[OpenCL] Pipe type support

[pxli168]

Summary

Support for OpenCL 2.0 pipe type.
This is a bug-fix version for bader's patch reviews.llvm.org/D14441

[bader]

include/clang/AST/Type.h

5020

Xuili, could you apply the comments left by Pekka and Anastasia for the previous version of the patch (http://reviews.llvm.org/D14441). Most of the comments are valid for this patch also.
Particularly for this line Anastasia asked "Any reason for an empty comment line here?". I think it's not necessary.

[pxli168]

include/clang/AST/Type.h

5020

I have made some changes to their comments, but I found something still left here. I will fix them.

[pxli168]

Apply comment form http://reviews.llvm.org/D14441.

[Anastasia]

lib/AST/ASTContext.cpp

3147

I don't think this comment is much related here - a copy-paste issue perhaps? But I see this is replicated elsewhere.

As mentioned in comment of http://reviews.llvm.org/D14441, I think we might want to look at refactoring the code that handles wrapper types in Clang. However, this shouldn't prevent this patch from being committed.

lib/CodeGen/CGOpenCLRuntime.cpp

108

Should there be any indication of pipe element type or at least its size? I.e should we differentiate between 'pipe char' or 'pipe int' in IR?

Perhaps, it doesn't have to be a part of this commit, but it would still be useful to understand.

lib/CodeGen/CodeGenFunction.cpp

565

acess -> access
OCL -> OpenCL

lib/Sema/TreeTransform.h

5352

Not clear why the namespace is being added here? i. e. seems to be old code.

test/CodeGenOpenCL/pipe_types.cl

16

Do we need to check reserve_id_t in every test? I feel like having it once would be enough.

test/SemaOpenCL/pipes-1.2-negative.cl

2

Could we add tests for checking CL2.0 pipes diagnostics added in this patch?

[pxli168]

lib/CodeGen/CGOpenCLRuntime.cpp

108

There is one for the element size in the pipe related built-ins. But the built-in part refined the some of the built-in functions.
For example, the original read_pipe with 2 parameters is in the form

int read_pipe(pipe gentype p, gentype *e);

To get the indication for the pipe element type with in functions, we change it into this form

int read_pipe(pipe gentype p, char *e,int sizeofgentype);

This actually change the form of the OpenCL built-in functions, but can save a lot of things for the backend.
Another way is to get the pipe element type form the -cl-kernel-arg-info, the pipe is as the type qual and the element type for the type.
So which one do you think is better? Add a size or using kernel-arg-info, I am now wondering if the built-in for pipe is really needed. Hope you can give me some advice.

lib/CodeGen/CodeGenFunction.cpp

565

I will fix them, thank you.

lib/Sema/TreeTransform.h

5352

It seems to have no use, I will try to remove it and see if it can compile.

test/CodeGenOpenCL/pipe_types.cl

16

Good idea, I will remove some.

test/SemaOpenCL/pipes-1.2-negative.cl

2

Ok, I will add those checking for pipe access qualifier and element type.

[pxli168]

This comment was removed by pxli168.

[pxli168]

Fix some typo and remove unnecessary namespace, and add a new test case.
The Diff 43621 was on a wrong base, ignore it.

[pekka.jaaskelainen]

lib/CodeGen/CGOpenCLRuntime.cpp

108

I'm not sure if touching the built-in fingerprints for this is a good idea. It might lead to problems and confusion. Cannot one pass pipes as arguments to user functions too? Are the fingerprints of those functions then modified accordingly? It might become messy.

Because the packet size is known at host side, the pipes can be implemented as structs which holds the packet size as one of the member variables. The problem with this approach is how to exploit wider reads/writes instead of a scalar read/write loop + unpack/pack in case of vector datatypes.

If the size is known only at runtime, one cannot easily generate vector reads/writes even if the element is a vector datatype and it would be efficient to keep the packet in a vector register as long as possible. For helping this I'd add a metadata which can be utilized at compile time to make reading/writing from the pipe faster. But in a way that is already an optimization, not a requirement, to make pipes work.

The reading itself is platform dependent as the pipe can be even a hardware FIFO accessed using special instructions.

[pxli168]

lib/CodeGen/CGOpenCLRuntime.cpp

108

This is what I'm worry about, I don't think we need to give much information about an opaque type in OpenCL.

Actually we can get the element type from the metadata, and I think we can leave the optimization to the backend and let platform to choose which way to use for read/write pipe.

And I think the built-in function support for the pipe in OpenCL-C is not necessary in the clang, what do you think? Though it can do some check in Sema check, they can also be done in some llvm pass in backend. If the built-in is really needed, I will send another patch based on this included built-in support for pipe.

Thank you.

[pekka.jaaskelainen]

lib/CodeGen/CGOpenCLRuntime.cpp

108

As far as I've understood, no there's no need to add built-in function awareness to the frontend for this case. Sema checking/diagnostics is needed to ensure pipes are used only as function arguments, not local variables, for example. Is this patch missing it?

[pxli168]

lib/CodeGen/CGOpenCLRuntime.cpp

108

I think there are a lot of Sema checking about OpenCL2.0 are missing, the pipe could not be a local variable is just one, there are also some check are missing for reserve_id_t in my tests these days.
My plan is to use a patch to cover all these missing Sema check for OpenCL. That would be a hard work with the OpenCL Specification and would take a lot of time and may delay this patch, so could you accept this patch first and let me to finish the missing Sema check later to make sure cover more missing part.

[Anastasia]

lib/AST/ASTContext.cpp

3147

Could we update the comment here or otherwise I think it's best to be removed!

lib/CodeGen/CGOpenCLRuntime.cpp

108

I am Ok with not adding everything in one commit. We can revisit/modify things later on.

test/SemaOpenCL/invalid-pipes-cl2.0.cl

4

I can see more than one diagnostic being added in this patch, but the test covers only one.

[pxli168]

lib/AST/ASTContext.cpp

3147

OK, just removed the copy paste one

lib/CodeGen/CGOpenCLRuntime.cpp

108

Do you think we need the make the read/write_pipe as a builtin in clang? Since these function need the pipe element type to be the same with the pointer pointee type. I find it hard to handle this in a backend.

test/SemaOpenCL/invalid-pipes-cl2.0.cl

4

It seems the auto related diagnostic is not necessary, since auto can not be used in OpenCL.

And the "err_missing_actual_pipe_type" seems is used in a wrong place, it could not handle something like

pipe p

This will case "warning: type specifier missing, defaults to 'int'"

But something like

int pipe p

will has "error: missing actual type specifier for pipe"
It seems this should be call “cannot combine with previous 'int' declaration specifier”
And the "error: missing actual type specifier for pipe" should be placed somewhere else.

[pxli168]

Fix some unused diagnostic and wrong diagnostic. Add test for these diagnostics.

[Anastasia]

LGTM!

lib/CodeGen/CGOpenCLRuntime.cpp

108

Yes, I think we might, otherwise I don't see how we are going to allows any element type (including user defined types) for pipe without adding a template like functionality to C parsing.

[pxli168]

lib/CodeGen/CGOpenCLRuntime.cpp

108

OK, I will send a patch only for these two builtin function (I don't think other pipe functions need to be built-in), and I think we can discuss about the function mangle for them, now I have a version without mangle and a hard code version.

