picrin/src/gc.c

837 lines
16 KiB
C

/**
* See Copyright Notice in picrin.h
*/
#include <stdlib.h>
#include "picrin.h"
#include "picrin/gc.h"
#include "picrin/pair.h"
#include "picrin/string.h"
#include "picrin/vector.h"
#include "picrin/irep.h"
#include "picrin/proc.h"
#include "picrin/port.h"
#include "picrin/blob.h"
#include "picrin/cont.h"
#include "picrin/error.h"
#include "picrin/macro.h"
#include "picrin/lib.h"
#include "picrin/var.h"
#include "picrin/data.h"
#include "picrin/dict.h"
#if GC_DEBUG
# include <string.h>
#endif
union header {
struct {
union header *ptr;
size_t size;
unsigned int mark : 1;
} s;
long alignment[4];
};
struct heap_page {
union header *basep, *endp;
struct heap_page *next;
};
struct pic_heap {
union header base, *freep;
struct heap_page *pages;
};
static void
heap_init(struct pic_heap *heap)
{
heap->base.s.ptr = &heap->base;
heap->base.s.size = 0; /* not 1, since it must never be used for allocation */
heap->base.s.mark = PIC_GC_UNMARK;
heap->freep = &heap->base;
heap->pages = NULL;
#if GC_DEBUG
printf("freep = %p\n", (void *)heap->freep);
#endif
}
struct pic_heap *
pic_heap_open()
{
struct pic_heap *heap;
heap = (struct pic_heap *)calloc(1, sizeof(struct pic_heap));
heap_init(heap);
return heap;
}
void
pic_heap_close(struct pic_heap *heap)
{
struct heap_page *page;
while (heap->pages) {
page = heap->pages;
heap->pages = heap->pages->next;
free(page);
}
}
static void gc_free(pic_state *, union header *);
static void
add_heap_page(pic_state *pic)
{
union header *up, *np;
struct heap_page *page;
size_t nu;
#if GC_DEBUG
puts("adding heap page!");
#endif
nu = (PIC_HEAP_PAGE_SIZE + sizeof(union header) - 1) / sizeof(union header) + 1;
up = (union header *)pic_calloc(pic, 1 + nu + 1, sizeof(union header));
up->s.size = nu + 1;
up->s.mark = PIC_GC_UNMARK;
gc_free(pic, up);
np = up + 1;
np->s.size = nu;
np->s.ptr = up->s.ptr;
up->s.size = 1;
up->s.ptr = np;
page = (struct heap_page *)pic_alloc(pic, sizeof(struct heap_page));
page->basep = up;
page->endp = up + nu + 1;
page->next = pic->heap->pages;
pic->heap->pages = page;
}
static void *
alloc(void *ptr, size_t size)
{
if (size == 0) {
if (ptr) {
free(ptr);
}
return NULL;
}
if (ptr) {
return realloc(ptr, size);
} else {
return malloc(size);
}
}
void *
pic_alloc(pic_state *pic, size_t size)
{
void *ptr;
ptr = alloc(NULL, size);
if (ptr == NULL && size > 0) {
pic_abort(pic, "memory exhausted");
}
return ptr;
}
void *
pic_realloc(pic_state *pic, void *ptr, size_t size)
{
ptr = alloc(ptr, size);
if (ptr == NULL && size > 0) {
pic_abort(pic, "memory exhausted");
}
return ptr;
}
void *
pic_calloc(pic_state *pic, size_t count, size_t size)
{
void *ptr;
size *= count;
ptr = alloc(NULL, size);
if (ptr == NULL && size > 0) {
pic_abort(pic, "memory exhausted");
}
memset(ptr, 0, size);
return ptr;
}
void
pic_free(pic_state *pic, void *ptr)
{
UNUSED(pic);
free(ptr);
}
static void
gc_protect(pic_state *pic, struct pic_object *obj)
