diff --git a/lib/CodeGen/CGBlocks.cpp b/lib/CodeGen/CGBlocks.cpp
index 41b49c7..8ed1f90 100644
--- a/lib/CodeGen/CGBlocks.cpp
+++ b/lib/CodeGen/CGBlocks.cpp
@@ -218,9 +218,12 @@
 
         llvm::Value* Addr = Builder.CreateStructGEP(V, i+5, "tmp");
         NoteForHelper[helpersize].index = i+5;
-        NoteForHelper[helpersize].RequiresCopying = BlockRequiresCopying(VD->getType());
+        NoteForHelper[helpersize].RequiresCopying
+          = BlockRequiresCopying(VD->getType());
         NoteForHelper[helpersize].flag
-          = VD->getType()->isBlockPointerType() ? BLOCK_FIELD_IS_BLOCK : BLOCK_FIELD_IS_OBJECT;
+          = (VD->getType()->isBlockPointerType()
+             ? BLOCK_FIELD_IS_BLOCK
+             : BLOCK_FIELD_IS_OBJECT);
 
         if (LocalDeclMap[VD]) {
           if (BDRE->isByRef()) {
@@ -386,6 +389,10 @@
   return GenericExtendedBlockLiteralType;
 }
 
+bool BlockFunction::BlockRequiresCopying(QualType Ty) {
+  return CGM.BlockRequiresCopying(Ty);
+}
+
 RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr* E) {
   const BlockPointerType *BPT =
     E->getCallee()->getType()->getAs<BlockPointerType>();
diff --git a/lib/CodeGen/CGBlocks.h b/lib/CodeGen/CGBlocks.h
index 6309e1d..8557d1f 100644
--- a/lib/CodeGen/CGBlocks.h
+++ b/lib/CodeGen/CGBlocks.h
@@ -115,6 +115,16 @@
     PtrToInt8Ty = llvm::PointerType::getUnqual(
                 llvm::Type::getInt8Ty(M.getContext()));
   }
+
+  bool BlockRequiresCopying(QualType Ty) {
+    if (Ty->isBlockPointerType())
+      return true;
+    if (getContext().isObjCNSObjectType(Ty))
+      return true;
+    if (Ty->isObjCObjectPointerType())
+      return true;
+    return false;
+  }
 };
 
 class BlockFunction : public BlockBase {
@@ -219,15 +229,7 @@
   llvm::Value *getBlockObjectDispose();
   void BuildBlockRelease(llvm::Value *DeclPtr, int flag = BLOCK_FIELD_IS_BYREF);
 
-  bool BlockRequiresCopying(QualType Ty) {
-    if (Ty->isBlockPointerType())
-      return true;
-    if (getContext().isObjCNSObjectType(Ty))
-      return true;
-    if (Ty->isObjCObjectPointerType())
-      return true;
-    return false;
-  }
+  bool BlockRequiresCopying(QualType Ty);
 };
 
 }  // end namespace CodeGen
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 1bd0918..6f5bb15 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -918,7 +918,139 @@
     return;
 
