/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/Sema/SemaStmt.cpp

Bug Summary

File:	clang/lib/Sema/SemaStmt.cpp
Warning:	line 2455, column 8 Called C++ object pointer is null
Annotated Source Code

Press '?' to see keyboard shortcuts
Show analyzer invocation
clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name SemaStmt.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -relaxed-aliasing -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/Sema -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include -D NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/tools/clang/lib/Sema -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2021-09-04-040900-46481-1 -x c++ /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/clang/lib/Sema/SemaStmt.cpp
1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9//  This file implements semantic analysis for statements.
10//
11//===----------------------------------------------------------------------===//

13#include "clang/AST/ASTContext.h"
14#include "clang/AST/ASTDiagnostic.h"
15#include "clang/AST/ASTLambda.h"
16#include "clang/AST/CXXInheritance.h"
17#include "clang/AST/CharUnits.h"
18#include "clang/AST/DeclObjC.h"
19#include "clang/AST/EvaluatedExprVisitor.h"
20#include "clang/AST/ExprCXX.h"
21#include "clang/AST/ExprObjC.h"
22#include "clang/AST/IgnoreExpr.h"
23#include "clang/AST/RecursiveASTVisitor.h"
24#include "clang/AST/StmtCXX.h"
25#include "clang/AST/StmtObjC.h"
26#include "clang/AST/TypeLoc.h"
27#include "clang/AST/TypeOrdering.h"
28#include "clang/Basic/TargetInfo.h"
29#include "clang/Lex/Preprocessor.h"
30#include "clang/Sema/Initialization.h"
31#include "clang/Sema/Lookup.h"
32#include "clang/Sema/Ownership.h"
33#include "clang/Sema/Scope.h"
34#include "clang/Sema/ScopeInfo.h"
35#include "clang/Sema/SemaInternal.h"
36#include "llvm/ADT/ArrayRef.h"
37#include "llvm/ADT/DenseMap.h"
38#include "llvm/ADT/STLExtras.h"
39#include "llvm/ADT/SmallPtrSet.h"
40#include "llvm/ADT/SmallString.h"
41#include "llvm/ADT/SmallVector.h"

43using namespace clang;
44using namespace sema;

46StmtResult Sema::ActOnExprStmt(ExprResult FE, bool DiscardedValue) {
if (FE.isInvalid())
  return StmtError();

FE = ActOnFinishFullExpr(FE.get(), FE.get()->getExprLoc(), DiscardedValue);
if (FE.isInvalid())
  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 StmtResult(FE.getAs<Stmt>());
60}


63StmtResult Sema::ActOnExprStmtError() {
DiscardCleanupsInEvaluationContext();
return StmtError();
66}

68StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc,
                             bool HasLeadingEmptyMacro) {
return new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro);
71}

73StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc,
                             SourceLocation EndLoc) {
DeclGroupRef DG = dg.get();

// If we have an invalid decl, just return an error.
if (DG.isNull()) return StmtError();

return new (Context) DeclStmt(DG, StartLoc, EndLoc);
81}

83void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
DeclGroupRef DG = dg.get();

// If we don't have a declaration, or we have an invalid declaration,
// just return.
if (DG.isNull() || !DG.isSingleDecl())
  return;

Decl *decl = DG.getSingleDecl();
if (!decl || decl->isInvalidDecl())
  return;

// Only variable declarations are permitted.
VarDecl *var = dyn_cast<VarDecl>(decl);
if (!var) {
  Diag(decl->getLocation(), diag::err_non_variable_decl_in_for);
  decl->setInvalidDecl();
  return;
}

// foreach variables are never actually initialized in the way that
// the parser came up with.
var->setInit(nullptr);

// 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);
  }
}
122}

124/// Diagnose unused comparisons, both builtin and overloaded operators.
125/// For '==' and '!=', suggest fixits for '=' or '|='.
126///
127/// Adding a cast to void (or other expression wrappers) will prevent the
128/// warning from firing.
129static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) {
SourceLocation Loc;
bool CanAssign;
enum { Equality, Inequality, Relational, ThreeWay } Kind;

if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) {
  if (!Op->isComparisonOp())
    return false;

  if (Op->getOpcode() == BO_EQ)
    Kind = Equality;
  else if (Op->getOpcode() == BO_NE)
    Kind = Inequality;
  else if (Op->getOpcode() == BO_Cmp)
    Kind = ThreeWay;
  else {
    assert(Op->isRelationalOp())(static_cast<void> (0));
    Kind = Relational;
  }
  Loc = Op->getOperatorLoc();
  CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue();
} else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) {
  switch (Op->getOperator()) {
  case OO_EqualEqual:
    Kind = Equality;
    break;
  case OO_ExclaimEqual:
    Kind = Inequality;
    break;
  case OO_Less:
  case OO_Greater:
  case OO_GreaterEqual:
  case OO_LessEqual:
    Kind = Relational;
    break;
  case OO_Spaceship:
    Kind = ThreeWay;
    break;
  default:
    return false;
  }

  Loc = Op->getOperatorLoc();
  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 (S.SourceMgr.isMacroBodyExpansion(Loc))
  return false;

S.Diag(Loc, diag::warn_unused_comparison)
  << (unsigned)Kind << E->getSourceRange();

// If the LHS is a plausible entity to assign to, provide a fixit hint to
// correct common typos.
if (CanAssign) {
  if (Kind == Inequality)
    S.Diag(Loc, diag::note_inequality_comparison_to_or_assign)
      << FixItHint::CreateReplacement(Loc, "|=");
  else if (Kind == Equality)
    S.Diag(Loc, diag::note_equality_comparison_to_assign)
      << FixItHint::CreateReplacement(Loc, "=");
}

return true;
198}

200static bool DiagnoseNoDiscard(Sema &S, const WarnUnusedResultAttr *A,
                            SourceLocation Loc, SourceRange R1,
                            SourceRange R2, bool IsCtor) {
if (!A)
  return false;
StringRef Msg = A->getMessage();

if (Msg.empty()) {
  if (IsCtor)
    return S.Diag(Loc, diag::warn_unused_constructor) << A << R1 << R2;
  return S.Diag(Loc, diag::warn_unused_result) << A << R1 << R2;
}

if (IsCtor)
  return S.Diag(Loc, diag::warn_unused_constructor_msg) << A << Msg << R1
                                                        << R2;
return S.Diag(Loc, diag::warn_unused_result_msg) << A << Msg << R1 << R2;
217}

219void 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;

// If we are in an unevaluated expression context, then there can be no unused
// results because the results aren't expected to be used in the first place.
if (isUnevaluatedContext())
  return;

SourceLocation ExprLoc = E->IgnoreParenImpCasts()->getExprLoc();
// In most cases, we don't want to warn if the expression is written in a
// macro body, or if the macro comes from a system header. If the offending
// expression is a call to a function with the warn_unused_result attribute,
// we warn no matter the location. Because of the order in which the various
// checks need to happen, we factor out the macro-related test here.
bool ShouldSuppress =
    SourceMgr.isMacroBodyExpansion(ExprLoc) ||
    SourceMgr.isInSystemMacro(ExprLoc);

const Expr *WarnExpr;
SourceLocation Loc;
SourceRange R1, R2;
if (!E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Context))
  return;

// If this is a GNU statement expression expanded from a macro, it is probably
// unused because it is a function-like macro that can be used as either an
// expression or statement.  Don't warn, because it is almost certainly a
// false positive.
if (isa<StmtExpr>(E) && Loc.isMacroID())
  return;

// Check if this is the UNREFERENCED_PARAMETER from the Microsoft headers.
// That macro is frequently used to suppress "unused parameter" warnings,
// but its implementation makes clang's -Wunused-value fire.  Prevent this.
if (isa<ParenExpr>(E->IgnoreImpCasts()) && Loc.isMacroID()) {
  SourceLocation SpellLoc = Loc;
  if (findMacroSpelling(SpellLoc, "UNREFERENCED_PARAMETER"))
    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 FullExpr *Temps = dyn_cast<FullExpr>(E))
  E = Temps->getSubExpr();
if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E))
  E = TempExpr->getSubExpr();

if (DiagnoseUnusedComparison(*this, E))
  return;

E = WarnExpr;
if (const auto *Cast = dyn_cast<CastExpr>(E))
  if (Cast->getCastKind() == CK_NoOp ||
      Cast->getCastKind() == CK_ConstructorConversion)
    E = Cast->getSubExpr()->IgnoreImpCasts();

if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
  if (E->getType()->isVoidType())
    return;

  if (DiagnoseNoDiscard(*this, cast_or_null<WarnUnusedResultAttr>(
                                   CE->getUnusedResultAttr(Context)),
                        Loc, R1, R2, /*isCtor=*/false))
    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 the call
  // is written in a macro body, only warn if it has the warn_unused_result
  // attribute.
  if (const Decl *FD = CE->getCalleeDecl()) {
    if (ShouldSuppress)
      return;
    if (FD->hasAttr<PureAttr>()) {
      Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure";
      return;
    }
    if (FD->hasAttr<ConstAttr>()) {
      Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const";
      return;
    }
  }
} else if (const auto *CE = dyn_cast<CXXConstructExpr>(E)) {
  if (const CXXConstructorDecl *Ctor = CE->getConstructor()) {
    const auto *A = Ctor->getAttr<WarnUnusedResultAttr>();
    A = A ? A : Ctor->getParent()->getAttr<WarnUnusedResultAttr>();
    if (DiagnoseNoDiscard(*this, A, Loc, R1, R2, /*isCtor=*/true))
      return;
  }
} else if (const auto *ILE = dyn_cast<InitListExpr>(E)) {
  if (const TagDecl *TD = ILE->getType()->getAsTagDecl()) {

    if (DiagnoseNoDiscard(*this, TD->getAttr<WarnUnusedResultAttr>(), Loc, R1,
                          R2, /*isCtor=*/false))
      return;
  }
} else if (ShouldSuppress)
  return;

E = WarnExpr;
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) {
    if (DiagnoseNoDiscard(*this, MD->getAttr<WarnUnusedResultAttr>(), Loc, R1,
                          R2, /*isCtor=*/false))
      return;
  }
} else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
  const Expr *Source = POE->getSyntacticForm();
  // Handle the actually selected call of an OpenMP specialized call.
  if (LangOpts.OpenMP && isa<CallExpr>(Source) &&
      POE->getNumSemanticExprs() == 1 &&
      isa<CallExpr>(POE->getSemanticExpr(0)))
    return DiagnoseUnusedExprResult(POE->getSemanticExpr(0));
  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)) {
  const Expr *E = FC->getSubExpr();
  if (const CXXBindTemporaryExpr *TE = dyn_cast<CXXBindTemporaryExpr>(E))
    E = TE->getSubExpr();
  if (isa<CXXTemporaryObjectExpr>(E))
    return;
  if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(E))
    if (const CXXRecordDecl *RD = CE->getType()->getAsCXXRecordDecl())
      if (!RD->getAttr<WarnUnusedAttr>())
        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 = TI->getTypeLoc().castAs<PointerTypeLoc>();

    Diag(Loc, diag::warn_unused_voidptr)
      << FixItHint::CreateRemoval(TL.getStarLoc());
    return;
  }
}

// Tell the user to assign it into a variable to force a volatile load if this
// isn't an array.
if (E->isGLValue() && E->getType().isVolatileQualified() &&
    !E->getType()->isArrayType()) {
  Diag(Loc, diag::warn_unused_volatile) << R1 << R2;
  return;
}

DiagRuntimeBehavior(Loc, nullptr, PDiag(DiagID) << R1 << R2);
383}

385void Sema::ActOnStartOfCompoundStmt(bool IsStmtExpr) {
PushCompoundScope(IsStmtExpr);
387}

389void Sema::ActOnAfterCompoundStatementLeadingPragmas() {
if (getCurFPFeatures().isFPConstrained()) {
  FunctionScopeInfo *FSI = getCurFunction();
  assert(FSI)(static_cast<void> (0));
  FSI->setUsesFPIntrin();
}
395}

397void Sema::ActOnFinishOfCompoundStmt() {
PopCompoundScope();
399}

401sema::CompoundScopeInfo &Sema::getCurCompoundScope() const {
return getCurFunction()->CompoundScopes.back();
403}

405StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
                                 ArrayRef<Stmt *> Elts, bool isStmtExpr) {
const unsigned NumElts = Elts.size();

// 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);
  }
}

// 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 CompoundStmt::Create(Context, Elts, L, R);
438}

440ExprResult
441Sema::ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val) {
if (!Val.get())
  return Val;

if (DiagnoseUnexpandedParameterPack(Val.get()))
  return ExprError();

// If we're not inside a switch, let the 'case' statement handling diagnose
// this. Just clean up after the expression as best we can.
if (getCurFunction()->SwitchStack.empty())
  return ActOnFinishFullExpr(Val.get(), Val.get()->getExprLoc(), false,
                             getLangOpts().CPlusPlus11);

Expr *CondExpr =
    getCurFunction()->SwitchStack.back().getPointer()->getCond();
if (!CondExpr)
  return ExprError();
QualType CondType = CondExpr->getType();

auto CheckAndFinish = [&](Expr *E) {
  if (CondType->isDependentType() || E->isTypeDependent())
    return ExprResult(E);

  if (getLangOpts().CPlusPlus11) {
    // C++11 [stmt.switch]p2: the constant-expression shall be a converted
    // constant expression of the promoted type of the switch condition.
    llvm::APSInt TempVal;
    return CheckConvertedConstantExpression(E, CondType, TempVal,
                                            CCEK_CaseValue);
  }

  ExprResult ER = E;
  if (!E->isValueDependent())
    ER = VerifyIntegerConstantExpression(E, AllowFold);
  if (!ER.isInvalid())
    ER = DefaultLvalueConversion(ER.get());
  if (!ER.isInvalid())
    ER = ImpCastExprToType(ER.get(), CondType, CK_IntegralCast);
  if (!ER.isInvalid())
    ER = ActOnFinishFullExpr(ER.get(), ER.get()->getExprLoc(), false);
  return ER;
};

ExprResult Converted = CorrectDelayedTyposInExpr(
    Val, /*InitDecl=*/nullptr, /*RecoverUncorrectedTypos=*/false,
    CheckAndFinish);
if (Converted.get() == Val.get())
  Converted = CheckAndFinish(Val.get());
return Converted;
490}

492StmtResult
493Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHSVal,
                  SourceLocation DotDotDotLoc, ExprResult RHSVal,
                  SourceLocation ColonLoc) {
assert((LHSVal.isInvalid() || LHSVal.get()) && "missing LHS value")(static_cast<void> (0));
assert((DotDotDotLoc.isInvalid() ? RHSVal.isUnset()(static_cast<void> (0))
                                 : RHSVal.isInvalid() || RHSVal.get()) &&(static_cast<void> (0))
       "missing RHS value")(static_cast<void> (0));

if (getCurFunction()->SwitchStack.empty()) {
  Diag(CaseLoc, diag::err_case_not_in_switch);
  return StmtError();
}

if (LHSVal.isInvalid() || RHSVal.isInvalid()) {
  getCurFunction()->SwitchStack.back().setInt(true);
  return StmtError();
}

auto *CS = CaseStmt::Create(Context, LHSVal.get(), RHSVal.get(),
                            CaseLoc, DotDotDotLoc, ColonLoc);
getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(CS);
return CS;
515}

517/// ActOnCaseStmtBody - This installs a statement as the body of a case.
518void Sema::ActOnCaseStmtBody(Stmt *S, Stmt *SubStmt) {
cast<CaseStmt>(S)->setSubStmt(SubStmt);
520}

522StmtResult
523Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
                     Stmt *SubStmt, Scope *CurScope) {
if (getCurFunction()->SwitchStack.empty()) {
  Diag(DefaultLoc, diag::err_default_not_in_switch);
  return SubStmt;
}

DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(DS);
return DS;
533}

535StmtResult
536Sema::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 SubStmt;
}

ReservedIdentifierStatus Status = TheDecl->isReserved(getLangOpts());
if (Status != ReservedIdentifierStatus::NotReserved &&
    !Context.getSourceManager().isInSystemHeader(IdentLoc))
  Diag(IdentLoc, diag::warn_reserved_extern_symbol)
      << TheDecl << static_cast<int>(Status);

// 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->setLocStart(IdentLoc);
  if (!TheDecl->isMSAsmLabel()) {
    // Don't update the location of MS ASM labels.  These will result in
    // a diagnostic, and changing the location here will mess that up.
    TheDecl->setLocation(IdentLoc);
  }
}
return LS;
563}

565StmtResult Sema::BuildAttributedStmt(SourceLocation AttrsLoc,
                                   ArrayRef<const Attr *> Attrs,
                                   Stmt *SubStmt) {
// FIXME: this code should move when a planned refactoring around statement
// attributes lands.
for (const auto *A : Attrs) {
  if (A->getKind() == attr::MustTail) {
    if (!checkAndRewriteMustTailAttr(SubStmt, *A)) {
      return SubStmt;
    }
    setFunctionHasMustTail();
  }
}

return AttributedStmt::Create(Context, AttrsLoc, Attrs, SubStmt);
580}

582StmtResult Sema::ActOnAttributedStmt(const ParsedAttributesWithRange &Attrs,
                                   Stmt *SubStmt) {
SmallVector<const Attr *, 1> SemanticAttrs;
ProcessStmtAttributes(SubStmt, Attrs, SemanticAttrs);
if (!SemanticAttrs.empty())
  return BuildAttributedStmt(Attrs.Range.getBegin(), SemanticAttrs, SubStmt);
// If none of the attributes applied, that's fine, we can recover by
// returning the substatement directly instead of making an AttributedStmt
// with no attributes on it.
return SubStmt;
592}

594bool Sema::checkAndRewriteMustTailAttr(Stmt *St, const Attr &MTA) {
ReturnStmt *R = cast<ReturnStmt>(St);
Expr *E = R->getRetValue();

if (CurContext->isDependentContext() || (E && E->isInstantiationDependent()))
  // We have to suspend our check until template instantiation time.
  return true;

if (!checkMustTailAttr(St, MTA))
  return false;

// FIXME: Replace Expr::IgnoreImplicitAsWritten() with this function.
// Currently it does not skip implicit constructors in an initialization
// context.
auto IgnoreImplicitAsWritten = [](Expr *E) -> Expr * {
  return IgnoreExprNodes(E, IgnoreImplicitAsWrittenSingleStep,
                         IgnoreElidableImplicitConstructorSingleStep);
};

// Now that we have verified that 'musttail' is valid here, rewrite the
// return value to remove all implicit nodes, but retain parentheses.
R->setRetValue(IgnoreImplicitAsWritten(E));
return true;
617}

619bool Sema::checkMustTailAttr(const Stmt *St, const Attr &MTA) {
assert(!CurContext->isDependentContext() &&(static_cast<void> (0))
       "musttail cannot be checked from a dependent context")(static_cast<void> (0));

