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[X86_64] Emit _GLOBAL_OFFSET_TABLE_ symbol for x86-64 #1123

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[X86_64] Emit _GLOBAL_OFFSET_TABLE_ symbol for x86-64 #1123

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1 change: 1 addition & 0 deletions include/eld/Target/GNULDBackend.h
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Original file line number Diff line number Diff line change
Expand Up @@ -932,6 +932,7 @@ class GNULDBackend {
virtual void addTargetSpecificSegments();

void addSectionInfo(LDSymbol *symbol, ELFSection *section);
LDSymbol *defineGlobalOffsetTableSymbol();

/// Returns the name of the common symbol associated with the section
/// 'commonSection'.
Expand Down
63 changes: 21 additions & 42 deletions lib/Target/AArch64/AArch64LDBackend.cpp
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Expand Up @@ -54,8 +54,7 @@ using namespace llvm;
//===----------------------------------------------------------------------===//
// AArch64LDBackend
//===----------------------------------------------------------------------===//
AArch64LDBackend::AArch64LDBackend(eld::Module &pModule,
TargetInfo *pInfo)
AArch64LDBackend::AArch64LDBackend(eld::Module &pModule, TargetInfo *pInfo)
: GNULDBackend(pModule, pInfo), m_pErrata843419Factory(nullptr),
m_pAArch64ErrataIslandFactory(nullptr), m_pRelocator(nullptr),
m_pDynamic(nullptr), m_pIRelativeStart(nullptr), m_pIRelativeEnd(nullptr),
Expand Down Expand Up @@ -109,24 +108,8 @@ void AArch64LDBackend::initTargetSections(ObjectBuilder &pBuilder) {
}

void AArch64LDBackend::initTargetSymbols() {
// Define the symbol _GLOBAL_OFFSET_TABLE_ if there is a symbol with the
// same name in input
auto SymbolName = "_GLOBAL_OFFSET_TABLE_";
if (LinkerConfig::Object != config().codeGenType()) {
m_pGOTSymbol =
m_Module.getIRBuilder()
->addSymbol<IRBuilder::AsReferred, IRBuilder::Resolve>(
m_Module.getInternalInput(Module::Script), SymbolName,
ResolveInfo::Object, ResolveInfo::Define, ResolveInfo::Local,
0x0, // size
0x0, // value
FragmentRef::null(), ResolveInfo::Hidden);
if (m_Module.getConfig().options().isSymbolTracingRequested() &&
m_Module.getConfig().options().traceSymbol(SymbolName))
config().raise(Diag::target_specific_symbol) << SymbolName;
if (m_pGOTSymbol)
m_pGOTSymbol->setShouldIgnore(false);
}
if (LinkerConfig::Object != config().codeGenType())
m_pGOTSymbol = defineGlobalOffsetTableSymbol();
}

bool AArch64LDBackend::initRelocator() {
Expand All @@ -136,8 +119,7 @@ bool AArch64LDBackend::initRelocator() {
return true;
}

bool AArch64LDBackend::processInputFiles(
std::vector<InputFile *> &Inputs) {
bool AArch64LDBackend::processInputFiles(std::vector<InputFile *> &Inputs) {
if (!m_pGPF)
return config().getDiagEngine()->diagnose();
for (auto &I : Inputs) {
Expand Down Expand Up @@ -220,8 +202,7 @@ void AArch64LDBackend::doPreLayout() {
m_ptbss = m_Module.getScript().sectionMap().find(".tbss");
}

void AArch64LDBackend::initSegmentFromLinkerScript(
ELFSegment *pSegment) {
void AArch64LDBackend::initSegmentFromLinkerScript(ELFSegment *pSegment) {
auto sect = pSegment->begin(), sectEnd = pSegment->end();
bool isPrevBSS = false;
bool hasMixedBSS = false;
Expand Down Expand Up @@ -260,8 +241,8 @@ void AArch64LDBackend::initSegmentFromLinkerScript(

AArch64ELFDynamic *AArch64LDBackend::dynamic() { return m_pDynamic; }

unsigned int AArch64LDBackend::getTargetSectionOrder(
const ELFSection &pSectHdr) const {
unsigned int
AArch64LDBackend::getTargetSectionOrder(const ELFSection &pSectHdr) const {
if (pSectHdr.name() == ".got") {
if (config().options().hasNow())
return SHO_RELRO;
Expand Down Expand Up @@ -349,9 +330,8 @@ void AArch64LDBackend::mayBeRelax(int pass, bool &pFinished) {
}

