1 //===-- RuntimeDyld.cpp - Run-time dynamic linker for MC-JIT ----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Implementation of the MC-JIT runtime dynamic linker.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/ExecutionEngine/RuntimeDyld.h"
15 #include "RuntimeDyldCheckerImpl.h"
16 #include "RuntimeDyldELF.h"
17 #include "RuntimeDyldImpl.h"
18 #include "RuntimeDyldMachO.h"
19 #include "llvm/Object/ELFObjectFile.h"
20 #include "llvm/Support/MathExtras.h"
21 #include "llvm/Support/MutexGuard.h"
24 using namespace llvm::object;
26 #define DEBUG_TYPE "dyld"
28 // Empty out-of-line virtual destructor as the key function.
29 RuntimeDyldImpl::~RuntimeDyldImpl() {}
31 // Pin LoadedObjectInfo's vtables to this file.
32 void RuntimeDyld::LoadedObjectInfo::anchor() {}
36 void RuntimeDyldImpl::registerEHFrames() {}
38 void RuntimeDyldImpl::deregisterEHFrames() {}
41 static void dumpSectionMemory(const SectionEntry &S, StringRef State) {
42 dbgs() << "----- Contents of section " << S.Name << " " << State << " -----";
44 if (S.Address == nullptr) {
45 dbgs() << "\n <section not emitted>\n";
49 const unsigned ColsPerRow = 16;
51 uint8_t *DataAddr = S.Address;
52 uint64_t LoadAddr = S.LoadAddress;
54 unsigned StartPadding = LoadAddr & (ColsPerRow - 1);
55 unsigned BytesRemaining = S.Size;
58 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr & ~(ColsPerRow - 1)) << ":";
59 while (StartPadding--)
63 while (BytesRemaining > 0) {
64 if ((LoadAddr & (ColsPerRow - 1)) == 0)
65 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr) << ":";
67 dbgs() << " " << format("%02x", *DataAddr);
78 // Resolve the relocations for all symbols we currently know about.
79 void RuntimeDyldImpl::resolveRelocations() {
80 MutexGuard locked(lock);
82 // First, resolve relocations associated with external symbols.
83 resolveExternalSymbols();
85 // Just iterate over the sections we have and resolve all the relocations
86 // in them. Gross overkill, but it gets the job done.
87 for (int i = 0, e = Sections.size(); i != e; ++i) {
88 // The Section here (Sections[i]) refers to the section in which the
89 // symbol for the relocation is located. The SectionID in the relocation
90 // entry provides the section to which the relocation will be applied.
91 uint64_t Addr = Sections[i].LoadAddress;
92 DEBUG(dbgs() << "Resolving relocations Section #" << i << "\t"
93 << format("0x%x", Addr) << "\n");
94 DEBUG(dumpSectionMemory(Sections[i], "before relocations"));
95 resolveRelocationList(Relocations[i], Addr);
96 DEBUG(dumpSectionMemory(Sections[i], "after relocations"));
101 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
102 uint64_t TargetAddress) {
103 MutexGuard locked(lock);
104 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
105 if (Sections[i].Address == LocalAddress) {
106 reassignSectionAddress(i, TargetAddress);
110 llvm_unreachable("Attempting to remap address of unknown section!");
113 static std::error_code getOffset(const SymbolRef &Sym, uint64_t &Result) {
115 if (std::error_code EC = Sym.getAddress(Address))
118 if (Address == UnknownAddressOrSize) {
119 Result = UnknownAddressOrSize;
120 return object_error::success;
123 const ObjectFile *Obj = Sym.getObject();
124 section_iterator SecI(Obj->section_begin());
125 if (std::error_code EC = Sym.getSection(SecI))
128 if (SecI == Obj->section_end()) {
129 Result = UnknownAddressOrSize;
130 return object_error::success;
133 uint64_t SectionAddress = SecI->getAddress();
134 Result = Address - SectionAddress;
135 return object_error::success;
138 std::pair<unsigned, unsigned>
139 RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
140 MutexGuard locked(lock);
142 // Grab the first Section ID. We'll use this later to construct the underlying
143 // range for the returned LoadedObjectInfo.
