[CodeGen] Merge equivalent block copy/helper functions

[ahatanak]

Summary

Currently, clang generates different copy or dispose helper functions for each block literal on the stack if the block has the possibility of being copied to the heap. This patch makes changes to merge equivalent copy and dispose helper functions and reduce code size.

To enable merging equivalent copy/dispose functions, the types and offsets of the captured objects are encoded into the helper function name. This allows IRGen to check whether an equivalent helper function has already been emitted and reuse the function instead of generating a new helper function whenever a block is defined. In addition, the helper functions are marked as linkonce_odr to enable merging helper functions that have the same name across translation units and marked as unnamed_addr to enable the linker's deduplication pass to merge functions that have different names but the same content.

rdar://problem/22950898

[ahatanak]

test/CodeGenCXX/block-byref-cxx-objc.cpp

36

Should the second call to @_Block_object_dispose be an invoke if the destructor can throw? The FIXME in CodeGenFunction::BuildBlockRelease seems to imply that we should consider whether the destructor can throw.

[mgrang]

lib/CodeGen/CGBlocks.cpp

1599

Please use llvm::sort instead of std::sort. See https://llvm.org/docs/CodingStandards.html#beware-of-non-deterministic-sorting-order-of-equal-elements

[ahatanak]

Use llvm::sort.

test/CodeGenCXX/block-byref-cxx-objc.cpp

36

I mean the first call, not the second call. If the call to A's destructor throws when the first object is being destructed, the second object should be destructed on the EH path.

[rjmccall]

lib/CodeGen/CGBlocks.cpp

1644

I forget whether this case has already filtered out trivial copy-constructors, but if not, you should consider doing that here.

1653

This doesn't always have to be a copy constructor. I mean, maybe this procedure works anyway, but the constructor used to copy an object isn't always a copy constructor. Blame constructor templates.

1657

The name of a C++ class is not unique; you need to use the mangler. Ideally, you would find a way to mangle all the C++ types in the context of the same mangler instance so that substitutions could be reused across it.

You also need to check for a type with non-external linkage and make this helper private if you find one. (You can still unique within the translation unit, for what it's worth.)

[ahatanak]

Address review comments.

lib/CodeGen/CGBlocks.cpp

1644

E.Kind is set to CXXRecord only when the copy constructor is non-trivial (or the destructor is non-trivial if this is a destroy helper). Both computeCopyInfoForBlockCapture and computeDestroyInfoForBlockCapture filter out types with trivial copy constructors or destructors.

1653

I've made changes to use the name of the constructor function that is used to copy the capture instead of using the volatility of the copy constructor's argument.

I'm not sure when a function that is not a copy constructor would be used to copy a captured object though. The comment in function captureInBlock in SemaExpr.cpp says that the the blocks spec requires a const copy constructor.

1657

Good catch. test/CodeGenCXX/blocks.cpp checks that helper functions for blocks that capture non-external types have internal linkage.

[rjmccall]

lib/CodeGen/CGBlocks.cpp

496

You only need to do this if you're going to mangle the type name, i.e. if it's actually going to end up as a CXXRecord capture. It should be easy enough to just set this flag above in the clauses where you recognize interesting C++ record captures.

1644

Great.

1653

Okay. I think mangling the type of the capture is probably good enough (and likely to be a little smaller), because different compilations using the same capture type will always use the same constructor. That will include volatile if the captured variable was marked volatile.

The notable case where copy-construction doesn't use a copy constructor is when you have a constructor template like template <class T> ClassName(T &);, which will be preferred over the default copy-constructor for copying non-const objects. It's silly, but it's how it works.

You can mangle the type by just building an ItaniumMangleContext. I think it's better to stably use the Itanium mangling instead of using the target's native mangling.

[ahatanak]

Address review comments.

lib/CodeGen/CGBlocks.cpp

496

I modified the test case in test/CodeGenObjCXX/arc-blocks.mm to check that capturing a trivial C++ class doesn't cause the helper functions to be internal.

[rjmccall]

lib/CodeGen/CGBlocks.cpp

1653

Itanium type manglings are self-delimiting, so you don't actually need this run-length encoding, but it doesn't really hurt, either. Certainly it makes it a lot easier for tools to parse one of these function names.

1691

I feel like this reads a little better if you write the quantity first. Also I think you can drop the underscore because all of your suffices are easy to compute the length of, so a block that captures 3 strong variables can just be 32s40s48s or something like that.

Oh, I guess if you do that you need to do something about how you handle the bit-mask for BlockObject, because that could run into the next number. Would it be better to just break this out into cases? The three current cases are (1) __block variables, which can throw, (2) blocks, and (3) object references in non-ARC modes (which for copy/dispose purposes are just s again, except we use a different entrypoint because we hadn't exposed objc_retain and objc_release yet).

test/CodeGenCXX/block-byref-cxx-objc.cpp

36

Yes, I think we should assume that the block runtime correctly propagates exceptions. The function should not be marked nothrow, but call sites can be marked nothrow depending on what they do.

This won't generally be a code-size problem because (1) we do assume that the ObjC retain/release and weak operations can't throw and (2) C++11 makes destructors noexcept by default.

[ahatanak]

Address review comments.

lib/CodeGen/CGBlocks.cpp

1691

I broke this out into several cases based on the flag's value and whether the constructor or destructor of a C++ type can throw.

test/CodeGenCXX/block-byref-cxx-objc.cpp

36

I defined two functions, cxxDestructorCanThrow and cxxConstructorCanThrow, that are called to find out whether the __block object has a destructor or constructor that can throw.

These functions can return true even when the destructor or constructor cannot throw, but that should be conservatively correct ('invoke' is emitted in some cases even when the function doesn't throw).

[rjmccall]

lib/CodeGen/CGBlocks.cpp

1629

I'm pretty sure this step can't fail.

1642

Can you just ask Sema to check canThrow for the expression and pass it down?

[ahatanak]

Address review comments.

lib/CodeGen/CGBlocks.cpp

1642

Since this changes the existing behavior, I made changes to test/CodeGenCXX/block-byref-cxx-objc.cpp to test it. Previously, IRGen would emit an invoke to call _Block_object_assign when the constructor was marked as noexcept.

[ahatanak]

lib/CodeGen/CGBlocks.cpp

1642

Perhaps I misunderstood your comment, should I have Sema set a flag or something in Expr when it calls a function that can throw?

[rjmccall]

lib/CodeGen/CGBlocks.cpp

1642

Sema has a canThrow predicate that it uses when checking things like the noexcept expression. I was thinking that you could pass that down with the copy expression in the AST for the block capture.

Constructors can have default-argument expressions that can throw even if the constructor itself can't, so it's important to do it that way.

[rjmccall]

You might want to ask Richard on IRC if there are caveats when using that for these purposes.

[ahatanak]

Address review comments.

[ahatanak]

lib/CodeGen/CGBlocks.cpp

1642

I moved the code in lib/Sema/SemaExceptionSpec.cpp that is needed to compute the exception specification to a template class in include/AST so that both Sema and IRGen can use it. Also, I added a call to ResolveExceptionSpec in Sema::CheckCompleteVariableDeclaration to resolve the destructor's exception specification and removed the isUnresolvedExceptionSpec check in CodeGenFunction::cxxDestructorCanThrow. Richard pointed out that the constructor's and destructor's exception specifications should have been resolved by the time IRGen is run.

[ahatanak]

Remove a stale comment and add an assertion to check the destructor's exception specification has been resolved.

[rjmccall]

That is a change that Richard should definitely sign off on. Also, I'm not sure this works — is it really okay to skip the work done by ResolveExceptionSpec in IRGen? What does that mean, that we're just somewhat more conservative than we would otherwise be? And why is this a better solution than just storing whether the copy-expression throws in BlockDecl::Capture?

[ahatanak]

I thought it was okay to skip the work done by ResolveExceptionSpec in IRGen as long as the exception specifications that are needed have already been resolved in Sema. But calling Sema::canThrow in Sema::CheckCompleteVariableDeclaration and storing the result in BlockDecl::Capture is clearly the better solution since it doesn't introduce the complexity introduced in the updated patch.

[ahatanak]

Since BlockVarCopyInits is a map with key VarDecl *, I think we want to add a flag to VarDecl (NonParmVarDeclBits) that indicates whether the copy expression can throw or not. Or is there a reason to store the bit in BlockDecl::Capture instead?

[rjmccall]

In D50152#1191777, @ahatanak wrote:

Since BlockVarCopyInits is a map with key VarDecl *, I think we want to add a flag to VarDecl (NonParmVarDeclBits) that indicates whether the copy expression can throw or not. Or is there a reason to store the bit in BlockDecl::Capture instead?

I was thinking about the non-__block capture case, sorry. For __block variables, I think the values of that map should just be... well, I'd make a struct wrapping it, but basically a PointerIntPair of an Expr* and the canThrow flag.

[ahatanak]

Change the value type of BlockVarCopyInits to PointerIntPair<Expr *, 1, bool>. The boolean flag indicates whether the copy expression can throw. Serialize/deserialize the copy expression and the boolean flag and add a regression test to test/PCH.

[rjmccall]

include/clang/AST/ASTContext.h

248 ↗

(On Diff #159762)

Maybe you should just make a type for this pairing. You can put this documentation there, and the access functions can take and return it.

lib/Sema/SemaDecl.cpp

11851 ↗

(On Diff #159762)

Can we just make this a parameter to setBlockVarCopyInits? The caller always needs to set this correctly, so making it a required parameter makes sense — and it avoids doing the hash-lookup twice.

[ahatanak]

Modify getBlockVarCopyInits and setBlockVarCopyInits to get and set both the copy expression and the boolean flag that indicates whether the expression can throw or not.

[rjmccall]

include/clang/AST/ASTContext.h

158 ↗

(On Diff #159800)

Using a PointerIntPair in the implementation of this is still a reasonable choice. Just make it a proper abstraction, with a constructor with the two arguments and getters for the two fields.

2680 ↗

(On Diff #159800)

I know this is longstanding, but since you're changing all the call sites anyway, please remove the trailing s from these two method names.

248 ↗

(On Diff #159762)

I don't think the typedef is needed here.

lib/AST/ASTContext.cpp

2511 ↗

(On Diff #159800)

I think auto is okay for things like this.

lib/CodeGen/CGBlocks.cpp

1681

I don't think you need to add d to the name of a copy helper. It's a bit weird, but while copying a __block variable can cause its copy helper to run, destroying it immediately afterwards can never cause its destroy helper to run. That's because a newly-copied __block variable always has a reference count of 2: the new reference in the copy and the forwarding reference from the original.

I think that means you can just add a single letter which specifies whether the corresponding __block variable operation is known to be able to throw.

1687

Why rb for a captured block instead of some single-letter thing? You don't need to emulate the structure of the flags here.

1704

The underscore is necessary here because non-trivial destructor strings can start with a number? Worth a comment.

[ahatanak]

Address review comments.

include/clang/AST/ASTContext.h

158 ↗

(On Diff #159800)

I also needed a function that sets the pointer and flag.

lib/CodeGen/CGBlocks.cpp

1681

I added 'd' to the name of the copy helper functions only because IRGen generates different code depending on whether the destructor can throw or not.

For example, if I compile the following code with -DTHROWS, IRGen uses 'invoke' (which jumps to the terminate block) for the calls to _Block_object_dispose on the EH path whereas it uses 'call' if the destructor doesn't throw.

struct S {
  S();
#ifdef THROWS
  ~S() noexcept(false);
#else
  ~S() noexcept(true);
#endif
  S(const S &);
  int a;
};

void test() {
  __block S s0, s1, s2;
  ^{ (void)s0, (void)s1; (void)s2; };
}

It seems like IRGen doesn't have to use 'invoke' when emitting a call to _Block_object_dispose even when the class has a destructor that can throw, if I understood your explanation correctly?

1687

I can use a single letter here, but I'm already using 'b' for byref captures. Perhaps I can use 'o' for non-arc objects, instead of 'r', and use 'r' for byref?

1704

Yes, that's correct.

[rjmccall]

lib/CodeGen/CGBlocks.cpp

1681

Right. It's specifically only true when unwinding after a copy, which is very atypical for C++ code, but nonetheless it's true. We should make the call nounwind in these situations and leave a comment explaining why. Did my explanation make any sense?

1687

That seems reasonable.

[ahatanak]

Address review comments.

lib/CodeGen/CGBlocks.cpp

1681

Yes, it makes sense. Since the reference count is two after the __block variable is copied, calling _Block_object_dispose on it won't cause the destructor to be called.

