X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FIR%2FDebugInfo.cpp;h=4274d82d15875ac4166d5fbd9dbe4f09c21db954;hp=c7cdb80a6ace901717807e99ce1428f1b42823c4;hb=10c4265675595f84ce1ea4d53da342bc7b1add1a;hpb=e6f774e7ef1a11af39a6565465355db905f59d81

diff --git a/lib/IR/DebugInfo.cpp b/lib/IR/DebugInfo.cpp
index c7cdb80a6ac..4274d82d158 100644
--- a/lib/IR/DebugInfo.cpp
+++ b/lib/IR/DebugInfo.cpp
@@ -12,20 +12,22 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/DebugInfo.h"
+#include "llvm/IR/DebugInfo.h"
+#include "LLVMContextImpl.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/Module.h"
+#include "llvm/IR/ValueHandle.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Dwarf.h"
-#include "llvm/Support/ValueHandle.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 using namespace llvm::dwarf;
@@ -51,8 +53,8 @@ bool DIDescriptor::Verify() const {
 }
 
 static Value *getField(const MDNode *DbgNode, unsigned Elt) {
-  if (DbgNode == 0 || Elt >= DbgNode->getNumOperands())
-    return 0;
+  if (!DbgNode || Elt >= DbgNode->getNumOperands())
+    return nullptr;
   return DbgNode->getOperand(Elt);
 }
 
@@ -71,24 +73,24 @@ StringRef DIDescriptor::getStringField(unsigned Elt) const {
 }
 
 uint64_t DIDescriptor::getUInt64Field(unsigned Elt) const {
-  if (DbgNode == 0)
+  if (!DbgNode)
     return 0;
 
   if (Elt < DbgNode->getNumOperands())
-    if (ConstantInt *CI
-        = dyn_cast_or_null<ConstantInt>(DbgNode->getOperand(Elt)))
+    if (ConstantInt *CI =
+            dyn_cast_or_null<ConstantInt>(DbgNode->getOperand(Elt)))
       return CI->getZExtValue();
 
   return 0;
 }
 
 int64_t DIDescriptor::getInt64Field(unsigned Elt) const {
-  if (DbgNode == 0)
+  if (!DbgNode)
     return 0;
 
   if (Elt < DbgNode->getNumOperands())
-    if (ConstantInt *CI
-        = dyn_cast_or_null<ConstantInt>(DbgNode->getOperand(Elt)))
+    if (ConstantInt *CI =
+            dyn_cast_or_null<ConstantInt>(DbgNode->getOperand(Elt)))
       return CI->getSExtValue();
 
   return 0;
@@ -100,59 +102,98 @@ DIDescriptor DIDescriptor::getDescriptorField(unsigned Elt) const {
 }
 
 GlobalVariable *DIDescriptor::getGlobalVariableField(unsigned Elt) const {
-  if (DbgNode == 0)
-    return 0;
+  if (!DbgNode)
+    return nullptr;
 
   if (Elt < DbgNode->getNumOperands())
-      return dyn_cast_or_null<GlobalVariable>(DbgNode->getOperand(Elt));
-  return 0;
+    return dyn_cast_or_null<GlobalVariable>(DbgNode->getOperand(Elt));
+  return nullptr;
 }
 
 Constant *DIDescriptor::getConstantField(unsigned Elt) const {
-  if (DbgNode == 0)
-    return 0;
+  if (!DbgNode)
+    return nullptr;
 
   if (Elt < DbgNode->getNumOperands())
-      return dyn_cast_or_null<Constant>(DbgNode->getOperand(Elt));
-  return 0;
+    return dyn_cast_or_null<Constant>(DbgNode->getOperand(Elt));
+  return nullptr;
 }
 
 Function *DIDescriptor::getFunctionField(unsigned Elt) const {
-  if (DbgNode == 0)
-    return 0;
+  if (!DbgNode)
+    return nullptr;
 
   if (Elt < DbgNode->getNumOperands())
-      return dyn_cast_or_null<Function>(DbgNode->getOperand(Elt));
-  return 0;
+    return dyn_cast_or_null<Function>(DbgNode->getOperand(Elt));
+  return nullptr;
 }
 
 void DIDescriptor::replaceFunctionField(unsigned Elt, Function *F) {
-  if (DbgNode == 0)
+  if (!DbgNode)
     return;
 
   if (Elt < DbgNode->getNumOperands()) {
-    MDNode *Node = const_cast<MDNode*>(DbgNode);
+    MDNode *Node = const_cast<MDNode *>(DbgNode);
     Node->replaceOperandWith(Elt, F);
   }
 }
 
-unsigned DIVariable::getNumAddrElements() const {
-  return DbgNode->getNumOperands()-8;
+uint64_t DIVariable::getAddrElement(unsigned Idx) const {
+  DIDescriptor ComplexExpr = getDescriptorField(8);
+  if (Idx < ComplexExpr->getNumOperands())
+    if (auto *CI = dyn_cast_or_null<ConstantInt>(ComplexExpr->getOperand(Idx)))
+      return CI->getZExtValue();
+
+  assert(false && "non-existing complex address element requested");
+  return 0;
 }
 
 /// getInlinedAt - If this variable is inlined then return inline location.
-MDNode *DIVariable::getInlinedAt() const {
-  return getNodeField(DbgNode, 7);
+MDNode *DIVariable::getInlinedAt() const { return getNodeField(DbgNode, 7); }
+
+bool DIVariable::isVariablePiece() const {
+  return hasComplexAddress() && getAddrElement(0) == DIBuilder::OpPiece;
+}
+
+uint64_t DIVariable::getPieceOffset() const {
+  assert(isVariablePiece());
+  return getAddrElement(1);
+}
+
+uint64_t DIVariable::getPieceSize() const {
+  assert(isVariablePiece());
+  return getAddrElement(2);
 }
 
+/// Return the size reported by the variable's type.
+unsigned DIVariable::getSizeInBits(const DITypeIdentifierMap &Map) {
+  DIType Ty = getType().resolve(Map);
+  // Follow derived types until we reach a type that
+  // reports back a size.
+  while (Ty.isDerivedType() && !Ty.getSizeInBits()) {
+    DIDerivedType DT(&*Ty);
+    Ty = DT.getTypeDerivedFrom().resolve(Map);
+  }
+  assert(Ty.getSizeInBits() && "type with size 0");
+  return Ty.getSizeInBits();
+}
+
+
+
+
 //===----------------------------------------------------------------------===//
 // Predicates
 //===----------------------------------------------------------------------===//
 
