STT-tensorflow/tensorflow/lite/experimental/writer/writer_lib.cc
A. Unique TensorFlower 91cb053af0 This CL optimizes C++11 range-based for loops where the variable is copied in each iteration but it would suffice to obtain it by const reference. This is only applied to loop variables of types that are expensive to copy which means they are not trivially copyable or have a non-trivial copy constructor or destructor.
To ensure that it is safe to replace the copy with a const reference the following heuristic is employed:
  The loop variable is const qualified.
  The loop variable is not const, but only const methods or operators are invoked on it, or it is used as const reference or value argument in constructors or function calls.

PiperOrigin-RevId: 305342272
Change-Id: I3e9955bf448d9670e41934437a90fa5c3b8c5b1c
2020-04-07 14:38:02 -07:00

372 lines
15 KiB
C++

/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/
#include "tensorflow/lite/experimental/writer/writer_lib.h"
#include <cstdlib>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include "tensorflow/lite/builtin_op_data.h"
#include "tensorflow/lite/c/common.h"
#include "tensorflow/lite/context_util.h"
#include "tensorflow/lite/core/subgraph.h"
#include "tensorflow/lite/experimental/writer/enum_mapping.h"
#include "tensorflow/lite/schema/reflection/schema_generated.h"
#include "tensorflow/lite/version.h"
namespace tflite {
std::pair<BuiltinOptions, flatbuffers::Offset<void>> CreateBuiltinUnion(
flatbuffers::FlatBufferBuilder* fbb, enum BuiltinOperator op,
void* builtin_op_data) {
switch (op) {
#include "tensorflow/lite/experimental/writer/option_writer_generated.h"
}
return std::make_pair(BuiltinOptions_NONE, flatbuffers::Offset<void>());
}
template <class T_OUTPUT, class T_INPUT>
flatbuffers::Offset<flatbuffers::Vector<T_OUTPUT>> SubgraphWriter::ExportVector(
flatbuffers::FlatBufferBuilder* fbb, const T_INPUT& v) {
std::vector<T_OUTPUT> inputs(v.begin(), v.end());
return fbb->template CreateVector<T_OUTPUT>(inputs);
}
flatbuffers::Offset<flatbuffers::Vector<flatbuffers::Offset<Operator>>>
SubgraphWriter::ExportOperators(flatbuffers::FlatBufferBuilder* fbb) {
std::vector<flatbuffers::Offset<Operator>> operators;
std::vector<int> operator_to_opcode;
// TODO(aselle): Augment this once we put execution plan in schema.
operator_to_opcode.resize(subgraph_->nodes_size(), -1);
for (int op_index : execution_plan_) {
const auto* node_and_registration =
subgraph_->node_and_registration(op_index);
const TfLiteRegistration* registration = &node_and_registration->second;
if (!registration->custom_name) {
operator_to_opcode[op_index] =
GetOpCodeForBuiltin(registration->builtin_code);
} else {
operator_to_opcode[op_index] =
GetOpCodeForCustom(registration->custom_name);
}
}
// second pass serialize operators
for (int op_index : execution_plan_) {
const auto* node_and_registration =
subgraph_->node_and_registration(op_index);
const TfLiteNode& node = node_and_registration->first;
const TfLiteRegistration& registration = node_and_registration->second;
flatbuffers::Offset<void> builtin_options;
BuiltinOptions builtin_options_type = BuiltinOptions_NONE;
// Custom data
// TODO(aselle): Custom options format is not known by default. Just assume
// for now.
