Require Import Coqlib Maps Errors Integers Floats.
Require Import AST Linking.
Require Import Ctypes Cop Clight Cminor Csharpminor.
Require Import Conventions1.

Local Open Scope string_scope.
Local Open Scope error_monad_scope.

Csharpminor constructors

Definition make_intconst (n: int) := Econst (Ointconst n).

Definition make_longconst (f: int64) := Econst (Olongconst f).

Definition make_floatconst (f: float) := Econst (Ofloatconst f).

Definition make_singleconst (f: float32) := Econst (Osingleconst f).

Definition make_ptrofsconst (n: Z) :=
  if Archi.ptr64 then make_longconst (Int64.repr n) else make_intconst (Int.repr n).

Definition make_singleoffloat (e: expr) := Eunop Osingleoffloat e.
Definition make_floatofsingle (e: expr) := Eunop Ofloatofsingle e.

Definition make_floatofint (e: expr) (sg: signedness) :=
  match sg with
  | Signed => Eunop Ofloatofint e
  | Unsigned => Eunop Ofloatofintu e
  end.

Definition make_singleofint (e: expr) (sg: signedness) :=
  match sg with
  | Signed => Eunop Osingleofint e
  | Unsigned => Eunop Osingleofintu e
  end.

Definition make_intoffloat (e: expr) (sg: signedness) :=
  match sg with
  | Signed => Eunop Ointoffloat e
  | Unsigned => Eunop Ointuoffloat e
  end.

Definition make_intofsingle (e: expr) (sg: signedness) :=
  match sg with
  | Signed => Eunop Ointofsingle e
  | Unsigned => Eunop Ointuofsingle e
  end.

Definition make_longofint (e: expr) (sg: signedness) :=
  match sg with
  | Signed => Eunop Olongofint e
  | Unsigned => Eunop Olongofintu e
  end.

Definition make_floatoflong (e: expr) (sg: signedness) :=
  match sg with
  | Signed => Eunop Ofloatoflong e
  | Unsigned => Eunop Ofloatoflongu e
  end.

Definition make_singleoflong (e: expr) (sg: signedness) :=
  match sg with
  | Signed => Eunop Osingleoflong e
  | Unsigned => Eunop Osingleoflongu e
  end.

Definition make_longoffloat (e: expr) (sg: signedness) :=
  match sg with
  | Signed => Eunop Olongoffloat e
  | Unsigned => Eunop Olonguoffloat e
  end.

Definition make_longofsingle (e: expr) (sg: signedness) :=
  match sg with
  | Signed => Eunop Olongofsingle e
  | Unsigned => Eunop Olonguofsingle e
  end.

Definition make_cmpu_ne_zero (e: expr) :=
  match e with
  | Ebinop (Ocmp c) e1 e2 => e
  | Ebinop (Ocmpu c) e1 e2 => e
  | Ebinop (Ocmpf c) e1 e2 => e
  | Ebinop (Ocmpfs c) e1 e2 => e
  | Ebinop (Ocmpl c) e1 e2 => e
  | Ebinop (Ocmplu c) e1 e2 => e
  | _ => Ebinop (Ocmpu Cne) e (make_intconst Int.zero)
  end.


Definition sizeof (ce: composite_env) (t: type) : res Z :=
  if complete_type ce t
  then OK (Ctypes.sizeof ce t)
  else Error (msg "incomplete type").

Definition alignof (ce: composite_env) (t: type) : res Z :=
  if complete_type ce t
  then OK (Ctypes.alignof ce t)
  else Error (msg "incomplete type").


Definition make_cast_int (e: expr) (sz: intsize) (si: signedness) :=
  match sz, si with
  | I8, Signed => Eunop Ocast8signed e
  | I8, Unsigned => Eunop Ocast8unsigned e
  | I16, Signed => Eunop Ocast16signed e
  | I16, Unsigned => Eunop Ocast16unsigned e
  | I32, _ => e
  | IBool, _ => make_cmpu_ne_zero e
  end.

