From 46c472731f28ce5df4100e2e04cf5f6257b567c6 Mon Sep 17 00:00:00 2001
From: teoxoy <28601907+teoxoy@users.noreply.github.com>
Date: Wed, 20 Sep 2023 14:09:50 +0200
Subject: [PATCH] [msl-out] add min version checks for binding arrays

---
 src/back/msl/mod.rs    |  4 +++
 src/back/msl/writer.rs | 59 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/src/back/msl/mod.rs b/src/back/msl/mod.rs
index 7b32ce80d7..fc507b4ea4 100644
--- a/src/back/msl/mod.rs
+++ b/src/back/msl/mod.rs
@@ -137,6 +137,10 @@ pub enum Error {
     UnsupportedWriteableStorageTexture(crate::ShaderStage),
     #[error("can not use read-write storage textures prior to MSL 1.2")]
     UnsupportedRWStorageTexture,
+    #[error("array of '{0}' is not supported for target MSL version")]
+    UnsupportedArrayOf(String),
+    #[error("array of type '{0:?}' is not supported")]
+    UnsupportedArrayOfType(Handle<crate::Type>),
 }
 
 #[derive(Clone, Debug, PartialEq, thiserror::Error)]
diff --git a/src/back/msl/writer.rs b/src/back/msl/writer.rs
index c17e84216c..285dcc4e71 100644
--- a/src/back/msl/writer.rs
+++ b/src/back/msl/writer.rs
@@ -4010,6 +4010,65 @@ impl<W: Write> Writer<W> {
                     }
                 }
 
+                // Check min MSL version for binding arrays
+                match var.space {
+                    crate::AddressSpace::Handle => match module.types[var.ty].inner {
+                        crate::TypeInner::BindingArray { base, .. } => {
+                            match module.types[base].inner {
+                                crate::TypeInner::Sampler { .. } => {
+                                    if options.lang_version < (2, 0) {
+                                        return Err(Error::UnsupportedArrayOf(
+                                            "samplers".to_string(),
+                                        ));
+                                    }
+                                }
+                                crate::TypeInner::Image { class, .. } => match class {
+                                    crate::ImageClass::Sampled { .. }
+                                    | crate::ImageClass::Depth { .. }
+                                    | crate::ImageClass::Storage {
+                                        access: crate::StorageAccess::LOAD,
+                                        ..
+                                    } => {
+                                        // Array of textures since:
+                                        // - iOS: Metal 1.2 (check depends on https://github.com/gfx-rs/naga/issues/2164)
+                                        // - macOS: Metal 2
+
+                                        if options.lang_version < (2, 0) {
+                                            return Err(Error::UnsupportedArrayOf(
+                                                "textures".to_string(),
+                                            ));
+                                        }
+                                    }
+                                    crate::ImageClass::Storage {
+                                        access: crate::StorageAccess::STORE,
+                                        ..
+                                    } => {
+                                        // Array of write-only textures since:
+                                        // - iOS: Metal 2.2 (check depends on https://github.com/gfx-rs/naga/issues/2164)
+                                        // - macOS: Metal 2
+
+                                        if options.lang_version < (2, 0) {
+                                            return Err(Error::UnsupportedArrayOf(
+                                                "write-only textures".to_string(),
+                                            ));
+                                        }
+                                    }
+                                    crate::ImageClass::Storage { .. } => {
+                                        return Err(Error::UnsupportedArrayOf(
+                                            "read-write textures".to_string(),
+                                        ));
+                                    }
+                                },
+                                _ => {
+                                    return Err(Error::UnsupportedArrayOfType(base));
+                                }
+                            }
+                        }
+                        _ => {}
+                    },
+                    _ => {}
+                }
+
                 // the resolves have already been checked for `!fake_missing_bindings` case
                 let resolved = match var.space {
                     crate::AddressSpace::PushConstant => options.resolve_push_constants(ep).ok(),