Add filter-rtags-warnings.py script.

2018-09-25  Martin Liska  <mliska@suse.cz>

	* filter-rtags-warnings.py: New file.

From-SVN: r264560

contrib/ChangeLog

@@ -1,3 +1,7 @@
+2018-09-25  Martin Liska  <mliska@suse.cz>
+
+	* filter-rtags-warnings.py: New file.
+
 2018-09-25  Martin Liska  <mliska@suse.cz>
 
 	PR middle-end/86078

contrib/filter-rtags-warnings.py

@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+#
+# Script to analyze warnings produced by rtags command (using LLVM):
+# rc --diagnose-all --synchronous-diagnostics --json
+#
+# This file is part of GCC.
+#
+# GCC is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation; either version 3, or (at your option) any later
+# version.
+#
+# GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.  */
+#
+#
+#
+
+import sys
+import json
+import argparse
+
+def skip_warning(filename, warning):
+    ignores = {
+            '': ['-Warray-bounds', '-Wmismatched-tags', 'gcc_gfc: -Wignored-attributes', '-Wchar-subscripts',
+                'string literal (potentially insecure): -Wformat-security', '-Wdeprecated-register',
+                '-Wvarargs', 'keyword is hidden by macro definition', "but the argument has type 'char *': -Wformat-pedantic",
+                '-Wnested-anon-types', 'qualifier in explicit instantiation of', 'attribute argument not supported: asm_fprintf'],
+            'insn-modes.c': ['-Wshift-count-overflow'],
+            'insn-emit.c': ['-Wtautological-compare'],
+            'insn-attrtab.c': ['-Wparentheses-equality'],
+            'gimple-match.c': ['-Wunused-', '-Wtautological-compare'],
+            'generic-match.c': ['-Wunused-', '-Wtautological-compare'],
+    }
+
+    message = warning['message']
+
+    if warning['type'] == 'fixit':
+        return True
+
+    for name, ignores in ignores.items():
+        for i in ignores:
+            if name in filename and i in message:
+                return True
+
+    return False
+
+parser = argparse.ArgumentParser()
+parser.add_argument('json_file', help = 'Rtags JSON file with diagnostics')
+parser.add_argument('-n', '--no-filter', action = 'store_true', help = 'No filter')
+
+args = parser.parse_args()
+
+data = json.load(open(args.json_file))
+file_warnings = data['checkStyle']
+
+total = 0
+for filename, warnings in file_warnings.items():
+    if warnings:
+        for w in warnings:
+            if args.no_filter or not skip_warning(filename, w):
+                total += 1
+                print('%s:%d:%d:%s' % (filename, w['line'], w['column'], w['message']))
+
+print('Total: %d' % total)