GC: completed defining gc functions

This commit is contained in:
Andrew Scott 2024-08-20 10:56:54 -04:00
parent 56311a928d
commit 9a54a80ccb
Signed by: a
GPG key ID: 7CD5A5977E4931C1
2 changed files with 48 additions and 1 deletions

45
gc.c Normal file
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@ -0,0 +1,45 @@
#include <stdlib.h>
#include "gc.h"
#include "vm.h"
void mark(struct garbageObject *obj) {
if (obj->mark) return;
++obj->mark;
if (obj->type == GARBAGE_PAIR) {
mark(obj->head);
mark(obj->tail);
}
}
void markAll(struct virtualMachine *vm) {
for (int i = 0; i < vm->stackSize; ++i) {
mark(vm->stack[i]);
}
}
void sweep(struct virtualMachine *vm) {
struct garbageObject **obj = &vm->head;
while (*obj) {
if (!(*obj)->mark) {
struct garbageObject *unreachable = *obj;
*obj = unreachable->next;
free(unreachable);
vm->refCount--;
} else {
(*obj)->mark = 0;
obj = &(*obj)->next;
}
}
}
int collect(struct virtualMachine *vm) {
int count = vm->refCount;
markAll(vm);
sweep(vm);
vm->refMax = vm->refCount * 2;
return count - vm->refCount;
}

4
gc.h
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@ -1,6 +1,8 @@
#ifndef GC_H
#define GC_H
#include "vm.h"
// Marks a single reference if it is still in use
void mark(struct garbageObject *obj);
@ -11,6 +13,6 @@ void markAll(struct virtualMachine *vm);
void sweep(struct virtualMachine *vm);
// Marks and Sweeps all references
void collect(struct virtualMachine *vm);
int collect(struct virtualMachine *vm);
#endif /* GC_H */