[Anastasia]

lib/CodeGen/CGOpenCLRuntime.cpp

108

I am afraid we might need to add all of the pipe functions as builtins in order to allow them to be called with any pipe element type including user defined types.

Otherwise, feel free to propose other ideas.

If you have a patch already, let's start the review and we will see how to move forward.

[uweigand]

Now that our build bot is up and running again, I noticed that the newly added test pipe_types.cl fails on SystemZ:

/home3/uweigand/llvm/llvm-head/tools/clang/test/CodeGenOpenCL/pipe_types.cl:26:11: error: expected string not found in input
// CHECK: define void @test5(%opencl.pipe_t* %p)                                                                            
          ^                                                                                                                 
<stdin>:34:40: note: scanning from here                                                                                     
define void @test4(%opencl.pipe_t* %p) #0 {                                                                                 
                                       ^                                                                                    
<stdin>:42:1: note: possible intended match here                                                                            
define void @test5(%opencl.pipe_t**) #0 {                                                                                   
^

For some reason, test5 gets an extra indirection in the input argument:

define void @test5(%opencl.pipe_t**) #0 {
entry:
  %p.addr = alloca %opencl.pipe_t*, align 16
  %p = load %opencl.pipe_t*, %opencl.pipe_t** %0, align 16
  store %opencl.pipe_t* %p, %opencl.pipe_t** %p.addr, align 16
  ret void
}

Are there supposed to be platform-specific differences in OpenCL types?

[Anastasia]

No, this shouldn't happen! There shouldn't be any difference in emitted IR depending on a platform. I also don't see any code in CodeGen that could specialize.

Is there a way to reproduce your compilation? Passing any triple?

[uweigand]

In D15603#338488, @Anastasia wrote:

No, this shouldn't happen! There shouldn't be any difference in emitted IR depending on a platform. I also don't see any code in CodeGen that could specialize.

Is there a way to reproduce your compilation? Passing any triple?

I see the problem when using:

clang --target=s390x-linux -S -O0 -emit-llvm -std=CL2.0 -o - pipe_types.cl

Using --target=i386-linux instead results in the expected output.

[Anastasia]

Yes, I see that it happens only for some vector types. The CodeGen follows quite different paths for both targets. And in the case of s390x-linux-gnu it ends up in ABIArgInfo::Indirect case of the second switch statement where an additional pointer will be added here:

ArgTypes[FirstIRArg] = LTy->getPointerTo();

I don't have enough knowledge at the moment of this ABI to tell whether it's Ok, but the generated code appears to be completely wrong.

As a temporary workaround to fix your build bot, I suggest you to add '-triple x86_64-linux-gnu' into RUN line of the test:

-// RUN: %clang_cc1 -emit-llvm -O0 -cl-std=CL2.0 -o - %s | FileCheck %s
+// RUN: %clang_cc1 -emit-llvm -O0 -cl-std=CL2.0 -o - -triple x86_64-linux-gnu %s | FileCheck %s

It has already been done before in OpenCL tests as we don't support most of targets anyways.

In the meantime, I will try to see if there could be a better fix for this.

[Anastasia]

Btw, just to be clear in my previous comment I was referring to the 2nd switch statement in CodeGenTypes::GetFunctionType that contains the line:

ArgTypes[FirstIRArg] = LTy->getPointerTo();

[uweigand]

In D15603#338593, @Anastasia wrote:

Yes, I see that it happens only for some vector types. The CodeGen follows quite different paths for both targets. And in the case of s390x-linux-gnu it ends up in ABIArgInfo::Indirect case of the second switch statement where an additional pointer will be added here:

ArgTypes[FirstIRArg] = LTy->getPointerTo();

I don't have enough knowledge at the moment of this ABI to tell whether it's Ok, but the generated code appears to be completely wrong.

Well, yes, on SystemZ we pass 16-byte vector types via implicit reference (using ABIArgInfo::Indirect) in the default case, i.e. when targeting an older CPU without SIMD. But the code generated for OpenCL pipes doesn't actually seem to correctly implement that convention either ... (It does work for normal calls via C/C++/...)

As a temporary workaround to fix your build bot, I suggest you to add '-triple x86_64-linux-gnu' into RUN line of the test:

-// RUN: %clang_cc1 -emit-llvm -O0 -cl-std=CL2.0 -o - %s | FileCheck %s
+// RUN: %clang_cc1 -emit-llvm -O0 -cl-std=CL2.0 -o - -triple x86_64-linux-gnu %s | FileCheck %s

It has already been done before in OpenCL tests as we don't support most of targets anyways.

OK, I've checked this in as rev. 259183. Thanks!

include/clang/AST/ASTContext.h

   mutable llvm::FoldingSet<AutoType> AutoTypes;
   mutable llvm::FoldingSet<AtomicType> AtomicTypes;
   llvm::FoldingSet<AttributedType> AttributedTypes;
+  mutable llvm::FoldingSet<PipeType> PipeTypes;
 
   mutable llvm::FoldingSet<QualifiedTemplateName> QualifiedTemplateNames;
   mutable llvm::FoldingSet<DependentTemplateName> DependentTemplateNames;

   /// blocks.
   QualType getBlockDescriptorType() const;
 
+  /// \brief Return pipe type for the specified type.
+  QualType getPipeType(QualType T) const;
+
   /// Gets the struct used to keep track of the extended descriptor for
   /// pointer to blocks.
   QualType getBlockDescriptorExtendedType() const;

include/clang/AST/RecursiveASTVisitor.h

 
 DEF_TRAVERSE_TYPE(AtomicType, { TRY_TO(TraverseType(T->getValueType())); })
 
+DEF_TRAVERSE_TYPE(PipeType, { TRY_TO(TraverseType(T->getElementType())); })
+
 #undef DEF_TRAVERSE_TYPE
 
 // ----------------- TypeLoc traversal -----------------

 
 DEF_TRAVERSE_TYPELOC(AtomicType, { TRY_TO(TraverseTypeLoc(TL.getValueLoc())); })
 
+DEF_TRAVERSE_TYPELOC(PipeType, { TRY_TO(TraverseTypeLoc(TL.getValueLoc())); })
+
 #undef DEF_TRAVERSE_TYPELOC
 
 // ----------------- Decl traversal -----------------

include/clang/AST/Type.h

   bool isNDRangeT() const;                      // OpenCL ndrange_t
   bool isReserveIDT() const;                    // OpenCL reserve_id_t
 
+  bool isPipeType() const;                      // OpenCL pipe type
   bool isOpenCLSpecificType() const;            // Any OpenCL specific type
 
   /// Determines if this type, which must satisfy

   }
 };
 
