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, SectionRef Sec,
118 ErrorOr<uint64_t> AddressOrErr = Sym.getAddress();
119 if (std::error_code EC = AddressOrErr.getError())
121 Result = *AddressOrErr - Sec.getAddress();
122 return std::error_code();
125 RuntimeDyldImpl::ObjSectionToIDMap
126 RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
127 MutexGuard locked(lock);
129 // Save information about our target
130 Arch = (Triple::ArchType)Obj.getArch();
131 IsTargetLittleEndian = Obj.isLittleEndian();
134 // Compute the memory size required to load all sections to be loaded
135 // and pass this information to the memory manager
136 if (MemMgr.needsToReserveAllocationSpace()) {
137 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
138 computeTotalAllocSize(Obj, CodeSize, DataSizeRO, DataSizeRW);
139 MemMgr.reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
142 // Used sections from the object file
143 ObjSectionToIDMap LocalSections;
145 // Common symbols requiring allocation, with their sizes and alignments
146 CommonSymbolList CommonSymbols;
149 DEBUG(dbgs() << "Parse symbols:\n");
150 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
152 uint32_t Flags = I->getFlags();
154 bool IsCommon = Flags & SymbolRef::SF_Common;
156 CommonSymbols.push_back(*I);
158 object::SymbolRef::Type SymType = I->getType();
160 if (SymType == object::SymbolRef::ST_Function ||
161 SymType == object::SymbolRef::ST_Data ||
162 SymType == object::SymbolRef::ST_Unknown) {
164 ErrorOr<StringRef> NameOrErr = I->getName();
165 Check(NameOrErr.getError());
166 StringRef Name = *NameOrErr;
167 section_iterator SI = Obj.section_end();
168 Check(I->getSection(SI));
169 if (SI == Obj.section_end())
172 Check(getOffset(*I, *SI, SectOffset));
173 StringRef SectionData;
174 Check(SI->getContents(SectionData));
175 bool IsCode = SI->isText();
177 findOrEmitSection(Obj, *SI, IsCode, LocalSections);
178 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
179 << " SID: " << SectionID << " Offset: "
180 << format("%p", (uintptr_t)SectOffset)
181 << " flags: " << Flags << "\n");
182 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
183 if (Flags & SymbolRef::SF_Weak)
184 RTDyldSymFlags |= JITSymbolFlags::Weak;
185 if (Flags & SymbolRef::SF_Exported)
186 RTDyldSymFlags |= JITSymbolFlags::Exported;
187 GlobalSymbolTable[Name] =
188 SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
193 // Allocate common symbols
194 emitCommonSymbols(Obj, CommonSymbols);
196 // Parse and process relocations
197 DEBUG(dbgs() << "Parse relocations:\n");
198 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
200 unsigned SectionID = 0;
202 section_iterator RelocatedSection = SI->getRelocatedSection();
204 if (RelocatedSection == SE)
207 relocation_iterator I = SI->relocation_begin();
208 relocation_iterator E = SI->relocation_end();
210 if (I == E && !ProcessAllSections)
213 bool IsCode = RelocatedSection->isText();
215 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
216 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
219 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
221 // If there is an attached checker, notify it about the stubs for this
222 // section so that they can be verified.
224 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
227 // Give the subclasses a chance to tie-up any loose ends.
228 finalizeLoad(Obj, LocalSections);
230 // for (auto E : LocalSections)
231 // llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
233 return LocalSections;
236 // A helper method for computeTotalAllocSize.
237 // Computes the memory size required to allocate sections with the given sizes,
238 // assuming that all sections are allocated with the given alignment
240 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
241 uint64_t Alignment) {
242 uint64_t TotalSize = 0;
243 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
244 uint64_t AlignedSize =
245 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
246 TotalSize += AlignedSize;
251 static bool isRequiredForExecution(const SectionRef Section) {
252 const ObjectFile *Obj = Section.getObject();
253 if (isa<object::ELFObjectFileBase>(Obj))
254 return ELFSectionRef(Section).getFlags() & ELF::SHF_ALLOC;
255 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) {
256 const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
257 // Avoid loading zero-sized COFF sections.