   llvm::DICompileUnit Unit = getOrCreateCompileUnit(Decl->getLocation());
-  llvm::DIType Ty = getOrCreateType(Decl->getType(), Unit);
+  QualType Type = Decl->getType();
+  llvm::DIType Ty = getOrCreateType(Type, Unit);
+  if (Decl->hasAttr<BlocksAttr>()) {
+    llvm::DICompileUnit DefUnit;
+    unsigned Tag = llvm::dwarf::DW_TAG_structure_type;
+
+    llvm::SmallVector<llvm::DIDescriptor, 5> EltTys;
+
+    llvm::DIType FieldTy;
+
+    QualType FType;
+    uint64_t FieldSize, FieldOffset;
+    unsigned FieldAlign;
+
+    llvm::DIArray Elements;
+    llvm::DIType EltTy;
+    
+    // Build up structure for the byref.  See BuildByRefType.
+    FieldOffset = 0;
+    FType = M->getContext().getPointerType(M->getContext().VoidTy);
+    FieldTy = CGDebugInfo::getOrCreateType(FType, Unit);
+    FieldSize = M->getContext().getTypeSize(FType);
+    FieldAlign = M->getContext().getTypeAlign(FType);
+    FieldTy = DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_member, Unit,
+                                             "__isa", DefUnit,
+                                             0, FieldSize, FieldAlign,
+                                             FieldOffset, 0, FieldTy);
+    EltTys.push_back(FieldTy);
+    FieldOffset += FieldSize;
+
+    FType = M->getContext().getPointerType(M->getContext().VoidTy);
+    FieldTy = CGDebugInfo::getOrCreateType(FType, Unit);
+    FieldSize = M->getContext().getTypeSize(FType);
+    FieldAlign = M->getContext().getTypeAlign(FType);
+    FieldTy = DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_member, Unit,
+                                             "__forwarding", DefUnit,
+                                             0, FieldSize, FieldAlign,
+                                             FieldOffset, 0, FieldTy);
+    EltTys.push_back(FieldTy);
+    FieldOffset += FieldSize;
+
+    FType = M->getContext().getFixedWidthIntType(32, true); // Int32Ty;
+    FieldTy = CGDebugInfo::getOrCreateType(FType, Unit);
+    FieldSize = M->getContext().getTypeSize(FType);
+    FieldAlign = M->getContext().getTypeAlign(FType);
+    FieldTy = DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_member, Unit,
+                                             "__flags", DefUnit,
+                                             0, FieldSize, FieldAlign,
+                                             FieldOffset, 0, FieldTy);
+    EltTys.push_back(FieldTy);
+    FieldOffset += FieldSize;
+
+    FType = M->getContext().getFixedWidthIntType(32, true); // Int32Ty;
+    FieldTy = CGDebugInfo::getOrCreateType(FType, Unit);
+    FieldSize = M->getContext().getTypeSize(FType);
+    FieldAlign = M->getContext().getTypeAlign(FType);
+    FieldTy = DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_member, Unit,
+                                             "__size", DefUnit,
+                                             0, FieldSize, FieldAlign,
+                                             FieldOffset, 0, FieldTy);
+    EltTys.push_back(FieldTy);
+    FieldOffset += FieldSize;
+    
+    bool HasCopyAndDispose = M->BlockRequiresCopying(Type);
+    if (HasCopyAndDispose) {
+      FType = M->getContext().getPointerType(M->getContext().VoidTy);
+      FieldTy = CGDebugInfo::getOrCreateType(FType, Unit);
+      FieldSize = M->getContext().getTypeSize(FType);
+      FieldAlign = M->getContext().getTypeAlign(FType);
+      FieldTy = DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_member, Unit,
+                                               "__copy_helper", DefUnit,
+                                               0, FieldSize, FieldAlign,
+                                               FieldOffset, 0, FieldTy);
+      EltTys.push_back(FieldTy);
+      FieldOffset += FieldSize;
+
+      FType = M->getContext().getPointerType(M->getContext().VoidTy);
+      FieldTy = CGDebugInfo::getOrCreateType(FType, Unit);
+      FieldSize = M->getContext().getTypeSize(FType);
+      FieldAlign = M->getContext().getTypeAlign(FType);
+      FieldTy = DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_member, Unit,
+                                               "__destroy_helper", DefUnit,
+                                               0, FieldSize, FieldAlign,
+                                               FieldOffset, 0, FieldTy);
+      EltTys.push_back(FieldTy);
+      FieldOffset += FieldSize;
+    }
+    
+    unsigned Align = M->getContext().getDeclAlignInBytes(Decl);
+    if (Align > M->getContext().Target.getPointerAlign(0) / 8) {
+      unsigned AlignedOffsetInBytes
+        = llvm::RoundUpToAlignment(FieldOffset, Align);
+      unsigned NumPaddingBytes
+        = AlignedOffsetInBytes = FieldOffset;
+
+      if (NumPaddingBytes > 0) {
+        llvm::APInt pad(32, NumPaddingBytes);
+        FType = M->getContext().getConstantArrayType(M->getContext().CharTy,
+                                                     pad, ArrayType::Normal, 0);
+        FieldTy = CGDebugInfo::getOrCreateType(FType, Unit);
+        FieldSize = M->getContext().getTypeSize(FType);
+        FieldAlign = M->getContext().getTypeAlign(FType);
+        FieldTy = DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_member,
+                                                 Unit, "", DefUnit,
+                                                 0, FieldSize, FieldAlign,
+                                                 FieldOffset, 0, FieldTy);
+        EltTys.push_back(FieldTy);
+        FieldOffset += FieldSize;
+      }
+    }
+
+    FType = Type;
+    FieldTy = CGDebugInfo::getOrCreateType(FType, Unit);
+    FieldSize = M->getContext().getTypeSize(FType);
+    FieldAlign = M->getContext().getTypeAlign(FType);
+    std::string Name = Decl->getNameAsString();
+    
+    FieldTy = DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_member, Unit,
+                                             Name, DefUnit,
+                                             0, FieldSize, FieldAlign,
+                                             FieldOffset, 0, FieldTy);
+    EltTys.push_back(FieldTy);
+    FieldOffset += FieldSize;
+
+    Elements = DebugFactory.GetOrCreateArray(EltTys.data(), EltTys.size());
+
+    unsigned Flags = llvm::DIType::FlagBlockByrefStruct;
+
+    Ty = DebugFactory.CreateCompositeType(Tag, Unit, "",
+                                          llvm::DICompileUnit(),
+                                          0, FieldOffset, 0, 0, Flags,
+                                          llvm::DIType(), Elements);
+  }
 
   // Get location information.
   SourceManager &SM = M->getContext().getSourceManager();
diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index 31e74f0..d1f6b27 100644
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -213,8 +213,9 @@
 ///        void *__forwarding;
 ///        int32_t __flags;
 ///        int32_t __size;
-///        void *__copy_helper;
-///        void *__destroy_helper;
+///        void *__copy_helper;       // only if needed
+///        void *__destroy_helper;    // only if needed
+///        char padding[X];           // only if needed
 ///        T x;
 ///      } x
 ///
@@ -390,21 +391,6 @@
     DI->setLocation(D.getLocation());
     if (Target.useGlobalsForAutomaticVariables()) {
       DI->EmitGlobalVariable(static_cast<llvm::GlobalVariable *>(DeclPtr), &D);
-    } else if (isByRef) {
-      // FIXME: This code is broken and will not emit debug info for the
-      // variable. The right way to do this would be to tell LLVM that this is a
-      // byref pointer, and what the offset is. Unfortunately, right now it's
-      // not possible unless we create a DIType that corresponds to the byref
-      // struct.
-      /*
-      llvm::Value *Loc;
-      bool needsCopyDispose = BlockRequiresCopying(Ty);
-      Loc = Builder.CreateStructGEP(DeclPtr, 1, "forwarding");
-      Loc = Builder.CreateLoad(Loc, false);
-      Loc = Builder.CreateBitCast(Loc, DeclPtr->getType());
-      Loc = Builder.CreateStructGEP(Loc, needsCopyDispose*2+4, "x");
-      DI->EmitDeclareOfAutoVariable(&D, Loc, Builder);
-      */
     } else
       DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder);
   }