revng-revng/lib/Model/Importer/Binary/SegmentImportHelpers.h

#pragma once

//
// This file is distributed under the MIT License. See LICENSE.md for details.
//

#include "revng/Model/Binary.h"
#include "revng/Model/IRHelpers.h"
#include "revng/Support/Assert.h"
#include "revng/Support/IRHelpers.h"
#include "revng/Support/MetaAddress.h"

struct DataSymbol {
  MetaAddress Address;
  uint64_t Size;
  llvm::StringRef Name;

  DataSymbol(MetaAddress Address, uint64_t Size, llvm::StringRef Name) :
    Address(Address), Size(Size), Name(Name) {}

  bool operator==(const DataSymbol &) const = default;
};

inline bool checkForOverlap(const model::StructDefinition &Struct,
                            uint64_t Offset,
                            uint64_t Size) {
  for (auto &Current : Struct.Fields()) {
    uint64_t CurrentSize = *Current.Type()->size();
    if ((Current.Offset() < Offset + Size))
      if (Current.Offset() + CurrentSize > Offset)
        return true;
  }

  return false;
}

inline void importSymbolsInto(model::Binary &Binary,
                              llvm::SmallVector<DataSymbol, 32> &DataSymbols,
                              model::StructDefinition &Struct,
                              MetaAddress StructStartAddress) {
  MetaAddress StructEndAddress = StructStartAddress + Struct.Size();
  if (not StructEndAddress.isValid())
    return;

  for (auto It = DataSymbols.begin(); It != DataSymbols.end(); ++It) {
    const auto &[SymbolStartAddress, SymbolSize, SymbolName] = *It;
    MetaAddress SymbolEndAddress = SymbolStartAddress + SymbolSize;

    if (SymbolEndAddress.isValid()
        and SymbolStartAddress.addressGreaterThanOrEqual(StructStartAddress)
        and SymbolEndAddress.addressLowerThanOrEqual(StructEndAddress)) {
      auto Offset = SymbolStartAddress - StructStartAddress;
      revng_assert(Offset.has_value());

      // Discard any symbols that would overlap an already existing one.
      if (checkForOverlap(Struct, *Offset, SymbolSize)) {
        It = std::prev(DataSymbols.erase(It));
        continue;
      }

      model::StructField &Field = Struct.addField(*Offset, {});
      Field.Offset() = *Offset;
      Field.Name() = SymbolName.str();
      if (SymbolSize == 1 || SymbolSize == 2 || SymbolSize == 4
          || SymbolSize == 8) {
        Field.Type() = model::PrimitiveType::makeGeneric(SymbolSize);
      } else {
        // If the symbol has a non-standard size, make it an empty struct with
        // the same size instead.
        Field.Type() = Binary.makeStructDefinition(SymbolSize).second;
      }
    }
  }
}

struct Section {
  MetaAddress StartAddress;
  uint64_t Size;
  bool CanContainCode = false;
  std::string Name;
};

inline model::UpcastableType
populateSegmentTypeStruct(model::Binary &Binary,
                          model::Segment &Segment,
                          llvm::SmallVector<DataSymbol, 32> DataSymbols,
                          llvm::ArrayRef<Section> Sections,
                          bool SegmentIsExecutable) {
  using namespace llvm;
  using namespace model;

  // Create a struct for the segment
  revng_assert(Segment.VirtualSize() > 0);
  auto &&[SegmentStruct,
          SegmentType] = Binary.makeStructDefinition(Segment.VirtualSize());
  SegmentStruct.CanContainCode() = SegmentIsExecutable;

  for (const auto &Section : Sections) {
    if (not Segment.contains(Section.StartAddress, Section.Size))
      continue;

    auto Offset = Section.StartAddress - Segment.StartAddress();
    revng_assert(Offset.has_value());

    if (checkForOverlap(SegmentStruct, *Offset, Section.Size))
      continue;

    // Create a struct for each section
    auto &&[SectionStruct, Type] = Binary.makeStructDefinition(Section.Size);
    SectionStruct.CanContainCode() = (SegmentIsExecutable
                                      and Section.CanContainCode);

    // Import (and consume) symbols that fall within such section
    importSymbolsInto(Binary, DataSymbols, SectionStruct, Section.StartAddress);

    // Insert the field the segment struct
    auto &SectionField = SegmentStruct.addField(*Offset, std::move(Type));

    // TODO: This is the only place where we automatically change names coming
    //       from the binary (aside from the deduplication, but that's
    //       a separate issue). Are we happy with this?

    llvm::StringRef Name = Section.Name;
    if (Name.starts_with("."))
      Name = Name.drop_front();

    constexpr auto ReplaceDots = std::views::transform([](char Character) {
      return Character != '.' ? Character : '_';
    });
    SectionField.Name() = Name | ReplaceDots | revng::to<std::string>();
  }

  // Pour the remaining symbols into the segment struct
  importSymbolsInto(Binary, DataSymbols, SegmentStruct, Segment.StartAddress());

  revng_assert(SegmentStruct.verify(true));
  return std::move(SegmentType);
}