Re: [PATCH] Fix accessing a function's fields (parameters) from Python (PR 18073)

[Simon Marchi <simon dot marchi at polymtl dot ca>]

On 28 September 2015 at 00:43, Simon Marchi <simon.marchi@polymtl.ca> wrote:
> Since 7.4, gdb doesn't allow calling .fields() on a function type, even
> though the documentation states it should return a list corresponding to
> the function's parameters.  This patch restores the intended behaviour
> and adds a test for it.
>
> Reg-tested on Arch Linux x86-64.
>
> gdb/ChangeLog:
>
>         PR python/18073
>         * python/py-type.c (typy_get_composite): Allow returning a
>         function type.
>
> gdb/testsuite/ChangeLog:
>
>         PR python/18073
>         * gdb.python/py-type.c (C::a_method): New.
>         (C::a_const_method): New.
>         (C::a_static_method): New.
>         (a_function): New.
>         * gdb.python/py-type.exp (test_fields): Test getting fields
>         from function and method.
> ---
>  gdb/python/py-type.c                 |  5 +++--
>  gdb/testsuite/gdb.python/py-type.c   | 34 ++++++++++++++++++++++++++++++++--
>  gdb/testsuite/gdb.python/py-type.exp | 28 ++++++++++++++++++++++++----
>  3 files changed, 59 insertions(+), 8 deletions(-)
>
> diff --git a/gdb/python/py-type.c b/gdb/python/py-type.c
> index 7b3f8f9..ef4e719 100644
> --- a/gdb/python/py-type.c
> +++ b/gdb/python/py-type.c
> @@ -495,10 +495,11 @@ typy_get_composite (struct type *type)
>       exception.  */
>    if (TYPE_CODE (type) != TYPE_CODE_STRUCT
>        && TYPE_CODE (type) != TYPE_CODE_UNION
> -      && TYPE_CODE (type) != TYPE_CODE_ENUM)
> +      && TYPE_CODE (type) != TYPE_CODE_ENUM
> +      && TYPE_CODE (type) != TYPE_CODE_FUNC)
>      {
>        PyErr_SetString (PyExc_TypeError,
> -                      "Type is not a structure, union, or enum type.");
> +                      "Type is not a structure, union, enum, or function type.");
>        return NULL;
>      }
>
> diff --git a/gdb/testsuite/gdb.python/py-type.c b/gdb/testsuite/gdb.python/py-type.c
> index e3901cc..36ce1d8 100644
> --- a/gdb/testsuite/gdb.python/py-type.c
> +++ b/gdb/testsuite/gdb.python/py-type.c
> @@ -35,6 +35,24 @@ struct C
>  {
>    int c;
>    int d;
> +
> +  int
> +  a_method (int x, char y)
> +    {
> +      return x + y;
> +    }
> +
> +  int
> +  a_const_method (int x, char y) const
> +    {
> +      return x + y;
> +    }
> +
> +  static int
> +  a_static_method (int x, char y)
> +    {
> +      return x + y;
> +    }
>  };
>
>  struct D : C
> @@ -59,6 +77,12 @@ enum E
>  struct s vec_data_1 = {1, 1};
>  struct s vec_data_2 = {1, 2};
>
> +static int
> +a_function (int x, char y)
> +{
> +  return x + y;
> +}
> +
>  int
>  main ()
>  {
> @@ -72,15 +96,21 @@ main ()
>    D d;
>    d.e = 3;
>    d.f = 4;
> +
> +  c.a_method (0, 1);
> +  c.a_const_method (0, 1);
> +  C::a_static_method (0, 1);
>  #endif
>    enum E e;
> -
> +
>    st.a = 3;
>    st.b = 5;
>
>    e = v2;
>
>    ss.x = 100;
> -
> +
> +  a_function (0, 1);
> +
>    return 0;      /* break to inspect struct and array.  */
>  }
> diff --git a/gdb/testsuite/gdb.python/py-type.exp b/gdb/testsuite/gdb.python/py-type.exp
> index 58a2394..26126eb 100644
> --- a/gdb/testsuite/gdb.python/py-type.exp
> +++ b/gdb/testsuite/gdb.python/py-type.exp
> @@ -75,6 +75,21 @@ proc test_fields {lang} {
>        gdb_test "python print (c.type == gdb.parse_and_eval('d').type)" "False"
