Re: [PATCH 4.9 061/102] scripts/dtc: Remove redundant YYLOC global declaration

[Greg Kroah-Hartman]

On Wed, Apr 01, 2020 at 02:25:53PM -0700, Nathan Chancellor wrote:
> On Wed, Apr 01, 2020 at 06:18:04PM +0200, Greg Kroah-Hartman wrote:
> > From: Dirk Mueller <dmueller@xxxxxxxx>
> > 
> > commit e33a814e772cdc36436c8c188d8c42d019fda639 upstream.
> > 
> > gcc 10 will default to -fno-common, which causes this error at link
> > time:
> > 
> >   (.text+0x0): multiple definition of `yylloc'; dtc-lexer.lex.o (symbol from plugin):(.text+0x0): first defined here
> > 
> > This is because both dtc-lexer as well as dtc-parser define the same
> > global symbol yyloc. Before with -fcommon those were merged into one
> > defintion. The proper solution would be to to mark this as "extern",
> > however that leads to:
> > 
> >   dtc-lexer.l:26:16: error: redundant redeclaration of 'yylloc' [-Werror=redundant-decls]
> >    26 | extern YYLTYPE yylloc;
> >       |                ^~~~~~
> > In file included from dtc-lexer.l:24:
> > dtc-parser.tab.h:127:16: note: previous declaration of 'yylloc' was here
> >   127 | extern YYLTYPE yylloc;
> >       |                ^~~~~~
> > cc1: all warnings being treated as errors
> > 
> > which means the declaration is completely redundant and can just be
> > dropped.
> > 
> > Signed-off-by: Dirk Mueller <dmueller@xxxxxxxx>
> > Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> > [robh: cherry-pick from upstream]
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > 
> > ---
> >  scripts/dtc/dtc-lexer.l |    1 -
> >  1 file changed, 1 deletion(-)
> > 
> > --- a/scripts/dtc/dtc-lexer.l
> > +++ b/scripts/dtc/dtc-lexer.l
> > @@ -38,7 +38,6 @@ LINECOMMENT	"//".*\n
> >  #include "srcpos.h"
> >  #include "dtc-parser.tab.h"
> >  
> > -YYLTYPE yylloc;
> >  extern bool treesource_error;
> >  
> >  /* CAUTION: this will stop working if we ever use yyless() or yyunput() */
> > 
> > 
> 
> Hi Greg,
> 
> Please see my email on the 5.5 version of this patch:
> 
> https://lore.kernel.org/stable/20200331192515.GA39354@ubuntu-m2-xlarge-x86/
> 
> As it stands how, this version of the patch does nothing.

I have picked those up now, sorry for the delay.

greg k-h