1//===- THMToTHMStub.cpp ---------------------------------------------------===//
2//
3//                     The MCLinker Project
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "THMToTHMStub.h"
11#include "ARMLDBackend.h"
12
13#include <llvm/Support/ELF.h>
14#include <mcld/LD/ResolveInfo.h>
15#include <mcld/LD/LDSymbol.h>
16#include <mcld/Fragment/Relocation.h>
17
18using namespace mcld;
19
20//===----------------------------------------------------------------------===//
21// THMToTHMStub
22//===----------------------------------------------------------------------===//
23const uint32_t THMToTHMStub::PIC_TEMPLATE[] = {
24  0x46c04778, // bx    pc ... nop
25  0xe59fc004, // ldr   r12, [pc, #4]
26  0xe08fc00c, // add   ip, pc, ip
27  0xe12fff1c, // bx    ip
28  0x0         // dcd   R_ARM_REL32(X)
29};
30
31const uint32_t THMToTHMStub::TEMPLATE[] = {
32  0x46c04778, // bx    pc ... nop
33  0xe59fc000, // ldr   ip, [pc, #0]
34  0xe12fff1c, // bx    ip
35  0x0         // dcd   R_ARM_ABS32(X)
36};
37
38THMToTHMStub::THMToTHMStub(bool pIsOutputPIC)
39 : Stub(), m_Name("T2T_prototype"), m_pData(NULL), m_Size(0x0)
40{
41  if (pIsOutputPIC) {
42    m_pData = PIC_TEMPLATE;
43    m_Size = sizeof(PIC_TEMPLATE);
44    addFixup(16u, 0x0, llvm::ELF::R_ARM_REL32);
45  }
46  else {
47    m_pData = TEMPLATE;
48    m_Size = sizeof(TEMPLATE);
49    addFixup(12u, 0x0, llvm::ELF::R_ARM_ABS32);
50  }
51}
52
53/// for doClone
54THMToTHMStub::THMToTHMStub(const uint32_t* pData,
55                           size_t pSize,
56                           const_fixup_iterator pBegin,
57                           const_fixup_iterator pEnd)
58 : Stub(), m_Name("T2T_veneer"), m_pData(pData), m_Size(pSize)
59{
60  for (const_fixup_iterator it = pBegin, ie = pEnd; it != ie; ++it)
61    addFixup(**it);
62}
63
64THMToTHMStub::~THMToTHMStub()
65{
66}
67
68bool THMToTHMStub::isMyDuty(const class Relocation& pReloc,
69                            uint64_t pSource,
70                            uint64_t pTargetSymValue) const
71{
72  bool result = false;
73  // Check if the branch target is THUMB
74  if ((pTargetSymValue & 0x1) != 0x0) {
75    switch (pReloc.type()) {
76      case llvm::ELF::R_ARM_THM_CALL:
77      case llvm::ELF::R_ARM_THM_JUMP24: {
78        // Check if the branch target is too far
79        uint64_t dest = pTargetSymValue + pReloc.addend() + 4u;
80        int64_t branch_offset = static_cast<int64_t>(dest) - pSource;
81        if ((branch_offset > ARMGNULDBackend::THM_MAX_FWD_BRANCH_OFFSET) ||
82            (branch_offset < ARMGNULDBackend::THM_MAX_BWD_BRANCH_OFFSET))
83          result =  true;
84        break;
85      }
86      default:
87        break;
88    }
89  }
90  return result;
91}
92
93const std::string& THMToTHMStub::name() const
94{
95  return m_Name;
96}
97
98const uint8_t* THMToTHMStub::getContent() const
99{
100  return reinterpret_cast<const uint8_t*>(m_pData);
101}
102
103size_t THMToTHMStub::size() const
104{
105  return m_Size;
106}
107
108size_t THMToTHMStub::alignment() const
109{
110  return 4u;
111}
112
113uint64_t THMToTHMStub::initSymValue() const
114{
115  return 0x1;
116}
117
118Stub* THMToTHMStub::doClone()
119{
120  return new THMToTHMStub(m_pData, m_Size, fixup_begin(), fixup_end());
121}
122
123