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| author | Paul Eggert <eggert@cs.ucla.edu> | 2014-11-25 14:12:48 -0800 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2014-11-25 14:20:53 -0800 |
| commit | b1eda10e17bf2056ca79a534d92fe0b0b06bd410 (patch) | |
| tree | 0ae624bdeb264f2a7a11e2fd2266f73acbc56af9 | |
| parent | bde2667a22c355467a4f07246c6d07a9dcc89366 (diff) | |
| download | glibc-b1eda10e17bf2056ca79a534d92fe0b0b06bd410.tar.gz glibc-b1eda10e17bf2056ca79a534d92fe0b0b06bd410.tar.xz glibc-b1eda10e17bf2056ca79a534d92fe0b0b06bd410.zip | |
fnmatch: work around GCC compiler warning bug with uninit var
* posix/fnmatch_loop.c (FCT): Use a scalar not a one-item array. This works around a bug with x86-64 GCC 4.9.2 and earlier where 'gcc -O2 -Wmaybe-uninitialized' incorrectly complains "../locale/weightwc.h:93:7: warning: '*((void *)&str+4)' may be used uninitialized in this function [-Wmaybe-uninitialized]".
| -rw-r--r-- | ChangeLog | 9 | ||||
| -rw-r--r-- | posix/fnmatch_loop.c | 13 |
2 files changed, 18 insertions, 4 deletions
diff --git a/ChangeLog b/ChangeLog index 8ee0650df7..c020ed42b9 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,12 @@ +2014-11-25 Paul Eggert <eggert@cs.ucla.edu> + + fnmatch: work around GCC compiler warning bug with uninit var + * posix/fnmatch_loop.c (FCT): Use a scalar not a one-item array. + This works around a bug with x86-64 GCC 4.9.2 and earlier + where 'gcc -O2 -Wmaybe-uninitialized' incorrectly complains + "../locale/weightwc.h:93:7: warning: '*((void *)&str+4)' may be + used uninitialized in this function [-Wmaybe-uninitialized]". + 2014-11-25 Joseph Myers <joseph@codesourcery.com> * posix/bug-regex31.c (main): Return RES not 0. diff --git a/posix/fnmatch_loop.c b/posix/fnmatch_loop.c index db6d9d7c56..1e27913cf1 100644 --- a/posix/fnmatch_loop.c +++ b/posix/fnmatch_loop.c @@ -343,7 +343,12 @@ FCT (pattern, string, string_end, no_leading_period, flags, ends, alloca_used) #ifdef _LIBC else if (c == L('[') && *p == L('=')) { - UCHAR str[1]; + /* It's important that STR be a scalar variable rather + than a one-element array, because GCC (at least 4.9.2 + -O2 on x86-64) can be confused by the array and + diagnose a "used initialized" in a dead branch in the + findidx function. */ + UCHAR str; uint32_t nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES); const CHAR *startp = p; @@ -355,7 +360,7 @@ FCT (pattern, string, string_end, no_leading_period, flags, ends, alloca_used) c = L('['); goto normal_bracket; } - str[0] = c; + str = c; c = *++p; if (c != L('=') || p[1] != L(']')) @@ -368,7 +373,7 @@ FCT (pattern, string, string_end, no_leading_period, flags, ends, alloca_used) if (nrules == 0) { - if ((UCHAR) *n == str[0]) + if ((UCHAR) *n == str) goto matched; } else @@ -383,7 +388,7 @@ FCT (pattern, string, string_end, no_leading_period, flags, ends, alloca_used) # endif const int32_t *indirect; int32_t idx; - const UCHAR *cp = (const UCHAR *) str; + const UCHAR *cp = (const UCHAR *) &str; # if WIDE_CHAR_VERSION table = (const int32_t *) |