//===-- RuntimeDyld.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.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "dyld"
#include "RuntimeDyldImpl.h"
#include "RuntimeDyldELF.h"
#include "RuntimeDyldMachO.h"
#include "llvm/Support/Path.h"
using namespace llvm;
using namespace llvm::object;
// Empty out-of-line virtual destructor as the key function.
RTDyldMemoryManager::~RTDyldMemoryManager() {}
RuntimeDyldImpl::~RuntimeDyldImpl() {}
namespace llvm {
namespace {
// Helper for extensive error checking in debug builds.
error_code Check(error_code Err) {
if (Err) {
report_fatal_error(Err.message());
}
return Err;
}
} // end anonymous namespace
// Resolve the relocations for all symbols we currently know about.
void RuntimeDyldImpl::resolveRelocations() {
// First, resolve relocations associated with external symbols.
resolveSymbols();
// Just iterate over the sections we have and resolve all the relocations
// in them. Gross overkill, but it gets the job done.
for (int i = 0, e = Sections.size(); i != e; ++i) {
reassignSectionAddress(i, Sections[i].LoadAddress);
}
}
void RuntimeDyldImpl::mapSectionAddress(void *LocalAddress,
uint64_t TargetAddress) {
for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
if (Sections[i].Address == LocalAddress) {
reassignSectionAddress(i, TargetAddress);
return;
}
}
llvm_unreachable("Attempting to remap address of unknown section!");
}
// Subclasses can implement this method to create specialized image instances
// The caller owns the the pointer that is returned.
ObjectImage *RuntimeDyldImpl::createObjectImage(const MemoryBuffer *InputBuffer) {
ObjectFile *ObjFile = ObjectFile::createObjectFile(const_cast<MemoryBuffer*>
(InputBuffer));
ObjectImage *Obj = new ObjectImage(ObjFile);
return Obj;
}
bool RuntimeDyldImpl::loadObject(const MemoryBuffer *InputBuffer) {
OwningPtr<ObjectImage> obj(createObjectImage(InputBuffer));
if (!obj)
report_fatal_error("Unable to create object image from memory buffer!");
Arch = (Triple::ArchType)obj->getArch();
LocalSymbolMap LocalSymbols; // Functions and data symbols from the
// object file.
ObjSectionToIDMap LocalSections; // Used sections from the object file
CommonSymbolMap CommonSymbols; // Common symbols requiring allocation
uint64_t CommonSize = 0;
error_code err;
// Parse symbols
DEBUG(dbgs() << "Parse symbols:\n");
for (symbol_iterator i = obj->begin_symbols(), e = obj->end_symbols();
i != e; i.increment(err)) {
Check(err);
object::SymbolRef::Type SymType;
StringRef Name;
Check(i->getType(SymType));
Check(i->getName(Name));
uint32_t flags;
Check(i->getFlags(flags));
bool isCommon = flags & SymbolRef::SF_Common;
if (isCommon) {
// Add the common symbols to a list. We'll allocate them all below.
