MSL: Consider that function/private variables can be block-like.

Handles a special case with array copies.
The implementation of this fix is not perfect, but should be good
enough for time being.

1 files changed, 14 insertions, 0 deletions

diff --git a/spirv_msl.cpp b/spirv_msl.cpp
index 1e4aa4bd..56794c32 100644
--- a/spirv_msl.cpp
+++ b/spirv_msl.cpp
@@ -8511,13 +8511,27 @@ void CompilerMSL::emit_array_copy(const string &lhs, uint32_t lhs_id, uint32_t r
 
 	// Special considerations for stage IO variables.
 	// If the variable is actually backed by non-user visible device storage, we use array templates for those.
+	//
+	// Another special consideration is given to thread local variables which happen to have Offset decorations
+	// applied to them. Block-like types do not use array templates, so we need to force POD path if we detect
+	// these scenarios. This check isn't perfect since it would be technically possible to mix and match these things,
+	// and for a fully correct solution we might have to track array template state through access chains as well,
+	// but for all reasonable use cases, this should suffice.
+	// This special case should also only apply to Function/Private storage classes.
+	// We should not check backing variable for temporaries.
 	auto *lhs_var = maybe_get_backing_variable(lhs_id);
 	if (lhs_var && lhs_storage == StorageClassStorageBuffer && storage_class_array_is_thread(lhs_var->storage))
 		lhs_is_array_template = true;
+	else if (lhs_var && (lhs_storage == StorageClassFunction || lhs_storage == StorageClassPrivate) &&
+	         type_is_block_like(get<SPIRType>(lhs_var->basetype)))
+		lhs_is_array_template = false;
 
 	auto *rhs_var = maybe_get_backing_variable(rhs_id);
 	if (rhs_var && rhs_storage == StorageClassStorageBuffer && storage_class_array_is_thread(rhs_var->storage))
 		rhs_is_array_template = true;
+	else if (rhs_var && (rhs_storage == StorageClassFunction || rhs_storage == StorageClassPrivate) &&
+	         type_is_block_like(get<SPIRType>(rhs_var->basetype)))
+		rhs_is_array_template = false;
 
 	// If threadgroup storage qualifiers are *not* used:
 	// Avoid spvCopy* wrapper functions; Otherwise, spvUnsafeArray<> template cannot be used with that storage qualifier.