144 unsigned SectionsAddedBeginIdx = Sections.size();
146 // Save information about our target
147 Arch = (Triple::ArchType)Obj.getArch();
148 IsTargetLittleEndian = Obj.isLittleEndian();
150 // Compute the memory size required to load all sections to be loaded
151 // and pass this information to the memory manager
152 if (MemMgr->needsToReserveAllocationSpace()) {
153 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
154 computeTotalAllocSize(Obj, CodeSize, DataSizeRO, DataSizeRW);
155 MemMgr->reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
158 // Used sections from the object file
159 ObjSectionToIDMap LocalSections;
161 // Common symbols requiring allocation, with their sizes and alignments
162 CommonSymbolMap CommonSymbols;
163 // Maximum required total memory to allocate all common symbols
164 uint64_t CommonSize = 0;
167 DEBUG(dbgs() << "Parse symbols:\n");
168 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
170 object::SymbolRef::Type SymType;
172 Check(I->getType(SymType));
173 Check(I->getName(Name));
175 uint32_t Flags = I->getFlags();
177 bool IsCommon = Flags & SymbolRef::SF_Common;
179 // Add the common symbols to a list. We'll allocate them all below.
180 if (!GlobalSymbolTable.count(Name)) {
182 Check(I->getAlignment(Align));
184 Check(I->getSize(Size));
185 CommonSize += Size + Align;
186 CommonSymbols[*I] = CommonSymbolInfo(Size, Align);
189 if (SymType == object::SymbolRef::ST_Function ||
190 SymType == object::SymbolRef::ST_Data ||
191 SymType == object::SymbolRef::ST_Unknown) {
193 StringRef SectionData;
194 section_iterator SI = Obj.section_end();
195 Check(getOffset(*I, SectOffset));
196 Check(I->getSection(SI));
197 if (SI == Obj.section_end())
199 Check(SI->getContents(SectionData));
200 bool IsCode = SI->isText();
202 findOrEmitSection(Obj, *SI, IsCode, LocalSections);
203 DEBUG(dbgs() << "\tOffset: " << format("%p", (uintptr_t)SectOffset)
204 << " flags: " << Flags << " SID: " << SectionID);
205 GlobalSymbolTable[Name] = SymbolLoc(SectionID, SectOffset);
208 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name << "\n");
211 // Allocate common symbols
213 emitCommonSymbols(Obj, CommonSymbols, CommonSize, GlobalSymbolTable);
215 // Parse and process relocations
216 DEBUG(dbgs() << "Parse relocations:\n");
217 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
219 unsigned SectionID = 0;
221 section_iterator RelocatedSection = SI->getRelocatedSection();
223 relocation_iterator I = SI->relocation_begin();
224 relocation_iterator E = SI->relocation_end();
226 if (I == E && !ProcessAllSections)
229 bool IsCode = RelocatedSection->isText();
231 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
232 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
235 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
237 // If there is an attached checker, notify it about the stubs for this
238 // section so that they can be verified.
240 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
243 // Give the subclasses a chance to tie-up any loose ends.
244 finalizeLoad(Obj, LocalSections);
246 unsigned SectionsAddedEndIdx = Sections.size();
248 return std::make_pair(SectionsAddedBeginIdx, SectionsAddedEndIdx);
251 // A helper method for computeTotalAllocSize.
