1//===-- RuntimeDyld.cpp - Run-time dynamic linker for MC-JIT ----*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Implementation of the MC-JIT runtime dynamic linker.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/ExecutionEngine/RuntimeDyld.h"
14#include "RuntimeDyldCOFF.h"
15#include "RuntimeDyldELF.h"
16#include "RuntimeDyldImpl.h"
17#include "RuntimeDyldMachO.h"
18#include "llvm/Object/COFF.h"
19#include "llvm/Object/ELFObjectFile.h"
20#include "llvm/Support/Alignment.h"
21#include "llvm/Support/MSVCErrorWorkarounds.h"
22#include "llvm/Support/MathExtras.h"
23#include <mutex>
24
25#include <future>
26
27using namespace llvm;
28using namespace llvm::object;
29
30#define DEBUG_TYPE "dyld"
31
32namespace {
33
34enum RuntimeDyldErrorCode {
35 GenericRTDyldError = 1
36};
37
38// FIXME: This class is only here to support the transition to llvm::Error. It
39// will be removed once this transition is complete. Clients should prefer to
40// deal with the Error value directly, rather than converting to error_code.
41class RuntimeDyldErrorCategory : public std::error_category {
42public:
43 const char *name() const noexcept override { return "runtimedyld"; }
44
45 std::string message(int Condition) const override {
46 switch (static_cast<RuntimeDyldErrorCode>(Condition)) {
47 case GenericRTDyldError: return "Generic RuntimeDyld error";
48 }
49 llvm_unreachable("Unrecognized RuntimeDyldErrorCode");
50 }
51};
52
53}
54
55char RuntimeDyldError::ID = 0;
56
57void RuntimeDyldError::log(raw_ostream &OS) const {
58 OS << ErrMsg << "\n";
59}
60
61std::error_code RuntimeDyldError::convertToErrorCode() const {
62 static RuntimeDyldErrorCategory RTDyldErrorCategory;
63 return std::error_code(GenericRTDyldError, RTDyldErrorCategory);
64}
65
66// Empty out-of-line virtual destructor as the key function.
67RuntimeDyldImpl::~RuntimeDyldImpl() = default;
68
69// Pin LoadedObjectInfo's vtables to this file.
70void RuntimeDyld::LoadedObjectInfo::anchor() {}
71
72namespace llvm {
73
74void RuntimeDyldImpl::registerEHFrames() {}
75
76void RuntimeDyldImpl::deregisterEHFrames() {
77 MemMgr.deregisterEHFrames();
78}
79
80#ifndef NDEBUG
81static void dumpSectionMemory(const SectionEntry &S, StringRef State) {
82 dbgs() << "----- Contents of section " << S.getName() << " " << State
83 << " -----";
84
85 if (S.getAddress() == nullptr) {
86 dbgs() << "\n <section not emitted>\n";
87 return;
88 }
89
90 const unsigned ColsPerRow = 16;
91
92 uint8_t *DataAddr = S.getAddress();
93 uint64_t LoadAddr = S.getLoadAddress();
94
95 unsigned StartPadding = LoadAddr & (ColsPerRow - 1);
96 unsigned BytesRemaining = S.getSize();
97
98 if (StartPadding) {
99 dbgs() << "\n" << format("0x%016" PRIx64,
100 LoadAddr & ~(uint64_t)(ColsPerRow - 1)) << ":";
101 while (StartPadding--)
102 dbgs() << " ";
103 }
104
105 while (BytesRemaining > 0) {
106 if ((LoadAddr & (ColsPerRow - 1)) == 0)
107 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr) << ":";
108
109 dbgs() << " " << format("%02x", *DataAddr);
110
111 ++DataAddr;
112 ++LoadAddr;
113 --BytesRemaining;
114 }
115
116 dbgs() << "\n";
117}
118#endif
119
120// Resolve the relocations for all symbols we currently know about.
121void RuntimeDyldImpl::resolveRelocations() {
122 std::lock_guard<sys::Mutex> locked(lock);
123
124 // Print out the sections prior to relocation.
125 LLVM_DEBUG({
126 for (SectionEntry &S : Sections)
127 dumpSectionMemory(S, "before relocations");
128 });
129
130 // First, resolve relocations associated with external symbols.
131 if (auto Err = resolveExternalSymbols()) {
132 HasError = true;
133 ErrorStr = toString(E: std::move(Err));
134 }
135
136 resolveLocalRelocations();
137
138 // Print out sections after relocation.
139 LLVM_DEBUG({
140 for (SectionEntry &S : Sections)
141 dumpSectionMemory(S, "after relocations");
142 });
143}
144
145void RuntimeDyldImpl::resolveLocalRelocations() {
146 // Iterate over all outstanding relocations
147 for (const auto &Rel : Relocations) {
148 // The Section here (Sections[i]) refers to the section in which the
149 // symbol for the relocation is located. The SectionID in the relocation
150 // entry provides the section to which the relocation will be applied.
151 unsigned Idx = Rel.first;
152 uint64_t Addr = getSectionLoadAddress(SectionID: Idx);
153 LLVM_DEBUG(dbgs() << "Resolving relocations Section #" << Idx << "\t"
154 << format("%p", (uintptr_t)Addr) << "\n");
155 resolveRelocationList(Relocs: Rel.second, Value: Addr);
156 }
157 Relocations.clear();
158}
159
160void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
161 uint64_t TargetAddress) {
162 std::lock_guard<sys::Mutex> locked(lock);
163 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
164 if (Sections[i].getAddress() == LocalAddress) {
165 reassignSectionAddress(SectionID: i, Addr: TargetAddress);
166 return;
167 }
168 }
169 llvm_unreachable("Attempting to remap address of unknown section!");
170}
171
172static Error getOffset(const SymbolRef &Sym, SectionRef Sec,
173 uint64_t &Result) {
174 Expected<uint64_t> AddressOrErr = Sym.getAddress();
175 if (!AddressOrErr)
176 return AddressOrErr.takeError();
177 Result = *AddressOrErr - Sec.getAddress();
178 return Error::success();
179}
180
181Expected<RuntimeDyldImpl::ObjSectionToIDMap>
182RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
183 std::lock_guard<sys::Mutex> locked(lock);
184
185 // Save information about our target
186 Arch = (Triple::ArchType)Obj.getArch();
187 IsTargetLittleEndian = Obj.isLittleEndian();
188 setMipsABI(Obj);
189
190 // Compute the memory size required to load all sections to be loaded
191 // and pass this information to the memory manager
192 if (MemMgr.needsToReserveAllocationSpace()) {
193 uint64_t CodeSize = 0, RODataSize = 0, RWDataSize = 0;
194 Align CodeAlign, RODataAlign, RWDataAlign;
195 if (auto Err = computeTotalAllocSize(Obj, CodeSize, CodeAlign, RODataSize,
196 RODataAlign, RWDataSize, RWDataAlign))
197 return std::move(Err);
198 MemMgr.reserveAllocationSpace(CodeSize, CodeAlign, RODataSize, RODataAlign,
199 RWDataSize, RWDataAlign);
200 }
201
202 // Used sections from the object file
203 ObjSectionToIDMap LocalSections;
204
205 // Common symbols requiring allocation, with their sizes and alignments
206 CommonSymbolList CommonSymbolsToAllocate;
207
208 uint64_t CommonSize = 0;
209 uint32_t CommonAlign = 0;
210
211 // First, collect all weak and common symbols. We need to know if stronger
212 // definitions occur elsewhere.