// FIXME: Add Expr::IgnoreParenImplicitAsWritten() with this definition.
auto IgnoreParenImplicitAsWritten = [](const Expr *E) -> const Expr * {
  return IgnoreExprNodes(const_cast<Expr *>(E), IgnoreParensSingleStep,
                         IgnoreImplicitAsWrittenSingleStep,
                         IgnoreElidableImplicitConstructorSingleStep);
};

const Expr *E = cast<ReturnStmt>(St)->getRetValue();
const auto *CE = dyn_cast_or_null<CallExpr>(IgnoreParenImplicitAsWritten(E));

if (!CE) {
  Diag(St->getBeginLoc(), diag::err_musttail_needs_call) << &MTA;
  return false;
}

if (const auto *EWC = dyn_cast<ExprWithCleanups>(E)) {
  if (EWC->cleanupsHaveSideEffects()) {
    Diag(St->getBeginLoc(), diag::err_musttail_needs_trivial_args) << &MTA;
    return false;
  }
}

// We need to determine the full function type (including "this" type, if any)
// for both caller and callee.
struct FuncType {
  enum {
    ft_non_member,
    ft_static_member,
    ft_non_static_member,
    ft_pointer_to_member,
  } MemberType = ft_non_member;

  QualType This;
  const FunctionProtoType *Func;
  const CXXMethodDecl *Method = nullptr;
} CallerType, CalleeType;

auto GetMethodType = [this, St, MTA](const CXXMethodDecl *CMD, FuncType &Type,
                                     bool IsCallee) -> bool {
  if (isa<CXXConstructorDecl, CXXDestructorDecl>(CMD)) {
    Diag(St->getBeginLoc(), diag::err_musttail_structors_forbidden)
        << IsCallee << isa<CXXDestructorDecl>(CMD);
    if (IsCallee)
      Diag(CMD->getBeginLoc(), diag::note_musttail_structors_forbidden)
          << isa<CXXDestructorDecl>(CMD);
    Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
    return false;
  }
  if (CMD->isStatic())
    Type.MemberType = FuncType::ft_static_member;
  else {
    Type.This = CMD->getThisType()->getPointeeType();
    Type.MemberType = FuncType::ft_non_static_member;
  }
  Type.Func = CMD->getType()->castAs<FunctionProtoType>();
  return true;
};

const auto *CallerDecl = dyn_cast<FunctionDecl>(CurContext);

// Find caller function signature.
if (!CallerDecl) {
  int ContextType;
  if (isa<BlockDecl>(CurContext))
    ContextType = 0;
  else if (isa<ObjCMethodDecl>(CurContext))
    ContextType = 1;
  else
    ContextType = 2;
  Diag(St->getBeginLoc(), diag::err_musttail_forbidden_from_this_context)
      << &MTA << ContextType;
  return false;
} else if (const auto *CMD = dyn_cast<CXXMethodDecl>(CurContext)) {
  // Caller is a class/struct method.
  if (!GetMethodType(CMD, CallerType, false))
    return false;
} else {
  // Caller is a non-method function.
  CallerType.Func = CallerDecl->getType()->getAs<FunctionProtoType>();
}

const Expr *CalleeExpr = CE->getCallee()->IgnoreParens();
const auto *CalleeBinOp = dyn_cast<BinaryOperator>(CalleeExpr);
SourceLocation CalleeLoc = CE->getCalleeDecl()
                               ? CE->getCalleeDecl()->getBeginLoc()
                               : St->getBeginLoc();

// Find callee function signature.
if (const CXXMethodDecl *CMD =
        dyn_cast_or_null<CXXMethodDecl>(CE->getCalleeDecl())) {
  // Call is: obj.method(), obj->method(), functor(), etc.
  if (!GetMethodType(CMD, CalleeType, true))
    return false;
} else if (CalleeBinOp && CalleeBinOp->isPtrMemOp()) {
  // Call is: obj->*method_ptr or obj.*method_ptr
  const auto *MPT =
      CalleeBinOp->getRHS()->getType()->castAs<MemberPointerType>();
  CalleeType.This = QualType(MPT->getClass(), 0);
  CalleeType.Func = MPT->getPointeeType()->castAs<FunctionProtoType>();
  CalleeType.MemberType = FuncType::ft_pointer_to_member;
} else if (isa<CXXPseudoDestructorExpr>(CalleeExpr)) {
  Diag(St->getBeginLoc(), diag::err_musttail_structors_forbidden)
      << /* IsCallee = */ 1 << /* IsDestructor = */ 1;
  Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
  return false;
} else {
  // Non-method function.
  CalleeType.Func =
      CalleeExpr->getType()->getPointeeType()->getAs<FunctionProtoType>();
}

// Both caller and callee must have a prototype (no K&R declarations).
if (!CalleeType.Func || !CallerType.Func) {
  Diag(St->getBeginLoc(), diag::err_musttail_needs_prototype) << &MTA;
  if (!CalleeType.Func && CE->getDirectCallee()) {
    Diag(CE->getDirectCallee()->getBeginLoc(),
         diag::note_musttail_fix_non_prototype);
  }
  if (!CallerType.Func)
    Diag(CallerDecl->getBeginLoc(), diag::note_musttail_fix_non_prototype);
  return false;
}

// Caller and callee must have matching calling conventions.
//
// Some calling conventions are physically capable of supporting tail calls
// even if the function types don't perfectly match. LLVM is currently too
// strict to allow this, but if LLVM added support for this in the future, we
// could exit early here and skip the remaining checks if the functions are
// using such a calling convention.
if (CallerType.Func->getCallConv() != CalleeType.Func->getCallConv()) {
  if (const auto *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl()))
    Diag(St->getBeginLoc(), diag::err_musttail_callconv_mismatch)
        << true << ND->getDeclName();
  else
    Diag(St->getBeginLoc(), diag::err_musttail_callconv_mismatch) << false;
  Diag(CalleeLoc, diag::note_musttail_callconv_mismatch)
      << FunctionType::getNameForCallConv(CallerType.Func->getCallConv())
      << FunctionType::getNameForCallConv(CalleeType.Func->getCallConv());
  Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
  return false;
}

if (CalleeType.Func->isVariadic() || CallerType.Func->isVariadic()) {
  Diag(St->getBeginLoc(), diag::err_musttail_no_variadic) << &MTA;
  return false;
}

// Caller and callee must match in whether they have a "this" parameter.
if (CallerType.This.isNull() != CalleeType.This.isNull()) {
  if (const auto *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
    Diag(St->getBeginLoc(), diag::err_musttail_member_mismatch)
        << CallerType.MemberType << CalleeType.MemberType << true
        << ND->getDeclName();
    Diag(CalleeLoc, diag::note_musttail_callee_defined_here)
        << ND->getDeclName();
  } else
    Diag(St->getBeginLoc(), diag::err_musttail_member_mismatch)
        << CallerType.MemberType << CalleeType.MemberType << false;
  Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
  return false;
}

auto CheckTypesMatch = [this](FuncType CallerType, FuncType CalleeType,
                              PartialDiagnostic &PD) -> bool {
  enum {
    ft_different_class,
    ft_parameter_arity,
    ft_parameter_mismatch,
    ft_return_type,
  };

  auto DoTypesMatch = [this, &PD](QualType A, QualType B,
                                  unsigned Select) -> bool {
    if (!Context.hasSimilarType(A, B)) {
      PD << Select << A.getUnqualifiedType() << B.getUnqualifiedType();
      return false;
    }
    return true;
  };

  if (!CallerType.This.isNull() &&
      !DoTypesMatch(CallerType.This, CalleeType.This, ft_different_class))
    return false;

  if (!DoTypesMatch(CallerType.Func->getReturnType(),
                    CalleeType.Func->getReturnType(), ft_return_type))
    return false;

  if (CallerType.Func->getNumParams() != CalleeType.Func->getNumParams()) {
    PD << ft_parameter_arity << CallerType.Func->getNumParams()
       << CalleeType.Func->getNumParams();
    return false;
  }

  ArrayRef<QualType> CalleeParams = CalleeType.Func->getParamTypes();
  ArrayRef<QualType> CallerParams = CallerType.Func->getParamTypes();
  size_t N = CallerType.Func->getNumParams();
  for (size_t I = 0; I < N; I++) {
    if (!DoTypesMatch(CalleeParams[I], CallerParams[I],
                      ft_parameter_mismatch)) {
      PD << static_cast<int>(I) + 1;
      return false;
    }
  }

  return true;
};

PartialDiagnostic PD = PDiag(diag::note_musttail_mismatch);
if (!CheckTypesMatch(CallerType, CalleeType, PD)) {
  if (const auto *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl()))
    Diag(St->getBeginLoc(), diag::err_musttail_mismatch)
        << true << ND->getDeclName();
  else
    Diag(St->getBeginLoc(), diag::err_musttail_mismatch) << false;
  Diag(CalleeLoc, PD);
  Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
  return false;
}

return true;
845}

847namespace {
848class CommaVisitor : public EvaluatedExprVisitor<CommaVisitor> {
typedef EvaluatedExprVisitor<CommaVisitor> Inherited;
Sema &SemaRef;
851public:
CommaVisitor(Sema &SemaRef) : Inherited(SemaRef.Context), SemaRef(SemaRef) {}
void VisitBinaryOperator(BinaryOperator *E) {
  if (E->getOpcode() == BO_Comma)
    SemaRef.DiagnoseCommaOperator(E->getLHS(), E->getExprLoc());
  EvaluatedExprVisitor<CommaVisitor>::VisitBinaryOperator(E);
}
858};
859}

861StmtResult Sema::ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr,
                           SourceLocation LParenLoc, Stmt *InitStmt,
                           ConditionResult Cond, SourceLocation RParenLoc,
                           Stmt *thenStmt, SourceLocation ElseLoc,
                           Stmt *elseStmt) {
if (Cond.isInvalid())
  Cond = ConditionResult(
      *this, nullptr,
      MakeFullExpr(new (Context) OpaqueValueExpr(SourceLocation(),
                                                 Context.BoolTy, VK_PRValue),
                   IfLoc),
      false);

Expr *CondExpr = Cond.get().second;
// Only call the CommaVisitor when not C89 due to differences in scope flags.
if ((getLangOpts().C99 || getLangOpts().CPlusPlus) &&
    !Diags.isIgnored(diag::warn_comma_operator, CondExpr->getExprLoc()))
  CommaVisitor(*this).Visit(CondExpr);

if (!elseStmt)
  DiagnoseEmptyStmtBody(CondExpr->getEndLoc(), thenStmt,
                        diag::warn_empty_if_body);

if (IsConstexpr) {
  auto DiagnoseLikelihood = [&](const Stmt *S) {
    if (const Attr *A = Stmt::getLikelihoodAttr(S)) {
      Diags.Report(A->getLocation(),
                   diag::warn_attribute_has_no_effect_on_if_constexpr)
          << A << A->getRange();
      Diags.Report(IfLoc,
                   diag::note_attribute_has_no_effect_on_if_constexpr_here)
          << SourceRange(IfLoc, LParenLoc.getLocWithOffset(-1));
    }
  };
  DiagnoseLikelihood(thenStmt);
  DiagnoseLikelihood(elseStmt);
} else {
  std::tuple<bool, const Attr *, const Attr *> LHC =
      Stmt::determineLikelihoodConflict(thenStmt, elseStmt);
  if (std::get<0>(LHC)) {
    const Attr *ThenAttr = std::get<1>(LHC);
    const Attr *ElseAttr = std::get<2>(LHC);
    Diags.Report(ThenAttr->getLocation(),
                 diag::warn_attributes_likelihood_ifstmt_conflict)
        << ThenAttr << ThenAttr->getRange();
    Diags.Report(ElseAttr->getLocation(), diag::note_conflicting_attribute)
        << ElseAttr << ElseAttr->getRange();
  }
}

return BuildIfStmt(IfLoc, IsConstexpr, LParenLoc, InitStmt, Cond, RParenLoc,
                   thenStmt, ElseLoc, elseStmt);
913}

915StmtResult Sema::BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
                           SourceLocation LParenLoc, Stmt *InitStmt,
                           ConditionResult Cond, SourceLocation RParenLoc,
                           Stmt *thenStmt, SourceLocation ElseLoc,
                           Stmt *elseStmt) {
if (Cond.isInvalid())
  return StmtError();

if (IsConstexpr || isa<ObjCAvailabilityCheckExpr>(Cond.get().second))
  setFunctionHasBranchProtectedScope();

return IfStmt::Create(Context, IfLoc, IsConstexpr, InitStmt, Cond.get().first,
                      Cond.get().second, LParenLoc, RParenLoc, thenStmt,
                      ElseLoc, elseStmt);
929}

931namespace {
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;
  }
};
946}

948/// CmpCaseVals - Comparison predicate for sorting case values.
949///
950static 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() < rhs.second->getCaseLoc())
  return true;
return false;
959}

961/// CmpEnumVals - Comparison predicate for sorting enumeration values.
962///
963static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
                      const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
965{
return lhs.first < rhs.first;
967}

969/// EqEnumVals - Comparison preficate for uniqing enumeration values.
970///
971static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
                     const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
973{
return lhs.first == rhs.first;
975}

977/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
978/// potentially integral-promoted expression @p expr.
979static QualType GetTypeBeforeIntegralPromotion(const Expr *&E) {
if (const auto *FE = dyn_cast<FullExpr>(E))
  E = FE->getSubExpr();
while (const auto *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
  if (ImpCast->getCastKind() != CK_IntegralCast) break;
  E = ImpCast->getSubExpr();
}
return E->getType();
987}

989ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
  Expr *Cond;

public:
  SwitchConvertDiagnoser(Expr *Cond)
      : ICEConvertDiagnoser(/*AllowScopedEnumerations*/true, false, true),
        Cond(Cond) {}

  SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
                                       QualType T) override {
    return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T;
  }

  SemaDiagnosticBuilder diagnoseIncomplete(
      Sema &S, SourceLocation Loc, QualType T) override {
    return S.Diag(Loc, diag::err_switch_incomplete_class_type)
             << T << Cond->getSourceRange();
  }

  SemaDiagnosticBuilder diagnoseExplicitConv(
      Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
    return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy;
  }

  SemaDiagnosticBuilder noteExplicitConv(
      Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
    return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
      << ConvTy->isEnumeralType() << ConvTy;
  }

  SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
                                          QualType T) override {
    return S.Diag(Loc, diag::err_switch_multiple_conversions) << T;
  }

  SemaDiagnosticBuilder noteAmbiguous(
      Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
    return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
    << ConvTy->isEnumeralType() << ConvTy;
  }

  SemaDiagnosticBuilder diagnoseConversion(
      Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
    llvm_unreachable("conversion functions are permitted")__builtin_unreachable();
  }
} SwitchDiagnoser(Cond);

ExprResult CondResult =
    PerformContextualImplicitConversion(SwitchLoc, Cond, SwitchDiagnoser);
if (CondResult.isInvalid())
  return ExprError();

// FIXME: PerformContextualImplicitConversion doesn't always tell us if it
// failed and produced a diagnostic.
Cond = CondResult.get();
if (!Cond->isTypeDependent() &&
    !Cond->getType()->isIntegralOrEnumerationType())
  return ExprError();

// C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
return UsualUnaryConversions(Cond);
1051}

1053StmtResult Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
                                      SourceLocation LParenLoc,
                                      Stmt *InitStmt, ConditionResult Cond,
                                      SourceLocation RParenLoc) {
Expr *CondExpr = Cond.get().second;
assert((Cond.isInvalid() || CondExpr) && "switch with no condition")(static_cast<void> (0));

if (CondExpr && !CondExpr->isTypeDependent()) {
  // We have already converted the expression to an integral or enumeration
  // type, when we parsed the switch condition. There are cases where we don't
  // have an appropriate type, e.g. a typo-expr Cond was corrected to an
  // inappropriate-type expr, we just return an error.
  if (!CondExpr->getType()->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();
  }
}

setFunctionHasBranchIntoScope();

auto *SS = SwitchStmt::Create(Context, InitStmt, Cond.get().first, CondExpr,
                              LParenLoc, RParenLoc);
getCurFunction()->SwitchStack.push_back(
    FunctionScopeInfo::SwitchInfo(SS, false));
return SS;
1083}

1085static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
Val = Val.extOrTrunc(BitWidth);
Val.setIsSigned(IsSigned);
1088}

1090/// Check the specified case value is in range for the given unpromoted switch
1091/// type.
1092static void checkCaseValue(Sema &S, SourceLocation Loc, const llvm::APSInt &Val,
                         unsigned UnpromotedWidth, bool UnpromotedSign) {
// In C++11 onwards, this is checked by the language rules.
if (S.getLangOpts().CPlusPlus11)
  return;

// If the case value was signed and negative and the switch expression is
// unsigned, don't bother to warn: this is implementation-defined behavior.
// FIXME: Introduce a second, default-ignored warning for this case?
if (UnpromotedWidth < Val.getBitWidth()) {
  llvm::APSInt ConvVal(Val);
  AdjustAPSInt(ConvVal, UnpromotedWidth, UnpromotedSign);
  AdjustAPSInt(ConvVal, Val.getBitWidth(), Val.isSigned());
  // FIXME: Use different diagnostics for overflow  in conversion to promoted
  // type versus "switch expression cannot have this value". Use proper
  // IntRange checking rather than just looking at the unpromoted type here.
  if (ConvVal != Val)
    S.Diag(Loc, diag::warn_case_value_overflow) << toString(Val, 10)
                                                << toString(ConvVal, 10);
}
1112}

1114typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy;

1116/// Returns true if we should emit a diagnostic about this case expression not
1117/// being a part of the enum used in the switch controlling expression.
1118static bool ShouldDiagnoseSwitchCaseNotInEnum(const Sema &S,
                                            const EnumDecl *ED,
                                            const Expr *CaseExpr,
                                            EnumValsTy::iterator &EI,
                                            EnumValsTy::iterator &EIEnd,
                                            const llvm::APSInt &Val) {
if (!ED->isClosed())
  return false;

if (const DeclRefExpr *DRE =
        dyn_cast<DeclRefExpr>(CaseExpr->IgnoreParenImpCasts())) {
  if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
    QualType VarType = VD->getType();
    QualType EnumType = S.Context.getTypeDeclType(ED);
    if (VD->hasGlobalStorage() && VarType.isConstQualified() &&
        S.Context.hasSameUnqualifiedType(EnumType, VarType))
      return false;
  }
}

if (ED->hasAttr<FlagEnumAttr>())
  return !S.IsValueInFlagEnum(ED, Val, false);

while (EI != EIEnd && EI->first < Val)
  EI++;

if (EI != EIEnd && EI->first == Val)
  return false;

return true;
1148}

1150static void checkEnumTypesInSwitchStmt(Sema &S, const Expr *Cond,
                                     const Expr *Case) {
QualType CondType = Cond->getType();
QualType CaseType = Case->getType();

const EnumType *CondEnumType = CondType->getAs<EnumType>();
const EnumType *CaseEnumType = CaseType->getAs<EnumType>();
if (!CondEnumType || !CaseEnumType)
  return;

// Ignore anonymous enums.
if (!CondEnumType->getDecl()->getIdentifier() &&
    !CondEnumType->getDecl()->getTypedefNameForAnonDecl())
  return;
if (!CaseEnumType->getDecl()->getIdentifier() &&
    !CaseEnumType->getDecl()->getTypedefNameForAnonDecl())
  return;

if (S.Context.hasSameUnqualifiedType(CondType, CaseType))
  return;

