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 "JITRegistrar.h"
16 #include "ObjectImageCommon.h"
17 #include "RuntimeDyldCheckerImpl.h"
18 #include "RuntimeDyldELF.h"
19 #include "RuntimeDyldImpl.h"
20 #include "RuntimeDyldMachO.h"
21 #include "llvm/Object/ELF.h"
22 #include "llvm/Support/MathExtras.h"
23 #include "llvm/Support/MutexGuard.h"
26 using namespace llvm::object;
28 #define DEBUG_TYPE "dyld"
30 // Empty out-of-line virtual destructor as the key function.
31 RuntimeDyldImpl::~RuntimeDyldImpl() {}
33 // Pin the JITRegistrar's and ObjectImage*'s vtables to this file.
34 void JITRegistrar::anchor() {}
35 void ObjectImage::anchor() {}
36 void ObjectImageCommon::anchor() {}
40 void RuntimeDyldImpl::registerEHFrames() {}
42 void RuntimeDyldImpl::deregisterEHFrames() {}
45 static void dumpSectionMemory(const SectionEntry &S, StringRef State) {
46 dbgs() << "----- Contents of section " << S.Name << " " << State << " -----";
48 const unsigned ColsPerRow = 16;
50 uint8_t *DataAddr = S.Address;
51 uint64_t LoadAddr = S.LoadAddress;
53 unsigned StartPadding = LoadAddr & 7;
54 unsigned BytesRemaining = S.Size;
57 dbgs() << "\n" << format("0x%08x", LoadAddr & ~(ColsPerRow - 1)) << ":";
58 while (StartPadding--)
62 while (BytesRemaining > 0) {
63 if ((LoadAddr & (ColsPerRow - 1)) == 0)
64 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr) << ":";
66 dbgs() << " " << format("%02x", *DataAddr);
77 // Resolve the relocations for all symbols we currently know about.
78 void RuntimeDyldImpl::resolveRelocations() {
79 MutexGuard locked(lock);
81 // First, resolve relocations associated with external symbols.
82 resolveExternalSymbols();
84 // Just iterate over the sections we have and resolve all the relocations
85 // in them. Gross overkill, but it gets the job done.
86 for (int i = 0, e = Sections.size(); i != e; ++i) {
87 // The Section here (Sections[i]) refers to the section in which the
88 // symbol for the relocation is located. The SectionID in the relocation
89 // entry provides the section to which the relocation will be applied.
90 uint64_t Addr = Sections[i].LoadAddress;
91 DEBUG(dbgs() << "Resolving relocations Section #" << i << "\t"
92 << format("0x%x", Addr) << "\n");
93 DEBUG(dumpSectionMemory(Sections[i], "before relocations"));
94 resolveRelocationList(Relocations[i], Addr);
95 DEBUG(dumpSectionMemory(Sections[i], "after relocations"));
100 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
101 uint64_t TargetAddress) {
102 MutexGuard locked(lock);
103 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
104 if (Sections[i].Address == LocalAddress) {
105 reassignSectionAddress(i, TargetAddress);
109 llvm_unreachable("Attempting to remap address of unknown section!");
112 static std::error_code getOffset(const SymbolRef &Sym, uint64_t &Result) {
114 if (std::error_code EC = Sym.getAddress(Address))
117 if (Address == UnknownAddressOrSize) {
118 Result = UnknownAddressOrSize;
119 return object_error::success;
122 const ObjectFile *Obj = Sym.getObject();
123 section_iterator SecI(Obj->section_begin());
124 if (std::error_code EC = Sym.getSection(SecI))
127 if (SecI == Obj->section_end()) {
128 Result = UnknownAddressOrSize;
129 return object_error::success;
132 uint64_t SectionAddress;
133 if (std::error_code EC = SecI->getAddress(SectionAddress))
136 Result = Address - SectionAddress;
137 return object_error::success;
140 std::unique_ptr<ObjectImage>
