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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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
* of the License, 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.
*
* $URL$
* $Id$
*
*/
#include "sci/engine/gc.h"
#include "common/array.h"
namespace Sci {
//#define DEBUG_GC
//#define DEBUG_GC_VERBOSE
struct WorklistManager {
Common::Array<reg_t> _worklist;
reg_t_hash_map _map;
void push(reg_t reg) {
if (!reg.segment) // No numbers
return;
#ifdef DEBUG_GC_VERBOSE
sciprintf("[GC] Adding %04x:%04x\n", PRINT_REG(reg));
#endif
if (_map.contains(reg))
return; // already dealt with it
_map.setVal(reg, true);
_worklist.push_back(reg);
}
};
static reg_t_hash_map *normalise_hashmap_ptrs(SegManager *sm, reg_t_hash_map &nonnormal_map) {
reg_t_hash_map *normal_map = new reg_t_hash_map();
for (reg_t_hash_map::iterator i = nonnormal_map.begin(); i != nonnormal_map.end(); ++i) {
reg_t reg = i->_key;
MemObject *mobj = (reg.segment < sm->_heap.size()) ? sm->_heap[reg.segment] : NULL;
if (mobj) {
reg = mobj->findCanonicAddress(sm, reg);
normal_map->setVal(reg, true);
}
}
return normal_map;
}
void add_outgoing_refs(void *refcon, reg_t addr) {
WorklistManager *wm = (WorklistManager *)refcon;
wm->push(addr);
}
reg_t_hash_map *find_all_used_references(EngineState *s) {
SegManager *sm = s->seg_manager;
reg_t_hash_map *normal_map = NULL;
WorklistManager wm;
uint i;
// Initialise
// Init: Registers
wm.push(s->r_acc);
wm.push(s->r_prev);
// Init: Value Stack
// We do this one by hand since the stack doesn't know the current execution stack
{
ExecStack &xs = s->_executionStack.back();
reg_t *pos;
for (pos = s->stack_base; pos < xs.sp; pos++)
wm.push(*pos);
}
#ifdef DEBUG_GC_VERBOSE
sciprintf("[GC] -- Finished adding value stack");
#endif
// Init: Execution Stack
Common::List<ExecStack>::iterator iter;
for (iter = s->_executionStack.begin();
iter != s->_executionStack.end(); ++iter) {
ExecStack &es = *iter;
if (es.type != EXEC_STACK_TYPE_KERNEL) {
wm.push(es.objp);
wm.push(es.sendp);
if (es.type == EXEC_STACK_TYPE_VARSELECTOR)
wm.push(*(es.addr.varp));
}
}
#ifdef DEBUG_GC_VERBOSE
sciprintf("[GC] -- Finished adding execution stack");
#endif
// Init: Explicitly loaded scripts
for (i = 1; i < sm->_heap.size(); i++)
if (sm->_heap[i]
&& sm->_heap[i]->getType() == MEM_OBJ_SCRIPT) {
Script *script = (Script *)sm->_heap[i];
if (script->lockers) { // Explicitly loaded?
// Locals, if present
wm.push(make_reg(script->locals_segment, 0));
// All objects (may be classes, may be indirectly reachable)
for (uint obj_nr = 0; obj_nr < script->_objects.size(); obj_nr++) {
wm.push(script->_objects[obj_nr].pos);
}
}
}
#ifdef DEBUG_GC_VERBOSE
sciprintf("[GC] -- Finished explicitly loaded scripts, done with root set");
#endif
// Run Worklist Algorithm
while (!wm._worklist.empty()) {
reg_t reg = wm._worklist.back();
wm._worklist.pop_back();
if (reg.segment != s->stack_segment) { // No need to repeat this one
#ifdef DEBUG_GC_VERBOSE
sciprintf("[GC] Checking %04x:%04x\n", PRINT_REG(reg));
#endif
if (reg.segment < sm->_heap.size() && sm->_heap[reg.segment])
sm->_heap[reg.segment]->listAllOutgoingReferences(s, reg, &wm, add_outgoing_refs);
}
}
// Normalise
normal_map = normalise_hashmap_ptrs(sm, wm._map);
return normal_map;
}
struct deallocator_t {
SegManager *segmgr;
MemObject *mobj;
#ifdef DEBUG_GC
char *segnames[MEM_OBJ_MAX + 1];
int segcount[MEM_OBJ_MAX + 1];
#endif
reg_t_hash_map *use_map;
};
void free_unless_used(void *refcon, reg_t addr) {
deallocator_t *deallocator = (deallocator_t *)refcon;
reg_t_hash_map *use_map = deallocator->use_map;
if (!use_map->contains(addr)) {
// Not found -> we can free it
deallocator->mobj->freeAtAddress(deallocator->segmgr, addr);
#ifdef DEBUG_GC
sciprintf("[GC] Deallocating %04x:%04x\n", PRINT_REG(addr));
deallocator->segcount[deallocator->mobj->getType()]++;
#endif
}
}
void run_gc(EngineState *s) {
uint seg_nr;
deallocator_t deallocator;
SegManager *sm = s->seg_manager;
#ifdef DEBUG_GC
sciprintf("[GC] Running...\n");
memset(&(deallocator.segcount), 0, sizeof(int) * (MEM_OBJ_MAX + 1));
#endif
deallocator.segmgr = sm;
deallocator.use_map = find_all_used_references(s);
for (seg_nr = 1; seg_nr < sm->_heap.size(); seg_nr++) {
if (sm->_heap[seg_nr] != NULL) {
deallocator.mobj = sm->_heap[seg_nr];
#ifdef DEBUG_GC
deallocator.segnames[deallocator.mobj->getType()] = deallocator.mobj->type; // FIXME: add a segment "name"
#endif
deallocator.mobj->listAllDeallocatable(seg_nr, &deallocator, free_unless_used);
}
}
delete deallocator.use_map;
#ifdef DEBUG_GC
{
int i;
sciprintf("[GC] Summary:\n");
for (i = 0; i <= MEM_OBJ_MAX; i++)
if (deallocator.segcount[i])
sciprintf("\t%d\t* %s\n", deallocator.segcount[i], deallocator.segnames[i]);
}
#endif
}
} // End of namespace Sci
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