S.Diag(Case->getExprLoc(), diag::warn_comparison_of_mixed_enum_types_switch)
    << CondType << CaseType << Cond->getSourceRange()
    << Case->getSourceRange();
1174}

1176StmtResult
1177Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
                          Stmt *BodyStmt) {
SwitchStmt *SS = cast<SwitchStmt>(Switch);
bool CaseListIsIncomplete = getCurFunction()->SwitchStack.back().getInt();
assert(SS == getCurFunction()->SwitchStack.back().getPointer() &&(static_cast<void> (0))
       "switch stack missing push/pop!")(static_cast<void> (0));

getCurFunction()->SwitchStack.pop_back();

if (!BodyStmt) return StmtError();
SS->setBody(BodyStmt, SwitchLoc);

Expr *CondExpr = SS->getCond();
if (!CondExpr) return StmtError();

QualType CondType = CondExpr->getType();

// 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.
const Expr *CondExprBeforePromotion = CondExpr;
QualType CondTypeBeforePromotion =
    GetTypeBeforeIntegralPromotion(CondExprBeforePromotion);

// Get the bitwidth of the switched-on value after 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(CondType);
bool CondIsSigned = CondType->isSignedIntegerOrEnumerationType();

// Get the width and signedness that the condition might actually have, for
// warning purposes.
// FIXME: Grab an IntRange for the condition rather than using the unpromoted
// type.
unsigned CondWidthBeforePromotion
  = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion);
bool CondIsSignedBeforePromotion
  = 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 = nullptr;

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->isValueDependent()) {
      HasDependentValue = true;
      break;
    }

    // We already verified that the expression has a constant value;
    // get that value (prior to conversions).
    const Expr *LoBeforePromotion = Lo;
    GetTypeBeforeIntegralPromotion(LoBeforePromotion);
    llvm::APSInt LoVal = LoBeforePromotion->EvaluateKnownConstInt(Context);

    // Check the unconverted value is within the range of possible values of
    // the switch expression.
    checkCaseValue(*this, Lo->getBeginLoc(), LoVal, CondWidthBeforePromotion,
                   CondIsSignedBeforePromotion);

    // FIXME: This duplicates the check performed for warn_not_in_enum below.
    checkEnumTypesInSwitchStmt(*this, CondExprBeforePromotion,
                               LoBeforePromotion);

    // Convert the value to the same width/sign as the condition.
    AdjustAPSInt(LoVal, CondWidth, CondIsSigned);

    // If this is a case range, remember it in CaseRanges, otherwise CaseVals.
    if (CS->getRHS()) {
      if (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 (!TheDefaultStmt) {
    Expr::EvalResult Result;
    HasConstantCond = CondExpr->EvaluateAsInt(Result, Context,
                                              Expr::SE_AllowSideEffects);
    if (Result.Val.isInt())
      ConstantCondValue = Result.Val.getInt();
    assert(!HasConstantCond ||(static_cast<void> (0))
           (ConstantCondValue.getBitWidth() == CondWidth &&(static_cast<void> (0))
            ConstantCondValue.isSigned() == CondIsSigned))(static_cast<void> (0));
  }
  bool ShouldCheckConstantCond = HasConstantCond;

  // Sort all the scalar case values so we can easily detect duplicates.
  llvm::stable_sort(CaseVals, 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.
        // First, determine if either case value has a name
        StringRef PrevString, CurrString;
        Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts();
        Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts();
        if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(PrevCase)) {
          PrevString = DeclRef->getDecl()->getName();
        }
        if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(CurrCase)) {
          CurrString = DeclRef->getDecl()->getName();
        }
        SmallString<16> CaseValStr;
        CaseVals[i-1].first.toString(CaseValStr);

        if (PrevString == CurrString)
          Diag(CaseVals[i].second->getLHS()->getBeginLoc(),
               diag::err_duplicate_case)
              << (PrevString.empty() ? CaseValStr.str() : PrevString);
        else
          Diag(CaseVals[i].second->getLHS()->getBeginLoc(),
               diag::err_duplicate_case_differing_expr)
              << (PrevString.empty() ? CaseValStr.str() : PrevString)
              << (CurrString.empty() ? CaseValStr.str() : CurrString)
              << CaseValStr;

        Diag(CaseVals[i - 1].second->getLHS()->getBeginLoc(),
             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.
    llvm::stable_sort(CaseRanges);

    // 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();

      const Expr *HiBeforePromotion = Hi;
      GetTypeBeforeIntegralPromotion(HiBeforePromotion);
      llvm::APSInt HiVal = HiBeforePromotion->EvaluateKnownConstInt(Context);

      // Check the unconverted value is within the range of possible values of
      // the switch expression.
      checkCaseValue(*this, Hi->getBeginLoc(), HiVal,
                     CondWidthBeforePromotion, CondIsSignedBeforePromotion);

      // Convert the value to the same width/sign as the condition.
      AdjustAPSInt(HiVal, CondWidth, CondIsSigned);

      // If the low value is bigger than the high value, the case is empty.
      if (LoVal > HiVal) {
        Diag(CR->getLHS()->getBeginLoc(), diag::warn_case_empty_range)
            << SourceRange(CR->getLHS()->getBeginLoc(), Hi->getEndLoc());
        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 = nullptr;
      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 =
          llvm::lower_bound(CaseVals, 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()->getBeginLoc(), diag::err_duplicate_case)
            << toString(OverlapVal, 10);
        Diag(OverlapStmt->getLHS()->getBeginLoc(),
             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 && !CaseListIsIncomplete &&
      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)
      << toString(ConstantCondValue, 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 && !CaseListIsIncomplete && !HasConstantCond &&
      ET && ET->getDecl()->isCompleteDefinition() &&
      !empty(ET->getDecl()->enumerators())) {
    const EnumDecl *ED = ET->getDecl();
    EnumValsTy EnumVals;

    // Gather all enum values, set their type and sort them,
    // allowing easier comparison with CaseVals.
    for (auto *EDI : ED->enumerators()) {
      llvm::APSInt Val = EDI->getInitVal();
      AdjustAPSInt(Val, CondWidth, CondIsSigned);
      EnumVals.push_back(std::make_pair(Val, EDI));
    }
    llvm::stable_sort(EnumVals, CmpEnumVals);
    auto EI = EnumVals.begin(), EIEnd =
      std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);

    // See which case values aren't in enum.
    for (CaseValsTy::const_iterator CI = CaseVals.begin();
        CI != CaseVals.end(); CI++) {
      Expr *CaseExpr = CI->second->getLHS();
      if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
                                            CI->first))
        Diag(CaseExpr->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(); RI++) {
      Expr *CaseExpr = RI->second->getLHS();
      if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
                                            RI->first))
        Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
          << CondTypeBeforePromotion;

      llvm::APSInt Hi =
        RI->second->getRHS()->EvaluateKnownConstInt(Context);
      AdjustAPSInt(Hi, CondWidth, CondIsSigned);

      CaseExpr = RI->second->getRHS();
      if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
                                            Hi))
        Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
          << CondTypeBeforePromotion;
    }

    // Check which enum vals aren't in switch
    auto CI = CaseVals.begin();
    auto RI = CaseRanges.begin();
    bool hasCasesNotInSwitch = false;

    SmallVector<DeclarationName,8> UnhandledNames;

    for (EI = EnumVals.begin(); EI != EIEnd; EI++) {
      // Don't warn about omitted unavailable EnumConstantDecls.
      switch (EI->second->getAvailability()) {
      case AR_Deprecated:
        // Omitting a deprecated constant is ok; it should never materialize.
      case AR_Unavailable:
        continue;

      case AR_NotYetIntroduced:
        // Partially available enum constants should be present. Note that we
        // suppress -Wunguarded-availability diagnostics for such uses.
      case AR_Available:
        break;
      }

      if (EI->second->hasAttr<UnusedAttr>())
        continue;

      // Drop unneeded case values
      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() && ED->isClosedNonFlag())
      Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default);

    // Produce a nice diagnostic if multiple values aren't handled.
    if (!UnhandledNames.empty()) {
      auto DB = Diag(CondExpr->getExprLoc(), TheDefaultStmt
                                                 ? diag::warn_def_missing_case
                                                 : diag::warn_missing_case)
                << CondExpr->getSourceRange() << (int)UnhandledNames.size();

      for (size_t I = 0, E = std::min(UnhandledNames.size(), (size_t)3);
           I != E; ++I)
        DB << UnhandledNames[I];
    }

    if (!hasCasesNotInSwitch)
      SS->setAllEnumCasesCovered();
  }
}

if (BodyStmt)
  DiagnoseEmptyStmtBody(CondExpr->getEndLoc(), 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 SS;
1588}

1590void
1591Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
                           Expr *SrcExpr) {
if (Diags.isIgnored(diag::warn_not_in_enum_assignment, SrcExpr->getExprLoc()))
  return;

if (const EnumType *ET = DstType->getAs<EnumType>())
  if (!Context.hasSameUnqualifiedType(SrcType, DstType) &&
      SrcType->isIntegerType()) {
    if (!SrcExpr->isTypeDependent() && !SrcExpr->isValueDependent() &&
        SrcExpr->isIntegerConstantExpr(Context)) {
      // Get the bitwidth of the enum value before promotions.
      unsigned DstWidth = Context.getIntWidth(DstType);
      bool DstIsSigned = DstType->isSignedIntegerOrEnumerationType();

      llvm::APSInt RhsVal = SrcExpr->EvaluateKnownConstInt(Context);
      AdjustAPSInt(RhsVal, DstWidth, DstIsSigned);
      const EnumDecl *ED = ET->getDecl();

      if (!ED->isClosed())
        return;

      if (ED->hasAttr<FlagEnumAttr>()) {
        if (!IsValueInFlagEnum(ED, RhsVal, true))
          Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
            << DstType.getUnqualifiedType();
      } else {
        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 rhs constant.
        for (auto *EDI : ED->enumerators()) {
          llvm::APSInt Val = EDI->getInitVal();
          AdjustAPSInt(Val, DstWidth, DstIsSigned);
          EnumVals.push_back(std::make_pair(Val, EDI));
        }
        if (EnumVals.empty())
          return;
        llvm::stable_sort(EnumVals, CmpEnumVals);
        EnumValsTy::iterator EIend =
            std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);

        // See which values aren't in the enum.
        EnumValsTy::const_iterator EI = EnumVals.begin();
        while (EI != EIend && EI->first < RhsVal)
          EI++;
        if (EI == EIend || EI->first != RhsVal) {
          Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
              << DstType.getUnqualifiedType();
        }
      }
    }
  }
1645}

1647StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc,
                              SourceLocation LParenLoc, ConditionResult Cond,
                              SourceLocation RParenLoc, Stmt *Body) {
if (Cond.isInvalid())
  return StmtError();

auto CondVal = Cond.get();
CheckBreakContinueBinding(CondVal.second);

if (CondVal.second &&
    !Diags.isIgnored(diag::warn_comma_operator, CondVal.second->getExprLoc()))
  CommaVisitor(*this).Visit(CondVal.second);

if (isa<NullStmt>(Body))
  getCurCompoundScope().setHasEmptyLoopBodies();

return WhileStmt::Create(Context, CondVal.first, CondVal.second, Body,
                         WhileLoc, LParenLoc, RParenLoc);
1665}

1667StmtResult
1668Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
                SourceLocation WhileLoc, SourceLocation CondLParen,
                Expr *Cond, SourceLocation CondRParen) {
assert(Cond && "ActOnDoStmt(): missing expression")(static_cast<void> (0));

CheckBreakContinueBinding(Cond);
ExprResult CondResult = CheckBooleanCondition(DoLoc, Cond);
if (CondResult.isInvalid())
  return StmtError();
Cond = CondResult.get();

CondResult = ActOnFinishFullExpr(Cond, DoLoc, /*DiscardedValue*/ false);
if (CondResult.isInvalid())
  return StmtError();
Cond = CondResult.get();

// Only call the CommaVisitor for C89 due to differences in scope flags.
if (Cond && !getLangOpts().C99 && !getLangOpts().CPlusPlus &&
    !Diags.isIgnored(diag::warn_comma_operator, Cond->getExprLoc()))
  CommaVisitor(*this).Visit(Cond);

return new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen);
1690}

1692namespace {
// Use SetVector since the diagnostic cares about the ordering of the Decl's.
using DeclSetVector =
    llvm::SetVector<VarDecl *, llvm::SmallVector<VarDecl *, 8>,
                    llvm::SmallPtrSet<VarDecl *, 8>>;

// This visitor will traverse a conditional statement and store all
// the evaluated decls into a vector.  Simple is set to true if none
// of the excluded constructs are used.
class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> {
  DeclSetVector &Decls;
  SmallVectorImpl<SourceRange> &Ranges;
  bool Simple;
public:
  typedef EvaluatedExprVisitor<DeclExtractor> Inherited;

  DeclExtractor(Sema &S, DeclSetVector &Decls,
                SmallVectorImpl<SourceRange> &Ranges) :
      Inherited(S.Context),
      Decls(Decls),
      Ranges(Ranges),
      Simple(true) {}

  bool isSimple() { return Simple; }

  // Replaces the method in EvaluatedExprVisitor.
  void VisitMemberExpr(MemberExpr* E) {
    Simple = false;
  }

  // Any Stmt not explicitly listed will cause the condition to be marked
  // complex.
  void VisitStmt(Stmt *S) { Simple = false; }

  void VisitBinaryOperator(BinaryOperator *E) {
    Visit(E->getLHS());
    Visit(E->getRHS());
  }

  void VisitCastExpr(CastExpr *E) {
    Visit(E->getSubExpr());
  }

  void VisitUnaryOperator(UnaryOperator *E) {
    // Skip checking conditionals with derefernces.
    if (E->getOpcode() == UO_Deref)
      Simple = false;
    else
      Visit(E->getSubExpr());
  }

  void VisitConditionalOperator(ConditionalOperator *E) {
    Visit(E->getCond());
    Visit(E->getTrueExpr());
    Visit(E->getFalseExpr());
  }

  void VisitParenExpr(ParenExpr *E) {
    Visit(E->getSubExpr());
  }

  void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
    Visit(E->getOpaqueValue()->getSourceExpr());
    Visit(E->getFalseExpr());
  }

  void VisitIntegerLiteral(IntegerLiteral *E) { }
  void VisitFloatingLiteral(FloatingLiteral *E) { }
  void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { }
  void VisitCharacterLiteral(CharacterLiteral *E) { }
  void VisitGNUNullExpr(GNUNullExpr *E) { }
  void VisitImaginaryLiteral(ImaginaryLiteral *E) { }

  void VisitDeclRefExpr(DeclRefExpr *E) {
    VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
    if (!VD) {
      // Don't allow unhandled Decl types.
      Simple = false;
      return;
    }

    Ranges.push_back(E->getSourceRange());

    Decls.insert(VD);
  }

}; // end class DeclExtractor

// DeclMatcher checks to see if the decls are used in a non-evaluated
// context.
class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> {
  DeclSetVector &Decls;
  bool FoundDecl;

public:
  typedef EvaluatedExprVisitor<DeclMatcher> Inherited;

  DeclMatcher(Sema &S, DeclSetVector &Decls, Stmt *Statement) :
      Inherited(S.Context), Decls(Decls), FoundDecl(false) {
    if (!Statement) return;

    Visit(Statement);
  }

  void VisitReturnStmt(ReturnStmt *S) {
    FoundDecl = true;
  }

  void VisitBreakStmt(BreakStmt *S) {
    FoundDecl = true;
  }

  void VisitGotoStmt(GotoStmt *S) {
    FoundDecl = true;
  }

  void VisitCastExpr(CastExpr *E) {
    if (E->getCastKind() == CK_LValueToRValue)
      CheckLValueToRValueCast(E->getSubExpr());
    else
      Visit(E->getSubExpr());
  }

  void CheckLValueToRValueCast(Expr *E) {
    E = E->IgnoreParenImpCasts();

    if (isa<DeclRefExpr>(E)) {
      return;
    }

    if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
      Visit(CO->getCond());
      CheckLValueToRValueCast(CO->getTrueExpr());
      CheckLValueToRValueCast(CO->getFalseExpr());
      return;
    }

    if (BinaryConditionalOperator *BCO =
            dyn_cast<BinaryConditionalOperator>(E)) {
      CheckLValueToRValueCast(BCO->getOpaqueValue()->getSourceExpr());
      CheckLValueToRValueCast(BCO->getFalseExpr());
      return;
    }

    Visit(E);
  }

  void VisitDeclRefExpr(DeclRefExpr *E) {
    if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
      if (Decls.count(VD))
        FoundDecl = true;
  }

  void VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
    // Only need to visit the semantics for POE.
    // SyntaticForm doesn't really use the Decal.
    for (auto *S : POE->semantics()) {
      if (auto *OVE = dyn_cast<OpaqueValueExpr>(S))
        // Look past the OVE into the expression it binds.
        Visit(OVE->getSourceExpr());
      else
        Visit(S);
    }
  }

  bool FoundDeclInUse() { return FoundDecl; }

};  // end class DeclMatcher

void CheckForLoopConditionalStatement(Sema &S, Expr *Second,
                                      Expr *Third, Stmt *Body) {
  // Condition is empty
  if (!Second) return;

  if (S.Diags.isIgnored(diag::warn_variables_not_in_loop_body,
                        Second->getBeginLoc()))
    return;

  PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body);
  DeclSetVector Decls;
  SmallVector<SourceRange, 10> Ranges;
  DeclExtractor DE(S, Decls, Ranges);
  DE.Visit(Second);

  // Don't analyze complex conditionals.
  if (!DE.isSimple()) return;

  // No decls found.
  if (Decls.size() == 0) return;

  // Don't warn on volatile, static, or global variables.
  for (auto *VD : Decls)
    if (VD->getType().isVolatileQualified() || VD->hasGlobalStorage())
      return;

  if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
      DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
      DeclMatcher(S, Decls, Body).FoundDeclInUse())
    return;

  // Load decl names into diagnostic.
  if (Decls.size() > 4) {
    PDiag << 0;
  } else {
    PDiag << (unsigned)Decls.size();
    for (auto *VD : Decls)
      PDiag << VD->getDeclName();
  }

  for (auto Range : Ranges)
    PDiag << Range;

