YQ Connector: support managed ClickHouse

Со стороны dqrun можно обратиться к инстансу коннектора, который работает на streaming стенде, и извлечь данные из облачного CH.

1 files changed, 737 insertions, 0 deletions

diff --git a/contrib/libs/clang16/lib/AST/ExprClassification.cpp b/contrib/libs/clang16/lib/AST/ExprClassification.cpp
new file mode 100644
index 0000000000..12193b7812
--- /dev/null
+++ b/contrib/libs/clang16/lib/AST/ExprClassification.cpp
@@ -0,0 +1,737 @@
+//===- ExprClassification.cpp - Expression AST Node Implementation --------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements Expr::classify.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/Expr.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/ExprObjC.h"
+#include "llvm/Support/ErrorHandling.h"
+
+using namespace clang;
+
+using Cl = Expr::Classification;
+
+static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E);
+static Cl::Kinds ClassifyDecl(ASTContext &Ctx, const Decl *D);
+static Cl::Kinds ClassifyUnnamed(ASTContext &Ctx, QualType T);
+static Cl::Kinds ClassifyMemberExpr(ASTContext &Ctx, const MemberExpr *E);
+static Cl::Kinds ClassifyBinaryOp(ASTContext &Ctx, const BinaryOperator *E);
+static Cl::Kinds ClassifyConditional(ASTContext &Ctx,
+                                     const Expr *trueExpr,
+                                     const Expr *falseExpr);
+static Cl::ModifiableType IsModifiable(ASTContext &Ctx, const Expr *E,
+                                       Cl::Kinds Kind, SourceLocation &Loc);
+
+Cl Expr::ClassifyImpl(ASTContext &Ctx, SourceLocation *Loc) const {
+  assert(!TR->isReferenceType() && "Expressions can't have reference type.");
+
+  Cl::Kinds kind = ClassifyInternal(Ctx, this);
+  // C99 6.3.2.1: An lvalue is an expression with an object type or an
+  //   incomplete type other than void.
+  if (!Ctx.getLangOpts().CPlusPlus) {
+    // Thus, no functions.
+    if (TR->isFunctionType() || TR == Ctx.OverloadTy)
+      kind = Cl::CL_Function;
+    // No void either, but qualified void is OK because it is "other than void".
+    // Void "lvalues" are classified as addressable void values, which are void
+    // expressions whose address can be taken.
+    else if (TR->isVoidType() && !TR.hasQualifiers())
+      kind = (kind == Cl::CL_LValue ? Cl::CL_AddressableVoid : Cl::CL_Void);
+  }
+
+  // Enable this assertion for testing.
+  switch (kind) {
+  case Cl::CL_LValue:
+    assert(isLValue());
+    break;
+  case Cl::CL_XValue:
+    assert(isXValue());
+    break;
+  case Cl::CL_Function:
+  case Cl::CL_Void:
+  case Cl::CL_AddressableVoid:
+  case Cl::CL_DuplicateVectorComponents:
+  case Cl::CL_MemberFunction:
+  case Cl::CL_SubObjCPropertySetting:
+  case Cl::CL_ClassTemporary:
+  case Cl::CL_ArrayTemporary:
+  case Cl::CL_ObjCMessageRValue:
+  case Cl::CL_PRValue:
+    assert(isPRValue());
+    break;
+  }
+
+  Cl::ModifiableType modifiable = Cl::CM_Untested;
+  if (Loc)
+    modifiable = IsModifiable(Ctx, this, kind, *Loc);
+  return Classification(kind, modifiable);
+}
+
+/// Classify an expression which creates a temporary, based on its type.
+static Cl::Kinds ClassifyTemporary(QualType T) {
+  if (T->isRecordType())
+    return Cl::CL_ClassTemporary;
+  if (T->isArrayType())
+    return Cl::CL_ArrayTemporary;
+
+  // No special classification: these don't behave differently from normal
+  // prvalues.
+  return Cl::CL_PRValue;
+}
+
+static Cl::Kinds ClassifyExprValueKind(const LangOptions &Lang,
+                                       const Expr *E,
+                                       ExprValueKind Kind) {
+  switch (Kind) {
+  case VK_PRValue:
+    return Lang.CPlusPlus ? ClassifyTemporary(E->getType()) : Cl::CL_PRValue;
+  case VK_LValue:
+    return Cl::CL_LValue;
+  case VK_XValue:
+    return Cl::CL_XValue;
+  }
+  llvm_unreachable("Invalid value category of implicit cast.");
+}
+
+static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E) {
+  // This function takes the first stab at classifying expressions.
