[libcxx] Fix all occurrences of -Wsign-compare in the headers

[EricWF]

Summary

The title says it all. Thanks to STL for cleaning up all occurrences in the tests so we can find these.

[EricWF]

Another fix was applied for this.

include/__bit_reference

 // find
 
 template <class _Cp, bool _IsConst>
 __bit_iterator<_Cp, _IsConst>
 __find_bool_true(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
 {
     typedef __bit_iterator<_Cp, _IsConst> _It;
     typedef typename _It::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _It::__bits_per_word;
+    static const int __bits_per_word = _It::__bits_per_word;
     // do first partial word
     if (__first.__ctz_ != 0)
     {
         __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
         __storage_type __dn = _VSTD::min(__clz_f, __n);
         __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
         __storage_type __b = *__first.__seg_ & __m;
         if (__b)

 }
 
 template <class _Cp, bool _IsConst>
 __bit_iterator<_Cp, _IsConst>
 __find_bool_false(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
 {
     typedef __bit_iterator<_Cp, _IsConst> _It;
     typedef typename _It::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _It::__bits_per_word;
+    static const int __bits_per_word = _It::__bits_per_word;
     // do first partial word
     if (__first.__ctz_ != 0)
     {
         __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
         __storage_type __dn = _VSTD::min(__clz_f, __n);
         __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
         __storage_type __b = ~*__first.__seg_ & __m;
         if (__b)

 
 template <class _Cp, bool _IsConst>
 typename __bit_iterator<_Cp, _IsConst>::difference_type
 __count_bool_true(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
 {
     typedef __bit_iterator<_Cp, _IsConst> _It;
     typedef typename _It::__storage_type __storage_type;
     typedef typename _It::difference_type difference_type;
-    static const unsigned __bits_per_word = _It::__bits_per_word;
+    static const int __bits_per_word = _It::__bits_per_word;
     difference_type __r = 0;
     // do first partial word
     if (__first.__ctz_ != 0)
     {
         __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
         __storage_type __dn = _VSTD::min(__clz_f, __n);
         __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
         __r = _VSTD::__pop_count(*__first.__seg_ & __m);

 
 template <class _Cp, bool _IsConst>
 typename __bit_iterator<_Cp, _IsConst>::difference_type
 __count_bool_false(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
 {
     typedef __bit_iterator<_Cp, _IsConst> _It;
     typedef typename _It::__storage_type __storage_type;
     typedef typename _It::difference_type difference_type;
-    static const unsigned __bits_per_word = _It::__bits_per_word;
+    static const int __bits_per_word = _It::__bits_per_word;
     difference_type __r = 0;
     // do first partial word
     if (__first.__ctz_ != 0)
     {
         __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
         __storage_type __dn = _VSTD::min(__clz_f, __n);
         __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
         __r = _VSTD::__pop_count(~*__first.__seg_ & __m);

 // fill_n
 
 template <class _Cp>
 void
 __fill_n_false(__bit_iterator<_Cp, false> __first, typename _Cp::size_type __n)
 {
     typedef __bit_iterator<_Cp, false> _It;
     typedef typename _It::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _It::__bits_per_word;
+    static const int __bits_per_word = _It::__bits_per_word;
     // do first partial word
     if (__first.__ctz_ != 0)
     {
         __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
         __storage_type __dn = _VSTD::min(__clz_f, __n);
         __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
         *__first.__seg_ &= ~__m;
         __n -= __dn;

