Merge branch 'master' of ssh://bitbucket.org/czan/honours

1 files changed, 2663 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
new file mode 100644
index 0000000..9052278
--- /dev/null
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -0,0 +1,2663 @@
+//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements semantic analysis for statements.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Sema/SemaInternal.h"
+#include "clang/Sema/Scope.h"
+#include "clang/Sema/ScopeInfo.h"
+#include "clang/Sema/Initialization.h"
+#include "clang/Sema/Lookup.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/CharUnits.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/ExprObjC.h"
+#include "clang/AST/StmtObjC.h"
+#include "clang/AST/StmtCXX.h"
+#include "clang/AST/TypeLoc.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Basic/TargetInfo.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallVector.h"
+using namespace clang;
+using namespace sema;
+
+StmtResult Sema::ActOnExprStmt(FullExprArg expr) {
+  Expr *E = expr.get();
+  if (!E) // FIXME: FullExprArg has no error state?
+    return StmtError();
+
+  // C99 6.8.3p2: The expression in an expression statement is evaluated as a
+  // void expression for its side effects.  Conversion to void allows any
+  // operand, even incomplete types.
+
+  // Same thing in for stmt first clause (when expr) and third clause.
+  return Owned(static_cast<Stmt*>(E));
+}
+
+
+StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc,
+                               bool HasLeadingEmptyMacro) {
+  return Owned(new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro));
+}
+
+StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc,
+                               SourceLocation EndLoc) {
+  DeclGroupRef DG = dg.getAsVal<DeclGroupRef>();
+
+  // If we have an invalid decl, just return an error.
+  if (DG.isNull()) return StmtError();
+
+  return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc));
+}
+
+void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
+  DeclGroupRef DG = dg.getAsVal<DeclGroupRef>();
+
+  // If we have an invalid decl, just return.
+  if (DG.isNull() || !DG.isSingleDecl()) return;
+  VarDecl *var = cast<VarDecl>(DG.getSingleDecl());
+
+  // suppress any potential 'unused variable' warning.
+  var->setUsed();
+
+  // foreach variables are never actually initialized in the way that
+  // the parser came up with.
+  var->setInit(0);
+
+  // In ARC, we don't need to retain the iteration variable of a fast
+  // enumeration loop.  Rather than actually trying to catch that
+  // during declaration processing, we remove the consequences here.
+  if (getLangOpts().ObjCAutoRefCount) {
+    QualType type = var->getType();
+
+    // Only do this if we inferred the lifetime.  Inferred lifetime
+    // will show up as a local qualifier because explicit lifetime
+    // should have shown up as an AttributedType instead.
+    if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) {
+      // Add 'const' and mark the variable as pseudo-strong.
+      var->setType(type.withConst());
+      var->setARCPseudoStrong(true);
+    }
+  }
+}
+
+/// \brief Diagnose unused '==' and '!=' as likely typos for '=' or '|='.
+///
+/// Adding a cast to void (or other expression wrappers) will prevent the
+/// warning from firing.
+static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) {
+  SourceLocation Loc;
+  bool IsNotEqual, CanAssign;
+
+  if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) {
+    if (Op->getOpcode() != BO_EQ && Op->getOpcode() != BO_NE)
+      return false;
+
+    Loc = Op->getOperatorLoc();
+    IsNotEqual = Op->getOpcode() == BO_NE;
+    CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue();
+  } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) {
+    if (Op->getOperator() != OO_EqualEqual &&
+        Op->getOperator() != OO_ExclaimEqual)
+      return false;
+
+    Loc = Op->getOperatorLoc();
+    IsNotEqual = Op->getOperator() == OO_ExclaimEqual;
+    CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue();
+  } else {
+    // Not a typo-prone comparison.
+    return false;
+  }
+
+  // Suppress warnings when the operator, suspicious as it may be, comes from
+  // a macro expansion.
+  if (Loc.isMacroID())
+    return false;
+
+  S.Diag(Loc, diag::warn_unused_comparison)
+    << (unsigned)IsNotEqual << E->getSourceRange();
+
+  // If the LHS is a plausible entity to assign to, provide a fixit hint to
+  // correct common typos.
+  if (CanAssign) {
+    if (IsNotEqual)
+      S.Diag(Loc, diag::note_inequality_comparison_to_or_assign)
+        << FixItHint::CreateReplacement(Loc, "|=");
+    else
+      S.Diag(Loc, diag::note_equality_comparison_to_assign)
+        << FixItHint::CreateReplacement(Loc, "=");
+  }
+
+  return true;
+}
+
+void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
+  if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S))
+    return DiagnoseUnusedExprResult(Label->getSubStmt());
+
+  const Expr *E = dyn_cast_or_null<Expr>(S);
+  if (!E)
+    return;
+
+  SourceLocation Loc;
+  SourceRange R1, R2;
+  if (SourceMgr.isInSystemMacro(E->getExprLoc()) ||
+      !E->isUnusedResultAWarning(Loc, R1, R2, Context))
+    return;
+
+  // Okay, we have an unused result.  Depending on what the base expression is,
+  // we might want to make a more specific diagnostic.  Check for one of these
+  // cases now.
+  unsigned DiagID = diag::warn_unused_expr;
+  if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E))
+    E = Temps->getSubExpr();
+  if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E))
+    E = TempExpr->getSubExpr();
+
+  if (DiagnoseUnusedComparison(*this, E))
+    return;
+
+  E = E->IgnoreParenImpCasts();
+  if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
+    if (E->getType()->isVoidType())
+      return;
+
+    // If the callee has attribute pure, const, or warn_unused_result, warn with
+    // a more specific message to make it clear what is happening.
+    if (const Decl *FD = CE->getCalleeDecl()) {
+      if (FD->getAttr<WarnUnusedResultAttr>()) {
+        Diag(Loc, diag::warn_unused_result) << R1 << R2;
+        return;
+      }
+      if (FD->getAttr<PureAttr>()) {
+        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure";
+        return;
+      }
+      if (FD->getAttr<ConstAttr>()) {
+        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const";
+        return;
+      }
+    }
+  } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) {
+    if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) {
+      Diag(Loc, diag::err_arc_unused_init_message) << R1;
+      return;
+    }
+    const ObjCMethodDecl *MD = ME->getMethodDecl();
+    if (MD && MD->getAttr<WarnUnusedResultAttr>()) {
+      Diag(Loc, diag::warn_unused_result) << R1 << R2;
+      return;
+    }
+  } else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
+    const Expr *Source = POE->getSyntacticForm();
+    if (isa<ObjCSubscriptRefExpr>(Source))
+      DiagID = diag::warn_unused_container_subscript_expr;
+    else
+      DiagID = diag::warn_unused_property_expr;
+  } else if (const CXXFunctionalCastExpr *FC
+                                       = dyn_cast<CXXFunctionalCastExpr>(E)) {
+    if (isa<CXXConstructExpr>(FC->getSubExpr()) ||
+        isa<CXXTemporaryObjectExpr>(FC->getSubExpr()))
+      return;
+  }
+  // Diagnose "(void*) blah" as a typo for "(void) blah".
+  else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) {
+    TypeSourceInfo *TI = CE->getTypeInfoAsWritten();
+    QualType T = TI->getType();
+
+    // We really do want to use the non-canonical type here.
+    if (T == Context.VoidPtrTy) {
+      PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc());
+
+      Diag(Loc, diag::warn_unused_voidptr)
+        << FixItHint::CreateRemoval(TL.getStarLoc());
+      return;
+    }
+  }
+
+  DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2);
+}
+
+void Sema::ActOnStartOfCompoundStmt() {
+  PushCompoundScope();
+}
+
+void Sema::ActOnFinishOfCompoundStmt() {
+  PopCompoundScope();
+}
+
+sema::CompoundScopeInfo &Sema::getCurCompoundScope() const {
+  return getCurFunction()->CompoundScopes.back();
+}
+
+StmtResult
+Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
+                        MultiStmtArg elts, bool isStmtExpr) {
+  unsigned NumElts = elts.size();
+  Stmt **Elts = reinterpret_cast<Stmt**>(elts.release());
+  // If we're in C89 mode, check that we don't have any decls after stmts.  If
+  // so, emit an extension diagnostic.
+  if (!getLangOpts().C99 && !getLangOpts().CPlusPlus) {
+    // Note that __extension__ can be around a decl.
+    unsigned i = 0;
+    // Skip over all declarations.
+    for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i)
+      /*empty*/;
+
+    // We found the end of the list or a statement.  Scan for another declstmt.
+    for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i)
+      /*empty*/;
+
+    if (i != NumElts) {
+      Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin();
+      Diag(D->getLocation(), diag::ext_mixed_decls_code);
+    }
+  }
+  // Warn about unused expressions in statements.
+  for (unsigned i = 0; i != NumElts; ++i) {
+    // Ignore statements that are last in a statement expression.
+    if (isStmtExpr && i == NumElts - 1)
+      continue;
+
+    DiagnoseUnusedExprResult(Elts[i]);
+  }
+
+  // Check for suspicious empty body (null statement) in `for' and `while'
+  // statements.  Don't do anything for template instantiations, this just adds
+  // noise.
+  if (NumElts != 0 && !CurrentInstantiationScope &&
+      getCurCompoundScope().HasEmptyLoopBodies) {
+    for (unsigned i = 0; i != NumElts - 1; ++i)
+      DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]);
+  }
+
+  return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R));
+}
+
+StmtResult
+Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal,
+                    SourceLocation DotDotDotLoc, Expr *RHSVal,
+                    SourceLocation ColonLoc) {
+  assert((LHSVal != 0) && "missing expression in case statement");
+
+  if (getCurFunction()->SwitchStack.empty()) {
+    Diag(CaseLoc, diag::err_case_not_in_switch);
+    return StmtError();
+  }
+
+  if (!getLangOpts().CPlusPlus0x) {
+    // C99 6.8.4.2p3: The expression shall be an integer constant.
+    // However, GCC allows any evaluatable integer expression.
+    if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent()) {
+      LHSVal = VerifyIntegerConstantExpression(LHSVal).take();
+      if (!LHSVal)
+        return StmtError();
+    }
+
+    // GCC extension: The expression shall be an integer constant.
+
+    if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent()) {
+      RHSVal = VerifyIntegerConstantExpression(RHSVal).take();
+      // Recover from an error by just forgetting about it.
+    }
+  }
+
+  CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc,
+                                        ColonLoc);
+  getCurFunction()->SwitchStack.back()->addSwitchCase(CS);
+  return Owned(CS);
+}
+
+/// ActOnCaseStmtBody - This installs a statement as the body of a case.
+void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) {
+  DiagnoseUnusedExprResult(SubStmt);
+
+  CaseStmt *CS = static_cast<CaseStmt*>(caseStmt);
+  CS->setSubStmt(SubStmt);
+}
+
+StmtResult
+Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
+                       Stmt *SubStmt, Scope *CurScope) {
+  DiagnoseUnusedExprResult(SubStmt);
+
+  if (getCurFunction()->SwitchStack.empty()) {
+    Diag(DefaultLoc, diag::err_default_not_in_switch);
+    return Owned(SubStmt);
+  }
+
+  DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
+  getCurFunction()->SwitchStack.back()->addSwitchCase(DS);
+  return Owned(DS);
+}
+
+StmtResult
+Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
+                     SourceLocation ColonLoc, Stmt *SubStmt) {
+  // If the label was multiply defined, reject it now.
