RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
const ObjectFile &BaseTObj, const relocation_iterator &RI,
const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
const MachOObjectFile &Obj =
static_cast<const MachOObjectFile &>(BaseTObj);
MachO::any_relocation_info RelInfo =
Obj.getRelocation(RI->getRawDataRefImpl());
RelocationValueRef Value;
bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
if (IsExternal) {
symbol_iterator Symbol = RI->getSymbol();
StringRef TargetName;
Symbol->getName(TargetName);
SymbolTableMap::const_iterator SI =
GlobalSymbolTable.find(TargetName.data());
if (SI != GlobalSymbolTable.end()) {
Value.SectionID = SI->second.first;
Value.Offset = SI->second.second + RE.Addend;
} else {
Value.SymbolName = TargetName.data();
Value.Offset = RE.Addend;
}
} else {
SectionRef Sec = Obj.getRelocationSection(RelInfo);
bool IsCode = Sec.isText();
Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
uint64_t Addr = Sec.getAddress();
Value.Offset = RE.Addend - Addr;
}
return Value;
}
MCMachObjectSymbolizer::MCMachObjectSymbolizer(
MCContext &Ctx, std::unique_ptr<MCRelocationInfo> &RelInfo,
const MachOObjectFile *MOOF)
: MCObjectSymbolizer(Ctx, RelInfo, MOOF), MOOF(MOOF), StubsStart(0),
StubsCount(0), StubSize(0), StubsIndSymIndex(0) {
for (const SectionRef &Section : MOOF->sections()) {
StringRef Name;
Section.getName(Name);
if (Name == "__stubs") {
SectionRef StubsSec = Section;
if (MOOF->is64Bit()) {
MachO::section_64 S = MOOF->getSection64(StubsSec.getRawDataRefImpl());
StubsIndSymIndex = S.reserved1;
StubSize = S.reserved2;
} else {
MachO::section S = MOOF->getSection(StubsSec.getRawDataRefImpl());
StubsIndSymIndex = S.reserved1;
StubSize = S.reserved2;
}
assert(StubSize && "Mach-O stub entry size can't be zero!");
StubsSec.getAddress(StubsStart);
StubsSec.getSize(StubsCount);
StubsCount /= StubSize;
}
}
}
explicit section(const SectionRef& sec) {
StringRef name;
if(error_code err = sec.getName(name))
llvm_binary_fail(err);
this->name_ = name.str();
if (error_code err = sec.getAddress(this->addr_))
llvm_binary_fail(err);
if (error_code err = sec.getSize(this->size_))
llvm_binary_fail(err);
}
/// Given a relocation from __compact_unwind, consisting of the RelocationRef
/// and data being relocated, determine the best base Name and Addend to use for
/// display purposes.
///
/// 1. An Extern relocation will directly reference a symbol (and the data is
/// then already an addend), so use that.
/// 2. Otherwise the data is an offset in the object file's layout; try to find
// a symbol before it in the same section, and use the offset from there.
/// 3. Finally, if all that fails, fall back to an offset from the start of the
/// referenced section.
static void findUnwindRelocNameAddend(const MachOObjectFile *Obj,
std::map<uint64_t, SymbolRef> &Symbols,
const RelocationRef &Reloc,
uint64_t Addr,
StringRef &Name, uint64_t &Addend) {
if (Reloc.getSymbol() != Obj->symbol_end()) {
Reloc.getSymbol()->getName(Name);
Addend = Addr;
return;
}
auto RE = Obj->getRelocation(Reloc.getRawDataRefImpl());
SectionRef RelocSection = Obj->getRelocationSection(RE);
uint64_t SectionAddr;
RelocSection.getAddress(SectionAddr);
auto Sym = Symbols.upper_bound(Addr);
if (Sym == Symbols.begin()) {
// The first symbol in the object is after this reference, the best we can
// do is section-relative notation.
RelocSection.getName(Name);
Addend = Addr - SectionAddr;
return;
}
// Go back one so that SymbolAddress <= Addr.
--Sym;
section_iterator SymSection = Obj->section_end();
Sym->second.getSection(SymSection);
if (RelocSection == *SymSection) {
// There's a valid symbol in the same section before this reference.
Sym->second.getName(Name);
Addend = Addr - Sym->first;
return;
}
// There is a symbol before this reference, but it's in a different
// section. Probably not helpful to mention it, so use the section name.
