Re: [PATCH] gdb/build: Fix Wpessimizing-move in clang build

[Enze Li <lienze2010@hotmail.com>]

On Fri, 2022-01-28 at 09:58 -0500, Simon Marchi wrote:
> 
> 
> On 2022-01-28 09:33, Enze Li wrote:
> > On Fri, 2022-01-28 at 09:25 -0500, Simon Marchi wrote:
> > > 
> > > 
> > > On 2022-01-28 08:41, Enze Li via Gdb-patches wrote:
> > > > When building with clang, I run into an error:
> > > > 
> > > > ...
> > > > tui/tui-disasm.c:138:25: error: moving a temporary object
> > > > prevents
> > > > copy
> > > > elision [-Werror,-Wpessimizing-move]
> > > >       tal.addr_string = std::move (gdb_dis_out.release ());
> > > >                         ^
> > > > tui/tui-disasm.c:138:25: note: remove std::move call here
> > > >       tal.addr_string = std::move (gdb_dis_out.release ());
> > > >                         ^~~~~~~~~~~                      ~
> > > > ...
> > > > 
> > > > The error above is caused by the recent commit 5d10a2041eb8
> > > > ("gdb:
> > > > add
> > > > string_file::release method").
> > > > 
> > > > Fix this by removing std::move.
> > > > 
> > > > Build on x86_64-linux with clang 13.0.0.
> > > > ---
> > > >  gdb/tui/tui-disasm.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/gdb/tui/tui-disasm.c b/gdb/tui/tui-disasm.c
> > > > index 445503a5af9..70f7429d32b 100644
> > > > --- a/gdb/tui/tui-disasm.c
> > > > +++ b/gdb/tui/tui-disasm.c
> > > > @@ -135,7 +135,7 @@ tui_disassemble (struct gdbarch *gdbarch,
> > > >        /* And capture the address the instruction is at.  */
> > > >        tal.addr = orig_pc;
> > > >        print_address (gdbarch, orig_pc, &gdb_dis_out);
> > > > -      tal.addr_string = std::move (gdb_dis_out.release ());
> > > > +      tal.addr_string = gdb_dis_out.release ();
> > > >  
> > > >        if (addr_size != nullptr)
> > > >         {
> > > 
> > > Oh, thanks!  In fact, this is the spot that did prompt me to add
> > > this
> > > release method, so it's a silly oversight on my part to not
> > > remove
> > > the
> > > std::move.  Thanks patch is ok.  Do you have push access?
> > 
> > Yes.  Should I push it now?
> 
> Yes, please go ahead.
> 
> Simon

Okay, pushed.

Cheers!
Enze