213 JITSymbolResolver::LookupSet ResponsibilitySet;
214 {
215 JITSymbolResolver::LookupSet Symbols;
216 for (auto &Sym : Obj.symbols()) {
217 Expected<uint32_t> FlagsOrErr = Sym.getFlags();
218 if (!FlagsOrErr)
219 // TODO: Test this error.
220 return FlagsOrErr.takeError();
221 if ((*FlagsOrErr & SymbolRef::SF_Common) ||
222 (*FlagsOrErr & SymbolRef::SF_Weak)) {
223 // Get symbol name.
224 if (auto NameOrErr = Sym.getName())
225 Symbols.insert(x: *NameOrErr);
226 else
227 return NameOrErr.takeError();
228 }
229 }
230
231 if (auto ResultOrErr = Resolver.getResponsibilitySet(Symbols))
232 ResponsibilitySet = std::move(*ResultOrErr);
233 else
234 return ResultOrErr.takeError();
235 }
236
237 // Parse symbols
238 LLVM_DEBUG(dbgs() << "Parse symbols:\n");
239 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
240 ++I) {
241 Expected<uint32_t> FlagsOrErr = I->getFlags();
242 if (!FlagsOrErr)
243 // TODO: Test this error.
244 return FlagsOrErr.takeError();
245
246 // Skip undefined symbols.
247 if (*FlagsOrErr & SymbolRef::SF_Undefined)
248 continue;
249
250 // Get the symbol type.
251 object::SymbolRef::Type SymType;
252 if (auto SymTypeOrErr = I->getType())
253 SymType = *SymTypeOrErr;
254 else
255 return SymTypeOrErr.takeError();
256
257 // Get symbol name.
258 StringRef Name;
259 if (auto NameOrErr = I->getName())
260 Name = *NameOrErr;
261 else
262 return NameOrErr.takeError();
263
264 // Compute JIT symbol flags.
265 auto JITSymFlags = getJITSymbolFlags(Sym: *I);
266 if (!JITSymFlags)
267 return JITSymFlags.takeError();
268
269 // If this is a weak definition, check to see if there's a strong one.
270 // If there is, skip this symbol (we won't be providing it: the strong
271 // definition will). If there's no strong definition, make this definition
272 // strong.
273 if (JITSymFlags->isWeak() || JITSymFlags->isCommon()) {
274 // First check whether there's already a definition in this instance.
275 if (GlobalSymbolTable.count(Key: Name))
276 continue;
277
278 // If we're not responsible for this symbol, skip it.
279 if (!ResponsibilitySet.count(x: Name))
280 continue;
281
282 // Otherwise update the flags on the symbol to make this definition
283 // strong.
284 if (JITSymFlags->isWeak())
285 *JITSymFlags &= ~JITSymbolFlags::Weak;
286 if (JITSymFlags->isCommon()) {
287 *JITSymFlags &= ~JITSymbolFlags::Common;
288 uint32_t Align = I->getAlignment();
289 uint64_t Size = I->getCommonSize();
290 if (!CommonAlign)
291 CommonAlign = Align;
292 CommonSize = alignTo(Value: CommonSize, Align) + Size;
293 CommonSymbolsToAllocate.push_back(x: *I);
294 }
295 }
296
297 if (*FlagsOrErr & SymbolRef::SF_Absolute &&
298 SymType != object::SymbolRef::ST_File) {
299 uint64_t Addr = 0;
300 if (auto AddrOrErr = I->getAddress())
301 Addr = *AddrOrErr;
302 else
303 return AddrOrErr.takeError();
304
305 unsigned SectionID = AbsoluteSymbolSection;
306
307 LLVM_DEBUG(dbgs() << "\tType: " << SymType << " (absolute) Name: " << Name
308 << " SID: " << SectionID
309 << " Offset: " << format("%p", (uintptr_t)Addr)
310 << " flags: " << *FlagsOrErr << "\n");
311 // Skip absolute symbol relocations.
312 if (!Name.empty()) {
313 auto Result = GlobalSymbolTable.insert_or_assign(
314 Key: Name, Val: SymbolTableEntry(SectionID, Addr, *JITSymFlags));
315 processNewSymbol(ObjSymbol: *I, Entry&: Result.first->getValue());
316 }
317 } else if (SymType == object::SymbolRef::ST_Function ||
318 SymType == object::SymbolRef::ST_Data ||
319 SymType == object::SymbolRef::ST_Unknown ||
320 SymType == object::SymbolRef::ST_Other) {
321
322 section_iterator SI = Obj.section_end();
323 if (auto SIOrErr = I->getSection())
324 SI = *SIOrErr;
325 else
326 return SIOrErr.takeError();
327
328 if (SI == Obj.section_end())
329 continue;
330
331 // Get symbol offset.
332 uint64_t SectOffset;
333 if (auto Err = getOffset(Sym: *I, Sec: *SI, Result&: SectOffset))
334 return std::move(Err);
335
336 bool IsCode = SI->isText();
337 unsigned SectionID;
338 if (auto SectionIDOrErr =
339 findOrEmitSection(Obj, Section: *SI, IsCode, LocalSections))
340 SectionID = *SectionIDOrErr;
341 else
342 return SectionIDOrErr.takeError();
343
344 LLVM_DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
345 << " SID: " << SectionID
346 << " Offset: " << format("%p", (uintptr_t)SectOffset)
347 << " flags: " << *FlagsOrErr << "\n");
348 // Skip absolute symbol relocations.