>        gdb_test "python print (c.type == gdb.parse_and_eval('d').type.fields()\[0\].type)" \
>           "True"
> +
> +      # Test fields of a method (its parameters)
> +      gdb_test "python print (len (gdb.parse_and_eval ('C::a_method').type.fields ()))" "3"
> +      gdb_test "python print (gdb.parse_and_eval ('C::a_method').type.fields ()\[0\].type)" "C \\* const"
> +      gdb_test "python print (gdb.parse_and_eval ('C::a_method').type.fields ()\[1\].type)" "int"
> +      gdb_test "python print (gdb.parse_and_eval ('C::a_method').type.fields ()\[2\].type)" "char"
> +
> +      gdb_test "python print (len (gdb.parse_and_eval ('C::a_const_method').type.fields ()))" "3"
> +      gdb_test "python print (gdb.parse_and_eval ('C::a_const_method').type.fields ()\[0\].type)" "const C \\* const"
> +      gdb_test "python print (gdb.parse_and_eval ('C::a_const_method').type.fields ()\[1\].type)" "int"
> +      gdb_test "python print (gdb.parse_and_eval ('C::a_const_method').type.fields ()\[2\].type)" "char"
> +
> +      gdb_test "python print (len (gdb.parse_and_eval ('C::a_static_method').type.fields ()))" "2"
> +      gdb_test "python print (gdb.parse_and_eval ('C::a_static_method').type.fields ()\[0\].type)" "int"
> +      gdb_test "python print (gdb.parse_and_eval ('C::a_static_method').type.fields ()\[1\].type)" "char"
>      }
>
>      # Test normal fields usage in structs.
> @@ -109,10 +124,10 @@ proc test_fields {lang} {
>      gdb_test "python print (not not st.type)" "True" "Check conversion to bool"
>
>      # Test rejection of mapping operations on scalar types
> -    gdb_test "python print (len (st.type\['a'\].type))" "TypeError: Type is not a structure, union, or enum type.*"
> -    gdb_test "python print (st.type\['a'\].type.has_key ('x'))" "TypeError: Type is not a structure, union, or enum type.*"
> -    gdb_test "python print (st.type\['a'\].type.keys ())" "TypeError: Type is not a structure, union, or enum type.*"
> -    gdb_test "python print (st.type\['a'\].type\['x'\])" "TypeError: Type is not a structure, union, or enum type.*"
> +    gdb_test "python print (len (st.type\['a'\].type))" "TypeError: Type is not a structure, union, enum, or function type.*"
> +    gdb_test "python print (st.type\['a'\].type.has_key ('x'))" "TypeError: Type is not a structure, union, enum, or function type.*"
> +    gdb_test "python print (st.type\['a'\].type\['x'\])" "TypeError: Type is not a structure, union, enum, or function type.*"
> +    gdb_test "python print (st.type\['a'\].type.keys ())" "TypeError: Type is not a structure, union, enum, or function type.*"
>
>      # Test conversion to bool on scalar types
>      gdb_test "python print (not not st.type\['a'\].type)" "True"
> @@ -148,6 +163,11 @@ proc test_fields {lang} {
>      gdb_test "python print (vec1 == vec2)" "True"
>      gdb_py_test_silent_cmd "python vec3 = vec_data_2.cast(ar\[0\].type.vector(1))" "set vec3" 1
>      gdb_test "python print (vec1 == vec3)" "False"
> +
> +    # Test fields of a function (its parameters)
> +    gdb_test "python print (len (gdb.parse_and_eval ('a_function').type.fields ()))" "2"
> +    gdb_test "python print (gdb.parse_and_eval ('a_function').type.fields ()\[0\].type)" "int"
> +    gdb_test "python print (gdb.parse_and_eval ('a_function').type.fields ()\[1\].type)" "char"
>    }
>  }
>
> --
> 2.5.3
>

Ping.