[rjmccall]

include/clang/AST/ASTContext.h

161 ↗

(On Diff #159926)

These should all just be defined inline.

lib/CodeGen/CGBlocks.cpp

1700

Could you replace these two flags with something more semantic, like telling this function what the context of pushing the cleanup is — basically meaning, are we in the copy helper or the destroy helper? That will let you pull the comment explaining DisposeCannotThrow into this function, where it makes a lot more sense.

[ahatanak]

Define functions inline in the header file.

lib/CodeGen/CGBlocks.cpp

1700

I thought about passing a single flag instead of passing two flags too. If we are going to pass a single flag, should we still use two variables inside the function, EHOnly and DisposeCannotThrow, to maintain the readability of the code?

[rjmccall]

lib/CodeGen/CGBlocks.cpp

1700

Computing EHOnly at the top makes sense to me. DisposeCannotThrow is really only interesting in the one case, and the analysis makes more sense in terms of a ForCopyHelper parameter than it would in terms of this more abstract concept.

[ahatanak]

Replace the two flags, EHOnly and DisposeCannotThrow, passed to pushCaptureCleanup with a single flag ForCopyHelper.

[rjmccall]

Thanks, LGTM.

lib/CodeGen/CGBlocks.h

public:
   /// UsesStret : True if the block uses an stret return.  Mutable
   /// because it gets set later in the block-creation process.
   mutable bool UsesStret : 1;
   
   /// HasCapturedVariableLayout : True if block has captured variables
   /// and their layout meta-data has been generated.
   bool HasCapturedVariableLayout : 1;
 
+  /// Indicates whether an object of a non-external C++ class is captured. This
+  /// bit is used to determine the linkage of the block copy/destroy helper
+  /// functions.
+  bool CapturesNonExternalType : 1;
+
   /// The mapping of allocated indexes within the block.
   llvm::DenseMap<const VarDecl*, Capture> Captures;  
 
   Address LocalAddress;
   llvm::StructType *StructureType;
   const BlockDecl *Block;
   const BlockExpr *BlockExpression;
   CharUnits BlockSize;

lib/CodeGen/CGBlocks.cpp

 //===--- CGBlocks.cpp - Emit LLVM Code for declarations ---------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This contains code to emit blocks.
 //
 //===----------------------------------------------------------------------===//
 
 #include "CGBlocks.h"
+#include "CGCXXABI.h"
 #include "CGDebugInfo.h"
 #include "CGObjCRuntime.h"
 #include "CGOpenCLRuntime.h"
 #include "CodeGenFunction.h"
 #include "CodeGenModule.h"
 #include "ConstantEmitter.h"
 #include "TargetInfo.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/CodeGen/ConstantInitBuilder.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Support/ScopedPrinter.h"
 #include <algorithm>
 #include <cstdio>
 
 using namespace clang;
 using namespace CodeGen;
 
 CGBlockInfo::CGBlockInfo(const BlockDecl *block, StringRef name)
   : Name(name), CXXThisIndex(0), CanBeGlobal(false), NeedsCopyDispose(false),
     HasCXXObject(false), UsesStret(false), HasCapturedVariableLayout(false),
-    LocalAddress(Address::invalid()), StructureType(nullptr), Block(block),
-    DominatingIP(nullptr) {
+    CapturesNonExternalType(false), LocalAddress(Address::invalid()),
+    StructureType(nullptr), Block(block), DominatingIP(nullptr) {
 
   // Skip asm prefix, if any.  'name' is usually taken directly from
   // the mangled name of the enclosing function.
   if (!name.empty() && name[0] == '\01')
     name = name.substr(1);
 }
 
 // Anchor the vtable to this translation unit.
// Block pointers require copy/dispose.  So do Objective-C pointers.
         // used for mrr below.
         lifetime = Qualifiers::OCL_Strong;
       }
 
     // So do types that require non-trivial copy construction.
     } else if (CI.hasCopyExpr()) {
       info.NeedsCopyDispose = true;
       info.HasCXXObject = true;
+      if (!variable->getType()->getAsCXXRecordDecl()->isExternallyVisible())
+        info.CapturesNonExternalType = true;
 
     // So do C structs that require non-trivial copy construction or
     // destruction.
     } else if (variable->getType().isNonTrivialToPrimitiveCopy() ==
                    QualType::PCK_Struct ||
                variable->getType().isDestructedType() ==
                    QualType::DK_nontrivial_c_struct) {
       info.NeedsCopyDispose = true;
 
     // And so do types with destructors.
     } else if (CGM.getLangOpts().CPlusPlus) {
       if (const CXXRecordDecl *record =
             variable->getType()->getAsCXXRecordDecl()) {
         if (!record->hasTrivialDestructor()) {
           info.HasCXXObject = true;
           info.NeedsCopyDispose = true;
+          if (!record->isExternallyVisible())
+            info.CapturesNonExternalType = true;
         }
       }
     }
 
+
     QualType VT = getCaptureFieldType(*CGF, CI);
     CharUnits size = C.getTypeSizeInChars(VT);
     CharUnits align = C.getDeclAlign(variable);
     
     maxFieldAlign = std::max(maxFieldAlign, align);
 
     llvm::Type *llvmType =
       CGM.getTypes().ConvertTypeForMem(VT);
     
     layout.push_back(
         BlockLayoutChunk(align, size, lifetime, &CI, llvmType, VT));
enum class BlockCaptureEntityKind {
   None
 };
 
 /// Represents a captured entity that requires extra operations in order for
 /// this entity to be copied or destroyed correctly.
 struct BlockCaptureManagedEntity {
   BlockCaptureEntityKind Kind;
   BlockFieldFlags Flags;
-  const BlockDecl::Capture &CI;
-  const CGBlockInfo::Capture &Capture;
+  const BlockDecl::Capture *CI;
+  const CGBlockInfo::Capture *Capture;
 
   BlockCaptureManagedEntity(BlockCaptureEntityKind Type, BlockFieldFlags Flags,
                             const BlockDecl::Capture &CI,
                             const CGBlockInfo::Capture &Capture)
-      : Kind(Type), Flags(Flags), CI(CI), Capture(Capture) {}
+      : Kind(Type), Flags(Flags), CI(&CI), Capture(&Capture) {}
+
+  bool operator<(const BlockCaptureManagedEntity &Other) const {
+    return Capture->getOffset() < Other.Capture->getOffset();
+  }
 };
 
 } // end anonymous namespace
 
 static std::pair<BlockCaptureEntityKind, BlockFieldFlags>
 computeCopyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T,
                                const LangOptions &LangOpts) {
   if (CI.getCopyExpr()) {
for (const auto &CI : BlockInfo.getBlockDecl()->captures()) {
     const CGBlockInfo::Capture &Capture = BlockInfo.getCapture(Variable);
     if (Capture.isConstant())
       continue;
 
     auto Info = Predicate(CI, Variable->getType(), LangOpts);
     if (Info.first != BlockCaptureEntityKind::None)
       ManagedCaptures.emplace_back(Info.first, Info.second, CI, Capture);
   }
+
+  // Sort the captures by offset.
+  llvm::sort(ManagedCaptures.begin(), ManagedCaptures.end());
 }
 
 namespace {
 /// Release a __block variable.
 struct CallBlockRelease final : EHScopeStack::Cleanup {
   Address Addr;
   BlockFieldFlags FieldFlags;
   bool LoadBlockVarAddr;
if (LoadBlockVarAddr) {
       BlockVarAddr = Addr.getPointer();
     }
 
     CGF.BuildBlockRelease(BlockVarAddr, FieldFlags);
   }
 };
 } // end anonymous namespace
 
+static std::string getCopyDestroyHelperFuncName(
+    const SmallVectorImpl<BlockCaptureManagedEntity> &Captures,
+    CharUnits BlockAlignment, bool IsCopyHelper, CodeGenModule &CGM) {
+  ASTContext &Ctx = CGM.getContext();
+  std::unique_ptr<ItaniumMangleContext> MC(
+      ItaniumMangleContext::create(Ctx, Ctx.getDiagnostics()));
+
+  std::string Name =
+      IsCopyHelper ? "__copy_helper_block_" : "__destroy_helper_block_";
+  if (CGM.getLangOpts().Exceptions)
+    Name += "e";
+  if (CGM.getCodeGenOpts().ObjCAutoRefCountExceptions)
+    Name += "a";
+  Name += llvm::to_string(BlockAlignment.getQuantity());
+
+  for (const BlockCaptureManagedEntity &E : Captures) {
+    const BlockDecl::Capture &CI = *E.CI;
+    BlockFieldFlags Flags = E.Flags;
+    QualType CaptureTy = CI.getVariable()->getType();
+    Name += "_";
+
+    switch (E.Kind) {
+    case BlockCaptureEntityKind::CXXRecord: {
+      Name += "c";
+      SmallString<256> Str;
+      llvm::raw_svector_ostream Out(Str);
+      MC->mangleTypeName(CaptureTy, Out);
+      Name += llvm::to_string(Str.size()) + Str.c_str();
+      break;
+    }
+    case BlockCaptureEntityKind::ARCWeak:
+      Name += "w";
+      break;
+    case BlockCaptureEntityKind::ARCStrong:
+      Name += "s";
+      break;
+    case BlockCaptureEntityKind::BlockObject: {
+      Name += "b" + llvm::to_string(Flags.getBitMask());
+      const VarDecl *Var = CI.getVariable();
+      // Check if copy can throw.
+      if (IsCopyHelper && CI.isByRef() &&
+          Var->getType()->getAsCXXRecordDecl() && Ctx.getBlockVarCopyInits(Var))
+        Name += "t";
+      break;
+    }
+    case BlockCaptureEntityKind::NonTrivialCStruct: {
+      bool IsVolatile = CaptureTy.isVolatileQualified();
+      CharUnits Alignment =
+          BlockAlignment.alignmentAtOffset(E.Capture->getOffset());
+
+      Name += "n";
+      std::string Str;
+      if (IsCopyHelper)
+        Str = CodeGenFunction::getNonTrivialCopyConstructorStr(
+            CaptureTy, Alignment, IsVolatile, Ctx);
+      else
+        Str = CodeGenFunction::getNonTrivialDestructorStr(CaptureTy, Alignment,
+                                                          IsVolatile, Ctx);
+      Name += llvm::to_string(Str.size()) + "_" + Str;
+      break;
+    }
+    case BlockCaptureEntityKind::None:
+      llvm_unreachable("unexpected block capture kind");
+    }
+
+    Name += "_" + llvm::to_string(E.Capture->getOffset().getQuantity());
+  }
+
+  return Name;
+}
+
 static void pushCaptureCleanup(BlockCaptureEntityKind CaptureKind,
                                Address Field, QualType CaptureType,
                                BlockFieldFlags Flags, bool EHOnly,
                                CodeGenFunction &CGF) {
   switch (CaptureKind) {
   case BlockCaptureEntityKind::CXXRecord:
   case BlockCaptureEntityKind::ARCWeak:
   case BlockCaptureEntityKind::NonTrivialCStruct:
   case BlockCaptureEntityKind::ARCStrong: {
     if (CaptureType.isDestructedType() &&
         (!EHOnly || CGF.needsEHCleanup(CaptureType.isDestructedType()))) {
       CodeGenFunction::Destroyer *Destroyer =
           CaptureKind == BlockCaptureEntityKind::ARCStrong
               ? CodeGenFunction::destroyARCStrongImprecise
               : CGF.getDestroyer(CaptureType.isDestructedType());
       CleanupKind Kind =

 /// The runtime will have previously initialized 'dst' by doing a
 /// bit-copy of 'src'.
 ///
 /// Note that this copies an entire block closure object to the heap;
 /// it should not be confused with a 'byref copy helper', which moves
 /// the contents of an individual __block variable to the heap.
 llvm::Constant *
 CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) {
+  SmallVector<BlockCaptureManagedEntity, 4> CopiedCaptures;
+  findBlockCapturedManagedEntities(blockInfo, getLangOpts(), CopiedCaptures,
+                                   computeCopyInfoForBlockCapture);
+  std::string FuncName =
+      getCopyDestroyHelperFuncName(CopiedCaptures, blockInfo.BlockAlign,
+                                   /*IsCopyHelper*/ true, CGM);
+
+  if (llvm::GlobalValue *Func = CGM.getModule().getNamedValue(FuncName))
+    return Func;
+
   ASTContext &C = getContext();
 