+  const LangOptions &Lang = Ctx.getLangOpts();
+
+  switch (E->getStmtClass()) {
+  case Stmt::NoStmtClass:
+#define ABSTRACT_STMT(Kind)
+#define STMT(Kind, Base) case Expr::Kind##Class:
+#define EXPR(Kind, Base)
+#include "clang/AST/StmtNodes.inc"
+    llvm_unreachable("cannot classify a statement");
+
+    // First come the expressions that are always lvalues, unconditionally.
+  case Expr::ObjCIsaExprClass:
+    // C++ [expr.prim.general]p1: A string literal is an lvalue.
+  case Expr::StringLiteralClass:
+    // @encode is equivalent to its string
+  case Expr::ObjCEncodeExprClass:
+    // __func__ and friends are too.
+  case Expr::PredefinedExprClass:
+    // Property references are lvalues
+  case Expr::ObjCSubscriptRefExprClass:
+  case Expr::ObjCPropertyRefExprClass:
+    // C++ [expr.typeid]p1: The result of a typeid expression is an lvalue of...
+  case Expr::CXXTypeidExprClass:
+  case Expr::CXXUuidofExprClass:
+    // Unresolved lookups and uncorrected typos get classified as lvalues.
+    // FIXME: Is this wise? Should they get their own kind?
+  case Expr::UnresolvedLookupExprClass:
+  case Expr::UnresolvedMemberExprClass:
+  case Expr::TypoExprClass:
+  case Expr::DependentCoawaitExprClass:
+  case Expr::CXXDependentScopeMemberExprClass:
+  case Expr::DependentScopeDeclRefExprClass:
+    // ObjC instance variables are lvalues
+    // FIXME: ObjC++0x might have different rules
+  case Expr::ObjCIvarRefExprClass:
+  case Expr::FunctionParmPackExprClass:
+  case Expr::MSPropertyRefExprClass:
+  case Expr::MSPropertySubscriptExprClass:
+  case Expr::OMPArraySectionExprClass:
+  case Expr::OMPArrayShapingExprClass:
+  case Expr::OMPIteratorExprClass:
+    return Cl::CL_LValue;
+
+    // C99 6.5.2.5p5 says that compound literals are lvalues.
+    // In C++, they're prvalue temporaries, except for file-scope arrays.
+  case Expr::CompoundLiteralExprClass:
+    return !E->isLValue() ? ClassifyTemporary(E->getType()) : Cl::CL_LValue;
+
+    // Expressions that are prvalues.
+  case Expr::CXXBoolLiteralExprClass:
+  case Expr::CXXPseudoDestructorExprClass:
+  case Expr::UnaryExprOrTypeTraitExprClass:
+  case Expr::CXXNewExprClass:
+  case Expr::CXXNullPtrLiteralExprClass:
+  case Expr::ImaginaryLiteralClass:
+  case Expr::GNUNullExprClass:
+  case Expr::OffsetOfExprClass:
+  case Expr::CXXThrowExprClass:
+  case Expr::ShuffleVectorExprClass:
+  case Expr::ConvertVectorExprClass:
+  case Expr::IntegerLiteralClass:
+  case Expr::FixedPointLiteralClass:
+  case Expr::CharacterLiteralClass:
+  case Expr::AddrLabelExprClass:
+  case Expr::CXXDeleteExprClass:
+  case Expr::ImplicitValueInitExprClass:
+  case Expr::BlockExprClass:
+  case Expr::FloatingLiteralClass:
+  case Expr::CXXNoexceptExprClass:
+  case Expr::CXXScalarValueInitExprClass:
+  case Expr::TypeTraitExprClass:
+  case Expr::ArrayTypeTraitExprClass:
+  case Expr::ExpressionTraitExprClass:
+  case Expr::ObjCSelectorExprClass:
+  case Expr::ObjCProtocolExprClass:
+  case Expr::ObjCStringLiteralClass:
+  case Expr::ObjCBoxedExprClass:
+  case Expr::ObjCArrayLiteralClass:
+  case Expr::ObjCDictionaryLiteralClass:
+  case Expr::ObjCBoolLiteralExprClass:
+  case Expr::ObjCAvailabilityCheckExprClass:
+  case Expr::ParenListExprClass:
+  case Expr::SizeOfPackExprClass:
+  case Expr::SubstNonTypeTemplateParmPackExprClass:
+  case Expr::AsTypeExprClass:
+  case Expr::ObjCIndirectCopyRestoreExprClass:
+  case Expr::AtomicExprClass:
+  case Expr::CXXFoldExprClass:
+  case Expr::ArrayInitLoopExprClass:
+  case Expr::ArrayInitIndexExprClass:
+  case Expr::NoInitExprClass:
+  case Expr::DesignatedInitUpdateExprClass:
+  case Expr::SourceLocExprClass:
+  case Expr::ConceptSpecializationExprClass:
+  case Expr::RequiresExprClass:
+    return Cl::CL_PRValue;
+
+  // Make HLSL this reference-like
+  case Expr::CXXThisExprClass:
+    return Lang.HLSL ? Cl::CL_LValue : Cl::CL_PRValue;
+
+  case Expr::ConstantExprClass:
+    return ClassifyInternal(Ctx, cast<ConstantExpr>(E)->getSubExpr());
+
+    // Next come the complicated cases.
