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