{
if (pic->arena_idx >= pic->arena_size) {
pic->arena_size = pic->arena_size * 2 + 1;
pic->arena = pic_realloc(pic, pic->arena, sizeof(struct pic_object *) * pic->arena_size);
}
pic->arena[pic->arena_idx++] = obj;
}
pic_value
pic_gc_protect(pic_state *pic, pic_value v)
{
struct pic_object *obj;
if (pic_vtype(v) != PIC_VTYPE_HEAP) {
return v;
}
obj = pic_obj_ptr(v);
gc_protect(pic, obj);
return v;
}
size_t
pic_gc_arena_preserve(pic_state *pic)
{
return pic->arena_idx;
}
void
pic_gc_arena_restore(pic_state *pic, size_t state)
{
pic->arena_idx = state;
}
static void *
gc_alloc(pic_state *pic, size_t size)
{
union header *freep, *p, *prevp;
size_t nunits;
#if GC_DEBUG
assert(size > 0);
#endif
nunits = (size + sizeof(union header) - 1) / sizeof(union header) + 1;
prevp = freep = pic->heap->freep;
for (p = prevp->s.ptr; ; prevp = p, p = p->s.ptr) {
if (p->s.size >= nunits)
break;
if (p == freep) {
return NULL;
}
}
#if GC_DEBUG
{
unsigned char *c;
size_t s, i, j;
if (p->s.size == nunits) {
c = (unsigned char *)(p + p->s.size - nunits + 1);
s = nunits - 1;
} else {
c = (unsigned char *)(p + p->s.size - nunits);
s = nunits;
}
for (i = 0; i < s; ++i) {
for (j = 0; j < sizeof(union header); ++j) {
assert(c[i * sizeof(union header) + j] == 0xAA);
}
}
}
#endif
if (p->s.size == nunits) {
prevp->s.ptr = p->s.ptr;
}
else {
p->s.size -= nunits;
p += p->s.size;
p->s.size = nunits;
}
pic->heap->freep = prevp;
p->s.mark = PIC_GC_UNMARK;
#if GC_DEBUG
memset(p+1, 0, sizeof(union header) * (nunits - 1));
p->s.ptr = (union header *)0xcafebabe;
#endif
return (void *)(p + 1);
}
static void
gc_free(pic_state *pic, union header *bp)
{
union header *freep, *p;
#if GC_DEBUG
assert(bp != NULL);
assert(bp->s.size > 1);
#endif
#if GC_DEBUG
memset(bp + 1, 0xAA, (bp->s.size - 1) * sizeof(union header));
#endif
freep = pic->heap->freep;
for (p = freep; ! (bp > p && bp < p->s.ptr); p = p->s.ptr) {
if (p >= p->s.ptr && (bp > p || bp < p->s.ptr)) {
break;
}
}
if (bp + bp->s.size == p->s.ptr) {
bp->s.size += p->s.ptr->s.size;
bp->s.ptr = p->s.ptr->s.ptr;
#if GC_DEBUG
memset(p->s.ptr, 0xAA, sizeof(union header));
#endif
}
else {
bp->s.ptr = p->s.ptr;
}
if (p + p->s.size == bp && p->s.size > 1) {
p->s.size += bp->s.size;
p->s.ptr = bp->s.ptr;
#if GC_DEBUG
memset(bp, 0xAA, sizeof(union header));
#endif
}
else {
p->s.ptr = bp;
}
pic->heap->freep = p;
}
static void gc_mark(pic_state *, pic_value);
static void gc_mark_object(pic_state *pic, struct pic_object *obj);
static bool
gc_is_marked(union header *p)
{
return p->s.mark == PIC_GC_MARK;
}
static void
gc_unmark(union header *p)
{
p->s.mark = PIC_GC_UNMARK;
}
static void
gc_mark_object(pic_state *pic, struct pic_object *obj)
{
union header *p;
p = ((union header *)obj) - 1;
if (gc_is_marked(p))
return;
p->s.mark = PIC_GC_MARK;
switch (obj->tt) {
case PIC_TT_PAIR: {
gc_mark(pic, ((struct pic_pair *)obj)->car);
gc_mark(pic, ((struct pic_pair *)obj)->cdr);
break;
}
