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 "RuntimeDyldCOFF.h"
17 #include "RuntimeDyldELF.h"
18 #include "RuntimeDyldImpl.h"
19 #include "RuntimeDyldMachO.h"
20 #include "llvm/Object/ELFObjectFile.h"
21 #include "llvm/Object/COFF.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 LoadedObjectInfo's vtables to this file.
34 void RuntimeDyld::LoadedObjectInfo::anchor() {}
38 void RuntimeDyldImpl::registerEHFrames() {}
40 void RuntimeDyldImpl::deregisterEHFrames() {}
43 static void dumpSectionMemory(const SectionEntry &S, StringRef State) {
44 dbgs() << "----- Contents of section " << S.Name << " " << State << " -----";
46 if (S.Address == nullptr) {
47 dbgs() << "\n <section not emitted>\n";
51 const unsigned ColsPerRow = 16;
53 uint8_t *DataAddr = S.Address;
54 uint64_t LoadAddr = S.LoadAddress;
56 unsigned StartPadding = LoadAddr & (ColsPerRow - 1);
57 unsigned BytesRemaining = S.Size;
60 dbgs() << "\n" << format("0x%016" PRIx64,
61 LoadAddr & ~(uint64_t)(ColsPerRow - 1)) << ":";
62 while (StartPadding--)
66 while (BytesRemaining > 0) {
67 if ((LoadAddr & (ColsPerRow - 1)) == 0)
68 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr) << ":";
70 dbgs() << " " << format("%02x", *DataAddr);
81 // Resolve the relocations for all symbols we currently know about.
82 void RuntimeDyldImpl::resolveRelocations() {
83 MutexGuard locked(lock);
85 // First, resolve relocations associated with external symbols.
86 resolveExternalSymbols();
88 // Just iterate over the sections we have and resolve all the relocations
89 // in them. Gross overkill, but it gets the job done.
90 for (int i = 0, e = Sections.size(); i != e; ++i) {
91 // The Section here (Sections[i]) refers to the section in which the
92 // symbol for the relocation is located. The SectionID in the relocation
93 // entry provides the section to which the relocation will be applied.
94 uint64_t Addr = Sections[i].LoadAddress;
95 DEBUG(dbgs() << "Resolving relocations Section #" << i << "\t"
96 << format("%p", (uintptr_t)Addr) << "\n");
97 DEBUG(dumpSectionMemory(Sections[i], "before relocations"));
98 resolveRelocationList(Relocations[i], Addr);
99 DEBUG(dumpSectionMemory(Sections[i], "after relocations"));
100 Relocations.erase(i);
104 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
105 uint64_t TargetAddress) {
106 MutexGuard locked(lock);
107 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
108 if (Sections[i].Address == LocalAddress) {
109 reassignSectionAddress(i, TargetAddress);
113 llvm_unreachable("Attempting to remap address of unknown section!");
116 static std::error_code getOffset(const SymbolRef &Sym, uint64_t &Result) {
118 if (std::error_code EC = Sym.getAddress(Address))
121 if (Address == UnknownAddress) {
122 Result = UnknownAddress;
123 return std::error_code();
126 const ObjectFile *Obj = Sym.getObject();
127 section_iterator SecI(Obj->section_begin());
128 if (std::error_code EC = Sym.getSection(SecI))
131 if (SecI == Obj->section_end()) {
132 Result = UnknownAddress;
133 return std::error_code();
136 uint64_t SectionAddress = SecI->getAddress();
137 Result = Address - SectionAddress;
138 return std::error_code();
141 std::pair<unsigned, unsigned>
142 RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
143 MutexGuard locked(lock);
145 // Grab the first Section ID. We'll use this later to construct the underlying
146 // range for the returned LoadedObjectInfo.