141 RuntimeDyldImpl::loadObject(std::unique_ptr<ObjectImage> Obj) {
142 MutexGuard locked(lock);
147 // Save information about our target
148 Arch = (Triple::ArchType)Obj->getArch();
149 IsTargetLittleEndian = Obj->getObjectFile()->isLittleEndian();
151 // Compute the memory size required to load all sections to be loaded
152 // and pass this information to the memory manager
153 if (MemMgr->needsToReserveAllocationSpace()) {
154 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
155 computeTotalAllocSize(*Obj, CodeSize, DataSizeRO, DataSizeRW);
156 MemMgr->reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
159 // Symbols found in this object
160 StringMap<SymbolLoc> LocalSymbols;
161 // Used sections from the object file
162 ObjSectionToIDMap LocalSections;
164 // Common symbols requiring allocation, with their sizes and alignments
165 CommonSymbolMap CommonSymbols;
166 // Maximum required total memory to allocate all common symbols
167 uint64_t CommonSize = 0;
170 DEBUG(dbgs() << "Parse symbols:\n");
171 for (symbol_iterator I = Obj->begin_symbols(), E = Obj->end_symbols(); I != E;
173 object::SymbolRef::Type SymType;
175 Check(I->getType(SymType));
176 Check(I->getName(Name));
178 uint32_t Flags = I->getFlags();
180 bool IsCommon = Flags & SymbolRef::SF_Common;
182 // Add the common symbols to a list. We'll allocate them all below.
183 if (!GlobalSymbolTable.count(Name)) {
185 Check(I->getAlignment(Align));
187 Check(I->getSize(Size));
188 CommonSize += Size + Align;
189 CommonSymbols[*I] = CommonSymbolInfo(Size, Align);
192 if (SymType == object::SymbolRef::ST_Function ||
193 SymType == object::SymbolRef::ST_Data ||
194 SymType == object::SymbolRef::ST_Unknown) {
196 StringRef SectionData;
198 section_iterator SI = Obj->end_sections();
199 Check(getOffset(*I, SectOffset));
200 Check(I->getSection(SI));
201 if (SI == Obj->end_sections())
203 Check(SI->getContents(SectionData));
204 Check(SI->isText(IsCode));
206 findOrEmitSection(*Obj, *SI, IsCode, LocalSections);
207 LocalSymbols[Name.data()] = SymbolLoc(SectionID, SectOffset);
208 DEBUG(dbgs() << "\tOffset: " << format("%p", (uintptr_t)SectOffset)
209 << " flags: " << Flags << " SID: " << SectionID);
210 GlobalSymbolTable[Name] = SymbolLoc(SectionID, SectOffset);
213 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name << "\n");
216 // Allocate common symbols
218 emitCommonSymbols(*Obj, CommonSymbols, CommonSize, GlobalSymbolTable);
220 // Parse and process relocations
221 DEBUG(dbgs() << "Parse relocations:\n");
222 for (section_iterator SI = Obj->begin_sections(), SE = Obj->end_sections();
224 unsigned SectionID = 0;
226 section_iterator RelocatedSection = SI->getRelocatedSection();
228 relocation_iterator I = SI->relocation_begin();
229 relocation_iterator E = SI->relocation_end();
231 if (I == E && !ProcessAllSections)
235 Check(RelocatedSection->isText(IsCode));
237 findOrEmitSection(*Obj, *RelocatedSection, IsCode, LocalSections);
238 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
241 I = processRelocationRef(SectionID, I, *Obj, LocalSections, LocalSymbols,
244 // If there is an attached checker, notify it about the stubs for this
245 // section so that they can be verified.
247 Checker->registerStubMap(Obj->getImageName(), SectionID, Stubs);
250 // Give the subclasses a chance to tie-up any loose ends.
251 finalizeLoad(*Obj, LocalSections);
256 // A helper method for computeTotalAllocSize.
