[libcxx] Properly convert the count arguments to the *_n algorithms before use.

Summary:
The requirement on the `Size` type passed to *_n algorithms is that it is convertible to an integral type. This means we can't use a variable of type `Size` directly. Instead we need to convert it to an integral type first.  The problem is finding out what integral type to convert it to.  `__convert_to_integral` figures out what integral type to convert it to and performs the conversion, It also promotes the resulting integral type so that it is at least as big as an integer. `__convert_to_integral` also has a special case for converting enums. This should only work on non-scoped enumerations because it does not apply an explicit conversion from the enum to its underlying type.



Reviewers: chandlerc, mclow.lists

Reviewed By: mclow.lists

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D7449

llvm-svn: 228704

7 files changed, 163 insertions, 11 deletions

diff --git a/libcxx/test/libcxx/type_traits/convert_to_integral.pass.cpp b/libcxx/test/libcxx/type_traits/convert_to_integral.pass.cpp
new file mode 100644
index 00000000000..ccdc7675ad6
--- /dev/null
+++ b/libcxx/test/libcxx/type_traits/convert_to_integral.pass.cpp
@@ -0,0 +1,89 @@
+
+#include <limits>
+#include <type_traits>
+#include <cstdint>
+#include <cassert>
+
+#include "user_defined_integral.hpp"
+
+template <class T>
+struct EnumType
+{
+  enum type : T {E_zero, E_one};
+};
+
+
+template <class From, class To>
+void check_integral_types()
+{
+  typedef std::numeric_limits<From> Limits;
+  const From max = Limits::max();
+  const From min = Limits::min();
+  {
+  auto ret = std::__convert_to_integral((From)max);
+  assert(ret == max);
+  ret = std::__convert_to_integral((From)min);
+  assert(ret == min);
+  static_assert(std::is_same<decltype(ret), To>::value, "");
+  }
+  {
+  UserDefinedIntegral<From> f(max);
+  auto ret = std::__convert_to_integral(f);
+  assert(ret == max);
+  f.value = min;
+  ret = std::__convert_to_integral(f);
+  assert(ret == min);
+  static_assert(std::is_same<decltype(ret), To>::value, "");
+  }
+  {
+  typedef typename EnumType<From>::type Enum;
+  Enum e(static_cast<Enum>(max));
+  auto ret = std::__convert_to_integral(e);
+  assert(ret == max);
+  e = static_cast<Enum>(min);
+  ret = std::__convert_to_integral(min);
+  assert(ret == min);
+  static_assert(std::is_same<decltype(ret), To>::value, "");
+  }
+}
+
+
+template <class From, class To>
+void check_enum_types()
+{
+  auto ret = std::__convert_to_integral((From)1);
+  assert(ret == 1);
+  static_assert(std::is_same<decltype(ret), To>::value, "");
+}
+
+
+enum enum1 {};
+enum enum2 {
+  value = std::numeric_limits<unsigned long>::max()
+};
+
+int main()
+{
+  check_integral_types<bool, int>();
+  check_integral_types<char, int>();
+  check_integral_types<signed char, int>();
+  check_integral_types<unsigned char, int>();
+  check_integral_types<wchar_t, int>();
+  check_integral_types<char16_t, int>();
+  check_integral_types<char32_t, uint32_t>();
+  check_integral_types<short, int>();
+  check_integral_types<unsigned short, int>();
+  check_integral_types<int, int>();
+  check_integral_types<unsigned, unsigned>();
+  check_integral_types<long, long>();
+  check_integral_types<unsigned long, unsigned long>();
+  check_integral_types<long long, long long>();
+  check_integral_types<unsigned long long, unsigned long long>();
+#ifndef _LIBCPP_HAS_NO_INT128
+  check_integral_types<__int128_t, __int128_t>();
+  check_integral_types<__uint128_t, __uint128_t>();
+#endif
+    // TODO(ericwf): Not standard
+  check_enum_types<enum1, unsigned>();
+  check_enum_types<enum2, unsigned long>();
+}
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_n.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_n.pass.cpp
index f594a0bf618..1dba8847c7e 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_n.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/copy_n.pass.cpp
@@ -17,6 +17,9 @@
 #include <cassert>
 
