Address Reid's review feedback.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241889 91177308-0d34-0410-b5e6-96231b3b80d8

docs/LangRef.rst

@@ -5183,15 +5183,15 @@ none of the ``catchblock`` instructions are suitable for catching the
 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:
@@ -5212,6 +5212,7 @@ The ``catchendblock`` instruction has several restrictions:
    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:
 """"""""
@@ -5251,7 +5252,7 @@ Semantics:
 
 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:
@@ -5301,6 +5302,7 @@ Example:
 
 .. code-block:: llvm
 
+      cleanupret void unwind to caller
       cleanupret { i8*, i32 } %exn unwind label %continue
 
 .. _i_terminateblock:
@@ -5314,29 +5316,28 @@ Syntax:
 ::
 
       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:

lib/IR/Verifier.cpp

@@ -2408,8 +2408,8 @@ void Verifier::visitCallInst(CallInst &CI) {
 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!",

lib/Transforms/Instrumentation/MemorySanitizer.cpp

@@ -2654,23 +2654,27 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
   }
 
   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) {