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/ELF.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 // Symbols found in this object
159 StringMap<SymbolLoc> LocalSymbols;
160 // Used sections from the object file
161 ObjSectionToIDMap LocalSections;
163 // Common symbols requiring allocation, with their sizes and alignments
164 CommonSymbolMap CommonSymbols;
165 // Maximum required total memory to allocate all common symbols
166 uint64_t CommonSize = 0;
169 DEBUG(dbgs() << "Parse symbols:\n");
170 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
172 object::SymbolRef::Type SymType;
174 Check(I->getType(SymType));
175 Check(I->getName(Name));
177 uint32_t Flags = I->getFlags();
179 bool IsCommon = Flags & SymbolRef::SF_Common;
181 // Add the common symbols to a list. We'll allocate them all below.
182 if (!GlobalSymbolTable.count(Name)) {
184 Check(I->getAlignment(Align));
186 Check(I->getSize(Size));
187 CommonSize += Size + Align;
188 CommonSymbols[*I] = CommonSymbolInfo(Size, Align);
191 if (SymType == object::SymbolRef::ST_Function ||
192 SymType == object::SymbolRef::ST_Data ||
193 SymType == object::SymbolRef::ST_Unknown) {
195 StringRef SectionData;
196 section_iterator SI = Obj.section_end();
197 Check(getOffset(*I, SectOffset));
198 Check(I->getSection(SI));
199 if (SI == Obj.section_end())
201 Check(SI->getContents(SectionData));
202 bool IsCode = SI->isText();
204 findOrEmitSection(Obj, *SI, IsCode, LocalSections);
205 LocalSymbols[Name.data()] = SymbolLoc(SectionID, SectOffset);
206 DEBUG(dbgs() << "\tOffset: " << format("%p", (uintptr_t)SectOffset)
207 << " flags: " << Flags << " SID: " << SectionID);
208 GlobalSymbolTable[Name] = SymbolLoc(SectionID, SectOffset);
211 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name << "\n");
214 // Allocate common symbols
216 emitCommonSymbols(Obj, CommonSymbols, CommonSize, GlobalSymbolTable);
218 // Parse and process relocations
219 DEBUG(dbgs() << "Parse relocations:\n");
220 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
222 unsigned SectionID = 0;
224 section_iterator RelocatedSection = SI->getRelocatedSection();
226 relocation_iterator I = SI->relocation_begin();
227 relocation_iterator E = SI->relocation_end();
229 if (I == E && !ProcessAllSections)
232 bool IsCode = RelocatedSection->isText();
234 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
235 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
238 I = processRelocationRef(SectionID, I, Obj, LocalSections, LocalSymbols,
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 // Compute an upper bound of the memory size that is required to load all
272 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
274 uint64_t &DataSizeRO,
275 uint64_t &DataSizeRW) {
276 // Compute the size of all sections required for execution
277 std::vector<uint64_t> CodeSectionSizes;
278 std::vector<uint64_t> ROSectionSizes;
279 std::vector<uint64_t> RWSectionSizes;
280 uint64_t MaxAlignment = sizeof(void *);
282 // Collect sizes of all sections to be loaded;
283 // also determine the max alignment of all sections
284 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
286 const SectionRef &Section = *SI;
288 bool IsRequired = Section.isRequiredForExecution();
290 // Consider only the sections that are required to be loaded for execution
293 uint64_t DataSize = Section.getSize();
294 uint64_t Alignment64 = Section.getAlignment();
295 bool IsCode = Section.isText();
296 bool IsReadOnly = Section.isReadOnlyData();
297 Check(Section.getName(Name));
298 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
300 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
301 uint64_t SectionSize = DataSize + StubBufSize;
303 // The .eh_frame section (at least on Linux) needs an extra four bytes
305 // with zeroes added at the end. For MachO objects, this section has a
306 // slightly different name, so this won't have any effect for MachO
308 if (Name == ".eh_frame")
311 if (SectionSize > 0) {
312 // save the total size of the section
314 CodeSectionSizes.push_back(SectionSize);
315 } else if (IsReadOnly) {
316 ROSectionSizes.push_back(SectionSize);
318 RWSectionSizes.push_back(SectionSize);
320 // update the max alignment
321 if (Alignment > MaxAlignment) {
322 MaxAlignment = Alignment;
328 // Compute the size of all common symbols
329 uint64_t CommonSize = 0;
330 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
332 uint32_t Flags = I->getFlags();
333 if (Flags & SymbolRef::SF_Common) {
334 // Add the common symbols to a list. We'll allocate them all below.
