Source file C_simplify.ml
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(**
C_simplify - C AST to C AST simplification
*)
open C_AST
open C_utils
let tmp_name = "__SAST_tmp"
type context = {
mutable uid: int;
target: C.target_info;
}
let create_context ?(min_uid=0) (target:C.target_info) = {
uid = min_uid;
target = target;
}
let new_uid ctx =
ctx.uid <- ctx.uid + 1;
ctx.uid
let make_temp ctx range ?(com:comment list=[]) (f:func option) (t:type_qual) : variable =
let u = new_uid ctx in
let v = {
var_uid = u;
var_org_name = tmp_name;
var_unique_name = Printf.sprintf "%s_%i" tmp_name u;
var_kind = (
match f with
| Some f -> Variable_local f
| None -> Variable_global
);
var_type = t;
var_init = None;
var_range = range;
var_com = com;
var_before_stmts = [];
var_after_stmts = [];
}
in
(match f with
| Some f -> f.func_local_vars <- v::f.func_local_vars
| None -> ());
v
let int_promote target ((e,(t,q),r) as ee) =
match t with
| T_integer i ->
if sizeof_int target i < sizeof_int target SIGNED_INT
then E_cast (ee, IMPLICIT), (T_integer SIGNED_INT,q), r
else ee
| T_bool ->
E_cast (ee, IMPLICIT), (T_integer SIGNED_INT,q), r
| _ ->
ee
let rec expr_one target range (t:typ) =
match t with
| T_integer i ->
let ii =
if sizeof_int target i < sizeof_int target SIGNED_INT then SIGNED_INT
else i
in
expr_integer_cst range ii Z.one
| T_bool ->
expr_integer_cst range SIGNED_INT Z.one
| T_float f ->
expr_float_cst range f 1.
| T_pointer _ ->
expr_integer_cst range (ptrdiff_type target) Z.one
| T_bitfield (t,_) ->
expr_one target range t
| T_enum u ->
expr_one target range (T_integer (match u.enum_integer_type with | Some s -> s | None -> assert false))
| T_typedef d ->
expr_one target range (fst d.typedef_def)
| _ ->
error range "cannot increment type" (C_print.string_of_type t)
let as_expr_stmt l t r : expr =
match l with
| [S_expression e,_] -> e
| [] -> expr_void r
| _ -> E_statement (make_block l), t, r
let scope_temp range (s:statement list) : statement list =
let b = make_block s in
if b.blk_local_vars = [] then s else [S_block b,range]
(** Simplification functions *)
let rec simplify_expr ctx f (call:bool) ((e,t,r):expr)
: (statement list) * (expr) * (statement list) =
match e with
| E_conditional (e1,e2,e3) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
if is_void t then
let cond = S_if (e1,
simplify_expr_stmt ctx f call e2 |> make_block,
simplify_expr_stmt ctx f call e3 |> make_block), r
in
before1@[cond], expr_void r, after1
else
let before2, e2, after2 = simplify_expr ctx f call e2 in
let before3, e3, after3 = simplify_expr ctx f call e3 in
let tmp = make_temp ctx r f t in
let tmp_var = E_variable tmp, t, r in
let create = S_local_declaration tmp, r in
let cond =
S_if (e1,
before2@[S_expression (E_assign (tmp_var, e2), t, r), r]@after2 |> make_block,
before3@[S_expression (E_assign (tmp_var, e3), t, r), r]@after3 |> make_block), r
in
before1@[create;cond], tmp_var, after1
| E_binary_conditional (e1,e2) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
if is_void t then
let cond = S_if (e1,
[] |> make_block,
simplify_expr_stmt ctx f call e2 |> make_block), r
in
before1@[cond], expr_void r, after1
else
let before2, e2, after2 = simplify_expr ctx f call e2 in
let tmp = make_temp ctx r f t in
let tmp_var = E_variable tmp, t, r in
let create = S_local_declaration tmp, r in
let cond =
S_if (e1,
[S_expression (E_assign (tmp_var, e1), t, r), r] |> make_block,
before2@[S_expression (E_assign (tmp_var, e2), t, r), r]@after2 |> make_block), r
in
before1@[create;cond], tmp_var, after1
| E_array_subscript(e1,e2) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let before2, e2, after2 = simplify_expr ctx f call e2 in
before1@before2, (E_array_subscript(e1,e2), t, r), after2@after1
