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."

v2: - 'original_dim_size' field moved above to keep
      the struct packed better on 64-bit
    - added a comment for 'total_num_array_elements' field
    - fixed a binding point calculations for SSBOs array of arrays
          ( Ian Romanick <ian.d.romanick@intel.com> )
    - fixed binding point calculations for non-packed SSBOs

Fixes: 8cf1333 "glsl: link uniform block arrays of arrays"
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109532
Reported-By: Ilia Mirkin <imirkin@alum.mit.edu>
Tested-by: Fritz Koenig <frkoenig@google.com>
Signed-off-by: Andrii Simiklit <andrii.simiklit@globallogic.com>

TEST=[CTS 9.0_r8} 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 <kevin.strasser@intel.com>

Author: asimiklit

src/compiler/glsl/link_uniform_block_active_visitor.cpp

@@ -103,6 +103,8 @@ 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)->total_num_array_elements =
+                      ir->array->type->arrays_of_arrays_size();
       }
 
       struct uniform_block_array_elements *ub_array = *ub_array_ptr;
@@ -199,6 +201,7 @@ link_uniform_block_active_visitor::visit(ir_variable *var)
                                              (*ub_array)->array_elements,
                                              unsigned,
                                              (*ub_array)->num_array_elements);
+      (*ub_array)->total_num_array_elements = type->arrays_of_arrays_size();
 
       for (unsigned i = 0; i < (*ub_array)->num_array_elements; i++) {
          (*ub_array)->array_elements[i] = i;

src/compiler/glsl/link_uniform_block_active_visitor.h

@@ -30,6 +30,15 @@
 struct uniform_block_array_elements {
    unsigned *array_elements;
    unsigned num_array_elements;
+   /**
+    * Size of the array before array-trimming optimizations.
+    *
+    * Locations are only assigned to active array elements, but the location
+    * values are calculated as if all elements are active. The total number
+    * of elements in an array including the elements in arrays of arrays before
+    * inactive elements are removed is needed to be perform that calculation.
+    */
+   unsigned total_num_array_elements;
 
    ir_dereference_array *ir;
 

src/compiler/glsl/link_uniform_blocks.cpp

@@ -222,7 +222,7 @@ static void process_block_array_leaf(const char *name, gl_uniform_block *blocks,
                                      gl_uniform_buffer_variable *variables,
                                      const struct link_uniform_block_active *const b,
                                      unsigned *block_index,
-                                     unsigned *binding_offset,
+                                     unsigned binding_offset,
                                      unsigned linearized_index,
                                      struct gl_context *ctx,
                                      struct gl_shader_program *prog);
@@ -237,25 +237,28 @@ 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,
+                    unsigned *block_index, unsigned binding_offset,
                     struct gl_context *ctx, struct gl_shader_program *prog,
                     unsigned first_index)
 {
    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->array->total_num_array_elements);
          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);
       }
    }
@@ -266,7 +269,7 @@ process_block_array_leaf(const char *name,
                          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,
+                         unsigned *block_index, unsigned binding_offset,
                          unsigned linearized_index,
                          struct gl_context *ctx, struct gl_shader_program *prog)
 {
@@ -283,7 +286,7 @@ process_block_array_leaf(const char *name,
     *    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].Binding = (b->has_binding) ? b->binding + binding_offset : 0;
 
    blocks[i].UniformBufferSize = 0;
    blocks[i]._Packing = glsl_interface_packing(type->interface_packing);
@@ -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
@@ -370,20 +372,19 @@ create_buffer_blocks(void *mem_ctx, struct gl_context *ctx,
       if ((create_ubo_blocks && !b->is_shader_storage) ||
           (!create_ubo_blocks && b->is_shader_storage)) {
 
-         unsigned binding_offset = 0;
          if (b->array != NULL) {
             char *name = ralloc_strdup(NULL,
                                        block_type->without_array()->name);
             size_t name_length = strlen(name);
 
             assert(b->has_instance_name);
             process_block_array(b->array, &name, name_length, blocks, &parcel,
-                                variables, b, &i, &binding_offset, ctx, prog,
+                                variables, b, &i, 0, ctx, prog,
                                 i);
             ralloc_free(name);
          } else {
             process_block_array_leaf(block_type->name, blocks, &parcel,
-                                     variables, b, &i, &binding_offset,
+                                     variables, b, &i, 0,
                                      0, ctx, prog);
          }
       }