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llvm-project/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp

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//===-- RuntimeDyldMachO.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-=//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Implementation of the MC-JIT runtime dynamic linker.
//
//===----------------------------------------------------------------------===//
#include "RuntimeDyldMachO.h"
#include "Targets/RuntimeDyldMachOAArch64.h"
#include "Targets/RuntimeDyldMachOARM.h"
#include "Targets/RuntimeDyldMachOI386.h"
#include "Targets/RuntimeDyldMachOX86_64.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
using namespace llvm;
using namespace llvm::object;
#define DEBUG_TYPE "dyld"
namespace {
class LoadedMachOObjectInfo final
: public LoadedObjectInfoHelper<LoadedMachOObjectInfo,
RuntimeDyld::LoadedObjectInfo> {
public:
LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld,
ObjSectionToIDMap ObjSecToIDMap)
: LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
OwningBinary<ObjectFile>
getObjectForDebug(const ObjectFile &Obj) const override {
return OwningBinary<ObjectFile>();
}
};
}
namespace llvm {
int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
unsigned NumBytes = 1 << RE.Size;
uint8_t *Src = Sections[RE.SectionID].getAddress() + RE.Offset;
return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
}
Expected<relocation_iterator>
RuntimeDyldMachO::processScatteredVANILLA(
unsigned SectionID, relocation_iterator RelI,
const ObjectFile &BaseObjT,
RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID,
bool TargetIsLocalThumbFunc) {
const MachOObjectFile &Obj =
static_cast<const MachOObjectFile&>(BaseObjT);
MachO::any_relocation_info RE =
Obj.getRelocation(RelI->getRawDataRefImpl());
SectionEntry &Section = Sections[SectionID];
uint32_t RelocType = Obj.getAnyRelocationType(RE);
bool IsPCRel = Obj.getAnyRelocationPCRel(RE);
unsigned Size = Obj.getAnyRelocationLength(RE);
uint64_t Offset = RelI->getOffset();
uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
unsigned NumBytes = 1 << Size;
int64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);
unsigned SymbolBaseAddr = Obj.getScatteredRelocationValue(RE);
section_iterator TargetSI = getSectionByAddress(Obj, SymbolBaseAddr);
assert(TargetSI != Obj.section_end() && "Can't find section for symbol");
uint64_t SectionBaseAddr = TargetSI->getAddress();
SectionRef TargetSection = *TargetSI;
bool IsCode = TargetSection.isText();
uint32_t TargetSectionID = ~0U;
if (auto TargetSectionIDOrErr =
findOrEmitSection(Obj, TargetSection, IsCode, ObjSectionToID))
TargetSectionID = *TargetSectionIDOrErr;
else
return TargetSectionIDOrErr.takeError();
Addend -= SectionBaseAddr;
RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
R.IsTargetThumbFunc = TargetIsLocalThumbFunc;
addRelocationForSection(R, TargetSectionID);
return ++RelI;
}
Expected<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;
if (auto TargetNameOrErr = Symbol->getName())
TargetName = *TargetNameOrErr;
else
return TargetNameOrErr.takeError();
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();
if (auto SectionIDOrErr = findOrEmitSection(Obj, Sec, IsCode,
ObjSectionToID))
Value.SectionID = *SectionIDOrErr;
else
return SectionIDOrErr.takeError();
uint64_t Addr = Sec.getAddress();
Value.Offset = RE.Addend - Addr;
}
return Value;
}
void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
const relocation_iterator &RI,
unsigned OffsetToNextPC) {
auto &O = *cast<MachOObjectFile>(RI->getObject());
section_iterator SecI = O.getRelocationRelocatedSection(RI);
Value.Offset += RI->getOffset() + OffsetToNextPC + SecI->getAddress();
}
void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
uint64_t Value) const {
const SectionEntry &Section = Sections[RE.SectionID];
uint8_t *LocalAddress = Section.getAddress() + RE.Offset;
uint64_t FinalAddress = Section.getLoadAddress() + RE.Offset;
dbgs() << "resolveRelocation Section: " << RE.SectionID
<< " LocalAddress: " << format("%p", LocalAddress)
<< " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
<< " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
<< " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
<< " Size: " << (1 << RE.Size) << "\n";
}
section_iterator
RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
uint64_t Addr) {
section_iterator SI = Obj.section_begin();
section_iterator SE = Obj.section_end();
for (; SI != SE; ++SI) {
uint64_t SAddr = SI->getAddress();
uint64_t SSize = SI->getSize();
if ((Addr >= SAddr) && (Addr < SAddr + SSize))
return SI;
}
return SE;
}
// Populate __pointers section.