| E_member_access (e1,i,field) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
before1, (E_member_access (e1,i,field), t, r), after1
| E_arrow_access (e1,i,field) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
before1, (E_arrow_access (e1,i,field), t, r), after1
| E_compound_assign (e1,t1,op,e2,t2) ->
let before1, e1, after1 = simplify_expr ctx f true e1 in
let before2, e2, after2 = simplify_expr ctx f call e2 in
let before = before1@before2 and after = after2@after1 in
let e1t1 = E_cast (e1, IMPLICIT), t1, r in
let e12 = E_binary (O_arithmetic op, e1t1, e2), t2, r in
let e12t = E_cast (e12, IMPLICIT), t, r in
let assign = S_expression (E_assign (e1, e12t), t, r), r in
before@[assign], e1, after
| E_binary (O_logical LOGICAL_OR, e1, e2) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let before2, e2, after2 = simplify_expr ctx f call e2 in
if before2 = [] && after2 = [] && after1 = [] then
before1, (E_binary (O_logical LOGICAL_OR, e1, e2), t, r), []
else
let tmp = make_temp ctx r f bool_type in
let tmp_var = E_variable tmp, bool_type, r in
let create = S_local_declaration tmp, r in
let e1' = match expr_type e1 |> resolve_typedef |> fst with
| T_bool -> e1
| _ -> (E_cast(e1,IMPLICIT),bool_type,r)
and e2' = match expr_type e2 |> resolve_typedef |> fst with
| T_bool -> e2
| _ -> (E_cast(e2,IMPLICIT),bool_type,r)
in
let assign1 = S_expression (E_assign (tmp_var, e1'), t, r), r in
let assign2 =
S_if (tmp_var,
[] |> make_block,
before2@[S_expression (E_assign (tmp_var, e2'), t, r), r]@after2 |> make_block), r
in
before1@[create;assign1]@after1@[assign2], tmp_var, []
| E_binary (O_logical LOGICAL_AND, e1, e2) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let before2, e2, after2 = simplify_expr ctx f call e2 in
if before2 = [] && after2 = [] && after1 = [] then
before1, (E_binary (O_logical LOGICAL_AND, e1, e2), t, r), []
else
let tmp = make_temp ctx r f bool_type in
let tmp_var = E_variable tmp, bool_type, r in
let create = S_local_declaration tmp, r in
let e1' = match expr_type e1 |> resolve_typedef |> fst with
| T_bool -> e1
| _ -> (E_cast(e1,IMPLICIT),bool_type,r)
and e2' = match expr_type e2 |> resolve_typedef |> fst with
| T_bool -> e2
| _ -> (E_cast(e2,IMPLICIT),bool_type,r)
in
let assign1 = S_expression (E_assign (tmp_var, e1'), t, r), r in
let assign2 =
S_if (tmp_var,
before2@[S_expression (E_assign (tmp_var, e2'), t, r), r]@after2 |> make_block,
[] |> make_block), r
in
before1@[create;assign1]@after1@[assign2], tmp_var, []
| E_binary (op,e1,e2) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let before2, e2, after2 = simplify_expr ctx f call e2 in
let before = before1@before2 and after = after2@after1 in
before, (E_binary (op,e1,e2), t, r), after
| E_assign (e1,e2) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let before2, e2, after2 = simplify_expr ctx f call e2 in
let before = before1@before2 and after = after2@after1 in
let assign = S_expression (E_assign (e1,e2), t, r), r in
before@[assign], e1, after
| E_comma (e1,e2) ->
let b1 = simplify_expr_stmt ctx f call e1 in
let before2, e2, after2 = simplify_expr ctx f call e2 in
b1@before2, e2, after2
| E_unary (op,e1) ->
let before1, e1, after2 = simplify_expr ctx f call e1 in
before1, (E_unary (op,e1), t, r), after2
| E_increment (dir,PRE,e1) ->
let before1, e1, after1 = simplify_expr ctx f true e1 in
let ep = int_promote ctx.target e1 in
let op = O_arithmetic (if dir = INC then ADD else SUB) in
let e1p = E_binary (op, ep, expr_one ctx.target r (fst t)), t, r in
let e1c = E_cast (e1p, IMPLICIT), t, r in
let inc = S_expression (E_assign (e1,e1c), t, r), r in
before1@[inc], e1, after1
| E_increment (dir,POST,e1) ->
let before1, e1, after1 = simplify_expr ctx f true e1 in
