InterpreterValuePrinter.cpp

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//===--- InterpreterValuePrinter.cpp - Value printing utils -----*- C++ -*-===//
//
// 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 routines for in-process value printing in clang-repl.
//
//===----------------------------------------------------------------------===//
 
#include "IncrementalAction.h"
#include "InterpreterUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/PrettyPrinter.h"
#include "clang/AST/Type.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Interpreter/Interpreter.h"
#include "clang/Interpreter/Value.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Sema.h"
 
#include "llvm/Support/Error.h"
#include "llvm/Support/raw_ostream.h"
 
#include <cassert>
#include <cmath>
#include <cstdarg>
#include <sstream>
#include <string>
 
#define DEBUG_TYPE "interp-value"
 
using namespace clang;
 
static std::string DeclTypeToString(const QualType &QT, NamedDecl *D) {
  std::string Str;
  llvm::raw_string_ostream SS(Str);
  if (QT.hasQualifiers())
    SS << QT.getQualifiers().getAsString() << " ";
  SS << D->getQualifiedNameAsString();
  return Str;
}
 
static std::string QualTypeToString(ASTContext &Ctx, QualType QT) {
  PrintingPolicy Policy(Ctx.getPrintingPolicy());
  // Print the Allocator in STL containers, for instance.
  Policy.SuppressDefaultTemplateArgs = false;
  Policy.SuppressUnwrittenScope = true;
  // Print 'a<b<c> >' rather than 'a<b<c>>'.
  Policy.SplitTemplateClosers = true;
 
  struct LocalPrintingPolicyRAII {
    ASTContext &Context;
    PrintingPolicy Policy;
 
    LocalPrintingPolicyRAII(ASTContext &Ctx, PrintingPolicy &PP)
        : Context(Ctx), Policy(Ctx.getPrintingPolicy()) {
      Context.setPrintingPolicy(PP);
    }
    ~LocalPrintingPolicyRAII() { Context.setPrintingPolicy(Policy); }
  } X(Ctx, Policy);
 
  const QualType NonRefTy = QT.getNonReferenceType();
 
  if (const auto *TTy = llvm::dyn_cast<TagType>(NonRefTy))
    return DeclTypeToString(NonRefTy, TTy->getDecl());
 
  if (const auto *TRy = dyn_cast<RecordType>(NonRefTy))
    return DeclTypeToString(NonRefTy, TRy->getDecl());
 
  const QualType Canon = NonRefTy.getCanonicalType();
 
  // FIXME: How a builtin type can be a function pointer type?
  if (Canon->isBuiltinType() && !NonRefTy->isFunctionPointerType() &&
      !NonRefTy->isMemberPointerType())
    return Canon.getAsString(Ctx.getPrintingPolicy());
 
  if (const auto *TDTy = dyn_cast<TypedefType>(NonRefTy)) {
    // FIXME: TemplateSpecializationType & SubstTemplateTypeParmType checks
    // are predominately to get STL containers to print nicer and might be
    // better handled in GetFullyQualifiedName.
    //
    // std::vector<Type>::iterator is a TemplateSpecializationType
    // std::vector<Type>::value_type is a SubstTemplateTypeParmType
    //
    QualType SSDesugar = TDTy->getLocallyUnqualifiedSingleStepDesugaredType();
    if (llvm::isa<SubstTemplateTypeParmType>(SSDesugar))
      return GetFullTypeName(Ctx, Canon);
    else if (llvm::isa<TemplateSpecializationType>(SSDesugar))
      return GetFullTypeName(Ctx, NonRefTy);
    return DeclTypeToString(NonRefTy, TDTy->getDecl());
  }
  return GetFullTypeName(Ctx, NonRefTy);
}
 
static std::string EnumToString(const Value &V) {
  std::string Str;
  llvm::raw_string_ostream SS(Str);
  ASTContext &Ctx = const_cast<ASTContext &>(V.getASTContext());
 
  uint64_t Data = V.convertTo<uint64_t>();
  bool IsFirst = true;
  llvm::APSInt AP = Ctx.MakeIntValue(Data, V.getType());
 
