Re: [PATCH] Fix comparison of array types

[Hannes Domani <ssbssa@yahoo.de>]

 Ping.


Am Freitag, 9. Februar 2024 um 20:46:35 MEZ hat Hannes Domani <ssbssa@yahoo.de> Folgendes geschrieben:

> Currently it's not possible to call functions if an argument is a
> pointer to an array:
> ```
> (gdb) l f
> 1      int f (int (*x)[2])
> 2      {
> 3        return x[0][1];
> 4      }
> 5
> 6      int main()
> 7      {
> 8        int a[2][2] = {{0, 1}, {2, 3}};
> 9        return f (a);
> 10      }
> (gdb) p f(a)
> Cannot resolve function f to any overloaded instance
> ```
>
> This happens because types_equal doesn't handle array types, so the
> function is never even considered as a possibility.
>
> With array type handling added, by comparing element types and array
> bounds, the same works:
> ```
> (gdb) p f(a)
> $1 = 1
> ```
>
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=15398
> Co-Authored-By: Keith Seitz <keiths@redhat.com>
> ---
> gdb/gdbtypes.c                    | 13 +++++++++++++
> gdb/testsuite/gdb.cp/converts.exp |  1 +
> 2 files changed, 14 insertions(+)
>
> diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
> index dcd7321d979..6c0d20b2daf 100644
> --- a/gdb/gdbtypes.c
> +++ b/gdb/gdbtypes.c
> @@ -4202,6 +4202,19 @@ types_equal (struct type *a, struct type *b)
>       return true;
>     }
>
> +  /* Two array types are the same if they have the same element types
> +    and array bounds.  */
> +  if (a->code () == TYPE_CODE_ARRAY)
> +    {
> +      if (!types_equal (a->target_type (), b->target_type ()))
> +    return false;
> +
> +      if (*a->bounds () != *b->bounds ())
> +    return false;
> +
> +      return true;
> +    }
> +
>   return false;
> }
>
> diff --git a/gdb/testsuite/gdb.cp/converts.exp b/gdb/testsuite/gdb.cp/converts.exp
> index bf608bdcccd..6ea21fec563 100644
> --- a/gdb/testsuite/gdb.cp/converts.exp
> +++ b/gdb/testsuite/gdb.cp/converts.exp
> @@ -48,6 +48,7 @@ gdb_test "p foo1_8 (bp)" "Using non-standard.*" "pointer to long int"
> gdb_test "p foo1_5 (b)" "= 15"            "pointer pointer to void pointer"
> gdb_test "p foo2_1 (b)" "= 21"            "pointer pointer to pointer pointer"
> gdb_test "p foo2_2 (b)" "Cannot resolve.*" "pointer pointer to array of arrays"
> +gdb_test "p foo2_2 (ba)" "= 22"            "array of arrays to array of arrays"
> gdb_test "p foo2_3 (b)" "= 23"            "pointer pointer to array of pointers"
> gdb_test "p foo2_4 (b)" "Cannot resolve.*" "pointer pointer to array of wrong pointers"
>
> --
> 2.35.1