linux-kernel - Re: [PATCH 3/8] riscv: init: merge split string literals in preprocessor directive

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Message-ID: <20191018054701.sjueyb3agoaopnla@ltop.local>
Date:   Fri, 18 Oct 2019 07:47:02 +0200
From:   Luc Van Oostenryck <luc.vanoostenryck@...il.com>
To:     Paul Walmsley <paul.walmsley@...ive.com>
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/8] riscv: init: merge split string literals in
 preprocessor directive

On Thu, Oct 17, 2019 at 09:38:18PM -0700, Paul Walmsley wrote:
> On Fri, 18 Oct 2019, Luc Van Oostenryck wrote:
> 
> > On Thu, Oct 17, 2019 at 05:49:24PM -0700, Paul Walmsley wrote:
> > > sparse complains loudly when string literals associated with
> > > preprocessor directives are split into multiple, separately quoted
> > > strings across different lines:
> > 
> > ...
> >  
> > >  #ifndef __riscv_cmodel_medany
> > > -#error "setup_vm() is called from head.S before relocate so it should "
> > > -	"not use absolute addressing."
> > > +#error "setup_vm() is called from head.S before relocate so it should not use absolute addressing."
> > >  #endif

...
 
> On the other hand, gcc seems to support the non-backslashed syntax.  So if 
> the intention is for sparse to follow the gcc practice, and to be used 
> beyond the kernel, maybe it's worth aligning sparse to gcc?  Only if 
> you're bored, I suppose...

I quickly checked and gcc also complain about the second line:
	$ cat y.c 
#ifndef __riscv_cmodel_medany
#error "setup_vm() is called from head.S before relocate so it should "
       "not use absolute addressing."
#endif

	$ gcc -c y.c
y.c:2:2: error: #error "setup_vm() is called from head.S before relocate so it should "
 #error "setup_vm() is called from head.S before relocate so it should "
  ^~~~~
y.c:3:8: error: expected identifier or '(' before string constant
        "not use absolute addressing."
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

So it seems that gcc doesn't join these lines.
Fell free to add my:
Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck@...il.com>

-- Luc