  auto *ED = V.getType()->castAsEnumDecl();
  for (auto I = ED->enumerator_begin(), E = ED->enumerator_end(); I != E; ++I) {
    if (I->getInitVal() == AP) {
      if (!IsFirst)
        SS << " ? ";
      SS << "(" + I->getQualifiedNameAsString() << ")";
      IsFirst = false;
    }
  }
  llvm::SmallString<64> APStr;
  AP.toString(APStr, /*Radix=*/10);
  SS << " : " << QualTypeToString(Ctx, ED->getIntegerType()) << " " << APStr;
  return Str;
}
 
static std::string FunctionToString(const Value &V, const void *Ptr) {
  std::string Str;
  llvm::raw_string_ostream SS(Str);
  SS << "Function @" << Ptr;
 
  const DeclContext *PTU = V.getASTContext().getTranslationUnitDecl();
  // Find the last top-level-stmt-decl. This is a forward iterator but the
  // partial translation unit should not be large.
  const TopLevelStmtDecl *TLSD = nullptr;
  for (const Decl *D : PTU->noload_decls())
    if (isa<TopLevelStmtDecl>(D))
      TLSD = cast<TopLevelStmtDecl>(D);
 
  // Get __clang_Interpreter_SetValueNoAlloc(void *This, void *OutVal, void
  // *OpaqueType, void *Val);
  const FunctionDecl *FD = nullptr;
  if (auto *InterfaceCall = llvm::dyn_cast<CallExpr>(TLSD->getStmt())) {
    const auto *Arg = InterfaceCall->getArg(/*Val*/ 3);
    // Get rid of cast nodes.
    while (const CastExpr *CastE = llvm::dyn_cast<CastExpr>(Arg))
      Arg = CastE->getSubExpr();
    if (const DeclRefExpr *DeclRefExp = llvm::dyn_cast<DeclRefExpr>(Arg))
      FD = llvm::dyn_cast<FunctionDecl>(DeclRefExp->getDecl());
 
    if (FD) {
      SS << '\n';
      const clang::FunctionDecl *FDef;
      if (FD->hasBody(FDef))
        FDef->print(SS);
    }
  }
  return Str;
}
 
static std::string VoidPtrToString(const void *Ptr) {
  std::string Str;
  llvm::raw_string_ostream SS(Str);
  SS << Ptr;
  return Str;
}
 
static std::string CharPtrToString(const char *Ptr) {
  if (!Ptr)
    return "0";
 
  std::string Result = "\"";
  Result += Ptr;
  Result += '"';
  return Result;
}
 
namespace clang {
 
struct ValueRef : public Value {
  ValueRef(const Interpreter *In, void *Ty) : Value(In, Ty) {
    // Tell the base class to not try to deallocate if it manages the value.
    IsManuallyAlloc = false;
  }
};
 
std::string Interpreter::ValueDataToString(const Value &V) const {
  Sema &S = getCompilerInstance()->getSema();
  ASTContext &Ctx = S.getASTContext();
 
  QualType QT = V.getType();
 
  if (const ConstantArrayType *CAT = Ctx.getAsConstantArrayType(QT)) {
    QualType ElemTy = CAT->getElementType();
    size_t ElemCount = Ctx.getConstantArrayElementCount(CAT);
    const Type *BaseTy = CAT->getBaseElementTypeUnsafe();
    size_t ElemSize = Ctx.getTypeSizeInChars(BaseTy).getQuantity();
 
    // Treat null terminated char arrays as strings basically.
    if (ElemTy->isCharType()) {
      char last = *(char *)(((uintptr_t)V.getPtr()) + ElemCount * ElemSize - 1);
      if (last == '\0')
        return CharPtrToString((char *)V.getPtr());
    }
 
    std::string Result = "{ ";
    for (unsigned Idx = 0, N = CAT->getZExtSize(); Idx < N; ++Idx) {
      ValueRef InnerV = ValueRef(this, ElemTy.getAsOpaquePtr());
      if (ElemTy->isBuiltinType()) {
        // Single dim arrays, advancing.
        uintptr_t Offset = (uintptr_t)V.getPtr() + Idx * ElemSize;
        InnerV.setRawBits((void *)Offset, ElemSize * 8);
      } else {
        // Multi dim arrays, position to the next dimension.
        size_t Stride = ElemCount / N;
        uintptr_t Offset = ((uintptr_t)V.getPtr()) + Idx * Stride * ElemSize;
        InnerV.setPtr((void *)Offset);
      }
 
