Re: [PATCH] Support _Complex in hard-VFP abi

[Will Newton <will dot newton at linaro dot org>]

On 11 August 2014 13:51, Yao Qi <yao@codesourcery.com> wrote:
> Hi,
> When we pass "-mfloat-abi=hard" flag in the GDB testing, we see the
> following fails,
>
> FAIL: gdb.base/callfuncs.exp: p t_float_complex_values(fc1, fc2)
> FAIL: gdb.base/callfuncs.exp: p t_float_complex_many_args(fc1, fc2, fc3, fc4, fc1, fc2, fc3, fc4, fc1, fc2, fc3, fc4, fc1, fc2, fc3, fc4)
> FAIL: gdb.base/callfuncs.exp: p t_double_complex_values(dc1, dc2)
> FAIL: gdb.base/callfuncs.exp: p t_double_complex_many_args(dc1, dc2, dc3, dc4, dc1, dc2, dc3, dc4, dc1, dc2, dc3, dc4, dc1, dc2, dc3, dc4)
> FAIL: gdb.base/callfuncs.exp: p t_long_double_complex_values(ldc1, ldc2)
> FAIL: gdb.base/callfuncs.exp: p t_long_double_complex_many_args(ldc1, ldc2, ldc3, ldc4, ldc1, ldc2, ldc3, ldc4, ldc1, ldc2, ldc3, ldc4, ldc1, ldc2, ldc3, ldc4)
> FAIL: gdb.base/callfuncs.exp: call inferior func with struct - returns float _Complex
> FAIL: gdb.base/callfuncs.exp: call inferior func with struct - returns double _Complex
>
> The hard-VFP ABI was supported by GDB overal, done by this patch
> https://sourceware.org/ml/gdb-patches/2009-07/msg00686.html but
> "vectors and complex types are not currently supported", mentioned in
> the patch.  As a result, these tests fail.
>
> This patch is to support _Complex types in hard-VFP abi.  As specified
> in "7.1.1, Procedure Call Standard for the ARM Arch", the layout of
> _Complex types is a struct, which is identical to the layout on amd64,
> so I copy Mark's comments to amd64 support.
>
> Regression tested on arm-none-eabi target.  OK to apply?
>
> gdb:
>
> 2014-08-11  Yao Qi  <yao@codesourcery.com>
>
>         * arm-tdep.c (arm_vfp_cprc_sub_candidate): Handle _Complex
>         types.
> ---
>  gdb/arm-tdep.c | 34 ++++++++++++++++++++++++++++++++--
>  1 file changed, 32 insertions(+), 2 deletions(-)

Apart from a couple of minor nits below this looks ok to me.

> diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
> index b6ec456..10e74cf 100644
> --- a/gdb/arm-tdep.c
> +++ b/gdb/arm-tdep.c
> @@ -3557,8 +3557,8 @@ arm_vfp_cprc_reg_char (enum arm_vfp_cprc_base_type b)
>     classified from *BASE_TYPE, or two types differently classified
>     from each other, return -1, otherwise return the total number of
>     base-type elements found (possibly 0 in an empty structure or
> -   array).  Vectors and complex types are not currently supported,
> -   matching the generic AAPCS support.  */
> +   array).  Vectors types are not currently supported, matching the

This should be "Vector types".

> +   generic AAPCS support.  */
>
>  static int
>  arm_vfp_cprc_sub_candidate (struct type *t,
> @@ -3589,6 +3589,36 @@ arm_vfp_cprc_sub_candidate (struct type *t,
>         }
>        break;
>
> +    case TYPE_CODE_COMPLEX:
> +      /* Arguments of complex T where T is one of the types float or
> +        double get treated as if they are implemented as:
> +
> +        struct complexT
> +        {
> +          T real;
> +          T imag;
> +        };*/

A line break before closing the comment might look nicer here.

> +      switch (TYPE_LENGTH (t))
> +       {
> +       case 8:
> +         if (*base_type == VFP_CPRC_UNKNOWN)
> +           *base_type = VFP_CPRC_SINGLE;
> +         else if (*base_type != VFP_CPRC_SINGLE)
> +           return -1;
> +         return 2;
> +
> +       case 16:
> +         if (*base_type == VFP_CPRC_UNKNOWN)
> +           *base_type = VFP_CPRC_DOUBLE;
> +         else if (*base_type != VFP_CPRC_DOUBLE)
> +           return -1;
> +         return 2;
> +
> +       default:
> +         return -1;
> +       }
> +      break;
> +
>      case TYPE_CODE_ARRAY:
>        {
>         int count;
> --
> 1.9.0
>



-- 
Will Newton
Toolchain Working Group, Linaro