 #include "test_iterators.h"
+#include "user_defined_integral.hpp"
+
+typedef UserDefinedIntegral<unsigned> UDI;
 
 template <class InIter, class OutIter>
 void
@@ -28,7 +31,7 @@ test()
         ia[i] = i;
     int ib[N] = {0};
 
-    OutIter r = std::copy_n(InIter(ia), N/2, OutIter(ib));
+    OutIter r = std::copy_n(InIter(ia), UDI(N/2), OutIter(ib));
     assert(base(r) == ib+N/2);
     for (unsigned i = 0; i < N/2; ++i)
         assert(ia[i] == ib[i]);
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp
index bffcf1b63cb..6617cd0916f 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp
@@ -18,6 +18,9 @@
 #include <cassert>
 
 #include "test_iterators.h"
+#include "user_defined_integral.hpp"
+
+typedef UserDefinedIntegral<unsigned> UDI;
 
 template <class Iter>
 void
@@ -25,7 +28,7 @@ test_char()
 {
     const unsigned n = 4;
     char ca[n] = {0};
-    assert(std::fill_n(Iter(ca), n, char(1)) == std::next(Iter(ca), n));
+    assert(std::fill_n(Iter(ca), UDI(n), char(1)) == std::next(Iter(ca), n));
     assert(ca[0] == 1);
     assert(ca[1] == 1);
     assert(ca[2] == 1);
@@ -38,7 +41,7 @@ test_int()
 {
     const unsigned n = 4;
     int ia[n] = {0};
-    assert(std::fill_n(Iter(ia), n, 1) == std::next(Iter(ia), n));
+    assert(std::fill_n(Iter(ia), UDI(n), 1) == std::next(Iter(ia), n));
     assert(ia[0] == 1);
     assert(ia[1] == 1);
     assert(ia[2] == 1);
@@ -50,7 +53,7 @@ test_int_array()
 {
     const unsigned n = 4;
     int ia[n] = {0};
-    assert(std::fill_n(ia, n, static_cast<char>(1)) == std::next(ia, n));
+    assert(std::fill_n(ia, UDI(n), static_cast<char>(1)) == std::next(ia, n));
     assert(ia[0] == 1);
     assert(ia[1] == 1);
     assert(ia[2] == 1);
@@ -69,7 +72,7 @@ test_int_array_struct_source()
 {
     const unsigned n = 4;
     int ia[n] = {0};
-    assert(std::fill_n(ia, n, source()) == std::next(ia, n));
+    assert(std::fill_n(ia, UDI(n), source()) == std::next(ia, n));
     assert(ia[0] == 0);
     assert(ia[1] == 1);
     assert(ia[2] == 2);
@@ -87,7 +90,7 @@ test_struct_array()
 {
     const unsigned n = 4;
     test1 test1a[n] = {0};
-    assert(std::fill_n(test1a, n, static_cast<char>(10)) == std::next(test1a, n));    
+    assert(std::fill_n(test1a, UDI(n), static_cast<char>(10)) == std::next(test1a, n));
     assert(test1a[0].c == 11);
     assert(test1a[1].c == 11);
     assert(test1a[2].c == 11);
@@ -110,7 +113,7 @@ void
 test5()
 {
     A a[3];
-    assert(std::fill_n(&a[0], 3, A('a')) == a+3);
+    assert(std::fill_n(&a[0], UDI(3), A('a')) == a+3);
     assert(a[0] == A('a'));
     assert(a[1] == A('a'));
     assert(a[2] == A('a'));
@@ -124,11 +127,11 @@ struct Storage
     unsigned char b;
   };
 };
- 
+
 void test6()
 {
   Storage foo[5];
-  std::fill_n(&foo[0], 5, Storage());
+  std::fill_n(&foo[0], UDI(5), Storage());
 }
 