auto custom_options_format = CustomOptionsFormat_FLEXBUFFERS;
flatbuffers::Offset<flatbuffers::Vector<uint8_t>> custom_options = 0;
if (!registration.custom_name) {
// builtin
auto builtin_options_and_type = CreateBuiltinUnion(
fbb, static_cast<enum BuiltinOperator>(registration.builtin_code),
node.builtin_data);
builtin_options = builtin_options_and_type.second;
builtin_options_type = builtin_options_and_type.first;
} else {
auto custom_writer = custom_op_to_writer_.find(registration.custom_name);
if (custom_writer != custom_op_to_writer_.end() &&
custom_writer->second) {
// delegate to custom writer if it exists
custom_writer->second(fbb, subgraph_, op_index, &custom_options,
&custom_options_format);
} else {
// use the custom data as fact
custom_options = fbb->CreateVector(
reinterpret_cast<const uint8_t*>(node.custom_initial_data),
node.custom_initial_data_size);
}
}
int opcode_index = operator_to_opcode[op_index];
std::vector<int> written_inputs =
RemapTensorIndicesToWritten(TfLiteIntArrayView(node.inputs));
std::vector<int> written_outputs =
RemapTensorIndicesToWritten(TfLiteIntArrayView(node.outputs));
auto inputs = ExportVector<int32_t>(fbb, written_inputs);
auto outputs = ExportVector<int32_t>(fbb, written_outputs);
operators.push_back(CreateOperator(*fbb, opcode_index, inputs, outputs,
builtin_options_type, builtin_options,
custom_options, custom_options_format));
}
return fbb->template CreateVector<flatbuffers::Offset<Operator>>(operators);
}
flatbuffers::Offset<flatbuffers::Vector<flatbuffers::Offset<Tensor>>>
SubgraphWriter::ExportTensors(flatbuffers::FlatBufferBuilder* fbb) {
// Initialized to -1.
// A value of -1 means this tensor will not be exported.
tensor_to_written_tensor_.resize(subgraph_->tensors_size(), -1);
std::vector<flatbuffers::Offset<Tensor>> tensors;
// Make a map from tensor index to whether the tensor is a temporary.
std::vector<bool> tensor_is_temporary(subgraph_->tensors_size(), false);
for (int op_index = 0; op_index < subgraph_->nodes_size(); ++op_index) {
const auto* node_and_registration =
subgraph_->node_and_registration(op_index);
for (auto tensor_index :
TfLiteIntArrayView(node_and_registration->first.temporaries))
tensor_is_temporary[tensor_index] = true;
}
// Now we need to remap all used tensor indices
int curr_output_index = 0;
for (int tensor_index = 0; tensor_index < subgraph_->tensors_size();
tensor_index++) {
// Temporary tensors and unused tensors will not be written.
if (!tensor_is_temporary[tensor_index] &&
unused_tensors_.find(tensor_index) == unused_tensors_.end()) {
tensor_to_written_tensor_[tensor_index] = curr_output_index++;
}
}
for (int tensor_index = 0; tensor_index < subgraph_->tensors_size();
++tensor_index) {
// Tensor not exported.
if (tensor_to_written_tensor_[tensor_index] == -1) continue;
if (TfLiteTensor* tensor = subgraph_->tensor(tensor_index)) {
// We only need to convert non temporaries
if (tensor->allocation_type != kTfLiteArenaRw &&
tensor->allocation_type != kTfLiteMmapRo &&
tensor->allocation_type != kTfLiteArenaRwPersistent)
continue;
// Allocate a buffer index
int buffer_index = 0; // This is null
if (tensor->allocation_type == kTfLiteMmapRo) {
buffer_index = buffers_.size();
buffers_.push_back(std::make_pair(
reinterpret_cast<const uint8_t*>(tensor->data.raw), tensor->bytes));
}
// Primitive type.