RelocSection.getName(Name);
Addend = Addr - SectionAddr;
}
RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
const ObjectFile &BaseTObj, const relocation_iterator &RI,
const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
const MachOObjectFile &Obj =
static_cast<const MachOObjectFile &>(BaseTObj);
MachO::any_relocation_info RelInfo =
Obj.getRelocation(RI->getRawDataRefImpl());
RelocationValueRef Value;
bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
if (IsExternal) {
symbol_iterator Symbol = RI->getSymbol();
ErrorOr<StringRef> TargetNameOrErr = Symbol->getName();
if (std::error_code EC = TargetNameOrErr.getError())
report_fatal_error(EC.message());
StringRef TargetName = *TargetNameOrErr;
RTDyldSymbolTable::const_iterator SI =
GlobalSymbolTable.find(TargetName.data());
if (SI != GlobalSymbolTable.end()) {
const auto &SymInfo = SI->second;
Value.SectionID = SymInfo.getSectionID();
Value.Offset = SymInfo.getOffset() + RE.Addend;
} else {
Value.SymbolName = TargetName.data();
Value.Offset = RE.Addend;
}
} else {
SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
bool IsCode = Sec.isText();
Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
uint64_t Addr = Sec.getAddress();
Value.Offset = RE.Addend - Addr;
}
return Value;
}
void RuntimeDyldMachO::processRelocationRef(unsigned SectionID,
RelocationRef RelI,
ObjectImage &Obj,
ObjSectionToIDMap &ObjSectionToID,
const SymbolTableMap &Symbols,
StubMap &Stubs) {
const ObjectFile *OF = Obj.getObjectFile();
const MachOObjectFile *MachO = static_cast<const MachOObjectFile*>(OF);
MachO::any_relocation_info RE= MachO->getRelocation(RelI.getRawDataRefImpl());
uint32_t RelType = MachO->getAnyRelocationType(RE);
// FIXME: Properly handle scattered relocations.
// For now, optimistically skip these: they can often be ignored, as
// the static linker will already have applied the relocation, and it
// only needs to be reapplied if symbols move relative to one another.
// Note: This will fail horribly where the relocations *do* need to be
// applied, but that was already the case.
if (MachO->isRelocationScattered(RE))
return;
RelocationValueRef Value;
SectionEntry &Section = Sections[SectionID];
bool isExtern = MachO->getPlainRelocationExternal(RE);
bool IsPCRel = MachO->getAnyRelocationPCRel(RE);
unsigned Size = MachO->getAnyRelocationLength(RE);
uint64_t Offset;
RelI.getOffset(Offset);
uint8_t *LocalAddress = Section.Address + Offset;
unsigned NumBytes = 1 << Size;
uint64_t Addend = 0;
memcpy(&Addend, LocalAddress, NumBytes);
if (isExtern) {
// Obtain the symbol name which is referenced in the relocation
symbol_iterator Symbol = RelI.getSymbol();
StringRef TargetName;
Symbol->getName(TargetName);
// First search for the symbol in the local symbol table
SymbolTableMap::const_iterator lsi = Symbols.find(TargetName.data());
if (lsi != Symbols.end()) {
Value.SectionID = lsi->second.first;
Value.Addend = lsi->second.second + Addend;
} else {
// Search for the symbol in the global symbol table
SymbolTableMap::const_iterator gsi = GlobalSymbolTable.find(TargetName.data());
if (gsi != GlobalSymbolTable.end()) {
Value.SectionID = gsi->second.first;
Value.Addend = gsi->second.second + Addend;
} else {
Value.SymbolName = TargetName.data();
Value.Addend = Addend;
}
}
} else {
SectionRef Sec = MachO->getRelocationSection(RE);
bool IsCode = false;
Sec.isText(IsCode);
Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
uint64_t Addr;
Sec.getAddress(Addr);
Value.Addend = Addend - Addr;
if (IsPCRel)
Value.Addend += Offset + NumBytes;
}
if (Arch == Triple::x86_64 && (RelType == MachO::X86_64_RELOC_GOT ||
RelType == MachO::X86_64_RELOC_GOT_LOAD)) {
assert(IsPCRel);
assert(Size == 2);
StubMap::const_iterator i = Stubs.find(Value);
uint8_t *Addr;
if (i != Stubs.end()) {
Addr = Section.Address + i->second;
} else {
Stubs[Value] = Section.StubOffset;
uint8_t *GOTEntry = Section.Address + Section.StubOffset;
RelocationEntry RE(SectionID, Section.StubOffset,
MachO::X86_64_RELOC_UNSIGNED, 0, false, 3);
if (Value.SymbolName)
addRelocationForSymbol(RE, Value.SymbolName);
else
addRelocationForSection(RE, Value.SectionID);
Section.StubOffset += 8;
Addr = GOTEntry;
}
resolveRelocation(Section, Offset, (uint64_t)Addr,
MachO::X86_64_RELOC_UNSIGNED, Value.Addend, true, 2);
} else if (Arch == Triple::arm &&
(RelType & 0xf) == MachO::ARM_RELOC_BR24) {
// This is an ARM branch relocation, need to use a stub function.
