Re: Bison 3.5 - y.tab.c generates compiler warnings

Akim Demaille <[email protected]>
Newsgroups gmane.comp.parsers.bison.bugs
Message-ID <[email protected]>

> Le 29 déc. 2019 à 09:09, Akim Demaille <[email protected]> a écrit :
> 
> Hi guys,
> 
>> Le 19 déc. 2019 à 07:22, Akim Demaille <[email protected]> a écrit :
>> 
>> But so far I was unable to reproduce that warning (https://travis-ci.org/akimd/bison/builds/626034753), and if we want to commit avoiding this warning, we should also add it to the set of warnings we check.
> 
> I am still unable to reproduce it on Bison's test suite.  I tried three other architectures on Travis (PPC64le, ARM64 and s390x), I also tried GCC's -funsigned-char, but I still cannot reproduce it.
> 
> I wish I had a CI that could check that case.

Well, I'm installing this anyway.  Andy, it would be great if you could run the full test suite, I guess yacc.c is not the only place where we have to take care of this.

Cheers!

commit 78bb152a63f711af65364881c434af4c198e1ee0
Author: Akim Demaille <[email protected]>
Date:   Tue Dec 17 06:39:09 2019 +0100

   tests: also check -Wchar-subscripts

   GCC's -Wchar-subscripts may report issues on platforms where char is
   unsigned.  Unfortunately the current CI does not reproduce the
   problem.  But that would allow contributors to report issues if the
   warning appears somewhere.

   See 139d0655947c87f90af08718618feaaca0e558d7.
   Problem reported by Andy Fiddaman in:
   https://lists.gnu.org/r/bug-bison/2019-12/msg00021.html

   * configure.ac (warn_common): Add -Wchar-subscripts.

diff --git a/configure.ac b/configure.ac
index 7a80eac1..240ca3d5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -100,7 +100,8 @@ if test "$enable_gcc_warnings" = yes; then
  # -Wno-tautological-constant-out-of-range-compare for Clang 3.3 and
  # 3.4 on GNU/Linux that choke on intprops.h's INT_MULTIPLY_WRAPV,
  # etc.
-  warn_common='-Wall -Wextra -Wcast-align
+  warn_common='-Wall -Wextra
+    -Wcast-align -Wchar-subscripts
    -fparse-all-comments -Wdocumentation
    -Wformat -Wimplicit-fallthrough -Wnull-dereference
    -Wno-sign-compare -Wno-tautological-constant-out-of-range-compare
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