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

[Nathan Chancellor]

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.

Cheers,
Nathan