(`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.
+if you don't need to hold onto the callback after the function returns. In this
+way, ``function_ref`` is to ``std::function`` as ``StringRef`` is to
+``std::string``.
``function_ref<Ret(Param1, Param2, ...)>`` can be implicitly constructed from
any callable object that can be called with arguments of type ``Param1``,
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.
-
+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). If you need this ability, consider
+using ``std::function``. ``function_ref`` is small enough that it should always
+be passed by value.
.. _DEBUG:
because there is no system in place to ensure that names do not conflict. If
two different modules use the same string, they will all be turned on when the
name is specified. This allows, for example, all debug information for
-instruction scheduling to be enabled with ``-debug-type=InstrSched``, even if
+instruction scheduling to be enabled with ``-debug-only=InstrSched``, even if
the source lives in multiple files.
+For performance reasons, -debug-only is not available in optimized build
+(``--enable-optimized``) of LLVM.
+
The ``DEBUG_WITH_TYPE`` macro is also available for situations where you would
like to set ``DEBUG_TYPE``, but only for one specific ``DEBUG`` statement. It
takes an additional first parameter, which is the type to use. For example, the
llvm/ADT/ilist_node.h
^^^^^^^^^^^^^^^^^^^^^
-``ilist_node<T>`` implements a the forward and backward links that are expected
+``ilist_node<T>`` implements the forward and backward links that are expected
by the ``ilist<T>`` (and analogous containers) in the default manner.
``ilist_node<T>``\ s are meant to be embedded in the node type ``T``, usually
IntervalMap is a compact map for small keys and values. It maps key intervals
instead of single keys, and it will automatically coalesce adjacent intervals.
-When then map only contains a few intervals, they are stored in the map object
+When the map only contains a few intervals, they are stored in the map object
itself to avoid allocations.
The IntervalMap iterators are quite big, so they should not be passed around as
iteration over maps of pointers.
It is implemented by mapping from key to an index in a vector of key,value
-pairs. This provides fast lookup and iteration, but has two main drawbacks: The
-key is stored twice and it doesn't support removing elements.
+pairs. This provides fast lookup and iteration, but has two main drawbacks:
+the key is stored twice and removing elements takes linear time. If it is
+necessary to remove elements, it's best to remove them in bulk using
+``remove_if()``.
.. _dss_inteqclasses:
When you are done using the LLVM APIs, you should call ``llvm_shutdown()`` to
deallocate memory used for internal structures.
+
.. _managedstatic:
Lazy Initialization with ``ManagedStatic``
projects / oota-llvm.git / blobdiff