uint64_t Size = 0;
Check(i->getSize(Size));
CommonSize += Size;
CommonSymbols[*i] = Size;
} else {
if (SymType == object::SymbolRef::ST_Function ||
SymType == object::SymbolRef::ST_Data) {
uint64_t FileOffset;
StringRef sData;
section_iterator si = obj->end_sections();
Check(i->getFileOffset(FileOffset));
Check(i->getSection(si));
if (si == obj->end_sections()) continue;
Check(si->getContents(sData));
const uint8_t* SymPtr = (const uint8_t*)InputBuffer->getBufferStart() +
(uintptr_t)FileOffset;
uintptr_t SectOffset = (uintptr_t)(SymPtr - (const uint8_t*)sData.begin());
unsigned SectionID =
findOrEmitSection(*obj,
*si,
SymType == object::SymbolRef::ST_Function,
LocalSections);
bool isGlobal = flags & SymbolRef::SF_Global;
LocalSymbols[Name.data()] = SymbolLoc(SectionID, SectOffset);
DEBUG(dbgs() << "\tFileOffset: " << format("%p", (uintptr_t)FileOffset)
<< " flags: " << flags
<< " SID: " << SectionID
<< " Offset: " << format("%p", SectOffset));
if (isGlobal)
SymbolTable[Name] = SymbolLoc(SectionID, SectOffset);
}
}
DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name << "\n");
}
// Allocate common symbols
if (CommonSize != 0)
emitCommonSymbols(*obj, CommonSymbols, CommonSize, LocalSymbols);
// Parse and proccess relocations
DEBUG(dbgs() << "Parse relocations:\n");
for (section_iterator si = obj->begin_sections(),
se = obj->end_sections(); si != se; si.increment(err)) {
Check(err);
bool isFirstRelocation = true;
unsigned SectionID = 0;
StubMap Stubs;
for (relocation_iterator i = si->begin_relocations(),
e = si->end_relocations(); i != e; i.increment(err)) {
Check(err);
// If it's first relocation in this section, find its SectionID
if (isFirstRelocation) {
SectionID = findOrEmitSection(*obj, *si, true, LocalSections);
DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
isFirstRelocation = false;
}
ObjRelocationInfo RI;
RI.SectionID = SectionID;
Check(i->getAdditionalInfo(RI.AdditionalInfo));
Check(i->getOffset(RI.Offset));
Check(i->getSymbol(RI.Symbol));
Check(i->getType(RI.Type));
DEBUG(dbgs() << "\t\tAddend: " << RI.AdditionalInfo
<< " Offset: " << format("%p", (uintptr_t)RI.Offset)
<< " Type: " << (uint32_t)(RI.Type & 0xffffffffL)
<< "\n");
processRelocationRef(RI, *obj, LocalSections, LocalSymbols, Stubs);
}
}
handleObjectLoaded(obj.take());
return false;
}
unsigned RuntimeDyldImpl::emitCommonSymbols(ObjectImage &Obj,
const CommonSymbolMap &Map,
uint64_t TotalSize,
LocalSymbolMap &LocalSymbols) {
// Allocate memory for the section
unsigned SectionID = Sections.size();
uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, sizeof(void*),
SectionID);
if (!Addr)
report_fatal_error("Unable to allocate memory for common symbols!");
uint64_t Offset = 0;
Sections.push_back(SectionEntry(Addr, TotalSize, TotalSize, 0));
memset(Addr, 0, TotalSize);
DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID
<< " new addr: " << format("%p", Addr)
<< " DataSize: " << TotalSize
<< "\n");
// Assign the address of each symbol
for (CommonSymbolMap::const_iterator it = Map.begin(), itEnd = Map.end();
it != itEnd; it++) {
uint64_t Size = it->second;
StringRef Name;
it->first.getName(Name);
Obj.updateSymbolAddress(it->first, (uint64_t)Addr);
LocalSymbols[Name.data()] = SymbolLoc(SectionID, Offset);
Offset += Size;
Addr += Size;
}
return SectionID;
}
unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
const SectionRef &Section,
bool IsCode) {
unsigned StubBufSize = 0,
StubSize = getMaxStubSize();
error_code err;
if (StubSize > 0) {
for (relocation_iterator i = Section.begin_relocations(),
e = Section.end_relocations(); i != e; i.increment(err), Check(err))
StubBufSize += StubSize;
}
StringRef data;
uint64_t Alignment64;
Check(Section.getContents(data));
Check(Section.getAlignment(Alignment64));
unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
bool IsRequired;
bool IsVirtual;
bool IsZeroInit;
uint64_t DataSize;
Check(Section.isRequiredForExecution(IsRequired));
Check(Section.isVirtual(IsVirtual));
Check(Section.isZeroInit(IsZeroInit));
Check(Section.getSize(DataSize));
unsigned Allocate;
unsigned SectionID = Sections.size();
uint8_t *Addr;
const char *pData = 0;
// Some sections, such as debug info, don't need to be loaded for execution.
