1//===- ARMToARMStub.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 "ARMToARMStub.h"
11#include "ARMLDBackend.h"
12
13#include "mcld/Fragment/Relocation.h"
14#include "mcld/LD/LDSymbol.h"
15#include "mcld/LD/ResolveInfo.h"
16
17#include <llvm/Support/ELF.h>
18
19namespace mcld {
20
21//===----------------------------------------------------------------------===//
22// ARMToARMStub
23//===----------------------------------------------------------------------===//
24const uint32_t ARMToARMStub::PIC_TEMPLATE[] = {
25    0xe59fc000,  // ldr   r12, [pc]
26    0xe08ff00c,  // add   pc, pc, ip
27    0x0          // dcd   R_ARM_REL32(X-4)
28};
29
30const uint32_t ARMToARMStub::TEMPLATE[] = {
31    0xe51ff004,  // ldr   pc, [pc, #-4]
32    0x0          // dcd   R_ARM_ABS32(X)
33};
34
35ARMToARMStub::ARMToARMStub(bool pIsOutputPIC)
36    : m_pData(NULL), m_Name("A2A_prototype"), m_Size(0x0) {
37  if (pIsOutputPIC) {
38    m_pData = PIC_TEMPLATE;
39    m_Size = sizeof(PIC_TEMPLATE);
40    addFixup(8u, -4, llvm::ELF::R_ARM_REL32);
41  } else {
42    m_pData = TEMPLATE;
43    m_Size = sizeof(TEMPLATE);
44    addFixup(4u, 0x0, llvm::ELF::R_ARM_ABS32);
45  }
46}
47
48/// for doClone
49ARMToARMStub::ARMToARMStub(const uint32_t* pData,
50                           size_t pSize,
51                           const_fixup_iterator pBegin,
52                           const_fixup_iterator pEnd)
53    : m_pData(pData), m_Name("A2A_veneer"), m_Size(pSize) {
54  for (const_fixup_iterator it = pBegin, ie = pEnd; it != ie; ++it)
55    addFixup(**it);
56}
57
58ARMToARMStub::~ARMToARMStub() {
59}
60
61bool ARMToARMStub::isMyDuty(const class Relocation& pReloc,
62                            uint64_t pSource,
63                            uint64_t pTargetSymValue) const {
64  bool result = false;
65  // Check if the branch target is ARM
66  if ((pTargetSymValue & 0x1) == 0x0) {
67    switch (pReloc.type()) {
68      case llvm::ELF::R_ARM_PC24:
69      case llvm::ELF::R_ARM_CALL:
70      case llvm::ELF::R_ARM_JUMP24:
71      case llvm::ELF::R_ARM_PLT32: {
72        // Check if the branch target is too far
73        uint64_t dest = pTargetSymValue + pReloc.addend() + 8u;
74        int64_t branch_offset = static_cast<int64_t>(dest) - pSource;
75        if ((branch_offset > ARMGNULDBackend::ARM_MAX_FWD_BRANCH_OFFSET) ||
76            (branch_offset < ARMGNULDBackend::ARM_MAX_BWD_BRANCH_OFFSET)) {
77          result = true;
78        }
79        break;
80      }
81      default:
82        break;
83    }
84  }
85  return result;
86}
87
88const std::string& ARMToARMStub::name() const {
89  return m_Name;
90}
91
92const uint8_t* ARMToARMStub::getContent() const {
93  return reinterpret_cast<const uint8_t*>(m_pData);
94}
95
96size_t ARMToARMStub::size() const {
97  return m_Size;
98}
99
100size_t ARMToARMStub::alignment() const {
101  return 4u;
102}
103
104Stub* ARMToARMStub::doClone() {
105  return new ARMToARMStub(m_pData, m_Size, fixup_begin(), fixup_end());
106}
107
108}  // namespace mcld
109