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 "ObjectImageCommon.h"
17 #include "RuntimeDyldELF.h"
18 #include "RuntimeDyldImpl.h"
19 #include "RuntimeDyldMachO.h"
20 #include "llvm/Support/FileSystem.h"
21 #include "llvm/Support/MathExtras.h"
22 #include "llvm/Object/ELF.h"
25 using namespace llvm::object;
27 // Empty out-of-line virtual destructor as the key function.
28 RuntimeDyldImpl::~RuntimeDyldImpl() {}
32 StringRef RuntimeDyldImpl::getEHFrameSection() {
36 // Resolve the relocations for all symbols we currently know about.
37 void RuntimeDyldImpl::resolveRelocations() {
38 // First, resolve relocations associated with external symbols.
39 resolveExternalSymbols();
41 // Just iterate over the sections we have and resolve all the relocations
42 // in them. Gross overkill, but it gets the job done.
43 for (int i = 0, e = Sections.size(); i != e; ++i) {
44 uint64_t Addr = Sections[i].LoadAddress;
45 DEBUG(dbgs() << "Resolving relocations Section #" << i
46 << "\t" << format("%p", (uint8_t *)Addr)
48 resolveRelocationList(Relocations[i], Addr);
52 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
53 uint64_t TargetAddress) {
54 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
55 if (Sections[i].Address == LocalAddress) {
56 reassignSectionAddress(i, TargetAddress);
60 llvm_unreachable("Attempting to remap address of unknown section!");
63 // Subclasses can implement this method to create specialized image instances.
64 // The caller owns the pointer that is returned.
65 ObjectImage *RuntimeDyldImpl::createObjectImage(ObjectBuffer *InputBuffer) {
66 return new ObjectImageCommon(InputBuffer);
69 ObjectImage *RuntimeDyldImpl::loadObject(ObjectBuffer *InputBuffer) {
70 OwningPtr<ObjectImage> obj(createObjectImage(InputBuffer));
72 report_fatal_error("Unable to create object image from memory buffer!");
74 Arch = (Triple::ArchType)obj->getArch();
76 // Symbols found in this object
77 StringMap<SymbolLoc> LocalSymbols;
78 // Used sections from the object file
79 ObjSectionToIDMap LocalSections;
81 // Common symbols requiring allocation, with their sizes and alignments
82 CommonSymbolMap CommonSymbols;
83 // Maximum required total memory to allocate all common symbols
84 uint64_t CommonSize = 0;
88 DEBUG(dbgs() << "Parse symbols:\n");
89 for (symbol_iterator i = obj->begin_symbols(), e = obj->end_symbols();
90 i != e; i.increment(err)) {
92 object::SymbolRef::Type SymType;
94 Check(i->getType(SymType));
95 Check(i->getName(Name));
98 Check(i->getFlags(flags));
100 bool isCommon = flags & SymbolRef::SF_Common;
102 // Add the common symbols to a list. We'll allocate them all below.
104 Check(i->getAlignment(Align));
106 Check(i->getSize(Size));
107 CommonSize += Size + Align;
108 CommonSymbols[*i] = CommonSymbolInfo(Size, Align);
110 if (SymType == object::SymbolRef::ST_Function ||
111 SymType == object::SymbolRef::ST_Data ||
112 SymType == object::SymbolRef::ST_Unknown) {
114 StringRef SectionData;
116 section_iterator si = obj->end_sections();
117 Check(i->getFileOffset(FileOffset));
118 Check(i->getSection(si));
119 if (si == obj->end_sections()) continue;
120 Check(si->getContents(SectionData));
121 Check(si->isText(IsCode));
122 const uint8_t* SymPtr = (const uint8_t*)InputBuffer->getBufferStart() +
123 (uintptr_t)FileOffset;
124 uintptr_t SectOffset = (uintptr_t)(SymPtr -
125 (const uint8_t*)SectionData.begin());
126 unsigned SectionID = findOrEmitSection(*obj, *si, IsCode, LocalSections);
127 LocalSymbols[Name.data()] = SymbolLoc(SectionID, SectOffset);
128 DEBUG(dbgs() << "\tFileOffset: " << format("%p", (uintptr_t)FileOffset)
129 << " flags: " << flags
130 << " SID: " << SectionID
131 << " Offset: " << format("%p", SectOffset));
132 GlobalSymbolTable[Name] = SymbolLoc(SectionID, SectOffset);
135 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name << "\n");
138 // Allocate common symbols
140 emitCommonSymbols(*obj, CommonSymbols, CommonSize, LocalSymbols);
142 // Parse and process relocations
143 DEBUG(dbgs() << "Parse relocations:\n");
144 for (section_iterator si = obj->begin_sections(),
145 se = obj->end_sections(); si != se; si.increment(err)) {
147 bool isFirstRelocation = true;
148 unsigned SectionID = 0;
