78 lines
3.5 KiB
OCaml
78 lines
3.5 KiB
OCaml
(* This module exposes an [interpret] function to Rust. It wraps several different calls from the
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WebAssembly specification interpreter in a way that we can access across the FFI boundary. To
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understand this better, see:
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- the OCaml manual documentation re: calling OCaml from C, https://ocaml.org/manual/intfc.html#s%3Ac-advexample
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- the [ocaml-interop] example, https://github.com/tezedge/ocaml-interop/blob/master/testing/rust-caller/ocaml/callable.ml
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*)
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(* Here we access the WebAssembly specification interpreter; this must be linked in. *)
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open Wasm
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open Wasm.WasmRef_Isa_m.WasmRef_Isa
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(** Enumerate the types of values we pass across the FFI boundary. This must match `Value` in
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`src/lib.rs` *)
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type ffi_value =
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| I32 of int32
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| I64 of int64
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| F32 of int32
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| F64 of int64
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| V128 of Bytes.t
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(** Helper for converting the FFI values to their spec interpreter type. *)
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let convert_to_wasm (v: ffi_value) : v = match v with
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| I32 n -> V_num (ConstInt32 (I32_impl_abs n))
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| I64 n -> V_num (ConstInt64 (I64_impl_abs n))
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| F32 n -> V_num (ConstFloat32 (F32.of_bits n))
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| F64 n -> V_num (ConstFloat64 (F64.of_bits n))
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| V128 n -> V_vec (ConstVec128 (V128.of_bits (Bytes.to_string n)))
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(** Helper for converting the spec interpreter values to their FFI type. *)
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let convert_from_wasm (v: v) : ffi_value = match v with
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| V_num ((ConstInt32 (I32_impl_abs n))) -> I32 n
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| V_num ((ConstInt64 (I64_impl_abs n))) -> I64 n
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| V_num ((ConstFloat32 n)) -> F32 (F32.to_bits n)
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| V_num ((ConstFloat64 n)) -> F64 (F64.to_bits n)
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| V_vec ((ConstVec128 n)) -> V128 (Bytes.of_string (V128.to_bits n))
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| _ -> failwith "Unknown type"
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(** Parse the given WebAssembly module binary into an Ast.module_. At some point in the future this
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should also be able to parse the textual form (TODO). *)
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let parse bytes =
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(* Optionally, use Bytes.unsafe_to_string here to avoid the copy *)
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let bytes_as_str = Bytes.to_string bytes in
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(Decode.decode "default" bytes_as_str)
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(** Return true if an export is a function. *)
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let match_exported_func export = match export with
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| Module_export_ext(_,Ext_func n,_) -> true
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| _ -> false
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(** Extract a function from its export or fail. *)
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let extract_exported_func export = match export with
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| Module_export_ext(_,Ext_func n,_) -> n
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| _ -> failwith ""
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(** Interpret the first exported function and return the result. Use provided
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parameters if they exist, otherwise use default (zeroed) values. *)
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let interpret_exn module_bytes opt_params =
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let opt_params_ = Option.map (List.map convert_to_wasm) opt_params in
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let module_ = parse module_bytes in
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let m_isa = Ast_convert.convert_module (module_.it) in
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let fuel = Z.of_string "4611686018427387904" in
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let max_call_depth = Z.of_string "300" in
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(match run_fuzz (nat_of_integer fuel) (nat_of_integer max_call_depth) (make_empty_store_m ()) m_isa [] opt_params_ () with
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| (s', RValue vs_isa') -> List.rev_map convert_from_wasm vs_isa'
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| (s', RTrap str) -> raise (Eval.Trap (Source.no_region, "(Isabelle) trap: " ^ str))
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| (s', (RCrash (Error_exhaustion str))) -> raise (Eval.Exhaustion (Source.no_region, "(Isabelle) call stack exhausted"))
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| (s', (RCrash (Error_invalid str))) -> raise (Eval.Crash (Source.no_region, "(Isabelle) error: " ^ str))
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| (s', (RCrash (Error_invariant str))) -> raise (Eval.Crash (Source.no_region, "(Isabelle) error: " ^ str))
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(* TODO eventually we should hash the memory state and return the hash *)
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)
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let interpret module_bytes opt_params =
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try Ok(interpret_exn module_bytes opt_params) with
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| _ as e -> Error(Printexc.to_string e)
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let () =
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Callback.register "interpret" interpret;
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