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From: David Edelsohn <dje@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r11-6826] aix: make ctype_inline.h thread-safe and avoid _OBJ_DATA char subscript. Date: Wed, 20 Jan 2021 23:04:57 +0000 (GMT) [thread overview] Message-ID: <20210120230457.C33723971822@sourceware.org> (raw) https://gcc.gnu.org/g:fb39c4fe445beab2e2bf9402a8ccb3c541f2aa5c commit r11-6826-gfb39c4fe445beab2e2bf9402a8ccb3c541f2aa5c Author: David Edelsohn <dje.gcc@gmail.com> Date: Tue Jan 19 22:24:08 2021 -0500 aix: make ctype_inline.h thread-safe and avoid _OBJ_DATA char subscript. g++.dg/warn/Wstringop-overflow-6.C tests for a bogus overflow warning in system headers. This testcase was generating a -Wchar-subscript warning on AIX because ctype_inline.h was subscripting AIX _OBJ_DATA using a char. The _M_table case cast the subscript to unsigned char, but the _OBJ_DATA case did not. The investigation also exposed that AIX has added a thread-safe variant of access to __lc_type that had not been applied to the libstdc++ implementation. This patch casts the subscript to unsigned char and adds the THREAD_SAFE variant. libstdc++ always is compiled with pthreads, but it is good to make the situation explicit and to document the appropriate usage. Bootstrapped on powerpc-ibm-aix7.2.3.0. libstdc++-v3/ChangeLog: * config/os/aix/ctype_inline.h (bool ctype<char>:: is): Cast _OBJ_DATA subscript to unsigned char. Add _THREAD_SAFE access to __lc_type. (const char* ctype<char>:: is): Same. Diff: --- libstdc++-v3/config/os/aix/ctype_inline.h | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/config/os/aix/ctype_inline.h b/libstdc++-v3/config/os/aix/ctype_inline.h index 1faa19d8678..696fcfbf85a 100644 --- a/libstdc++-v3/config/os/aix/ctype_inline.h +++ b/libstdc++-v3/config/os/aix/ctype_inline.h @@ -45,7 +45,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION if(_M_table) return _M_table[static_cast<unsigned char>(__c)] & __m; else - return __OBJ_DATA(__lc_ctype)->mask[__c] & __m; +#ifdef _THREAD_SAFE + return __OBJ_DATA((*__lc_ctype_ptr))->mask[static_cast<unsigned char>(__c)] & __m; +#else + return __OBJ_DATA(__lc_ctype)->mask[static_cast<unsigned char>(__c)] & __m; +#endif } const char* @@ -57,7 +61,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION *__vec++ = _M_table[static_cast<unsigned char>(*__low++)]; else while (__low < __high) - *__vec++ = __OBJ_DATA(__lc_ctype)->mask[*__low++]; +#ifdef _THREAD_SAFE + *__vec++ = __OBJ_DATA((*__lc_ctype_ptr))->mask[static_cast<unsigned char>(*__low++)]; +#else + *__vec++ = __OBJ_DATA(__lc_ctype)->mask[static_cast<unsigned char>(*__low++)]; +#endif return __high; }
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