147 unsigned SectionsAddedBeginIdx = Sections.size();
149 // Save information about our target
150 Arch = (Triple::ArchType)Obj.getArch();
151 IsTargetLittleEndian = Obj.isLittleEndian();
154 // Compute the memory size required to load all sections to be loaded
155 // and pass this information to the memory manager
156 if (MemMgr.needsToReserveAllocationSpace()) {
157 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
158 computeTotalAllocSize(Obj, CodeSize, DataSizeRO, DataSizeRW);
159 MemMgr.reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
162 // Used sections from the object file
163 ObjSectionToIDMap LocalSections;
165 // Common symbols requiring allocation, with their sizes and alignments
166 CommonSymbolList CommonSymbols;
169 DEBUG(dbgs() << "Parse symbols:\n");
170 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
172 uint32_t Flags = I->getFlags();
174 bool IsCommon = Flags & SymbolRef::SF_Common;
176 CommonSymbols.push_back(*I);
178 object::SymbolRef::Type SymType;
179 Check(I->getType(SymType));
181 if (SymType == object::SymbolRef::ST_Function ||
182 SymType == object::SymbolRef::ST_Data ||
183 SymType == object::SymbolRef::ST_Unknown) {
187 Check(I->getName(Name));
188 Check(getOffset(*I, SectOffset));
189 section_iterator SI = Obj.section_end();
190 Check(I->getSection(SI));
191 if (SI == Obj.section_end())
193 StringRef SectionData;
194 Check(SI->getContents(SectionData));
195 bool IsCode = SI->isText();
197 findOrEmitSection(Obj, *SI, IsCode, LocalSections);
198 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
199 << " SID: " << SectionID << " Offset: "
200 << format("%p", (uintptr_t)SectOffset)
201 << " flags: " << Flags << "\n");
202 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
203 if (Flags & SymbolRef::SF_Weak)
204 RTDyldSymFlags |= JITSymbolFlags::Weak;
205 if (Flags & SymbolRef::SF_Exported)
206 RTDyldSymFlags |= JITSymbolFlags::Exported;
207 GlobalSymbolTable[Name] =
208 SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
213 // Allocate common symbols
214 emitCommonSymbols(Obj, CommonSymbols);
216 // Parse and process relocations
217 DEBUG(dbgs() << "Parse relocations:\n");
218 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
220 unsigned SectionID = 0;
222 section_iterator RelocatedSection = SI->getRelocatedSection();
224 if (RelocatedSection == SE)
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 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) {
275 const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
276 // Avoid loading zero-sized COFF sections.
277 // In PE files, VirtualSize gives the section size, and SizeOfRawData
278 // may be zero for sections with content. In Obj files, SizeOfRawData
279 // gives the section size, and VirtualSize is always zero. Hence
280 // the need to check for both cases below.
281 bool HasContent = (CoffSection->VirtualSize > 0)
282 || (CoffSection->SizeOfRawData > 0);
283 bool IsDiscardable = CoffSection->Characteristics &
284 (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
285 return HasContent && !IsDiscardable;
288 assert(isa<MachOObjectFile>(Obj));
292 static bool isReadOnlyData(const SectionRef &Section) {
293 const ObjectFile *Obj = Section.getObject();
294 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
295 return !(ELFObj->getSectionFlags(Section) &
296 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
297 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
298 return ((COFFObj->getCOFFSection(Section)->Characteristics &
299 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
300 | COFF::IMAGE_SCN_MEM_READ
301 | COFF::IMAGE_SCN_MEM_WRITE))
303 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
304 | COFF::IMAGE_SCN_MEM_READ));
306 assert(isa<MachOObjectFile>(Obj));
310 static bool isZeroInit(const SectionRef &Section) {
311 const ObjectFile *Obj = Section.getObject();
312 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
313 return ELFObj->getSectionType(Section) == ELF::SHT_NOBITS;
314 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
315 return COFFObj->getCOFFSection(Section)->Characteristics &
316 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
318 auto *MachO = cast<MachOObjectFile>(Obj);
319 unsigned SectionType = MachO->getSectionType(Section);
320 return SectionType == MachO::S_ZEROFILL ||
321 SectionType == MachO::S_GB_ZEROFILL;
324 // Compute an upper bound of the memory size that is required to load all
326 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
328 uint64_t &DataSizeRO,
329 uint64_t &DataSizeRW) {
330 // Compute the size of all sections required for execution
331 std::vector<uint64_t> CodeSectionSizes;
332 std::vector<uint64_t> ROSectionSizes;
333 std::vector<uint64_t> RWSectionSizes;
334 uint64_t MaxAlignment = sizeof(void *);
336 // Collect sizes of all sections to be loaded;
337 // also determine the max alignment of all sections