252 // Computes the memory size required to allocate sections with the given sizes,
253 // assuming that all sections are allocated with the given alignment
255 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
256 uint64_t Alignment) {
257 uint64_t TotalSize = 0;
258 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
259 uint64_t AlignedSize =
260 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
261 TotalSize += AlignedSize;
266 static bool isRequiredForExecution(const SectionRef &Section) {
267 const ObjectFile *Obj = Section.getObject();
268 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
269 return ELFObj->getSectionFlags(Section) & ELF::SHF_ALLOC;
270 assert(isa<MachOObjectFile>(Obj));
274 static bool isReadOnlyData(const SectionRef &Section) {
275 const ObjectFile *Obj = Section.getObject();
276 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
277 return !(ELFObj->getSectionFlags(Section) &
278 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
279 assert(isa<MachOObjectFile>(Obj));
283 static bool isZeroInit(const SectionRef &Section) {
284 const ObjectFile *Obj = Section.getObject();
285 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
286 return ELFObj->getSectionType(Section) == ELF::SHT_NOBITS;
288 auto *MachO = cast<MachOObjectFile>(Obj);
289 unsigned SectionType = MachO->getSectionType(Section);
290 return SectionType == MachO::S_ZEROFILL ||
291 SectionType == MachO::S_GB_ZEROFILL;
294 // Compute an upper bound of the memory size that is required to load all
296 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
298 uint64_t &DataSizeRO,
299 uint64_t &DataSizeRW) {
300 // Compute the size of all sections required for execution
301 std::vector<uint64_t> CodeSectionSizes;
302 std::vector<uint64_t> ROSectionSizes;
303 std::vector<uint64_t> RWSectionSizes;
304 uint64_t MaxAlignment = sizeof(void *);
306 // Collect sizes of all sections to be loaded;
307 // also determine the max alignment of all sections
308 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
310 const SectionRef &Section = *SI;
312 bool IsRequired = isRequiredForExecution(Section);
314 // Consider only the sections that are required to be loaded for execution
317 uint64_t DataSize = Section.getSize();
318 uint64_t Alignment64 = Section.getAlignment();
319 bool IsCode = Section.isText();
320 bool IsReadOnly = isReadOnlyData(Section);
321 Check(Section.getName(Name));
322 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
324 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
325 uint64_t SectionSize = DataSize + StubBufSize;
327 // The .eh_frame section (at least on Linux) needs an extra four bytes
329 // with zeroes added at the end. For MachO objects, this section has a
330 // slightly different name, so this won't have any effect for MachO
332 if (Name == ".eh_frame")
335 if (SectionSize > 0) {
336 // save the total size of the section
338 CodeSectionSizes.push_back(SectionSize);
339 } else if (IsReadOnly) {
340 ROSectionSizes.push_back(SectionSize);
342 RWSectionSizes.push_back(SectionSize);
344 // update the max alignment
345 if (Alignment > MaxAlignment) {
346 MaxAlignment = Alignment;
352 // Compute the size of all common symbols
353 uint64_t CommonSize = 0;
354 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
356 uint32_t Flags = I->getFlags();
357 if (Flags & SymbolRef::SF_Common) {
358 // Add the common symbols to a list. We'll allocate them all below.
360 Check(I->getSize(Size));
364 if (CommonSize != 0) {
365 RWSectionSizes.push_back(CommonSize);
368 // Compute the required allocation space for each different type of sections
369 // (code, read-only data, read-write data) assuming that all sections are
370 // allocated with the max alignment. Note that we cannot compute with the
371 // individual alignments of the sections, because then the required size
372 // depends on the order, in which the sections are allocated.
