TFLM: Move forward with the original CL and fix bluepill test by adding -fno-threadsafe-statics flag.

PiperOrigin-RevId: 302606302
Change-Id: Iaff9548f5aa7bbdfc81b981b300098f5c3ed8dea

tensorflow/lite/micro/kernels/fully_connected.cc

@@ -71,18 +71,35 @@ TfLiteStatus CalculateOpData(TfLiteContext* context,
 }  // namespace
 
 void* Init(TfLiteContext* context, const char* buffer, size_t length) {
-  return nullptr;
+  OpData* data = nullptr;
+  TfLiteStatus status = context->AllocatePersistentBuffer(
+      context, sizeof(OpData), reinterpret_cast<void**>(&data));
+  if (status != kTfLiteOk || data == nullptr) {
+    return nullptr;
+  }
+  return data;
 }
 
 void Free(TfLiteContext* context, void* buffer) {}
 
 TfLiteStatus Prepare(TfLiteContext* context, TfLiteNode* node) {
+  OpData* data = reinterpret_cast<OpData*>(node->user_data);
+  auto* params =
+      reinterpret_cast<TfLiteFullyConnectedParams*>(node->builtin_data);
+
   const TfLiteTensor* input = GetInput(context, node, kInputTensor);
   const TfLiteTensor* filter = GetInput(context, node, kWeightsTensor);
+  const TfLiteTensor* bias = GetOptionalInputTensor(context, node, kBiasTensor);
   TfLiteTensor* output = GetOutput(context, node, kOutputTensor);
+
   TF_LITE_ENSURE_EQ(context, input->type, output->type);
   TF_LITE_ENSURE_MSG(context, input->type == filter->type,
                      "Hybrid models are not supported on TFLite Micro.");
+
+  TfLiteType data_type = input->type;
+  TF_LITE_ENSURE_STATUS(CalculateOpData(context, params, data_type, input,
+                                        filter, bias, output, data));
+
   return kTfLiteOk;
 }
 
@@ -178,11 +195,7 @@ TfLiteStatus Eval(TfLiteContext* context, TfLiteNode* node) {
   const TfLiteTensor* bias = GetOptionalInputTensor(context, node, kBiasTensor);
   TfLiteTensor* output = GetOutput(context, node, kOutputTensor);
 
-  TfLiteType data_type = input->type;
-  OpData local_data_object;
-  OpData* data = &local_data_object;
-  TF_LITE_ENSURE_STATUS(CalculateOpData(context, params, data_type, input,
-                                        filter, bias, output, data));
+  OpData* data = reinterpret_cast<OpData*>(node->user_data);
 
   // Checks in Prepare ensure input, output and filter types are all the same.
   switch (input->type) {

tensorflow/lite/micro/kernels/fully_connected_test.cc

@@ -49,7 +49,6 @@ void TestFullyConnectedFloat(
 
   TfLiteContext context;
   PopulateContext(tensors, tensors_size, micro_test::reporter, &context);
-
   ::tflite::ops::micro::AllOpsResolver resolver;
   const TfLiteRegistration* registration =
       resolver.FindOp(tflite::BuiltinOperator_FULLY_CONNECTED, 1);

tensorflow/lite/micro/test_helpers.h

@@ -58,9 +58,6 @@ CreateFlatbufferBuffers();
 // Performs a simple string comparison without requiring standard C library.
 int TestStrcmp(const char* a, const char* b);
 
-// Wrapper to forward kernel errors to the interpreter's error reporter.
-void ReportOpError(struct TfLiteContext* context, const char* format, ...);
-
 void PopulateContext(TfLiteTensor* tensors, int tensors_size,
                      TfLiteContext* context);
 

tensorflow/lite/micro/testing/BUILD

@@ -17,6 +17,7 @@ cc_library(
     deps = [
         "//tensorflow/lite/c:common",
         "//tensorflow/lite/core/api",
+        "//tensorflow/lite/kernels/internal:compatibility",
         "//tensorflow/lite/micro:micro_framework",
         "//tensorflow/lite/micro:micro_utils",
     ],

tensorflow/lite/micro/testing/test_utils.cc

@@ -15,24 +15,107 @@ limitations under the License.
 
