[Cocci] [PATCH v4 0/3] cocci: Align the C AST and Cocci AST for pointer

[Cocci] [PATCH v4 0/3] cocci: Align the C AST and Cocci AST for pointer

[Jaskaran Singh]

This series is to address the type matching problem in Coccinelle.

Patch 1/3 is for aligning the C and Cocci AST so that
pointer to const pointer and its variants can be matched.

Patch 2/3 reflects the pretty printing changes made in 
1/3 in the ptrconstptr test case. A space is added between
the * and const.

Patch 3/3 consists of a test case for matching a pointer to
const pointer and its variants.

Changes in v4:
--------------
- Change coding style w/r/t placement of comment with List.iter and
  the qualifier printing function.

Changes in v3:
--------------
- Add a space between the * and qualifier in Patch 1/3.
- Add Patch 2/3 to add a space between * and const in the test
  case ptrconstptr.

Changes in v2:
--------------
- Change body and subject of Patch 2/2 as per suggestion of Markus
  Elfring.

[PATCH v4 1/3] parsing_c: Align C AST and Cocci AST for pointer
[PATCH v4 2/3] tests: Add space between * and const in
[PATCH v4 3/3] tests: Add test case to match const pointer variants

 parsing_c/parser_c.mly      |    4 ++--
 parsing_c/pretty_print_c.ml |   14 ++++++++++----
 tests/constptr.c            |    7 +++++++
 tests/constptr.cocci        |   19 +++++++++++++++++++
 tests/constptr.res          |    7 +++++++
 tests/ptrconstptr.res       |    2 +-
 6 files changed, 46 insertions(+), 7 deletions(-)

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[Cocci] [PATCH v4 1/3] parsing_c: Align C AST and Cocci AST for pointer

[Jaskaran Singh]

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@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@attr2,fun x -> (tq.qualifD, mk_tybis (Pointer (ptr x)) [$1])) }
+       (attr1@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));
           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
+          ()
 
       | (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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[Cocci] [PATCH v4 2/3] tests: Add space between * and const in ptrconstptr.res

[Jaskaran Singh]

A space is now added between the * and qualifier. Reflect this
change in the ptrconstptr test case.

Signed-off-by: Jaskaran Singh <jaskaransingh7654321@gmail.com>
---
 tests/ptrconstptr.res | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/ptrconstptr.res b/tests/ptrconstptr.res
index f5b2210c..1d0c3c1d 100644
--- a/tests/ptrconstptr.res
+++ b/tests/ptrconstptr.res
@@ -1,3 +1,3 @@
 void main() {
-	const char *const *y;
+	const char * const *y;
 }
-- 
2.21.1

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[Cocci] [PATCH v4 3/3] tests: Add test case to match const pointer variants

[Jaskaran Singh]

Pointer to const pointer and its variants would not match previously.
Add a test case for matching these types.

Signed-off-by: Jaskaran Singh <jaskaransingh7654321@gmail.com>
---
 tests/constptr.c     |  7 +++++++
 tests/constptr.cocci | 19 +++++++++++++++++++
 tests/constptr.res   |  7 +++++++
 3 files changed, 33 insertions(+)
 create mode 100644 tests/constptr.c
 create mode 100644 tests/constptr.cocci
 create mode 100644 tests/constptr.res

diff --git a/tests/constptr.c b/tests/constptr.c
new file mode 100644
index 00000000..13fe064c
--- /dev/null
+++ b/tests/constptr.c
@@ -0,0 +1,7 @@
+int main()
+{
+	const char * const * id;
+	const char * * const * id;
+	const char * const * * id;
+	const char * const id;
+}
diff --git a/tests/constptr.cocci b/tests/constptr.cocci
new file mode 100644
index 00000000..29f0aa96
--- /dev/null
+++ b/tests/constptr.cocci
@@ -0,0 +1,19 @@
+@ r0 @
+identifier id;
+@@
+const char * const *
+- id
++ id1
+;
+const char * * const *
+- id
++ id2
+;
+const char * const * *
+- id
++ id3
+;
+const char * const
+- id
++ id4
+;
diff --git a/tests/constptr.res b/tests/constptr.res
new file mode 100644
index 00000000..0af4de9a
--- /dev/null
+++ b/tests/constptr.res
@@ -0,0 +1,7 @@
+int main()
+{
+	const char * const * id1;
+	const char * * const * id2;
+	const char * const * * id3;
+	const char * const id4;
+}
-- 
2.21.1

