Mesa (master): glsl: fix GL_BUFFER_DATA_SIZE value for shader storage blocks with unsize arrays

[Samuel Iglesias Gonsálvez]

Module: Mesa
Branch: master
Commit: 85f1f0441326ef3f49a4edeac474599db471ef7f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=85f1f0441326ef3f49a4edeac474599db471ef7f

Author: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
Date:   Thu Oct 22 10:07:54 2015 +0200

glsl: fix GL_BUFFER_DATA_SIZE value for shader storage blocks with unsize arrays

>From ARB_program_interface_query:

"For the property of BUFFER_DATA_SIZE, then the implementation-dependent
 minimum total buffer object size, in basic machine units, required to hold
 all active variables associated with an active uniform block, shader
 storage block, or atomic counter buffer is written to <params>.  If the
 final member of an active shader storage block is array with no declared
 size, the minimum buffer size is computed assuming the array was declared
 as an array with one element."

Fixes the following dEQP-GLES31 tests:

dEQP-GLES31.functional.program_interface_query.shader_storage_block.buffer_data_size.named_block
dEQP-GLES31.functional.program_interface_query.shader_storage_block.buffer_data_size.unnamed_block
dEQP-GLES31.functional.program_interface_query.shader_storage_block.buffer_data_size.block_array

v2:
- Fix comment's indentation and explain that the parser already
  checked that unsized array is in last element of a shader
  storage block (Iago).
- Add assert (Iago).

Signed-off-by: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral at igalia.com>

---

 src/glsl/link_uniform_blocks.cpp |   22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/glsl/link_uniform_blocks.cpp b/src/glsl/link_uniform_blocks.cpp
index 5285d8d..d5d30bb 100644
--- a/src/glsl/link_uniform_blocks.cpp
+++ b/src/glsl/link_uniform_blocks.cpp
@@ -100,7 +100,7 @@ private:
    virtual void visit_field(const glsl_type *type, const char *name,
                             bool row_major, const glsl_type *,
                             const unsigned packing,
-                            bool /* last_field */)
+                            bool last_field)
    {
       assert(this->index < this->num_variables);
 
@@ -131,12 +131,28 @@ private:
       unsigned alignment = 0;
       unsigned size = 0;
 
+      /* From ARB_program_interface_query:
+       *
+       *     "If the final member of an active shader storage block is array
+       *      with no declared size, the minimum buffer size is computed
+       *      assuming the array was declared as an array with one element."
+       *
+       * For that reason, we use the base type of the unsized array to calculate
+       * its size. We don't need to check if the unsized array is the last member
+       * of a shader storage block (that check was already done by the parser).
+       */
+      const glsl_type *type_for_size = type;
+      if (type->is_unsized_array()) {
+         assert(last_field);
+         type_for_size = type->without_array();
+      }
+
       if (packing == GLSL_INTERFACE_PACKING_STD430) {
          alignment = type->std430_base_alignment(v->RowMajor);
-         size = type->std430_size(v->RowMajor);
+         size = type_for_size->std430_size(v->RowMajor);
       } else {
          alignment = type->std140_base_alignment(v->RowMajor);
-         size = type->std140_size(v->RowMajor);
+         size = type_for_size->std140_size(v->RowMajor);
       }
 
       this->offset = glsl_align(this->offset, alignment);