clisp/gc.c
2024-09-01 17:17:08 +09:00

200 lines
2.9 KiB
C

#include "dat.h"
#include "fn.h"
#include <stdlib.h>
#include <setjmp.h>
#include <string.h>
#include <stdio.h>
enum
{
USING = 1 << 1,
OFFSET = sizeof(int),
};
GC gc = {0};
void
gcfree(void *src)
{
int *p = (int*)src - 1;
int sz = *p;
memset(p, 0, sz);
gc.using -= sz;
}
void
freeobj(Object *p)
{
gc.using -= sizeof(Object);
p->next = 0;
switch(p->type){
default:
break;
case OSTRING:
case OIDENT:
gcfree(p->beg);
break;
}
memset(p, 0, sizeof(Object));
if(gc.freed == 0)
gc.freed = p;
else{
p->next = gc.freed;
gc.freed = p;
}
}
void*
gcalloc(int sz)
{
sz += OFFSET;
if(sz % OFFSET) sz = sz + OFFSET - (sz % OFFSET);
for(u64 i = gc.sb; i < gc.se;){
u64 j = i;
for(;j - i < sz; j += OFFSET){
if(*(int*)(j) != 0)
break;
}
if(j - i == sz){
gc.using += sz;
*(int*)i = sz;
i += OFFSET;
return (void*)i;
}
i = j + *(int*)(j);
}
panic("gccalloc : Not impl yet raise");
}
void*
gcralloc(void *src, int sz)
{
void *dst = gcalloc(sz);
int osz = ((int*)src)[-1];
memcpy(dst, src, osz);
gcfree(src);
return dst;
}
void
mark(Object *obj)
{
if(obj == 0 || obj->flag&USING)
return;
obj->flag = USING;
switch(obj->type){
case OCELL:
mark(obj->car);
mark(obj->cdr);
break;
case OENV:
mark(obj->name);
mark(obj->vars);
mark(obj->up);
break;
case OFUNC:
mark(obj->params);
mark(obj->body);
mark(obj->env);
break;
}
}
void
gcsweep(void)
{
Object *last = 0;
for(Object *p = gc.objs; p;){
if(p->flag&USING){
p->flag = 0;
last = p;
p = p->next;
}else{
Object *tmp = p;
if(last == 0){
gc.objs = p->next;
}else{
last->next = p->next;
}
p = p->next;
freeobj(tmp);
}
}
}
int
isobj(u64 p)
{
if(gc.ob <= p && p < gc.oe){
p -= gc.ob;
return (p % sizeof(Object)) == 0;
}
return 0;
}
void
gcmark(void)
{
void *_ = 0;
u64 bot = (u64)&_;
for(; bot < gc.top; bot += sizeof(bot)){
u64 val = (u64)*(void**)bot;
if(isobj(val))
mark((Object*)val);
}
}
void
gcrun(void)
{
printf("before=> cap:%d using:%d remain:%d\n", gc.cap, gc.using, gc.cap-gc.using);
jmp_buf reg;
setjmp(reg);
gcmark();
gcsweep();
printf("after=> cap:%d using:%d remain:%d\n", gc.cap, gc.using, gc.cap-gc.using);
}
Object*
newobj(enum OType type)
{
if(gc.op + sizeof(Object) >= gc.oe){
panic("Not impl yet newobj raise");
}
gcrun();
gc.using += sizeof(Object);
Object *r = 0;
if(gc.freed){
r = gc.freed;
gc.freed = gc.freed->next;
}else{
r = (Object*)gc.op;
gc.op += sizeof(Object);
}
r->type = type;
if(gc.objs == 0)
gc.objs = r;
else{
r->next = gc.objs;
gc.objs = r;
}
return r;
}
void
gcinit(void *top, int cap)
{
gc.top = (u64)top;
if((gc.memory = malloc(cap)) == 0)
panic("can't alloc %d byte\n", cap);
gc.cap = cap;
gc.using = 0;
gc.op = gc.ob = (u64)gc.memory;
gc.oe = gc.op + (float)cap * 0.64;
gc.sb = (u64)gc.memory + (float)cap * 0.64;
gc.se = (u64)gc.memory + cap;
}