Sketch out a DWARF parser.

This introduces a new library to LLVM: libDebugInfo. It will provide debug information
parsing to LLVM. Much of the design and some of the code is taken from the LLDB project.

It also contains an llvm-dwarfdump tool that can dump the abbrevs and DIEs from an
object file. It can be used to write tests for DWARF input and output easily.

llvm-svn: 139627
diff --git a/llvm/lib/CMakeLists.txt b/llvm/lib/CMakeLists.txt
index 80118f0..45fa443 100644
--- a/llvm/lib/CMakeLists.txt
+++ b/llvm/lib/CMakeLists.txt
@@ -9,6 +9,7 @@
 add_subdirectory(MC)
 add_subdirectory(CompilerDriver)
 add_subdirectory(Object)
+add_subdirectory(DebugInfo)
 add_subdirectory(ExecutionEngine)
 add_subdirectory(Target)
 add_subdirectory(AsmParser)