258 // In PE files, VirtualSize gives the section size, and SizeOfRawData
259 // may be zero for sections with content. In Obj files, SizeOfRawData
260 // gives the section size, and VirtualSize is always zero. Hence
261 // the need to check for both cases below.
262 bool HasContent = (CoffSection->VirtualSize > 0)
263 || (CoffSection->SizeOfRawData > 0);
264 bool IsDiscardable = CoffSection->Characteristics &
265 (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
266 return HasContent && !IsDiscardable;
269 assert(isa<MachOObjectFile>(Obj));
273 static bool isReadOnlyData(const SectionRef Section) {
274 const ObjectFile *Obj = Section.getObject();
275 if (isa<object::ELFObjectFileBase>(Obj))
276 return !(ELFSectionRef(Section).getFlags() &
277 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
278 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
279 return ((COFFObj->getCOFFSection(Section)->Characteristics &
280 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
281 | COFF::IMAGE_SCN_MEM_READ
282 | COFF::IMAGE_SCN_MEM_WRITE))
284 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
285 | COFF::IMAGE_SCN_MEM_READ));
287 assert(isa<MachOObjectFile>(Obj));
291 static bool isZeroInit(const SectionRef Section) {
292 const ObjectFile *Obj = Section.getObject();
293 if (isa<object::ELFObjectFileBase>(Obj))
294 return ELFSectionRef(Section).getType() == ELF::SHT_NOBITS;
295 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
296 return COFFObj->getCOFFSection(Section)->Characteristics &
297 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
299 auto *MachO = cast<MachOObjectFile>(Obj);
300 unsigned SectionType = MachO->getSectionType(Section);
301 return SectionType == MachO::S_ZEROFILL ||
302 SectionType == MachO::S_GB_ZEROFILL;
305 // Compute an upper bound of the memory size that is required to load all
307 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
309 uint64_t &DataSizeRO,
310 uint64_t &DataSizeRW) {
311 // Compute the size of all sections required for execution
312 std::vector<uint64_t> CodeSectionSizes;
313 std::vector<uint64_t> ROSectionSizes;
314 std::vector<uint64_t> RWSectionSizes;
315 uint64_t MaxAlignment = sizeof(void *);
317 // Collect sizes of all sections to be loaded;
318 // also determine the max alignment of all sections
319 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
321 const SectionRef &Section = *SI;
323 bool IsRequired = isRequiredForExecution(Section);
325 // Consider only the sections that are required to be loaded for execution
328 uint64_t DataSize = Section.getSize();
329 uint64_t Alignment64 = Section.getAlignment();
330 bool IsCode = Section.isText();
331 bool IsReadOnly = isReadOnlyData(Section);
332 Check(Section.getName(Name));
333 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
335 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
336 uint64_t SectionSize = DataSize + StubBufSize;
338 // The .eh_frame section (at least on Linux) needs an extra four bytes
340 // with zeroes added at the end. For MachO objects, this section has a
341 // slightly different name, so this won't have any effect for MachO
343 if (Name == ".eh_frame")
350 CodeSectionSizes.push_back(SectionSize);
351 } else if (IsReadOnly) {
352 ROSectionSizes.push_back(SectionSize);
354 RWSectionSizes.push_back(SectionSize);
357 // update the max alignment
358 if (Alignment > MaxAlignment) {
359 MaxAlignment = Alignment;
364 // Compute the size of all common symbols
365 uint64_t CommonSize = 0;
366 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
368 uint32_t Flags = I->getFlags();
369 if (Flags & SymbolRef::SF_Common) {
370 // Add the common symbols to a list. We'll allocate them all below.
371 uint64_t Size = I->getCommonSize();
375 if (CommonSize != 0) {
376 RWSectionSizes.push_back(CommonSize);
379 // Compute the required allocation space for each different type of sections
380 // (code, read-only data, read-write data) assuming that all sections are
381 // allocated with the max alignment. Note that we cannot compute with the
382 // individual alignments of the sections, because then the required size
383 // depends on the order, in which the sections are allocated.