 
@@ -143,7 +146,7 @@ int main()
     test_int<bidirectional_iterator<int*> >();
     test_int<random_access_iterator<int*> >();
     test_int<int*>();
-    
+
     test_int_array();
     test_int_array_struct_source();
     test_struct_array();
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate_n.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate_n.pass.cpp
index 249419169a1..a9ccaf4cd95 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate_n.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.generate/generate_n.pass.cpp
@@ -19,6 +19,9 @@
 #include <cassert>
 
 #include "test_iterators.h"
+#include "user_defined_integral.hpp"
+
+typedef UserDefinedIntegral<unsigned> UDI;
 
 struct gen_test
 {
@@ -31,7 +34,7 @@ test()
 {
     const unsigned n = 4;
     int ia[n] = {0};
-    assert(std::generate_n(Iter(ia), n, gen_test()) == Iter(ia+n));
+    assert(std::generate_n(Iter(ia), UDI(n), gen_test()) == Iter(ia+n));
     assert(ia[0] == 2);
     assert(ia[1] == 2);
     assert(ia[2] == 2);
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n.pass.cpp
index b834da210d3..f7f8ee09279 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n.pass.cpp
@@ -18,6 +18,7 @@
 #include <cassert>
 
 #include "test_iterators.h"
+#include "user_defined_integral.hpp"
 
 template <class Iter>
 void
@@ -63,6 +64,9 @@ test()
     assert(std::search_n(Iter(ic), Iter(ic+sc), 2, 0) == Iter(ic));
     assert(std::search_n(Iter(ic), Iter(ic+sc), 3, 0) == Iter(ic));
     assert(std::search_n(Iter(ic), Iter(ic+sc), 4, 0) == Iter(ic+sc));
+
+    // Check that we properly convert the size argument to an integral.
+    std::search_n(Iter(ic), Iter(ic+sc), UserDefinedIntegral<unsigned>(0), 0);
 }
 
 int main()
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n_pred.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n_pred.pass.cpp
index 6004b0e0a81..8bc6f4d26bd 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n_pred.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/search_n_pred.pass.cpp
@@ -18,6 +18,7 @@
 #include <cassert>
 
 #include "test_iterators.h"
+#include "user_defined_integral.hpp"
 
 struct count_equal
 {
@@ -29,6 +30,7 @@ struct count_equal
 
 unsigned count_equal::count = 0;
 
+
 template <class Iter>
 void
 test()
@@ -138,6 +140,10 @@ test()
     assert(std::search_n(Iter(ic), Iter(ic+sc), 4, 0, count_equal()) == Iter(ic+sc));
     assert(count_equal::count <= sc);
     count_equal::count = 0;
+
+    // Check that we properly convert the size argument to an integral.
+    std::search_n(Iter(ic), Iter(ic+sc), UserDefinedIntegral<unsigned>(4), 0, count_equal());
+    count_equal::count = 0;
 }
 
 int main()
diff --git a/libcxx/test/support/user_defined_integral.hpp b/libcxx/test/support/user_defined_integral.hpp
new file mode 100644
index 00000000000..3b0f7a19fcf
--- /dev/null
+++ b/libcxx/test/support/user_defined_integral.hpp
@@ -0,0 +1,44 @@
+#ifndef SUPPORT_USER_DEFINED_INTEGRAL_HPP
+#define SUPPORT_USER_DEFINED_INTEGRAL_HPP
+
+template <class T>
+struct UserDefinedIntegral
+{
+    UserDefinedIntegral() : value(0) {}
+    UserDefinedIntegral(T v) : value(v) {}
+    operator T() const { return value; }
+    T value;
+};
+
+// Poison the arithmetic and comparison operations
+template <class T, class U>
+void operator+(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator-(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator*(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator/(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator==(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator!=(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator<(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator>(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator<=(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+template <class T, class U>
+void operator>=(UserDefinedIntegral<T>, UserDefinedIntegral<U>);
+
+#endif // SUPPORT_USER_DEFINED_INTEGRAL_HPP