TensorType type = TfLiteTypeToSchemaType(tensor->type);
// Handle quantization
flatbuffers::Offset<QuantizationParameters> quantization_params;
const flatbuffers::Offset<flatbuffers::Vector<float>> null_array;
flatbuffers::Offset<flatbuffers::Vector<float>> scale_array;
flatbuffers::Offset<flatbuffers::Vector<int64_t>> zero_point_array;
if (tensor->quantization.type == kTfLiteAffineQuantization) {
if (tensor->params.scale != 0.f) {
// Quantization with a single argument array.
scale_array = fbb->CreateVector<float>({tensor->params.scale});
zero_point_array =
fbb->CreateVector<int64_t>({tensor->params.zero_point});
quantization_params = CreateQuantizationParameters(
*fbb, null_array, null_array, scale_array, zero_point_array);
} else { // Multi channel quantization.
const TfLiteAffineQuantization* params =
reinterpret_cast<TfLiteAffineQuantization*>(
tensor->quantization.params);
const size_t num_scales = params->scale->size;
std::vector<float> scale_vector(params->scale->data,
params->scale->data + num_scales);
std::vector<int64_t> zero_point_vector(
params->zero_point->data, params->zero_point->data + num_scales);
scale_array = fbb->CreateVector<float>(scale_vector);
zero_point_array = fbb->CreateVector<int64_t>(zero_point_vector);
quantization_params = CreateQuantizationParameters(
*fbb, null_array, null_array, scale_array, zero_point_array,
QuantizationDetails_NONE, 0, params->quantized_dimension);
}
}
// Shape
TfLiteIntArrayView shape_view(tensor->dims);
std::vector<int> shape =
std::vector<int>(shape_view.begin(), shape_view.end());
tensors.push_back(CreateTensor(*fbb, ExportVector<int32_t>(fbb, shape),
type, buffer_index,
fbb->CreateString(tensor->name),
quantization_params, tensor->is_variable));
}
}
return fbb->template CreateVector<flatbuffers::Offset<Tensor>>(tensors);
}
flatbuffers::Offset<flatbuffers::Vector<flatbuffers::Offset<Buffer>>>
SubgraphWriter::ExportBuffers(flatbuffers::FlatBufferBuilder* fbb) {
std::vector<flatbuffers::Offset<Buffer>> buffer_vector;
for (auto buffer : buffers_) {
auto data_offset = fbb->CreateVector(buffer.first, buffer.second);
buffer_vector.push_back(CreateBuffer(*fbb, data_offset));
}
return fbb->template CreateVector<flatbuffers::Offset<Buffer>>(buffer_vector);
}
flatbuffers::Offset<flatbuffers::Vector<flatbuffers::Offset<OperatorCode>>>
SubgraphWriter::CreateOpCodeTable(flatbuffers::FlatBufferBuilder* fbb) {
std::vector<flatbuffers::Offset<OperatorCode>> codes;
for (const auto& it : opcodes_) {
const char* custom_name = it.custom.empty() ? nullptr : it.custom.c_str();
codes.push_back(CreateOperatorCodeDirect(
*fbb, static_cast<BuiltinOperator>(it.builtin), custom_name));
}
return fbb->template CreateVector<flatbuffers::Offset<OperatorCode>>(codes);
}
template <class T>
std::vector<int> SubgraphWriter::RemapTensorIndicesToWritten(const T& input) {
std::vector<int> output;
output.reserve(input.size());
for (int x : input) {
// Special value representing an optional tensor which is not present.
