SemaBoundsSafety.cpp

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//===-- SemaBoundsSafety.cpp - Bounds Safety specific routines-*- 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
//
//===----------------------------------------------------------------------===//
/// \file
/// This file declares semantic analysis functions specific to `-fbounds-safety`
/// (Bounds Safety) and also its attributes when used without `-fbounds-safety`
/// (e.g. `counted_by`)
///
//===----------------------------------------------------------------------===//
#include "clang/Sema/Sema.h"
 
namespace clang {
 
static CountAttributedType::DynamicCountPointerKind
getCountAttrKind(bool CountInBytes, bool OrNull) {
  if (CountInBytes)
    return OrNull ? CountAttributedType::SizedByOrNull
                  : CountAttributedType::SizedBy;
  return OrNull ? CountAttributedType::CountedByOrNull
                : CountAttributedType::CountedBy;
}
 
static const RecordDecl *GetEnclosingNamedOrTopAnonRecord(const FieldDecl *FD) {
  const auto *RD = FD->getParent();
  // An unnamed struct is anonymous struct only if it's not instantiated.
  // However, the struct may not be fully processed yet to determine
  // whether it's anonymous or not. In that case, this function treats it as
  // an anonymous struct and tries to find a named parent.
  while (RD && (RD->isAnonymousStructOrUnion() ||
                (!RD->isCompleteDefinition() && RD->getName().empty()))) {
    const auto *Parent = dyn_cast<RecordDecl>(RD->getParent());
    if (!Parent)
      break;
    RD = Parent;
  }
  return RD;
}
 
enum class CountedByInvalidPointeeTypeKind {
  INCOMPLETE,
  SIZELESS,
  FUNCTION,
  FLEXIBLE_ARRAY_MEMBER,
  VALID,
};
 
bool Sema::CheckCountedByAttrOnField(FieldDecl *FD, Expr *E, bool CountInBytes,
                                     bool OrNull) {
  // Check the context the attribute is used in
 
  unsigned Kind = getCountAttrKind(CountInBytes, OrNull);
 
  if (FD->getParent()->isUnion()) {
    Diag(FD->getBeginLoc(), diag::err_count_attr_in_union)
        << Kind << FD->getSourceRange();
    return true;
  }
 
  const auto FieldTy = FD->getType();
  if (FieldTy->isArrayType() && (CountInBytes || OrNull)) {
    Diag(FD->getBeginLoc(),
         diag::err_count_attr_not_on_ptr_or_flexible_array_member)
        << Kind << FD->getLocation() << /* suggest counted_by */ 1;
    return true;
  }
  if (!FieldTy->isArrayType() && !FieldTy->isPointerType()) {
    Diag(FD->getBeginLoc(),
         diag::err_count_attr_not_on_ptr_or_flexible_array_member)
        << Kind << FD->getLocation() << /* do not suggest counted_by */ 0;
    return true;
  }
 
  LangOptions::StrictFlexArraysLevelKind StrictFlexArraysLevel =
      LangOptions::StrictFlexArraysLevelKind::IncompleteOnly;
  if (FieldTy->isArrayType() &&
      !Decl::isFlexibleArrayMemberLike(getASTContext(), FD, FieldTy,
                                       StrictFlexArraysLevel, true)) {
    Diag(FD->getBeginLoc(),
         diag::err_counted_by_attr_on_array_not_flexible_array_member)
        << Kind << FD->getLocation();
    return true;
  }
 
  CountedByInvalidPointeeTypeKind InvalidTypeKind =