336 Check(I->getSize(Size));
340 if (CommonSize != 0) {
341 RWSectionSizes.push_back(CommonSize);
344 // Compute the required allocation space for each different type of sections
345 // (code, read-only data, read-write data) assuming that all sections are
346 // allocated with the max alignment. Note that we cannot compute with the
347 // individual alignments of the sections, because then the required size
348 // depends on the order, in which the sections are allocated.
349 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
350 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
351 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
354 // compute stub buffer size for the given section
355 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
356 const SectionRef &Section) {
357 unsigned StubSize = getMaxStubSize();
361 // FIXME: this is an inefficient way to handle this. We should computed the
362 // necessary section allocation size in loadObject by walking all the sections
364 unsigned StubBufSize = 0;
365 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
367 section_iterator RelSecI = SI->getRelocatedSection();
368 if (!(RelSecI == Section))
371 for (const RelocationRef &Reloc : SI->relocations()) {
373 StubBufSize += StubSize;
377 // Get section data size and alignment
378 uint64_t DataSize = Section.getSize();
379 uint64_t Alignment64 = Section.getAlignment();
381 // Add stubbuf size alignment
382 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
383 unsigned StubAlignment = getStubAlignment();
384 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
385 if (StubAlignment > EndAlignment)
386 StubBufSize += StubAlignment - EndAlignment;
390 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
391 unsigned Size) const {
393 if (IsTargetLittleEndian) {
396 Result = (Result << 8) | *Src--;
399 Result = (Result << 8) | *Src++;
404 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
405 unsigned Size) const {
406 if (IsTargetLittleEndian) {
408 *Dst++ = Value & 0xFF;
414 *Dst-- = Value & 0xFF;
420 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
421 const CommonSymbolMap &CommonSymbols,
423 SymbolTableMap &SymbolTable) {
424 // Allocate memory for the section
425 unsigned SectionID = Sections.size();
426 uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, sizeof(void *),
427 SectionID, StringRef(), false);
429 report_fatal_error("Unable to allocate memory for common symbols!");
431 Sections.push_back(SectionEntry("<common symbols>", Addr, TotalSize, 0));
432 memset(Addr, 0, TotalSize);
434 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
435 << format("%p", Addr) << " DataSize: " << TotalSize << "\n");
437 // Assign the address of each symbol
438 for (CommonSymbolMap::const_iterator it = CommonSymbols.begin(),
439 itEnd = CommonSymbols.end(); it != itEnd; ++it) {
440 uint64_t Size = it->second.first;
441 uint64_t Align = it->second.second;
443 it->first.getName(Name);
445 // This symbol has an alignment requirement.
446 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
448 Offset += AlignOffset;
449 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
450 << format("%p\n", Addr));
452 SymbolTable[Name.data()] = SymbolLoc(SectionID, Offset);
458 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
459 const SectionRef &Section, bool IsCode) {
462 Check(Section.getContents(data));
463 uint64_t Alignment64 = Section.getAlignment();
465 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
466 unsigned PaddingSize = 0;
467 unsigned StubBufSize = 0;
469 bool IsRequired = Section.isRequiredForExecution();
470 bool IsVirtual = Section.isVirtual();
471 bool IsZeroInit = Section.isZeroInit();
472 bool IsReadOnly = Section.isReadOnlyData();
473 uint64_t DataSize = Section.getSize();
474 Check(Section.getName(Name));
476 StubBufSize = computeSectionStubBufSize(Obj, Section);
478 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
479 // with zeroes added at the end. For MachO objects, this section has a
480 // slightly different name, so this won't have any effect for MachO objects.
481 if (Name == ".eh_frame")
485 unsigned SectionID = Sections.size();
487 const char *pData = nullptr;
489 // Some sections, such as debug info, don't need to be loaded for execution.
490 // Leave those where they are.
492 Allocate = DataSize + PaddingSize + StubBufSize;
493 Addr = IsCode ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID,
495 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID,
498 report_fatal_error("Unable to allocate section memory!");
500 // Virtual sections have no data in the object image, so leave pData = 0
504 // Zero-initialize or copy the data from the image
505 if (IsZeroInit || IsVirtual)
506 memset(Addr, 0, DataSize);
508 memcpy(Addr, pData, DataSize);
510 // Fill in any extra bytes we allocated for padding
511 if (PaddingSize != 0) {
512 memset(Addr + DataSize, 0, PaddingSize);
513 // Update the DataSize variable so that the stub offset is set correctly.