  S.Diag(Ranges.begin()->getBegin(), PDiag);
}

// If Statement is an incemement or decrement, return true and sets the
// variables Increment and DRE.
bool ProcessIterationStmt(Sema &S, Stmt* Statement, bool &Increment,
                          DeclRefExpr *&DRE) {
  if (auto Cleanups = dyn_cast<ExprWithCleanups>(Statement))
    if (!Cleanups->cleanupsHaveSideEffects())
      Statement = Cleanups->getSubExpr();

  if (UnaryOperator *UO = dyn_cast<UnaryOperator>(Statement)) {
    switch (UO->getOpcode()) {
      default: return false;
      case UO_PostInc:
      case UO_PreInc:
        Increment = true;
        break;
      case UO_PostDec:
      case UO_PreDec:
        Increment = false;
        break;
    }
    DRE = dyn_cast<DeclRefExpr>(UO->getSubExpr());
    return DRE;
  }

  if (CXXOperatorCallExpr *Call = dyn_cast<CXXOperatorCallExpr>(Statement)) {
    FunctionDecl *FD = Call->getDirectCallee();
    if (!FD || !FD->isOverloadedOperator()) return false;
    switch (FD->getOverloadedOperator()) {
      default: return false;
      case OO_PlusPlus:
        Increment = true;
        break;
      case OO_MinusMinus:
        Increment = false;
        break;
    }
    DRE = dyn_cast<DeclRefExpr>(Call->getArg(0));
    return DRE;
  }

  return false;
}

// A visitor to determine if a continue or break statement is a
// subexpression.
class BreakContinueFinder : public ConstEvaluatedExprVisitor<BreakContinueFinder> {
  SourceLocation BreakLoc;
  SourceLocation ContinueLoc;
  bool InSwitch = false;

public:
  BreakContinueFinder(Sema &S, const Stmt* Body) :
      Inherited(S.Context) {
    Visit(Body);
  }

  typedef ConstEvaluatedExprVisitor<BreakContinueFinder> Inherited;

  void VisitContinueStmt(const ContinueStmt* E) {
    ContinueLoc = E->getContinueLoc();
  }

  void VisitBreakStmt(const BreakStmt* E) {
    if (!InSwitch)
      BreakLoc = E->getBreakLoc();
  }

  void VisitSwitchStmt(const SwitchStmt* S) {
    if (const Stmt *Init = S->getInit())
      Visit(Init);
    if (const Stmt *CondVar = S->getConditionVariableDeclStmt())
      Visit(CondVar);
    if (const Stmt *Cond = S->getCond())
      Visit(Cond);

    // Don't return break statements from the body of a switch.
    InSwitch = true;
    if (const Stmt *Body = S->getBody())
      Visit(Body);
    InSwitch = false;
  }

  void VisitForStmt(const ForStmt *S) {
    // Only visit the init statement of a for loop; the body
    // has a different break/continue scope.
    if (const Stmt *Init = S->getInit())
      Visit(Init);
  }

  void VisitWhileStmt(const WhileStmt *) {
    // Do nothing; the children of a while loop have a different
    // break/continue scope.
  }

  void VisitDoStmt(const DoStmt *) {
    // Do nothing; the children of a while loop have a different
    // break/continue scope.
  }

  void VisitCXXForRangeStmt(const CXXForRangeStmt *S) {
    // Only visit the initialization of a for loop; the body
    // has a different break/continue scope.
    if (const Stmt *Init = S->getInit())
      Visit(Init);
    if (const Stmt *Range = S->getRangeStmt())
      Visit(Range);
    if (const Stmt *Begin = S->getBeginStmt())
      Visit(Begin);
    if (const Stmt *End = S->getEndStmt())
      Visit(End);
  }

  void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
    // Only visit the initialization of a for loop; the body
    // has a different break/continue scope.
    if (const Stmt *Element = S->getElement())
      Visit(Element);
    if (const Stmt *Collection = S->getCollection())
      Visit(Collection);
  }

  bool ContinueFound() { return ContinueLoc.isValid(); }
  bool BreakFound() { return BreakLoc.isValid(); }
  SourceLocation GetContinueLoc() { return ContinueLoc; }
  SourceLocation GetBreakLoc() { return BreakLoc; }

};  // end class BreakContinueFinder

// Emit a warning when a loop increment/decrement appears twice per loop
// iteration.  The conditions which trigger this warning are:
// 1) The last statement in the loop body and the third expression in the
//    for loop are both increment or both decrement of the same variable
// 2) No continue statements in the loop body.
void CheckForRedundantIteration(Sema &S, Expr *Third, Stmt *Body) {
  // Return when there is nothing to check.
  if (!Body || !Third) return;

  if (S.Diags.isIgnored(diag::warn_redundant_loop_iteration,
                        Third->getBeginLoc()))
    return;

  // Get the last statement from the loop body.
  CompoundStmt *CS = dyn_cast<CompoundStmt>(Body);
  if (!CS || CS->body_empty()) return;
  Stmt *LastStmt = CS->body_back();
  if (!LastStmt) return;

  bool LoopIncrement, LastIncrement;
  DeclRefExpr *LoopDRE, *LastDRE;

  if (!ProcessIterationStmt(S, Third, LoopIncrement, LoopDRE)) return;
  if (!ProcessIterationStmt(S, LastStmt, LastIncrement, LastDRE)) return;

  // Check that the two statements are both increments or both decrements
  // on the same variable.
  if (LoopIncrement != LastIncrement ||
      LoopDRE->getDecl() != LastDRE->getDecl()) return;

  if (BreakContinueFinder(S, Body).ContinueFound()) return;

  S.Diag(LastDRE->getLocation(), diag::warn_redundant_loop_iteration)
       << LastDRE->getDecl() << LastIncrement;
  S.Diag(LoopDRE->getLocation(), diag::note_loop_iteration_here)
       << LoopIncrement;
}

2073} // end namespace


2076void Sema::CheckBreakContinueBinding(Expr *E) {
if (!E || getLangOpts().CPlusPlus)
  return;
BreakContinueFinder BCFinder(*this, E);
Scope *BreakParent = CurScope->getBreakParent();
if (BCFinder.BreakFound() && BreakParent) {
  if (BreakParent->getFlags() & Scope::SwitchScope) {
    Diag(BCFinder.GetBreakLoc(), diag::warn_break_binds_to_switch);
  } else {
    Diag(BCFinder.GetBreakLoc(), diag::warn_loop_ctrl_binds_to_inner)
        << "break";
  }
} else if (BCFinder.ContinueFound() && CurScope->getContinueParent()) {
  Diag(BCFinder.GetContinueLoc(), diag::warn_loop_ctrl_binds_to_inner)
      << "continue";
}
2092}

2094StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
                            Stmt *First, ConditionResult Second,
                            FullExprArg third, SourceLocation RParenLoc,
                            Stmt *Body) {
if (Second.isInvalid())
  return StmtError();

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'.
    const Decl *NonVarSeen = nullptr;
    bool VarDeclSeen = false;
    for (auto *DI : DS->decls()) {
      if (VarDecl *VD = dyn_cast<VarDecl>(DI)) {
        VarDeclSeen = true;
        if (VD->isLocalVarDecl() && !VD->hasLocalStorage()) {
          Diag(DI->getLocation(), diag::err_non_local_variable_decl_in_for);
          DI->setInvalidDecl();
        }
      } else if (!NonVarSeen) {
        // Keep track of the first non-variable declaration we saw so that
        // we can diagnose if we don't see any variable declarations. This
        // covers a case like declaring a typedef, function, or structure
        // type rather than a variable.
        NonVarSeen = DI;
      }
    }
    // Diagnose if we saw a non-variable declaration but no variable
    // declarations.
    if (NonVarSeen && !VarDeclSeen)
      Diag(NonVarSeen->getLocation(), diag::err_non_variable_decl_in_for);
  }
}

CheckBreakContinueBinding(Second.get().second);
CheckBreakContinueBinding(third.get());

if (!Second.get().first)
  CheckForLoopConditionalStatement(*this, Second.get().second, third.get(),
                                   Body);
CheckForRedundantIteration(*this, third.get(), Body);

if (Second.get().second &&
    !Diags.isIgnored(diag::warn_comma_operator,
                     Second.get().second->getExprLoc()))
  CommaVisitor(*this).Visit(Second.get().second);

Expr *Third  = third.release().getAs<Expr>();
if (isa<NullStmt>(Body))
  getCurCompoundScope().setHasEmptyLoopBodies();

return new (Context)
    ForStmt(Context, First, Second.get().second, Second.get().first, Third,
            Body, ForLoc, LParenLoc, RParenLoc);
2150}

2152/// In an Objective C collection iteration statement:
2153///   for (x in y)
2154/// x can be an arbitrary l-value expression.  Bind it up as a
2155/// full-expression.
2156StmtResult 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.get();

ExprResult FullExpr = ActOnFinishFullExpr(E, /*DiscardedValue*/ false);
if (FullExpr.isInvalid())
  return StmtError();
return StmtResult(static_cast<Stmt*>(FullExpr.get()));
2167}

2169ExprResult
2170Sema::CheckObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) {
if (!collection)
  return ExprError();

ExprResult result = CorrectDelayedTyposInExpr(collection);
if (!result.isUsable())
  return ExprError();
collection = result.get();

// Bail out early if we've got a type-dependent expression.
if (collection->isTypeDependent()) return collection;

// Perform normal l-value conversion.
result = DefaultFunctionArrayLvalueConversion(collection);
if (result.isInvalid())
  return ExprError();
collection = result.get();

// 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 &&
    (getLangOpts().ObjCAutoRefCount
         ? RequireCompleteType(forLoc, QualType(objectType, 0),
                               diag::err_arc_collection_forward, collection)
         : !isCompleteType(forLoc, QualType(objectType, 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 = nullptr;

  // If there's an interface, look in both the public and private APIs.
  if (iface) {
    method = iface->lookupInstanceMethod(selector);
    if (!method) method = iface->lookupPrivateMethod(selector);
  }

  // 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 collection;
2242}

2244StmtResult
2245Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
                               Stmt *First, Expr *collection,
                               SourceLocation RParenLoc) {
setFunctionHasBranchProtectedScope();

ExprResult CollectionExprResult =
  CheckObjCForCollectionOperand(ForLoc, collection);

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 = dyn_cast<VarDecl>(DS->getSingleDecl());
    if (!D || D->isInvalidDecl())
      return StmtError();

    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_local_variable_decl_in_for));

    // If the type contained 'auto', deduce the 'auto' to 'id'.
    if (FirstType->getContainedAutoType()) {
      OpaqueValueExpr OpaqueId(D->getLocation(), Context.getObjCIdType(),
                               VK_PRValue);
      Expr *DeducedInit = &OpaqueId;
      if (DeduceAutoType(D->getTypeSourceInfo(), DeducedInit, FirstType) ==
              DAR_Failed)
        DiagnoseAutoDeductionFailure(D, DeducedInit);
      if (FirstType.isNull()) {
        D->setInvalidDecl();
        return StmtError();
      }

      D->setType(FirstType);

      if (!inTemplateInstantiation()) {
        SourceLocation Loc =
            D->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
        Diag(Loc, diag::warn_auto_var_is_id)
          << D->getDeclName();
      }
    }

  } else {
    Expr *FirstE = cast<Expr>(First);
    if (!FirstE->isTypeDependent() && !FirstE->isLValue())
      return StmtError(
          Diag(First->getBeginLoc(), diag::err_selector_element_not_lvalue)
          << First->getSourceRange());

    FirstType = static_cast<Expr*>(First)->getType();
    if (FirstType.isConstQualified())
      Diag(ForLoc, diag::err_selector_element_const_type)
        << FirstType << First->getSourceRange();
  }
  if (!FirstType->isDependentType() &&
      !FirstType->isObjCObjectPointerType() &&
      !FirstType->isBlockPointerType())
      return StmtError(Diag(ForLoc, diag::err_selector_element_type)
                         << FirstType << First->getSourceRange());
}

if (CollectionExprResult.isInvalid())
  return StmtError();

CollectionExprResult =
    ActOnFinishFullExpr(CollectionExprResult.get(), /*DiscardedValue*/ false);
if (CollectionExprResult.isInvalid())
  return StmtError();

return new (Context) ObjCForCollectionStmt(First, CollectionExprResult.get(),
                                           nullptr, ForLoc, RParenLoc);
2324}

2326/// Finish building a variable declaration for a for-range statement.
2327/// \return true if an error occurs.
2328static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
                                SourceLocation Loc, int DiagID) {
if (Decl->getType()->isUndeducedType()) {
  ExprResult Res = SemaRef.CorrectDelayedTyposInExpr(Init);
  if (!Res.isUsable()) {
    Decl->setInvalidDecl();
    return true;
  }
  Init = Res.get();
}

// Deduce the type for the iterator variable now rather than leaving it to
// AddInitializerToDecl, so we can produce a more suitable diagnostic.
QualType InitType;
if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) ||
    SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitType) ==
        Sema::DAR_Failed)
  SemaRef.Diag(Loc, DiagID) << Init->getType();
if (InitType.isNull()) {
  Decl->setInvalidDecl();
  return true;
}
Decl->setType(InitType);

// 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);
SemaRef.FinalizeDeclaration(Decl);
SemaRef.CurContext->addHiddenDecl(Decl);
return false;
2363}

2365namespace {
2366// An enum to represent whether something is dealing with a call to begin()
2367// or a call to end() in a range-based for loop.
2368enum BeginEndFunction {
BEF_begin,
BEF_end
2371};

2373/// Produce a note indicating which begin/end function was implicitly called
2374/// by a C++11 for-range statement. This is often not obvious from the code,
2375/// nor from the diagnostics produced when analysing the implicit expressions
2376/// required in a for-range statement.
2377void 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();
2397}

2399/// Build a variable declaration for a for-range statement.
2400VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc,
                            QualType Type, StringRef 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_None);
Decl->setImplicit();
return Decl;
2409}

2411}

2413static bool ObjCEnumerationCollection(Expr *Collection) {
return !Collection->isTypeDependent()
        && Collection->getType()->getAs<ObjCObjectPointerType>() != nullptr;
2416}

2418/// ActOnCXXForRangeStmt - Check and build a C++11 for-range statement.
2419///
2420/// C++11 [stmt.ranged]:
2421///   A range-based for statement is equivalent to
2422///
2423///   {
2424///     auto && __range = range-init;
2425///     for ( auto __begin = begin-expr,
2426///           __end = end-expr;
2427///           __begin != __end;
2428///           ++__begin ) {
2429///       for-range-declaration = *__begin;
2430///       statement
2431///     }
2432///   }
2433///
2434/// The body of the loop is not available yet, since it cannot be analysed until
2435/// we have determined the type of the for-range-declaration.
2436StmtResult Sema::ActOnCXXForRangeStmt(Scope *S, SourceLocation ForLoc,
                                    SourceLocation CoawaitLoc, Stmt *InitStmt,
                                    Stmt *First, SourceLocation ColonLoc,
                                    Expr *Range, SourceLocation RParenLoc,
                                    BuildForRangeKind Kind) {
if (!First)
1
Assuming 'First' is non-null→
  return StmtError();

if (Range && ObjCEnumerationCollection(Range)) {
2
←
Assuming 'Range' is null→
  // FIXME: Support init-statements in Objective-C++20 ranged for statement.
  if (InitStmt)
    return Diag(InitStmt->getBeginLoc(), diag::err_objc_for_range_init_stmt)
               << InitStmt->getSourceRange();
  return ActOnObjCForCollectionStmt(ForLoc, First, Range, RParenLoc);
}

DeclStmt *DS = dyn_cast<DeclStmt>(First);
3
←
Assuming 'First' is not a 'DeclStmt'→
4
←
'DS' initialized to a null pointer value→
assert(DS && "first part of for range not a decl stmt")(static_cast<void> (0));

if (!DS->isSingleDecl()) {
5
←
Called C++ object pointer is null
  Diag(DS->getBeginLoc(), diag::err_type_defined_in_for_range);
  return StmtError();
}

// This function is responsible for attaching an initializer to LoopVar. We
// must call ActOnInitializerError if we fail to do so.
Decl *LoopVar = DS->getSingleDecl();
if (LoopVar->isInvalidDecl() || !Range ||
    DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) {
  ActOnInitializerError(LoopVar);
  return StmtError();
}

// Build the coroutine state immediately and not later during template
// instantiation
if (!CoawaitLoc.isInvalid()) {
  if (!ActOnCoroutineBodyStart(S, CoawaitLoc, "co_await")) {
    ActOnInitializerError(LoopVar);
    return StmtError();
  }
}

// Build  auto && __range = range-init
// Divide by 2, since the variables are in the inner scope (loop body).
const auto DepthStr = std::to_string(S->getDepth() / 2);
SourceLocation RangeLoc = Range->getBeginLoc();
VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc,
                                         Context.getAutoRRefDeductType(),
                                         std::string("__range") + DepthStr);
if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc,
                          diag::err_for_range_deduction_failure)) {
  ActOnInitializerError(LoopVar);
  return StmtError();
}

// Claim the type doesn't contain auto: we've already done the checking.
DeclGroupPtrTy RangeGroup =
    BuildDeclaratorGroup(MutableArrayRef<Decl *>((Decl **)&RangeVar, 1));
StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc);
if (RangeDecl.isInvalid()) {
  ActOnInitializerError(LoopVar);
  return StmtError();
}

StmtResult R = BuildCXXForRangeStmt(
    ForLoc, CoawaitLoc, InitStmt, ColonLoc, RangeDecl.get(),
    /*BeginStmt=*/nullptr, /*EndStmt=*/nullptr,
    /*Cond=*/nullptr, /*Inc=*/nullptr, DS, RParenLoc, Kind);
if (R.isInvalid()) {
  ActOnInitializerError(LoopVar);
  return StmtError();
}

return R;
2510}

2512/// Create the initialization, compare, and increment steps for
2513/// the range-based for loop expression.
2514/// This function does not handle array-based for loops,
2515/// which are created in Sema::BuildCXXForRangeStmt.
2516///
2517/// \returns a ForRangeStatus indicating success or what kind of error occurred.
2518/// BeginExpr and EndExpr are set and FRS_Success is returned on success;
2519/// CandidateSet and BEF are set and some non-success value is returned on
2520/// failure.
2521static Sema::ForRangeStatus
2522BuildNonArrayForRange(Sema &SemaRef, Expr *BeginRange, Expr *EndRange,
                    QualType RangeType, VarDecl *BeginVar, VarDecl *EndVar,
                    SourceLocation ColonLoc, SourceLocation CoawaitLoc,
                    OverloadCandidateSet *CandidateSet, ExprResult *BeginExpr,
                    ExprResult *EndExpr, BeginEndFunction *BEF) {
DeclarationNameInfo BeginNameInfo(
    &SemaRef.PP.getIdentifierTable().get("begin"), ColonLoc);
DeclarationNameInfo EndNameInfo(&SemaRef.PP.getIdentifierTable().get("end"),
                                ColonLoc);