// Return whether this is a 3-insn erratum sequence.
bool AArch64LDBackend::isErratum843419Sequence(uint32_t insn1,
uint32_t insn2,
uint32_t insn3) {
bool AArch64LDBackend::isErratum843419Sequence(uint32_t insn1, uint32_t insn2,
uint32_t insn3) {
unsigned rt1, rt2;
bool load, pair;

Expand Down Expand Up @@ -462,7 +442,7 @@ bool AArch64LDBackend::scanErrata843419() {
}

void AArch64LDBackend::createErratum843419Stub(Fragment *frag,
uint32_t offset) {
uint32_t offset) {
BranchIsland *branchIsland = m_pErrata843419Factory->create(
frag, offset, *m_Module.getIRBuilder(), *m_pAArch64ErrataIslandFactory);
switch (config().options().getStripSymbolMode()) {
Expand Down Expand Up @@ -645,9 +625,9 @@ bool AArch64LDBackend::ltoNeedAssembler() {
return true;
}

bool AArch64LDBackend::ltoCallExternalAssembler(
const std::string &Input, std::string RelocModel,
const std::string &Output) {
bool AArch64LDBackend::ltoCallExternalAssembler(const std::string &Input,
std::string RelocModel,
const std::string &Output) {
bool traceLTO = config().options().traceLTO();

// Invoke assembler.
Expand Down Expand Up @@ -712,10 +692,8 @@ bool AArch64LDBackend::ltoCallExternalAssembler(
}

// Create GOT entry.
AArch64GOT *AArch64LDBackend::createGOT(GOT::GOTType T,
ELFObjectFile *Obj,
ResolveInfo *R,
bool SkipPLTRef) {
AArch64GOT *AArch64LDBackend::createGOT(GOT::GOTType T, ELFObjectFile *Obj,
ResolveInfo *R, bool SkipPLTRef) {

if (R != nullptr && ((config().options().isSymbolTracingRequested() &&
config().options().traceSymbol(*R)) ||
Expand Down Expand Up @@ -827,7 +805,8 @@ void AArch64LDBackend::recordPLT(ResolveInfo *I, AArch64PLT *P) {
m_PLTMap[I] = P;
}

Relocation *AArch64LDBackend::findRelativeReloc(const Relocation *pReloc) const {
Relocation *
AArch64LDBackend::findRelativeReloc(const Relocation *pReloc) const {
return m_RelativeRelocMap.lookup(pReloc);
}

Expand Down Expand Up @@ -894,7 +873,7 @@ ELFSection *AArch64LDBackend::mergeSection(ELFSection *S) {
// Read .note.gnu.property and extract features for pointer authentication.
template <class ELFT>
bool AArch64LDBackend::readGNUProperty(InputFile &pInput, ELFSection *S,
uint32_t &featureSet) {
uint32_t &featureSet) {
using Elf_Nhdr = typename ELFT::Nhdr;
using Elf_Note = typename ELFT::Note;

Expand Down Expand Up @@ -973,10 +952,10 @@ namespace eld {
//===----------------------------------------------------------------------===//
GNULDBackend *createAArch64LDBackend(Module &pModule) {
if (pModule.getConfig().targets().triple().isOSLinux())
return make<AArch64LDBackend>(
pModule, make<AArch64LinuxInfo>(pModule.getConfig()));
return make<AArch64LDBackend>(pModule,
make<AArch64LinuxInfo>(pModule.getConfig()));
return make<AArch64LDBackend>(pModule,
make<AArch64Info>(pModule.getConfig()));
make<AArch64Info>(pModule.getConfig()));
}

uint64_t AArch64LDBackend::StaticTCBSize = 0x10;
Expand Down
31 changes: 7 additions & 24 deletions lib/Target/ARM/ARMLDBackend.cpp
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Expand Up @@ -126,31 +126,15 @@ void ARMGNULDBackend::initTargetSections(ObjectBuilder &pBuilder) {
}