514 DataSize += PaddingSize;
517 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
518 << " obj addr: " << format("%p", pData)
519 << " new addr: " << format("%p", Addr)
520 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
521 << " Allocate: " << Allocate << "\n");
523 // Even if we didn't load the section, we need to record an entry for it
524 // to handle later processing (and by 'handle' I mean don't do anything
525 // with these sections).
528 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
529 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
530 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
531 << " Allocate: " << Allocate << "\n");
534 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
537 Checker->registerSection(Obj.getFileName(), SectionID);
542 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
543 const SectionRef &Section,
545 ObjSectionToIDMap &LocalSections) {
547 unsigned SectionID = 0;
548 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
549 if (i != LocalSections.end())
550 SectionID = i->second;
552 SectionID = emitSection(Obj, Section, IsCode);
553 LocalSections[Section] = SectionID;
558 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
559 unsigned SectionID) {
560 Relocations[SectionID].push_back(RE);
563 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
564 StringRef SymbolName) {
565 // Relocation by symbol. If the symbol is found in the global symbol table,
566 // create an appropriate section relocation. Otherwise, add it to
567 // ExternalSymbolRelocations.
568 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
569 if (Loc == GlobalSymbolTable.end()) {
570 ExternalSymbolRelocations[SymbolName].push_back(RE);
572 // Copy the RE since we want to modify its addend.
573 RelocationEntry RECopy = RE;
574 RECopy.Addend += Loc->second.second;
575 Relocations[Loc->second.first].push_back(RECopy);
579 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
580 unsigned AbiVariant) {
581 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
582 // This stub has to be able to access the full address space,
583 // since symbol lookup won't necessarily find a handy, in-range,
584 // PLT stub for functions which could be anywhere.
585 // Stub can use ip0 (== x16) to calculate address
586 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
587 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
588 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
589 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
590 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
593 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
594 // TODO: There is only ARM far stub now. We should add the Thumb stub,
595 // and stubs for branches Thumb - ARM and ARM - Thumb.
596 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
598 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
599 // 0: 3c190000 lui t9,%hi(addr).
600 // 4: 27390000 addiu t9,t9,%lo(addr).
601 // 8: 03200008 jr t9.
603 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
604 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
606 writeBytesUnaligned(LuiT9Instr, Addr, 4);
607 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
608 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
609 writeBytesUnaligned(NopInstr, Addr+12, 4);
611 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
612 // Depending on which version of the ELF ABI is in use, we need to
613 // generate one of two variants of the stub. They both start with
614 // the same sequence to load the target address into r12.
615 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
616 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
617 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
618 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
619 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
620 if (AbiVariant == 2) {
621 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
622 // The address is already in r12 as required by the ABI. Branch to it.
623 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
624 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
625 writeInt32BE(Addr+28, 0x4E800420); // bctr
627 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
628 // Load the function address on r11 and sets it to control register. Also
629 // loads the function TOC in r2 and environment pointer to r11.
630 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
631 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
632 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
633 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
634 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
635 writeInt32BE(Addr+40, 0x4E800420); // bctr
638 } else if (Arch == Triple::systemz) {
639 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
640 writeInt16BE(Addr+2, 0x0000);
641 writeInt16BE(Addr+4, 0x0004);
642 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
643 // 8-byte address stored at Addr + 8
645 } else if (Arch == Triple::x86_64) {
647 *(Addr+1) = 0x25; // rip
648 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
649 } else if (Arch == Triple::x86) {
650 *Addr = 0xE9; // 32-bit pc-relative jump.
655 // Assign an address to a symbol name and resolve all the relocations
656 // associated with it.
657 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
659 // The address to use for relocation resolution is not
660 // the address of the local section buffer. We must be doing
661 // a remote execution environment of some sort. Relocations can't
662 // be applied until all the sections have been moved. The client must
663 // trigger this with a call to MCJIT::finalize() or
664 // RuntimeDyld::resolveRelocations().
666 // Addr is a uint64_t because we can't assume the pointer width
667 // of the target is the same as that of the host. Just use a generic
668 // "big enough" type.
669 DEBUG(dbgs() << "Reassigning address for section "
670 << SectionID << " (" << Sections[SectionID].Name << "): "
671 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
672 << format("0x%016" PRIx64, Addr) << "\n");
673 Sections[SectionID].LoadAddress = Addr;
676 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
678 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
679 const RelocationEntry &RE = Relocs[i];
680 // Ignore relocations for sections that were not loaded
681 if (Sections[RE.SectionID].Address == nullptr)
683 resolveRelocation(RE, Value);
687 void RuntimeDyldImpl::resolveExternalSymbols() {
688 while (!ExternalSymbolRelocations.empty()) {
689 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
691 StringRef Name = i->first();
692 if (Name.size() == 0) {
693 // This is an absolute symbol, use an address of zero.