349 if (!Name.empty()) {
350 auto Result = GlobalSymbolTable.insert_or_assign(
351 Key: Name, Val: SymbolTableEntry(SectionID, SectOffset, *JITSymFlags));
352 processNewSymbol(ObjSymbol: *I, Entry&: Result.first->getValue());
353 }
354 }
355 }
356
357 // Allocate common symbols
358 if (auto Err = emitCommonSymbols(Obj, CommonSymbols&: CommonSymbolsToAllocate, CommonSize,
359 CommonAlign))
360 return std::move(Err);
361
362 // Parse and process relocations
363 LLVM_DEBUG(dbgs() << "Parse relocations:\n");
364 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
365 SI != SE; ++SI) {
366 StubMap Stubs;
367
368 Expected<section_iterator> RelSecOrErr = SI->getRelocatedSection();
369 if (!RelSecOrErr)
370 return RelSecOrErr.takeError();
371
372 section_iterator RelocatedSection = *RelSecOrErr;
373 if (RelocatedSection == SE)
374 continue;
375
376 relocation_iterator I = SI->relocation_begin();
377 relocation_iterator E = SI->relocation_end();
378
379 if (I == E && !ProcessAllSections)
380 continue;
381
382 bool IsCode = RelocatedSection->isText();
383 unsigned SectionID = 0;
384 if (auto SectionIDOrErr = findOrEmitSection(Obj, Section: *RelocatedSection, IsCode,
385 LocalSections))
386 SectionID = *SectionIDOrErr;
387 else
388 return SectionIDOrErr.takeError();
389
390 LLVM_DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
391
392 for (; I != E;)
393 if (auto IOrErr = processRelocationRef(SectionID, RelI: I, Obj, ObjSectionToID&: LocalSections, Stubs))
394 I = *IOrErr;
395 else
396 return IOrErr.takeError();
397
398 // If there is a NotifyStubEmitted callback set, call it to register any
399 // stubs created for this section.
400 if (NotifyStubEmitted) {
401 StringRef FileName = Obj.getFileName();
402 StringRef SectionName = Sections[SectionID].getName();
403 for (auto &KV : Stubs) {
404
405 auto &VR = KV.first;
406 uint64_t StubAddr = KV.second;
407
408 // If this is a named stub, just call NotifyStubEmitted.
409 if (VR.SymbolName) {
410 NotifyStubEmitted(FileName, SectionName, VR.SymbolName, SectionID,
411 StubAddr);
412 continue;
413 }
414
415 // Otherwise we will have to try a reverse lookup on the globla symbol table.
416 for (auto &GSTMapEntry : GlobalSymbolTable) {
417 StringRef SymbolName = GSTMapEntry.first();
418 auto &GSTEntry = GSTMapEntry.second;
419 if (GSTEntry.getSectionID() == VR.SectionID &&
420 GSTEntry.getOffset() == VR.Offset) {
421 NotifyStubEmitted(FileName, SectionName, SymbolName, SectionID,
422 StubAddr);
423 break;
424 }
425 }
426 }
427 }
428 }
429
430 // Process remaining sections
431 if (ProcessAllSections) {
432 LLVM_DEBUG(dbgs() << "Process remaining sections:\n");
433 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
434 SI != SE; ++SI) {
435
436 /* Ignore already loaded sections */
437 if (LocalSections.find(x: *SI) != LocalSections.end())
438 continue;
439
440 bool IsCode = SI->isText();
441 if (auto SectionIDOrErr =
442 findOrEmitSection(Obj, Section: *SI, IsCode, LocalSections))
443 LLVM_DEBUG(dbgs() << "\tSectionID: " << (*SectionIDOrErr) << "\n");
444 else
445 return SectionIDOrErr.takeError();
446 }
447 }
448
449 // Give the subclasses a chance to tie-up any loose ends.
450 if (auto Err = finalizeLoad(ObjImg: Obj, SectionMap&: LocalSections))
451 return std::move(Err);
452
453// for (auto E : LocalSections)
454// llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
455
456 return LocalSections;
457}
458
459// A helper method for computeTotalAllocSize.
460// Computes the memory size required to allocate sections with the given sizes,
461// assuming that all sections are allocated with the given alignment
462static uint64_t
463computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
464 Align Alignment) {
465 uint64_t TotalSize = 0;
466 for (uint64_t SectionSize : SectionSizes)
467 TotalSize += alignTo(Size: SectionSize, A: Alignment);
468 return TotalSize;
469}
470
471static bool isRequiredForExecution(const SectionRef Section) {
472 const ObjectFile *Obj = Section.getObject();
473 if (isa<object::ELFObjectFileBase>(Val: Obj))
474 return ELFSectionRef(Section).getFlags() & ELF::SHF_ALLOC;
475 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Val: Obj)) {
476 const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
477 // Avoid loading zero-sized COFF sections.
478 // In PE files, VirtualSize gives the section size, and SizeOfRawData
479 // may be zero for sections with content. In Obj files, SizeOfRawData
480 // gives the section size, and VirtualSize is always zero. Hence
481 // the need to check for both cases below.
