MCSectionELF *MCContext::createELFSectionImpl(StringRef Section, unsigned Type,
unsigned Flags, SectionKind K,
unsigned EntrySize,
const MCSymbolELF *Group,
unsigned UniqueID,
const MCSymbolELF *Associated) {
MCSymbolELF *R;
MCSymbol *&Sym = Symbols[Section];
// A section symbol can not redefine regular symbols. There may be multiple
// sections with the same name, in which case the first such section wins.
if (Sym && Sym->isDefined() &&
(!Sym->isInSection() || Sym->getSection().getBeginSymbol() != Sym))
reportError(SMLoc(), "invalid symbol redefinition");
if (Sym && Sym->isUndefined()) {
R = cast<MCSymbolELF>(Sym);
} else {
auto NameIter = UsedNames.insert(std::make_pair(Section, false)).first;
R = new (&*NameIter, *this) MCSymbolELF(&*NameIter, /*isTemporary*/ false);
if (!Sym)
Sym = R;
}
R->setBinding(ELF::STB_LOCAL);
R->setType(ELF::STT_SECTION);
auto *Ret = new (ELFAllocator.Allocate()) MCSectionELF(
Section, Type, Flags, K, EntrySize, Group, UniqueID, R, Associated);
auto *F = new MCDataFragment();
Ret->getFragmentList().insert(Ret->begin(), F);
F->setParent(Ret);
R->setFragment(F);
return Ret;
}
void AMDGPUTargetELFStreamer::EmitAMDGPUHsaProgramScopeGlobal(
StringRef GlobalName) {
MCSymbolELF *Symbol = cast<MCSymbolELF>(
getStreamer().getContext().getOrCreateSymbol(GlobalName));
Symbol->setType(ELF::STT_OBJECT);
Symbol->setBinding(ELF::STB_GLOBAL);
}
bool ELFObjectWriter::isInSymtab(const MCAsmLayout &Layout,
const MCSymbolELF &Symbol, bool Used,
bool Renamed) {
if (Symbol.isVariable()) {
const MCExpr *Expr = Symbol.getVariableValue();
if (const MCSymbolRefExpr *Ref = dyn_cast<MCSymbolRefExpr>(Expr)) {
if (Ref->getKind() == MCSymbolRefExpr::VK_WEAKREF)
return false;
}
}
if (Used)
return true;
if (Renamed)
return false;
if (Symbol.isVariable() && Symbol.isUndefined()) {
// FIXME: this is here just to diagnose the case of a var = commmon_sym.
Layout.getBaseSymbol(Symbol);
return false;
}
if (Symbol.isUndefined() && !Symbol.isBindingSet())
return false;
if (Symbol.isTemporary())
return false;
if (Symbol.getType() == ELF::STT_SECTION)
return false;
return true;
}
// True if the assembler knows nothing about the final value of the symbol.
// This doesn't cover the comdat issues, since in those cases the assembler
// can at least know that all symbols in the section will move together.
static bool isWeak(const MCSymbolELF &Sym) {
if (Sym.getType() == ELF::STT_GNU_IFUNC)
return true;
switch (Sym.getBinding()) {
default:
llvm_unreachable("Unknown binding");
case ELF::STB_LOCAL:
return false;
case ELF::STB_GLOBAL:
return false;
case ELF::STB_WEAK:
case ELF::STB_GNU_UNIQUE:
return true;
}
}
void TargetLoweringObjectFileELF::emitPersonalityValue(
MCStreamer &Streamer, const DataLayout &DL, const MCSymbol *Sym) const {
SmallString<64> NameData("DW.ref.");
NameData += Sym->getName();
MCSymbolELF *Label =
cast<MCSymbolELF>(getContext().getOrCreateSymbol(NameData));
Streamer.EmitSymbolAttribute(Label, MCSA_Hidden);
Streamer.EmitSymbolAttribute(Label, MCSA_Weak);
unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP;
MCSection *Sec = getContext().getELFNamedSection(".data", Label->getName(),
ELF::SHT_PROGBITS, Flags, 0);
unsigned Size = DL.getPointerSize();
Streamer.SwitchSection(Sec);
Streamer.EmitValueToAlignment(DL.getPointerABIAlignment());
Streamer.EmitSymbolAttribute(Label, MCSA_ELF_TypeObject);
const MCExpr *E = MCConstantExpr::create(Size, getContext());
Streamer.emitELFSize(Label, E);
Streamer.EmitLabel(Label);
Streamer.EmitSymbolValue(Sym, Size);
}
void AMDGPUTargetELFStreamer::EmitAmdhsaKernelDescriptor(
const MCSubtargetInfo &STI, StringRef KernelName,
const amdhsa::kernel_descriptor_t &KernelDescriptor, uint64_t NextVGPR,
uint64_t NextSGPR, bool ReserveVCC, bool ReserveFlatScr,
bool ReserveXNACK) {
auto &Streamer = getStreamer();
auto &Context = Streamer.getContext();
MCSymbolELF *KernelDescriptorSymbol = cast<MCSymbolELF>(
Context.getOrCreateSymbol(Twine(KernelName) + Twine(".kd")));
KernelDescriptorSymbol->setBinding(ELF::STB_GLOBAL);
KernelDescriptorSymbol->setType(ELF::STT_OBJECT);
KernelDescriptorSymbol->setSize(
MCConstantExpr::create(sizeof(KernelDescriptor), Context));
MCSymbolELF *KernelCodeSymbol = cast<MCSymbolELF>(
Context.getOrCreateSymbol(Twine(KernelName)));
KernelCodeSymbol->setBinding(ELF::STB_LOCAL);
Streamer.EmitLabel(KernelDescriptorSymbol);
Streamer.EmitBytes(StringRef(
(const char*)&(KernelDescriptor),
offsetof(amdhsa::kernel_descriptor_t, kernel_code_entry_byte_offset)));
// FIXME: Remove the use of VK_AMDGPU_REL64 in the expression below. The
// expression being created is:
// (start of kernel code) - (start of kernel descriptor)
// It implies R_AMDGPU_REL64, but ends up being R_AMDGPU_ABS64.