   FunctionArgList args;
   ImplicitParamDecl DstDecl(getContext(), C.VoidPtrTy,
                             ImplicitParamDecl::Other);
   args.push_back(&DstDecl);
   ImplicitParamDecl SrcDecl(getContext(), C.VoidPtrTy,
                             ImplicitParamDecl::Other);
   args.push_back(&SrcDecl);
 
   const CGFunctionInfo &FI =
     CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args);
 
   // FIXME: it would be nice if these were mergeable with things with
   // identical semantics.
   llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
 
   llvm::Function *Fn =
-    llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
-                           "__copy_helper_block_", &CGM.getModule());
+    llvm::Function::Create(LTy, llvm::GlobalValue::LinkOnceODRLinkage,
+                           FuncName, &CGM.getModule());
 
   IdentifierInfo *II
-    = &CGM.getContext().Idents.get("__copy_helper_block_");
+    = &CGM.getContext().Idents.get(FuncName);
 
   FunctionDecl *FD = FunctionDecl::Create(C,
                                           C.getTranslationUnitDecl(),
                                           SourceLocation(),
                                           SourceLocation(), II, C.VoidTy,
                                           nullptr, SC_Static,
                                           false,
                                           false);
 
+  if (blockInfo.CapturesNonExternalType) {
     CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
+  } else {
+    Fn->setVisibility(llvm::GlobalValue::HiddenVisibility);
+    Fn->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
+    CGM.SetLLVMFunctionAttributes(nullptr, FI, Fn);
+    CGM.SetLLVMFunctionAttributesForDefinition(nullptr, Fn);
+  }
 
   StartFunction(FD, C.VoidTy, Fn, FI, args);
   ApplyDebugLocation NL{*this, blockInfo.getBlockExpr()->getLocStart()};
   llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
 
   Address src = GetAddrOfLocalVar(&SrcDecl);
   src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign);
   src = Builder.CreateBitCast(src, structPtrTy, "block.source");
 
   Address dst = GetAddrOfLocalVar(&DstDecl);
   dst = Address(Builder.CreateLoad(dst), blockInfo.BlockAlign);
   dst = Builder.CreateBitCast(dst, structPtrTy, "block.dest");
 
-  SmallVector<BlockCaptureManagedEntity, 4> CopiedCaptures;
-  findBlockCapturedManagedEntities(blockInfo, getLangOpts(), CopiedCaptures,
-                                   computeCopyInfoForBlockCapture);
-
   for (const auto &CopiedCapture : CopiedCaptures) {
-    const BlockDecl::Capture &CI = CopiedCapture.CI;
-    const CGBlockInfo::Capture &capture = CopiedCapture.Capture;
+    const BlockDecl::Capture &CI = *CopiedCapture.CI;
+    const CGBlockInfo::Capture &capture = *CopiedCapture.Capture;
     QualType captureType = CI.getVariable()->getType();
     BlockFieldFlags flags = CopiedCapture.Flags;
 
     unsigned index = capture.getIndex();
     Address srcField = Builder.CreateStructGEP(src, index, capture.getOffset());
     Address dstField = Builder.CreateStructGEP(dst, index, capture.getOffset());
 
     // If there's an explicit copy expression, we do that.

 ///   static void block_destroy_helper(block_t *theBlock);
 ///
 /// Note that this destroys a heap-allocated block closure object;
 /// it should not be confused with a 'byref destroy helper', which
 /// destroys the heap-allocated contents of an individual __block
 /// variable.
 llvm::Constant *
 CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) {
+  SmallVector<BlockCaptureManagedEntity, 4> DestroyedCaptures;
+  findBlockCapturedManagedEntities(blockInfo, getLangOpts(), DestroyedCaptures,
+                                   computeDestroyInfoForBlockCapture);
+  std::string FuncName =
+      getCopyDestroyHelperFuncName(DestroyedCaptures, blockInfo.BlockAlign,
+                                   /*IsCopyHelper*/ false, CGM);
+
+  if (llvm::GlobalValue *Func = CGM.getModule().getNamedValue(FuncName))
+    return Func;
+
   ASTContext &C = getContext();
 
   FunctionArgList args;
   ImplicitParamDecl SrcDecl(getContext(), C.VoidPtrTy,
                             ImplicitParamDecl::Other);
   args.push_back(&SrcDecl);
 
   const CGFunctionInfo &FI =
     CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args);
 
   // FIXME: We'd like to put these into a mergable by content, with
   // internal linkage.
   llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
 
   llvm::Function *Fn =
-    llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
-                           "__destroy_helper_block_", &CGM.getModule());
+    llvm::Function::Create(LTy, llvm::GlobalValue::LinkOnceODRLinkage,
+                           FuncName, &CGM.getModule());
 
   IdentifierInfo *II
-    = &CGM.getContext().Idents.get("__destroy_helper_block_");
+    = &CGM.getContext().Idents.get(FuncName);
 
   FunctionDecl *FD = FunctionDecl::Create(C, C.getTranslationUnitDecl(),
                                           SourceLocation(),
                                           SourceLocation(), II, C.VoidTy,
                                           nullptr, SC_Static,
                                           false, false);
 
+  if (blockInfo.CapturesNonExternalType) {
     CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
+  } else {
+    Fn->setVisibility(llvm::GlobalValue::HiddenVisibility);
+    Fn->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
+    CGM.SetLLVMFunctionAttributes(nullptr, FI, Fn);
+    CGM.SetLLVMFunctionAttributesForDefinition(nullptr, Fn);
+  }
 
   StartFunction(FD, C.VoidTy, Fn, FI, args);
+  markAsIgnoreThreadCheckingAtRuntime(Fn);
+
   ApplyDebugLocation NL{*this, blockInfo.getBlockExpr()->getLocStart()};
 
   llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
 
   Address src = GetAddrOfLocalVar(&SrcDecl);
   src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign);
   src = Builder.CreateBitCast(src, structPtrTy, "block");
 
   CodeGenFunction::RunCleanupsScope cleanups(*this);
 
-  SmallVector<BlockCaptureManagedEntity, 4> DestroyedCaptures;
-  findBlockCapturedManagedEntities(blockInfo, getLangOpts(), DestroyedCaptures,
-                                   computeDestroyInfoForBlockCapture);
-
   for (const auto &DestroyedCapture : DestroyedCaptures) {
-    const BlockDecl::Capture &CI = DestroyedCapture.CI;
-    const CGBlockInfo::Capture &capture = DestroyedCapture.Capture;
+    const BlockDecl::Capture &CI = *DestroyedCapture.CI;
+    const CGBlockInfo::Capture &capture = *DestroyedCapture.Capture;
     BlockFieldFlags flags = DestroyedCapture.Flags;
 
     Address srcField =
       Builder.CreateStructGEP(src, capture.getIndex(), capture.getOffset());
 
     pushCaptureCleanup(DestroyedCapture.Kind, srcField,
                        CI.getVariable()->getType(), flags, /*EHOnly*/ false, *this);
   }

lib/CodeGen/CGNonTrivialStruct.cpp

void visitWithKind(QualType::PrimitiveDefaultInitializeKind PDIK, QualType FT,
 
     Super::visitWithKind(PDIK, FT, FD, CurStructOffset);
   }
 };
 
 struct GenDestructorFuncName : GenUnaryFuncName<GenDestructorFuncName>,
                                DestructedTypeVisitor<GenDestructorFuncName> {
   using Super = DestructedTypeVisitor<GenDestructorFuncName>;
-  GenDestructorFuncName(CharUnits DstAlignment, ASTContext &Ctx)
-      : GenUnaryFuncName<GenDestructorFuncName>("__destructor_", DstAlignment,
+  GenDestructorFuncName(const char *Prefix, CharUnits DstAlignment,
+                        ASTContext &Ctx)
+      : GenUnaryFuncName<GenDestructorFuncName>(Prefix, DstAlignment,
                                                 Ctx) {}
   void visitWithKind(QualType::DestructionKind DK, QualType FT,
                      const FieldDecl *FD, CharUnits CurStructOffset) {
     if (const auto *AT = getContext().getAsArrayType(FT)) {
       visitArray(DK, AT, FT.isVolatileQualified(), FD, CurStructOffset);
       return;
     }
 
void CodeGenFunction::callCStructDefaultConstructor(LValue Dst) {
   Address DstPtr = Dst.getAddress();
   QualType QT = Dst.getType();
   GenDefaultInitializeFuncName GenName(DstPtr.getAlignment(), getContext());
   std::string FuncName = GenName.getName(QT, IsVolatile);
   callSpecialFunction(GenDefaultInitialize(getContext()), FuncName, QT,
                       IsVolatile, *this, std::array<Address, 1>({{DstPtr}}));
 }
 
+std::string
+CodeGenFunction::getNonTrivialCopyConstructorStr(QualType QT,
+                                                 CharUnits Alignment,
+                                                 bool IsVolatile,
+                                                 ASTContext &Ctx) {
+  GenBinaryFuncName<false> GenName("", Alignment, Alignment, Ctx);
+  return GenName.getName(QT, IsVolatile);
+}
+
+std::string
+CodeGenFunction::getNonTrivialDestructorStr(QualType QT, CharUnits Alignment,
+                                            bool IsVolatile, ASTContext &Ctx) {
+  GenDestructorFuncName GenName("", Alignment, Ctx);
+  return GenName.getName(QT, IsVolatile);
+}
+
 void CodeGenFunction::callCStructDestructor(LValue Dst) {
   bool IsVolatile = Dst.isVolatile();
   Address DstPtr = Dst.getAddress();
   QualType QT = Dst.getType();
-  GenDestructorFuncName GenName(DstPtr.getAlignment(), getContext());
+  GenDestructorFuncName GenName("__destructor_", DstPtr.getAlignment(),
+                                getContext());
   std::string FuncName = GenName.getName(QT, IsVolatile);
   callSpecialFunction(GenDestructor(getContext()), FuncName, QT, IsVolatile,
                       *this, std::array<Address, 1>({{DstPtr}}));
 }
 
 void CodeGenFunction::callCStructCopyConstructor(LValue Dst, LValue Src) {
   bool IsVolatile = Dst.isVolatile() || Src.isVolatile();
   Address DstPtr = Dst.getAddress(), SrcPtr = Src.getAddress();

lib/CodeGen/CodeGenFunction.h

Address emitBlockByrefAddress(Address baseAddr,
                                 const llvm::Twine &name);
 
   const BlockByrefInfo &getBlockByrefInfo(const VarDecl *var);
 
   QualType BuildFunctionArgList(GlobalDecl GD, FunctionArgList &Args);
 
   void GenerateCode(GlobalDecl GD, llvm::Function *Fn,
                     const CGFunctionInfo &FnInfo);
+
+  /// Annotate the function with an attribute that disables TSan checking at
+  /// runtime.
+  void markAsIgnoreThreadCheckingAtRuntime(llvm::Function *Fn);
+
   /// Emit code for the start of a function.
   /// \param Loc       The location to be associated with the function.
   /// \param StartLoc  The location of the function body.
   void StartFunction(GlobalDecl GD,
                      QualType RetTy,
                      llvm::Function *Fn,
                      const CGFunctionInfo &FnInfo,
                      const FunctionArgList &Args,
public:
   CGCallee BuildAppleKextVirtualCall(const CXXMethodDecl *MD,
                                      NestedNameSpecifier *Qual,
                                      llvm::Type *Ty);
 
   CGCallee BuildAppleKextVirtualDestructorCall(const CXXDestructorDecl *DD,
                                                CXXDtorType Type,
                                                const CXXRecordDecl *RD);
 
+  // Return the copy constructor name with the prefix "__copy_constructor_"
+  // removed.
+  static std::string getNonTrivialCopyConstructorStr(QualType QT,
+                                                     CharUnits Alignment,
+                                                     bool IsVolatile,
+                                                     ASTContext &Ctx);
+
+  // Return the destructor name with the prefix "__destructor_" removed.
+  static std::string getNonTrivialDestructorStr(QualType QT,
+                                                CharUnits Alignment,
+                                                bool IsVolatile,
+                                                ASTContext &Ctx);
+
   // These functions emit calls to the special functions of non-trivial C
   // structs.
   void defaultInitNonTrivialCStructVar(LValue Dst);
   void callCStructDefaultConstructor(LValue Dst);
   void callCStructDestructor(LValue Dst);
   void callCStructCopyConstructor(LValue Dst, LValue Src);
   void callCStructMoveConstructor(LValue Dst, LValue Src);
   void callCStructCopyAssignmentOperator(LValue Dst, LValue Src);

lib/CodeGen/CodeGenFunction.cpp

static bool endsWithReturn(const Decl* F) {
   if (auto *CS = dyn_cast_or_null<CompoundStmt>(Body)) {
     auto LastStmt = CS->body_rbegin();
     if (LastStmt != CS->body_rend())
       return isa<ReturnStmt>(*LastStmt);
   }
   return false;
 }
 