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Re: [Cocci] [PATCH v4 1/3] parsing_c: Align C AST and Cocci AST for pointer

[Julia Lawall]

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@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@attr2,fun x -> (tq.qualifD, mk_tybis (Pointer (ptr x)) [$1])) }
> +       (attr1@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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Re: [Cocci] [PATCH v4 3/3] tests: Add test case to match const pointer variants

[Julia Lawall]

On Sun, 9 Feb 2020, Jaskaran Singh wrote:

> Pointer to const pointer and its variants would not match previously.
> Add a test case for matching these types.
>
> Signed-off-by: Jaskaran Singh <jaskaransingh7654321@gmail.com>
> ---
>  tests/constptr.c     |  7 +++++++
>  tests/constptr.cocci | 19 +++++++++++++++++++
>  tests/constptr.res   |  7 +++++++
>  3 files changed, 33 insertions(+)
>  create mode 100644 tests/constptr.c
>  create mode 100644 tests/constptr.cocci
>  create mode 100644 tests/constptr.res
>
> diff --git a/tests/constptr.c b/tests/constptr.c
> new file mode 100644
> index 00000000..13fe064c
> --- /dev/null
> +++ b/tests/constptr.c
> @@ -0,0 +1,7 @@
> +int main()
> +{
> +	const char * const * id;
> +	const char * * const * id;
> +	const char * const * * id;
> +	const char * const id;

As far as I can see in the Linux kernel, there is no space between two *s,
and there is no space before an identifier.

julia

> +}
> diff --git a/tests/constptr.cocci b/tests/constptr.cocci
> new file mode 100644
> index 00000000..29f0aa96
> --- /dev/null
> +++ b/tests/constptr.cocci
> @@ -0,0 +1,19 @@
> +@ r0 @
> +identifier id;
> +@@
> +const char * const *
> +- id
> ++ id1
> +;
> +const char * * const *
> +- id
> ++ id2
> +;
> +const char * const * *
> +- id
> ++ id3
> +;
> +const char * const
> +- id
> ++ id4
> +;
> diff --git a/tests/constptr.res b/tests/constptr.res
> new file mode 100644
> index 00000000..0af4de9a
> --- /dev/null
> +++ b/tests/constptr.res
> @@ -0,0 +1,7 @@
> +int main()
> +{
> +	const char * const * id1;
> +	const char * * const * id2;
> +	const char * const * * id3;
> +	const char * const id4;
> +}
> --
> 2.21.1
>
>
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Re: [Cocci] [PATCH v4 3/3] tests: Add test case to match const pointer variants

[Jaskaran Singh]

On Sun, 2020-02-09 at 17:48 +0100, Julia Lawall wrote:
> On Sun, 9 Feb 2020, Jaskaran Singh wrote:
> 
> > Pointer to const pointer and its variants would not match
> > previously.
> > Add a test case for matching these types.
> > 
> > Signed-off-by: Jaskaran Singh <jaskaransingh7654321@gmail.com>
> > ---
> >  tests/constptr.c     |  7 +++++++
> >  tests/constptr.cocci | 19 +++++++++++++++++++
> >  tests/constptr.res   |  7 +++++++
> >  3 files changed, 33 insertions(+)
> >  create mode 100644 tests/constptr.c
> >  create mode 100644 tests/constptr.cocci
> >  create mode 100644 tests/constptr.res
> > 
> > diff --git a/tests/constptr.c b/tests/constptr.c
> > new file mode 100644
> > index 00000000..13fe064c
> > --- /dev/null
> > +++ b/tests/constptr.c
> > @@ -0,0 +1,7 @@
> > +int main()
> > +{
> > +	const char * const * id;
> > +	const char * * const * id;
> > +	const char * const * * id;
> > +	const char * const id;
> 
> As far as I can see in the Linux kernel, there is no space between
> two *s,
> and there is no space before an identifier.
> 

Well, the test isn't replacing the type here. It's just replacing the
ident as per the matches. So I guess the spaces are preserved as in the
C file.
When replacing the type like say
-t x;
+t y;
Spaces are not added between the stars or the ident.

Sorry if I'm missing something. Do you mean that the C file/res file
should conform to the Linux style?

Cheers,
Jaskaran.