void ARMGNULDBackend::initTargetSymbols() {
// Define the symbol _GLOBAL_OFFSET_TABLE_ if there is a symbol with the
// same name in input
auto SymbolName = "_GLOBAL_OFFSET_TABLE_";
if (LinkerConfig::Object != config().codeGenType()) {
m_pGOTSymbol =
m_Module.getIRBuilder()
->addSymbol<IRBuilder::AsReferred, IRBuilder::Resolve>(
m_Module.getInternalInput(Module::Script), SymbolName,
ResolveInfo::Object, ResolveInfo::Define, ResolveInfo::Local,
0x0, // size
0x0, // value
FragmentRef::null(), ResolveInfo::Hidden);
if (m_Module.getConfig().options().isSymbolTracingRequested() &&
m_Module.getConfig().options().traceSymbol(SymbolName))
config().raise(Diag::target_specific_symbol) << SymbolName;
if (m_pGOTSymbol)
m_pGOTSymbol->setShouldIgnore(false);
}
if (LinkerConfig::Object != config().codeGenType())
m_pGOTSymbol = defineGlobalOffsetTableSymbol();

// If linker script, lets not add this symbol.
if (m_Module.getScript().linkerScriptHasSectionsCommand())
return;

const NamePool& NP = m_Module.getNamePool();
SymbolName = "__exidx_start";
const NamePool &NP = m_Module.getNamePool();
const char *SymbolName = "__exidx_start";
const ResolveInfo *EXIDXStartInfo = NP.findInfo(SymbolName);
if (EXIDXStartInfo && EXIDXStartInfo->isUndef()) {
m_pEXIDXStart =
Expand Down Expand Up @@ -218,8 +202,7 @@ void ARMGNULDBackend::doPreLayout() {
if (isMicroController() &&
((config().codeGenType() == LinkerConfig::DynObj) ||
(config().options().isPIE()))) {
config().raise(Diag::not_supported) << "SharedLibrary/PIE"
<< "Cortex-M";
config().raise(Diag::not_supported) << "SharedLibrary/PIE" << "Cortex-M";
m_Module.setFailure(true);
return;
}
Expand Down Expand Up @@ -517,7 +500,7 @@ bool ARMGNULDBackend::readSection(InputFile &pInput, ELFSection *S) {
LayoutInfo *layoutInfo = getModule().getLayoutInfo();
if (layoutInfo)
layoutInfo->recordFragment(m_pARMAttributeSection->getInputFile(),
m_pARMAttributeSection, AttributeFragment);
m_pARMAttributeSection, AttributeFragment);
}
AttributeFragment->updateAttributes(
Region, m_Module, llvm::dyn_cast<ObjectFile>(&pInput), config());
Expand Down Expand Up @@ -1192,7 +1175,7 @@ void ARMGNULDBackend::finishAssignOutputSections() {
LayoutInfo *layoutInfo = getModule().getLayoutInfo();
if (layoutInfo)
layoutInfo->recordFragment(m_pRegionTableSection->getInputFile(),
m_pRegionTableSection, m_pRegionTableFragment);
m_pRegionTableSection, m_pRegionTableFragment);
}

// Update the RegionTable with updated information from the Backend.
Expand Down
16 changes: 16 additions & 0 deletions lib/Target/GNULDBackend.cpp
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Expand Up @@ -4885,6 +4885,22 @@ size_t GNULDBackend::getGOTSymbolAddr() const {
return (fragRef->getOutputOffset(m_Module) + section->addr());
}

LDSymbol *GNULDBackend::defineGlobalOffsetTableSymbol() {
const std::string SymbolName = "_GLOBAL_OFFSET_TABLE_";
LDSymbol *Sym =
m_Module.getIRBuilder()
->addSymbol<IRBuilder::AsReferred, IRBuilder::Resolve>(
m_Module.getInternalInput(Module::Script), SymbolName,
ResolveInfo::Object, ResolveInfo::Define, ResolveInfo::Local, 0x0,
0x0, FragmentRef::null(), ResolveInfo::Hidden);
if (Sym)
Sym->setShouldIgnore(false);
if (m_Module.getConfig().options().isSymbolTracingRequested() &&
m_Module.getConfig().options().traceSymbol(SymbolName))
config().raise(Diag::target_specific_symbol) << SymbolName;
return Sym;
}

std::string
GNULDBackend::getCommonSymbolName(const CommonELFSection *commonSection) const {
llvm::StringRef sectionName = commonSection->name();
Expand Down
24 changes: 5 additions & 19 deletions lib/Target/Hexagon/HexagonLDBackend.cpp
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Expand Up @@ -250,8 +250,8 @@ void HexagonLDBackend::createAttributeSection() {
AttributeFragment = make<HexagonAttributeFragment>(AttributeSection);
AttributeSection->addFragment(AttributeFragment);
if (auto *layoutInfo = getModule().getLayoutInfo())
layoutInfo->recordFragment(AttributeSection->getInputFile(), AttributeSection,
AttributeFragment);
layoutInfo->recordFragment(AttributeSection->getInputFile(),
AttributeSection, AttributeFragment);
}

