From fa44d9d5369378be47cc12fe407651d01992a2ea Mon Sep 17 00:00:00 2001
From: Teodor Tanasoaia <28601907+teoxoy@users.noreply.github.com>
Date: Mon, 11 Apr 2022 06:42:02 +0200
Subject: [PATCH] [glsl-in] error on a `matCx2` used with the std140 layout
 (#1806)

---
 src/front/glsl/error.rs  | 6 ++++++
 src/front/glsl/offset.rs | 8 ++++++++
 2 files changed, 14 insertions(+)

diff --git a/src/front/glsl/error.rs b/src/front/glsl/error.rs
index cd0577a6e8..e1418f1e5c 100644
--- a/src/front/glsl/error.rs
+++ b/src/front/glsl/error.rs
@@ -94,6 +94,12 @@ pub enum ErrorKind {
     /// prioritize work.
     #[error("Unknown layout qualifier: {0}")]
     UnknownLayoutQualifier(String),
+    /// Unsupported matrix of the form matCx2
+    ///
+    /// Our IR expects matrices of the form matCx2 to have a stride of 8 however
+    /// matrices in the std140 layout have a stride of at least 16
+    #[error("unsupported matrix of the form matCx2 in std140 block layout")]
+    UnsupportedMatrixTypeInStd140,
     /// A variable with the same name already exists in the current scope.
     #[cfg(feature = "glsl-validate")]
     #[error("Variable already declared: {0}")]
diff --git a/src/front/glsl/offset.rs b/src/front/glsl/offset.rs
index 56ee4ab144..9c89b5d2c3 100644
--- a/src/front/glsl/offset.rs
+++ b/src/front/glsl/offset.rs
@@ -121,6 +121,14 @@ pub fn calculate_offset(
                 align = align_up(align, 16);
             }
 
+            // See comment on the error kind
+            if StructLayout::Std140 == layout && rows == crate::VectorSize::Bi {
+                errors.push(Error {
+                    kind: ErrorKind::UnsupportedMatrixTypeInStd140,
+                    meta,
+                });
+            }
+
             (align, align * columns as u32)
         }
         TypeInner::Struct { ref members, .. } => {