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 CommonSymbolList CommonSymbols;
165 DEBUG(dbgs() << "Parse symbols:\n");
166 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
168 uint32_t Flags = I->getFlags();
170 bool IsCommon = Flags & SymbolRef::SF_Common;
171 bool IsWeak = Flags & SymbolRef::SF_Weak;
173 CommonSymbols.push_back(*I);
175 object::SymbolRef::Type SymType;
176 Check(I->getType(SymType));
178 if (SymType == object::SymbolRef::ST_Function ||
179 SymType == object::SymbolRef::ST_Data ||
180 SymType == object::SymbolRef::ST_Unknown) {
184 Check(I->getName(Name));
185 Check(getOffset(*I, SectOffset));
186 section_iterator SI = Obj.section_end();
187 Check(I->getSection(SI));
188 if (SI == Obj.section_end())
190 StringRef SectionData;
191 Check(SI->getContents(SectionData));
192 // TODO: It make make sense to delay emitting the section for weak
193 // symbols until they are actually required, but that's not possible
194 // currently, because we only know whether we will need the symbol
195 // in resolveRelocations, which happens after we have already finalized
197 bool IsCode = SI->isText();
199 findOrEmitSection(Obj, *SI, IsCode, LocalSections);
200 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
201 << " SID: " << SectionID << " Offset: "
202 << format("%p", (uintptr_t)SectOffset)
203 << " flags: " << Flags << "\n");
204 SymbolInfo::Visibility Vis =
205 (Flags & SymbolRef::SF_Exported) ?
206 SymbolInfo::Default : SymbolInfo::Hidden;
208 GlobalSymbolTable[Name] = SymbolInfo(SectionID, SectOffset, Vis);
210 WeakSymbolTable[Name] = SymbolInfo(SectionID, SectOffset, Vis);
216 // Allocate common symbols
217 emitCommonSymbols(Obj, CommonSymbols);
219 // Parse and process relocations
220 DEBUG(dbgs() << "Parse relocations:\n");
221 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
223 unsigned SectionID = 0;
225 section_iterator RelocatedSection = SI->getRelocatedSection();
227 relocation_iterator I = SI->relocation_begin();
228 relocation_iterator E = SI->relocation_end();
230 if (I == E && !ProcessAllSections)
233 bool IsCode = RelocatedSection->isText();
235 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
236 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
239 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
241 // If there is an attached checker, notify it about the stubs for this
242 // section so that they can be verified.
244 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
247 // Give the subclasses a chance to tie-up any loose ends.
248 finalizeLoad(Obj, LocalSections);
250 unsigned SectionsAddedEndIdx = Sections.size();
252 return std::make_pair(SectionsAddedBeginIdx, SectionsAddedEndIdx);
255 // A helper method for computeTotalAllocSize.
256 // Computes the memory size required to allocate sections with the given sizes,
257 // assuming that all sections are allocated with the given alignment
259 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
260 uint64_t Alignment) {
261 uint64_t TotalSize = 0;
262 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
263 uint64_t AlignedSize =
264 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
265 TotalSize += AlignedSize;
270 static bool isRequiredForExecution(const SectionRef &Section) {
271 const ObjectFile *Obj = Section.getObject();
272 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
273 return ELFObj->getSectionFlags(Section) & ELF::SHF_ALLOC;
274 assert(isa<MachOObjectFile>(Obj));
278 static bool isReadOnlyData(const SectionRef &Section) {
279 const ObjectFile *Obj = Section.getObject();
280 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
281 return !(ELFObj->getSectionFlags(Section) &
282 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
283 assert(isa<MachOObjectFile>(Obj));
287 static bool isZeroInit(const SectionRef &Section) {
288 const ObjectFile *Obj = Section.getObject();
289 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
290 return ELFObj->getSectionType(Section) == ELF::SHT_NOBITS;
292 auto *MachO = cast<MachOObjectFile>(Obj);
293 unsigned SectionType = MachO->getSectionType(Section);
294 return SectionType == MachO::S_ZEROFILL ||
295 SectionType == MachO::S_GB_ZEROFILL;
298 // Compute an upper bound of the memory size that is required to load all
300 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
