[Mesa-dev] [PATCH V7 20/24] glsl: link uniform block arrays of arrays

Samuel Iglesias Gonsálvez siglesias at igalia.com
Thu Oct 8 05:10:00 PDT 2015


I have minor comments below. I don't see anything wrong here, but maybe
others with more knowledge of this area want to review this patch as well.

With the minor comments addressed,

Reviewed-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>

On 07/10/15 00:47, Timothy Arceri wrote:
> This adds support for setting up the UniformBlock structures for AoA
> and also adds support for resizing AoA blocks with a packed layout.
> ---
>  src/glsl/link_uniform_block_active_visitor.cpp | 168 ++++++++++++++++---------
>  src/glsl/link_uniform_block_active_visitor.h   |  13 +-
>  src/glsl/link_uniform_blocks.cpp               | 160 +++++++++++++++--------
>  3 files changed, 229 insertions(+), 112 deletions(-)
> 
> diff --git a/src/glsl/link_uniform_block_active_visitor.cpp b/src/glsl/link_uniform_block_active_visitor.cpp
> index bcf17fe..422739a 100644
> --- a/src/glsl/link_uniform_block_active_visitor.cpp
> +++ b/src/glsl/link_uniform_block_active_visitor.cpp
> @@ -71,6 +71,88 @@ process_block(void *mem_ctx, struct hash_table *ht, ir_variable *var)
>     return NULL;
>  }
>  
> +/* For arrays of arrays this function will give us a middle ground between
> + * detecting inactive uniform blocks and structuring them in a way that makes
> + * it easy to calculate the offset for indirect indexing.
> + *
> + * For example given the shader:
> + *
> + *   uniform ArraysOfArraysBlock
> + *   {
> + *      vec4 a;
> + *   } i[3][4][5];
> + *
> + *   void main()
> + *   {
> + *      vec4 b = i[0][1][1].a;
> + *      gl_Position = i[2][2][3].a + b;
> + *   }
> + *
> + * There are only 2 active blocks above but for the sake of indirect indexing
> + * and not over complicating the code we will end up with a count of 8.
> + * Here each dimension has 2 different indices counted so we end up with 2*2*2
> + */
> +struct uniform_block_array_elements **
> +process_arrays(void *mem_ctx, ir_dereference_array *ir,
> +               struct link_uniform_block_active *block)
> +{
> +   if (ir) {
> +      struct uniform_block_array_elements **ub_array_ptr =
> +         process_arrays(mem_ctx, ir->array->as_dereference_array(), block);
> +      if (*ub_array_ptr == NULL) {
> +         *ub_array_ptr = rzalloc(mem_ctx, struct uniform_block_array_elements);
> +         (*ub_array_ptr)->ir = ir;
> +      }
> +
> +      struct uniform_block_array_elements *ub_array = *ub_array_ptr;
> +      ir_constant *c = ir->array_index->as_constant();
> +      if (c) {
> +         /* Index is a constant, so mark just that element used,
> +          * if not already.
> +          */
> +         const unsigned idx = c->get_uint_component(0);
> +
> +         unsigned i;
> +         for (i = 0; i < ub_array->num_array_elements; i++) {
> +            if (ub_array->array_elements[i] == idx)
> +               break;
> +         }
> +
> +         assert(i <= ub_array->num_array_elements);
> +
> +         if (i == ub_array->num_array_elements) {
> +            ub_array->array_elements = reralloc(mem_ctx,
> +                                                ub_array->array_elements,
> +                                                unsigned,
> +                                                ub_array->num_array_elements + 1);
> +
> +            ub_array->array_elements[ub_array->num_array_elements] = idx;
> +
> +            ub_array->num_array_elements++;
> +         }
> +      } else {
> +         /* The array index is not a constant,
> +          * so mark the entire array used.
> +          */
> +         assert(ir->array->type->is_array());
> +         if (ub_array->num_array_elements < ir->array->type->length) {
> +            ub_array->num_array_elements = ir->array->type->length;
> +            ub_array->array_elements = reralloc(mem_ctx,
> +                                                ub_array->array_elements,
> +                                                unsigned,
> +                                                ub_array->num_array_elements);
> +
> +            for (unsigned i = 0; i < ub_array->num_array_elements; i++) {
> +               ub_array->array_elements[i] = i;
> +            }
> +         }
> +      }
> +      return &ub_array->array;
> +   } else {
> +      return &block->array;
> +   }
> +}
> +
>  ir_visitor_status
>  link_uniform_block_active_visitor::visit(ir_variable *var)
>  {
> @@ -101,24 +183,30 @@ link_uniform_block_active_visitor::visit(ir_variable *var)
>        return visit_stop;
>     }
>  
> -   assert(b->num_array_elements == 0);
> -   assert(b->array_elements == NULL);
> +   assert(b->array == NULL);
>     assert(b->type != NULL);
>     assert(!b->type->is_array() || b->has_instance_name);
>  
>     /* For uniform block arrays declared with a shared or std140 layout
>      * qualifier, mark all its instances as used.
>      */
> -   if (b->type->is_array() && b->type->length > 0) {
> -      b->num_array_elements = b->type->length;
> -      b->array_elements = reralloc(this->mem_ctx,
> -                                   b->array_elements,
> -                                   unsigned,
> -                                   b->num_array_elements);
> -
> -      for (unsigned i = 0; i < b->num_array_elements; i++) {
> -         b->array_elements[i] = i;
> +   const glsl_type *type = b->type;
> +   struct uniform_block_array_elements **ub_array = &b->array;
> +   while (type->is_array()) {
> +      assert(b->type->length > 0);
> +