      Result += ValueDataToString(InnerV);
 
      // Skip the \0 if the char types
      if (Idx < N - 1)
        Result += ", ";
    }
    Result += " }";
    return Result;
  }
 
  QualType DesugaredTy = QT.getDesugaredType(Ctx);
  QualType NonRefTy = DesugaredTy.getNonReferenceType();
 
  // FIXME: Add support for user defined printers.
  // LookupResult R = LookupUserDefined(S, QT);
  // if (!R.empty())
  //   return CallUserSpecifiedPrinter(R, V);
 
  // If it is a builtin type dispatch to the builtin overloads.
  if (auto *BT = DesugaredTy.getCanonicalType()->getAs<BuiltinType>()) {
 
    auto formatFloating = [](auto Val, char Suffix = '\0') -> std::string {
      std::string Out;
      llvm::raw_string_ostream SS(Out);
 
      if (std::isnan(Val) || std::isinf(Val)) {
        SS << llvm::format("%g", Val);
        return SS.str();
      }
      if (Val == static_cast<decltype(Val)>(static_cast<int64_t>(Val)))
        SS << llvm::format("%.1f", Val);
      else if (std::abs(Val) < 1e-4 || std::abs(Val) > 1e6 || Suffix == 'f')
        SS << llvm::format("%#.6g", Val);
      else if (Suffix == 'L')
        SS << llvm::format("%#.12Lg", Val);
      else
        SS << llvm::format("%#.8g", Val);
 
      if (Suffix != '\0')
        SS << Suffix;
      return SS.str();
    };
 
    std::string Str;
    llvm::raw_string_ostream SS(Str);
    switch (BT->getKind()) {
    default:
      return "{ error: unknown builtin type '" + std::to_string(BT->getKind()) +
             " '}";
    case clang::BuiltinType::Bool:
      SS << ((V.getBool()) ? "true" : "false");
      return Str;
    case clang::BuiltinType::Char_S:
      SS << '\'' << V.getChar_S() << '\'';
      return Str;
    case clang::BuiltinType::SChar:
      SS << '\'' << V.getSChar() << '\'';
      return Str;
    case clang::BuiltinType::Char_U:
      SS << '\'' << V.getChar_U() << '\'';
      return Str;
    case clang::BuiltinType::UChar:
      SS << '\'' << V.getUChar() << '\'';
      return Str;
    case clang::BuiltinType::Short:
      SS << V.getShort();
      return Str;
    case clang::BuiltinType::UShort:
      SS << V.getUShort();
      return Str;
    case clang::BuiltinType::Int:
      SS << V.getInt();
      return Str;
    case clang::BuiltinType::UInt:
      SS << V.getUInt();
      return Str;
    case clang::BuiltinType::Long:
      SS << V.getLong();
      return Str;
    case clang::BuiltinType::ULong:
      SS << V.getULong();
      return Str;
    case clang::BuiltinType::LongLong:
      SS << V.getLongLong();
      return Str;
    case clang::BuiltinType::ULongLong:
      SS << V.getULongLong();
      return Str;
    case clang::BuiltinType::Float:
      return formatFloating(V.getFloat(), /*suffix=*/'f');
 
    case clang::BuiltinType::Double:
      return formatFloating(V.getDouble());
 
    case clang::BuiltinType::LongDouble:
      return formatFloating(V.getLongDouble(), /*suffix=*/'L');
    }
  }
 
  if ((NonRefTy->isPointerType() || NonRefTy->isMemberPointerType()) &&
      NonRefTy->getPointeeType()->isFunctionProtoType())
    return FunctionToString(V, V.getPtr());
 
  if (NonRefTy->isFunctionType())
    return FunctionToString(V, &V);
 
  if (NonRefTy->isEnumeralType())
    return EnumToString(V);
 
  if (NonRefTy->isNullPtrType())
    return "nullptr\n";
 
