Initial commit

backends/plugins/elf/memory-manager.cpp

@@ -0,0 +1,177 @@
+/* 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "common/scummsys.h"
+
+#if defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER)
+
+#include "backends/plugins/elf/memory-manager.h"
+#include "common/debug.h"
+#include "common/util.h"
+#include <malloc.h>
+
+namespace Common {
+DECLARE_SINGLETON(ELFMemoryManager);
+}
+
+ELFMemoryManager::ELFMemoryManager() :
+	_heap(0), _heapSize(0), _heapAlign(0),
+	_trackAllocs(false), _measuredSize(0), _measuredAlign(0),
+	_bytesAllocated(0) {}
+
+ELFMemoryManager::~ELFMemoryManager() {
+	free(_heap);
+	_heap = 0;
+}
+
+void ELFMemoryManager::trackPlugin(bool value) {
+	assert(!_heap);
+
+	if (value == _trackAllocs)
+		return;
+
+	_trackAllocs = value;
+
+	if (_trackAllocs) {	// start measuring
+		// start tracking allocations
+		_measuredAlign = 0;
+
+	} else {	// we're done measuring
+		// get the total allocated size
+		uint32 measuredSize = _allocList.back().end() - _allocList.front().start;
+
+		_heapSize = MAX(_heapSize, measuredSize);
+		_heapAlign = MAX(_heapAlign, _measuredAlign);
+
+		_allocList.clear();
+		_bytesAllocated = 0;	// reset
+
+		debug(2, "measured a plugin of size %d. Max size %d. Max align %d", measuredSize, _heapSize, _heapAlign);
+	}
+}
+
+void ELFMemoryManager::trackAlloc(uint32 align, uint32 size) {
+	if (!_measuredAlign)
+		_measuredAlign = align;
+
+	// use the allocate function to simulate allocation
+	allocateOnHeap(align, size);
+}
+
+void ELFMemoryManager::allocateHeap() {
+	if (!_heapSize) {
+		warning("ELFMemoryManager: Unable to allocate the heap as its size could not be determined.");
+		return;
+	}
+
+	// The memory manager should only allocate once
+	assert (!_heap);
+
+	// clear the list
+	_allocList.clear();
+	_bytesAllocated = 0;
+
+	debug(2, "ELFMemoryManager: allocating %d bytes aligned at %d as the \
+			plugin heap", _heapSize, _heapAlign);
+
+	// prepare the heap
+	if (_heapAlign)
+		_heap = ::memalign(_heapAlign, _heapSize);
+	else
+		_heap = ::malloc(_heapSize);
+
+	assert(_heap);
+}
+
+void *ELFMemoryManager::pluginAllocate(uint32 size) {
+	if (_heap) {
+		return pluginAllocate(sizeof(void *), size);
+	}
+	return ::malloc(size);
+}
+
+void *ELFMemoryManager::pluginAllocate(uint32 align, uint32 size) {
+	if (_heap) {
+		return allocateOnHeap(align, size);
+	}
+	return ::memalign(align, size);
+}
+
+void ELFMemoryManager::pluginDeallocate(void *ptr) {
+	if (_heap) {
+		return deallocateFromHeap(ptr);
+	}
+	return ::free(ptr);
+}
+
+// Allocate space for the request in our heap
+void *ELFMemoryManager::allocateOnHeap(uint32 align, uint32 size) {
+	byte *lastAddress = (byte *)_heap;
+
+	// We can't allow allocations smaller than sizeof(Allocation). This could
+	// only be from non-plugin allocations and would cause infinite recursion
+	// when allocating our Allocation in the list.
+	if (size <= sizeof(Allocation))
+		return 0;
+
+	Common::List<Allocation>::iterator i;
+	for (i = _allocList.begin(); i != _allocList.end(); i++) {
+		if (i->start - lastAddress > (int)size)
+			break;
+		lastAddress = i->end();
+		// align to desired alignment
+		if (align) {
+			lastAddress = (byte *)( ((uint32)lastAddress + align - 1) & ~(align - 1) );
+		}
+	}
+
+	// Check if we exceeded our heap limit
+	// We skip this case if we're only tracking allocations
+	if (!_trackAllocs && ((uint32)lastAddress + size > (uint32)_heap + _heapSize)) {
+		debug(2, "failed to find space to allocate %d bytes", size);
+		return 0;
+	}
+
+	_allocList.insert(i, Allocation(lastAddress, size));
+	_bytesAllocated += size;
+
+	debug(7, "ELFMemoryManager: allocated %d bytes at %p. Total %d bytes",
+		size, lastAddress, _bytesAllocated);
+
+	return lastAddress;
+}
+
+void ELFMemoryManager::deallocateFromHeap(void *ptr) {
+	Common::List<Allocation>::iterator i;
+	for (i = _allocList.begin(); i != _allocList.end(); i++) {
+		if (i->start == ptr) {
+			_bytesAllocated -= (*i).size;
+
+			debug(7, "ELFMemoryManager: freed %d bytes at %p. Total %d bytes",
+				(*i).size, (*i).start, _bytesAllocated);
+
+			_allocList.erase(i);
+			break;
+		}
+	}
+}
+
+#endif /* defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER) */