+bool DIDescriptor::isSubroutineType() const {
+  return isCompositeType() && getTag() == dwarf::DW_TAG_subroutine_type;
+}
+
 /// isBasicType - Return true if the specified tag is legal for
 /// DIBasicType.
 bool DIDescriptor::isBasicType() const {
-  if (!DbgNode) return false;
+  if (!DbgNode)
+    return false;
   switch (getTag()) {
   case dwarf::DW_TAG_base_type:
   case dwarf::DW_TAG_unspecified_type:
@@ -164,7 +205,8 @@ bool DIDescriptor::isBasicType() const {
 
 /// isDerivedType - Return true if the specified tag is legal for DIDerivedType.
 bool DIDescriptor::isDerivedType() const {
-  if (!DbgNode) return false;
+  if (!DbgNode)
+    return false;
   switch (getTag()) {
   case dwarf::DW_TAG_typedef:
   case dwarf::DW_TAG_pointer_type:
@@ -187,7 +229,8 @@ bool DIDescriptor::isDerivedType() const {
 /// isCompositeType - Return true if the specified tag is legal for
 /// DICompositeType.
 bool DIDescriptor::isCompositeType() const {
-  if (!DbgNode) return false;
+  if (!DbgNode)
+    return false;
   switch (getTag()) {
   case dwarf::DW_TAG_array_type:
   case dwarf::DW_TAG_structure_type:
@@ -203,7 +246,8 @@ bool DIDescriptor::isCompositeType() const {
 
 /// isVariable - Return true if the specified tag is legal for DIVariable.
 bool DIDescriptor::isVariable() const {
-  if (!DbgNode) return false;
+  if (!DbgNode)
+    return false;
   switch (getTag()) {
   case dwarf::DW_TAG_auto_variable:
   case dwarf::DW_TAG_arg_variable:
@@ -231,26 +275,22 @@ bool DIDescriptor::isGlobalVariable() const {
                      getTag() == dwarf::DW_TAG_constant);
 }
 
-/// isUnspecifiedParmeter - Return true if the specified tag is
-/// DW_TAG_unspecified_parameters.
-bool DIDescriptor::isUnspecifiedParameter() const {
-  return DbgNode && getTag() == dwarf::DW_TAG_unspecified_parameters;
-}
-
 /// isScope - Return true if the specified tag is one of the scope
 /// related tag.
 bool DIDescriptor::isScope() const {
-  if (!DbgNode) return false;
+  if (!DbgNode)
+    return false;
   switch (getTag()) {
   case dwarf::DW_TAG_compile_unit:
   case dwarf::DW_TAG_lexical_block:
   case dwarf::DW_TAG_subprogram:
   case dwarf::DW_TAG_namespace:
+  case dwarf::DW_TAG_file_type:
     return true;
   default:
     break;
   }
-  return false;
+  return isType();
 }
 
 /// isTemplateTypeParameter - Return true if the specified tag is
@@ -286,13 +326,13 @@ bool DIDescriptor::isNameSpace() const {
 /// lexical block with an extra file.
 bool DIDescriptor::isLexicalBlockFile() const {
   return DbgNode && getTag() == dwarf::DW_TAG_lexical_block &&
-    (DbgNode->getNumOperands() == 3);
+         (DbgNode->getNumOperands() == 4);
 }
 
 /// isLexicalBlock - Return true if the specified tag is DW_TAG_lexical_block.
 bool DIDescriptor::isLexicalBlock() const {
   return DbgNode && getTag() == dwarf::DW_TAG_lexical_block &&
-    (DbgNode->getNumOperands() > 3);
+         (DbgNode->getNumOperands() > 3);
 }
 
 /// isSubrange - Return true if the specified tag is DW_TAG_subrange_type.
@@ -321,15 +361,9 @@ bool DIDescriptor::isImportedEntity() const {
 // Simple Descriptor Constructors and other Methods
 //===----------------------------------------------------------------------===//
 
-unsigned DIArray::getNumElements() const {
-  if (!DbgNode)
-    return 0;
-  return DbgNode->getNumOperands();
-}
-
 /// replaceAllUsesWith - Replace all uses of the MDNode used by this
 /// type with the one in the passed descriptor.
-void DIType::replaceAllUsesWith(DIDescriptor &D) {
+void DIDescriptor::replaceAllUsesWith(LLVMContext &VMContext, DIDescriptor D) {
 
   assert(DbgNode && "Trying to replace an unverified type!");
 
@@ -338,50 +372,32 @@ void DIType::replaceAllUsesWith(DIDescriptor &D) {
   // which, due to uniquing, has merged with the source. We shield clients from
   // this detail by allowing a value to be replaced with replaceAllUsesWith()
   // itself.
-  if (DbgNode != D) {
-    MDNode *Node = const_cast<MDNode*>(DbgNode);
-    const MDNode *DN = D;
-    const Value *V = cast_or_null<Value>(DN);
-    Node->replaceAllUsesWith(const_cast<Value*>(V));
-    MDNode::deleteTemporary(Node);
+  const MDNode *DN = D;
+  if (DbgNode == DN) {
+    SmallVector<Value*, 10> Ops(DbgNode->getNumOperands());
+    for (size_t i = 0; i != Ops.size(); ++i)
+      Ops[i] = DbgNode->getOperand(i);
+    DN = MDNode::get(VMContext, Ops);
   }
+
+  MDNode *Node = const_cast<MDNode *>(DbgNode);
+  const Value *V = cast_or_null<Value>(DN);
+  Node->replaceAllUsesWith(const_cast<Value *>(V));
+  MDNode::deleteTemporary(Node);
+  DbgNode = DN;
 }
 
 /// replaceAllUsesWith - Replace all uses of the MDNode used by this
 /// type with the one in D.
-void DIType::replaceAllUsesWith(MDNode *D) {
+void DIDescriptor::replaceAllUsesWith(MDNode *D) {
 
   assert(DbgNode && "Trying to replace an unverified type!");
-
-  // Since we use a TrackingVH for the node, its easy for clients to manufacture
-  // legitimate situations where they want to replaceAllUsesWith() on something
-  // which, due to uniquing, has merged with the source. We shield clients from
-  // this detail by allowing a value to be replaced with replaceAllUsesWith()
-  // itself.
-  if (DbgNode != D) {
-    MDNode *Node = const_cast<MDNode*>(DbgNode);
-    const MDNode *DN = D;
-    const Value *V = cast_or_null<Value>(DN);
-    Node->replaceAllUsesWith(const_cast<Value*>(V));
-    MDNode::deleteTemporary(Node);
-  }
-}
-
-/// isUnsignedDIType - Return true if type encoding is unsigned.
-bool DIType::isUnsignedDIType() {
-  DIDerivedType DTy(DbgNode);
-  if (DTy.Verify())
-    return DTy.getTypeDerivedFrom().isUnsignedDIType();
-
-  DIBasicType BTy(DbgNode);
-  if (BTy.Verify()) {
-    unsigned Encoding = BTy.getEncoding();
-    if (Encoding == dwarf::DW_ATE_unsigned ||
-        Encoding == dwarf::DW_ATE_unsigned_char ||
-        Encoding == dwarf::DW_ATE_boolean)
-      return true;
-  }
-  return false;
+  assert(DbgNode != D && "This replacement should always happen");
+  MDNode *Node = const_cast<MDNode *>(DbgNode);
+  const MDNode *DN = D;
+  const Value *V = cast_or_null<Value>(DN);
+  Node->replaceAllUsesWith(const_cast<Value *>(V));
+  MDNode::deleteTemporary(Node);
 }
 