Definition make_cast (from to: type) (e: expr) :=
  match classify_cast from to with
  | cast_case_pointer => OK e
  | cast_case_i2i sz2 si2 => OK (make_cast_int e sz2 si2)
  | cast_case_f2f => OK e
  | cast_case_s2s => OK e
  | cast_case_f2s => OK (make_singleoffloat e)
  | cast_case_s2f => OK (make_floatofsingle e)
  | cast_case_i2f si1 => OK (make_floatofint e si1)
  | cast_case_i2s si1 => OK (make_singleofint e si1)
  | cast_case_f2i sz2 si2 => OK (make_cast_int (make_intoffloat e si2) sz2 si2)
  | cast_case_s2i sz2 si2 => OK (make_cast_int (make_intofsingle e si2) sz2 si2)
  | cast_case_l2l => OK e
  | cast_case_i2l si1 => OK (make_longofint e si1)
  | cast_case_l2i sz2 si2 => OK (make_cast_int (Eunop Ointoflong e) sz2 si2)
  | cast_case_l2f si1 => OK (make_floatoflong e si1)
  | cast_case_l2s si1 => OK (make_singleoflong e si1)
  | cast_case_f2l si2 => OK (make_longoffloat e si2)
  | cast_case_s2l si2 => OK (make_longofsingle e si2)
  | cast_case_i2bool => OK (make_cmpu_ne_zero e)
  | cast_case_f2bool => OK (Ebinop (Ocmpf Cne) e (make_floatconst Float.zero))
  | cast_case_s2bool => OK (Ebinop (Ocmpfs Cne) e (make_singleconst Float32.zero))
  | cast_case_l2bool => OK (Ebinop (Ocmplu Cne) e (make_longconst Int64.zero))
  | cast_case_struct id1 id2 => OK e
  | cast_case_union id1 id2 => OK e
  | cast_case_void => OK e
  | cast_case_default => Error (msg "Cshmgen.make_cast")
  end.


Definition make_boolean (e: expr) (ty: type) :=
  match classify_bool ty with
  | bool_case_i => make_cmpu_ne_zero e
  | bool_case_f => Ebinop (Ocmpf Cne) e (make_floatconst Float.zero)
  | bool_case_s => Ebinop (Ocmpfs Cne) e (make_singleconst Float32.zero)
  | bool_case_l => Ebinop (Ocmplu Cne) e (make_longconst Int64.zero)
  | bool_default => e (* should not happen *)
  end.


Definition make_notbool (e: expr) (ty: type) :=
  match classify_bool ty with
  | bool_case_i => OK (Ebinop (Ocmpu Ceq) e (make_intconst Int.zero))
  | bool_case_f => OK (Ebinop (Ocmpf Ceq) e (make_floatconst Float.zero))
  | bool_case_s => OK (Ebinop (Ocmpfs Ceq) e (make_singleconst Float32.zero))
  | bool_case_l => OK (Ebinop (Ocmplu Ceq) e (make_longconst Int64.zero))
  | bool_default => Error (msg "Cshmgen.make_notbool")
  end.

Definition make_neg (e: expr) (ty: type) :=
  match classify_neg ty with
  | neg_case_i _ => OK (Eunop Onegint e)
  | neg_case_f => OK (Eunop Onegf e)
  | neg_case_s => OK (Eunop Onegfs e)
  | neg_case_l _ => OK (Eunop Onegl e)
  | neg_default => Error (msg "Cshmgen.make_neg")
  end.

Definition make_absfloat (e: expr) (ty: type) :=
  match classify_neg ty with
  | neg_case_i sg => OK (Eunop Oabsf (make_floatofint e sg))
  | neg_case_f => OK (Eunop Oabsf e)
  | neg_case_s => OK (Eunop Oabsf (make_floatofsingle e))
  | neg_case_l sg => OK (Eunop Oabsf (make_floatoflong e sg))
  | neg_default => Error (msg "Cshmgen.make_absfloat")
  end.

Definition make_notint (e: expr) (ty: type) :=
  match classify_notint ty with
  | notint_case_i _ => OK (Eunop Onotint e)
  | notint_case_l _ => OK (Eunop Onotl e)
  | notint_default => Error (msg "Cshmgen.make_notint")
  end.