-static void markAsIgnoreThreadCheckingAtRuntime(llvm::Function *Fn) {
+void CodeGenFunction::markAsIgnoreThreadCheckingAtRuntime(llvm::Function *Fn) {
+  if (SanOpts.has(SanitizerKind::Thread)) {
     Fn->addFnAttr("sanitize_thread_no_checking_at_run_time");
     Fn->removeFnAttr(llvm::Attribute::SanitizeThread);
   }
+}
 
 static bool matchesStlAllocatorFn(const Decl *D, const ASTContext &Ctx) {
   auto *MD = dyn_cast_or_null<CXXMethodDecl>(D);
   if (!MD || !MD->getDeclName().getAsIdentifierInfo() ||
       !MD->getDeclName().getAsIdentifierInfo()->isStr("allocate") ||
       (MD->getNumParams() != 1 && MD->getNumParams() != 2))
     return false;
 
#undef SANITIZER
   if (SanOpts.has(SanitizerKind::Thread)) {
     if (const auto *OMD = dyn_cast_or_null<ObjCMethodDecl>(D)) {
       IdentifierInfo *II = OMD->getSelector().getIdentifierInfoForSlot(0);
       if (OMD->getMethodFamily() == OMF_dealloc ||
           OMD->getMethodFamily() == OMF_initialize ||
           (OMD->getSelector().isUnarySelector() && II->isStr(".cxx_destruct"))) {
         markAsIgnoreThreadCheckingAtRuntime(Fn);
       }
-    } else if (const auto *FD = dyn_cast_or_null<FunctionDecl>(D)) {
-      IdentifierInfo *II = FD->getIdentifier();
-      if (II && II->isStr("__destroy_helper_block_"))
-        markAsIgnoreThreadCheckingAtRuntime(Fn);
     }
   }
 
   // Ignore unrelated casts in STL allocate() since the allocator must cast
   // from void* to T* before object initialization completes. Don't match on the
   // namespace because not all allocators are in std::
   if (D && SanOpts.has(SanitizerKind::CFIUnrelatedCast)) {
     if (matchesStlAllocatorFn(D, getContext()))

test/CodeGen/blocks-1.c

 // RUN: %clang_cc1 %s -emit-llvm -o %t -fblocks
-// RUN: grep "_Block_object_dispose" %t | count 17
-// RUN: grep "__copy_helper_block_" %t | count 14
-// RUN: grep "__destroy_helper_block_" %t | count 14
+// RUN: grep "_Block_object_dispose" %t | count 12
+// RUN: grep "__copy_helper_block_" %t | count 9
+// RUN: grep "__destroy_helper_block_" %t | count 9
 // RUN: grep "__Block_byref_object_copy_" %t | count 2
 // RUN: grep "__Block_byref_object_dispose_" %t | count 2
 // RUN: grep "i32 135)" %t | count 2
-// RUN: grep "_Block_object_assign" %t | count 10
+// RUN: grep "_Block_object_assign" %t | count 5
 
 int printf(const char *, ...);
 
 void test1() {
   __block int a;
   int b=2;
   a=1;
   printf("a is %d, b is %d\n", a, b);

test/CodeGen/blocks.c

 // RUN: %clang_cc1 -triple i386-unknown-unknown %s -emit-llvm -o - -fblocks | FileCheck %s
+
+// CHECK: %[[STRUCT_BLOCK_DESCRIPTOR:.*]] = type { i32, i32 }
+
+// CHECK: @[[BLOCK_DESCRIPTOR_TMP21:.*]] = internal constant { i32, i32, void (i8*, i8*)*, void (i8*)*, i8*, i8* } { i32 0, i32 24, void (i8*, i8*)* @__copy_helper_block_4_b8_20, void (i8*)* @__destroy_helper_block_4_b8_20, i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str, i32 0, i32 0), i8* null }, align 4
+
 void (^f)(void) = ^{};
 
 // rdar://6768379
 int f0(int (^a0)()) {
   return a0(1, 2, 3);
 }
 
 // Verify that attributes on blocks are set correctly.
void *P = ^{
   void *Q = __func__;
 };
 
 void (^test1)(void) = ^(void) {
   __block int i;
   ^ { i = 1; }();
 };
 
+// CHECK-LABEL: define linkonce_odr hidden void @__copy_helper_block_4_b8_20(i8*, i8*) unnamed_addr
+// CHECK: %[[_ADDR:.*]] = alloca i8*, align 4
+// CHECK-NEXT: %[[_ADDR1:.*]] = alloca i8*, align 4
+// CHECK-NEXT: store i8* %0, i8** %[[_ADDR]], align 4
+// CHECK-NEXT: store i8* %1, i8** %[[_ADDR1]], align 4
+// CHECK-NEXT: %[[V2:.*]] = load i8*, i8** %[[_ADDR1]], align 4
+// CHECK-NEXT: %[[BLOCK_SOURCE:.*]] = bitcast i8* %[[V2]] to <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>*
+// CHECK-NEXT: %[[V3:.*]] = load i8*, i8** %[[_ADDR]], align 4
+// CHECK-NEXT: %[[BLOCK_DEST:.*]] = bitcast i8* %[[V3]] to <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>*
+// CHECK-NEXT: %[[V4:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>* %[[BLOCK_SOURCE]], i32 0, i32 5
+// CHECK-NEXT: %[[V5:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>* %[[BLOCK_DEST]], i32 0, i32 5
+// CHECK-NEXT: %[[BLOCKCOPY_SRC:.*]] = load i8*, i8** %[[V4]], align 4
+// CHECK-NEXT: %[[V6:.*]] = bitcast i8** %[[V5]] to i8*
+// CHECK-NEXT: call void @_Block_object_assign(i8* %[[V6]], i8* %[[BLOCKCOPY_SRC]], i32 8)
+// CHECK-NEXT: ret void
+
+// CHECK-LABEL: define linkonce_odr hidden void @__destroy_helper_block_4_b8_20(i8*) unnamed_addr
+// CHECK: %[[_ADDR:.*]] = alloca i8*, align 4
+// CHECK-NEXT: store i8* %0, i8** %[[_ADDR]], align 4
+// CHECK-NEXT: %[[V1:.*]] = load i8*, i8** %[[_ADDR]], align 4
+// CHECK-NEXT: %[[BLOCK:.*]] = bitcast i8* %[[V1]] to <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>*
+// CHECK-NEXT: %[[V2:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>* %[[BLOCK]], i32 0, i32 5
+// CHECK-NEXT: %[[V3:.*]] = load i8*, i8** %[[V2]], align 4
+// CHECK-NEXT: call void @_Block_object_dispose(i8* %[[V3]], i32 8)
+// CHECK-NEXT: ret void
+
 typedef double ftype(double);
 // It's not clear that we *should* support this syntax, but until that decision
 // is made, we should support it properly and not crash.
 ftype ^test2 = ^ftype {
   return 0;
 };
 
 // rdar://problem/8605032

 
 // Ensure that we don't emit helper code in copy/dispose routines for variables
 // that are const-captured.
 void testConstCaptureInCopyAndDestroyHelpers() {
   const int x = 0;
   __block int i;
   (^ { i = x; })();
 }
-// CHECK-LABEL: testConstCaptureInCopyAndDestroyHelpers_block_invoke
+// CHECK-LABEL: define void @testConstCaptureInCopyAndDestroyHelpers(
+// CHECK: %[[BLOCK_DESCRIPTOR:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>* %{{.*}}, i32 0, i32 4
+// CHECK: store %[[STRUCT_BLOCK_DESCRIPTOR]]* bitcast ({ i32, i32, void (i8*, i8*)*, void (i8*)*, i8*, i8* }* @[[BLOCK_DESCRIPTOR_TMP21]] to %[[STRUCT_BLOCK_DESCRIPTOR]]*), %[[STRUCT_BLOCK_DESCRIPTOR]]** %[[BLOCK_DESCRIPTOR]], align 4
 
-// CHECK: @__copy_helper_block
-// CHECK: alloca
-// CHECK-NEXT: alloca
-// CHECK-NEXT: store
-// CHECK-NEXT: store
-// CHECK-NEXT: load
-// CHECK-NEXT: bitcast
-// CHECK-NEXT: load
-// CHECK-NEXT: bitcast
-// CHECK-NEXT: getelementptr
-// CHECK-NEXT: getelementptr
-// CHECK-NEXT: load
-// CHECK-NEXT: bitcast
-// CHECK-NEXT: call void @_Block_object_assign
-// CHECK-NEXT: ret
-
-// CHECK: @__destroy_helper_block
-// CHECK: alloca
-// CHECK-NEXT: store
-// CHECK-NEXT: load
-// CHECK-NEXT: bitcast
-// CHECK-NEXT: getelementptr
-// CHECK-NEXT: load
-// CHECK-NEXT: call void @_Block_object_dispose
-// CHECK-NEXT: ret
+// CHECK-LABEL: define internal void @__testConstCaptureInCopyAndDestroyHelpers_block_invoke

test/CodeGen/sanitize-thread-no-checking-at-run-time.m

 
 // TSAN: initialize{{.*}}) [[ATTR:#[0-9]+]]
 // TSAN: dealloc{{.*}}) [[ATTR:#[0-9]+]]
 // TSAN: cxx_destruct{{.*}}) [[ATTR:#[0-9]+]]
 
 void test2(id x) {
   extern void test2_helper(id (^)(void));
   test2_helper(^{ return x; });
-// TSAN: define internal void @__destroy_helper_block_(i8*) [[ATTR:#[0-9]+]]
+// TSAN: define linkonce_odr hidden void @__destroy_helper_block_8_b3_32(i8*) unnamed_addr [[ATTR:#[0-9]+]]
 }
 
 // TSAN: attributes [[ATTR]] = { noinline nounwind {{.*}} "sanitize_thread_no_checking_at_run_time" {{.*}} }

test/CodeGenCXX/block-byref-cxx-objc.cpp

-// RUN: %clang_cc1 %s -emit-llvm -triple %itanium_abi_triple -o - -fblocks | FileCheck %s
+// RUN: %clang_cc1 %s -std=c++11 -emit-llvm -triple %itanium_abi_triple -o - -fblocks -fexceptions | FileCheck %s
 // rdar://8594790
 
 struct A {
   int x;
   A(const A &);
   A();
-  ~A();
+  ~A() noexcept(false);
 };
 
-int main()
-{
-  __block A BYREF_VAR;
-        ^{ BYREF_VAR.x = 1234; };
+struct B {
+  int x;
+  B(const B &);
+  B();
+  ~B();
+};
+
+int testA() {
+  __block A a0, a1;
+  ^{ a0.x = 1234; a1.x = 5678; };
   return 0;
 }
 
 // CHECK-LABEL: define internal void @__Block_byref_object_copy_
 // CHECK: call {{.*}} @_ZN1AC1ERKS_
 // CHECK-LABEL: define internal void @__Block_byref_object_dispose_
 // CHECK: call {{.*}} @_ZN1AD1Ev
-// CHECK-LABEL: define internal void @__copy_helper_block_
-// CHECK: call {{.*}}void @_Block_object_assign
-// CHECK-LABEL: define internal void @__destroy_helper_block_
-// CHECK: call {{.*}}void @_Block_object_dispose
+
+// CHECK-LABEL: define linkonce_odr hidden void @__copy_helper_block_e8_b8t_32_b8t_40(
+// CHECK: call void @_Block_object_assign(
+// CHECK: invoke void @_Block_object_assign(
+
+// CHECK-LABEL: define linkonce_odr hidden void @__destroy_helper_block_e8_b8_32_b8_40(
+// CHECK: call {{.*}}void @_Block_object_dispose(
+// CHECK: call void @_Block_object_dispose(
+
+int testB() {
+  __block B b0, b1;
+  ^{ b0.x = 1234; b1.x = 5678; };
+  return 0;
+}
+
+// CHECK-LABEL: define internal void @__Block_byref_object_copy_
+// CHECK: call {{.*}} @_ZN1BC1ERKS_
+// CHECK-LABEL: define internal void @__Block_byref_object_dispose_
+// CHECK: call {{.*}} @_ZN1BD1Ev
+
+// CHECK-NOT: define {{.*}} void @__copy_helper_block_
+// CHECK-NOT: define {{.*}} void @__destroy_helper_block_
 
