[Linux-kernel-mentees] [PATCH 01/26] parsing_cocci: Add Function Prototype token
Jaskaran Singh
jaskaransingh7654321 at gmail.com
Thu Mar 19 13:58:53 UTC 2020
On Wed, 2020-03-18 at 18:25 +0100, Julia Lawall wrote:
>
> On Mon, 16 Mar 2020, Jaskaran Singh wrote:
>
> > To add the types ParenType and FunctionType to the SmPL AST, a
> > reduce/reduce conflict with the funproto rule of the SmPL parser
> > must be resolved. This requires explicitly identifying a function
> > prototype by use of a token (TFunProto).
> >
> > While the correct method of identifying a function prototype would
> > be to
> > check if an identifier is preceded by a return type, it is
> > challenging
> > to implement. This is because implementing an OCaml function, to
> > correctly determine a C type in SmPL, without the aid of Yacc,
> > would
> > have to handle a number of cases (disjunctions, typeof expressions,
> > etc.).
> >
> > Thus, a slightly hacky approach is taken to determine a function
> > prototype with not the best certainty but what works for most cases
> > in SmPL. If the identifier is preceded by any token that does not
> > seem to be part of a type, then it is not identified as a function
> > prototype. Else, it is.
>
> This sacrifices the test case tests/p1p2.cocci:
>
What do you mean by sacrifice?
The test case seems to work, but not with just 01 applied. Here's what
the debugger tells me about the AST:
Ast_cocci.FunProto
([Ast_cocci.FType
{Ast_cocci.node =
Ast_cocci.Type (false, None,
{Ast_cocci.node =
Ast_cocci.MetaType
((("rule starting on line 11", "T"),
{Ast_cocci.line = 18; column = 1;
strbef = []; straft = [];
whitespace = " "},
Ast_cocci.CONTEXT (Ast_cocci.NoPos,
Ast_cocci.AFTER
([[Ast_cocci.Directive
[Ast_cocci.Space
"__attribute__((nonnull(2)))"]]],
Ast_cocci.ONE)),
[]),
Maybe after the grammar changes, Menhir does some kind of lookahead?
I'm not sure.
Cheers,
Jaskaran.
> @@
> typedef Error;
> type T;
> identifier FN;
> parameter P1;
> @@
> T
> +__attribute__((nonnull(1)))
> FN(P1, Error **errp);
>
> @@
> typedef Error;
> type T;
> identifier FN;
> parameter P1;
> parameter P2;
> @@
> T
> +__attribute__((nonnull(2)))
> FN(P1, P2, Error **errp);
>
> Normally, the only way that you can have a ) before a function call
> is
> when there is a cast. But hopefully in that case there would not be
> two
> )) before the function call. Can that get around the problem?
>
> julia
>
>
>
>
> > Signed-off-by: Jaskaran Singh <jaskaransingh7654321 at gmail.com>
> > ---
> > parsing_cocci/parse_cocci.ml | 72
> > +++++++++++++++++++++++----
> > parsing_cocci/parser_cocci_menhir.mly | 9 ++--
> > 2 files changed, 67 insertions(+), 14 deletions(-)
> >
> > diff --git a/parsing_cocci/parse_cocci.ml
> > b/parsing_cocci/parse_cocci.ml
> > index 679d213a..4b2cb7e4 100644
> > --- a/parsing_cocci/parse_cocci.ml
> > +++ b/parsing_cocci/parse_cocci.ml
> > @@ -295,6 +295,7 @@ let token2c (tok,_) add_clt =
> > | PC.TLineEnd(clt) -> "line end"
> > | PC.TInvalid -> "invalid"
> > | PC.TFunDecl(clt) -> "fundecl"
> > + | PC.TFunProto(clt) -> "funproto"
> >
> > | PC.TIso -> "<=>"
> > | PC.TRightIso -> "=>"
> > @@ -480,7 +481,7 @@ let get_clt (tok,_) =
> >
> > | PC.TOPar0(_,clt) | PC.TMid0(_,clt) | PC.TAnd0(_,clt) |
> > PC.TCPar0(_,clt)
> > | PC.TOEllipsis(clt) | PC.TCEllipsis(clt)
> > - | PC.TPOEllipsis(clt) | PC.TPCEllipsis(clt)
> > + | PC.TPOEllipsis(clt) | PC.TPCEllipsis(clt) | PC.TFunProto(clt)
