semantically equivalent to composing the caller's deoptimization
continuation after the callee's deoptimization continuation.
+.. _ob_funclet:
+
Funclet Operand Bundles
^^^^^^^^^^^^^^^^^^^^^^^
``"funclet"`` operand bundle attached to a call site and it must have
exactly one bundle operand.
+If any funclet EH pads have been "entered" but not "exited" (per the
+`description in the EH doc\ <ExceptionHandling.html#wineh-constraints>`_),
+it is undefined behavior to execute a ``call`` or ``invoke`` which:
+
+* does not have a ``"funclet"`` bundle and is not a ``call`` to a nounwind
+ intrinsic, or
+* has a ``"funclet"`` bundle whose operand is not the most-recently-entered
+ not-yet-exited funclet EH pad.
+
+Similarly, if no funclet EH pads have been entered-but-not-yet-exited,
+executing a ``call`` or ``invoke`` with a ``"funclet"`` bundle is undefined behavior.
+
.. _moduleasm:
Module-Level Inline Assembly
``catchswitch`` instruction. If the ``catchswitch`` is not inside a funclet,
this operand may be the token ``none``.
-The ``default`` argument is the label of another basic block beginning with a
-"pad" instruction, one of ``cleanuppad`` or ``catchswitch``.
+The ``default`` argument is the label of another basic block beginning with
+either a ``cleanuppad`` or ``catchswitch`` instruction. This unwind destination
+must be a legal target with respect to the ``parent`` links, as described in
+the `exception handling documentation\ <ExceptionHandling.html#wineh-constraints>`_.
-The ``handlers`` are a list of successor blocks that each begin with a
+The ``handlers`` are a nonempty list of successor blocks that each begin with a
:ref:`catchpad <i_catchpad>` instruction.
Semantics:
The meaning of the tokens produced and consumed by ``catchpad`` and other "pad"
instructions is described in the
-`Windows exception handling documentation <ExceptionHandling.html#wineh>`.
+`Windows exception handling documentation\ <ExceptionHandling.html#wineh>`_.
-Executing a ``catchpad`` instruction constitutes "entering" that pad.
-The pad may then be "exited" in one of three ways:
-
-1) explicitly via a ``catchret`` that consumes it. Executing such a ``catchret``
- is undefined behavior if any descendant pads have been entered but not yet
- exited.
-2) implicitly via a call (which unwinds all the way to the current function's caller),
- or via a ``catchswitch`` or a ``cleanupret`` that unwinds to caller.
-3) implicitly via an unwind edge whose destination EH pad isn't a descendant of
- the ``catchpad``. When the ``catchpad`` is exited in this manner, it is
- undefined behavior if the destination EH pad has a parent which is not an
- ancestor of the ``catchpad`` being exited.
+When a ``catchpad`` has been "entered" but not yet "exited" (as
+described in the `EH documentation\ <ExceptionHandling.html#wineh-constraints>`_),
+it is undefined behavior to execute a :ref:`call <i_call>` or :ref:`invoke <i_invoke>`
+that does not carry an appropriate :ref:`"funclet" bundle <ob_funclet>`.
Example:
""""""""
code to, for example, destroy the active exception. Control then transfers to
``normal``.
-The ``token`` argument must be a token produced by a dominating ``catchpad``
-instruction. The ``catchret`` destroys the physical frame established by
-``catchpad``, so executing multiple returns on the same token without
-re-executing the ``catchpad`` will result in undefined behavior.
-See :ref:`catchpad <i_catchpad>` for more details.
+The ``token`` argument must be a token produced by a ``catchpad`` instruction.
+If the specified ``catchpad`` is not the most-recently-entered not-yet-exited
+funclet pad (as described in the `EH documentation\ <ExceptionHandling.html#wineh-constraints>`_),
+the ``catchret``'s behavior is undefined.
Example:
""""""""
The '``cleanupret``' instruction requires one argument, which indicates
which ``cleanuppad`` it exits, and must be a :ref:`cleanuppad <i_cleanuppad>`.
-It also has an optional successor, ``continue``.
+If the specified ``cleanuppad`` is not the most-recently-entered not-yet-exited
+funclet pad (as described in the `EH documentation\ <ExceptionHandling.html#wineh-constraints>`_),
+the ``cleanupret``'s behavior is undefined.
+
+The '``cleanupret``' instruction also has an optional successor, ``continue``,
+which must be the label of another basic block beginning with either a
+``cleanuppad`` or ``catchswitch`` instruction. This unwind destination must
+be a legal target with respect to the ``parent`` links, as described in the
+`exception handling documentation\ <ExceptionHandling.html#wineh-constraints>`_.
Semantics:
""""""""""
:ref:`cleanuppad <i_cleanuppad>` it transferred control to has ended.
It transfers control to ``continue`` or unwinds out of the function.
-The unwind destination ``continue``, if present, must be an EH pad
-whose parent is either ``none`` or an ancestor of the ``cleanuppad``
-being returned from. This constitutes an exceptional exit from all
-ancestors of the completed ``cleanuppad``, up to but not including
-the parent of ``continue``.
-See :ref:`cleanuppad <i_cleanuppad>` for more details.
-
Example:
""""""""
- A basic block that is not a cleanup block may not include a
'``cleanuppad``' instruction.
-Executing a ``cleanuppad`` instruction constitutes "entering" that pad.
-The pad may then be "exited" in one of three ways:
-
-1) explicitly via a ``cleanupret`` that consumes it. Executing such a ``cleanupret``
- is undefined behavior if any descendant pads have been entered but not yet
- exited.
-2) implicitly via a call (which unwinds all the way to the current function's caller),
- or via a ``catchswitch`` or a ``cleanupret`` that unwinds to caller.
-3) implicitly via an unwind edge whose destination EH pad isn't a descendant of
- the ``cleanuppad``. When the ``cleanuppad`` is exited in this manner, it is
- undefined behavior if the destination EH pad has a parent which is not an
- ancestor of the ``cleanuppad`` being exited.
+When a ``cleanuppad`` has been "entered" but not yet "exited" (as
+described in the `EH documentation\ <ExceptionHandling.html#wineh-constraints>`_),
+it is undefined behavior to execute a :ref:`call <i_call>` or :ref:`invoke <i_invoke>`
+that does not carry an appropriate :ref:`"funclet" bundle <ob_funclet>`.
It is undefined behavior for the ``cleanuppad`` to exit via an unwind edge which
does not transitively unwind to the same destination as a constituent
projects / oota-llvm.git / blobdiff