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, bool pUsingThumb2)
39 : m_pData(NULL),
40   m_Name("T2T_prototype"),
41   m_Size(0x0),
42   m_bUsingThumb2(pUsingThumb2)
43{
44  if (pIsOutputPIC) {
45    m_pData = PIC_TEMPLATE;
46    m_Size = sizeof(PIC_TEMPLATE);
47    addFixup(16u, 0x0, llvm::ELF::R_ARM_REL32);
48  } else {
49    m_pData = TEMPLATE;
50    m_Size = sizeof(TEMPLATE);
51    addFixup(12u, 0x0, llvm::ELF::R_ARM_ABS32);
52  }
53}
54
55/// for doClone
56THMToTHMStub::THMToTHMStub(const uint32_t* pData,
57                           size_t pSize,
58                           const_fixup_iterator pBegin,
59                           const_fixup_iterator pEnd,
60                           bool pUsingThumb2)
61 : m_pData(pData),
62   m_Name("T2T_veneer"),
63   m_Size(pSize),
64   m_bUsingThumb2(pUsingThumb2)
65{
66  for (const_fixup_iterator it = pBegin, ie = pEnd; it != ie; ++it)
67    addFixup(**it);
68}
69
70THMToTHMStub::~THMToTHMStub()
71{
72}
73
74bool THMToTHMStub::isMyDuty(const class Relocation& pReloc,
75                            uint64_t pSource,
76                            uint64_t pTargetSymValue) const
77{
78  bool result = false;
79  // Check if the branch target is THUMB
80  if ((pTargetSymValue & 0x1) != 0x0) {
81    switch (pReloc.type()) {
82      case llvm::ELF::R_ARM_THM_CALL:
83      case llvm::ELF::R_ARM_THM_JUMP24: {
84        // Check if the branch target is too far
85        uint64_t dest = pTargetSymValue + pReloc.addend() + 4u;
86        int64_t branch_offset = static_cast<int64_t>(dest) - pSource;
87        if (m_bUsingThumb2) {
88           if ((branch_offset > ARMGNULDBackend::THM2_MAX_FWD_BRANCH_OFFSET) ||
89               (branch_offset < ARMGNULDBackend::THM2_MAX_BWD_BRANCH_OFFSET)) {
90             result = true;
91             break;
92           }
93        } else {
94          if ((branch_offset > ARMGNULDBackend::THM_MAX_FWD_BRANCH_OFFSET) ||
95              (branch_offset < ARMGNULDBackend::THM_MAX_BWD_BRANCH_OFFSET)) {
96            result = true;
97            break;
98          }
99        }
100        break;
101      }
102      default:
103        break;
104    }
105  }
106  return result;
107}
108
109const std::string& THMToTHMStub::name() const
110{
111  return m_Name;
112}
113
114const uint8_t* THMToTHMStub::getContent() const
115{
116  return reinterpret_cast<const uint8_t*>(m_pData);
117}
118
119size_t THMToTHMStub::size() const
120{
121  return m_Size;
122}
123
124size_t THMToTHMStub::alignment() const
125{
126  return 4u;
127}
128
129uint64_t THMToTHMStub::initSymValue() const
130{
131  return 0x1;
132}
133
134Stub* THMToTHMStub::doClone()
135{
136  return new THMToTHMStub(m_pData,
137                          m_Size,
138                          fixup_begin(),
139                          fixup_end(),
140                          m_bUsingThumb2);
141}
142