// Look up for existing stub.
StubMap::const_iterator i = Stubs.find(Value);
if (i != Stubs.end())
resolveRelocation(Section, Offset,
(uint64_t)Section.Address + i->second,
RelType, 0, IsPCRel, Size);
else {
// Create a new stub function.
Stubs[Value] = Section.StubOffset;
uint8_t *StubTargetAddr = createStubFunction(Section.Address +
Section.StubOffset);
RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
MachO::GENERIC_RELOC_VANILLA, Value.Addend);
if (Value.SymbolName)
addRelocationForSymbol(RE, Value.SymbolName);
else
addRelocationForSection(RE, Value.SectionID);
resolveRelocation(Section, Offset,
(uint64_t)Section.Address + Section.StubOffset,
RelType, 0, IsPCRel, Size);
Section.StubOffset += getMaxStubSize();
}
} else {
RelocationEntry RE(SectionID, Offset, RelType, Value.Addend,
IsPCRel, Size);
if (Value.SymbolName)
addRelocationForSymbol(RE, Value.SymbolName);
else
addRelocationForSection(RE, Value.SectionID);
}
}
bool Decoder::dumpXDataRecord(const COFFObjectFile &COFF,
const SectionRef &Section,
uint64_t FunctionAddress, uint64_t VA) {
ArrayRef<uint8_t> Contents;
if (COFF.getSectionContents(COFF.getCOFFSection(Section), Contents))
return false;
uint64_t SectionVA = Section.getAddress();
uint64_t Offset = VA - SectionVA;
const ulittle32_t *Data =
reinterpret_cast<const ulittle32_t *>(Contents.data() + Offset);
const ExceptionDataRecord XData(Data);
DictScope XRS(SW, "ExceptionData");
SW.printNumber("FunctionLength", XData.FunctionLength() << 1);
SW.printNumber("Version", XData.Vers());
SW.printBoolean("ExceptionData", XData.X());
SW.printBoolean("EpiloguePacked", XData.E());
SW.printBoolean("Fragment", XData.F());
SW.printNumber(XData.E() ? "EpilogueOffset" : "EpilogueScopes",
XData.EpilogueCount());
SW.printNumber("ByteCodeLength",
static_cast<uint64_t>(XData.CodeWords() * sizeof(uint32_t)));
if (XData.E()) {
ArrayRef<uint8_t> UC = XData.UnwindByteCode();
if (!XData.F()) {
ListScope PS(SW, "Prologue");
decodeOpcodes(UC, 0, /*Prologue=*/true);
}
if (XData.EpilogueCount()) {
ListScope ES(SW, "Epilogue");
decodeOpcodes(UC, XData.EpilogueCount(), /*Prologue=*/false);
}
} else {
ArrayRef<ulittle32_t> EpilogueScopes = XData.EpilogueScopes();
ListScope ESS(SW, "EpilogueScopes");
for (const EpilogueScope ES : EpilogueScopes) {
DictScope ESES(SW, "EpilogueScope");
SW.printNumber("StartOffset", ES.EpilogueStartOffset());
SW.printNumber("Condition", ES.Condition());
SW.printNumber("EpilogueStartIndex", ES.EpilogueStartIndex());
ListScope Opcodes(SW, "Opcodes");
decodeOpcodes(XData.UnwindByteCode(), ES.EpilogueStartIndex(),
/*Prologue=*/false);
}
}
if (XData.X()) {
const uint32_t Address = XData.ExceptionHandlerRVA();
const uint32_t Parameter = XData.ExceptionHandlerParameter();
const size_t HandlerOffset = HeaderWords(XData)
+ (XData.E() ? 0 : XData.EpilogueCount())
+ XData.CodeWords();
ErrorOr<SymbolRef> Symbol =
getRelocatedSymbol(COFF, Section, HandlerOffset * sizeof(uint32_t));
if (!Symbol)
Symbol = getSymbol(COFF, Address, /*FunctionOnly=*/true);
StringRef Name;
if (Symbol)
Symbol->getName(Name);
ListScope EHS(SW, "ExceptionHandler");
SW.printString("Routine", formatSymbol(Name, Address));
SW.printHex("Parameter", Parameter);
}
return true;
}
uint64_t getAddr(const SectionRef &sec) { return sec.getAddress(); }
static bool SectionStartsBefore(const SectionRef &S, uint64_t Addr) {
uint64_t SAddr; S.getAddress(SAddr);
return SAddr < Addr;
}
