FROMLIST: glsl: fix a binding points assignment for ssbo/ubo arrays

This is needed to be in agreement with spec requirements:
KhronosGroup/OpenGL-API#46

Piers Daniell:
   "We discussed this in the OpenGL/ES working group meeting
    and agreed that eliminating unused elements from the interface
    block array is not desirable. There is no statement in the spec
    that this takes place and it would be highly implementation
    dependent if it happens. If the application has an "interface"
    in the shader they need to match up with the API it would be
    quite confusing to have the binding point get compacted.
    So the answer is no, the binding points aren't affected by
    unused elements in the interface block array."

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109532
Reported-By: Ilia Mirkin <[email protected]>
Signed-off-by: Andrii Simiklit <[email protected]>

TEST=[CTS 9.0r6} dEQP-GLES31.functional.ssbo.layout.random.all_per_block_buffers#18
(am from https://gitlab.freedesktop.org/mesa/mesa/merge_requests/332)
Signed-off-by: Kevin Strasser <[email protected]>

Author: asimiklit

src/compiler/glsl/link_uniform_block_active_visitor.cpp

@@ -103,6 +103,7 @@ process_arrays(void *mem_ctx, ir_dereference_array *ir,
       if (*ub_array_ptr == NULL) {
          *ub_array_ptr = rzalloc(mem_ctx, struct uniform_block_array_elements);
          (*ub_array_ptr)->ir = ir;
+         (*ub_array_ptr)->original_dim_size = block->type->length;
       }
 
       struct uniform_block_array_elements *ub_array = *ub_array_ptr;

src/compiler/glsl/link_uniform_block_active_visitor.h

@@ -32,6 +32,7 @@ struct uniform_block_array_elements {
    unsigned num_array_elements;
 
    ir_dereference_array *ir;
+   unsigned original_dim_size;
 
    struct uniform_block_array_elements *array;
 };

src/compiler/glsl/link_uniform_blocks.cpp

@@ -244,18 +244,21 @@ process_block_array(struct uniform_block_array_elements *ub_array, char **name,
    for (unsigned j = 0; j < ub_array->num_array_elements; j++) {
       size_t new_length = name_length;
 
+      unsigned int element_idx = ub_array->array_elements[j];
       /* Append the subscript to the current variable name */
-      ralloc_asprintf_rewrite_tail(name, &new_length, "[%u]",
-                                   ub_array->array_elements[j]);
+      ralloc_asprintf_rewrite_tail(name, &new_length, "[%u]", element_idx);
 
       if (ub_array->array) {
+         unsigned boffset = (*binding_offset) + (element_idx *
+                             ub_array->original_dim_size);
          process_block_array(ub_array->array, name, new_length, blocks,
                              parcel, variables, b, block_index,
-                             binding_offset, ctx, prog, first_index);
+                             &boffset, ctx, prog, first_index);
       } else {
+         unsigned boffset = (*binding_offset) + element_idx;
          process_block_array_leaf(*name, blocks,
                                   parcel, variables, b, block_index,
-                                  binding_offset, *block_index - first_index,
+                                  &boffset, *block_index - first_index,
                                   ctx, prog);
       }
    }
@@ -307,7 +310,6 @@ process_block_array_leaf(const char *name,
       (unsigned)(ptrdiff_t)(&variables[parcel->index] - blocks[i].Uniforms);
 
    *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