482 bool HasContent =
483 (CoffSection->VirtualSize > 0) || (CoffSection->SizeOfRawData > 0);
484 bool IsDiscardable =
485 CoffSection->Characteristics &
486 (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
487 return HasContent && !IsDiscardable;
488 }
489
490 assert(isa<MachOObjectFile>(Obj));
491 return true;
492}
493
494static bool isReadOnlyData(const SectionRef Section) {
495 const ObjectFile *Obj = Section.getObject();
496 if (isa<object::ELFObjectFileBase>(Val: Obj))
497 return !(ELFSectionRef(Section).getFlags() &
498 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
499 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Val: Obj))
500 return ((COFFObj->getCOFFSection(Section)->Characteristics &
501 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
502 | COFF::IMAGE_SCN_MEM_READ
503 | COFF::IMAGE_SCN_MEM_WRITE))
504 ==
505 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
506 | COFF::IMAGE_SCN_MEM_READ));
507
508 assert(isa<MachOObjectFile>(Obj));
509 return false;
510}
511
512static bool isZeroInit(const SectionRef Section) {
513 const ObjectFile *Obj = Section.getObject();
514 if (isa<object::ELFObjectFileBase>(Val: Obj))
515 return ELFSectionRef(Section).getType() == ELF::SHT_NOBITS;
516 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Val: Obj))
517 return COFFObj->getCOFFSection(Section)->Characteristics &
518 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
519
520 auto *MachO = cast<MachOObjectFile>(Val: Obj);
521 unsigned SectionType = MachO->getSectionType(Sec: Section);
522 return SectionType == MachO::S_ZEROFILL ||
523 SectionType == MachO::S_GB_ZEROFILL;
524}
525
526static bool isTLS(const SectionRef Section) {
527 const ObjectFile *Obj = Section.getObject();
528 if (isa<object::ELFObjectFileBase>(Val: Obj))
529 return ELFSectionRef(Section).getFlags() & ELF::SHF_TLS;
530 return false;
531}
532
533// Compute an upper bound of the memory size that is required to load all
534// sections
535Error RuntimeDyldImpl::computeTotalAllocSize(
536 const ObjectFile &Obj, uint64_t &CodeSize, Align &CodeAlign,
537 uint64_t &RODataSize, Align &RODataAlign, uint64_t &RWDataSize,
538 Align &RWDataAlign) {
539 // Compute the size of all sections required for execution
540 std::vector<uint64_t> CodeSectionSizes;
541 std::vector<uint64_t> ROSectionSizes;
542 std::vector<uint64_t> RWSectionSizes;
543
544 // Collect sizes of all sections to be loaded;
545 // also determine the max alignment of all sections
546 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
547 SI != SE; ++SI) {
548 const SectionRef &Section = *SI;
549
550 bool IsRequired = isRequiredForExecution(Section) || ProcessAllSections;
551
552 // Consider only the sections that are required to be loaded for execution
553 if (IsRequired) {
554 uint64_t DataSize = Section.getSize();
555 Align Alignment = Section.getAlignment();
556 bool IsCode = Section.isText();
557 bool IsReadOnly = isReadOnlyData(Section);
558 bool IsTLS = isTLS(Section);
559
560 Expected<StringRef> NameOrErr = Section.getName();
561 if (!NameOrErr)
562 return NameOrErr.takeError();
563 StringRef Name = *NameOrErr;
564
565 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
566
567 uint64_t PaddingSize = 0;
568 if (Name == ".eh_frame")
569 PaddingSize += 4;
570 if (StubBufSize != 0)
571 PaddingSize += getStubAlignment().value() - 1;
572
573 uint64_t SectionSize = DataSize + PaddingSize + StubBufSize;
574
575 // The .eh_frame section (at least on Linux) needs an extra four bytes
576 // padded
577 // with zeroes added at the end. For MachO objects, this section has a
578 // slightly different name, so this won't have any effect for MachO
579 // objects.
580 if (Name == ".eh_frame")
581 SectionSize += 4;
582
583 if (!SectionSize)
584 SectionSize = 1;
585
586 if (IsCode) {
587 CodeAlign = std::max(a: CodeAlign, b: Alignment);
588 CodeSectionSizes.push_back(x: SectionSize);
589 } else if (IsReadOnly) {
590 RODataAlign = std::max(a: RODataAlign, b: Alignment);
591 ROSectionSizes.push_back(x: SectionSize);
592 } else if (!IsTLS) {
593 RWDataAlign = std::max(a: RWDataAlign, b: Alignment);
594 RWSectionSizes.push_back(x: SectionSize);
595 }
596 }
597 }
598
599 // Compute Global Offset Table size. If it is not zero we
600 // also update alignment, which is equal to a size of a
601 // single GOT entry.
602 if (unsigned GotSize = computeGOTSize(Obj)) {
603 RWSectionSizes.push_back(x: GotSize);
604 RWDataAlign = std::max(a: RWDataAlign, b: Align(getGOTEntrySize()));
605 }
606
607 // Compute the size of all common symbols
608 uint64_t CommonSize = 0;
609 Align CommonAlign;
610 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
611 ++I) {
612 Expected<uint32_t> FlagsOrErr = I->getFlags();
613 if (!FlagsOrErr)
614 // TODO: Test this error.
615 return FlagsOrErr.takeError();
616 if (*FlagsOrErr & SymbolRef::SF_Common) {
617 // Add the common symbols to a list. We'll allocate them all below.
618 uint64_t Size = I->getCommonSize();
619 Align Alignment = Align(I->getAlignment());
620 // If this is the first common symbol, use its alignment as the alignment
621 // for the common symbols section.
622 if (CommonSize == 0)
623 CommonAlign = Alignment;
624 CommonSize = alignTo(Size: CommonSize, A: Alignment) + Size;
625 }
626 }
627 if (CommonSize != 0) {
628 RWSectionSizes.push_back(x: CommonSize);
629 RWDataAlign = std::max(a: RWDataAlign, b: CommonAlign);
630 }
631
632 if (!CodeSectionSizes.empty()) {
633 // Add 64 bytes for a potential IFunc resolver stub
634 CodeSectionSizes.push_back(x: 64);
635 }
636
637 // Compute the required allocation space for each different type of sections
638 // (code, read-only data, read-write data) assuming that all sections are
639 // allocated with the max alignment. Note that we cannot compute with the
640 // individual alignments of the sections, because then the required size
641 // depends on the order, in which the sections are allocated.
642 CodeSize = computeAllocationSizeForSections(SectionSizes&: CodeSectionSizes, Alignment: CodeAlign);
643 RODataSize = computeAllocationSizeForSections(SectionSizes&: ROSectionSizes, Alignment: RODataAlign);
644 RWDataSize = computeAllocationSizeForSections(SectionSizes&: RWSectionSizes, Alignment: RWDataAlign);
645
646 return Error::success();
647}
648
649// compute GOT size
650unsigned RuntimeDyldImpl::computeGOTSize(const ObjectFile &Obj) {
651 size_t GotEntrySize = getGOTEntrySize();
652 if (!GotEntrySize)
653 return 0;
654
655 size_t GotSize = 0;
656 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
657 SI != SE; ++SI) {
658
659 for (const RelocationRef &Reloc : SI->relocations())
660 if (relocationNeedsGot(R: Reloc))
661 GotSize += GotEntrySize;
662 }
663
664 return GotSize;
665}
666
667// compute stub buffer size for the given section
668unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
669 const SectionRef &Section) {
670 if (!MemMgr.allowStubAllocation()) {
671 return 0;
672 }
673
674 unsigned StubSize = getMaxStubSize();
675 if (StubSize == 0) {
676 return 0;
677 }
678 // FIXME: this is an inefficient way to handle this. We should computed the
679 // necessary section allocation size in loadObject by walking all the sections
680 // once.
