Added alignof intrinsic support: new tests and docs.

Also added test case from issue #1946.

[SVN r46128]

test/alignment_of_test.cpp

@@ -16,6 +16,37 @@
 // VC++ emits an awful lot of warnings unless we define these:
 #ifdef BOOST_MSVC
 #  pragma warning(disable:4244)
+//
+// What follows here is the test case for issue 1946.
+//
+#include <boost/function.hpp>
+// This kind of packing is set within MSVC 9.0 headers.
+// E.g. std::ostream has it.
+#pragma pack(push,8)
+
+// The issue is gone if Root has no data members
+struct Root { int a; };
+// The issue is gone if Root is inherited non-virtually
+struct A : virtual public Root {};
+
+#pragma pack(pop)
+//
+// This class has 8-byte alignment but is 44 bytes in size, which means 
+// that elements in an array of this type will not actually be 8 byte
+// aligned.  This appears to be an MSVC bug, and throws off our 
+// alignment calculations: causing us to report a non-sensical 12-byte
+// alignment for this type.  This is fixed by using the native __alignof
+// operator.
+//
+class issue1946 :
+    public A
+{
+public:
+    // The issue is gone if the type is not a boost::function. The signature doesn't matter.
+    typedef boost::function0< void > function_type;
+    function_type m_function;
+};
+
 #endif
 
 
@@ -63,6 +94,10 @@ BOOST_CHECK_INTEGRAL_CONSTANT(::tt::alignment_of<POD_UDT>::value, ALIGNOF(POD_UD
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::alignment_of<empty_UDT>::value, ALIGNOF(empty_UDT));
 BOOST_CHECK_INTEGRAL_CONSTANT(::tt::alignment_of<union_UDT>::value, ALIGNOF(union_UDT));
 
+#if defined(BOOST_MSVC) && (BOOST_MSVC >= 1400)
+BOOST_CHECK_INTEGRAL_CONSTANT(::tt::alignment_of<issue1946>::value, ALIGNOF(issue1946));
+#endif
+
 TT_TEST_END
 
 

test/type_with_alignment_test.cpp

@@ -35,6 +35,14 @@ void check_call(const T& v)
 
 #define TYPE_WITH_ALIGNMENT_TEST(T)\
 {\
+std::cout << "\ntesting type " << typeid(T).name() << std::endl;\
+std::cout << "Alignment of T is " << ::tt::alignment_of< T >::value << std::endl;\
+std::cout << "Aligned type is " << typeid(::tt::type_with_alignment< ::tt::alignment_of< T >::value>::type).name() << std::endl;\
+std::cout << "Alignment of aligned type is " << ::tt::alignment_of<\
+   ::tt::type_with_alignment<\
+      ::tt::alignment_of< T >::value\
+   >::type\
+>::value << std::endl;\
 BOOST_CHECK(::tt::alignment_of<\
                ::tt::type_with_alignment<\
                   ::tt::alignment_of< T >::value\
@@ -57,10 +65,6 @@ BOOST_CHECK(::tt::is_pod<\
 
 TT_TEST_BEGIN(type_with_alignment)
 
-BOOST_MESSAGE(typeid(::tt::type_with_alignment<
-                  ::tt::alignment_of<char>::value
-               >::type).name());
-
 TYPE_WITH_ALIGNMENT_TEST_EX(char)
 TYPE_WITH_ALIGNMENT_TEST_EX(short)
 TYPE_WITH_ALIGNMENT_TEST_EX(int)