Source file michelson_v1_gas_costs.ml

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include Michelson_v1_gas_costs_generated
module S = Saturation_repr

(** Hand-edited/written cost functions *)

(* Functions to be replaced by the generated code.

   The codegen cannot generate exactly the same code here. They have to
   be replaced by the generated versions.
*)

(* generated code is not usable: the const is not on a grid point *)
(* model N_ILsl_nat *)
(* Allocates at most [size + 256] bytes *)
let cost_N_ILsl_nat size =
  let open S.Syntax in
  let v0 = S.safe_int size in
  S.safe_int 128 + (v0 lsr 1)

(* generated code is not usable: the actual code and the model differ *)
(* model N_ILsl_bytes *)
(* Allocates [size + shift / 8] bytes *)
(* fun size1 -> fun size2 -> ((63.0681507316 + (0.667539714647 * size1)) + (0. * size2)) *)
let cost_N_ILsl_bytes size shift =
  let open S.Syntax in
  let v1 = S.safe_int size in
  let v0 = S.safe_int shift in
  S.safe_int 65 + (v1 lsr 1) + (v1 lsr 2) + (v0 lsr 4)

(* ------------------------------------------------------------------------ *)

(* N_ISapling_verify_update_with_blake2b
   This function depends on another cost function cost_N_IBlake2b.
   Such code can't be generated by the current Snoop. *)
let cost_N_ISapling_verify_update_with_blake2b size1 size2 bound_data =
  let open S.Syntax in
  cost_N_IBlake2b bound_data + cost_N_ISapling_verify_update size1 size2

(* N_IApply
   The current generated model receives int as a flag,
   but it should receive bool. *)
(* model N_IApply *)
(* fun size -> if (size = 0) then 140 else 220 *)
let cost_N_IApply rec_flag = if rec_flag then S.safe_int 220 else S.safe_int 140

(* N_KMap_enter_body
   Removed conversion of [size] for optimization *)
(* model N_KMap_enter_body *)
let cost_N_KMap_enter_body size =
  if Compare.Int.(size = 0) then S.safe_int 10 else S.safe_int 80

(* N_KList_enter_body
   The generated model receives the length of `xs` as the first argument
   and branches on whether it is 0 or not.
   However, calculating the length makes the performance worse.
   The model should be changed to receive `xs_is_nil` as the first argument. *)
(* model N_KList_enter_body *)
(* Approximating 1.797068 x term *)
let cost_N_KList_enter_body xs size_ys =
  match xs with
  | [] ->
      let open S.Syntax in
      let v0 = S.safe_int size_ys in
      S.safe_int 30 + (v0 + (v0 lsr 1) + (v0 lsr 2) + (v0 lsr 4))
  | _ :: _ -> S.safe_int 30

(* model PARSE_TYPE
   This is the cost of one iteration of parse_ty, extracted by hand from the
   parameter fit for the PARSE_TYPE benchmark. *)
let cost_PARSE_TYPE1 = cost_PARSE_TYPE 1

(* model TYPECHECKING_CODE
   This is the cost of one iteration of parse_instr, extracted by hand from the
   parameter fit for the TYPECHECKING_CODE benchmark. *)
let cost_TYPECHECKING_CODE = S.safe_int 220

(* model UNPARSING_CODE
   This is the cost of one iteration of unparse_instr, extracted by hand from the
   parameter fit for the UNPARSING_CODE benchmark. *)
let cost_UNPARSING_CODE = S.safe_int 115

(* model TYPECHECKING_DATA
   This is the cost of one iteration of parse_data, extracted by hand from the
   parameter fit for the TYPECHECKING_DATA benchmark. *)
let cost_TYPECHECKING_DATA = S.safe_int 100

(* model UNPARSING_DATA
   This is the cost of one iteration of unparse_data, extracted by hand from the
   parameter fit for the UNPARSING_DATA benchmark. *)
let cost_UNPARSING_DATA = S.safe_int 65

