Add clang support for new Objective-C literal syntax for NSDictionary, NSArray,

NSNumber, and boolean literals.  This includes both Sema and Codegen support.
Included is also support for new Objective-C container subscripting.

My apologies for the large patch.  It was very difficult to break apart.
The patch introduces changes to the driver as well to cause clang to link
in additional runtime support when needed to support the new language features.

Docs are forthcoming to document the implementation and behavior of these features.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@152137 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 505 insertions, 0 deletions

diff --git a/lib/Sema/SemaPseudoObject.cpp b/lib/Sema/SemaPseudoObject.cpp
index d5f1523f62..c51eb3f495 100644
--- a/lib/Sema/SemaPseudoObject.cpp
+++ b/lib/Sema/SemaPseudoObject.cpp
@@ -130,6 +130,28 @@ namespace {
     }
   };
 
+  struct ObjCSubscriptRefRebuilder : Rebuilder<ObjCSubscriptRefRebuilder> {
+    Expr *NewBase;
+    Expr *NewKeyExpr;
+    ObjCSubscriptRefRebuilder(Sema &S, Expr *newBase, Expr *newKeyExpr)
+    : Rebuilder<ObjCSubscriptRefRebuilder>(S), 
+      NewBase(newBase), NewKeyExpr(newKeyExpr) {}
+    
+    typedef ObjCSubscriptRefExpr specific_type;
+    Expr *rebuildSpecific(ObjCSubscriptRefExpr *refExpr) {
+      assert(refExpr->getBaseExpr());
+      assert(refExpr->getKeyExpr());
+      
+      return new (S.Context)
+        ObjCSubscriptRefExpr(NewBase,
+                             NewKeyExpr,
+                             refExpr->getType(), refExpr->getValueKind(),
+                             refExpr->getObjectKind(),refExpr->getAtIndexMethodDecl(),
+                             refExpr->setAtIndexMethodDecl(),
+                             refExpr->getRBracket());
+    }
+  };
+  
   class PseudoOpBuilder {
   public:
     Sema &S;
@@ -215,6 +237,39 @@ namespace {
     ExprResult buildGet();
     ExprResult buildSet(Expr *op, SourceLocation, bool);
   };
+
+ /// A PseudoOpBuilder for Objective-C array/dictionary indexing.
+ class ObjCSubscriptOpBuilder : public PseudoOpBuilder {
+   ObjCSubscriptRefExpr *RefExpr;
+   OpaqueValueExpr *InstanceBase;
+   OpaqueValueExpr *InstanceKey;
+   ObjCMethodDecl *AtIndexGetter;
+   Selector AtIndexGetterSelector;
+  
+   ObjCMethodDecl *AtIndexSetter;
+   Selector AtIndexSetterSelector;
+  
+ public:
+    ObjCSubscriptOpBuilder(Sema &S, ObjCSubscriptRefExpr *refExpr) :
+      PseudoOpBuilder(S, refExpr->getSourceRange().getBegin()), 
+      RefExpr(refExpr),
+    InstanceBase(0), InstanceKey(0), 
+    AtIndexGetter(0), AtIndexSetter(0) { }
+  
+   ExprResult buildRValueOperation(Expr *op);
+   ExprResult buildAssignmentOperation(Scope *Sc,
+                                       SourceLocation opLoc,
+                                       BinaryOperatorKind opcode,
+                                       Expr *LHS, Expr *RHS);
+   Expr *rebuildAndCaptureObject(Expr *syntacticBase);
+   
+   bool findAtIndexGetter();
+   bool findAtIndexSetter();
+  
+   ExprResult buildGet();
+   ExprResult buildSet(Expr *op, SourceLocation, bool);
+ };
+
 }
 
 /// Capture the given expression in an OpaqueValueExpr.
@@ -718,6 +773,438 @@ ObjCPropertyOpBuilder::buildIncDecOperation(Scope *Sc, SourceLocation opcLoc,
   return PseudoOpBuilder::buildIncDecOperation(Sc, opcLoc, opcode, op);
 }
 
+// ObjCSubscript build stuff.
+//
+
+/// objective-c subscripting-specific behavior for doing lvalue-to-rvalue 
+/// conversion.
