in-flight exception.
If a ``nextaction`` label is not present, the instruction unwinds out of
-the function it is located in. The
-:ref:`personality function <personalityfn>` will look for an appropriate
-catch block in the caller.
+its parent function. The
+:ref:`personality function <personalityfn>` will continue processing
+exception handling actions in the caller.
Arguments:
""""""""""
The instruction optionally takes a label, ``nextaction``, indicating
-where control should transfer to if none of the constituent
+where control should transfer to if none of the preceding
``catchblock`` instructions are suitable for the in-flight exception.
Semantics:
catch block.
- A basic block that is not a catch-end block may not include a
'``catchendblock``' instruction.
+- Exactly one catch block may unwind to a ``catchendblock``.
Example:
""""""""
The '``catchret``' instruction ends the existing (in-flight) exception
whose unwinding was interrupted with a
-:ref:`catchblock <i_catchblock>` instruction and transfer control to
+:ref:`catchblock <i_catchblock>` instruction and transfers control to
``normal``.
Example:
.. code-block:: llvm
+ cleanupret void unwind to caller
cleanupret { i8*, i32 } %exn unwind label %continue
.. _i_terminateblock:
::
terminateblock [<args>*] unwind label <exception label>
+ terminateblock [<args>*] unwind to caller
Overview:
"""""""""
The '``terminateblock``' instruction is used by `LLVM's exception handling
system <ExceptionHandling.html#overview>`_ to specify that a basic block
-is a terminate block --- one where a personality routine attempts to transfer
-control to terminate the program.
+is a terminate block --- one where a personality routine may decide to
+terminate the program.
The ``args`` correspond to whatever information the personality
routine requires to know if this is an appropriate place to terminate the
program. Control is tranfered to the ``exception`` label if the
-``terminateblock`` is an appropriate handler for the in-flight exception.
-If the ``terminateblock`` is not an appropriate handler, execution of
-the program is terminated via
-:ref:`personality function <personalityfn>` specific means.
+personality routine decides not to terminate the program for the
+in-flight exception.
Arguments:
""""""""""
The instruction takes a list of arbitrary values which are interpreted
by the :ref:`personality function <personalityfn>`.
-The ``terminateblock`` must be provided an ``exception`` label to
+The ``terminateblock`` may be given an ``exception`` label to
transfer control to if the in-flight exception matches the ``args``.
Semantics:
void Verifier::visitInvokeInst(InvokeInst &II) {
VerifyCallSite(&II);
- // Verify that there is an exception block instruction is the first non-PHI
- // instruction of the 'unwind' destination.
+ // Verify that the first non-PHI instruction of the unwind destination is an
+ // exception handling instruction.
Assert(
II.getUnwindDest()->isEHBlock(),
"The unwind destination does not have an exception handling instruction!",
}
void visitCleanupBlockInst(CleanupBlockInst &I) {
- setShadow(&I, getCleanShadow(&I));
- setOrigin(&I, getCleanOrigin());
+ if (!I.getType()->isVoidTy()) {
+ setShadow(&I, getCleanShadow(&I));
+ setOrigin(&I, getCleanOrigin());
+ }
}
void visitCatchBlock(CatchBlockInst &I) {
- setShadow(&I, getCleanShadow(&I));
- setOrigin(&I, getCleanOrigin());
+ if (!I.getType()->isVoidTy()) {
+ setShadow(&I, getCleanShadow(&I));
+ setOrigin(&I, getCleanOrigin());
+ }
}
void visitTerminateBlock(TerminateBlockInst &I) {
- setShadow(&I, getCleanShadow(&I));
- setOrigin(&I, getCleanOrigin());
+ DEBUG(dbgs() << "TerminateBlock: " << I << "\n");
+ // Nothing to do here.
}
void visitCatchEndBlockInst(CatchEndBlockInst &I) {
- setShadow(&I, getCleanShadow(&I));
- setOrigin(&I, getCleanOrigin());
+ DEBUG(dbgs() << "CatchEndBlock: " << I << "\n");
+ // Nothing to do here.
}
void visitGetElementPtrInst(GetElementPtrInst &I) {