681 unsigned StubBufSize = 0;
682 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
683 SI != SE; ++SI) {
684
685 Expected<section_iterator> RelSecOrErr = SI->getRelocatedSection();
686 if (!RelSecOrErr)
687 report_fatal_error(reason: Twine(toString(E: RelSecOrErr.takeError())));
688
689 section_iterator RelSecI = *RelSecOrErr;
690 if (!(RelSecI == Section))
691 continue;
692
693 for (const RelocationRef &Reloc : SI->relocations()) {
694 if (relocationNeedsStub(R: Reloc))
695 StubBufSize += StubSize;
696 if (relocationNeedsDLLImportStub(R: Reloc))
697 StubBufSize = sizeAfterAddingDLLImportStub(Size: StubBufSize);
698 }
699 }
700
701 // Get section data size and alignment
702 uint64_t DataSize = Section.getSize();
703 Align Alignment = Section.getAlignment();
704
705 // Add stubbuf size alignment
706 Align StubAlignment = getStubAlignment();
707 Align EndAlignment = commonAlignment(A: Alignment, Offset: DataSize);
708 if (StubAlignment > EndAlignment)
709 StubBufSize += StubAlignment.value() - EndAlignment.value();
710 return StubBufSize;
711}
712
713uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
714 unsigned Size) const {
715 uint64_t Result = 0;
716 if (IsTargetLittleEndian) {
717 Src += Size - 1;
718 while (Size--)
719 Result = (Result << 8) | *Src--;
720 } else
721 while (Size--)
722 Result = (Result << 8) | *Src++;
723
724 return Result;
725}
726
727void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
728 unsigned Size) const {
729 if (IsTargetLittleEndian) {
730 while (Size--) {
731 *Dst++ = Value & 0xFF;
732 Value >>= 8;
733 }
734 } else {
735 Dst += Size - 1;
736 while (Size--) {
737 *Dst-- = Value & 0xFF;
738 Value >>= 8;
739 }
740 }
741}
742
743Expected<JITSymbolFlags>
744RuntimeDyldImpl::getJITSymbolFlags(const SymbolRef &SR) {
745 return JITSymbolFlags::fromObjectSymbol(Symbol: SR);
746}
747
748Error RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
749 CommonSymbolList &SymbolsToAllocate,
750 uint64_t CommonSize,
751 uint32_t CommonAlign) {
752 if (SymbolsToAllocate.empty())
753 return Error::success();
754
755 // Allocate memory for the section
756 unsigned SectionID = Sections.size();
757 uint8_t *Addr = MemMgr.allocateDataSection(Size: CommonSize, Alignment: CommonAlign, SectionID,
758 SectionName: "<common symbols>", IsReadOnly: false);
759 if (!Addr)
760 report_fatal_error(reason: "Unable to allocate memory for common symbols!");
761 uint64_t Offset = 0;
762 Sections.push_back(
763 x: SectionEntry("<common symbols>", Addr, CommonSize, CommonSize, 0));
764 memset(s: Addr, c: 0, n: CommonSize);
765
766 LLVM_DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID
767 << " new addr: " << format("%p", Addr)
768 << " DataSize: " << CommonSize << "\n");
769
770 // Assign the address of each symbol
771 for (auto &Sym : SymbolsToAllocate) {
772 uint32_t Alignment = Sym.getAlignment();
773 uint64_t Size = Sym.getCommonSize();
774 StringRef Name;
775 if (auto NameOrErr = Sym.getName())
776 Name = *NameOrErr;
777 else
778 return NameOrErr.takeError();
779 if (Alignment) {
780 // This symbol has an alignment requirement.
781 uint64_t AlignOffset =
782 offsetToAlignment(Value: (uint64_t)Addr, Alignment: Align(Alignment));
783 Addr += AlignOffset;
784 Offset += AlignOffset;
785 }
786 auto JITSymFlags = getJITSymbolFlags(SR: Sym);
787
788 if (!JITSymFlags)
789 return JITSymFlags.takeError();
790
791 LLVM_DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
792 << format("%p", Addr) << "\n");
793 if (!Name.empty()) // Skip absolute symbol relocations.
794 GlobalSymbolTable[Name] =
795 SymbolTableEntry(SectionID, Offset, std::move(*JITSymFlags));
796 Offset += Size;
797 Addr += Size;
798 }
799
800 return Error::success();
801}
802
803Expected<unsigned>
804RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
805 const SectionRef &Section,
806 bool IsCode) {
807 StringRef data;
808 Align Alignment = Section.getAlignment();
809
810 unsigned PaddingSize = 0;
811 unsigned StubBufSize = 0;
812 bool IsRequired = isRequiredForExecution(Section);
813 bool IsVirtual = Section.isVirtual();
814 bool IsZeroInit = isZeroInit(Section);
815 bool IsReadOnly = isReadOnlyData(Section);
816 bool IsTLS = isTLS(Section);
817 uint64_t DataSize = Section.getSize();
818
819 Expected<StringRef> NameOrErr = Section.getName();
820 if (!NameOrErr)
821 return NameOrErr.takeError();
822 StringRef Name = *NameOrErr;
823
824 StubBufSize = computeSectionStubBufSize(Obj, Section);
825
826 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
827 // with zeroes added at the end. For MachO objects, this section has a
828 // slightly different name, so this won't have any effect for MachO objects.
829 if (Name == ".eh_frame")
830 PaddingSize = 4;
831
832 uintptr_t Allocate;
833 unsigned SectionID = Sections.size();
834 uint8_t *Addr;
835 uint64_t LoadAddress = 0;
836 const char *pData = nullptr;
837
838 // If this section contains any bits (i.e. isn't a virtual or bss section),
839 // grab a reference to them.