> julia
> 
> > +}
> > diff --git a/tests/constptr.cocci b/tests/constptr.cocci
> > new file mode 100644
> > index 00000000..29f0aa96
> > --- /dev/null
> > +++ b/tests/constptr.cocci
> > @@ -0,0 +1,19 @@
> > +@ r0 @
> > +identifier id;
> > +@@
> > +const char * const *
> > +- id
> > ++ id1
> > +;
> > +const char * * const *
> > +- id
> > ++ id2
> > +;
> > +const char * const * *
> > +- id
> > ++ id3
> > +;
> > +const char * const
> > +- id
> > ++ id4
> > +;
> > diff --git a/tests/constptr.res b/tests/constptr.res
> > new file mode 100644
> > index 00000000..0af4de9a
> > --- /dev/null
> > +++ b/tests/constptr.res
> > @@ -0,0 +1,7 @@
> > +int main()
> > +{
> > +	const char * const * id1;
> > +	const char * * const * id2;
> > +	const char * const * * id3;
> > +	const char * const id4;
> > +}
> > --
> > 2.21.1
> > 
> > 

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Re: [Cocci] [PATCH v4 3/3] tests: Add test case to match const pointer variants

[Julia Lawall]

On Sun, 9 Feb 2020, Jaskaran Singh wrote:

> On Sun, 2020-02-09 at 17:48 +0100, Julia Lawall wrote:
> > On Sun, 9 Feb 2020, Jaskaran Singh wrote:
> >
> > > Pointer to const pointer and its variants would not match
> > > previously.
> > > Add a test case for matching these types.
> > >
> > > Signed-off-by: Jaskaran Singh <jaskaransingh7654321@gmail.com>
> > > ---
> > >  tests/constptr.c     |  7 +++++++
> > >  tests/constptr.cocci | 19 +++++++++++++++++++
> > >  tests/constptr.res   |  7 +++++++
> > >  3 files changed, 33 insertions(+)
> > >  create mode 100644 tests/constptr.c
> > >  create mode 100644 tests/constptr.cocci
> > >  create mode 100644 tests/constptr.res
> > >
> > > diff --git a/tests/constptr.c b/tests/constptr.c
> > > new file mode 100644
> > > index 00000000..13fe064c
> > > --- /dev/null
> > > +++ b/tests/constptr.c
> > > @@ -0,0 +1,7 @@
> > > +int main()
> > > +{
> > > +	const char * const * id;
> > > +	const char * * const * id;
> > > +	const char * const * * id;
> > > +	const char * const id;
> >
> > As far as I can see in the Linux kernel, there is no space between
> > two *s,
> > and there is no space before an identifier.
> >
>
> Well, the test isn't replacing the type here. It's just replacing the
> ident as per the matches. So I guess the spaces are preserved as in the
> C file.
> When replacing the type like say
> -t x;
> +t y;
> Spaces are not added between the stars or the ident.

Yes, I agree.

>
> Sorry if I'm missing something. Do you mean that the C file/res file
> should conform to the Linux style?

I think it would be nicer if it did.

julia

> Cheers,
> Jaskaran.
>
> > julia
> >
> > > +}
> > > diff --git a/tests/constptr.cocci b/tests/constptr.cocci
> > > new file mode 100644
> > > index 00000000..29f0aa96
> > > --- /dev/null
> > > +++ b/tests/constptr.cocci
> > > @@ -0,0 +1,19 @@
> > > +@ r0 @
> > > +identifier id;
> > > +@@
> > > +const char * const *
> > > +- id
> > > ++ id1
> > > +;
> > > +const char * * const *
> > > +- id
> > > ++ id2
> > > +;
> > > +const char * const * *
> > > +- id
> > > ++ id3
> > > +;
> > > +const char * const
> > > +- id
> > > ++ id4
> > > +;
> > > diff --git a/tests/constptr.res b/tests/constptr.res
> > > new file mode 100644
> > > index 00000000..0af4de9a
> > > --- /dev/null
> > > +++ b/tests/constptr.res
> > > @@ -0,0 +1,7 @@
> > > +int main()
> > > +{
> > > +	const char * const * id1;
> > > +	const char * * const * id2;
> > > +	const char * const * * id3;
> > > +	const char * const id4;
> > > +}
> > > --
> > > 2.21.1
> > >
> > >
>
>
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