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// Copyright 2017 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "dawn/native/CommandAllocator.h"
#include <algorithm>
#include <climits>
#include <cstdlib>
#include <utility>
#include "dawn/common/Assert.h"
#include "dawn/common/Math.h"
namespace dawn::native {
// TODO(cwallez@chromium.org): figure out a way to have more type safety for the iterator
CommandIterator::CommandIterator() {
Reset();
}
CommandIterator::~CommandIterator() {
DAWN_ASSERT(IsEmpty());
}
CommandIterator::CommandIterator(CommandIterator&& other) {
if (!other.IsEmpty()) {
mBlocks = std::move(other.mBlocks);
other.Reset();
}
Reset();
}
CommandIterator& CommandIterator::operator=(CommandIterator&& other) {
DAWN_ASSERT(IsEmpty());
if (!other.IsEmpty()) {
mBlocks = std::move(other.mBlocks);
other.Reset();
}
Reset();
return *this;
}
CommandIterator::CommandIterator(CommandAllocator allocator) : mBlocks(allocator.AcquireBlocks()) {
Reset();
}
void CommandIterator::AcquireCommandBlocks(std::vector<CommandAllocator> allocators) {
DAWN_ASSERT(IsEmpty());
mBlocks.clear();
for (CommandAllocator& allocator : allocators) {
CommandBlocks blocks = allocator.AcquireBlocks();
if (!blocks.empty()) {
mBlocks.reserve(mBlocks.size() + blocks.size());
for (BlockDef& block : blocks) {
mBlocks.push_back(std::move(block));
}
}
}
Reset();
}
bool CommandIterator::NextCommandIdInNewBlock(uint32_t* commandId) {
mCurrentBlock++;
if (mCurrentBlock >= mBlocks.size()) {
Reset();
*commandId = detail::kEndOfBlock;
return false;
}
mCurrentPtr = AlignPtr(mBlocks[mCurrentBlock].block.get(), alignof(uint32_t));
return NextCommandId(commandId);
}
void CommandIterator::Reset() {
mCurrentBlock = 0;
if (mBlocks.empty()) {
// This will case the first NextCommandId call to try to move to the next block and stop
// the iteration immediately, without special casing the initialization.
mCurrentPtr = reinterpret_cast<char*>(&mEndOfBlock);
} else {
mCurrentPtr = AlignPtr(mBlocks[0].block.get(), alignof(uint32_t));
}
}
void CommandIterator::MakeEmptyAsDataWasDestroyed() {
if (IsEmpty()) {
return;
}
mCurrentPtr = reinterpret_cast<char*>(&mEndOfBlock);
mBlocks.clear();
Reset();
DAWN_ASSERT(IsEmpty());
}
bool CommandIterator::IsEmpty() const {
return mBlocks.empty();
}
// Potential TODO(crbug.com/dawn/835):
// - Host the size and pointer to next block in the block itself to avoid having an allocation
// in the vector
// - Assume T's alignof is, say 64bits, static assert it, and make commandAlignment a constant
// in Allocate
// - Be able to optimize allocation to one block, for command buffers expected to live long to
// avoid cache misses
// - Better block allocation, maybe have Dawn API to say command buffer is going to have size
// close to another
CommandAllocator::CommandAllocator() {
ResetPointers();
}
CommandAllocator::~CommandAllocator() {
Reset();
}
CommandAllocator::CommandAllocator(CommandAllocator&& other)
: mBlocks(std::move(other.mBlocks)), mLastAllocationSize(other.mLastAllocationSize) {
other.mBlocks.clear();
if (!other.IsEmpty()) {
mCurrentPtr = other.mCurrentPtr;
mEndPtr = other.mEndPtr;
} else {
ResetPointers();
}
other.Reset();
}
CommandAllocator& CommandAllocator::operator=(CommandAllocator&& other) {
Reset();
if (!other.IsEmpty()) {
std::swap(mBlocks, other.mBlocks);
mLastAllocationSize = other.mLastAllocationSize;
mCurrentPtr = other.mCurrentPtr;
mEndPtr = other.mEndPtr;
}
other.Reset();
return *this;
}
void CommandAllocator::Reset() {
ResetPointers();
mBlocks.clear();
mLastAllocationSize = kDefaultBaseAllocationSize;
}
bool CommandAllocator::IsEmpty() const {
return mCurrentPtr == reinterpret_cast<const char*>(&mPlaceholderSpace[0]);
}
CommandBlocks&& CommandAllocator::AcquireBlocks() {
DAWN_ASSERT(mCurrentPtr != nullptr && mEndPtr != nullptr);
DAWN_ASSERT(IsPtrAligned(mCurrentPtr, alignof(uint32_t)));
DAWN_ASSERT(mCurrentPtr + sizeof(uint32_t) <= mEndPtr);
*reinterpret_cast<uint32_t*>(mCurrentPtr) = detail::kEndOfBlock;
mCurrentPtr = nullptr;
mEndPtr = nullptr;
return std::move(mBlocks);
}
char* CommandAllocator::AllocateInNewBlock(uint32_t commandId,
size_t commandSize,
size_t commandAlignment) {
// When there is not enough space, we signal the kEndOfBlock, so that the iterator knows
// to move to the next one. kEndOfBlock on the last block means the end of the commands.
uint32_t* idAlloc = reinterpret_cast<uint32_t*>(mCurrentPtr);
*idAlloc = detail::kEndOfBlock;
// We'll request a block that can contain at least the command ID, the command and an
// additional ID to contain the kEndOfBlock tag.
size_t requestedBlockSize = commandSize + kWorstCaseAdditionalSize;
// The computation of the request could overflow.
if (DAWN_UNLIKELY(requestedBlockSize <= commandSize)) {
return nullptr;
}
if (DAWN_UNLIKELY(!GetNewBlock(requestedBlockSize))) {
return nullptr;
}
return Allocate(commandId, commandSize, commandAlignment);
}
bool CommandAllocator::GetNewBlock(size_t minimumSize) {
// Allocate blocks doubling sizes each time, to a maximum of 16k (or at least minimumSize).
mLastAllocationSize = std::max(minimumSize, std::min(mLastAllocationSize * 2, size_t(16384)));
auto block = std::unique_ptr<char[]>(new (std::nothrow) char[mLastAllocationSize]);
if (DAWN_UNLIKELY(block == nullptr)) {
return false;
}
mCurrentPtr = AlignPtr(block.get(), alignof(uint32_t));
mEndPtr = block.get() + mLastAllocationSize;
mBlocks.push_back({mLastAllocationSize, std::move(block)});
return true;
}
void CommandAllocator::ResetPointers() {
mCurrentPtr = reinterpret_cast<char*>(&mPlaceholderSpace[0]);
mEndPtr = reinterpret_cast<char*>(&mPlaceholderSpace[1]);
}
} // namespace dawn::native