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() << "\tType: " << SymType << " Name: " << Name
204 << " SID: " << SectionID << " Offset: "
205 << format("%p", (uintptr_t)SectOffset)
206 << " flags: " << Flags << "\n");
207 SymbolInfo::Visibility Vis =
208 (Flags & SymbolRef::SF_Exported) ?
209 SymbolInfo::Default : SymbolInfo::Hidden;
210 GlobalSymbolTable[Name] = SymbolInfo(SectionID, SectOffset, Vis);
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.section_begin(), SE = Obj.section_end();
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)
234 bool IsCode = RelocatedSection->isText();
236 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
237 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
240 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
242 // If there is an attached checker, notify it about the stubs for this
243 // section so that they can be verified.
245 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
248 // Give the subclasses a chance to tie-up any loose ends.
249 finalizeLoad(Obj, LocalSections);
251 unsigned SectionsAddedEndIdx = Sections.size();
253 return std::make_pair(SectionsAddedBeginIdx, SectionsAddedEndIdx);
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 static bool isRequiredForExecution(const SectionRef &Section) {
272 const ObjectFile *Obj = Section.getObject();
273 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
274 return ELFObj->getSectionFlags(Section) & ELF::SHF_ALLOC;
275 assert(isa<MachOObjectFile>(Obj));
279 static bool isReadOnlyData(const SectionRef &Section) {
280 const ObjectFile *Obj = Section.getObject();
281 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
282 return !(ELFObj->getSectionFlags(Section) &
283 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
284 assert(isa<MachOObjectFile>(Obj));
288 static bool isZeroInit(const SectionRef &Section) {
289 const ObjectFile *Obj = Section.getObject();
290 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
291 return ELFObj->getSectionType(Section) == ELF::SHT_NOBITS;
293 auto *MachO = cast<MachOObjectFile>(Obj);
294 unsigned SectionType = MachO->getSectionType(Section);
295 return SectionType == MachO::S_ZEROFILL ||
296 SectionType == MachO::S_GB_ZEROFILL;
299 // Compute an upper bound of the memory size that is required to load all
301 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
303 uint64_t &DataSizeRO,
304 uint64_t &DataSizeRW) {
305 // Compute the size of all sections required for execution
306 std::vector<uint64_t> CodeSectionSizes;
307 std::vector<uint64_t> ROSectionSizes;
308 std::vector<uint64_t> RWSectionSizes;
309 uint64_t MaxAlignment = sizeof(void *);
311 // Collect sizes of all sections to be loaded;
312 // also determine the max alignment of all sections
313 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
315 const SectionRef &Section = *SI;
317 bool IsRequired = isRequiredForExecution(Section);
319 // Consider only the sections that are required to be loaded for execution
322 uint64_t DataSize = Section.getSize();
323 uint64_t Alignment64 = Section.getAlignment();
324 bool IsCode = Section.isText();
325 bool IsReadOnly = isReadOnlyData(Section);
326 Check(Section.getName(Name));
327 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
329 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
330 uint64_t SectionSize = DataSize + StubBufSize;
332 // The .eh_frame section (at least on Linux) needs an extra four bytes
334 // with zeroes added at the end. For MachO objects, this section has a
335 // slightly different name, so this won't have any effect for MachO
337 if (Name == ".eh_frame")
340 if (SectionSize > 0) {
341 // save the total size of the section
343 CodeSectionSizes.push_back(SectionSize);
344 } else if (IsReadOnly) {
345 ROSectionSizes.push_back(SectionSize);
347 RWSectionSizes.push_back(SectionSize);
349 // update the max alignment
350 if (Alignment > MaxAlignment) {
351 MaxAlignment = Alignment;
357 // Compute the size of all common symbols
358 uint64_t CommonSize = 0;
359 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
361 uint32_t Flags = I->getFlags();
362 if (Flags & SymbolRef::SF_Common) {
363 // Add the common symbols to a list. We'll allocate them all below.
365 Check(I->getSize(Size));
369 if (CommonSize != 0) {
370 RWSectionSizes.push_back(CommonSize);
373 // Compute the required allocation space for each different type of sections
374 // (code, read-only data, read-write data) assuming that all sections are
375 // allocated with the max alignment. Note that we cannot compute with the
376 // individual alignments of the sections, because then the required size
377 // depends on the order, in which the sections are allocated.