assert(type->length > 0);

> +      *ub_array = rzalloc(this->mem_ctx, struct uniform_block_array_elements);
> +      (*ub_array)->num_array_elements = type->length;
> +      (*ub_array)->array_elements = reralloc(this->mem_ctx,
> +                                             (*ub_array)->array_elements,
> +                                             unsigned,
> +                                             (*ub_array)->num_array_elements);
> +
> +      for (unsigned i = 0; i < (*ub_array)->num_array_elements; i++) {
> +         (*ub_array)->array_elements[i] = i;
>        }
> +      ub_array = &(*ub_array)->array;
> +      type = type->fields.array;
>     }
>  
>     return visit_continue;
> @@ -127,7 +215,13 @@ link_uniform_block_active_visitor::visit(ir_variable *var)
>  ir_visitor_status
>  link_uniform_block_active_visitor::visit_enter(ir_dereference_array *ir)
>  {
> -   ir_dereference_variable *const d = ir->array->as_dereference_variable();
> +   /* cycle through arrays of arrays */
> +   ir_dereference_array *base_ir = ir;
> +   while (base_ir->array->ir_type == ir_type_dereference_array)
> +      base_ir = base_ir->array->as_dereference_array();
> +
> +   ir_dereference_variable *const d =
> +      base_ir->array->as_dereference_variable();
>     ir_variable *const var = (d == NULL) ? NULL : d->var;
>  
>     /* If the r-value being dereferenced is not a variable (e.g., a field of a
> @@ -158,55 +252,16 @@ link_uniform_block_active_visitor::visit_enter(ir_dereference_array *ir)
>     /* Block arrays must be declared with an instance name.
>      */
>     assert(b->has_instance_name);
> -   assert((b->num_array_elements == 0) == (b->array_elements == NULL));
>     assert(b->type != NULL);
>  
>     /* If the block array was declared with a shared or
>      * std140 layout qualifier, all its instances have been already marked
>      * as used in link_uniform_block_active_visitor::visit(ir_variable *).
>      */
> -   if (var->get_interface_type()->interface_packing !=
> -       GLSL_INTERFACE_PACKING_PACKED)
> -      return visit_continue_with_parent;
> -
> -   ir_constant *c = ir->array_index->as_constant();
> -
> -   if (c) {
> -      /* Index is a constant, so mark just that element used, if not already */
> -      const unsigned idx = c->get_uint_component(0);
> -
> -      unsigned i;
> -      for (i = 0; i < b->num_array_elements; i++) {
> -         if (b->array_elements[i] == idx)
> -            break;
> -      }
> -
> -      assert(i <= b->num_array_elements);
> -
> -      if (i == b->num_array_elements) {
> -         b->array_elements = reralloc(this->mem_ctx,
> -                                      b->array_elements,
