(*===-- llvm_executionengine.mli - LLVM Ocaml Interface ---------*- C++ -*-===*
 *
 *                     The LLVM Compiler Infrastructure
 *
 * This file is distributed under the University of Illinois Open Source
 * License. See LICENSE.TXT for details.
 *
 *===----------------------------------------------------------------------===*)

(** JIT Interpreter.

    This interface provides an ocaml API for LLVM execution engine (JIT/
    interpreter), the classes in the ExecutionEngine library. *)

exception Error of string

module GenericValue: sig
  (** [GenericValue.t] is a boxed union type used to portably pass arguments to
      and receive values from the execution engine. It supports only a limited
      selection of types; for more complex argument types, it is necessary to
      generate a stub function by hand or to pass parameters by reference.
      See the struct [llvm::GenericValue]. *)
  type t
  
  (** [of_float fpty n] boxes the float [n] in a float-valued generic value
      according to the floating point type [fpty]. See the fields
      [llvm::GenericValue::DoubleVal] and [llvm::GenericValue::FloatVal]. *)
  val of_float: Llvm.lltype -> float -> t
  
  (** [of_pointer v] boxes the pointer value [v] in a generic value. See the
      field [llvm::GenericValue::PointerVal]. *)
  val of_pointer: 'a -> t
  
  (** [of_int32 n w] boxes the int32 [i] in a generic value with the bitwidth
      [w]. See the field [llvm::GenericValue::IntVal]. *)
  val of_int32: Llvm.lltype -> int32 -> t
  
  (** [of_int n w] boxes the int [i] in a generic value with the bitwidth
      [w]. See the field [llvm::GenericValue::IntVal]. *)
  val of_int: Llvm.lltype -> int -> t
  
  (** [of_natint n w] boxes the native int [i] in a generic value with the
      bitwidth [w]. See the field [llvm::GenericValue::IntVal]. *)
  val of_nativeint: Llvm.lltype -> nativeint -> t
  
  (** [of_int64 n w] boxes the int64 [i] in a generic value with the bitwidth
      [w]. See the field [llvm::GenericValue::IntVal]. *)
  val of_int64: Llvm.lltype -> int64 -> t
  
  (** [as_float fpty gv] unboxes the floating point-valued generic value [gv] of
      floating point type [fpty]. See the fields [llvm::GenericValue::DoubleVal]
      and [llvm::GenericValue::FloatVal]. *)
  val as_float: Llvm.lltype -> t -> float
  
  (** [as_pointer gv] unboxes the pointer-valued generic value [gv]. See the
      field [llvm::GenericValue::PointerVal]. *)
  val as_pointer: t -> 'a
  
  (** [as_int32 gv] unboxes the integer-valued generic value [gv] as an [int32].
      Is invalid if [gv] has a bitwidth greater than 32 bits. See the field
      [llvm::GenericValue::IntVal]. *)
  val as_int32: t -> int32
  
  (** [as_int gv] unboxes the integer-valued generic value [gv] as an [int].
      Is invalid if [gv] has a bitwidth greater than the host bit width (but the
      most significant bit may be lost). See the field
      [llvm::GenericValue::IntVal]. *)
  val as_int: t -> int
  
  (** [as_natint gv] unboxes the integer-valued generic value [gv] as a
      [nativeint]. Is invalid if [gv] has a bitwidth greater than
      [nativeint]. See the field [llvm::GenericValue::IntVal]. *)
  val as_nativeint: t -> nativeint
  
  (** [as_int64 gv] returns the integer-valued generic value [gv] as an [int64].
      Is invalid if [gv] has a bitwidth greater than [int64]. See the field
      [llvm::GenericValue::IntVal]. *)
  val as_int64: t -> int64
end


module ExecutionEngine: sig
  (** An execution engine is either a JIT compiler or an interpreter, capable of
      directly loading an LLVM module and executing its functions without first
      invoking a static compiler and generating a native executable. *)
  type t
  
  (** [create mp] creates a new execution engine, taking ownership of the
      module provider [mp] if successful. Creates a JIT if possible, else falls
      back to an interpreter. Raises [Error msg] if an error occurrs. The
      execution engine is not garbage collected and must be destroyed with
      [dispose ee]. See the function [llvm::ExecutionEngine::create]. *)
  val create: Llvm.llmoduleprovider -> t
  
  (** [create_interpreter mp] creates a new interpreter, taking ownership of the
      module provider [mp] if successful. Raises [Error msg] if an error
      occurrs. The execution engine is not garbage collected and must be
      destroyed with [dispose ee].
      See the function [llvm::ExecutionEngine::create]. *)
  val create_interpreter: Llvm.llmoduleprovider -> t
  
  (** [create_jit mp] creates a new JIT (just-in-time compiler), taking
      ownership of the module provider [mp] if successful. Raises [Error msg] if
      an error occurrs. The execution engine is not garbage collected and must
      be destroyed with [dispose ee].
      See the function [llvm::ExecutionEngine::create]. *)
  val create_jit: Llvm.llmoduleprovider -> t
  
  (** [dispose ee] releases the memory used by the execution engine and must be
      invoked to avoid memory leaks. *)
  val dispose: t -> unit
  
  (** [add_module_provider mp ee] adds the module provider [mp] to the execution
      engine [ee]. *)
  val add_module_provider: Llvm.llmoduleprovider -> t -> unit
  
  (** [remove_module_provider mp ee] removes the module provider [mp] from the
      execution engine [ee], disposing of [mp] and the module referenced by
      [mp]. Raises [Error msg] if an error occurs. *)
  val remove_module_provider: Llvm.llmoduleprovider -> t -> Llvm.llmodule
  
  (** [find_function n ee] finds the function named [n] defined in any of the
      modules owned by the execution engine [ee]. Returns [None] if the function
      is not found and [Some f] otherwise. *)
  val find_function: string -> t -> Llvm.llvalue option
  
  (** [run_function f args ee] synchronously executes the function [f] with the
      arguments [args], which must be compatible with the parameter types. *)
  val run_function: Llvm.llvalue -> GenericValue.t array -> t ->
                    GenericValue.t
  
  (** [run_static_ctors ee] executes the static constructors of each module in
      the execution engine [ee]. *)
  val run_static_ctors: t -> unit
  
  (** [run_static_dtors ee] executes the static destructors of each module in
      the execution engine [ee]. *)
  val run_static_dtors: t -> unit
  
  (** [run_function_as_main f args env ee] executes the function [f] as a main
      function, passing it [argv] and [argc] according to the string array
      [args], and [envp] as specified by the array [env]. Returns the integer
      return value of the function. *)
  val run_function_as_main: Llvm.llvalue -> string array ->
                            (string * string) array -> t -> int
  
  (** [free_machine_code f ee] releases the memory in the execution engine [ee]
      used to store the machine code for the function [f]. *)
  val free_machine_code: Llvm.llvalue -> t -> unit
end