694 DEBUG(dbgs() << "Resolving absolute relocations."
696 RelocationList &Relocs = i->second;
697 resolveRelocationList(Relocs, 0);
700 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(Name);
701 if (Loc == GlobalSymbolTable.end()) {
702 // This is an external symbol, try to get its address from
704 Addr = MemMgr->getSymbolAddress(Name.data());
705 // The call to getSymbolAddress may have caused additional modules to
706 // be loaded, which may have added new entries to the
707 // ExternalSymbolRelocations map. Consquently, we need to update our
708 // iterator. This is also why retrieval of the relocation list
709 // associated with this symbol is deferred until below this point.
710 // New entries may have been added to the relocation list.
711 i = ExternalSymbolRelocations.find(Name);
713 // We found the symbol in our global table. It was probably in a
714 // Module that we loaded previously.
715 SymbolLoc SymLoc = Loc->second;
716 Addr = getSectionLoadAddress(SymLoc.first) + SymLoc.second;
719 // FIXME: Implement error handling that doesn't kill the host program!
721 report_fatal_error("Program used external function '" + Name +
722 "' which could not be resolved!");
724 updateGOTEntries(Name, Addr);
725 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
726 << format("0x%lx", Addr) << "\n");
727 // This list may have been updated when we called getSymbolAddress, so
728 // don't change this code to get the list earlier.
729 RelocationList &Relocs = i->second;
730 resolveRelocationList(Relocs, Addr);
733 ExternalSymbolRelocations.erase(i);
737 //===----------------------------------------------------------------------===//
738 // RuntimeDyld class implementation
740 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
741 StringRef SectionName) const {
742 for (unsigned I = BeginIdx; I != EndIdx; ++I)
743 if (RTDyld.Sections[I].Name == SectionName)
744 return RTDyld.Sections[I].LoadAddress;
749 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
750 // FIXME: There's a potential issue lurking here if a single instance of
751 // RuntimeDyld is used to load multiple objects. The current implementation
752 // associates a single memory manager with a RuntimeDyld instance. Even
753 // though the public class spawns a new 'impl' instance for each load,
754 // they share a single memory manager. This can become a problem when page
755 // permissions are applied.
758 ProcessAllSections = false;
762 RuntimeDyld::~RuntimeDyld() {}
764 static std::unique_ptr<RuntimeDyldELF>
765 createRuntimeDyldELF(RTDyldMemoryManager *MM, bool ProcessAllSections,
766 RuntimeDyldCheckerImpl *Checker) {
767 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM));
768 Dyld->setProcessAllSections(ProcessAllSections);
769 Dyld->setRuntimeDyldChecker(Checker);
773 static std::unique_ptr<RuntimeDyldMachO>
774 createRuntimeDyldMachO(Triple::ArchType Arch, RTDyldMemoryManager *MM,
775 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
776 std::unique_ptr<RuntimeDyldMachO> Dyld(RuntimeDyldMachO::create(Arch, MM));
777 Dyld->setProcessAllSections(ProcessAllSections);
778 Dyld->setRuntimeDyldChecker(Checker);
782 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
783 RuntimeDyld::loadObject(const ObjectFile &Obj) {
786 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
787 else if (Obj.isMachO())
788 Dyld = createRuntimeDyldMachO(
789 static_cast<Triple::ArchType>(Obj.getArch()), MM,
790 ProcessAllSections, Checker);
792 report_fatal_error("Incompatible object format!");
795 if (!Dyld->isCompatibleFile(Obj))
796 report_fatal_error("Incompatible object format!");
798 return Dyld->loadObject(Obj);
801 void *RuntimeDyld::getSymbolAddress(StringRef Name) const {
804 return Dyld->getSymbolAddress(Name);
807 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) const {
810 return Dyld->getSymbolLoadAddress(Name);
813 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
815 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
816 Dyld->reassignSectionAddress(SectionID, Addr);
819 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
820 uint64_t TargetAddress) {
821 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
824 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
826 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
828 void RuntimeDyld::registerEHFrames() {
830 Dyld->registerEHFrames();
833 void RuntimeDyld::deregisterEHFrames() {
835 Dyld->deregisterEHFrames();
838 } // end namespace llvm