+  case Expr::SubstNonTypeTemplateParmExprClass:
+    return ClassifyInternal(Ctx,
+                 cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement());
+
+    // C, C++98 [expr.sub]p1: The result is an lvalue of type "T".
+    // C++11 (DR1213): in the case of an array operand, the result is an lvalue
+    //                 if that operand is an lvalue and an xvalue otherwise.
+    // Subscripting vector types is more like member access.
+  case Expr::ArraySubscriptExprClass:
+    if (cast<ArraySubscriptExpr>(E)->getBase()->getType()->isVectorType())
+      return ClassifyInternal(Ctx, cast<ArraySubscriptExpr>(E)->getBase());
+    if (Lang.CPlusPlus11) {
+      // Step over the array-to-pointer decay if present, but not over the
+      // temporary materialization.
+      auto *Base = cast<ArraySubscriptExpr>(E)->getBase()->IgnoreImpCasts();
+      if (Base->getType()->isArrayType())
+        return ClassifyInternal(Ctx, Base);
+    }
+    return Cl::CL_LValue;
+
+  // Subscripting matrix types behaves like member accesses.
+  case Expr::MatrixSubscriptExprClass:
+    return ClassifyInternal(Ctx, cast<MatrixSubscriptExpr>(E)->getBase());
+
+    // C++ [expr.prim.general]p3: The result is an lvalue if the entity is a
+    //   function or variable and a prvalue otherwise.
+  case Expr::DeclRefExprClass:
+    if (E->getType() == Ctx.UnknownAnyTy)
+      return isa<FunctionDecl>(cast<DeclRefExpr>(E)->getDecl())
+               ? Cl::CL_PRValue : Cl::CL_LValue;
+    return ClassifyDecl(Ctx, cast<DeclRefExpr>(E)->getDecl());
+
+    // Member access is complex.
+  case Expr::MemberExprClass:
+    return ClassifyMemberExpr(Ctx, cast<MemberExpr>(E));
+
+  case Expr::UnaryOperatorClass:
+    switch (cast<UnaryOperator>(E)->getOpcode()) {
+      // C++ [expr.unary.op]p1: The unary * operator performs indirection:
+      //   [...] the result is an lvalue referring to the object or function
+      //   to which the expression points.
+    case UO_Deref:
+      return Cl::CL_LValue;
+
+      // GNU extensions, simply look through them.
+    case UO_Extension:
+      return ClassifyInternal(Ctx, cast<UnaryOperator>(E)->getSubExpr());
+
+    // Treat _Real and _Imag basically as if they were member
+    // expressions:  l-value only if the operand is a true l-value.
+    case UO_Real:
+    case UO_Imag: {
+      const Expr *Op = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens();
+      Cl::Kinds K = ClassifyInternal(Ctx, Op);
+      if (K != Cl::CL_LValue) return K;
+
+      if (isa<ObjCPropertyRefExpr>(Op))
+        return Cl::CL_SubObjCPropertySetting;
+      return Cl::CL_LValue;
+    }
+
+      // C++ [expr.pre.incr]p1: The result is the updated operand; it is an
+      //   lvalue, [...]
+      // Not so in C.
+    case UO_PreInc:
+    case UO_PreDec:
+      return Lang.CPlusPlus ? Cl::CL_LValue : Cl::CL_PRValue;
+
+    default:
+      return Cl::CL_PRValue;
+    }
+
+  case Expr::RecoveryExprClass:
+  case Expr::OpaqueValueExprClass:
+    return ClassifyExprValueKind(Lang, E, E->getValueKind());
+
+    // Pseudo-object expressions can produce l-values with reference magic.
+  case Expr::PseudoObjectExprClass:
+    return ClassifyExprValueKind(Lang, E,
+                                 cast<PseudoObjectExpr>(E)->getValueKind());
+
+    // Implicit casts are lvalues if they're lvalue casts. Other than that, we
+    // only specifically record class temporaries.