+/// FIXME. Remove this routine if it is proven that no additional 
+/// specifity is needed.
+ExprResult ObjCSubscriptOpBuilder::buildRValueOperation(Expr *op) {
+  ExprResult result = PseudoOpBuilder::buildRValueOperation(op);
+  if (result.isInvalid()) return ExprError();
+  return result;
+}
+
+/// objective-c subscripting-specific  behavior for doing assignments.
+ExprResult
+ObjCSubscriptOpBuilder::buildAssignmentOperation(Scope *Sc,
+                                                SourceLocation opcLoc,
+                                                BinaryOperatorKind opcode,
+                                                Expr *LHS, Expr *RHS) {
+  assert(BinaryOperator::isAssignmentOp(opcode));
+  // There must be a method to do the Index'ed assignment.
+  if (!findAtIndexSetter())
+    return ExprError();
+  
+  // Verify that we can do a compound assignment.
+  if (opcode != BO_Assign && !findAtIndexGetter())
+    return ExprError();
+  
+  ExprResult result =
+  PseudoOpBuilder::buildAssignmentOperation(Sc, opcLoc, opcode, LHS, RHS);
+  if (result.isInvalid()) return ExprError();
+  
+  // Various warnings about objc Index'ed assignments in ARC.
+  if (S.getLangOptions().ObjCAutoRefCount && InstanceBase) {
+    S.checkRetainCycles(InstanceBase->getSourceExpr(), RHS);
+    S.checkUnsafeExprAssigns(opcLoc, LHS, RHS);
+  }
+  
+  return result;
+}
+
+/// Capture the base object of an Objective-C Index'ed expression.
+Expr *ObjCSubscriptOpBuilder::rebuildAndCaptureObject(Expr *syntacticBase) {
+  assert(InstanceBase == 0);
+  
+  // Capture base expression in an OVE and rebuild the syntactic
+  // form to use the OVE as its base expression.
+  InstanceBase = capture(RefExpr->getBaseExpr());
+  InstanceKey = capture(RefExpr->getKeyExpr());
+    
+  syntacticBase =
+    ObjCSubscriptRefRebuilder(S, InstanceBase, 
+                              InstanceKey).rebuild(syntacticBase);
+  
+  return syntacticBase;
+}
+
+/// CheckSubscriptingKind - This routine decide what type 
+/// of indexing represented by "FromE" is being done.
+Sema::ObjCSubscriptKind 
+  Sema::CheckSubscriptingKind(Expr *FromE) {
+  // If the expression already has integral or enumeration type, we're golden.
+  QualType T = FromE->getType();
+  if (T->isIntegralOrEnumerationType())
+    return OS_Array;
+  
+  // If we don't have a class type in C++, there's no way we can get an
+  // expression of integral or enumeration type.
+  const RecordType *RecordTy = T->getAs<RecordType>();
+  if (!RecordTy)
+    // All other scalar cases are assumed to be dictionary indexing which
+    // caller handles, with diagnostics if needed.
+    return OS_Dictionary;
+  if (!getLangOptions().CPlusPlus || RecordTy->isIncompleteType()) {
+    // No indexing can be done. Issue diagnostics and quit.
+    Diag(FromE->getExprLoc(), diag::err_objc_subscript_type_conversion)
+    << FromE->getType();
+    return OS_Error;
+  }
+  
+  // We must have a complete class type.
+  if (RequireCompleteType(FromE->getExprLoc(), T, 
+                          PDiag(diag::err_objc_index_incomplete_class_type)
+                          << FromE->getSourceRange()))
+    return OS_Error;
+  
+  // Look for a conversion to an integral, enumeration type, or
+  // objective-C pointer type.
