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 #define DEBUG_TYPE "dyld"
15 #include "llvm/ExecutionEngine/RuntimeDyld.h"
16 #include "JITRegistrar.h"
17 #include "ObjectImageCommon.h"
18 #include "RuntimeDyldELF.h"
19 #include "RuntimeDyldImpl.h"
20 #include "RuntimeDyldMachO.h"
21 #include "llvm/Object/ELF.h"
22 #include "llvm/Support/FileSystem.h"
23 #include "llvm/Support/MathExtras.h"
24 #include "llvm/Support/MutexGuard.h"
27 using namespace llvm::object;
29 // Empty out-of-line virtual destructor as the key function.
30 RuntimeDyldImpl::~RuntimeDyldImpl() {}
32 // Pin the JITRegistrar's and ObjectImage*'s vtables to this file.
33 void JITRegistrar::anchor() {}
34 void ObjectImage::anchor() {}
35 void ObjectImageCommon::anchor() {}
39 void RuntimeDyldImpl::registerEHFrames() {
42 void RuntimeDyldImpl::deregisterEHFrames() {
45 // Resolve the relocations for all symbols we currently know about.
46 void RuntimeDyldImpl::resolveRelocations() {
47 MutexGuard locked(lock);
49 // First, resolve relocations associated with external symbols.
50 resolveExternalSymbols();
52 // Just iterate over the sections we have and resolve all the relocations
53 // in them. Gross overkill, but it gets the job done.
54 for (int i = 0, e = Sections.size(); i != e; ++i) {
55 // The Section here (Sections[i]) refers to the section in which the
56 // symbol for the relocation is located. The SectionID in the relocation
57 // entry provides the section to which the relocation will be applied.
58 uint64_t Addr = Sections[i].LoadAddress;
59 DEBUG(dbgs() << "Resolving relocations Section #" << i
60 << "\t" << format("%p", (uint8_t *)Addr)
62 resolveRelocationList(Relocations[i], Addr);
67 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
68 uint64_t TargetAddress) {
69 MutexGuard locked(lock);
70 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
71 if (Sections[i].Address == LocalAddress) {
72 reassignSectionAddress(i, TargetAddress);
76 llvm_unreachable("Attempting to remap address of unknown section!");
79 // Subclasses can implement this method to create specialized image instances.
80 // The caller owns the pointer that is returned.
81 ObjectImage *RuntimeDyldImpl::createObjectImage(ObjectBuffer *InputBuffer) {
82 return new ObjectImageCommon(InputBuffer);
85 ObjectImage *RuntimeDyldImpl::createObjectImageFromFile(ObjectFile *InputObject) {
86 return new ObjectImageCommon(InputObject);
89 ObjectImage *RuntimeDyldImpl::loadObject(ObjectFile *InputObject) {
90 return loadObject(createObjectImageFromFile(InputObject));
93 ObjectImage *RuntimeDyldImpl::loadObject(ObjectBuffer *InputBuffer) {
94 return loadObject(createObjectImage(InputBuffer));
97 ObjectImage *RuntimeDyldImpl::loadObject(ObjectImage *InputObject) {
98 MutexGuard locked(lock);
100 OwningPtr<ObjectImage> obj(InputObject);
104 // Save information about our target
105 Arch = (Triple::ArchType)obj->getArch();
106 IsTargetLittleEndian = obj->getObjectFile()->isLittleEndian();
108 // Symbols found in this object
109 StringMap<SymbolLoc> LocalSymbols;
110 // Used sections from the object file
111 ObjSectionToIDMap LocalSections;
113 // Common symbols requiring allocation, with their sizes and alignments
114 CommonSymbolMap CommonSymbols;
115 // Maximum required total memory to allocate all common symbols
116 uint64_t CommonSize = 0;
119 DEBUG(dbgs() << "Parse symbols:\n");
120 for (symbol_iterator i = obj->begin_symbols(), e = obj->end_symbols(); i != e;
122 object::SymbolRef::Type SymType;
124 Check(i->getType(SymType));
125 Check(i->getName(Name));
128 Check(i->getFlags(flags));
130 bool isCommon = flags & SymbolRef::SF_Common;
132 // Add the common symbols to a list. We'll allocate them all below.