 }
 
 template <class _Cp>
 void
 __fill_n_true(__bit_iterator<_Cp, false> __first, typename _Cp::size_type __n)
 {
     typedef __bit_iterator<_Cp, false> _It;
     typedef typename _It::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _It::__bits_per_word;
+    static const int __bits_per_word = _It::__bits_per_word;
     // do first partial word
     if (__first.__ctz_ != 0)
     {
         __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
         __storage_type __dn = _VSTD::min(__clz_f, __n);
         __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
         *__first.__seg_ |= __m;
         __n -= __dn;

 template <class _Cp, bool _IsConst>
 __bit_iterator<_Cp, false>
 __copy_aligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
                                                      __bit_iterator<_Cp, false> __result)
 {
     typedef __bit_iterator<_Cp, _IsConst> _In;
     typedef  typename _In::difference_type difference_type;
     typedef typename _In::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _In::__bits_per_word;
+    static const int __bits_per_word = _In::__bits_per_word;
     difference_type __n = __last - __first;
     if (__n > 0)
     {
         // do first word
         if (__first.__ctz_ != 0)
         {
             unsigned __clz = __bits_per_word - __first.__ctz_;
             difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz), __n);

 template <class _Cp, bool _IsConst>
 __bit_iterator<_Cp, false>
 __copy_unaligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
                                                        __bit_iterator<_Cp, false> __result)
 {
     typedef __bit_iterator<_Cp, _IsConst> _In;
     typedef  typename _In::difference_type difference_type;
     typedef typename _In::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _In::__bits_per_word;
+    static const int __bits_per_word = _In::__bits_per_word;
     difference_type __n = __last - __first;
     if (__n > 0)
     {
         // do first word
         if (__first.__ctz_ != 0)
         {
             unsigned __clz_f = __bits_per_word - __first.__ctz_;
             difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz_f), __n);

 template <class _Cp, bool _IsConst>
 __bit_iterator<_Cp, false>
 __copy_backward_aligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
                                                      __bit_iterator<_Cp, false> __result)
 {
     typedef __bit_iterator<_Cp, _IsConst> _In;
     typedef  typename _In::difference_type difference_type;
     typedef typename _In::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _In::__bits_per_word;
+    static const int __bits_per_word = _In::__bits_per_word;
     difference_type __n = __last - __first;
     if (__n > 0)
     {
         // do first word
         if (__last.__ctz_ != 0)
         {
             difference_type __dn = _VSTD::min(static_cast<difference_type>(__last.__ctz_), __n);
             __n -= __dn;

 template <class _Cp, bool _IsConst>
 __bit_iterator<_Cp, false>
 __copy_backward_unaligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
                                                        __bit_iterator<_Cp, false> __result)
 {
     typedef __bit_iterator<_Cp, _IsConst> _In;
     typedef  typename _In::difference_type difference_type;
     typedef typename _In::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _In::__bits_per_word;
+    static const int __bits_per_word = _In::__bits_per_word;
     difference_type __n = __last - __first;
     if (__n > 0)
     {
         // do first word
         if (__last.__ctz_ != 0)
         {
             difference_type __dn = _VSTD::min(static_cast<difference_type>(__last.__ctz_), __n);
             __n -= __dn;

 template <class __C1, class __C2>
 __bit_iterator<__C2, false>
 __swap_ranges_aligned(__bit_iterator<__C1, false> __first, __bit_iterator<__C1, false> __last,
                       __bit_iterator<__C2, false> __result)
 {
     typedef __bit_iterator<__C1, false> _I1;
     typedef  typename _I1::difference_type difference_type;
     typedef typename _I1::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _I1::__bits_per_word;
+    static const int __bits_per_word = _I1::__bits_per_word;
     difference_type __n = __last - __first;
     if (__n > 0)
     {
         // do first word
         if (__first.__ctz_ != 0)
         {
             unsigned __clz = __bits_per_word - __first.__ctz_;
             difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz), __n);

 template <class __C1, class __C2>
 __bit_iterator<__C2, false>
 __swap_ranges_unaligned(__bit_iterator<__C1, false> __first, __bit_iterator<__C1, false> __last,
                         __bit_iterator<__C2, false> __result)
 {
     typedef __bit_iterator<__C1, false> _I1;
     typedef  typename _I1::difference_type difference_type;
     typedef typename _I1::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _I1::__bits_per_word;
+    static const int __bits_per_word = _I1::__bits_per_word;
     difference_type __n = __last - __first;
     if (__n > 0)
     {
         // do first word
         if (__first.__ctz_ != 0)
         {
             unsigned __clz_f = __bits_per_word - __first.__ctz_;
             difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz_f), __n);

