To clarify, #1 is saying to re-implement the API **in LLVM** so that LLDB transparently just works with no code changes. While #2 is saying to re-implement the plugin **in LLDB** to not use that API at all, and instead use the low-level API that parses records directly from the file.
On Tue, Oct 2, 2018 at 1:57 PM Zachary Turner <ztur...@google.com> wrote: > Currently our PDBASTParser and SymbolFilePDB can only work on Windows > because it relies on a builtin Windows library. > > In LLVM now we have full ability to read, parse, and interpret the > contents of PDB files at the byte level. There are two approaches to > getting this working in LLDB. > > 1) Re-implement all the APIs that LLDB is currently using in terms of > LLVM's native PDB parsing code. This would be the most transparent > solution from LLDB's point of view. > > 2) Re-implement the code in LLDB in terms of LLVM's low level PDB API. > > Originally there was someone working on #1, but I'm having second thoughts > about whether that is the best approach. The API in question has a log of > "architecture overhead" associated with it, both in terms of runtime cost > and implementation cost. It essentially aims to be a one-size-fits-all > abstraction over every possible use case for consuming debug info. So in > order to implement #1 you end up doing a lot of work that isn't strictly > necessary for LLDB's use case. Mechanical code only necessary to fit with > the design. > > But LLDB doesn't exactly need all of that. So I started thinking about > #2. Instead of spending weeks / months completing this API, then finding > all the places where the APIs differ semantically in subtle ways that > require changing the user code, we can just get rid of the existing > implementation and re-implement existing functionality in terms of the low > level PDB functionality of LLVM. > > Obviously, until it's at parity with the existing Windows-only > implementation, this would be done side-by-side so the existing > implementation would stay and still be the default. We could putt he new > implementation behind an environment variable or something for testing > purposes (and use it unconditionally on non-Windows). > > > I'm going to experiment with this by implementing a SymbolFilePDBNative > plugin, but I want to see if anyone has strong objections to this approach. >
_______________________________________________ lldb-dev mailing list lldb-dev@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