840 if (!IsVirtual && !IsZeroInit) {
841 // In either case, set the location of the unrelocated section in memory,
842 // since we still process relocations for it even if we're not applying them.
843 if (Expected<StringRef> E = Section.getContents())
844 data = *E;
845 else
846 return E.takeError();
847 pData = data.data();
848 }
849
850 // If there are any stubs then the section alignment needs to be at least as
851 // high as stub alignment or padding calculations may by incorrect when the
852 // section is remapped.
853 if (StubBufSize != 0) {
854 Alignment = std::max(a: Alignment, b: getStubAlignment());
855 PaddingSize += getStubAlignment().value() - 1;
856 }
857
858 // Some sections, such as debug info, don't need to be loaded for execution.
859 // Process those only if explicitly requested.
860 if (IsRequired || ProcessAllSections) {
861 Allocate = DataSize + PaddingSize + StubBufSize;
862 if (!Allocate)
863 Allocate = 1;
864 if (IsTLS) {
865 auto TLSSection = MemMgr.allocateTLSSection(Size: Allocate, Alignment: Alignment.value(),
866 SectionID, SectionName: Name);
867 Addr = TLSSection.InitializationImage;
868 LoadAddress = TLSSection.Offset;
869 } else if (IsCode) {
870 Addr = MemMgr.allocateCodeSection(Size: Allocate, Alignment: Alignment.value(), SectionID,
871 SectionName: Name);
872 } else {
873 Addr = MemMgr.allocateDataSection(Size: Allocate, Alignment: Alignment.value(), SectionID,
874 SectionName: Name, IsReadOnly);
875 }
876 if (!Addr)
877 report_fatal_error(reason: "Unable to allocate section memory!");
878
879 // Zero-initialize or copy the data from the image
880 if (IsZeroInit || IsVirtual)
881 memset(s: Addr, c: 0, n: DataSize);
882 else
883 memcpy(dest: Addr, src: pData, n: DataSize);
884
885 // Fill in any extra bytes we allocated for padding
886 if (PaddingSize != 0) {
887 memset(s: Addr + DataSize, c: 0, n: PaddingSize);
888 // Update the DataSize variable to include padding.
889 DataSize += PaddingSize;
890
891 // Align DataSize to stub alignment if we have any stubs (PaddingSize will
892 // have been increased above to account for this).
893 if (StubBufSize > 0)
894 DataSize &= -(uint64_t)getStubAlignment().value();
895 }
896
897 LLVM_DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: "
898 << Name << " obj addr: " << format("%p", pData)
899 << " new addr: " << format("%p", Addr) << " DataSize: "
900 << DataSize << " StubBufSize: " << StubBufSize
901 << " Allocate: " << Allocate << "\n");
902 } else {
903 // Even if we didn't load the section, we need to record an entry for it
904 // to handle later processing (and by 'handle' I mean don't do anything
905 // with these sections).
906 Allocate = 0;
907 Addr = nullptr;
908 LLVM_DEBUG(
909 dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
910 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
911 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
912 << " Allocate: " << Allocate << "\n");
913 }
914
915 Sections.push_back(
916 x: SectionEntry(Name, Addr, DataSize, Allocate, (uintptr_t)pData));
917
918 // The load address of a TLS section is not equal to the address of its
919 // initialization image
920 if (IsTLS)
921 Sections.back().setLoadAddress(LoadAddress);
922 // Debug info sections are linked as if their load address was zero
923 if (!IsRequired)
924 Sections.back().setLoadAddress(0);
925
926 return SectionID;
927}
928
929Expected<unsigned>
930RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
931 const SectionRef &Section,
932 bool IsCode,
933 ObjSectionToIDMap &LocalSections) {
934
935 unsigned SectionID = 0;
936 ObjSectionToIDMap::iterator i = LocalSections.find(x: Section);
937 if (i != LocalSections.end())
938 SectionID = i->second;
939 else {
940 if (auto SectionIDOrErr = emitSection(Obj, Section, IsCode))
941 SectionID = *SectionIDOrErr;
942 else
943 return SectionIDOrErr.takeError();
944 LocalSections[Section] = SectionID;
945 }
946 return SectionID;
947}
948
949void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
950 unsigned SectionID) {
951 Relocations[SectionID].push_back(Elt: RE);
952}
953
954void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
955 StringRef SymbolName) {
956 // Relocation by symbol. If the symbol is found in the global symbol table,
957 // create an appropriate section relocation. Otherwise, add it to
958 // ExternalSymbolRelocations.
959 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Key: SymbolName);
960 if (Loc == GlobalSymbolTable.end()) {
961 ExternalSymbolRelocations[SymbolName].push_back(Elt: RE);
962 } else {
963 assert(!SymbolName.empty() &&
964 "Empty symbol should not be in GlobalSymbolTable");
965 // Copy the RE since we want to modify its addend.
966 RelocationEntry RECopy = RE;
967 const auto &SymInfo = Loc->second;
968 RECopy.Addend += SymInfo.getOffset();
969 Relocations[SymInfo.getSectionID()].push_back(Elt: RECopy);
970 }
971}
972
973uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
974 unsigned AbiVariant) {
975 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be ||
976 Arch == Triple::aarch64_32) {
977 // This stub has to be able to access the full address space,
978 // since symbol lookup won't necessarily find a handy, in-range,
979 // PLT stub for functions which could be anywhere.
980 // Stub can use ip0 (== x16) to calculate address
981 writeBytesUnaligned(Value: 0xd2e00010, Dst: Addr, Size: 4); // movz ip0, #:abs_g3:<addr>
982 writeBytesUnaligned(Value: 0xf2c00010, Dst: Addr+4, Size: 4); // movk ip0, #:abs_g2_nc:<addr>
983 writeBytesUnaligned(Value: 0xf2a00010, Dst: Addr+8, Size: 4); // movk ip0, #:abs_g1_nc:<addr>
984 writeBytesUnaligned(Value: 0xf2800010, Dst: Addr+12, Size: 4); // movk ip0, #:abs_g0_nc:<addr>
985 writeBytesUnaligned(Value: 0xd61f0200, Dst: Addr+16, Size: 4); // br ip0
986
987 return Addr;
988 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
989 // TODO: There is only ARM far stub now. We should add the Thumb stub,
990 // and stubs for branches Thumb - ARM and ARM - Thumb.
