[Mesa-dev] [PATCH 09/16] linker: Add padding after the last field of a structure

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

This causes the thing following the structure to be vec4-aligned.

Fixes gles3conform failures in:

ES3-CTS.shaders.uniform_block.random.nested_structs.2
ES3-CTS.shaders.uniform_block.random.all_shared_buffer.5

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
---
 src/glsl/glsl_types.cpp          | 10 ++++++++--
 src/glsl/link_uniform_blocks.cpp | 13 +++++++++++++
 src/glsl/link_uniforms.cpp       |  5 ++++-
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/src/glsl/glsl_types.cpp b/src/glsl/glsl_types.cpp
index 932c72b..01a84b1 100644
--- a/src/glsl/glsl_types.cpp
+++ b/src/glsl/glsl_types.cpp
@@ -934,14 +934,20 @@ glsl_type::std140_size(bool row_major) const
     */
    if (this->is_record()) {
       unsigned size = 0;
+      unsigned max_align = 0;
+
       for (unsigned i = 0; i < this->length; i++) {
 	 const struct glsl_type *field_type = this->fields.structure[i].type;
 	 unsigned align = field_type->std140_base_alignment(row_major);
 	 size = glsl_align(size, align);
 	 size += field_type->std140_size(row_major);
+
+         max_align = MAX2(align, max_align);
+
+         if (field_type->is_record() && (i + 1 < this->length))
+            size = glsl_align(size, 16);
       }
-      size = glsl_align(size,
-			this->fields.structure[0].type->std140_base_alignment(row_major));
+      size = glsl_align(size, max_align);
       return size;
    }
 
diff --git a/src/glsl/link_uniform_blocks.cpp b/src/glsl/link_uniform_blocks.cpp
index d1c7da4..8db5296 100644
--- a/src/glsl/link_uniform_blocks.cpp
+++ b/src/glsl/link_uniform_blocks.cpp
@@ -104,7 +104,20 @@ private:
 
       this->offset = glsl_align(this->offset, alignment);
       v->Offset = this->offset;
+
+      /* If this is the last field of a structure, apply rule #9.  The
+       * GL_ARB_uniform_buffer_object spec says:
+       *
+       *     "The structure may have padding at the end; the base offset of
+       *     the member following the sub-structure is rounded up to the next
+       *     multiple of the base alignment of the structure."
+       *
+       * last_field won't be set if this is the last field of a UBO that is
+       * not a named instance.
+       */
       this->offset += size;
+      if (last_field)
+         this->offset = glsl_align(this->offset, 16);
 
       /* From the GL_ARB_uniform_buffer_object spec:
        *
diff --git a/src/glsl/link_uniforms.cpp b/src/glsl/link_uniforms.cpp
index 6dd8de4..c88ecbd 100644
--- a/src/glsl/link_uniforms.cpp
+++ b/src/glsl/link_uniforms.cpp
@@ -512,7 +512,7 @@ private:
 
    virtual void visit_field(const glsl_type *type, const char *name,
                             bool row_major, const glsl_type *record_type,
-                            bool /* last_field */)
+                            bool last_field)
    {
       assert(!type->is_record_or_array_of());
       assert(!type->is_interface_or_array_of());
@@ -581,6 +581,9 @@ private:
 	 this->uniforms[id].offset = this->ubo_byte_offset;
 	 this->ubo_byte_offset += type->std140_size(ubo_row_major);
 
+         if (last_field)
+            this->ubo_byte_offset = glsl_align(this->ubo_byte_offset, 16);
+
 	 if (type->is_array()) {
 	    this->uniforms[id].array_stride =
 	       glsl_align(type->fields.array->std140_size(ubo_row_major), 16);
-- 
1.8.1.4