(* TODO: https://gitlab.com/tezos/tezos/-/issues/2264
   Benchmark.
   Currently approximated by 2 comparisons of the longest entrypoint. *)
let cost_FIND_ENTRYPOINT = cost_N_ICompare 31 31

(* ------------------------------------------------------------------------ *)

(* These functions lack the corresponding models. *)

(* model SAPLING_TRANSACTION_ENCODING *)
let cost_SAPLING_TRANSACTION_ENCODING ~inputs ~outputs ~bound_data =
  S.safe_int (1500 + (inputs * 160) + (outputs * 320) + (bound_data lsr 3))

(* model SAPLING_DIFF_ENCODING *)
let cost_SAPLING_DIFF_ENCODING ~nfs ~cms = S.safe_int ((nfs * 22) + (cms * 215))

(* ------------------------------------------------------------------------ *)

(* IDropN and IDupN use non affine models with multiple cases. The inferred
   cost functions are more complex than the following affine functions. *)

(* model N_IDropN *)
(* Approximating 2.713108 x term *)
let cost_N_IDropN size =
  let open S.Syntax in
  let v0 = S.safe_int size in
  S.safe_int 30 + (S.safe_int 2 * v0) + (v0 lsr 1) + (v0 lsr 3)

(* model N_IDupN *)
(* Approximating 1.222263 x term *)
let cost_N_IDupN size =
  let open S.Syntax in
  let v0 = S.safe_int size in
  S.safe_int 20 + v0 + (v0 lsr 2)

(* ------------------------------------------------------------------------ *)

(* Following functions are partially carbonated: they charge some gas
   by themselves.  Their inferred gas parameters cannot be directly
   used since they should contain the partial carbonation.
*)

(* model N_IContract *)
(* Inferred value: 703.26072741 *)
(* Most computation happens in [parse_contract_for_script], which is
   carbonated. *)
let cost_N_IContract = S.safe_int 30

(* model N_ICreate_contract *)
(* Inferred value: 814.154060743 *)
(* Most computation happens in [create_contract], which is carbonated. *)
let cost_N_ICreate_contract = S.safe_int 60

(* model N_ITransfer_tokens *)
(* Inferred value: 230.707394077 *)
(* Most computation happens in [transfer], which is carbonated. *)
let cost_N_ITransfer_tokens = S.safe_int 60

(* model IEmit *)
(* Inferred value: 244.687394077 *)
(* Most computation happens in [emit_event], which is carbonated. *)
let cost_N_IEmit = S.safe_int 30

(* --------------------------------------------------------------------- *)

(* The cost functions below where not benchmarked, a cost model was derived
    from looking at similar instructions. *)
(* Cost for Concat_string is paid in two steps: when entering the interpreter,
    the user pays for the cost of computing the information necessary to compute
    the actual gas (so it's meta-gas): indeed, one needs to run through the
    list of strings to compute the total allocated cost.
    [concat_string_precheck] corresponds to the meta-gas cost of this computation.
*)

let cost_N_IConcat_string_precheck length =
  (* we set the precheck to be slightly more expensive than cost_N_IList_iter *)
  let open S.Syntax in
  let length = S.safe_int length in
  length * S.safe_int 10

(* This is the cost of allocating a string and blitting existing ones into it. *)
let cost_N_IConcat_string total_bytes =
  let open S.Syntax in
  S.safe_int 100 + (total_bytes lsr 1)

(* Same story as Concat_string. *)
let cost_N_IConcat_bytes total_bytes =
  let open S.Syntax in
  S.safe_int 100 + (total_bytes lsr 1)

(* A partially carbonated instruction,
   so its model does not correspond to this function *)
(* Cost of Unpack pays two integer comparisons, and a Bytes slice *)
let cost_N_IUnpack total_bytes =
  let open S.Syntax in
  let total_bytes = S.safe_int total_bytes in
  S.safe_int 260 + (total_bytes lsr 1)