257 // Computes the memory size required to allocate sections with the given sizes,
258 // assuming that all sections are allocated with the given alignment
260 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
261 uint64_t Alignment) {
262 uint64_t TotalSize = 0;
263 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
264 uint64_t AlignedSize =
265 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
266 TotalSize += AlignedSize;
271 // Compute an upper bound of the memory size that is required to load all
273 void RuntimeDyldImpl::computeTotalAllocSize(ObjectImage &Obj,
275 uint64_t &DataSizeRO,
276 uint64_t &DataSizeRW) {
277 // Compute the size of all sections required for execution
278 std::vector<uint64_t> CodeSectionSizes;
279 std::vector<uint64_t> ROSectionSizes;
280 std::vector<uint64_t> RWSectionSizes;
281 uint64_t MaxAlignment = sizeof(void *);
283 // Collect sizes of all sections to be loaded;
284 // also determine the max alignment of all sections
285 for (section_iterator SI = Obj.begin_sections(), SE = Obj.end_sections();
287 const SectionRef &Section = *SI;
290 Check(Section.isRequiredForExecution(IsRequired));
292 // Consider only the sections that are required to be loaded for execution
294 uint64_t DataSize = 0;
295 uint64_t Alignment64 = 0;
297 bool IsReadOnly = false;
299 Check(Section.getSize(DataSize));
300 Check(Section.getAlignment(Alignment64));
301 Check(Section.isText(IsCode));
302 Check(Section.isReadOnlyData(IsReadOnly));
303 Check(Section.getName(Name));
304 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
306 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
307 uint64_t SectionSize = DataSize + StubBufSize;
309 // The .eh_frame section (at least on Linux) needs an extra four bytes
311 // with zeroes added at the end. For MachO objects, this section has a
312 // slightly different name, so this won't have any effect for MachO
314 if (Name == ".eh_frame")
317 if (SectionSize > 0) {
318 // save the total size of the section
320 CodeSectionSizes.push_back(SectionSize);
321 } else if (IsReadOnly) {
322 ROSectionSizes.push_back(SectionSize);
324 RWSectionSizes.push_back(SectionSize);
326 // update the max alignment
327 if (Alignment > MaxAlignment) {
328 MaxAlignment = Alignment;
334 // Compute the size of all common symbols
335 uint64_t CommonSize = 0;
336 for (symbol_iterator I = Obj.begin_symbols(), E = Obj.end_symbols(); I != E;
338 uint32_t Flags = I->getFlags();
339 if (Flags & SymbolRef::SF_Common) {
340 // Add the common symbols to a list. We'll allocate them all below.
342 Check(I->getSize(Size));
346 if (CommonSize != 0) {
347 RWSectionSizes.push_back(CommonSize);
350 // Compute the required allocation space for each different type of sections
351 // (code, read-only data, read-write data) assuming that all sections are
352 // allocated with the max alignment. Note that we cannot compute with the
353 // individual alignments of the sections, because then the required size
354 // depends on the order, in which the sections are allocated.
355 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
356 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
357 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
360 // compute stub buffer size for the given section
361 unsigned RuntimeDyldImpl::computeSectionStubBufSize(ObjectImage &Obj,
362 const SectionRef &Section) {
363 unsigned StubSize = getMaxStubSize();
367 // FIXME: this is an inefficient way to handle this. We should computed the
368 // necessary section allocation size in loadObject by walking all the sections
370 unsigned StubBufSize = 0;
371 for (section_iterator SI = Obj.begin_sections(), SE = Obj.end_sections();
373 section_iterator RelSecI = SI->getRelocatedSection();
374 if (!(RelSecI == Section))
377 for (const RelocationRef &Reloc : SI->relocations()) {
379 StubBufSize += StubSize;
383 // Get section data size and alignment
384 uint64_t Alignment64;
386 Check(Section.getSize(DataSize));
387 Check(Section.getAlignment(Alignment64));
389 // Add stubbuf size alignment
390 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
391 unsigned StubAlignment = getStubAlignment();
392 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
393 if (StubAlignment > EndAlignment)
