[Linux-kernel-mentees] [PATCH v4 1/3] parsing_c: Align C AST and Cocci AST for pointer
Julia Lawall
julia.lawall at inria.fr
Sun Feb 9 16:46:36 UTC 2020
On Sun, 9 Feb 2020, Jaskaran Singh wrote:
> For a pointer, the C parser constructed an AST dissimilar from that
> of the Cocci AST. This caused failures in matching with certain
> pointer types. For example, for the following case:
>
> char *1 const *2 id;
>
> The C AST constructed would be:
> const Pointer1 -> Pointer2 -> char
>
> The Cocci AST constructed would be:
> Pointer2 -> const Pointer1 -> char
>
> Change the pointer rule in the C parser so that an AST similar to the
> Cocci AST is constructed.
>
> Make necessary changes in the C pretty printer so that the pointer type
> is printed correctly.
>
> Signed-off-by: Jaskaran Singh <jaskaransingh7654321 at gmail.com>
> ---
> parsing_c/parser_c.mly | 4 ++--
> parsing_c/pretty_print_c.ml | 14 ++++++++++----
> 2 files changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/parsing_c/parser_c.mly b/parsing_c/parser_c.mly
> index 8d7b761e..4c74f15a 100644
> --- a/parsing_c/parser_c.mly
> +++ b/parsing_c/parser_c.mly
> @@ -1333,14 +1333,14 @@ pointer:
> | tmul { (Ast_c.noattr,fun x -> mk_ty (Pointer x) [$1]) }
> | tmul pointer
> { let (attr,ptr) = $2 in
> - (attr,fun x -> mk_ty (Pointer (ptr x)) [$1]) }
> + (attr,fun x -> ptr (mk_ty (Pointer x) [$1])) }
> | tmul type_qualif_list
> { let (attr,tq) = $2 in
> (attr,fun x -> (tq.qualifD, mk_tybis (Pointer x) [$1]))}
> | tmul type_qualif_list pointer
> { let (attr1,tq) = $2 in
> let (attr2,ptr) = $3 in
> - (attr1 at attr2,fun x -> (tq.qualifD, mk_tybis (Pointer (ptr x)) [$1])) }
> + (attr1 at attr2,fun x -> ptr (tq.qualifD, mk_tybis (Pointer x) [$1])) }
>
> tmul:
> TMul { $1 }
> diff --git a/parsing_c/pretty_print_c.ml b/parsing_c/pretty_print_c.ml
> index a2e35588..3aaa97ca 100644
> --- a/parsing_c/pretty_print_c.ml
> +++ b/parsing_c/pretty_print_c.ml
> @@ -804,11 +804,14 @@ and pp_string_format (e,ii) =
> (FunctionType (return=void, params=int i) *)
> (*WRONG I THINK, use left & right function *)
> (* bug: pp_type_with_ident_rest None t; print_ident ident *)
> + pp_type_left t;
> pr_elem i;
> - iiqu +> List.iter pr_elem; (* le const est forcement apres le '*' *)
> + iiqu +>
> + List.iter (* le const est forcement apres le '*' *)
> + (function x -> (pr_space(); pr_elem x));
There is no need for the parentheses around the pr_space and pr_elem
calls.
> if iiqu <> [] || get_comments_after i <> []
> then pr_space();
> - pp_type_with_ident_rest ident t attrs Ast_c.noattr;
> + print_ident ident
>
> (* ugly special case ... todo? maybe sufficient in practice *)
> | (ParenType ttop, [i1;i2]) ->
> @@ -885,11 +888,14 @@ and pp_string_format (e,ii) =
> match ty, iity with
> (NoType,_) -> failwith "pp_type_left: unexpected NoType"
> | (Pointer t, [i]) ->
> + pp_type_left t;
> pr_elem i;
> - iiqu +> List.iter pr_elem; (* le const est forcement apres le '*' *)
> + iiqu +>
> + List.iter (* le const est forcement apres le '*' *)
> + (function x -> (pr_space(); pr_elem x));
> if iiqu <> [] || get_comments_after i <> []
> then pr_space();
> - pp_type_left t
> + ()
This is not needed. YOu can just drop the ; after the pr_space() and the
whole call to pp_type_left.
julia
>
> | (Array (eopt, t), [i1;i2]) -> pp_type_left t
> | (FunctionType (returnt, paramst), [i1;i2]) -> pp_type_left returnt
> --
> 2.21.1
>
>
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