 
 template <class _Cp>
 struct __bit_array
 {
     typedef typename _Cp::difference_type difference_type;
     typedef typename _Cp::__storage_type  __storage_type;
     typedef typename _Cp::__storage_pointer __storage_pointer;
     typedef typename _Cp::iterator        iterator;
-    static const unsigned __bits_per_word = _Cp::__bits_per_word;
+    static const int __bits_per_word = _Cp::__bits_per_word;
     static const unsigned _Np = 4;
 
     difference_type __size_;
     __storage_type __word_[_Np];
 
     _LIBCPP_INLINE_VISIBILITY static difference_type capacity()
         {return static_cast<difference_type>(_Np * __bits_per_word);}
     _LIBCPP_INLINE_VISIBILITY explicit __bit_array(difference_type __s) : __size_(__s) {}

 template <class _Cp, bool _IC1, bool _IC2>
 bool
 __equal_unaligned(__bit_iterator<_Cp, _IC1> __first1, __bit_iterator<_Cp, _IC1> __last1,
                   __bit_iterator<_Cp, _IC2> __first2)
 {
     typedef __bit_iterator<_Cp, _IC1> _It;
     typedef  typename _It::difference_type difference_type;
     typedef typename _It::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _It::__bits_per_word;
+    static const int __bits_per_word = _It::__bits_per_word;
     difference_type __n = __last1 - __first1;
     if (__n > 0)
     {
         // do first word
         if (__first1.__ctz_ != 0)
         {
             unsigned __clz_f = __bits_per_word - __first1.__ctz_;
             difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz_f), __n);

 template <class _Cp, bool _IC1, bool _IC2>
 bool
 __equal_aligned(__bit_iterator<_Cp, _IC1> __first1, __bit_iterator<_Cp, _IC1> __last1,
                 __bit_iterator<_Cp, _IC2> __first2)
 {
     typedef __bit_iterator<_Cp, _IC1> _It;
     typedef  typename _It::difference_type difference_type;
     typedef typename _It::__storage_type __storage_type;
-    static const unsigned __bits_per_word = _It::__bits_per_word;
+    static const int __bits_per_word = _It::__bits_per_word;
     difference_type __n = __last1 - __first1;
     if (__n > 0)
     {
         // do first word
         if (__first1.__ctz_ != 0)
         {
             unsigned __clz = __bits_per_word - __first1.__ctz_;
             difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz), __n);
public:
     typedef __bit_iterator                                                                        pointer;
     typedef typename conditional<_IsConst, __bit_const_reference<_Cp>, __bit_reference<_Cp> >::type reference;
     typedef random_access_iterator_tag                                                            iterator_category;
 
 private:
     typedef typename _Cp::__storage_type                                           __storage_type;
     typedef typename conditional<_IsConst, typename _Cp::__const_storage_pointer,
                                            typename _Cp::__storage_pointer>::type  __storage_pointer;
-    static const unsigned __bits_per_word = _Cp::__bits_per_word;
+    static const int __bits_per_word = _Cp::__bits_per_word;
 
     __storage_pointer __seg_;
     unsigned          __ctz_;
 
 public:
     _LIBCPP_INLINE_VISIBILITY __bit_iterator() _NOEXCEPT
 #if _LIBCPP_STD_VER > 11
     : __seg_(nullptr), __ctz_(0)

include/deque

 template <class _Tp, class _Allocator>
 typename deque<_Tp, _Allocator>::iterator
 deque<_Tp, _Allocator>::erase(const_iterator __f)
 {
     iterator __b = __base::begin();
     difference_type __pos = __f - __b;
     iterator __p = __b + __pos;
     allocator_type& __a = __base::__alloc();
-    if (__pos <= (__base::size() - 1) / 2)
+    if (static_cast<size_type>(__pos) <= (__base::size() - 1) / 2)
     {   // erase from front
         _VSTD::move_backward(__b, __p, _VSTD::next(__p));
         __alloc_traits::destroy(__a, _VSTD::addressof(*__b));
         --__base::size();
         ++__base::__start_;
         if (__front_spare() >= 2 * __base::__block_size)
         {
             __alloc_traits::deallocate(__a, __base::__map_.front(), __base::__block_size);