394 StubBufSize += StubAlignment - EndAlignment;
398 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
399 unsigned Size) const {
401 uint8_t *Dst = reinterpret_cast<uint8_t*>(&Result);
403 if (IsTargetLittleEndian == sys::IsLittleEndianHost) {
404 if (!sys::IsLittleEndianHost)
405 Dst += sizeof(Result) - Size;
406 memcpy(Dst, Src, Size);
409 for (unsigned i = 0; i < Size; ++i)
416 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
417 unsigned Size) const {
418 uint8_t *Src = reinterpret_cast<uint8_t*>(&Value);
419 if (IsTargetLittleEndian == sys::IsLittleEndianHost) {
420 if (!sys::IsLittleEndianHost)
421 Src += sizeof(Value) - Size;
422 memcpy(Dst, Src, Size);
425 for (unsigned i = 0; i < Size; ++i)
430 void RuntimeDyldImpl::emitCommonSymbols(ObjectImage &Obj,
431 const CommonSymbolMap &CommonSymbols,
433 SymbolTableMap &SymbolTable) {
434 // Allocate memory for the section
435 unsigned SectionID = Sections.size();
436 uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, sizeof(void *),
437 SectionID, StringRef(), false);
439 report_fatal_error("Unable to allocate memory for common symbols!");
441 Sections.push_back(SectionEntry("<common symbols>", Addr, TotalSize, 0));
442 memset(Addr, 0, TotalSize);
444 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
445 << format("%p", Addr) << " DataSize: " << TotalSize << "\n");
447 // Assign the address of each symbol
448 for (CommonSymbolMap::const_iterator it = CommonSymbols.begin(),
449 itEnd = CommonSymbols.end(); it != itEnd; ++it) {
450 uint64_t Size = it->second.first;
451 uint64_t Align = it->second.second;
453 it->first.getName(Name);
455 // This symbol has an alignment requirement.
456 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
458 Offset += AlignOffset;
459 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
460 << format("%p\n", Addr));
462 Obj.updateSymbolAddress(it->first, (uint64_t)Addr);
463 SymbolTable[Name.data()] = SymbolLoc(SectionID, Offset);
469 unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
470 const SectionRef &Section, bool IsCode) {
473 uint64_t Alignment64;
474 Check(Section.getContents(data));
475 Check(Section.getAlignment(Alignment64));
477 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
483 unsigned PaddingSize = 0;
484 unsigned StubBufSize = 0;
486 Check(Section.isRequiredForExecution(IsRequired));
487 Check(Section.isVirtual(IsVirtual));
488 Check(Section.isZeroInit(IsZeroInit));
489 Check(Section.isReadOnlyData(IsReadOnly));
490 Check(Section.getSize(DataSize));
491 Check(Section.getName(Name));
493 StubBufSize = computeSectionStubBufSize(Obj, Section);
495 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
496 // with zeroes added at the end. For MachO objects, this section has a
497 // slightly different name, so this won't have any effect for MachO objects.
498 if (Name == ".eh_frame")
502 unsigned SectionID = Sections.size();
504 const char *pData = nullptr;
506 // Some sections, such as debug info, don't need to be loaded for execution.
507 // Leave those where they are.
509 Allocate = DataSize + PaddingSize + StubBufSize;
510 Addr = IsCode ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID,
512 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID,
515 report_fatal_error("Unable to allocate section memory!");
517 // Virtual sections have no data in the object image, so leave pData = 0
521 // Zero-initialize or copy the data from the image
522 if (IsZeroInit || IsVirtual)
523 memset(Addr, 0, DataSize);
525 memcpy(Addr, pData, DataSize);
527 // Fill in any extra bytes we allocated for padding
528 if (PaddingSize != 0) {
529 memset(Addr + DataSize, 0, PaddingSize);
530 // Update the DataSize variable so that the stub offset is set correctly.
531 DataSize += PaddingSize;
534 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
535 << " obj addr: " << format("%p", pData)
536 << " new addr: " << format("%p", Addr)
537 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
538 << " Allocate: " << Allocate << "\n");
539 Obj.updateSectionAddress(Section, (uint64_t)Addr);
541 // Even if we didn't load the section, we need to record an entry for it
542 // to handle later processing (and by 'handle' I mean don't do anything
543 // with these sections).