 /// Verify - Verify that a compile unit is well formed.
@@ -394,7 +410,7 @@ bool DICompileUnit::Verify() const {
   if (getFilename().empty())
     return false;
 
-  return DbgNode->getNumOperands() == 13;
+  return DbgNode->getNumOperands() == 14;
 }
 
 /// Verify - Verify that an ObjC property is well formed.
@@ -406,12 +422,62 @@ bool DIObjCProperty::Verify() const {
   return DbgNode->getNumOperands() == 8;
 }
 
+/// Check if a field at position Elt of a MDNode is a MDNode.
+/// We currently allow an empty string and an integer.
+/// But we don't allow a non-empty string in a MDNode field.
+static bool fieldIsMDNode(const MDNode *DbgNode, unsigned Elt) {
+  // FIXME: This function should return true, if the field is null or the field
+  // is indeed a MDNode: return !Fld || isa<MDNode>(Fld).
+  Value *Fld = getField(DbgNode, Elt);
+  if (Fld && isa<MDString>(Fld) && !cast<MDString>(Fld)->getString().empty())
+    return false;
+  return true;
+}
+
+/// Check if a field at position Elt of a MDNode is a MDString.
+static bool fieldIsMDString(const MDNode *DbgNode, unsigned Elt) {
+  Value *Fld = getField(DbgNode, Elt);
+  return !Fld || isa<MDString>(Fld);
+}
+
+/// Check if a value can be a reference to a type.
+static bool isTypeRef(const Value *Val) {
+  return !Val ||
+         (isa<MDString>(Val) && !cast<MDString>(Val)->getString().empty()) ||
+         (isa<MDNode>(Val) && DIType(cast<MDNode>(Val)).isType());
+}
+
+/// Check if a field at position Elt of a MDNode can be a reference to a type.
+static bool fieldIsTypeRef(const MDNode *DbgNode, unsigned Elt) {
+  Value *Fld = getField(DbgNode, Elt);
+  return isTypeRef(Fld);
+}
+
+/// Check if a value can be a ScopeRef.
+static bool isScopeRef(const Value *Val) {
+  return !Val ||
+    (isa<MDString>(Val) && !cast<MDString>(Val)->getString().empty()) ||
+    // Not checking for Val->isScope() here, because it would work
+    // only for lexical scopes and not all subclasses of DIScope.
+    isa<MDNode>(Val);
+}
+
+/// Check if a field at position Elt of a MDNode can be a ScopeRef.
+static bool fieldIsScopeRef(const MDNode *DbgNode, unsigned Elt) {
+  Value *Fld = getField(DbgNode, Elt);
+  return isScopeRef(Fld);
+}
+
 /// Verify - Verify that a type descriptor is well formed.
 bool DIType::Verify() const {
   if (!isType())
     return false;
+  // Make sure Context @ field 2 is MDNode.
+  if (!fieldIsScopeRef(DbgNode, 2))
+    return false;
+
   // FIXME: Sink this into the various subclass verifies.
-  unsigned Tag = getTag();
+  uint16_t Tag = getTag();
   if (!isBasicType() && Tag != dwarf::DW_TAG_const_type &&
       Tag != dwarf::DW_TAG_volatile_type && Tag != dwarf::DW_TAG_pointer_type &&
       Tag != dwarf::DW_TAG_ptr_to_member_type &&
@@ -423,17 +489,17 @@ bool DIType::Verify() const {
       Tag != dwarf::DW_TAG_inheritance && Tag != dwarf::DW_TAG_friend &&
       getFilename().empty())
     return false;
+
   // DIType is abstract, it should be a BasicType, a DerivedType or
   // a CompositeType.
   if (isBasicType())
-    DIBasicType(DbgNode).Verify();
+    return DIBasicType(DbgNode).Verify();
   else if (isCompositeType())
-    DICompositeType(DbgNode).Verify();
+    return DICompositeType(DbgNode).Verify();
   else if (isDerivedType())
-    DIDerivedType(DbgNode).Verify();
+    return DIDerivedType(DbgNode).Verify();
   else
     return false;
-  return true;
 }
 
 /// Verify - Verify that a basic type descriptor is well formed.
@@ -443,6 +509,14 @@ bool DIBasicType::Verify() const {
 
 /// Verify - Verify that a derived type descriptor is well formed.
 bool DIDerivedType::Verify() const {
+  // Make sure DerivedFrom @ field 9 is TypeRef.
+  if (!fieldIsTypeRef(DbgNode, 9))
+    return false;
+  if (getTag() == dwarf::DW_TAG_ptr_to_member_type)
+    // Make sure ClassType @ field 10 is a TypeRef.
+    if (!fieldIsTypeRef(DbgNode, 10))
+      return false;
+
   return isDerivedType() && DbgNode->getNumOperands() >= 10 &&
          DbgNode->getNumOperands() <= 14;
 }
@@ -452,7 +526,21 @@ bool DICompositeType::Verify() const {
   if (!isCompositeType())
     return false;
 
-  return DbgNode->getNumOperands() >= 10 && DbgNode->getNumOperands() <= 14;
+  // Make sure DerivedFrom @ field 9 and ContainingType @ field 12 are TypeRef.
+  if (!fieldIsTypeRef(DbgNode, 9))
+    return false;
+  if (!fieldIsTypeRef(DbgNode, 12))
+    return false;
+
+  // Make sure the type identifier at field 14 is MDString, it can be null.
+  if (!fieldIsMDString(DbgNode, 14))
+    return false;
+
+  // A subroutine type can't be both & and &&.
+  if (isLValueReference() && isRValueReference())
+    return false;
+
+  return DbgNode->getNumOperands() == 15;
 }
 
 /// Verify - Verify that a subprogram descriptor is well formed.
@@ -460,6 +548,19 @@ bool DISubprogram::Verify() const {
   if (!isSubprogram())
     return false;
 