384 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
385 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
386 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
389 // compute stub buffer size for the given section
390 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
391 const SectionRef &Section) {
392 unsigned StubSize = getMaxStubSize();
396 // FIXME: this is an inefficient way to handle this. We should computed the
397 // necessary section allocation size in loadObject by walking all the sections
399 unsigned StubBufSize = 0;
400 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
402 section_iterator RelSecI = SI->getRelocatedSection();
403 if (!(RelSecI == Section))
406 for (const RelocationRef &Reloc : SI->relocations()) {
408 StubBufSize += StubSize;
412 // Get section data size and alignment
413 uint64_t DataSize = Section.getSize();
414 uint64_t Alignment64 = Section.getAlignment();
416 // Add stubbuf size alignment
417 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
418 unsigned StubAlignment = getStubAlignment();
419 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
420 if (StubAlignment > EndAlignment)
421 StubBufSize += StubAlignment - EndAlignment;
425 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
426 unsigned Size) const {
428 if (IsTargetLittleEndian) {
431 Result = (Result << 8) | *Src--;
434 Result = (Result << 8) | *Src++;
439 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
440 unsigned Size) const {
441 if (IsTargetLittleEndian) {
443 *Dst++ = Value & 0xFF;
449 *Dst-- = Value & 0xFF;
455 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
456 CommonSymbolList &CommonSymbols) {
457 if (CommonSymbols.empty())
460 uint64_t CommonSize = 0;
461 CommonSymbolList SymbolsToAllocate;
463 DEBUG(dbgs() << "Processing common symbols...\n");
465 for (const auto &Sym : CommonSymbols) {
466 ErrorOr<StringRef> NameOrErr = Sym.getName();
467 Check(NameOrErr.getError());
468 StringRef Name = *NameOrErr;
470 // Skip common symbols already elsewhere.
471 if (GlobalSymbolTable.count(Name) ||
472 Resolver.findSymbolInLogicalDylib(Name)) {
473 DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name
478 uint32_t Align = Sym.getAlignment();
479 uint64_t Size = Sym.getCommonSize();
481 CommonSize += Align + Size;
482 SymbolsToAllocate.push_back(Sym);
485 // Allocate memory for the section
486 unsigned SectionID = Sections.size();
487 uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, sizeof(void *),
488 SectionID, StringRef(), false);
490 report_fatal_error("Unable to allocate memory for common symbols!");
492 Sections.push_back(SectionEntry("<common symbols>", Addr, CommonSize, 0));
493 memset(Addr, 0, CommonSize);
495 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
496 << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
498 // Assign the address of each symbol
499 for (auto &Sym : SymbolsToAllocate) {
500 uint32_t Align = Sym.getAlignment();
501 uint64_t Size = Sym.getCommonSize();
502 ErrorOr<StringRef> NameOrErr = Sym.getName();
503 Check(NameOrErr.getError());
504 StringRef Name = *NameOrErr;
506 // This symbol has an alignment requirement.
507 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
509 Offset += AlignOffset;
511 uint32_t Flags = Sym.getFlags();
512 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
513 if (Flags & SymbolRef::SF_Weak)
514 RTDyldSymFlags |= JITSymbolFlags::Weak;
515 if (Flags & SymbolRef::SF_Exported)
516 RTDyldSymFlags |= JITSymbolFlags::Exported;
517 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
518 << format("%p", Addr) << "\n");
519 GlobalSymbolTable[Name] =
520 SymbolTableEntry(SectionID, Offset, RTDyldSymFlags);
526 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
527 const SectionRef &Section, bool IsCode) {
530 uint64_t Alignment64 = Section.getAlignment();
532 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
533 unsigned PaddingSize = 0;
534 unsigned StubBufSize = 0;
536 bool IsRequired = isRequiredForExecution(Section);
537 bool IsVirtual = Section.isVirtual();
538 bool IsZeroInit = isZeroInit(Section);
539 bool IsReadOnly = isReadOnlyData(Section);
540 uint64_t DataSize = Section.getSize();
541 Check(Section.getName(Name));
543 StubBufSize = computeSectionStubBufSize(Obj, Section);
545 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
546 // with zeroes added at the end. For MachO objects, this section has a
547 // slightly different name, so this won't have any effect for MachO objects.