378 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
379 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
380 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
383 // compute stub buffer size for the given section
384 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
385 const SectionRef &Section) {
386 unsigned StubSize = getMaxStubSize();
390 // FIXME: this is an inefficient way to handle this. We should computed the
391 // necessary section allocation size in loadObject by walking all the sections
393 unsigned StubBufSize = 0;
394 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
396 section_iterator RelSecI = SI->getRelocatedSection();
397 if (!(RelSecI == Section))
400 for (const RelocationRef &Reloc : SI->relocations()) {
402 StubBufSize += StubSize;
406 // Get section data size and alignment
407 uint64_t DataSize = Section.getSize();
408 uint64_t Alignment64 = Section.getAlignment();
410 // Add stubbuf size alignment
411 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
412 unsigned StubAlignment = getStubAlignment();
413 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
414 if (StubAlignment > EndAlignment)
415 StubBufSize += StubAlignment - EndAlignment;
419 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
420 unsigned Size) const {
422 if (IsTargetLittleEndian) {
425 Result = (Result << 8) | *Src--;
428 Result = (Result << 8) | *Src++;
433 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
434 unsigned Size) const {
435 if (IsTargetLittleEndian) {
437 *Dst++ = Value & 0xFF;
443 *Dst-- = Value & 0xFF;
449 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
450 const CommonSymbolMap &CommonSymbols,
452 RTDyldSymbolTable &SymbolTable) {
453 // Allocate memory for the section
454 unsigned SectionID = Sections.size();
455 uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, sizeof(void *),
456 SectionID, StringRef(), false);
458 report_fatal_error("Unable to allocate memory for common symbols!");
460 Sections.push_back(SectionEntry("<common symbols>", Addr, TotalSize, 0));
461 memset(Addr, 0, TotalSize);
463 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
464 << format("%p", Addr) << " DataSize: " << TotalSize << "\n");
466 // Assign the address of each symbol
467 for (CommonSymbolMap::const_iterator it = CommonSymbols.begin(),
468 itEnd = CommonSymbols.end(); it != itEnd; ++it) {
469 uint64_t Size = it->second.first;
470 uint64_t Align = it->second.second;
472 it->first.getName(Name);
474 // This symbol has an alignment requirement.
475 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
477 Offset += AlignOffset;
478 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
479 << format("%p\n", Addr));
481 uint32_t Flags = it->first.getFlags();
482 SymbolInfo::Visibility Vis =
483 (Flags & SymbolRef::SF_Exported) ?
484 SymbolInfo::Default : SymbolInfo::Hidden;
485 SymbolTable[Name.data()] = SymbolInfo(SectionID, Offset, Vis);
491 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
492 const SectionRef &Section, bool IsCode) {
495 Check(Section.getContents(data));
496 uint64_t Alignment64 = Section.getAlignment();
498 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
499 unsigned PaddingSize = 0;
500 unsigned StubBufSize = 0;
502 bool IsRequired = isRequiredForExecution(Section);
503 bool IsVirtual = Section.isVirtual();
504 bool IsZeroInit = isZeroInit(Section);
505 bool IsReadOnly = isReadOnlyData(Section);
506 uint64_t DataSize = Section.getSize();
507 Check(Section.getName(Name));
509 StubBufSize = computeSectionStubBufSize(Obj, Section);
511 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
512 // with zeroes added at the end. For MachO objects, this section has a
513 // slightly different name, so this won't have any effect for MachO objects.
514 if (Name == ".eh_frame")
518 unsigned SectionID = Sections.size();
520 const char *pData = nullptr;
522 // Some sections, such as debug info, don't need to be loaded for execution.
523 // Leave those where they are.
525 Allocate = DataSize + PaddingSize + StubBufSize;
526 Addr = IsCode ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID,
528 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID,
531 report_fatal_error("Unable to allocate section memory!");
533 // Virtual sections have no data in the object image, so leave pData = 0
537 // Zero-initialize or copy the data from the image
538 if (IsZeroInit || IsVirtual)
539 memset(Addr, 0, DataSize);
541 memcpy(Addr, pData, DataSize);
543 // Fill in any extra bytes we allocated for padding
544 if (PaddingSize != 0) {
545 memset(Addr + DataSize, 0, PaddingSize);
546 // Update the DataSize variable so that the stub offset is set correctly.
547 DataSize += PaddingSize;
550 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
551 << " obj addr: " << format("%p", pData)
552 << " new addr: " << format("%p", Addr)
553 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
554 << " Allocate: " << Allocate << "\n");
556 // Even if we didn't load the section, we need to record an entry for it
557 // to handle later processing (and by 'handle' I mean don't do anything
558 // with these sections).