Error RuntimeDyldMachO::populateIndirectSymbolPointersSection(
const MachOObjectFile &Obj,
const SectionRef &PTSection,
unsigned PTSectionID) {
assert(!Obj.is64Bit() &&
"Pointer table section not supported in 64-bit MachO.");
MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
uint32_t PTSectionSize = Sec32.size;
unsigned FirstIndirectSymbol = Sec32.reserved1;
const unsigned PTEntrySize = 4;
unsigned NumPTEntries = PTSectionSize / PTEntrySize;
unsigned PTEntryOffset = 0;
assert((PTSectionSize % PTEntrySize) == 0 &&
"Pointers section does not contain a whole number of stubs?");
DEBUG(dbgs() << "Populating pointer table section "
<< Sections[PTSectionID].getName() << ", Section ID "
<< PTSectionID << ", " << NumPTEntries << " entries, "
<< PTEntrySize << " bytes each:\n");
for (unsigned i = 0; i < NumPTEntries; ++i) {
unsigned SymbolIndex =
Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
StringRef IndirectSymbolName;
if (auto IndirectSymbolNameOrErr = SI->getName())
IndirectSymbolName = *IndirectSymbolNameOrErr;
else
return IndirectSymbolNameOrErr.takeError();
DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
<< ", PT offset: " << PTEntryOffset << "\n");
RelocationEntry RE(PTSectionID, PTEntryOffset,
MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
addRelocationForSymbol(RE, IndirectSymbolName);
PTEntryOffset += PTEntrySize;
}
return Error::success();
}
bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
return Obj.isMachO();
}
template <typename Impl>
Error
RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
ObjSectionToIDMap &SectionMap) {
unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
for (const auto &Section : Obj.sections()) {
StringRef Name;
Section.getName(Name);
// Force emission of the __text, __eh_frame, and __gcc_except_tab sections
// if they're present. Otherwise call down to the impl to handle other
// sections that have already been emitted.
if (Name == "__text") {
if (auto TextSIDOrErr = findOrEmitSection(Obj, Section, true, SectionMap))
TextSID = *TextSIDOrErr;
else
return TextSIDOrErr.takeError();
} else if (Name == "__eh_frame") {
if (auto EHFrameSIDOrErr = findOrEmitSection(Obj, Section, false,
SectionMap))
EHFrameSID = *EHFrameSIDOrErr;
else
return EHFrameSIDOrErr.takeError();
} else if (Name == "__gcc_except_tab") {
if (auto ExceptTabSIDOrErr = findOrEmitSection(Obj, Section, true,
SectionMap))
ExceptTabSID = *ExceptTabSIDOrErr;
else
return ExceptTabSIDOrErr.takeError();
} else {
auto I = SectionMap.find(Section);
if (I != SectionMap.end())
if (auto Err = impl().finalizeSection(Obj, I->second, Section))
return Err;
}
}
UnregisteredEHFrameSections.push_back(
EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
return Error::success();
}
template <typename Impl>
unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(uint8_t *P,
int64_t DeltaForText,
int64_t DeltaForEH) {
typedef typename Impl::TargetPtrT TargetPtrT;
DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
<< ", Delta for EH: " << DeltaForEH << "\n");
uint32_t Length = readBytesUnaligned(P, 4);
P += 4;
uint8_t *Ret = P + Length;
uint32_t Offset = readBytesUnaligned(P, 4);
if (Offset == 0) // is a CIE
return Ret;
P += 4;
TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
TargetPtrT NewLocation = FDELocation - DeltaForText;
writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
P += sizeof(TargetPtrT);
// Skip the FDE address range
P += sizeof(TargetPtrT);
uint8_t Augmentationsize = *P;
P += 1;
if (Augmentationsize != 0) {
TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
TargetPtrT NewLSDA = LSDA - DeltaForEH;
writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
}
return Ret;
}
static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
int64_t ObjDistance = static_cast<int64_t>(A->getObjAddress()) -
static_cast<int64_t>(B->getObjAddress());
int64_t MemDistance = A->getLoadAddress() - B->getLoadAddress();
return ObjDistance - MemDistance;
}
template <typename Impl>
void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
continue;
SectionEntry *Text = &Sections[SectionInfo.TextSID];
SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
SectionEntry *ExceptTab = nullptr;
if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
ExceptTab = &Sections[SectionInfo.ExceptTabSID];
int64_t DeltaForText = computeDelta(Text, EHFrame);
int64_t DeltaForEH = 0;
if (ExceptTab)
DeltaForEH = computeDelta(ExceptTab, EHFrame);
uint8_t *P = EHFrame->getAddress();
uint8_t *End = P + EHFrame->getSize();
while (P != End) {
P = processFDE(P, DeltaForText, DeltaForEH);
}
MemMgr.registerEHFrames(EHFrame->getAddress(), EHFrame->getLoadAddress(),
EHFrame->getSize());
}
UnregisteredEHFrameSections.clear();
}
std::unique_ptr<RuntimeDyldMachO>
RuntimeDyldMachO::create(Triple::ArchType Arch,
RuntimeDyld::MemoryManager &MemMgr,
JITSymbolResolver &Resolver) {
switch (Arch) {
default:
llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
break;
case Triple::arm:
return make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
case Triple::aarch64:
return make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
case Triple::x86:
return make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
case Triple::x86_64:
return make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
}
}
std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
return llvm::make_unique<LoadedMachOObjectInfo>(*this,
*ObjSectionToIDOrErr);
else {
HasError = true;
raw_string_ostream ErrStream(ErrorStr);
logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, "");
return nullptr;
}
}
} // end namespace llvm
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