//===- FunctionInfo.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/DebugInfo/GSYM/FunctionInfo.h"
#include "llvm/DebugInfo/GSYM/FileWriter.h"
#include "llvm/DebugInfo/GSYM/LineTable.h"
#include "llvm/DebugInfo/GSYM/InlineInfo.h"
#include "llvm/Support/DataExtractor.h"

using namespace llvm;
using namespace gsym;

/// FunctionInfo information type that is used to encode the optional data
/// that is associated with a FunctionInfo object.
enum InfoType : uint32_t {
  EndOfList = 0u,
  LineTableInfo = 1u,
  InlineInfo = 2u
};

raw_ostream &llvm::gsym::operator<<(raw_ostream &OS, const FunctionInfo &FI) {
  OS << '[' << HEX64(FI.Range.Start) << '-' << HEX64(FI.Range.End) << "): "
     << "Name=" << HEX32(FI.Name) << '\n' << FI.OptLineTable << FI.Inline;
  return OS;
}

llvm::Expected<FunctionInfo> FunctionInfo::decode(DataExtractor &Data,
                                                  uint64_t BaseAddr) {
  FunctionInfo FI;
  FI.Range.Start = BaseAddr;
  uint64_t Offset = 0;
  if (!Data.isValidOffsetForDataOfSize(Offset, 4))
    return createStringError(std::errc::io_error,
        "0x%8.8" PRIx64 ": missing FunctionInfo Size", Offset);
  FI.Range.End = FI.Range.Start + Data.getU32(&Offset);
  if (!Data.isValidOffsetForDataOfSize(Offset, 4))
    return createStringError(std::errc::io_error,
        "0x%8.8" PRIx64 ": missing FunctionInfo Name", Offset);
  FI.Name = Data.getU32(&Offset);
  if (FI.Name == 0)
    return createStringError(std::errc::io_error,
        "0x%8.8" PRIx64 ": invalid FunctionInfo Name value 0x%8.8x",
        Offset - 4, FI.Name);
  bool Done = false;
  while (!Done) {
    if (!Data.isValidOffsetForDataOfSize(Offset, 4))
      return createStringError(std::errc::io_error,
          "0x%8.8" PRIx64 ": missing FunctionInfo InfoType value", Offset);
    const uint32_t IT = Data.getU32(&Offset);
    if (!Data.isValidOffsetForDataOfSize(Offset, 4))
      return createStringError(std::errc::io_error,
          "0x%8.8" PRIx64 ": missing FunctionInfo InfoType length", Offset);
    const uint32_t InfoLength = Data.getU32(&Offset);
    if (!Data.isValidOffsetForDataOfSize(Offset, InfoLength))
      return createStringError(std::errc::io_error,
          "0x%8.8" PRIx64 ": missing FunctionInfo data for InfoType %u",
          Offset, IT);
    DataExtractor InfoData(Data.getData().substr(Offset, InfoLength),
                           Data.isLittleEndian(),
                           Data.getAddressSize());
    switch (IT) {
      case InfoType::EndOfList:
        Done = true;
        break;

      case InfoType::LineTableInfo:
        if (Expected<LineTable> LT = LineTable::decode(InfoData, BaseAddr))
          FI.OptLineTable = std::move(LT.get());
        else
          return LT.takeError();
        break;

      case InfoType::InlineInfo:
        if (Expected<InlineInfo> II = InlineInfo::decode(InfoData, BaseAddr))
          FI.Inline = std::move(II.get());
        else
          return II.takeError();
        break;

      default:
        return createStringError(std::errc::io_error,
                                 "0x%8.8" PRIx64 ": unsupported InfoType %u",
                                 Offset-8, IT);
    }
    Offset += InfoLength;
  }
  return std::move(FI);
}

llvm::Expected<uint64_t> FunctionInfo::encode(FileWriter &O) const {
  if (!isValid())
    return createStringError(std::errc::invalid_argument,
        "attempted to encode invalid FunctionInfo object");
  // Align FunctionInfo data to a 4 byte alignment.
  O.alignTo(4);
  const uint64_t FuncInfoOffset = O.tell();
  // Write the size in bytes of this function as a uint32_t. This can be zero
  // if we just have a symbol from a symbol table and that symbol has no size.
  O.writeU32(size());
  // Write the name of this function as a uint32_t string table offset.
  O.writeU32(Name);

  if (OptLineTable.hasValue()) {
    O.writeU32(InfoType::LineTableInfo);
    // Write a uint32_t length as zero for now, we will fix this up after
    // writing the LineTable out with the number of bytes that were written.
    O.writeU32(0);
    const auto StartOffset = O.tell();
    llvm::Error err = OptLineTable->encode(O, Range.Start);
    if (err)
      return std::move(err);
    const off_t Length = O.tell() - StartOffset;
    if (Length > UINT32_MAX)
        return createStringError(std::errc::invalid_argument,
            "LineTable length is greater than UINT32_MAX");
    // Fixup the size of the LineTable data with the correct size.
    O.fixup32(static_cast<uint32_t>(Length), StartOffset - 4);
  }

  // Write out the inline function info if we have any and if it is valid.
  if (Inline.hasValue()) {
    O.writeU32(InfoType::InlineInfo);
    // Write a uint32_t length as zero for now, we will fix this up after
    // writing the LineTable out with the number of bytes that were written.
    O.writeU32(0);
    const auto StartOffset = O.tell();
    llvm::Error err = Inline->encode(O, Range.Start);
    if (err)
      return std::move(err);
    const off_t Length = O.tell() - StartOffset;
    if (Length > UINT32_MAX)
        return createStringError(std::errc::invalid_argument,
            "InlineInfo length is greater than UINT32_MAX");
    // Fixup the size of the InlineInfo data with the correct size.
    O.fixup32(static_cast<uint32_t>(Length), StartOffset - 4);
  }

  // Terminate the data chunks with and end of list with zero size
  O.writeU32(InfoType::EndOfList);
  O.writeU32(0);
  return FuncInfoOffset;
}