[llvm-dev] How does LLDB locate the DWARF information stored inside MACH-O .o files produced by LLVM and LLD?

[David Blaikie via llvm-dev]

You'll need to go a bit further than the load commands - I don't know much
about MachO files, so I'm just reading:
https://lowlevelbits.org/parsing-mach-o-files/ and
https://samhuri.net/posts/2010/01/basics-of-the-mach-o-file-format - so
inside the section (described by the LC_SEGMENT_64) are probably a bunch of
sections, including debug info sections. Tools like llvm-objdump will show
you those (llvm-objdump -h), and also tools like llvm-dwarfdump can print
the contents of the debug info sections (those with names starting with
"__debug") in human-readable form.

On Thu, Aug 23, 2018 at 12:19 AM Andrew Kelley via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> When I make a simple test program and call abort() and use LLDB to debug
> it, it has address-to-line mapping. If I then delete the .o file and run
> LLDB again, it loses the address-to-line mapping. So there must be DWARF
> info, or otherwise address-to-line info in the .o file.
>
> I'm parsing the MACH-O executable, which has a LC_SYMTAB  entry, and one
> of the entries is the file path of the .o file. So I can find the file that
> way. Then I parse the MACH-O .o file, which also has the LC_SYMTAB, as well
> as an LC_SEGMENT_64 and LC_DATA_IN_CODE, and then finally a LC_DYSYMTAB.
> But I don't see where the address-to-line information is, or any DWARF
> information.
>
> Where is LLDB getting this address-to-line info?
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20180823/aab9f33f/attachment.html>