561 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
562 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
563 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
564 << " Allocate: " << Allocate << "\n");
567 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
570 Checker->registerSection(Obj.getFileName(), SectionID);
575 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
576 const SectionRef &Section,
578 ObjSectionToIDMap &LocalSections) {
580 unsigned SectionID = 0;
581 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
582 if (i != LocalSections.end())
583 SectionID = i->second;
585 SectionID = emitSection(Obj, Section, IsCode);
586 LocalSections[Section] = SectionID;
591 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
592 unsigned SectionID) {
593 Relocations[SectionID].push_back(RE);
596 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
597 StringRef SymbolName) {
598 // Relocation by symbol. If the symbol is found in the global symbol table,
599 // create an appropriate section relocation. Otherwise, add it to
600 // ExternalSymbolRelocations.
601 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
602 if (Loc == GlobalSymbolTable.end()) {
603 ExternalSymbolRelocations[SymbolName].push_back(RE);
605 // Copy the RE since we want to modify its addend.
606 RelocationEntry RECopy = RE;
607 const auto &SymInfo = Loc->second;
608 RECopy.Addend += SymInfo.getOffset();
609 Relocations[SymInfo.getSectionID()].push_back(RECopy);
613 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
614 unsigned AbiVariant) {
615 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
616 // This stub has to be able to access the full address space,
617 // since symbol lookup won't necessarily find a handy, in-range,
618 // PLT stub for functions which could be anywhere.
619 // Stub can use ip0 (== x16) to calculate address
620 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
621 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
622 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
623 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
624 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
627 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
628 // TODO: There is only ARM far stub now. We should add the Thumb stub,
629 // and stubs for branches Thumb - ARM and ARM - Thumb.
630 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
632 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
633 // 0: 3c190000 lui t9,%hi(addr).
634 // 4: 27390000 addiu t9,t9,%lo(addr).
635 // 8: 03200008 jr t9.
637 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
638 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
640 writeBytesUnaligned(LuiT9Instr, Addr, 4);
641 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
642 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
643 writeBytesUnaligned(NopInstr, Addr+12, 4);
645 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
646 // Depending on which version of the ELF ABI is in use, we need to
647 // generate one of two variants of the stub. They both start with
648 // the same sequence to load the target address into r12.
649 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
650 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
651 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
652 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
653 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
654 if (AbiVariant == 2) {
655 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
656 // The address is already in r12 as required by the ABI. Branch to it.
657 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
658 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
659 writeInt32BE(Addr+28, 0x4E800420); // bctr
661 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
662 // Load the function address on r11 and sets it to control register. Also
663 // loads the function TOC in r2 and environment pointer to r11.
664 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
665 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
666 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
667 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
668 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
669 writeInt32BE(Addr+40, 0x4E800420); // bctr
672 } else if (Arch == Triple::systemz) {
673 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
674 writeInt16BE(Addr+2, 0x0000);
675 writeInt16BE(Addr+4, 0x0004);
676 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
677 // 8-byte address stored at Addr + 8
679 } else if (Arch == Triple::x86_64) {
681 *(Addr+1) = 0x25; // rip
682 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
683 } else if (Arch == Triple::x86) {
684 *Addr = 0xE9; // 32-bit pc-relative jump.
689 // Assign an address to a symbol name and resolve all the relocations
690 // associated with it.
691 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
693 // The address to use for relocation resolution is not
694 // the address of the local section buffer. We must be doing
695 // a remote execution environment of some sort. Relocations can't
696 // be applied until all the sections have been moved. The client must
697 // trigger this with a call to MCJIT::finalize() or
698 // RuntimeDyld::resolveRelocations().
700 // Addr is a uint64_t because we can't assume the pointer width
701 // of the target is the same as that of the host. Just use a generic
702 // "big enough" type.
703 DEBUG(dbgs() << "Reassigning address for section "
704 << SectionID << " (" << Sections[SectionID].Name << "): "
705 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
706 << format("0x%016" PRIx64, Addr) << "\n");
707 Sections[SectionID].LoadAddress = Addr;
710 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
712 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
713 const RelocationEntry &RE = Relocs[i];
714 // Ignore relocations for sections that were not loaded
715 if (Sections[RE.SectionID].Address == nullptr)
717 resolveRelocation(RE, Value);
721 void RuntimeDyldImpl::resolveExternalSymbols() {
722 while (!ExternalSymbolRelocations.empty()) {
723 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
725 StringRef Name = i->first();
726 if (Name.size() == 0) {
727 // This is an absolute symbol, use an address of zero.