+/// PipeType - OpenCL20.
+class PipeType : public Type, public llvm::FoldingSetNode {
+  QualType ElementType;
+
+  PipeType(QualType elemType, QualType CanonicalPtr) :
+    Type(Pipe, CanonicalPtr, elemType->isDependentType(),
+         elemType->isInstantiationDependentType(),
+         elemType->isVariablyModifiedType(),
+         elemType->containsUnexpandedParameterPack()),
+    ElementType(elemType) {}
+  friend class ASTContext;  // ASTContext creates these.
+
+public:
+
+  QualType getElementType() const { return ElementType; }
+
+  bool isSugared() const { return false; }
+
+  QualType desugar() const { return QualType(this, 0); }
+
+  void Profile(llvm::FoldingSetNodeID &ID) {
+    Profile(ID, getElementType());
+  }
+
+  static void Profile(llvm::FoldingSetNodeID &ID, QualType T) {
+    ID.AddPointer(T.getAsOpaquePtr());
+  }
+
+
+  static bool classof(const Type *T) {
+    return T->getTypeClass() == Pipe;
+  }
+
+};
+
 /// A qualifier set is used to build a set of qualifiers.
 class QualifierCollector : public Qualifiers {
 public:

          isImage1dBufferT();
 }
 
+inline bool Type::isPipeType() const {
+  return isa<PipeType>(CanonicalType);
+}
+
 inline bool Type::isOpenCLSpecificType() const {
   return isSamplerT() || isEventT() || isImageType() || isClkEventT() ||
-         isQueueT() || isNDRangeT() || isReserveIDT();
+         isQueueT() || isNDRangeT() || isReserveIDT() || isPipeType();
 }
 
 inline bool Type::isTemplateTypeParmType() const {

include/clang/AST/TypeLoc.h

   }
 };
 
+struct PipeTypeLocInfo {
+  SourceLocation KWLoc;
+};
+
+class PipeTypeLoc : public ConcreteTypeLoc<UnqualTypeLoc, PipeTypeLoc, PipeType,
+                                           PipeTypeLocInfo> {
+public:
+  TypeLoc getValueLoc() const { return this->getInnerTypeLoc(); }
+
+  SourceRange getLocalSourceRange() const { return SourceRange(getKWLoc()); }
+
+  SourceLocation getKWLoc() const { return this->getLocalData()->KWLoc; }
+  void setKWLoc(SourceLocation Loc) { this->getLocalData()->KWLoc = Loc; }
 
+  void initializeLocal(ASTContext &Context, SourceLocation Loc) {
+    setKWLoc(Loc);
+  }
+
+  QualType getInnerType() const { return this->getTypePtr()->getElementType(); }
+};
 }
 
 #endif

include/clang/AST/TypeNodes.def

 TYPE(ObjCObject, Type)
 TYPE(ObjCInterface, ObjCObjectType)
 TYPE(ObjCObjectPointer, Type)
+TYPE(Pipe, Type)
 TYPE(Atomic, Type)
 
 #ifdef LAST_TYPE

include/clang/Basic/DiagnosticSemaKinds.td

   "sampler type cannot be used with the __local and __global address space qualifiers">;
 def err_opencl_global_invalid_addr_space : Error<
   "program scope variable must reside in %0 address space">;
+def err_missing_actual_pipe_type : Error<
+  "missing actual type specifier for pipe">;
+def err_reference_pipe_type : Error <
+  "pipes packet types cannot be of reference type">;
 def err_opencl_no_main : Error<"%select{function|kernel}0 cannot be called 'main'">;
 def err_opencl_kernel_attr :
   Error<"attribute %0 can only be applied to a kernel function">;

include/clang/Basic/Specifiers.h

     TSS_unsigned
   };
   
+  enum TypeSpecifiersPipe {
+    TSP_unspecified,
+    TSP_pipe
+  };
+
   /// \brief Specifies the kind of type.
   enum TypeSpecifierType {
     TST_unspecified,

include/clang/Basic/TokenKinds.def

 // OpenMP Type Traits
 KEYWORD(__builtin_omp_required_simd_align, KEYALL)
 
+KEYWORD(pipe                        , KEYOPENCL)
+
 // Borland Extensions.
 KEYWORD(__pascal                    , KEYALL)
 

include/clang/Sema/DeclSpec.h

   unsigned TypeAltiVecPixel : 1;
   unsigned TypeAltiVecBool : 1;
   unsigned TypeSpecOwned : 1;
+  unsigned TypeSpecPipe : 1;
 
   // type-qualifiers
   unsigned TypeQualifiers : 4;  // Bitwise OR of TQ.

   SourceLocation FS_inlineLoc, FS_virtualLoc, FS_explicitLoc, FS_noreturnLoc;
   SourceLocation FS_forceinlineLoc;
   SourceLocation FriendLoc, ModulePrivateLoc, ConstexprLoc, ConceptLoc;
+  SourceLocation TQ_pipeLoc;
 
   WrittenBuiltinSpecs writtenBS;
   void SaveWrittenBuiltinSpecs();

       TypeAltiVecPixel(false),
       TypeAltiVecBool(false),
       TypeSpecOwned(false),
+      TypeSpecPipe(false),
       TypeQualifiers(TQ_unspecified),
       FS_inline_specified(false),
       FS_forceinline_specified(false),

   bool isTypeAltiVecBool() const { return TypeAltiVecBool; }
   bool isTypeSpecOwned() const { return TypeSpecOwned; }
   bool isTypeRep() const { return isTypeRep((TST) TypeSpecType); }
+  bool isTypeSpecPipe() const { return TypeSpecPipe; }
 
   ParsedType getRepAsType() const {
     assert(isTypeRep((TST) TypeSpecType) && "DeclSpec does not store a type");

   SourceLocation getRestrictSpecLoc() const { return TQ_restrictLoc; }
   SourceLocation getVolatileSpecLoc() const { return TQ_volatileLoc; }
   SourceLocation getAtomicSpecLoc() const { return TQ_atomicLoc; }
+  SourceLocation getPipeLoc() const { return TQ_pipeLoc; }
 
   /// \brief Clear out all of the type qualifiers.
   void ClearTypeQualifiers() {

     TQ_restrictLoc = SourceLocation();
     TQ_volatileLoc = SourceLocation();
     TQ_atomicLoc = SourceLocation();
+    TQ_pipeLoc = SourceLocation();
   }
 
   // function-specifier

   bool SetTypeAltiVecBool(bool isAltiVecBool, SourceLocation Loc,
                        const char *&PrevSpec, unsigned &DiagID,
                        const PrintingPolicy &Policy);
+  bool SetTypePipe(bool isPipe, SourceLocation Loc,
+                       const char *&PrevSpec, unsigned &DiagID,
+                       const PrintingPolicy &Policy);
   bool SetTypeSpecError();
   void UpdateDeclRep(Decl *Rep) {
     assert(isDeclRep((TST) TypeSpecType));

 /// This is intended to be a small value object.
 struct DeclaratorChunk {
   enum {
-    Pointer, Reference, Array, Function, BlockPointer, MemberPointer, Paren
+    Pointer, Reference, Array, Function, BlockPointer, MemberPointer, Paren, Pipe
   } Kind;
 
   /// Loc - The place where this type was defined.