 // rdar://problem/11135650
 namespace test1 {
   struct A { int x; A(); ~A(); };
 
   void test() {
     return;
     __block A a;
   }
 }

test/CodeGenCXX/blocks.cpp

namespace test9 {
   void test() {
     B x;
     use_block(^{
         int y;
         use_block_2(^{ (void)y; }, x);
     });
   }
 }
+
+namespace test10 {
+  // Check that 'v' is included in the copy helper function name to indicate
+  // the constructor taking a volatile parameter is called to copy the captured
+  // object.
+
+  // CHECK-LABEL: define linkonce_odr hidden void @__copy_helper_block_8_c16_ZTSVN6test101BE_32(
+  // CHECK: call void @_ZN6test101BC1ERVKS0_(
+  // CHECK-LABEL: define linkonce_odr hidden void @__destroy_helper_block_8_c16_ZTSVN6test101BE_32(
+  // CHECK: call void @_ZN6test101BD1Ev(
+
+  struct B {
+    int a;
+    B();
+    B(const B &);
+    B(const volatile B &);
+    ~B();
+  };
+
+  void test() {
+    volatile B x;
+    ^{ (void)x; };
+  }
+}
+
+// Copy/dispose helper functions that capture objects of non-external types
+// should have internal linkage.
+
+// CHECK-LABEL: define internal void @__copy_helper_block_8_c22_ZTSN12_GLOBAL__N_11BE_32(
+// CHECK-LABEL: define internal void @__destroy_helper_block_8_c22_ZTSN12_GLOBAL__N_11BE_32(
+
+namespace {
+  struct B {
+    int a;
+    B();
+    B(const B &);
+    ~B();
+  };
+
+  void test() {
+    B x;
+    ^{ (void)x; };
+  }
+}
+
+void callTest() {
+  test();
+}

test/CodeGenCXX/cxx-block-objects.cpp

 {
         A a;
         void (^c)(void) = ((__typeof(^{ a.hello(); }))_Block_copy((const void *)(^{ a.hello(); })));
         c();
         _Block_release((const void *)(c));
         return 0;
 }
 
-// CHECK-LABEL: define internal void @__copy_helper_block_
+// CHECK-LABEL: define linkonce_odr hidden void @__copy_helper_block_
 // CHECK: call void @_ZN1AC1ERKS_
 
 
-// CHECK-LABEL:define internal void @__destroy_helper_block_
+// CHECK-LABEL:define linkonce_odr hidden void @__destroy_helper_block_
 // CHECK: call void @_ZN1AD1Ev

test/CodeGenObjC/arc-blocks.m

 // RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -fblocks -fobjc-arc -fobjc-runtime-has-weak -O2 -disable-llvm-passes -o - %s | FileCheck %s
 // RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -fblocks -fobjc-arc -fobjc-runtime-has-weak -o - %s | FileCheck -check-prefix=CHECK-UNOPT %s
 
+// CHECK: %[[STRUCT_BLOCK_DESCRIPTOR:.*]] = type { i64, i64 }
+// CHECK-UNOPT: %[[STRUCT_BLOCK_DESCRIPTOR:.*]] = type { i64, i64 }
+// CHECK: @[[BLOCK_DESCRIPTOR_TMP9:.*]] = internal constant { i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i64 } { i64 0, i64 40, void (i8*, i8*)* @__copy_helper_block_8_b8_32, void (i8*)* @__destroy_helper_block_8_b8_32, i8* getelementptr inbounds ([6 x i8], [6 x i8]* @{{.*}}, i32 0, i32 0), i64 16 }, align 8
+// CHECK-UNOPT: @{{.*}} = internal constant { i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i64 } { i64 0, i64 40, void (i8*, i8*)* @__copy_helper_block_8_s_32, void (i8*)* @__destroy_helper_block_8_s_32, i8* getelementptr inbounds ([6 x i8], [6 x i8]* @{{.*}}, i32 0, i32 0), i64 256 }, align 8
+// CHECK-UNOPT: @{{.*}} = internal constant { i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i64 } { i64 0, i64 40, void (i8*, i8*)* @__copy_helper_block_8_s_32, void (i8*)* @__destroy_helper_block_8_s_32, i8* getelementptr inbounds ([6 x i8], [6 x i8]* @{{.*}}, i32 0, i32 0), i64 256 }, align 8
+// CHECK-UNOPT: @{{.*}} = internal constant { i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i64 } { i64 0, i64 40, void (i8*, i8*)* @__copy_helper_block_8_s_32, void (i8*)* @__destroy_helper_block_8_s_32, i8* getelementptr inbounds ([6 x i8], [6 x i8]* @{{.*}}, i32 0, i32 0), i64 256 }, align 8
+// CHECK-UNOPT: @{{.*}} = internal constant { i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i64 } { i64 0, i64 40, void (i8*, i8*)* @__copy_helper_block_8_s_32, void (i8*)* @__destroy_helper_block_8_s_32, i8* getelementptr inbounds ([6 x i8], [6 x i8]* @{{.*}}, i32 0, i32 0), i64 256 }, align 8
+// CHECK-UNOPT: @[[BLOCK_DESCRIPTOR_TMP44:.*]] = internal constant { i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i64 } { i64 0, i64 40, void (i8*, i8*)* @__copy_helper_block_8_s_32, void (i8*)* @__destroy_helper_block_8_s_32, i8* getelementptr inbounds ([6 x i8], [6 x i8]* @{{.*}}, i32 0, i32 0), i64 256 }, align 8
+// CHECK: @[[BLOCK_DESCRIPTOR_TMP46:.*]] = internal constant { i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i8* } { i64 0, i64 48, void (i8*, i8*)* @__copy_helper_block_8_s_32, void (i8*)* @__destroy_helper_block_8_s_32, i8* getelementptr inbounds ([6 x i8], [6 x i8]* @{{.*}}, i32 0, i32 0), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @{{.*}}, i32 0, i32 0) }, align 8
+// CHECK: @[[BLOCK_DESCRIPTOR_TMP48:.*]] = internal constant { i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i64 } { i64 0, i64 40, void (i8*, i8*)* @__copy_helper_block_8_b7_32, void (i8*)* @__destroy_helper_block_8_s_32, i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str.47, i32 0, i32 0), i64 256 }, align 8
+
 // This shouldn't crash.
 void test0(id (^maker)(void)) {
   maker();
 }
 
 int (^test1(int x))(void) {
   // CHECK-LABEL:    define i32 ()* @test1(
   // CHECK:      [[X:%.*]] = alloca i32,

 // CHECK-NEXT: [[T0:%.*]] = load i8*, i8** [[SLOTREL]]
 // CHECK-NEXT: call void @objc_release(i8* [[T0]]) [[NUW]], !clang.imprecise_release
 // CHECK-NEXT: [[T0:%.*]] = load i8*, i8** [[X]]
 // CHECK-NEXT: call void @objc_release(i8* [[T0]]) [[NUW]], !clang.imprecise_release
 // CHECK-NEXT: ret void
   extern void test2_helper(id (^)(void));
   test2_helper(^{ return x; });
 
-// CHECK-LABEL:    define internal void @__copy_helper_block_(i8*, i8*) #{{[0-9]+}} {
+// CHECK:    define linkonce_odr hidden void @__copy_helper_block_8_s_32(i8*, i8*) unnamed_addr #{{[0-9]+}} {
 // CHECK:      [[T0:%.*]] = load i8*, i8**
 // CHECK-NEXT: [[SRC:%.*]] = bitcast i8* [[T0]] to [[BLOCK_T]]*
 // CHECK-NEXT: [[T0:%.*]] = load i8*, i8**
 // CHECK-NEXT: [[DST:%.*]] = bitcast i8* [[T0]] to [[BLOCK_T]]*
 // CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[SRC]], i32 0, i32 5
 // CHECK-NEXT: [[T1:%.*]] = load i8*, i8** [[T0]]
 // CHECK-NEXT: [[T2:%.*]] = call i8* @objc_retain(i8* [[T1]]) [[NUW]]
 // CHECK-NEXT: ret void
 
-// CHECK-LABEL:    define internal void @__destroy_helper_block_(i8*) #{{[0-9]+}} {
+
+// CHECK:    define linkonce_odr hidden void @__destroy_helper_block_8_s_32(i8*) unnamed_addr #{{[0-9]+}} {
 // CHECK:      [[T0:%.*]] = load i8*, i8**
 // CHECK-NEXT: [[T1:%.*]] = bitcast i8* [[T0]] to [[BLOCK_T]]*
 // CHECK-NEXT: [[T2:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[T1]], i32 0, i32 5
 // CHECK-NEXT: [[T3:%.*]] = load i8*, i8** [[T2]]
 // CHECK-NEXT: call void @objc_release(i8* [[T3]])
 // CHECK-NEXT: ret void
 }
 
void test4(void) {
 
   // CHECK-LABEL:    define internal void @__test4_block_invoke
   // CHECK:      [[SLOT:%.*]] = getelementptr inbounds {{.*}}, i32 0, i32 6
   // CHECK-NEXT: [[T0:%.*]] = load i8*, i8** [[SLOT]], align 8
   // CHECK-NEXT: store i8* null, i8** [[SLOT]],
   // CHECK-NEXT: call void @objc_release(i8* [[T0]])
   // CHECK-NEXT: ret void
 
-  // CHECK-LABEL:    define internal void @__copy_helper_block_.{{[0-9]+}}(i8*, i8*) #{{[0-9]+}} {
+  // CHECK-LABEL:    define linkonce_odr hidden void @__copy_helper_block_8_b8_32(i8*, i8*) unnamed_addr #{{[0-9]+}} {
   // CHECK:      call void @_Block_object_assign(i8* {{%.*}}, i8* {{%.*}}, i32 8)
 
-  // CHECK-LABEL:    define internal void @__destroy_helper_block_.{{[0-9]+}}(i8*) #{{[0-9]+}} {
+  // CHECK-LABEL:    define linkonce_odr hidden void @__destroy_helper_block_8_b8_32(i8*) unnamed_addr #{{[0-9]+}} {
   // CHECK:      call void @_Block_object_dispose(i8* {{%.*}}, i32 8)
 }
 
 void test5(void) {
   extern id test5_source(void);
   void test5_helper(void (^)(void));
   __unsafe_unretained id var = test5_source();
   test5_helper(^{ (void) var; });
void test6(void) {
   // CHECK:      [[SLOT:%.*]] = getelementptr inbounds [[BYREF_T]], [[BYREF_T]]* [[VAR]], i32 0, i32 6
   // CHECK-NEXT: [[T0:%.*]] = call i8* @test6_source()
   // CHECK-NEXT: [[T1:%.*]] = call i8* @objc_retainAutoreleasedReturnValue(i8* [[T0]])
   // CHECK-NEXT: call i8* @objc_initWeak(i8** [[SLOT]], i8* [[T1]])
   // CHECK-NEXT: call void @objc_release(i8* [[T1]])
   // CHECK-NEXT: [[SLOT:%.*]] = getelementptr inbounds [[BYREF_T]], [[BYREF_T]]* [[VAR]], i32 0, i32 6
   // 0x42800000 - has signature, copy/dispose helpers, as well as BLOCK_HAS_EXTENDED_LAYOUT
   // CHECK:      store i32 -1040187392,
+  // CHECK: %[[BLOCK_DESCRIPTOR:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8* }>* %{{.*}}, i32 0, i32 4
+// CHECK: store %[[STRUCT_BLOCK_DESCRIPTOR]]* bitcast ({ i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i64 }* @[[BLOCK_DESCRIPTOR_TMP9]] to %[[STRUCT_BLOCK_DESCRIPTOR]]*), %[[STRUCT_BLOCK_DESCRIPTOR]]** %[[BLOCK_DESCRIPTOR]], align 8
   // CHECK:      [[T0:%.*]] = bitcast [[BYREF_T]]* [[VAR]] to i8*
   // CHECK-NEXT: store i8* [[T0]], i8**
   // CHECK:      call void @test6_helper(
   // CHECK:      [[T0:%.*]] = bitcast [[BYREF_T]]* [[VAR]] to i8*
   // CHECK-NEXT: call void @_Block_object_dispose(i8* [[T0]], i32 8)
   // CHECK-NEXT: call void @objc_destroyWeak(i8** [[SLOT]])
   // CHECK-NEXT: [[VARPTR2:%.*]] = bitcast [[BYREF_T]]* [[VAR]] to i8*
   // CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 48, i8* [[VARPTR2]])
// CHECK: store %[[STRUCT_BLOCK_DESCRIPTOR]]* bitcast ({ i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i64 }* @[[BLOCK_DESCRIPTOR_TMP9]] to %[[STRUCT_BLOCK_DESCRIPTOR]]*), %[[STRUCT_BLOCK_DESCRIPTOR]]** %[[BLOCK_DESCRIPTOR]], align 8
   // CHECK-LABEL:    define internal void @__Block_byref_object_dispose_.{{[0-9]+}}(i8*) #{{[0-9]+}} {
   // CHECK:      [[T0:%.*]] = getelementptr inbounds [[BYREF_T]], [[BYREF_T]]* {{%.*}}, i32 0, i32 6
   // CHECK-NEXT: call void @objc_destroyWeak(i8** [[T0]])
 
