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136 lines
3.8 KiB
136 lines
3.8 KiB
//===- THMToARMStub.cpp ---------------------------------------------------===//
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//
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// The MCLinker Project
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "THMToARMStub.h"
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#include "ARMLDBackend.h"
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#include "mcld/Fragment/Relocation.h"
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#include "mcld/LD/LDSymbol.h"
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#include "mcld/LD/ResolveInfo.h"
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#include <llvm/Support/ELF.h>
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namespace mcld {
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//===----------------------------------------------------------------------===//
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// THMToARMStub
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//===----------------------------------------------------------------------===//
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const uint32_t THMToARMStub::PIC_TEMPLATE[] = {
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0x46c04778, // bx pc ... nop
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0xe59fc000, // ldr ip, [pc, #0]
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0xe08cf00f, // add pc, ip, pc
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0x0 // dcd R_ARM_REL32(X)
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};
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const uint32_t THMToARMStub::TEMPLATE[] = {
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0x46c04778, // bx pc ... nop
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0xe51ff004, // ldr pc, [pc, #-4]
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0x0 // dcd R_ARM_ABS32(X)
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};
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THMToARMStub::THMToARMStub(bool pIsOutputPIC, bool pUsingThumb2)
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: m_pData(NULL),
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m_Name("T2A_prototype"),
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m_Size(0x0),
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m_bUsingThumb2(pUsingThumb2) {
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if (pIsOutputPIC) {
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m_pData = PIC_TEMPLATE;
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m_Size = sizeof(PIC_TEMPLATE);
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addFixup(12u, -4, llvm::ELF::R_ARM_REL32);
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} else {
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m_pData = TEMPLATE;
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m_Size = sizeof(TEMPLATE);
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addFixup(8u, 0x0, llvm::ELF::R_ARM_ABS32);
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}
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}
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/// for doClone
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THMToARMStub::THMToARMStub(const uint32_t* pData,
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size_t pSize,
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const_fixup_iterator pBegin,
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const_fixup_iterator pEnd,
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bool pUsingThumb2)
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: m_pData(pData),
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m_Name("T2A_veneer"),
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m_Size(pSize),
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m_bUsingThumb2(pUsingThumb2) {
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for (const_fixup_iterator it = pBegin, ie = pEnd; it != ie; ++it)
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addFixup(**it);
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}
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THMToARMStub::~THMToARMStub() {
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}
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bool THMToARMStub::isMyDuty(const class Relocation& pReloc,
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uint64_t pSource,
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uint64_t pTargetSymValue) const {
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bool result = false;
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// Check if the branch target is ARM
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if ((pTargetSymValue & 0x1) == 0x0) {
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switch (pReloc.type()) {
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case llvm::ELF::R_ARM_THM_CALL: {
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// FIXME: Assuming blx is available (i.e., target is armv5 or above!)
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// then, we do not need a stub unless the branch target is too far.
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uint64_t dest = pTargetSymValue + pReloc.addend() + 4u;
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int64_t branch_offset = static_cast<int64_t>(dest) - pSource;
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if (m_bUsingThumb2) {
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if ((branch_offset > ARMGNULDBackend::THM2_MAX_FWD_BRANCH_OFFSET) ||
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(branch_offset < ARMGNULDBackend::THM2_MAX_BWD_BRANCH_OFFSET)) {
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result = true;
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break;
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}
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} else {
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if ((branch_offset > ARMGNULDBackend::THM_MAX_FWD_BRANCH_OFFSET) ||
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(branch_offset < ARMGNULDBackend::THM_MAX_BWD_BRANCH_OFFSET)) {
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result = true;
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break;
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}
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}
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break;
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}
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case llvm::ELF::R_ARM_THM_JUMP24: {
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// always need a stub to switch mode
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result = true;
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break;
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}
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default:
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break;
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}
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}
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return result;
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}
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const std::string& THMToARMStub::name() const {
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return m_Name;
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}
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const uint8_t* THMToARMStub::getContent() const {
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return reinterpret_cast<const uint8_t*>(m_pData);
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}
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size_t THMToARMStub::size() const {
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return m_Size;
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}
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size_t THMToARMStub::alignment() const {
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return 4u;
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}
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// for T bit of this stub
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uint64_t THMToARMStub::initSymValue() const {
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return 0x1;
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}
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Stub* THMToARMStub::doClone() {
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return new THMToARMStub(
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m_pData, m_Size, fixup_begin(), fixup_end(), m_bUsingThumb2);
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}
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} // namespace mcld
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