vkd3d-shader: Implement remapping shader output registers to match the next shader's semantics.

Approved-by: Henri Verbeet (@hverbeet)
Approved-by: Alexandre Julliard (@julliard)
Merge-Request: https://gitlab.winehq.org/wine/vkd3d/-/merge_requests/280

include/vkd3d_shader.h

@@ -90,6 +90,11 @@ enum vkd3d_shader_structure_type
      * \since 1.9
      */
     VKD3D_SHADER_STRUCTURE_TYPE_SCAN_SIGNATURE_INFO,
+    /**
+     * The structure is a vkd3d_shader_next_stage_info structure.
+     * \since 1.9
+     */
+    VKD3D_SHADER_STRUCTURE_TYPE_NEXT_STAGE_INFO,
 
     VKD3D_FORCE_32_BIT_ENUM(VKD3D_SHADER_STRUCTURE_TYPE),
 };
@@ -1676,6 +1681,74 @@ struct vkd3d_shader_scan_signature_info
     struct vkd3d_shader_signature patch_constant;
 };
 
+/**
+ * Describes the mapping of a output varying register in a shader stage,
+ * to an input varying register in the following shader stage.
+ *
+ * This structure is used in struct vkd3d_shader_next_stage_info.
+ */
+struct vkd3d_shader_varying_map
+{
+    /**
+     * The signature index (in the output signature) of the output varying.
+     * If greater than or equal to the number of elements in the output
+     * signature, signifies that the varying is consumed by the next stage but
+     * not written by this one.
+     */
+    unsigned int output_signature_index;
+    /** The register index of the input varying to map this register to. */
+    unsigned int input_register_index;
+    /** The mask consumed by the destination register. */
+    unsigned int input_mask;
+};
+
+/**
+ * A chained structure which describes the next shader in the pipeline.
+ *
+ * This structure is optional, and should only be provided if there is in fact
+ * another shader in the pipeline.
+ * However, depending on the input and output formats, this structure may be
+ * necessary in order to generate shaders which correctly match each other.
+ * If the structure or its individual fields are not provided, vkd3d-shader
+ * will generate shaders which may be correct in isolation, but are not
+ * guaranteed to correctly match each other.
+ *
+ * This structure is passed to vkd3d_shader_compile() and extends
+ * vkd3d_shader_compile_info.
+ *
+ * This structure contains only input parameters.
+ *
+ * \since 1.9
+ */
+struct vkd3d_shader_next_stage_info
+{
+    /** Must be set to VKD3D_SHADER_STRUCTURE_TYPE_NEXT_STAGE_INFO. */
+    enum vkd3d_shader_structure_type type;
+    /** Optional pointer to a structure containing further parameters. */
+    const void *next;
+
+    /**
+     * A mapping of output varyings in this shader stage to input varyings
+     * in the next shader stage.
+     *
+     * This mapping should include exactly one element for each varying
+     * consumed by the next shader stage.
+     * If this shader stage outputs a varying that is not consumed by the next
+     * shader stage, that varying should be absent from this array.
+     *
+     * If this field is absent, vkd3d-shader will map varyings from one stage
+     * to another based on their register index.
+     * For Direct3D shader model 3.0, such a default mapping will be incorrect
+     * unless the registers are allocated in the same order, and hence this
+     * field is necessary to correctly match inter-stage varyings.
+     * This mapping may also be necessary under other circumstances where the
+     * varying interface does not match exactly.
+     */
+    const struct vkd3d_shader_varying_map *varying_map;
+    /** The number of registers provided in \ref varying_map. */
+    unsigned int varying_count;
+};
+
 #ifdef LIBVKD3D_SHADER_SOURCE
 # define VKD3D_SHADER_API VKD3D_EXPORT
 #else
@@ -1748,13 +1821,14 @@ VKD3D_SHADER_API const enum vkd3d_shader_target_type *vkd3d_shader_get_supported
  *
  * Depending on the source and target types, this function may support the
  * following chained structures:
+ * - vkd3d_shader_hlsl_source_info
  * - vkd3d_shader_interface_info
+ * - vkd3d_shader_next_stage_info
  * - vkd3d_shader_scan_descriptor_info
  * - vkd3d_shader_scan_signature_info
  * - vkd3d_shader_spirv_domain_shader_target_info
  * - vkd3d_shader_spirv_target_info
  * - vkd3d_shader_transform_feedback_info
- * - vkd3d_shader_hlsl_source_info
  *
  * \param compile_info A chained structure containing compilation parameters.
  *

libs/vkd3d-shader/ir.c

@@ -85,6 +85,75 @@ static void shader_instruction_eliminate_phase_instance_id(struct vkd3d_shader_i
         shader_register_eliminate_phase_addressing((struct vkd3d_shader_register *)&ins->dst[i].reg, instance_id);
 }
 
