Print detailed info in check_gn_headers.py

build/check_gn_headers.py

Index: build/check_gn_headers.py
diff --git a/build/check_gn_headers.py b/build/check_gn_headers.py
index 9164de115554cdc3d2fa03df8f1369feb92fcc46..1db587a7d2ef2d403d0226281b28838a9721d379 100755
--- a/build/check_gn_headers.py
+++ b/build/check_gn_headers.py
@@ -24,7 +24,7 @@ SRC_DIR = os.path.abspath(
 DEPOT_TOOLS_DIR = os.path.join(SRC_DIR, 'third_party', 'depot_tools')
 
 
-def GetHeadersFromNinja(out_dir, q):
+def GetHeadersFromNinja(out_dir, skip_obj, q):
   """Return all the header files from ninja_deps"""
 
   def NinjaSource():
@@ -42,20 +42,21 @@ def GetHeadersFromNinja(out_dir, q):
 
   ans, err = set(), None
   try:
-    ans = ParseNinjaDepsOutput(NinjaSource(), out_dir)
+    ans = ParseNinjaDepsOutput(NinjaSource(), out_dir, skip_obj)
   except Exception as e:
     err = str(e)
   q.put((ans, err))
 
 
-def ParseNinjaDepsOutput(ninja_out, out_dir):
+def ParseNinjaDepsOutput(ninja_out, out_dir, skip_obj):
   """Parse ninja output and get the header files"""
-  all_headers = set()
+  all_headers = {}
 
   # Ninja always uses "/", even on Windows.
   prefix = '../../'
 
   is_valid = False
+  obj_file = ''
   for line in ninja_out:
     if line.startswith('    '):
       if not is_valid:
@@ -70,9 +71,12 @@ def ParseNinjaDepsOutput(ninja_out, out_dir):
           if f.startswith(out_dir) or f.startswith('out'):
             continue
           if not f.startswith('build'):
-            all_headers.add(f)
+            all_headers.setdefault(f, [])
+            if not skip_obj:
+              all_headers[f].append(obj_file)
     else:
       is_valid = line.endswith('(VALID)')
+      obj_file = line.split(':')[0]
 
   return all_headers
 
@@ -91,7 +95,7 @@ def GetHeadersFromGN(out_dir, q):
     # Do "gn gen" in a temp dir to prevent dirtying |out_dir|.
     gn_exe = 'gn.bat' if sys.platform == 'win32' else 'gn'
     subprocess.check_call([
-      os.path.join(DEPOT_TOOLS_DIR, gn_exe), 'gen', tmp, '--ide=json', '-q'])
+        os.path.join(DEPOT_TOOLS_DIR, gn_exe), 'gen', tmp, '--ide=json', '-q'])
     gn_json = json.load(open(os.path.join(tmp, 'project.json')))
     ans = ParseGNProjectJSON(gn_json, out_dir, tmp)
   except Exception as e:
@@ -190,6 +194,8 @@ def main():
   parser.add_argument('--whitelist', help='file containing whitelist')
   parser.add_argument('--skip-dirty-check', action='store_true',
                       help='skip checking whether the build is dirty')
+  parser.add_argument('--verbose', action='store_true',
+                      help='print more diagnostic info')
 
   args, _extras = parser.parse_known_args()
 
@@ -210,7 +216,7 @@ def main():
       parser.error(dirty_msg)
 
   d_q = Queue()
-  d_p = Process(target=GetHeadersFromNinja, args=(args.out_dir, d_q,))
+  d_p = Process(target=GetHeadersFromNinja, args=(args.out_dir, True, d_q,))
   d_p.start()
 
   gn_q = Queue()
@@ -223,7 +229,7 @@ def main():
 
   d, d_err = d_q.get()
   gn, gn_err = gn_q.get()
-  missing = d - gn
+  missing = set(d.keys()) - gn
   nonexisting = GetNonExistingFiles(gn)
 
   deps, deps_err = deps_q.get()
@@ -272,6 +278,22 @@ def main():
     for i in nonexisting:
       print i
 
+  if args.verbose:
+    # Only get detailed obj dependency here since it is slower.
+    GetHeadersFromNinja(args.out_dir, False, d_q)
+    d, d_err = d_q.get()
+    print '\nDetailed dependency info:'
+    for f in missing:
+      print f
+      for cc in d[f]:
+        print '  ', cc
+
+    print '\nMissing headers sorted by number of affected object files:'
+    count = {k: len(v) for (k, v) in d.iteritems()}
+    for f in sorted(count, key=count.get, reverse=True):
+      if f in missing:
+        print count[f], f
+
   return 1