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 if (S.Address == nullptr) {
49 dbgs() << "\n <section not emitted>\n";
53 const unsigned ColsPerRow = 16;
55 uint8_t *DataAddr = S.Address;
56 uint64_t LoadAddr = S.LoadAddress;
58 unsigned StartPadding = LoadAddr & (ColsPerRow - 1);
59 unsigned BytesRemaining = S.Size;
62 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr & ~(ColsPerRow - 1)) << ":";
63 while (StartPadding--)
67 while (BytesRemaining > 0) {
68 if ((LoadAddr & (ColsPerRow - 1)) == 0)
69 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr) << ":";
71 dbgs() << " " << format("%02x", *DataAddr);
82 // Resolve the relocations for all symbols we currently know about.
83 void RuntimeDyldImpl::resolveRelocations() {
84 MutexGuard locked(lock);
86 // First, resolve relocations associated with external symbols.
87 resolveExternalSymbols();
89 // Just iterate over the sections we have and resolve all the relocations
90 // in them. Gross overkill, but it gets the job done.
91 for (int i = 0, e = Sections.size(); i != e; ++i) {
92 // The Section here (Sections[i]) refers to the section in which the
93 // symbol for the relocation is located. The SectionID in the relocation
94 // entry provides the section to which the relocation will be applied.
95 uint64_t Addr = Sections[i].LoadAddress;
96 DEBUG(dbgs() << "Resolving relocations Section #" << i << "\t"
97 << format("0x%x", Addr) << "\n");
98 DEBUG(dumpSectionMemory(Sections[i], "before relocations"));
99 resolveRelocationList(Relocations[i], Addr);
100 DEBUG(dumpSectionMemory(Sections[i], "after relocations"));
101 Relocations.erase(i);
105 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
106 uint64_t TargetAddress) {
107 MutexGuard locked(lock);
108 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
109 if (Sections[i].Address == LocalAddress) {
110 reassignSectionAddress(i, TargetAddress);
114 llvm_unreachable("Attempting to remap address of unknown section!");
117 static std::error_code getOffset(const SymbolRef &Sym, uint64_t &Result) {
119 if (std::error_code EC = Sym.getAddress(Address))
122 if (Address == UnknownAddressOrSize) {
123 Result = UnknownAddressOrSize;
124 return object_error::success;
127 const ObjectFile *Obj = Sym.getObject();
128 section_iterator SecI(Obj->section_begin());
129 if (std::error_code EC = Sym.getSection(SecI))
132 if (SecI == Obj->section_end()) {
133 Result = UnknownAddressOrSize;
134 return object_error::success;
137 uint64_t SectionAddress = SecI->getAddress();
138 Result = Address - SectionAddress;
139 return object_error::success;
142 std::unique_ptr<ObjectImage>
143 RuntimeDyldImpl::loadObject(std::unique_ptr<ObjectImage> Obj) {
144 MutexGuard locked(lock);
149 // Save information about our target
150 Arch = (Triple::ArchType)Obj->getArch();
151 IsTargetLittleEndian = Obj->getObjectFile()->isLittleEndian();
153 // Compute the memory size required to load all sections to be loaded
154 // and pass this information to the memory manager
155 if (MemMgr->needsToReserveAllocationSpace()) {
156 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
157 computeTotalAllocSize(*Obj, CodeSize, DataSizeRO, DataSizeRW);
158 MemMgr->reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
161 // Symbols found in this object
162 StringMap<SymbolLoc> LocalSymbols;
163 // Used sections from the object file
164 ObjSectionToIDMap LocalSections;
166 // Common symbols requiring allocation, with their sizes and alignments
167 CommonSymbolMap CommonSymbols;
168 // Maximum required total memory to allocate all common symbols
169 uint64_t CommonSize = 0;
172 DEBUG(dbgs() << "Parse symbols:\n");
173 for (symbol_iterator I = Obj->begin_symbols(), E = Obj->end_symbols(); I != E;
175 object::SymbolRef::Type SymType;
177 Check(I->getType(SymType));
178 Check(I->getName(Name));
180 uint32_t Flags = I->getFlags();
182 bool IsCommon = Flags & SymbolRef::SF_Common;
184 // Add the common symbols to a list. We'll allocate them all below.
