From 31c7b24aa5f57fbe8258c9e9845c8d630af4aec1 Mon Sep 17 00:00:00 2001 From: Marc Mutz Date: Fri, 1 Apr 2016 23:55:25 +0200 Subject: Silence MSVC warnings when using certain std algorithms The MSVC STL warns when passing naked pointers as non-bounded iterators to algorithms such as std::equal and std::copy, in an attempt to inform users that the range specified by that iterator has an implicit minimum size that the caller of the algorithm must ensure is met: warning C4996: 'std::_Equal1': Function call with parameters that may be unsafe - \ this call relies on the caller to check that the passed values are correct. To \ disable this warning, use -D_SCL_SECURE_NO_WARNINGS. See documentation on how to \ use Visual C++ 'Checked Iterators' When building Qt, as well as when building user projects with qmake (cf. 0a76b6bc7f98900ea884cd10ccca1a332e5bdba5), we globally disable this warning (with -D_SCL_SECURE_NO_WARNINGS), but since we started using STL algorithms in public headers (e.g. in qvector.h), users get this warning in their own projects now, unless they, too, define said macro. But such a requirement is against the Qt policy to have headers that are warning-free as much as possible. The suggested way of fixing this warning is to wrap the naked pointer in a stdext::unchecked_array_iterator before passing it to the algorithm, cf. examples in https://msdn.microsoft.com/en-us/library/ttcz0bys%28v=vs.120%29.aspx or, together with the capacity-made-explicit, in a stdext::checked_array_iterator. To avoid ifdefs for platforms that don't have these extensions (which, incidentally, for the unchecked case, includes MSVC 2012), wrap the calls in macros. The end game here is to drop -D_SCL_SECURE_NO_WARNINGS, at least for public headers, even though this commit also adds the wrapper to implementation and private header files. An alternative to the wrapper would have been the version of std::equal that takes four iterators. However, that is a C++14 library feature, while this version of Qt still needs to compile with a C++98 compiler, and, more importantly, there isn't, and never will be, a corresponding 4-iterator version of std::copy. Task-number: QTBUG-47948 Done-with: Stephen Kelly Change-Id: I1bbab257fb5f1c5042939c382a412b596112ff26 Reviewed-by: Stephen Kelly --- src/corelib/global/qcompilerdetection.h | 12 ++++++++++++ src/corelib/kernel/qcoreapplication.cpp | 2 +- src/corelib/tools/qlist.h | 2 +- src/corelib/tools/qvarlengtharray.h | 7 ++++--- src/corelib/tools/qvector.h | 2 +- 5 files changed, 19 insertions(+), 6 deletions(-) (limited to 'src/corelib') diff --git a/src/corelib/global/qcompilerdetection.h b/src/corelib/global/qcompilerdetection.h index b11237dce5..25043dab75 100644 --- a/src/corelib/global/qcompilerdetection.h +++ b/src/corelib/global/qcompilerdetection.h @@ -94,6 +94,12 @@ # define Q_DECL_DEPRECATED_X(text) __declspec(deprecated(text)) # define Q_DECL_EXPORT __declspec(dllexport) # define Q_DECL_IMPORT __declspec(dllimport) +# if _MSC_VER >= 1800 +# define QT_MAKE_UNCHECKED_ARRAY_ITERATOR(x) stdext::make_unchecked_array_iterator(x) +# endif +# if _MSC_VER >= 1500 +# define QT_MAKE_CHECKED_ARRAY_ITERATOR(x, N) stdext::make_checked_array_iterator(x, size_t(N)) +# endif /* Intel C++ disguising as Visual C++: the `using' keyword avoids warnings */ # if defined(__INTEL_COMPILER) # define Q_DECL_VARIABLE_DEPRECATED @@ -1117,6 +1123,12 @@ #ifndef Q_DECL_CONST_FUNCTION # define Q_DECL_CONST_FUNCTION Q_DECL_PURE_FUNCTION #endif +#ifndef QT_MAKE_UNCHECKED_ARRAY_ITERATOR +# define QT_MAKE_UNCHECKED_ARRAY_ITERATOR(x) (x) +#endif +#ifndef QT_MAKE_CHECKED_ARRAY_ITERATOR +# define QT_MAKE_CHECKED_ARRAY_ITERATOR(x, N) (x) +#endif /* * Warning/diagnostic handling diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp index 30a3204d3d..b3b35dc9b6 100644 --- a/src/corelib/kernel/qcoreapplication.cpp +++ b/src/corelib/kernel/qcoreapplication.cpp @@ -444,7 +444,7 @@ QCoreApplicationPrivate::QCoreApplicationPrivate(int &aargc, char **aargv, uint if (!isArgvModified(argc, argv)) { origArgc = argc; origArgv = new char *[argc]; - std::copy(argv, argv + argc, origArgv); + std::copy(argv, argv + argc, QT_MAKE_CHECKED_ARRAY_ITERATOR(origArgv, argc)); } #endif // Q_OS_WIN && !Q_OS_WINRT diff --git a/src/corelib/tools/qlist.h b/src/corelib/tools/qlist.h index 9a57a2c6a5..e04a6be1ab 100644 --- a/src/corelib/tools/qlist.h +++ b/src/corelib/tools/qlist.h @@ -846,7 +846,7 @@ inline bool QList::op_eq_impl(const QList &l, QListData::ArrayCompatibleLayou const T *lb = reinterpret_cast(l.p.begin()); const T *b = reinterpret_cast(p.begin()); const T *e = reinterpret_cast(p.end()); - return std::equal(b, e, lb); + return std::equal(b, e, QT_MAKE_CHECKED_ARRAY_ITERATOR(lb, l.p.size())); } template diff --git a/src/corelib/tools/qvarlengtharray.h b/src/corelib/tools/qvarlengtharray.h index bb15d66439..8371352061 100644 --- a/src/corelib/tools/qvarlengtharray.h +++ b/src/corelib/tools/qvarlengtharray.h @@ -96,7 +96,8 @@ public: QVarLengthArray &operator=(std::initializer_list list) { resize(list.size()); - std::copy(list.begin(), list.end(), this->begin()); + std::copy(list.begin(), list.end(), + QT_MAKE_CHECKED_ARRAY_ITERATOR(this->begin(), this->size())); return *this; } #endif @@ -467,7 +468,7 @@ Q_OUTOFLINE_TEMPLATE typename QVarLengthArray::iterator QVarLengthA int l = int(aend - ptr); int n = l - f; if (QTypeInfo::isComplex) { - std::copy(ptr + l, ptr + s, ptr + f); + std::copy(ptr + l, ptr + s, QT_MAKE_CHECKED_ARRAY_ITERATOR(ptr + f, s - f)); T *i = ptr + s; T *b = ptr + s - n; while (i != b) { @@ -489,7 +490,7 @@ bool operator==(const QVarLengthArray &l, const QVarLengthArray diff --git a/src/corelib/tools/qvector.h b/src/corelib/tools/qvector.h index 3ce33fb477..691872cb36 100644 --- a/src/corelib/tools/qvector.h +++ b/src/corelib/tools/qvector.h @@ -767,7 +767,7 @@ bool QVector::operator==(const QVector &v) const const T *vb = v.d->begin(); const T *b = d->begin(); const T *e = d->end(); - return std::equal(b, e, vb); + return std::equal(b, e, QT_MAKE_CHECKED_ARRAY_ITERATOR(vb, v.d->size)); } template -- cgit v1.2.3