case PIC_TT_ENV: {
struct pic_env *env = (struct pic_env *)obj;
int i;
for (i = 0; i < env->regc; ++i) {
gc_mark(pic, env->regs[i]);
}
if (env->up) {
gc_mark_object(pic, (struct pic_object *)env->up);
}
break;
}
case PIC_TT_PROC: {
struct pic_proc *proc = (struct pic_proc *)obj;
if (proc->env) {
gc_mark_object(pic, (struct pic_object *)proc->env);
}
if (proc->attr) {
gc_mark_object(pic, (struct pic_object *)proc->attr);
}
if (pic_proc_irep_p(proc)) {
gc_mark_object(pic, (struct pic_object *)proc->u.irep);
}
break;
}
case PIC_TT_PORT: {
break;
}
case PIC_TT_ERROR: {
struct pic_error *err = (struct pic_error *)obj;
gc_mark_object(pic,(struct pic_object *)err->msg);
gc_mark(pic, err->irrs);
gc_mark_object(pic, (struct pic_object *)err->stack);
break;
}
case PIC_TT_STRING: {
break;
}
case PIC_TT_VECTOR: {
size_t i;
for (i = 0; i < ((struct pic_vector *)obj)->len; ++i) {
gc_mark(pic, ((struct pic_vector *)obj)->data[i]);
}
break;
}
case PIC_TT_BLOB: {
break;
}
case PIC_TT_CONT: {
struct pic_cont *cont = (struct pic_cont *)obj;
pic_value *stack;
pic_callinfo *ci;
size_t i;
/* block */
gc_mark_object(pic, (struct pic_object *)cont->blk);
/* stack */
for (stack = cont->st_ptr; stack != cont->st_ptr + cont->sp_offset; ++stack) {
gc_mark(pic, *stack);
}
/* callinfo */
for (ci = cont->ci_ptr + cont->ci_offset; ci != cont->ci_ptr; --ci) {
if (ci->env) {
gc_mark_object(pic, (struct pic_object *)ci->env);
}
}
/* arena */
for (i = 0; i < (size_t)cont->arena_idx; ++i) {
gc_mark_object(pic, cont->arena[i]);
}
/* error handlers */
for (i = 0; i < cont->try_jmp_idx; ++i) {
if (cont->try_jmps[i].handler) {
gc_mark_object(pic, (struct pic_object *)cont->try_jmps[i].handler);
}
}
/* result values */
gc_mark(pic, cont->results);
break;
}
case PIC_TT_MACRO: {
struct pic_macro *mac = (struct pic_macro *)obj;
if (mac->proc) {
gc_mark_object(pic, (struct pic_object *)mac->proc);
}
if (mac->senv) {
gc_mark_object(pic, (struct pic_object *)mac->senv);
}
break;
}
case PIC_TT_SENV: {
struct pic_senv *senv = (struct pic_senv *)obj;
if (senv->up) {
gc_mark_object(pic, (struct pic_object *)senv->up);
}
break;
}
case PIC_TT_LIB: {
struct pic_lib *lib = (struct pic_lib *)obj;
gc_mark(pic, lib->name);
gc_mark_object(pic, (struct pic_object *)lib->env);
break;
}
case PIC_TT_VAR: {
struct pic_var *var = (struct pic_var *)obj;
gc_mark(pic, var->stack);
if (var->conv) {
gc_mark_object(pic, (struct pic_object *)var->conv);
}
break;
}
case PIC_TT_IREP: {
struct pic_irep *irep = (struct pic_irep *)obj;
size_t i;
for (i = 0; i < irep->ilen; ++i) {
gc_mark_object(pic, (struct pic_object *)irep->irep[i]);
}
for (i = 0; i < irep->plen; ++i) {
gc_mark(pic, irep->pool[i]);
}
break;
}
case PIC_TT_DATA: {
struct pic_data *data = (struct pic_data *)obj;
xh_iter it;
xh_begin(&it, &data->storage);
while (xh_next(&it)) {
gc_mark(pic, xh_val(it.e, pic_value));
}
break;
}
case PIC_TT_DICT: {
struct pic_dict *dict = (struct pic_dict *)obj;