  // FIXME: Add support for custom printers in C.
  if (NonRefTy->isPointerType()) {
    if (NonRefTy->getPointeeType()->isCharType())
      return CharPtrToString((char *)V.getPtr());
 
    return VoidPtrToString(V.getPtr());
  }
 
  // Fall back to printing just the address of the unknown object.
  return "@" + VoidPtrToString(V.getPtr());
}
 
std::string Interpreter::ValueTypeToString(const Value &V) const {
  ASTContext &Ctx = const_cast<ASTContext &>(V.getASTContext());
  QualType QT = V.getType();
 
  std::string QTStr = QualTypeToString(Ctx, QT);
 
  if (QT->isReferenceType())
    QTStr += " &";
 
  return QTStr;
}
 
llvm::Expected<llvm::orc::ExecutorAddr>
Interpreter::CompileDtorCall(CXXRecordDecl *CXXRD) const {
  assert(CXXRD && "Cannot compile a destructor for a nullptr");
  if (auto Dtor = Dtors.find(CXXRD); Dtor != Dtors.end())
    return Dtor->getSecond();
 
  if (CXXRD->hasIrrelevantDestructor())
    return llvm::orc::ExecutorAddr{};
 
  CXXDestructorDecl *DtorRD =
      getCompilerInstance()->getSema().LookupDestructor(CXXRD);
 
  llvm::StringRef Name =
      Act->getCodeGen()->GetMangledName(GlobalDecl(DtorRD, Dtor_Base));
  auto AddrOrErr = getSymbolAddress(Name);
  if (!AddrOrErr)
    return AddrOrErr.takeError();
 
  Dtors[CXXRD] = *AddrOrErr;
  return AddrOrErr;
}
 
enum InterfaceKind { NoAlloc, WithAlloc, CopyArray, NewTag };
 
class InterfaceKindVisitor
    : public TypeVisitor<InterfaceKindVisitor, InterfaceKind> {
 
  Sema &S;
  Expr *E;
  llvm::SmallVectorImpl<Expr *> &Args;
 
public:
  InterfaceKindVisitor(Sema &S, Expr *E, llvm::SmallVectorImpl<Expr *> &Args)
      : S(S), E(E), Args(Args) {}
 
  InterfaceKind computeInterfaceKind(QualType Ty) {
    return Visit(Ty.getTypePtr());
  }
 
  InterfaceKind VisitRecordType(const RecordType *Ty) {
    return InterfaceKind::WithAlloc;
  }
 
  InterfaceKind VisitMemberPointerType(const MemberPointerType *Ty) {
    return InterfaceKind::WithAlloc;
  }
 
  InterfaceKind VisitConstantArrayType(const ConstantArrayType *Ty) {
    return InterfaceKind::CopyArray;
  }
 
  InterfaceKind VisitFunctionType(const FunctionType *Ty) {
    HandlePtrType(Ty);
    return InterfaceKind::NoAlloc;
  }
 
  InterfaceKind VisitPointerType(const PointerType *Ty) {
    HandlePtrType(Ty);
    return InterfaceKind::NoAlloc;
  }
 
  InterfaceKind VisitReferenceType(const ReferenceType *Ty) {
    ExprResult AddrOfE = S.CreateBuiltinUnaryOp(SourceLocation(), UO_AddrOf,
                                                E->IgnoreImpCasts());
    assert(!AddrOfE.isInvalid() && "Can not create unary expression");
    Args.push_back(AddrOfE.get());
    return InterfaceKind::NoAlloc;
  }
 
  InterfaceKind VisitBuiltinType(const BuiltinType *Ty) {
    if (Ty->isNullPtrType())
      Args.push_back(E);
    else if (Ty->isFloatingType())
      Args.push_back(E);
    else if (Ty->isIntegralOrEnumerationType())
      HandleIntegralOrEnumType(Ty);
    else if (Ty->isVoidType()) {
      // Do we need to still run `E`?
    }
 
    return InterfaceKind::NoAlloc;
  }
 
  InterfaceKind VisitEnumType(const EnumType *Ty) {
    HandleIntegralOrEnumType(Ty);
    return InterfaceKind::NoAlloc;
  }
 
private:
  // Force cast these types to the uint that fits the register size. That way we
  // reduce the number of overloads of `__clang_Interpreter_SetValueNoAlloc`.
  void HandleIntegralOrEnumType(const Type *Ty) {
    ASTContext &Ctx = S.getASTContext();
    uint64_t PtrBits = Ctx.getTypeSize(Ctx.VoidPtrTy);
    QualType UIntTy = Ctx.getBitIntType(/*Unsigned=*/true, PtrBits);
    TypeSourceInfo *TSI = Ctx.getTrivialTypeSourceInfo(UIntTy);
    ExprResult CastedExpr =
        S.BuildCStyleCastExpr(SourceLocation(), TSI, SourceLocation(), E);
    assert(!CastedExpr.isInvalid() && "Cannot create cstyle cast expr");
    Args.push_back(CastedExpr.get());
  }
 
