Re: [RFC] [gdb/testsuite] Use dwarf assembly in gdb.dlang/dlang-start.exp

[Iain Buclaw via Gdb-patches <gdb-patches@sourceware.org>]

Excerpts from Tom de Vries via Gdb-patches's message of Februar 20, 2023 2:48 pm:
> For test-case gdb.dlang/dlang-start.exp, I run into:
> ...
> gdb compile failed, default_target_compile: Can't find gdc.
> ...
> 
> AFAICT, my distro has no support for gdc, but I'd like to have the test-case
> running and passing, so let's rewrite the test-case using dwarf assembly
> (though arguably, it's not a bad idea to have test-cases excercising
> actual compilers).
> 
> My distro does have a package providing dmd, so let's try out simple.d
> compiled with dmd, and investigate what the start command does.
> 

I'm pretty sure I'd get testsuite failures for not having Ada or Rust
installed either.  Shouldn't the testsuite just return UNSUPPORTED when
there's a missing dependency?

> AFAICT, gdb uses "D main" because the minimal symbol _Dmain:
> ...
> $ nm simple | grep 438448
> 0000000000438448 t
> 0000000000438448 W _Dmain
> ...
> is demangled into "D main":
> ...

Yes. If I try to second guess my thinking from 2016 or so. I believe it
was because "_Dmain" could come from any language, but having a space in
the identifier pretty much guarantees only a D compiler generated it.

Iain.