[Mesa-dev] [PATCH] glsl: avoid calling base_alignment when samplers are involved

[Ilia Mirkin]

Earlier commit 53bf7c8fd2e changed the logic to always call
base_alignment on structs. 1ec715ce8b12 hacked the function to return 0
for sampler fields, but didn't handle sampler arrays. Instead of
extending the hack, avoid calling base_alignment in the first place on
non-UBO uniforms.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89726
Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---

No regressions in a piglit run. This seems like the right thing to do
rather than further hacking base_alignment. I was in "fix it now!"
mode when I wrote the original logic, getting pretty frustrated at the
various UBO rules and the number of different places they were being
implemented inside mesa.

However I think that for uniforms, this is the one and only place. As
a side-benefit, this means that uniforms will be better packed in the
presence of structs. And this will hopefully fix a lot of
"glsl_align(0) might happen, waaaaa" errors from static checkers.

 src/glsl/glsl_types.cpp    | 9 ---------
 src/glsl/link_uniforms.cpp | 4 ++++
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/src/glsl/glsl_types.cpp b/src/glsl/glsl_types.cpp
index 38b37a6..be87b0a 100644
--- a/src/glsl/glsl_types.cpp
+++ b/src/glsl/glsl_types.cpp
@@ -1077,15 +1077,6 @@ glsl_type::std140_base_alignment(bool row_major) const
       return base_alignment;
    }
 
-   /* A sampler may never occur in a UBO (without bindless of some sort),
-    * however it is convenient to use this alignment function even with
-    * regular uniforms. This allows use of this function on uniform structs
-    * that contain samplers.
-    */
-   if (this->is_sampler()) {
-      return 0;
-   }
-
    assert(!"not reached");
    return -1;
 }
diff --git a/src/glsl/link_uniforms.cpp b/src/glsl/link_uniforms.cpp
index 799c74b..59adc29 100644
--- a/src/glsl/link_uniforms.cpp
+++ b/src/glsl/link_uniforms.cpp
@@ -547,6 +547,8 @@ private:
    virtual void enter_record(const glsl_type *type, const char *name,
                              bool row_major) {
       assert(type->is_record());
+      if (this->ubo_block_index == -1)
+         return;
       this->ubo_byte_offset = glsl_align(
             this->ubo_byte_offset, type->std140_base_alignment(row_major));
    }
@@ -554,6 +556,8 @@ private:
    virtual void leave_record(const glsl_type *type, const char *name,
                              bool row_major) {
       assert(type->is_record());
+      if (this->ubo_block_index == -1)
+         return;
       this->ubo_byte_offset = glsl_align(
             this->ubo_byte_offset, type->std140_base_alignment(row_major));
    }
-- 
2.0.5