134 Check(i->getAlignment(Align));
136 Check(i->getSize(Size));
137 CommonSize += Size + Align;
138 CommonSymbols[*i] = CommonSymbolInfo(Size, Align);
140 if (SymType == object::SymbolRef::ST_Function ||
141 SymType == object::SymbolRef::ST_Data ||
142 SymType == object::SymbolRef::ST_Unknown) {
144 StringRef SectionData;
146 section_iterator si = obj->end_sections();
147 Check(i->getFileOffset(FileOffset));
148 Check(i->getSection(si));
149 if (si == obj->end_sections()) continue;
150 Check(si->getContents(SectionData));
151 Check(si->isText(IsCode));
152 const uint8_t* SymPtr = (const uint8_t*)InputObject->getData().data() +
153 (uintptr_t)FileOffset;
154 uintptr_t SectOffset = (uintptr_t)(SymPtr -
155 (const uint8_t*)SectionData.begin());
156 unsigned SectionID = findOrEmitSection(*obj, *si, IsCode, LocalSections);
157 LocalSymbols[Name.data()] = SymbolLoc(SectionID, SectOffset);
158 DEBUG(dbgs() << "\tFileOffset: " << format("%p", (uintptr_t)FileOffset)
159 << " flags: " << flags
160 << " SID: " << SectionID
161 << " Offset: " << format("%p", SectOffset));
162 GlobalSymbolTable[Name] = SymbolLoc(SectionID, SectOffset);
165 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name << "\n");
168 // Allocate common symbols
170 emitCommonSymbols(*obj, CommonSymbols, CommonSize, LocalSymbols);
172 // Parse and process relocations
173 DEBUG(dbgs() << "Parse relocations:\n");
174 for (section_iterator si = obj->begin_sections(), se = obj->end_sections();
176 bool isFirstRelocation = true;
177 unsigned SectionID = 0;
179 section_iterator RelocatedSection = si->getRelocatedSection();
181 for (relocation_iterator i = si->begin_relocations(),
182 e = si->end_relocations();
184 // If it's the first relocation in this section, find its SectionID
185 if (isFirstRelocation) {
187 findOrEmitSection(*obj, *RelocatedSection, true, LocalSections);
188 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
189 isFirstRelocation = false;
192 processRelocationRef(SectionID, *i, *obj, LocalSections, LocalSymbols,
197 // Give the subclasses a chance to tie-up any loose ends.
198 finalizeLoad(LocalSections);
203 void RuntimeDyldImpl::emitCommonSymbols(ObjectImage &Obj,
204 const CommonSymbolMap &CommonSymbols,
206 SymbolTableMap &SymbolTable) {
207 // Allocate memory for the section
208 unsigned SectionID = Sections.size();
209 uint8_t *Addr = MemMgr->allocateDataSection(
210 TotalSize, sizeof(void*), SectionID, StringRef(), false);
212 report_fatal_error("Unable to allocate memory for common symbols!");
214 Sections.push_back(SectionEntry(StringRef(), Addr, TotalSize, 0));
215 memset(Addr, 0, TotalSize);
217 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID
218 << " new addr: " << format("%p", Addr)
219 << " DataSize: " << TotalSize
222 // Assign the address of each symbol
223 for (CommonSymbolMap::const_iterator it = CommonSymbols.begin(),
224 itEnd = CommonSymbols.end(); it != itEnd; it++) {
225 uint64_t Size = it->second.first;
226 uint64_t Align = it->second.second;
228 it->first.getName(Name);
230 // This symbol has an alignment requirement.