LookupResult BeginMemberLookup(SemaRef, BeginNameInfo,
                               Sema::LookupMemberName);
LookupResult EndMemberLookup(SemaRef, EndNameInfo, Sema::LookupMemberName);

auto BuildBegin = [&] {
  *BEF = BEF_begin;
  Sema::ForRangeStatus RangeStatus =
      SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, BeginNameInfo,
                                        BeginMemberLookup, CandidateSet,
                                        BeginRange, BeginExpr);

  if (RangeStatus != Sema::FRS_Success) {
    if (RangeStatus == Sema::FRS_DiagnosticIssued)
      SemaRef.Diag(BeginRange->getBeginLoc(), diag::note_in_for_range)
          << ColonLoc << BEF_begin << BeginRange->getType();
    return RangeStatus;
  }
  if (!CoawaitLoc.isInvalid()) {
    // FIXME: getCurScope() should not be used during template instantiation.
    // We should pick up the set of unqualified lookup results for operator
    // co_await during the initial parse.
    *BeginExpr = SemaRef.ActOnCoawaitExpr(SemaRef.getCurScope(), ColonLoc,
                                          BeginExpr->get());
    if (BeginExpr->isInvalid())
      return Sema::FRS_DiagnosticIssued;
  }
  if (FinishForRangeVarDecl(SemaRef, BeginVar, BeginExpr->get(), ColonLoc,
                            diag::err_for_range_iter_deduction_failure)) {
    NoteForRangeBeginEndFunction(SemaRef, BeginExpr->get(), *BEF);
    return Sema::FRS_DiagnosticIssued;
  }
  return Sema::FRS_Success;
};

auto BuildEnd = [&] {
  *BEF = BEF_end;
  Sema::ForRangeStatus RangeStatus =
      SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, EndNameInfo,
                                        EndMemberLookup, CandidateSet,
                                        EndRange, EndExpr);
  if (RangeStatus != Sema::FRS_Success) {
    if (RangeStatus == Sema::FRS_DiagnosticIssued)
      SemaRef.Diag(EndRange->getBeginLoc(), diag::note_in_for_range)
          << ColonLoc << BEF_end << EndRange->getType();
    return RangeStatus;
  }
  if (FinishForRangeVarDecl(SemaRef, EndVar, EndExpr->get(), ColonLoc,
                            diag::err_for_range_iter_deduction_failure)) {
    NoteForRangeBeginEndFunction(SemaRef, EndExpr->get(), *BEF);
    return Sema::FRS_DiagnosticIssued;
  }
  return Sema::FRS_Success;
};

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;
  SemaRef.LookupQualifiedName(BeginMemberLookup, D);
  if (BeginMemberLookup.isAmbiguous())
    return Sema::FRS_DiagnosticIssued;

  SemaRef.LookupQualifiedName(EndMemberLookup, D);
  if (EndMemberLookup.isAmbiguous())
    return Sema::FRS_DiagnosticIssued;

  if (BeginMemberLookup.empty() != EndMemberLookup.empty()) {
    // Look up the non-member form of the member we didn't find, first.
    // This way we prefer a "no viable 'end'" diagnostic over a "i found
    // a 'begin' but ignored it because there was no member 'end'"
    // diagnostic.
    auto BuildNonmember = [&](
        BeginEndFunction BEFFound, LookupResult &Found,
        llvm::function_ref<Sema::ForRangeStatus()> BuildFound,
        llvm::function_ref<Sema::ForRangeStatus()> BuildNotFound) {
      LookupResult OldFound = std::move(Found);
      Found.clear();

      if (Sema::ForRangeStatus Result = BuildNotFound())
        return Result;

      switch (BuildFound()) {
      case Sema::FRS_Success:
        return Sema::FRS_Success;

      case Sema::FRS_NoViableFunction:
        CandidateSet->NoteCandidates(
            PartialDiagnosticAt(BeginRange->getBeginLoc(),
                                SemaRef.PDiag(diag::err_for_range_invalid)
                                    << BeginRange->getType() << BEFFound),
            SemaRef, OCD_AllCandidates, BeginRange);
        LLVM_FALLTHROUGH[[gnu::fallthrough]];

      case Sema::FRS_DiagnosticIssued:
        for (NamedDecl *D : OldFound) {
          SemaRef.Diag(D->getLocation(),
                       diag::note_for_range_member_begin_end_ignored)
              << BeginRange->getType() << BEFFound;
        }
        return Sema::FRS_DiagnosticIssued;
      }
      llvm_unreachable("unexpected ForRangeStatus")__builtin_unreachable();
    };
    if (BeginMemberLookup.empty())
      return BuildNonmember(BEF_end, EndMemberLookup, BuildEnd, BuildBegin);
    return BuildNonmember(BEF_begin, BeginMemberLookup, BuildBegin, BuildEnd);
  }
} 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.
}

if (Sema::ForRangeStatus Result = BuildBegin())
  return Result;
return BuildEnd();
2651}

2653/// Speculatively attempt to dereference an invalid range expression.
2654/// If the attempt fails, this function will return a valid, null StmtResult
2655/// and emit no diagnostics.
2656static StmtResult RebuildForRangeWithDereference(Sema &SemaRef, Scope *S,
                                               SourceLocation ForLoc,
                                               SourceLocation CoawaitLoc,
                                               Stmt *InitStmt,
                                               Stmt *LoopVarDecl,
                                               SourceLocation ColonLoc,
                                               Expr *Range,
                                               SourceLocation RangeLoc,
                                               SourceLocation RParenLoc) {
// Determine whether we can rebuild the for-range statement with a
// dereferenced range expression.
ExprResult AdjustedRange;
{
  Sema::SFINAETrap Trap(SemaRef);

  AdjustedRange = SemaRef.BuildUnaryOp(S, RangeLoc, UO_Deref, Range);
  if (AdjustedRange.isInvalid())
    return StmtResult();

  StmtResult SR = SemaRef.ActOnCXXForRangeStmt(
      S, ForLoc, CoawaitLoc, InitStmt, LoopVarDecl, ColonLoc,
      AdjustedRange.get(), RParenLoc, Sema::BFRK_Check);
  if (SR.isInvalid())
    return StmtResult();
}

// The attempt to dereference worked well enough that it could produce a valid
// loop. Produce a fixit, and rebuild the loop with diagnostics enabled, in
// case there are any other (non-fatal) problems with it.
SemaRef.Diag(RangeLoc, diag::err_for_range_dereference)
  << Range->getType() << FixItHint::CreateInsertion(RangeLoc, "*");
return SemaRef.ActOnCXXForRangeStmt(
    S, ForLoc, CoawaitLoc, InitStmt, LoopVarDecl, ColonLoc,
    AdjustedRange.get(), RParenLoc, Sema::BFRK_Rebuild);
2690}

2692/// BuildCXXForRangeStmt - Build or instantiate a C++11 for-range statement.
2693StmtResult Sema::BuildCXXForRangeStmt(SourceLocation ForLoc,
                                    SourceLocation CoawaitLoc, Stmt *InitStmt,
                                    SourceLocation ColonLoc, Stmt *RangeDecl,
                                    Stmt *Begin, Stmt *End, Expr *Cond,
                                    Expr *Inc, Stmt *LoopVarDecl,
                                    SourceLocation RParenLoc,
                                    BuildForRangeKind Kind) {
// FIXME: This should not be used during template instantiation. We should
// pick up the set of unqualified lookup results for the != and + operators
// in the initial parse.
//
// Testcase (accepts-invalid):
//   template<typename T> void f() { for (auto x : T()) {} }
//   namespace N { struct X { X begin(); X end(); int operator*(); }; }
//   bool operator!=(N::X, N::X); void operator++(N::X);
//   void g() { f<N::X>(); }
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 BeginDeclStmt = Begin;
StmtResult EndDeclStmt = End;
ExprResult NotEqExpr = Cond, IncrExpr = Inc;

if (RangeVarType->isDependentType()) {
  // The range is implicitly used as a placeholder when it is dependent.
  RangeVar->markUsed(Context);

  // Deduce any 'auto's in the loop variable as 'DependentTy'. We'll fill
  // them in properly when we instantiate the loop.
  if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
    if (auto *DD = dyn_cast<DecompositionDecl>(LoopVar))
      for (auto *Binding : DD->bindings())
        Binding->setType(Context.DependentTy);
    LoopVar->setType(SubstAutoType(LoopVar->getType(), Context.DependentTy));
  }
} else if (!BeginDeclStmt.get()) {
  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,
                          diag::err_for_range_incomplete_type))
    return StmtError();

  // Build auto __begin = begin-expr, __end = end-expr.
  // Divide by 2, since the variables are in the inner scope (loop body).
  const auto DepthStr = std::to_string(S->getDepth() / 2);
  VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
                                           std::string("__begin") + DepthStr);
  VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
                                         std::string("__end") + DepthStr);

  // 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 (!CoawaitLoc.isInvalid()) {
      BeginExpr = ActOnCoawaitExpr(S, ColonLoc, BeginExpr.get());
      if (BeginExpr.isInvalid())
        return StmtError();
    }
    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 = IntegerLiteral::Create(
          Context, CAT->getSize(), Context.getPointerDiffType(), RangeLoc);
    else if (const VariableArrayType *VAT =
             dyn_cast<VariableArrayType>(UnqAT)) {
      // For a variably modified type we can't just use the expression within
      // the array bounds, since we don't want that to be re-evaluated here.
      // Rather, we need to determine what it was when the array was first
      // created - so we resort to using sizeof(vla)/sizeof(element).
      // For e.g.
      //  void f(int b) {
      //    int vla[b];
      //    b = -1;   <-- This should not affect the num of iterations below
      //    for (int &c : vla) { .. }
      //  }

      // FIXME: This results in codegen generating IR that recalculates the
      // run-time number of elements (as opposed to just using the IR Value
      // that corresponds to the run-time value of each bound that was
      // generated when the array was created.) If this proves too embarrassing
      // even for unoptimized IR, consider passing a magic-value/cookie to
      // codegen that then knows to simply use that initial llvm::Value (that
      // corresponds to the bound at time of array creation) within
      // getelementptr.  But be prepared to pay the price of increasing a
      // customized form of coupling between the two components - which  could
      // be hard to maintain as the codebase evolves.

      ExprResult SizeOfVLAExprR = ActOnUnaryExprOrTypeTraitExpr(
          EndVar->getLocation(), UETT_SizeOf,
          /*IsType=*/true,
          CreateParsedType(VAT->desugar(), Context.getTrivialTypeSourceInfo(
                                               VAT->desugar(), RangeLoc))
              .getAsOpaquePtr(),
          EndVar->getSourceRange());
      if (SizeOfVLAExprR.isInvalid())
        return StmtError();

      ExprResult SizeOfEachElementExprR = ActOnUnaryExprOrTypeTraitExpr(
          EndVar->getLocation(), UETT_SizeOf,
          /*IsType=*/true,
          CreateParsedType(VAT->desugar(),
                           Context.getTrivialTypeSourceInfo(
                               VAT->getElementType(), RangeLoc))
              .getAsOpaquePtr(),
          EndVar->getSourceRange());
      if (SizeOfEachElementExprR.isInvalid())
        return StmtError();

      BoundExpr =
          ActOnBinOp(S, EndVar->getLocation(), tok::slash,
                     SizeOfVLAExprR.get(), SizeOfEachElementExprR.get());
      if (BoundExpr.isInvalid())
        return StmtError();

    } 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")__builtin_unreachable();
    }

    // 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 {
    OverloadCandidateSet CandidateSet(RangeLoc,
                                      OverloadCandidateSet::CSK_Normal);
    BeginEndFunction BEFFailure;
    ForRangeStatus RangeStatus = BuildNonArrayForRange(
        *this, BeginRangeRef.get(), EndRangeRef.get(), RangeType, BeginVar,
        EndVar, ColonLoc, CoawaitLoc, &CandidateSet, &BeginExpr, &EndExpr,
        &BEFFailure);

    if (Kind == BFRK_Build && RangeStatus == FRS_NoViableFunction &&
        BEFFailure == BEF_begin) {
      // If the range is being built from an array parameter, emit a
      // a diagnostic that it is being treated as a pointer.
      if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Range)) {
        if (ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
          QualType ArrayTy = PVD->getOriginalType();
          QualType PointerTy = PVD->getType();
          if (PointerTy->isPointerType() && ArrayTy->isArrayType()) {
            Diag(Range->getBeginLoc(), diag::err_range_on_array_parameter)
                << RangeLoc << PVD << ArrayTy << PointerTy;
            Diag(PVD->getLocation(), diag::note_declared_at);
            return StmtError();
          }
        }
      }

      // If building the range failed, try dereferencing the range expression
      // unless a diagnostic was issued or the end function is problematic.
      StmtResult SR = RebuildForRangeWithDereference(*this, S, ForLoc,
                                                     CoawaitLoc, InitStmt,
                                                     LoopVarDecl, ColonLoc,
                                                     Range, RangeLoc,
                                                     RParenLoc);
      if (SR.isInvalid() || SR.isUsable())
        return SR;
    }

    // Otherwise, emit diagnostics if we haven't already.
    if (RangeStatus == FRS_NoViableFunction) {
      Expr *Range = BEFFailure ? EndRangeRef.get() : BeginRangeRef.get();
      CandidateSet.NoteCandidates(
          PartialDiagnosticAt(Range->getBeginLoc(),
                              PDiag(diag::err_for_range_invalid)
                                  << RangeLoc << Range->getType()
                                  << BEFFailure),
          *this, OCD_AllCandidates, Range);
    }
    // Return an error if no fix was discovered.
    if (RangeStatus != FRS_Success)
      return StmtError();
  }

  assert(!BeginExpr.isInvalid() && !EndExpr.isInvalid() &&(static_cast<void> (0))
         "invalid range expression in for loop")(static_cast<void> (0));

  // C++11 [dcl.spec.auto]p7: BeginType and EndType must be the same.
  // C++1z removes this restriction.
  QualType BeginType = BeginVar->getType(), EndType = EndVar->getType();
  if (!Context.hasSameType(BeginType, EndType)) {
    Diag(RangeLoc, getLangOpts().CPlusPlus17
                       ? diag::warn_for_range_begin_end_types_differ
                       : diag::ext_for_range_begin_end_types_differ)
        << BeginType << EndType;
    NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
    NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
  }

  BeginDeclStmt =
      ActOnDeclStmt(ConvertDeclToDeclGroup(BeginVar), ColonLoc, ColonLoc);
  EndDeclStmt =
      ActOnDeclStmt(ConvertDeclToDeclGroup(EndVar), 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());
  if (!NotEqExpr.isInvalid())
    NotEqExpr = CheckBooleanCondition(ColonLoc, NotEqExpr.get());
  if (!NotEqExpr.isInvalid())
    NotEqExpr =
        ActOnFinishFullExpr(NotEqExpr.get(), /*DiscardedValue*/ false);
  if (NotEqExpr.isInvalid()) {
    Diag(RangeLoc, diag::note_for_range_invalid_iterator)
      << RangeLoc << 0 << BeginRangeRef.get()->getType();
    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());
  if (!IncrExpr.isInvalid() && CoawaitLoc.isValid())
    // FIXME: getCurScope() should not be used during template instantiation.
    // We should pick up the set of unqualified lookup results for operator
    // co_await during the initial parse.
    IncrExpr = ActOnCoawaitExpr(S, CoawaitLoc, IncrExpr.get());
  if (!IncrExpr.isInvalid())
    IncrExpr = ActOnFinishFullExpr(IncrExpr.get(), /*DiscardedValue*/ false);
  if (IncrExpr.isInvalid()) {
    Diag(RangeLoc, diag::note_for_range_invalid_iterator)
      << RangeLoc << 2 << BeginRangeRef.get()->getType() ;
    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()) {
    Diag(RangeLoc, diag::note_for_range_invalid_iterator)
      << RangeLoc << 1 << BeginRangeRef.get()->getType();
    NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
    return StmtError();
  }

  // Attach  *__begin  as initializer for VD. Don't touch it if we're just
  // trying to determine whether this would be a valid range.
  if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
    AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false);
    if (LoopVar->isInvalidDecl() ||
        (LoopVar->getInit() && LoopVar->getInit()->containsErrors()))
      NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
  }
}

// Don't bother to actually allocate the result if we're just trying to
// determine whether it would be valid.
if (Kind == BFRK_Check)
  return StmtResult();

// In OpenMP loop region loop control variable must be private. Perform
// analysis of first part (if any).
if (getLangOpts().OpenMP >= 50 && BeginDeclStmt.isUsable())
  ActOnOpenMPLoopInitialization(ForLoc, BeginDeclStmt.get());

return new (Context) CXXForRangeStmt(
    InitStmt, RangeDS, cast_or_null<DeclStmt>(BeginDeclStmt.get()),
    cast_or_null<DeclStmt>(EndDeclStmt.get()), NotEqExpr.get(),
    IncrExpr.get(), LoopVarDS, /*Body=*/nullptr, ForLoc, CoawaitLoc,
    ColonLoc, RParenLoc);
3020}

3022/// FinishObjCForCollectionStmt - Attach the body to a objective-C foreach
3023/// statement.
3024StmtResult Sema::FinishObjCForCollectionStmt(Stmt *S, Stmt *B) {
if (!S || !B)
  return StmtError();
ObjCForCollectionStmt * ForStmt = cast<ObjCForCollectionStmt>(S);

ForStmt->setBody(B);
return S;
3031}

3033// Warn when the loop variable is a const reference that creates a copy.
3034// Suggest using the non-reference type for copies.  If a copy can be prevented
3035// suggest the const reference type that would do so.
3036// For instance, given "for (const &Foo : Range)", suggest
3037// "for (const Foo : Range)" to denote a copy is made for the loop.  If
3038// possible, also suggest "for (const &Bar : Range)" if this type prevents
3039// the copy altogether.
3040static void DiagnoseForRangeReferenceVariableCopies(Sema &SemaRef,
                                                  const VarDecl *VD,
                                                  QualType RangeInitType) {
const Expr *InitExpr = VD->getInit();
if (!InitExpr)
  return;

QualType VariableType = VD->getType();

if (auto Cleanups = dyn_cast<ExprWithCleanups>(InitExpr))
  if (!Cleanups->cleanupsHaveSideEffects())
    InitExpr = Cleanups->getSubExpr();

const MaterializeTemporaryExpr *MTE =
    dyn_cast<MaterializeTemporaryExpr>(InitExpr);

// No copy made.
if (!MTE)
  return;

const Expr *E = MTE->getSubExpr()->IgnoreImpCasts();

// Searching for either UnaryOperator for dereference of a pointer or
// CXXOperatorCallExpr for handling iterators.
while (!isa<CXXOperatorCallExpr>(E) && !isa<UnaryOperator>(E)) {
  if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(E)) {
    E = CCE->getArg(0);
  } else if (const CXXMemberCallExpr *Call = dyn_cast<CXXMemberCallExpr>(E)) {
    const MemberExpr *ME = cast<MemberExpr>(Call->getCallee());
    E = ME->getBase();
  } else {
    const MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(E);
    E = MTE->getSubExpr();
  }
  E = E->IgnoreImpCasts();
}

