5 files changed, 31 insertions, 5 deletions
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 20fa0f4eab..3b903cdb09 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -182,6 +182,8 @@ bool LLParser::ValidateEndOfModule() {
   for (Module::iterator FI = M->begin(), FE = M->end(); FI != FE; )
     UpgradeCallsToIntrinsic(FI++); // must be post-increment, as we remove
 
+  UpgradeDebugInfo(*M);
+
   return false;
 }
 
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 2c95c920f8..ce3b7d163e 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -3152,6 +3152,7 @@ error_code BitcodeReader::MaterializeModule(Module *M) {
   for (unsigned I = 0, E = InstsWithTBAATag.size(); I < E; I++)
     UpgradeInstWithTBAATag(InstsWithTBAATag[I]);
 
+  UpgradeDebugInfo(*M);
   return error_code::success();
 }
 
diff --git a/lib/IR/AutoUpgrade.cpp b/lib/IR/AutoUpgrade.cpp
index 6f79919f24..32cfe278c7 100644
--- a/lib/IR/AutoUpgrade.cpp
+++ b/lib/IR/AutoUpgrade.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/AutoUpgrade.h"
+#include "llvm/DebugInfo.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
@@ -489,3 +490,12 @@ Value *llvm::UpgradeBitCastExpr(unsigned Opc, Constant *C, Type *DestTy) {
 
   return 0;
 }
+
+/// Check the debug info version number, if it is out-dated, drop the debug
+/// info. Return true if module is modified.
+bool llvm::UpgradeDebugInfo(Module &M) {
+  if (getDebugInfoVersionFromModule(M) == DEBUG_METADATA_VERSION)
+    return false;
+
+  return StripDebugInfo(M);
+}
diff --git a/lib/IR/DebugInfo.cpp b/lib/IR/DebugInfo.cpp
index 0c262024ff..68015b759a 100644
--- a/lib/IR/DebugInfo.cpp
+++ b/lib/IR/DebugInfo.cpp
@@ -1477,3 +1477,11 @@ bool llvm::StripDebugInfo(Module &M) {
 
   return Changed;
 }
+
+/// Return Debug Info Version by checking module flags.
+unsigned llvm::getDebugInfoVersionFromModule(const Module &M) {
+  Value *Val = M.getModuleFlag("Debug Info Version");
+  if (!Val)
+    return 0;
+  return cast<ConstantInt>(Val)->getZExtValue();
+}
diff --git a/lib/IR/Module.cpp b/lib/IR/Module.cpp
index 3dd1f7e810..4f240c783e 100644
--- a/lib/IR/Module.cpp
+++ b/lib/IR/Module.cpp
@@ -318,11 +318,16 @@ getModuleFlagsMetadata(SmallVectorImpl<ModuleFlagEntry> &Flags) const {
 
   for (unsigned i = 0, e = ModFlags->getNumOperands(); i != e; ++i) {
     MDNode *Flag = ModFlags->getOperand(i);
-    ConstantInt *Behavior = cast<ConstantInt>(Flag->getOperand(0));
-    MDString *Key = cast<MDString>(Flag->getOperand(1));
-    Value *Val = Flag->getOperand(2);
-    Flags.push_back(ModuleFlagEntry(ModFlagBehavior(Behavior->getZExtValue()),
-                                    Key, Val));
+    if (Flag->getNumOperands() >= 3 && isa<ConstantInt>(Flag->getOperand(0)) &&
+        isa<MDString>(Flag->getOperand(1))) {
+      // Check the operands of the MDNode before accessing the operands.
+      // The verifier will actually catch these failures.
+      ConstantInt *Behavior = cast<ConstantInt>(Flag->getOperand(0));
+      MDString *Key = cast<MDString>(Flag->getOperand(1));
+      Value *Val = Flag->getOperand(2);
+      Flags.push_back(ModuleFlagEntry(ModFlagBehavior(Behavior->getZExtValue()),
+                                      Key, Val));
+    }
   }
 }