> > | PC.TFunDecl(clt) | PC.TDirective(_,clt) | PC.TAttr_(clt)
> > | PC.TLineEnd(clt) -> clt
> > | PC.TVAEllipsis(clt) -> clt
> > @@ -718,6 +719,7 @@ let update_clt (tok,x) clt =
> >
> > | PC.TLineEnd(_) -> (PC.TLineEnd(clt),x)
> > | PC.TFunDecl(_) -> (PC.TFunDecl(clt),x)
> > + | PC.TFunProto(_) -> (PC.TFunProto(clt),x)
> > | PC.TTildeExclEq(_) -> (PC.TTildeExclEq(clt),x)
> > | PC.TDirective(a,_) -> (PC.TDirective(a,clt),x)
> > | PC.TAttr_(_) -> (PC.TAttr_(clt),x)
> > @@ -925,7 +927,7 @@ let split_token ((tok,_) as t) =
> > | PC.TInitialize | PC.TFinalize -> ([t],[t])
> > | PC.TPArob clt | PC.TMetaPos(_,_,_,clt) | PC.TMetaCom(_,_,clt)
> > -> split t clt
> >
> > - | PC.TFunDecl(clt)
> > + | PC.TFunDecl(clt) | PC.TFunProto(clt)
> > | PC.TWhen(clt) | PC.TWhenTrue(clt) | PC.TWhenFalse(clt)
> > | PC.TAny(clt) | PC.TStrict(clt) | PC.TLineEnd(clt)
> > | PC.TEllipsis(clt)
> > @@ -1006,7 +1008,8 @@ let find_function_names l =
> > | _ -> false in
> > let rec split acc = function
> > [] | [_] -> raise Irrelevant
> > - | ((PC.TCPar(_),_) as t1) :: ((PC.TOBrace(_),_) as t2) :: rest
> > ->
> > + | ((PC.TCPar(_),_) as t1) :: ((PC.TOBrace(_),_) as t2) :: rest
> > + | ((PC.TCPar(_),_) as t1) :: ((PC.TPtVirg(_),_) as t2) :: rest
> > ->
> > (List.rev (t1::acc),(t2::rest))
> > | x::xs -> split (x::acc) xs in
> > let rec balanced_name level = function
> > @@ -1037,7 +1040,48 @@ let find_function_names l =
> > | (PC.TArobArob,_)::_ | (PC.TArob,_)::_ | (PC.EOF,_)::_ ->
> > raise Irrelevant
> > | t::rest -> balanced_args level rest in
> > - let rec loop = function
> > + let rec is_permissible_proto = function
> > + [] -> false
> > + | (PC.TCPar0(_),_)::
> > + ((PC.TMid0(_),_) | (PC.TAnd0(_),_))::
> > + (PC.TOPar0(_),_)::_ -> false
> > + | (PC.TOPar0(_),_)::rest
> > + | (PC.TCPar0(_),_)::rest -> is_permissible_proto rest
> > + | x::rest when is_mid x ->
> > + let rec loop = function
> > + [] -> false
> > + | (PC.TOPar0(_),_)::xs -> is_permissible_proto xs
> > + | x::xs -> loop xs in
> > + loop rest
> > + | _::((PC.TEq(_),_) | (PC.TNotEq(_),_))::(PC.TWhen(_),_)::_
> > + | _::(PC.TWhen(_),_)::_
> > + | (PC.TComma(_),_)::_
> > + | (PC.TDirective(_),_)::_
> > + | (PC.TElse(_),_)::_
> > + | (PC.TReturn(_),_)::_
> > + | (PC.TMetaStm(_),_)::_
> > + | (PC.TMetaExp(_),_)::_
> > + | (PC.TMetaId(_),_)::_
> > + | (PC.TMetaLocalIdExp(_),_)::_
> > + | (PC.TEq(_),_)::_
> > + | (PC.TEllipsis(_),_)::_
> > + | (PC.TOEllipsis(_),_)::_
> > + | (PC.TCEllipsis(_),_)::_
> > + | (PC.TPOEllipsis(_),_)::_
> > + | (PC.TPCEllipsis(_),_)::_
> > + | (PC.TPtVirg(_),_)::_
> > + | (PC.TOBrace(_),_)::_
> > + | (PC.TCBrace(_),_)::_
> > + | (PC.TOPar(_),_)::_
> > + | (PC.TCPar(_),_)::_
> > + | (PC.TIdent(_),_)::_ -> false
> > + | _ -> true in
> > + let decl_or_proto clt info bef aft =
> > + match aft with
> > + (PC.TOBrace(_),_)::_ -> (((PC.TFunDecl(clt),info) :: bef),
> > aft)
> > + | (PC.TPtVirg(_),_)::_ -> (((PC.TFunProto(clt),info) :: bef),
> > aft)
> > + | _ -> raise Irrelevant in
> > + let rec loop acc = function
> > [] -> []
> > | t :: rest ->
> > if is_par t || is_mid t || is_ident t
> > @@ -1046,26 +1090,30 @@ let find_function_names l =
> > try
> > let (bef,aft) = split [] (t::rest) in
> > let rest = balanced_name 0 bef in
> > + (match aft with
> > + (PC.TPtVirg(_),_)::_
> > + when not(is_permissible_proto acc) -> raise
> > Irrelevant
> > + | _ ->
> > (match rest with
> > (PC.TOPar(_),_)::_ ->
> > (match balanced_args 0 rest with
> > [] ->
