Revert accidentally-committed files.

llvm-svn: 208034

docs/CodingStandards.rst

@@ -108,8 +108,6 @@ unlikely to be supported by our host compilers.
 * Lambdas: N2927_
 
   * But *not* ``std::function``, until Clang implements `MSVC-compatible RTTI`_.
-    In many cases, you may be able to use ``llvm::function_ref`` instead, and it
-    is a superior choice in those cases.
   * And *not* lambdas with default arguments.
 
 * ``decltype``: N2343_

docs/ProgrammersManual.rst

@@ -263,78 +263,6 @@ almost never be stored or mentioned directly.  They are intended solely for use
 when defining a function which should be able to efficiently accept concatenated
 strings.
 
-.. _function_apis:
-
-Passing functions and other callable objects
---------------------------------------------
-
-Sometimes you may want a function to be passed a callback object. In order to
-support lambda expressions and other function objects, you should not use the
-traditional C approach of taking a function pointer and an opaque cookie:
-
-.. code-block:: c++
-
-    void takeCallback(bool (*Callback)(Function *, void *), void *Cookie);
-
-Instead, use one of the following approaches:
-
-Function template
-^^^^^^^^^^^^^^^^^
-
-If you don't mind putting the definition of your function into a header file,
-make it a function template that is templated on the callable type.
-
-.. code-block:: c++
-
-    template<typename Callable>
-    void takeCallback(Callable Callback) {
-      Callback(1, 2, 3);
-    }
-
-The ``function_ref`` class template
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-The ``function_ref``
-(`doxygen <http://llvm.org/doxygen/classllvm_1_1function_ref.html>`__) class
-template represents a reference to a callable object, templated over the type
-of the callable. This is a good choice for passing a callback to a function,
-if you don't need to hold onto the callback after the function returns.
-
-``function_ref<Ret(Param1, Param2, ...)>`` can be implicitly constructed from
-any callable object that can be called with arguments of type ``Param1``,
-``Param2``, ..., and returns a value that can be converted to type ``Ret``.
-For example:
-
-.. code-block:: c++
-
-    void visitBasicBlocks(Function *F, function_ref<bool (BasicBlock*)> Callback) {
-      for (BasicBlock &BB : *F)
-        if (Callback(&BB))
-          return;
-    }
-
-can be called using:
-
-.. code-block:: c++
-
-    visitBasicBlocks(F, [&](BasicBlock *BB) {
-      if (process(BB))
-        return isEmpty(BB);
-      return false;
-    });
-
-Note that a ``function_ref`` object contains pointers to external memory, so
-it is not generally safe to store an instance of the class (unless you know
-that the external storage will not be freed).
-``function_ref`` is small enough that it should always be passed by value.
-
-``std::function``
-^^^^^^^^^^^^^^^^^
-
-You cannot use ``std::function`` within LLVM code, because it is not supported
-by all our target toolchains.
-
-
 .. _DEBUG:
 
 The ``DEBUG()`` macro and ``-debug`` option