+  // Make sure context @ field 2 is a ScopeRef and type @ field 7 is a MDNode.
+  if (!fieldIsScopeRef(DbgNode, 2))
+    return false;
+  if (!fieldIsMDNode(DbgNode, 7))
+    return false;
+  // Containing type @ field 12.
+  if (!fieldIsTypeRef(DbgNode, 12))
+    return false;
+
+  // A subprogram can't be both & and &&.
+  if (isLValueReference() && isRValueReference())
+    return false;
+
   return DbgNode->getNumOperands() == 20;
 }
 
@@ -470,6 +571,15 @@ bool DIGlobalVariable::Verify() const {
 
   if (getDisplayName().empty())
     return false;
+  // Make sure context @ field 2 is an MDNode.
+  if (!fieldIsMDNode(DbgNode, 2))
+    return false;
+  // Make sure that type @ field 8 is a DITypeRef.
+  if (!fieldIsTypeRef(DbgNode, 8))
+    return false;
+  // Make sure StaticDataMemberDeclaration @ field 12 is MDNode.
+  if (!fieldIsMDNode(DbgNode, 12))
+    return false;
 
   return DbgNode->getNumOperands() == 13;
 }
@@ -479,7 +589,19 @@ bool DIVariable::Verify() const {
   if (!isVariable())
     return false;
 
-  return DbgNode->getNumOperands() >= 8;
+  // Make sure context @ field 1 is an MDNode.
+  if (!fieldIsMDNode(DbgNode, 1))
+    return false;
+  // Make sure that type @ field 5 is a DITypeRef.
+  if (!fieldIsTypeRef(DbgNode, 5))
+    return false;
+
+  // Variable without a complex expression.
+  if (DbgNode->getNumOperands() == 8)
+    return true;
+
+  // Make sure the complex expression is an MDNode.
+  return (DbgNode->getNumOperands() == 9 && fieldIsMDNode(DbgNode, 8));
 }
 
 /// Verify - Verify that a location descriptor is well formed.
@@ -498,9 +620,7 @@ bool DINameSpace::Verify() const {
 }
 
 /// \brief Retrieve the MDNode for the directory/file pair.
-MDNode *DIFile::getFileNode() const {
-  return getNodeField(DbgNode, 1);
-}
+MDNode *DIFile::getFileNode() const { return getNodeField(DbgNode, 1); }
 
 /// \brief Verify that the file descriptor is well formed.
 bool DIFile::Verify() const {
@@ -524,7 +644,7 @@ bool DILexicalBlock::Verify() const {
 
 /// \brief Verify that the file-scoped lexical block descriptor is well formed.
 bool DILexicalBlockFile::Verify() const {
-  return isLexicalBlockFile() && DbgNode->getNumOperands() == 3;
+  return isLexicalBlockFile() && DbgNode->getNumOperands() == 4;
 }
 
 /// \brief Verify that the template type parameter descriptor is well formed.
@@ -543,56 +663,61 @@ bool DIImportedEntity::Verify() const {
          (DbgNode->getNumOperands() == 4 || DbgNode->getNumOperands() == 5);
 }
 
-/// getOriginalTypeSize - If this type is derived from a base type then
-/// return base type size.
-uint64_t DIDerivedType::getOriginalTypeSize() const {
-  unsigned Tag = getTag();
-
-  if (Tag != dwarf::DW_TAG_member && Tag != dwarf::DW_TAG_typedef &&
-      Tag != dwarf::DW_TAG_const_type && Tag != dwarf::DW_TAG_volatile_type &&
-      Tag != dwarf::DW_TAG_restrict_type)
-    return getSizeInBits();
-
-  DIType BaseType = getTypeDerivedFrom();
-
-  // If this type is not derived from any type then take conservative approach.
-  if (!BaseType.isValid())
-    return getSizeInBits();
-
-  // If this is a derived type, go ahead and get the base type, unless it's a
-  // reference then it's just the size of the field. Pointer types have no need
-  // of this since they're a different type of qualification on the type.
-  if (BaseType.getTag() == dwarf::DW_TAG_reference_type ||
-      BaseType.getTag() == dwarf::DW_TAG_rvalue_reference_type)
-    return getSizeInBits();
-
-  if (BaseType.isDerivedType())
-    return DIDerivedType(BaseType).getOriginalTypeSize();
-
-  return BaseType.getSizeInBits();
-}
-
 /// getObjCProperty - Return property node, if this ivar is associated with one.
 MDNode *DIDerivedType::getObjCProperty() const {
   return getNodeField(DbgNode, 10);
 }
 
+MDString *DICompositeType::getIdentifier() const {
+  return cast_or_null<MDString>(getField(DbgNode, 14));
+}
+
+#ifndef NDEBUG
+static void VerifySubsetOf(const MDNode *LHS, const MDNode *RHS) {
+  for (unsigned i = 0; i != LHS->getNumOperands(); ++i) {
+    // Skip the 'empty' list (that's a single i32 0, rather than truly empty).
+    if (i == 0 && isa<ConstantInt>(LHS->getOperand(i)))
+      continue;
+    const MDNode *E = cast<MDNode>(LHS->getOperand(i));
+    bool found = false;
+    for (unsigned j = 0; !found && j != RHS->getNumOperands(); ++j)
+      found = E == RHS->getOperand(j);
+    assert(found && "Losing a member during member list replacement");
+  }
+}
+#endif
+
 /// \brief Set the array of member DITypes.
-void DICompositeType::setTypeArray(DIArray Elements, DIArray TParams) {
-  assert((!TParams || DbgNode->getNumOperands() == 14) &&
-         "If you're setting the template parameters this should include a slot "
-         "for that!");
+void DICompositeType::setArraysHelper(MDNode *Elements, MDNode *TParams) {
   TrackingVH<MDNode> N(*this);
-  N->replaceOperandWith(10, Elements);
+  if (Elements) {
+#ifndef NDEBUG
+    // Check that the new list of members contains all the old members as well.
+    if (const MDNode *El = cast_or_null<MDNode>(N->getOperand(10)))
+      VerifySubsetOf(El, Elements);
+#endif
+    N->replaceOperandWith(10, Elements);
+  }
   if (TParams)
     N->replaceOperandWith(13, TParams);
   DbgNode = N;
 }
 
+/// Generate a reference to this DIType. Uses the type identifier instead
+/// of the actual MDNode if possible, to help type uniquing.
+DIScopeRef DIScope::getRef() const {
+  if (!isCompositeType())
+    return DIScopeRef(*this);
+  DICompositeType DTy(DbgNode);
+  if (!DTy.getIdentifier())
+    return DIScopeRef(*this);
+  return DIScopeRef(DTy.getIdentifier());
+}
+
 /// \brief Set the containing type.
 void DICompositeType::setContainingType(DICompositeType ContainingType) {
   TrackingVH<MDNode> N(*this);
-  N->replaceOperandWith(12, ContainingType);
+  N->replaceOperandWith(12, ContainingType.getRef());
   DbgNode = N;
 }
 
