This warning gives false positives about lldb's correct use of
strncpy to fill fixed length fields that don't need null termination,
in lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp, like this:
In file included from /usr/include/string.h:495,
from /usr/include/c++/9/cstring:42,
from ../include/llvm/ADT/StringRef.h:19,
from ../tools/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp:10:
In function ‘char* strncpy(char*, const char*, size_t)’,
inlined from ‘lldb::offset_t CreateAllImageInfosPayload(const ProcessSP&, lldb::offset_t, lldb_private::StreamString&, lldb::SaveCoreStyle)’ at ../tools/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp:6341:16:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:34: warning: ‘char* __builtin_strncpy(char*, const char*, long unsigned int)’ specified bound 16 equals destination size [-Wstringop-truncation]
106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
| ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
The warning could be squelched locally with
#pragma GCC diagnostic ignored "-Wstringop-truncation"
too, but Clang also interprets those GCC pragmas, and produces
a -Wunknown-warning-option warning instead. That could be remedied
by wrapping the pragma in an "#ifndef __clang__" - but that makes
things even more messy. Instead, just silence this warning entirely.
Differential Revision: https://reviews.llvm.org/D123254
5560b9e884