   // CHECK-LABEL:    define internal void @__test6_block_invoke
   // CHECK:      [[SLOT:%.*]] = getelementptr inbounds {{.*}}, i32 0, i32 6
   // CHECK-NEXT: call i8* @objc_storeWeak(i8** [[SLOT]], i8* null)
   // CHECK-NEXT: ret void
-
-  // CHECK-LABEL:    define internal void @__copy_helper_block_.{{[0-9]+}}(i8*, i8*) #{{[0-9]+}} {
-  // 0x8 - FIELD_IS_BYREF (no FIELD_IS_WEAK because clang in control)
-  // CHECK:      call void @_Block_object_assign(i8* {{%.*}}, i8* {{%.*}}, i32 8)
-
-  // CHECK-LABEL:    define internal void @__destroy_helper_block_.{{[0-9]+}}(i8*) #{{[0-9]+}} {
-  // 0x8 - FIELD_IS_BYREF (no FIELD_IS_WEAK because clang in control)
-  // CHECK:      call void @_Block_object_dispose(i8* {{%.*}}, i32 8)
 }
 
 void test7(void) {
   id test7_source(void);
   void test7_helper(void (^)(void));
   void test7_consume(id);
   __weak id var = test7_source();
   test7_helper(^{ test7_consume(var); });
void test7(void) {
 
   // CHECK-LABEL:    define internal void @__test7_block_invoke
   // CHECK:      [[SLOT:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* {{%.*}}, i32 0, i32 5
   // CHECK-NEXT: [[T0:%.*]] = call i8* @objc_loadWeakRetained(i8** [[SLOT]])
   // CHECK-NEXT: call void @test7_consume(i8* [[T0]])
   // CHECK-NEXT: call void @objc_release(i8* [[T0]])
   // CHECK: ret void
 
-  // CHECK-LABEL:    define internal void @__copy_helper_block_.{{[0-9]+}}(i8*, i8*) #{{[0-9]+}} {
+  // CHECK-LABEL:    define linkonce_odr hidden void @__copy_helper_block_8_w_32(i8*, i8*) unnamed_addr #{{[0-9]+}} {
   // CHECK:      getelementptr
   // CHECK-NEXT: getelementptr
   // CHECK-NEXT: call void @objc_copyWeak(
 
-  // CHECK-LABEL:    define internal void @__destroy_helper_block_.{{[0-9]+}}(i8*) #{{[0-9]+}} {
+  // CHECK-LABEL:    define linkonce_odr hidden void @__destroy_helper_block_8_w_32(i8*) unnamed_addr #{{[0-9]+}} {
   // CHECK:      getelementptr
   // CHECK-NEXT: call void @objc_destroyWeak(
 }
 
 @interface Test8 @end
 @implementation Test8
 - (void) test {
 // CHECK:    define internal void @"\01-[Test8 test]"

 
 void test18(id x) {
 // CHECK-UNOPT-LABEL:    define void @test18(
 // CHECK-UNOPT:      [[X:%.*]] = alloca i8*,
 // CHECK-UNOPT-NEXT: [[BLOCK:%.*]] = alloca [[BLOCK_T:<{.*}>]],
 // CHECK-UNOPT-NEXT: store i8* null, i8** [[X]]
 // CHECK-UNOPT-NEXT: call void @objc_storeStrong(i8** [[X]], 
 // CHECK-UNOPT-NEXT: [[SLOTREL:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[BLOCK]], i32 0, i32 5
+// CHECK-UNOPT: %[[BLOCK_DESCRIPTOR:.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[BLOCK]], i32 0, i32 4
+// CHECK-UNOPT: store %[[STRUCT_BLOCK_DESCRIPTOR]]* bitcast ({ i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i64 }* @[[BLOCK_DESCRIPTOR_TMP44]] to %[[STRUCT_BLOCK_DESCRIPTOR]]*), %[[STRUCT_BLOCK_DESCRIPTOR]]** %[[BLOCK_DESCRIPTOR]], align 8
 // CHECK-UNOPT:      [[SLOT:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[BLOCK]], i32 0, i32 5
 // CHECK-UNOPT-NEXT: [[T0:%.*]] = load i8*, i8** [[X]],
 // CHECK-UNOPT-NEXT: [[T1:%.*]] = call i8* @objc_retain(i8* [[T0]])
 // CHECK-UNOPT-NEXT: store i8* [[T1]], i8** [[SLOT]],
 // CHECK-UNOPT-NEXT: bitcast
 // CHECK-UNOPT-NEXT: call void @test18_helper(
 // CHECK-UNOPT-NEXT: call void @objc_storeStrong(i8** [[SLOTREL]], i8* null) [[NUW:#[0-9]+]]
 // CHECK-UNOPT-NEXT: call void @objc_storeStrong(i8** [[X]], i8* null) [[NUW]]
 // CHECK-UNOPT-NEXT: ret void
   extern void test18_helper(id (^)(void));
   test18_helper(^{ return x; });
-
-// CHECK-UNOPT-LABEL:    define internal void @__copy_helper_block_.{{[0-9]+}}(i8*, i8*) #{{[0-9]+}} {
-// CHECK-UNOPT:      [[T0:%.*]] = load i8*, i8**
-// CHECK-UNOPT-NEXT: [[SRC:%.*]] = bitcast i8* [[T0]] to [[BLOCK_T]]*
-// CHECK-UNOPT-NEXT: [[T0:%.*]] = load i8*, i8**
-// CHECK-UNOPT-NEXT: [[DST:%.*]] = bitcast i8* [[T0]] to [[BLOCK_T]]*
-// CHECK-UNOPT-NEXT: [[T0:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[SRC]], i32 0, i32 5
-// CHECK-UNOPT-NEXT: [[T1:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[DST]], i32 0, i32 5
-// CHECK-UNOPT-NEXT: [[T2:%.*]] = load i8*, i8** [[T0]]
-// CHECK-UNOPT-NEXT: store i8* null, i8** [[T1]]
-// CHECK-UNOPT-NEXT: call void @objc_storeStrong(i8** [[T1]], i8* [[T2]]) [[NUW]]
-// CHECK-UNOPT-NEXT: ret void
-
-// CHECK-UNOPT-LABEL:    define internal void @__destroy_helper_block_.{{[0-9]+}}(i8*) #{{[0-9]+}} {
-// CHECK-UNOPT:      [[T0:%.*]] = load i8*, i8**
-// CHECK-UNOPT-NEXT: [[T1:%.*]] = bitcast i8* [[T0]] to [[BLOCK_T]]*
-// CHECK-UNOPT-NEXT: [[T2:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[T1]], i32 0, i32 5
-// CHECK-UNOPT-NEXT: call void @objc_storeStrong(i8** [[T2]], i8* null)
-// CHECK-UNOPT-NEXT: ret void
 }
 
 // Ensure that we don't emit helper code in copy/dispose routines for variables
 // that are const-captured.
 void testUnsafeUnretainedLifetimeInCopyAndDestroyHelpers(id x, id y) {
   id __unsafe_unretained unsafeObject = x;
   (^ { testUnsafeUnretainedLifetimeInCopyAndDestroyHelpers(x, unsafeObject); })();
 }
 
-// CHECK-LABEL: testUnsafeUnretainedLifetimeInCopyAndDestroyHelpers_block_invoke
-// CHECK-UNOPT-LABEL: testUnsafeUnretainedLifetimeInCopyAndDestroyHelpers_block_invoke
+// CHECK-LABEL: define void @testUnsafeUnretainedLifetimeInCopyAndDestroyHelpers
+// %[[BLOCK_DESCRIPTOR:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8* }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8* }>* %{{.*}}, i32 0, i32 4
+// store %[[STRUCT_BLOCK_DESCRIPTOR]]* bitcast ({ i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i8* }* @[[BLOCK_DESCRIPTOR_TMP46]] to %[[STRUCT_BLOCK_DESCRIPTOR]]*), %[[STRUCT_BLOCK_DESCRIPTOR]]** %[[BLOCK_DESCRIPTOR]], align 8
 
-// CHECK-UNOPT: @__copy_helper_block
-// CHECK-UNOPT: alloca
-// CHECK-UNOPT-NEXT: alloca
-// CHECK-UNOPT-NEXT: store
-// CHECK-UNOPT-NEXT: store
-// CHECK-UNOPT-NEXT: load
-// CHECK-UNOPT-NEXT: bitcast
-// CHECK-UNOPT-NEXT: load
-// CHECK-UNOPT-NEXT: bitcast
-// CHECK-UNOPT-NEXT: getelementptr
-// CHECK-UNOPT-NEXT: getelementptr
-// CHECK-UNOPT-NEXT: load
-// CHECK-UNOPT-NEXT: store
-// CHECK-UNOPT-NEXT: call void @objc_storeStrong
-// CHECK-UNOPT-NEXT: ret
-
-// CHECK-UNOPT: @__destroy_helper_block
-// CHECK-UNOPT: alloca
-// CHECK-UNOPT-NEXT: store
-// CHECK-UNOPT-NEXT: load
-// CHECK-UNOPT-NEXT: bitcast
-// CHECK-UNOPT-NEXT: getelementptr
-// CHECK-UNOPT-NEXT: call void @objc_storeStrong
-// CHECK-UNOPT-NEXT: ret
+// CHECK-LABEL: define internal void @__testUnsafeUnretainedLifetimeInCopyAndDestroyHelpers_block_invoke
+// CHECK-UNOPT-LABEL: define internal void @__testUnsafeUnretainedLifetimeInCopyAndDestroyHelpers_block_invoke
 
 // rdar://13588325
 void test19_sink(void (^)(int));
 void test19(void (^b)(void)) {
 // CHECK-LABEL:    define void @test19(
 //   Prologue.
 // CHECK:      [[B:%.*]] = alloca void ()*,
 // CHECK-NEXT: [[BLOCK:%.*]] = alloca [[BLOCK_T:<{.*}>]],
 // CHECK-NEXT: [[T0:%.*]] = bitcast void ()* {{%.*}} to i8*
 // CHECK-NEXT: [[T1:%.*]] = call i8* @objc_retain(i8* [[T0]])
 // CHECK-NEXT: [[T2:%.*]] = bitcast i8* [[T1]] to void ()*
 // CHECK-NEXT: store void ()* [[T2]], void ()** [[B]]
 
 //   Block setup.  We skip most of this.  Note the bare retain.
 // CHECK-NEXT: [[SLOTREL:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[BLOCK]], i32 0, i32 5
+// CHECK: %[[BLOCK_DESCRIPTOR:.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[BLOCK]], i32 0, i32 4
+// CHECK: store %[[STRUCT_BLOCK_DESCRIPTOR]]* bitcast ({ i64, i64, void (i8*, i8*)*, void (i8*)*, i8*, i64 }* @[[BLOCK_DESCRIPTOR_TMP48]] to %[[STRUCT_BLOCK_DESCRIPTOR]]*), %[[STRUCT_BLOCK_DESCRIPTOR]]** %[[BLOCK_DESCRIPTOR]], align 8
 // CHECK:      [[SLOT:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[BLOCK]], i32 0, i32 5
 // CHECK-NEXT: [[T0:%.*]] = load void ()*, void ()** [[B]],
 // CHECK-NEXT: [[T1:%.*]] = bitcast void ()* [[T0]] to i8*
 // CHECK-NEXT: [[T2:%.*]] = call i8* @objc_retain(i8* [[T1]])
 // CHECK-NEXT: [[T3:%.*]] = bitcast i8* [[T2]] to void ()*
 // CHECK-NEXT: store void ()* [[T3]], void ()** [[SLOT]],
 //   Call.
 // CHECK-NEXT: [[T0:%.*]] = bitcast [[BLOCK_T]]* [[BLOCK]] to void (i32)*