548 if (Name == ".eh_frame")
552 unsigned SectionID = Sections.size();
554 const char *pData = nullptr;
556 // In either case, set the location of the unrelocated section in memory,
557 // since we still process relocations for it even if we're not applying them.
558 Check(Section.getContents(data));
559 // Virtual sections have no data in the object image, so leave pData = 0
563 // Some sections, such as debug info, don't need to be loaded for execution.
564 // Leave those where they are.
566 Allocate = DataSize + PaddingSize + StubBufSize;
569 Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID,
571 : MemMgr.allocateDataSection(Allocate, Alignment, SectionID,
574 report_fatal_error("Unable to allocate section memory!");
576 // Zero-initialize or copy the data from the image
577 if (IsZeroInit || IsVirtual)
578 memset(Addr, 0, DataSize);
580 memcpy(Addr, pData, DataSize);
582 // Fill in any extra bytes we allocated for padding
583 if (PaddingSize != 0) {
584 memset(Addr + DataSize, 0, PaddingSize);
585 // Update the DataSize variable so that the stub offset is set correctly.
586 DataSize += PaddingSize;
589 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
590 << " obj addr: " << format("%p", pData)
591 << " new addr: " << format("%p", Addr)
592 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
593 << " Allocate: " << Allocate << "\n");
595 // Even if we didn't load the section, we need to record an entry for it
596 // to handle later processing (and by 'handle' I mean don't do anything
597 // with these sections).
600 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
601 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
602 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
603 << " Allocate: " << Allocate << "\n");
606 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
609 Checker->registerSection(Obj.getFileName(), SectionID);
614 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
615 const SectionRef &Section,
617 ObjSectionToIDMap &LocalSections) {
619 unsigned SectionID = 0;
620 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
621 if (i != LocalSections.end())
622 SectionID = i->second;
624 SectionID = emitSection(Obj, Section, IsCode);
625 LocalSections[Section] = SectionID;
630 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
631 unsigned SectionID) {
632 Relocations[SectionID].push_back(RE);
635 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
636 StringRef SymbolName) {
637 // Relocation by symbol. If the symbol is found in the global symbol table,
638 // create an appropriate section relocation. Otherwise, add it to
639 // ExternalSymbolRelocations.
640 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
641 if (Loc == GlobalSymbolTable.end()) {
642 ExternalSymbolRelocations[SymbolName].push_back(RE);
644 // Copy the RE since we want to modify its addend.
645 RelocationEntry RECopy = RE;
646 const auto &SymInfo = Loc->second;
647 RECopy.Addend += SymInfo.getOffset();
648 Relocations[SymInfo.getSectionID()].push_back(RECopy);
652 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
653 unsigned AbiVariant) {
654 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
655 // This stub has to be able to access the full address space,
656 // since symbol lookup won't necessarily find a handy, in-range,
657 // PLT stub for functions which could be anywhere.
658 // Stub can use ip0 (== x16) to calculate address
659 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
660 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
661 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
662 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
663 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
666 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
667 // TODO: There is only ARM far stub now. We should add the Thumb stub,
668 // and stubs for branches Thumb - ARM and ARM - Thumb.
669 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
671 } else if (IsMipsO32ABI) {
672 // 0: 3c190000 lui t9,%hi(addr).
673 // 4: 27390000 addiu t9,t9,%lo(addr).
674 // 8: 03200008 jr t9.
676 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
677 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
679 writeBytesUnaligned(LuiT9Instr, Addr, 4);
680 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
681 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
682 writeBytesUnaligned(NopInstr, Addr+12, 4);
684 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
685 // Depending on which version of the ELF ABI is in use, we need to
686 // generate one of two variants of the stub. They both start with
687 // the same sequence to load the target address into r12.