302 uint64_t &DataSizeRO,
303 uint64_t &DataSizeRW) {
304 // Compute the size of all sections required for execution
305 std::vector<uint64_t> CodeSectionSizes;
306 std::vector<uint64_t> ROSectionSizes;
307 std::vector<uint64_t> RWSectionSizes;
308 uint64_t MaxAlignment = sizeof(void *);
310 // Collect sizes of all sections to be loaded;
311 // also determine the max alignment of all sections
312 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
314 const SectionRef &Section = *SI;
316 bool IsRequired = isRequiredForExecution(Section);
318 // Consider only the sections that are required to be loaded for execution
321 uint64_t DataSize = Section.getSize();
322 uint64_t Alignment64 = Section.getAlignment();
323 bool IsCode = Section.isText();
324 bool IsReadOnly = isReadOnlyData(Section);
325 Check(Section.getName(Name));
326 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
328 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
329 uint64_t SectionSize = DataSize + StubBufSize;
331 // The .eh_frame section (at least on Linux) needs an extra four bytes
333 // with zeroes added at the end. For MachO objects, this section has a
334 // slightly different name, so this won't have any effect for MachO
336 if (Name == ".eh_frame")
339 if (SectionSize > 0) {
340 // save the total size of the section
342 CodeSectionSizes.push_back(SectionSize);
343 } else if (IsReadOnly) {
344 ROSectionSizes.push_back(SectionSize);
346 RWSectionSizes.push_back(SectionSize);
348 // update the max alignment
349 if (Alignment > MaxAlignment) {
350 MaxAlignment = Alignment;
356 // Compute the size of all common symbols
357 uint64_t CommonSize = 0;
358 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
360 uint32_t Flags = I->getFlags();
361 if (Flags & SymbolRef::SF_Common) {
362 // Add the common symbols to a list. We'll allocate them all below.
364 Check(I->getSize(Size));
368 if (CommonSize != 0) {
369 RWSectionSizes.push_back(CommonSize);
372 // Compute the required allocation space for each different type of sections
373 // (code, read-only data, read-write data) assuming that all sections are
374 // allocated with the max alignment. Note that we cannot compute with the
375 // individual alignments of the sections, because then the required size
376 // depends on the order, in which the sections are allocated.
377 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
378 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
379 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
382 // compute stub buffer size for the given section
383 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
384 const SectionRef &Section) {
385 unsigned StubSize = getMaxStubSize();
389 // FIXME: this is an inefficient way to handle this. We should computed the
390 // necessary section allocation size in loadObject by walking all the sections
392 unsigned StubBufSize = 0;
393 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
395 section_iterator RelSecI = SI->getRelocatedSection();
396 if (!(RelSecI == Section))
399 for (const RelocationRef &Reloc : SI->relocations()) {
401 StubBufSize += StubSize;
405 // Get section data size and alignment
406 uint64_t DataSize = Section.getSize();
407 uint64_t Alignment64 = Section.getAlignment();
409 // Add stubbuf size alignment
410 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
411 unsigned StubAlignment = getStubAlignment();
412 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
413 if (StubAlignment > EndAlignment)
414 StubBufSize += StubAlignment - EndAlignment;
418 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
419 unsigned Size) const {
421 if (IsTargetLittleEndian) {
424 Result = (Result << 8) | *Src--;
427 Result = (Result << 8) | *Src++;
432 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
433 unsigned Size) const {
434 if (IsTargetLittleEndian) {
436 *Dst++ = Value & 0xFF;
442 *Dst-- = Value & 0xFF;
448 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
449 CommonSymbolList &CommonSymbols) {
450 if (CommonSymbols.empty())
453 uint64_t CommonSize = 0;
454 CommonSymbolList SymbolsToAllocate;
456 DEBUG(dbgs() << "Processing common symbols...\n");
458 for (const auto &Sym : CommonSymbols) {
460 Check(Sym.getName(Name));
462 // Skip common symbols already elsewhere.
