The number one piece of feedback we've heard from Windows users of Clang is that they want to be able to debug their programs in Visual Studio. More than that, though, there is a world of Windows tools, such as profilers, post-mortem crash analyzers, self-debugging tools (dbghelp), and symbol servers, that makes it really worth implementing CodeView support in LLVM. Since the last dev meeting, we've been hard at work studying the format and slowly adding support for it to LLVM. This talk will give an overview of the format, and then go back and focus on the aspects that most impacted our design decisions in Clang and LLVM. As others in the community have discovered while working on LTO, LLDB, modules, and llvm-dsymutil, type information can often end up being the dominating factor in the performance of the toolchain. CodeView has some interesting design choices for solving that problem that I will share. I will close by talking about where we want to go in the future, and how we will eventually use LLD to package our CodeView into a PDB file.
