tool to generate compile_commands.json for analysis servers

Change-Id: I51124edf583fd4b4f66176a28ff0ebe11b6340fa
Reviewed-on: https://dart-review.googlesource.com/c/86380
Auto-Submit: Daco Harkes <dacoharkes@google.com>
Reviewed-by: Samir Jindel <sjindel@google.com>

.gitignore

@@ -83,3 +83,4 @@ editor/util/testing/mac/Samples.suite/Results
 /outline.dill
 /generated/
 /crash_logs/
+compile_commands.json

tools/generate_compile_commands.py

@@ -0,0 +1,48 @@
+#!/usr/bin/python
+#
+# Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file
+# for details. All rights reserved. Use of this source code is governed by a
+# BSD-style license that can be found in the LICENSE file.
+
+import subprocess
+import json
+import utils
+
+### Python script to generate compile_commands.json and make it more useful.
+
+HOST_OS = utils.GuessOS()
+
+if not HOST_OS in ['linux', 'macos']:
+  print ("Generate compile_commands has not been ported to %s yet." % (HOST_OS))
+  exit
+
+if HOST_OS == 'linux':
+  ninja = 'ninja-linux64'
+  out_folder = ' out'
+if HOST_OS == 'macos':
+  ninja = 'ninja-mac'
+  out_folder = ' xcodebuild'
+
+subprocess.call("python tools/generate_buildfiles.py", shell=True)
+
+command_set = json.loads(
+  subprocess.check_output(
+    ninja + " -C " + out_folder + "/DebugX64 -t compdb cxx cc h", shell=True
+  )
+)
+
+commands = []
+for obj in command_set:
+  C = obj["command"]
+
+  # Skip precompiled mode, a lot of code is commented out in precompiled mode
+  if ("-DDART_PRECOMPILED_RUNTIME" in C):
+    continue
+
+  # Remove warnings
+  C = C.replace("-Werror", "")
+
+  obj["command"] = C
+  commands += [obj]
+
+json.dump(commands, open("compile_commands.json", "w"), indent=4)