QualType ReferenceReturnType;
if (isa<UnaryOperator>(E)) {
  ReferenceReturnType = SemaRef.Context.getLValueReferenceType(E->getType());
} else {
  const CXXOperatorCallExpr *Call = cast<CXXOperatorCallExpr>(E);
  const FunctionDecl *FD = Call->getDirectCallee();
  QualType ReturnType = FD->getReturnType();
  if (ReturnType->isReferenceType())
    ReferenceReturnType = ReturnType;
}

if (!ReferenceReturnType.isNull()) {
  // Loop variable creates a temporary.  Suggest either to go with
  // non-reference loop variable to indicate a copy is made, or
  // the correct type to bind a const reference.
  SemaRef.Diag(VD->getLocation(),
               diag::warn_for_range_const_ref_binds_temp_built_from_ref)
      << VD << VariableType << ReferenceReturnType;
  QualType NonReferenceType = VariableType.getNonReferenceType();
  NonReferenceType.removeLocalConst();
  QualType NewReferenceType =
      SemaRef.Context.getLValueReferenceType(E->getType().withConst());
  SemaRef.Diag(VD->getBeginLoc(), diag::note_use_type_or_non_reference)
      << NonReferenceType << NewReferenceType << VD->getSourceRange()
      << FixItHint::CreateRemoval(VD->getTypeSpecEndLoc());
} else if (!VariableType->isRValueReferenceType()) {
  // The range always returns a copy, so a temporary is always created.
  // Suggest removing the reference from the loop variable.
  // If the type is a rvalue reference do not warn since that changes the
  // semantic of the code.
  SemaRef.Diag(VD->getLocation(), diag::warn_for_range_ref_binds_ret_temp)
      << VD << RangeInitType;
  QualType NonReferenceType = VariableType.getNonReferenceType();
  NonReferenceType.removeLocalConst();
  SemaRef.Diag(VD->getBeginLoc(), diag::note_use_non_reference_type)
      << NonReferenceType << VD->getSourceRange()
      << FixItHint::CreateRemoval(VD->getTypeSpecEndLoc());
}
3115}

3117/// Determines whether the @p VariableType's declaration is a record with the
3118/// clang::trivial_abi attribute.
3119static bool hasTrivialABIAttr(QualType VariableType) {
if (CXXRecordDecl *RD = VariableType->getAsCXXRecordDecl())
  return RD->hasAttr<TrivialABIAttr>();

return false;
3124}

3126// Warns when the loop variable can be changed to a reference type to
3127// prevent a copy.  For instance, if given "for (const Foo x : Range)" suggest
3128// "for (const Foo &x : Range)" if this form does not make a copy.
3129static void DiagnoseForRangeConstVariableCopies(Sema &SemaRef,
                                              const VarDecl *VD) {
const Expr *InitExpr = VD->getInit();
if (!InitExpr)
  return;

QualType VariableType = VD->getType();

if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(InitExpr)) {
  if (!CE->getConstructor()->isCopyConstructor())
    return;
} else if (const CastExpr *CE = dyn_cast<CastExpr>(InitExpr)) {
  if (CE->getCastKind() != CK_LValueToRValue)
    return;
} else {
  return;
}

// Small trivially copyable types are cheap to copy. Do not emit the
// diagnostic for these instances. 64 bytes is a common size of a cache line.
// (The function `getTypeSize` returns the size in bits.)
ASTContext &Ctx = SemaRef.Context;
if (Ctx.getTypeSize(VariableType) <= 64 * 8 &&
    (VariableType.isTriviallyCopyableType(Ctx) ||
     hasTrivialABIAttr(VariableType)))
  return;

// Suggest changing from a const variable to a const reference variable
// if doing so will prevent a copy.
SemaRef.Diag(VD->getLocation(), diag::warn_for_range_copy)
    << VD << VariableType;
SemaRef.Diag(VD->getBeginLoc(), diag::note_use_reference_type)
    << SemaRef.Context.getLValueReferenceType(VariableType)
    << VD->getSourceRange()
    << FixItHint::CreateInsertion(VD->getLocation(), "&");
3164}

3166/// DiagnoseForRangeVariableCopies - Diagnose three cases and fixes for them.
3167/// 1) for (const foo &x : foos) where foos only returns a copy.  Suggest
3168///    using "const foo x" to show that a copy is made
3169/// 2) for (const bar &x : foos) where bar is a temporary initialized by bar.
3170///    Suggest either "const bar x" to keep the copying or "const foo& x" to
3171///    prevent the copy.
3172/// 3) for (const foo x : foos) where x is constructed from a reference foo.
3173///    Suggest "const foo &x" to prevent the copy.
3174static void DiagnoseForRangeVariableCopies(Sema &SemaRef,
                                         const CXXForRangeStmt *ForStmt) {
if (SemaRef.inTemplateInstantiation())
  return;

if (SemaRef.Diags.isIgnored(
        diag::warn_for_range_const_ref_binds_temp_built_from_ref,
        ForStmt->getBeginLoc()) &&
    SemaRef.Diags.isIgnored(diag::warn_for_range_ref_binds_ret_temp,
                            ForStmt->getBeginLoc()) &&
    SemaRef.Diags.isIgnored(diag::warn_for_range_copy,
                            ForStmt->getBeginLoc())) {
  return;
}

const VarDecl *VD = ForStmt->getLoopVariable();
if (!VD)
  return;

QualType VariableType = VD->getType();

if (VariableType->isIncompleteType())
  return;

const Expr *InitExpr = VD->getInit();
if (!InitExpr)
  return;

if (InitExpr->getExprLoc().isMacroID())
  return;

if (VariableType->isReferenceType()) {
  DiagnoseForRangeReferenceVariableCopies(SemaRef, VD,
                                          ForStmt->getRangeInit()->getType());
} else if (VariableType.isConstQualified()) {
  DiagnoseForRangeConstVariableCopies(SemaRef, VD);
}
3211}

3213/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement.
3214/// This is a separate step from ActOnCXXForRangeStmt because analysis of the
3215/// body cannot be performed until after the type of the range variable is
3216/// determined.
3217StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) {
if (!S || !B)
  return StmtError();

if (isa<ObjCForCollectionStmt>(S))
  return FinishObjCForCollectionStmt(S, B);

CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S);
ForStmt->setBody(B);

DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B,
                      diag::warn_empty_range_based_for_body);

DiagnoseForRangeVariableCopies(*this, ForStmt);

return S;
3233}

3235StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc,
                             SourceLocation LabelLoc,
                             LabelDecl *TheDecl) {
setFunctionHasBranchIntoScope();
TheDecl->markUsed(Context);
return new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc);
3241}

3243StmtResult
3244Sema::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 = E;
  AssignConvertType ConvTy =
    CheckSingleAssignmentConstraints(DestTy, ExprRes);
  if (ExprRes.isInvalid())
    return StmtError();
  E = ExprRes.get();
  if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing))
    return StmtError();
}

ExprResult ExprRes = ActOnFinishFullExpr(E, /*DiscardedValue*/ false);
if (ExprRes.isInvalid())
  return StmtError();
E = ExprRes.get();

setFunctionHasIndirectGoto();

return new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E);
3268}

3270static void CheckJumpOutOfSEHFinally(Sema &S, SourceLocation Loc,
                                   const Scope &DestScope) {
if (!S.CurrentSEHFinally.empty() &&
    DestScope.Contains(*S.CurrentSEHFinally.back())) {
  S.Diag(Loc, diag::warn_jump_out_of_seh_finally);
}
3276}

3278StmtResult
3279Sema::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));
}
if (S->getFlags() & Scope::ConditionVarScope) {
  // We cannot 'continue;' from within a statement expression in the
  // initializer of a condition variable because we would jump past the
  // initialization of that variable.
  return StmtError(Diag(ContinueLoc, diag::err_continue_from_cond_var_init));
}
CheckJumpOutOfSEHFinally(*this, ContinueLoc, *S);

return new (Context) ContinueStmt(ContinueLoc);
3294}

3296StmtResult
3297Sema::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));
}
if (S->isOpenMPLoopScope())
  return StmtError(Diag(BreakLoc, diag::err_omp_loop_cannot_use_stmt)
                   << "break");
CheckJumpOutOfSEHFinally(*this, BreakLoc, *S);

return new (Context) BreakStmt(BreakLoc);
3309}

3311/// Determine whether the given expression might be move-eligible or
3312/// copy-elidable in either a (co_)return statement or throw expression,
3313/// without considering function return type, if applicable.
3314///
3315/// \param E The expression being returned from the function or block,
3316/// being thrown, or being co_returned from a coroutine. This expression
3317/// might be modified by the implementation.
3318///
3319/// \param Mode Overrides detection of current language mode
3320/// and uses the rules for C++2b.
3321///
3322/// \returns An aggregate which contains the Candidate and isMoveEligible
3323/// and isCopyElidable methods. If Candidate is non-null, it means
3324/// isMoveEligible() would be true under the most permissive language standard.
3325Sema::NamedReturnInfo Sema::getNamedReturnInfo(Expr *&E,
                                             SimplerImplicitMoveMode Mode) {
if (!E)
  return NamedReturnInfo();
// - in a return statement in a function [where] ...
// ... the expression is the name of a non-volatile automatic object ...
const auto *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens());
if (!DR || DR->refersToEnclosingVariableOrCapture())
  return NamedReturnInfo();
const auto *VD = dyn_cast<VarDecl>(DR->getDecl());
if (!VD)
  return NamedReturnInfo();
NamedReturnInfo Res = getNamedReturnInfo(VD);
if (Res.Candidate && !E->isXValue() &&
    (Mode == SimplerImplicitMoveMode::ForceOn ||
     (Mode != SimplerImplicitMoveMode::ForceOff &&
      getLangOpts().CPlusPlus2b))) {
  E = ImplicitCastExpr::Create(Context, VD->getType().getNonReferenceType(),
                               CK_NoOp, E, nullptr, VK_XValue,
                               FPOptionsOverride());
}
return Res;
3347}

3349/// Determine whether the given NRVO candidate variable is move-eligible or
3350/// copy-elidable, without considering function return type.
3351///
3352/// \param VD The NRVO candidate variable.
3353///
3354/// \returns An aggregate which contains the Candidate and isMoveEligible
3355/// and isCopyElidable methods. If Candidate is non-null, it means
3356/// isMoveEligible() would be true under the most permissive language standard.
3357Sema::NamedReturnInfo Sema::getNamedReturnInfo(const VarDecl *VD) {
NamedReturnInfo Info{VD, NamedReturnInfo::MoveEligibleAndCopyElidable};

// C++20 [class.copy.elision]p3:
// - in a return statement in a function with ...
// (other than a function ... parameter)
if (VD->getKind() == Decl::ParmVar)
  Info.S = NamedReturnInfo::MoveEligible;
else if (VD->getKind() != Decl::Var)
  return NamedReturnInfo();

// (other than ... a catch-clause parameter)
if (VD->isExceptionVariable())
  Info.S = NamedReturnInfo::MoveEligible;

// ...automatic...
if (!VD->hasLocalStorage())
  return NamedReturnInfo();

// We don't want to implicitly move out of a __block variable during a return
// because we cannot assume the variable will no longer be used.
if (VD->hasAttr<BlocksAttr>())
  return NamedReturnInfo();

QualType VDType = VD->getType();
if (VDType->isObjectType()) {
  // C++17 [class.copy.elision]p3:
  // ...non-volatile automatic object...
  if (VDType.isVolatileQualified())
    return NamedReturnInfo();
} else if (VDType->isRValueReferenceType()) {
  // C++20 [class.copy.elision]p3:
  // ...either a non-volatile object or an rvalue reference to a non-volatile
  // object type...
  QualType VDReferencedType = VDType.getNonReferenceType();
  if (VDReferencedType.isVolatileQualified() ||
      !VDReferencedType->isObjectType())
    return NamedReturnInfo();
  Info.S = NamedReturnInfo::MoveEligible;
} else {
  return NamedReturnInfo();
}

// Variables with higher required alignment than their type's ABI
// alignment cannot use NRVO.
if (!VD->hasDependentAlignment() &&
    Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VDType))
  Info.S = NamedReturnInfo::MoveEligible;

return Info;
3407}

3409/// Updates given NamedReturnInfo's move-eligible and
3410/// copy-elidable statuses, considering the function
3411/// return type criteria as applicable to return statements.
3412///
3413/// \param Info The NamedReturnInfo object to update.
3414///
3415/// \param ReturnType This is the return type of the function.
3416/// \returns The copy elision candidate, in case the initial return expression
3417/// was copy elidable, or nullptr otherwise.
3418const VarDecl *Sema::getCopyElisionCandidate(NamedReturnInfo &Info,
                                           QualType ReturnType) {
if (!Info.Candidate)
  return nullptr;

auto invalidNRVO = [&] {
  Info = NamedReturnInfo();
  return nullptr;
};

// If we got a non-deduced auto ReturnType, we are in a dependent context and
// there is no point in allowing copy elision since we won't have it deduced
// by the point the VardDecl is instantiated, which is the last chance we have
// of deciding if the candidate is really copy elidable.
if ((ReturnType->getTypeClass() == Type::TypeClass::Auto &&
     ReturnType->isCanonicalUnqualified()) ||
    ReturnType->isSpecificBuiltinType(BuiltinType::Dependent))
  return invalidNRVO();

if (!ReturnType->isDependentType()) {
  // - in a return statement in a function with ...
  // ... a class return type ...
  if (!ReturnType->isRecordType())
    return invalidNRVO();

  QualType VDType = Info.Candidate->getType();
  // ... the same cv-unqualified type as the function return type ...
  // When considering moving this expression out, allow dissimilar types.
  if (!VDType->isDependentType() &&
      !Context.hasSameUnqualifiedType(ReturnType, VDType))
    Info.S = NamedReturnInfo::MoveEligible;
}
return Info.isCopyElidable() ? Info.Candidate : nullptr;
3451}

3453/// Verify that the initialization sequence that was picked for the
3454/// first overload resolution is permissible under C++98.
3455///
3456/// Reject (possibly converting) contructors not taking an rvalue reference,
3457/// or user conversion operators which are not ref-qualified.
3458static bool
3459VerifyInitializationSequenceCXX98(const Sema &S,
                                const InitializationSequence &Seq) {
const auto *Step = llvm::find_if(Seq.steps(), [](const auto &Step) {
  return Step.Kind == InitializationSequence::SK_ConstructorInitialization ||
         Step.Kind == InitializationSequence::SK_UserConversion;
});
if (Step != Seq.step_end()) {
  const auto *FD = Step->Function.Function;
  if (isa<CXXConstructorDecl>(FD)
          ? !FD->getParamDecl(0)->getType()->isRValueReferenceType()
          : cast<CXXMethodDecl>(FD)->getRefQualifier() == RQ_None)
    return false;
}
return true;
3473}

3475/// Perform the initialization of a potentially-movable value, which
3476/// is the result of return value.
3477///
3478/// This routine implements C++20 [class.copy.elision]p3, which attempts to
3479/// treat returned lvalues as rvalues in certain cases (to prefer move
3480/// construction), then falls back to treating them as lvalues if that failed.
3481ExprResult Sema::PerformMoveOrCopyInitialization(
  const InitializedEntity &Entity, const NamedReturnInfo &NRInfo, Expr *Value,
  bool SupressSimplerImplicitMoves) {
if ((!getLangOpts().CPlusPlus2b || SupressSimplerImplicitMoves) &&
    NRInfo.isMoveEligible()) {
  ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, Value->getType(),
                            CK_NoOp, Value, VK_XValue, FPOptionsOverride());
  Expr *InitExpr = &AsRvalue;
  auto Kind = InitializationKind::CreateCopy(Value->getBeginLoc(),
                                             Value->getBeginLoc());
  InitializationSequence Seq(*this, Entity, Kind, InitExpr);
  auto Res = Seq.getFailedOverloadResult();
  if ((Res == OR_Success || Res == OR_Deleted) &&
      (getLangOpts().CPlusPlus11 ||
       VerifyInitializationSequenceCXX98(*this, Seq))) {
    // Promote "AsRvalue" to the heap, since we now need this
    // expression node to persist.
    Value =
        ImplicitCastExpr::Create(Context, Value->getType(), CK_NoOp, Value,
                                 nullptr, VK_XValue, FPOptionsOverride());
    // Complete type-checking the initialization of the return type
    // using the constructor we found.
    return Seq.Perform(*this, Entity, Kind, Value);
  }
}
// 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.
return PerformCopyInitialization(Entity, SourceLocation(), Value);
3510}

3512/// Determine whether the declared return type of the specified function
3513/// contains 'auto'.
3514static bool hasDeducedReturnType(FunctionDecl *FD) {
const FunctionProtoType *FPT =
    FD->getTypeSourceInfo()->getType()->castAs<FunctionProtoType>();
return FPT->getReturnType()->isUndeducedType();
3518}

3520/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements
3521/// for capturing scopes.
3522///
3523StmtResult Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc,
                                       Expr *RetValExp,
                                       NamedReturnInfo &NRInfo,
                                       bool SupressSimplerImplicitMoves) {
// If this is the first return we've seen, infer the return type.
// [expr.prim.lambda]p4 in C++11; block literals follow the same rules.
CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction());
QualType FnRetType = CurCap->ReturnType;
LambdaScopeInfo *CurLambda = dyn_cast<LambdaScopeInfo>(CurCap);
bool HasDeducedReturnType =
    CurLambda && hasDeducedReturnType(CurLambda->CallOperator);

if (ExprEvalContexts.back().Context ==
        ExpressionEvaluationContext::DiscardedStatement &&
    (HasDeducedReturnType || CurCap->HasImplicitReturnType)) {
  if (RetValExp) {
    ExprResult ER =
        ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
    if (ER.isInvalid())
      return StmtError();
    RetValExp = ER.get();
  }
  return ReturnStmt::Create(Context, ReturnLoc, RetValExp,
                            /* NRVOCandidate=*/nullptr);
}

if (HasDeducedReturnType) {
  FunctionDecl *FD = CurLambda->CallOperator;
  // If we've already decided this lambda is invalid, e.g. because
  // we saw a `return` whose expression had an error, don't keep
  // trying to deduce its return type.
  if (FD->isInvalidDecl())
    return StmtError();
  // In C++1y, the return type may involve 'auto'.
  // FIXME: Blocks might have a return type of 'auto' explicitly specified.
  if (CurCap->ReturnType.isNull())
    CurCap->ReturnType = FD->getReturnType();

  AutoType *AT = CurCap->ReturnType->getContainedAutoType();
  assert(AT && "lost auto type from lambda return type")(static_cast<void> (0));
  if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
    FD->setInvalidDecl();
    // FIXME: preserve the ill-formed return expression.
    return StmtError();
  }
  CurCap->ReturnType = FnRetType = FD->getReturnType();
} else if (CurCap->HasImplicitReturnType) {
  // For blocks/lambdas with implicit return types, we check each return
  // statement individually, and deduce the common return type when the block
  // or lambda is completed.
  // FIXME: Fold this into the 'auto' codepath above.
  if (RetValExp && !isa<InitListExpr>(RetValExp)) {
    ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp);
    if (Result.isInvalid())
      return StmtError();
    RetValExp = Result.get();

    // DR1048: even prior to C++14, we should use the 'auto' deduction rules
    // when deducing a return type for a lambda-expression (or by extension
    // for a block). These rules differ from the stated C++11 rules only in
    // that they remove top-level cv-qualifiers.
    if (!CurContext->isDependentContext())
      FnRetType = RetValExp->getType().getUnqualifiedType();
    else
      FnRetType = CurCap->ReturnType = 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();
    }