> -                                      unsigned,
> -                                      b->num_array_elements + 1);
> -
> -         b->array_elements[b->num_array_elements] = idx;
> -
> -         b->num_array_elements++;
> -      }
> -   } else {
> -      /* The array index is not a constant, so mark the entire array used. */
> -      assert(b->type->is_array());
> -      if (b->num_array_elements < b->type->length) {
> -         b->num_array_elements = b->type->length;
> -         b->array_elements = reralloc(this->mem_ctx,
> -                                      b->array_elements,
> -                                      unsigned,
> -                                      b->num_array_elements);
> -
> -         for (unsigned i = 0; i < b->num_array_elements; i++) {
> -            b->array_elements[i] = i;
> -         }
> -      }
> +   if (var->get_interface_type()->interface_packing ==
> +       GLSL_INTERFACE_PACKING_PACKED) {
> +      b->var = var;
> +      process_arrays(this->mem_ctx, ir, b);
>     }
>  
>     return visit_continue_with_parent;
> @@ -234,8 +289,7 @@ link_uniform_block_active_visitor::visit(ir_dereference_variable *ir)
>        return visit_stop;
>     }
>  
> -   assert(b->num_array_elements == 0);
> -   assert(b->array_elements == NULL);
> +   assert(b->array == NULL);
>     assert(b->type != NULL);
>  
>     return visit_continue;
> diff --git a/src/glsl/link_uniform_block_active_visitor.h b/src/glsl/link_uniform_block_active_visitor.h
> index b663a88..afb52c1 100644
> --- a/src/glsl/link_uniform_block_active_visitor.h
> +++ b/src/glsl/link_uniform_block_active_visitor.h
> @@ -28,11 +28,20 @@
>  #include "ir.h"
>  #include "util/hash_table.h"
>  
> +struct uniform_block_array_elements {
> +   unsigned *array_elements;
> +   unsigned num_array_elements;
> +
> +   ir_dereference_array *ir;
> +
> +   struct uniform_block_array_elements *array;
> +};
> +
>  struct link_uniform_block_active {
>     const glsl_type *type;
> +   ir_variable *var;
>  
> -   unsigned *array_elements;
> -   unsigned num_array_elements;
> +   struct uniform_block_array_elements *array;
>  
>     unsigned binding;
>  
> diff --git a/src/glsl/link_uniform_blocks.cpp b/src/glsl/link_uniform_blocks.cpp
> index 7ceffee..5285d8d 100644
> --- a/src/glsl/link_uniform_blocks.cpp
> +++ b/src/glsl/link_uniform_blocks.cpp
> @@ -116,7 +116,7 @@ private:
>           char *open_bracket = strchr(v->IndexName, '[');
>           assert(open_bracket != NULL);
>  
> -         char *close_bracket = strchr(open_bracket, ']');
> +         char *close_bracket = strchr(open_bracket, '.') - 1;
>           assert(close_bracket != NULL);
>  

I would assert *close_bracket is ']'.