373 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
374 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
375 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
378 // compute stub buffer size for the given section
379 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
380 const SectionRef &Section) {
381 unsigned StubSize = getMaxStubSize();
385 // FIXME: this is an inefficient way to handle this. We should computed the
386 // necessary section allocation size in loadObject by walking all the sections
388 unsigned StubBufSize = 0;
389 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
391 section_iterator RelSecI = SI->getRelocatedSection();
392 if (!(RelSecI == Section))
395 for (const RelocationRef &Reloc : SI->relocations()) {
397 StubBufSize += StubSize;
401 // Get section data size and alignment
402 uint64_t DataSize = Section.getSize();
403 uint64_t Alignment64 = Section.getAlignment();
405 // Add stubbuf size alignment
406 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
407 unsigned StubAlignment = getStubAlignment();
408 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
409 if (StubAlignment > EndAlignment)
410 StubBufSize += StubAlignment - EndAlignment;
414 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
415 unsigned Size) const {
417 if (IsTargetLittleEndian) {
420 Result = (Result << 8) | *Src--;
423 Result = (Result << 8) | *Src++;
428 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
429 unsigned Size) const {
430 if (IsTargetLittleEndian) {
432 *Dst++ = Value & 0xFF;
438 *Dst-- = Value & 0xFF;
444 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
445 const CommonSymbolMap &CommonSymbols,
447 SymbolTableMap &SymbolTable) {
448 // Allocate memory for the section
449 unsigned SectionID = Sections.size();
450 uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, sizeof(void *),
451 SectionID, StringRef(), false);
453 report_fatal_error("Unable to allocate memory for common symbols!");
455 Sections.push_back(SectionEntry("<common symbols>", Addr, TotalSize, 0));
456 memset(Addr, 0, TotalSize);
458 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
459 << format("%p", Addr) << " DataSize: " << TotalSize << "\n");
461 // Assign the address of each symbol
462 for (CommonSymbolMap::const_iterator it = CommonSymbols.begin(),
463 itEnd = CommonSymbols.end(); it != itEnd; ++it) {
464 uint64_t Size = it->second.first;
465 uint64_t Align = it->second.second;
467 it->first.getName(Name);
469 // This symbol has an alignment requirement.
470 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
472 Offset += AlignOffset;
473 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
474 << format("%p\n", Addr));
476 SymbolTable[Name.data()] = SymbolLoc(SectionID, Offset);
482 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
483 const SectionRef &Section, bool IsCode) {
486 Check(Section.getContents(data));
487 uint64_t Alignment64 = Section.getAlignment();
489 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
490 unsigned PaddingSize = 0;
491 unsigned StubBufSize = 0;
493 bool IsRequired = isRequiredForExecution(Section);
494 bool IsVirtual = Section.isVirtual();
495 bool IsZeroInit = isZeroInit(Section);
496 bool IsReadOnly = isReadOnlyData(Section);
497 uint64_t DataSize = Section.getSize();
498 Check(Section.getName(Name));
500 StubBufSize = computeSectionStubBufSize(Obj, Section);
502 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
503 // with zeroes added at the end. For MachO objects, this section has a
504 // slightly different name, so this won't have any effect for MachO objects.
505 if (Name == ".eh_frame")
509 unsigned SectionID = Sections.size();
511 const char *pData = nullptr;
513 // Some sections, such as debug info, don't need to be loaded for execution.
514 // Leave those where they are.
516 Allocate = DataSize + PaddingSize + StubBufSize;
517 Addr = IsCode ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID,
519 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID,
522 report_fatal_error("Unable to allocate section memory!");
524 // Virtual sections have no data in the object image, so leave pData = 0
528 // Zero-initialize or copy the data from the image
529 if (IsZeroInit || IsVirtual)
530 memset(Addr, 0, DataSize);
532 memcpy(Addr, pData, DataSize);
534 // Fill in any extra bytes we allocated for padding
535 if (PaddingSize != 0) {
536 memset(Addr + DataSize, 0, PaddingSize);
537 // Update the DataSize variable so that the stub offset is set correctly.
538 DataSize += PaddingSize;
541 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
542 << " obj addr: " << format("%p", pData)
543 << " new addr: " << format("%p", Addr)
544 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
545 << " Allocate: " << Allocate << "\n");
547 // Even if we didn't load the section, we need to record an entry for it
548 // to handle later processing (and by 'handle' I mean don't do anything
549 // with these sections).
552 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
553 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
554 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
555 << " Allocate: " << Allocate << "\n");
558 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
561 Checker->registerSection(Obj.getFileName(), SectionID);
566 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
567 const SectionRef &Section,
569 ObjSectionToIDMap &LocalSections) {
571 unsigned SectionID = 0;
572 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
573 if (i != LocalSections.end())
574 SectionID = i->second;
576 SectionID = emitSection(Obj, Section, IsCode);
577 LocalSections[Section] = SectionID;
582 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
583 unsigned SectionID) {
584 Relocations[SectionID].push_back(RE);
587 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
588 StringRef SymbolName) {
589 // Relocation by symbol. If the symbol is found in the global symbol table,
590 // create an appropriate section relocation. Otherwise, add it to
591 // ExternalSymbolRelocations.
