Propagate Linux Kernel ORC information read from the file to the whole
function CFG once the graph has been built. We have a choice to either
attach ORC state annotation to every instruction, or to the first
instruction in the basic block to conserve processing memory. I chose to
attach to every instruction under --print-orc option which is currently
on by default.
Depends on D155153, D154815
Reviewed By: Amir
Differential Revision: https://reviews.llvm.org/D155156
Read ORC (oops rewind capability) info used for unwinding the stack by
Linux Kernel. The info is stored in .orc_unwind and .orc_unwind_ip
sections. There is also a related .orc_lookup section that is being
populated by the kernel during runtime. Contents of the sections are
sorted for quicker lookup by a post-link objtool.
Unless we modify stack access instructions, we don't have to change ORC
info attributed to instructions in the binary. However, we need to
update instruction addresses and sort both sections based on the new
layout.
For pretty printing, we add "--print-orc" option that prints ORC info
next to instructions in code dumps.
Reviewed By: Amir
Differential Revision: https://reviews.llvm.org/D154815
Create LinuxKernelRewriter and move kernel-specific code to this class.
Depends on D154023
Reviewed By: Amir
Differential Revision: https://reviews.llvm.org/D154024