     }
   };
 
+  struct PipeTypeInfo : TypeInfoCommon {
+  /// The access writes.
+  unsigned AccessWrites : 3;
+
+  void destroy() {}
+  };
+
   union {
     TypeInfoCommon        Common;
     PointerTypeInfo       Ptr;

     FunctionTypeInfo      Fun;
     BlockPointerTypeInfo  Cls;
     MemberPointerTypeInfo Mem;
+    PipeTypeInfo          PipeInfo;
   };
 
   void destroy() {

     case DeclaratorChunk::Array:         return Arr.destroy();
     case DeclaratorChunk::MemberPointer: return Mem.destroy();
     case DeclaratorChunk::Paren:         return;
+    case DeclaratorChunk::Pipe:          return PipeInfo.destroy();
     }
   }
 

     return I;
   }
 
+  /// \brief Return a DeclaratorChunk for a block.
+  static DeclaratorChunk getPipe(unsigned TypeQuals,
+                                 SourceLocation Loc) {
+    DeclaratorChunk I;
+    I.Kind          = Pipe;
+    I.Loc           = Loc;
+    I.Cls.TypeQuals = TypeQuals;
+    I.Cls.AttrList  = 0;
+    return I;
+  }
+
   static DeclaratorChunk getMemberPointer(const CXXScopeSpec &SS,
                                           unsigned TypeQuals,
                                           SourceLocation Loc) {

       case DeclaratorChunk::Array:
       case DeclaratorChunk::BlockPointer:
       case DeclaratorChunk::MemberPointer:
+      case DeclaratorChunk::Pipe:
         return false;
       }
       llvm_unreachable("Invalid type chunk");

include/clang/Sema/Sema.h

                                  SourceLocation Loc, DeclarationName Entity);
   QualType BuildParenType(QualType T);
   QualType BuildAtomicType(QualType T, SourceLocation Loc);
+  QualType BuildPipeType(QualType T,
+                         SourceLocation Loc);
 
   TypeSourceInfo *GetTypeForDeclarator(Declarator &D, Scope *S);
   TypeSourceInfo *GetTypeForDeclaratorCast(Declarator &D, QualType FromTy);

include/clang/Serialization/ASTBitCodes.h

       /// \brief A DecayedType record.
       TYPE_DECAYED               = 41,
       /// \brief An AdjustedType record.
-      TYPE_ADJUSTED              = 42
+      TYPE_ADJUSTED              = 42,
+      /// \brief A PipeType record.
+      TYPE_PIPE                  = 43
     };
 
     /// \brief The type IDs for special types constructed by semantic

lib/AST/ASTContext.cpp

       Align = static_cast<unsigned>(Width);
     }
   }
+  break;
+
+  case Type::Pipe: {
+    TypeInfo Info = getTypeInfo(cast<PipeType>(T)->getElementType());
+    Width = Info.Width;
+    Align = Info.Align;
+  }
 
   }
 

   case Type::FunctionProto:
   case Type::BlockPointer:
   case Type::MemberPointer:
+  case Type::Pipe:
     return type;
 
   // These types can be variably-modified.  All these modifications

   return QualType(FTP, 0);
 }
 
+/// Return pipe type for the specified type.
+QualType ASTContext::getPipeType(QualType T) const {
+  llvm::FoldingSetNodeID ID;
+  PipeType::Profile(ID, T);
+
+  void *InsertPos = 0;
+  if (PipeType *PT = PipeTypes.FindNodeOrInsertPos(ID, InsertPos))
+    return QualType(PT, 0);
+
+  // If the pipe element type isn't canonical, this won't be a canonical type
+  // either, so fill in the canonical type field.
+  QualType Canonical;
+  if (!T.isCanonical()) {
+    Canonical = getPipeType(getCanonicalType(T));
+
+    // Get the new insert position for the node we care about.
+    PipeType *NewIP = PipeTypes.FindNodeOrInsertPos(ID, InsertPos);
+    assert(!NewIP && "Shouldn't be in the map!");
+    (void)NewIP;
+  }
+  PipeType *New = new (*this, TypeAlignment) PipeType(T, Canonical);
+  Types.push_back(New);
+  PipeTypes.InsertNode(New, InsertPos);
+  return QualType(New, 0);
+}
+
 #ifndef NDEBUG
 static bool NeedsInjectedClassNameType(const RecordDecl *D) {
   if (!isa<CXXRecordDecl>(D)) return false;

   case Type::Auto:
     return;
 
+  case Type::Pipe:
 #define ABSTRACT_TYPE(KIND, BASE)
 #define TYPE(KIND, BASE)
 #define DEPENDENT_TYPE(KIND, BASE) \

 
     return QualType();
   }
+  case Type::Pipe:
+  {
+    // Merge two pointer types, while trying to preserve typedef info
+    QualType LHSValue = LHS->getAs<PipeType>()->getElementType();
+    QualType RHSValue = RHS->getAs<PipeType>()->getElementType();
+    if (Unqualified) {
+      LHSValue = LHSValue.getUnqualifiedType();
+      RHSValue = RHSValue.getUnqualifiedType();
+    }
+    QualType ResultType = mergeTypes(LHSValue, RHSValue, false,
+                                     Unqualified);
+    if (ResultType.isNull()) return QualType();
+    if (getCanonicalType(LHSValue) == getCanonicalType(ResultType))
+      return LHS;
+    if (getCanonicalType(RHSValue) == getCanonicalType(ResultType))
+      return RHS;
+    return getPipeType(ResultType);
+  }
   }
 
   llvm_unreachable("Invalid Type::Class!");

lib/AST/ASTImporter.cpp

     break;
   }
 
+  case Type::Pipe: {
+    if (!IsStructurallyEquivalent(Context,
+                                  cast<PipeType>(T1)->getElementType(),
+                                  cast<PipeType>(T2)->getElementType()))
+      return false;
+    break;
+  }
+
   } // end switch
 
   return true;

lib/AST/ItaniumMangle.cpp

   case Type::ObjCInterface:
   case Type::ObjCObjectPointer:
   case Type::Atomic:
+  case Type::Pipe:
     llvm_unreachable("type is illegal as a nested name specifier");
 
   case Type::SubstTemplateTypeParmPack:

   mangleType(T->getValueType());
 }
 
+void CXXNameMangler::mangleType(const PipeType *T) {
+  // Pipe type mangling rules are described in SPIR 2.0 specification
+  // A.1 Data types and A.3 Summary of changes
+  // <type> ::= 8ocl_pipe
+  Out << "8ocl_pipe";
+}
+
 void CXXNameMangler::mangleIntegerLiteral(QualType T,
                                           const llvm::APSInt &Value) {
   //  <expr-primary> ::= L <type> <value number> E # integer literal

lib/AST/MicrosoftMangle.cpp

     << Range;
 }
 
+void MicrosoftCXXNameMangler::mangleType(const PipeType *T, Qualifiers,
+                                         SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this OpenCL pipe type yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
 void MicrosoftMangleContextImpl::mangleCXXName(const NamedDecl *D,
                                                raw_ostream &Out) {
   assert((isa<FunctionDecl>(D) || isa<VarDecl>(D)) &&

lib/AST/Type.cpp

     return Cache::get(cast<ObjCObjectPointerType>(T)->getPointeeType());
   case Type::Atomic:
     return Cache::get(cast<AtomicType>(T)->getValueType());
+  case Type::Pipe:
+    return Cache::get(cast<PipeType>(T)->getElementType());
   }
 
   llvm_unreachable("unhandled type class");

     return computeLinkageInfo(cast<ObjCObjectPointerType>(T)->getPointeeType());
   case Type::Atomic:
     return computeLinkageInfo(cast<AtomicType>(T)->getValueType());
+  case Type::Pipe:
+    return computeLinkageInfo(cast<PipeType>(T)->getElementType());
   }
 
   llvm_unreachable("unhandled type class");

   case Type::ObjCObject:
   case Type::ObjCInterface:
   case Type::Atomic:
+  case Type::Pipe:
     return false;
   }
   llvm_unreachable("bad type kind!");

lib/AST/TypePrinter.cpp

     case Type::ObjCObject:
     case Type::ObjCInterface:
     case Type::Atomic:
+    case Type::Pipe:
       CanPrefixQualifiers = true;
       break;
       