void HexagonLDBackend::initTargetSections(ObjectBuilder &pBuilder) {
Expand Down Expand Up @@ -314,23 +314,9 @@ void HexagonLDBackend::initTargetSections(ObjectBuilder &pBuilder) {
void HexagonLDBackend::initTargetSymbols() {
if (config().codeGenType() == LinkerConfig::Object)
return;
auto SymbolName = "_GLOBAL_OFFSET_TABLE_";
// Define the symbol _GLOBAL_OFFSET_TABLE_ if there is a symbol with the
// same name in input
m_pGOTSymbol =
m_Module.getIRBuilder()
->addSymbol<IRBuilder::AsReferred, IRBuilder::Resolve>(
m_Module.getInternalInput(Module::Script), SymbolName,
ResolveInfo::Object, ResolveInfo::Define, ResolveInfo::Local,
0x0, // size
0x0, // value
FragmentRef::null(), ResolveInfo::Hidden);
if (m_pGOTSymbol)
m_pGOTSymbol->setShouldIgnore(false);
if (m_Module.getConfig().options().isSymbolTracingRequested() &&
m_Module.getConfig().options().traceSymbol(SymbolName))
config().raise(Diag::target_specific_symbol) << SymbolName;
SymbolName = "___end";
m_pGOTSymbol = defineGlobalOffsetTableSymbol();

const char *SymbolName = "___end";
m_pEndOfImage = m_Module.getNamePool().findSymbol(SymbolName);
if (!m_pEndOfImage)
m_pEndOfImage =
Expand Down
36 changes: 21 additions & 15 deletions lib/Target/RISCV/RISCVLDBackend.cpp
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Expand Up @@ -110,7 +110,7 @@ void RISCVLDBackend::initTargetSections(ObjectBuilder &pBuilder) {
LayoutInfo *layoutInfo = getModule().getLayoutInfo();
if (layoutInfo)
layoutInfo->recordFragment(m_pRISCVAttributeSection->getInputFile(),
m_pRISCVAttributeSection, AttributeFragment);
m_pRISCVAttributeSection, AttributeFragment);
if (LinkerConfig::Object == config().codeGenType())
return;

Expand All @@ -135,7 +135,8 @@ void RISCVLDBackend::initPatchSections(ELFObjectFile &InputFile) {
void RISCVLDBackend::initTargetSymbols() {
if (config().codeGenType() == LinkerConfig::Object)
return;
// Do not create another __global_pointer$ when linking a patch.
m_pGOTSymbol = defineGlobalOffsetTableSymbol();

if (config().options().getPatchBase())
return;
if (m_Module.getScript().linkerScriptHasSectionsCommand()) {
Expand Down Expand Up @@ -312,7 +313,8 @@ bool RISCVLDBackend::doRelaxationCall(Relocation *reloc) {
->getInput()
->decoratedPath();

region->replaceInstruction(offset, reloc, reinterpret_cast<uint8_t *>(&c_j), 2);
region->replaceInstruction(offset, reloc, reinterpret_cast<uint8_t *>(&c_j),
2);
reloc->setTargetData(c_j);
reloc->setType(llvm::ELF::R_RISCV_RVC_JUMP);
relaxDeleteBytes("RISCV_CALL_C", *region, offset + 2, 6,
Expand All @@ -325,7 +327,8 @@ bool RISCVLDBackend::doRelaxationCall(Relocation *reloc) {
// Replace the instruction to JAL
uint32_t jal = 0x6fu | rd << 7;

region->replaceInstruction(offset, reloc, reinterpret_cast<uint8_t *>(&jal), 4);
region->replaceInstruction(offset, reloc, reinterpret_cast<uint8_t *>(&jal),
4);
reloc->setTargetData(jal);
reloc->setType(llvm::ELF::R_RISCV_JAL);
// Delete the next instruction
Expand All @@ -344,7 +347,8 @@ bool RISCVLDBackend::doRelaxationCall(Relocation *reloc) {
const char *msg =
(rd == 1) ? "R_RISCV_CALL_QC_E_JAL" : "R_RISCV_CALL_QC_E_J";