+  if (TheDecl->getStmt()) {
+    Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName();
+    Diag(TheDecl->getLocation(), diag::note_previous_definition);
+    return Owned(SubStmt);
+  }
+
+  // Otherwise, things are good.  Fill in the declaration and return it.
+  LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt);
+  TheDecl->setStmt(LS);
+  if (!TheDecl->isGnuLocal())
+    TheDecl->setLocation(IdentLoc);
+  return Owned(LS);
+}
+
+StmtResult Sema::ActOnAttributedStmt(SourceLocation AttrLoc,
+                                     const AttrVec &Attrs,
+                                     Stmt *SubStmt) {
+  // Fill in the declaration and return it. Variable length will require to
+  // change this to AttributedStmt::Create(Context, ....);
+  // and probably using ArrayRef
+  AttributedStmt *LS = new (Context) AttributedStmt(AttrLoc, Attrs, SubStmt);
+  return Owned(LS);
+}
+
+StmtResult
+Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar,
+                  Stmt *thenStmt, SourceLocation ElseLoc,
+                  Stmt *elseStmt) {
+  ExprResult CondResult(CondVal.release());
+
+  VarDecl *ConditionVar = 0;
+  if (CondVar) {
+    ConditionVar = cast<VarDecl>(CondVar);
+    CondResult = CheckConditionVariable(ConditionVar, IfLoc, true);
+    if (CondResult.isInvalid())
+      return StmtError();
+  }
+  Expr *ConditionExpr = CondResult.takeAs<Expr>();
+  if (!ConditionExpr)
+    return StmtError();
+
+  DiagnoseUnusedExprResult(thenStmt);
+
+  if (!elseStmt) {
+    DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt,
+                          diag::warn_empty_if_body);
+  }
+
+  DiagnoseUnusedExprResult(elseStmt);
+
+  return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr,
+                                    thenStmt, ElseLoc, elseStmt));
+}
+
+/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have
+/// the specified width and sign.  If an overflow occurs, detect it and emit
+/// the specified diagnostic.
+void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val,
+                                              unsigned NewWidth, bool NewSign,
+                                              SourceLocation Loc,
+                                              unsigned DiagID) {
+  // Perform a conversion to the promoted condition type if needed.
+  if (NewWidth > Val.getBitWidth()) {
+    // If this is an extension, just do it.
+    Val = Val.extend(NewWidth);
+    Val.setIsSigned(NewSign);
+
+    // If the input was signed and negative and the output is
+    // unsigned, don't bother to warn: this is implementation-defined
+    // behavior.
+    // FIXME: Introduce a second, default-ignored warning for this case?
+  } else if (NewWidth < Val.getBitWidth()) {
+    // If this is a truncation, check for overflow.
+    llvm::APSInt ConvVal(Val);
+    ConvVal = ConvVal.trunc(NewWidth);
+    ConvVal.setIsSigned(NewSign);
+    ConvVal = ConvVal.extend(Val.getBitWidth());
+    ConvVal.setIsSigned(Val.isSigned());
+    if (ConvVal != Val)
+      Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10);
+
+    // Regardless of whether a diagnostic was emitted, really do the
+    // truncation.
+    Val = Val.trunc(NewWidth);
+    Val.setIsSigned(NewSign);
+  } else if (NewSign != Val.isSigned()) {
+    // Convert the sign to match the sign of the condition.  This can cause
+    // overflow as well: unsigned(INTMIN)
+    // We don't diagnose this overflow, because it is implementation-defined
+    // behavior.
+    // FIXME: Introduce a second, default-ignored warning for this case?
+    llvm::APSInt OldVal(Val);
+    Val.setIsSigned(NewSign);
+  }
+}
+
+namespace {
+  struct CaseCompareFunctor {
+    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
+                    const llvm::APSInt &RHS) {
+      return LHS.first < RHS;
+    }
+    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
+                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
+      return LHS.first < RHS.first;
+    }
+    bool operator()(const llvm::APSInt &LHS,
+                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
+      return LHS < RHS.first;
+    }
+  };
+}
+
+/// CmpCaseVals - Comparison predicate for sorting case values.
+///
+static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
+                        const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
+  if (lhs.first < rhs.first)
+    return true;
+
+  if (lhs.first == rhs.first &&
+      lhs.second->getCaseLoc().getRawEncoding()
+       < rhs.second->getCaseLoc().getRawEncoding())
+    return true;
+  return false;
+}
+
+/// CmpEnumVals - Comparison predicate for sorting enumeration values.
+///
+static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
+                        const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
+{
+  return lhs.first < rhs.first;
+}
+
+/// EqEnumVals - Comparison preficate for uniqing enumeration values.
+///
+static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
+                       const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
+{
+  return lhs.first == rhs.first;
+}
+
+/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
+/// potentially integral-promoted expression @p expr.
+static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) {
+  if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr))
+    expr = cleanups->getSubExpr();
+  while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) {
+    if (impcast->getCastKind() != CK_IntegralCast) break;
+    expr = impcast->getSubExpr();
+  }
+  return expr->getType();
+}
+
+StmtResult
+Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond,
+                             Decl *CondVar) {
+  ExprResult CondResult;
+
+  VarDecl *ConditionVar = 0;
+  if (CondVar) {
+    ConditionVar = cast<VarDecl>(CondVar);
+    CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false);
+    if (CondResult.isInvalid())
+      return StmtError();
+
+    Cond = CondResult.release();
+  }
+
+  if (!Cond)
+    return StmtError();
+
+  CondResult
+    = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond,
+                          PDiag(diag::err_typecheck_statement_requires_integer),
+                                   PDiag(diag::err_switch_incomplete_class_type)
+                                     << Cond->getSourceRange(),
+                                   PDiag(diag::err_switch_explicit_conversion),
+                                         PDiag(diag::note_switch_conversion),
+                                   PDiag(diag::err_switch_multiple_conversions),
+                                         PDiag(diag::note_switch_conversion),
+                                         PDiag(0),
+                                         /*AllowScopedEnumerations*/ true);
+  if (CondResult.isInvalid()) return StmtError();
+  Cond = CondResult.take();
+
+  // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
+  CondResult = UsualUnaryConversions(Cond);
+  if (CondResult.isInvalid()) return StmtError();
+  Cond = CondResult.take();
+
+  if (!CondVar) {
+    CheckImplicitConversions(Cond, SwitchLoc);
+    CondResult = MaybeCreateExprWithCleanups(Cond);
+    if (CondResult.isInvalid())
+      return StmtError();
+    Cond = CondResult.take();
+  }
+
+  getCurFunction()->setHasBranchIntoScope();
+
+  SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond);
+  getCurFunction()->SwitchStack.push_back(SS);
+  return Owned(SS);
+}
+
+static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
+  if (Val.getBitWidth() < BitWidth)
+    Val = Val.extend(BitWidth);
+  else if (Val.getBitWidth() > BitWidth)
+    Val = Val.trunc(BitWidth);
+  Val.setIsSigned(IsSigned);
+}
+
+StmtResult
+Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
+                            Stmt *BodyStmt) {
+  SwitchStmt *SS = cast<SwitchStmt>(Switch);
+  assert(SS == getCurFunction()->SwitchStack.back() &&
+         "switch stack missing push/pop!");
+
+  SS->setBody(BodyStmt, SwitchLoc);
+  getCurFunction()->SwitchStack.pop_back();
+
+  Expr *CondExpr = SS->getCond();
+  if (!CondExpr) return StmtError();
+
+  QualType CondType = CondExpr->getType();
+
+  Expr *CondExprBeforePromotion = CondExpr;
+  QualType CondTypeBeforePromotion =
+      GetTypeBeforeIntegralPromotion(CondExprBeforePromotion);
+
+  // C++ 6.4.2.p2:
+  // Integral promotions are performed (on the switch condition).
+  //
+  // A case value unrepresentable by the original switch condition
+  // type (before the promotion) doesn't make sense, even when it can
+  // be represented by the promoted type.  Therefore we need to find
+  // the pre-promotion type of the switch condition.
+  if (!CondExpr->isTypeDependent()) {
+    // We have already converted the expression to an integral or enumeration
+    // type, when we started the switch statement. If we don't have an
+    // appropriate type now, just return an error.
+    if (!CondType->isIntegralOrEnumerationType())
+      return StmtError();
+
+    if (CondExpr->isKnownToHaveBooleanValue()) {
+      // switch(bool_expr) {...} is often a programmer error, e.g.
+      //   switch(n && mask) { ... }  // Doh - should be "n & mask".
+      // One can always use an if statement instead of switch(bool_expr).
+      Diag(SwitchLoc, diag::warn_bool_switch_condition)
+          << CondExpr->getSourceRange();
+    }
+  }
+
+  // Get the bitwidth of the switched-on value before promotions.  We must
+  // convert the integer case values to this width before comparison.
+  bool HasDependentValue
+    = CondExpr->isTypeDependent() || CondExpr->isValueDependent();
+  unsigned CondWidth
+    = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion);
+  bool CondIsSigned 
+    = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType();
+
+  // Accumulate all of the case values in a vector so that we can sort them
+  // and detect duplicates.  This vector contains the APInt for the case after
+  // it has been converted to the condition type.
+  typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
+  CaseValsTy CaseVals;
+
+  // Keep track of any GNU case ranges we see.  The APSInt is the low value.
+  typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
+  CaseRangesTy CaseRanges;
+
+  DefaultStmt *TheDefaultStmt = 0;
+
+  bool CaseListIsErroneous = false;
+
+  for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
+       SC = SC->getNextSwitchCase()) {
+
+    if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) {
+      if (TheDefaultStmt) {
+        Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
+        Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
+
+        // FIXME: Remove the default statement from the switch block so that
+        // we'll return a valid AST.  This requires recursing down the AST and
+        // finding it, not something we are set up to do right now.  For now,
+        // just lop the entire switch stmt out of the AST.
+        CaseListIsErroneous = true;
+      }
+      TheDefaultStmt = DS;
+
+    } else {
+      CaseStmt *CS = cast<CaseStmt>(SC);
+
+      Expr *Lo = CS->getLHS();
+
+      if (Lo->isTypeDependent() || Lo->isValueDependent()) {
+        HasDependentValue = true;
+        break;
+      }
+
+      llvm::APSInt LoVal;
+
+      if (getLangOpts().CPlusPlus0x) {
+        // C++11 [stmt.switch]p2: the constant-expression shall be a converted
+        // constant expression of the promoted type of the switch condition.
+        ExprResult ConvLo =
+          CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue);
+        if (ConvLo.isInvalid()) {
+          CaseListIsErroneous = true;
+          continue;
+        }
+        Lo = ConvLo.take();
+      } else {
+        // We already verified that the expression has a i-c-e value (C99
+        // 6.8.4.2p3) - get that value now.
+        LoVal = Lo->EvaluateKnownConstInt(Context);
+
+        // If the LHS is not the same type as the condition, insert an implicit
+        // cast.
+        Lo = DefaultLvalueConversion(Lo).take();
+        Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take();
+      }
+
+      // Convert the value to the same width/sign as the condition had prior to
+      // integral promotions.
+      //
+      // FIXME: This causes us to reject valid code:
+      //   switch ((char)c) { case 256: case 0: return 0; }
+      // Here we claim there is a duplicated condition value, but there is not.
