URL: http://llvm.org/
License: NCSA, MIT, GPLv2, others
License File: LICENSE

The files src/cxx_extractor_preprocessor_utils{.h, .cc} contain code from
  PreprocessorTracker.cpp from the modularize project in clang-tools-extra.
  We have modified this code by adding a visited set to the
  getMacroExpandedString function and sanity checks to getSourceString.

Description:
LLVM is an industrial strength optimizer and code generator supporting multiple
architectures, built as re-usable libraries, and providing both static and JIT
compilation models.