    FnRetType = Context.VoidTy;
  }

  // Although we'll properly infer the type of the block once it's completed,
  // make sure we provide a return type now for better error recovery.
  if (CurCap->ReturnType.isNull())
    CurCap->ReturnType = FnRetType;
}
const VarDecl *NRVOCandidate = getCopyElisionCandidate(NRInfo, FnRetType);

if (auto *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) {
  if (CurBlock->FunctionType->castAs<FunctionType>()->getNoReturnAttr()) {
    Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr);
    return StmtError();
  }
} else if (auto *CurRegion = dyn_cast<CapturedRegionScopeInfo>(CurCap)) {
  Diag(ReturnLoc, diag::err_return_in_captured_stmt) << CurRegion->getRegionName();
  return StmtError();
} else {
  assert(CurLambda && "unknown kind of captured scope")(static_cast<void> (0));
  if (CurLambda->CallOperator->getType()
          ->castAs<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.
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 = nullptr;
    }
  }
} 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.
  InitializedEntity Entity = InitializedEntity::InitializeResult(
      ReturnLoc, FnRetType, NRVOCandidate != nullptr);
  ExprResult Res = PerformMoveOrCopyInitialization(
      Entity, NRInfo, RetValExp, SupressSimplerImplicitMoves);
  if (Res.isInvalid()) {
    // FIXME: Cleanup temporaries here, anyway?
    return StmtError();
  }
  RetValExp = Res.get();
  CheckReturnValExpr(RetValExp, FnRetType, ReturnLoc);
}

if (RetValExp) {
  ExprResult ER =
      ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
  if (ER.isInvalid())
    return StmtError();
  RetValExp = ER.get();
}
auto *Result =
    ReturnStmt::Create(Context, ReturnLoc, RetValExp, NRVOCandidate);

// If we need to check for the named return value optimization,
// or if we need to infer the return type,
// save the return statement in our scope for later processing.
if (CurCap->HasImplicitReturnType || NRVOCandidate)
  FunctionScopes.back()->Returns.push_back(Result);

if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
  FunctionScopes.back()->FirstReturnLoc = ReturnLoc;

return Result;
3687}

3689namespace {
3690/// Marks all typedefs in all local classes in a type referenced.
3691///
3692/// In a function like
3693/// auto f() {
3694///   struct S { typedef int a; };
3695///   return S();
3696/// }
3697///
3698/// the local type escapes and could be referenced in some TUs but not in
3699/// others. Pretend that all local typedefs are always referenced, to not warn
3700/// on this. This isn't necessary if f has internal linkage, or the typedef
3701/// is private.
3702class LocalTypedefNameReferencer
  : public RecursiveASTVisitor<LocalTypedefNameReferencer> {
3704public:
LocalTypedefNameReferencer(Sema &S) : S(S) {}
bool VisitRecordType(const RecordType *RT);
3707private:
Sema &S;
3709};
3710bool LocalTypedefNameReferencer::VisitRecordType(const RecordType *RT) {
auto *R = dyn_cast<CXXRecordDecl>(RT->getDecl());
if (!R || !R->isLocalClass() || !R->isLocalClass()->isExternallyVisible() ||
    R->isDependentType())
  return true;
for (auto *TmpD : R->decls())
  if (auto *T = dyn_cast<TypedefNameDecl>(TmpD))
    if (T->getAccess() != AS_private || R->hasFriends())
      S.MarkAnyDeclReferenced(T->getLocation(), T, /*OdrUse=*/false);
return true;
3720}
3721}

3723TypeLoc Sema::getReturnTypeLoc(FunctionDecl *FD) const {
return FD->getTypeSourceInfo()
    ->getTypeLoc()
    .getAsAdjusted<FunctionProtoTypeLoc>()
    .getReturnLoc();
3728}

3730/// Deduce the return type for a function from a returned expression, per
3731/// C++1y [dcl.spec.auto]p6.
3732bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
                                          SourceLocation ReturnLoc,
                                          Expr *&RetExpr,
                                          AutoType *AT) {
// If this is the conversion function for a lambda, we choose to deduce it
// type from the corresponding call operator, not from the synthesized return
// statement within it. See Sema::DeduceReturnType.
if (isLambdaConversionOperator(FD))
  return false;

TypeLoc OrigResultType = getReturnTypeLoc(FD);
QualType Deduced;

if (RetExpr && isa<InitListExpr>(RetExpr)) {
  //  If the deduction is for a return statement and the initializer is
  //  a braced-init-list, the program is ill-formed.
  Diag(RetExpr->getExprLoc(),
       getCurLambda() ? diag::err_lambda_return_init_list
                      : diag::err_auto_fn_return_init_list)
      << RetExpr->getSourceRange();
  return true;
}

if (FD->isDependentContext()) {
  // C++1y [dcl.spec.auto]p12:
  //   Return type deduction [...] occurs when the definition is
  //   instantiated even if the function body contains a return
  //   statement with a non-type-dependent operand.
  assert(AT->isDeduced() && "should have deduced to dependent type")(static_cast<void> (0));
  return false;
}

if (RetExpr) {
  //  Otherwise, [...] deduce a value for U using the rules of template
  //  argument deduction.
  DeduceAutoResult DAR = DeduceAutoType(OrigResultType, RetExpr, Deduced);

  if (DAR == DAR_Failed && !FD->isInvalidDecl())
    Diag(RetExpr->getExprLoc(), diag::err_auto_fn_deduction_failure)
      << OrigResultType.getType() << RetExpr->getType();

  if (DAR != DAR_Succeeded)
    return true;

  // If a local type is part of the returned type, mark its fields as
  // referenced.
  LocalTypedefNameReferencer Referencer(*this);
  Referencer.TraverseType(RetExpr->getType());
} else {
  //  In the case of a return with no operand, the initializer is considered
  //  to be void().
  //
  // Deduction here can only succeed if the return type is exactly 'cv auto'
  // or 'decltype(auto)', so just check for that case directly.
  if (!OrigResultType.getType()->getAs<AutoType>()) {
    Diag(ReturnLoc, diag::err_auto_fn_return_void_but_not_auto)
      << OrigResultType.getType();
    return true;
  }
  // We always deduce U = void in this case.
  Deduced = SubstAutoType(OrigResultType.getType(), Context.VoidTy);
  if (Deduced.isNull())
    return true;
}

// CUDA: Kernel function must have 'void' return type.
if (getLangOpts().CUDA)
  if (FD->hasAttr<CUDAGlobalAttr>() && !Deduced->isVoidType()) {
    Diag(FD->getLocation(), diag::err_kern_type_not_void_return)
        << FD->getType() << FD->getSourceRange();
    return true;
  }

//  If a function with a declared return type that contains a placeholder type
//  has multiple return statements, the return type is deduced for each return
//  statement. [...] if the type deduced is not the same in each deduction,
//  the program is ill-formed.
QualType DeducedT = AT->getDeducedType();
if (!DeducedT.isNull() && !FD->isInvalidDecl()) {
  AutoType *NewAT = Deduced->getContainedAutoType();
  // It is possible that NewAT->getDeducedType() is null. When that happens,
  // we should not crash, instead we ignore this deduction.
  if (NewAT->getDeducedType().isNull())
    return false;

  CanQualType OldDeducedType = Context.getCanonicalFunctionResultType(
                                 DeducedT);
  CanQualType NewDeducedType = Context.getCanonicalFunctionResultType(
                                 NewAT->getDeducedType());
  if (!FD->isDependentContext() && OldDeducedType != NewDeducedType) {
    const LambdaScopeInfo *LambdaSI = getCurLambda();
    if (LambdaSI && LambdaSI->HasImplicitReturnType) {
      Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible)
        << NewAT->getDeducedType() << DeducedT
        << true /*IsLambda*/;
    } else {
      Diag(ReturnLoc, diag::err_auto_fn_different_deductions)
        << (AT->isDecltypeAuto() ? 1 : 0)
        << NewAT->getDeducedType() << DeducedT;
    }
    return true;
  }
} else if (!FD->isInvalidDecl()) {
  // Update all declarations of the function to have the deduced return type.
  Context.adjustDeducedFunctionResultType(FD, Deduced);
}

return false;
3840}

3842StmtResult
3843Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
                    Scope *CurScope) {
// Correct typos, in case the containing function returns 'auto' and
// RetValExp should determine the deduced type.
ExprResult RetVal = CorrectDelayedTyposInExpr(
    RetValExp, nullptr, /*RecoverUncorrectedTypos=*/true);
if (RetVal.isInvalid())
  return StmtError();
StmtResult R = BuildReturnStmt(ReturnLoc, RetVal.get());
if (R.isInvalid() || ExprEvalContexts.back().Context ==
                         ExpressionEvaluationContext::DiscardedStatement)
  return R;

if (VarDecl *VD =
    const_cast<VarDecl*>(cast<ReturnStmt>(R.get())->getNRVOCandidate())) {
  CurScope->addNRVOCandidate(VD);
} else {
  CurScope->setNoNRVO();
}

CheckJumpOutOfSEHFinally(*this, ReturnLoc, *CurScope->getFnParent());

return R;
3866}

3868static bool CheckSimplerImplicitMovesMSVCWorkaround(const Sema &S,
                                                  const Expr *E) {
if (!E || !S.getLangOpts().CPlusPlus2b || !S.getLangOpts().MSVCCompat)
  return false;
const Decl *D = E->getReferencedDeclOfCallee();
if (!D || !S.SourceMgr.isInSystemHeader(D->getLocation()))
  return false;
for (const DeclContext *DC = D->getDeclContext(); DC; DC = DC->getParent()) {
  if (DC->isStdNamespace())
    return true;
}
return false;
3880}

3882StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
// Check for unexpanded parameter packs.
if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp))
  return StmtError();

// HACK: We supress simpler implicit move here in msvc compatibility mode
// just as a temporary work around, as the MSVC STL has issues with
// this change.
bool SupressSimplerImplicitMoves =
    CheckSimplerImplicitMovesMSVCWorkaround(*this, RetValExp);
NamedReturnInfo NRInfo = getNamedReturnInfo(
    RetValExp, SupressSimplerImplicitMoves ? SimplerImplicitMoveMode::ForceOff
                                           : SimplerImplicitMoveMode::Normal);

if (isa<CapturingScopeInfo>(getCurFunction()))
  return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp, NRInfo,
                                 SupressSimplerImplicitMoves);

QualType FnRetType;
QualType RelatedRetType;
const AttrVec *Attrs = nullptr;
bool isObjCMethod = false;

if (const FunctionDecl *FD = getCurFunctionDecl()) {
  FnRetType = FD->getReturnType();
  if (FD->hasAttrs())
    Attrs = &FD->getAttrs();
  if (FD->isNoReturn())
    Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) << FD;
  if (FD->isMain() && RetValExp)
    if (isa<CXXBoolLiteralExpr>(RetValExp))
      Diag(ReturnLoc, diag::warn_main_returns_bool_literal)
          << RetValExp->getSourceRange();
  if (FD->hasAttr<CmseNSEntryAttr>() && RetValExp) {
    if (const auto *RT = dyn_cast<RecordType>(FnRetType.getCanonicalType())) {
      if (RT->getDecl()->isOrContainsUnion())
        Diag(RetValExp->getBeginLoc(), diag::warn_cmse_nonsecure_union) << 1;
    }
  }
} else if (ObjCMethodDecl *MD = getCurMethodDecl()) {
  FnRetType = MD->getReturnType();
  isObjCMethod = true;
  if (MD->hasAttrs())
    Attrs = &MD->getAttrs();
  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();

// C++1z: discarded return statements are not considered when deducing a
// return type.
if (ExprEvalContexts.back().Context ==
        ExpressionEvaluationContext::DiscardedStatement &&
    FnRetType->getContainedAutoType()) {
  if (RetValExp) {
    ExprResult ER =
        ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
    if (ER.isInvalid())
      return StmtError();
    RetValExp = ER.get();
  }
  return ReturnStmt::Create(Context, ReturnLoc, RetValExp,
                            /* NRVOCandidate=*/nullptr);
}

// FIXME: Add a flag to the ScopeInfo to indicate whether we're performing
// deduction.
if (getLangOpts().CPlusPlus14) {
  if (AutoType *AT = FnRetType->getContainedAutoType()) {
    FunctionDecl *FD = cast<FunctionDecl>(CurContext);
    // If we've already decided this function is invalid, e.g. because
    // we saw a `return` whose expression had an error, don't keep
    // trying to deduce its return type.
    if (FD->isInvalidDecl())
      return StmtError();
    if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
      FD->setInvalidDecl();
      return StmtError();
    } else {
      FnRetType = FD->getReturnType();
    }
  }
}
const VarDecl *NRVOCandidate = getCopyElisionCandidate(NRInfo, FnRetType);

bool HasDependentReturnType = FnRetType->isDependentType();

ReturnStmt *Result = nullptr;
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 << FunctionKind << RetValExp->getSourceRange();

      // Drop the expression.
      RetValExp = nullptr;
    } else if (!RetValExp->isTypeDependent()) {
      // C99 6.8.6.4p1 (ext_ since GCC warns)
      unsigned D = diag::ext_return_has_expr;
      if (RetValExp->getType()->isVoidType()) {
        NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
        if (isa<CXXConstructorDecl>(CurDecl) ||
            isa<CXXDestructorDecl>(CurDecl))
          D = diag::err_ctor_dtor_returns_void;
        else
          D = diag::ext_return_has_void_expr;
      }
      else {
        ExprResult Result = RetValExp;
        Result = IgnoredValueConversions(Result.get());
        if (Result.isInvalid())
          return StmtError();
        RetValExp = Result.get();
        RetValExp = ImpCastExprToType(RetValExp,
                                      Context.VoidTy, CK_ToVoid).get();
      }
      // return of void in constructor/destructor is illegal in C++.
      if (D == diag::err_ctor_dtor_returns_void) {
        NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
        Diag(ReturnLoc, D) << CurDecl << isa<CXXDestructorDecl>(CurDecl)
                           << RetValExp->getSourceRange();
      }
      // return (some void expression); is legal in C++.
      else 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 << FunctionKind << RetValExp->getSourceRange();
      }
    }

    if (RetValExp) {
      ExprResult ER =
          ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
      if (ER.isInvalid())
        return StmtError();
      RetValExp = ER.get();
    }
  }

  Result = ReturnStmt::Create(Context, ReturnLoc, RetValExp,
                              /* NRVOCandidate=*/nullptr);
} else if (!RetValExp && !HasDependentReturnType) {
  FunctionDecl *FD = getCurFunctionDecl();

  if (getLangOpts().CPlusPlus11 && FD && FD->isConstexpr()) {
    // C++11 [stmt.return]p2
    Diag(ReturnLoc, diag::err_constexpr_return_missing_expr)
        << FD << FD->isConsteval();
    FD->setInvalidDecl();
  } else {
    // C99 6.8.6.4p1 (ext_ since GCC warns)
    // C90 6.6.6.4p4
    unsigned DiagID = getLangOpts().C99 ? diag::ext_return_missing_expr
                                        : diag::warn_return_missing_expr;
    // Note that at this point one of getCurFunctionDecl() or
    // getCurMethodDecl() must be non-null (see above).
    assert((getCurFunctionDecl() || getCurMethodDecl()) &&(static_cast<void> (0))
           "Not in a FunctionDecl or ObjCMethodDecl?")(static_cast<void> (0));
    bool IsMethod = FD == nullptr;
    const NamedDecl *ND =
        IsMethod ? cast<NamedDecl>(getCurMethodDecl()) : cast<NamedDecl>(FD);
    Diag(ReturnLoc, DiagID) << ND << IsMethod;
  }

  Result = ReturnStmt::Create(Context, ReturnLoc, /* RetExpr=*/nullptr,
                              /* NRVOCandidate=*/nullptr);
} else {
  assert(RetValExp || HasDependentReturnType)(static_cast<void> (0));
  QualType RetType = RelatedRetType.isNull() ? FnRetType : RelatedRetType;

  // 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.
  if (!HasDependentReturnType && !RetValExp->isTypeDependent()) {
    // we have a non-void function with an expression, continue checking
    InitializedEntity Entity = InitializedEntity::InitializeResult(
        ReturnLoc, RetType, NRVOCandidate != nullptr);
    ExprResult Res = PerformMoveOrCopyInitialization(
        Entity, NRInfo, RetValExp, SupressSimplerImplicitMoves);
    if (Res.isInvalid()) {
      // FIXME: Clean up temporaries here anyway?
      return StmtError();
    }
    RetValExp = Res.getAs<Expr>();

    // If we have a related result type, we need to implicitly
    // convert back to the formal result type.  We can't pretend to
    // initialize the result again --- we might end double-retaining
    // --- so instead we initialize a notional temporary.
    if (!RelatedRetType.isNull()) {
      Entity = InitializedEntity::InitializeRelatedResult(getCurMethodDecl(),
                                                          FnRetType);
      Res = PerformCopyInitialization(Entity, ReturnLoc, RetValExp);
      if (Res.isInvalid()) {
        // FIXME: Clean up temporaries here anyway?
        return StmtError();
      }
      RetValExp = Res.getAs<Expr>();
    }

    CheckReturnValExpr(RetValExp, FnRetType, ReturnLoc, isObjCMethod, Attrs,
                       getCurFunctionDecl());
  }

  if (RetValExp) {
    ExprResult ER =
        ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
    if (ER.isInvalid())
      return StmtError();
    RetValExp = ER.get();
  }
  Result = ReturnStmt::Create(Context, 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 (Result->getNRVOCandidate())
  FunctionScopes.back()->Returns.push_back(Result);

if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
  FunctionScopes.back()->FirstReturnLoc = ReturnLoc;

return Result;
4135}

4137StmtResult
4138Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
                         SourceLocation RParen, Decl *Parm,
                         Stmt *Body) {
VarDecl *Var = cast_or_null<VarDecl>(Parm);
if (Var && Var->isInvalidDecl())
  return StmtError();

return new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body);
4146}

4148StmtResult
4149Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) {
return new (Context) ObjCAtFinallyStmt(AtLoc, Body);
4151}

4153StmtResult
4154Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
                       MultiStmtArg CatchStmts, Stmt *Finally) {
if (!getLangOpts().ObjCExceptions)
  Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try";

setFunctionHasBranchProtectedScope();
unsigned NumCatchStmts = CatchStmts.size();
return ObjCAtTryStmt::Create(Context, AtLoc, Try, CatchStmts.data(),
                             NumCatchStmts, Finally);
4163}

4165StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) {
if (Throw) {
  ExprResult Result = DefaultLvalueConversion(Throw);
  if (Result.isInvalid())
    return StmtError();

  Result = ActOnFinishFullExpr(Result.get(), /*DiscardedValue*/ false);
  if (Result.isInvalid())
    return StmtError();
  Throw = Result.get();

  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::err_objc_throw_expects_object)
                       << Throw->getType() << Throw->getSourceRange());
  }
}

return new (Context) ObjCAtThrowStmt(AtLoc, Throw);
4188}

4190StmtResult
4191Sema::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 must 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::err_rethrow_used_outside_catch));
}
return BuildObjCAtThrowStmt(AtLoc, Throw);
4206}

4208ExprResult
4209Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) {
ExprResult result = DefaultLvalueConversion(operand);
if (result.isInvalid())
  return ExprError();
operand = result.get();

