Mesa (10.3): glsl: Make sure fields after small structs have correct padding
Emil Velikov
evelikov at kemper.freedesktop.org
Sat Sep 27 18:07:40 UTC 2014
Module: Mesa
Branch: 10.3
Commit: 9328440ef742e84092f0f418caebc4e1ea2a7c52
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=9328440ef742e84092f0f418caebc4e1ea2a7c52
Author: Ian Romanick <ian.d.romanick at intel.com>
Date: Mon Sep 8 12:23:39 2014 -0700
glsl: Make sure fields after small structs have correct padding
Previously the linker would correctly calculate the layout, but the
lower_ubo_reference pass would not apply correct alignment to fields
following small (less than 16-byte) nested structures.
Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83533
Cc: mesa-stable at lists.freedesktop.org
(cherry picked from commit 8e01c66da6c780601f941aa5b9939962c219fdbd)
---
src/glsl/lower_ubo_reference.cpp | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/src/glsl/lower_ubo_reference.cpp b/src/glsl/lower_ubo_reference.cpp
index 3cdfc04..4ae1aac 100644
--- a/src/glsl/lower_ubo_reference.cpp
+++ b/src/glsl/lower_ubo_reference.cpp
@@ -327,6 +327,15 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
const glsl_type *struct_type = deref_record->record->type;
unsigned intra_struct_offset = 0;
+ /* glsl_type::std140_base_alignment doesn't grok interfaces. Use
+ * 16-bytes for the alignment because that is the general minimum of
+ * std140.
+ */
+ const unsigned struct_alignment = struct_type->is_interface()
+ ? 16
+ : struct_type->std140_base_alignment(row_major);
+
+
for (unsigned int i = 0; i < struct_type->length; i++) {
const glsl_type *type = struct_type->fields.structure[i].type;
@@ -346,6 +355,19 @@ lower_ubo_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
deref_record->field) == 0)
break;
intra_struct_offset += type->std140_size(field_row_major);
+
+ /* If the field just examined was itself a structure, apply rule
+ * #9:
+ *
+ * "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."
+ */
+ if (type->without_array()->is_record()) {
+ intra_struct_offset = glsl_align(intra_struct_offset,
+ struct_alignment);
+
+ }
}
const_offset += intra_struct_offset;
More information about the mesa-commit
mailing list