@@ -622,7 +747,7 @@ bool DISubprogram::describes(const Function *F) {
 }
 
 unsigned DISubprogram::isOptimized() const {
-  assert (DbgNode && "Invalid subprogram descriptor!");
+  assert(DbgNode && "Invalid subprogram descriptor!");
   if (DbgNode->getNumOperands() == 15)
     return getUnsignedField(14);
   return 0;
@@ -640,6 +765,43 @@ Value *DITemplateValueParameter::getValue() const {
   return getField(DbgNode, 4);
 }
 
+// If the current node has a parent scope then return that,
+// else return an empty scope.
+DIScopeRef DIScope::getContext() const {
+
+  if (isType())
+    return DIType(DbgNode).getContext();
+
+  if (isSubprogram())
+    return DIScopeRef(DISubprogram(DbgNode).getContext());
+
+  if (isLexicalBlock())
+    return DIScopeRef(DILexicalBlock(DbgNode).getContext());
+
+  if (isLexicalBlockFile())
+    return DIScopeRef(DILexicalBlockFile(DbgNode).getContext());
+
+  if (isNameSpace())
+    return DIScopeRef(DINameSpace(DbgNode).getContext());
+
+  assert((isFile() || isCompileUnit()) && "Unhandled type of scope.");
+  return DIScopeRef(nullptr);
+}
+
+// If the scope node has a name, return that, else return an empty string.
+StringRef DIScope::getName() const {
+  if (isType())
+    return DIType(DbgNode).getName();
+  if (isSubprogram())
+    return DISubprogram(DbgNode).getName();
+  if (isNameSpace())
+    return DINameSpace(DbgNode).getName();
+  assert((isLexicalBlock() || isLexicalBlockFile() || isFile() ||
+          isCompileUnit()) &&
+         "Unhandled type of scope.");
+  return StringRef();
+}
+
 StringRef DIScope::getFilename() const {
   if (!DbgNode)
     return StringRef();
@@ -673,7 +835,6 @@ DIArray DICompileUnit::getSubprograms() const {
   return DIArray(getNodeField(DbgNode, 9));
 }
 
-
 DIArray DICompileUnit::getGlobalVariables() const {
   if (!DbgNode || DbgNode->getNumOperands() < 13)
     return DIArray();
@@ -688,6 +849,29 @@ DIArray DICompileUnit::getImportedEntities() const {
   return DIArray(getNodeField(DbgNode, 11));
 }
 
+/// copyWithNewScope - Return a copy of this location, replacing the
+/// current scope with the given one.
+DILocation DILocation::copyWithNewScope(LLVMContext &Ctx,
+                                        DILexicalBlockFile NewScope) {
+  SmallVector<Value *, 10> Elts;
+  assert(Verify());
+  for (unsigned I = 0; I < DbgNode->getNumOperands(); ++I) {
+    if (I != 2)
+      Elts.push_back(DbgNode->getOperand(I));
+    else
+      Elts.push_back(NewScope);
+  }
+  MDNode *NewDIL = MDNode::get(Ctx, Elts);
+  return DILocation(NewDIL);
+}
+
+/// computeNewDiscriminator - Generate a new discriminator value for this
+/// file and line location.
+unsigned DILocation::computeNewDiscriminator(LLVMContext &Ctx) {
+  std::pair<const char *, unsigned> Key(getFilename().data(), getLineNumber());
+  return ++Ctx.pImpl->DiscriminatorTable[Key];
+}
+
 /// fixupSubprogramName - Replace contains special characters used
 /// in a typical Objective-C names with '.' in a given string.
 static void fixupSubprogramName(DISubprogram Fn, SmallVectorImpl<char> &Out) {
@@ -738,8 +922,7 @@ DIVariable llvm::createInlinedVariable(MDNode *DV, MDNode *InlinedScope,
   SmallVector<Value *, 16> Elts;
   // Insert inlined scope as 7th element.
   for (unsigned i = 0, e = DV->getNumOperands(); i != e; ++i)
-    i == 7 ? Elts.push_back(InlinedScope) :
-             Elts.push_back(DV->getOperand(i));
+    i == 7 ? Elts.push_back(InlinedScope) : Elts.push_back(DV->getOperand(i));
   return DIVariable(MDNode::get(VMContext, Elts));
 }
 
@@ -748,12 +931,24 @@ DIVariable llvm::cleanseInlinedVariable(MDNode *DV, LLVMContext &VMContext) {
   SmallVector<Value *, 16> Elts;
   // Insert inlined scope as 7th element.
   for (unsigned i = 0, e = DV->getNumOperands(); i != e; ++i)
-    i == 7 ?
-      Elts.push_back(Constant::getNullValue(Type::getInt32Ty(VMContext))):
-      Elts.push_back(DV->getOperand(i));
+    i == 7 ? Elts.push_back(Constant::getNullValue(Type::getInt32Ty(VMContext)))
+           : Elts.push_back(DV->getOperand(i));
   return DIVariable(MDNode::get(VMContext, Elts));
 }
 
+
+/// getEntireVariable - Remove OpPiece exprs from the variable.
+DIVariable llvm::getEntireVariable(DIVariable DV) {
+  if (!DV.isVariablePiece())
+    return DV;
+
+  SmallVector<Value *, 8> Elts;
+  for (unsigned i = 0; i < 8; ++i)
+    Elts.push_back(DV->getOperand(i));
+
+  return DIVariable(MDNode::get(DV->getContext(), Elts));
+}
+
 /// getDISubprogram - Find subprogram that is enclosing this scope.
 DISubprogram llvm::getDISubprogram(const MDNode *Scope) {
   DIDescriptor D(Scope);
@@ -774,23 +969,42 @@ DICompositeType llvm::getDICompositeType(DIType T) {
   if (T.isCompositeType())
     return DICompositeType(T);
 