// 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()) {
    if (getLangOpts().CPlusPlus) {
      if (RequireCompleteType(atLoc, type,
                              diag::err_incomplete_receiver_type))
        return Diag(atLoc, diag::err_objc_synchronized_expects_object)
                 << type << operand->getSourceRange();

      ExprResult result = PerformContextuallyConvertToObjCPointer(operand);
      if (result.isInvalid())
        return ExprError();
      if (!result.isUsable())
        return Diag(atLoc, diag::err_objc_synchronized_expects_object)
                 << type << operand->getSourceRange();

      operand = result.get();
    } else {
        return Diag(atLoc, diag::err_objc_synchronized_expects_object)
                 << type << operand->getSourceRange();
    }
  }
}

// The operand to @synchronized is a full-expression.
return ActOnFinishFullExpr(operand, /*DiscardedValue*/ false);
4244}

4246StmtResult
4247Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr,
                                Stmt *SyncBody) {
// We can't jump into or indirect-jump out of a @synchronized block.
setFunctionHasBranchProtectedScope();
return new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody);
4252}

4254/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
4255/// and creates a proper catch handler from them.
4256StmtResult
4257Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
                       Stmt *HandlerBlock) {
// There's nothing to test that ActOnExceptionDecl didn't already test.
return new (Context)
    CXXCatchStmt(CatchLoc, cast_or_null<VarDecl>(ExDecl), HandlerBlock);
4262}

4264StmtResult
4265Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) {
setFunctionHasBranchProtectedScope();
return new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body);
4268}

4270namespace {
4271class CatchHandlerType {
QualType QT;
unsigned IsPointer : 1;

// This is a special constructor to be used only with DenseMapInfo's
// getEmptyKey() and getTombstoneKey() functions.
friend struct llvm::DenseMapInfo<CatchHandlerType>;
enum Unique { ForDenseMap };
CatchHandlerType(QualType QT, Unique) : QT(QT), IsPointer(false) {}

4281public:
/// Used when creating a CatchHandlerType from a handler type; will determine
/// whether the type is a pointer or reference and will strip off the top
/// level pointer and cv-qualifiers.
CatchHandlerType(QualType Q) : QT(Q), IsPointer(false) {
  if (QT->isPointerType())
    IsPointer = true;

  if (IsPointer || QT->isReferenceType())
    QT = QT->getPointeeType();
  QT = QT.getUnqualifiedType();
}

/// Used when creating a CatchHandlerType from a base class type; pretends the
/// type passed in had the pointer qualifier, does not need to get an
/// unqualified type.
CatchHandlerType(QualType QT, bool IsPointer)
    : QT(QT), IsPointer(IsPointer) {}

QualType underlying() const { return QT; }
bool isPointer() const { return IsPointer; }

friend bool operator==(const CatchHandlerType &LHS,
                       const CatchHandlerType &RHS) {
  // If the pointer qualification does not match, we can return early.
  if (LHS.IsPointer != RHS.IsPointer)
    return false;
  // Otherwise, check the underlying type without cv-qualifiers.
  return LHS.QT == RHS.QT;
}
4311};
4312} // namespace

4314namespace llvm {
4315template <> struct DenseMapInfo<CatchHandlerType> {
static CatchHandlerType getEmptyKey() {
  return CatchHandlerType(DenseMapInfo<QualType>::getEmptyKey(),
                     CatchHandlerType::ForDenseMap);
}

static CatchHandlerType getTombstoneKey() {
  return CatchHandlerType(DenseMapInfo<QualType>::getTombstoneKey(),
                     CatchHandlerType::ForDenseMap);
}

static unsigned getHashValue(const CatchHandlerType &Base) {
  return DenseMapInfo<QualType>::getHashValue(Base.underlying());
}

static bool isEqual(const CatchHandlerType &LHS,
                    const CatchHandlerType &RHS) {
  return LHS == RHS;
}
4334};
4335}

4337namespace {
4338class CatchTypePublicBases {
ASTContext &Ctx;
const llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> &TypesToCheck;
const bool CheckAgainstPointer;

CXXCatchStmt *FoundHandler;
CanQualType FoundHandlerType;

4346public:
CatchTypePublicBases(
    ASTContext &Ctx,
    const llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> &T, bool C)
    : Ctx(Ctx), TypesToCheck(T), CheckAgainstPointer(C),
      FoundHandler(nullptr) {}

CXXCatchStmt *getFoundHandler() const { return FoundHandler; }
CanQualType getFoundHandlerType() const { return FoundHandlerType; }

bool operator()(const CXXBaseSpecifier *S, CXXBasePath &) {
  if (S->getAccessSpecifier() == AccessSpecifier::AS_public) {
    CatchHandlerType Check(S->getType(), CheckAgainstPointer);
    const auto &M = TypesToCheck;
    auto I = M.find(Check);
    if (I != M.end()) {
      FoundHandler = I->second;
      FoundHandlerType = Ctx.getCanonicalType(S->getType());
      return true;
    }
  }
  return false;
}
4369};
4370}

4372/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
4373/// handlers and creates a try statement from them.
4374StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
                                ArrayRef<Stmt *> Handlers) {
// Don't report an error if 'try' is used in system headers.
if (!getLangOpts().CXXExceptions &&
    !getSourceManager().isInSystemHeader(TryLoc) && !getLangOpts().CUDA) {
  // Delay error emission for the OpenMP device code.
  targetDiag(TryLoc, diag::err_exceptions_disabled) << "try";
}

// Exceptions aren't allowed in CUDA device code.
if (getLangOpts().CUDA)
  CUDADiagIfDeviceCode(TryLoc, diag::err_cuda_device_exceptions)
      << "try" << CurrentCUDATarget();

if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
  Diag(TryLoc, diag::err_omp_simd_region_cannot_use_stmt) << "try";

sema::FunctionScopeInfo *FSI = getCurFunction();

// C++ try is incompatible with SEH __try.
if (!getLangOpts().Borland && FSI->FirstSEHTryLoc.isValid()) {
  Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
  Diag(FSI->FirstSEHTryLoc, diag::note_conflicting_try_here) << "'__try'";
}

const unsigned NumHandlers = Handlers.size();
assert(!Handlers.empty() &&(static_cast<void> (0))
       "The parser shouldn't call this if there are no handlers.")(static_cast<void> (0));

llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> HandledTypes;
for (unsigned i = 0; i < NumHandlers; ++i) {
  CXXCatchStmt *H = cast<CXXCatchStmt>(Handlers[i]);

  // Diagnose when the handler is a catch-all handler, but it isn't the last
  // handler for the try block. [except.handle]p5. Also, skip exception
  // declarations that are invalid, since we can't usefully report on them.
  if (!H->getExceptionDecl()) {
    if (i < NumHandlers - 1)
      return StmtError(Diag(H->getBeginLoc(), diag::err_early_catch_all));
    continue;
  } else if (H->getExceptionDecl()->isInvalidDecl())
    continue;

  // Walk the type hierarchy to diagnose when this type has already been
  // handled (duplication), or cannot be handled (derivation inversion). We
  // ignore top-level cv-qualifiers, per [except.handle]p3
  CatchHandlerType HandlerCHT =
      (QualType)Context.getCanonicalType(H->getCaughtType());

  // We can ignore whether the type is a reference or a pointer; we need the
  // underlying declaration type in order to get at the underlying record
  // decl, if there is one.
  QualType Underlying = HandlerCHT.underlying();
  if (auto *RD = Underlying->getAsCXXRecordDecl()) {
    if (!RD->hasDefinition())
      continue;
    // Check that none of the public, unambiguous base classes are in the
    // map ([except.handle]p1). Give the base classes the same pointer
    // qualification as the original type we are basing off of. This allows
    // comparison against the handler type using the same top-level pointer
    // as the original type.
    CXXBasePaths Paths;
    Paths.setOrigin(RD);
    CatchTypePublicBases CTPB(Context, HandledTypes, HandlerCHT.isPointer());
    if (RD->lookupInBases(CTPB, Paths)) {
      const CXXCatchStmt *Problem = CTPB.getFoundHandler();
      if (!Paths.isAmbiguous(CTPB.getFoundHandlerType())) {
        Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
             diag::warn_exception_caught_by_earlier_handler)
            << H->getCaughtType();
        Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
              diag::note_previous_exception_handler)
            << Problem->getCaughtType();
      }
    }
  }

  // Add the type the list of ones we have handled; diagnose if we've already
  // handled it.
  auto R = HandledTypes.insert(std::make_pair(H->getCaughtType(), H));
  if (!R.second) {
    const CXXCatchStmt *Problem = R.first->second;
    Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
         diag::warn_exception_caught_by_earlier_handler)
        << H->getCaughtType();
    Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
         diag::note_previous_exception_handler)
        << Problem->getCaughtType();
  }
}

FSI->setHasCXXTry(TryLoc);

return CXXTryStmt::Create(Context, TryLoc, TryBlock, Handlers);
4468}

4470StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc,
                                Stmt *TryBlock, Stmt *Handler) {
assert(TryBlock && Handler)(static_cast<void> (0));

sema::FunctionScopeInfo *FSI = getCurFunction();

// SEH __try is incompatible with C++ try. Borland appears to support this,
// however.
if (!getLangOpts().Borland) {
  if (FSI->FirstCXXTryLoc.isValid()) {
    Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
    Diag(FSI->FirstCXXTryLoc, diag::note_conflicting_try_here) << "'try'";
  }
}

FSI->setHasSEHTry(TryLoc);

// Reject __try in Obj-C methods, blocks, and captured decls, since we don't
// track if they use SEH.
DeclContext *DC = CurContext;
while (DC && !DC->isFunctionOrMethod())
  DC = DC->getParent();
FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(DC);
if (FD)
  FD->setUsesSEHTry(true);
else
  Diag(TryLoc, diag::err_seh_try_outside_functions);

// Reject __try on unsupported targets.
if (!Context.getTargetInfo().isSEHTrySupported())
  Diag(TryLoc, diag::err_seh_try_unsupported);

return SEHTryStmt::Create(Context, IsCXXTry, TryLoc, TryBlock, Handler);
4503}

4505StmtResult Sema::ActOnSEHExceptBlock(SourceLocation Loc, Expr *FilterExpr,
                                   Stmt *Block) {
assert(FilterExpr && Block)(static_cast<void> (0));
QualType FTy = FilterExpr->getType();
if (!FTy->isIntegerType() && !FTy->isDependentType()) {
  return StmtError(
      Diag(FilterExpr->getExprLoc(), diag::err_filter_expression_integral)
      << FTy);
}
return SEHExceptStmt::Create(Context, Loc, FilterExpr, Block);
4515}

4517void Sema::ActOnStartSEHFinallyBlock() {
CurrentSEHFinally.push_back(CurScope);
4519}

4521void Sema::ActOnAbortSEHFinallyBlock() {
CurrentSEHFinally.pop_back();
4523}

4525StmtResult Sema::ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block) {
assert(Block)(static_cast<void> (0));
CurrentSEHFinally.pop_back();
return SEHFinallyStmt::Create(Context, Loc, Block);
4529}

4531StmtResult
4532Sema::ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope) {
Scope *SEHTryParent = CurScope;
while (SEHTryParent && !SEHTryParent->isSEHTryScope())
  SEHTryParent = SEHTryParent->getParent();
if (!SEHTryParent)
  return StmtError(Diag(Loc, diag::err_ms___leave_not_in___try));
CheckJumpOutOfSEHFinally(*this, Loc, *SEHTryParent);

return new (Context) SEHLeaveStmt(Loc);
4541}

4543StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
                                          bool IsIfExists,
                                          NestedNameSpecifierLoc QualifierLoc,
                                          DeclarationNameInfo NameInfo,
                                          Stmt *Nested)
4548{
return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists,
                                           QualifierLoc, NameInfo,
                                           cast<CompoundStmt>(Nested));
4552}


4555StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
                                          bool IsIfExists,
                                          CXXScopeSpec &SS,
                                          UnqualifiedId &Name,
                                          Stmt *Nested) {
return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists,
                                  SS.getWithLocInContext(Context),
                                  GetNameFromUnqualifiedId(Name),
                                  Nested);
4564}

4566RecordDecl*
4567Sema::CreateCapturedStmtRecordDecl(CapturedDecl *&CD, SourceLocation Loc,
                                 unsigned NumParams) {
DeclContext *DC = CurContext;
while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
  DC = DC->getParent();

RecordDecl *RD = nullptr;
if (getLangOpts().CPlusPlus)
  RD = CXXRecordDecl::Create(Context, TTK_Struct, DC, Loc, Loc,
                             /*Id=*/nullptr);
else
  RD = RecordDecl::Create(Context, TTK_Struct, DC, Loc, Loc, /*Id=*/nullptr);

RD->setCapturedRecord();
DC->addDecl(RD);
RD->setImplicit();
RD->startDefinition();

assert(NumParams > 0 && "CapturedStmt requires context parameter")(static_cast<void> (0));
CD = CapturedDecl::Create(Context, CurContext, NumParams);
DC->addDecl(CD);
return RD;
4589}

4591static bool
4592buildCapturedStmtCaptureList(Sema &S, CapturedRegionScopeInfo *RSI,
                           SmallVectorImpl<CapturedStmt::Capture> &Captures,
                           SmallVectorImpl<Expr *> &CaptureInits) {
for (const sema::Capture &Cap : RSI->Captures) {
  if (Cap.isInvalid())
    continue;

  // Form the initializer for the capture.
  ExprResult Init = S.BuildCaptureInit(Cap, Cap.getLocation(),
                                       RSI->CapRegionKind == CR_OpenMP);

  // FIXME: Bail out now if the capture is not used and the initializer has
  // no side-effects.

  // Create a field for this capture.
  FieldDecl *Field = S.BuildCaptureField(RSI->TheRecordDecl, Cap);

  // Add the capture to our list of captures.
  if (Cap.isThisCapture()) {
    Captures.push_back(CapturedStmt::Capture(Cap.getLocation(),
                                             CapturedStmt::VCK_This));
  } else if (Cap.isVLATypeCapture()) {
    Captures.push_back(
        CapturedStmt::Capture(Cap.getLocation(), CapturedStmt::VCK_VLAType));
  } else {
    assert(Cap.isVariableCapture() && "unknown kind of capture")(static_cast<void> (0));

    if (S.getLangOpts().OpenMP && RSI->CapRegionKind == CR_OpenMP)
      S.setOpenMPCaptureKind(Field, Cap.getVariable(), RSI->OpenMPLevel);

    Captures.push_back(CapturedStmt::Capture(Cap.getLocation(),
                                             Cap.isReferenceCapture()
                                                 ? CapturedStmt::VCK_ByRef
                                                 : CapturedStmt::VCK_ByCopy,
                                             Cap.getVariable()));
  }
  CaptureInits.push_back(Init.get());
}
return false;
4631}

4633void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
                                  CapturedRegionKind Kind,
                                  unsigned NumParams) {
CapturedDecl *CD = nullptr;
RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams);

// Build the context parameter
DeclContext *DC = CapturedDecl::castToDeclContext(CD);
IdentifierInfo *ParamName = &Context.Idents.get("__context");
QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
auto *Param =
    ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
                              ImplicitParamDecl::CapturedContext);
DC->addDecl(Param);

CD->setContextParam(0, Param);

// Enter the capturing scope for this captured region.
PushCapturedRegionScope(CurScope, CD, RD, Kind);

if (CurScope)
  PushDeclContext(CurScope, CD);
else
  CurContext = CD;

PushExpressionEvaluationContext(
    ExpressionEvaluationContext::PotentiallyEvaluated);
4660}

4662void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
                                  CapturedRegionKind Kind,
                                  ArrayRef<CapturedParamNameType> Params,
                                  unsigned OpenMPCaptureLevel) {
CapturedDecl *CD = nullptr;
RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, Params.size());

// Build the context parameter
DeclContext *DC = CapturedDecl::castToDeclContext(CD);
bool ContextIsFound = false;
unsigned ParamNum = 0;
for (ArrayRef<CapturedParamNameType>::iterator I = Params.begin(),
                                               E = Params.end();
     I != E; ++I, ++ParamNum) {
  if (I->second.isNull()) {
    assert(!ContextIsFound &&(static_cast<void> (0))
           "null type has been found already for '__context' parameter")(static_cast<void> (0));
    IdentifierInfo *ParamName = &Context.Idents.get("__context");
    QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD))
                             .withConst()
                             .withRestrict();
    auto *Param =
        ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
                                  ImplicitParamDecl::CapturedContext);
    DC->addDecl(Param);
    CD->setContextParam(ParamNum, Param);
    ContextIsFound = true;
  } else {
    IdentifierInfo *ParamName = &Context.Idents.get(I->first);
    auto *Param =
        ImplicitParamDecl::Create(Context, DC, Loc, ParamName, I->second,
                                  ImplicitParamDecl::CapturedContext);
    DC->addDecl(Param);
    CD->setParam(ParamNum, Param);
  }
}
assert(ContextIsFound && "no null type for '__context' parameter")(static_cast<void> (0));
if (!ContextIsFound) {
  // Add __context implicitly if it is not specified.
  IdentifierInfo *ParamName = &Context.Idents.get("__context");
  QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
  auto *Param =
      ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
                                ImplicitParamDecl::CapturedContext);
  DC->addDecl(Param);
  CD->setContextParam(ParamNum, Param);
}
// Enter the capturing scope for this captured region.
PushCapturedRegionScope(CurScope, CD, RD, Kind, OpenMPCaptureLevel);

if (CurScope)
  PushDeclContext(CurScope, CD);
else
  CurContext = CD;

PushExpressionEvaluationContext(
    ExpressionEvaluationContext::PotentiallyEvaluated);
4719}

4721void Sema::ActOnCapturedRegionError() {
DiscardCleanupsInEvaluationContext();
PopExpressionEvaluationContext();
PopDeclContext();
PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(ScopeRAII.get());

RecordDecl *Record = RSI->TheRecordDecl;
Record->setInvalidDecl();

SmallVector<Decl*, 4> Fields(Record->fields());
ActOnFields(/*Scope=*/nullptr, Record->getLocation(), Record, Fields,
            SourceLocation(), SourceLocation(), ParsedAttributesView());
4734}

4736StmtResult Sema::ActOnCapturedRegionEnd(Stmt *S) {
// Leave the captured scope before we start creating captures in the
// enclosing scope.
DiscardCleanupsInEvaluationContext();
PopExpressionEvaluationContext();
PopDeclContext();
PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(ScopeRAII.get());

SmallVector<CapturedStmt::Capture, 4> Captures;
SmallVector<Expr *, 4> CaptureInits;
if (buildCapturedStmtCaptureList(*this, RSI, Captures, CaptureInits))
  return StmtError();

CapturedDecl *CD = RSI->TheCapturedDecl;
RecordDecl *RD = RSI->TheRecordDecl;

CapturedStmt *Res = CapturedStmt::Create(
    getASTContext(), S, static_cast<CapturedRegionKind>(RSI->CapRegionKind),
    Captures, CaptureInits, CD, RD);

CD->setBody(Res->getCapturedStmt());
RD->completeDefinition();

return Res;
4761}