xh_iter it;
xh_begin(&it, &dict->hash);
while (xh_next(&it)) {
gc_mark(pic, xh_val(it.e, pic_value));
}
break;
}
case PIC_TT_BLK: {
struct pic_block *blk = (struct pic_block *)obj;
if (blk->prev) {
gc_mark_object(pic, (struct pic_object *)blk->prev);
}
if (blk->in) {
gc_mark_object(pic, (struct pic_object *)blk->in);
}
if (blk->out) {
gc_mark_object(pic, (struct pic_object *)blk->out);
}
break;
}
case PIC_TT_NIL:
case PIC_TT_BOOL:
case PIC_TT_FLOAT:
case PIC_TT_INT:
case PIC_TT_SYMBOL:
case PIC_TT_CHAR:
case PIC_TT_EOF:
case PIC_TT_UNDEF:
pic_abort(pic, "logic flaw");
}
}
static void
gc_mark(pic_state *pic, pic_value v)
{
struct pic_object *obj;
if (pic_vtype(v) != PIC_VTYPE_HEAP)
return;
obj = pic_obj_ptr(v);
gc_mark_object(pic, obj);
}
static void
gc_mark_phase(pic_state *pic)
{
pic_value *stack;
pic_callinfo *ci;
size_t i, j;
xh_iter it;
/* block */
if (pic->blk) {
gc_mark_object(pic, (struct pic_object *)pic->blk);
}
/* stack */
for (stack = pic->stbase; stack != pic->sp; ++stack) {
gc_mark(pic, *stack);
}
/* callinfo */
for (ci = pic->ci; ci != pic->cibase; --ci) {
if (ci->env) {
gc_mark_object(pic, (struct pic_object *)ci->env);
}
}
/* error object */
if (pic->err) {
gc_mark_object(pic, (struct pic_object *)pic->err);
}
/* arena */
for (j = 0; j < pic->arena_idx; ++j) {
gc_mark_object(pic, pic->arena[j]);
}
/* global variables */
for (i = 0; i < pic->glen; ++i) {
gc_mark(pic, pic->globals[i]);
}
/* macro objects */
xh_begin(&it, &pic->macros);
while (xh_next(&it)) {
gc_mark_object(pic, xh_val(it.e, struct pic_object *));
}
/* error handlers */
for (i = 0; i < pic->try_jmp_idx; ++i) {
if (pic->try_jmps[i].handler) {
gc_mark_object(pic, (struct pic_object *)pic->try_jmps[i].handler);
}
}
/* library table */
gc_mark(pic, pic->lib_tbl);
}
static void
gc_finalize_object(pic_state *pic, struct pic_object *obj)
{
#if GC_DEBUG
printf("* finalizing object: %s", pic_type_repr(pic_type(pic_obj_value(obj))));
// pic_debug(pic, pic_obj_value(obj));
puts("");
#endif
switch (obj->tt) {
case PIC_TT_PAIR: {
break;
}
case PIC_TT_ENV: {
break;
}
case PIC_TT_PROC: {
break;
}
case PIC_TT_VECTOR: {
pic_free(pic, ((struct pic_vector *)obj)->data);
break;
}
case PIC_TT_BLOB: {
pic_free(pic, ((struct pic_blob *)obj)->data);
break;
}
case PIC_TT_STRING: {
XROPE_DECREF(((struct pic_string *)obj)->rope);
break;
}
case PIC_TT_PORT: {
break;
}
case PIC_TT_ERROR: {
break;
}
case PIC_TT_CONT: {
struct pic_cont *cont = (struct pic_cont *)obj;
pic_free(pic, cont->stk_ptr);
pic_free(pic, cont->st_ptr);
pic_free(pic, cont->ci_ptr);
pic_free(pic, cont->arena);
pic_free(pic, cont->try_jmps);
break;
}
case PIC_TT_SENV: {
struct pic_senv *senv = (struct pic_senv *)obj;
xh_destroy(&senv->map);
break;
}
case PIC_TT_MACRO: {
break;
}
case PIC_TT_LIB: {
struct pic_lib *lib = (struct pic_lib *)obj;
xh_destroy(&lib->exports);
break;
}
case PIC_TT_VAR: {
break;
}
case PIC_TT_IREP: {
struct pic_irep *irep = (struct pic_irep *)obj;