+      ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned,
+                                         Lo->getLocStart(),
+                                         diag::warn_case_value_overflow);
+
+      CS->setLHS(Lo);
+
+      // If this is a case range, remember it in CaseRanges, otherwise CaseVals.
+      if (CS->getRHS()) {
+        if (CS->getRHS()->isTypeDependent() ||
+            CS->getRHS()->isValueDependent()) {
+          HasDependentValue = true;
+          break;
+        }
+        CaseRanges.push_back(std::make_pair(LoVal, CS));
+      } else
+        CaseVals.push_back(std::make_pair(LoVal, CS));
+    }
+  }
+
+  if (!HasDependentValue) {
+    // If we don't have a default statement, check whether the
+    // condition is constant.
+    llvm::APSInt ConstantCondValue;
+    bool HasConstantCond = false;
+    if (!HasDependentValue && !TheDefaultStmt) {
+      HasConstantCond
+        = CondExprBeforePromotion->EvaluateAsInt(ConstantCondValue, Context,
+                                                 Expr::SE_AllowSideEffects);
+      assert(!HasConstantCond ||
+             (ConstantCondValue.getBitWidth() == CondWidth &&
+              ConstantCondValue.isSigned() == CondIsSigned));
+    }
+    bool ShouldCheckConstantCond = HasConstantCond;
+
+    // Sort all the scalar case values so we can easily detect duplicates.
+    std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals);
+
+    if (!CaseVals.empty()) {
+      for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) {
+        if (ShouldCheckConstantCond &&
+            CaseVals[i].first == ConstantCondValue)
+          ShouldCheckConstantCond = false;
+
+        if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) {
+          // If we have a duplicate, report it.
+          Diag(CaseVals[i].second->getLHS()->getLocStart(),
+               diag::err_duplicate_case) << CaseVals[i].first.toString(10);
+          Diag(CaseVals[i-1].second->getLHS()->getLocStart(),
+               diag::note_duplicate_case_prev);
+          // FIXME: We really want to remove the bogus case stmt from the
+          // substmt, but we have no way to do this right now.
+          CaseListIsErroneous = true;
+        }
+      }
+    }
+
+    // Detect duplicate case ranges, which usually don't exist at all in
+    // the first place.
+    if (!CaseRanges.empty()) {
+      // Sort all the case ranges by their low value so we can easily detect
+      // overlaps between ranges.
+      std::stable_sort(CaseRanges.begin(), CaseRanges.end());
+
+      // Scan the ranges, computing the high values and removing empty ranges.
+      std::vector<llvm::APSInt> HiVals;
+      for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
+        llvm::APSInt &LoVal = CaseRanges[i].first;
+        CaseStmt *CR = CaseRanges[i].second;
+        Expr *Hi = CR->getRHS();
+        llvm::APSInt HiVal;
+
+        if (getLangOpts().CPlusPlus0x) {
+          // C++11 [stmt.switch]p2: the constant-expression shall be a converted
+          // constant expression of the promoted type of the switch condition.
+          ExprResult ConvHi =
+            CheckConvertedConstantExpression(Hi, CondType, HiVal,
+                                             CCEK_CaseValue);
+          if (ConvHi.isInvalid()) {
+            CaseListIsErroneous = true;
+            continue;
+          }
+          Hi = ConvHi.take();
+        } else {
+          HiVal = Hi->EvaluateKnownConstInt(Context);
+
+          // If the RHS is not the same type as the condition, insert an
+          // implicit cast.
+          Hi = DefaultLvalueConversion(Hi).take();
+          Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take();
+        }
+
+        // Convert the value to the same width/sign as the condition.
+        ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned,
+                                           Hi->getLocStart(),
+                                           diag::warn_case_value_overflow);
+
+        CR->setRHS(Hi);
+
+        // If the low value is bigger than the high value, the case is empty.
+        if (LoVal > HiVal) {
+          Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range)
+            << SourceRange(CR->getLHS()->getLocStart(),
+                           Hi->getLocEnd());
+          CaseRanges.erase(CaseRanges.begin()+i);
+          --i, --e;
+          continue;
+        }
+
+        if (ShouldCheckConstantCond &&
+            LoVal <= ConstantCondValue &&
+            ConstantCondValue <= HiVal)
+          ShouldCheckConstantCond = false;
+
+        HiVals.push_back(HiVal);
+      }
+
+      // Rescan the ranges, looking for overlap with singleton values and other
+      // ranges.  Since the range list is sorted, we only need to compare case
+      // ranges with their neighbors.
+      for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
+        llvm::APSInt &CRLo = CaseRanges[i].first;
+        llvm::APSInt &CRHi = HiVals[i];
+        CaseStmt *CR = CaseRanges[i].second;
+
+        // Check to see whether the case range overlaps with any
+        // singleton cases.
+        CaseStmt *OverlapStmt = 0;
+        llvm::APSInt OverlapVal(32);
+
+        // Find the smallest value >= the lower bound.  If I is in the
+        // case range, then we have overlap.
+        CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(),
+                                                  CaseVals.end(), CRLo,
+                                                  CaseCompareFunctor());
+        if (I != CaseVals.end() && I->first < CRHi) {
+          OverlapVal  = I->first;   // Found overlap with scalar.
+          OverlapStmt = I->second;
+        }
+
+        // Find the smallest value bigger than the upper bound.
+        I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor());
+        if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
+          OverlapVal  = (I-1)->first;      // Found overlap with scalar.
+          OverlapStmt = (I-1)->second;
+        }
+
+        // Check to see if this case stmt overlaps with the subsequent
+        // case range.
+        if (i && CRLo <= HiVals[i-1]) {
+          OverlapVal  = HiVals[i-1];       // Found overlap with range.
+          OverlapStmt = CaseRanges[i-1].second;
+        }
+
+        if (OverlapStmt) {
+          // If we have a duplicate, report it.
+          Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case)
+            << OverlapVal.toString(10);
+          Diag(OverlapStmt->getLHS()->getLocStart(),
+               diag::note_duplicate_case_prev);
+          // FIXME: We really want to remove the bogus case stmt from the
+          // substmt, but we have no way to do this right now.
+          CaseListIsErroneous = true;
+        }
+      }
+    }
+
+    // Complain if we have a constant condition and we didn't find a match.
+    if (!CaseListIsErroneous && ShouldCheckConstantCond) {
+      // TODO: it would be nice if we printed enums as enums, chars as
+      // chars, etc.
+      Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition)
+        << ConstantCondValue.toString(10)
+        << CondExpr->getSourceRange();
+    }
+
+    // Check to see if switch is over an Enum and handles all of its
+    // values.  We only issue a warning if there is not 'default:', but
+    // we still do the analysis to preserve this information in the AST
+    // (which can be used by flow-based analyes).
+    //
+    const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>();
+
+    // If switch has default case, then ignore it.
+    if (!CaseListIsErroneous  && !HasConstantCond && ET) {
+      const EnumDecl *ED = ET->getDecl();
+      typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64>
+        EnumValsTy;
+      EnumValsTy EnumVals;
+
+      // Gather all enum values, set their type and sort them,
+      // allowing easier comparison with CaseVals.
+      for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin();
+           EDI != ED->enumerator_end(); ++EDI) {
+        llvm::APSInt Val = EDI->getInitVal();
+        AdjustAPSInt(Val, CondWidth, CondIsSigned);
+        EnumVals.push_back(std::make_pair(Val, *EDI));
+      }
+      std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals);
+      EnumValsTy::iterator EIend =
+        std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
+
+      // See which case values aren't in enum.
+      EnumValsTy::const_iterator EI = EnumVals.begin();
+      for (CaseValsTy::const_iterator CI = CaseVals.begin();
+           CI != CaseVals.end(); CI++) {
+        while (EI != EIend && EI->first < CI->first)
+          EI++;
+        if (EI == EIend || EI->first > CI->first)
+          Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum)
+            << CondTypeBeforePromotion;
+      }
+      // See which of case ranges aren't in enum
+      EI = EnumVals.begin();
+      for (CaseRangesTy::const_iterator RI = CaseRanges.begin();
+           RI != CaseRanges.end() && EI != EIend; RI++) {
+        while (EI != EIend && EI->first < RI->first)
+          EI++;
+
+        if (EI == EIend || EI->first != RI->first) {
+          Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum)
+            << CondTypeBeforePromotion;
+        }
+
+        llvm::APSInt Hi = 
+          RI->second->getRHS()->EvaluateKnownConstInt(Context);
+        AdjustAPSInt(Hi, CondWidth, CondIsSigned);
+        while (EI != EIend && EI->first < Hi)
+          EI++;
+        if (EI == EIend || EI->first != Hi)
+          Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum)
+            << CondTypeBeforePromotion;
+      }
+
+      // Check which enum vals aren't in switch
+      CaseValsTy::const_iterator CI = CaseVals.begin();
+      CaseRangesTy::const_iterator RI = CaseRanges.begin();
+      bool hasCasesNotInSwitch = false;
+
+      SmallVector<DeclarationName,8> UnhandledNames;
+
+      for (EI = EnumVals.begin(); EI != EIend; EI++){
+        // Drop unneeded case values
+        llvm::APSInt CIVal;
+        while (CI != CaseVals.end() && CI->first < EI->first)
+          CI++;
+
+        if (CI != CaseVals.end() && CI->first == EI->first)
+          continue;
+
+        // Drop unneeded case ranges
+        for (; RI != CaseRanges.end(); RI++) {
+          llvm::APSInt Hi =
+            RI->second->getRHS()->EvaluateKnownConstInt(Context);
+          AdjustAPSInt(Hi, CondWidth, CondIsSigned);
+          if (EI->first <= Hi)
+            break;
+        }
+
+        if (RI == CaseRanges.end() || EI->first < RI->first) {
+          hasCasesNotInSwitch = true;
+          UnhandledNames.push_back(EI->second->getDeclName());
+        }
+      }
+
+      if (TheDefaultStmt && UnhandledNames.empty())
+        Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default);
+
+      // Produce a nice diagnostic if multiple values aren't handled.
+      switch (UnhandledNames.size()) {
+      case 0: break;
+      case 1:
+        Diag(CondExpr->getExprLoc(), TheDefaultStmt 
+          ? diag::warn_def_missing_case1 : diag::warn_missing_case1)
+          << UnhandledNames[0];
+        break;
+      case 2:
+        Diag(CondExpr->getExprLoc(), TheDefaultStmt 
+          ? diag::warn_def_missing_case2 : diag::warn_missing_case2)
+          << UnhandledNames[0] << UnhandledNames[1];
+        break;
+      case 3:
+        Diag(CondExpr->getExprLoc(), TheDefaultStmt
+          ? diag::warn_def_missing_case3 : diag::warn_missing_case3)
+          << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2];
+        break;
+      default:
+        Diag(CondExpr->getExprLoc(), TheDefaultStmt
+          ? diag::warn_def_missing_cases : diag::warn_missing_cases)
+          << (unsigned)UnhandledNames.size()
+          << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2];
+        break;
+      }
+
+      if (!hasCasesNotInSwitch)
+        SS->setAllEnumCasesCovered();
+    }
+  }
+
+  DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), BodyStmt,
+                        diag::warn_empty_switch_body);
+
+  // FIXME: If the case list was broken is some way, we don't have a good system
+  // to patch it up.  Instead, just return the whole substmt as broken.
