llvm-mirror/lib/InterfaceStub/TBEHandler.cpp

//===- TBEHandler.cpp -----------------------------------------------------===//
//
// 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
//
//===-----------------------------------------------------------------------===/

#include "llvm/InterfaceStub/TBEHandler.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/Triple.h"
#include "llvm/InterfaceStub/ELFStub.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/LineIterator.h"
#include "llvm/Support/YAMLTraits.h"

using namespace llvm;
using namespace llvm::elfabi;

LLVM_YAML_IS_SEQUENCE_VECTOR(ELFSymbol)

namespace llvm {
namespace yaml {

/// YAML traits for ELFSymbolType.
template <> struct ScalarEnumerationTraits<ELFSymbolType> {
  static void enumeration(IO &IO, ELFSymbolType &SymbolType) {
    IO.enumCase(SymbolType, "NoType", ELFSymbolType::NoType);
    IO.enumCase(SymbolType, "Func", ELFSymbolType::Func);
    IO.enumCase(SymbolType, "Object", ELFSymbolType::Object);
    IO.enumCase(SymbolType, "TLS", ELFSymbolType::TLS);
    IO.enumCase(SymbolType, "Unknown", ELFSymbolType::Unknown);
    // Treat other symbol types as noise, and map to Unknown.
    if (!IO.outputting() && IO.matchEnumFallback())
      SymbolType = ELFSymbolType::Unknown;
  }
};

template <> struct ScalarTraits<ELFEndiannessType> {
  static void output(const ELFEndiannessType &Value, void *,
                     llvm::raw_ostream &Out) {
    switch (Value) {
    case ELFEndiannessType::Big:
      Out << "big";
      break;
    case ELFEndiannessType::Little:
      Out << "little";
      break;
    default:
      llvm_unreachable("Unsupported endianness");
    }
  }

  static StringRef input(StringRef Scalar, void *, ELFEndiannessType &Value) {
    Value = StringSwitch<ELFEndiannessType>(Scalar)
                .Case("big", ELFEndiannessType::Big)
                .Case("little", ELFEndiannessType::Little)
                .Default(ELFEndiannessType::Unknown);
    if (Value == ELFEndiannessType::Unknown) {
      return "Unsupported endianness";
    }
    return StringRef();
  }

  static QuotingType mustQuote(StringRef) { return QuotingType::None; }
};

template <> struct ScalarTraits<ELFBitWidthType> {
  static void output(const ELFBitWidthType &Value, void *,
                     llvm::raw_ostream &Out) {
    switch (Value) {
    case ELFBitWidthType::ELF32:
      Out << "32";
      break;
    case ELFBitWidthType::ELF64:
      Out << "64";
      break;
    default:
      llvm_unreachable("Unsupported bit width");
    }
  }

  static StringRef input(StringRef Scalar, void *, ELFBitWidthType &Value) {
    Value = StringSwitch<ELFBitWidthType>(Scalar)
                .Case("32", ELFBitWidthType::ELF32)
                .Case("64", ELFBitWidthType::ELF64)
                .Default(ELFBitWidthType::Unknown);
    if (Value == ELFBitWidthType::Unknown) {
      return "Unsupported bit width";
    }
    return StringRef();
  }

  static QuotingType mustQuote(StringRef) { return QuotingType::None; }
};

template <> struct MappingTraits<IFSTarget> {
  static void mapping(IO &IO, IFSTarget &Target) {
    IO.mapOptional("ObjectFormat", Target.ObjectFormat);
    IO.mapOptional("Arch", Target.ArchString);
    IO.mapOptional("Endianness", Target.Endianness);
    IO.mapOptional("BitWidth", Target.BitWidth);
  }

  // Compacts symbol information into a single line.
  static const bool flow = true; // NOLINT(readability-identifier-naming)
};

/// YAML traits for ELFSymbol.
template <> struct MappingTraits<ELFSymbol> {
  static void mapping(IO &IO, ELFSymbol &Symbol) {
    IO.mapRequired("Name", Symbol.Name);
    IO.mapRequired("Type", Symbol.Type);
    // The need for symbol size depends on the symbol type.
    if (Symbol.Type == ELFSymbolType::NoType) {
      IO.mapOptional("Size", Symbol.Size, (uint64_t)0);
    } else if (Symbol.Type == ELFSymbolType::Func) {
      Symbol.Size = 0;
    } else {
      IO.mapRequired("Size", Symbol.Size);
    }
    IO.mapOptional("Undefined", Symbol.Undefined, false);
    IO.mapOptional("Weak", Symbol.Weak, false);
    IO.mapOptional("Warning", Symbol.Warning);
  }

