[lldb-dev] [Lldb-commits] [lldb] r360757 - Group forward declarations in one namespace lldb_private {}

[Pavel Labath via lldb-dev]

On 16/05/2019 01:10, Jim Ingham via lldb-dev wrote:
> When you add to them you are often adding some larger feature which would have required a rebuild anyway, and they go long times with no change...  I have never found the rebuild required when these files are touched to be a drag on my productivity.  And I really appreciate their convenience.
> 
> But thanks for your friendly advice.
> 
> Jim
> 

I don't want to make a big deal out of it, but I'm also not a fan of the 
lldb-forward header. My two main reasons are:
- it's inconsistent with the rest of llvm, which does not have any 
headers of such sort (LLVM.h, which we talked about last time, is the 
only thing remotely similar, but that's still has a much more narrow scope)
- it makes it easier to violate layering. Eg. right now I can type 
something like:
void do_stuff_with(Target *);
in to a "Utility" header, and it will compile just fine because it will 
have the forward-declaration of the Target class available even though 
nothing in Utility should know about that class.

Neither of these is a big problem: this is not the most important thing 
we differ from llvm, and also the layering violation will become obvious 
once you start to implement the "do_stuff_with" function (because you 
will hopefully need to include the right header to get the full 
definition). However, for these reasons, I would prefer if we got rid of 
this header, or at least moved towards a world where we have one 
forward-declaring header for each top-level module (so 
"lldb/Utility/forward.h", would forward-declare only Utility stuff, etc.).

pl