+  if (CaseListIsErroneous)
+    return StmtError();
+
+  return Owned(SS);
+}
+
+StmtResult
+Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond,
+                     Decl *CondVar, Stmt *Body) {
+  ExprResult CondResult(Cond.release());
+
+  VarDecl *ConditionVar = 0;
+  if (CondVar) {
+    ConditionVar = cast<VarDecl>(CondVar);
+    CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true);
+    if (CondResult.isInvalid())
+      return StmtError();
+  }
+  Expr *ConditionExpr = CondResult.take();
+  if (!ConditionExpr)
+    return StmtError();
+
+  DiagnoseUnusedExprResult(Body);
+
+  if (isa<NullStmt>(Body))
+    getCurCompoundScope().setHasEmptyLoopBodies();
+
+  return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr,
+                                       Body, WhileLoc));
+}
+
+StmtResult
+Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
+                  SourceLocation WhileLoc, SourceLocation CondLParen,
+                  Expr *Cond, SourceLocation CondRParen) {
+  assert(Cond && "ActOnDoStmt(): missing expression");
+
+  ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc);
+  if (CondResult.isInvalid() || CondResult.isInvalid())
+    return StmtError();
+  Cond = CondResult.take();
+
+  CheckImplicitConversions(Cond, DoLoc);
+  CondResult = MaybeCreateExprWithCleanups(Cond);
+  if (CondResult.isInvalid())
+    return StmtError();
+  Cond = CondResult.take();
+
+  DiagnoseUnusedExprResult(Body);
+
+  return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen));
+}
+
+StmtResult
+Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
+                   Stmt *First, FullExprArg second, Decl *secondVar,
+                   FullExprArg third,
+                   SourceLocation RParenLoc, Stmt *Body) {
+  if (!getLangOpts().CPlusPlus) {
+    if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
+      // C99 6.8.5p3: The declaration part of a 'for' statement shall only
+      // declare identifiers for objects having storage class 'auto' or
+      // 'register'.
+      for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end();
+           DI!=DE; ++DI) {
+        VarDecl *VD = dyn_cast<VarDecl>(*DI);
+        if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage())
+          VD = 0;
+        if (VD == 0)
+          Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for);
+        // FIXME: mark decl erroneous!
+      }
+    }
+  }
+
+  ExprResult SecondResult(second.release());
+  VarDecl *ConditionVar = 0;
+  if (secondVar) {
+    ConditionVar = cast<VarDecl>(secondVar);
+    SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true);
+    if (SecondResult.isInvalid())
+      return StmtError();
+  }
+
+  Expr *Third  = third.release().takeAs<Expr>();
+
+  DiagnoseUnusedExprResult(First);
+  DiagnoseUnusedExprResult(Third);
+  DiagnoseUnusedExprResult(Body);
+
+  if (isa<NullStmt>(Body))
+    getCurCompoundScope().setHasEmptyLoopBodies();
+
+  return Owned(new (Context) ForStmt(Context, First,
+                                     SecondResult.take(), ConditionVar,
+                                     Third, Body, ForLoc, LParenLoc,
+                                     RParenLoc));
+}
+
+/// In an Objective C collection iteration statement:
+///   for (x in y)
+/// x can be an arbitrary l-value expression.  Bind it up as a
+/// full-expression.
+StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
+  // Reduce placeholder expressions here.  Note that this rejects the
+  // use of pseudo-object l-values in this position.
+  ExprResult result = CheckPlaceholderExpr(E);
+  if (result.isInvalid()) return StmtError();
+  E = result.take();
+
+  CheckImplicitConversions(E);
+
+  result = MaybeCreateExprWithCleanups(E);
+  if (result.isInvalid()) return StmtError();
+
+  return Owned(static_cast<Stmt*>(result.take()));
+}
+
+ExprResult
+Sema::ActOnObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) {
+  assert(collection);
+
+  // Bail out early if we've got a type-dependent expression.
+  if (collection->isTypeDependent()) return Owned(collection);
+
+  // Perform normal l-value conversion.
+  ExprResult result = DefaultFunctionArrayLvalueConversion(collection);
+  if (result.isInvalid())
+    return ExprError();
+  collection = result.take();
+
+  // The operand needs to have object-pointer type.
+  // TODO: should we do a contextual conversion?
+  const ObjCObjectPointerType *pointerType =
+    collection->getType()->getAs<ObjCObjectPointerType>();
+  if (!pointerType)
+    return Diag(forLoc, diag::err_collection_expr_type)
+             << collection->getType() << collection->getSourceRange();
+
+  // Check that the operand provides
+  //   - countByEnumeratingWithState:objects:count:
+  const ObjCObjectType *objectType = pointerType->getObjectType();
+  ObjCInterfaceDecl *iface = objectType->getInterface();
+
+  // If we have a forward-declared type, we can't do this check.
+  // Under ARC, it is an error not to have a forward-declared class.
+  if (iface && 
+      RequireCompleteType(forLoc, QualType(objectType, 0),
+                          getLangOpts().ObjCAutoRefCount
+                            ? PDiag(diag::err_arc_collection_forward)
+                                << collection->getSourceRange()
+                          : PDiag(0))) {
+    // Otherwise, if we have any useful type information, check that
+    // the type declares the appropriate method.
+  } else if (iface || !objectType->qual_empty()) {
+    IdentifierInfo *selectorIdents[] = {
+      &Context.Idents.get("countByEnumeratingWithState"),
+      &Context.Idents.get("objects"),
+      &Context.Idents.get("count")
+    };
+    Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]);
+
+    ObjCMethodDecl *method = 0;
+
+    // If there's an interface, look in both the public and private APIs.
+    if (iface) {
+      method = iface->lookupInstanceMethod(selector);
+      if (!method) method = LookupPrivateInstanceMethod(selector, iface);
+    }
+
+    // Also check protocol qualifiers.
+    if (!method)
+      method = LookupMethodInQualifiedType(selector, pointerType,
+                                           /*instance*/ true);
+
+    // If we didn't find it anywhere, give up.
+    if (!method) {
+      Diag(forLoc, diag::warn_collection_expr_type)
+        << collection->getType() << selector << collection->getSourceRange();
+    }
+
+    // TODO: check for an incompatible signature?
+  }
+
+  // Wrap up any cleanups in the expression.
+  return Owned(MaybeCreateExprWithCleanups(collection));
+}
+
+StmtResult
+Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
+                                 SourceLocation LParenLoc,
+                                 Stmt *First, Expr *Second,
+                                 SourceLocation RParenLoc, Stmt *Body) {
+  if (First) {
+    QualType FirstType;
+    if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) {
+      if (!DS->isSingleDecl())
+        return StmtError(Diag((*DS->decl_begin())->getLocation(),
+                         diag::err_toomany_element_decls));
+
+      VarDecl *D = cast<VarDecl>(DS->getSingleDecl());
+      FirstType = D->getType();
+      // C99 6.8.5p3: The declaration part of a 'for' statement shall only
+      // declare identifiers for objects having storage class 'auto' or
+      // 'register'.
+      if (!D->hasLocalStorage())
+        return StmtError(Diag(D->getLocation(),
+                              diag::err_non_variable_decl_in_for));
+    } else {
+      Expr *FirstE = cast<Expr>(First);
+      if (!FirstE->isTypeDependent() && !FirstE->isLValue())
+        return StmtError(Diag(First->getLocStart(),
+                   diag::err_selector_element_not_lvalue)
+          << First->getSourceRange());
+
+      FirstType = static_cast<Expr*>(First)->getType();
+    }
+    if (!FirstType->isDependentType() &&
+        !FirstType->isObjCObjectPointerType() &&
+        !FirstType->isBlockPointerType())
+        Diag(ForLoc, diag::err_selector_element_type)
+          << FirstType << First->getSourceRange();
+  }
+
+  return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body,
+                                                   ForLoc, RParenLoc));
+}
+
+namespace {
+
+enum BeginEndFunction {
+  BEF_begin,
+  BEF_end
+};
+
+/// Build a variable declaration for a for-range statement.
+static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc,
+                                     QualType Type, const char *Name) {
+  DeclContext *DC = SemaRef.CurContext;
+  IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name);
+  TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc);
+  VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type,
+                                  TInfo, SC_Auto, SC_None);
+  Decl->setImplicit();
+  return Decl;
+}
+
+/// Finish building a variable declaration for a for-range statement.
+/// \return true if an error occurs.
+static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
+                                  SourceLocation Loc, int diag) {
+  // Deduce the type for the iterator variable now rather than leaving it to
+  // AddInitializerToDecl, so we can produce a more suitable diagnostic.
+  TypeSourceInfo *InitTSI = 0;
+  if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) ||
+      SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI) ==
+          Sema::DAR_Failed)
+    SemaRef.Diag(Loc, diag) << Init->getType();
+  if (!InitTSI) {
+    Decl->setInvalidDecl();
+    return true;
+  }
+  Decl->setTypeSourceInfo(InitTSI);
+  Decl->setType(InitTSI->getType());
+
+  // In ARC, infer lifetime.
+  // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if
+  // we're doing the equivalent of fast iteration.
+  if (SemaRef.getLangOpts().ObjCAutoRefCount && 
+      SemaRef.inferObjCARCLifetime(Decl))
+    Decl->setInvalidDecl();
+
+  SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false,
+                               /*TypeMayContainAuto=*/false);
+  SemaRef.FinalizeDeclaration(Decl);
+  SemaRef.CurContext->addHiddenDecl(Decl);
+  return false;
+}
+
+/// Produce a note indicating which begin/end function was implicitly called
+/// by a C++0x for-range statement. This is often not obvious from the code,
+/// nor from the diagnostics produced when analysing the implicit expressions
+/// required in a for-range statement.
+void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E,
+                                  BeginEndFunction BEF) {
+  CallExpr *CE = dyn_cast<CallExpr>(E);
+  if (!CE)
+    return;
+  FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
+  if (!D)
+    return;
+  SourceLocation Loc = D->getLocation();
+
+  std::string Description;
+  bool IsTemplate = false;
+  if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) {
+    Description = SemaRef.getTemplateArgumentBindingsText(
+      FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs());
+    IsTemplate = true;
+  }
+
+  SemaRef.Diag(Loc, diag::note_for_range_begin_end)
+    << BEF << IsTemplate << Description << E->getType();
+}
+
+/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the
+/// given LookupResult is non-empty, it is assumed to describe a member which
+/// will be invoked. Otherwise, the function will be found via argument
+/// dependent lookup.
+static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S,
+                                            SourceLocation Loc,
+                                            VarDecl *Decl,
+                                            BeginEndFunction BEF,
+                                            const DeclarationNameInfo &NameInfo,
+                                            LookupResult &MemberLookup,
+                                            Expr *Range) {
+  ExprResult CallExpr;
+  if (!MemberLookup.empty()) {
+    ExprResult MemberRef =
+      SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc,
+                                       /*IsPtr=*/false, CXXScopeSpec(),
+                                       /*TemplateKWLoc=*/SourceLocation(),
+                                       /*FirstQualifierInScope=*/0,
+                                       MemberLookup,
+                                       /*TemplateArgs=*/0);
+    if (MemberRef.isInvalid())
+      return ExprError();
+    CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(),
+                                     Loc, 0);
+    if (CallExpr.isInvalid())
+      return ExprError();
+  } else {
+    UnresolvedSet<0> FoundNames;
+    // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace
+    // std is an associated namespace.