338 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
340 const SectionRef &Section = *SI;
342 bool IsRequired = isRequiredForExecution(Section);
344 // Consider only the sections that are required to be loaded for execution
347 uint64_t DataSize = Section.getSize();
348 uint64_t Alignment64 = Section.getAlignment();
349 bool IsCode = Section.isText();
350 bool IsReadOnly = isReadOnlyData(Section);
351 Check(Section.getName(Name));
352 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
354 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
355 uint64_t SectionSize = DataSize + StubBufSize;
357 // The .eh_frame section (at least on Linux) needs an extra four bytes
359 // with zeroes added at the end. For MachO objects, this section has a
360 // slightly different name, so this won't have any effect for MachO
362 if (Name == ".eh_frame")
369 CodeSectionSizes.push_back(SectionSize);
370 } else if (IsReadOnly) {
371 ROSectionSizes.push_back(SectionSize);
373 RWSectionSizes.push_back(SectionSize);
376 // update the max alignment
377 if (Alignment > MaxAlignment) {
378 MaxAlignment = Alignment;
383 // Compute the size of all common symbols
384 uint64_t CommonSize = 0;
385 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
387 uint32_t Flags = I->getFlags();
388 if (Flags & SymbolRef::SF_Common) {
389 // Add the common symbols to a list. We'll allocate them all below.
390 uint64_t Size = I->getCommonSize();
394 if (CommonSize != 0) {
395 RWSectionSizes.push_back(CommonSize);
398 // Compute the required allocation space for each different type of sections
399 // (code, read-only data, read-write data) assuming that all sections are
400 // allocated with the max alignment. Note that we cannot compute with the
401 // individual alignments of the sections, because then the required size
402 // depends on the order, in which the sections are allocated.
403 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
404 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
405 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
408 // compute stub buffer size for the given section
409 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
410 const SectionRef &Section) {
411 unsigned StubSize = getMaxStubSize();
415 // FIXME: this is an inefficient way to handle this. We should computed the
416 // necessary section allocation size in loadObject by walking all the sections
418 unsigned StubBufSize = 0;
419 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
421 section_iterator RelSecI = SI->getRelocatedSection();
422 if (!(RelSecI == Section))
425 for (const RelocationRef &Reloc : SI->relocations()) {
427 StubBufSize += StubSize;
431 // Get section data size and alignment
432 uint64_t DataSize = Section.getSize();
433 uint64_t Alignment64 = Section.getAlignment();
435 // Add stubbuf size alignment
436 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
437 unsigned StubAlignment = getStubAlignment();
438 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
439 if (StubAlignment > EndAlignment)
440 StubBufSize += StubAlignment - EndAlignment;
444 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
445 unsigned Size) const {
447 if (IsTargetLittleEndian) {
450 Result = (Result << 8) | *Src--;
453 Result = (Result << 8) | *Src++;
458 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
459 unsigned Size) const {
460 if (IsTargetLittleEndian) {
462 *Dst++ = Value & 0xFF;
468 *Dst-- = Value & 0xFF;
474 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
475 CommonSymbolList &CommonSymbols) {
476 if (CommonSymbols.empty())
479 uint64_t CommonSize = 0;
480 CommonSymbolList SymbolsToAllocate;
482 DEBUG(dbgs() << "Processing common symbols...\n");
484 for (const auto &Sym : CommonSymbols) {
486 Check(Sym.getName(Name));
488 // Skip common symbols already elsewhere.
489 if (GlobalSymbolTable.count(Name) ||
490 Resolver.findSymbolInLogicalDylib(Name)) {
491 DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name
496 uint32_t Align = Sym.getAlignment();
497 uint64_t Size = Sym.getCommonSize();
499 CommonSize += Align + Size;
500 SymbolsToAllocate.push_back(Sym);
503 // Allocate memory for the section
504 unsigned SectionID = Sections.size();
505 uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, sizeof(void *),
506 SectionID, StringRef(), false);
508 report_fatal_error("Unable to allocate memory for common symbols!");
510 Sections.push_back(SectionEntry("<common symbols>", Addr, CommonSize, 0));
511 memset(Addr, 0, CommonSize);
513 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
514 << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
516 // Assign the address of each symbol
517 for (auto &Sym : SymbolsToAllocate) {
518 uint32_t Align = Sym.getAlignment();
520 uint64_t Size = Sym.getCommonSize();
521 Check(Sym.getName(Name));
523 // This symbol has an alignment requirement.
