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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
struct WorklistManager {
Common::Array<reg_t> _worklist;
reg_t_hash_map _map;
void push(reg_t reg) {
if (!reg.segment) // No numbers
return;
debugC(2, kDebugLevelGC, "[GC] Adding %04x:%04x", PRINT_REG(reg));
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 *segMan, 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;
SegmentObj *mobj = (reg.segment < segMan->_heap.size()) ? segMan->_heap[reg.segment] : NULL;
if (mobj) {
reg = mobj->findCanonicAddress(segMan, 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 *segMan = s->_segMan;
reg_t_hash_map *normal_map = NULL;
WorklistManager wm;
uint i;
assert(!s->_executionStack.empty());
// 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
Common::List<ExecStack>::iterator iter;
{
iter = s->_executionStack.reverse_begin();
// Skip fake kernel stack frame if it's on top
if (((*iter).type == EXEC_STACK_TYPE_KERNEL))
--iter;
assert((iter != s->_executionStack.end()) && ((*iter).type != EXEC_STACK_TYPE_KERNEL));
ExecStack &xs = *iter;
reg_t *pos;
for (pos = s->stack_base; pos < xs.sp; pos++)
wm.push(*pos);
}
debugC(2, kDebugLevelGC, "[GC] -- Finished adding value stack");
// Init: Execution Stack
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.getVarPointer(s->_segMan)));
}
}
debugC(2, kDebugLevelGC, "[GC] -- Finished adding execution stack");
// Init: Explicitly loaded scripts
for (i = 1; i < segMan->_heap.size(); i++)
if (segMan->_heap[i]
&& segMan->_heap[i]->getType() == SEG_TYPE_SCRIPT) {
Script *script = (Script *)segMan->_heap[i];
if (script->getLockers()) { // Explicitly loaded?
// Locals, if present
wm.push(make_reg(script->_localsSegment, 0));
// All objects (may be classes, may be indirectly reachable)
ObjMap::iterator it;
const ObjMap::iterator end = script->_objects.end();
for (it = script->_objects.begin(); it != end; ++it) {
wm.push(it->_value.getPos());
}
}
}
debugC(2, kDebugLevelGC, "[GC] -- Finished explicitly loaded scripts, done with root set");
// Run Worklist Algorithm
SegmentId stack_seg = segMan->findSegmentByType(SEG_TYPE_STACK);
while (!wm._worklist.empty()) {
reg_t reg = wm._worklist.back();
wm._worklist.pop_back();
if (reg.segment != stack_seg) { // No need to repeat this one
debugC(2, kDebugLevelGC, "[GC] Checking %04x:%04x", PRINT_REG(reg));
if (reg.segment < segMan->_heap.size() && segMan->_heap[reg.segment])
segMan->_heap[reg.segment]->listAllOutgoingReferences(reg, &wm, add_outgoing_refs);
}
}
// Normalise
normal_map = normalise_hashmap_ptrs(segMan, wm._map);
return normal_map;
}
struct deallocator_t {
SegManager *segMan;
SegmentObj *mobj;
#ifdef DEBUG_GC
char *segnames[SEG_TYPE_MAX + 1];
int segcount[SEG_TYPE_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->segMan, addr);
#ifdef DEBUG_GC
debugC(2, kDebugLevelGC, "[GC] Deallocating %04x:%04x", PRINT_REG(addr));
deallocator->segcount[deallocator->mobj->getType()]++;
#endif
}
}
void run_gc(EngineState *s) {
uint seg_nr;
deallocator_t deallocator;
SegManager *segMan = s->_segMan;
#ifdef DEBUG_GC
debugC(2, kDebugLevelGC, "[GC] Running...");
memset(&(deallocator.segcount), 0, sizeof(int) * (SEG_TYPE_MAX + 1));
#endif
deallocator.segMan = segMan;
deallocator.use_map = find_all_used_references(s);
for (seg_nr = 1; seg_nr < segMan->_heap.size(); seg_nr++) {
if (segMan->_heap[seg_nr] != NULL) {
deallocator.mobj = segMan->_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;
debugC(2, kDebugLevelGC, "[GC] Summary:");
for (i = 0; i <= SEG_TYPE_MAX; i++)
if (deallocator.segcount[i])
debugC(2, kDebugLevelGC, "\t%d\t* %s", deallocator.segcount[i], deallocator.segnames[i]);
}
#endif
}
} // End of namespace Sci
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