Use Popen.communicate() to pass the symbol names to c++filt for demangling.

Passing symbol names via the command line parameters is tricky and requires additional escaping.
For example, it doesn't work with names starting with "-[".

BUG=none
R=timurrrr@chromium.org

Review URL: https://codereview.chromium.org/110443004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@240277 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 4 insertions, 5 deletions

diff --git a/tools/valgrind/test_suppressions.py b/tools/valgrind/test_suppressions.py
index 8a09fc7..d02d0c9 100755
--- a/tools/valgrind/test_suppressions.py
+++ b/tools/valgrind/test_suppressions.py
@@ -50,16 +50,15 @@ def ReadReportsFromFile(filename):
 def Demangle(names):
   """ Demangle a list of C++ symbols, return a list of human-readable symbols.
   """
+  # -n is not the default on Mac.
   args = ['c++filt', '-n']
-  args.extend(names)
   pipe = subprocess.Popen(args, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
-  stdout, _ = pipe.communicate()
+  stdout, _ = pipe.communicate(input='\n'.join(names))
   demangled = stdout.split("\n")
-
   # Each line ends with a newline, so the final entry of the split output
   # will always be ''.
-  assert len(demangled) == len(names) + 1
-  return demangled[:-1]
+  assert len(demangled) == len(names)
+  return demangled
 
 def GetSymbolsFromReport(report):
   """Extract all symbols from a suppression report."""