let ep = int_promote ctx.target e1 in
let op = O_arithmetic (if dir = INC then ADD else SUB) in
let e1p = E_binary (op, ep, expr_one ctx.target r (fst t)), t, r in
let e1c = E_cast (e1p, IMPLICIT), t, r in
let inc = S_expression (E_assign (e1,e1c), t, r), r in
before1, e1, after1@[inc]
| E_address_of e1 ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
before1, (E_address_of e1, t, r), after1
| E_deref e1 ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
before1, (E_deref e1, t, r), after1
| E_cast (e1,x) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
before1, (E_cast (e1,x), t, r), after1
| E_call (e1,ea) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let ea = Array.copy ea in
let beforea, aftera = ref before1, ref after1 in
for i=0 to Array.length ea-1 do
let before, ee, after = simplify_expr ctx f call ea.(i) in
beforea := before@(!beforea);
aftera := after@(!aftera);
ea.(i) <- ee
done;
let ecall = E_call (e1,ea), t, r in
if is_void t || not call then
!beforea, ecall, !aftera
else (
let tmp = make_temp ctx r f t in
let tmp_var = E_variable tmp, t, r in
let create = S_local_declaration tmp, r in
let bind = S_expression (E_assign (tmp_var, ecall), t, r), r in
!beforea@[create;bind], tmp_var, !aftera
)
| E_character_literal _
| E_integer_literal _
| E_float_literal _
| E_string_literal _
| E_variable _
| E_function _
| E_predefined _
-> [], (e,t,r), []
| E_var_args e1 ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
before1, (E_var_args e1, t, r), after1
| E_atomic (i,e1,e2) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let before2, e2, after2 = simplify_expr ctx f call e2 in
let before = before1@before2 and after = after2@after1 in
before, (E_atomic (i,e1,e2), t, r), after
| E_compound_literal i ->
let before1, i, after1 = simplify_init ctx f call i in
let tmp = make_temp ctx r f t in
let tmp_var = E_variable tmp, t, r in
let create = S_local_declaration tmp, r in
tmp.var_init <- Some i;
before1@[create], tmp_var, after1
| E_statement b ->
let rec doit acc = function
| [S_expression e1, r] ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let before1, e1 = remove_after ctx f before1 e1 after1 in
acc@before1, e1, []
| s::rest ->
doit (acc@(simplify_stmt ctx f call s)) rest
| [] ->
acc, expr_void r, []
in
doit [] b.blk_stmts
| E_convert_vector e1 ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
before1, (E_convert_vector e1, t, r), after1
| E_vector_element (e1,a) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
before1, (E_vector_element (e1, a), t, r), after1
| E_shuffle_vector ea ->
let ea = Array.copy ea in
let beforea, aftera = ref [], ref [] in
for i=0 to Array.length ea-1 do
let before, ee, after = simplify_expr ctx f call ea.(i) in
beforea := before@(!beforea);
aftera := after@(!aftera);
ea.(i) <- ee
done;
!beforea, (E_shuffle_vector ea, t, r), !aftera
and simplify_expr_stmt ctx f (call:bool) ((e,t,r):expr) : statement list =
match e with
| E_conditional (e1,e2,e3) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let cond = S_if (e1,
simplify_expr_stmt ctx f call e2 |> make_block,
simplify_expr_stmt ctx f call e3 |> make_block), r
in
before1@[cond]@after1
| E_binary_conditional (e1,e2) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let cond = S_if (e1,
[] |> make_block,
simplify_expr_stmt ctx f call e2 |> make_block), r
in
before1@[cond]@after1
| E_assign _ ->
let before, e, after = simplify_expr ctx f call (e,t,r) in
before@after
| E_compound_assign _
| E_increment _ ->
let before, e, after = simplify_expr ctx f call (e,t,r) in
before@after
| E_comma (e1,e2) ->
let b1 = simplify_expr_stmt ctx f call e1 in
let b2 = simplify_expr_stmt ctx f call e2 in
b1@b2
| E_call _
| E_unary _
| E_binary _
| E_array_subscript _
