[Mesa-stable] [PATCH] glsl: fix lowering of UBO references of named blocks

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

When a UBO reference has the form block_name.foo where block_name refers
to a block where the first member has a non-zero offset, the base offset
was incorrectly added to the reference.

Fixes an assertion triggered in debug builds by
GL45-CTS.enhanced_layouts.uniform_block_layout_qualifier_conflict. That test
doesn't properly check for correct execution in this case, so I am also
going to send out a piglit test.

Cc: 13.0 <mesa-stable at lists.freedesktop.org>
---
 src/compiler/glsl/lower_ubo_reference.cpp | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/compiler/glsl/lower_ubo_reference.cpp b/src/compiler/glsl/lower_ubo_reference.cpp
index 37134a9..eafa1dd 100644
--- a/src/compiler/glsl/lower_ubo_reference.cpp
+++ b/src/compiler/glsl/lower_ubo_reference.cpp
@@ -100,21 +100,20 @@ public:
 
    unsigned calculate_unsized_array_stride(ir_dereference *deref,
                                            enum glsl_interface_packing packing);
 
    ir_call *lower_ssbo_atomic_intrinsic(ir_call *ir);
    ir_call *check_for_ssbo_atomic_intrinsic(ir_call *ir);
    ir_visitor_status visit_enter(ir_call *ir);
 
    struct gl_linked_shader *shader;
    bool clamp_block_indices;
-   struct gl_uniform_buffer_variable *ubo_var;
    const struct glsl_struct_field *struct_field;
    ir_variable *variable;
    ir_rvalue *uniform_block;
    bool progress;
 };
 
 /**
  * Determine the name of the interface block field
  *
  * This is the name of the specific member as it would appear in the
@@ -301,31 +300,32 @@ lower_ubo_reference_visitor::setup_for_load_or_store(void *mem_ctx,
       if (strcmp(field_name, blocks[i]->Name) == 0) {
 
          ir_constant *index = new(mem_ctx) ir_constant(i);
 
          if (nonconst_block_index) {
             this->uniform_block = add(nonconst_block_index, index);
          } else {
             this->uniform_block = index;
          }
 
-         this->ubo_var = var->is_interface_instance()
-            ? &blocks[i]->Uniforms[0] : &blocks[i]->Uniforms[var->data.location];
+         if (var->is_interface_instance()) {
+            *const_offset = 0;
+         } else {
+            *const_offset = blocks[i]->Uniforms[var->data.location].Offset;
+         }
 
          break;
       }
    }
 
    assert(this->uniform_block);
 
-   *const_offset = ubo_var->Offset;
-
    this->struct_field = NULL;
    setup_buffer_access(mem_ctx, deref, offset, const_offset, row_major,
                        matrix_columns, &this->struct_field, packing);
 }
 
 void
 lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
 {
    if (!*rvalue)
       return;
-- 
2.7.4