991 writeBytesUnaligned(Value: 0xe51ff004, Dst: Addr, Size: 4); // ldr pc, [pc, #-4]
992 return Addr + 4;
993 } else if (Arch == Triple::loongarch64) {
994 // lu12i.w $t0, %abs_hi20(addr)
995 // ori $t0, $t0, %abs_lo12(addr)
996 // lu32i.d $t0, %abs64_lo20(addr)
997 // lu52i.d $t0, $t0, %abs64_lo12(addr)
998 // jr $t0
999 writeBytesUnaligned(Value: 0x1400000c, Dst: Addr, Size: 4);
1000 writeBytesUnaligned(Value: 0x0380018c, Dst: Addr + 4, Size: 4);
1001 writeBytesUnaligned(Value: 0x1600000c, Dst: Addr + 8, Size: 4);
1002 writeBytesUnaligned(Value: 0x0300018c, Dst: Addr + 12, Size: 4);
1003 writeBytesUnaligned(Value: 0x4c000180, Dst: Addr + 16, Size: 4);
1004 return Addr;
1005 } else if (IsMipsO32ABI || IsMipsN32ABI) {
1006 // 0: 3c190000 lui t9,%hi(addr).
1007 // 4: 27390000 addiu t9,t9,%lo(addr).
1008 // 8: 03200008 jr t9.
1009 // c: 00000000 nop.
1010 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
1011 const unsigned NopInstr = 0x0;
1012 unsigned JrT9Instr = 0x03200008;
1013 if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_32R6 ||
1014 (AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
1015 JrT9Instr = 0x03200009;
1016
1017 writeBytesUnaligned(Value: LuiT9Instr, Dst: Addr, Size: 4);
1018 writeBytesUnaligned(Value: AdduiT9Instr, Dst: Addr + 4, Size: 4);
1019 writeBytesUnaligned(Value: JrT9Instr, Dst: Addr + 8, Size: 4);
1020 writeBytesUnaligned(Value: NopInstr, Dst: Addr + 12, Size: 4);
1021 return Addr;
1022 } else if (IsMipsN64ABI) {
1023 // 0: 3c190000 lui t9,%highest(addr).
1024 // 4: 67390000 daddiu t9,t9,%higher(addr).
1025 // 8: 0019CC38 dsll t9,t9,16.
1026 // c: 67390000 daddiu t9,t9,%hi(addr).
1027 // 10: 0019CC38 dsll t9,t9,16.
1028 // 14: 67390000 daddiu t9,t9,%lo(addr).
1029 // 18: 03200008 jr t9.
1030 // 1c: 00000000 nop.
1031 const unsigned LuiT9Instr = 0x3c190000, DaddiuT9Instr = 0x67390000,
1032 DsllT9Instr = 0x19CC38;
1033 const unsigned NopInstr = 0x0;
1034 unsigned JrT9Instr = 0x03200008;
1035 if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
1036 JrT9Instr = 0x03200009;
1037
1038 writeBytesUnaligned(Value: LuiT9Instr, Dst: Addr, Size: 4);
1039 writeBytesUnaligned(Value: DaddiuT9Instr, Dst: Addr + 4, Size: 4);
1040 writeBytesUnaligned(Value: DsllT9Instr, Dst: Addr + 8, Size: 4);
1041 writeBytesUnaligned(Value: DaddiuT9Instr, Dst: Addr + 12, Size: 4);
1042 writeBytesUnaligned(Value: DsllT9Instr, Dst: Addr + 16, Size: 4);
1043 writeBytesUnaligned(Value: DaddiuT9Instr, Dst: Addr + 20, Size: 4);
1044 writeBytesUnaligned(Value: JrT9Instr, Dst: Addr + 24, Size: 4);
1045 writeBytesUnaligned(Value: NopInstr, Dst: Addr + 28, Size: 4);
1046 return Addr;
1047 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
1048 // Depending on which version of the ELF ABI is in use, we need to
1049 // generate one of two variants of the stub. They both start with
1050 // the same sequence to load the target address into r12.
1051 writeInt32BE(Addr, Value: 0x3D800000); // lis r12, highest(addr)
1052 writeInt32BE(Addr: Addr+4, Value: 0x618C0000); // ori r12, higher(addr)
1053 writeInt32BE(Addr: Addr+8, Value: 0x798C07C6); // sldi r12, r12, 32
1054 writeInt32BE(Addr: Addr+12, Value: 0x658C0000); // oris r12, r12, h(addr)
1055 writeInt32BE(Addr: Addr+16, Value: 0x618C0000); // ori r12, r12, l(addr)
1056 if (AbiVariant == 2) {
1057 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
1058 // The address is already in r12 as required by the ABI. Branch to it.
1059 writeInt32BE(Addr: Addr+20, Value: 0xF8410018); // std r2, 24(r1)
1060 writeInt32BE(Addr: Addr+24, Value: 0x7D8903A6); // mtctr r12
1061 writeInt32BE(Addr: Addr+28, Value: 0x4E800420); // bctr
1062 } else {
1063 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
1064 // Load the function address on r11 and sets it to control register. Also
1065 // loads the function TOC in r2 and environment pointer to r11.
1066 writeInt32BE(Addr: Addr+20, Value: 0xF8410028); // std r2, 40(r1)
1067 writeInt32BE(Addr: Addr+24, Value: 0xE96C0000); // ld r11, 0(r12)
1068 writeInt32BE(Addr: Addr+28, Value: 0xE84C0008); // ld r2, 0(r12)
1069 writeInt32BE(Addr: Addr+32, Value: 0x7D6903A6); // mtctr r11
1070 writeInt32BE(Addr: Addr+36, Value: 0xE96C0010); // ld r11, 16(r2)
1071 writeInt32BE(Addr: Addr+40, Value: 0x4E800420); // bctr
1072 }
1073 return Addr;
1074 } else if (Arch == Triple::systemz) {
1075 writeInt16BE(Addr, Value: 0xC418); // lgrl %r1,.+8
1076 writeInt16BE(Addr: Addr+2, Value: 0x0000);
1077 writeInt16BE(Addr: Addr+4, Value: 0x0004);
1078 writeInt16BE(Addr: Addr+6, Value: 0x07F1); // brc 15,%r1
1079 // 8-byte address stored at Addr + 8
1080 return Addr;
1081 } else if (Arch == Triple::x86_64) {
1082 *Addr = 0xFF; // jmp
1083 *(Addr+1) = 0x25; // rip
1084 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
1085 } else if (Arch == Triple::x86) {
1086 *Addr = 0xE9; // 32-bit pc-relative jump.
