[Mesa-dev] [PATCH 14/36] glsl ubo/ssbo: Use enum to track current buffer access type

[Jordan Justen]

On 2015-11-16 03:06:37, Iago Toral wrote:
> On Sat, 2015-11-14 at 13:43 -0800, Jordan Justen wrote:
> > Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
> > Cc: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
> > Cc: Iago Toral Quiroga <itoral at igalia.com>
> > ---
> >  src/glsl/lower_ubo_reference.cpp | 26 +++++++++++++++++++++-----
> >  1 file changed, 21 insertions(+), 5 deletions(-)
> > 
> > diff --git a/src/glsl/lower_ubo_reference.cpp b/src/glsl/lower_ubo_reference.cpp
> > index b74aa3d..41012db 100644
> > --- a/src/glsl/lower_ubo_reference.cpp
> > +++ b/src/glsl/lower_ubo_reference.cpp
> > @@ -162,6 +162,14 @@ public:
> >     ir_call *ssbo_store(ir_rvalue *deref, ir_rvalue *offset,
> >                         unsigned write_mask);
> >  
> > +   enum {
> > +      ubo_load_access,
> > +      ssbo_load_access,
> > +      ssbo_store_access,
> > +      ssbo_get_array_length,
> 
> ssbo_get_array_length misses that is for "unsized" arrays and does not
> include the "access" prefix that the other enum values have, which makes
> it a bit inconsistent. How about we name this
> 'ssbo_unsized_array_length_access'? or maybe 'ssbo_unsized_array_access'
> if we think the former is too long.
> 
> > +      ssbo_atomic_access,
> > +   } buffer_access_type;
> > +
> >     void emit_access(bool is_write, ir_dereference *deref,
> >                      ir_variable *base_offset, unsigned int deref_offset,
> >                      bool row_major, int matrix_columns,
> > @@ -189,7 +197,6 @@ public:
> >     struct gl_uniform_buffer_variable *ubo_var;
> >     ir_rvalue *uniform_block;
> >     bool progress;
> > -   bool is_shader_storage;
> >  };
> >  
> >  /**
> > @@ -339,10 +346,9 @@ lower_ubo_reference_visitor::setup_for_load_or_store(ir_variable *var,
> >                             deref, &nonconst_block_index);
> >  
> >     /* Locate the block by interface name */
> > -   this->is_shader_storage = var->is_in_shader_storage_block();
> >     unsigned num_blocks;
> >     struct gl_uniform_block **blocks;
> > -   if (this->is_shader_storage) {
> > +   if (buffer_access_type != ubo_load_access) {
> 
> I think this file generally uses 'this->' to refer to class members (or
> at least this function does), so maybe we should keep that for
> consistency. The same in the other places where you use
> buffer_access_type.

I don't really agree with this, but I went ahead and changed it.

> That said, right now it seems that we only ever use buffer_access_type
> here and you always assign its value right before calling
> setup_for_load_or_store() so maybe it is better to just make it a
> function parameter instead of a class member? setup_for_load_or_store()
> already has a large number of parameters, so I am not super happy about
> the idea, but it looks more natural to me. What do you think?

This function is going to move to
lower_buffer_access::setup_buffer_access. This class doesn't know
about enum of buffer_access_type, since that remains part of the
lower_ubo_reference_visitor class.

Therefore, I think we need to keep it as a member variable, so the
insert_buffer_access virtual function implementation in
lower_ubo_reference_visitor can make use of it.

-Jordan

> 
> >        num_blocks = shader->NumShaderStorageBlocks;
> >        blocks = shader->ShaderStorageBlocks;
> >     } else {
> > @@ -552,6 +558,10 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
> >     int matrix_columns;
> >     unsigned packing = var->get_interface_type()->interface_packing;
> >  
> > +   buffer_access_type =
> > +      var->is_in_shader_storage_block() ?
> > +      ssbo_load_access : ubo_load_access;
> > +
> >     /* Compute the offset to the start if the dereference as well as other
> >      * information we need to configure the write
> >      */
> > @@ -795,7 +805,7 @@ lower_ubo_reference_visitor::emit_access(bool is_write,
> >        if (is_write)
> >           base_ir->insert_after(ssbo_store(deref, offset, write_mask));
> >        else {
> > -         if (!this->is_shader_storage) {
> > +         if (buffer_access_type == ubo_load_access) {
> >               base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
> >                                             ubo_load(deref->type, offset)));
> >           } else {
> > @@ -862,7 +872,7 @@ lower_ubo_reference_visitor::emit_access(bool is_write,
> >  
> >              base_ir->insert_after(ssbo_store(swizzle(deref, i, 1), chan_offset, 1));
> >           } else {
> > -            if (!this->is_shader_storage) {
> > +            if (buffer_access_type == ubo_load_access) {
> >                 base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
> >                                               ubo_load(deref_type, chan_offset),
> >                                               (1U << i)));
> > @@ -891,6 +901,8 @@ lower_ubo_reference_visitor::write_to_memory(ir_dereference *deref,
> >     int matrix_columns;
> >     unsigned packing = var->get_interface_type()->interface_packing;
> >  
> > +   buffer_access_type = ssbo_store_access;
> > +
> >     /* Compute the offset to the start if the dereference as well as other
> >      * information we need to configure the write
> >      */
> > @@ -1068,6 +1080,8 @@ lower_ubo_reference_visitor::process_ssbo_unsized_array_length(ir_rvalue **rvalu
> >     unsigned packing = var->get_interface_type()->interface_packing;
> >     int unsized_array_stride = calculate_unsized_array_stride(deref, packing);
> >  
> > +   buffer_access_type = ssbo_get_array_length;
> > +
> >     /* Compute the offset to the start if the dereference as well as other
> >      * information we need to calculate the length.
> >      */
> > @@ -1181,6 +1195,8 @@ lower_ubo_reference_visitor::lower_ssbo_atomic_intrinsic(ir_call *ir)
> >     int matrix_columns;
> >     unsigned packing = var->get_interface_type()->interface_packing;
> >  
> > +   buffer_access_type = ssbo_atomic_access;
> > +
> >     setup_for_load_or_store(var, deref,
> >                             &offset, &const_offset,
> >                             &row_major, &matrix_columns,
> 
>