-  if (T.isDerivedType())
-    return getDICompositeType(DIDerivedType(T).getTypeDerivedFrom());
+  if (T.isDerivedType()) {
+    // This function is currently used by dragonegg and dragonegg does
+    // not generate identifier for types, so using an empty map to resolve
+    // DerivedFrom should be fine.
+    DITypeIdentifierMap EmptyMap;
+    return getDICompositeType(
+        DIDerivedType(T).getTypeDerivedFrom().resolve(EmptyMap));
+  }
 
   return DICompositeType();
 }
 
-/// isSubprogramContext - Return true if Context is either a subprogram
-/// or another context nested inside a subprogram.
-bool llvm::isSubprogramContext(const MDNode *Context) {
-  if (!Context)
-    return false;
-  DIDescriptor D(Context);
-  if (D.isSubprogram())
-    return true;
-  if (D.isType())
-    return isSubprogramContext(DIType(Context).getContext());
-  return false;
+/// Update DITypeIdentifierMap by going through retained types of each CU.
+DITypeIdentifierMap
+llvm::generateDITypeIdentifierMap(const NamedMDNode *CU_Nodes) {
+  DITypeIdentifierMap Map;
+  for (unsigned CUi = 0, CUe = CU_Nodes->getNumOperands(); CUi != CUe; ++CUi) {
+    DICompileUnit CU(CU_Nodes->getOperand(CUi));
+    DIArray Retain = CU.getRetainedTypes();
+    for (unsigned Ti = 0, Te = Retain.getNumElements(); Ti != Te; ++Ti) {
+      if (!Retain.getElement(Ti).isCompositeType())
+        continue;
+      DICompositeType Ty(Retain.getElement(Ti));
+      if (MDString *TypeId = Ty.getIdentifier()) {
+        // Definition has priority over declaration.
+        // Try to insert (TypeId, Ty) to Map.
+        std::pair<DITypeIdentifierMap::iterator, bool> P =
+            Map.insert(std::make_pair(TypeId, Ty));
+        // If TypeId already exists in Map and this is a definition, replace
+        // whatever we had (declaration or definition) with the definition.
+        if (!P.second && !Ty.isForwardDecl())
+          P.first->second = Ty;
+      }
+    }
+  }
+  return Map;
 }
 
 //===----------------------------------------------------------------------===//
@@ -804,10 +1018,21 @@ void DebugInfoFinder::reset() {
   TYs.clear();
   Scopes.clear();
   NodesSeen.clear();
+  TypeIdentifierMap.clear();
+  TypeMapInitialized = false;
+}
+
+void DebugInfoFinder::InitializeTypeMap(const Module &M) {
+  if (!TypeMapInitialized)
+    if (NamedMDNode *CU_Nodes = M.getNamedMetadata("llvm.dbg.cu")) {
+      TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
+      TypeMapInitialized = true;
+    }
 }
 
 /// processModule - Process entire module and collect debug info.
 void DebugInfoFinder::processModule(const Module &M) {
+  InitializeTypeMap(M);
   if (NamedMDNode *CU_Nodes = M.getNamedMetadata("llvm.dbg.cu")) {
     for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
       DICompileUnit CU(CU_Nodes->getOperand(i));
@@ -817,7 +1042,7 @@ void DebugInfoFinder::processModule(const Module &M) {
         DIGlobalVariable DIG(GVs.getElement(i));
         if (addGlobalVariable(DIG)) {
           processScope(DIG.getContext());
-          processType(DIG.getType());
+          processType(DIG.getType().resolve(TypeIdentifierMap));
         }
       }
       DIArray SPs = CU.getSubprograms();
@@ -829,38 +1054,45 @@ void DebugInfoFinder::processModule(const Module &M) {
       DIArray RetainedTypes = CU.getRetainedTypes();
       for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i)
         processType(DIType(RetainedTypes.getElement(i)));
-      // FIXME: We really shouldn't be bailing out after visiting just one CU
-      return;
+      DIArray Imports = CU.getImportedEntities();
+      for (unsigned i = 0, e = Imports.getNumElements(); i != e; ++i) {
+        DIImportedEntity Import = DIImportedEntity(Imports.getElement(i));
+        DIDescriptor Entity = Import.getEntity().resolve(TypeIdentifierMap);
+        if (Entity.isType())
+          processType(DIType(Entity));
+        else if (Entity.isSubprogram())
+          processSubprogram(DISubprogram(Entity));
+        else if (Entity.isNameSpace())
+          processScope(DINameSpace(Entity).getContext());
+      }
     }
   }
 }
 
 /// processLocation - Process DILocation.
-void DebugInfoFinder::processLocation(DILocation Loc) {
-  if (!Loc.Verify()) return;
-  DIDescriptor S(Loc.getScope());
-  if (S.isCompileUnit())
-    addCompileUnit(DICompileUnit(S));
-  else if (S.isSubprogram())
-    processSubprogram(DISubprogram(S));
-  else if (S.isLexicalBlock())
-    processLexicalBlock(DILexicalBlock(S));
-  else if (S.isLexicalBlockFile()) {
-    DILexicalBlockFile DBF = DILexicalBlockFile(S);
-    processLexicalBlock(DILexicalBlock(DBF.getScope()));
-  }
-  processLocation(Loc.getOrigLocation());
+void DebugInfoFinder::processLocation(const Module &M, DILocation Loc) {
+  if (!Loc)
+    return;
+  InitializeTypeMap(M);
+  processScope(Loc.getScope());
+  processLocation(M, Loc.getOrigLocation());
 }
 
 /// processType - Process DIType.
 void DebugInfoFinder::processType(DIType DT) {
   if (!addType(DT))
     return;
-  processScope(DT.getContext());
+  processScope(DT.getContext().resolve(TypeIdentifierMap));
   if (DT.isCompositeType()) {
     DICompositeType DCT(DT);
-    processType(DCT.getTypeDerivedFrom());
-    DIArray DA = DCT.getTypeArray();
+    processType(DCT.getTypeDerivedFrom().resolve(TypeIdentifierMap));
+    if (DT.isSubroutineType()) {
+      DITypeArray DTA = DISubroutineType(DT).getTypeArray();
+      for (unsigned i = 0, e = DTA.getNumElements(); i != e; ++i)
+        processType(DTA.getElement(i).resolve(TypeIdentifierMap));
+      return;
+    }
+    DIArray DA = DCT.getElements();
     for (unsigned i = 0, e = DA.getNumElements(); i != e; ++i) {
       DIDescriptor D = DA.getElement(i);
       if (D.isType())
@@ -870,7 +1102,7 @@ void DebugInfoFinder::processType(DIType DT) {
     }
   } else if (DT.isDerivedType()) {
     DIDerivedType DDT(DT);
-    processType(DDT.getTypeDerivedFrom());
+    processType(DDT.getTypeDerivedFrom().resolve(TypeIdentifierMap));
   }
 }
 
@@ -902,31 +1134,34 @@ void DebugInfoFinder::processScope(DIScope Scope) {
   }
 }
 
