[PATCH vkd3d 1/5] vkd3d-shader/hlsl: Allocate textures for SM4.

[Zebediah Figura]

On 10/14/21 3:45 AM, Matteo Bruni wrote:
> On Tue, Oct 12, 2021 at 4:59 AM Zebediah Figura <zfigura at codeweavers.com> wrote:
>>
>> Signed-off-by: Zebediah Figura <zfigura at codeweavers.com>
>> ---
>>   libs/vkd3d-shader/hlsl_codegen.c | 63 ++++++++++++++++++++++++++++++++
>>   1 file changed, 63 insertions(+)
>>
>> diff --git a/libs/vkd3d-shader/hlsl_codegen.c b/libs/vkd3d-shader/hlsl_codegen.c
>> index 00fe76b2f..bf93a03df 100644
>> --- a/libs/vkd3d-shader/hlsl_codegen.c
>> +++ b/libs/vkd3d-shader/hlsl_codegen.c
>> @@ -1197,6 +1197,64 @@ static void allocate_buffers(struct hlsl_ctx *ctx)
>>       }
>>   }
>>
>> +static const struct hlsl_ir_var *get_reserved_texture(struct hlsl_ctx *ctx, uint32_t index)
>> +{
>> +    const struct hlsl_ir_var *var;
>> +
>> +    LIST_FOR_EACH_ENTRY(var, &ctx->extern_vars, const struct hlsl_ir_var, extern_entry)
>> +    {
>> +        if (var->has_resource_access && var->reg_reservation.type == 't' && var->reg_reservation.index == index)
>> +            return var;
>> +    }
>> +    return NULL;
>> +}
>> +
>> +static void allocate_textures(struct hlsl_ctx *ctx)
>> +{
>> +    struct hlsl_ir_var *var;
>> +    uint32_t index = 0;
>> +
>> +    LIST_FOR_EACH_ENTRY(var, &ctx->extern_vars, struct hlsl_ir_var, extern_entry)
>> +    {
>> +        if (!var->has_resource_access || var->data_type->type != HLSL_CLASS_OBJECT
>> +                || var->data_type->base_type != HLSL_TYPE_TEXTURE)
>> +            continue;
>> +
>> +        if (var->reg_reservation.type == 't')
>> +        {
>> +            const struct hlsl_ir_var *reserved_texture = get_reserved_texture(ctx, var->reg_reservation.index);
>> +
>> +            if (reserved_texture && reserved_texture != var)
>> +            {
>> +                hlsl_error(ctx, var->loc, VKD3D_SHADER_ERROR_HLSL_OVERLAPPING_RESERVATIONS,
>> +                        "Multiple textures bound to t%u.", var->reg_reservation.index);
>> +                hlsl_note(ctx, reserved_texture->loc, VKD3D_SHADER_LOG_ERROR,
>> +                        "Texture '%s' is already bound to t%u.", reserved_texture->name,
>> +                        var->reg_reservation.index);
>> +            }
>> +
>> +            var->reg.id = var->reg_reservation.index;
>> +            var->reg.allocated = true;
>> +            TRACE("Allocated reserved %s to t%u.\n", var->name, index);
>> +        }
>> +        else if (!var->reg_reservation.type)
>> +        {
>> +            while (get_reserved_texture(ctx, index))
>> +                ++index;
>> +
>> +            var->reg.id = index;
>> +            var->reg.allocated = true;
>> +            TRACE("Allocated %s to t%u.\n", var->name, index);
>> +            ++index;
>> +        }
>> +        else
>> +        {
>> +            hlsl_error(ctx, var->loc, VKD3D_SHADER_ERROR_HLSL_INVALID_RESERVATION,
>> +                    "Textures must be bound to register type 't'.");
>> +        }
>> +    }
>> +}
> 
> The reservation lookup seems... suboptimal. It's not new (it's
> basically the same as what we do for buffers already) and probably
> there won't be that many extern variables in the usual cases, so maybe
> this is not going to be an issue in practice. It does kind of raise a
> red flag for me though...
> I guess let's keep this in mind if we ever happen to encounter
> performance issues.
> 

I don't like how similar it looks to buffers (and samplers and UAVs), 
but it's not clear to me how to deduplicate it while not being horribly 
structured.

I certainly haven't seen shaders with a ton of externs yet.