150 section_iterator RelocatedSection = si->getRelocatedSection();
152 for (relocation_iterator i = si->begin_relocations(),
153 e = si->end_relocations(); i != e; i.increment(err)) {
156 // If it's the first relocation in this section, find its SectionID
157 if (isFirstRelocation) {
159 findOrEmitSection(*obj, *RelocatedSection, true, LocalSections);
160 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
161 isFirstRelocation = false;
164 processRelocationRef(SectionID, *i, *obj, LocalSections, LocalSymbols,
172 void RuntimeDyldImpl::emitCommonSymbols(ObjectImage &Obj,
173 const CommonSymbolMap &CommonSymbols,
175 SymbolTableMap &SymbolTable) {
176 // Allocate memory for the section
177 unsigned SectionID = Sections.size();
178 uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, sizeof(void*),
181 report_fatal_error("Unable to allocate memory for common symbols!");
183 Sections.push_back(SectionEntry(StringRef(), Addr, TotalSize, 0));
184 memset(Addr, 0, TotalSize);
186 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID
187 << " new addr: " << format("%p", Addr)
188 << " DataSize: " << TotalSize
191 // Assign the address of each symbol
192 for (CommonSymbolMap::const_iterator it = CommonSymbols.begin(),
193 itEnd = CommonSymbols.end(); it != itEnd; it++) {
194 uint64_t Size = it->second.first;
195 uint64_t Align = it->second.second;
197 it->first.getName(Name);
199 // This symbol has an alignment requirement.
200 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
202 Offset += AlignOffset;
203 DEBUG(dbgs() << "Allocating common symbol " << Name << " address " <<
204 format("%p\n", Addr));
206 Obj.updateSymbolAddress(it->first, (uint64_t)Addr);
207 SymbolTable[Name.data()] = SymbolLoc(SectionID, Offset);
213 unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
214 const SectionRef &Section,
217 unsigned StubBufSize = 0,
218 StubSize = getMaxStubSize();
220 const ObjectFile *ObjFile = Obj.getObjectFile();
221 // FIXME: this is an inefficient way to handle this. We should computed the
222 // necessary section allocation size in loadObject by walking all the sections
225 for (section_iterator SI = ObjFile->begin_sections(),
226 SE = ObjFile->end_sections();
227 SI != SE; SI.increment(err), Check(err)) {
228 section_iterator RelSecI = SI->getRelocatedSection();
229 if (!(RelSecI == Section))
232 for (relocation_iterator I = SI->begin_relocations(),
233 E = SI->end_relocations(); I != E; I.increment(err), Check(err)) {
234 StubBufSize += StubSize;
240 uint64_t Alignment64;
241 Check(Section.getContents(data));
242 Check(Section.getAlignment(Alignment64));
244 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
251 Check(Section.isRequiredForExecution(IsRequired));
252 Check(Section.isVirtual(IsVirtual));
253 Check(Section.isZeroInit(IsZeroInit));
254 Check(Section.isReadOnlyData(IsReadOnly));
255 Check(Section.getSize(DataSize));
256 Check(Section.getName(Name));
258 unsigned StubAlignment = getStubAlignment();
259 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
260 if (StubAlignment > EndAlignment)
261 StubBufSize += StubAlignment - EndAlignment;
265 unsigned SectionID = Sections.size();
267 const char *pData = 0;
269 // Some sections, such as debug info, don't need to be loaded for execution.
270 // Leave those where they are.
272 Allocate = DataSize + StubBufSize;
274 ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID)
275 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID, IsReadOnly);
277 report_fatal_error("Unable to allocate section memory!");
279 // Virtual sections have no data in the object image, so leave pData = 0
283 // Zero-initialize or copy the data from the image
284 if (IsZeroInit || IsVirtual)
285 memset(Addr, 0, DataSize);
287 memcpy(Addr, pData, DataSize);
289 DEBUG(dbgs() << "emitSection SectionID: " << SectionID
291 << " obj addr: " << format("%p", pData)
292 << " new addr: " << format("%p", Addr)
293 << " DataSize: " << DataSize
294 << " StubBufSize: " << StubBufSize
295 << " Allocate: " << Allocate
297 Obj.updateSectionAddress(Section, (uint64_t)Addr);
300 // Even if we didn't load the section, we need to record an entry for it
301 // to handle later processing (and by 'handle' I mean don't do anything
302 // with these sections).
