tools/win/new_analyze_warnings/warning_diff.py

   1 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4 """
   5 This script takes two warning summary files and reports on the new warnings
   6 and the fixed warnings. The warning summaries are created by
   7 warnings_by_type.py.
   8
   9 A warning is identified by the source file and the warning text, without the
  10 Lines component or any line 'xxx' references within the warning.
  11 All warnings with the same signature are grouped together (duplicates are
  12 assumed to have been removed already).
  13
  14 If a file contains multiple warnings with the same signature then a report
  15 will be generated for each warning when the warning count changes.
  16 """
  17
  18 import sys
  19 import re
  20
  21 # Some sample warnings:
  22 # sctp_bsd_addr.c(182) : warning C28125: The function
  23 # 'InitializeCriticalSection' must be called from within a try/except block:
  24 #  The requirement might be conditional.
  25 # exception_handler.cc(813) : warning C6387: 'child_thread_handle' could be '0':
  26 #  this does not adhere to the specification for the function 'CloseHandle'. :
  27 # Lines: 773, 774, 775, 776, 777, 784, 802, 804, 809, 813
  28 # unistr.cpp(1823) : warning C28193: 'temporary value' holds a value that must
  29 # be examined.: Lines: 1823, 1824
  30 # Note "line '1428'" in this warning, and 'count went from 3 to 2':
  31 # scheduler.cc(1452) : warning C6246: Local declaration of 'node' hides
  32 # declaration of the same name in outer scope. For additional information, see
  33 # previous declaration at line '1428' of 'scheduler.cc'.: count went from 3 to 2
  34 # Note "line 454" in this warning:
  35 # gurl.cc(449) : warning C28112: A variable (empty_gurl) which is accessed via
  36 # an Interlocked function must always be accessed via an Interlocked function.
  37 # See line 454:  It is not always safe to access a variable which is accessed
  38 # via the Interlocked* family of functions in any other way.
  39
  40
  41 warningsToIgnore = [
  42   # We assume that memory allocations never fail
  43   "C6255", # _alloca indicates failure by raising a stack overflow exception.
  44   "C6308", # 'realloc' might return null pointer, leaking memory
  45   "C6387", # Param could be '0': this does not adhere to the specification for
  46   # the function
  47   # I have yet to see errors caused by passing 'char' to isspace and friends
  48   "C6330", # 'char' passed as _Param_(1) when 'unsigned char' is required
  49   # This warning needs to be in clang to make it effective
  50   "C6262", # Function uses too much stack
  51   # Triggers on isnan, isinf, and template metaprogramming.
  52   "C6334", # sizeof operator applied to an expression with an operator might
  53   # yield unexpected results:
  54   ]
  55
  56 warningRe = re.compile(r"(.*)\(\d+\) : warning (C\d{4,5}): (.*)")
  57 warningRefLine = re.compile(r"(.*line ')\d+('.*)")
  58 warningRefLine2 = re.compile(r"(.*line )\d+(:.*)")
  59
  60 def RemoveExtraneous(line):
  61   """
  62   Remove extraneous data such as the optional 'Lines:' block at the end of some
  63   warnings, and line ending characters.
  64   This ensures better matching and makes for less cluttered results.
  65   """
  66   linesOffset = line.find(": Lines:")
  67   if linesOffset >= 0:
  68     line = line[:linesOffset]
  69   return line.strip()
  70
  71
  72
  73 def SummarizeWarnings(filename):
  74   """
  75   This function reads the file and looks for warning messages. It creates a
  76   dictionary with the keys being the filename, warning number, and warning text,
  77   and returns this.
  78   The warning summary at the end is ignored because it doesn't match the regex
  79   due to the 'C' being stripped from the warnings, for just this purpose.
  80   """
  81   warnings = {}
  82   for line in open(filename).readlines():
  83     line = line.replace(r"\chromium\src", r"\analyze_chromium\src")
  84     line = line.replace(r"\chromium2\src", r"\analyze_chromium\src")
  85     line = RemoveExtraneous(line)
  86     match = warningRe.match(line)
  87     if match:
  88       file, warningNumber, description = match.groups()
  89       ignore = False
  90       if warningNumber in warningsToIgnore:
  91         ignore = True
  92       glesTest = "gles2_implementation_unittest"
  93       if warningNumber == "C6001" and line.count(glesTest) > 0:
  94         ignore = True  # Many spurious warnings of this form
  95       if not ignore:
  96         # See if the description contains line numbers, so that we can
  97         # remove them.
  98         matchLine = warningRefLine.match(description)
  99         if not matchLine:
 100           matchLine = warningRefLine2.match(description)
 101         if matchLine:
 102           # Replace referenced line numbers with #undef so that they don't cause
 103           # mismatches.
 104           description = "#undef".join(matchLine.groups())
 105         # Look for "the readable size is " and "the writable size is " because
 106         # these are often followed by sizes that vary in uninteresting ways,
 107         # especially between 32-bit and 64-bit builds.
 108         readableText = "the readable size is "
 109         writableText = "the writable size is "
 110         if description.find(readableText) >= 0:
 111           description = description[:description.find(readableText)]
 112         if description.find(writableText) >= 0:
 113           description = description[:description.find(writableText)]
 114
 115         key = (file, warningNumber, description)
 116         if not key in warnings:
 117           warnings[key] = []
 118         warnings[key].append(line.strip())
 119   return warnings
 120
 121
 122
 123 def PrintAdditions(oldResults, newResults, message, invert):
 124   results = []
 125   for key in newResults.keys():
 126     if oldResults.has_key(key):
 127       # Check to see if the warning count has changed
 128       old = oldResults[key]
 129       new = newResults[key]
 130       if len(new) > len(old):
 131         # If the warning count has increased then we don't know which ones are
 132         # new. Sigh... Report the new ones, up to some maximum:
 133         for warning in newResults[key]:
 134           if invert:
 135             results.append(warning + ": count went from %d to %d" % \
 136                 (len(newResults[key]), len(oldResults[key])))
 137           else:
 138             results.append(warning + ": count went from %d to %d" % \
 139                 (len(oldResults[key]), len(newResults[key])))
 140     else:
 141       # Totally new (or fixed) warning.
 142       results += newResults[key]
 143   # This sort is not perfect because it is alphabetic and it needs to switch to
 144   # numeric when it encounters digits. Later.
 145   results.sort()
 146   print "%s (%d total)" % (message, len(results))
 147   for line in results:
 148     print line
 149
 150
 151
 152 if len(sys.argv) < 3:
 153   print "Usage: %s oldsummary.txt newsummary.txt" % sys.argv[0]
 154   print "Prints the changes in warnings between two /analyze runs."
 155   sys.exit(0)
 156
 157 oldFilename = sys.argv[1]
 158 newFilename = sys.argv[2]
 159 oldResults = SummarizeWarnings(oldFilename)
 160 newResults = SummarizeWarnings(newFilename)
 161
 162 PrintAdditions(oldResults, newResults, "New warnings", False)
 163 print
 164 print
 165 PrintAdditions(newResults, oldResults, "Fixed warnings", True)