region->replaceInstruction(offset, reloc, reinterpret_cast<uint8_t *>(&qc_e_j), 6);
region->replaceInstruction(offset, reloc,
reinterpret_cast<uint8_t *>(&qc_e_j), 6);
reloc->setTargetData(qc_e_j);
reloc->setType(ELF::riscv::internal::R_RISCV_QC_E_CALL_PLT);
relaxDeleteBytes(msg, *region, offset + 6, 2, reloc->symInfo()->name());
Expand Down Expand Up @@ -405,26 +409,26 @@ bool RISCVLDBackend::doRelaxationQCCall(Relocation *reloc) {
->getInput()
->decoratedPath();

region->replaceInstruction(offset, reloc, reinterpret_cast<uint8_t *>(&compressed), 2);
region->replaceInstruction(offset, reloc,
reinterpret_cast<uint8_t *>(&compressed), 2);
// Replace the reloc to R_RISCV_RVC_JUMP
reloc->setType(llvm::ELF::R_RISCV_RVC_JUMP);
reloc->setTargetData(compressed);
relaxDeleteBytes(msg, *region, offset + 2, 4,
reloc->symInfo()->name());
relaxDeleteBytes(msg, *region, offset + 2, 4, reloc->symInfo()->name());
return true;
}

// Replace the instruction to JAL
unsigned rd = isTailCall ? /*x0*/ 0 : /*ra*/ 1;
uint32_t jal_instr = 0x6fu | rd << 7;
region->replaceInstruction(offset, reloc, reinterpret_cast<uint8_t *>(&jal_instr), 4);
region->replaceInstruction(offset, reloc,
reinterpret_cast<uint8_t *>(&jal_instr), 4);
// Replace the reloc to R_RISCV_JAL
reloc->setType(llvm::ELF::R_RISCV_JAL);
reloc->setTargetData(jal_instr);
// Delete the next instruction
const char *msg = isTailCall ? "RISCV_QC_E_J" : "RISCV_QC_E_JAL";
relaxDeleteBytes(msg, *region, offset + 4, 2,
reloc->symInfo()->name());
relaxDeleteBytes(msg, *region, offset + 4, 2, reloc->symInfo()->name());

return true;
}
Expand Down Expand Up @@ -621,7 +625,8 @@ bool RISCVLDBackend::doRelaxationQCELi(Relocation *reloc, Relocator::DWord G) {
if (canRelaxQcLi) {
uint32_t qc_li = 0x0000001bu | rd << 7;

region->replaceInstruction(offset, reloc, reinterpret_cast<uint8_t *>(&qc_li), 4);
region->replaceInstruction(offset, reloc,
reinterpret_cast<uint8_t *>(&qc_li), 4);
reloc->setTargetData(qc_li);
reloc->setType(ELF::riscv::internal::R_RISCV_QC_ABS20_U);
relaxDeleteBytes(msg, *region, offset + 4, 2, reloc->symInfo()->name());
Expand All @@ -633,7 +638,8 @@ bool RISCVLDBackend::doRelaxationQCELi(Relocation *reloc, Relocator::DWord G) {
unsigned rs = 3; // x3 = gp
uint32_t addi = 0x00000013u | (rd << 7) | (rs << 15);

region->replaceInstruction(offset, reloc, reinterpret_cast<uint8_t *>(&addi), 4);
region->replaceInstruction(offset, reloc,
reinterpret_cast<uint8_t *>(&addi), 4);
reloc->setTargetData(addi);
reloc->setType(ELF::riscv::internal::R_RISCV_GPREL_I);
relaxDeleteBytes(msg, *region, offset + 4, 2, reloc->symInfo()->name());
Expand Down Expand Up @@ -669,8 +675,8 @@ bool RISCVLDBackend::doRelaxationTLSDESC(Relocation &R, bool Relax) {
// Otherwise, the instruction is replaced with a NOP.
reportMissedRelaxation(RelaxType, *region, offset, 4, Sym.name());
uint32_t NOPi32 = static_cast<uint32_t>(NOP);
region->replaceInstruction(
offset, &R, reinterpret_cast<uint8_t *>(&NOPi32), 4);
region->replaceInstruction(offset, &R,
reinterpret_cast<uint8_t *>(&NOPi32), 4);
}
R.setType(llvm::ELF::R_RISCV_NONE);
return Relaxed;
Expand Down
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