// Leave those where they are.
if (IsRequired) {
Allocate = DataSize + StubBufSize;
Addr = IsCode
? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID)
: MemMgr->allocateDataSection(Allocate, Alignment, SectionID);
if (!Addr)
report_fatal_error("Unable to allocate section memory!");
// Virtual sections have no data in the object image, so leave pData = 0
if (!IsVirtual)
pData = data.data();
// Zero-initialize or copy the data from the image
if (IsZeroInit || IsVirtual)
memset(Addr, 0, DataSize);
else
memcpy(Addr, pData, DataSize);
DEBUG(dbgs() << "emitSection SectionID: " << SectionID
<< " obj addr: " << format("%p", pData)
<< " new addr: " << format("%p", Addr)
<< " DataSize: " << DataSize
<< " StubBufSize: " << StubBufSize
<< " Allocate: " << Allocate
<< "\n");
Obj.updateSectionAddress(Section, (uint64_t)Addr);
}
else {
// Even if we didn't load the section, we need to record an entry for it
// to handle later processing (and by 'handle' I mean don't do anything
// with these sections).
Allocate = 0;
Addr = 0;
DEBUG(dbgs() << "emitSection SectionID: " << SectionID
<< " obj addr: " << format("%p", data.data())
<< " new addr: 0"
<< " DataSize: " << DataSize
<< " StubBufSize: " << StubBufSize
<< " Allocate: " << Allocate
<< "\n");
}
Sections.push_back(SectionEntry(Addr, Allocate, DataSize,(uintptr_t)pData));
return SectionID;
}
unsigned RuntimeDyldImpl::findOrEmitSection(ObjectImage &Obj,
const SectionRef &Section,
bool IsCode,
ObjSectionToIDMap &LocalSections) {
unsigned SectionID = 0;
ObjSectionToIDMap::iterator i = LocalSections.find(Section);
if (i != LocalSections.end())
SectionID = i->second;
else {
SectionID = emitSection(Obj, Section, IsCode);
LocalSections[Section] = SectionID;
}
return SectionID;
}
void RuntimeDyldImpl::AddRelocation(const RelocationValueRef &Value,
unsigned SectionID, uintptr_t Offset,
uint32_t RelType) {
DEBUG(dbgs() << "AddRelocation SymNamePtr: " << format("%p", Value.SymbolName)
<< " SID: " << Value.SectionID
<< " Addend: " << format("%p", Value.Addend)
<< " Offset: " << format("%p", Offset)
<< " RelType: " << format("%x", RelType)
<< "\n");
if (Value.SymbolName == 0) {
Relocations[Value.SectionID].push_back(RelocationEntry(
SectionID,
Offset,
RelType,
Value.Addend));
} else
SymbolRelocations[Value.SymbolName].push_back(RelocationEntry(
SectionID,
Offset,
RelType,
Value.Addend));
}
uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr) {
// TODO: There is only ARM far stub now. We should add the Thumb stub,
// and stubs for branches Thumb - ARM and ARM - Thumb.
if (Arch == Triple::arm) {
uint32_t *StubAddr = (uint32_t*)Addr;
*StubAddr = 0xe51ff004; // ldr pc,<label>
return (uint8_t*)++StubAddr;
}
else
return Addr;
}
// Assign an address to a symbol name and resolve all the relocations
// associated with it.
void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
uint64_t Addr) {
// The address to use for relocation resolution is not
// the address of the local section buffer. We must be doing
// a remote execution environment of some sort. Re-apply any
// relocations referencing this section with the given address.
//
// Addr is a uint64_t because we can't assume the pointer width
// of the target is the same as that of the host. Just use a generic
// "big enough" type.
Sections[SectionID].LoadAddress = Addr;
DEBUG(dbgs() << "Resolving relocations Section #" << SectionID
<< "\t" << format("%p", (uint8_t *)Addr)
<< "\n");
resolveRelocationList(Relocations[SectionID], Addr);
}
void RuntimeDyldImpl::resolveRelocationEntry(const RelocationEntry &RE,
uint64_t Value) {
// Ignore relocations for sections that were not loaded
if (Sections[RE.SectionID].Address != 0) {
uint8_t *Target = Sections[RE.SectionID].Address + RE.Offset;
DEBUG(dbgs() << "\tSectionID: " << RE.SectionID
<< " + " << RE.Offset << " (" << format("%p", Target) << ")"
<< " Data: " << RE.Data
<< " Addend: " << RE.Addend
<< "\n");
resolveRelocation(Target, Sections[RE.SectionID].LoadAddress + RE.Offset,
Value, RE.Data, RE.Addend);
}
}
void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
uint64_t Value) {
for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
resolveRelocationEntry(Relocs[i], Value);
}
}
// resolveSymbols - Resolve any relocations to the specified symbols if
// we know where it lives.
