svn commit: r292120 - in head/contrib/elftoolchain: addr2line common elfcopy libelf readelf

[Dimitry Andric]

On 13 Dec 2015, at 09:43, Kai Wang <kaiw27 at gmail.com> wrote:
> 
> 2015-12-13 7:04 GMT+01:00 Adrian Chadd <adrian.chadd at gmail.com>:
> cc1: warnings being treated as errors
> /usr/home/adrian/work/freebsd/head-embedded/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:
> In function 'dump_dwarf':
> /usr/home/adrian/work/freebsd/head-embedded/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:7479:
> warning: 'b' may be used uninitialized in this function
> /usr/home/adrian/work/freebsd/head-embedded/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:7479:
> note: 'b' was declared here
> /usr/home/adrian/work/freebsd/head-embedded/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:4758:
> warning: 'pe' may be used uninitialized in this function
> /usr/home/adrian/work/freebsd/head-embedded/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:4758:
> note: 'pe' was declared here
> 
> .. these both seem like legit.
> 
> 
> Hi,
> 
> Sorry about the breakage. Should be fixed by r292158.
> Somehow clang didn't catch this. Had to use gcc to see this warning.

Indeed, this is interesting.  For clang to warn similarly, the
-Wconditional-uninitialized option has to be enabled explicitly, and
then you get a lot of them (this is from just before your commit):

/usr/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:4861:33: error: variable 'pe' may be uninitialized when used here [-Werror,-Wconditional-uninitialized]
                        dirndx = _decode_uleb128(&p, pe);
                                                     ^~
/usr/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:4758:17: note: initialize the variable 'pe' to silence this warning
        uint8_t *p, *pe;
                       ^
                        = NULL
/usr/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:6167:8: error: variable 'cie_ra' may be uninitialized when used here [-Werror,-Wconditional-uninitialized]
                            cie_ra);
                            ^~~~~~
/usr/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:6060:19: note: initialize the variable 'cie_ra' to silence this warning
        Dwarf_Half cie_ra;
                         ^
                          = 0
/usr/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:6164:8: error: variable 'cie_caf' may be uninitialized when used here [-Werror,-Wconditional-uninitialized]
                            cie_caf, cie_daf, low_pc, re->dbg);
                            ^~~~~~~
/usr/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:6057:24: note: initialize the variable 'cie_caf' to silence this warning
        Dwarf_Unsigned cie_caf, cie_daf, cie_instlen, func_len, fde_length;
                              ^
                               = 0
/usr/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:6164:17: error: variable 'cie_daf' may be uninitialized when used here [-Werror,-Wconditional-uninitialized]
                            cie_caf, cie_daf, low_pc, re->dbg);
                                     ^~~~~~~
/usr/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:6057:33: note: initialize the variable 'cie_daf' to silence this warning
        Dwarf_Unsigned cie_caf, cie_daf, cie_instlen, func_len, fde_length;
                                       ^
                                        = 0
/usr/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:7492:21: error: variable 'b' may be uninitialized when used here [-Werror,-Wconditional-uninitialized]
        if (shift < 32 && (b & 0x40) != 0)
                           ^
/usr/src/usr.bin/readelf/../../contrib/elftoolchain/readelf/readelf.c:7479:11: note: initialize the variable 'b' to silence this warning
        uint8_t b;
                 ^
                  = '\0'
5 errors generated.

I'll check if there is a specific reason upstream does not enable this
warning by default for -Wall.  Maybe there is a risk of false positives.

-Dimitry

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 194 bytes
Desc: Message signed with OpenPGP using GPGMail
URL: <http://lists.freebsd.org/pipermail/svn-src-all/attachments/20151213/94df901d/attachment.sig>