/* mm/cacao-gc/heap.c - GC module for heap management

   Copyright (C) 2006 R. Grafl, A. Krall, C. Kruegel,
   C. Oates, R. Obermaisser, M. Platter, M. Probst, S. Ring,
   E. Steiner, C. Thalinger, D. Thuernbeck, P. Tomsich, C. Ullrich,
   J. Wenninger, Institut f. Computersprachen - TU Wien

   This file is part of CACAO.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program 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.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.

   $Id$

*/


#include "config.h"
#include "vm/types.h"

#include "threads/lock-common.h"

#include "gc.h"
#include "final.h"
#include "heap.h"
#include "mark.h"
#include "region.h"
#include "mm/memory.h"
#include "native/include/java_lang_String.h"
#include "toolbox/logging.h"
#include "vm/global.h"
#include "vm/stringlocal.h"
#include "vm/vm.h"
#include "vmcore/rt-timing.h"


/* Global Variables ***********************************************************/

s4 heap_current_size;  /* current size of the heap */
s4 heap_maximal_size;  /* maximal size of the heap */
regioninfo_t *heap_region_sys;
regioninfo_t *heap_region_main;


void heap_init_objectheader(java_object_t *o, u4 bytelength)
{
	u4 wordcount;

	/* initialize the header flags */
	o->hdrflags = 0;

	/* align the size */
	/* TODO */

	/* calculate the wordcount as stored in the header */
    /* TODO: improve this to save wordcount and without header bytes */
    if ((bytelength & 0x03) == 0) {
        GC_ASSERT((bytelength & 0x03) == 0);
        wordcount = (bytelength >> 2);
        GC_ASSERT(wordcount != 0);
    } else {
        wordcount = GC_SIZE_DUMMY;
    }

	/* set the wordcount in the header */
    if (wordcount >= GC_SIZE_DUMMY) {
        GC_SET_SIZE(o, GC_SIZE_DUMMY);
    } else {
        GC_SET_SIZE(o, wordcount);
    }

}


void heap_update_references(rootset_t *rs, regioninfo_t *region, u4 offset)
{
	java_object_t  *o;
	java_object_t  *ref;
	java_object_t **refptr;
	u1* start;
	u1* end;
	int i;

	GC_LOG( dolog("GC: Updating all references (offset=%x) ...", offset); );

	start = region->base - offset;
	end = region->ptr - offset;
	GC_LOG( printf("Region previously was [ %p ; %p]\n", start, end); );

	GC_LOG2( printf("updating in root-sets ..."); );

	/* walk through all rootsets */
	while (rs) {

		/* walk through the references of this rootset */
		for (i = 0; i < rs->refcount; i++) {

			/* load the reference */
			refptr = rs->refs[i].ref;
			ref = *( refptr );

			GC_LOG2( printf("\troot pointer to %p\n", (void *) ref); );

			/* update the references */
			if (POINTS_INTO(ref, start, end))
				*refptr = ((u1 *) ref) + offset;

		}

		/* skip to next rootset in chain */
		rs = rs->next;

	}


	o = region->base;
	while (o < region->ptr) {

		GC_LOG2( printf("updating in %p ...\n", (void *) o); );

		if (IS_ARRAY(o)) {

			/* walk through the references of an Array */
			FOREACH_ARRAY_REF(o,ref,refptr,

				GC_LOG2( printf("\tarray-entry %p -> %p\n", (void *) ref, ((u1 *) ref) + offset); );

				if (POINTS_INTO(ref, start, end))
					*refptr = ((u1 *) ref) + offset;

			);

		} else {

			/* walk through the references of an Object */
			FOREACH_OBJECT_REF(o,ref,refptr,

				GC_LOG2( printf("\tobject-field %p -> %p\n", (void *) ref, ((u1 *) ref) + offset); );

				if (POINTS_INTO(ref, start, end))
					*refptr = ((u1 *) ref) + offset;

			);

		}

		/* skip to next object */
		o = ((u1 *) o) + get_object_size(o);

	}

}


void heap_increase_size(rootset_t *rs)
{
	s4 newsize;
	s4 resize_offset;

	/* only a quick sanity check */
	GC_ASSERT(heap_current_size <= heap_maximal_size);

	/* check if we are allowed to enlarge the heap */
	if (heap_current_size == heap_maximal_size)
		vm_abort("heap_increase_size: reached maximal heap size: out of memory");

	/* find out how much to increase the heap??? */
	newsize = 2 * heap_current_size; /* XXX TODO: better heuristic here */
	dolog("GC: Increasing Heap Size to %d bytes", newsize); /* XXX remove me */
	GC_LOG( dolog("GC: Increasing Heap Size to %d bytes", newsize); );

	/* resize the main heap region */
	resize_offset = region_resize(heap_region_main, newsize);

	/* update all references if necesarry */
	if (resize_offset != 0)
		heap_update_references(rs, heap_region_main, resize_offset);
	else
		dolog("GC WARNING: References are not updated after heap resizing!");