+  case Expr::ImplicitCastExprClass:
+    return ClassifyExprValueKind(Lang, E, E->getValueKind());
+
+    // C++ [expr.prim.general]p4: The presence of parentheses does not affect
+    //   whether the expression is an lvalue.
+  case Expr::ParenExprClass:
+    return ClassifyInternal(Ctx, cast<ParenExpr>(E)->getSubExpr());
+
+    // C11 6.5.1.1p4: [A generic selection] is an lvalue, a function designator,
+    // or a void expression if its result expression is, respectively, an
+    // lvalue, a function designator, or a void expression.
+  case Expr::GenericSelectionExprClass:
+    if (cast<GenericSelectionExpr>(E)->isResultDependent())
+      return Cl::CL_PRValue;
+    return ClassifyInternal(Ctx,cast<GenericSelectionExpr>(E)->getResultExpr());
+
+  case Expr::BinaryOperatorClass:
+  case Expr::CompoundAssignOperatorClass:
+    // C doesn't have any binary expressions that are lvalues.
+    if (Lang.CPlusPlus)
+      return ClassifyBinaryOp(Ctx, cast<BinaryOperator>(E));
+    return Cl::CL_PRValue;
+
+  case Expr::CallExprClass:
+  case Expr::CXXOperatorCallExprClass:
+  case Expr::CXXMemberCallExprClass:
+  case Expr::UserDefinedLiteralClass:
+  case Expr::CUDAKernelCallExprClass:
+    return ClassifyUnnamed(Ctx, cast<CallExpr>(E)->getCallReturnType(Ctx));
+
+  case Expr::CXXRewrittenBinaryOperatorClass:
+    return ClassifyInternal(
+        Ctx, cast<CXXRewrittenBinaryOperator>(E)->getSemanticForm());
+
+    // __builtin_choose_expr is equivalent to the chosen expression.
+  case Expr::ChooseExprClass:
+    return ClassifyInternal(Ctx, cast<ChooseExpr>(E)->getChosenSubExpr());
+
+    // Extended vector element access is an lvalue unless there are duplicates
+    // in the shuffle expression.
+  case Expr::ExtVectorElementExprClass:
+    if (cast<ExtVectorElementExpr>(E)->containsDuplicateElements())
+      return Cl::CL_DuplicateVectorComponents;
+    if (cast<ExtVectorElementExpr>(E)->isArrow())
+      return Cl::CL_LValue;
+    return ClassifyInternal(Ctx, cast<ExtVectorElementExpr>(E)->getBase());
+
+    // Simply look at the actual default argument.
+  case Expr::CXXDefaultArgExprClass:
+    return ClassifyInternal(Ctx, cast<CXXDefaultArgExpr>(E)->getExpr());
+
+    // Same idea for default initializers.
+  case Expr::CXXDefaultInitExprClass:
+    return ClassifyInternal(Ctx, cast<CXXDefaultInitExpr>(E)->getExpr());
+
+    // Same idea for temporary binding.
+  case Expr::CXXBindTemporaryExprClass:
+    return ClassifyInternal(Ctx, cast<CXXBindTemporaryExpr>(E)->getSubExpr());
+
+    // And the cleanups guard.
+  case Expr::ExprWithCleanupsClass:
+    return ClassifyInternal(Ctx, cast<ExprWithCleanups>(E)->getSubExpr());
+
+    // Casts depend completely on the target type. All casts work the same.
+  case Expr::CStyleCastExprClass:
+  case Expr::CXXFunctionalCastExprClass:
+  case Expr::CXXStaticCastExprClass:
+  case Expr::CXXDynamicCastExprClass:
+  case Expr::CXXReinterpretCastExprClass:
+  case Expr::CXXConstCastExprClass:
+  case Expr::CXXAddrspaceCastExprClass:
+  case Expr::ObjCBridgedCastExprClass:
+  case Expr::BuiltinBitCastExprClass:
+    // Only in C++ can casts be interesting at all.
+    if (!Lang.CPlusPlus) return Cl::CL_PRValue;
+    return ClassifyUnnamed(Ctx, cast<ExplicitCastExpr>(E)->getTypeAsWritten());
+
+  case Expr::CXXUnresolvedConstructExprClass:
+    return ClassifyUnnamed(Ctx,
+                      cast<CXXUnresolvedConstructExpr>(E)->getTypeAsWritten());
+
+  case Expr::BinaryConditionalOperatorClass: {
+    if (!Lang.CPlusPlus) return Cl::CL_PRValue;
+    const auto *co = cast<BinaryConditionalOperator>(E);
+    return ClassifyConditional(Ctx, co->getTrueExpr(), co->getFalseExpr());
+  }
+
+  case Expr::ConditionalOperatorClass: {
+    // Once again, only C++ is interesting.