305 DEBUG(dbgs() << "emitSection SectionID: " << SectionID
307 << " obj addr: " << format("%p", data.data())
309 << " DataSize: " << DataSize
310 << " StubBufSize: " << StubBufSize
311 << " Allocate: " << Allocate
315 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
319 unsigned RuntimeDyldImpl::findOrEmitSection(ObjectImage &Obj,
320 const SectionRef &Section,
322 ObjSectionToIDMap &LocalSections) {
324 unsigned SectionID = 0;
325 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
326 if (i != LocalSections.end())
327 SectionID = i->second;
329 SectionID = emitSection(Obj, Section, IsCode);
330 LocalSections[Section] = SectionID;
335 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
336 unsigned SectionID) {
337 Relocations[SectionID].push_back(RE);
340 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
341 StringRef SymbolName) {
342 // Relocation by symbol. If the symbol is found in the global symbol table,
343 // create an appropriate section relocation. Otherwise, add it to
344 // ExternalSymbolRelocations.
345 SymbolTableMap::const_iterator Loc =
346 GlobalSymbolTable.find(SymbolName);
347 if (Loc == GlobalSymbolTable.end()) {
348 ExternalSymbolRelocations[SymbolName].push_back(RE);
350 // Copy the RE since we want to modify its addend.
351 RelocationEntry RECopy = RE;
352 RECopy.Addend += Loc->second.second;
353 Relocations[Loc->second.first].push_back(RECopy);
357 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr) {
358 if (Arch == Triple::aarch64) {
359 // This stub has to be able to access the full address space,
360 // since symbol lookup won't necessarily find a handy, in-range,
361 // PLT stub for functions which could be anywhere.
362 uint32_t *StubAddr = (uint32_t*)Addr;
364 // Stub can use ip0 (== x16) to calculate address
365 *StubAddr = 0xd2e00010; // movz ip0, #:abs_g3:<addr>
367 *StubAddr = 0xf2c00010; // movk ip0, #:abs_g2_nc:<addr>
369 *StubAddr = 0xf2a00010; // movk ip0, #:abs_g1_nc:<addr>
371 *StubAddr = 0xf2800010; // movk ip0, #:abs_g0_nc:<addr>
373 *StubAddr = 0xd61f0200; // br ip0
376 } else if (Arch == Triple::arm) {
377 // TODO: There is only ARM far stub now. We should add the Thumb stub,
378 // and stubs for branches Thumb - ARM and ARM - Thumb.
379 uint32_t *StubAddr = (uint32_t*)Addr;
380 *StubAddr = 0xe51ff004; // ldr pc,<label>
381 return (uint8_t*)++StubAddr;
382 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
383 uint32_t *StubAddr = (uint32_t*)Addr;
384 // 0: 3c190000 lui t9,%hi(addr).
385 // 4: 27390000 addiu t9,t9,%lo(addr).
386 // 8: 03200008 jr t9.
388 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
389 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
391 *StubAddr = LuiT9Instr;
393 *StubAddr = AdduiT9Instr;
395 *StubAddr = JrT9Instr;
397 *StubAddr = NopInstr;
399 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
400 // PowerPC64 stub: the address points to a function descriptor
401 // instead of the function itself. Load the function address
402 // on r11 and sets it to control register. Also loads the function
403 // TOC in r2 and environment pointer to r11.
404 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
405 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
406 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
407 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
408 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
409 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
410 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
411 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
412 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
413 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
414 writeInt32BE(Addr+40, 0x4E800420); // bctr
417 } else if (Arch == Triple::systemz) {
418 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
419 writeInt16BE(Addr+2, 0x0000);
420 writeInt16BE(Addr+4, 0x0004);
421 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
422 // 8-byte address stored at Addr + 8
428 // Assign an address to a symbol name and resolve all the relocations
429 // associated with it.
430 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
432 // The address to use for relocation resolution is not
433 // the address of the local section buffer. We must be doing
434 // a remote execution environment of some sort. Relocations can't
435 // be applied until all the sections have been moved. The client must
436 // trigger this with a call to MCJIT::finalize() or
437 // RuntimeDyld::resolveRelocations().
