2013-11-21 Edward Smith-Rowland <3dw4rd@verizon.net>

	* include/experimental/string_view: Rep empty string with unit-length
	static constexpr string. Uncomment _GLIBCXX_VISIBILITY. Enforce
	invariant of no nullptr string pointer.
	* include/experimental/string_view.tcc: Ditto.
	* testsuite/experimental/string_view/cons/char/1.cc: data() for empty
	string_view is no longer nullptr.
	* testsuite/experimental/string_view/cons/wchar_t/1.cc: Ditto.
	* testsuite/experimental/string_view/operations/data/char/1.cc: Ditto.
	* testsuite/experimental/string_view/operations/data/wchar_t/1.cc:
	Ditto.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@205213 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 16 insertions, 14 deletions

diff --git a/libstdc++-v3/testsuite/experimental/string_view/cons/char/1.cc b/libstdc++-v3/testsuite/experimental/string_view/cons/char/1.cc
index 4bb22098df1..982a4c76fb5 100644
--- a/libstdc++-v3/testsuite/experimental/string_view/cons/char/1.cc
+++ b/libstdc++-v3/testsuite/experimental/string_view/cons/char/1.cc
@@ -33,7 +33,7 @@ test01()
   // basic_string_view()
   const std::experimental::string_view str00{};
   VERIFY( str00.length() == 0 );
-  VERIFY( str00.data() == nullptr );
+  VERIFY( str00.data() != nullptr );
 
   // basic_string_view(const char*)
   const char str_lit01[] = "rodeo beach, marin";
@@ -53,10 +53,11 @@ test01()
   std::experimental::string_view str05{str_lit01, len_lit01};
   VERIFY( str05.length() == len_lit01 );
   VERIFY( str05.data() == str_lit01 );
-  //  This is invalid and unchecked.
-  //std::experimental::string_view str06{nullptr, len_lit01};
-  //VERIFY( str06.length() == 0 );
-  //VERIFY( str06.data() == nullptr );
+
+  //  basic_string_view(const char* s, std::size_t l)
+  std::experimental::string_view str06{nullptr, len_lit01};
+  VERIFY( str06.length() == 0 );
+  VERIFY( str06.data() != nullptr );
 
   // basic_string_view(basic_string& s)
   std::string istr07(10, 'z');
diff --git a/libstdc++-v3/testsuite/experimental/string_view/cons/wchar_t/1.cc b/libstdc++-v3/testsuite/experimental/string_view/cons/wchar_t/1.cc
index 3028f654bf0..eb115fd5528 100644
--- a/libstdc++-v3/testsuite/experimental/string_view/cons/wchar_t/1.cc
+++ b/libstdc++-v3/testsuite/experimental/string_view/cons/wchar_t/1.cc
@@ -33,7 +33,7 @@ test01()
   // basic_string_view()
   const std::experimental::wstring_view str00{};
   VERIFY( str00.length() == 0 );
-  VERIFY( str00.data() == nullptr );
+  VERIFY( str00.data() != nullptr );
 
   // basic_string_view(const char*)
   const wchar_t str_lit01[] = L"rodeo beach, marin";
@@ -53,10 +53,11 @@ test01()
   std::experimental::wstring_view str05{str_lit01, len_lit01};
   VERIFY( str05.length() == len_lit01 );
   VERIFY( str05.data() == str_lit01 );
-  //  This is invalid and unchecked.
-  //std::experimental::wstring_view str06{nullptr, len_lit01};
-  //VERIFY( str06.length() == 0 );
-  //VERIFY( str06.data() == nullptr );
+
+  //  basic_string_view(const wchar_t* s, std::size_t l)
+  std::experimental::wstring_view str06{nullptr, len_lit01};
+  VERIFY( str06.length() == 0 );
+  VERIFY( str06.data() != nullptr );
 
   // basic_string_view(basic_string& s)
   std::wstring istr07(10, L'z');
diff --git a/libstdc++-v3/testsuite/experimental/string_view/operations/data/char/1.cc b/libstdc++-v3/testsuite/experimental/string_view/operations/data/char/1.cc
index 4f2bd3dba5c..be75de91791 100644
--- a/libstdc++-v3/testsuite/experimental/string_view/operations/data/char/1.cc
+++ b/libstdc++-v3/testsuite/experimental/string_view/operations/data/char/1.cc
@@ -29,10 +29,10 @@ test01()
 
   std::experimental::string_view empty;
 
-  // data() for size == 0 is non-NULL?
+  // data() for size == 0 is non-NULL.
   VERIFY( empty.size() == 0 );
   const std::experimental::string_view::value_type* p = empty.data();
-  VERIFY( p == nullptr );
+  VERIFY( p );
 
   return 0;
 }
diff --git a/libstdc++-v3/testsuite/experimental/string_view/operations/data/wchar_t/1.cc b/libstdc++-v3/testsuite/experimental/string_view/operations/data/wchar_t/1.cc
index d577c9f3c0a..5e00b00b601 100644
--- a/libstdc++-v3/testsuite/experimental/string_view/operations/data/wchar_t/1.cc
+++ b/libstdc++-v3/testsuite/experimental/string_view/operations/data/wchar_t/1.cc
@@ -29,10 +29,10 @@ test01()
 
   std::experimental::wstring_view empty;
 
-  // data() for size == 0 is non-NULL?
+  // data() for size == 0 is non-NULL.
   VERIFY( empty.size() == 0 );
   const std::experimental::wstring_view::value_type* p = empty.data();
-  VERIFY( p == nullptr );
+  VERIFY( p );
 
   return 0;
 }