Definition make_binarith (iop iopu fop sop lop lopu: binary_operation)
                         (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  let c := classify_binarith ty1 ty2 in
  let ty := binarith_type c in
  do e1' <- make_cast ty1 ty e1;
  do e2' <- make_cast ty2 ty e2;
  match c with
  | bin_case_i Signed => OK (Ebinop iop e1' e2')
  | bin_case_i Unsigned => OK (Ebinop iopu e1' e2')
  | bin_case_f => OK (Ebinop fop e1' e2')
  | bin_case_s => OK (Ebinop sop e1' e2')
  | bin_case_l Signed => OK (Ebinop lop e1' e2')
  | bin_case_l Unsigned => OK (Ebinop lopu e1' e2')
  | bin_default => Error (msg "Cshmgen.make_binarith")
  end.

Definition make_add_ptr_int (ce: composite_env) (ty: type) (si: signedness) (e1 e2: expr) :=
  do sz <- sizeof ce ty;
  if Archi.ptr64 then
    let n := make_longconst (Int64.repr sz) in
    OK (Ebinop Oaddl e1 (Ebinop Omull n (make_longofint e2 si)))
  else
    let n := make_intconst (Int.repr sz) in
    OK (Ebinop Oadd e1 (Ebinop Omul n e2)).

Definition make_add_ptr_long (ce: composite_env) (ty: type) (e1 e2: expr) :=
  do sz <- sizeof ce ty;
  if Archi.ptr64 then
    let n := make_longconst (Int64.repr sz) in
    OK (Ebinop Oaddl e1 (Ebinop Omull n e2))
  else
    let n := make_intconst (Int.repr sz) in
    OK (Ebinop Oadd e1 (Ebinop Omul n (Eunop Ointoflong e2))).

Definition make_add (ce: composite_env) (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  match classify_add ty1 ty2 with
  | add_case_pi ty si => make_add_ptr_int ce ty si e1 e2
  | add_case_pl ty => make_add_ptr_long ce ty e1 e2
  | add_case_ip si ty => make_add_ptr_int ce ty si e2 e1
  | add_case_lp ty => make_add_ptr_long ce ty e2 e1
  | add_default => make_binarith Oadd Oadd Oaddf Oaddfs Oaddl Oaddl e1 ty1 e2 ty2
  end.

Definition make_sub (ce: composite_env) (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  match classify_sub ty1 ty2 with
  | sub_case_pi ty si =>
      do sz <- sizeof ce ty;
      if Archi.ptr64 then
        let n := make_longconst (Int64.repr sz) in
        OK (Ebinop Osubl e1 (Ebinop Omull n (make_longofint e2 si)))
      else
        let n := make_intconst (Int.repr sz) in
        OK (Ebinop Osub e1 (Ebinop Omul n e2))
  | sub_case_pp ty =>
      do sz <- sizeof ce ty;
      if Archi.ptr64 then
        let n := make_longconst (Int64.repr sz) in
        OK (Ebinop Odivl (Ebinop Osubl e1 e2) n)
      else
        let n := make_intconst (Int.repr sz) in
        OK (Ebinop Odiv (Ebinop Osub e1 e2) n)
  | sub_case_pl ty =>
      do sz <- sizeof ce ty;
      if Archi.ptr64 then
        let n := make_longconst (Int64.repr sz) in
        OK (Ebinop Osubl e1 (Ebinop Omull n e2))
      else
        let n := make_intconst (Int.repr sz) in
        OK (Ebinop Osub e1 (Ebinop Omul n (Eunop Ointoflong e2)))
  | sub_default =>
      make_binarith Osub Osub Osubf Osubfs Osubl Osubl e1 ty1 e2 ty2
  end.

Definition make_mul (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  make_binarith Omul Omul Omulf Omulfs Omull Omull e1 ty1 e2 ty2.

Definition make_div (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  make_binarith Odiv Odivu Odivf Odivfs Odivl Odivlu e1 ty1 e2 ty2.

Definition make_binarith_int (iop iopu lop lopu: binary_operation)
                             (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  let c := classify_binarith ty1 ty2 in
  let ty := binarith_type c in
  do e1' <- make_cast ty1 ty e1;
  do e2' <- make_cast ty2 ty e2;
  match c with
  | bin_case_i Signed => OK (Ebinop iop e1' e2')
  | bin_case_i Unsigned => OK (Ebinop iopu e1' e2')
  | bin_case_l Signed => OK (Ebinop lop e1' e2')
  | bin_case_l Unsigned => OK (Ebinop lopu e1' e2')
  | bin_case_f | bin_case_s | bin_default => Error (msg "Cshmgen.make_binarith_int")
  end.