463 if (GlobalSymbolTable.count(Name) ||
464 MemMgr->getSymbolAddressInLogicalDylib(Name)) {
465 DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name
472 Check(Sym.getAlignment(Align));
473 Check(Sym.getSize(Size));
475 CommonSize += Align + Size;
476 SymbolsToAllocate.push_back(Sym);
479 // Allocate memory for the section
480 unsigned SectionID = Sections.size();
481 uint8_t *Addr = MemMgr->allocateDataSection(CommonSize, sizeof(void *),
482 SectionID, StringRef(), false);
484 report_fatal_error("Unable to allocate memory for common symbols!");
486 Sections.push_back(SectionEntry("<common symbols>", Addr, CommonSize, 0));
487 memset(Addr, 0, CommonSize);
489 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
490 << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
492 // Assign the address of each symbol
493 for (auto &Sym : SymbolsToAllocate) {
497 Check(Sym.getAlignment(Align));
498 Check(Sym.getSize(Size));
499 Check(Sym.getName(Name));
501 // This symbol has an alignment requirement.
502 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
504 Offset += AlignOffset;
506 uint32_t Flags = Sym.getFlags();
507 SymbolInfo::Visibility Vis =
508 (Flags & SymbolRef::SF_Exported) ?
509 SymbolInfo::Default : SymbolInfo::Hidden;
510 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
511 << format("%p", Addr) << "\n");
512 GlobalSymbolTable[Name] = SymbolInfo(SectionID, Offset, Vis);
518 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
519 const SectionRef &Section, bool IsCode) {
522 Check(Section.getContents(data));
523 uint64_t Alignment64 = Section.getAlignment();
525 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
526 unsigned PaddingSize = 0;
527 unsigned StubBufSize = 0;
529 bool IsRequired = isRequiredForExecution(Section);
530 bool IsVirtual = Section.isVirtual();
531 bool IsZeroInit = isZeroInit(Section);
532 bool IsReadOnly = isReadOnlyData(Section);
533 uint64_t DataSize = Section.getSize();
534 Check(Section.getName(Name));
536 StubBufSize = computeSectionStubBufSize(Obj, Section);
538 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
539 // with zeroes added at the end. For MachO objects, this section has a
540 // slightly different name, so this won't have any effect for MachO objects.
541 if (Name == ".eh_frame")
545 unsigned SectionID = Sections.size();
547 const char *pData = nullptr;
549 // Some sections, such as debug info, don't need to be loaded for execution.
550 // Leave those where they are.
552 Allocate = DataSize + PaddingSize + StubBufSize;
553 Addr = IsCode ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID,
555 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID,
558 report_fatal_error("Unable to allocate section memory!");
560 // Virtual sections have no data in the object image, so leave pData = 0
564 // Zero-initialize or copy the data from the image
565 if (IsZeroInit || IsVirtual)
566 memset(Addr, 0, DataSize);
568 memcpy(Addr, pData, DataSize);
570 // Fill in any extra bytes we allocated for padding
571 if (PaddingSize != 0) {
572 memset(Addr + DataSize, 0, PaddingSize);
573 // Update the DataSize variable so that the stub offset is set correctly.
574 DataSize += PaddingSize;
577 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
578 << " obj addr: " << format("%p", pData)
579 << " new addr: " << format("%p", Addr)
580 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
581 << " Allocate: " << Allocate << "\n");
583 // Even if we didn't load the section, we need to record an entry for it
584 // to handle later processing (and by 'handle' I mean don't do anything
585 // with these sections).
588 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
589 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
590 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
591 << " Allocate: " << Allocate << "\n");
594 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
597 Checker->registerSection(Obj.getFileName(), SectionID);
602 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
603 const SectionRef &Section,
605 ObjSectionToIDMap &LocalSections) {
607 unsigned SectionID = 0;
608 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
609 if (i != LocalSections.end())
610 SectionID = i->second;
612 SectionID = emitSection(Obj, Section, IsCode);
613 LocalSections[Section] = SectionID;
618 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
619 unsigned SectionID) {
620 Relocations[SectionID].push_back(RE);
623 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
624 StringRef SymbolName) {
625 // Relocation by symbol. If the symbol is found in the global symbol table,
626 // create an appropriate section relocation. Otherwise, add it to
627 // ExternalSymbolRelocations.
628 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
629 if (Loc == GlobalSymbolTable.end()) {
630 ExternalSymbolRelocations[SymbolName].push_back(RE);
632 // Copy the RE since we want to modify its addend.
