scripts: gcc-wrapper: Use wrapper to check compiler warnings

Rather than telling gcc to make warnings as errors, and then hunting
down make rules to disable this, leave them as warnings, but invoke
gcc through a wrapper that checks the warnings against a whitelist.

The initial whitelist comes from the warnings in the current build,
all of which have been allowed through Make overrides.

Change-Id: I5e0b199f9803d072537eeb77cb38d91cc06e951b
Signed-off-by: David Brown <davidb@codeaurora.org>
[mattw@codeaurora.org: update allowed_warnings for msm-3.14]
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>

1 files changed, 97 insertions, 0 deletions

diff --git a/scripts/gcc-wrapper.py b/scripts/gcc-wrapper.py
new file mode 100755
index 000000000000..698a898e5ce6
--- /dev/null
+++ b/scripts/gcc-wrapper.py
@@ -0,0 +1,97 @@
+#! /usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright (c) 2011-2014, The Linux Foundation. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#     * Redistributions of source code must retain the above copyright
+#       notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above copyright
+#       notice, this list of conditions and the following disclaimer in the
+#       documentation and/or other materials provided with the distribution.
+#     * Neither the name of The Linux Foundation nor
+#       the names of its contributors may be used to endorse or promote
+#       products derived from this software without specific prior written
+#       permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NON-INFRINGEMENT ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+# OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# Invoke gcc, looking for warnings, and causing a failure if there are
+# non-whitelisted warnings.
+
+import errno
+import re
+import os
+import sys
+import subprocess
+
+# Note that gcc uses unicode, which may depend on the locale.  TODO:
+# force LANG to be set to en_US.UTF-8 to get consistent warnings.
+
+allowed_warnings = set([
+    "return_address.c:63",
+    "clkdev.c:47",
+ ])
+
+# Capture the name of the object file, can find it.
+ofile = None
+
+warning_re = re.compile(r'''(.*/|)([^/]+\.[a-z]+:\d+):(\d+:)? warning:''')
+def interpret_warning(line):
+    """Decode the message from gcc.  The messages we care about have a filename, and a warning"""
+    line = line.rstrip('\n')
+    m = warning_re.match(line)
+    if m and m.group(2) not in allowed_warnings:
+        print "error, forbidden warning:", m.group(2)
+
+        # If there is a warning, remove any object if it exists.
+        if ofile:
+            try:
+                os.remove(ofile)
+            except OSError:
+                pass
+        sys.exit(1)
+
+def run_gcc():
+    args = sys.argv[1:]
+    # Look for -o
+    try:
+        i = args.index('-o')
+        global ofile
+        ofile = args[i+1]
+    except (ValueError, IndexError):
+        pass
+
+    compiler = sys.argv[0]
+
+    try:
+        proc = subprocess.Popen(args, stderr=subprocess.PIPE)
+        for line in proc.stderr:
+            print line,
+            interpret_warning(line)
+
+        result = proc.wait()
+    except OSError as e:
+        result = e.errno
+        if result == errno.ENOENT:
+            print args[0] + ':',e.strerror
+            print 'Is your PATH set correctly?'
+        else:
+            print ' '.join(args), str(e)
+
+    return result
+
+if __name__ == '__main__':
+    status = run_gcc()
+    sys.exit(status)