1//===- THMToARMStub.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 "THMToARMStub.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// THMToARMStub 22//===----------------------------------------------------------------------===// 23const uint32_t THMToARMStub::PIC_TEMPLATE[] = { 24 0x46c04778, // bx pc ... nop 25 0xe59fc000, // ldr ip, [pc, #0] 26 0xe08cf00f, // add pc, ip, pc 27 0x0 // dcd R_ARM_REL32(X) 28}; 29 30const uint32_t THMToARMStub::TEMPLATE[] = { 31 0x46c04778, // bx pc ... nop 32 0xe51ff004, // ldr pc, [pc, #-4] 33 0x0 // dcd R_ARM_ABS32(X) 34}; 35 36THMToARMStub::THMToARMStub(bool pIsOutputPIC, bool pUsingThumb2) 37 : m_pData(NULL), 38 m_Name("T2A_prototype"), 39 m_Size(0x0), 40 m_bUsingThumb2(pUsingThumb2) 41{ 42 if (pIsOutputPIC) { 43 m_pData = PIC_TEMPLATE; 44 m_Size = sizeof(PIC_TEMPLATE); 45 addFixup(12u, -4, llvm::ELF::R_ARM_REL32); 46 } else { 47 m_pData = TEMPLATE; 48 m_Size = sizeof(TEMPLATE); 49 addFixup(8u, 0x0, llvm::ELF::R_ARM_ABS32); 50 } 51} 52 53/// for doClone 54THMToARMStub::THMToARMStub(const uint32_t* pData, 55 size_t pSize, 56 const_fixup_iterator pBegin, 57 const_fixup_iterator pEnd, 58 bool pUsingThumb2) 59 : m_pData(pData), 60 m_Name("T2A_veneer"), 61 m_Size(pSize), 62 m_bUsingThumb2(pUsingThumb2) 63{ 64 for (const_fixup_iterator it = pBegin, ie = pEnd; it != ie; ++it) 65 addFixup(**it); 66} 67 68THMToARMStub::~THMToARMStub() 69{ 70} 71 72bool THMToARMStub::isMyDuty(const class Relocation& pReloc, 73 uint64_t pSource, 74 uint64_t pTargetSymValue) const 75{ 76 bool result = false; 77 // Check if the branch target is ARM 78 if ((pTargetSymValue & 0x1) == 0x0) { 79 switch (pReloc.type()) { 80 case llvm::ELF::R_ARM_THM_CALL: { 81 // FIXME: Assuming blx is available (i.e., target is armv5 or above!) 82 // then, we do not need a stub unless the branch target is too far. 83 uint64_t dest = pTargetSymValue + pReloc.addend() + 4u; 84 int64_t branch_offset = static_cast<int64_t>(dest) - pSource; 85 if (m_bUsingThumb2) { 86 if ((branch_offset > ARMGNULDBackend::THM2_MAX_FWD_BRANCH_OFFSET) || 87 (branch_offset < ARMGNULDBackend::THM2_MAX_BWD_BRANCH_OFFSET)) { 88 result = true; 89 break; 90 } 91 } else { 92 if ((branch_offset > ARMGNULDBackend::THM_MAX_FWD_BRANCH_OFFSET) || 93 (branch_offset < ARMGNULDBackend::THM_MAX_BWD_BRANCH_OFFSET)) { 94 result = true; 95 break; 96 } 97 } 98 break; 99 } 100 case llvm::ELF::R_ARM_THM_JUMP24: { 101 // always need a stub to switch mode 102 result = true; 103 break; 104 } 105 default: 106 break; 107 } 108 } 109 return result; 110} 111 112const std::string& THMToARMStub::name() const 113{ 114 return m_Name; 115} 116 117const uint8_t* THMToARMStub::getContent() const 118{ 119 return reinterpret_cast<const uint8_t*>(m_pData); 120} 121 122size_t THMToARMStub::size() const 123{ 124 return m_Size; 125} 126 127size_t THMToARMStub::alignment() const 128{ 129 return 4u; 130} 131 132// for T bit of this stub 133uint64_t THMToARMStub::initSymValue() const 134{ 135 return 0x1; 136} 137 138Stub* THMToARMStub::doClone() 139{ 140 return new THMToARMStub(m_pData, 141 m_Size, 142 fixup_begin(), 143 fixup_end(), 144 m_bUsingThumb2); 145} 146