546 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
547 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
548 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
549 << " Allocate: " << Allocate << "\n");
552 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
555 Checker->registerSection(Obj.getImageName(), SectionID);
560 unsigned RuntimeDyldImpl::findOrEmitSection(ObjectImage &Obj,
561 const SectionRef &Section,
563 ObjSectionToIDMap &LocalSections) {
565 unsigned SectionID = 0;
566 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
567 if (i != LocalSections.end())
568 SectionID = i->second;
570 SectionID = emitSection(Obj, Section, IsCode);
571 LocalSections[Section] = SectionID;
576 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
577 unsigned SectionID) {
578 Relocations[SectionID].push_back(RE);
581 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
582 StringRef SymbolName) {
583 // Relocation by symbol. If the symbol is found in the global symbol table,
584 // create an appropriate section relocation. Otherwise, add it to
585 // ExternalSymbolRelocations.
586 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
587 if (Loc == GlobalSymbolTable.end()) {
588 ExternalSymbolRelocations[SymbolName].push_back(RE);
590 // Copy the RE since we want to modify its addend.
591 RelocationEntry RECopy = RE;
592 RECopy.Addend += Loc->second.second;
593 Relocations[Loc->second.first].push_back(RECopy);
597 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
598 unsigned AbiVariant) {
599 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
600 // This stub has to be able to access the full address space,
601 // since symbol lookup won't necessarily find a handy, in-range,
602 // PLT stub for functions which could be anywhere.
603 uint32_t *StubAddr = (uint32_t *)Addr;
605 // Stub can use ip0 (== x16) to calculate address
606 *StubAddr = 0xd2e00010; // movz ip0, #:abs_g3:<addr>
608 *StubAddr = 0xf2c00010; // movk ip0, #:abs_g2_nc:<addr>
610 *StubAddr = 0xf2a00010; // movk ip0, #:abs_g1_nc:<addr>
612 *StubAddr = 0xf2800010; // movk ip0, #:abs_g0_nc:<addr>
614 *StubAddr = 0xd61f0200; // 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 uint32_t *StubAddr = (uint32_t *)Addr;
621 *StubAddr = 0xe51ff004; // ldr pc,<label>
622 return (uint8_t *)++StubAddr;
623 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
624 uint32_t *StubAddr = (uint32_t *)Addr;
625 // 0: 3c190000 lui t9,%hi(addr).
626 // 4: 27390000 addiu t9,t9,%lo(addr).
627 // 8: 03200008 jr t9.
629 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
630 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
632 *StubAddr = LuiT9Instr;
634 *StubAddr = AdduiT9Instr;
636 *StubAddr = JrT9Instr;
638 *StubAddr = NopInstr;
640 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
641 // Depending on which version of the ELF ABI is in use, we need to
642 // generate one of two variants of the stub. They both start with
643 // the same sequence to load the target address into r12.
644 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
645 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
646 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
647 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
648 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
649 if (AbiVariant == 2) {
650 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
651 // The address is already in r12 as required by the ABI. Branch to it.
652 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
653 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
654 writeInt32BE(Addr+28, 0x4E800420); // bctr
656 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
657 // Load the function address on r11 and sets it to control register. Also
658 // loads the function TOC in r2 and environment pointer to r11.
659 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
660 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
661 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
662 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
663 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
664 writeInt32BE(Addr+40, 0x4E800420); // bctr
667 } else if (Arch == Triple::systemz) {
668 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
669 writeInt16BE(Addr+2, 0x0000);
670 writeInt16BE(Addr+4, 0x0004);
671 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
672 // 8-byte address stored at Addr + 8
674 } else if (Arch == Triple::x86_64) {
676 *(Addr+1) = 0x25; // rip
677 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
678 } else if (Arch == Triple::x86) {
679 *Addr = 0xE9; // 32-bit pc-relative jump.
684 // Assign an address to a symbol name and resolve all the relocations
685 // associated with it.