+    if (!Lang.CPlusPlus) return Cl::CL_PRValue;
+    const auto *co = cast<ConditionalOperator>(E);
+    return ClassifyConditional(Ctx, co->getTrueExpr(), co->getFalseExpr());
+  }
+
+    // ObjC message sends are effectively function calls, if the target function
+    // is known.
+  case Expr::ObjCMessageExprClass:
+    if (const ObjCMethodDecl *Method =
+          cast<ObjCMessageExpr>(E)->getMethodDecl()) {
+      Cl::Kinds kind = ClassifyUnnamed(Ctx, Method->getReturnType());
+      return (kind == Cl::CL_PRValue) ? Cl::CL_ObjCMessageRValue : kind;
+    }
+    return Cl::CL_PRValue;
+
+    // Some C++ expressions are always class temporaries.
+  case Expr::CXXConstructExprClass:
+  case Expr::CXXInheritedCtorInitExprClass:
+  case Expr::CXXTemporaryObjectExprClass:
+  case Expr::LambdaExprClass:
+  case Expr::CXXStdInitializerListExprClass:
+    return Cl::CL_ClassTemporary;
+
+  case Expr::VAArgExprClass:
+    return ClassifyUnnamed(Ctx, E->getType());
+
+  case Expr::DesignatedInitExprClass:
+    return ClassifyInternal(Ctx, cast<DesignatedInitExpr>(E)->getInit());
+
+  case Expr::StmtExprClass: {
+    const CompoundStmt *S = cast<StmtExpr>(E)->getSubStmt();
+    if (const auto *LastExpr = dyn_cast_or_null<Expr>(S->body_back()))
+      return ClassifyUnnamed(Ctx, LastExpr->getType());
+    return Cl::CL_PRValue;
+  }
+
+  case Expr::PackExpansionExprClass:
+    return ClassifyInternal(Ctx, cast<PackExpansionExpr>(E)->getPattern());
+
+  case Expr::MaterializeTemporaryExprClass:
+    return cast<MaterializeTemporaryExpr>(E)->isBoundToLvalueReference()
+              ? Cl::CL_LValue
+              : Cl::CL_XValue;
+
+  case Expr::InitListExprClass:
+    // An init list can be an lvalue if it is bound to a reference and
+    // contains only one element. In that case, we look at that element
+    // for an exact classification. Init list creation takes care of the
+    // value kind for us, so we only need to fine-tune.
+    if (E->isPRValue())
+      return ClassifyExprValueKind(Lang, E, E->getValueKind());
+    assert(cast<InitListExpr>(E)->getNumInits() == 1 &&
+           "Only 1-element init lists can be glvalues.");
+    return ClassifyInternal(Ctx, cast<InitListExpr>(E)->getInit(0));
+
+  case Expr::CoawaitExprClass:
+  case Expr::CoyieldExprClass:
+    return ClassifyInternal(Ctx, cast<CoroutineSuspendExpr>(E)->getResumeExpr());
+  case Expr::SYCLUniqueStableNameExprClass:
+    return Cl::CL_PRValue;
+    break;
+
+  case Expr::CXXParenListInitExprClass:
+    if (isa<ArrayType>(E->getType()))
+      return Cl::CL_ArrayTemporary;
+    return Cl::CL_ClassTemporary;
+  }
+
+  llvm_unreachable("unhandled expression kind in classification");
+}
+
+/// ClassifyDecl - Return the classification of an expression referencing the
+/// given declaration.
+static Cl::Kinds ClassifyDecl(ASTContext &Ctx, const Decl *D) {
+  // C++ [expr.prim.general]p6: The result is an lvalue if the entity is a
+  //   function, variable, or data member and a prvalue otherwise.
+  // In C, functions are not lvalues.
+  // In addition, NonTypeTemplateParmDecl derives from VarDecl but isn't an
+  // lvalue unless it's a reference type (C++ [temp.param]p6), so we need to
+  // special-case this.
+
+  if (isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance())
+    return Cl::CL_MemberFunction;
+
+  bool islvalue;
+  if (const auto *NTTParm = dyn_cast<NonTypeTemplateParmDecl>(D))
+    islvalue = NTTParm->getType()->isReferenceType() ||
+               NTTParm->getType()->isRecordType();
+  else
+    islvalue =
+        isa<VarDecl, FieldDecl, IndirectFieldDecl, BindingDecl, MSGuidDecl,
+            UnnamedGlobalConstantDecl, TemplateParamObjectDecl>(D) ||
+        (Ctx.getLangOpts().CPlusPlus &&
+         (isa<FunctionDecl, MSPropertyDecl, FunctionTemplateDecl>(D)));
+
+  return islvalue ? Cl::CL_LValue : Cl::CL_PRValue;
+}
+
+/// ClassifyUnnamed - Return the classification of an expression yielding an
+/// unnamed value of the given type. This applies in particular to function
+/// calls and casts.
