dwarf: fixup x86 register mapping logic
dwarf: change the register context update to update in-place instead of copying
debug: always print the unwind error type
Some DWARF5 subprograms have non-contiguous instruction ranges. An example of such
a function is `puts` in Ubuntu's libc. This change fixes name lookups for functions that use
DW_AT_range in their DIE.
- Fix unwindFrame using the previous FDE row instead of the current one
- Handle unwinding through noreturn functions
- Add x86-linux getcontext
- Fixup x86_64-linux getcontext not restoring the fp env
- Fix start_addr filtering on x86-windows
- .eh_frame_hdr contains a binary-searchable data structure for finding an FDE. If present, we can use this
section to avoid having to parse the entire FDE/CIE list in the binary, instead only entries that are actually
required for unwinding are read.
- rework the inputs pc-relative pointer decoding to support both already-mapped sections as well as sections
mapped from a file
- store the VirtualMachine on UnwindContext so the allocations can be reused
DWARF 5 moves around some fields and adds a few new ones that can't be
parsed or ignored by our current DWARF 4 parser. This isn't a complete
implementation of DWARF 5, but this is enough to make stack traces
mostly work. Line numbers from C++ don't show up, but I know the info
is there. I think the answer is to iterate through .debug_line_str in
getLineNumberInfo, but I didn't want to fall into an even deeper rabbit
hole tonight.