 }
 void TypePrinter::printAtomicAfter(const AtomicType *T, raw_ostream &OS) { }
 
+void TypePrinter::printPipeBefore(const PipeType *T, raw_ostream &OS) {
+  IncludeStrongLifetimeRAII Strong(Policy);
+
+  OS << "pipe";
+  spaceBeforePlaceHolder(OS);
+}
+
+void TypePrinter::printPipeAfter(const PipeType *T, raw_ostream &OS) {
+}
 /// Appends the given scope to the end of a string.
 void TypePrinter::AppendScope(DeclContext *DC, raw_ostream &OS) {
   if (DC->isTranslationUnit()) return;

lib/CodeGen/CGDebugInfo.h

   llvm::DIType *CreateType(const RValueReferenceType *Ty, llvm::DIFile *Unit);
   llvm::DIType *CreateType(const MemberPointerType *Ty, llvm::DIFile *F);
   llvm::DIType *CreateType(const AtomicType *Ty, llvm::DIFile *F);
+  llvm::DIType *CreateType(const PipeType *Ty, llvm::DIFile *F);
   /// Get enumeration type.
   llvm::DIType *CreateEnumType(const EnumType *Ty);
   llvm::DIType *CreateTypeDefinition(const EnumType *Ty);

lib/CodeGen/CGDebugInfo.cpp

   return getOrCreateType(Ty->getValueType(), U);
 }
 
+llvm::DIType* CGDebugInfo::CreateType(const PipeType *Ty,
+                                     llvm::DIFile *U) {
+  return getOrCreateType(Ty->getElementType(), U);
+}
+
 llvm::DIType *CGDebugInfo::CreateEnumType(const EnumType *Ty) {
   const EnumDecl *ED = Ty->getDecl();
 

   case Type::Atomic:
     return CreateType(cast<AtomicType>(Ty), Unit);
 
+  case Type::Pipe:
+    return CreateType(cast<PipeType>(Ty), Unit);
+
   case Type::TemplateSpecialization:
     return CreateType(cast<TemplateSpecializationType>(Ty), Unit);
 

lib/CodeGen/CGOpenCLRuntime.h

 class CGOpenCLRuntime {
 protected:
   CodeGenModule &CGM;
+  llvm::Type *PipeTy;
 
 public:
-  CGOpenCLRuntime(CodeGenModule &CGM) : CGM(CGM) {}
+  CGOpenCLRuntime(CodeGenModule &CGM) : CGM(CGM), PipeTy(nullptr) {}
   virtual ~CGOpenCLRuntime();
 
   /// Emit the IR required for a work-group-local variable declaration, and add

                                          const VarDecl &D);
 
   virtual llvm::Type *convertOpenCLSpecificType(const Type *T);
+
+  virtual llvm::Type *getPipeType();
 };
 
 }

lib/CodeGen/CGOpenCLRuntime.cpp

         llvm::StructType::create(Ctx, "opencl.reserve_id_t"), 0);
   }
 }
+
+llvm::Type *CGOpenCLRuntime::getPipeType() {
+  if (!PipeTy){
+    uint32_t PipeAddrSpc =
+      CGM.getContext().getTargetAddressSpace(LangAS::opencl_global);
+    PipeTy = llvm::PointerType::get(llvm::StructType::create(
+      CGM.getLLVMContext(), "opencl.pipe_t"), PipeAddrSpc);
+  }
+
+  return PipeTy;
+}

lib/CodeGen/CodeGenFunction.cpp

     case Type::FunctionNoProto:
     case Type::Enum:
     case Type::ObjCObjectPointer:
+    case Type::Pipe:
       return TEK_Scalar;
 
     // Complexes.

         typeQuals += typeQuals.empty() ? "volatile" : " volatile";
     } else {
       uint32_t AddrSpc = 0;
-      if (ty->isImageType())
+      bool isPipe = ty->isPipeType();
+      if (ty->isImageType() || isPipe)
         AddrSpc =
           CGM.getContext().getTargetAddressSpace(LangAS::opencl_global);
 

           llvm::ConstantAsMetadata::get(Builder.getInt32(AddrSpc)));
 
       // Get argument type name.
-      std::string typeName = ty.getUnqualifiedType().getAsString(Policy);
+      std::string typeName;
+      if (isPipe)
+        typeName = cast<PipeType>(ty)->getElementType().getAsString(Policy);
+      else
+        typeName = ty.getUnqualifiedType().getAsString(Policy);
 
       // Turn "unsigned type" to "utype"
       std::string::size_type pos = typeName.find("unsigned");

 
       argTypeNames.push_back(llvm::MDString::get(Context, typeName));
 
-      std::string baseTypeName =
+      std::string baseTypeName;
+      if (isPipe)
+        baseTypeName =
+          cast<PipeType>(ty)->getElementType().getCanonicalType().getAsString(Policy);
+      else
+        baseTypeName =
           ty.getUnqualifiedType().getCanonicalType().getAsString(Policy);
 
       // Turn "unsigned type" to "utype"

         typeQuals = "const";
       if (ty.isVolatileQualified())
         typeQuals += typeQuals.empty() ? "volatile" : " volatile";
+      if (isPipe)
+        typeQuals = "pipe";
     }
 
     argTypeQuals.push_back(llvm::MDString::get(Context, typeQuals));
 
-    // Get image access qualifier:
-    if (ty->isImageType()) {
+    // Get image and pipe access qualifier:
+    // FIXME: now image and pipe share the same access qualifier maybe we can
+    // refine it to OpenCL access qualifier and also handle write_read
+    if (ty->isImageType()|| ty->isPipeType()) {
       const OpenCLImageAccessAttr *A = parm->getAttr<OpenCLImageAccessAttr>();
       if (A && A->isWriteOnly())
         accessQuals.push_back(llvm::MDString::get(Context, "write_only"));

     case Type::Atomic:
       type = cast<AtomicType>(ty)->getValueType();
       break;
+
+    case Type::Pipe:
+      type = cast<PipeType>(ty)->getElementType();
+      break;
     }
   } while (type->isVariablyModifiedType());
 }

lib/CodeGen/CodeGenTypes.cpp

     }
     break;
   }
+  case Type::Pipe: {
+    ResultType = CGM.getOpenCLRuntime().getPipeType();
+    break;
+  }
   }
   
   assert(ResultType && "Didn't convert a type?");

lib/CodeGen/ItaniumCXXABI.cpp

   case Type::Auto:
     llvm_unreachable("Undeduced auto type shouldn't get here");
 
+  case Type::Pipe:
+    llvm_unreachable("Pipe types shouldn't get here");
+
   case Type::Builtin:
   // GCC treats vector and complex types as fundamental types.
   case Type::Vector:

   case Type::Auto:
     llvm_unreachable("Undeduced auto type shouldn't get here");
 