-/// processLexicalBlock
-void DebugInfoFinder::processLexicalBlock(DILexicalBlock LB) {
-  DIScope Context = LB.getContext();
-  if (Context.isLexicalBlock())
-    return processLexicalBlock(DILexicalBlock(Context));
-  else if (Context.isLexicalBlockFile()) {
-    DILexicalBlockFile DBF = DILexicalBlockFile(Context);
-    return processLexicalBlock(DILexicalBlock(DBF.getScope()));
-  }
-  else
-    return processSubprogram(DISubprogram(Context));
-}
-
 /// processSubprogram - Process DISubprogram.
 void DebugInfoFinder::processSubprogram(DISubprogram SP) {
   if (!addSubprogram(SP))
     return;
-  processScope(SP.getContext());
+  processScope(SP.getContext().resolve(TypeIdentifierMap));
   processType(SP.getType());
+  DIArray TParams = SP.getTemplateParams();
+  for (unsigned I = 0, E = TParams.getNumElements(); I != E; ++I) {
+    DIDescriptor Element = TParams.getElement(I);
+    if (Element.isTemplateTypeParameter()) {
+      DITemplateTypeParameter TType(Element);
+      processScope(TType.getContext().resolve(TypeIdentifierMap));
+      processType(TType.getType().resolve(TypeIdentifierMap));
+    } else if (Element.isTemplateValueParameter()) {
+      DITemplateValueParameter TVal(Element);
+      processScope(TVal.getContext().resolve(TypeIdentifierMap));
+      processType(TVal.getType().resolve(TypeIdentifierMap));
+    }
+  }
 }
 
 /// processDeclare - Process DbgDeclareInst.
-void DebugInfoFinder::processDeclare(const DbgDeclareInst *DDI) {
+void DebugInfoFinder::processDeclare(const Module &M,
+                                     const DbgDeclareInst *DDI) {
   MDNode *N = dyn_cast<MDNode>(DDI->getVariable());
-  if (!N) return;
+  if (!N)
+    return;
+  InitializeTypeMap(M);
 
   DIDescriptor DV(N);
   if (!DV.isVariable())
@@ -935,12 +1170,14 @@ void DebugInfoFinder::processDeclare(const DbgDeclareInst *DDI) {
   if (!NodesSeen.insert(DV))
     return;
   processScope(DIVariable(N).getContext());
-  processType(DIVariable(N).getType());
+  processType(DIVariable(N).getType().resolve(TypeIdentifierMap));
 }
 
-void DebugInfoFinder::processValue(const DbgValueInst *DVI) {
+void DebugInfoFinder::processValue(const Module &M, const DbgValueInst *DVI) {
   MDNode *N = dyn_cast<MDNode>(DVI->getVariable());
-  if (!N) return;
+  if (!N)
+    return;
+  InitializeTypeMap(M);
 
   DIDescriptor DV(N);
   if (!DV.isVariable())
@@ -948,12 +1185,13 @@ void DebugInfoFinder::processValue(const DbgValueInst *DVI) {
 
   if (!NodesSeen.insert(DV))
     return;
-  processType(DIVariable(N).getType());
+  processScope(DIVariable(N).getContext());
+  processType(DIVariable(N).getType().resolve(TypeIdentifierMap));
 }
 
 /// addType - Add type into Tys.
 bool DebugInfoFinder::addType(DIType DT) {
-  if (!DT.isValid())
+  if (!DT)
     return false;
 
   if (!NodesSeen.insert(DT))
@@ -965,9 +1203,8 @@ bool DebugInfoFinder::addType(DIType DT) {
 
 /// addCompileUnit - Add compile unit into CUs.
 bool DebugInfoFinder::addCompileUnit(DICompileUnit CU) {
-  if (!CU.Verify())
+  if (!CU)
     return false;
-
   if (!NodesSeen.insert(CU))
     return false;
 
@@ -977,7 +1214,7 @@ bool DebugInfoFinder::addCompileUnit(DICompileUnit CU) {
 
 /// addGlobalVariable - Add global variable into GVs.
 bool DebugInfoFinder::addGlobalVariable(DIGlobalVariable DIG) {
-  if (!DIDescriptor(DIG).isGlobalVariable())
+  if (!DIG)
     return false;
 
   if (!NodesSeen.insert(DIG))
@@ -989,7 +1226,7 @@ bool DebugInfoFinder::addGlobalVariable(DIGlobalVariable DIG) {
 
 // addSubprogram - Add subprgoram into SPs.
 bool DebugInfoFinder::addSubprogram(DISubprogram SP) {
-  if (!DIDescriptor(SP).isSubprogram())
+  if (!SP)
     return false;
 
   if (!NodesSeen.insert(SP))
@@ -1002,6 +1239,10 @@ bool DebugInfoFinder::addSubprogram(DISubprogram SP) {
 bool DebugInfoFinder::addScope(DIScope Scope) {
   if (!Scope)
     return false;
+  // FIXME: Ocaml binding generates a scope with no content, we treat it
+  // as null for now.
+  if (Scope->getNumOperands() == 0)
+    return false;
   if (!NodesSeen.insert(Scope))
     return false;
   Scopes.push_back(Scope);
@@ -1014,12 +1255,14 @@ bool DebugInfoFinder::addScope(DIScope Scope) {
 
 /// dump - Print descriptor to dbgs() with a newline.
 void DIDescriptor::dump() const {
-  print(dbgs()); dbgs() << '\n';
+  print(dbgs());
+  dbgs() << '\n';
 }
 
 /// print - Print descriptor.
 void DIDescriptor::print(raw_ostream &OS) const {
-  if (!DbgNode) return;
+  if (!DbgNode)
+    return;
 
   if (const char *Tag = dwarf::TagString(getTag()))
     OS << "[ " << Tag << " ]";
@@ -1081,7 +1324,8 @@ void DIEnumerator::printInternal(raw_ostream &OS) const {
 }
 
 void DIType::printInternal(raw_ostream &OS) const {
-  if (!DbgNode) return;
+  if (!DbgNode)
+    return;
 
   StringRef Res = getName();
   if (!Res.empty())
@@ -1089,13 +1333,11 @@ void DIType::printInternal(raw_ostream &OS) const {
 
   // TODO: Print context?
 
