1 files changed, 18 insertions, 0 deletions
diff --git a/mlir/lib/Target/SPIRV/Serialization/Serializer.cpp b/mlir/lib/Target/SPIRV/Serialization/Serializer.cpp
index b88fbaa..29ed5a4 100644
--- a/mlir/lib/Target/SPIRV/Serialization/Serializer.cpp
+++ b/mlir/lib/Target/SPIRV/Serialization/Serializer.cpp
@@ -89,6 +89,22 @@ static bool isZeroValue(Attribute attr) {
   return false;
 }
 
+/// Move all functions declaration before functions definitions. In SPIR-V
+/// "declarations" are functions without a body and "definitions" functions
+/// with a body. This is stronger than necessary. It should be sufficient to
+/// ensure any declarations precede their uses and not all definitions, however
+/// this allows to avoid analysing every function in the module this way.
+static void moveFuncDeclarationsToTop(spirv::ModuleOp moduleOp) {
+  Block::OpListType &ops = moduleOp.getBody()->getOperations();
+  if (ops.empty())
+    return;
+  Operation &firstOp = ops.front();
+  for (Operation &op : llvm::drop_begin(ops))
+    if (auto funcOp = dyn_cast<spirv::FuncOp>(op))
+      if (funcOp.getBody().empty())
+        funcOp->moveBefore(&firstOp);
+}
+
 namespace mlir {
 namespace spirv {
 
@@ -119,6 +135,8 @@ LogicalResult Serializer::serialize() {
   processMemoryModel();
   processDebugInfo();
 
+  moveFuncDeclarationsToTop(module);
+
   // Iterate over the module body to serialize it. Assumptions are that there is
   // only one basic block in the moduleOp
   for (auto &op : *module.getBody()) {