 #include "tensorflow/lite/micro/testing/test_utils.h"
 
+#include "tensorflow/lite/kernels/internal/compatibility.h"
+
 namespace tflite {
 namespace testing {
 
+TfLiteStatus FakeAllocator::AllocatePersistentBuffer(size_t bytes, void** ptr) {
+  uint8_t* addr = memory_allocator_->AllocateFromTail(bytes, kBufferAlignment);
+  *ptr = addr;
+  return kTfLiteOk;
+}
+
+TfLiteStatus FakeAllocator::RequestScratchBufferInArena(int node_idx,
+                                                        size_t bytes,
+                                                        int* buffer_idx) {
+  if (scratch_buffers_count_ >= max_scratch_buffers_count_) {
+    return kTfLiteError;
+  }
+  uint8_t* ptr = memory_allocator_->AllocateFromTail(bytes, kBufferAlignment);
+  scratch_buffers_[scratch_buffers_count_] = ptr;
+  *buffer_idx = scratch_buffers_count_;
+  scratch_buffers_count_++;
+  return kTfLiteOk;
+}
+
+void FakeAllocator::Reset() {
+  // Get A fresh memory allocator.
+  memory_allocator_ = CreateInPlaceSimpleMemoryAllocator(arena_, arena_size_);
+  TFLITE_DCHECK_NE(memory_allocator_, nullptr);
+
+  // Allocate enough space holding pointers to the scrtach buffers.
+  scratch_buffers_ =
+      reinterpret_cast<uint8_t**>(memory_allocator_->AllocateFromTail(
+          sizeof(uint8_t*) * max_scratch_buffers_count_, alignof(uint8_t*)));
+  TFLITE_DCHECK_NE(scratch_buffers_, nullptr);
+
+  scratch_buffers_count_ = 0;
+}
+
+void* FakeAllocator::GetScratchBuffer(int buffer_idx) {
+  if (buffer_idx < 0 || buffer_idx >= scratch_buffers_count_) {
+    return nullptr;
+  }
+  return scratch_buffers_[buffer_idx];
+}
+
+TfLiteStatus FakeContextHelper::AllocatePersistentBuffer(TfLiteContext* ctx,
+                                                         size_t bytes,
+                                                         void** ptr) {
+  return reinterpret_cast<FakeContextHelper*>(ctx->impl_)
+      ->allocator_->AllocatePersistentBuffer(bytes, ptr);
+}
+
+TfLiteStatus FakeContextHelper::RequestScratchBufferInArena(TfLiteContext* ctx,
+                                                            size_t bytes,
+                                                            int* buffer_idx) {
+  FakeContextHelper* helper = reinterpret_cast<FakeContextHelper*>(ctx->impl_);
+  // FakeAllocator doesn't do memory reusing so it doesn't need node_idx to
+  // calculate the lifetime of the scratch buffer.
+  int node_idx = -1;
+  return helper->allocator_->RequestScratchBufferInArena(node_idx, bytes,
+                                                         buffer_idx);
+}
+
+void* FakeContextHelper::GetScratchBuffer(TfLiteContext* ctx, int buffer_idx) {
+  return reinterpret_cast<FakeContextHelper*>(ctx->impl_)
+      ->allocator_->GetScratchBuffer(buffer_idx);
+}
+
+void FakeContextHelper::ReportOpError(struct TfLiteContext* context,
+                                      const char* format, ...) {
+  FakeContextHelper* helper = static_cast<FakeContextHelper*>(context->impl_);
+  va_list args;
+  va_start(args, format);
+  TF_LITE_REPORT_ERROR(helper->error_reporter_, format, args);
+  va_end(args);
+}
+
+namespace {
+constexpr size_t kArenaSize = 10000;
+constexpr int kMaxScratchBufferCount = 32;
+uint8_t arena[kArenaSize];
+}  // namespace
+
 // TODO(b/141330728): Move this method elsewhere as part clean up.
 void PopulateContext(TfLiteTensor* tensors, int tensors_size,
                      ErrorReporter* error_reporter, TfLiteContext* context) {
+  // This should be a large enough arena for each test cases.
+  static FakeAllocator allocator(arena, kArenaSize, kMaxScratchBufferCount);
+  static FakeContextHelper helper(error_reporter, &allocator);
+  // Reset the allocator so that it's ready for another test.
+  allocator.Reset();
+
+  *context = {};
+  context->recommended_num_threads = 1;
   context->tensors_size = tensors_size;
   context->tensors = tensors;
-  context->impl_ = static_cast<void*>(error_reporter);
-  context->GetExecutionPlan = nullptr;
-  context->ResizeTensor = nullptr;
-  context->ReportError = ReportOpError;
-  context->AddTensors = nullptr;
-  context->GetNodeAndRegistration = nullptr;
-  context->ReplaceNodeSubsetsWithDelegateKernels = nullptr;
-  context->recommended_num_threads = 1;
-  context->GetExternalContext = nullptr;
-  context->SetExternalContext = nullptr;
+  context->impl_ = static_cast<void*>(&helper);
+  context->AllocatePersistentBuffer = helper.AllocatePersistentBuffer;
+  context->RequestScratchBufferInArena = helper.RequestScratchBufferInArena;
+  context->GetScratchBuffer = helper.GetScratchBuffer;
+  context->ReportError = helper.ReportOpError;
 