Definition make_mod (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  make_binarith_int Omod Omodu Omodl Omodlu e1 ty1 e2 ty2.

Definition make_and (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  make_binarith_int Oand Oand Oandl Oandl e1 ty1 e2 ty2.

Definition make_or (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  make_binarith_int Oor Oor Oorl Oorl e1 ty1 e2 ty2.

Definition make_xor (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  make_binarith_int Oxor Oxor Oxorl Oxorl e1 ty1 e2 ty2.

Definition make_shl (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  match classify_shift ty1 ty2 with
  | shift_case_ii _ => OK (Ebinop Oshl e1 e2)
  | shift_case_li _ => OK (Ebinop Oshll e1 e2)
  | shift_case_il _ => OK (Ebinop Oshl e1 (Eunop Ointoflong e2))
  | shift_case_ll _ => OK (Ebinop Oshll e1 (Eunop Ointoflong e2))
  | shift_default => Error (msg "Cshmgen.make_shl")
  end.

Definition make_shr (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  match classify_shift ty1 ty2 with
  | shift_case_ii Signed => OK (Ebinop Oshr e1 e2)
  | shift_case_ii Unsigned => OK (Ebinop Oshru e1 e2)
  | shift_case_li Signed => OK (Ebinop Oshrl e1 e2)
  | shift_case_li Unsigned => OK (Ebinop Oshrlu e1 e2)
  | shift_case_il Signed => OK (Ebinop Oshr e1 (Eunop Ointoflong e2))
  | shift_case_il Unsigned => OK (Ebinop Oshru e1 (Eunop Ointoflong e2))
  | shift_case_ll Signed => OK (Ebinop Oshrl e1 (Eunop Ointoflong e2))
  | shift_case_ll Unsigned => OK (Ebinop Oshrlu e1 (Eunop Ointoflong e2))
  | shift_default => Error (msg "Cshmgen.make_shr")
  end.

Definition make_cmp_ptr (c: comparison) (e1 e2: expr) :=
  Ebinop (if Archi.ptr64 then Ocmplu c else Ocmpu c) e1 e2.

Definition make_cmp (c: comparison) (e1: expr) (ty1: type) (e2: expr) (ty2: type) :=
  match classify_cmp ty1 ty2 with
  | cmp_case_pp => OK (make_cmp_ptr c e1 e2)
  | cmp_case_pi si =>
      OK (make_cmp_ptr c e1 (if Archi.ptr64 then make_longofint e2 si else e2))
  | cmp_case_ip si =>
      OK (make_cmp_ptr c (if Archi.ptr64 then make_longofint e1 si else e1) e2)
  | cmp_case_pl =>
      OK (make_cmp_ptr c e1 (if Archi.ptr64 then e2 else Eunop Ointoflong e2))
  | cmp_case_lp =>
      OK (make_cmp_ptr c (if Archi.ptr64 then e1 else Eunop Ointoflong e1) e2)
  | cmp_default =>
      make_binarith
        (Ocmp c) (Ocmpu c) (Ocmpf c) (Ocmpfs c) (Ocmpl c) (Ocmplu c)
        e1 ty1 e2 ty2
  end.


Definition make_extract_bitfield (sz: intsize) (sg: signedness) (pos width: Z)
                                 (addr: expr) : res expr :=
  if zle 0 pos && zlt 0 width && zle (pos + width) (bitsize_carrier sz) then
    let amount1 := Int.repr (Int.zwordsize - first_bit sz pos width - width) in
    let amount2 := Int.repr (Int.zwordsize - width) in
    let e1 := Eload (chunk_for_carrier sz) addr in
    let e2 := Ebinop Oshl e1 (make_intconst amount1) in
    let e3 := Ebinop (if intsize_eq sz IBool
                      || signedness_eq sg Unsigned then Oshru else Oshr)
                     e2 (make_intconst amount2) in
    OK e3
  else
    Error(msg "Cshmgen.extract_bitfield").


Definition make_load (addr: expr) (ty_res: type) (bf: bitfield) :=
  match bf with
  | Full =>
      match access_mode ty_res with
      | By_value chunk => OK (Eload chunk addr)
      | By_reference => OK addr
      | By_copy => OK addr
      | By_nothing => Error (msg "Cshmgen.make_load")
      end
  | Bits sz sg pos width =>
      make_extract_bitfield sz sg pos width addr
  end.