void RuntimeDyldImpl::resolveSymbols() {
StringMap<RelocationList>::iterator i = SymbolRelocations.begin(),
e = SymbolRelocations.end();
for (; i != e; i++) {
StringRef Name = i->first();
RelocationList &Relocs = i->second;
StringMap<SymbolLoc>::const_iterator Loc = SymbolTable.find(Name);
if (Loc == SymbolTable.end()) {
// This is an external symbol, try to get it address from
// MemoryManager.
uint8_t *Addr = (uint8_t*) MemMgr->getPointerToNamedFunction(Name.data(),
true);
DEBUG(dbgs() << "Resolving relocations Name: " << Name
<< "\t" << format("%p", Addr)
<< "\n");
resolveRelocationList(Relocs, (uintptr_t)Addr);
} else {
// Change the relocation to be section relative rather than symbol
// relative and move it to the resolved relocation list.
DEBUG(dbgs() << "Resolving symbol '" << Name << "'\n");
for (int i = 0, e = Relocs.size(); i != e; ++i) {
RelocationEntry Entry = Relocs[i];
Entry.Addend += Loc->second.second;
Relocations[Loc->second.first].push_back(Entry);
}
Relocs.clear();
}
}
}
//===----------------------------------------------------------------------===//
// RuntimeDyld class implementation
RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
Dyld = 0;
MM = mm;
}
RuntimeDyld::~RuntimeDyld() {
delete Dyld;
}
bool RuntimeDyld::loadObject(MemoryBuffer *InputBuffer) {
if (!Dyld) {
sys::LLVMFileType type = sys::IdentifyFileType(
InputBuffer->getBufferStart(),
static_cast<unsigned>(InputBuffer->getBufferSize()));
switch (type) {
case sys::ELF_Relocatable_FileType:
case sys::ELF_Executable_FileType:
case sys::ELF_SharedObject_FileType:
case sys::ELF_Core_FileType:
Dyld = new RuntimeDyldELF(MM);
break;
case sys::Mach_O_Object_FileType:
case sys::Mach_O_Executable_FileType:
case sys::Mach_O_FixedVirtualMemorySharedLib_FileType:
case sys::Mach_O_Core_FileType:
case sys::Mach_O_PreloadExecutable_FileType:
case sys::Mach_O_DynamicallyLinkedSharedLib_FileType:
case sys::Mach_O_DynamicLinker_FileType:
case sys::Mach_O_Bundle_FileType:
case sys::Mach_O_DynamicallyLinkedSharedLibStub_FileType:
case sys::Mach_O_DSYMCompanion_FileType:
Dyld = new RuntimeDyldMachO(MM);
break;
case sys::Unknown_FileType:
case sys::Bitcode_FileType:
case sys::Archive_FileType:
case sys::COFF_FileType:
report_fatal_error("Incompatible object format!");
}
} else {
if (!Dyld->isCompatibleFormat(InputBuffer))
report_fatal_error("Incompatible object format!");
}
return Dyld->loadObject(InputBuffer);
}
void *RuntimeDyld::getSymbolAddress(StringRef Name) {
return Dyld->getSymbolAddress(Name);
}
void RuntimeDyld::resolveRelocations() {
Dyld->resolveRelocations();
}
void RuntimeDyld::reassignSectionAddress(unsigned SectionID,
uint64_t Addr) {
Dyld->reassignSectionAddress(SectionID, Addr);
}
void RuntimeDyld::mapSectionAddress(void *LocalAddress,
uint64_t TargetAddress) {
Dyld->mapSectionAddress(LocalAddress, TargetAddress);
}
StringRef RuntimeDyld::getErrorString() {
return Dyld->getErrorString();
}
} // end namespace llvm