +105,14 @@ void stack_popn(struct stack* s, size_t n) {
void gmachine_init(struct gmachine* g) { void gmachine_init(struct gmachine* g) {
stack_init(&g->stack); stack_init(&g->stack);
g->nodes = NULL; g->gc_nodes = NULL;
g->gc_node_count = 0;
g->gc_node_threshold = 128;
} }
void gmachine_free(struct gmachine* g) { void gmachine_free(struct gmachine* g) {
stack_free(&g->stack); stack_free(&g->stack);
struct node_base* to_free = g->nodes; struct node_base* to_free = g->gc_nodes;
struct node_base* next; struct node_base* next;
while(to_free) { while(to_free) {
@ -122,9 +147,10 @@ void gmachine_alloc(struct gmachine* g, size_t o) {
void gmachine_pack(struct gmachine* g, size_t n, int8_t t) { void gmachine_pack(struct gmachine* g, size_t n, int8_t t) {
assert(g->stack.count >= n); assert(g->stack.count >= n);
struct node_base** data = malloc(sizeof(*data) * n); struct node_base** data = malloc(sizeof(*data) * (n + 1));
assert(data != NULL); assert(data != NULL);
memcpy(data, &g->stack.data[g->stack.count - n], n * sizeof(*data)); memcpy(data, &g->stack.data[g->stack.count - n], n * sizeof(*data));
data[n] = NULL;
struct node_data* new_node = (struct node_data*) alloc_node(); struct node_data* new_node = (struct node_data*) alloc_node();
new_node->array = data; new_node->array = data;
@ -143,13 +169,36 @@ void gmachine_split(struct gmachine* g, size_t n) {
} }
struct node_base* gmachine_track(struct gmachine* g, struct node_base* b) { struct node_base* gmachine_track(struct gmachine* g, struct node_base* b) {
b->gc_next = g->nodes; g->gc_node_count++;
g->nodes = b; if(g->gc_node_count >= g->gc_node_threshold) {
gc_visit_node(b);
gmachine_gc(g);
g->gc_node_threshold *= 2;
}
b->gc_next = g->gc_nodes;
g->gc_nodes = b;
return b; return b;
} }
void gmachine_gc(struct gmachine* g) { void gmachine_gc(struct gmachine* g) {
for(size_t i = 0; i < g->stack.count; i++) {
gc_visit_node(g->stack.data[i]);
}
struct node_base** head_ptr = &g->gc_nodes;
while(*head_ptr) {
if((*head_ptr)->gc_reachable) {
(*head_ptr)->gc_reachable = 0;
head_ptr = &(*head_ptr)->gc_next;
} else {
struct node_base* to_free = *head_ptr;
*head_ptr = to_free->gc_next;
free_node_direct(to_free);
free(to_free);
g->gc_node_count--;
}
}
} }
void unwind(struct gmachine* g) { void unwind(struct gmachine* g) {

7
09/runtime.h
View File

@ -13,7 +13,7 @@ enum node_tag {
struct node_base { struct node_base {
enum node_tag tag; enum node_tag tag;
int8_t gc_color; int8_t gc_reachable;
struct node_base* gc_next; struct node_base* gc_next;
}; };
@ -51,6 +51,7 @@ struct node_num* alloc_num(int32_t n);
struct node_global* alloc_global(void (*f)(struct gmachine*), int32_t a); struct node_global* alloc_global(void (*f)(struct gmachine*), int32_t a);
struct node_ind* alloc_ind(struct node_base* n); struct node_ind* alloc_ind(struct node_base* n);
void free_node_direct(struct node_base*); void free_node_direct(struct node_base*);
void gc_visit_node(struct node_base*);
struct stack { struct stack {
size_t size; size_t size;
@ -67,7 +68,9 @@ void stack_popn(struct stack* s, size_t n);
struct gmachine { struct gmachine {
struct stack stack; struct stack stack;
struct node_base* nodes; struct node_base* gc_nodes;
int64_t gc_node_count;
int64_t gc_node_threshold;
}; };
void gmachine_init(struct gmachine* g); void gmachine_init(struct gmachine* g);