+static Cl::Kinds ClassifyUnnamed(ASTContext &Ctx, QualType T) {
+  // In C, function calls are always rvalues.
+  if (!Ctx.getLangOpts().CPlusPlus) return Cl::CL_PRValue;
+
+  // C++ [expr.call]p10: A function call is an lvalue if the result type is an
+  //   lvalue reference type or an rvalue reference to function type, an xvalue
+  //   if the result type is an rvalue reference to object type, and a prvalue
+  //   otherwise.
+  if (T->isLValueReferenceType())
+    return Cl::CL_LValue;
+  const auto *RV = T->getAs<RValueReferenceType>();
+  if (!RV) // Could still be a class temporary, though.
+    return ClassifyTemporary(T);
+
+  return RV->getPointeeType()->isFunctionType() ? Cl::CL_LValue : Cl::CL_XValue;
+}
+
+static Cl::Kinds ClassifyMemberExpr(ASTContext &Ctx, const MemberExpr *E) {
+  if (E->getType() == Ctx.UnknownAnyTy)
+    return (isa<FunctionDecl>(E->getMemberDecl())
+              ? Cl::CL_PRValue : Cl::CL_LValue);
+
+  // Handle C first, it's easier.
+  if (!Ctx.getLangOpts().CPlusPlus) {
+    // C99 6.5.2.3p3
+    // For dot access, the expression is an lvalue if the first part is. For
+    // arrow access, it always is an lvalue.
+    if (E->isArrow())
+      return Cl::CL_LValue;
+    // ObjC property accesses are not lvalues, but get special treatment.
+    Expr *Base = E->getBase()->IgnoreParens();
+    if (isa<ObjCPropertyRefExpr>(Base))
+      return Cl::CL_SubObjCPropertySetting;
+    return ClassifyInternal(Ctx, Base);
+  }
+
+  NamedDecl *Member = E->getMemberDecl();
+  // C++ [expr.ref]p3: E1->E2 is converted to the equivalent form (*(E1)).E2.
+  // C++ [expr.ref]p4: If E2 is declared to have type "reference to T", then
+  //   E1.E2 is an lvalue.
+  if (const auto *Value = dyn_cast<ValueDecl>(Member))
+    if (Value->getType()->isReferenceType())
+      return Cl::CL_LValue;
+
+  //   Otherwise, one of the following rules applies.
+  //   -- If E2 is a static member [...] then E1.E2 is an lvalue.
+  if (isa<VarDecl>(Member) && Member->getDeclContext()->isRecord())
+    return Cl::CL_LValue;
+
+  //   -- If E2 is a non-static data member [...]. If E1 is an lvalue, then
+  //      E1.E2 is an lvalue; if E1 is an xvalue, then E1.E2 is an xvalue;
+  //      otherwise, it is a prvalue.
+  if (isa<FieldDecl>(Member)) {
+    // *E1 is an lvalue
+    if (E->isArrow())
+      return Cl::CL_LValue;
+    Expr *Base = E->getBase()->IgnoreParenImpCasts();
+    if (isa<ObjCPropertyRefExpr>(Base))
+      return Cl::CL_SubObjCPropertySetting;
+    return ClassifyInternal(Ctx, E->getBase());
+  }
+
+  //   -- If E2 is a [...] member function, [...]
+  //      -- If it refers to a static member function [...], then E1.E2 is an
+  //         lvalue; [...]
+  //      -- Otherwise [...] E1.E2 is a prvalue.
+  if (const auto *Method = dyn_cast<CXXMethodDecl>(Member))
+    return Method->isStatic() ? Cl::CL_LValue : Cl::CL_MemberFunction;
+
+  //   -- If E2 is a member enumerator [...], the expression E1.E2 is a prvalue.
+  // So is everything else we haven't handled yet.
+  return Cl::CL_PRValue;
+}
+
+static Cl::Kinds ClassifyBinaryOp(ASTContext &Ctx, const BinaryOperator *E) {
+  assert(Ctx.getLangOpts().CPlusPlus &&
+         "This is only relevant for C++.");
+  // C++ [expr.ass]p1: All [...] return an lvalue referring to the left operand.