+  case Type::Pipe:
+    llvm_unreachable("Pipe type shouldn't get here");
+
   case Type::ConstantArray:
   case Type::IncompleteArray:
   case Type::VariableArray:

lib/Parse/ParseDecl.cpp

     case tok::kw___bool:
       isInvalid = DS.SetTypeAltiVecBool(true, Loc, PrevSpec, DiagID, Policy);
       break;
+    case tok::kw_pipe:
+      if (!getLangOpts().OpenCL || (getLangOpts().OpenCLVersion < 200)) {
+        // OpenCL 2.0 defined this keyword. OpenCL 1.2 and earlier should
+        // support the "pipe" word as identifier.
+        Tok.getIdentifierInfo()->revertTokenIDToIdentifier();
+        goto DoneWithDeclSpec;
+      }
+      isInvalid = DS.SetTypePipe(true, Loc, PrevSpec, DiagID, Policy);
+      break;
     case tok::kw___unknown_anytype:
       isInvalid = DS.SetTypeSpecType(TST_unknown_anytype, Loc,
                                      PrevSpec, DiagID, Policy);

   switch (Tok.getKind()) {
   default: return false;
 
+  case tok::kw_pipe:
+    return getLangOpts().OpenCL && (getLangOpts().OpenCLVersion >= 200);
+
   case tok::identifier:   // foo::bar
     // Unfortunate hack to support "Class.factoryMethod" notation.
     if (getLangOpts().ObjC1 && NextToken().is(tok::period))

   if (Kind == tok::star || Kind == tok::caret)
     return true;
 
+  if ((Kind == tok::kw_pipe) && Lang.OpenCL && (Lang.OpenCLVersion >= 200))
+    return true;
+
   if (!Lang.CPlusPlus)
     return false;
 

   return false;
 }
 
+// Indicates whether the given declarator is a pipe declarator.
+static bool isPipeDeclerator(const Declarator &D) {
+  const unsigned NumTypes = D.getNumTypeObjects();
+
+  for (unsigned Idx = 0; Idx != NumTypes; ++Idx)
+    if (DeclaratorChunk::Pipe == D.getTypeObject(Idx).Kind)
+      return true;
+
+  return false;
+}
+
 /// ParseDeclaratorInternal - Parse a C or C++ declarator. The direct-declarator
 /// is parsed by the function passed to it. Pass null, and the direct-declarator
 /// isn't parsed at all, making this function effectively parse the C++

   }
 
   tok::TokenKind Kind = Tok.getKind();
+
+  if (D.getDeclSpec().isTypeSpecPipe() && !isPipeDeclerator(D)) {
+    DeclSpec &DS = D.getMutableDeclSpec();
+
+    D.AddTypeInfo(
+        DeclaratorChunk::getPipe(DS.getTypeQualifiers(), DS.getPipeLoc()),
+        DS.getAttributes(), SourceLocation());
+  }
+
   // Not a pointer, C++ reference, or block.
   if (!isPtrOperatorToken(Kind, getLangOpts(), D.getContext())) {
     if (DirectDeclParser)

     case DeclaratorChunk::Reference:
     case DeclaratorChunk::BlockPointer:
     case DeclaratorChunk::MemberPointer:
+    case DeclaratorChunk::Pipe:
       NeedParens = true;
       break;
     case DeclaratorChunk::Array:

lib/Sema/DeclSpec.cpp

     case DeclaratorChunk::Array:
     case DeclaratorChunk::BlockPointer:
     case DeclaratorChunk::MemberPointer:
+    case DeclaratorChunk::Pipe:
       return false;
     }
     llvm_unreachable("Invalid type chunk");

   return false;
 }
 
+bool DeclSpec::SetTypePipe(bool isPipe, SourceLocation Loc,
+                           const char *&PrevSpec, unsigned &DiagID,
+                           const PrintingPolicy &Policy) {
+
+  if (TypeSpecType != TST_unspecified) {
+    PrevSpec = DeclSpec::getSpecifierName((TST)TypeSpecType, Policy);
+    DiagID = diag::err_invalid_decl_spec_combination;
+    return true;
+  }
+
+  if (isPipe) {
+    TypeSpecPipe = TSP_pipe;
+  }
+  return false;
+}
+
 bool DeclSpec::SetTypeAltiVecPixel(bool isAltiVecPixel, SourceLocation Loc,
                           const char *&PrevSpec, unsigned &DiagID,
                           const PrintingPolicy &Policy) {

lib/Sema/SemaDecl.cpp

     for (auto Param : NewFD->params())
       checkIsValidOpenCLKernelParameter(*this, D, Param, ValidTypes);
   }
+  for (FunctionDecl::param_iterator PI = NewFD->param_begin(),
+       PE = NewFD->param_end(); PI != PE; ++PI) {
+    ParmVarDecl *Param = *PI;
+    QualType PT = Param->getType();
+
+    // OpenCL 2.0 pipe restrictions forbids pipe packet types to be non-value
+    // types.
+    if (getLangOpts().OpenCLVersion >= 200) {
+      if(const PipeType *PipeTy = PT->getAs<PipeType>()) {
+        QualType ElemTy = PipeTy->getElementType();
+          if (ElemTy->isReferenceType() || ElemTy->isPointerType()) {
+            Diag(Param->getTypeSpecStartLoc(), diag::err_reference_pipe_type );
+            D.setInvalidType();
+          }
+      }
+    }
+  }
 
   MarkUnusedFileScopedDecl(NewFD);
 

lib/Sema/SemaDeclCXX.cpp

       case DeclaratorChunk::BlockPointer:
       case DeclaratorChunk::Reference:
       case DeclaratorChunk::MemberPointer:
+      case DeclaratorChunk::Pipe:
         extendLeft(Before, Chunk.getSourceRange());
         break;
 

lib/Sema/SemaExpr.cpp

         case Type::ObjCObject:
         case Type::ObjCInterface:
         case Type::ObjCObjectPointer:
+        case Type::Pipe:
           llvm_unreachable("type class is never variably-modified!");
         case Type::Adjusted:
           QTy = cast<AdjustedType>(Ty)->getOriginalType();

lib/Sema/SemaLookup.cpp

     case Type::Atomic:
       T = cast<AtomicType>(T)->getValueType().getTypePtr();
       continue;
+    case Type::Pipe:
+      T = cast<PipeType>(T)->getElementType().getTypePtr();
+      continue;
     }
 
     if (Queue.empty())

lib/Sema/SemaTemplate.cpp

   return Visit(T->getValueType());
 }
 
+bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
+  return false;
+}
+
 bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
   if (Tag->getDeclContext()->isFunctionOrMethod()) {
     S.Diag(SR.getBegin(),

lib/Sema/SemaTemplateDeduction.cpp

     case Type::Auto:
     case Type::DependentTemplateSpecialization:
     case Type::PackExpansion:
+    case Type::Pipe:
       // No template argument deduction for these types
       return Sema::TDK_Success;
   }

   case Type::ObjCObject:
   case Type::ObjCObjectPointer:
   case Type::UnresolvedUsing:
+  case Type::Pipe:
 #define TYPE(Class, Base)
 #define ABSTRACT_TYPE(Class, Base)
 #define DEPENDENT_TYPE(Class, Base)

lib/Sema/SemaTemplateVariadic.cpp

     case DeclaratorChunk::Pointer:
     case DeclaratorChunk::Reference:
     case DeclaratorChunk::Paren:
+    case DeclaratorChunk::Pipe:
     case DeclaratorChunk::BlockPointer:
       // These declarator chunks cannot contain any parameter packs.
       break;

lib/Sema/SemaType.cpp

     case DeclaratorChunk::Array:
     case DeclaratorChunk::Reference:
     case DeclaratorChunk::MemberPointer:
+    case DeclaratorChunk::Pipe:
       return result;
 