> > let (_,info) as h = List.hd bef in
> > let clt = get_clt h in
> > - (((PC.TFunDecl(clt),info) :: bef), aft)
> > + decl_or_proto clt info bef aft
> > | (PC.TAttr_(_),_)::rest ->
> > (match balanced_args 0 rest with
> > [] ->
> > let (_,info) as h = List.hd bef in
> > let clt = get_clt h in
> > - (((PC.TFunDecl(clt),info) :: bef), aft)
> > + decl_or_proto clt info bef aft
> > | _ -> raise Irrelevant)
> > | _ -> raise Irrelevant)
> > - | _ -> raise Irrelevant)
> > + | _ -> raise Irrelevant))
> > with Irrelevant -> ([t],rest) in
> > - t @ (loop rest)
> > - else t :: (loop rest) in
> > - loop l
> > + t @ (loop (t @ acc) rest)
> > + else t :: (loop (t :: acc) rest) in
> > + loop [] l
> >
> > (* -------------------------------------------------------------
> > ---------- *)
> > (* an attribute is an identifier that precedes another identifier
> > and
> > @@ -1168,6 +1216,8 @@ let detect_types in_meta_decls l =
> > delim::newid::id::(loop false infn (ident::type_names) rest)
> > | ((PC.TFunDecl(_),_) as fn)::rest ->
> > fn::(loop false 1 type_names rest)
> > + | ((PC.TFunProto(_),_) as fn)::rest ->
> > + fn::(loop false 1 type_names rest)
> > | ((PC.TOPar(_),_) as lp)::rest when infn > 0 ->
> > lp::(loop false (infn + 1) type_names rest)
> > | ((PC.TCPar(_),_) as rp)::rest when infn > 0 ->
> > @@ -1252,7 +1302,7 @@ let token2line (tok,_) =
> > | PC.TMetaDParamList(_,_,_,_,clt) | PC.TMetaFunc(_,_,_,clt)
> > | PC.TMetaLocalFunc(_,_,_,clt) | PC.TMetaPos(_,_,_,clt) |
> > PC.TMetaCom(_,_,clt)
> >
> > - | PC.TFunDecl(clt)
> > + | PC.TFunDecl(clt) | PC.TFunProto(clt)
> > | PC.TWhen(clt) | PC.TWhenTrue(clt) | PC.TWhenFalse(clt)
> > | PC.TAny(clt) | PC.TStrict(clt) | PC.TEllipsis(clt)
> >
> > diff --git a/parsing_cocci/parser_cocci_menhir.mly
> > b/parsing_cocci/parser_cocci_menhir.mly
> > index 9e6c8a08..26958f63 100644
> > --- a/parsing_cocci/parser_cocci_menhir.mly
> > +++ b/parsing_cocci/parser_cocci_menhir.mly
> > @@ -239,7 +239,8 @@ let inline_id aft = function
> >
> > %token <Data.clt> TVAEllipsis
> > %token <Data.clt> TIf TElse TWhile TFor TDo TSwitch TCase TDefault
> > TReturn
> > -%token <Data.clt> TBreak TContinue TGoto TSizeof TTypeof TFunDecl
> > Tdecimal Texec
> > +%token <Data.clt> TBreak TContinue TGoto TSizeof TTypeof TFunDecl
> > TFunProto
> > +%token <Data.clt> Tdecimal Texec
> > %token <string * Data.clt> TIdent TTypeId TDeclarerId TIteratorId
> > TSymId
> > %token <Ast_cocci.added_string * Data.clt> TDirective
> > %token <Data.clt> TAttr_
> > @@ -1439,7 +1440,8 @@ reverse_separated_nonempty_llist(separator,
> > X):
> >
> > funproto:
> > s=ioption(storage) i=ioption(Tinline) t=ctype
> > - id=fn_ident lp=TOPar arglist=arg_list(name_opt_decl) rp=TCPar
> > pt=TPtVirg
> > + TFunProto id=fn_ident
> > + lp=TOPar arglist=arg_list(name_opt_decl) rp=TCPar pt=TPtVirg
> > { let s = match s with None -> [] | Some s -> [Ast0.FStorage
> > s] in
> > let i =
> > match i with
> > @@ -1453,7 +1455,8 @@ funproto:
> > P.clt2mcode "(" lp, args, vararg, P.clt2mcode ")" rp,
> > P.clt2mcode ";" pt)) }
> > | i=Tinline s=storage t=ctype
> > - id=fn_ident lp=TOPar arglist=arg_list(name_opt_decl) rp=TCPar
> > pt=TPtVirg
> > + TFunProto id=fn_ident
> > + lp=TOPar arglist=arg_list(name_opt_decl) rp=TCPar pt=TPtVirg
> > { let s = [Ast0.FStorage s] in
> > let i = [Ast0.FInline (P.clt2mcode "inline" i)] in
> > let t = [Ast0.FType t] in
> > --
> > 2.21.1
> >
> >
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