185 if (!GlobalSymbolTable.count(Name)) {
187 Check(I->getAlignment(Align));
189 Check(I->getSize(Size));
190 CommonSize += Size + Align;
191 CommonSymbols[*I] = CommonSymbolInfo(Size, Align);
194 if (SymType == object::SymbolRef::ST_Function ||
195 SymType == object::SymbolRef::ST_Data ||
196 SymType == object::SymbolRef::ST_Unknown) {
198 StringRef SectionData;
199 section_iterator SI = Obj->end_sections();
200 Check(getOffset(*I, SectOffset));
201 Check(I->getSection(SI));
202 if (SI == Obj->end_sections())
204 Check(SI->getContents(SectionData));
205 bool IsCode = SI->isText();
207 findOrEmitSection(*Obj, *SI, IsCode, LocalSections);
208 LocalSymbols[Name.data()] = SymbolLoc(SectionID, SectOffset);
209 DEBUG(dbgs() << "\tOffset: " << format("%p", (uintptr_t)SectOffset)
210 << " flags: " << Flags << " SID: " << SectionID);
211 GlobalSymbolTable[Name] = SymbolLoc(SectionID, SectOffset);
214 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name << "\n");
217 // Allocate common symbols
219 emitCommonSymbols(*Obj, CommonSymbols, CommonSize, GlobalSymbolTable);
221 // Parse and process relocations
222 DEBUG(dbgs() << "Parse relocations:\n");
223 for (section_iterator SI = Obj->begin_sections(), SE = Obj->end_sections();
225 unsigned SectionID = 0;
227 section_iterator RelocatedSection = SI->getRelocatedSection();
229 relocation_iterator I = SI->relocation_begin();
230 relocation_iterator E = SI->relocation_end();
232 if (I == E && !ProcessAllSections)
235 bool IsCode = RelocatedSection->isText();
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;
289 bool IsRequired = Section.isRequiredForExecution();
291 // Consider only the sections that are required to be loaded for execution
294 uint64_t DataSize = Section.getSize();
295 uint64_t Alignment64 = Section.getAlignment();
296 bool IsCode = Section.isText();
297 bool IsReadOnly = Section.isReadOnlyData();
298 Check(Section.getName(Name));
299 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
301 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
302 uint64_t SectionSize = DataSize + StubBufSize;
304 // The .eh_frame section (at least on Linux) needs an extra four bytes
306 // with zeroes added at the end. For MachO objects, this section has a
307 // slightly different name, so this won't have any effect for MachO
309 if (Name == ".eh_frame")
312 if (SectionSize > 0) {
313 // save the total size of the section
315 CodeSectionSizes.push_back(SectionSize);
316 } else if (IsReadOnly) {
317 ROSectionSizes.push_back(SectionSize);
319 RWSectionSizes.push_back(SectionSize);
321 // update the max alignment
322 if (Alignment > MaxAlignment) {
323 MaxAlignment = Alignment;
329 // Compute the size of all common symbols
330 uint64_t CommonSize = 0;
331 for (symbol_iterator I = Obj.begin_symbols(), E = Obj.end_symbols(); I != E;
333 uint32_t Flags = I->getFlags();
334 if (Flags & SymbolRef::SF_Common) {
335 // Add the common symbols to a list. We'll allocate them all below.
337 Check(I->getSize(Size));
341 if (CommonSize != 0) {
342 RWSectionSizes.push_back(CommonSize);
345 // Compute the required allocation space for each different type of sections
346 // (code, read-only data, read-write data) assuming that all sections are
347 // allocated with the max alignment. Note that we cannot compute with the
348 // individual alignments of the sections, because then the required size
349 // depends on the order, in which the sections are allocated.