231 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
233 Offset += AlignOffset;
234 DEBUG(dbgs() << "Allocating common symbol " << Name << " address " <<
235 format("%p\n", Addr));
237 Obj.updateSymbolAddress(it->first, (uint64_t)Addr);
238 SymbolTable[Name.data()] = SymbolLoc(SectionID, Offset);
244 unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
245 const SectionRef &Section,
248 unsigned StubBufSize = 0,
249 StubSize = getMaxStubSize();
250 const ObjectFile *ObjFile = Obj.getObjectFile();
251 // FIXME: this is an inefficient way to handle this. We should computed the
252 // necessary section allocation size in loadObject by walking all the sections
255 for (section_iterator SI = ObjFile->begin_sections(),
256 SE = ObjFile->end_sections();
258 section_iterator RelSecI = SI->getRelocatedSection();
259 if (!(RelSecI == Section))
262 for (relocation_iterator I = SI->begin_relocations(),
263 E = SI->end_relocations();
265 StubBufSize += StubSize;
271 uint64_t Alignment64;
272 Check(Section.getContents(data));
273 Check(Section.getAlignment(Alignment64));
275 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
281 unsigned PaddingSize = 0;
283 Check(Section.isRequiredForExecution(IsRequired));
284 Check(Section.isVirtual(IsVirtual));
285 Check(Section.isZeroInit(IsZeroInit));
286 Check(Section.isReadOnlyData(IsReadOnly));
287 Check(Section.getSize(DataSize));
288 Check(Section.getName(Name));
290 unsigned StubAlignment = getStubAlignment();
291 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
292 if (StubAlignment > EndAlignment)
293 StubBufSize += StubAlignment - EndAlignment;
296 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
297 // with zeroes added at the end. For MachO objects, this section has a
298 // slightly different name, so this won't have any effect for MachO objects.
299 if (Name == ".eh_frame")
303 unsigned SectionID = Sections.size();
305 const char *pData = 0;
307 // Some sections, such as debug info, don't need to be loaded for execution.
308 // Leave those where they are.
310 Allocate = DataSize + PaddingSize + StubBufSize;
312 ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID, Name)
313 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID, Name,
316 report_fatal_error("Unable to allocate section memory!");
318 // Virtual sections have no data in the object image, so leave pData = 0
322 // Zero-initialize or copy the data from the image
323 if (IsZeroInit || IsVirtual)
324 memset(Addr, 0, DataSize);
326 memcpy(Addr, pData, DataSize);
328 // Fill in any extra bytes we allocated for padding
329 if (PaddingSize != 0) {
330 memset(Addr + DataSize, 0, PaddingSize);
331 // Update the DataSize variable so that the stub offset is set correctly.
332 DataSize += PaddingSize;
335 DEBUG(dbgs() << "emitSection SectionID: " << SectionID
337 << " obj addr: " << format("%p", pData)
338 << " new addr: " << format("%p", Addr)
339 << " DataSize: " << DataSize
340 << " StubBufSize: " << StubBufSize
341 << " Allocate: " << Allocate
343 Obj.updateSectionAddress(Section, (uint64_t)Addr);
346 // Even if we didn't load the section, we need to record an entry for it
347 // to handle later processing (and by 'handle' I mean don't do anything
348 // with these sections).
351 DEBUG(dbgs() << "emitSection SectionID: " << SectionID
353 << " obj addr: " << format("%p", data.data())
355 << " DataSize: " << DataSize
356 << " StubBufSize: " << StubBufSize
357 << " Allocate: " << Allocate
361 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
365 unsigned RuntimeDyldImpl::findOrEmitSection(ObjectImage &Obj,
366 const SectionRef &Section,
368 ObjSectionToIDMap &LocalSections) {
370 unsigned SectionID = 0;
371 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
372 if (i != LocalSections.end())
373 SectionID = i->second;
375 SectionID = emitSection(Obj, Section, IsCode);
376 LocalSections[Section] = SectionID;
381 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
382 unsigned SectionID) {
383 Relocations[SectionID].push_back(RE);
386 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
387 StringRef SymbolName) {
388 // Relocation by symbol. If the symbol is found in the global symbol table,
389 // create an appropriate section relocation. Otherwise, add it to
390 // ExternalSymbolRelocations.
391 SymbolTableMap::const_iterator Loc =
392 GlobalSymbolTable.find(SymbolName);
393 if (Loc == GlobalSymbolTable.end()) {
394 ExternalSymbolRelocations[SymbolName].push_back(RE);
396 // Copy the RE since we want to modify its addend.
397 RelocationEntry RECopy = RE;
398 RECopy.Addend += Loc->second.second;
399 Relocations[Loc->second.first].push_back(RECopy);
403 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr) {
404 if (Arch == Triple::aarch64) {
405 // This stub has to be able to access the full address space,
406 // since symbol lookup won't necessarily find a handy, in-range,
407 // PLT stub for functions which could be anywhere.
