[llvm] r235789 - [WinEH] Find correct cloned entry block for outlined handler functions.

[Andrew Kaylor]

Author: akaylor
Date: Fri Apr 24 18:10:38 2015
New Revision: 235789

URL: http://llvm.org/viewvc/llvm-project?rev=235789&view=rev
Log:
[WinEH] Find correct cloned entry block for outlined handler functions.

Modified:
    llvm/trunk/lib/CodeGen/WinEHPrepare.cpp

Modified: llvm/trunk/lib/CodeGen/WinEHPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/WinEHPrepare.cpp?rev=235789&r1=235788&r2=235789&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/WinEHPrepare.cpp (original)
+++ llvm/trunk/lib/CodeGen/WinEHPrepare.cpp Fri Apr 24 18:10:38 2015
@@ -1179,10 +1179,19 @@ bool WinEHPrepare::outlineHandler(Action
                             /*ModuleLevelChanges=*/false, Returns, "",
                             &OutlinedFunctionInfo, Director.get());
 
-  // Move all the instructions in the first cloned block into our entry block.
-  BasicBlock *FirstClonedBB = std::next(Function::iterator(Entry));
-  Entry->getInstList().splice(Entry->end(), FirstClonedBB->getInstList());
-  FirstClonedBB->eraseFromParent();
+  // Move all the instructions in the cloned "entry" block into our entry block.
+  // Depending on how the parent function was laid out, the block that will
+  // correspond to the outlined entry block may not be the first block in the
+  // list.  We can recognize it, however, as the cloned block which has no
+  // predecessors.  Any other block wouldn't have been cloned if it didn't
+  // have a predecessor which was also cloned.
+  Function::iterator  ClonedIt = std::next(Function::iterator(Entry));
+  while (!pred_empty(ClonedIt))
+    ++ClonedIt;
+  BasicBlock *ClonedEntryBB = ClonedIt;
+  assert(ClonedEntryBB);
+  Entry->getInstList().splice(Entry->end(), ClonedEntryBB->getInstList());
+  ClonedEntryBB->eraseFromParent();
 
   // Make sure we can identify the handler's personality later.
   addStubInvokeToHandlerIfNeeded(Handler, LPad->getPersonalityFn());