+    UnresolvedLookupExpr *Fn =
+      UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0,
+                                   NestedNameSpecifierLoc(), NameInfo,
+                                   /*NeedsADL=*/true, /*Overloaded=*/false,
+                                   FoundNames.begin(), FoundNames.end(),
+                                   /*LookInStdNamespace=*/true);
+    CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc,
+                                               0, /*AllowTypoCorrection=*/false);
+    if (CallExpr.isInvalid()) {
+      SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type)
+        << Range->getType();
+      return ExprError();
+    }
+  }
+  if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc,
+                            diag::err_for_range_iter_deduction_failure)) {
+    NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF);
+    return ExprError();
+  }
+  return CallExpr;
+}
+
+}
+
+/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement.
+///
+/// C++0x [stmt.ranged]:
+///   A range-based for statement is equivalent to
+///
+///   {
+///     auto && __range = range-init;
+///     for ( auto __begin = begin-expr,
+///           __end = end-expr;
+///           __begin != __end;
+///           ++__begin ) {
+///       for-range-declaration = *__begin;
+///       statement
+///     }
+///   }
+///
+/// The body of the loop is not available yet, since it cannot be analysed until
+/// we have determined the type of the for-range-declaration.
+StmtResult
+Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
+                           Stmt *First, SourceLocation ColonLoc, Expr *Range,
+                           SourceLocation RParenLoc) {
+  if (!First || !Range)
+    return StmtError();
+
+  DeclStmt *DS = dyn_cast<DeclStmt>(First);
+  assert(DS && "first part of for range not a decl stmt");
+
+  if (!DS->isSingleDecl()) {
+    Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range);
+    return StmtError();
+  }
+  if (DS->getSingleDecl()->isInvalidDecl())
+    return StmtError();
+
+  if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression))
+    return StmtError();
+
+  // Build  auto && __range = range-init
+  SourceLocation RangeLoc = Range->getLocStart();
+  VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc,
+                                           Context.getAutoRRefDeductType(),
+                                           "__range");
+  if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc,
+                            diag::err_for_range_deduction_failure))
+    return StmtError();
+
+  // Claim the type doesn't contain auto: we've already done the checking.
+  DeclGroupPtrTy RangeGroup =
+    BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false);
+  StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc);
+  if (RangeDecl.isInvalid())
+    return StmtError();
+
+  return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(),
+                              /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS,
+                              RParenLoc);
+}
+
+/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement.
+StmtResult
+Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc,
+                           Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond,
+                           Expr *Inc, Stmt *LoopVarDecl,
+                           SourceLocation RParenLoc) {
+  Scope *S = getCurScope();
+
+  DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl);
+  VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl());
+  QualType RangeVarType = RangeVar->getType();
+
+  DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl);
+  VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl());
+
+  StmtResult BeginEndDecl = BeginEnd;
+  ExprResult NotEqExpr = Cond, IncrExpr = Inc;
+
+  if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) {
+    SourceLocation RangeLoc = RangeVar->getLocation();
+
+    const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType();
+
+    ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
+                                                VK_LValue, ColonLoc);
+    if (BeginRangeRef.isInvalid())
+      return StmtError();
+
+    ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
+                                              VK_LValue, ColonLoc);
+    if (EndRangeRef.isInvalid())
+      return StmtError();
+
+    QualType AutoType = Context.getAutoDeductType();
+    Expr *Range = RangeVar->getInit();
+    if (!Range)
+      return StmtError();
+    QualType RangeType = Range->getType();
+
+    if (RequireCompleteType(RangeLoc, RangeType,
+                            PDiag(diag::err_for_range_incomplete_type)))
+      return StmtError();
+
+    // Build auto __begin = begin-expr, __end = end-expr.
+    VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
+                                             "__begin");
+    VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
+                                           "__end");
+
+    // Build begin-expr and end-expr and attach to __begin and __end variables.
+    ExprResult BeginExpr, EndExpr;
+    if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) {
+      // - if _RangeT is an array type, begin-expr and end-expr are __range and
+      //   __range + __bound, respectively, where __bound is the array bound. If
+      //   _RangeT is an array of unknown size or an array of incomplete type,
+      //   the program is ill-formed;
+
+      // begin-expr is __range.
+      BeginExpr = BeginRangeRef;
+      if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc,
+                                diag::err_for_range_iter_deduction_failure)) {
+        NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
+        return StmtError();
+      }
+
+      // Find the array bound.
+      ExprResult BoundExpr;
+      if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT))
+        BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(),
+                                                 Context.getPointerDiffType(),
+                                                 RangeLoc));
+      else if (const VariableArrayType *VAT =
+               dyn_cast<VariableArrayType>(UnqAT))
+        BoundExpr = VAT->getSizeExpr();
+      else {
+        // Can't be a DependentSizedArrayType or an IncompleteArrayType since
+        // UnqAT is not incomplete and Range is not type-dependent.
+        llvm_unreachable("Unexpected array type in for-range");
+      }
+
+      // end-expr is __range + __bound.
+      EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(),
+                           BoundExpr.get());
+      if (EndExpr.isInvalid())
+        return StmtError();
+      if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc,
+                                diag::err_for_range_iter_deduction_failure)) {
+        NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
+        return StmtError();
+      }
+    } else {
+      DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"),
+                                        ColonLoc);
+      DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"),
+                                      ColonLoc);
+
+      LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName);
+      LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName);
+
+      if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) {
+        // - if _RangeT is a class type, the unqualified-ids begin and end are
+        //   looked up in the scope of class _RangeT as if by class member access
+        //   lookup (3.4.5), and if either (or both) finds at least one
+        //   declaration, begin-expr and end-expr are __range.begin() and
+        //   __range.end(), respectively;
+        LookupQualifiedName(BeginMemberLookup, D);
+        LookupQualifiedName(EndMemberLookup, D);
+
+        if (BeginMemberLookup.empty() != EndMemberLookup.empty()) {
+          Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch)
+            << RangeType << BeginMemberLookup.empty();
+          return StmtError();
+        }
+      } else {
+        // - otherwise, begin-expr and end-expr are begin(__range) and
+        //   end(__range), respectively, where begin and end are looked up with
+        //   argument-dependent lookup (3.4.2). For the purposes of this name
+        //   lookup, namespace std is an associated namespace.
+      }
+
+      BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar,
+                                            BEF_begin, BeginNameInfo,
+                                            BeginMemberLookup,
+                                            BeginRangeRef.get());
+      if (BeginExpr.isInvalid())
+        return StmtError();
+
+      EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar,
+                                          BEF_end, EndNameInfo,
+                                          EndMemberLookup, EndRangeRef.get());
+      if (EndExpr.isInvalid())
+        return StmtError();
+    }
+
+    // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same.
+    QualType BeginType = BeginVar->getType(), EndType = EndVar->getType();
+    if (!Context.hasSameType(BeginType, EndType)) {
+      Diag(RangeLoc, diag::err_for_range_begin_end_types_differ)
+        << BeginType << EndType;
+      NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
+      NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
+    }
+
+    Decl *BeginEndDecls[] = { BeginVar, EndVar };
+    // Claim the type doesn't contain auto: we've already done the checking.
+    DeclGroupPtrTy BeginEndGroup =
+      BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false);
+    BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc);
+
+    const QualType BeginRefNonRefType = BeginType.getNonReferenceType();
+    ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
+                                           VK_LValue, ColonLoc);
+    if (BeginRef.isInvalid())
+      return StmtError();
+
+    ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(),
+                                         VK_LValue, ColonLoc);
+    if (EndRef.isInvalid())
+      return StmtError();
+
+    // Build and check __begin != __end expression.
+    NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal,
+                           BeginRef.get(), EndRef.get());
+    NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get());
+    NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get());
+    if (NotEqExpr.isInvalid()) {
+      NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
+      if (!Context.hasSameType(BeginType, EndType))
+        NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
+      return StmtError();
+    }
+
+    // Build and check ++__begin expression.
+    BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
+                                VK_LValue, ColonLoc);
+    if (BeginRef.isInvalid())
+      return StmtError();
+
+    IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get());
+    IncrExpr = ActOnFinishFullExpr(IncrExpr.get());
+    if (IncrExpr.isInvalid()) {
+      NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
+      return StmtError();
+    }
+
+    // Build and check *__begin  expression.
+    BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
+                                VK_LValue, ColonLoc);
+    if (BeginRef.isInvalid())
+      return StmtError();
+
+    ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get());
+    if (DerefExpr.isInvalid()) {
+      NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
+      return StmtError();
+    }
+
+    // Attach  *__begin  as initializer for VD.
+    if (!LoopVar->isInvalidDecl()) {
+      AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false,
+                           /*TypeMayContainAuto=*/true);
+      if (LoopVar->isInvalidDecl())
+        NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
+    }
+  } else {
+    // The range is implicitly used as a placeholder when it is dependent.
+    RangeVar->setUsed();
+  }
+
+  return Owned(new (Context) CXXForRangeStmt(RangeDS,
+                                     cast_or_null<DeclStmt>(BeginEndDecl.get()),
+                                             NotEqExpr.take(), IncrExpr.take(),
+                                             LoopVarDS, /*Body=*/0, ForLoc,
+                                             ColonLoc, RParenLoc));
+}
+
+/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement.
+/// This is a separate step from ActOnCXXForRangeStmt because analysis of the
+/// body cannot be performed until after the type of the range variable is
+/// determined.
+StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) {
+  if (!S || !B)
+    return StmtError();
+
+  CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S);
+  ForStmt->setBody(B);
+
+  DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B,
+                        diag::warn_empty_range_based_for_body);
+
+  return S;
+}
+
+StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc,
+                               SourceLocation LabelLoc,
+                               LabelDecl *TheDecl) {
+  getCurFunction()->setHasBranchIntoScope();
+  TheDecl->setUsed();
+  return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc));
+}
+
+StmtResult
+Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
+                            Expr *E) {
+  // Convert operand to void*
+  if (!E->isTypeDependent()) {
+    QualType ETy = E->getType();
+    QualType DestTy = Context.getPointerType(Context.VoidTy.withConst());
+    ExprResult ExprRes = Owned(E);
+    AssignConvertType ConvTy =
+      CheckSingleAssignmentConstraints(DestTy, ExprRes);
+    if (ExprRes.isInvalid())
+      return StmtError();
+    E = ExprRes.take();
+    if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing))
+      return StmtError();
+    E = MaybeCreateExprWithCleanups(E);
+  }
+
+  getCurFunction()->setHasIndirectGoto();
+
+  return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E));
+}
+
+StmtResult
+Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
+  Scope *S = CurScope->getContinueParent();
+  if (!S) {
+    // C99 6.8.6.2p1: A break shall appear only in or as a loop body.
+    return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop));
+  }
+
+  return Owned(new (Context) ContinueStmt(ContinueLoc));
+}
+
+StmtResult
+Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
+  Scope *S = CurScope->getBreakParent();
+  if (!S) {
+    // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
+    return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch));
+  }
+
+  return Owned(new (Context) BreakStmt(BreakLoc));
+}
+
+/// \brief Determine whether the given expression is a candidate for
+/// copy elision in either a return statement or a throw expression.
