Change verilog_kythe_extractor so it can be used for running Kythe ve…

…rification tests directly from the bazel rules. This enables us to add the verification tests to the continuous integration.

Issues #395

PiperOrigin-RevId: 334405499

verilog/tools/kythe/build_defs/BUILD

@@ -0,0 +1,9 @@
+# Copyright 2020 Google LLC.
+# SPDX-License-Identifier: Apache-2.0
+
+package(
+    default_visibility = [
+        "//verilog/tools/kythe:__subpackages__",
+    ],
+    licenses = ["notice"],
+)

verilog/tools/kythe/testdata/BUILD

@@ -0,0 +1,2 @@
+# Copyright 2020 Google LLC.
+# SPDX-License-Identifier: Apache-2.0

verilog/tools/kythe/verilog_kythe_extractor.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <fstream>
 #include <iostream>
 #include <string>
 
@@ -33,6 +34,9 @@ ABSL_FLAG(bool, printextraction, false,
 ABSL_FLAG(bool, printkythefacts, false,
           "Whether or not to print the extracted kythe facts");
 
+ABSL_FLAG(std::string, output_path, "",
+          "File path where to write the extracted Kythe facts in JSON format.");
+
 static int ExtractOneFile(absl::string_view content,
                           absl::string_view filename) {
   int exit_status = 0;
@@ -60,6 +64,15 @@ static int ExtractOneFile(absl::string_view content,
     std::cout << verilog::kythe::KytheFactsPrinter(facts_tree) << std::endl;
   }
 
+  const std::string output_path = absl::GetFlag(FLAGS_output_path);
+  if (!output_path.empty()) {
+    std::ofstream f(output_path.c_str());
+    if (!f.good()) {
+      LOG(FATAL) << "Can't write to " << output_path;
+    }
+    f << verilog::kythe::KytheFactsPrinter(facts_tree) << std::endl;
+  }
+
   return exit_status;
 }