524 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
526 Offset += AlignOffset;
528 uint32_t Flags = Sym.getFlags();
529 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
530 if (Flags & SymbolRef::SF_Weak)
531 RTDyldSymFlags |= JITSymbolFlags::Weak;
532 if (Flags & SymbolRef::SF_Exported)
533 RTDyldSymFlags |= JITSymbolFlags::Exported;
534 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
535 << format("%p", Addr) << "\n");
536 GlobalSymbolTable[Name] =
537 SymbolTableEntry(SectionID, Offset, RTDyldSymFlags);
543 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
544 const SectionRef &Section, bool IsCode) {
547 uint64_t Alignment64 = Section.getAlignment();
549 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
550 unsigned PaddingSize = 0;
551 unsigned StubBufSize = 0;
553 bool IsRequired = isRequiredForExecution(Section);
554 bool IsVirtual = Section.isVirtual();
555 bool IsZeroInit = isZeroInit(Section);
556 bool IsReadOnly = isReadOnlyData(Section);
557 uint64_t DataSize = Section.getSize();
558 Check(Section.getName(Name));
560 StubBufSize = computeSectionStubBufSize(Obj, Section);
562 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
563 // with zeroes added at the end. For MachO objects, this section has a
564 // slightly different name, so this won't have any effect for MachO objects.
565 if (Name == ".eh_frame")
569 unsigned SectionID = Sections.size();
571 const char *pData = nullptr;
573 // In either case, set the location of the unrelocated section in memory,
574 // since we still process relocations for it even if we're not applying them.
575 Check(Section.getContents(data));
576 // Virtual sections have no data in the object image, so leave pData = 0
580 // Some sections, such as debug info, don't need to be loaded for execution.
581 // Leave those where they are.
583 Allocate = DataSize + PaddingSize + StubBufSize;
586 Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID,
588 : MemMgr.allocateDataSection(Allocate, Alignment, SectionID,
591 report_fatal_error("Unable to allocate section memory!");
593 // Zero-initialize or copy the data from the image
594 if (IsZeroInit || IsVirtual)
595 memset(Addr, 0, DataSize);
597 memcpy(Addr, pData, DataSize);
599 // Fill in any extra bytes we allocated for padding
600 if (PaddingSize != 0) {
601 memset(Addr + DataSize, 0, PaddingSize);
602 // Update the DataSize variable so that the stub offset is set correctly.
603 DataSize += PaddingSize;
606 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
607 << " obj addr: " << format("%p", pData)
608 << " new addr: " << format("%p", Addr)
609 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
610 << " Allocate: " << Allocate << "\n");
612 // Even if we didn't load the section, we need to record an entry for it
613 // to handle later processing (and by 'handle' I mean don't do anything
614 // with these sections).
617 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
618 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
619 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
620 << " Allocate: " << Allocate << "\n");
623 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
626 Checker->registerSection(Obj.getFileName(), SectionID);
631 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
632 const SectionRef &Section,
634 ObjSectionToIDMap &LocalSections) {
636 unsigned SectionID = 0;
637 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
638 if (i != LocalSections.end())
639 SectionID = i->second;
641 SectionID = emitSection(Obj, Section, IsCode);
642 LocalSections[Section] = SectionID;
647 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
648 unsigned SectionID) {
649 Relocations[SectionID].push_back(RE);
652 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
653 StringRef SymbolName) {
654 // Relocation by symbol. If the symbol is found in the global symbol table,
655 // create an appropriate section relocation. Otherwise, add it to
656 // ExternalSymbolRelocations.
657 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
658 if (Loc == GlobalSymbolTable.end()) {
659 ExternalSymbolRelocations[SymbolName].push_back(RE);
661 // Copy the RE since we want to modify its addend.
662 RelocationEntry RECopy = RE;
663 const auto &SymInfo = Loc->second;
664 RECopy.Addend += SymInfo.getOffset();
665 Relocations[SymInfo.getSectionID()].push_back(RECopy);
669 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
670 unsigned AbiVariant) {
671 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
672 // This stub has to be able to access the full address space,
673 // since symbol lookup won't necessarily find a handy, in-range,
674 // PLT stub for functions which could be anywhere.