+///
+/// \param ReturnType If we're determining the copy elision candidate for
+/// a return statement, this is the return type of the function. If we're
+/// determining the copy elision candidate for a throw expression, this will
+/// be a NULL type.
+///
+/// \param E The expression being returned from the function or block, or
+/// being thrown.
+///
+/// \param AllowFunctionParameter Whether we allow function parameters to
+/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but
+/// we re-use this logic to determine whether we should try to move as part of
+/// a return or throw (which does allow function parameters).
+///
+/// \returns The NRVO candidate variable, if the return statement may use the
+/// NRVO, or NULL if there is no such candidate.
+const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType,
+                                             Expr *E,
+                                             bool AllowFunctionParameter) {
+  QualType ExprType = E->getType();
+  // - in a return statement in a function with ...
+  // ... a class return type ...
+  if (!ReturnType.isNull()) {
+    if (!ReturnType->isRecordType())
+      return 0;
+    // ... the same cv-unqualified type as the function return type ...
+    if (!Context.hasSameUnqualifiedType(ReturnType, ExprType))
+      return 0;
+  }
+
+  // ... the expression is the name of a non-volatile automatic object
+  // (other than a function or catch-clause parameter)) ...
+  const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens());
+  if (!DR)
+    return 0;
+  const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl());
+  if (!VD)
+    return 0;
+
+  // ...object (other than a function or catch-clause parameter)...
+  if (VD->getKind() != Decl::Var &&
+      !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar))
+    return 0;
+  if (VD->isExceptionVariable()) return 0;
+
+  // ...automatic...
+  if (!VD->hasLocalStorage()) return 0;
+
+  // ...non-volatile...
+  if (VD->getType().isVolatileQualified()) return 0;
+  if (VD->getType()->isReferenceType()) return 0;
+
+  // __block variables can't be allocated in a way that permits NRVO.
+  if (VD->hasAttr<BlocksAttr>()) return 0;
+
+  // Variables with higher required alignment than their type's ABI
+  // alignment cannot use NRVO.
+  if (VD->hasAttr<AlignedAttr>() &&
+      Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType()))
+    return 0;
+
+  return VD;
+}
+
+/// \brief Perform the initialization of a potentially-movable value, which
+/// is the result of return value.
+///
+/// This routine implements C++0x [class.copy]p33, which attempts to treat
+/// returned lvalues as rvalues in certain cases (to prefer move construction),
+/// then falls back to treating them as lvalues if that failed.
+ExprResult
+Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
+                                      const VarDecl *NRVOCandidate,
+                                      QualType ResultType,
+                                      Expr *Value,
+                                      bool AllowNRVO) {
+  // C++0x [class.copy]p33:
+  //   When the criteria for elision of a copy operation are met or would
+  //   be met save for the fact that the source object is a function
+  //   parameter, and the object to be copied is designated by an lvalue,
+  //   overload resolution to select the constructor for the copy is first
+  //   performed as if the object were designated by an rvalue.
+  ExprResult Res = ExprError();
+  if (AllowNRVO &&
+      (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) {
+    ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack,
+                              Value->getType(), CK_LValueToRValue,
+                              Value, VK_XValue);
+
+    Expr *InitExpr = &AsRvalue;
+    InitializationKind Kind
+      = InitializationKind::CreateCopy(Value->getLocStart(),
+                                       Value->getLocStart());
+    InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1);
+
+    //   [...] If overload resolution fails, or if the type of the first
+    //   parameter of the selected constructor is not an rvalue reference
+    //   to the object's type (possibly cv-qualified), overload resolution
+    //   is performed again, considering the object as an lvalue.
+    if (Seq) {
+      for (InitializationSequence::step_iterator Step = Seq.step_begin(),
+           StepEnd = Seq.step_end();
+           Step != StepEnd; ++Step) {
+        if (Step->Kind != InitializationSequence::SK_ConstructorInitialization)
+          continue;
+
+        CXXConstructorDecl *Constructor
+        = cast<CXXConstructorDecl>(Step->Function.Function);
+
+        const RValueReferenceType *RRefType
+          = Constructor->getParamDecl(0)->getType()
+                                                 ->getAs<RValueReferenceType>();
+
+        // If we don't meet the criteria, break out now.
+        if (!RRefType ||
+            !Context.hasSameUnqualifiedType(RRefType->getPointeeType(),
+                            Context.getTypeDeclType(Constructor->getParent())))
+          break;
+
+        // Promote "AsRvalue" to the heap, since we now need this
+        // expression node to persist.
+        Value = ImplicitCastExpr::Create(Context, Value->getType(),
+                                         CK_LValueToRValue, Value, 0,
+                                         VK_XValue);
+
+        // Complete type-checking the initialization of the return type
+        // using the constructor we found.
+        Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1));
+      }
+    }
+  }
+
+  // Either we didn't meet the criteria for treating an lvalue as an rvalue,
+  // above, or overload resolution failed. Either way, we need to try
+  // (again) now with the return value expression as written.
+  if (Res.isInvalid())
+    Res = PerformCopyInitialization(Entity, SourceLocation(), Value);
+
+  return Res;
+}
+
+/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements
+/// for capturing scopes.
+///
+StmtResult
+Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
+  // If this is the first return we've seen, infer the return type.
+  // [expr.prim.lambda]p4 in C++11; block literals follow a superset of those
+  // rules which allows multiple return statements.
+  CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction());
+  if (CurCap->HasImplicitReturnType) {
+    QualType ReturnT;
+    if (RetValExp && !isa<InitListExpr>(RetValExp)) {
+      ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp);
+      if (Result.isInvalid())
+        return StmtError();
+      RetValExp = Result.take();
+
+      if (!RetValExp->isTypeDependent())
+        ReturnT = RetValExp->getType();
+      else
+        ReturnT = Context.DependentTy;
+    } else { 
+      if (RetValExp) {
+        // C++11 [expr.lambda.prim]p4 bans inferring the result from an
+        // initializer list, because it is not an expression (even
+        // though we represent it as one). We still deduce 'void'.
+        Diag(ReturnLoc, diag::err_lambda_return_init_list)
+          << RetValExp->getSourceRange();
+      }
+
+      ReturnT = Context.VoidTy;
+    }
+    // We require the return types to strictly match here.
+    if (!CurCap->ReturnType.isNull() &&
+        !CurCap->ReturnType->isDependentType() &&
+        !ReturnT->isDependentType() &&
+        !Context.hasSameType(ReturnT, CurCap->ReturnType)) { 
+      Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible) 
+          << ReturnT << CurCap->ReturnType
+          << (getCurLambda() != 0);
+      return StmtError();
+    }
+    CurCap->ReturnType = ReturnT;
+  }
+  QualType FnRetType = CurCap->ReturnType;
+  assert(!FnRetType.isNull());
+
+  if (BlockScopeInfo *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) {
+    if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) {
+      Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr);
+      return StmtError();
+    }
+  } else {
+    LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(CurCap);
+    if (LSI->CallOperator->getType()->getAs<FunctionType>()->getNoReturnAttr()){
+      Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr);
+      return StmtError();
+    }
+  }
+
+  // Otherwise, verify that this result type matches the previous one.  We are
+  // pickier with blocks than for normal functions because we don't have GCC
+  // compatibility to worry about here.
+  const VarDecl *NRVOCandidate = 0;
+  if (FnRetType->isDependentType()) {
+    // Delay processing for now.  TODO: there are lots of dependent
+    // types we can conclusively prove aren't void.
+  } else if (FnRetType->isVoidType()) {
+    if (RetValExp && !isa<InitListExpr>(RetValExp) &&
+        !(getLangOpts().CPlusPlus &&
+          (RetValExp->isTypeDependent() ||
+           RetValExp->getType()->isVoidType()))) {
+      if (!getLangOpts().CPlusPlus &&
+          RetValExp->getType()->isVoidType())
+        Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2;
+      else {
+        Diag(ReturnLoc, diag::err_return_block_has_expr);
+        RetValExp = 0;
+      }
+    }
+  } else if (!RetValExp) {
+    return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr));
+  } else if (!RetValExp->isTypeDependent()) {
+    // we have a non-void block with an expression, continue checking
+
+    // C99 6.8.6.4p3(136): The return statement is not an assignment. The
+    // overlap restriction of subclause 6.5.16.1 does not apply to the case of
+    // function return.
+
+    // In C++ the return statement is handled via a copy initialization.
+    // the C version of which boils down to CheckSingleAssignmentConstraints.
+    NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
+    InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc,
+                                                                   FnRetType,
+                                                          NRVOCandidate != 0);
+    ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate,
+                                                     FnRetType, RetValExp);
+    if (Res.isInvalid()) {
+      // FIXME: Cleanup temporaries here, anyway?
+      return StmtError();
+    }
+    RetValExp = Res.take();
+    CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
+  }
+
+  if (RetValExp) {
+    CheckImplicitConversions(RetValExp, ReturnLoc);
+    RetValExp = MaybeCreateExprWithCleanups(RetValExp);
+  }
+  ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp,
+                                                NRVOCandidate);
+
+  // If we need to check for the named return value optimization, save the
+  // return statement in our scope for later processing.
+  if (getLangOpts().CPlusPlus && FnRetType->isRecordType() && 
+      !CurContext->isDependentContext())
+    FunctionScopes.back()->Returns.push_back(Result);
+
+  return Owned(Result);
+}
+
+StmtResult
+Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
+  // Check for unexpanded parameter packs.
+  if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp))
+    return StmtError();
+  
+  if (isa<CapturingScopeInfo>(getCurFunction()))
+    return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp);
+
+  QualType FnRetType;
+  QualType RelatedRetType;
+  if (const FunctionDecl *FD = getCurFunctionDecl()) {
+    FnRetType = FD->getResultType();
+    if (FD->hasAttr<NoReturnAttr>() ||
+        FD->getType()->getAs<FunctionType>()->getNoReturnAttr())
+      Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr)
+        << FD->getDeclName();
+  } else if (ObjCMethodDecl *MD = getCurMethodDecl()) {
+    FnRetType = MD->getResultType();
+    if (MD->hasRelatedResultType() && MD->getClassInterface()) {
+      // In the implementation of a method with a related return type, the
+      // type used to type-check the validity of return statements within the 
+      // method body is a pointer to the type of the class being implemented.
+      RelatedRetType = Context.getObjCInterfaceType(MD->getClassInterface());
+      RelatedRetType = Context.getObjCObjectPointerType(RelatedRetType);
+    }
+  } else // If we don't have a function/method context, bail.
+    return StmtError();
+
+  ReturnStmt *Result = 0;
+  if (FnRetType->isVoidType()) {
+    if (RetValExp) {
+      if (isa<InitListExpr>(RetValExp)) {
+        // We simply never allow init lists as the return value of void
+        // functions. This is compatible because this was never allowed before,
+        // so there's no legacy code to deal with.
+        NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
+        int FunctionKind = 0;
+        if (isa<ObjCMethodDecl>(CurDecl))
+          FunctionKind = 1;
+        else if (isa<CXXConstructorDecl>(CurDecl))
+          FunctionKind = 2;
+        else if (isa<CXXDestructorDecl>(CurDecl))
+          FunctionKind = 3;
+
+        Diag(ReturnLoc, diag::err_return_init_list)
+          << CurDecl->getDeclName() << FunctionKind
+          << RetValExp->getSourceRange();
+
+        // Drop the expression.
