PDB Generator Status

[siegfriedpammer]

See #1230 as well.

• stepping
• anonymous methods SequencePointBuilder: No sequence points generated for nested ILFunctions (i.e., lambdas) #1229
• async/yield state machines
• local variables (verify)
• find side-effect free instructions to simulate sequence points on braces and keywords. Add sequence points on opening/closing braces #1245
• PDB tests

[dgrunwald]

If everything is working optimally, debugging release binaries with generated PDB files will still have some limitations:

• If the assembly was originally built without debug info; it will lack a debug header and Visual Studio will never attempt to load any PDB file for it.
• If the assembly uses [assembly: Debuggable(DebuggableAttribute.DebuggingModes.IgnoreSymbolStoreSequencePoints)], stepping will be unreliable. The C# compiler emits this attribute by default in some release builds (depending on the debug options in use).
• In release builds, the C# compiler likes to optimize out local variables, using the IL evaluation stack instead. There is no way for PDB debug information to assign names to evaluation stack slots, so it will be impossible to view the values of such variables.