 // CHECK-UNOPT-NEXT: [[BLOCK:%.*]] = alloca <[[BLOCKTY:.*]]>
 // CHECK-UNOPT: [[CAPTUREFIELD:%.*]] = getelementptr inbounds <[[BLOCKTY]]>, <[[BLOCKTY]]>* [[BLOCK]], i32 0, i32 5
 // CHECK-UNOPT: [[BLOCKCAPTURED:%.*]] = getelementptr inbounds <[[BLOCKTY]]>, <[[BLOCKTY]]>* [[BLOCK]], i32 0, i32 5
 // CHECK-UNOPT: [[CAPTURED:%.*]] = load i8*, i8** [[XADDR]]
 // CHECK-UNOPT: [[RETAINED:%.*]] = call i8* @objc_retain(i8* [[CAPTURED]])
 // CHECK-UNOPT: store i8* [[RETAINED]], i8** [[BLOCKCAPTURED]]
 // CHECK-UNOPT: call void @objc_storeStrong(i8** [[CAPTUREFIELD]], i8* null)
 
-// CHECK-LABEL: define internal void @__copy_helper_block
-// CHECK: [[BLOCKSOURCE:%.*]] = bitcast i8* %{{.*}} to <[[BLOCKTY]]>*
-// CHECK: [[CAPTUREFIELD:%.*]] = getelementptr inbounds <[[BLOCKTY]]>, <[[BLOCKTY]]>* [[BLOCKSOURCE]], i32 0, i32 5
-// CHECK: [[BLOCKCOPYSRC:%.*]] = load i8*, i8** [[CAPTUREFIELD]]
-// CHECK: call i8* @objc_retain(i8* [[BLOCKCOPYSRC]])
-
 void test20_callee(void (^)());
 void test20(const id x) {
   test20_callee(^{ (void)x; });
 }
 
 // CHECK: attributes [[NUW]] = { nounwind }
 // CHECK-UNOPT: attributes [[NUW]] = { nounwind }

test/CodeGenObjC/debug-info-block-helper.m

 // REQUIRES: x86-registered-target
 // RUN: %clang_cc1 -emit-llvm -fblocks -debug-info-kind=limited -triple x86_64-apple-darwin10 -fobjc-runtime=macosx-fragile-10.5 %s -o - | FileCheck %s
 extern void foo(void(^)(void));
 
-// CHECK: !DISubprogram(name: "__destroy_helper_block_"
+// CHECK: !DISubprogram(name: "__destroy_helper_block_8_b3_32_b8_40_b8_48"
 
 @interface NSObject {
   struct objc_object *isa;
 }
 @end
 
 @interface A:NSObject @end
 @implementation A

test/CodeGenObjC/debug-info-blocks.m

 
 @implementation A
 
 - (id)init
 {
     if ((self = [super init])) {
       // CHECK-DAG: [[DBG_LINE]] = !DILocation(line: 0, scope: ![[COPY_SP:[0-9]+]])
       // CHECK-DAG: [[COPY_LINE]] = !DILocation(line: [[@LINE+7]], scope: ![[COPY_SP:[0-9]+]])
-      // CHECK-DAG: [[COPY_SP]] = distinct !DISubprogram(name: "__copy_helper_block_"
+      // CHECK-DAG: [[COPY_SP]] = distinct !DISubprogram(name: "__copy_helper_block_8_b3_32"
       // CHECK-DAG: [[DESTROY_LINE]] = !DILocation(line: [[@LINE+5]], scope: ![[DESTROY_SP:[0-9]+]])
-      // CHECK-DAG: [[DESTROY_SP]] = distinct !DISubprogram(name: "__destroy_helper_block_"
+      // CHECK-DAG: [[DESTROY_SP]] = distinct !DISubprogram(name: "__destroy_helper_block_8_b3_32"
       // CHECK-DAG: !DILocalVariable(arg: 1, scope: ![[COPY_SP]], {{.*}}, flags: DIFlagArtificial)
       // CHECK-DAG: !DILocalVariable(arg: 2, scope: ![[COPY_SP]], {{.*}}, flags: DIFlagArtificial)
       // CHECK-DAG: !DILocalVariable(arg: 1, scope: ![[DESTROY_SP]], {{.*}}, flags: DIFlagArtificial)
       run(^{
           // CHECK-DAG: ![[SELF]] = !DILocalVariable(name: "self", scope:{{.*}}, line: [[@LINE+4]],
           // CHECK-DAG: ![[D]] = !DILocalVariable(name: "d", scope:{{.*}}, line: [[@LINE+1]],
           NSMutableDictionary *d = [[NSMutableDictionary alloc] init]; 
           ivar = 42 + (int)[d count];

test/CodeGenObjC/mrc-weak.m

 // CHECK-NEXT:  [[T1:%.*]] = bitcast i8* [[T0]] to [[FOO]]*
 // CHECK-NEXT:  [[T2:%.*]] = bitcast [[FOO]]** [[P]] to i8**
 // CHECK-NEXT:  [[T3:%.*]] = bitcast [[FOO]]* [[T1]] to i8*
 // CHECK-NEXT:  call i8* @objc_initWeak(i8** [[T2]], i8* [[T3]])
 // CHECK:       call void @objc_copyWeak
 // CHECK:       call void @use_block
 // CHECK:       call void @objc_destroyWeak
 
-// CHECK-LABEL: define internal void @__copy_helper_block
+// CHECK-LABEL: define linkonce_odr hidden void @__copy_helper_block
 // CHECK:       @objc_copyWeak
 
-// CHECK-LABEL: define internal void @__destroy_helper_block
+// CHECK-LABEL: define linkonce_odr hidden void @__destroy_helper_block
 // CHECK:       @objc_destroyWeak
 
 void test8(void) {
   __block __weak Foo *p = get_object();
   use_block(^{ [p run ]; });
 }
 // CHECK-LABEL: define void @test8
 // CHECK:       call i8* @objc_initWeak
 // CHECK-NOT:   call void @objc_copyWeak
 // CHECK:       call void @use_block
 // CHECK:       call void @objc_destroyWeak
 
 // CHECK-LABEL: define internal void @__Block_byref_object_copy
 // CHECK:       call void @objc_moveWeak
 
 // CHECK-LABEL: define internal void @__Block_byref_object_dispose
 // CHECK:       call void @objc_destroyWeak
 
 // CHECK-LABEL: define void @test9_baseline()
-// CHECK:       define internal void @__copy_helper
-// CHECK:       define internal void @__destroy_helper
+// CHECK:       define linkonce_odr hidden void @__copy_helper
+// CHECK:       define linkonce_odr hidden void @__destroy_helper
 void test9_baseline(void) {
   Foo *p = get_object();
   use_block(^{ [p run]; });
 }
 
 // CHECK-LABEL: define void @test9()
-// CHECK-NOT:   define internal void @__copy_helper
-// CHECK-NOT:   define internal void @__destroy_helper
+// CHECK-NOT:   define linkonce_odr hidden void @__copy_helper
+// CHECK-NOT:   define linkonce_odr hidden void @__destroy_helper
 // CHECK:       define void @test9_fin()
 void test9(void) {
   __unsafe_unretained Foo *p = get_object();
   use_block(^{ [p run]; });
 }
 void test9_fin() {}
 
 // CHECK-LABEL: define void @test10()
-// CHECK-NOT:   define internal void @__copy_helper
-// CHECK-NOT:   define internal void @__destroy_helper
+// CHECK-NOT:   define linkonce_odr hidden void @__copy_helper
+// CHECK-NOT:   define linkonce_odr hidden void @__destroy_helper
 // CHECK:       define void @test10_fin()
 void test10(void) {
   typedef __unsafe_unretained Foo *UnsafeFooPtr;
   UnsafeFooPtr p = get_object();
   use_block(^{ [p run]; });
 }
 void test10_fin() {}

test/CodeGenObjC/strong-in-c-struct.m

 
 // CHECK: define void @test_block_capture_Strong()
 // CHECK: call void @__default_constructor_8_s16(
 // CHECK: call void @__copy_constructor_8_8_t0w16_s16(
 // CHECK: call void @__destructor_8_s16(
 // CHECK: call void @__destructor_8_s16(
 // CHECK: ret void
 
-// CHECK: define internal void @__copy_helper_block_.1(i8*, i8*)
+// CHECK: define linkonce_odr hidden void @__copy_helper_block_8_n13_8_8_t0w16_s16_32(i8*, i8*)
 // CHECK: call void @__copy_constructor_8_8_t0w16_s16(
 // CHECK: ret void
 
-// CHECK: define internal void @__destroy_helper_block_.2(
+// CHECK: define linkonce_odr hidden void @__destroy_helper_block_8_n5_8_s16_32(
 // CHECK: call void @__destructor_8_s16(
 // CHECK: ret void
 
 void test_block_capture_Strong(void) {
   Strong t;
   BlockTy b = ^(){ (void)t; };
 }
 

test/CodeGenObjCXX/arc-blocks.mm

 // RUN: %clang_cc1 -std=gnu++98 -triple x86_64-apple-darwin10 -emit-llvm -fobjc-runtime-has-weak -fblocks -fobjc-arc -fexceptions -fobjc-arc-exceptions -o - %s | FileCheck -check-prefix CHECK %s
 // RUN: %clang_cc1 -std=gnu++98 -triple x86_64-apple-darwin10 -emit-llvm -fobjc-runtime-has-weak -fblocks -fobjc-arc -fexceptions -fobjc-arc-exceptions -O1 -o - %s | FileCheck -check-prefix CHECK-O1 %s
+// RUN: %clang_cc1 -std=gnu++98 -triple x86_64-apple-darwin10 -emit-llvm -fobjc-runtime-has-weak -fblocks -fobjc-arc -o - %s | FileCheck -check-prefix CHECK-NOEXCP %s
 
 // CHECK: [[A:.*]] = type { i64, [10 x i8*] }
 // CHECK: %[[STRUCT_TEST1_S0:.*]] = type { i32 }
+// CHECK: %[[STRUCT_TRIVIAL_INTERNAL:.*]] = type { i32 }
 // CHECK: %[[STRUCT_BLOCK_DESCRIPTOR:.*]] = type { i64, i64 }
 
 // CHECK: [[LAYOUT0:@.*]] = private unnamed_addr constant [3 x i8] c" 9\00"
 
 // rdar://13045269
 // If a __block variable requires extended layout information *and*
 // a copy/dispose helper, be sure to adjust the offsets used in copy/dispose.
 namespace test0 {
namespace test0 {
   // CHECK-NEXT: call void @_ZN5test01AD1Ev([[A]]* [[T1]])
   // CHECK-NEXT: ret void
 }
 
 namespace test1 {
 
 // Check that copy/dispose helper functions are exception safe.
 
-// CHECK-LABEL: define internal void @__copy_helper_block_(
-// CHECK: %[[BLOCK_SOURCE:.*]] = bitcast i8* %{{.*}} to <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>*
-// CHECK: %[[BLOCK_DEST:.*]] = bitcast i8* %{{.*}} to <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>*
+// CHECK-LABEL: define linkonce_odr hidden void @__copy_helper_block_ea8_s_32_b8_40_w_48_c15_ZTSN5test12S0E_56_c15_ZTSN5test12S0E_60(
+// CHECK: %[[BLOCK_SOURCE:.*]] = bitcast i8* %{{.*}} to <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>*
+// CHECK: %[[BLOCK_DEST:.*]] = bitcast i8* %{{.*}} to <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>*
 
-// CHECK: %[[V4:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK_SOURCE]], i32 0, i32 6
-// CHECK: %[[V5:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK_DEST]], i32 0, i32 6
+// CHECK: %[[V9:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK_SOURCE]], i32 0, i32 5
+// CHECK: %[[V10:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK_DEST]], i32 0, i32 5
+// CHECK: %[[BLOCKCOPY_SRC2:.*]] = load i8*, i8** %[[V9]], align 8
+// CHECK: store i8* null, i8** %[[V10]], align 8
+// CHECK: call void @objc_storeStrong(i8** %[[V10]], i8* %[[BLOCKCOPY_SRC2]])
+
+// CHECK: %[[V4:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK_SOURCE]], i32 0, i32 6
+// CHECK: %[[V5:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK_DEST]], i32 0, i32 6
 // CHECK: %[[BLOCKCOPY_SRC:.*]] = load i8*, i8** %[[V4]], align 8
 // CHECK: %[[V6:.*]] = bitcast i8** %[[V5]] to i8*
 // CHECK: call void @_Block_object_assign(i8* %[[V6]], i8* %[[BLOCKCOPY_SRC]], i32 8)
 
-// CHECK: %[[V7:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK_SOURCE]], i32 0, i32 7
-// CHECK: %[[V8:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK_DEST]], i32 0, i32 7
+// CHECK: %[[V7:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK_SOURCE]], i32 0, i32 7
+// CHECK: %[[V8:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK_DEST]], i32 0, i32 7
 // CHECK: call void @objc_copyWeak(i8** %[[V8]], i8** %[[V7]])
 