+  // Except we override this for writes to ObjC properties.
+  if (E->isAssignmentOp())
+    return (E->getLHS()->getObjectKind() == OK_ObjCProperty
+              ? Cl::CL_PRValue : Cl::CL_LValue);
+
+  // C++ [expr.comma]p1: the result is of the same value category as its right
+  //   operand, [...].
+  if (E->getOpcode() == BO_Comma)
+    return ClassifyInternal(Ctx, E->getRHS());
+
+  // C++ [expr.mptr.oper]p6: The result of a .* expression whose second operand
+  //   is a pointer to a data member is of the same value category as its first
+  //   operand.
+  if (E->getOpcode() == BO_PtrMemD)
+    return (E->getType()->isFunctionType() ||
+            E->hasPlaceholderType(BuiltinType::BoundMember))
+             ? Cl::CL_MemberFunction
+             : ClassifyInternal(Ctx, E->getLHS());
+
+  // C++ [expr.mptr.oper]p6: The result of an ->* expression is an lvalue if its
+  //   second operand is a pointer to data member and a prvalue otherwise.
+  if (E->getOpcode() == BO_PtrMemI)
+    return (E->getType()->isFunctionType() ||
+            E->hasPlaceholderType(BuiltinType::BoundMember))
+             ? Cl::CL_MemberFunction
+             : Cl::CL_LValue;
+
+  // All other binary operations are prvalues.
+  return Cl::CL_PRValue;
+}
+
+static Cl::Kinds ClassifyConditional(ASTContext &Ctx, const Expr *True,
+                                     const Expr *False) {
+  assert(Ctx.getLangOpts().CPlusPlus &&
+         "This is only relevant for C++.");
+
+  // C++ [expr.cond]p2
+  //   If either the second or the third operand has type (cv) void,
+  //   one of the following shall hold:
+  if (True->getType()->isVoidType() || False->getType()->isVoidType()) {
+    // The second or the third operand (but not both) is a (possibly
+    // parenthesized) throw-expression; the result is of the [...] value
+    // category of the other.
+    bool TrueIsThrow = isa<CXXThrowExpr>(True->IgnoreParenImpCasts());
+    bool FalseIsThrow = isa<CXXThrowExpr>(False->IgnoreParenImpCasts());
+    if (const Expr *NonThrow = TrueIsThrow ? (FalseIsThrow ? nullptr : False)
+                                           : (FalseIsThrow ? True : nullptr))
+      return ClassifyInternal(Ctx, NonThrow);
+
+    //   [Otherwise] the result [...] is a prvalue.
+    return Cl::CL_PRValue;
+  }
+
+  // Note that at this point, we have already performed all conversions
+  // according to [expr.cond]p3.
+  // C++ [expr.cond]p4: If the second and third operands are glvalues of the
+  //   same value category [...], the result is of that [...] value category.
+  // C++ [expr.cond]p5: Otherwise, the result is a prvalue.
+  Cl::Kinds LCl = ClassifyInternal(Ctx, True),
+            RCl = ClassifyInternal(Ctx, False);
+  return LCl == RCl ? LCl : Cl::CL_PRValue;
+}
+
+static Cl::ModifiableType IsModifiable(ASTContext &Ctx, const Expr *E,
+                                       Cl::Kinds Kind, SourceLocation &Loc) {
+  // As a general rule, we only care about lvalues. But there are some rvalues
+  // for which we want to generate special results.
+  if (Kind == Cl::CL_PRValue) {
+    // For the sake of better diagnostics, we want to specifically recognize
+    // use of the GCC cast-as-lvalue extension.
+    if (const auto *CE = dyn_cast<ExplicitCastExpr>(E->IgnoreParens())) {
+      if (CE->getSubExpr()->IgnoreParenImpCasts()->isLValue()) {
+        Loc = CE->getExprLoc();
+        return Cl::CM_LValueCast;
+      }
+    }
+  }
+  if (Kind != Cl::CL_LValue)
+    return Cl::CM_RValue;
+
+  // This is the lvalue case.
+  // Functions are lvalues in C++, but not modifiable. (C++ [basic.lval]p6)
+  if (Ctx.getLangOpts().CPlusPlus && E->getType()->isFunctionType())
+    return Cl::CM_Function;
+
+  // Assignment to a property in ObjC is an implicit setter access. But a
+  // setter might not exist.
+  if (const auto *Expr = dyn_cast<ObjCPropertyRefExpr>(E)) {
+    if (Expr->isImplicitProperty() &&
+        Expr->getImplicitPropertySetter() == nullptr)
+      return Cl::CM_NoSetterProperty;
+  }
+
+  CanQualType CT = Ctx.getCanonicalType(E->getType());
+  // Const stuff is obviously not modifiable.
