[Mesa-dev] [PATCH v3 (part1) 26/26] glsl: Lower shader storage buffer object loads to GLSL IR instrinsics

[Jordan Justen]

Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>

On 2015-07-10 03:13:45, Iago Toral Quiroga wrote:
> From: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
> 
> Extend the existing lower_ubo_reference pass to also detect SSBO loads
> and lower them to __intrinsic_load_ssbo intrinsics.
> 
> Signed-off-by: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
> ---
>  src/glsl/lower_ubo_reference.cpp | 73 +++++++++++++++++++++++++++++++++++-----
>  1 file changed, 65 insertions(+), 8 deletions(-)
> 
> diff --git a/src/glsl/lower_ubo_reference.cpp b/src/glsl/lower_ubo_reference.cpp
> index 460b490..822b723 100644
> --- a/src/glsl/lower_ubo_reference.cpp
> +++ b/src/glsl/lower_ubo_reference.cpp
> @@ -150,7 +150,8 @@ public:
>                                  int *matrix_columns);
>     ir_expression *ubo_load(const struct glsl_type *type,
>                            ir_rvalue *offset);
> -
> +   ir_call *ssbo_load(const struct glsl_type *type,
> +                      ir_rvalue *offset);
>  
>     void check_for_ssbo_write(ir_assignment *ir);
>     void write_to_memory(ir_dereference *deref,
> @@ -170,6 +171,7 @@ public:
>     struct gl_uniform_buffer_variable *ubo_var;
>     ir_rvalue *uniform_block;
>     bool progress;
> +   bool is_shader_storage;
>  };
>  
>  /**
> @@ -266,6 +268,8 @@ lower_ubo_reference_visitor::setup_for_load_or_write(ir_variable *var,
>              this->uniform_block = index;
>           }
>  
> +         this->is_shader_storage = shader->UniformBlocks[i].IsShaderStorage;
> +
>           struct gl_uniform_block *block = &shader->UniformBlocks[i];
>  
>           this->ubo_var = var->is_interface_instance()
> @@ -415,7 +419,7 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
>     if (!var || !var->is_in_buffer_block())
>        return;
>  
> -   mem_ctx = ralloc_parent(*rvalue);
> +   mem_ctx = ralloc_parent(shader->ir);
>  
>     ir_rvalue *offset = NULL;
>     unsigned const_offset;
> @@ -512,6 +516,42 @@ lower_ubo_reference_visitor::ssbo_write(ir_rvalue *deref,
>     return new(mem_ctx) ir_call(sig, NULL, &call_params);
>  }
>  
> +ir_call *
> +lower_ubo_reference_visitor::ssbo_load(const struct glsl_type *type,
> +                                       ir_rvalue *offset)
> +{
> +   exec_list sig_params;
> +
> +   ir_variable *block_ref = new(mem_ctx)
> +      ir_variable(glsl_type::uint_type, "block_ref" , ir_var_function_in);
> +   sig_params.push_tail(block_ref);
> +
> +   ir_variable *offset_ref = new(mem_ctx)
> +      ir_variable(glsl_type::uint_type, "offset_ref" , ir_var_function_in);
> +   sig_params.push_tail(offset_ref);
> +
> +   ir_function_signature *sig =
> +      new(mem_ctx) ir_function_signature(type, shader_storage_buffer_object);
> +   assert(sig);
> +   sig->replace_parameters(&sig_params);
> +   sig->is_intrinsic = true;
> +
> +   ir_function *f = new(mem_ctx) ir_function("__intrinsic_load_ssbo");
> +   f->add_signature(sig);
> +
> +   ir_variable *result = new(mem_ctx)
> +      ir_variable(type, "ssbo_load_result", ir_var_temporary);
> +   base_ir->insert_before(result);
> +   ir_dereference_variable *deref_result = new(mem_ctx)
> +      ir_dereference_variable(result);
> +
> +   exec_list call_params;
> +   call_params.push_tail(this->uniform_block->clone(mem_ctx, NULL));
> +   call_params.push_tail(offset->clone(mem_ctx, NULL));
> +
> +   return new(mem_ctx) ir_call(sig, deref_result, &call_params);
> +}
> +
>  static inline int
>  writemask_for_size(unsigned n)
>  {
> @@ -610,9 +650,17 @@ lower_ubo_reference_visitor::emit_reads_or_writes(bool is_write,
>           add(base_offset, new(mem_ctx) ir_constant(deref_offset));
>        if (is_write)
>           base_ir->insert_after(ssbo_write(deref, offset, write_mask));
> -      else
> -         base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
> -                                       ubo_load(deref->type, offset)));
> +      else {
> +         if (!this->is_shader_storage) {
> +             base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
> +                                           ubo_load(deref->type, offset)));
> +         } else {
> +            ir_call *load_ssbo = ssbo_load(deref->type, offset);
> +            base_ir->insert_before(load_ssbo);
> +            ir_rvalue *value = load_ssbo->return_deref->as_rvalue()->clone(mem_ctx, NULL);
> +            base_ir->insert_before(assign(deref->clone(mem_ctx, NULL), value));
> +         }
> +      }
>     } else {
>        unsigned N = deref->type->is_double() ? 8 : 4;
>  
> @@ -640,9 +688,18 @@ lower_ubo_reference_visitor::emit_reads_or_writes(bool is_write,
>           if (is_write) {
>              base_ir->insert_after(ssbo_write(swizzle(deref, i, 1), chan_offset, 1));
>           } else {
> -            base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
> -                                          ubo_load(deref_type, chan_offset),
> -                                          (1U << i)));
> +            if (!this->is_shader_storage) {
> +               base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
> +                                             ubo_load(deref_type, chan_offset),
> +                                             (1U << i)));
> +            } else {
> +               ir_call *load_ssbo = ssbo_load(deref_type, chan_offset);
> +               base_ir->insert_before(load_ssbo);
> +               ir_rvalue *value = load_ssbo->return_deref->as_rvalue()->clone(mem_ctx, NULL);
> +               base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
> +                                             value,
> +                                             (1U << i)));
> +            }
>           }
>        }
>     }
> -- 
> 1.9.1
>