Re: bison-3.1.91 released [beta]

[Akim Demaille]

> Le 22 oct. 2018 à 19:10, Derek Clegg <address@hidden> a écrit :
> 
> On Oct 22, 2018, at 10:42 AM, Akim Demaille <address@hidden> wrote:
>> 
>> Hi Derek!
>> 
>>> Le 21 oct. 2018 à 19:43, Derek Clegg <address@hidden> a écrit :
>>> 
>>> I’m seeing a minor warning when building bison-3.1.91:
>>> 
>>> lib/obstack.c:351:31: warning: incompatible pointer types initializing 'void
>>>    (*)(void) __attribute__((noreturn))' with an expression of type
>>>    'void (void)' [-Wincompatible-pointer-types]
>>> __attribute_noreturn__ void (*obstack_alloc_failed_handler) (void)
>>> ...
>> 
>> This is coming from gnulib.  Could you submit your patch there?
>> I don’t know how they handle _Noreturn.
>> 
>> address@hidden
> 
> Thanks for the reply; I’ll do that. I’ll note that data/c.m4 has this:
> 
> #if !defined _Noreturn \
>     && (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112)
> # if defined _MSC_VER && 1200 <= _MSC_VER
> #  define _Noreturn __declspec (noreturn)
> # else
> #  define _Noreturn YY_ATTRIBUTE ((__noreturn__))
> # endif
> #endif
> 
> That makes it into the generated header, and produces the warning
> 
> aux/x.h:97:11: error: macro name is a reserved identifier
>      [-Werror,-Wreserved-id-macro]
> #  define _Noreturn YY_ATTRIBUTE ((__noreturn__))
> 
> As this isn’t used anywhere (as far as I can tell), it seems reasonable to 
> omit it.

I’ll install this soon.  Thanks!

commit b5515215c188a48c0a9956a5cb03ddb951870477
Author: Akim Demaille <address@hidden>
Date:   Tue Oct 23 07:12:09 2018 +0200

    yacc.c: don't define _Noreturn uselessly
    
    Clang warns:
    
         aux/x.h:97:11: error: macro name is a reserved identifier
               [-Werror,-Wreserved-id-macro]
         #  define _Noreturn YY_ATTRIBUTE ((__noreturn__))
    
    Reported by Derek Clegg.
    http://lists.gnu.org/archive/html/bug-bison/2018-10/msg00024.html
    
    * data/c.m4 (b4_attribute_define): Don't define _Noreturn unconditionally.
    * data/glr.c: Ask for _Noreturn.

diff --git a/data/c.m4 b/data/c.m4
index 2ec6ceea..2df76e77 100644
--- a/data/c.m4
+++ b/data/c.m4
@@ -204,11 +204,12 @@ m4_define([b4_table_value_equals],
 ## Compiler issues.  ##
 ## ----------------- ##
 
-# b4_attribute_define
-# -------------------
-# Provide portable compiler "attributes".
+# b4_attribute_define([noreturn])
+# -------------------------------
+# Provide portable compiler "attributes".  If "noreturn" is passed, define
+# _Noreturn.
 m4_define([b4_attribute_define],
-[#ifndef YY_ATTRIBUTE
+[[#ifndef YY_ATTRIBUTE
 # if (defined __GNUC__                                               \
       && (2 < __GNUC__ || (__GNUC__ == 2 && 96 <= __GNUC_MINOR__)))  \
      || defined __SUNPRO_C && 0x5110 <= __SUNPRO_C
@@ -226,7 +227,7 @@ m4_define([b4_attribute_define],
 # define YY_ATTRIBUTE_UNUSED YY_ATTRIBUTE ((__unused__))
 #endif
 
-#if !defined _Noreturn \
+]m4_bmatch([$1], [\bnoreturn\b], [[#if !defined _Noreturn \
      && (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112)
 # if defined _MSC_VER && 1200 <= _MSC_VER
 #  define _Noreturn __declspec (noreturn)
@@ -235,7 +236,7 @@ m4_define([b4_attribute_define],
 # endif
 #endif
 
-/* Suppress unused-variable warnings by "using" E.  */
+]])[/* Suppress unused-variable warnings by "using" E.  */
 #if ! defined lint || defined __GNUC__
 # define YYUSE(E) ((void) (E))
 #else
@@ -260,7 +261,7 @@ m4_define([b4_attribute_define],
 #ifndef YY_INITIAL_VALUE
 # define YY_INITIAL_VALUE(Value) /* Nothing. */
 #endif
-])
+]])
 
 
 # b4_null_define
diff --git a/data/glr.c b/data/glr.c
index 56788b80..f77da621 100644
--- a/data/glr.c
+++ b/data/glr.c
@@ -311,7 +311,7 @@ static YYLTYPE yyloc_default][]b4_yyloc_default;])[
  } while (yyfalse)
 #endif
 
-]b4_attribute_define[
+]b4_attribute_define([noreturn])[
 
 #ifndef YYASSERT
 # define YYASSERT(Condition) ((void) ((Condition) || (abort (), 0)))