+++ /dev/null
-/* This file is part of NIT ( http://www.nitlanguage.org ).
- *
- * Copyright 2009 Julien Chevalier <chevjulien@gmail.com>
- *
- * This file is free software, which comes along with NIT. This software is
- * distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
- * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
- * PARTICULAR PURPOSE. You can modify it is you want, provided this header
- * is kept unaltered, and a notification of the changes is added.
- * You are allowed to redistribute it and sell it, alone or is a part of
- * another product.
- */
-
-#include "gc.h"
-#ifdef DEBUG
-# include <assert.h>
-#else
-# define assert(x) while(0)
-#endif
-#include <unistd.h>
-#include "gc_static_objects_list.h"
-
-/** The current active heap.
- * During GC collect, it is the destination (i.e. the next active heap). */
-char *gc_heap_pointer;
-
-/** The inactive heap.
- * During GC collect, is is the source (i.e. the previous active heap). */
-char *gc_old_heap_pointer;
-
-/** The size (total capacity) of the active heap. */
-size_t gc_heap_size;
-
-/** The total size of currently allocated objects. */
-size_t gc_used_size;
-
-/** Typedef used by boxing val. FIXME: Do someting better! */
-typedef struct TBOX_struct {
- const classtable_elt_t *vft;
- char *val;
- bigint object_id;
-} *BOX_struct;
-
-/** First free position in the active heap. */
-char *gc_allocation_pointer;
-
-/** Position of objects copied but not yet visited (during GC collect). */
-char *gc_scavenging_pointer;
-
-/** List of global objects. */
-GC_List staticObjects;
-
-/** Size of a memory page. Used to grow or shrink the GC heap. */
-unsigned long page_size;
-
-/* Markbit manipulations */
-#define GET_MARKBIT(x) (((val_t)((x)[0].vft)) & 1)
-#define SET_MARKBIT(x) ((x)->vft = (void*)(((bigint)((x)->vft)) | 1))
-#define REMOVE_MARKBIT(x) ((x) ^ 1)
-
-void Nit_gc_init(void) {
- page_size = sysconf(_SC_PAGESIZE);
-
- gc_heap_pointer = calloc(1, page_size);
- if (gc_heap_pointer==NULL) exit(1);
- gc_heap_size = page_size;
- gc_used_size = 0;
-
- gc_allocation_pointer = gc_heap_pointer;
-
- gc_old_heap_pointer = NULL;
- gc_scavenging_pointer = NULL;
-
- GC_List_Init(&staticObjects);
-}
-
-/** Copy object to the new heap if needed then return the address of the copy. */
-static val_t GC_evacuation(obj_t object) {
- bigint size;
- bigint objectSize;
- val_t newAdress;
- Nit_NativeArray array;
-
- assert(ISOBJ(object) && !ISNULL(object));
- if (GET_MARKBIT(object) != (bigint)0) {
- /* Object already evacuated. So forward it. */
- newAdress = REMOVE_MARKBIT((bigint)((object)->vft));
- } else {
- newAdress = (val_t)gc_allocation_pointer;
- if (OBJ_IS_ARRAY(object)) {
- array = (Nit_NativeArray)object;
- size = sizeof(struct Nit_NativeArray) + ((array->size - 1) * sizeof(val_t));
- } else if (OBJ_IS_BOX(object)) {
- size = sizeof(struct TBOX_struct);
- } else {
- objectSize = (bigint)((object)[0].vft[1].i);
- size = (objectSize) * sizeof(val_t);
- }
- memcpy(gc_allocation_pointer, object, size);
- (object)[0].vft = (classtable_elt_t*)gc_allocation_pointer;
- SET_MARKBIT(object);
- gc_allocation_pointer += size;
- }
-
- return newAdress;
-}
-
-/** Process the next evacuated object to copy/update its fields. */
-static void GC_scavenging(void) {
- obj_t object;
- int size;
- int i;
- val_t referencedObject;
-
- object = (obj_t)gc_scavenging_pointer;
- if (OBJ_IS_BOX(object)) {
- size = sizeof(struct TBOX_struct);
- } else if (OBJ_IS_ARRAY(object)) {
- Nit_NativeArray array = (Nit_NativeArray)gc_scavenging_pointer;
- size = sizeof(struct Nit_NativeArray) + ((array->size - 1) * sizeof(val_t));
- for (i = 0; i < array->size; i++) {
- referencedObject = array->val[i];
- if (!ISNULL(referencedObject) && ISOBJ(referencedObject)) {
- array->val[i] = GC_evacuation((obj_t)referencedObject);
- }
- }
- } else {
- bigint objectSize = (bigint)((object)->vft[1].i);
- size = (objectSize) * sizeof(val_t);
- for (i = 2; i < objectSize; i++) {
- referencedObject = object[i].objectSize;
- if (!ISNULL(referencedObject) && ISOBJ(referencedObject)) {
