Re: [PATCH] [PATCH] [gdb] adds `<iterator>` to list of includes

[Enze Li <enze.li@hotmail.com>]

Hi Christopher,

Unfortunately, since I don't have a ChromeBook, I can not reproduce the
problem you encountered.

I tried to reproduce your problem on a x86_64-linux device and still
did not reproduce it with the trunk.  After digging into this deeply, I
found that 'gdb/value.c' has already includes the 'vector' header file
after preprocessing.

Here's what I got,

value.c
  |--defs.h
      |--common-defs.h
          |--common-utils.h (#include <vector>)

Finally, I noticed that you were compiling gdb-9.2.  I know nothing
about the maintenance of closed branch.  You may want to keep PING and
maintainers would show up to look at this.

Thanks,
Enze

On Fri, 2022-07-01 at 14:50 -0700, Christopher Di Bella wrote:
> Hi Enze,
> 
> `std::back_inserter` is defined in <iterator>, which isn't included
> in `gdb/value.c`. Because the C preprocessor imports headers by
> copy/pasting the contents at the `#include` site, this means that
> another standard library header is exposing it (presumably
> `<algorithm>`).
> 
> We experienced this on ChromeOS, which uses Clang and libc++ to build
> things.
> 
> ```
> /tmp/portage/sys-devel/gdb-9.2.20200923-r7/work/gdb-
> 9.2/gdb/value.c:1648:52: error: no member named 'back_inserter' in
> namespace 'std'
>        std::move (iter + 1, all_values.end (), std::back_inserter
> (result));
>                                                ~~~~~^
>  1 error generated.
> ```
> 
> On Fri, 1 Jul 2022 at 06:45, Enze Li <enze.li@hotmail.com> wrote:
> > On Tue, 2022-06-28 at 01:04 +0000, Christopher Di Bella via Gdb-
> > patches
> > wrote:
> > > `std::back_inserter` is defined in `<iterator>`, which is
> > > currently
> > > being transitively included by one of the other headers. This is
> > > causing
> > > gdb to fail to build on certain platforms, which is fixed by
> > > explicitly
> > > including it.
> > 
> > Hi Christopher,
> > 
> > I didn't get your point through the commit message.  Can you
> > clarify
> > exactly on which platforms, and what build error you encountered? 
> > So
> > that I can reproduce the issue.
> > 
> > Thanks,
> > Enze
> > 
> > 
> > > ---
> > >  gdb/value.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/gdb/value.c b/gdb/value.c
> > > index 022fca91a42..ba7ae1a0e18 100644
> > > --- a/gdb/value.c
> > > +++ b/gdb/value.c
> > > @@ -40,6 +40,7 @@
> > >  #include "cp-abi.h"
> > >  #include "user-regs.h"
> > >  #include <algorithm>
> > > +#include <iterator>
> > >  #include "completer.h"
> > >  #include "gdbsupport/selftest.h"
> > >  #include "gdbsupport/array-view.h"
> > 
> 
>