+  UnresolvedSet<4> ViableConversions;
+  UnresolvedSet<4> ExplicitConversions;
+  const UnresolvedSetImpl *Conversions
+    = cast<CXXRecordDecl>(RecordTy->getDecl())->getVisibleConversionFunctions();
+  
+  int NoIntegrals=0, NoObjCIdPointers=0;
+  SmallVector<CXXConversionDecl *, 4> ConversionDecls;
+    
+  for (UnresolvedSetImpl::iterator I = Conversions->begin(),
+       E = Conversions->end();
+       I != E;
+       ++I) {
+    if (CXXConversionDecl *Conversion
+        = dyn_cast<CXXConversionDecl>((*I)->getUnderlyingDecl())) {
+      QualType CT = Conversion->getConversionType().getNonReferenceType();
+      if (CT->isIntegralOrEnumerationType()) {
+        ++NoIntegrals;
+        ConversionDecls.push_back(Conversion);
+      }
+      else if (CT->isObjCIdType() ||CT->isBlockPointerType()) {
+        ++NoObjCIdPointers;
+        ConversionDecls.push_back(Conversion);
+      }
+    }
+  }
+  if (NoIntegrals ==1 && NoObjCIdPointers == 0)
+    return OS_Array;
+  if (NoIntegrals == 0 && NoObjCIdPointers == 1)
+    return OS_Dictionary;
+  if (NoIntegrals == 0 && NoObjCIdPointers == 0) {
+    // No conversion function was found. Issue diagnostic and return.
+    Diag(FromE->getExprLoc(), diag::err_objc_subscript_type_conversion)
+      << FromE->getType();
+    return OS_Error;
+  }
+  Diag(FromE->getExprLoc(), diag::err_objc_multiple_subscript_type_conversion)
+      << FromE->getType();
+  for (unsigned int i = 0; i < ConversionDecls.size(); i++)
+    Diag(ConversionDecls[i]->getLocation(), diag::not_conv_function_declared_at);
+    
+  return OS_Error;
+}
+
+bool ObjCSubscriptOpBuilder::findAtIndexGetter() {
+  if (AtIndexGetter)
+    return true;
+  
+  Expr *BaseExpr = RefExpr->getBaseExpr();
+  QualType BaseT = BaseExpr->getType();
+  
+  QualType ResultType;
+  if (const ObjCObjectPointerType *PTy =
+      BaseT->getAs<ObjCObjectPointerType>()) {
+    ResultType = PTy->getPointeeType();
+    if (const ObjCObjectType *iQFaceTy = 
+        ResultType->getAsObjCQualifiedInterfaceType())
+      ResultType = iQFaceTy->getBaseType();
+  }
+  Sema::ObjCSubscriptKind Res = 
+    S.CheckSubscriptingKind(RefExpr->getKeyExpr());
+  if (Res == Sema::OS_Error)
+    return false;
+  bool arrayRef = (Res == Sema::OS_Array);
+  
+  if (ResultType.isNull()) {
+    S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_base_type)
+      << BaseExpr->getType() << arrayRef;
+    return false;
+  }
+  if (!arrayRef) {
+    // dictionary subscripting.
+    // - (id)objectForKeyedSubscript:(id)key;
+    IdentifierInfo *KeyIdents[] = {
+      &S.Context.Idents.get("objectForKeyedSubscript")  
+    };
+    AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
+  }
+  else {
+    // - (id)objectAtIndexedSubscript:(size_t)index;
+    IdentifierInfo *KeyIdents[] = {
+      &S.Context.Idents.get("objectAtIndexedSubscript")  
+    };
+  
+    AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
+  }
+  
+  AtIndexGetter = S.LookupMethodInObjectType(AtIndexGetterSelector, ResultType, 
+                                             true /*instance*/);
+  bool receiverIdType = (BaseT->isObjCIdType() ||
+                         BaseT->isObjCQualifiedIdType());
+  
+  if (!AtIndexGetter && S.getLangOptions().DebuggerObjCLiteral) {
+    AtIndexGetter = ObjCMethodDecl::Create(S.Context, SourceLocation(), 
+                           SourceLocation(), AtIndexGetterSelector,
+                           S.Context.getObjCIdType() /*ReturnType*/,
+                           0 /*TypeSourceInfo */,
+                           S.Context.getTranslationUnitDecl(),
+                           true /*Instance*/, false/*isVariadic*/,
+                           /*isSynthesized=*/false,
+                           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
+                           ObjCMethodDecl::Required,
+                           false);
+    ParmVarDecl *Argument = ParmVarDecl::Create(S.Context, AtIndexGetter,
+                                                SourceLocation(), SourceLocation(),