633 RelocationEntry RECopy = RE;
634 const auto &SymInfo = Loc->second;
635 RECopy.Addend += SymInfo.getOffset();
636 Relocations[SymInfo.getSectionID()].push_back(RECopy);
640 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
641 unsigned AbiVariant) {
642 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
643 // This stub has to be able to access the full address space,
644 // since symbol lookup won't necessarily find a handy, in-range,
645 // PLT stub for functions which could be anywhere.
646 // Stub can use ip0 (== x16) to calculate address
647 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
648 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
649 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
650 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
651 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
654 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
655 // TODO: There is only ARM far stub now. We should add the Thumb stub,
656 // and stubs for branches Thumb - ARM and ARM - Thumb.
657 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
659 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
660 // 0: 3c190000 lui t9,%hi(addr).
661 // 4: 27390000 addiu t9,t9,%lo(addr).
662 // 8: 03200008 jr t9.
664 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
665 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
667 writeBytesUnaligned(LuiT9Instr, Addr, 4);
668 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
669 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
670 writeBytesUnaligned(NopInstr, Addr+12, 4);
672 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
673 // Depending on which version of the ELF ABI is in use, we need to
674 // generate one of two variants of the stub. They both start with
675 // the same sequence to load the target address into r12.
676 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
677 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
678 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
679 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
680 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
681 if (AbiVariant == 2) {
682 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
683 // The address is already in r12 as required by the ABI. Branch to it.
684 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
685 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
686 writeInt32BE(Addr+28, 0x4E800420); // bctr
688 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
689 // Load the function address on r11 and sets it to control register. Also
690 // loads the function TOC in r2 and environment pointer to r11.
691 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
692 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
693 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
694 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
695 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
696 writeInt32BE(Addr+40, 0x4E800420); // bctr
699 } else if (Arch == Triple::systemz) {
700 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
701 writeInt16BE(Addr+2, 0x0000);
702 writeInt16BE(Addr+4, 0x0004);
703 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
704 // 8-byte address stored at Addr + 8
706 } else if (Arch == Triple::x86_64) {
708 *(Addr+1) = 0x25; // rip
709 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
710 } else if (Arch == Triple::x86) {
711 *Addr = 0xE9; // 32-bit pc-relative jump.
716 // Assign an address to a symbol name and resolve all the relocations
717 // associated with it.
718 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
720 // The address to use for relocation resolution is not
721 // the address of the local section buffer. We must be doing
722 // a remote execution environment of some sort. Relocations can't
723 // be applied until all the sections have been moved. The client must
724 // trigger this with a call to MCJIT::finalize() or
725 // RuntimeDyld::resolveRelocations().
727 // Addr is a uint64_t because we can't assume the pointer width
728 // of the target is the same as that of the host. Just use a generic
729 // "big enough" type.
730 DEBUG(dbgs() << "Reassigning address for section "
731 << SectionID << " (" << Sections[SectionID].Name << "): "
732 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
733 << format("0x%016" PRIx64, Addr) << "\n");
734 Sections[SectionID].LoadAddress = Addr;
737 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
739 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
740 const RelocationEntry &RE = Relocs[i];
741 // Ignore relocations for sections that were not loaded
742 if (Sections[RE.SectionID].Address == nullptr)
744 resolveRelocation(RE, Value);
748 void RuntimeDyldImpl::resolveExternalSymbols() {
749 while (!ExternalSymbolRelocations.empty()) {
750 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
752 StringRef Name = i->first();
753 if (Name.size() == 0) {
754 // This is an absolute symbol, use an address of zero.
755 DEBUG(dbgs() << "Resolving absolute relocations."
757 RelocationList &Relocs = i->second;
758 resolveRelocationList(Relocs, 0);
761 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
762 if (Loc == GlobalSymbolTable.end()) {
763 // This is an external symbol, try to get its address from
765 Addr = MemMgr->getSymbolAddress(Name.data());
766 // The call to getSymbolAddress may have caused additional modules to
767 // be loaded, which may have added new entries to the
768 // ExternalSymbolRelocations map. Consquently, we need to update our
769 // iterator. This is also why retrieval of the relocation list
770 // associated with this symbol is deferred until below this point.
771 // New entries may have been added to the relocation list.
772 i = ExternalSymbolRelocations.find(Name);
774 // We found the symbol in our global table. It was probably in a
775 // Module that we loaded previously.