686 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
688 // The address to use for relocation resolution is not
689 // the address of the local section buffer. We must be doing
690 // a remote execution environment of some sort. Relocations can't
691 // be applied until all the sections have been moved. The client must
692 // trigger this with a call to MCJIT::finalize() or
693 // RuntimeDyld::resolveRelocations().
695 // Addr is a uint64_t because we can't assume the pointer width
696 // of the target is the same as that of the host. Just use a generic
697 // "big enough" type.
698 DEBUG(dbgs() << "Reassigning address for section "
699 << SectionID << " (" << Sections[SectionID].Name << "): "
700 << format("0x%016x", Sections[SectionID].LoadAddress) << " -> "
701 << format("0x%016x", Addr) << "\n");
702 Sections[SectionID].LoadAddress = Addr;
705 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
707 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
708 const RelocationEntry &RE = Relocs[i];
709 // Ignore relocations for sections that were not loaded
710 if (Sections[RE.SectionID].Address == nullptr)
712 resolveRelocation(RE, Value);
716 void RuntimeDyldImpl::resolveExternalSymbols() {
717 while (!ExternalSymbolRelocations.empty()) {
718 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
720 StringRef Name = i->first();
721 if (Name.size() == 0) {
722 // This is an absolute symbol, use an address of zero.
723 DEBUG(dbgs() << "Resolving absolute relocations."
725 RelocationList &Relocs = i->second;
726 resolveRelocationList(Relocs, 0);
729 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(Name);
730 if (Loc == GlobalSymbolTable.end()) {
731 // This is an external symbol, try to get its address from
733 Addr = MemMgr->getSymbolAddress(Name.data());
734 // The call to getSymbolAddress may have caused additional modules to
735 // be loaded, which may have added new entries to the
736 // ExternalSymbolRelocations map. Consquently, we need to update our
737 // iterator. This is also why retrieval of the relocation list
738 // associated with this symbol is deferred until below this point.
739 // New entries may have been added to the relocation list.
740 i = ExternalSymbolRelocations.find(Name);
742 // We found the symbol in our global table. It was probably in a
743 // Module that we loaded previously.
744 SymbolLoc SymLoc = Loc->second;
745 Addr = getSectionLoadAddress(SymLoc.first) + SymLoc.second;
748 // FIXME: Implement error handling that doesn't kill the host program!
750 report_fatal_error("Program used external function '" + Name +
751 "' which could not be resolved!");
753 updateGOTEntries(Name, Addr);
754 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
755 << format("0x%lx", Addr) << "\n");
756 // This list may have been updated when we called getSymbolAddress, so
757 // don't change this code to get the list earlier.
758 RelocationList &Relocs = i->second;
759 resolveRelocationList(Relocs, Addr);
762 ExternalSymbolRelocations.erase(i);
766 //===----------------------------------------------------------------------===//
767 // RuntimeDyld class implementation
768 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
769 // FIXME: There's a potential issue lurking here if a single instance of
770 // RuntimeDyld is used to load multiple objects. The current implementation
771 // associates a single memory manager with a RuntimeDyld instance. Even
772 // though the public class spawns a new 'impl' instance for each load,
773 // they share a single memory manager. This can become a problem when page
774 // permissions are applied.