  // Compacts symbol information into a single line.
  static const bool flow = true; // NOLINT(readability-identifier-naming)
};

/// YAML traits for ELFStub objects.
template <> struct MappingTraits<ELFStub> {
  static void mapping(IO &IO, ELFStub &Stub) {
    if (!IO.mapTag("!ifs-v1", true))
      IO.setError("Not a .tbe YAML file.");
    IO.mapRequired("TbeVersion", Stub.TbeVersion);
    IO.mapOptional("SoName", Stub.SoName);
    IO.mapOptional("Target", Stub.Target);
    IO.mapOptional("NeededLibs", Stub.NeededLibs);
    IO.mapRequired("Symbols", Stub.Symbols);
  }
};

/// YAML traits for ELFStubTriple objects.
template <> struct MappingTraits<ELFStubTriple> {
  static void mapping(IO &IO, ELFStubTriple &Stub) {
    if (!IO.mapTag("!ifs-v1", true))
      IO.setError("Not a .tbe YAML file.");
    IO.mapRequired("TbeVersion", Stub.TbeVersion);
    IO.mapOptional("SoName", Stub.SoName);
    IO.mapOptional("Target", Stub.Target.Triple);
    IO.mapOptional("NeededLibs", Stub.NeededLibs);
    IO.mapRequired("Symbols", Stub.Symbols);
  }
};
} // end namespace yaml
} // end namespace llvm

/// Attempt to determine if a Text stub uses target triple.
bool usesTriple(StringRef Buf) {
  for (line_iterator I(MemoryBufferRef(Buf, "ELFStub")); !I.is_at_eof(); ++I) {
    StringRef Line = (*I).trim();
    if (Line.startswith("Target:")) {
      if (Line == "Target:" || (Line.find("{") != Line.npos)) {
        return false;
      }
    }
  }
  return true;
}

Expected<std::unique_ptr<ELFStub>> elfabi::readTBEFromBuffer(StringRef Buf) {
  yaml::Input YamlIn(Buf);
  std::unique_ptr<ELFStubTriple> Stub(new ELFStubTriple());
  if (usesTriple(Buf)) {
    YamlIn >> *Stub;
  } else {
    YamlIn >> *static_cast<ELFStub *>(Stub.get());
  }
  if (std::error_code Err = YamlIn.error()) {
    return createStringError(Err, "YAML failed reading as TBE");
  }

  if (Stub->TbeVersion > elfabi::TBEVersionCurrent)
    return make_error<StringError>(
        "TBE version " + Stub->TbeVersion.getAsString() + " is unsupported.",
        std::make_error_code(std::errc::invalid_argument));
  if (Stub->Target.ArchString) {
    Stub->Target.Arch =
        ELF::convertArchNameToEMachine(Stub->Target.ArchString.getValue());
  }
  return std::move(Stub);
}

Error elfabi::writeTBEToOutputStream(raw_ostream &OS, const ELFStub &Stub) {
  yaml::Output YamlOut(OS, NULL, /*WrapColumn =*/0);
  std::unique_ptr<ELFStubTriple> CopyStub(new ELFStubTriple(Stub));
  if (Stub.Target.Arch) {
    CopyStub->Target.ArchString = std::string(
        ELF::convertEMachineToArchName(Stub.Target.Arch.getValue()));
  }
  IFSTarget Target = Stub.Target;

  if (CopyStub->Target.Triple ||
      (!CopyStub->Target.ArchString && !CopyStub->Target.Endianness &&
       !CopyStub->Target.BitWidth))
    YamlOut << *CopyStub;
  else
    YamlOut << *static_cast<ELFStub *>(CopyStub.get());
  return Error::success();
}