350 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
351 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
352 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
355 // compute stub buffer size for the given section
356 unsigned RuntimeDyldImpl::computeSectionStubBufSize(ObjectImage &Obj,
357 const SectionRef &Section) {
358 unsigned StubSize = getMaxStubSize();
362 // FIXME: this is an inefficient way to handle this. We should computed the
363 // necessary section allocation size in loadObject by walking all the sections
365 unsigned StubBufSize = 0;
366 for (section_iterator SI = Obj.begin_sections(), SE = Obj.end_sections();
368 section_iterator RelSecI = SI->getRelocatedSection();
369 if (!(RelSecI == Section))
372 for (const RelocationRef &Reloc : SI->relocations()) {
374 StubBufSize += StubSize;
378 // Get section data size and alignment
379 uint64_t DataSize = Section.getSize();
380 uint64_t Alignment64 = Section.getAlignment();
382 // Add stubbuf size alignment
383 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
384 unsigned StubAlignment = getStubAlignment();
385 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
386 if (StubAlignment > EndAlignment)
387 StubBufSize += StubAlignment - EndAlignment;
391 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
392 unsigned Size) const {
394 if (IsTargetLittleEndian) {
397 Result = (Result << 8) | *Src--;
400 Result = (Result << 8) | *Src++;
405 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
406 unsigned Size) const {
407 if (IsTargetLittleEndian) {
409 *Dst++ = Value & 0xFF;
415 *Dst-- = Value & 0xFF;
421 void RuntimeDyldImpl::emitCommonSymbols(ObjectImage &Obj,
422 const CommonSymbolMap &CommonSymbols,
424 SymbolTableMap &SymbolTable) {
425 // Allocate memory for the section
426 unsigned SectionID = Sections.size();
427 uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, sizeof(void *),
428 SectionID, StringRef(), false);
430 report_fatal_error("Unable to allocate memory for common symbols!");
432 Sections.push_back(SectionEntry("<common symbols>", Addr, TotalSize, 0));
433 memset(Addr, 0, TotalSize);
435 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
436 << format("%p", Addr) << " DataSize: " << TotalSize << "\n");
438 // Assign the address of each symbol
439 for (CommonSymbolMap::const_iterator it = CommonSymbols.begin(),
440 itEnd = CommonSymbols.end(); it != itEnd; ++it) {
441 uint64_t Size = it->second.first;
442 uint64_t Align = it->second.second;
444 it->first.getName(Name);
446 // This symbol has an alignment requirement.
447 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
449 Offset += AlignOffset;
450 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
451 << format("%p\n", Addr));
453 Obj.updateSymbolAddress(it->first, (uint64_t)Addr);
454 SymbolTable[Name.data()] = SymbolLoc(SectionID, Offset);
460 unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
461 const SectionRef &Section, bool IsCode) {
464 Check(Section.getContents(data));
465 uint64_t Alignment64 = Section.getAlignment();
467 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
468 unsigned PaddingSize = 0;
469 unsigned StubBufSize = 0;
471 bool IsRequired = Section.isRequiredForExecution();
472 bool IsVirtual = Section.isVirtual();
473 bool IsZeroInit = Section.isZeroInit();
474 bool IsReadOnly = Section.isReadOnlyData();
475 uint64_t DataSize = Section.getSize();
476 Check(Section.getName(Name));
478 StubBufSize = computeSectionStubBufSize(Obj, Section);
480 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
481 // with zeroes added at the end. For MachO objects, this section has a
482 // slightly different name, so this won't have any effect for MachO objects.
483 if (Name == ".eh_frame")
487 unsigned SectionID = Sections.size();
489 const char *pData = nullptr;
491 // Some sections, such as debug info, don't need to be loaded for execution.
492 // Leave those where they are.
494 Allocate = DataSize + PaddingSize + StubBufSize;
495 Addr = IsCode ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID,
497 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID,
500 report_fatal_error("Unable to allocate section memory!");
502 // Virtual sections have no data in the object image, so leave pData = 0
506 // Zero-initialize or copy the data from the image
507 if (IsZeroInit || IsVirtual)
508 memset(Addr, 0, DataSize);
510 memcpy(Addr, pData, DataSize);
512 // Fill in any extra bytes we allocated for padding
513 if (PaddingSize != 0) {
514 memset(Addr + DataSize, 0, PaddingSize);
515 // Update the DataSize variable so that the stub offset is set correctly.