if (x == -1) {
output.push_back(x);
continue;
}
if (tensor_to_written_tensor_[x] != -1) {
output.push_back(tensor_to_written_tensor_[x]);
}
}
return output;
}
TfLiteStatus SubgraphWriter::GetBuffer(std::unique_ptr<uint8_t[]>* out,
size_t* size) {
if (!out || !size) return kTfLiteError;
flatbuffers::FlatBufferBuilder builder(/*initial_size=*/10240);
std::vector<flatbuffers::Offset<SubGraph>> subgraphs_as_vector;
{ // subgraph specific stuff
auto tensors = ExportTensors(&builder);
std::vector<int> written_inputs = RemapTensorIndicesToWritten(inputs_);
std::vector<int> written_outputs = RemapTensorIndicesToWritten(outputs_);
auto inputs = ExportVector<int32_t>(&builder, written_inputs);
auto outputs = ExportVector<int32_t>(&builder, written_outputs);
auto ops = ExportOperators(&builder);
subgraphs_as_vector.push_back(
CreateSubGraph(builder, tensors, inputs, outputs, ops, /* name */ 0));
}
flatbuffers::Offset<flatbuffers::Vector<flatbuffers::Offset<Buffer>>>
buffers = ExportBuffers(&builder);
auto description = builder.CreateString("Exported from Subgraph.");
auto op_codes = CreateOpCodeTable(&builder);
auto model = CreateModel(builder, TFLITE_SCHEMA_VERSION, op_codes,
builder.CreateVector(subgraphs_as_vector),
description, buffers);
::tflite::FinishModelBuffer(builder, model);
const uint8_t* buffer = builder.GetBufferPointer();
*size = builder.GetSize();
(*out).reset(new uint8_t[*size]);
memcpy(out->get(), buffer, *size);
return kTfLiteOk;
}
TfLiteStatus SubgraphWriter::Write(const std::string& filename) {
std::unique_ptr<uint8_t[]> buffer;
size_t size;
TF_LITE_ENSURE_STATUS(GetBuffer(&buffer, &size));
FILE* fp = fopen(filename.c_str(), "wb");
if (!fp) return kTfLiteError;
if (fwrite(buffer.get(), 1, size, fp) != size) {
fclose(fp);
return kTfLiteError;
}
if (fclose(fp)) return kTfLiteError;
return kTfLiteOk;
}
TfLiteStatus SubgraphWriter::RegisterCustomWriter(
const std::string& custom_name, CustomWriter custom_writer) {
if (custom_op_to_writer_.find(custom_name) != custom_op_to_writer_.end()) {
return kTfLiteError;
}
custom_op_to_writer_.insert(std::make_pair(custom_name, custom_writer));
return kTfLiteOk;
}
TfLiteStatus SubgraphWriter::CheckInputOutput(
const std::vector<int>& inputs, const std::vector<int>& outputs,
const std::vector<int>& execution_plan) {
std::unordered_set<int> known_tensors(inputs.begin(), inputs.end());
// Scan execution plan and confirm input tensors are known before each node
// executes. Then append output tensors to known tensors.
for (int op_index : execution_plan) {
const auto* node_and_registration =
subgraph_->node_and_registration(op_index);
const TfLiteNode& node = node_and_registration->first;
for (int tensor_index : TfLiteIntArrayView(node.inputs)) {
if (TfLiteTensor* tensor = subgraph_->tensor(tensor_index)) {
// Skip constant tensors.
if (tensor->allocation_type == kTfLiteMmapRo) {
continue;
}
}
if (known_tensors.find(tensor_index) == known_tensors.end()) {
subgraph_->context()->ReportError(
subgraph_->context(),
"Node (%d) uses an input (%d) that is not provided.", op_index,
tensor_index);
return kTfLiteError;
}
}
TfLiteIntArrayView outputs(node.outputs);
known_tensors.insert(outputs.begin(), outputs.end());
}
// Check if outputs are known tensors or constants.
for (int tensor_index : outputs) {
if (TfLiteTensor* tensor = subgraph_->tensor(tensor_index)) {
// Skip constant tensors.
if (tensor->allocation_type == kTfLiteMmapRo) {
continue;
}
}
if (known_tensors.find(tensor_index) == known_tensors.end()) {
subgraph_->context()->ReportError(
subgraph_->context(),
"Output (%d) is not produced by the execution plan.", tensor_index);
return kTfLiteError;
}
}
return kTfLiteOk;
}
TfLiteStatus SubgraphWriter::SetCustomInputOutput(
const std::vector<int>& inputs, const std::vector<int>& outputs,
const std::vector<int>& execution_plan) {
TF_LITE_ENSURE_STATUS(CheckInputOutput(inputs, outputs, execution_plan));
inputs_ = inputs;
outputs_ = outputs;
execution_plan_ = execution_plan;
return kTfLiteOk;
}
} // namespace tflite