Definition make_store_bitfield (sz: intsize) (sg: signedness) (pos width: Z)
                               (addr val: expr) : res stmt :=
  if zle 0 pos && zlt 0 width && zle (pos + width) (bitsize_carrier sz) then
    let amount := first_bit sz pos width in
    let mask := Int.shl (Int.repr (two_p width - 1)) (Int.repr amount) in
    let e1 := Eload (chunk_for_carrier sz) addr in
    let e2 := Ebinop Oshl val (make_intconst (Int.repr amount)) in
    let e3 := Ebinop Oor (Ebinop Oand e2 (make_intconst mask))
                         (Ebinop Oand e1 (make_intconst (Int.not mask))) in
    OK (Sstore (chunk_for_carrier sz) addr e3)
  else
    Error(msg "Cshmgen.make_store_bitfield").


Definition make_memcpy (ce: composite_env) (dst src: expr) (ty: type) :=
  do sz <- sizeof ce ty;
  OK (Sbuiltin None (EF_memcpy sz (Ctypes.alignof_blockcopy ce ty))
                    (dst :: src :: nil)).


Definition make_store (ce: composite_env) (addr: expr) (ty: type) (bf: bitfield) (rhs: expr) :=
  match bf with
  | Full =>
      match access_mode ty with
      | By_value chunk => OK (Sstore chunk addr rhs)
      | By_copy => make_memcpy ce addr rhs ty
      | _ => Error (msg "Cshmgen.make_store")
      end
  | Bits sz sg pos width =>
      make_store_bitfield sz sg pos width addr rhs
  end.

Translation of operators

Definition transl_unop (op: Cop.unary_operation) (a: expr) (ta: type) : res expr :=
  match op with
  | Cop.Onotbool => make_notbool a ta
  | Cop.Onotint => make_notint a ta
  | Cop.Oneg => make_neg a ta
  | Cop.Oabsfloat => make_absfloat a ta
  end.

Definition transl_binop (ce: composite_env)
                        (op: Cop.binary_operation)
                        (a: expr) (ta: type)
                        (b: expr) (tb: type) : res expr :=
  match op with
  | Cop.Oadd => make_add ce a ta b tb
  | Cop.Osub => make_sub ce a ta b tb
  | Cop.Omul => make_mul a ta b tb
  | Cop.Odiv => make_div a ta b tb
  | Cop.Omod => make_mod a ta b tb
  | Cop.Oand => make_and a ta b tb
  | Cop.Oor => make_or a ta b tb
  | Cop.Oxor => make_xor a ta b tb
  | Cop.Oshl => make_shl a ta b tb
  | Cop.Oshr => make_shr a ta b tb
  | Cop.Oeq => make_cmp Ceq a ta b tb
  | Cop.One => make_cmp Cne a ta b tb
  | Cop.Olt => make_cmp Clt a ta b tb
  | Cop.Ogt => make_cmp Cgt a ta b tb
  | Cop.Ole => make_cmp Cle a ta b tb
  | Cop.Oge => make_cmp Cge a ta b tb
  end.

Translation of field accesses

Definition make_field_access (ce: composite_env) (ty: type) (f: ident) (a: expr) : res (expr * bitfield) :=
  do (ofs, bf) <-
    match ty with
    | Tstruct id _ =>
        match ce!id with
        | None => Error (MSG "Undefined struct " :: CTX id :: nil)
        | Some co => field_offset ce f (co_members co)
        end
    | Tunion id _ =>
        match ce!id with
        | None => Error (MSG "Undefined union " :: CTX id :: nil)
        | Some co => union_field_offset ce f (co_members co)
        end
    | _ =>
        Error(msg "Cshmgen.make_field_access")
    end;
  let a' :=
    if Archi.ptr64
    then Ebinop Oaddl a (make_longconst (Int64.repr ofs))
    else Ebinop Oadd a (make_intconst (Int.repr ofs)) in
  OK (a', bf).