include/istream

         if (__sen)
         {
             basic_string<_CharT, _Traits> __str;
             const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__is.getloc());
             streamsize __c = 0;
             ios_base::iostate __err = ios_base::goodbit;
             _CharT __zero = __ct.widen('0');
             _CharT __one = __ct.widen('1');
-            while (__c < _Size)
+            while (static_cast<size_t>(__c) < _Size)
             {
                 typename _Traits::int_type __i = __is.rdbuf()->sgetc();
                 if (_Traits::eq_int_type(__i, _Traits::eof()))
                 {
                    __err |= ios_base::eofbit;
                    break;
                 }
                 _CharT __ch = _Traits::to_char_type(__i);

include/random

 
 template<class _Engine, size_t __p, size_t __r>
     _LIBCPP_CONSTEXPR const size_t discard_block_engine<_Engine, __p, __r>::used_block;
 
 template<class _Engine, size_t __p, size_t __r>
 typename discard_block_engine<_Engine, __p, __r>::result_type
 discard_block_engine<_Engine, __p, __r>::operator()()
 {
-    if (__n_ >= __r)
+    if (__n_ >= 0 && static_cast<size_t>(__n_) >= __r)
     {
         __e_.discard(__p - __r);
         __n_ = 0;
     }
     ++__n_;
     return __e_();
 }
 

include/regex

 
 template <class _BidirectionalIterator, class _CharT, class _Traits>
 regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>&
 regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>::operator++()
 {
     _Position __prev = __position_;
     if (__result_ == &__suffix_)
         __result_ = nullptr;
-    else if (_N_ + 1 < __subs_.size())
+    // _N_ should always be positive
+    else if (static_cast<size_t>(_N_) + 1 < __subs_.size())
     {
         ++_N_;
         __establish_result();
     }
     else
     {
         _N_ = 0;
         ++__position_;

include/vector

 typename enable_if
 <
     __is_forward_iterator<_ForwardIterator>::value,
    void
 >::type
 vector<bool, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
 {
     clear();
-    difference_type __n = _VSTD::distance(__first, __last);
+    const difference_type __ns = _VSTD::distance(__first, __last);
+    _LIBCPP_ASSERT(__ns >= 0, "invalid range specified");
+    const size_type __n = static_cast<size_type>(__ns);
     if (__n)
     {
         if (__n > capacity())
         {
             deallocate();
             allocate(__n);
         }
         __construct_at_end(__first, __last);

test/libcxx/test/config.py

def configure_warnings(self):
             self.cxx.addWarningFlagIfSupported('-Wno-attributes')
             self.cxx.addWarningFlagIfSupported('-Wno-pessimizing-move')
             self.cxx.addWarningFlagIfSupported('-Wno-c++11-extensions')
             self.cxx.addWarningFlagIfSupported('-Wno-user-defined-literals')
             # These warnings should be enabled in order to support the MSVC
             # team using the test suite; They enable the warnings below and
             # expect the test suite to be clean.
             # FIXME: Re-enable this after fixing remaining occurrences.
-            self.cxx.addWarningFlagIfSupported('-Wno-sign-compare')
+            self.cxx.addWarningFlagIfSupported('-Wsign-compare')
             # FIXME: Enable the two warnings below.
             self.cxx.addWarningFlagIfSupported('-Wno-unused-variable')
             self.cxx.addWarningFlagIfSupported('-Wno-unused-parameter')
             # TODO(EricWF) Remove the unused warnings once the test suite
             # compiles clean with them.
             self.cxx.addWarningFlagIfSupported('-Wno-unused-local-typedef')
             std = self.get_lit_conf('std', None)
             if std in ['c++98', 'c++03']: