From 096e268764397f781e72619e3b5f546d5786cae1 Mon Sep 17 00:00:00 2001 From: Lars Knoll Date: Wed, 5 Aug 2020 10:21:21 +0200 Subject: Avoid UB in moc generated code Introduce a Q_OFFSETOF() macro that uses the optional support of offsetof() for non standard layout types and disables the corresponding compiler warnings. All our supported compilers support offsetof() on non standard layout types. Use the macro to do the offset calculations required in moc generated code to replace a manual offset calculation that was dereferencing a null pointer. Change-Id: I4aab3af3c8bbaa90372f2234aa1cf8399d023c22 Reviewed-by: Thiago Macieira --- src/tools/moc/generator.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/tools/moc') diff --git a/src/tools/moc/generator.cpp b/src/tools/moc/generator.cpp index da3f22aa96..06b2ffc06f 100644 --- a/src/tools/moc/generator.cpp +++ b/src/tools/moc/generator.cpp @@ -1613,7 +1613,7 @@ void Generator::generateQPropertyApi() for (const PrivateQPropertyDef &property: cdef->privateQProperties) { auto printAccessor = [this, property](bool constAccessor = false) { const char *constOrNot = constAccessor ? "const " : " "; - fprintf(out, " const size_t propertyMemberOffset = reinterpret_cast(&(static_cast<%s *>(nullptr)->%s));\n", cdef->qualified.constData(), property.name.constData()); + fprintf(out, " const size_t propertyMemberOffset = Q_OFFSETOF(%s, %s);\n", cdef->qualified.constData(), property.name.constData()); fprintf(out, " %sauto *thisPtr = reinterpret_cast<%s%s *>(reinterpret_cast<%schar *>(this) - propertyMemberOffset);\n", constOrNot, constOrNot, cdef->qualified.constData(), constOrNot); }; -- cgit v1.2.3