- object[i].objectSize = GC_evacuation((obj_t)referencedObject);
- }
- }
- }
-
- gc_scavenging_pointer += size;
-}
-
-/** Collect live objects in the old head and copy them to the active heap. */
-static void GC_collect(void) {
- val_t *pointer;
- int i;
- int j;
- struct stack_frame_t *frame = stack_frame_head;
- GC_static_object *staticObject = staticObjects.top;
- val_t object;
- struct nitni_ref *global_ref;
- struct nitni_ref_array_link *local_ref_array_link; /* for native interface */
-
- gc_allocation_pointer = gc_heap_pointer;
- gc_scavenging_pointer = gc_heap_pointer;
-
- /* Process global objects (registered by GC_add_static_object) */
- for (i = 0; i < staticObjects.size; i++) {
- object = *(val_t*)(staticObject->pointer);
- if (!ISNULL(object) && ISOBJ(object)) {
- *(staticObject->pointer) = GC_evacuation((obj_t)object);
- }
- staticObject = staticObject->next;
- }
-
- /* Process global reference to Nit objects from C code */
- global_ref = nitni_global_ref_list->head;
- while (global_ref != NULL) {
- object = global_ref->val;
- if (!ISNULL(object) && ISOBJ(object)) {
- global_ref->val = GC_evacuation((obj_t)object);
- }
- global_ref = global_ref->next;
- }
-
- /* Process function frames (local variables) */
- while (frame != NULL) {
- for (j = 0; j < frame->REG_size; j++) {
- object = frame->REG[j];
- if (!ISNULL(object) && ISOBJ(object)) {
- frame->REG[j] = GC_evacuation((obj_t)object);
- }
- }
-
- /* Process C references to Nit objects */
- local_ref_array_link = frame->nitni_local_ref_head;
- while ( local_ref_array_link != NULL )
- {
- for (j = 0; j < local_ref_array_link->count; j++) {
- object = local_ref_array_link->reg[j]->val;
- if (!ISNULL(object) && ISOBJ(object)) {
- local_ref_array_link->reg[j]->val = GC_evacuation((obj_t)object);
- }
- }
- local_ref_array_link = local_ref_array_link->next;
- }
-
- if (frame == frame->prev) break;
- frame = frame->prev;
- }
- while (gc_allocation_pointer != gc_scavenging_pointer) {
- GC_scavenging();
- }
-
- gc_scavenging_pointer = NULL;
-
- gc_used_size = gc_allocation_pointer - gc_heap_pointer;
-}
-
-/** Allocate a new active heap. */
-static void GC_prepare_heap_size(size_t size) {
- assert(gc_old_heap_pointer == NULL);
- gc_old_heap_pointer = gc_heap_pointer;
-
- gc_heap_pointer = calloc(1, size);
- if (gc_heap_pointer == NULL) {
- exit(1);
- }
- gc_heap_size = size;
-}
-
-void Nit_gc_print_usage(void) {
-#if __STDC_VERSION >= 199901L
- /* If we are compiling with standard C99 or more recent, we can use %zu. */
- printf("GC: Size %zu usage %zu (%.2f%%)\n", gc_heap_size, gc_used_size, 100.0*gc_used_size/gc_heap_size);
-#else
- /* We are not compiling with a standard that allows us to use %zu, let's cast the two unsigned integers into the biggest we can !*/
- printf("GC: Size %lu usage %lu (%.2f%%)\n", (unsigned long)gc_heap_size, (unsigned long)gc_used_size, 100.0*gc_used_size/gc_heap_size);
-#endif
-}
-
-/** Enlarge the heap and collect dead objects. Can also shrink the heap.
- * Size is the aditionnal number of bytes required. */
-static void GC_enlarge_and_collect(size_t size) {
- size_t try_size;
-
- /* Heap grows exponentially. */
- try_size = gc_heap_size;
- while (size > (try_size - gc_used_size)) {
- try_size = try_size * 1.5;
- }
-
- /* Build a new heap. */
- GC_prepare_heap_size(try_size);
-
- /* Collect. */
- GC_collect();
-
- /* Free the old heap. */
- free(gc_old_heap_pointer);
- gc_old_heap_pointer = NULL;
-
- /* Shrink heap. */
- while (gc_heap_size > 2*page_size && 3*(gc_used_size+size) < gc_heap_size)
- gc_heap_size = gc_heap_size / 1.5;
- /*Nit_gc_print_usage();*/
-}
-
-void *Nit_gc_malloc(size_t size) {
- char *result;
-
- if (size > (gc_heap_size - gc_used_size))
- GC_enlarge_and_collect(size);
-
- result = gc_allocation_pointer;
- gc_allocation_pointer += size;
- gc_used_size += size;
-
- return result;
-}
-
-void GC_add_static_object(val_t *pointer) {
- GC_List_Push(&staticObjects, pointer);
-}
-
-/* Is invoked by intern method Sys:force_garbage_collection */
-void Nit_gc_force_garbage_collection( void ) {
- GC_enlarge_and_collect( 0 );
-}
nitlanguage / nit.git / blobdiff