     // If we do find a function declarator, scan inwards from that,

         case DeclaratorChunk::Array:
         case DeclaratorChunk::Function:
         case DeclaratorChunk::Reference:
+        case DeclaratorChunk::Pipe:
           continue;
 
         case DeclaratorChunk::MemberPointer:

     // Don't walk through these.
     case DeclaratorChunk::Reference:
     case DeclaratorChunk::MemberPointer:
+    case DeclaratorChunk::Pipe:
       goto error;
     }
   }

     case DeclaratorChunk::MemberPointer:
     case DeclaratorChunk::Paren:
     case DeclaratorChunk::Array:
+    case DeclaratorChunk::Pipe:
       continue;
 
     case DeclaratorChunk::Function:

     case DeclaratorChunk::Array:
     case DeclaratorChunk::Reference:
     case DeclaratorChunk::MemberPointer:
+    case DeclaratorChunk::Pipe:
       continue;
     }
   }

         // value being declared, poison it as invalid so we don't get chains of
         // errors.
         declarator.setInvalidType(true);
+      } else if (S.getLangOpts().OpenCLVersion >= 200 && DS.isTypeSpecPipe()){
+        S.Diag(DeclLoc, diag::err_missing_actual_pipe_type)
+          << DS.getSourceRange();
+        declarator.setInvalidType(true);
       } else {
         S.Diag(DeclLoc, diag::ext_missing_type_specifier)
           << DS.getSourceRange();

   // Apply any type attributes from the decl spec.  This may cause the
   // list of type attributes to be temporarily saved while the type
   // attributes are pushed around.
-  processTypeAttrs(state, Result, TAL_DeclSpec, DS.getAttributes().getList());
+  // pipe attributes will be handled later ( at GetFullTypeForDeclarator )
+  if (!DS.isTypeSpecPipe())
+      processTypeAttrs(state, Result, TAL_DeclSpec, DS.getAttributes().getList());
 
   // Apply const/volatile/restrict qualifiers to T.
   if (unsigned TypeQuals = DS.getTypeQualifiers()) {

   return Context.getRValueReferenceType(T);
 }
 
+/// \brief Build a Pipe type.
+///
+/// \param T The type to which we'll be building a Pipe.
+///
+/// \param Loc We do not use it for now.
+///
+/// \returns A suitable pipe type, if there are no errors. Otherwise, returns a
+/// NULL type.
+QualType Sema::BuildPipeType(QualType T, SourceLocation Loc) {
+  assert(!T->isObjCObjectType() && "Should build ObjCObjectPointerType");
+
+  // Build the pipe type.
+  return Context.getPipeType(T);
+}
+
 /// Check whether the specified array size makes the array type a VLA.  If so,
 /// return true, if not, return the size of the array in SizeVal.
 static bool isArraySizeVLA(Sema &S, Expr *ArraySize, llvm::APSInt &SizeVal) {

     case DeclaratorChunk::Array: // suppress if written (id[])?
     case DeclaratorChunk::Function:
     case DeclaratorChunk::MemberPointer:
+    case DeclaratorChunk::Pipe:
       return;
     }
   }

     case DeclaratorChunk::Reference:
     case DeclaratorChunk::Array:
     case DeclaratorChunk::MemberPointer:
+    case DeclaratorChunk::Pipe:
       // FIXME: We can't currently provide an accurate source location and a
       // fix-it hint for these.
       unsigned AtomicQual = RetTy->isAtomicType() ? DeclSpec::TQ_atomic : 0;

     switch (chunk.Kind) {
     case DeclaratorChunk::Array:
     case DeclaratorChunk::Function:
+    case DeclaratorChunk::Pipe:
       break;
 
     case DeclaratorChunk::BlockPointer:

         case DeclaratorChunk::Array:
           DiagKind = 2;
           break;
+        case DeclaratorChunk::Pipe:
+          break;
         }
 
         S.Diag(DeclChunk.Loc, DiagId) << DiagKind;

       switch (chunk.Kind) {
       case DeclaratorChunk::Array:
       case DeclaratorChunk::Function:
+      case DeclaratorChunk::Pipe:
         break;
 
       case DeclaratorChunk::BlockPointer:

             break;
           case DeclaratorChunk::Function:
           case DeclaratorChunk::BlockPointer:
+          case DeclaratorChunk::Pipe:
             // These are invalid anyway, so just ignore.
             break;
           }

 
       break;
     }
-    case DeclaratorChunk::MemberPointer:
+    case DeclaratorChunk::MemberPointer: {
       // The scope spec must refer to a class, or be dependent.
       CXXScopeSpec &SS = DeclType.Mem.Scope();
       QualType ClsType;

       break;
     }
 
+    case DeclaratorChunk::Pipe: {
+      T = S.BuildPipeType(T, DeclType.Loc );
+      break;
+    }
+    }
+
     if (T.isNull()) {
       D.setInvalidType(true);
       T = Context.IntTy;

 
     case DeclaratorChunk::Function:
     case DeclaratorChunk::MemberPointer:
+    case DeclaratorChunk::Pipe:
       return;
     }
   }

       }
     }
 
+    void VisitPipeTypeLoc(PipeTypeLoc TL) {
+      TL.setKWLoc(DS.getTypeSpecTypeLoc());
+
+      TypeSourceInfo *TInfo = 0;
+      Sema::GetTypeFromParser(DS.getRepAsType(), &TInfo);
+      TL.getValueLoc().initializeFullCopy(TInfo->getTypeLoc());
+    }
+
     void VisitTypeLoc(TypeLoc TL) {
       // FIXME: add other typespec types and change this to an assert.
       TL.initialize(Context, DS.getTypeSpecTypeLoc());

       TL.setLParenLoc(Chunk.Loc);
       TL.setRParenLoc(Chunk.EndLoc);
     }
+    void VisitPipeTypeLoc(PipeTypeLoc TL) {
+      assert(Chunk.Kind == DeclaratorChunk::Pipe);
+      TL.setKWLoc(Chunk.Loc);
+    }
 
     void VisitTypeLoc(TypeLoc TL) {
       llvm_unreachable("unsupported TypeLoc kind in declarator!");

   case DeclaratorChunk::Function:
   case DeclaratorChunk::Array:
   case DeclaratorChunk::Paren:
+  case DeclaratorChunk::Pipe:
     llvm_unreachable("cannot be _Atomic qualified");
 
   case DeclaratorChunk::Pointer:

       
     // Don't walk through these.
     case DeclaratorChunk::Reference:
+    case DeclaratorChunk::Pipe:
       return false;
     }
   }

lib/Sema/TreeTransform.h

   /// Subclasses may override this routine to provide different behavior.
   QualType RebuildAtomicType(QualType ValueType, SourceLocation KWLoc);
 
+  /// \brief Build a new pipe type given its value type.
+  QualType RebuildPipeType(QualType ValueType, SourceLocation KWLoc);
+
   /// \brief Build a new template name given a nested name specifier, a flag
   /// indicating whether the "template" keyword was provided, and the template
   /// that the template name refers to.

