[PATCH vkd3d 5/5] vkd3d-shader/hlsl: Correctly calculate offsets for array elements.

[Francisco Casas]

Hi,

The failing tests aside, this padding rule for array elements is 
an interesting find.

If this is correct, wouldn't that mean that we also have to use
hlsl_type_get_array_element_reg_size() in hlsl_type_calculate_reg_size()?

In particular, here
---
        case HLSL_CLASS_ARRAY:
        {
            unsigned int element_size = type->e.array.type->reg_size;

            assert(element_size);
            if (is_sm4)
                type->reg_size = (type->e.array.elements_count - 1) * align(element_size, 4) + element_size;
            else
                type->reg_size = type->e.array.elements_count * element_size;
            break;
        }
---

Also, it makes me wonder whether this rule only applies in sm4 and/or to uniform
arrays (I don't know a quick way to test that).

If I am not mistaken and we indeed have to change hlsl_type_calculate_reg_size(), 
then we would have to also take into account the padding in the
HLSL_CLASS_STRUCT case, when the struct contains array fields.


Thanks,
Francisco.


February 16, 2022 2:47 AM, "Zebediah Figura" <zfigura at codeweavers.com> wrote:

> Signed-off-by: Zebediah Figura <zfigura at codeweavers.com>
> ---
> Makefile.am | 2 +-
> libs/vkd3d-shader/hlsl.c | 7 +++++++
> libs/vkd3d-shader/hlsl.h | 1 +
> libs/vkd3d-shader/hlsl.y | 2 +-
> libs/vkd3d-shader/hlsl_codegen.c | 2 +-
> tests/hlsl-struct-array.shader_test | 19 +++++++++++++++++++
> 6 files changed, 30 insertions(+), 3 deletions(-)
> create mode 100644 tests/hlsl-struct-array.shader_test
> 
> diff --git a/Makefile.am b/Makefile.am
> index 75c5e4b1..74e3603c 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -93,6 +93,7 @@ vkd3d_shader_tests = \
> tests/hlsl-state-block-syntax.shader_test \
> tests/hlsl-static-initializer.shader_test \
> tests/hlsl-storage-qualifiers.shader_test \
> + tests/hlsl-struct-array.shader_test \
> tests/hlsl-struct-assignment.shader_test \
> tests/hlsl-struct-semantics.shader_test \
> tests/hlsl-vector-indexing.shader_test \
> @@ -326,7 +327,6 @@ XFAIL_TESTS = \
> tests/hlsl-majority-pragma.shader_test \
> tests/hlsl-majority-typedef.shader_test \
> tests/hlsl-mul.shader_test \
> - tests/hlsl-nested-arrays.shader_test \
> tests/hlsl-numeric-constructor-truncation.shader_test \
> tests/hlsl-numeric-types.shader_test \
> tests/hlsl-operations.shader_test \
> diff --git a/libs/vkd3d-shader/hlsl.c b/libs/vkd3d-shader/hlsl.c
> index 8a0f4b01..9c511018 100644
> --- a/libs/vkd3d-shader/hlsl.c
> +++ b/libs/vkd3d-shader/hlsl.c
> @@ -202,6 +202,13 @@ static void hlsl_type_calculate_reg_size(struct hlsl_ctx *ctx, struct
> hlsl_type
> }
> }
> 
> +/* Returns the size of a type, considered as part of an array of that type.
> + * As such it includes padding after the type. */
> +unsigned int hlsl_type_get_array_element_reg_size(const struct hlsl_type *type)
> +{
> + return align(type->reg_size, 4);
> +}
> +
> static struct hlsl_type *hlsl_new_type(struct hlsl_ctx *ctx, const char *name, enum hlsl_type_class
> type_class,
> enum hlsl_base_type base_type, unsigned dimx, unsigned dimy)
> {
> diff --git a/libs/vkd3d-shader/hlsl.h b/libs/vkd3d-shader/hlsl.h
> index 9b1c9ad3..8ac3e0c5 100644
> --- a/libs/vkd3d-shader/hlsl.h
> +++ b/libs/vkd3d-shader/hlsl.h
> @@ -780,6 +780,7 @@ bool hlsl_scope_add_type(struct hlsl_scope *scope, struct hlsl_type *type);
> struct hlsl_type *hlsl_type_clone(struct hlsl_ctx *ctx, struct hlsl_type *old,
> unsigned int default_majority, unsigned int modifiers);
> unsigned int hlsl_type_component_count(struct hlsl_type *type);
> +unsigned int hlsl_type_get_array_element_reg_size(const struct hlsl_type *type);
> unsigned int hlsl_type_get_sm4_offset(const struct hlsl_type *type, unsigned int offset);
> bool hlsl_types_are_equal(const struct hlsl_type *t1, const struct hlsl_type *t2);
> 
> diff --git a/libs/vkd3d-shader/hlsl.y b/libs/vkd3d-shader/hlsl.y
> index 459ad03b..70109780 100644
> --- a/libs/vkd3d-shader/hlsl.y
> +++ b/libs/vkd3d-shader/hlsl.y
> @@ -607,7 +607,7 @@ static struct hlsl_ir_load *add_array_load(struct hlsl_ctx *ctx, struct list
> *in
> return NULL;
> }
> 
> - if (!(c = hlsl_new_uint_constant(ctx, data_type->reg_size, loc)))
> + if (!(c = hlsl_new_uint_constant(ctx, hlsl_type_get_array_element_reg_size(data_type), loc)))
> return NULL;
> list_add_tail(instrs, &c->node.entry);
> if (!(mul = hlsl_new_binary_expr(ctx, HLSL_OP2_MUL, index, &c->node)))
> diff --git a/libs/vkd3d-shader/hlsl_codegen.c b/libs/vkd3d-shader/hlsl_codegen.c
> index 25f038d4..ccc95c90 100644
> --- a/libs/vkd3d-shader/hlsl_codegen.c
> +++ b/libs/vkd3d-shader/hlsl_codegen.c
> @@ -634,7 +634,7 @@ static bool split_array_copies(struct hlsl_ctx *ctx, struct hlsl_ir_node
> *instr,
> if (type->type != HLSL_CLASS_ARRAY)
> return false;
> element_type = type->e.array.type;
> - element_size = element_type->reg_size;
> + element_size = hlsl_type_get_array_element_reg_size(element_type);
> 
> for (i = 0; i < type->e.array.elements_count; ++i)
> {
> diff --git a/tests/hlsl-struct-array.shader_test b/tests/hlsl-struct-array.shader_test
> new file mode 100644
> index 00000000..01996a50
> --- /dev/null
> +++ b/tests/hlsl-struct-array.shader_test
> @@ -0,0 +1,19 @@
> +% In SM4, arrays are always aligned to the next vec4, although structs are not.
> +
> +[pixel shader]
> +uniform struct
> +{
> + float p, q;
> +} colours[3];
> +
> +float4 main() : sv_target
> +{
> + return float4(colours[0].q, colours[1].p, colours[2].q, colours[2].p);
> +}
> +
> +[test]
> +uniform 0 float4 0.1 0.2 0.0 0.0
> +uniform 4 float4 0.3 0.4 0.0 0.0
> +uniform 8 float4 0.5 0.6 0.0 0.0
> +draw quad
> +probe all rgba (0.2, 0.3, 0.6, 0.5)
> -- 
> 2.34.1