Switch TFLM quantize kernels to flat namespace.

This is incremental progress towards a flat namespace for TFLM. See
https://abseil.io/tips/130 for more context.

PiperOrigin-RevId: 335946049
Change-Id: Ie28a33927967798470825c2dfffd01dd926d0f40

tensorflow/lite/micro/kernels/micro_ops.h

@@ -33,6 +33,7 @@ namespace tflite {
 
 TfLiteRegistration Register_CONV_2D();
 TfLiteRegistration Register_DEPTHWISE_CONV_2D();
+TfLiteRegistration Register_QUANTIZE();
 TfLiteRegistration Register_SHAPE();
 
 namespace ops {
@@ -73,7 +74,6 @@ TfLiteRegistration Register_PACK();
 TfLiteRegistration Register_PAD();
 TfLiteRegistration Register_PADV2();
 TfLiteRegistration Register_PRELU();
-TfLiteRegistration Register_QUANTIZE();
 TfLiteRegistration Register_REDUCE_MAX();
 TfLiteRegistration Register_RELU();
 TfLiteRegistration Register_RELU6();

tensorflow/lite/micro/kernels/quantize.cc

@@ -23,9 +23,7 @@ limitations under the License.
 #include "tensorflow/lite/micro/micro_utils.h"
 
 namespace tflite {
-namespace ops {
+namespace {
-namespace micro {
-namespace quantize {
 
 struct OpData {
   tflite::QuantizationParams quantization_params;
@@ -175,22 +173,17 @@ TfLiteStatus Eval(TfLiteContext* context, TfLiteNode* node) {
   return kTfLiteOk;
 }
 
-}  // namespace quantize
+}  // namespace
 
-// This Op (QUANTIZE) quantizes the input and produces quantized output.
-// AffineQuantize takes scale and zero point and quantizes the float value to
-// quantized output, in int8_t or uint8_t format.
 TfLiteRegistration Register_QUANTIZE() {
-  return {/*init=*/quantize::Init,
+  return {/*init=*/Init,
           /*free=*/nullptr,
-          /*prepare=*/quantize::Prepare,
+          /*prepare=*/Prepare,
-          /*invoke=*/quantize::Eval,
+          /*invoke=*/Eval,
           /*profiling_string=*/nullptr,
           /*builtin_code=*/0,
           /*custom_name=*/nullptr,
           /*version=*/0};
 }
 
-}  // namespace micro
-}  // namespace ops
 }  // namespace tflite

tensorflow/lite/micro/kernels/quantize_test.cc

@@ -35,8 +35,7 @@ void ValidateQuantizeGoldens(TfLiteTensor* tensors, int tensors_size,
   TfLiteIntArray* outputs_array = IntArrayFromInts(outputs_array_data);
 
   // Version 1 of quantize supports int8_t and uint8_t quantization.
-  const TfLiteRegistration registration =
+  const TfLiteRegistration registration = Register_QUANTIZE();
-      tflite::ops::micro::Register_QUANTIZE();
   micro::KernelRunner runner(registration, tensors, tensors_size, inputs_array,
                              outputs_array,
                              /*builtin_data=*/nullptr, micro_test::reporter);

tensorflow/lite/micro/kernels/xtensa_hifimini/quantize.cc

@@ -25,11 +25,12 @@ limitations under the License.
 #include "tensorflow/lite/micro/kernels/xtensa_hifimini/fixedpoint_utils.h"
 
 namespace tflite {
-namespace ops {
+namespace {
-namespace micro {
 
-namespace xtensa {
+struct OpData {
-namespace hifimini {
+  int32_t zero_point = 0;
+  int scale_multiplier = 0;
+};
 
 void AffineQuantize(int scale_multiplier, const int32_t zero_point,
                     const RuntimeShape& input_shape, const int16_t* input_data,
@@ -98,16 +99,6 @@ void AffineQuantize(int scale_multiplier, const int32_t zero_point,
   }
 }
 
-}  // namespace hifimini
-}  // namespace xtensa
-
-namespace quantize {
-
-struct OpData {
-  int32_t zero_point = 0;
-  int scale_multiplier = 0;
-};
-
 void* Init(TfLiteContext* context, const char* buffer, size_t length) {
   TFLITE_DCHECK(context->AllocatePersistentBuffer != nullptr);
   return context->AllocatePersistentBuffer(context, sizeof(OpData));
@@ -121,7 +112,8 @@ TfLiteStatus Prepare(TfLiteContext* context, TfLiteNode* node) {
   const TfLiteTensor* input = GetInput(context, node, 0);
 
   // TODO(b/155682734): Fix dangerous input/output scale ratio assumptions.
-  op_data->scale_multiplier = xtensa::hifimini::CreateQConstantForInt24(
+  op_data->scale_multiplier =
+      ops::micro::xtensa::hifimini::CreateQConstantForInt24(
           0, input->params.scale / output->params.scale);
 
   op_data->zero_point = output->params.zero_point;
@@ -146,8 +138,7 @@ TfLiteStatus Eval(TfLiteContext* context, TfLiteNode* node) {
     return kTfLiteError;
   }
 
-  xtensa::hifimini::AffineQuantize(
+  AffineQuantize(op_data->scale_multiplier, op_data->zero_point,
-      op_data->scale_multiplier, op_data->zero_point,
                  tflite::micro::GetTensorShape(input),
                  tflite::micro::GetTensorData<int16_t>(input),
                  tflite::micro::GetTensorShape(output),
@@ -155,22 +146,17 @@ TfLiteStatus Eval(TfLiteContext* context, TfLiteNode* node) {
   return kTfLiteOk;
 }
 
-}  // namespace quantize
+}  // namespace
 
-// This Op (QUANTIZE) quantizes the input and produces quantized output.
-// AffineQuantize takes scale and zero point and quantizes the float value to
-// quantized output, in int8_t or uint8_t format.
 TfLiteRegistration Register_QUANTIZE() {
-  return {/*init=*/quantize::Init,
+  return {/*init=*/Init,
           /*free=*/nullptr,
-          /*prepare=*/quantize::Prepare,
+          /*prepare=*/Prepare,
-          /*invoke=*/quantize::Eval,
+          /*invoke=*/Eval,
           /*profiling_string=*/nullptr,
           /*builtin_code=*/0,
           /*custom_name=*/nullptr,
           /*version=*/0};
 }
 
-}  // namespace micro
-}  // namespace ops
 }  // namespace tflite

tensorflow/lite/micro/micro_mutable_op_resolver.h

@@ -303,8 +303,8 @@ class MicroMutableOpResolver : public MicroOpResolver {
   }
 
   TfLiteStatus AddQuantize() {
-    return AddBuiltin(BuiltinOperator_QUANTIZE,
+    return AddBuiltin(BuiltinOperator_QUANTIZE, Register_QUANTIZE(),
-                      tflite::ops::micro::Register_QUANTIZE(), ParseQuantize);
+                      ParseQuantize);
   }
 
   TfLiteStatus AddReduceMax() {