776 const auto &SymInfo = Loc->second;
777 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
781 // If we didn't find the symbol yet, and it is present in the weak symbol
782 // table, the definition from this object file needs to be used, so emit
785 RTDyldSymbolTable::const_iterator Loc = WeakSymbolTable.find(Name);
786 if (Loc != WeakSymbolTable.end()) {
787 SymbolInfo SymInfo = Loc->second;
788 Addr = getSectionLoadAddress(SymInfo.getSectionID()) + SymInfo.getOffset();
789 // Since the weak symbol is now, materialized, add it to the
790 // GlobalSymbolTable. If somebody later asks the ExecutionEngine
791 // for the address of this symbol that's where it'll look
792 GlobalSymbolTable[Name] = SymInfo;
796 // FIXME: Implement error handling that doesn't kill the host program!
798 report_fatal_error("Program used external function '" + Name +
799 "' which could not be resolved!");
801 updateGOTEntries(Name, Addr);
802 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
803 << format("0x%lx", Addr) << "\n");
804 // This list may have been updated when we called getSymbolAddress, so
805 // don't change this code to get the list earlier.
806 RelocationList &Relocs = i->second;
807 resolveRelocationList(Relocs, Addr);
810 ExternalSymbolRelocations.erase(i);
812 WeakSymbolTable.clear();
815 //===----------------------------------------------------------------------===//
816 // RuntimeDyld class implementation
818 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
819 StringRef SectionName) const {
820 for (unsigned I = BeginIdx; I != EndIdx; ++I)
821 if (RTDyld.Sections[I].Name == SectionName)
822 return RTDyld.Sections[I].LoadAddress;
827 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
828 // FIXME: There's a potential issue lurking here if a single instance of
829 // RuntimeDyld is used to load multiple objects. The current implementation
830 // associates a single memory manager with a RuntimeDyld instance. Even
831 // though the public class spawns a new 'impl' instance for each load,
832 // they share a single memory manager. This can become a problem when page
833 // permissions are applied.
836 ProcessAllSections = false;
840 RuntimeDyld::~RuntimeDyld() {}
842 static std::unique_ptr<RuntimeDyldELF>
843 createRuntimeDyldELF(RTDyldMemoryManager *MM, bool ProcessAllSections,
844 RuntimeDyldCheckerImpl *Checker) {
845 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM));
846 Dyld->setProcessAllSections(ProcessAllSections);
847 Dyld->setRuntimeDyldChecker(Checker);
851 static std::unique_ptr<RuntimeDyldMachO>
852 createRuntimeDyldMachO(Triple::ArchType Arch, RTDyldMemoryManager *MM,
853 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
854 std::unique_ptr<RuntimeDyldMachO> Dyld(RuntimeDyldMachO::create(Arch, MM));
855 Dyld->setProcessAllSections(ProcessAllSections);
856 Dyld->setRuntimeDyldChecker(Checker);
860 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
861 RuntimeDyld::loadObject(const ObjectFile &Obj) {
864 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
865 else if (Obj.isMachO())
866 Dyld = createRuntimeDyldMachO(
867 static_cast<Triple::ArchType>(Obj.getArch()), MM,
868 ProcessAllSections, Checker);
870 report_fatal_error("Incompatible object format!");
873 if (!Dyld->isCompatibleFile(Obj))
874 report_fatal_error("Incompatible object format!");
876 return Dyld->loadObject(Obj);
879 void *RuntimeDyld::getSymbolAddress(StringRef Name) const {
882 return Dyld->getSymbolAddress(Name);
885 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) const {
888 return Dyld->getSymbolLoadAddress(Name);
891 uint64_t RuntimeDyld::getExportedSymbolLoadAddress(StringRef Name) const {
894 return Dyld->getExportedSymbolLoadAddress(Name);
897 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
899 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
900 Dyld->reassignSectionAddress(SectionID, Addr);
903 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
904 uint64_t TargetAddress) {
905 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
908 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
910 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
912 void RuntimeDyld::registerEHFrames() {
914 Dyld->registerEHFrames();
917 void RuntimeDyld::deregisterEHFrames() {
919 Dyld->deregisterEHFrames();
922 } // end namespace llvm