New EH representation for MSVC compatibility

This introduces new instructions neccessary to implement MSVC-compatible
exception handling support.  Most of the middle-end and none of the
back-end haven't been audited or updated to take them into account.

Differential Revision: http://reviews.llvm.org/D11097

llvm-svn: 243766

1 files changed, 12 insertions, 1 deletions

diff --git a/llvm/lib/IR/BasicBlock.cpp b/llvm/lib/IR/BasicBlock.cpp
index 0a0449434a7..b5671a66f04 100644
--- a/llvm/lib/IR/BasicBlock.cpp
+++ b/llvm/lib/IR/BasicBlock.cpp
@@ -197,7 +197,7 @@ BasicBlock::iterator BasicBlock::getFirstInsertionPt() {
     return end();
 
   iterator InsertPt = FirstNonPHI;
-  if (isa<LandingPadInst>(InsertPt)) ++InsertPt;
+  if (InsertPt->isEHPad()) ++InsertPt;
   return InsertPt;
 }
 
@@ -333,6 +333,17 @@ void BasicBlock::removePredecessor(BasicBlock *Pred,
   }
 }
 
+bool BasicBlock::canSplitPredecessors() const {
+  const Instruction *FirstNonPHI = getFirstNonPHI();
+  if (isa<LandingPadInst>(FirstNonPHI))
+    return true;
+  // This is perhaps a little conservative because constructs like
+  // CleanupBlockInst are pretty easy to split.  However, SplitBlockPredecessors
+  // cannot handle such things just yet.
+  if (FirstNonPHI->isEHPad())
+    return false;
+  return true;
+}
 
 /// This splits a basic block into two at the specified
 /// instruction.  Note that all instructions BEFORE the specified iterator stay