From: Jim Grosbach <grosbach@apple.com>
Date: Thu, 14 Jan 2010 21:38:31 +0000 (+0000)
Subject: Add comment explaining the necessity of r93456
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=86e69fa901ea0e04bc24ae3d8f757bccc84c10e6;p=oota-llvm.git

Add comment explaining the necessity of r93456

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93459 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index 8ea6dba5192..2b5fd2c9490 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -280,6 +280,11 @@ bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
   {
   case ExceptionHandling::SjLj:
     // SjLj piggy-backs on dwarf for this bit. The cleanups done apply to both
+    // Dwarf EH prepare needs to be run after SjLj prepare. Otherwise,
+    // catch info can get misplaced when a selector ends up more than one block
+    // removed from the parent invoke(s). This could happen when a landing
+    // pad is shared by multiple invokes and is also a target of a normal
+    // edge from elsewhere.
     PM.add(createSjLjEHPass(getTargetLowering()));
     PM.add(createDwarfEHPass(getTargetLowering(), OptLevel==CodeGenOpt::None));
     break;