InterpHelpers.h

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//===--- InterpHelpers.h - Interpreter Helper Functions --------*- 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
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_CLANG_AST_INTERP_INTERPHELPERS_H
#define LLVM_CLANG_AST_INTERP_INTERPHELPERS_H
 
#include "DynamicAllocator.h"
#include "InterpState.h"
#include "Pointer.h"
 
namespace clang {
class CallExpr;
class OffsetOfExpr;
 
namespace interp {
class Block;
struct Descriptor;
 
/// Interpreter entry point.
bool Interpret(InterpState &S);
 
/// Interpret a builtin function.
bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call,
                      uint32_t BuiltinID);
 
/// Interpret an offsetof operation.
bool InterpretOffsetOf(InterpState &S, CodePtr OpPC, const OffsetOfExpr *E,
                       ArrayRef<int64_t> ArrayIndices, int64_t &Result);
 
/// Checks if the array is offsetable.
bool CheckArray(InterpState &S, CodePtr OpPC, const Pointer &Ptr);
 
/// Checks if a pointer is live and accessible.
bool CheckLive(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
               AccessKinds AK);
 
/// Checks if a pointer is a dummy pointer.
bool CheckDummy(InterpState &S, CodePtr OpPC, const Block *B, AccessKinds AK);
 
/// Checks if a pointer is in range.
template <typename T>
bool CheckRange(InterpState &S, CodePtr OpPC, T Ptr, AccessKinds AK) {
  if (!Ptr.isOnePastEnd() && !Ptr.isZeroSizeArray())
    return true;
  if (S.getLangOpts().CPlusPlus) {
    const SourceInfo &Loc = S.Current->getSource(OpPC);
    S.FFDiag(Loc, diag::note_constexpr_access_past_end)
        << AK << S.Current->getRange(OpPC);
  }
  return false;
}
 
/// Checks if a field from which a pointer is going to be derived is valid.
bool CheckRange(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
                CheckSubobjectKind CSK);
 
/// Checks if a pointer points to a mutable field.
bool CheckMutable(InterpState &S, CodePtr OpPC, PtrView Ptr,
                  AccessKinds AK = AK_Read);
inline bool CheckMutable(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
                         AccessKinds AK = AK_Read) {
  if (!Ptr.isBlockPointer())
    return true;
  return CheckMutable(S, OpPC, Ptr.view(), AK);
}
 
/// Checks if a value can be loaded from a block.
bool CheckLoad(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
               AccessKinds AK = AK_Read);
 
/// Diagnose mismatched new[]/delete or new/delete[] pairs.
bool CheckNewDeleteForms(InterpState &S, CodePtr OpPC,
                         DynamicAllocator::Form AllocForm,
                         DynamicAllocator::Form DeleteForm, const Descriptor *D,
                         const Expr *NewExpr);
 
/// Copy the contents of Src into Dest.
bool DoMemcpy(InterpState &S, CodePtr OpPC, const Pointer &Src, Pointer &Dest);
 
UnsignedOrNone evaluateBuiltinObjectSize(const ASTContext &ASTCtx,
                                         unsigned Kind, Pointer &Ptr);
 
template <typename T>
bool handleOverflow(InterpState &S, CodePtr OpPC, const T &SrcValue) {
  const Expr *E = S.Current->getExpr(OpPC);
  S.CCEDiag(E, diag::note_constexpr_overflow) << SrcValue << E->getType();
  return S.noteUndefinedBehavior();
}
 
inline bool CheckArraySize(InterpState &S, CodePtr OpPC, uint64_t NumElems) {
  uint64_t Limit = S.getLangOpts().ConstexprStepLimit;
  if (Limit != 0 && NumElems > Limit) {
    S.FFDiag(S.Current->getSource(OpPC),
             diag::note_constexpr_new_exceeds_limits, 1)
        << NumElems << Limit;
    S.Note(S.Current->getSource(OpPC), diag::note_constexpr_steps);
    return false;
  }
  return true;
}
 
static inline llvm::RoundingMode getRoundingMode(FPOptions FPO) {
  auto RM = FPO.getRoundingMode();
  if (RM == llvm::RoundingMode::Dynamic)
    return llvm::RoundingMode::NearestTiesToEven;
  return RM;
}
 
inline bool Invalid(InterpState &S, CodePtr OpPC) {
  const SourceLocation &Loc = S.Current->getLocation(OpPC);
  S.FFDiag(Loc, diag::note_invalid_subexpr_in_const_expr)
      << S.Current->getRange(OpPC);
  return false;
}
 
template <typename SizeT>
bool CheckArraySize(InterpState &S, CodePtr OpPC, SizeT *NumElements,
                    unsigned ElemSize, bool IsNoThrow) {
 
  if (ElemSize == 0)
    return true;
 
  // FIXME: Both the SizeT::from() as well as the
  // NumElements.toAPSInt() in this function are rather expensive.
 
  // Can't be too many elements if the bitwidth of NumElements is lower than
  // that of Descriptor::MaxArrayElemBytes.
  if ((NumElements->bitWidth() - NumElements->isSigned()) <
      (sizeof(Descriptor::MaxArrayElemBytes) * 8))
    return true;
 
  // FIXME: GH63562
  // APValue stores array extents as unsigned,
  // so anything that is greater that unsigned would overflow when
  // constructing the array, we catch this here.
  SizeT MaxElements = SizeT::from(Descriptor::MaxArrayElemBytes / ElemSize);
  assert(MaxElements.isPositive());
  if (NumElements->toAPSInt().getActiveBits() >
          ConstantArrayType::getMaxSizeBits(S.getASTContext()) ||
      *NumElements > MaxElements) {
    if (!IsNoThrow) {
      const SourceInfo &Loc = S.Current->getSource(OpPC);
 
      if (NumElements->isSigned() && NumElements->isNegative()) {
        S.FFDiag(Loc, diag::note_constexpr_new_negative)
            << NumElements->toDiagnosticString(S.getASTContext());
      } else {
        S.FFDiag(Loc, diag::note_constexpr_new_too_large)
            << NumElements->toDiagnosticString(S.getASTContext());
      }
    }
    return false;
  }
  return true;
}
 
} // namespace interp
} // namespace clang
 
#endif // LLVM_CLANG_AST_INTERP_INTERPHELPERS_H