gcovr consumes 100% CPU with gcc 4.9

[Michi Henning]

Since installing gcc 4.9, gcovr no longer works for me. (No problems with 4.8.) From my cmake build:

Processing file src/scopes/testing/InProcessBenchmark.cpp
Processing file src/scopes/testing/Benchmark.cpp
Processing file src/scopes/testing/OutOfProcessBenchmark.cpp
Processing file src/scopes/testing/ScopeMetadataBuilder.cpp
Processing file src/scopes/testing/Statistics.cpp
Writing directory view page.
Overall coverage rate:
  lines......: 2.8% (259 of 9367 lines)
  functions..: 7.8% (187 of 2405 functions)
[ 98%] Generating coverage XML report

At that point, the build hangs. Looking at gcovr with ps, I see:

/usr/bin/python /usr/bin/gcovr -x -r /home/michi/src/devel -e /usr/include -e /home/michi/src/devel/test/* -e /home/michi/src/devel/build/*

top shows gcovr consuming 100% CPU.

Interestingly enough, it seems that most (or even all) of the HTML output is actually generated regardless. When I interrupt the build, I get the following from Python:

Traceback (most recent call last):
  File "/usr/bin/gcovr", line 1828, in <module>
make[3]: *** Deleting file 'coverage.xml'
    datafiles = get_datafiles(options.root, options)
  File "/usr/bin/gcovr", line 377, in get_datafiles
    files = search_file(".*\.gc(da|no)$", dir)
  File "/usr/bin/gcovr", line 357, in search_file
    for root, dirs, files in link_walker(path):
  File "/usr/bin/gcovr", line 317, in link_walker
    yield os.path.abspath(os.path.realpath(root)), dirs, files
  File "/usr/lib/python2.7/posixpath.py", line 382, in realpath
    path, ok = _joinrealpath('', filename, {})
  File "/usr/lib/python2.7/posixpath.py", line 407, in _joinrealpath
CMakeFiles/coverage.dir/build.make:61: recipe for target 'coverage.xml' failed
    if not islink(newpath):
  File "/usr/lib/python2.7/posixpath.py", line 142, in islink
make[3]: *** [coverage.xml] Interrupt
    st = os.lstat(path)