592 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
593 if (Loc == GlobalSymbolTable.end()) {
594 ExternalSymbolRelocations[SymbolName].push_back(RE);
596 // Copy the RE since we want to modify its addend.
597 RelocationEntry RECopy = RE;
598 RECopy.Addend += Loc->second.second;
599 Relocations[Loc->second.first].push_back(RECopy);
603 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
604 unsigned AbiVariant) {
605 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
606 // This stub has to be able to access the full address space,
607 // since symbol lookup won't necessarily find a handy, in-range,
608 // PLT stub for functions which could be anywhere.
609 // Stub can use ip0 (== x16) to calculate address
610 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
611 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
612 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
613 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
614 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
617 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
618 // TODO: There is only ARM far stub now. We should add the Thumb stub,
619 // and stubs for branches Thumb - ARM and ARM - Thumb.
620 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
622 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
623 // 0: 3c190000 lui t9,%hi(addr).
624 // 4: 27390000 addiu t9,t9,%lo(addr).
625 // 8: 03200008 jr t9.
627 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
628 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
630 writeBytesUnaligned(LuiT9Instr, Addr, 4);
631 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
632 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
633 writeBytesUnaligned(NopInstr, Addr+12, 4);
635 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
636 // Depending on which version of the ELF ABI is in use, we need to
637 // generate one of two variants of the stub. They both start with
638 // the same sequence to load the target address into r12.
639 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
640 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
641 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
642 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
643 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
644 if (AbiVariant == 2) {
645 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
646 // The address is already in r12 as required by the ABI. Branch to it.
647 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
648 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
649 writeInt32BE(Addr+28, 0x4E800420); // bctr
651 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
652 // Load the function address on r11 and sets it to control register. Also
653 // loads the function TOC in r2 and environment pointer to r11.
654 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
655 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
656 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
657 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
658 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
659 writeInt32BE(Addr+40, 0x4E800420); // bctr
662 } else if (Arch == Triple::systemz) {
663 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
664 writeInt16BE(Addr+2, 0x0000);
665 writeInt16BE(Addr+4, 0x0004);
666 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
667 // 8-byte address stored at Addr + 8
669 } else if (Arch == Triple::x86_64) {
671 *(Addr+1) = 0x25; // rip
672 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
673 } else if (Arch == Triple::x86) {
674 *Addr = 0xE9; // 32-bit pc-relative jump.
679 // Assign an address to a symbol name and resolve all the relocations
680 // associated with it.
681 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
683 // The address to use for relocation resolution is not
684 // the address of the local section buffer. We must be doing
685 // a remote execution environment of some sort. Relocations can't
686 // be applied until all the sections have been moved. The client must
687 // trigger this with a call to MCJIT::finalize() or
688 // RuntimeDyld::resolveRelocations().
690 // Addr is a uint64_t because we can't assume the pointer width
691 // of the target is the same as that of the host. Just use a generic
692 // "big enough" type.
693 DEBUG(dbgs() << "Reassigning address for section "
694 << SectionID << " (" << Sections[SectionID].Name << "): "
695 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
696 << format("0x%016" PRIx64, Addr) << "\n");
697 Sections[SectionID].LoadAddress = Addr;
700 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
702 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
703 const RelocationEntry &RE = Relocs[i];
704 // Ignore relocations for sections that were not loaded
705 if (Sections[RE.SectionID].Address == nullptr)
707 resolveRelocation(RE, Value);
711 void RuntimeDyldImpl::resolveExternalSymbols() {
712 while (!ExternalSymbolRelocations.empty()) {
713 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
715 StringRef Name = i->first();
716 if (Name.size() == 0) {
717 // This is an absolute symbol, use an address of zero.
