//===--- DWARFVisitor.cpp ---------------------------------------*- 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
//
//===----------------------------------------------------------------------===//
//
//===----------------------------------------------------------------------===//

#include "DWARFVisitor.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/ObjectYAML/DWARFYAML.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/Error.h"

using namespace llvm;

template <typename T>
void DWARFYAML::VisitorImpl<T>::onVariableSizeValue(uint64_t U, unsigned Size) {
  switch (Size) {
  case 8:
    onValue((uint64_t)U);
    break;
  case 4:
    onValue((uint32_t)U);
    break;
  case 2:
    onValue((uint16_t)U);
    break;
  case 1:
    onValue((uint8_t)U);
    break;
  default:
    llvm_unreachable("Invalid integer write size.");
  }
}

static unsigned getOffsetSize(const DWARFYAML::Unit &Unit) {
  return Unit.Format == dwarf::DWARF64 ? 8 : 4;
}

static unsigned getRefSize(const DWARFYAML::Unit &Unit) {
  if (Unit.Version == 2)
    return Unit.AddrSize;
  return getOffsetSize(Unit);
}

template <typename T> Error DWARFYAML::VisitorImpl<T>::traverseDebugInfo() {
  for (auto &Unit : DebugInfo.CompileUnits) {
    onStartCompileUnit(Unit);
    if (Unit.Entries.empty())
      continue;

    for (auto &Entry : Unit.Entries) {
      onStartDIE(Unit, Entry);
      uint32_t AbbrCode = Entry.AbbrCode;
      if (AbbrCode == 0 || Entry.Values.empty())
        continue;

      if (AbbrCode > DebugInfo.AbbrevDecls.size())
        return createStringError(
            errc::invalid_argument,
            "abbrev code must be less than or equal to the number of "
            "entries in abbreviation table");
      const DWARFYAML::Abbrev &Abbrev = DebugInfo.AbbrevDecls[AbbrCode - 1];
      auto FormVal = Entry.Values.begin();
      auto AbbrForm = Abbrev.Attributes.begin();
      for (;
           FormVal != Entry.Values.end() && AbbrForm != Abbrev.Attributes.end();
           ++FormVal, ++AbbrForm) {
        onForm(*AbbrForm, *FormVal);
        dwarf::Form Form = AbbrForm->Form;
        bool Indirect;
        do {
          Indirect = false;
          switch (Form) {
          case dwarf::DW_FORM_addr:
            onVariableSizeValue(FormVal->Value, Unit.AddrSize);
            break;
          case dwarf::DW_FORM_ref_addr:
            onVariableSizeValue(FormVal->Value, getRefSize(Unit));
            break;
          case dwarf::DW_FORM_exprloc:
          case dwarf::DW_FORM_block:
            onValue((uint64_t)FormVal->BlockData.size(), true);
            onValue(
                MemoryBufferRef(StringRef((const char *)&FormVal->BlockData[0],
                                          FormVal->BlockData.size()),
                                ""));
            break;
          case dwarf::DW_FORM_block1: {
            auto writeSize = FormVal->BlockData.size();
            onValue((uint8_t)writeSize);
            onValue(
                MemoryBufferRef(StringRef((const char *)&FormVal->BlockData[0],
                                          FormVal->BlockData.size()),
                                ""));
            break;
          }
          case dwarf::DW_FORM_block2: {
            auto writeSize = FormVal->BlockData.size();
            onValue((uint16_t)writeSize);
            onValue(
                MemoryBufferRef(StringRef((const char *)&FormVal->BlockData[0],
                                          FormVal->BlockData.size()),
                                ""));
            break;
          }
          case dwarf::DW_FORM_block4: {
            auto writeSize = FormVal->BlockData.size();
            onValue((uint32_t)writeSize);
            onValue(
                MemoryBufferRef(StringRef((const char *)&FormVal->BlockData[0],
                                          FormVal->BlockData.size()),
                                ""));
            break;
          }
          case dwarf::DW_FORM_strx:
          case dwarf::DW_FORM_addrx:
          case dwarf::DW_FORM_rnglistx:
          case dwarf::DW_FORM_loclistx:
            onValue((uint64_t)FormVal->Value, /*LEB=*/true);
            break;
          case dwarf::DW_FORM_data1:
          case dwarf::DW_FORM_ref1:
          case dwarf::DW_FORM_flag:
          case dwarf::DW_FORM_strx1:
          case dwarf::DW_FORM_addrx1:
            onValue((uint8_t)FormVal->Value);
            break;
          case dwarf::DW_FORM_data2:
          case dwarf::DW_FORM_ref2:
          case dwarf::DW_FORM_strx2:
          case dwarf::DW_FORM_addrx2:
            onValue((uint16_t)FormVal->Value);
            break;
          case dwarf::DW_FORM_data4:
          case dwarf::DW_FORM_ref4:
          case dwarf::DW_FORM_ref_sup4:
          case dwarf::DW_FORM_strx4:
          case dwarf::DW_FORM_addrx4:
            onValue((uint32_t)FormVal->Value);
            break;
          case dwarf::DW_FORM_data8:
          case dwarf::DW_FORM_ref8:
          case dwarf::DW_FORM_ref_sup8:
            onValue((uint64_t)FormVal->Value);
            break;
          case dwarf::DW_FORM_sdata:
            onValue((int64_t)FormVal->Value, true);
            break;
          case dwarf::DW_FORM_udata:
          case dwarf::DW_FORM_ref_udata:
            onValue((uint64_t)FormVal->Value, true);
            break;
          case dwarf::DW_FORM_string:
            onValue(FormVal->CStr);
            break;
          case dwarf::DW_FORM_indirect:
            onValue((uint64_t)FormVal->Value, true);
            Indirect = true;
            Form = static_cast<dwarf::Form>((uint64_t)FormVal->Value);
            ++FormVal;
            break;
          case dwarf::DW_FORM_strp:
          case dwarf::DW_FORM_sec_offset:
          case dwarf::DW_FORM_GNU_ref_alt:
          case dwarf::DW_FORM_GNU_strp_alt:
          case dwarf::DW_FORM_line_strp:
          case dwarf::DW_FORM_strp_sup:
            onVariableSizeValue(FormVal->Value, getOffsetSize(Unit));
            break;
          case dwarf::DW_FORM_ref_sig8:
            onValue((uint64_t)FormVal->Value);
            break;
          case dwarf::DW_FORM_GNU_addr_index:
          case dwarf::DW_FORM_GNU_str_index:
            onValue((uint64_t)FormVal->Value, true);
            break;
          default:
            break;
          }
        } while (Indirect);
      }
      onEndDIE(Unit, Entry);
    }
    onEndCompileUnit(Unit);
  }

  return Error::success();
}

// Explicitly instantiate the two template expansions.
template class DWARFYAML::VisitorImpl<DWARFYAML::Data>;
template class DWARFYAML::VisitorImpl<const DWARFYAML::Data>;