+  if (CT.isConstQualified())
+    return Cl::CM_ConstQualified;
+  if (Ctx.getLangOpts().OpenCL &&
+      CT.getQualifiers().getAddressSpace() == LangAS::opencl_constant)
+    return Cl::CM_ConstAddrSpace;
+
+  // Arrays are not modifiable, only their elements are.
+  if (CT->isArrayType())
+    return Cl::CM_ArrayType;
+  // Incomplete types are not modifiable.
+  if (CT->isIncompleteType())
+    return Cl::CM_IncompleteType;
+
+  // Records with any const fields (recursively) are not modifiable.
+  if (const RecordType *R = CT->getAs<RecordType>())
+    if (R->hasConstFields())
+      return Cl::CM_ConstQualifiedField;
+
+  return Cl::CM_Modifiable;
+}
+
+Expr::LValueClassification Expr::ClassifyLValue(ASTContext &Ctx) const {
+  Classification VC = Classify(Ctx);
+  switch (VC.getKind()) {
+  case Cl::CL_LValue: return LV_Valid;
+  case Cl::CL_XValue: return LV_InvalidExpression;
+  case Cl::CL_Function: return LV_NotObjectType;
+  case Cl::CL_Void: return LV_InvalidExpression;
+  case Cl::CL_AddressableVoid: return LV_IncompleteVoidType;
+  case Cl::CL_DuplicateVectorComponents: return LV_DuplicateVectorComponents;
+  case Cl::CL_MemberFunction: return LV_MemberFunction;
+  case Cl::CL_SubObjCPropertySetting: return LV_SubObjCPropertySetting;
+  case Cl::CL_ClassTemporary: return LV_ClassTemporary;
+  case Cl::CL_ArrayTemporary: return LV_ArrayTemporary;
+  case Cl::CL_ObjCMessageRValue: return LV_InvalidMessageExpression;
+  case Cl::CL_PRValue: return LV_InvalidExpression;
+  }
+  llvm_unreachable("Unhandled kind");
+}
+
+Expr::isModifiableLvalueResult
+Expr::isModifiableLvalue(ASTContext &Ctx, SourceLocation *Loc) const {
+  SourceLocation dummy;
+  Classification VC = ClassifyModifiable(Ctx, Loc ? *Loc : dummy);
+  switch (VC.getKind()) {
+  case Cl::CL_LValue: break;
+  case Cl::CL_XValue: return MLV_InvalidExpression;
+  case Cl::CL_Function: return MLV_NotObjectType;
+  case Cl::CL_Void: return MLV_InvalidExpression;
+  case Cl::CL_AddressableVoid: return MLV_IncompleteVoidType;
+  case Cl::CL_DuplicateVectorComponents: return MLV_DuplicateVectorComponents;
+  case Cl::CL_MemberFunction: return MLV_MemberFunction;
+  case Cl::CL_SubObjCPropertySetting: return MLV_SubObjCPropertySetting;
+  case Cl::CL_ClassTemporary: return MLV_ClassTemporary;
+  case Cl::CL_ArrayTemporary: return MLV_ArrayTemporary;
+  case Cl::CL_ObjCMessageRValue: return MLV_InvalidMessageExpression;
+  case Cl::CL_PRValue:
+    return VC.getModifiable() == Cl::CM_LValueCast ?
+      MLV_LValueCast : MLV_InvalidExpression;
+  }
+  assert(VC.getKind() == Cl::CL_LValue && "Unhandled kind");
+  switch (VC.getModifiable()) {
+  case Cl::CM_Untested: llvm_unreachable("Did not test modifiability");
+  case Cl::CM_Modifiable: return MLV_Valid;
+  case Cl::CM_RValue: llvm_unreachable("CM_RValue and CL_LValue don't match");
+  case Cl::CM_Function: return MLV_NotObjectType;
+  case Cl::CM_LValueCast:
+    llvm_unreachable("CM_LValueCast and CL_LValue don't match");
+  case Cl::CM_NoSetterProperty: return MLV_NoSetterProperty;
+  case Cl::CM_ConstQualified: return MLV_ConstQualified;
+  case Cl::CM_ConstQualifiedField: return MLV_ConstQualifiedField;
+  case Cl::CM_ConstAddrSpace: return MLV_ConstAddrSpace;
+  case Cl::CM_ArrayType: return MLV_ArrayType;
+  case Cl::CM_IncompleteType: return MLV_IncompleteType;
+  }
+  llvm_unreachable("Unhandled modifiable type");
+}