[Fix] fix the logic when comparing the runtime version strings.

PiperOrigin-RevId: 264948915

tensorflow/lite/toco/tflite/BUILD

@@ -146,6 +146,7 @@ cc_library(
         ":operator",
         "//tensorflow/lite/toco:model",
         "//tensorflow/lite/toco:tooling_util",
+        "@com_google_absl//absl/strings",
     ],
 )
 

tensorflow/lite/toco/tflite/op_version.cc

@@ -15,7 +15,10 @@ limitations under the License.
 #include "tensorflow/lite/toco/tflite/op_version.h"
 
 #include <cstring>
+#include <vector>
 
+#include "absl/strings/numbers.h"
+#include "absl/strings/str_split.h"
 #include "tensorflow/lite/toco/model.h"
 #include "tensorflow/lite/toco/tflite/operator.h"
 #include "tensorflow/lite/toco/tooling_util.h"
@@ -23,6 +26,23 @@ limitations under the License.
 namespace toco {
 namespace tflite {
 
+bool CompareVersion(const string& v1, const string& v2) {
+  const std::vector<string>& vec1 = absl::StrSplit(v1, '.');
+  const std::vector<string>& vec2 = absl::StrSplit(v2, '.');
+  int i = 0;
+  while (i < vec1.size() && i < vec2.size()) {
+    int v1_val, v2_val;
+    if (absl::SimpleAtoi(vec1[i], &v1_val) &&
+        absl::SimpleAtoi(vec2[i], &v2_val)) {
+      if (v1_val != v2_val) return v1_val < v2_val;
+    }
+    ++i;
+  }
+  // If there are remaining items in v2 not being compared, then v1 should
+  // precede v2.
+  return i < vec2.size();
+}
+
 string GetMinimumRuntimeVersionForModel(const Model& model) {
   // Use this as the placeholder string if a particular op is not yet included
   // in any Tensorflow's RC/Final release source package. Once that op is
@@ -193,7 +213,7 @@ string GetMinimumRuntimeVersionForModel(const Model& model) {
       // doesn't have a minimum runtime version associated, continue.
       continue;
     }
-    if (strcmp(model_min_version.c_str(), it->second.c_str()) < 0) {
+    if (CompareVersion(model_min_version, it->second)) {
       // Current min model runtime version should be bumped if we see a higher
       // op version.
       model_min_version = it->second;

tensorflow/lite/toco/tflite/op_version.h

@@ -20,6 +20,11 @@ limitations under the License.
 namespace toco {
 namespace tflite {
 
+// Returns true if the first version string precedes the second.
+// For example, '1.14' should precede '1.9', also '1.14.1' should precede
+// '1.14'. If two version string is equal, then false will be returned.
+bool CompareVersion(const string&, const string&);
+
 // Get the minimum TF Lite runtime required to run a model. Each built-in
 // operator in the model will have its own minimum requirement of a runtime, and
 // the model's minimum requirement of runtime is defined as the maximum of all

tensorflow/lite/toco/tflite/op_version_test.cc

@@ -134,6 +134,18 @@ TEST(OpVersionTest, MinimumVersionForMixedOpVersions) {
   EXPECT_EQ(GetMinimumRuntimeVersionForModel(model), "1.10.0");
 }
 
+TEST(OpVersionTest, CompareVersionString) {
+  EXPECT_TRUE(CompareVersion("1.9", "1.13"));
+  EXPECT_FALSE(CompareVersion("1.13", "1.13"));
+  EXPECT_TRUE(CompareVersion("1.14", "1.14.1"));
+  EXPECT_FALSE(CompareVersion("1.14.1", "1.14"));
+  EXPECT_FALSE(CompareVersion("1.14.1", "1.9"));
+  EXPECT_FALSE(CompareVersion("1.0.9", "1.0.8"));
+  EXPECT_FALSE(CompareVersion("2.1.0", "1.2.0"));
+  EXPECT_TRUE(CompareVersion("", "1.13"));
+  EXPECT_FALSE(CompareVersion("", ""));
+}
+
 }  // namespace
 }  // namespace tflite
 }  // namespace toco