-  OS << " [line " << getLineNumber()
-     << ", size " << getSizeInBits()
-     << ", align " << getAlignInBits()
-     << ", offset " << getOffsetInBits();
+  OS << " [line " << getLineNumber() << ", size " << getSizeInBits()
+     << ", align " << getAlignInBits() << ", offset " << getOffsetInBits();
   if (isBasicType())
     if (const char *Enc =
-        dwarf::AttributeEncodingString(DIBasicType(DbgNode).getEncoding()))
+            dwarf::AttributeEncodingString(DIBasicType(DbgNode).getEncoding()))
       OS << ", enc " << Enc;
   OS << "]";
 
@@ -1103,6 +1345,8 @@ void DIType::printInternal(raw_ostream &OS) const {
     OS << " [private]";
   else if (isProtected())
     OS << " [protected]";
+  else if (isPublic())
+    OS << " [public]";
 
   if (isArtificial())
     OS << " [artificial]";
@@ -1118,6 +1362,12 @@ void DIType::printInternal(raw_ostream &OS) const {
     OS << " [vector]";
   if (isStaticMember())
     OS << " [static]";
+
+  if (isLValueReference())
+    OS << " [reference]";
+
+  if (isRValueReference())
+    OS << " [rvalue reference]";
 }
 
 void DIDerivedType::printInternal(raw_ostream &OS) const {
@@ -1127,7 +1377,7 @@ void DIDerivedType::printInternal(raw_ostream &OS) const {
 
 void DICompositeType::printInternal(raw_ostream &OS) const {
   DIType::printInternal(OS);
-  DIArray A = getTypeArray();
+  DIArray A = getElements();
   OS << " [" << A.getNumElements() << " elements]";
 }
 
@@ -1156,6 +1406,14 @@ void DISubprogram::printInternal(raw_ostream &OS) const {
     OS << " [private]";
   else if (isProtected())
     OS << " [protected]";
+  else if (isPublic())
+    OS << " [public]";
+
+  if (isLValueReference())
+    OS << " [reference]";
+
+  if (isRValueReference())
+    OS << " [rvalue reference]";
 
   StringRef Res = getName();
   if (!Res.empty())
@@ -1184,6 +1442,10 @@ void DIVariable::printInternal(raw_ostream &OS) const {
     OS << " [" << Res << ']';
 
   OS << " [line " << getLineNumber() << ']';
+
+  if (isVariablePiece())
+    OS << " [piece, size " << getPieceSize()
+       << ", offset " << getPieceOffset() << ']';
 }
 
 void DIObjCProperty::printInternal(raw_ostream &OS) const {
@@ -1191,16 +1453,15 @@ void DIObjCProperty::printInternal(raw_ostream &OS) const {
   if (!Name.empty())
     OS << " [" << Name << ']';
 
-  OS << " [line " << getLineNumber()
-     << ", properties " << getUnsignedField(6) << ']';
+  OS << " [line " << getLineNumber() << ", properties " << getUnsignedField(6)
+     << ']';
 }
 
 static void printDebugLoc(DebugLoc DL, raw_ostream &CommentOS,
                           const LLVMContext &Ctx) {
-  if (!DL.isUnknown()) {          // Print source line info.
+  if (!DL.isUnknown()) { // Print source line info.
     DIScope Scope(DL.getScope(Ctx));
-    assert(Scope.isScope() &&
-      "Scope of a DebugLoc should be a DIScope.");
+    assert(Scope.isScope() && "Scope of a DebugLoc should be a DIScope.");
     // Omit the directory, because it's likely to be long and uninteresting.
     CommentOS << Scope.getFilename();
     CommentOS << ':' << DL.getLine();
@@ -1229,3 +1490,101 @@ void DIVariable::printExtendedName(raw_ostream &OS) const {
     }
   }
 }
+
+/// Specialize constructor to make sure it has the correct type.
+template <> DIRef<DIScope>::DIRef(const Value *V) : Val(V) {
+  assert(isScopeRef(V) && "DIScopeRef should be a MDString or MDNode");
+}
+template <> DIRef<DIType>::DIRef(const Value *V) : Val(V) {
+  assert(isTypeRef(V) && "DITypeRef should be a MDString or MDNode");
+}
+
+/// Specialize getFieldAs to handle fields that are references to DIScopes.
+template <>
+DIScopeRef DIDescriptor::getFieldAs<DIScopeRef>(unsigned Elt) const {
+  return DIScopeRef(getField(DbgNode, Elt));
+}
+/// Specialize getFieldAs to handle fields that are references to DITypes.
+template <> DITypeRef DIDescriptor::getFieldAs<DITypeRef>(unsigned Elt) const {
+  return DITypeRef(getField(DbgNode, Elt));
+}
+
+/// Strip debug info in the module if it exists.
+/// To do this, we remove all calls to the debugger intrinsics and any named
+/// metadata for debugging. We also remove debug locations for instructions.
+/// Return true if module is modified.
+bool llvm::StripDebugInfo(Module &M) {
+
+  bool Changed = false;
+
+  // Remove all of the calls to the debugger intrinsics, and remove them from
+  // the module.
+  if (Function *Declare = M.getFunction("llvm.dbg.declare")) {
+    while (!Declare->use_empty()) {
+      CallInst *CI = cast<CallInst>(Declare->user_back());
+      CI->eraseFromParent();
+    }
+    Declare->eraseFromParent();
+    Changed = true;
+  }
+
+  if (Function *DbgVal = M.getFunction("llvm.dbg.value")) {
+    while (!DbgVal->use_empty()) {
+      CallInst *CI = cast<CallInst>(DbgVal->user_back());
+      CI->eraseFromParent();
+    }
+    DbgVal->eraseFromParent();
+    Changed = true;
+  }
+
+  for (Module::named_metadata_iterator NMI = M.named_metadata_begin(),
+         NME = M.named_metadata_end(); NMI != NME;) {
+    NamedMDNode *NMD = NMI;
+    ++NMI;
+    if (NMD->getName().startswith("llvm.dbg.")) {
+      NMD->eraseFromParent();
+      Changed = true;
+    }
+  }
+
+  for (Module::iterator MI = M.begin(), ME = M.end(); MI != ME; ++MI)
+    for (Function::iterator FI = MI->begin(), FE = MI->end(); FI != FE;
+         ++FI)
+      for (BasicBlock::iterator BI = FI->begin(), BE = FI->end(); BI != BE;
+           ++BI) {
+        if (!BI->getDebugLoc().isUnknown()) {
+          Changed = true;
+          BI->setDebugLoc(DebugLoc());
+        }
+      }
+
+  return Changed;
+}
+
+/// Return Debug Info Metadata Version by checking module flags.
+unsigned llvm::getDebugMetadataVersionFromModule(const Module &M) {
+  Value *Val = M.getModuleFlag("Debug Info Version");
+  if (!Val)
+    return 0;
+  return cast<ConstantInt>(Val)->getZExtValue();
+}
+
+llvm::DenseMap<const llvm::Function *, llvm::DISubprogram>
+llvm::makeSubprogramMap(const Module &M) {
+  DenseMap<const Function *, DISubprogram> R;
+
+  NamedMDNode *CU_Nodes = M.getNamedMetadata("llvm.dbg.cu");
+  if (!CU_Nodes)
+    return R;
+
+  for (MDNode *N : CU_Nodes->operands()) {
+    DICompileUnit CUNode(N);
+    DIArray SPs = CUNode.getSubprograms();
+    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
+      DISubprogram SP(SPs.getElement(i));
+      if (Function *F = SP.getFunction())
+        R.insert(std::make_pair(F, SP));
+    }
+  }
+  return R;
+}