Translation of expressions

Fixpoint transl_expr (ce: composite_env) (a: Clight.expr) {struct a} : res expr :=
  match a with
  | Clight.Econst_int n _ =>
      OK(make_intconst n)
  | Clight.Econst_float n _ =>
      OK(make_floatconst n)
  | Clight.Econst_single n _ =>
      OK(make_singleconst n)
  | Clight.Econst_long n _ =>
      OK(make_longconst n)
  | Clight.Evar id ty =>
      make_load (Eaddrof id) ty Full
  | Clight.Etempvar id ty =>
      OK(Evar id)
  | Clight.Ederef b ty =>
      do tb <- transl_expr ce b;
      make_load tb ty Full
  | Clight.Eaddrof b _ =>
      do (tb, bf) <- transl_lvalue ce b;
      match bf with
      | Full => OK tb
      | Bits _ _ _ _ => Error (msg "Cshmgen.transl_expr: addrof bitfield")
      end
  | Clight.Eunop op b _ =>
      do tb <- transl_expr ce b;
      transl_unop op tb (typeof b)
  | Clight.Ebinop op b c _ =>
      do tb <- transl_expr ce b;
      do tc <- transl_expr ce c;
      transl_binop ce op tb (typeof b) tc (typeof c)
  | Clight.Ecast b ty =>
      do tb <- transl_expr ce b;
      make_cast (typeof b) ty tb
  | Clight.Efield b i ty =>
      do tb <- transl_expr ce b;
      do (addr, bf) <- make_field_access ce (typeof b) i tb;
      make_load addr ty bf
  | Clight.Esizeof ty' ty =>
      do sz <- sizeof ce ty'; OK(make_ptrofsconst sz)
  | Clight.Ealignof ty' ty =>
      do al <- alignof ce ty'; OK(make_ptrofsconst al)
  end


with transl_lvalue (ce: composite_env) (a: Clight.expr) {struct a} : res (expr * bitfield) :=
  match a with
  | Clight.Evar id _ =>
      OK (Eaddrof id, Full)
  | Clight.Ederef b _ =>
      do tb <- transl_expr ce b; OK (tb, Full)
  | Clight.Efield b i ty =>
      do tb <- transl_expr ce b;
      make_field_access ce (typeof b) i tb
  | _ =>
      Error(msg "Cshmgen.transl_lvalue")
  end.


Fixpoint transl_arglist (ce: composite_env) (al: list Clight.expr) (tyl: typelist)
                         {struct al}: res (list expr) :=
  match al, tyl with
  | nil, Tnil => OK nil
  | a1 :: a2, Tcons ty1 ty2 =>
      do ta1 <- transl_expr ce a1;
      do ta1' <- make_cast (typeof a1) ty1 ta1;
      do ta2 <- transl_arglist ce a2 ty2;
      OK (ta1' :: ta2)
  | a1 :: a2, Tnil =>
      do ta1 <- transl_expr ce a1;
      do ta1' <- make_cast (typeof a1) (default_argument_conversion (typeof a1)) ta1;
      do ta2 <- transl_arglist ce a2 Tnil;
      OK (ta1' :: ta2)
  | _, _ =>
      Error(msg "Cshmgen.transl_arglist: arity mismatch")
  end.


Fixpoint typlist_of_arglist (al: list Clight.expr) (tyl: typelist)
                            {struct al}: list AST.typ :=
  match al, tyl with
  | nil, _ => nil
  | a1 :: a2, Tcons ty1 ty2 =>
      typ_of_type ty1 :: typlist_of_arglist a2 ty2
  | a1 :: a2, Tnil =>
      typ_of_type (default_argument_conversion (typeof a1)) :: typlist_of_arglist a2 Tnil
  end.


Definition make_normalization (t: type) (a: expr) :=
  match t with
  | Tint IBool _ _ => Eunop Ocast8unsigned a
  | Tint I8 Signed _ => Eunop Ocast8signed a
  | Tint I8 Unsigned _ => Eunop Ocast8unsigned a
  | Tint I16 Signed _ => Eunop Ocast16signed a
  | Tint I16 Unsigned _ => Eunop Ocast16unsigned a
  | _ => a
  end.

Definition make_funcall (x: option ident) (tres: type) (sg: signature)
                      (fn: expr) (args: list expr): stmt :=
  match x, return_value_needs_normalization sg.(sig_res) with
  | Some id, true =>
      Sseq (Scall x sg fn args)
           (Sset id (make_normalization tres (Evar id)))
  | _, _ =>
      Scall x sg fn args
  end.

Translation of statements