516 DataSize += PaddingSize;
519 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
520 << " obj addr: " << format("%p", pData)
521 << " new addr: " << format("%p", Addr)
522 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
523 << " Allocate: " << Allocate << "\n");
524 Obj.updateSectionAddress(Section, (uint64_t)Addr);
526 // Even if we didn't load the section, we need to record an entry for it
527 // to handle later processing (and by 'handle' I mean don't do anything
528 // with these sections).
531 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
532 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
533 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
534 << " Allocate: " << Allocate << "\n");
537 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
540 Checker->registerSection(Obj.getImageName(), SectionID);
545 unsigned RuntimeDyldImpl::findOrEmitSection(ObjectImage &Obj,
546 const SectionRef &Section,
548 ObjSectionToIDMap &LocalSections) {
550 unsigned SectionID = 0;
551 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
552 if (i != LocalSections.end())
553 SectionID = i->second;
555 SectionID = emitSection(Obj, Section, IsCode);
556 LocalSections[Section] = SectionID;
561 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
562 unsigned SectionID) {
563 Relocations[SectionID].push_back(RE);
566 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
567 StringRef SymbolName) {
568 // Relocation by symbol. If the symbol is found in the global symbol table,
569 // create an appropriate section relocation. Otherwise, add it to
570 // ExternalSymbolRelocations.
571 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
572 if (Loc == GlobalSymbolTable.end()) {
573 ExternalSymbolRelocations[SymbolName].push_back(RE);
575 // Copy the RE since we want to modify its addend.
576 RelocationEntry RECopy = RE;
577 RECopy.Addend += Loc->second.second;
578 Relocations[Loc->second.first].push_back(RECopy);
582 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
583 unsigned AbiVariant) {
584 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
585 // This stub has to be able to access the full address space,
586 // since symbol lookup won't necessarily find a handy, in-range,
587 // PLT stub for functions which could be anywhere.
588 // Stub can use ip0 (== x16) to calculate address
589 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
590 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
591 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
592 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
593 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
596 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
597 // TODO: There is only ARM far stub now. We should add the Thumb stub,
598 // and stubs for branches Thumb - ARM and ARM - Thumb.
599 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
601 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
602 // 0: 3c190000 lui t9,%hi(addr).
603 // 4: 27390000 addiu t9,t9,%lo(addr).
604 // 8: 03200008 jr t9.
606 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
607 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
609 writeBytesUnaligned(LuiT9Instr, Addr, 4);
610 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
611 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
612 writeBytesUnaligned(NopInstr, Addr+12, 4);
614 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
615 // Depending on which version of the ELF ABI is in use, we need to
616 // generate one of two variants of the stub. They both start with
617 // the same sequence to load the target address into r12.
618 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
619 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
620 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
621 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
622 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
623 if (AbiVariant == 2) {
624 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
625 // The address is already in r12 as required by the ABI. Branch to it.
626 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
627 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
628 writeInt32BE(Addr+28, 0x4E800420); // bctr
630 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
631 // Load the function address on r11 and sets it to control register. Also
632 // loads the function TOC in r2 and environment pointer to r11.
633 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
634 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
635 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
636 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
637 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
638 writeInt32BE(Addr+40, 0x4E800420); // bctr
641 } else if (Arch == Triple::systemz) {
642 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
643 writeInt16BE(Addr+2, 0x0000);
644 writeInt16BE(Addr+4, 0x0004);
645 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
646 // 8-byte address stored at Addr + 8
648 } else if (Arch == Triple::x86_64) {
650 *(Addr+1) = 0x25; // rip
651 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
652 } else if (Arch == Triple::x86) {
653 *Addr = 0xE9; // 32-bit pc-relative jump.