  void HandlePtrType(const Type *Ty) {
    ASTContext &Ctx = S.getASTContext();
    TypeSourceInfo *TSI = Ctx.getTrivialTypeSourceInfo(Ctx.VoidPtrTy);
    ExprResult CastedExpr =
        S.BuildCStyleCastExpr(SourceLocation(), TSI, SourceLocation(), E);
    assert(!CastedExpr.isInvalid() && "Can not create cstyle cast expression");
    Args.push_back(CastedExpr.get());
  }
};
 
static constexpr llvm::StringRef VPName[] = {
    "__clang_Interpreter_SetValueNoAlloc",
    "__clang_Interpreter_SetValueWithAlloc",
    "__clang_Interpreter_SetValueCopyArr", "__ci_newtag"};
 
// This synthesizes a call expression to a speciall
// function that is responsible for generating the Value.
// In general, we transform c++:
//   clang-repl> x
// To:
//   // 1. If x is a built-in type like int, float.
//   __clang_Interpreter_SetValueNoAlloc(ThisInterp, OpaqueValue, xQualType, x);
//   // 2. If x is a struct, and a lvalue.
//   __clang_Interpreter_SetValueNoAlloc(ThisInterp, OpaqueValue, xQualType,
//   &x);
//   // 3. If x is a struct, but a rvalue.
//   new (__clang_Interpreter_SetValueWithAlloc(ThisInterp, OpaqueValue,
//   xQualType)) (x);
llvm::Expected<Expr *> Interpreter::convertExprToValue(Expr *E) {
  Sema &S = getCompilerInstance()->getSema();
  ASTContext &Ctx = S.getASTContext();
 
  // Find the value printing builtins.
  if (!ValuePrintingInfo[0]) {
    assert(llvm::all_of(ValuePrintingInfo, [](Expr *E) { return !E; }));
 
    auto LookupInterface = [&](Expr *&Interface,
                               llvm::StringRef Name) -> llvm::Error {
      LookupResult R(S, &Ctx.Idents.get(Name), SourceLocation(),
                     Sema::LookupOrdinaryName,
                     RedeclarationKind::ForVisibleRedeclaration);
      S.LookupQualifiedName(R, Ctx.getTranslationUnitDecl());
      if (R.empty())
        return llvm::make_error<llvm::StringError>(
            Name + " not found!", llvm::inconvertibleErrorCode());
 
      CXXScopeSpec CSS;
      Interface = S.BuildDeclarationNameExpr(CSS, R, /*ADL=*/false).get();
      return llvm::Error::success();
    };
    if (llvm::Error Err =
            LookupInterface(ValuePrintingInfo[NoAlloc], VPName[NoAlloc]))
      return std::move(Err);
 
    if (llvm::Error Err =
            LookupInterface(ValuePrintingInfo[CopyArray], VPName[CopyArray]))
      return std::move(Err);
 
    if (llvm::Error Err =
            LookupInterface(ValuePrintingInfo[WithAlloc], VPName[WithAlloc]))
      return std::move(Err);
 
    if (Ctx.getLangOpts().CPlusPlus) {
      if (llvm::Error Err =
              LookupInterface(ValuePrintingInfo[NewTag], VPName[NewTag]))
        return std::move(Err);
    }
  }
 
  llvm::SmallVector<Expr *, 4> AdjustedArgs;
  // Create parameter `ThisInterp`.
  AdjustedArgs.push_back(CStyleCastPtrExpr(S, Ctx.VoidPtrTy, (uintptr_t)this));
 
  // Create parameter `OutVal`.
  AdjustedArgs.push_back(
      CStyleCastPtrExpr(S, Ctx.VoidPtrTy, (uintptr_t)&LastValue));
 
  // Build `__clang_Interpreter_SetValue*` call.
 
