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 <llvm/Support/ELF.h>
14 #include <mcld/LD/ResolveInfo.h>
15 #include <mcld/LD/LDSymbol.h>
16 #include <mcld/Fragment/Relocation.h>
17
18 using namespace mcld;
19
20 //===----------------------------------------------------------------------===//
21 // ARMToARMStub
22 //===----------------------------------------------------------------------===//
23 const uint32_t ARMToARMStub::PIC_TEMPLATE[] = {
24 0xe59fc000, // ldr r12, [pc]
25 0xe08ff00c, // add pc, pc, ip
26 0x0 // dcd R_ARM_REL32(X-4)
27 };
28
29 const uint32_t ARMToARMStub::TEMPLATE[] = {
30 0xe51ff004, // ldr pc, [pc, #-4]
31 0x0 // dcd R_ARM_ABS32(X)
32 };
33
ARMToARMStub(bool pIsOutputPIC)34 ARMToARMStub::ARMToARMStub(bool pIsOutputPIC)
35 : m_pData(NULL), m_Name("A2A_prototype"), m_Size(0x0)
36 {
37 if (pIsOutputPIC) {
38 m_pData = PIC_TEMPLATE;
39 m_Size = sizeof(PIC_TEMPLATE);
40 addFixup(8u, -4, llvm::ELF::R_ARM_REL32);
41 }
42 else {
43 m_pData = TEMPLATE;
44 m_Size = sizeof(TEMPLATE);
45 addFixup(4u, 0x0, llvm::ELF::R_ARM_ABS32);
46 }
47 }
48
49 /// for doClone
ARMToARMStub(const uint32_t * pData,size_t pSize,const_fixup_iterator pBegin,const_fixup_iterator pEnd)50 ARMToARMStub::ARMToARMStub(const uint32_t* pData,
51 size_t pSize,
52 const_fixup_iterator pBegin,
53 const_fixup_iterator pEnd)
54 : m_pData(pData), m_Name("A2A_veneer"), m_Size(pSize)
55 {
56 for (const_fixup_iterator it = pBegin, ie = pEnd; it != ie; ++it)
57 addFixup(**it);
58 }
59
~ARMToARMStub()60 ARMToARMStub::~ARMToARMStub()
61 {
62 }
63
isMyDuty(const class Relocation & pReloc,uint64_t pSource,uint64_t pTargetSymValue) const64 bool ARMToARMStub::isMyDuty(const class Relocation& pReloc,
65 uint64_t pSource,
66 uint64_t pTargetSymValue) const
67 {
68 bool result = false;
69 // Check if the branch target is ARM
70 if ((pTargetSymValue & 0x1) == 0x0) {
71 switch (pReloc.type()) {
72 case llvm::ELF::R_ARM_PC24:
73 case llvm::ELF::R_ARM_CALL:
74 case llvm::ELF::R_ARM_JUMP24:
75 case llvm::ELF::R_ARM_PLT32: {
76 // Check if the branch target is too far
77 uint64_t dest = pTargetSymValue + pReloc.addend() + 8u;
78 int64_t branch_offset = static_cast<int64_t>(dest) - pSource;
79 if ((branch_offset > ARMGNULDBackend::ARM_MAX_FWD_BRANCH_OFFSET) ||
80 (branch_offset < ARMGNULDBackend::ARM_MAX_BWD_BRANCH_OFFSET)) {
81 result = true;
82 }
83 break;
84 }
85 default:
86 break;
87 }
88 }
89 return result;
90 }
91
name() const92 const std::string& ARMToARMStub::name() const
93 {
94 return m_Name;
95 }
96
getContent() const97 const uint8_t* ARMToARMStub::getContent() const
98 {
99 return reinterpret_cast<const uint8_t*>(m_pData);
100 }
101
size() const102 size_t ARMToARMStub::size() const
103 {
104 return m_Size;
105 }
106
alignment() const107 size_t ARMToARMStub::alignment() const
108 {
109 return 4u;
110 }
111
doClone()112 Stub* ARMToARMStub::doClone()
113 {
114 return new ARMToARMStub(m_pData, m_Size, fixup_begin(), fixup_end());
115 }
116