	/* set the new values */
	heap_current_size = newsize;

	GC_LOG( dolog("GC: Increasing Heap Size was successful");
			heap_println_usage(); );

	/* only a quick sanity check */
	GC_ASSERT(heap_current_size <= heap_maximal_size);

}


s4 heap_get_hashcode(java_object_t *o)
{
	s4 hashcode;

	if (!o)
		return 0;

	/* TODO: we need to lock the object here i think!!! */

	/* check if there is a hash attached to this object */
	if (GC_TEST_FLAGS(o, HDRFLAG_HASH_ATTACHED)) {

		hashcode = *( (s4 *) ( ((u1 *) o) + get_object_size(o) - SIZEOF_VOID_P ) ); /* TODO: clean this up!!! */
		GC_LOG2( dolog("GC: Hash re-taken: %d (0x%08x)", hashcode, hashcode); );

	} else {

		GC_SET_FLAGS(o, HDRFLAG_HASH_TAKEN);

		hashcode = (s4) (ptrint) o;
		GC_LOG2( dolog("GC: Hash taken: %d (0x%08x)", hashcode, hashcode); );

	}

	return hashcode;
}


static java_object_t *heap_alloc_intern(u4 bytelength, regioninfo_t *region, bool collect)
{
	java_object_t *p;

	/* only a quick sanity check */
	GC_ASSERT(region);
	GC_ASSERT(bytelength >= sizeof(java_object_t));

	/* align objects in memory */
	bytelength = GC_ALIGN(bytelength, GC_ALIGN_SIZE);

	/* lock the region */
	LOCK_MONITOR_ENTER(region);

#if 0
	/* heavy stress test */
	if (collect)
		gc_collect(0);
#endif

	/* check for sufficient free space */
	if (bytelength > region->free) {
		dolog("GC: Region out of memory! (collect=%d)", collect);

		if (collect) {
			gc_collect(0);
			GC_ASSERT(region->free >= bytelength);
		} else
			return NULL;
	}

	/* allocate the object in this region */
	p = (java_object_t *) region->ptr;
	region->ptr += bytelength;
	region->free -= bytelength;

	/* unlock the region */
	LOCK_MONITOR_EXIT(region);

	/* clear allocated memory region */
	GC_ASSERT(p);
	MSET(p, 0, u1, bytelength);

	/* set the header information */
	heap_init_objectheader(p, bytelength);

	return p;
}


/* heap_alloc ******************************************************************

   Allocates memory on the Java heap.

*******************************************************************************/

void *heap_alloc(u4 size, u4 references, methodinfo *finalizer, bool collect)
{
	java_object_t *p;
#if defined(ENABLE_RT_TIMING)
	struct timespec time_start, time_end;
#endif

	RT_TIMING_GET_TIME(time_start);

	p = heap_alloc_intern(size, heap_region_main, collect);

	if (p == NULL)
		return NULL;

#if defined(GCCONF_HDRFLAG_REFERENCING)
	/* We can't use a bool here for references, as it's passed as a
	   bitmask in builtin_new.  Thus we check for != 0. */
	if (references != 0) {
		GC_SET_FLAGS(p, HDRFLAG_REFERENCING);
	}
#endif

	/* register the finalizer for this object */
	if (finalizer != NULL) {
		final_register(p, finalizer);
	}

	RT_TIMING_GET_TIME(time_end);
	RT_TIMING_TIME_DIFF(time_start, time_end, RT_TIMING_GC_ALLOC);

	return p;
}


void *heap_alloc_uncollectable(u4 size)
{
	java_object_t *p;

	/* loader.c does this a lot for classes with fieldscount equal zero */
	if (size == 0)
		return NULL;

	p = heap_alloc_intern(size, heap_region_sys, false);

	if (p == NULL)
		return NULL;

	/* TODO: can this be overwritten by cloning??? */
	/* remember this object as uncollectable */
	GC_SET_FLAGS(p, HDRFLAG_UNCOLLECTABLE);

	return p;
}


void heap_free(void *p)
{
	GC_LOG( dolog("GC: Free %p", p); );
	GC_ASSERT(0);
}


/* Debugging ******************************************************************/

#if !defined(NDEBUG)
void heap_println_usage()
{
	printf("Current Heap Usage: Size=%d Free=%d\n",
			heap_current_size, heap_region_main->free);

	GC_ASSERT(heap_current_size == heap_region_main->size);
}
#endif


#if !defined(NDEBUG)
void heap_print_object_flags(java_object_t *o)
{
	printf("0x%02x [%s%s%s%s]",
		GC_GET_SIZE(o),
		GC_TEST_FLAGS(o, HDRFLAG_HASH_ATTACHED) ? "A" : " ",
		GC_TEST_FLAGS(o, HDRFLAG_HASH_TAKEN)    ? "T" : " ",
		GC_TEST_FLAGS(o, HDRFLAG_UNCOLLECTABLE) ? "U" : " ",
		GC_TEST_FLAGS(o, GC_FLAG_MARKED)        ? "M" : " ");
}
#endif


