[Lldb-commits] [PATCH] D22266: Add "support" for DW_CFA_GNU_args_size to the unwinder

Jason Molenda via lldb-commits lldb-commits at lists.llvm.org
Tue Jul 12 23:00:47 PDT 2016

jasonmolenda accepted this revision.
jasonmolenda added a comment.
This revision is now accepted and ready to land.

This is fine - is there a binary using this?  I'd love to see the assembly code and a dump of the eh_frame CFI.

I googled around and didn't find much about DW_CFA_GNU_args_size but in the libunwind llvm sources (v. https://llvm.org/svn/llvm-project/libunwind/trunk/src/ ) it takes the uleb value and adjusts the stack pointer by that value??  I don't see why that wouldn't be encoded in the normal "CFA is sp + offset" type rule of eh_frame so it must not be quite that simple.  lldb will probably unwind incorrectly if code built frameless (not using a frame pointer register) is encountered.


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