  // Get rid of ExprWithCleanups.
  if (auto *EWC = llvm::dyn_cast_if_present<ExprWithCleanups>(E))
    E = EWC->getSubExpr();
 
  QualType Ty = E->IgnoreImpCasts()->getType();
  QualType DesugaredTy = Ty.getDesugaredType(Ctx);
 
  // For lvalue struct, we treat it as a reference.
  if (DesugaredTy->isRecordType() && E->IgnoreImpCasts()->isLValue()) {
    DesugaredTy = Ctx.getLValueReferenceType(DesugaredTy);
    Ty = Ctx.getLValueReferenceType(Ty);
  }
 
  Expr *TypeArg =
      CStyleCastPtrExpr(S, Ctx.VoidPtrTy, (uintptr_t)Ty.getAsOpaquePtr());
  // The QualType parameter `OpaqueType`, represented as `void*`.
  AdjustedArgs.push_back(TypeArg);
 
  // We push the last parameter based on the type of the Expr. Note we need
  // special care for rvalue struct.
  InterfaceKindVisitor V(S, E, AdjustedArgs);
  Scope *Scope = nullptr;
  ExprResult SetValueE;
  InterfaceKind Kind = V.computeInterfaceKind(DesugaredTy);
  switch (Kind) {
  case InterfaceKind::WithAlloc:
    [[fallthrough]];
  case InterfaceKind::CopyArray: {
    // __clang_Interpreter_SetValueWithAlloc.
    ExprResult AllocCall =
        S.ActOnCallExpr(Scope, ValuePrintingInfo[InterfaceKind::WithAlloc],
                        E->getBeginLoc(), AdjustedArgs, E->getEndLoc());
    if (AllocCall.isInvalid())
      return llvm::make_error<llvm::StringError>(
          "Cannot call to " + VPName[WithAlloc],
          llvm::inconvertibleErrorCode());
 
    TypeSourceInfo *TSI = Ctx.getTrivialTypeSourceInfo(Ty, SourceLocation());
 
    // Force CodeGen to emit destructor.
    if (auto *RD = Ty->getAsCXXRecordDecl()) {
      auto *Dtor = S.LookupDestructor(RD);
      Dtor->addAttr(UsedAttr::CreateImplicit(Ctx));
      getCompilerInstance()->getASTConsumer().HandleTopLevelDecl(
          DeclGroupRef(Dtor));
    }
 
    // __clang_Interpreter_SetValueCopyArr.
    if (Kind == InterfaceKind::CopyArray) {
      const auto *CATy = cast<ConstantArrayType>(DesugaredTy.getTypePtr());
      size_t ArrSize = Ctx.getConstantArrayElementCount(CATy);
 
      if (!Ctx.getLangOpts().CPlusPlus)
        ArrSize *= Ctx.getTypeSizeInChars(CATy->getBaseElementTypeUnsafe())
                       .getQuantity();
 
      Expr *ArrSizeExpr = IntegerLiteralExpr(Ctx, ArrSize);
      Expr *Args[] = {E, AllocCall.get(), ArrSizeExpr};
      SetValueE =
          S.ActOnCallExpr(Scope, ValuePrintingInfo[InterfaceKind::CopyArray],
                          SourceLocation(), Args, SourceLocation());
      if (SetValueE.isInvalid())
        return llvm::make_error<llvm::StringError>(
            "Cannot call to " + VPName[CopyArray],
            llvm::inconvertibleErrorCode());
      break;
    }
    Expr *Args[] = {AllocCall.get(), ValuePrintingInfo[InterfaceKind::NewTag]};
    ExprResult CXXNewCall = S.BuildCXXNew(
        E->getSourceRange(),
        /*UseGlobal=*/true, /*PlacementLParen=*/SourceLocation(), Args,
        /*PlacementRParen=*/SourceLocation(),
        /*TypeIdParens=*/SourceRange(), TSI->getType(), TSI, std::nullopt,
        E->getSourceRange(), E);
 
    if (CXXNewCall.isInvalid())
      return llvm::make_error<llvm::StringError>(
          "Cannot build a call to placement new",
          llvm::inconvertibleErrorCode());
 
    SetValueE = S.ActOnFinishFullExpr(CXXNewCall.get(),
                                      /*DiscardedValue=*/false);
    break;
  }
  // __clang_Interpreter_SetValueNoAlloc.
  case InterfaceKind::NoAlloc: {
    SetValueE =
        S.ActOnCallExpr(Scope, ValuePrintingInfo[InterfaceKind::NoAlloc],
                        E->getBeginLoc(), AdjustedArgs, E->getEndLoc());
    break;
  }
  default:
    llvm_unreachable("Unhandled InterfaceKind");
  }
 
  // It could fail, like printing an array type in C. (not supported)
  if (SetValueE.isInvalid())
    return E;
 
  return SetValueE.get();
}
 
} // namespace clang
 
using namespace clang;
 
// Temporary rvalue struct that need special care.
extern "C" {
REPL_EXTERNAL_VISIBILITY void *
__clang_Interpreter_SetValueWithAlloc(void *This, void *OutVal,
                                      void *OpaqueType) {
  Value &VRef = *(Value *)OutVal;
  VRef = Value(static_cast<Interpreter *>(This), OpaqueType);
  return VRef.getPtr();
}
 
REPL_EXTERNAL_VISIBILITY void
__clang_Interpreter_SetValueNoAlloc(void *This, void *OutVal, void *OpaqueType,
                                    ...) {
  Value &VRef = *(Value *)OutVal;
  Interpreter *I = static_cast<Interpreter *>(This);
  VRef = Value(I, OpaqueType);
  if (VRef.isVoid())
    return;
 
  va_list args;
  va_start(args, /*last named param*/ OpaqueType);
 
  QualType QT = VRef.getType();
  if (VRef.getKind() == Value::K_PtrOrObj) {
    VRef.setPtr(va_arg(args, void *));
  } else {
    if (const auto *ED = QT->getAsEnumDecl())
      QT = ED->getIntegerType();
    switch (QT->castAs<BuiltinType>()->getKind()) {
    default:
      llvm_unreachable("unknown type kind!");
      break;
      // Types shorter than int are resolved as int, else va_arg has UB.
    case BuiltinType::Bool:
      VRef.setBool(va_arg(args, int));
      break;
    case BuiltinType::Char_S:
      VRef.setChar_S(va_arg(args, int));
      break;
    case BuiltinType::SChar:
      VRef.setSChar(va_arg(args, int));
      break;
    case BuiltinType::Char_U:
      VRef.setChar_U(va_arg(args, unsigned));
      break;
    case BuiltinType::UChar:
      VRef.setUChar(va_arg(args, unsigned));
      break;
    case BuiltinType::Short:
      VRef.setShort(va_arg(args, int));
      break;
    case BuiltinType::UShort:
      VRef.setUShort(va_arg(args, unsigned));
      break;
    case BuiltinType::Int:
      VRef.setInt(va_arg(args, int));
      break;
    case BuiltinType::UInt:
      VRef.setUInt(va_arg(args, unsigned));
      break;
    case BuiltinType::Long:
      VRef.setLong(va_arg(args, long));
      break;
    case BuiltinType::ULong:
      VRef.setULong(va_arg(args, unsigned long));
      break;
    case BuiltinType::LongLong:
      VRef.setLongLong(va_arg(args, long long));
      break;
    case BuiltinType::ULongLong:
      VRef.setULongLong(va_arg(args, unsigned long long));
      break;
      // Types shorter than double are resolved as double, else va_arg has UB.
    case BuiltinType::Float:
      VRef.setFloat(va_arg(args, double));
      break;
    case BuiltinType::Double:
      VRef.setDouble(va_arg(args, double));
      break;
    case BuiltinType::LongDouble:
      VRef.setLongDouble(va_arg(args, long double));
      break;
      // See REPL_BUILTIN_TYPES.
    }
  }
  va_end(args);
}
}
 
// A trampoline to work around the fact that operator placement new cannot
// really be forward declared due to libc++ and libstdc++ declaration mismatch.
// FIXME: __clang_Interpreter_NewTag is ODR violation because we get the same
// definition in the interpreter runtime. We should move it in a runtime header
// which gets included by the interpreter and here.
struct __clang_Interpreter_NewTag {};
REPL_EXTERNAL_VISIBILITY void *
operator new(size_t __sz, void *__p, __clang_Interpreter_NewTag) noexcept {
  // Just forward to the standard operator placement new.
  return operator new(__sz, __p);
}