+        RetValExp = 0;
+      } else if (!RetValExp->isTypeDependent()) {
+        // C99 6.8.6.4p1 (ext_ since GCC warns)
+        unsigned D = diag::ext_return_has_expr;
+        if (RetValExp->getType()->isVoidType())
+          D = diag::ext_return_has_void_expr;
+        else {
+          ExprResult Result = Owned(RetValExp);
+          Result = IgnoredValueConversions(Result.take());
+          if (Result.isInvalid())
+            return StmtError();
+          RetValExp = Result.take();
+          RetValExp = ImpCastExprToType(RetValExp,
+                                        Context.VoidTy, CK_ToVoid).take();
+        }
+
+        // return (some void expression); is legal in C++.
+        if (D != diag::ext_return_has_void_expr ||
+            !getLangOpts().CPlusPlus) {
+          NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
+
+          int FunctionKind = 0;
+          if (isa<ObjCMethodDecl>(CurDecl))
+            FunctionKind = 1;
+          else if (isa<CXXConstructorDecl>(CurDecl))
+            FunctionKind = 2;
+          else if (isa<CXXDestructorDecl>(CurDecl))
+            FunctionKind = 3;
+
+          Diag(ReturnLoc, D)
+            << CurDecl->getDeclName() << FunctionKind
+            << RetValExp->getSourceRange();
+        }
+      }
+
+      if (RetValExp) {
+        CheckImplicitConversions(RetValExp, ReturnLoc);
+        RetValExp = MaybeCreateExprWithCleanups(RetValExp);
+      }
+    }
+
+    Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0);
+  } else if (!RetValExp && !FnRetType->isDependentType()) {
+    unsigned DiagID = diag::warn_return_missing_expr;  // C90 6.6.6.4p4
+    // C99 6.8.6.4p1 (ext_ since GCC warns)
+    if (getLangOpts().C99) DiagID = diag::ext_return_missing_expr;
+
+    if (FunctionDecl *FD = getCurFunctionDecl())
+      Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/;
+    else
+      Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/;
+    Result = new (Context) ReturnStmt(ReturnLoc);
+  } else {
+    const VarDecl *NRVOCandidate = 0;
+    if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) {
+      // we have a non-void function with an expression, continue checking
+
+      if (!RelatedRetType.isNull()) {
+        // If we have a related result type, perform an extra conversion here.
+        // FIXME: The diagnostics here don't really describe what is happening.
+        InitializedEntity Entity =
+            InitializedEntity::InitializeTemporary(RelatedRetType);
+        
+        ExprResult Res = PerformCopyInitialization(Entity, SourceLocation(),
+                                                   RetValExp);
+        if (Res.isInvalid()) {
+          // FIXME: Cleanup temporaries here, anyway?
+          return StmtError();
+        }
+        RetValExp = Res.takeAs<Expr>();
+      }
+
+      // C99 6.8.6.4p3(136): The return statement is not an assignment. The
+      // overlap restriction of subclause 6.5.16.1 does not apply to the case of
+      // function return.
+
+      // In C++ the return statement is handled via a copy initialization,
+      // the C version of which boils down to CheckSingleAssignmentConstraints.
+      NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
+      InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc,
+                                                                     FnRetType,
+                                                            NRVOCandidate != 0);
+      ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate,
+                                                       FnRetType, RetValExp);
+      if (Res.isInvalid()) {
+        // FIXME: Cleanup temporaries here, anyway?
+        return StmtError();
+      }
+
+      RetValExp = Res.takeAs<Expr>();
+      if (RetValExp)
+        CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
+    }
+
+    if (RetValExp) {
+      CheckImplicitConversions(RetValExp, ReturnLoc);
+      RetValExp = MaybeCreateExprWithCleanups(RetValExp);
+    }
+    Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate);
+  }
+
+  // If we need to check for the named return value optimization, save the
+  // return statement in our scope for later processing.
+  if (getLangOpts().CPlusPlus && FnRetType->isRecordType() &&
+      !CurContext->isDependentContext())
+    FunctionScopes.back()->Returns.push_back(Result);
+  
+  return Owned(Result);
+}
+
+/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently
+/// ignore "noop" casts in places where an lvalue is required by an inline asm.
+/// We emulate this behavior when -fheinous-gnu-extensions is specified, but
+/// provide a strong guidance to not use it.
+///
+/// This method checks to see if the argument is an acceptable l-value and
+/// returns false if it is a case we can handle.
+static bool CheckAsmLValue(const Expr *E, Sema &S) {
+  // Type dependent expressions will be checked during instantiation.
+  if (E->isTypeDependent())
+    return false;
+
+  if (E->isLValue())
+    return false;  // Cool, this is an lvalue.
+
+  // Okay, this is not an lvalue, but perhaps it is the result of a cast that we
+  // are supposed to allow.
+  const Expr *E2 = E->IgnoreParenNoopCasts(S.Context);
+  if (E != E2 && E2->isLValue()) {
+    if (!S.getLangOpts().HeinousExtensions)
+      S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue)
+        << E->getSourceRange();
+    else
+      S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue)
+        << E->getSourceRange();
+    // Accept, even if we emitted an error diagnostic.
+    return false;
+  }
+
+  // None of the above, just randomly invalid non-lvalue.
+  return true;
+}
+
+/// isOperandMentioned - Return true if the specified operand # is mentioned
+/// anywhere in the decomposed asm string.
+static bool isOperandMentioned(unsigned OpNo, 
+                         ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) {
+  for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) {
+    const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p];
+    if (!Piece.isOperand()) continue;
+    
+    // If this is a reference to the input and if the input was the smaller
+    // one, then we have to reject this asm.
+    if (Piece.getOperandNo() == OpNo)
+      return true;
+  }
+ 
+  return false;
+}
+
+StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple,
+                              bool IsVolatile, unsigned NumOutputs,
+                              unsigned NumInputs, IdentifierInfo **Names,
+                              MultiExprArg constraints, MultiExprArg exprs,
+                              Expr *asmString, MultiExprArg clobbers,
+                              SourceLocation RParenLoc, bool MSAsm) {
+  unsigned NumClobbers = clobbers.size();
+  StringLiteral **Constraints =
+    reinterpret_cast<StringLiteral**>(constraints.get());
+  Expr **Exprs = exprs.get();
+  StringLiteral *AsmString = cast<StringLiteral>(asmString);
+  StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get());
+
+  SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
+
+  // The parser verifies that there is a string literal here.
+  if (!AsmString->isAscii())
+    return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character)
+      << AsmString->getSourceRange());
+
+  for (unsigned i = 0; i != NumOutputs; i++) {
+    StringLiteral *Literal = Constraints[i];
+    if (!Literal->isAscii())
+      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
+        << Literal->getSourceRange());
+
+    StringRef OutputName;
+    if (Names[i])
+      OutputName = Names[i]->getName();
+
+    TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName);
+    if (!Context.getTargetInfo().validateOutputConstraint(Info))
+      return StmtError(Diag(Literal->getLocStart(),
+                            diag::err_asm_invalid_output_constraint)
+                       << Info.getConstraintStr());
+
+    // Check that the output exprs are valid lvalues.
+    Expr *OutputExpr = Exprs[i];
+    if (CheckAsmLValue(OutputExpr, *this)) {
+      return StmtError(Diag(OutputExpr->getLocStart(),
+                  diag::err_asm_invalid_lvalue_in_output)
+        << OutputExpr->getSourceRange());
+    }
+
+    OutputConstraintInfos.push_back(Info);
+  }
+
+  SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
+
+  for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
+    StringLiteral *Literal = Constraints[i];
+    if (!Literal->isAscii())
+      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
+        << Literal->getSourceRange());
+
+    StringRef InputName;
+    if (Names[i])
+      InputName = Names[i]->getName();
+
+    TargetInfo::ConstraintInfo Info(Literal->getString(), InputName);
+    if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(),
+                                                NumOutputs, Info)) {
+      return StmtError(Diag(Literal->getLocStart(),
+                            diag::err_asm_invalid_input_constraint)
+                       << Info.getConstraintStr());
+    }
+
+    Expr *InputExpr = Exprs[i];
+
+    // Only allow void types for memory constraints.
+    if (Info.allowsMemory() && !Info.allowsRegister()) {
+      if (CheckAsmLValue(InputExpr, *this))
+        return StmtError(Diag(InputExpr->getLocStart(),
+                              diag::err_asm_invalid_lvalue_in_input)
+                         << Info.getConstraintStr()
+                         << InputExpr->getSourceRange());
+    }
+
+    if (Info.allowsRegister()) {
+      if (InputExpr->getType()->isVoidType()) {
+        return StmtError(Diag(InputExpr->getLocStart(),
+                              diag::err_asm_invalid_type_in_input)
+          << InputExpr->getType() << Info.getConstraintStr()
+          << InputExpr->getSourceRange());
+      }
+    }
+
+    ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]);
+    if (Result.isInvalid())
+      return StmtError();
+
+    Exprs[i] = Result.take();
+    InputConstraintInfos.push_back(Info);
+  }
+
+  // Check that the clobbers are valid.
+  for (unsigned i = 0; i != NumClobbers; i++) {
+    StringLiteral *Literal = Clobbers[i];
+    if (!Literal->isAscii())
+      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
+        << Literal->getSourceRange());
+
+    StringRef Clobber = Literal->getString();
+
+    if (!Context.getTargetInfo().isValidClobber(Clobber))
+      return StmtError(Diag(Literal->getLocStart(),
+                  diag::err_asm_unknown_register_name) << Clobber);
+  }
+
+  AsmStmt *NS =
+    new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm,
+                          NumOutputs, NumInputs, Names, Constraints, Exprs,
+                          AsmString, NumClobbers, Clobbers, RParenLoc);
+  // Validate the asm string, ensuring it makes sense given the operands we
+  // have.
+  SmallVector<AsmStmt::AsmStringPiece, 8> Pieces;
+  unsigned DiagOffs;
+  if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
+    Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID)
+           << AsmString->getSourceRange();
+    return StmtError();
+  }
+
+  // Validate tied input operands for type mismatches.
+  for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
+    TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
+
+    // If this is a tied constraint, verify that the output and input have
+    // either exactly the same type, or that they are int/ptr operands with the
+    // same size (int/long, int*/long, are ok etc).
+    if (!Info.hasTiedOperand()) continue;
+
+    unsigned TiedTo = Info.getTiedOperand();
+    unsigned InputOpNo = i+NumOutputs;
+    Expr *OutputExpr = Exprs[TiedTo];
+    Expr *InputExpr = Exprs[InputOpNo];
+
+    if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent())
+      continue;
+
+    QualType InTy = InputExpr->getType();
+    QualType OutTy = OutputExpr->getType();
+    if (Context.hasSameType(InTy, OutTy))
+      continue;  // All types can be tied to themselves.
+
+    // Decide if the input and output are in the same domain (integer/ptr or
+    // floating point.
