schema/bundled_program_schema.fbs

// Copyright (c) Meta Platforms, Inc. and affiliates.

//
// See README.md before modifying this file.
//

include "scalar_type.fbs";

namespace bundled_program_flatbuffer;

// Identifier of a valid bundled program schema.
file_identifier "BP06";
// Extension of written files.
file_extension "bpte";

// Reason for basic struct: union value type can only be table/struct/string
table Int {
  int_val:long;
}

table Bool {
  bool_val:bool;
}

table Double {
  double_val:double;
}

// All information we need to bundle for a tensor EValue input.
table Tensor {
  // The scalar type of Tensor
  scalar_type: executorch_flatbuffer.ScalarType;
  // The target sizes of the tensor.
  sizes: [int];
  // The contents of the corresponding input tensor.
  data: [ubyte] (force_align: 16);
  dim_order:[ubyte];
}

union ValueUnion {
  Tensor,
  Int,
  Bool,
  Double,
}

// Abstraction for BundledIOSet values
table Value {
  val: ValueUnion;
}

// All inputs and referenced outputs needs for single verification.
table BundledIOSet {
  // All inputs required by Program for execution. Its length should be
  // equal to the length of program inputs.
  inputs: [Value];

  // The expected outputs generated while running the model in eager mode
  // using the inputs provided. Its length should be equal to the length
  // of program outputs.
  expected_outputs: [Value];
}


// Context for testing and verifying an exceution plan.
table BundledExecutionPlanTest {

  // The name of the method to test; e.g., "forward" for the forward() method
  // of an nn.Module. This name match a method defined by the ExecuTorch
  // program.
  method_name: string;

  // Sets of input/outputs to test with.
  test_sets: [BundledIOSet];
}

// Executorch program bunlded with data for verification.
table BundledProgram {
  // Schema version.
  version:uint;

  // Test sets and other meta datas to verify the whole program.
  // Each BundledExecutionPlanTest should be used for the execution plan of program sharing same index.
  // Its length should be equal to the number of execution plans in program.
  execution_plan_tests: [BundledExecutionPlanTest];

  // The binary data of a serialized Executorch program.
  // The following `force_align` may sliently override any larger force_align
  // used in the program. Therefore, to keep the data (including constant
  // tensor, delegate data, etc, see schema.fbs for more info) in the
  // executorch program keeps the same alignment as original no matter how
  // the program schema changes, we need to make the force_align here the max
  // one around all kinds of force_align in the current and future program
  // schema, so we use the 16, the largest possible alignment of flatbuffer,
  // as the force_align here.
  // In the future, we may need to revisit that to enforce larger alignment
  // constraint. If needed, check against FLATBUFFERS_MAX_ALIGNMENT in the
  // flatbuffers/base.h, which is the given alignment ceiling of flatbuffer.
  program: [ubyte] (force_align: 16);
}

root_type BundledProgram;