new loplugin virtualdown

Look for virtual methods where we can push their definition "down" i.e.
the base virtual method does not need to exist at all, because all the
call-sites are calling the more specific overrides.

Change-Id: Ib8e82637bfb6bc2a06df45de0e289d27344fb3ab
Reviewed-on: https://gerrit.libreoffice.org/51986
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 49 insertions, 0 deletions

diff --git a/compilerplugins/clang/virtualdown.py b/compilerplugins/clang/virtualdown.py
new file mode 100755
index 000000000000..f2121c07a29b
--- /dev/null
+++ b/compilerplugins/clang/virtualdown.py
@@ -0,0 +1,49 @@
+#!/usr/bin/python
+
+import io
+import re
+import sys
+
+definitionSet = set()
+definitionToSourceLocationMap = dict()
+callSet = set()
+
+
+with io.open("loplugin.virtualdown.log", "rb", buffering=1024*1024) as txt:
+    for line in txt:
+        tokens = line.strip().split("\t")
+        if tokens[0] == "definition:":
+            fullMethodName = tokens[1]
+            sourceLocation = tokens[2]
+            definitionSet.add(fullMethodName)
+            definitionToSourceLocationMap[fullMethodName] = sourceLocation
+        elif tokens[0] == "call:":
+            fullMethodName = tokens[1]
+            callSet.add(fullMethodName)
+            
+unnecessaryVirtualSet = set()
+
+for clazz in (definitionSet - callSet):
+#    if clazz.startswith("canvas::"): continue
+#    if clazz == "basegfx::unotools::UnoPolyPolygon::void-modifying()const": continue
+    # ignore external code
+    if definitionToSourceLocationMap[clazz].startswith("external/"): continue
+
+    unnecessaryVirtualSet.add((clazz,definitionToSourceLocationMap[clazz] ))
+
+
+# sort the results using a "natural order" so sequences like [item1,item2,item10] sort nicely
+def natural_sort_key(s, _nsre=re.compile('([0-9]+)')):
+    return [int(text) if text.isdigit() else text.lower()
+            for text in re.split(_nsre, s)]
+
+# sort results by name and line number
+tmp1list = sorted(unnecessaryVirtualSet, key=lambda v: natural_sort_key(v[1]))
+
+with open("compilerplugins/clang/virtualdown.results", "wt") as f:
+    for t in tmp1list:
+        f.write( t[1] + "\n" )
+        f.write( "    " + t[0] + "\n" )
+    # add an empty line at the end to make it easier for the removevirtuals plugin to mmap() the output file
+    f.write("\n")
+