+    enum AsmDomain {
+      AD_Int, AD_FP, AD_Other
+    } InputDomain, OutputDomain;
+
+    if (InTy->isIntegerType() || InTy->isPointerType())
+      InputDomain = AD_Int;
+    else if (InTy->isRealFloatingType())
+      InputDomain = AD_FP;
+    else
+      InputDomain = AD_Other;
+
+    if (OutTy->isIntegerType() || OutTy->isPointerType())
+      OutputDomain = AD_Int;
+    else if (OutTy->isRealFloatingType())
+      OutputDomain = AD_FP;
+    else
+      OutputDomain = AD_Other;
+
+    // They are ok if they are the same size and in the same domain.  This
+    // allows tying things like:
+    //   void* to int*
+    //   void* to int            if they are the same size.
+    //   double to long double   if they are the same size.
+    //
+    uint64_t OutSize = Context.getTypeSize(OutTy);
+    uint64_t InSize = Context.getTypeSize(InTy);
+    if (OutSize == InSize && InputDomain == OutputDomain &&
+        InputDomain != AD_Other)
+      continue;
+
+    // If the smaller input/output operand is not mentioned in the asm string,
+    // then we can promote the smaller one to a larger input and the asm string
+    // won't notice.
+    bool SmallerValueMentioned = false;
+    
+    // If this is a reference to the input and if the input was the smaller
+    // one, then we have to reject this asm.
+    if (isOperandMentioned(InputOpNo, Pieces)) {
+      // This is a use in the asm string of the smaller operand.  Since we
+      // codegen this by promoting to a wider value, the asm will get printed
+      // "wrong".
+      SmallerValueMentioned |= InSize < OutSize;
+    }
+    if (isOperandMentioned(TiedTo, Pieces)) {
+      // If this is a reference to the output, and if the output is the larger
+      // value, then it's ok because we'll promote the input to the larger type.
+      SmallerValueMentioned |= OutSize < InSize;
+    }
+
+    // If the smaller value wasn't mentioned in the asm string, and if the
+    // output was a register, just extend the shorter one to the size of the
+    // larger one.
+    if (!SmallerValueMentioned && InputDomain != AD_Other &&
+        OutputConstraintInfos[TiedTo].allowsRegister())
+      continue;
+    
+    // Either both of the operands were mentioned or the smaller one was
+    // mentioned.  One more special case that we'll allow: if the tied input is
+    // integer, unmentioned, and is a constant, then we'll allow truncating it
+    // down to the size of the destination.
+    if (InputDomain == AD_Int && OutputDomain == AD_Int &&
+        !isOperandMentioned(InputOpNo, Pieces) &&
+        InputExpr->isEvaluatable(Context)) {
+      CastKind castKind =
+        (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast);
+      InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take();
+      Exprs[InputOpNo] = InputExpr;
+      NS->setInputExpr(i, InputExpr);
+      continue;
+    }
+    
+    Diag(InputExpr->getLocStart(),
+         diag::err_asm_tying_incompatible_types)
+      << InTy << OutTy << OutputExpr->getSourceRange()
+      << InputExpr->getSourceRange();
+    return StmtError();
+  }
+
+  return Owned(NS);
+}
+
+StmtResult
+Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
+                           SourceLocation RParen, Decl *Parm,
+                           Stmt *Body) {
+  VarDecl *Var = cast_or_null<VarDecl>(Parm);
+  if (Var && Var->isInvalidDecl())
+    return StmtError();
+
+  return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body));
+}
+
+StmtResult
+Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) {
+  return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body));
+}
+
+StmtResult
+Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
+                         MultiStmtArg CatchStmts, Stmt *Finally) {
+  if (!getLangOpts().ObjCExceptions)
+    Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try";
+
+  getCurFunction()->setHasBranchProtectedScope();
+  unsigned NumCatchStmts = CatchStmts.size();
+  return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try,
+                                     CatchStmts.release(),
+                                     NumCatchStmts,
+                                     Finally));
+}
+
+StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc,
+                                                  Expr *Throw) {
+  if (Throw) {
+    Throw = MaybeCreateExprWithCleanups(Throw);
+    ExprResult Result = DefaultLvalueConversion(Throw);
+    if (Result.isInvalid())
+      return StmtError();
+
+    Throw = Result.take();
+    QualType ThrowType = Throw->getType();
+    // Make sure the expression type is an ObjC pointer or "void *".
+    if (!ThrowType->isDependentType() &&
+        !ThrowType->isObjCObjectPointerType()) {
+      const PointerType *PT = ThrowType->getAs<PointerType>();
+      if (!PT || !PT->getPointeeType()->isVoidType())
+        return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object)
+                         << Throw->getType() << Throw->getSourceRange());
+    }
+  }
+
+  return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw));
+}
+
+StmtResult
+Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
+                           Scope *CurScope) {
+  if (!getLangOpts().ObjCExceptions)
+    Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw";
+
+  if (!Throw) {
+    // @throw without an expression designates a rethrow (which much occur
+    // in the context of an @catch clause).
+    Scope *AtCatchParent = CurScope;
+    while (AtCatchParent && !AtCatchParent->isAtCatchScope())
+      AtCatchParent = AtCatchParent->getParent();
+    if (!AtCatchParent)
+      return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch));
+  }
+  
+  return BuildObjCAtThrowStmt(AtLoc, Throw);
+}
+
+ExprResult
+Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) {
+  ExprResult result = DefaultLvalueConversion(operand);
+  if (result.isInvalid())
+    return ExprError();
+  operand = result.take();
+
+  // Make sure the expression type is an ObjC pointer or "void *".
+  QualType type = operand->getType();
+  if (!type->isDependentType() &&
+      !type->isObjCObjectPointerType()) {
+    const PointerType *pointerType = type->getAs<PointerType>();
+    if (!pointerType || !pointerType->getPointeeType()->isVoidType())
+      return Diag(atLoc, diag::error_objc_synchronized_expects_object)
+               << type << operand->getSourceRange();
+  }
+
+  // The operand to @synchronized is a full-expression.
+  return MaybeCreateExprWithCleanups(operand);
+}
+
+StmtResult
+Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr,
+                                  Stmt *SyncBody) {
+  // We can't jump into or indirect-jump out of a @synchronized block.
+  getCurFunction()->setHasBranchProtectedScope();
+  return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody));
+}
+
+/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
+/// and creates a proper catch handler from them.
+StmtResult
+Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
+                         Stmt *HandlerBlock) {
+  // There's nothing to test that ActOnExceptionDecl didn't already test.
+  return Owned(new (Context) CXXCatchStmt(CatchLoc,
+                                          cast_or_null<VarDecl>(ExDecl),
+                                          HandlerBlock));
+}
+
+StmtResult
+Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) {
+  getCurFunction()->setHasBranchProtectedScope();
+  return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body));
+}
+
+namespace {
+
+class TypeWithHandler {
+  QualType t;
+  CXXCatchStmt *stmt;
+public:
+  TypeWithHandler(const QualType &type, CXXCatchStmt *statement)
+  : t(type), stmt(statement) {}
+
+  // An arbitrary order is fine as long as it places identical
+  // types next to each other.
+  bool operator<(const TypeWithHandler &y) const {
+    if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr())
+      return true;
+    if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr())
+      return false;
+    else
+      return getTypeSpecStartLoc() < y.getTypeSpecStartLoc();
+  }
+
+  bool operator==(const TypeWithHandler& other) const {
+    return t == other.t;
+  }
+
+  CXXCatchStmt *getCatchStmt() const { return stmt; }
+  SourceLocation getTypeSpecStartLoc() const {
+    return stmt->getExceptionDecl()->getTypeSpecStartLoc();
+  }
+};
+
+}
+
+/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
+/// handlers and creates a try statement from them.
+StmtResult
+Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
+                       MultiStmtArg RawHandlers) {
+  // Don't report an error if 'try' is used in system headers.
+  if (!getLangOpts().CXXExceptions &&
+      !getSourceManager().isInSystemHeader(TryLoc))
+      Diag(TryLoc, diag::err_exceptions_disabled) << "try";
+
+  unsigned NumHandlers = RawHandlers.size();
+  assert(NumHandlers > 0 &&
+         "The parser shouldn't call this if there are no handlers.");
+  Stmt **Handlers = RawHandlers.get();
+
+  SmallVector<TypeWithHandler, 8> TypesWithHandlers;
+
+  for (unsigned i = 0; i < NumHandlers; ++i) {
+    CXXCatchStmt *Handler = cast<CXXCatchStmt>(Handlers[i]);
+    if (!Handler->getExceptionDecl()) {
+      if (i < NumHandlers - 1)
+        return StmtError(Diag(Handler->getLocStart(),
+                              diag::err_early_catch_all));
+
+      continue;
+    }
+
+    const QualType CaughtType = Handler->getCaughtType();
+    const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType);
+    TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler));
+  }
+
+  // Detect handlers for the same type as an earlier one.
+  if (NumHandlers > 1) {
+    llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end());
+
+    TypeWithHandler prev = TypesWithHandlers[0];
+    for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) {
+      TypeWithHandler curr = TypesWithHandlers[i];
+
+      if (curr == prev) {
+        Diag(curr.getTypeSpecStartLoc(),
+             diag::warn_exception_caught_by_earlier_handler)
+          << curr.getCatchStmt()->getCaughtType().getAsString();
+        Diag(prev.getTypeSpecStartLoc(),
+             diag::note_previous_exception_handler)
+          << prev.getCatchStmt()->getCaughtType().getAsString();
+      }
+
+      prev = curr;
+    }
+  }
+
+  getCurFunction()->setHasBranchProtectedScope();
+
+  // FIXME: We should detect handlers that cannot catch anything because an
+  // earlier handler catches a superclass. Need to find a method that is not
+  // quadratic for this.
+  // Neither of these are explicitly forbidden, but every compiler detects them
+  // and warns.
+
+  return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock,
+                                  Handlers, NumHandlers));
+}
+
+StmtResult
+Sema::ActOnSEHTryBlock(bool IsCXXTry,
+                       SourceLocation TryLoc,
+                       Stmt *TryBlock,
+                       Stmt *Handler) {
+  assert(TryBlock && Handler);
+
+  getCurFunction()->setHasBranchProtectedScope();
+
+  return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler));
+}
+
+StmtResult
+Sema::ActOnSEHExceptBlock(SourceLocation Loc,
+                          Expr *FilterExpr,
+                          Stmt *Block) {
+  assert(FilterExpr && Block);
+
+  if(!FilterExpr->getType()->isIntegerType()) {
+    return StmtError(Diag(FilterExpr->getExprLoc(),
+                     diag::err_filter_expression_integral)
+                     << FilterExpr->getType());
+  }
+
+  return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block));
+}
+
+StmtResult
+Sema::ActOnSEHFinallyBlock(SourceLocation Loc,
+                           Stmt *Block) {
+  assert(Block);
+  return Owned(SEHFinallyStmt::Create(Context,Loc,Block));
+}
+
+StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
+                                            bool IsIfExists,
+                                            NestedNameSpecifierLoc QualifierLoc,
+                                            DeclarationNameInfo NameInfo,
+                                            Stmt *Nested)
+{
+  return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists,
+                                             QualifierLoc, NameInfo, 
+                                             cast<CompoundStmt>(Nested));
+}
+
+
+StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc, 
+                                            bool IsIfExists,
+                                            CXXScopeSpec &SS, 
+                                            UnqualifiedId &Name,
+                                            Stmt *Nested) {
+  return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists, 
+                                    SS.getWithLocInContext(Context),
+                                    GetNameFromUnqualifiedId(Name),
+                                    Nested);
+}