   for (int i = 0; i < tensors_size; ++i) {
     if (context->tensors[i].is_variable) {

tensorflow/lite/micro/testing/test_utils.h

@@ -23,6 +23,7 @@ limitations under the License.
 #include "tensorflow/lite/c/common.h"
 #include "tensorflow/lite/core/api/tensor_utils.h"
 #include "tensorflow/lite/micro/micro_utils.h"
+#include "tensorflow/lite/micro/simple_memory_allocator.h"
 #include "tensorflow/lite/micro/test_helpers.h"
 #include "tensorflow/lite/micro/testing/micro_test.h"
 
@@ -95,7 +96,67 @@ inline int32_t F2Q32(const float value, const float scale) {
   return static_cast<int>(quantized);
 }
 
-// TODO(b/141330728): Move this method elsewhere as part clean up.
+// A fake version of MemoryAllocator that allocates everything from the tail
+// without static memory planning or reusing.
+// TODO(b/150260678): Consider splitting this into its own file and inherit from
+// the same public interface as MicroAllocator.
+class FakeAllocator {
+ public:
+  FakeAllocator(uint8_t* arena, size_t arena_size,
+                size_t max_scratch_buffers_count)
+      : arena_(arena),
+        arena_size_(arena_size),
+        max_scratch_buffers_count_(max_scratch_buffers_count) {
+    Reset();
+  }
+
+  TfLiteStatus AllocatePersistentBuffer(size_t bytes, void** ptr);
+  TfLiteStatus RequestScratchBufferInArena(int node_idx, size_t bytes,
+                                           int* buffer_idx);
+  void* GetScratchBuffer(int buffer_idx);
+
+  // Reset the allocator to the intial state.
+  void Reset();
+
+ private:
+  uint8_t* arena_;
+  size_t arena_size_;
+  size_t max_scratch_buffers_count_;
+
+  SimpleMemoryAllocator* memory_allocator_;
+  // An array of buffer pointers.
+  uint8_t** scratch_buffers_;
+  size_t scratch_buffers_count_ = 0;
+  static constexpr size_t kBufferAlignment = 16;
+};
+
+// A fake implementation of ContextHelper. Instead of forwarding requests to
+// MicroAllocator, it calls into FakeAllocator.
+// PopulateContext will point context->impl_ to an instance of this class.
+// TODO(b/150260678): Consider moving this into the same file as FakeAllocator.
+class FakeContextHelper {
+ public:
+  explicit FakeContextHelper(ErrorReporter* error_reporter,
+                             FakeAllocator* allocator)
+      : allocator_(allocator), error_reporter_(error_reporter) {}
+
+  static TfLiteStatus AllocatePersistentBuffer(TfLiteContext* ctx, size_t bytes,
+                                               void** ptr);
+
+  static TfLiteStatus RequestScratchBufferInArena(TfLiteContext* ctx,
+                                                  size_t bytes,
+                                                  int* buffer_idx);
+
+  static void* GetScratchBuffer(TfLiteContext* ctx, int buffer_idx);
+
+  static void ReportOpError(struct TfLiteContext* context, const char* format,
+                            ...);
+
+ private:
+  FakeAllocator* allocator_;
+  ErrorReporter* error_reporter_;
+};
+
 void PopulateContext(TfLiteTensor* tensors, int tensors_size,
                      ErrorReporter* error_reporter, TfLiteContext* context);
 

tensorflow/lite/micro/tools/make/targets/bluepill_makefile.inc

@@ -38,6 +38,7 @@ ifeq ($(TARGET), bluepill)
     -Wno-unused-parameter \
     -Wno-write-strings \
     -fno-delete-null-pointer-checks \
+    -fno-threadsafe-statics \
     -fomit-frame-pointer \
     -fpermissive \
     -nostdlib \