* [PATCH,AIX] ctype_inline.h cast and thread-safe access to __lc_type
@ 2021-01-20 23:04 David Edelsohn
0 siblings, 0 replies; only message in thread
From: David Edelsohn @ 2021-01-20 23:04 UTC (permalink / raw)
To: GCC Patches, libstdc++
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.
* 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 --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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