439 // Addr is a uint64_t because we can't assume the pointer width
440 // of the target is the same as that of the host. Just use a generic
441 // "big enough" type.
442 Sections[SectionID].LoadAddress = Addr;
445 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
447 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
448 const RelocationEntry &RE = Relocs[i];
449 // Ignore relocations for sections that were not loaded
450 if (Sections[RE.SectionID].Address == 0)
452 resolveRelocation(RE, Value);
456 void RuntimeDyldImpl::resolveExternalSymbols() {
457 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin(),
458 e = ExternalSymbolRelocations.end();
459 for (; i != e; i++) {
460 StringRef Name = i->first();
461 RelocationList &Relocs = i->second;
462 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(Name);
463 if (Loc == GlobalSymbolTable.end()) {
464 if (Name.size() == 0) {
465 // This is an absolute symbol, use an address of zero.
466 DEBUG(dbgs() << "Resolving absolute relocations." << "\n");
467 resolveRelocationList(Relocs, 0);
469 // This is an external symbol, try to get its address from
471 uint8_t *Addr = (uint8_t*) MemMgr->getPointerToNamedFunction(Name.data(),
473 DEBUG(dbgs() << "Resolving relocations Name: " << Name
474 << "\t" << format("%p", Addr)
476 resolveRelocationList(Relocs, (uintptr_t)Addr);
479 report_fatal_error("Expected external symbol");
485 //===----------------------------------------------------------------------===//
486 // RuntimeDyld class implementation
487 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
488 // FIXME: There's a potential issue lurking here if a single instance of
489 // RuntimeDyld is used to load multiple objects. The current implementation
490 // associates a single memory manager with a RuntimeDyld instance. Even
491 // though the public class spawns a new 'impl' instance for each load,
492 // they share a single memory manager. This can become a problem when page
493 // permissions are applied.
498 RuntimeDyld::~RuntimeDyld() {
502 ObjectImage *RuntimeDyld::loadObject(ObjectBuffer *InputBuffer) {
504 sys::fs::file_magic Type =
505 sys::fs::identify_magic(InputBuffer->getBuffer());
507 case sys::fs::file_magic::elf_relocatable:
508 case sys::fs::file_magic::elf_executable:
509 case sys::fs::file_magic::elf_shared_object:
510 case sys::fs::file_magic::elf_core:
511 Dyld = new RuntimeDyldELF(MM);
513 case sys::fs::file_magic::macho_object:
514 case sys::fs::file_magic::macho_executable:
515 case sys::fs::file_magic::macho_fixed_virtual_memory_shared_lib:
516 case sys::fs::file_magic::macho_core:
517 case sys::fs::file_magic::macho_preload_executable:
518 case sys::fs::file_magic::macho_dynamically_linked_shared_lib:
519 case sys::fs::file_magic::macho_dynamic_linker:
520 case sys::fs::file_magic::macho_bundle:
521 case sys::fs::file_magic::macho_dynamically_linked_shared_lib_stub:
522 case sys::fs::file_magic::macho_dsym_companion:
523 Dyld = new RuntimeDyldMachO(MM);
525 case sys::fs::file_magic::unknown:
526 case sys::fs::file_magic::bitcode:
527 case sys::fs::file_magic::archive:
528 case sys::fs::file_magic::coff_object:
529 case sys::fs::file_magic::pecoff_executable:
530 case sys::fs::file_magic::macho_universal_binary:
531 report_fatal_error("Incompatible object format!");
534 if (!Dyld->isCompatibleFormat(InputBuffer))
535 report_fatal_error("Incompatible object format!");
538 return Dyld->loadObject(InputBuffer);
541 void *RuntimeDyld::getSymbolAddress(StringRef Name) {
542 return Dyld->getSymbolAddress(Name);
545 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) {
546 return Dyld->getSymbolLoadAddress(Name);
549 void RuntimeDyld::resolveRelocations() {
550 Dyld->resolveRelocations();
553 void RuntimeDyld::reassignSectionAddress(unsigned SectionID,
555 Dyld->reassignSectionAddress(SectionID, Addr);
558 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
559 uint64_t TargetAddress) {
560 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
563 StringRef RuntimeDyld::getErrorString() {
564 return Dyld->getErrorString();
567 StringRef RuntimeDyld::getEHFrameSection() {
568 return Dyld->getEHFrameSection();
571 } // end namespace llvm