Streamer.EmitValue(MCBinaryExpr::createSub(
MCSymbolRefExpr::create(
KernelCodeSymbol, MCSymbolRefExpr::VK_AMDGPU_REL64, Context),
MCSymbolRefExpr::create(
KernelDescriptorSymbol, MCSymbolRefExpr::VK_None, Context),
Context),
sizeof(KernelDescriptor.kernel_code_entry_byte_offset));
Streamer.EmitBytes(StringRef(
(const char*)&(KernelDescriptor) +
offsetof(amdhsa::kernel_descriptor_t, kernel_code_entry_byte_offset) +
sizeof(KernelDescriptor.kernel_code_entry_byte_offset),
sizeof(KernelDescriptor) -
offsetof(amdhsa::kernel_descriptor_t, kernel_code_entry_byte_offset) -
sizeof(KernelDescriptor.kernel_code_entry_byte_offset)));
}
void AMDGPUTargetELFStreamer::EmitAmdhsaKernelDescriptor(
const MCSubtargetInfo &STI, StringRef KernelName,
const amdhsa::kernel_descriptor_t &KernelDescriptor, uint64_t NextVGPR,
uint64_t NextSGPR, bool ReserveVCC, bool ReserveFlatScr,
bool ReserveXNACK) {
auto &Streamer = getStreamer();
auto &Context = Streamer.getContext();
MCSymbolELF *KernelCodeSymbol = cast<MCSymbolELF>(
Context.getOrCreateSymbol(Twine(KernelName)));
MCSymbolELF *KernelDescriptorSymbol = cast<MCSymbolELF>(
Context.getOrCreateSymbol(Twine(KernelName) + Twine(".kd")));
// Copy kernel descriptor symbol's binding, other and visibility from the
// kernel code symbol.
KernelDescriptorSymbol->setBinding(KernelCodeSymbol->getBinding());
KernelDescriptorSymbol->setOther(KernelCodeSymbol->getOther());
KernelDescriptorSymbol->setVisibility(KernelCodeSymbol->getVisibility());
// Kernel descriptor symbol's type and size are fixed.
KernelDescriptorSymbol->setType(ELF::STT_OBJECT);
KernelDescriptorSymbol->setSize(
MCConstantExpr::create(sizeof(KernelDescriptor), Context));
// The visibility of the kernel code symbol must be protected or less to allow
// static relocations from the kernel descriptor to be used.
if (KernelCodeSymbol->getVisibility() == ELF::STV_DEFAULT)
KernelCodeSymbol->setVisibility(ELF::STV_PROTECTED);
Streamer.EmitLabel(KernelDescriptorSymbol);
Streamer.EmitBytes(StringRef(
(const char*)&(KernelDescriptor),
offsetof(amdhsa::kernel_descriptor_t, kernel_code_entry_byte_offset)));
// FIXME: Remove the use of VK_AMDGPU_REL64 in the expression below. The
// expression being created is:
// (start of kernel code) - (start of kernel descriptor)
// It implies R_AMDGPU_REL64, but ends up being R_AMDGPU_ABS64.
Streamer.EmitValue(MCBinaryExpr::createSub(
MCSymbolRefExpr::create(
KernelCodeSymbol, MCSymbolRefExpr::VK_AMDGPU_REL64, Context),
MCSymbolRefExpr::create(
KernelDescriptorSymbol, MCSymbolRefExpr::VK_None, Context),
Context),
sizeof(KernelDescriptor.kernel_code_entry_byte_offset));
Streamer.EmitBytes(StringRef(
(const char*)&(KernelDescriptor) +
offsetof(amdhsa::kernel_descriptor_t, kernel_code_entry_byte_offset) +
sizeof(KernelDescriptor.kernel_code_entry_byte_offset),
sizeof(KernelDescriptor) -
offsetof(amdhsa::kernel_descriptor_t, kernel_code_entry_byte_offset) -
sizeof(KernelDescriptor.kernel_code_entry_byte_offset)));
}
void AMDGPUTargetELFStreamer::EmitAMDGPUSymbolType(StringRef SymbolName,
unsigned Type) {
MCSymbolELF *Symbol = cast<MCSymbolELF>(
getStreamer().getContext().getOrCreateSymbol(SymbolName));
Symbol->setType(Type);
}