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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 "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "Targets/RuntimeDyldMachOARM.h"
#include "Targets/RuntimeDyldMachOAArch64.h"
#include "Targets/RuntimeDyldMachOI386.h"
#include "Targets/RuntimeDyldMachOX86_64.h"
using namespace llvm;
using namespace llvm::object;
#define DEBUG_TYPE "dyld"
namespace llvm {
int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
unsigned NumBytes = 1 << RE.Size;
uint8_t *Src = Sections[RE.SectionID].Address + RE.Offset;
return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
}
RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
ObjectImage &ObjImg, const relocation_iterator &RI,
const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID,
const SymbolTableMap &Symbols) {
const MachOObjectFile &Obj =
static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
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 = Symbols.find(TargetName.data());
if (SI != Symbols.end()) {
Value.SectionID = SI->second.first;
Value.Offset = SI->second.second + RE.Addend;
} else {
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(ObjImg, Sec, IsCode, ObjSectionToID);
uint64_t Addr = Sec.getAddress();
Value.Offset = RE.Addend - Addr;
}
return Value;
}
void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
ObjectImage &ObjImg,
const relocation_iterator &RI,
unsigned OffsetToNextPC) {
const MachOObjectFile &Obj =
static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
MachO::any_relocation_info RelInfo =
Obj.getRelocation(RI->getRawDataRefImpl());
bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
if (IsPCRel) {
uint64_t RelocAddr = 0;
RI->getAddress(RelocAddr);
Value.Offset += RelocAddr + OffsetToNextPC;
}
}
void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
uint64_t Value) const {
const SectionEntry &Section = Sections[RE.SectionID];
uint8_t *LocalAddress = Section.Address + RE.Offset;
uint64_t FinalAddress = Section.LoadAddress + 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.
void RuntimeDyldMachO::populateIndirectSymbolPointersSection(
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].Name
<< ", 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;
SI->getName(IndirectSymbolName);
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;
}
}
bool
RuntimeDyldMachO::isCompatibleFormat(const ObjectBuffer *InputBuffer) const {
if (InputBuffer->getBufferSize() < 4)
return false;
StringRef Magic(InputBuffer->getBufferStart(), 4);
if (Magic == "\xFE\xED\xFA\xCE")
return true;
if (Magic == "\xCE\xFA\xED\xFE")
return true;
if (Magic == "\xFE\xED\xFA\xCF")
return true;
if (Magic == "\xCF\xFA\xED\xFE")
return true;
return false;
}
bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile *Obj) const {
return Obj->isMachO();
}
template <typename Impl>
void RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(ObjectImage &ObjImg,
ObjSectionToIDMap &SectionMap) {
unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
ObjSectionToIDMap::iterator i, e;
for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
const SectionRef &Section = i->first;
StringRef Name;
Section.getName(Name);
if (Name == "__eh_frame")
EHFrameSID = i->second;
else if (Name == "__text")
TextSID = i->second;
else if (Name == "__gcc_except_tab")
ExceptTabSID = i->second;
else
impl().finalizeSection(ObjImg, i->second, Section);
}
UnregisteredEHFrameSections.push_back(
EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
}
template <typename Impl>
unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(unsigned char *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;
unsigned char *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 = A->ObjAddress - B->ObjAddress;
int64_t MemDistance = A->LoadAddress - B->LoadAddress;
return ObjDistance - MemDistance;
}
template <typename Impl>
void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
if (!MemMgr)
return;
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);
unsigned char *P = EHFrame->Address;
unsigned char *End = P + EHFrame->Size;
do {
P = processFDE(P, DeltaForText, DeltaForEH);
} while (P != End);
MemMgr->registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
EHFrame->Size);
}
UnregisteredEHFrameSections.clear();
}
std::unique_ptr<RuntimeDyldMachO>
llvm::RuntimeDyldMachO::create(Triple::ArchType Arch, RTDyldMemoryManager *MM) {
switch (Arch) {
default:
llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
break;
case Triple::arm: return make_unique<RuntimeDyldMachOARM>(MM);
case Triple::aarch64: return make_unique<RuntimeDyldMachOAArch64>(MM);
case Triple::x86: return make_unique<RuntimeDyldMachOI386>(MM);
case Triple::x86_64: return make_unique<RuntimeDyldMachOX86_64>(MM);
}
}
} // end namespace llvm
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