| E_member_access _
| E_arrow_access _
| E_address_of _
| E_deref _
| E_cast _
| E_character_literal _
| E_integer_literal _
| E_float_literal _
| E_string_literal _
| E_variable _
| E_function _
| E_predefined _
| E_var_args _
| E_atomic _
| E_compound_literal _
| E_convert_vector _
| E_vector_element _
| E_shuffle_vector _
->
let before,e,after = simplify_expr ctx f call (e,t,r) in
before@[S_expression e, r]@after
| E_statement b ->
List.concat (List.map (simplify_stmt ctx f call) b.blk_stmts)
and simplify_init ctx f (call:bool) (i:init) : (statement list) * init * (statement list) =
match i with
| I_init_expr e1 ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
before1, I_init_expr e1, after1
| I_init_list (l1,opt) ->
let before, l, after =
List.fold_left (fun (before,l,after) i ->
let before', i', after' = simplify_init ctx f call i in
before'@before, i'::l, after'@after
) ([],[],[]) l1
in
before, I_init_list (List.rev l, opt), after
| I_init_implicit _ -> [], i, []
and simplify_stmt ctx f (call:bool) ((s,r):statement) : statement list =
match s with
| S_local_declaration v ->
(match v.var_init with
| None -> [s,r]
| Some i ->
let before, i, after = simplify_init ctx f call i in
v.var_init <- Some i;
before@[s,r]@after
)
| S_expression e ->
scope_temp r (simplify_expr_stmt ctx f call e)
| S_block b ->
[S_block (simplify_block ctx f call b),r]
| S_if (e1,b1,b2) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let before1, e1 = remove_after ctx f before1 e1 after1 in
scope_temp r (before1@[S_if (e1,
simplify_block ctx f call b1,
simplify_block ctx f call b2), r])
| S_while (e1,b1) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let e1 = as_expr ctx f before1 e1 after1 in
[S_while (e1, simplify_block ctx f call b1), r]
| S_do_while (b1,e1) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let e1 = as_expr ctx f before1 e1 after1 in
[S_do_while (simplify_block ctx f call b1, e1), r]
| S_for (b1,e2,e3,b4) ->
let e2 = match e2 with
| None -> None
| Some e2 ->
let before2, e2, after2 = simplify_expr ctx f call e2 in
Some (as_expr ctx f before2 e2 after2)
and e3 = match e3 with
| None -> None
| Some ((_,t3,r3) as e3) ->
Some (as_expr_stmt (simplify_expr_stmt ctx f call e3) t3 r3)
in
[S_for (simplify_block ctx f call b1, e2, e3, simplify_block ctx f call b4), r]
| S_jump (S_return (Some e1, u)) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let before1, e1 = remove_after ctx f before1 e1 after1 in
scope_temp r (before1@[S_jump (S_return (Some e1, u)), r])
| S_jump (S_switch (e1,b1)) ->
let before1, e1, after1 = simplify_expr ctx f call e1 in
let before1, e1 = remove_after ctx f before1 e1 after1 in
scope_temp r (before1@[S_jump (S_switch (e1, simplify_block ctx f call b1)), r])
| S_jump _ | S_target _ | S_asm _ ->
[s,r]
and simplify_block ctx f (call:bool) (b:block) : block =
make_block (List.concat (List.map (simplify_stmt ctx f call) b.blk_stmts))
and remove_after ctx f before ((_,t,r) as e) after : statement list * expr =
if after = [] then before, e
else
let tmp = make_temp ctx r f t in
let tmp_var = E_variable tmp, t, r in
let create = S_local_declaration tmp, r in
let assign = S_expression (E_assign (tmp_var,e), t, r), r in
before@[create;assign]@after, tmp_var
and as_expr ctx f before ((_,t,r) as e) after : expr =
let before, e = remove_after ctx f before e after in
if before = [] then e
else E_statement (before@[S_expression e, r] |> make_block), t, r
(** Entry points *)
let simplify_func ctx (f:func) =
match f.func_body with
| Some body -> f.func_body <- Some (simplify_block ctx (Some f) false body |> resolve_scope);
| None -> ()
let simplify_global_init ctx (i:init) : (statement list) * init * (statement list) =
simplify_init ctx None false i