+                                                arrayRef ? &S.Context.Idents.get("index")
+                                                         : &S.Context.Idents.get("key"),
+                                                arrayRef ? S.Context.UnsignedLongTy
+                                                         : S.Context.getObjCIdType(),
+                                                /*TInfo=*/0,
+                                                SC_None,
+                                                SC_None,
+                                                0);
+    AtIndexGetter->setMethodParams(S.Context, Argument, 
+                                   ArrayRef<SourceLocation>());
+  }
+
+  if (!AtIndexGetter) {
+    if (!receiverIdType) {
+      S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_method_not_found)
+      << BaseExpr->getType() << 0 << arrayRef;
+      return false;
+    }
+    AtIndexGetter = 
+      S.LookupInstanceMethodInGlobalPool(AtIndexGetterSelector, 
+                                         RefExpr->getSourceRange(), 
+                                         true, false);
+  }
+  
+  if (AtIndexGetter) {
+    QualType T = AtIndexGetter->param_begin()[0]->getType();
+    if ((arrayRef && !T->isIntegralOrEnumerationType()) ||
+        (!arrayRef && !T->isObjCObjectPointerType())) {
+      S.Diag(RefExpr->getKeyExpr()->getExprLoc(), 
+             arrayRef ? diag::err_objc_subscript_index_type
+                      : diag::err_objc_subscript_key_type) << T;
+      S.Diag(AtIndexGetter->param_begin()[0]->getLocation(), 
+             diag::note_parameter_type) << T;
+      return false;
+    }
+    QualType R = AtIndexGetter->getResultType();
+    if (!R->isObjCObjectPointerType()) {
+      S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
+             diag::err_objc_indexing_method_result_type) << R << arrayRef;
+      S.Diag(AtIndexGetter->getLocation(), diag::note_method_declared_at) <<
+        AtIndexGetter->getDeclName();
+    }
+  }
+  return true;
+}
+
+bool ObjCSubscriptOpBuilder::findAtIndexSetter() {
+  if (AtIndexSetter)
+    return true;
+  
+  Expr *BaseExpr = RefExpr->getBaseExpr();
+  QualType BaseT = BaseExpr->getType();
+  
+  QualType ResultType;
+  if (const ObjCObjectPointerType *PTy =
+      BaseT->getAs<ObjCObjectPointerType>()) {
+    ResultType = PTy->getPointeeType();
+    if (const ObjCObjectType *iQFaceTy = 
+        ResultType->getAsObjCQualifiedInterfaceType())
+      ResultType = iQFaceTy->getBaseType();
+  }
+  
+  Sema::ObjCSubscriptKind Res = 
+    S.CheckSubscriptingKind(RefExpr->getKeyExpr());
+  if (Res == Sema::OS_Error)
+    return false;
+  bool arrayRef = (Res == Sema::OS_Array);
+  
+  if (ResultType.isNull()) {
+    S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_base_type)
+      << BaseExpr->getType() << arrayRef;
+    return false;
+  }
+  
+  if (!arrayRef) {
+    // dictionary subscripting.
+    // - (void)setObject:(id)object forKeyedSubscript:(id)key;
+    IdentifierInfo *KeyIdents[] = {
+      &S.Context.Idents.get("setObject"),
+      &S.Context.Idents.get("forKeyedSubscript")
+    };
+    AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
+  }
+  else {
+    // - (void)setObject:(id)object atIndexedSubscript:(NSInteger)index;
+    IdentifierInfo *KeyIdents[] = {
+      &S.Context.Idents.get("setObject"),
+      &S.Context.Idents.get("atIndexedSubscript")
+    };
+    AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
+  }
+  AtIndexSetter = S.LookupMethodInObjectType(AtIndexSetterSelector, ResultType, 
+                                             true /*instance*/);
+  
+  bool receiverIdType = (BaseT->isObjCIdType() ||
+                         BaseT->isObjCQualifiedIdType());
+
+  if (!AtIndexSetter && S.getLangOptions().DebuggerObjCLiteral) {
+    TypeSourceInfo *ResultTInfo = 0;
+    QualType ReturnType = S.Context.VoidTy;
+    AtIndexSetter = ObjCMethodDecl::Create(S.Context, SourceLocation(),
+                           SourceLocation(), AtIndexSetterSelector,
+                           ReturnType,
+                           ResultTInfo,
