Add calls into LanguageRuntime when finding the unwind method to
use out of the 0th (currently executing) stack frame.
Allow for the LanguageRuntimes to indicate if this stack frames
should be treated like a zeroth-frame -- symbolication should be
done based on the saved pc address, not decremented like normal ABI
function calls.
Add methods to RegisterContext and StackFrame to get a pc value
suitable for symbolication, to reduce the number of places in lldb
where we decrement the saved pc values before symbolication.
<rdar://problem/70398009>
Differential Revision: https://reviews.llvm.org/D97644
Summary:
This is the only real unwinder, and things have been this way for quite
a long time. At this point, the class has accumulated so many features
it is unlikely that anyone will want to reimplement the whole thing.
The class is also fairly closely coupled (through UnwindPlans and
FuncUnwinders) with a lot of other lldb components that it is hard to
imagine a different unwinder implementation being substantially
different without reimplementing all of those.
The existing unwinding functionality is nonetheless fairly complex and
there is space for adding more structure to it, but I believe a more
worthwhile effort would be to take the existing UnwindLLDB class and try
to break it down and introduce extension/customization points, instead
of writing a brand new Unwind implementation.
Reviewers: jasonmolenda, JDevlieghere, xiaobai
Subscribers: mgorny, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D75848