From 7249ef04557cc6f9af7b6df93728683be3b65048 Mon Sep 17 00:00:00 2001
From: Dale Johannesen <dalej@apple.com>
Date: Fri, 2 Apr 2010 21:49:27 +0000
Subject: [PATCH] Skip debug info when looking for existing EH calls at the
 beginning of a block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100230 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/BasicBlock.h      |  6 ++++++
 lib/CodeGen/DwarfEHPrepare.cpp |  4 ++--
 lib/VMCore/BasicBlock.cpp      | 11 +++++++++++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/include/llvm/BasicBlock.h b/include/llvm/BasicBlock.h
index e358f91f90a..bf5874f6824 100644
--- a/include/llvm/BasicBlock.h
+++ b/include/llvm/BasicBlock.h
@@ -131,6 +131,12 @@ public:
   const Instruction* getFirstNonPHI() const {
     return const_cast<BasicBlock*>(this)->getFirstNonPHI();
   }
+
+  // Same as above, but also skip debug intrinsics.
+  Instruction* getFirstNonPHIOrDbg();
+  const Instruction* getFirstNonPHIOrDbg() const {
+    return const_cast<BasicBlock*>(this)->getFirstNonPHIOrDbg();
+  }
   
   /// removeFromParent - This method unlinks 'this' from the containing
   /// function, but does not delete it.
diff --git a/lib/CodeGen/DwarfEHPrepare.cpp b/lib/CodeGen/DwarfEHPrepare.cpp
index 8bae9edde72..7dbfd7d168b 100644
--- a/lib/CodeGen/DwarfEHPrepare.cpp
+++ b/lib/CodeGen/DwarfEHPrepare.cpp
@@ -661,7 +661,7 @@ bool DwarfEHPrepare::PromoteStackTemporaries() {
 /// the start of the basic block (unless there already is one, in which case
 /// the existing call is returned).
 Instruction *DwarfEHPrepare::CreateExceptionValueCall(BasicBlock *BB) {
-  Instruction *Start = BB->getFirstNonPHI();
+  Instruction *Start = BB->getFirstNonPHIOrDbg();
   // Is this a call to eh.exception?
   if (IntrinsicInst *CI = dyn_cast<IntrinsicInst>(Start))
     if (CI->getIntrinsicID() == Intrinsic::eh_exception)
@@ -681,7 +681,7 @@ Instruction *DwarfEHPrepare::CreateExceptionValueCall(BasicBlock *BB) {
 /// (creating it if necessary) at the start of the basic block (unless
 /// there already is a load, in which case the existing load is returned).
 Instruction *DwarfEHPrepare::CreateValueLoad(BasicBlock *BB) {
-  Instruction *Start = BB->getFirstNonPHI();
+  Instruction *Start = BB->getFirstNonPHIOrDbg();
   // Is this a load of the exception temporary?
   if (ExceptionValueVar)
     if (LoadInst* LI = dyn_cast<LoadInst>(Start))
diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp
index 16437bc1304..8ad53736c99 100644
--- a/lib/VMCore/BasicBlock.cpp
+++ b/lib/VMCore/BasicBlock.cpp
@@ -14,6 +14,7 @@
 #include "llvm/BasicBlock.h"
 #include "llvm/Constants.h"
 #include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
 #include "llvm/LLVMContext.h"
 #include "llvm/Type.h"
 #include "llvm/ADT/STLExtras.h"
@@ -136,6 +137,16 @@ Instruction* BasicBlock::getFirstNonPHI() {
   return &*i;
 }
 
+Instruction* BasicBlock::getFirstNonPHIOrDbg() {
+  BasicBlock::iterator i = begin();
+  // All valid basic blocks should have a terminator,
+  // which is not a PHINode. If we have an invalid basic
+  // block we'll get an assertion failure when dereferencing
+  // a past-the-end iterator.
+  while (isa<PHINode>(i) || isa<DbgInfoIntrinsic>(i)) ++i;
+  return &*i;
+}
+
 void BasicBlock::dropAllReferences() {
   for(iterator I = begin(), E = end(); I != E; ++I)
     I->dropAllReferences();