777 ProcessAllSections = false;
781 RuntimeDyld::~RuntimeDyld() {}
783 static std::unique_ptr<RuntimeDyldELF>
784 createRuntimeDyldELF(RTDyldMemoryManager *MM, bool ProcessAllSections,
785 RuntimeDyldCheckerImpl *Checker) {
786 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM));
787 Dyld->setProcessAllSections(ProcessAllSections);
788 Dyld->setRuntimeDyldChecker(Checker);
792 static std::unique_ptr<RuntimeDyldMachO>
793 createRuntimeDyldMachO(Triple::ArchType Arch, RTDyldMemoryManager *MM,
794 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
795 std::unique_ptr<RuntimeDyldMachO> Dyld(RuntimeDyldMachO::create(Arch, MM));
796 Dyld->setProcessAllSections(ProcessAllSections);
797 Dyld->setRuntimeDyldChecker(Checker);
801 std::unique_ptr<ObjectImage>
802 RuntimeDyld::loadObject(std::unique_ptr<ObjectFile> InputObject) {
803 std::unique_ptr<ObjectImage> InputImage;
805 ObjectFile &Obj = *InputObject;
807 if (InputObject->isELF()) {
808 InputImage.reset(RuntimeDyldELF::createObjectImageFromFile(std::move(InputObject)));
810 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
811 } else if (InputObject->isMachO()) {
812 InputImage.reset(RuntimeDyldMachO::createObjectImageFromFile(std::move(InputObject)));
814 Dyld = createRuntimeDyldMachO(
815 static_cast<Triple::ArchType>(InputImage->getArch()), MM,
816 ProcessAllSections, Checker);
818 report_fatal_error("Incompatible object format!");
820 if (!Dyld->isCompatibleFile(&Obj))
821 report_fatal_error("Incompatible object format!");
823 return Dyld->loadObject(std::move(InputImage));
826 std::unique_ptr<ObjectImage>
827 RuntimeDyld::loadObject(std::unique_ptr<ObjectBuffer> InputBuffer) {
828 std::unique_ptr<ObjectImage> InputImage;
829 sys::fs::file_magic Type = sys::fs::identify_magic(InputBuffer->getBuffer());
830 auto *InputBufferPtr = InputBuffer.get();
833 case sys::fs::file_magic::elf_relocatable:
834 case sys::fs::file_magic::elf_executable:
835 case sys::fs::file_magic::elf_shared_object:
836 case sys::fs::file_magic::elf_core:
837 InputImage = RuntimeDyldELF::createObjectImage(std::move(InputBuffer));
839 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
841 case sys::fs::file_magic::macho_object:
842 case sys::fs::file_magic::macho_executable:
843 case sys::fs::file_magic::macho_fixed_virtual_memory_shared_lib:
844 case sys::fs::file_magic::macho_core:
845 case sys::fs::file_magic::macho_preload_executable:
846 case sys::fs::file_magic::macho_dynamically_linked_shared_lib:
847 case sys::fs::file_magic::macho_dynamic_linker:
848 case sys::fs::file_magic::macho_bundle:
849 case sys::fs::file_magic::macho_dynamically_linked_shared_lib_stub:
850 case sys::fs::file_magic::macho_dsym_companion:
851 InputImage = RuntimeDyldMachO::createObjectImage(std::move(InputBuffer));
853 Dyld = createRuntimeDyldMachO(
854 static_cast<Triple::ArchType>(InputImage->getArch()), MM,
855 ProcessAllSections, Checker);
857 case sys::fs::file_magic::unknown:
858 case sys::fs::file_magic::bitcode:
859 case sys::fs::file_magic::archive:
860 case sys::fs::file_magic::coff_object:
861 case sys::fs::file_magic::coff_import_library:
862 case sys::fs::file_magic::pecoff_executable:
863 case sys::fs::file_magic::macho_universal_binary:
864 case sys::fs::file_magic::windows_resource:
865 report_fatal_error("Incompatible object format!");
868 if (!Dyld->isCompatibleFormat(InputBufferPtr))
869 report_fatal_error("Incompatible object format!");
871 return Dyld->loadObject(std::move(InputImage));
874 void *RuntimeDyld::getSymbolAddress(StringRef Name) const {
877 return Dyld->getSymbolAddress(Name);
880 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) const {
883 return Dyld->getSymbolLoadAddress(Name);
886 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
888 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
889 Dyld->reassignSectionAddress(SectionID, Addr);
892 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
893 uint64_t TargetAddress) {
894 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
897 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
899 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
901 void RuntimeDyld::registerEHFrames() {
903 Dyld->registerEHFrames();
906 void RuntimeDyld::deregisterEHFrames() {
908 Dyld->deregisterEHFrames();
911 } // end namespace llvm