   return Result;
 }
 
+template <typename Derived>
+QualType TreeTransform<Derived>::TransformPipeType(TypeLocBuilder &TLB,
+                                                   PipeTypeLoc TL) {
+  QualType ValueType = getDerived().TransformType(TLB, TL.getValueLoc());
+  if (ValueType.isNull())
+    return QualType();
+
+  QualType Result = TL.getType();
+  if (getDerived().AlwaysRebuild() || ValueType != TL.getValueLoc().getType()) {
+    Result = getDerived().RebuildPipeType(ValueType, TL.getKWLoc());
+    if (Result.isNull())
+      return QualType();
+  }
+
+  PipeTypeLoc NewTL = TLB.push<PipeTypeLoc>(Result);
+  NewTL.setKWLoc(TL.getKWLoc());
+
+  return Result;
+}
+
   /// \brief Simple iterator that traverses the template arguments in a
   /// container that provides a \c getArgLoc() member function.
   ///

 }
 
 template<typename Derived>
+QualType TreeTransform<Derived>::RebuildPipeType(QualType ValueType,
+                                                   SourceLocation KWLoc) {
+  return SemaRef.BuildPipeType(ValueType, KWLoc);
+}
+
+template<typename Derived>
 TemplateName
 TreeTransform<Derived>::RebuildTemplateName(CXXScopeSpec &SS,
                                             bool TemplateKW,

lib/Serialization/ASTReader.cpp

     QualType ValueType = readType(*Loc.F, Record, Idx);
     return Context.getAtomicType(ValueType);
   }
+
+  case TYPE_PIPE: {
+    if (Record.size() != 1) {
+      Error("Incorrect encoding of pipe type");
+      return QualType();
+    }
+
+    // Reading the pipe element type.
+    QualType ElementType = readType(*Loc.F, Record, Idx);
+    return Context.getPipeType(ElementType);
+  }
   }
   llvm_unreachable("Invalid TypeCode!");
 }

   TL.setLParenLoc(ReadSourceLocation(Record, Idx));
   TL.setRParenLoc(ReadSourceLocation(Record, Idx));
 }
+void TypeLocReader::VisitPipeTypeLoc(PipeTypeLoc TL) {
+  TL.setKWLoc(ReadSourceLocation(Record, Idx));
+}
 
 TypeSourceInfo *ASTReader::GetTypeSourceInfo(ModuleFile &F,
                                              const RecordData &Record,

lib/Serialization/ASTWriter.cpp

   Code = TYPE_ATOMIC;
 }
 
+void
+ASTTypeWriter::VisitPipeType(const PipeType *T) {
+  Writer.AddTypeRef(T->getElementType(), Record);
+  Code = TYPE_PIPE;
+}
+
 namespace {
 
 class TypeLocWriter : public TypeLocVisitor<TypeLocWriter> {

   Writer.AddSourceLocation(TL.getLParenLoc(), Record);
   Writer.AddSourceLocation(TL.getRParenLoc(), Record);
 }
+void TypeLocWriter::VisitPipeTypeLoc(PipeTypeLoc TL) {
+  Writer.AddSourceLocation(TL.getKWLoc(), Record);
+}
 
 void ASTWriter::WriteTypeAbbrevs() {
   using namespace llvm;

test/CodeGenOpenCL/pipe_types.cl

+// RUN: %clang_cc1 -emit-llvm -O0 -cl-std=CL2.0 -o - %s | FileCheck %s
+
+// CHECK: %opencl.pipe_t = type opaque
+typedef unsigned char __attribute__((ext_vector_type(3))) uchar3;
+typedef int __attribute__((ext_vector_type(4))) int4;
+
+void test1(read_only pipe int p) {
+// CHECK: define void @test1(%opencl.pipe_t* %p)
+  reserve_id_t rid;
+// CHECK: %rid = alloca %opencl.reserve_id_t
+}
+
+void test2(write_only pipe float p) {
+// CHECK: define void @test2(%opencl.pipe_t* %p)
+}
+
+void test3(read_only pipe const int p) {
+// CHECK: define void @test3(%opencl.pipe_t* %p)
+}
+
+void test4(read_only pipe uchar3 p) {
+// CHECK: define void @test4(%opencl.pipe_t* %p)
+}
+
+void test5(read_only pipe int4 p) {
+// CHECK: define void @test5(%opencl.pipe_t* %p)
+}

test/PCH/ocl_types.h

 // image2d_array_depth_t
 typedef image2d_array_depth_t img2darr_dep_t;
 
+#pragma OPENCL EXTENSION cl_khr_gl_msaa_sharing : enable
 // image2d_msaa_t
 typedef image2d_msaa_t img2dmsaa_t;
 

 // image2d_array_msaa_depth_t
 typedef image2d_array_msaa_depth_t img2darrmsaadep_t;
 
+// pipe specifier
+
+typedef struct _person {
+  int id;
+  const char *name;
+} Person;
+
+void int_pipe_function(pipe int);
+
+void person_pipe_function(pipe Person);
 #endif

test/PCH/ocl_types.cl

 // Test this without pch.
-// RUN: %clang_cc1 -include %S/ocl_types.h -fsyntax-only %s
+// RUN: %clang_cc1 -include %S/ocl_types.h -fsyntax-only %s -cl-std=CL2.0 -D__OPENCL_VERSION__=200
 
 // Test with pch.
-// RUN: %clang_cc1 -x cl -emit-pch -o %t %S/ocl_types.h
-// RUN: %clang_cc1 -include-pch %t -fsyntax-only %s -ast-print
+// RUN: %clang_cc1 -x cl -emit-pch -o %t %S/ocl_types.h -cl-std=CL2.0 -D__OPENCL_VERSION__=200
+// RUN: %clang_cc1 -include-pch %t -fsyntax-only %s -ast-print -cl-std=CL2.0 -D__OPENCL_VERSION__=200
 
 void foo1(img1d_t img);
 

 void foo8(evt_t evt) {
   evt_t loc_evt;
 }
+
+#if __OPENCL_VERSION__ >= 200
+
+void foo9(pipe int P) {
+  int_pipe_function(P);
+}
+
+void foo10(pipe Person P) {
+  person_pipe_function(P);
+}
+
+#endif

test/SemaOpenCL/invalid-pipes-cl2.0.cl

+// RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only -cl-std=CL2.0
+
+void test1(pipe int *p){// expected-error {{pipes packet types cannot be of reference type}}
+}
+void test2(pipe p){// expected-error {{missing actual type specifier for pipe}}
+}
+void test3(int pipe p){// expected-error {{cannot combine with previous 'int' declaration specifier}}
+}

test/SemaOpenCL/pipes-1.2-negative.cl

+// RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only -cl-std=CL1.2
+
+void foo(read_only pipe int p); // expected-error {{expected parameter declarator}} expected-error {{expected ')'}} expected-note {{to match this '('}}

tools/libclang/CIndex.cpp

   return Visit(TL.getValueLoc());
 }
 
+bool CursorVisitor::VisitPipeTypeLoc(PipeTypeLoc TL) {
+  return Visit(TL.getValueLoc());
+}
+
 #define DEFAULT_TYPELOC_IMPL(CLASS, PARENT) \
 bool CursorVisitor::Visit##CLASS##TypeLoc(CLASS##TypeLoc TL) { \
   return Visit##PARENT##Loc(TL); \