658 // Assign an address to a symbol name and resolve all the relocations
659 // associated with it.
660 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
662 // The address to use for relocation resolution is not
663 // the address of the local section buffer. We must be doing
664 // a remote execution environment of some sort. Relocations can't
665 // be applied until all the sections have been moved. The client must
666 // trigger this with a call to MCJIT::finalize() or
667 // RuntimeDyld::resolveRelocations().
669 // Addr is a uint64_t because we can't assume the pointer width
670 // of the target is the same as that of the host. Just use a generic
671 // "big enough" type.
672 DEBUG(dbgs() << "Reassigning address for section "
673 << SectionID << " (" << Sections[SectionID].Name << "): "
674 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
675 << format("0x%016" PRIx64, Addr) << "\n");
676 Sections[SectionID].LoadAddress = Addr;
679 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
681 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
682 const RelocationEntry &RE = Relocs[i];
683 // Ignore relocations for sections that were not loaded
684 if (Sections[RE.SectionID].Address == nullptr)
686 resolveRelocation(RE, Value);
690 void RuntimeDyldImpl::resolveExternalSymbols() {
691 while (!ExternalSymbolRelocations.empty()) {
692 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
694 StringRef Name = i->first();
695 if (Name.size() == 0) {
696 // This is an absolute symbol, use an address of zero.
697 DEBUG(dbgs() << "Resolving absolute relocations."
699 RelocationList &Relocs = i->second;
700 resolveRelocationList(Relocs, 0);
703 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(Name);
704 if (Loc == GlobalSymbolTable.end()) {
705 // This is an external symbol, try to get its address from
707 Addr = MemMgr->getSymbolAddress(Name.data());
708 // The call to getSymbolAddress may have caused additional modules to
709 // be loaded, which may have added new entries to the
710 // ExternalSymbolRelocations map. Consquently, we need to update our
711 // iterator. This is also why retrieval of the relocation list
712 // associated with this symbol is deferred until below this point.
713 // New entries may have been added to the relocation list.
714 i = ExternalSymbolRelocations.find(Name);
716 // We found the symbol in our global table. It was probably in a
717 // Module that we loaded previously.
718 SymbolLoc SymLoc = Loc->second;
719 Addr = getSectionLoadAddress(SymLoc.first) + SymLoc.second;
722 // FIXME: Implement error handling that doesn't kill the host program!
724 report_fatal_error("Program used external function '" + Name +
725 "' which could not be resolved!");
727 updateGOTEntries(Name, Addr);
728 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
729 << format("0x%lx", Addr) << "\n");
730 // This list may have been updated when we called getSymbolAddress, so
731 // don't change this code to get the list earlier.
732 RelocationList &Relocs = i->second;
733 resolveRelocationList(Relocs, Addr);
736 ExternalSymbolRelocations.erase(i);
740 //===----------------------------------------------------------------------===//
741 // RuntimeDyld class implementation
742 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
743 // FIXME: There's a potential issue lurking here if a single instance of
744 // RuntimeDyld is used to load multiple objects. The current implementation
745 // associates a single memory manager with a RuntimeDyld instance. Even
746 // though the public class spawns a new 'impl' instance for each load,
747 // they share a single memory manager. This can become a problem when page
748 // permissions are applied.
