Re: GDB and debug fission

[Sterling Augustine via Gdb <gdb@sourceware.org>]

On Thu, Jan 7, 2021 at 5:25 PM Alexander Yermolovich via Gdb
<gdb@sourceware.org> wrote:
>
> Hello.
>
> For latest gdb to work with -gsplit-dwarf debug information generated by clang, either in split or single mode does it need gdb_index or pubnames?
> In normal case where debug information is part of executable gdb_index is nice to speed up startup time, and I think I read pubnames is not used, but with debug fission are either gdb_index or pubnames necessary?

For gdb to work with split-dwarf debug info, it needs a gdb_index.
That can be generated in several ways. Gdb can build one itself--there
is a script somewhere to add a gdb index.

But it is somewhat easier to have the linker you use generate
gdb_index for you (both gnu-ld and llvm's lld can do this). They do
this by reading the .gnu_pubnames section, so in some way, you need
both pubnames *and* an index.

So you would ordinarily use the following commands:

$(CC) $(normal_arguments) -ggnu-pubnames
$(LD)  $(normal_arguments) -Wl,--gdb-index