688 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
689 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
690 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
691 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
692 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
693 if (AbiVariant == 2) {
694 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
695 // The address is already in r12 as required by the ABI. Branch to it.
696 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
697 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
698 writeInt32BE(Addr+28, 0x4E800420); // bctr
700 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
701 // Load the function address on r11 and sets it to control register. Also
702 // loads the function TOC in r2 and environment pointer to r11.
703 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
704 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
705 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
706 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
707 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
708 writeInt32BE(Addr+40, 0x4E800420); // bctr
711 } else if (Arch == Triple::systemz) {
712 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
713 writeInt16BE(Addr+2, 0x0000);
714 writeInt16BE(Addr+4, 0x0004);
715 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
716 // 8-byte address stored at Addr + 8
718 } else if (Arch == Triple::x86_64) {
720 *(Addr+1) = 0x25; // rip
721 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
722 } else if (Arch == Triple::x86) {
723 *Addr = 0xE9; // 32-bit pc-relative jump.
728 // Assign an address to a symbol name and resolve all the relocations
729 // associated with it.
730 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
732 // The address to use for relocation resolution is not
733 // the address of the local section buffer. We must be doing
734 // a remote execution environment of some sort. Relocations can't
735 // be applied until all the sections have been moved. The client must
736 // trigger this with a call to MCJIT::finalize() or
737 // RuntimeDyld::resolveRelocations().
739 // Addr is a uint64_t because we can't assume the pointer width
740 // of the target is the same as that of the host. Just use a generic
741 // "big enough" type.
742 DEBUG(dbgs() << "Reassigning address for section "
743 << SectionID << " (" << Sections[SectionID].Name << "): "
744 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
745 << format("0x%016" PRIx64, Addr) << "\n");
746 Sections[SectionID].LoadAddress = Addr;
749 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
751 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
752 const RelocationEntry &RE = Relocs[i];
753 // Ignore relocations for sections that were not loaded
754 if (Sections[RE.SectionID].Address == nullptr)
756 resolveRelocation(RE, Value);
760 void RuntimeDyldImpl::resolveExternalSymbols() {
761 while (!ExternalSymbolRelocations.empty()) {
762 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
764 StringRef Name = i->first();
765 if (Name.size() == 0) {
766 // This is an absolute symbol, use an address of zero.
767 DEBUG(dbgs() << "Resolving absolute relocations."
769 RelocationList &Relocs = i->second;
770 resolveRelocationList(Relocs, 0);
773 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
774 if (Loc == GlobalSymbolTable.end()) {
775 // This is an external symbol, try to get its address from the symbol
777 Addr = Resolver.findSymbol(Name.data()).getAddress();
778 // The call to getSymbolAddress may have caused additional modules to
779 // be loaded, which may have added new entries to the
780 // ExternalSymbolRelocations map. Consquently, we need to update our
781 // iterator. This is also why retrieval of the relocation list
782 // associated with this symbol is deferred until below this point.
783 // New entries may have been added to the relocation list.
784 i = ExternalSymbolRelocations.find(Name);
786 // We found the symbol in our global table. It was probably in a
787 // Module that we loaded previously.
788 const auto &SymInfo = Loc->second;
789 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
793 // FIXME: Implement error handling that doesn't kill the host program!
795 report_fatal_error("Program used external function '" + Name +
796 "' which could not be resolved!");
798 // If Resolver returned UINT64_MAX, the client wants to handle this symbol
799 // manually and we shouldn't resolve its relocations.
800 if (Addr != UINT64_MAX) {
801 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
802 << format("0x%lx", Addr) << "\n");
803 // This list may have been updated when we called getSymbolAddress, so
804 // don't change this code to get the list earlier.