pic_free(pic, irep->code);
pic_free(pic, irep->irep);
pic_free(pic, irep->pool);
break;
}
case PIC_TT_DATA: {
struct pic_data *data = (struct pic_data *)obj;
data->type->dtor(pic, data->data);
xh_destroy(&data->storage);
break;
}
case PIC_TT_DICT: {
struct pic_dict *dict = (struct pic_dict *)obj;
xh_destroy(&dict->hash);
break;
}
case PIC_TT_BLK: {
break;
}
case PIC_TT_NIL:
case PIC_TT_BOOL:
case PIC_TT_FLOAT:
case PIC_TT_INT:
case PIC_TT_SYMBOL:
case PIC_TT_CHAR:
case PIC_TT_EOF:
case PIC_TT_UNDEF:
pic_abort(pic, "logic flaw");
}
}
static void
gc_sweep_page(pic_state *pic, struct heap_page *page)
{
#if GC_DEBUG
static union header *NIL = (union header *)0xdeadbeef;
#else
static union header *NIL = NULL;
#endif
union header *bp, *p, *s = NIL, *t;
#if GC_DEBUG
int c = 0;
#endif
for (bp = page->basep; ; bp = bp->s.ptr) {
for (p = bp + bp->s.size; p != bp->s.ptr; p += p->s.size) {
if (p == page->endp) {
goto escape;
}
if (! gc_is_marked(p)) {
if (s == NIL) {
s = p;
}
else {
t->s.ptr = p;
}
t = p;
t->s.ptr = NIL; /* For dead objects we can safely reuse ptr field */
}
gc_unmark(p);
}
}
escape:
/* free! */
while (s != NIL) {
t = s->s.ptr;
gc_finalize_object(pic, (struct pic_object *)(s + 1));
gc_free(pic, s);
s = t;
#if GC_DEBUG
c++;
#endif
}
#if GC_DEBUG
printf("freed objects count: %d\n", c);
#endif
}
static void
gc_sweep_phase(pic_state *pic)
{
struct heap_page *page = pic->heap->pages;
while (page) {
gc_sweep_page(pic, page);
page = page->next;
}
}
void
pic_gc_run(pic_state *pic)
{
#if GC_DEBUG
struct heap_page *page;
#endif
#if DEBUG
puts("gc run!");
#endif
gc_mark_phase(pic);
gc_sweep_phase(pic);
#if GC_DEBUG
for (page = pic->heap->pages; page; page = page->next) {
union header *bp, *p;
unsigned char *c;
for (bp = page->basep; ; bp = bp->s.ptr) {
for (c = (unsigned char *)(bp+1); c != (unsigned char *)(bp + bp->s.size); ++c) {
assert(*c == 0xAA);
}
for (p = bp + bp->s.size; p != bp->s.ptr; p += p->s.size) {
if (p == page->endp) {
/* if (page->next) */
/* assert(bp->s.ptr == page->next->basep); */
/* else */
/* assert(bp->s.ptr == &pic->heap->base); */
goto escape;
}
assert(! gc_is_marked(p));
}
}
escape:
((void)0);
}
puts("not error on heap found! gc successfully finished");
#endif
}
struct pic_object *
pic_obj_alloc_unsafe(pic_state *pic, size_t size, enum pic_tt tt)
{
struct pic_object *obj;
#if GC_DEBUG
printf("*allocating: %s\n", pic_type_repr(tt));
#endif
#if GC_STRESS
pic_gc_run(pic);
#endif
obj = (struct pic_object *)gc_alloc(pic, size);
if (obj == NULL) {
pic_gc_run(pic);
obj = (struct pic_object *)gc_alloc(pic, size);
if (obj == NULL) {
add_heap_page(pic);
obj = (struct pic_object *)gc_alloc(pic, size);
if (obj == NULL)
pic_abort(pic, "GC memory exhausted");
}
}
obj->tt = tt;
return obj;
}
struct pic_object *
pic_obj_alloc(pic_state *pic, size_t size, enum pic_tt tt)
{
struct pic_object *obj;
obj = pic_obj_alloc_unsafe(pic, size, tt);
gc_protect(pic, obj);
return obj;
}