408 uint32_t *StubAddr = (uint32_t*)Addr;
410 // Stub can use ip0 (== x16) to calculate address
411 *StubAddr = 0xd2e00010; // movz ip0, #:abs_g3:<addr>
413 *StubAddr = 0xf2c00010; // movk ip0, #:abs_g2_nc:<addr>
415 *StubAddr = 0xf2a00010; // movk ip0, #:abs_g1_nc:<addr>
417 *StubAddr = 0xf2800010; // movk ip0, #:abs_g0_nc:<addr>
419 *StubAddr = 0xd61f0200; // br ip0
422 } else if (Arch == Triple::arm) {
423 // TODO: There is only ARM far stub now. We should add the Thumb stub,
424 // and stubs for branches Thumb - ARM and ARM - Thumb.
425 uint32_t *StubAddr = (uint32_t*)Addr;
426 *StubAddr = 0xe51ff004; // ldr pc,<label>
427 return (uint8_t*)++StubAddr;
428 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
429 uint32_t *StubAddr = (uint32_t*)Addr;
430 // 0: 3c190000 lui t9,%hi(addr).
431 // 4: 27390000 addiu t9,t9,%lo(addr).
432 // 8: 03200008 jr t9.
434 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
435 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
437 *StubAddr = LuiT9Instr;
439 *StubAddr = AdduiT9Instr;
441 *StubAddr = JrT9Instr;
443 *StubAddr = NopInstr;
445 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
446 // PowerPC64 stub: the address points to a function descriptor
447 // instead of the function itself. Load the function address
448 // on r11 and sets it to control register. Also loads the function
449 // TOC in r2 and environment pointer to r11.
450 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
451 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
452 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
453 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
454 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
455 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
456 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
457 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
458 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
459 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
460 writeInt32BE(Addr+40, 0x4E800420); // bctr
463 } else if (Arch == Triple::systemz) {
464 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
465 writeInt16BE(Addr+2, 0x0000);
466 writeInt16BE(Addr+4, 0x0004);
467 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
468 // 8-byte address stored at Addr + 8
470 } else if (Arch == Triple::x86_64) {
472 *(Addr+1) = 0x25; // rip
473 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
478 // Assign an address to a symbol name and resolve all the relocations
479 // associated with it.
480 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
482 // The address to use for relocation resolution is not
483 // the address of the local section buffer. We must be doing
484 // a remote execution environment of some sort. Relocations can't
485 // be applied until all the sections have been moved. The client must
486 // trigger this with a call to MCJIT::finalize() or
487 // RuntimeDyld::resolveRelocations().
489 // Addr is a uint64_t because we can't assume the pointer width
490 // of the target is the same as that of the host. Just use a generic
491 // "big enough" type.
492 Sections[SectionID].LoadAddress = Addr;
495 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
497 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
498 const RelocationEntry &RE = Relocs[i];
499 // Ignore relocations for sections that were not loaded
500 if (Sections[RE.SectionID].Address == 0)
502 resolveRelocation(RE, Value);
506 void RuntimeDyldImpl::resolveExternalSymbols() {
507 while(!ExternalSymbolRelocations.empty()) {
508 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
510 StringRef Name = i->first();
511 if (Name.size() == 0) {
512 // This is an absolute symbol, use an address of zero.
513 DEBUG(dbgs() << "Resolving absolute relocations." << "\n");
514 RelocationList &Relocs = i->second;
515 resolveRelocationList(Relocs, 0);
518 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(Name);
519 if (Loc == GlobalSymbolTable.end()) {
520 // This is an external symbol, try to get its address from
522 Addr = MemMgr->getSymbolAddress(Name.data());
523 // The call to getSymbolAddress may have caused additional modules to
524 // be loaded, which may have added new entries to the
525 // ExternalSymbolRelocations map. Consquently, we need to update our
526 // iterator. This is also why retrieval of the relocation list
527 // associated with this symbol is deferred until below this point.
528 // New entries may have been added to the relocation list.
529 i = ExternalSymbolRelocations.find(Name);
531 // We found the symbol in our global table. It was probably in a
532 // Module that we loaded previously.
533 SymbolLoc SymLoc = Loc->second;
534 Addr = getSectionLoadAddress(SymLoc.first) + SymLoc.second;
537 // FIXME: Implement error handling that doesn't kill the host program!