Error elfabi::overrideTBETarget(ELFStub &Stub, Optional<ELFArch> OverrideArch,
                                Optional<ELFEndiannessType> OverrideEndianness,
                                Optional<ELFBitWidthType> OverrideBitWidth,
                                Optional<std::string> OverrideTriple) {
  std::error_code OverrideEC(1, std::generic_category());
  if (OverrideArch) {
    if (Stub.Target.Arch &&
        Stub.Target.Arch.getValue() != OverrideArch.getValue()) {
      return make_error<StringError>(
          "Supplied Arch conflicts with the text stub", OverrideEC);
    }
    Stub.Target.Arch = OverrideArch.getValue();
  }
  if (OverrideEndianness) {
    if (Stub.Target.Endianness &&
        Stub.Target.Endianness.getValue() != OverrideEndianness.getValue()) {
      return make_error<StringError>(
          "Supplied Endianness conflicts with the text stub", OverrideEC);
    }
    Stub.Target.Endianness = OverrideEndianness.getValue();
  }
  if (OverrideBitWidth) {
    if (Stub.Target.BitWidth &&
        Stub.Target.BitWidth.getValue() != OverrideBitWidth.getValue()) {
      return make_error<StringError>(
          "Supplied BitWidth conflicts with the text stub", OverrideEC);
    }
    Stub.Target.BitWidth = OverrideBitWidth.getValue();
  }
  if (OverrideTriple) {
    if (Stub.Target.Triple &&
        Stub.Target.Triple.getValue() != OverrideTriple.getValue()) {
      return make_error<StringError>(
          "Supplied Triple conflicts with the text stub", OverrideEC);
    }
    Stub.Target.Triple = OverrideTriple.getValue();
  }
  return Error::success();
}

Error elfabi::validateTBETarget(ELFStub &Stub, bool ParseTriple) {
  std::error_code ValidationEC(1, std::generic_category());
  if (Stub.Target.Triple) {
    if (Stub.Target.Arch || Stub.Target.BitWidth || Stub.Target.Endianness ||
        Stub.Target.ObjectFormat) {
      return make_error<StringError>(
          "Target triple cannot be used simultaneously with ELF target format",
          ValidationEC);
    }
    if (ParseTriple) {
      IFSTarget TargetFromTriple = parseTriple(Stub.Target.Triple.getValue());
      Stub.Target.Arch = TargetFromTriple.Arch;
      Stub.Target.BitWidth = TargetFromTriple.BitWidth;
      Stub.Target.Endianness = TargetFromTriple.Endianness;
    }
    return Error::success();
  }
  if (!Stub.Target.Arch || !Stub.Target.BitWidth || !Stub.Target.Endianness) {
    // TODO: unify the error message.
    if (!Stub.Target.Arch) {
      return make_error<StringError>("Arch is not defined in the text stub",
                                     ValidationEC);
    }
    if (!Stub.Target.BitWidth) {
      return make_error<StringError>("BitWidth is not defined in the text stub",
                                     ValidationEC);
    }
    if (!Stub.Target.Endianness) {
      return make_error<StringError>(
          "Endianness is not defined in the text stub", ValidationEC);
    }
  }
  return Error::success();
}

IFSTarget elfabi::parseTriple(StringRef TripleStr) {
  Triple IFSTriple(TripleStr);
  IFSTarget RetTarget;
  // TODO: Implement a Triple Arch enum to e_machine map.
  switch (IFSTriple.getArch()) {
  case Triple::ArchType::aarch64:
    RetTarget.Arch = (ELFArch)ELF::EM_AARCH64;
    break;
  case Triple::ArchType::x86_64:
    RetTarget.Arch = (ELFArch)ELF::EM_X86_64;
    break;
  default:
    RetTarget.Arch = (ELFArch)ELF::EM_NONE;
  }
  RetTarget.Endianness = IFSTriple.isLittleEndian() ? ELFEndiannessType::Little
                                                    : ELFEndiannessType::Big;
  RetTarget.BitWidth =
      IFSTriple.isArch64Bit() ? ELFBitWidthType::ELF64 : ELFBitWidthType::ELF32;
  return RetTarget;
}

void elfabi::stripTBETarget(ELFStub &Stub, bool StripTriple, bool StripArch,
                            bool StripEndianness, bool StripBitWidth) {
  if (StripTriple || StripArch) {
    Stub.Target.Arch.reset();
    Stub.Target.ArchString.reset();
  }
  if (StripTriple || StripEndianness) {
    Stub.Target.Endianness.reset();
  }
  if (StripTriple || StripBitWidth) {
    Stub.Target.BitWidth.reset();
  }
  if (StripTriple) {
    Stub.Target.Triple.reset();
  }
  if (!Stub.Target.Arch && !Stub.Target.BitWidth && !Stub.Target.Endianness) {
    Stub.Target.ObjectFormat.reset();
  }
}