#if !defined(NDEBUG)
void heap_print_object(java_object_t *o)
{
	java_arrayheader  *a;
	classinfo         *c;

	/* check for null pointers */
	if (o == NULL) {
		printf("(NULL)");
		return;
	}

	/* print general information */
#if SIZEOF_VOID_P == 8
	printf("0x%016llx: ", (unsigned long long) o);
#else
	printf("0x%08lx: ", (unsigned long) o);
#endif

	/* check for invalid heap references */
	if (!POINTS_INTO(o, heap_region_main->base, heap_region_main->end) &&
		!POINTS_INTO(o, heap_region_sys->base, heap_region_sys->end))
	{
		printf("<<< No Heap Reference >>>");
		return;
	}

	/* print object flags */
	heap_print_object_flags(o);
	printf(" ");

	GC_ASSERT(o->vftbl);

	/* TODO */
	/* maybe this is not really an object */
	if (/*IS_CLASS*/ o->vftbl->class == class_java_lang_Class) {

		/* get the class information */
		c = (classinfo *) o;

		/* print the class information */
		printf("CLS ");
		class_print(c);

	} else if (/*IS_ARRAY*/ o->vftbl->arraydesc != NULL) {

		/* get the array information */
		a = (java_arrayheader *) o;
		c = o->vftbl->class;

		/* print the array information */
		printf("ARR ");
		/*class_print(c);*/
		utf_display_printable_ascii_classname(c->name);
		printf(" (size=%d)", a->size);

	} else /*IS_OBJECT*/ {

		/* get the object class */
		c = o->vftbl->class;

		/* print the object information */
		printf("OBJ ");
		/*class_print(c);*/
		utf_display_printable_ascii_classname(c->name);
		if (c == class_java_lang_String) {
			printf(" (string=\"");
			utf_display_printable_ascii(
					javastring_toutf((java_lang_String *) o, false));
			printf("\")");
		}

	}
}
#endif

#if !defined(NDEBUG)
void heap_dump_region(regioninfo_t *region, bool marked_only)
{
	java_object_t *o;
	u4             o_size;

	/* some basic sanity checks */
	GC_ASSERT(region->base <= region->ptr);

	printf("Heap-Dump:\n");

	/* walk the region in a linear style */
	o = (java_object_t *) region->base;
	while (o < region->ptr) {

		if (!marked_only || GC_IS_MARKED(o)) {
			printf("\t");
			heap_print_object(o);
			printf("\n");
		}

		/* get size of object */
		o_size = get_object_size(o);

		/* walk to next object */
		GC_ASSERT(o_size != 0);
		o = ((u1 *) o) + o_size;
	}

	printf("Heap-Dump finished.\n");
}
#endif


s4 get_object_size(java_object_t *o)
{
	java_arrayheader *a;
	classinfo        *c;
	s4                o_size;

	/* we can assume someone initialized the header */
	GC_ASSERT(o->hdrflags != 0);

	/* get the wordcount from the header */
	o_size = GC_GET_SIZE(o);

	/* maybe we need to calculate the size by hand */
	if (o_size != GC_SIZE_DUMMY) {
		GC_ASSERT(o_size != 0);
		o_size = o_size << 2;
	} else {

		/* TODO */
		/* maybe this is not really an object */
		if (/*IS_CLASS*/ o->vftbl->class == class_java_lang_Class) {
			/* we know the size of a classinfo */
			o_size = sizeof(classinfo);

		} else if (/*IS_ARRAY*/ o->vftbl->arraydesc != NULL) {
			/* compute size of this array */
			a = (java_arrayheader *) o;
			c = o->vftbl->class;
			o_size = c->vftbl->arraydesc->dataoffset +
					a->size * c->vftbl->arraydesc->componentsize;

		} else /*IS_OBJECT*/ {
			/* get the object size */
			c = o->vftbl->class;
			o_size = c->instancesize;
			GC_LOG( dolog("Got size (from Class): %d bytes", o_size); );
		}
	
	}

	/* align the size */
	o_size = GC_ALIGN(o_size, GC_ALIGN_SIZE);

	/* the hashcode attached to this object might increase the size */
	if (GC_TEST_FLAGS(o, HDRFLAG_HASH_ATTACHED))
		o_size += SIZEOF_VOID_P;

	return o_size;
}


/*
 * These are local overrides for various environment variables in Emacs.
 * Please do not remove this and leave it at the end of the file, where
 * Emacs will automagically detect them.
 * ---------------------------------------------------------------------
 * Local variables:
 * mode: c
 * indent-tabs-mode: t
 * c-basic-offset: 4
 * tab-width: 4
 * End:
 * vim:noexpandtab:sw=4:ts=4:
 */