805 RelocationList &Relocs = i->second;
806 resolveRelocationList(Relocs, Addr);
810 ExternalSymbolRelocations.erase(i);
814 //===----------------------------------------------------------------------===//
815 // RuntimeDyld class implementation
817 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
818 const object::SectionRef &Sec) const {
820 // llvm::dbgs() << "Searching for " << Sec.getRawDataRefImpl() << " in:\n";
821 // for (auto E : ObjSecToIDMap)
822 // llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
824 auto I = ObjSecToIDMap.find(Sec);
825 if (I != ObjSecToIDMap.end()) {
826 // llvm::dbgs() << "Found ID " << I->second << " for Sec: " << Sec.getRawDataRefImpl() << ", LoadAddress = " << RTDyld.Sections[I->second].LoadAddress << "\n";
827 return RTDyld.Sections[I->second].LoadAddress;
829 // llvm::dbgs() << "Not found.\n";
835 void RuntimeDyld::MemoryManager::anchor() {}
836 void RuntimeDyld::SymbolResolver::anchor() {}
838 RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
839 RuntimeDyld::SymbolResolver &Resolver)
840 : MemMgr(MemMgr), Resolver(Resolver) {
841 // FIXME: There's a potential issue lurking here if a single instance of
842 // RuntimeDyld is used to load multiple objects. The current implementation
843 // associates a single memory manager with a RuntimeDyld instance. Even
844 // though the public class spawns a new 'impl' instance for each load,
845 // they share a single memory manager. This can become a problem when page
846 // permissions are applied.
848 ProcessAllSections = false;
852 RuntimeDyld::~RuntimeDyld() {}
854 static std::unique_ptr<RuntimeDyldCOFF>
855 createRuntimeDyldCOFF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
856 RuntimeDyld::SymbolResolver &Resolver,
857 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
858 std::unique_ptr<RuntimeDyldCOFF> Dyld =
859 RuntimeDyldCOFF::create(Arch, MM, Resolver);
860 Dyld->setProcessAllSections(ProcessAllSections);
861 Dyld->setRuntimeDyldChecker(Checker);
865 static std::unique_ptr<RuntimeDyldELF>
866 createRuntimeDyldELF(RuntimeDyld::MemoryManager &MM,
867 RuntimeDyld::SymbolResolver &Resolver,
868 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
869 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM, Resolver));
870 Dyld->setProcessAllSections(ProcessAllSections);
871 Dyld->setRuntimeDyldChecker(Checker);
875 static std::unique_ptr<RuntimeDyldMachO>
876 createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
877 RuntimeDyld::SymbolResolver &Resolver,
878 bool ProcessAllSections,
879 RuntimeDyldCheckerImpl *Checker) {
880 std::unique_ptr<RuntimeDyldMachO> Dyld =
881 RuntimeDyldMachO::create(Arch, MM, Resolver);
882 Dyld->setProcessAllSections(ProcessAllSections);
883 Dyld->setRuntimeDyldChecker(Checker);
887 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
888 RuntimeDyld::loadObject(const ObjectFile &Obj) {
891 Dyld = createRuntimeDyldELF(MemMgr, Resolver, ProcessAllSections, Checker);
892 else if (Obj.isMachO())
893 Dyld = createRuntimeDyldMachO(
894 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
895 ProcessAllSections, Checker);
896 else if (Obj.isCOFF())
897 Dyld = createRuntimeDyldCOFF(
898 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
899 ProcessAllSections, Checker);
901 report_fatal_error("Incompatible object format!");
904 if (!Dyld->isCompatibleFile(Obj))
905 report_fatal_error("Incompatible object format!");
907 return Dyld->loadObject(Obj);
910 void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
913 return Dyld->getSymbolLocalAddress(Name);
916 RuntimeDyld::SymbolInfo RuntimeDyld::getSymbol(StringRef Name) const {
919 return Dyld->getSymbol(Name);
922 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
924 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
925 Dyld->reassignSectionAddress(SectionID, Addr);
928 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
929 uint64_t TargetAddress) {
930 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
933 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
935 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
937 void RuntimeDyld::registerEHFrames() {
939 Dyld->registerEHFrames();
942 void RuntimeDyld::deregisterEHFrames() {
944 Dyld->deregisterEHFrames();
947 } // end namespace llvm