675 // Stub can use ip0 (== x16) to calculate address
676 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
677 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
678 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
679 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
680 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
683 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
684 // TODO: There is only ARM far stub now. We should add the Thumb stub,
685 // and stubs for branches Thumb - ARM and ARM - Thumb.
686 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
688 } else if (IsMipsO32ABI) {
689 // 0: 3c190000 lui t9,%hi(addr).
690 // 4: 27390000 addiu t9,t9,%lo(addr).
691 // 8: 03200008 jr t9.
693 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
694 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
696 writeBytesUnaligned(LuiT9Instr, Addr, 4);
697 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
698 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
699 writeBytesUnaligned(NopInstr, Addr+12, 4);
701 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
702 // Depending on which version of the ELF ABI is in use, we need to
703 // generate one of two variants of the stub. They both start with
704 // the same sequence to load the target address into r12.
705 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
706 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
707 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
708 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
709 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
710 if (AbiVariant == 2) {
711 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
712 // The address is already in r12 as required by the ABI. Branch to it.
713 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
714 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
715 writeInt32BE(Addr+28, 0x4E800420); // bctr
717 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
718 // Load the function address on r11 and sets it to control register. Also
719 // loads the function TOC in r2 and environment pointer to r11.
720 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
721 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
722 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
723 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
724 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
725 writeInt32BE(Addr+40, 0x4E800420); // bctr
728 } else if (Arch == Triple::systemz) {
729 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
730 writeInt16BE(Addr+2, 0x0000);
731 writeInt16BE(Addr+4, 0x0004);
732 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
733 // 8-byte address stored at Addr + 8
735 } else if (Arch == Triple::x86_64) {
737 *(Addr+1) = 0x25; // rip
738 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
739 } else if (Arch == Triple::x86) {
740 *Addr = 0xE9; // 32-bit pc-relative jump.
745 // Assign an address to a symbol name and resolve all the relocations
746 // associated with it.
747 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
749 // The address to use for relocation resolution is not
750 // the address of the local section buffer. We must be doing
751 // a remote execution environment of some sort. Relocations can't
752 // be applied until all the sections have been moved. The client must
753 // trigger this with a call to MCJIT::finalize() or
754 // RuntimeDyld::resolveRelocations().
756 // Addr is a uint64_t because we can't assume the pointer width
757 // of the target is the same as that of the host. Just use a generic
758 // "big enough" type.
759 DEBUG(dbgs() << "Reassigning address for section "
760 << SectionID << " (" << Sections[SectionID].Name << "): "
761 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
762 << format("0x%016" PRIx64, Addr) << "\n");
763 Sections[SectionID].LoadAddress = Addr;
766 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
768 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
769 const RelocationEntry &RE = Relocs[i];
770 // Ignore relocations for sections that were not loaded
771 if (Sections[RE.SectionID].Address == nullptr)
773 resolveRelocation(RE, Value);
777 void RuntimeDyldImpl::resolveExternalSymbols() {
778 while (!ExternalSymbolRelocations.empty()) {
779 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
781 StringRef Name = i->first();
782 if (Name.size() == 0) {
783 // This is an absolute symbol, use an address of zero.
784 DEBUG(dbgs() << "Resolving absolute relocations."
786 RelocationList &Relocs = i->second;
787 resolveRelocationList(Relocs, 0);
790 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
791 if (Loc == GlobalSymbolTable.end()) {
792 // This is an external symbol, try to get its address from the symbol
794 Addr = Resolver.findSymbol(Name.data()).getAddress();
795 // The call to getSymbolAddress may have caused additional modules to
796 // be loaded, which may have added new entries to the
797 // ExternalSymbolRelocations map. Consquently, we need to update our
798 // iterator. This is also why retrieval of the relocation list
799 // associated with this symbol is deferred until below this point.
800 // New entries may have been added to the relocation list.
801 i = ExternalSymbolRelocations.find(Name);
803 // We found the symbol in our global table. It was probably in a
804 // Module that we loaded previously.