>           /* Length of the tail without the ']' but with the NUL.
> @@ -185,6 +185,91 @@ struct block {
>     bool has_instance_name;
>  };
>  
> +static void
> +process_block_array(struct uniform_block_array_elements *ub_array, char **name,
> +                    size_t name_length, gl_uniform_block *blocks,
> +                    ubo_visitor *parcel, gl_uniform_buffer_variable *variables,
> +                    const struct link_uniform_block_active *const b,
> +                    unsigned *block_index, unsigned *binding_offset,
> +                    struct gl_context *ctx, struct gl_shader_program *prog)
> +{
> +   if (ub_array) {
> +      for (unsigned j = 0; j < ub_array->num_array_elements; j++) {
> +	 size_t new_length = name_length;
> +

Indentation

> +         /* Append the subscript to the current variable name */
> +         ralloc_asprintf_rewrite_tail(name, &new_length, "[%u]",
> +                                      ub_array->array_elements[j]);
> +
> +         process_block_array(ub_array->array, name, new_length, blocks,
> +                             parcel, variables, b, block_index,
> +                             binding_offset, ctx, prog);
> +      }
> +   } else {
> +      unsigned i = *block_index;
> +      const glsl_type *type =  b->type->without_array();
> +
> +      blocks[i].Name = ralloc_strdup(blocks, *name);
> +      blocks[i].Uniforms = &variables[(*parcel).index];
> +
> +      /* The GL_ARB_shading_language_420pack spec says:
> +       *
> +       *     "If the binding identifier is used with a uniform block
> +       *     instanced as an array then the first element of the array
> +       *     takes the specified block binding and each subsequent
> +       *     element takes the next consecutive uniform block binding
> +       *     point."
> +       */
> +      blocks[i].Binding = (b->has_binding) ? b->binding + *binding_offset : 0;
> +
> +      blocks[i].UniformBufferSize = 0;
> +      blocks[i]._Packing = gl_uniform_block_packing(type->interface_packing);
> +
> +      parcel->process(type, blocks[i].Name);
> +
> +      blocks[i].UniformBufferSize = parcel->buffer_size;
> +
> +      /* Check SSBO size is lower than maximum supported size for SSBO */
> +      if (b->is_shader_storage &&
> +          parcel->buffer_size > ctx->Const.MaxShaderStorageBlockSize) {
> +         linker_error(prog, "shader storage block `%s' has size %d, "
> +                      "which is larger than than the maximum allowed (%d)",
> +                      b->type->name,
> +                      parcel->buffer_size,
> +                      ctx->Const.MaxShaderStorageBlockSize);
> +      }
> +      blocks[i].NumUniforms =
> +         (unsigned)(ptrdiff_t)(&variables[parcel->index] - blocks[i].Uniforms);
> +      blocks[i].IsShaderStorage = b->is_shader_storage;
> +
> +      *block_index = *block_index + 1;
> +      *binding_offset = *binding_offset + 1;
> +   }
> +}
> +
> +/* This function resizes the array types of the block so that later we can use
> + * this new size to correctly calculate the offest for indirect indexing.

s/offest/offset

> + */
> +const glsl_type *
> +resize_block_array(const glsl_type *type,
> +                   struct uniform_block_array_elements *ub_array)

This should be a static function, right?