-// CHECK: %[[V9:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK_SOURCE]], i32 0, i32 5
-// CHECK: %[[V10:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK_DEST]], i32 0, i32 5
-// CHECK: %[[BLOCKCOPY_SRC2:.*]] = load i8*, i8** %[[V9]], align 8
-// CHECK: store i8* null, i8** %[[V10]], align 8
-// CHECK: call void @objc_storeStrong(i8** %[[V10]], i8* %[[BLOCKCOPY_SRC2]])
-
-// CHECK: %[[V11:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK_SOURCE]], i32 0, i32 8
-// CHECK: %[[V12:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK_DEST]], i32 0, i32 8
+// CHECK: %[[V11:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK_SOURCE]], i32 0, i32 8
+// CHECK: %[[V12:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK_DEST]], i32 0, i32 8
 // CHECK: invoke void @_ZN5test12S0C1ERKS0_(%[[STRUCT_TEST1_S0]]* %[[V12]], %[[STRUCT_TEST1_S0]]* dereferenceable(4) %[[V11]])
 // CHECK: to label %[[INVOKE_CONT:.*]] unwind label %[[LPAD:.*]]
 
 // CHECK: [[INVOKE_CONT]]:
-// CHECK: %[[V13:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK_SOURCE]], i32 0, i32 9
-// CHECK: %[[V14:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK_DEST]], i32 0, i32 9
+// CHECK: %[[V13:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK_SOURCE]], i32 0, i32 9
+// CHECK: %[[V14:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK_DEST]], i32 0, i32 9
 // CHECK: invoke void @_ZN5test12S0C1ERKS0_(%[[STRUCT_TEST1_S0]]* %[[V14]], %[[STRUCT_TEST1_S0]]* dereferenceable(4) %[[V13]])
 // CHECK: to label %[[INVOKE_CONT4:.*]] unwind label %[[LPAD3:.*]]
 
 // CHECK: [[INVOKE_CONT4]]:
 // CHECK: ret void
 
 // CHECK: [[LPAD]]:
 // CHECK: br label %[[EHCLEANUP:.*]]
 
 // CHECK: [[LPAD3]]:
 // CHECK: invoke void @_ZN5test12S0D1Ev(%[[STRUCT_TEST1_S0]]* %[[V12]])
 // CHECK: to label %[[INVOKE_CONT5:.*]] unwind label %[[TERMINATE_LPAD:.*]]
 
 // CHECK: [[INVOKE_CONT5]]:
 // CHECK: br label %[[EHCLEANUP]]
 
 // CHECK: [[EHCLEANUP]]:
-// CHECK: call void @objc_storeStrong(i8** %[[V10]], i8* null)
 // CHECK: call void @objc_destroyWeak(i8** %[[V8]])
 // CHECK: %[[V21:.*]] = load i8*, i8** %[[V5]], align 8
 // CHECK: call void @_Block_object_dispose(i8* %[[V21]], i32 8)
+// CHECK: call void @objc_storeStrong(i8** %[[V10]], i8* null)
 // CHECK: br label %[[EH_RESUME:.*]]
 
 // CHECK: [[EH_RESUME]]:
 // CHECK: resume { i8*, i32 }
 
 // CHECK: [[TERMINATE_LPAD]]:
 // CHECK: call void @__clang_call_terminate(
 
-// CHECK-O1-LABEL: define internal void @__copy_helper_block_(
+// CHECK-O1-LABEL: define linkonce_odr hidden void @__copy_helper_block_ea8_s_32_b8_40_w_48_c15_ZTSN5test12S0E_56_c15_ZTSN5test12S0E_60(
 // CHECK-O1: tail call void @objc_release({{.*}}) {{.*}} !clang.imprecise_release
+// CHECK-NOEXCP: define linkonce_odr hidden void @__copy_helper_block_8_s_32_b8_40_w_48_c15_ZTSN5test12S0E_56_c15_ZTSN5test12S0E_60(
 
-// CHECK: define internal void @__destroy_helper_block_(
-// CHECK: %[[BLOCK:.*]] = bitcast i8* %{{.*}} to <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>*
-// CHECK: %[[V2:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK]], i32 0, i32 6
-// CHECK: %[[V3:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK]], i32 0, i32 7
-// CHECK: %[[V4:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK]], i32 0, i32 5
-// CHECK: %[[V5:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK]], i32 0, i32 8
-// CHECK: %[[V6:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]] }>* %[[BLOCK]], i32 0, i32 9
+// CHECK: define linkonce_odr hidden void @__destroy_helper_block_ea8_s_32_b8_40_w_48_c15_ZTSN5test12S0E_56_c15_ZTSN5test12S0E_60(
+// CHECK: %[[BLOCK:.*]] = bitcast i8* %{{.*}} to <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>*
+// CHECK: %[[V4:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK]], i32 0, i32 5
+// CHECK: %[[V2:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK]], i32 0, i32 6
+// CHECK: %[[V3:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK]], i32 0, i32 7
+// CHECK: %[[V5:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK]], i32 0, i32 8
+// CHECK: %[[V6:.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>, <{ i8*, i32, i32, i8*, %[[STRUCT_BLOCK_DESCRIPTOR]]*, i8*, i8*, i8*, %[[STRUCT_TEST1_S0]], %[[STRUCT_TEST1_S0]], %[[STRUCT_TRIVIAL_INTERNAL]] }>* %[[BLOCK]], i32 0, i32 9
 // CHECK: invoke void @_ZN5test12S0D1Ev(%[[STRUCT_TEST1_S0]]* %[[V6]])
 // CHECK: to label %[[INVOKE_CONT:.*]] unwind label %[[LPAD:.*]]
 
 // CHECK: [[INVOKE_CONT]]:
 // CHECK: invoke void @_ZN5test12S0D1Ev(%[[STRUCT_TEST1_S0]]* %[[V5]])
 // CHECK: to label %[[INVOKE_CONT2:.*]] unwind label %[[LPAD1:.*]]
 
 // CHECK: [[INVOKE_CONT2]]:
-// CHECK: call void @objc_storeStrong(i8** %[[V4]], i8* null)
 // CHECK: call void @objc_destroyWeak(i8** %[[V3]])
 // CHECK: %[[V7:.*]] = load i8*, i8** %[[V2]], align 8
 // CHECK: call void @_Block_object_dispose(i8* %[[V7]], i32 8)
+// CHECK: call void @objc_storeStrong(i8** %[[V4]], i8* null)
 // CHECK: ret void
 
 // CHECK: [[LPAD]]:
 // CHECK: invoke void @_ZN5test12S0D1Ev(%[[STRUCT_TEST1_S0]]* %[[V5]])
 // CHECK: to label %[[INVOKE_CONT3:.*]] unwind label %[[TERMINATE_LPAD]]
 
 // CHECK: [[LPAD1]]
 // CHECK: br label %[[EHCLEANUP:.*]]
 
 // CHECK: [[INVOKE_CONT3]]:
 // CHECK: br label %[[EHCLEANUP]]
 
 // CHECK: [[EHCLEANUP]]:
-// CHECK: call void @objc_storeStrong(i8** %[[V4]], i8* null)
 // CHECK: call void @objc_destroyWeak(i8** %[[V3]])
 // CHECK: %[[V14:.*]] = load i8*, i8** %[[V2]], align 8
 // CHECK: call void @_Block_object_dispose(i8* %[[V14]], i32 8)
+// CHECK: call void @objc_storeStrong(i8** %[[V4]], i8* null)
 // CHECK: br label %[[EH_RESUME]]
 
 // CHECK: [[EH_RESUME]]:
 // CHECK: resume { i8*, i32 }
 
 // CHECK: [[TERMINATE_LPAD]]:
 // CHECK: call void @__clang_call_terminate(
 
-// CHECK-O1-LABEL: define internal void @__destroy_helper_block_(
+// CHECK-O1-LABEL: define linkonce_odr hidden void @__destroy_helper_block_ea8_s_32_b8_40_w_48_c15_ZTSN5test12S0E_56_c15_ZTSN5test12S0E_60(
 // CHECK-O1: tail call void @objc_release({{.*}}) {{.*}} !clang.imprecise_release
 // CHECK-O1: tail call void @objc_release({{.*}}) {{.*}} !clang.imprecise_release
+// CHECK-NOEXCP: define linkonce_odr hidden void @__destroy_helper_block_8_s_32_b8_40_w_48_c15_ZTSN5test12S0E_56_c15_ZTSN5test12S0E_60(
+
+namespace {
+struct TrivialInternal {
+  int a;
+};
+}
 
 struct S0 {
   S0();
   S0(const S0 &);
   ~S0();
   int f0;
 };
 
 id getObj();
 
 void foo1() {
   __block id t0 = getObj();
   __weak id t1 = getObj();
   id t2 = getObj();
   S0 t3, t4;
-  ^{ (void)t0; (void)t1; (void)t2; (void)t3; (void)t4; };
+  // Capturing a non-external type doesn't cause the copy/dispose helpers to be
+  // internal unless the captured type has a non-trivial copy constructor or
+  // destructor.
+  TrivialInternal t5;
+  ^{ (void)t0; (void)t1; (void)t2; (void)t3; (void)t4; (void)t5; };
 }
 }

test/CodeGenObjCXX/lambda-to-block.mm

 // RUN: %clang_cc1 -x objective-c++ -fblocks -triple x86_64-apple-darwin10 -fobjc-runtime=macosx-fragile-10.5 -std=c++1z -emit-llvm -o - %s | FileCheck %s
 
 // rdar://31385153
 // Shouldn't crash!
 
 void takesBlock(void (^)(void));
 
 struct Copyable {
   Copyable(const Copyable &x);
 };
 
 void hasLambda(Copyable x) {
   takesBlock([x] () { });
 }
-// CHECK-LABEL: define internal void @__copy_helper_block_
+// CHECK-LABEL: define internal void @"__copy_helper_block_
 // CHECK: call void @"_ZZ9hasLambda8CopyableEN3$_0C1ERKS0_"
 // CHECK-LABEL: define internal void @"_ZZ9hasLambda8CopyableEN3$_0C2ERKS0_"
 // CHECK: call void @_ZN8CopyableC1ERKS_

test/CodeGenObjCXX/mrc-weak.mm

 // CHECK-NEXT:  [[T1:%.*]] = bitcast i8* [[T0]] to [[FOO]]*
 // CHECK-NEXT:  [[T2:%.*]] = bitcast [[FOO]]** [[P]] to i8**
 // CHECK-NEXT:  [[T3:%.*]] = bitcast [[FOO]]* [[T1]] to i8*
 // CHECK-NEXT:  call i8* @objc_initWeak(i8** [[T2]], i8* [[T3]])
 // CHECK:       call void @objc_copyWeak
 // CHECK:       call void @use_block
 // CHECK:       call void @objc_destroyWeak
 
-// CHECK-LABEL: define internal void @__copy_helper_block
+// CHECK-LABEL: define linkonce_odr hidden void @__copy_helper_block
 // CHECK:       @objc_copyWeak
 
-// CHECK-LABEL: define internal void @__destroy_helper_block
+// CHECK-LABEL: define linkonce_odr hidden void @__destroy_helper_block
 // CHECK:       @objc_destroyWeak
 
 void test8(void) {
   __block __weak Foo *p = get_object();
   use_block(^{ [p run ]; });
 }
 // CHECK-LABEL: define void @_Z5test8v
 // CHECK:       call i8* @objc_initWeak
 // CHECK-NOT:   call void @objc_copyWeak
 // CHECK:       call void @use_block
 // CHECK:       call void @objc_destroyWeak
 
 // CHECK-LABEL: define internal void @__Block_byref_object_copy
 // CHECK:       call void @objc_moveWeak
 
 // CHECK-LABEL: define internal void @__Block_byref_object_dispose
 // CHECK:       call void @objc_destroyWeak
 
 // CHECK-LABEL: define void @_Z14test9_baselinev()
-// CHECK:       define internal void @__copy_helper
-// CHECK:       define internal void @__destroy_helper
+// CHECK:       define linkonce_odr hidden void @__copy_helper
+// CHECK:       define linkonce_odr hidden void @__destroy_helper
 void test9_baseline(void) {
   Foo *p = get_object();
   use_block(^{ [p run]; });
 }
 
 // CHECK-LABEL: define void @_Z5test9v()
 // CHECK-NOT:   define internal void @__copy_helper
 // CHECK-NOT:   define internal void @__destroy_helper