//===- THMToTHMStub.cpp ---------------------------------------------------===//
//
//                     The MCLinker Project
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "THMToTHMStub.h"
#include "ARMLDBackend.h"

#include <llvm/Support/ELF.h>
#include <mcld/LD/ResolveInfo.h>
#include <mcld/LD/LDSymbol.h>
#include <mcld/Fragment/Relocation.h>

using namespace mcld;

//===----------------------------------------------------------------------===//
// THMToTHMStub
//===----------------------------------------------------------------------===//
const uint32_t THMToTHMStub::PIC_TEMPLATE[] = {
  0x46c04778, // bx    pc ... nop
  0xe59fc004, // ldr   r12, [pc, #4]
  0xe08fc00c, // add   ip, pc, ip
  0xe12fff1c, // bx    ip
  0x0         // dcd   R_ARM_REL32(X)
};

const uint32_t THMToTHMStub::TEMPLATE[] = {
  0x46c04778, // bx    pc ... nop
  0xe59fc000, // ldr   ip, [pc, #0]
  0xe12fff1c, // bx    ip
  0x0         // dcd   R_ARM_ABS32(X)
};

THMToTHMStub::THMToTHMStub(bool pIsOutputPIC, bool pUsingThumb2)
 : m_pData(NULL),
   m_Name("T2T_prototype"),
   m_Size(0x0),
   m_bUsingThumb2(pUsingThumb2)
{
  if (pIsOutputPIC) {
    m_pData = PIC_TEMPLATE;
    m_Size = sizeof(PIC_TEMPLATE);
    addFixup(16u, 0x0, llvm::ELF::R_ARM_REL32);
  } else {
    m_pData = TEMPLATE;
    m_Size = sizeof(TEMPLATE);
    addFixup(12u, 0x0, llvm::ELF::R_ARM_ABS32);
  }
}

/// for doClone
THMToTHMStub::THMToTHMStub(const uint32_t* pData,
                           size_t pSize,
                           const_fixup_iterator pBegin,
                           const_fixup_iterator pEnd,
                           bool pUsingThumb2)
 : m_pData(pData),
   m_Name("T2T_veneer"),
   m_Size(pSize),
   m_bUsingThumb2(pUsingThumb2)
{
  for (const_fixup_iterator it = pBegin, ie = pEnd; it != ie; ++it)
    addFixup(**it);
}

THMToTHMStub::~THMToTHMStub()
{
}

bool THMToTHMStub::isMyDuty(const class Relocation& pReloc,
                            uint64_t pSource,
                            uint64_t pTargetSymValue) const
{
  bool result = false;
  // Check if the branch target is THUMB
  if ((pTargetSymValue & 0x1) != 0x0) {
    switch (pReloc.type()) {
      case llvm::ELF::R_ARM_THM_CALL:
      case llvm::ELF::R_ARM_THM_JUMP24: {
        // Check if the branch target is too far
        uint64_t dest = pTargetSymValue + pReloc.addend() + 4u;
        int64_t branch_offset = static_cast<int64_t>(dest) - pSource;
        if (m_bUsingThumb2) {
           if ((branch_offset > ARMGNULDBackend::THM2_MAX_FWD_BRANCH_OFFSET) ||
               (branch_offset < ARMGNULDBackend::THM2_MAX_BWD_BRANCH_OFFSET)) {
             result = true;
             break;
           }
        } else {
          if ((branch_offset > ARMGNULDBackend::THM_MAX_FWD_BRANCH_OFFSET) ||
              (branch_offset < ARMGNULDBackend::THM_MAX_BWD_BRANCH_OFFSET)) {
            result = true;
            break;
          }
        }
        break;
      }
      default:
        break;
    }
  }
  return result;
}

const std::string& THMToTHMStub::name() const
{
  return m_Name;
}

const uint8_t* THMToTHMStub::getContent() const
{
  return reinterpret_cast<const uint8_t*>(m_pData);
}

size_t THMToTHMStub::size() const
{
  return m_Size;
}

size_t THMToTHMStub::alignment() const
{
  return 4u;
}

uint64_t THMToTHMStub::initSymValue() const
{
  return 0x1;
}

Stub* THMToTHMStub::doClone()
{
  return new THMToTHMStub(m_pData,
                          m_Size,
                          fixup_begin(),
                          fixup_end(),
                          m_bUsingThumb2);
}