Sort tensor list by name for serialization

- Tensors are stored in an unordered_map from mlir::Value::hash_value
  to tensor name.
- Before serialization, sort the tensor list alphabetically by name
  so that tensors always appear in a determinstic (and logical) order.

Signed-off-by: Jared Smolens <jared.smolens@arm.com>
Change-Id: I21c0e2ec04b7520e6a753b8bf62572a702002d5b

1 files changed, 12 insertions, 3 deletions

diff --git a/src/TosaSerialize.cpp b/src/TosaSerialize.cpp
index 5699ffe..0557520 100644
--- a/src/TosaSerialize.cpp
+++ b/src/TosaSerialize.cpp
@@ -24,6 +24,7 @@
 #include "tosa_serialization_handler.h"
 #include <functional>
 #include <unordered_map>
+#include <map>
 
 // The namespace might be confusing here. We have mlir::tosa:: defined in MLIR
 // and tosa:: defined in serialization library
@@ -1510,9 +1511,17 @@ mlir::LogicalResult TosaSerializationBlockBuilder::BuildAllOpsInRegion(
     }
 
     // Build tensor
-    for (auto pair : tensor_map) {
-      ser_tensor = BuildTosaSerializationTensor(pair.first /* val */,
-                                                pair.second /* name */);
+
+    // The tensor_map is sorted by hashed mlir::Value types.
+    // For serialization, sort tensors alphabetically by name for a deterministic
+    // and human-friendly ordering.
+    std::map<std::string, mlir::Value> tensor_name_sort;
+    for (auto pair : tensor_map)
+      tensor_name_sort[pair.second] = pair.first;
+
+    for (auto pair : tensor_name_sort) {
+      ser_tensor = BuildTosaSerializationTensor(pair.second /* val */,
+                                                pair.first /* name */);
       if (!ser_tensor) {
         llvm::errs() << "ERROR: Failed to build TosaSerializationTensor\n";
         return mlir::failure();