728 DEBUG(dbgs() << "Resolving absolute relocations."
730 RelocationList &Relocs = i->second;
731 resolveRelocationList(Relocs, 0);
734 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
735 if (Loc == GlobalSymbolTable.end()) {
736 // This is an external symbol, try to get its address from
738 Addr = MemMgr->getSymbolAddress(Name.data());
739 // The call to getSymbolAddress may have caused additional modules to
740 // be loaded, which may have added new entries to the
741 // ExternalSymbolRelocations map. Consquently, we need to update our
742 // iterator. This is also why retrieval of the relocation list
743 // associated with this symbol is deferred until below this point.
744 // New entries may have been added to the relocation list.
745 i = ExternalSymbolRelocations.find(Name);
747 // We found the symbol in our global table. It was probably in a
748 // Module that we loaded previously.
749 const auto &SymInfo = Loc->second;
750 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
754 // FIXME: Implement error handling that doesn't kill the host program!
756 report_fatal_error("Program used external function '" + Name +
757 "' which could not be resolved!");
759 updateGOTEntries(Name, Addr);
760 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
761 << format("0x%lx", Addr) << "\n");
762 // This list may have been updated when we called getSymbolAddress, so
763 // don't change this code to get the list earlier.
764 RelocationList &Relocs = i->second;
765 resolveRelocationList(Relocs, Addr);
768 ExternalSymbolRelocations.erase(i);
772 //===----------------------------------------------------------------------===//
773 // RuntimeDyld class implementation
775 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
776 StringRef SectionName) const {
777 for (unsigned I = BeginIdx; I != EndIdx; ++I)
778 if (RTDyld.Sections[I].Name == SectionName)
779 return RTDyld.Sections[I].LoadAddress;
784 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
785 // FIXME: There's a potential issue lurking here if a single instance of
786 // RuntimeDyld is used to load multiple objects. The current implementation
787 // associates a single memory manager with a RuntimeDyld instance. Even
788 // though the public class spawns a new 'impl' instance for each load,
789 // they share a single memory manager. This can become a problem when page
790 // permissions are applied.
793 ProcessAllSections = false;
797 RuntimeDyld::~RuntimeDyld() {}
799 static std::unique_ptr<RuntimeDyldELF>
800 createRuntimeDyldELF(RTDyldMemoryManager *MM, bool ProcessAllSections,
801 RuntimeDyldCheckerImpl *Checker) {
802 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM));
803 Dyld->setProcessAllSections(ProcessAllSections);
804 Dyld->setRuntimeDyldChecker(Checker);
808 static std::unique_ptr<RuntimeDyldMachO>
809 createRuntimeDyldMachO(Triple::ArchType Arch, RTDyldMemoryManager *MM,
810 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
811 std::unique_ptr<RuntimeDyldMachO> Dyld(RuntimeDyldMachO::create(Arch, MM));
812 Dyld->setProcessAllSections(ProcessAllSections);
813 Dyld->setRuntimeDyldChecker(Checker);
817 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
818 RuntimeDyld::loadObject(const ObjectFile &Obj) {
821 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
822 else if (Obj.isMachO())
823 Dyld = createRuntimeDyldMachO(
824 static_cast<Triple::ArchType>(Obj.getArch()), MM,
825 ProcessAllSections, Checker);
827 report_fatal_error("Incompatible object format!");
830 if (!Dyld->isCompatibleFile(Obj))
831 report_fatal_error("Incompatible object format!");
833 return Dyld->loadObject(Obj);
836 void *RuntimeDyld::getSymbolAddress(StringRef Name) const {
839 return Dyld->getSymbolAddress(Name);
842 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) const {
845 return Dyld->getSymbolLoadAddress(Name);
848 uint64_t RuntimeDyld::getExportedSymbolLoadAddress(StringRef Name) const {
851 return Dyld->getExportedSymbolLoadAddress(Name);
854 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
856 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
857 Dyld->reassignSectionAddress(SectionID, Addr);
860 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
861 uint64_t TargetAddress) {
862 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
865 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
867 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
869 void RuntimeDyld::registerEHFrames() {
871 Dyld->registerEHFrames();
874 void RuntimeDyld::deregisterEHFrames() {
876 Dyld->deregisterEHFrames();
879 } // end namespace llvm