+                           S.Context.getTranslationUnitDecl(),
+                           true /*Instance*/, false/*isVariadic*/,
+                           /*isSynthesized=*/false,
+                           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
+                           ObjCMethodDecl::Required,
+                           false); 
+    SmallVector<ParmVarDecl *, 2> Params;
+    ParmVarDecl *object = ParmVarDecl::Create(S.Context, AtIndexSetter,
+                                                SourceLocation(), SourceLocation(),
+                                                &S.Context.Idents.get("object"),
+                                                S.Context.getObjCIdType(),
+                                                /*TInfo=*/0,
+                                                SC_None,
+                                                SC_None,
+                                                0);
+    Params.push_back(object);
+    ParmVarDecl *key = ParmVarDecl::Create(S.Context, AtIndexSetter,
+                                                SourceLocation(), SourceLocation(),
+                                                arrayRef ?  &S.Context.Idents.get("index")
+                                                         :  &S.Context.Idents.get("key"),
+                                                arrayRef ? S.Context.UnsignedLongTy
+                                                         : S.Context.getObjCIdType(),
+                                                /*TInfo=*/0,
+                                                SC_None,
+                                                SC_None,
+                                                0);
+    Params.push_back(key);
+    AtIndexSetter->setMethodParams(S.Context, Params, ArrayRef<SourceLocation>());
+  }
+  
+  if (!AtIndexSetter) {
+    if (!receiverIdType) {
+      S.Diag(BaseExpr->getExprLoc(), 
+             diag::err_objc_subscript_method_not_found)
+      << BaseExpr->getType() << 1 << arrayRef;
+      return false;
+    }
+    AtIndexSetter = 
+      S.LookupInstanceMethodInGlobalPool(AtIndexSetterSelector, 
+                                         RefExpr->getSourceRange(), 
+                                         true, false);
+  }
+  
+  bool err = false;
+  if (AtIndexSetter && arrayRef) {
+    QualType T = AtIndexSetter->param_begin()[1]->getType();
+    if (!T->isIntegralOrEnumerationType()) {
+      S.Diag(RefExpr->getKeyExpr()->getExprLoc(), 
+             diag::err_objc_subscript_index_type) << T;
+      S.Diag(AtIndexSetter->param_begin()[1]->getLocation(), 
+             diag::note_parameter_type) << T;
+      err = true;
+    }
+    T = AtIndexSetter->param_begin()[0]->getType();
+    if (!T->isObjCObjectPointerType()) {
+      S.Diag(RefExpr->getBaseExpr()->getExprLoc(), 
+             diag::err_objc_subscript_object_type) << T << arrayRef;
+      S.Diag(AtIndexSetter->param_begin()[0]->getLocation(), 
+             diag::note_parameter_type) << T;
+      err = true;
+    }
+  }
+  else if (AtIndexSetter && !arrayRef)
+    for (unsigned i=0; i <2; i++) {
+      QualType T = AtIndexSetter->param_begin()[i]->getType();
+      if (!T->isObjCObjectPointerType()) {
+        if (i == 1)
+          S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
+                 diag::err_objc_subscript_key_type) << T;
+        else
+          S.Diag(RefExpr->getBaseExpr()->getExprLoc(),
+                 diag::err_objc_subscript_dic_object_type) << T;
+        S.Diag(AtIndexSetter->param_begin()[i]->getLocation(), 
+               diag::note_parameter_type) << T;
+        err = true;
+      }
+    }
+
+  return !err;
+}
+
+// Get the object at "Index" position in the container.
+// [BaseExpr objectAtIndexedSubscript : IndexExpr];
+ExprResult ObjCSubscriptOpBuilder::buildGet() {
+  if (!findAtIndexGetter())
+    return ExprError();
+  
+  QualType receiverType = InstanceBase->getType();
+    
+  // Build a message-send.
+  ExprResult msg;
+  Expr *Index = InstanceKey;
+  
+  // Arguments.