> +{
> +   if (type->is_array()) {
> +      struct uniform_block_array_elements *child_array =
> +         type->fields.array->is_array() ? ub_array->array : NULL;
> +      const glsl_type *new_child_type =
> +         resize_block_array(type->fields.array, child_array);
> +
> +      const glsl_type *new_type =
> +         glsl_type::get_array_instance(new_child_type,
> +                                       ub_array->num_array_elements);
> +      ub_array->ir->array->type = new_type;
> +      return new_type;
> +   } else {
> +      return type;
> +   }
> +}
> +
>  unsigned
>  link_uniform_blocks(void *mem_ctx,
>                      struct gl_context *ctx,
> @@ -223,21 +308,25 @@ link_uniform_blocks(void *mem_ctx,
>     struct hash_entry *entry;
>  
>     hash_table_foreach (block_hash, entry) {
> -      const struct link_uniform_block_active *const b =
> -         (const struct link_uniform_block_active *) entry->data;
> +      struct link_uniform_block_active *const b =
> +         (struct link_uniform_block_active *) entry->data;
>  
> -      const glsl_type *const block_type =
> -         b->type->is_array() ? b->type->fields.array : b->type;
> +      assert((b->array != NULL) == b->type->is_array());
>  
> -      assert((b->num_array_elements > 0) == b->type->is_array());
> +      if (b->array != NULL &&
> +          (b->type->without_array()->interface_packing ==
> +           GLSL_INTERFACE_PACKING_PACKED)) {
> +         b->type = resize_block_array(b->type, b->array);
> +         b->var->type = b->type;
> +      }
>  
>        block_size.num_active_uniforms = 0;
> -      block_size.process(block_type, "");
> +      block_size.process(b->type->without_array(), "");
>  
> -      if (b->num_array_elements > 0) {
> -         num_blocks += b->num_array_elements;
> -         num_variables += b->num_array_elements
> -            * block_size.num_active_uniforms;
> +      if (b->array != NULL) {
> +         unsigned aoa_size = b->type->arrays_of_arrays_size();
> +         num_blocks += aoa_size;
> +         num_variables += aoa_size * block_size.num_active_uniforms;
>        } else {
>           num_blocks++;
>           num_variables += block_size.num_active_uniforms;
> @@ -281,50 +370,15 @@ link_uniform_blocks(void *mem_ctx,
>           (const struct link_uniform_block_active *) entry->data;
>        const glsl_type *block_type = b->type;
>  
> -      if (b->num_array_elements > 0) {
> -         const char *const name = block_type->fields.array->name;
> +      if (b->array != NULL) {
> +         unsigned binding_offset = 0;
> +         char *name = ralloc_strdup(NULL, block_type->without_array()->name);
> +         size_t name_length = strlen(name);
>  
>           assert(b->has_instance_name);
> -         for (unsigned j = 0; j < b->num_array_elements; j++) {
> -            blocks[i].Name = ralloc_asprintf(blocks, "%s[%u]", name,
> -                                             b->array_elements[j]);
> -            blocks[i].Uniforms = &variables[parcel.index];
> -
> -            /* The GL_ARB_shading_language_420pack spec says:
> -             *
> -             *     "If the binding identifier is used with a uniform block
> -             *     instanced as an array then the first element of the array
> -             *     takes the specified block binding and each subsequent
> -             *     element takes the next consecutive uniform block binding
> -             *     point."
> -             */
> -            blocks[i].Binding = (b->has_binding) ? b->binding + j : 0;
> -
> -            blocks[i].UniformBufferSize = 0;
> -            blocks[i]._Packing =
> -               gl_uniform_block_packing(block_type->interface_packing);
> -
> -            parcel.process(block_type->fields.array,
> -                           blocks[i].Name);
> -
> -            blocks[i].UniformBufferSize = parcel.buffer_size;
> -
> -            /* Check SSBO size is lower than maximum supported size for SSBO */
> -            if (b->is_shader_storage &&
> -                parcel.buffer_size > ctx->Const.MaxShaderStorageBlockSize) {
> -               linker_error(prog, "shader storage block `%s' has size %d, "
> -                            "which is larger than than the maximum allowed (%d)",
> -                            block_type->name,
> -                            parcel.buffer_size,
> -                            ctx->Const.MaxShaderStorageBlockSize);
> -            }
> -            blocks[i].NumUniforms =
> -               (unsigned)(ptrdiff_t)(&variables[parcel.index] - blocks[i].Uniforms);
> -
> -            blocks[i].IsShaderStorage = b->is_shader_storage;
> -
> -            i++;
> -         }
> +         process_block_array(b->array, &name, name_length, blocks, &parcel,
> +                             variables, b, &i, &binding_offset, ctx, prog);
> +         ralloc_free(name);
>        } else {
>           blocks[i].Name = ralloc_strdup(blocks, block_type->name);
>           blocks[i].Uniforms = &variables[parcel.index];
> 


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