Re: Statically-allocated objects with non-trivial ctors (was Re: [PATCH 33/35] Change use to type-based pool allocator in ira-color.c.)

[Jeff Law <law at redhat dot com>]

On 05/28/2015 04:42 AM, David Malcolm wrote:
> Am I right in thinking that this is a statically-allocated object with a
> non-trivial constructor?  i.e. that this constructor has to run before
> "main" is entered?
>
> Do our coding guidelines allow for this?  (I've been burned by this
> before, on a buggy C++ runtime that didn't manage to support these).
> I'm a little nervous about this, touching global state before
> "main" (e.g. from the point-of-view of the JIT), though I don't know yet
> if this is just a gut reaction, or if there's a valid concern here (I'm
> officially on holiday this week, so I haven't had a chance to dig deeply
> into these patches yet, sorry).
That idiom is used in various places by Martin's patches.   I didn't see 
a strong rhyme or reason behind why it was used over allocating 
something in automatic or heap storage.

As to supporting it, I'm not terribly concerned about other buggy C++ 
runtimes.  GCC bootstraps with GCC, which means we've got our C++ 
runtime.  The only worry becomes the low level bits that we build our 
static ctor/dtor support on top of -- and I haven't seen major problems 
with that for eons.

jeff