539 report_fatal_error("Program used external function '" + Name +
540 "' which could not be resolved!");
542 updateGOTEntries(Name, Addr);
543 DEBUG(dbgs() << "Resolving relocations Name: " << Name
544 << "\t" << format("0x%lx", Addr)
546 // This list may have been updated when we called getSymbolAddress, so
547 // don't change this code to get the list earlier.
548 RelocationList &Relocs = i->second;
549 resolveRelocationList(Relocs, Addr);
552 ExternalSymbolRelocations.erase(i);
557 //===----------------------------------------------------------------------===//
558 // RuntimeDyld class implementation
559 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
560 // FIXME: There's a potential issue lurking here if a single instance of
561 // RuntimeDyld is used to load multiple objects. The current implementation
562 // associates a single memory manager with a RuntimeDyld instance. Even
563 // though the public class spawns a new 'impl' instance for each load,
564 // they share a single memory manager. This can become a problem when page
565 // permissions are applied.
570 RuntimeDyld::~RuntimeDyld() {
574 ObjectImage *RuntimeDyld::loadObject(ObjectFile *InputObject) {
576 if (InputObject->isELF())
577 Dyld = new RuntimeDyldELF(MM);
578 else if (InputObject->isMachO())
579 Dyld = new RuntimeDyldMachO(MM);
581 report_fatal_error("Incompatible object format!");
583 if (!Dyld->isCompatibleFile(InputObject))
584 report_fatal_error("Incompatible object format!");
587 return Dyld->loadObject(InputObject);
590 ObjectImage *RuntimeDyld::loadObject(ObjectBuffer *InputBuffer) {
592 sys::fs::file_magic Type =
593 sys::fs::identify_magic(InputBuffer->getBuffer());
595 case sys::fs::file_magic::elf_relocatable:
596 case sys::fs::file_magic::elf_executable:
597 case sys::fs::file_magic::elf_shared_object:
598 case sys::fs::file_magic::elf_core:
599 Dyld = new RuntimeDyldELF(MM);
601 case sys::fs::file_magic::macho_object:
602 case sys::fs::file_magic::macho_executable:
603 case sys::fs::file_magic::macho_fixed_virtual_memory_shared_lib:
604 case sys::fs::file_magic::macho_core:
605 case sys::fs::file_magic::macho_preload_executable:
606 case sys::fs::file_magic::macho_dynamically_linked_shared_lib:
607 case sys::fs::file_magic::macho_dynamic_linker:
608 case sys::fs::file_magic::macho_bundle:
609 case sys::fs::file_magic::macho_dynamically_linked_shared_lib_stub:
610 case sys::fs::file_magic::macho_dsym_companion:
611 Dyld = new RuntimeDyldMachO(MM);
613 case sys::fs::file_magic::unknown:
614 case sys::fs::file_magic::bitcode:
615 case sys::fs::file_magic::archive:
616 case sys::fs::file_magic::coff_object:
617 case sys::fs::file_magic::coff_import_library:
618 case sys::fs::file_magic::pecoff_executable:
619 case sys::fs::file_magic::macho_universal_binary:
620 case sys::fs::file_magic::windows_resource:
621 report_fatal_error("Incompatible object format!");
624 if (!Dyld->isCompatibleFormat(InputBuffer))
625 report_fatal_error("Incompatible object format!");
628 return Dyld->loadObject(InputBuffer);
631 void *RuntimeDyld::getSymbolAddress(StringRef Name) {
634 return Dyld->getSymbolAddress(Name);
637 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) {
640 return Dyld->getSymbolLoadAddress(Name);
643 void RuntimeDyld::resolveRelocations() {
644 Dyld->resolveRelocations();
647 void RuntimeDyld::reassignSectionAddress(unsigned SectionID,
649 Dyld->reassignSectionAddress(SectionID, Addr);
652 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
653 uint64_t TargetAddress) {
654 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
657 StringRef RuntimeDyld::getErrorString() {
658 return Dyld->getErrorString();
661 void RuntimeDyld::registerEHFrames() {
663 Dyld->registerEHFrames();
666 void RuntimeDyld::deregisterEHFrames() {
668 Dyld->deregisterEHFrames();
671 } // end namespace llvm