751 ProcessAllSections = false;
755 RuntimeDyld::~RuntimeDyld() {}
757 static std::unique_ptr<RuntimeDyldELF>
758 createRuntimeDyldELF(RTDyldMemoryManager *MM, bool ProcessAllSections,
759 RuntimeDyldCheckerImpl *Checker) {
760 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM));
761 Dyld->setProcessAllSections(ProcessAllSections);
762 Dyld->setRuntimeDyldChecker(Checker);
766 static std::unique_ptr<RuntimeDyldMachO>
767 createRuntimeDyldMachO(Triple::ArchType Arch, RTDyldMemoryManager *MM,
768 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
769 std::unique_ptr<RuntimeDyldMachO> Dyld(RuntimeDyldMachO::create(Arch, MM));
770 Dyld->setProcessAllSections(ProcessAllSections);
771 Dyld->setRuntimeDyldChecker(Checker);
775 std::unique_ptr<ObjectImage>
776 RuntimeDyld::loadObject(std::unique_ptr<ObjectFile> InputObject) {
777 std::unique_ptr<ObjectImage> InputImage;
779 ObjectFile &Obj = *InputObject;
781 if (InputObject->isELF()) {
782 InputImage.reset(RuntimeDyldELF::createObjectImageFromFile(std::move(InputObject)));
784 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
785 } else if (InputObject->isMachO()) {
786 InputImage.reset(RuntimeDyldMachO::createObjectImageFromFile(std::move(InputObject)));
788 Dyld = createRuntimeDyldMachO(
789 static_cast<Triple::ArchType>(InputImage->getArch()), MM,
790 ProcessAllSections, Checker);
792 report_fatal_error("Incompatible object format!");
794 if (!Dyld->isCompatibleFile(&Obj))
795 report_fatal_error("Incompatible object format!");
797 return Dyld->loadObject(std::move(InputImage));
800 std::unique_ptr<ObjectImage>
801 RuntimeDyld::loadObject(std::unique_ptr<ObjectBuffer> InputBuffer) {
802 std::unique_ptr<ObjectImage> InputImage;
803 sys::fs::file_magic Type = sys::fs::identify_magic(InputBuffer->getBuffer());
804 auto *InputBufferPtr = InputBuffer.get();
807 case sys::fs::file_magic::elf_relocatable:
808 case sys::fs::file_magic::elf_executable:
809 case sys::fs::file_magic::elf_shared_object:
810 case sys::fs::file_magic::elf_core:
811 InputImage = RuntimeDyldELF::createObjectImage(std::move(InputBuffer));
813 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
815 case sys::fs::file_magic::macho_object:
816 case sys::fs::file_magic::macho_executable:
817 case sys::fs::file_magic::macho_fixed_virtual_memory_shared_lib:
818 case sys::fs::file_magic::macho_core:
819 case sys::fs::file_magic::macho_preload_executable:
820 case sys::fs::file_magic::macho_dynamically_linked_shared_lib:
821 case sys::fs::file_magic::macho_dynamic_linker:
822 case sys::fs::file_magic::macho_bundle:
823 case sys::fs::file_magic::macho_dynamically_linked_shared_lib_stub:
824 case sys::fs::file_magic::macho_dsym_companion:
825 InputImage = RuntimeDyldMachO::createObjectImage(std::move(InputBuffer));
827 Dyld = createRuntimeDyldMachO(
828 static_cast<Triple::ArchType>(InputImage->getArch()), MM,
829 ProcessAllSections, Checker);
831 case sys::fs::file_magic::unknown:
832 case sys::fs::file_magic::bitcode:
833 case sys::fs::file_magic::archive:
834 case sys::fs::file_magic::coff_object:
835 case sys::fs::file_magic::coff_import_library:
836 case sys::fs::file_magic::pecoff_executable:
837 case sys::fs::file_magic::macho_universal_binary:
838 case sys::fs::file_magic::windows_resource:
839 report_fatal_error("Incompatible object format!");
842 if (!Dyld->isCompatibleFormat(InputBufferPtr))
843 report_fatal_error("Incompatible object format!");
845 return Dyld->loadObject(std::move(InputImage));
848 void *RuntimeDyld::getSymbolAddress(StringRef Name) const {
851 return Dyld->getSymbolAddress(Name);
854 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) const {
857 return Dyld->getSymbolLoadAddress(Name);
860 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
862 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
863 Dyld->reassignSectionAddress(SectionID, Addr);
866 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
867 uint64_t TargetAddress) {
868 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
871 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
873 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
875 void RuntimeDyld::registerEHFrames() {
877 Dyld->registerEHFrames();
880 void RuntimeDyld::deregisterEHFrames() {
882 Dyld->deregisterEHFrames();
885 } // end namespace llvm