718 DEBUG(dbgs() << "Resolving absolute relocations."
720 RelocationList &Relocs = i->second;
721 resolveRelocationList(Relocs, 0);
724 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(Name);
725 if (Loc == GlobalSymbolTable.end()) {
726 // This is an external symbol, try to get its address from
728 Addr = MemMgr->getSymbolAddress(Name.data());
729 // The call to getSymbolAddress may have caused additional modules to
730 // be loaded, which may have added new entries to the
731 // ExternalSymbolRelocations map. Consquently, we need to update our
732 // iterator. This is also why retrieval of the relocation list
733 // associated with this symbol is deferred until below this point.
734 // New entries may have been added to the relocation list.
735 i = ExternalSymbolRelocations.find(Name);
737 // We found the symbol in our global table. It was probably in a
738 // Module that we loaded previously.
739 SymbolLoc SymLoc = Loc->second;
740 Addr = getSectionLoadAddress(SymLoc.first) + SymLoc.second;
743 // FIXME: Implement error handling that doesn't kill the host program!
745 report_fatal_error("Program used external function '" + Name +
746 "' which could not be resolved!");
748 updateGOTEntries(Name, Addr);
749 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
750 << format("0x%lx", Addr) << "\n");
751 // This list may have been updated when we called getSymbolAddress, so
752 // don't change this code to get the list earlier.
753 RelocationList &Relocs = i->second;
754 resolveRelocationList(Relocs, Addr);
757 ExternalSymbolRelocations.erase(i);
761 //===----------------------------------------------------------------------===//
762 // RuntimeDyld class implementation
764 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
765 StringRef SectionName) const {
766 for (unsigned I = BeginIdx; I != EndIdx; ++I)
767 if (RTDyld.Sections[I].Name == SectionName)
768 return RTDyld.Sections[I].LoadAddress;
773 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
774 // FIXME: There's a potential issue lurking here if a single instance of
775 // RuntimeDyld is used to load multiple objects. The current implementation
776 // associates a single memory manager with a RuntimeDyld instance. Even
777 // though the public class spawns a new 'impl' instance for each load,
778 // they share a single memory manager. This can become a problem when page
779 // permissions are applied.
782 ProcessAllSections = false;
786 RuntimeDyld::~RuntimeDyld() {}
788 static std::unique_ptr<RuntimeDyldELF>
789 createRuntimeDyldELF(RTDyldMemoryManager *MM, bool ProcessAllSections,
790 RuntimeDyldCheckerImpl *Checker) {
791 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM));
792 Dyld->setProcessAllSections(ProcessAllSections);
793 Dyld->setRuntimeDyldChecker(Checker);
797 static std::unique_ptr<RuntimeDyldMachO>
798 createRuntimeDyldMachO(Triple::ArchType Arch, RTDyldMemoryManager *MM,
799 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
800 std::unique_ptr<RuntimeDyldMachO> Dyld(RuntimeDyldMachO::create(Arch, MM));
801 Dyld->setProcessAllSections(ProcessAllSections);
802 Dyld->setRuntimeDyldChecker(Checker);
806 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
807 RuntimeDyld::loadObject(const ObjectFile &Obj) {
810 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
811 else if (Obj.isMachO())
812 Dyld = createRuntimeDyldMachO(
813 static_cast<Triple::ArchType>(Obj.getArch()), MM,
814 ProcessAllSections, Checker);
816 report_fatal_error("Incompatible object format!");
819 if (!Dyld->isCompatibleFile(Obj))
820 report_fatal_error("Incompatible object format!");
822 return Dyld->loadObject(Obj);
825 void *RuntimeDyld::getSymbolAddress(StringRef Name) const {
828 return Dyld->getSymbolAddress(Name);
831 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) const {
834 return Dyld->getSymbolLoadAddress(Name);
837 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
839 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
840 Dyld->reassignSectionAddress(SectionID, Addr);
843 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
844 uint64_t TargetAddress) {
845 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
848 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
850 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
852 void RuntimeDyld::registerEHFrames() {
854 Dyld->registerEHFrames();
857 void RuntimeDyld::deregisterEHFrames() {
859 Dyld->deregisterEHFrames();
862 } // end namespace llvm