+  Expr *args[] = { Index };
+  assert(InstanceBase);
+  msg = S.BuildInstanceMessageImplicit(InstanceBase, receiverType,
+                                       GenericLoc,
+                                       AtIndexGetterSelector, AtIndexGetter,
+                                       MultiExprArg(args, 1));
+  return msg;
+}
+
+/// Store into the container the "op" object at "Index"'ed location
+/// by building this messaging expression:
+/// - (void)setObject:(id)object atIndexedSubscript:(NSInteger)index;
+/// \param bindSetValueAsResult - If true, capture the actual
+///   value being set as the value of the property operation.
+ExprResult ObjCSubscriptOpBuilder::buildSet(Expr *op, SourceLocation opcLoc,
+                                           bool captureSetValueAsResult) {
+  if (!findAtIndexSetter())
+    return ExprError();
+  
+  QualType receiverType = InstanceBase->getType();
+  Expr *Index = InstanceKey;
+  
+  // Arguments.
+  Expr *args[] = { op, Index };
+  
+  // Build a message-send.
+  ExprResult msg = S.BuildInstanceMessageImplicit(InstanceBase, receiverType,
+                                                  GenericLoc,
+                                                  AtIndexSetterSelector,
+                                                  AtIndexSetter,
+                                                  MultiExprArg(args, 2));
+  
+  if (!msg.isInvalid() && captureSetValueAsResult) {
+    ObjCMessageExpr *msgExpr =
+      cast<ObjCMessageExpr>(msg.get()->IgnoreImplicit());
+    Expr *arg = msgExpr->getArg(0);
+    msgExpr->setArg(0, captureValueAsResult(arg));
+  }
+  
+  return msg;
+}
+
 //===----------------------------------------------------------------------===//
 //  General Sema routines.
 //===----------------------------------------------------------------------===//
@@ -728,6 +1215,11 @@ ExprResult Sema::checkPseudoObjectRValue(Expr *E) {
         = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
     ObjCPropertyOpBuilder builder(*this, refExpr);
     return builder.buildRValueOperation(E);
+  }
+  else if (ObjCSubscriptRefExpr *refExpr
+           = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
+    ObjCSubscriptOpBuilder builder(*this, refExpr);
+    return builder.buildRValueOperation(E);
   } else {
     llvm_unreachable("unknown pseudo-object kind!");
   }
@@ -747,6 +1239,9 @@ ExprResult Sema::checkPseudoObjectIncDec(Scope *Sc, SourceLocation opcLoc,
         = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
     ObjCPropertyOpBuilder builder(*this, refExpr);
     return builder.buildIncDecOperation(Sc, opcLoc, opcode, op);
+  } else if (isa<ObjCSubscriptRefExpr>(opaqueRef)) {
+    Diag(opcLoc, diag::err_illegal_container_subscripting_op);
+    return ExprError();
   } else {
     llvm_unreachable("unknown pseudo-object kind!");
   }
@@ -772,6 +1267,10 @@ ExprResult Sema::checkPseudoObjectAssignment(Scope *S, SourceLocation opcLoc,
         = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
     ObjCPropertyOpBuilder builder(*this, refExpr);
     return builder.buildAssignmentOperation(S, opcLoc, opcode, LHS, RHS);
+  } else if (ObjCSubscriptRefExpr *refExpr
+             = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
+    ObjCSubscriptOpBuilder builder(*this, refExpr);
+    return builder.buildAssignmentOperation(S, opcLoc, opcode, LHS, RHS);
   } else {
     llvm_unreachable("unknown pseudo-object kind!");
   }
@@ -786,6 +1285,12 @@ static Expr *stripOpaqueValuesFromPseudoObjectRef(Sema &S, Expr *E) {
         = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
     OpaqueValueExpr *baseOVE = cast<OpaqueValueExpr>(refExpr->getBase());
     return ObjCPropertyRefRebuilder(S, baseOVE->getSourceExpr()).rebuild(E);
+  } else if (ObjCSubscriptRefExpr *refExpr
+               = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
+    OpaqueValueExpr *baseOVE = cast<OpaqueValueExpr>(refExpr->getBaseExpr());
+    OpaqueValueExpr *keyOVE = cast<OpaqueValueExpr>(refExpr->getKeyExpr());
+    return ObjCSubscriptRefRebuilder(S, baseOVE->getSourceExpr(), 
+                                     keyOVE->getSourceExpr()).rebuild(E);
   } else {
     llvm_unreachable("unknown pseudo-object kind!");
   }