+static const struct vkd3d_shader_varying_map *find_varying_map(
+        const struct vkd3d_shader_next_stage_info *next_stage, unsigned int signature_idx)
+{
+    unsigned int i;
+
+    for (i = 0; i < next_stage->varying_count; ++i)
+    {
+        if (next_stage->varying_map[i].output_signature_index == signature_idx)
+            return &next_stage->varying_map[i];
+    }
+
+    return NULL;
+}
+
+static enum vkd3d_result remap_output_signature(struct vkd3d_shader_parser *parser,
+        const struct vkd3d_shader_compile_info *compile_info)
+{
+    struct shader_signature *signature = &parser->shader_desc.output_signature;
+    const struct vkd3d_shader_next_stage_info *next_stage;
+    unsigned int i;
+
+    if (!(next_stage = vkd3d_find_struct(compile_info->next, NEXT_STAGE_INFO)))
+        return VKD3D_OK;
+
+    for (i = 0; i < signature->element_count; ++i)
+    {
+        const struct vkd3d_shader_varying_map *map = find_varying_map(next_stage, i);
+        struct signature_element *e = &signature->elements[i];
+
+        if (map)
+        {
+            unsigned int input_mask = map->input_mask;
+
+            e->target_location = map->input_register_index;
+
+            /* It is illegal in Vulkan if the next shader uses the same varying
+             * location with a different mask. */
+            if (input_mask && input_mask != e->mask)
+            {
+                vkd3d_shader_parser_error(parser, VKD3D_SHADER_ERROR_VSIR_NOT_IMPLEMENTED,
+                        "Aborting due to not yet implemented feature: "
+                        "Output mask %#x does not match input mask %#x.",
+                        e->mask, input_mask);
+                return VKD3D_ERROR_NOT_IMPLEMENTED;
+            }
+        }
+        else
+        {
+            vkd3d_shader_parser_error(parser, VKD3D_SHADER_ERROR_VSIR_NOT_IMPLEMENTED,
+                    "Aborting due to not yet implemented feature: "
+                    "This stage outputs varyings not consumed by the next stage.");
+            return VKD3D_ERROR_NOT_IMPLEMENTED;
+        }
+    }
+
+    for (i = 0; i < next_stage->varying_count; ++i)
+    {
+        if (next_stage->varying_map[i].output_signature_index >= signature->element_count)
+        {
+            vkd3d_shader_parser_error(parser, VKD3D_SHADER_ERROR_VSIR_NOT_IMPLEMENTED,
+                    "Aborting due to not yet implemented feature: "
+                    "The next stage consumes varyings not written by this stage.");
+            return VKD3D_ERROR_NOT_IMPLEMENTED;
+        }
+    }
+
+    return VKD3D_OK;
+}
+
 struct hull_flattener
 {
     struct vkd3d_shader_instruction_array instructions;
@@ -1194,7 +1263,8 @@ static enum vkd3d_result instruction_array_normalise_flat_constants(struct vkd3d
     return VKD3D_OK;
 }
 
-enum vkd3d_result vkd3d_shader_normalise(struct vkd3d_shader_parser *parser)
+enum vkd3d_result vkd3d_shader_normalise(struct vkd3d_shader_parser *parser,
+        const struct vkd3d_shader_compile_info *compile_info)
 {
     struct vkd3d_shader_instruction_array *instructions = &parser->instructions;
     enum vkd3d_result result = VKD3D_OK;
@@ -1202,6 +1272,10 @@ enum vkd3d_result vkd3d_shader_normalise(struct vkd3d_shader_parser *parser)
     if (parser->shader_desc.is_dxil)
         return result;
 
+    if (parser->shader_version.type != VKD3D_SHADER_TYPE_PIXEL
+            && (result = remap_output_signature(parser, compile_info)) < 0)
+        return result;
+
     if (parser->shader_version.type == VKD3D_SHADER_TYPE_HULL
             && (result = instruction_array_flatten_hull_shader_phases(instructions)) >= 0)
     {

libs/vkd3d-shader/spirv.c

@@ -9542,7 +9542,7 @@ static int spirv_compiler_generate_spirv(struct spirv_compiler *compiler,
     compiler->location.column = 0;
     compiler->location.line = 1;
 
-    if ((result = vkd3d_shader_normalise(parser)) < 0)
+    if ((result = vkd3d_shader_normalise(parser, compile_info)) < 0)
         return result;
 
     instructions = parser->instructions;

libs/vkd3d-shader/vkd3d_shader_private.h

@@ -168,6 +168,8 @@ enum vkd3d_shader_error
     VKD3D_SHADER_WARNING_DXIL_INVALID_BLOCK_LENGTH      = 8302,
     VKD3D_SHADER_WARNING_DXIL_INVALID_MODULE_LENGTH     = 8303,
     VKD3D_SHADER_WARNING_DXIL_IGNORING_OPERANDS         = 8304,
+
+    VKD3D_SHADER_ERROR_VSIR_NOT_IMPLEMENTED             = 9000,
 };
 
 enum vkd3d_shader_opcode
@@ -1409,6 +1411,7 @@ void dxbc_writer_add_section(struct dxbc_writer *dxbc, uint32_t tag, const void
 void dxbc_writer_init(struct dxbc_writer *dxbc);
 int dxbc_writer_write(struct dxbc_writer *dxbc, struct vkd3d_shader_code *code);
 
-enum vkd3d_result vkd3d_shader_normalise(struct vkd3d_shader_parser *parser);
+enum vkd3d_result vkd3d_shader_normalise(struct vkd3d_shader_parser *parser,
+        const struct vkd3d_shader_compile_info *compile_info);
 
 #endif  /* __VKD3D_SHADER_PRIVATE_H */