805 const auto &SymInfo = Loc->second;
806 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
810 // FIXME: Implement error handling that doesn't kill the host program!
812 report_fatal_error("Program used external function '" + Name +
813 "' which could not be resolved!");
815 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
816 << format("0x%lx", Addr) << "\n");
817 // This list may have been updated when we called getSymbolAddress, so
818 // don't change this code to get the list earlier.
819 RelocationList &Relocs = i->second;
820 resolveRelocationList(Relocs, Addr);
823 ExternalSymbolRelocations.erase(i);
827 //===----------------------------------------------------------------------===//
828 // RuntimeDyld class implementation
830 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
831 StringRef SectionName) const {
832 for (unsigned I = BeginIdx; I != EndIdx; ++I)
833 if (RTDyld.Sections[I].Name == SectionName)
834 return RTDyld.Sections[I].LoadAddress;
839 void RuntimeDyld::MemoryManager::anchor() {}
840 void RuntimeDyld::SymbolResolver::anchor() {}
842 RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
843 RuntimeDyld::SymbolResolver &Resolver)
844 : MemMgr(MemMgr), Resolver(Resolver) {
845 // FIXME: There's a potential issue lurking here if a single instance of
846 // RuntimeDyld is used to load multiple objects. The current implementation
847 // associates a single memory manager with a RuntimeDyld instance. Even
848 // though the public class spawns a new 'impl' instance for each load,
849 // they share a single memory manager. This can become a problem when page
850 // permissions are applied.
852 ProcessAllSections = false;
856 RuntimeDyld::~RuntimeDyld() {}
858 static std::unique_ptr<RuntimeDyldCOFF>
859 createRuntimeDyldCOFF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
860 RuntimeDyld::SymbolResolver &Resolver,
861 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
862 std::unique_ptr<RuntimeDyldCOFF> Dyld =
863 RuntimeDyldCOFF::create(Arch, MM, Resolver);
864 Dyld->setProcessAllSections(ProcessAllSections);
865 Dyld->setRuntimeDyldChecker(Checker);
869 static std::unique_ptr<RuntimeDyldELF>
870 createRuntimeDyldELF(RuntimeDyld::MemoryManager &MM,
871 RuntimeDyld::SymbolResolver &Resolver,
872 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
873 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM, Resolver));
874 Dyld->setProcessAllSections(ProcessAllSections);
875 Dyld->setRuntimeDyldChecker(Checker);
879 static std::unique_ptr<RuntimeDyldMachO>
880 createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
881 RuntimeDyld::SymbolResolver &Resolver,
882 bool ProcessAllSections,
883 RuntimeDyldCheckerImpl *Checker) {
884 std::unique_ptr<RuntimeDyldMachO> Dyld =
885 RuntimeDyldMachO::create(Arch, MM, Resolver);
886 Dyld->setProcessAllSections(ProcessAllSections);
887 Dyld->setRuntimeDyldChecker(Checker);
891 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
892 RuntimeDyld::loadObject(const ObjectFile &Obj) {
895 Dyld = createRuntimeDyldELF(MemMgr, Resolver, ProcessAllSections, Checker);
896 else if (Obj.isMachO())
897 Dyld = createRuntimeDyldMachO(
898 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
899 ProcessAllSections, Checker);
900 else if (Obj.isCOFF())
901 Dyld = createRuntimeDyldCOFF(
902 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
903 ProcessAllSections, Checker);
905 report_fatal_error("Incompatible object format!");
908 if (!Dyld->isCompatibleFile(Obj))
909 report_fatal_error("Incompatible object format!");
911 return Dyld->loadObject(Obj);
914 void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
917 return Dyld->getSymbolLocalAddress(Name);
920 RuntimeDyld::SymbolInfo RuntimeDyld::getSymbol(StringRef Name) const {
923 return Dyld->getSymbol(Name);
926 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
928 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
929 Dyld->reassignSectionAddress(SectionID, Addr);
932 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
933 uint64_t TargetAddress) {
934 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
937 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
939 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
941 void RuntimeDyld::registerEHFrames() {
943 Dyld->registerEHFrames();
946 void RuntimeDyld::deregisterEHFrames() {
948 Dyld->deregisterEHFrames();
951 } // end namespace llvm