Bug#853649: gnulib intprops.h build error with gcc 7
On Thu, Aug 17, 2017 at 08:40:28PM +0200, Bruno Haible wrote: >... > Now about your test case: It is not valid C to try to compile just an > expression. >... I was about to say that this was directly copied from intprops.h And when double-checking that, I finally realized that this is what is in intprops.h in rush - but intprops.h in current gnulib git is fine. When looking at them I missed that they are different at this relevant macro, and that the problem is only in the older intprops.h shipped in rush. Sorry for the confusion Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed
Bug#853649: gnulib intprops.h build error with gcc 7
Adrian Bunk wrote: > For reproducing and my tiny testcase I was using > gcc (Debian 7.1.0-13) 7.1.0 > from Debian unstable - that is GCC 7.2 release candidate 2 > with minimal Debian patching. OK thanks. Now about your test case: It is not valid C to try to compile just an expression. a + b is not a valid C compilation unit either. Can you submit a small test case that 1) makes use of the intprops.h file from gnulib as a whole, 2) compiles with gcc 6 or earlier? Bruno
Bug#853649: gnulib intprops.h build error with gcc 7
On Thu, Aug 17, 2017 at 07:02:47PM +0200, Bruno Haible wrote: > Hi Adrian, > > Could you please give the complete output of "gcc --version"? > > Given that [1] references an URL that contains the string > 'gcc7-20170126' whereas gcc 7 was released on 2017-05-02 [2], > it could be that the report is about a gcc prerelease that > came 3 months before the gcc 7 release. For reproducing and my tiny testcase I was using gcc (Debian 7.1.0-13) 7.1.0 from Debian unstable - that is GCC 7.2 release candidate 2 with minimal Debian patching. > Bruno >... cu Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed
Bug#853649: gnulib intprops.h build error with gcc 7
Hi Adrian, Could you please give the complete output of "gcc --version"? Given that [1] references an URL that contains the string 'gcc7-20170126' whereas gcc 7 was released on 2017-05-02 [2], it could be that the report is about a gcc prerelease that came 3 months before the gcc 7 release. Bruno [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=853649 [2] https://gcc.gnu.org/
Bug#853649: gnulib intprops.h build error with gcc 7
> Package: src:rush
> Version: 1.8+dfsg-1
>...
> In file included from inttostr.h:25:0,
> from anytostr.c:31,
> from imaxtostr.c:5:
> intprops.h:236:34: error: expected ')' before '(' token
> __builtin_add_overflow (a, b, (__typeof__ ((a) + (b)) *) 0)
> ^
> Makefile:1284: recipe for target 'imaxtostr.o' failed
>...
This can be reproduced with
$ cat test.c
# define _GL_ADD_OVERFLOW(a, b, min, max)
__builtin_add_overflow (a, b, (__typeof__ ((a) + (b)) *) 0)
$ gcc -c test.c
test.c:2:34: error: expected ‘)’ before ‘(’ token
__builtin_add_overflow (a, b, (__typeof__ ((a) + (b)) *) 0)
^
$
This is a problem in gnulib, introduced by
commit d22721e2efd88f26588c971eb1eeb3ec40de
Author: Paul Eggert
Date: Mon Aug 29 10:08:32 2016 -0700
intprops.h: use __typeof__ with GCC 7
* lib/intprops.h (_GL_ADD_OVERFLOW, _GL_SUBTRACT_OVERFLOW)
(_GL_MULTIPLY_OVERFLOW): Use __typeof__ as in the GCC manual.
This avoids computing the expression's value (which might overflow!).
cu
Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed
