lib/AST/APValue.cpp

//===--- APValue.cpp - Union class for APFloat/APSInt/Complex -------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements the APValue class.
//
//===----------------------------------------------------------------------===//

#include "clang/AST/APValue.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Type.h"
#include "clang/Basic/Diagnostic.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/ErrorHandling.h"
using namespace clang;

namespace {
  struct LVBase {
    llvm::PointerIntPair<APValue::LValueBase, 1, bool> BaseAndIsOnePastTheEnd;
    CharUnits Offset;
    unsigned PathLength;
  };
}

struct APValue::LV : LVBase {
  static const unsigned InlinePathSpace =
      (MaxSize - sizeof(LVBase)) / sizeof(LValuePathEntry);

  /// Path - The sequence of base classes, fields and array indices to follow to
  /// walk from Base to the subobject. When performing GCC-style folding, there
  /// may not be such a path.
  union {
    LValuePathEntry Path[InlinePathSpace];
    LValuePathEntry *PathPtr;
  };

  LV() { PathLength = (unsigned)-1; }
  ~LV() { resizePath(0); }

  void resizePath(unsigned Length) {
    if (Length == PathLength)
      return;
    if (hasPathPtr())
      delete [] PathPtr;
    PathLength = Length;
    if (hasPathPtr())
      PathPtr = new LValuePathEntry[Length];
  }

  bool hasPath() const { return PathLength != (unsigned)-1; }
  bool hasPathPtr() const { return hasPath() && PathLength > InlinePathSpace; }

  LValuePathEntry *getPath() { return hasPathPtr() ? PathPtr : Path; }
  const LValuePathEntry *getPath() const {
    return hasPathPtr() ? PathPtr : Path;
  }
};

namespace {
  struct MemberPointerBase {
    llvm::PointerIntPair<const ValueDecl*, 1, bool> MemberAndIsDerivedMember;
    unsigned PathLength;
  };
}

struct APValue::MemberPointerData : MemberPointerBase {
  static const unsigned InlinePathSpace =
      (MaxSize - sizeof(MemberPointerBase)) / sizeof(const CXXRecordDecl*);
  typedef const CXXRecordDecl *PathElem;
  union {
    PathElem Path[InlinePathSpace];
    PathElem *PathPtr;
  };

  MemberPointerData() { PathLength = 0; }
  ~MemberPointerData() { resizePath(0); }

  void resizePath(unsigned Length) {
    if (Length == PathLength)
      return;
    if (hasPathPtr())
      delete [] PathPtr;
    PathLength = Length;
    if (hasPathPtr())
      PathPtr = new PathElem[Length];
  }

  bool hasPathPtr() const { return PathLength > InlinePathSpace; }

  PathElem *getPath() { return hasPathPtr() ? PathPtr : Path; }
  const PathElem *getPath() const {
    return hasPathPtr() ? PathPtr : Path;
  }
};

// FIXME: Reduce the malloc traffic here.

APValue::Arr::Arr(unsigned NumElts, unsigned Size) :
  Elts(new APValue[NumElts + (NumElts != Size ? 1 : 0)]),
  NumElts(NumElts), ArrSize(Size) {}
APValue::Arr::~Arr() { delete [] Elts; }

APValue::StructData::StructData(unsigned NumBases, unsigned NumFields) :
  Elts(new APValue[NumBases+NumFields]),
  NumBases(NumBases), NumFields(NumFields) {}
APValue::StructData::~StructData() {
  delete [] Elts;
}

APValue::UnionData::UnionData() : Field(0), Value(new APValue) {}
APValue::UnionData::~UnionData () {
  delete Value;
}

const APValue &APValue::operator=(const APValue &RHS) {
  if (this == &RHS)
    return *this;
  if (Kind != RHS.Kind || Kind == Array || Kind == Struct ||
      Kind == MemberPointer) {
    MakeUninit();
    if (RHS.isInt())
      MakeInt();
    else if (RHS.isFloat())
      MakeFloat();
    else if (RHS.isVector())
      MakeVector();
    else if (RHS.isComplexInt())
      MakeComplexInt();
    else if (RHS.isComplexFloat())
      MakeComplexFloat();
    else if (RHS.isLValue())
      MakeLValue();
    else if (RHS.isArray())
      MakeArray(RHS.getArrayInitializedElts(), RHS.getArraySize());
    else if (RHS.isStruct())
      MakeStruct(RHS.getStructNumBases(), RHS.getStructNumFields());
    else if (RHS.isUnion())
      MakeUnion();
    else if (RHS.isMemberPointer())
      MakeMemberPointer(RHS.getMemberPointerDecl(),
                        RHS.isMemberPointerToDerivedMember(),
                        RHS.getMemberPointerPath());
  }
  if (isInt())
    setInt(RHS.getInt());
  else if (isFloat())
    setFloat(RHS.getFloat());
  else if (isVector())
    setVector(((const Vec *)(const char *)RHS.Data)->Elts,
              RHS.getVectorLength());
  else if (isComplexInt())
    setComplexInt(RHS.getComplexIntReal(), RHS.getComplexIntImag());
  else if (isComplexFloat())
    setComplexFloat(RHS.getComplexFloatReal(), RHS.getComplexFloatImag());
  else if (isLValue()) {
    if (RHS.hasLValuePath())
      setLValue(RHS.getLValueBase(), RHS.getLValueOffset(), RHS.getLValuePath(),
                RHS.isLValueOnePastTheEnd());
    else
      setLValue(RHS.getLValueBase(), RHS.getLValueOffset(), NoLValuePath());
  } else if (isArray()) {
    for (unsigned I = 0, N = RHS.getArrayInitializedElts(); I != N; ++I)
      getArrayInitializedElt(I) = RHS.getArrayInitializedElt(I);
    if (RHS.hasArrayFiller())
      getArrayFiller() = RHS.getArrayFiller();
  } else if (isStruct()) {
    for (unsigned I = 0, N = RHS.getStructNumBases(); I != N; ++I)
      getStructBase(I) = RHS.getStructBase(I);
    for (unsigned I = 0, N = RHS.getStructNumFields(); I != N; ++I)
      getStructField(I) = RHS.getStructField(I);
  } else if (isUnion())
    setUnion(RHS.getUnionField(), RHS.getUnionValue());
  return *this;
}

void APValue::MakeUninit() {
  if (Kind == Int)
    ((APSInt*)(char*)Data)->~APSInt();
  else if (Kind == Float)
    ((APFloat*)(char*)Data)->~APFloat();
  else if (Kind == Vector)
    ((Vec*)(char*)Data)->~Vec();
  else if (Kind == ComplexInt)
    ((ComplexAPSInt*)(char*)Data)->~ComplexAPSInt();
  else if (Kind == ComplexFloat)
    ((ComplexAPFloat*)(char*)Data)->~ComplexAPFloat();
  else if (Kind == LValue)
    ((LV*)(char*)Data)->~LV();
  else if (Kind == Array)
    ((Arr*)(char*)Data)->~Arr();
  else if (Kind == Struct)
    ((StructData*)(char*)Data)->~StructData();
  else if (Kind == Union)
    ((UnionData*)(char*)Data)->~UnionData();
  else if (Kind == MemberPointer)
    ((MemberPointerData*)(char*)Data)->~MemberPointerData();
  Kind = Uninitialized;
}

void APValue::dump() const {
  dump(llvm::errs());
  llvm::errs() << '\n';
}

static double GetApproxValue(const llvm::APFloat &F) {
  llvm::APFloat V = F;
  bool ignored;
  V.convert(llvm::APFloat::IEEEdouble, llvm::APFloat::rmNearestTiesToEven,
            &ignored);
  return V.convertToDouble();
}

void APValue::dump(raw_ostream &OS) const {
  switch (getKind()) {
  case Uninitialized:
    OS << "Uninitialized";
    return;
  case Int:
    OS << "Int: " << getInt();
    return;
  case Float:
    OS << "Float: " << GetApproxValue(getFloat());
    return;
  case Vector:
    OS << "Vector: ";
    getVectorElt(0).dump(OS);
    for (unsigned i = 1; i != getVectorLength(); ++i) {
      OS << ", ";
      getVectorElt(i).dump(OS);
    }
    return;
  case ComplexInt:
    OS << "ComplexInt: " << getComplexIntReal() << ", " << getComplexIntImag();
    return;
  case ComplexFloat:
    OS << "ComplexFloat: " << GetApproxValue(getComplexFloatReal())
       << ", " << GetApproxValue(getComplexFloatImag());
    return;
  case LValue:
    OS << "LValue: <todo>";
    return;
  case Array:
    OS << "Array: ";
    for (unsigned I = 0, N = getArrayInitializedElts(); I != N; ++I) {
      getArrayInitializedElt(I).dump(OS);
      if (I != getArraySize() - 1) OS << ", ";
    }
    if (hasArrayFiller()) {
      OS << getArraySize() - getArrayInitializedElts() << " x ";
      getArrayFiller().dump(OS);
    }
    return;
  case Struct:
    OS << "Struct ";
    if (unsigned N = getStructNumBases()) {
      OS << " bases: ";
      getStructBase(0).dump(OS);
      for (unsigned I = 1; I != N; ++I) {
        OS << ", ";
        getStructBase(I).dump(OS);
      }
    }
    if (unsigned N = getStructNumFields()) {
      OS << " fields: ";
      getStructField(0).dump(OS);
      for (unsigned I = 1; I != N; ++I) {
        OS << ", ";
        getStructField(I).dump(OS);
      }
    }
    return;
  case Union:
    OS << "Union: ";
    getUnionValue().dump(OS);
    return;
  case MemberPointer:
    OS << "MemberPointer: <todo>";
    return;
  }
  llvm_unreachable("Unknown APValue kind!");
}

void APValue::printPretty(raw_ostream &Out, ASTContext &Ctx, QualType Ty) const{
  switch (getKind()) {
  case APValue::Uninitialized:
    Out << "<uninitialized>";
    return;
  case APValue::Int:
    Out << getInt();
    return;
  case APValue::Float:
    Out << GetApproxValue(getFloat());
    return;
  case APValue::Vector: {
    Out << '{';
    QualType ElemTy = Ty->getAs<VectorType>()->getElementType();
    getVectorElt(0).printPretty(Out, Ctx, ElemTy);
    for (unsigned i = 1; i != getVectorLength(); ++i) {
      Out << ", ";
      getVectorElt(i).printPretty(Out, Ctx, ElemTy);
    }
    Out << '}';
    return;
  }
  case APValue::ComplexInt:
    Out << getComplexIntReal() << "+" << getComplexIntImag() << "i";
    return;
  case APValue::ComplexFloat:
    Out << GetApproxValue(getComplexFloatReal()) << "+"
        << GetApproxValue(getComplexFloatImag()) << "i";
    return;
  case APValue::LValue: {
    LValueBase Base = getLValueBase();
    if (!Base) {
      Out << "0";
      return;
    }

    bool IsReference = Ty->isReferenceType();
    QualType InnerTy
      = IsReference ? Ty.getNonReferenceType() : Ty->getPointeeType();

    if (!hasLValuePath()) {
      // No lvalue path: just print the offset.
      CharUnits O = getLValueOffset();
      CharUnits S = Ctx.getTypeSizeInChars(InnerTy);
      if (!O.isZero()) {
        if (IsReference)
          Out << "*(";
        if (O % S) {
          Out << "(char*)";
          S = CharUnits::One();
        }
        Out << '&';
      } else if (!IsReference)
        Out << '&';

      if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
        Out << *VD;
      else
        Base.get<const Expr*>()->printPretty(Out, Ctx, 0,
                                             Ctx.getPrintingPolicy());
      if (!O.isZero()) {
        Out << " + " << (O / S);
        if (IsReference)
          Out << ')';
      }
      return;
    }

    // We have an lvalue path. Print it out nicely.
    if (!IsReference)
      Out << '&';
    else if (isLValueOnePastTheEnd())
      Out << "*(&";

    QualType ElemTy;
    if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
      Out << *VD;
      ElemTy = VD->getType();
    } else {
      const Expr *E = Base.get<const Expr*>();
      E->printPretty(Out, Ctx, 0,Ctx.getPrintingPolicy());
      ElemTy = E->getType();
    }

    ArrayRef<LValuePathEntry> Path = getLValuePath();
    const CXXRecordDecl *CastToBase = 0;
    for (unsigned I = 0, N = Path.size(); I != N; ++I) {
      if (ElemTy->getAs<RecordType>()) {
        // The lvalue refers to a class type, so the next path entry is a base
        // or member.
        const Decl *BaseOrMember =
        BaseOrMemberType::getFromOpaqueValue(Path[I].BaseOrMember).getPointer();
        if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(BaseOrMember)) {
          CastToBase = RD;
          ElemTy = Ctx.getRecordType(RD);
        } else {
          const ValueDecl *VD = cast<ValueDecl>(BaseOrMember);
          Out << ".";
          if (CastToBase)
            Out << *CastToBase << "::";
          Out << *VD;
          ElemTy = VD->getType();
        }
      } else {
        // The lvalue must refer to an array.
        Out << '[' << Path[I].ArrayIndex << ']';
        ElemTy = Ctx.getAsArrayType(ElemTy)->getElementType();
      }
    }

    // Handle formatting of one-past-the-end lvalues.
    if (isLValueOnePastTheEnd()) {
      // FIXME: If CastToBase is non-0, we should prefix the output with
      // "(CastToBase*)".
      Out << " + 1";
      if (IsReference)
        Out << ')';
    }
    return;
  }
  case APValue::Array: {
    const ArrayType *AT = Ctx.getAsArrayType(Ty);
    QualType ElemTy = AT->getElementType();
    Out << '{';
    if (unsigned N = getArrayInitializedElts()) {
      getArrayInitializedElt(0).printPretty(Out, Ctx, ElemTy);
      for (unsigned I = 1; I != N; ++I) {
        Out << ", ";
        if (I == 10) {
          // Avoid printing out the entire contents of large arrays.
          Out << "...";
          break;
        }
        getArrayInitializedElt(I).printPretty(Out, Ctx, ElemTy);
      }
    }
    Out << '}';
    return;
  }
  case APValue::Struct: {
    Out << '{';
    const RecordDecl *RD = Ty->getAs<RecordType>()->getDecl();
    bool First = true;
    if (unsigned N = getStructNumBases()) {
      const CXXRecordDecl *CD = cast<CXXRecordDecl>(RD);
      CXXRecordDecl::base_class_const_iterator BI = CD->bases_begin();
      for (unsigned I = 0; I != N; ++I, ++BI) {
        assert(BI != CD->bases_end());
        if (!First)
          Out << ", ";
        getStructBase(I).printPretty(Out, Ctx, BI->getType());
        First = false;
      }
    }
    for (RecordDecl::field_iterator FI = RD->field_begin();
         FI != RD->field_end(); ++FI) {
      if (!First)
        Out << ", ";
      if ((*FI)->isUnnamedBitfield()) continue;
      getStructField((*FI)->getFieldIndex()).
        printPretty(Out, Ctx, (*FI)->getType());
      First = false;
    }
    Out << '}';
    return;
  }
  case APValue::Union:
    Out << '{';
    if (const FieldDecl *FD = getUnionField()) {
      Out << "." << *FD << " = ";
      getUnionValue().printPretty(Out, Ctx, FD->getType());
    }
    Out << '}';
    return;
  case APValue::MemberPointer:
    // FIXME: This is not enough to unambiguously identify the member in a
    // multiple-inheritance scenario.
    if (const ValueDecl *VD = getMemberPointerDecl()) {
      Out << '&' << *cast<CXXRecordDecl>(VD->getDeclContext()) << "::" << *VD;
      return;
    }
    Out << "0";
    return;
  }
  llvm_unreachable("Unknown APValue kind!");
}

std::string APValue::getAsString(ASTContext &Ctx, QualType Ty) const {
  std::string Result;
  llvm::raw_string_ostream Out(Result);
  printPretty(Out, Ctx, Ty);
  Out.flush();
  return Result;
}

const APValue::LValueBase APValue::getLValueBase() const {
  assert(isLValue() && "Invalid accessor");
  return ((const LV*)(const void*)Data)->BaseAndIsOnePastTheEnd.getPointer();
}

bool APValue::isLValueOnePastTheEnd() const {
  assert(isLValue() && "Invalid accessor");
  return ((const LV*)(const void*)Data)->BaseAndIsOnePastTheEnd.getInt();
}

CharUnits &APValue::getLValueOffset() {
  assert(isLValue() && "Invalid accessor");
  return ((LV*)(void*)Data)->Offset;
}

bool APValue::hasLValuePath() const {
  assert(isLValue() && "Invalid accessor");
  return ((const LV*)(const char*)Data)->hasPath();
}

ArrayRef<APValue::LValuePathEntry> APValue::getLValuePath() const {
  assert(isLValue() && hasLValuePath() && "Invalid accessor");
  const LV &LVal = *((const LV*)(const char*)Data);
  return ArrayRef<LValuePathEntry>(LVal.getPath(), LVal.PathLength);
}

void APValue::setLValue(LValueBase B, const CharUnits &O, NoLValuePath) {
  assert(isLValue() && "Invalid accessor");
  LV &LVal = *((LV*)(char*)Data);
  LVal.BaseAndIsOnePastTheEnd.setPointer(B);
  LVal.BaseAndIsOnePastTheEnd.setInt(false);
  LVal.Offset = O;
  LVal.resizePath((unsigned)-1);
}

void APValue::setLValue(LValueBase B, const CharUnits &O,
                        ArrayRef<LValuePathEntry> Path, bool IsOnePastTheEnd) {
  assert(isLValue() && "Invalid accessor");
  LV &LVal = *((LV*)(char*)Data);
  LVal.BaseAndIsOnePastTheEnd.setPointer(B);
  LVal.BaseAndIsOnePastTheEnd.setInt(IsOnePastTheEnd);
  LVal.Offset = O;
  LVal.resizePath(Path.size());
  memcpy(LVal.getPath(), Path.data(), Path.size() * sizeof(LValuePathEntry));
}

const ValueDecl *APValue::getMemberPointerDecl() const {
  assert(isMemberPointer() && "Invalid accessor");
  const MemberPointerData &MPD = *((const MemberPointerData*)(const char*)Data);
  return MPD.MemberAndIsDerivedMember.getPointer();
}

bool APValue::isMemberPointerToDerivedMember() const {
  assert(isMemberPointer() && "Invalid accessor");
  const MemberPointerData &MPD = *((const MemberPointerData*)(const char*)Data);
  return MPD.MemberAndIsDerivedMember.getInt();
}

ArrayRef<const CXXRecordDecl*> APValue::getMemberPointerPath() const {
  assert(isMemberPointer() && "Invalid accessor");
  const MemberPointerData &MPD = *((const MemberPointerData*)(const char*)Data);
  return ArrayRef<const CXXRecordDecl*>(MPD.getPath(), MPD.PathLength);
}

void APValue::MakeLValue() {
  assert(isUninit() && "Bad state change");
  assert(sizeof(LV) <= MaxSize && "LV too big");
  new ((void*)(char*)Data) LV();
  Kind = LValue;
}

void APValue::MakeArray(unsigned InitElts, unsigned Size) {
  assert(isUninit() && "Bad state change");
  new ((void*)(char*)Data) Arr(InitElts, Size);
  Kind = Array;
}

void APValue::MakeMemberPointer(const ValueDecl *Member, bool IsDerivedMember,
                                ArrayRef<const CXXRecordDecl*> Path) {
  assert(isUninit() && "Bad state change");
  MemberPointerData *MPD = new ((void*)(char*)Data) MemberPointerData;
  Kind = MemberPointer;
  MPD->MemberAndIsDerivedMember.setPointer(Member);
  MPD->MemberAndIsDerivedMember.setInt(IsDerivedMember);
  MPD->resizePath(Path.size());
  memcpy(MPD->getPath(), Path.data(), Path.size()*sizeof(const CXXRecordDecl*));
}