1087 }
1088 return Addr;
1089}
1090
1091// Assign an address to a symbol name and resolve all the relocations
1092// associated with it.
1093void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
1094 uint64_t Addr) {
1095 // The address to use for relocation resolution is not
1096 // the address of the local section buffer. We must be doing
1097 // a remote execution environment of some sort. Relocations can't
1098 // be applied until all the sections have been moved. The client must
1099 // trigger this with a call to MCJIT::finalize() or
1100 // RuntimeDyld::resolveRelocations().
1101 //
1102 // Addr is a uint64_t because we can't assume the pointer width
1103 // of the target is the same as that of the host. Just use a generic
1104 // "big enough" type.
1105 LLVM_DEBUG(
1106 dbgs() << "Reassigning address for section " << SectionID << " ("
1107 << Sections[SectionID].getName() << "): "
1108 << format("0x%016" PRIx64, Sections[SectionID].getLoadAddress())
1109 << " -> " << format("0x%016" PRIx64, Addr) << "\n");
1110 Sections[SectionID].setLoadAddress(Addr);
1111}
1112
1113void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
1114 uint64_t Value) {
1115 for (const RelocationEntry &RE : Relocs) {
1116 // Ignore relocations for sections that were not loaded
1117 if (RE.SectionID != AbsoluteSymbolSection &&
1118 Sections[RE.SectionID].getAddress() == nullptr)
1119 continue;
1120 resolveRelocation(RE, Value);
1121 }
1122}
1123
1124void RuntimeDyldImpl::applyExternalSymbolRelocations(
1125 const StringMap<JITEvaluatedSymbol> ExternalSymbolMap) {
1126 for (auto &RelocKV : ExternalSymbolRelocations) {
1127 StringRef Name = RelocKV.first();
1128 RelocationList &Relocs = RelocKV.second;
1129 if (Name.size() == 0) {
1130 // This is an absolute symbol, use an address of zero.
1131 LLVM_DEBUG(dbgs() << "Resolving absolute relocations."
1132 << "\n");
1133 resolveRelocationList(Relocs, Value: 0);
1134 } else {
1135 uint64_t Addr = 0;
1136 JITSymbolFlags Flags;
1137 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Key: Name);
1138 if (Loc == GlobalSymbolTable.end()) {
1139 auto RRI = ExternalSymbolMap.find(Key: Name);
1140 assert(RRI != ExternalSymbolMap.end() && "No result for symbol");
1141 Addr = RRI->second.getAddress();
1142 Flags = RRI->second.getFlags();
1143 } else {
1144 // We found the symbol in our global table. It was probably in a
1145 // Module that we loaded previously.
1146 const auto &SymInfo = Loc->second;
1147 Addr = getSectionLoadAddress(SectionID: SymInfo.getSectionID()) +
1148 SymInfo.getOffset();
1149 Flags = SymInfo.getFlags();
1150 }
1151
1152 // FIXME: Implement error handling that doesn't kill the host program!
1153 if (!Addr && !Resolver.allowsZeroSymbols())
1154 report_fatal_error(reason: Twine("Program used external function '") + Name +
1155 "' which could not be resolved!");
1156
1157 // If Resolver returned UINT64_MAX, the client wants to handle this symbol
1158 // manually and we shouldn't resolve its relocations.
1159 if (Addr != UINT64_MAX) {
1160
1161 // Tweak the address based on the symbol flags if necessary.
1162 // For example, this is used by RuntimeDyldMachOARM to toggle the low bit
1163 // if the target symbol is Thumb.
1164 Addr = modifyAddressBasedOnFlags(Addr, Flags);
1165
1166 LLVM_DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
1167 << format("0x%lx", Addr) << "\n");
1168 resolveRelocationList(Relocs, Value: Addr);
1169 }
1170 }
1171 }
1172 ExternalSymbolRelocations.clear();
1173}
1174
1175Error RuntimeDyldImpl::resolveExternalSymbols() {
1176 StringMap<JITEvaluatedSymbol> ExternalSymbolMap;
1177
1178 // Resolution can trigger emission of more symbols, so iterate until
1179 // we've resolved *everything*.
1180 {
1181 JITSymbolResolver::LookupSet ResolvedSymbols;
1182
1183 while (true) {
1184 JITSymbolResolver::LookupSet NewSymbols;
1185
1186 for (auto &RelocKV : ExternalSymbolRelocations) {
1187 StringRef Name = RelocKV.first();
1188 if (!Name.empty() && !GlobalSymbolTable.count(Key: Name) &&
1189 !ResolvedSymbols.count(x: Name))
1190 NewSymbols.insert(x: Name);
1191 }
1192
1193 if (NewSymbols.empty())
1194 break;
1195
1196#ifdef _MSC_VER
1197 using ExpectedLookupResult =
1198 MSVCPExpected<JITSymbolResolver::LookupResult>;
1199#else
1200 using ExpectedLookupResult = Expected<JITSymbolResolver::LookupResult>;
1201#endif
1202
1203 auto NewSymbolsP = std::make_shared<std::promise<ExpectedLookupResult>>();
1204 auto NewSymbolsF = NewSymbolsP->get_future();
1205 Resolver.lookup(Symbols: NewSymbols,
1206 OnResolved: [=](Expected<JITSymbolResolver::LookupResult> Result) {
1207 NewSymbolsP->set_value(std::move(Result));
1208 });
1209
1210 auto NewResolverResults = NewSymbolsF.get();
1211
1212 if (!NewResolverResults)
1213 return NewResolverResults.takeError();
1214
1215 assert(NewResolverResults->size() == NewSymbols.size() &&
1216 "Should have errored on unresolved symbols");
1217
1218 for (auto &RRKV : *NewResolverResults) {
1219 assert(!ResolvedSymbols.count(RRKV.first) && "Redundant resolution?");
1220 ExternalSymbolMap.insert(KV: RRKV);
1221 ResolvedSymbols.insert(x: RRKV.first);
1222 }
1223 }
1224 }
1225
1226 applyExternalSymbolRelocations(ExternalSymbolMap);
1227
1228 return Error::success();
1229}
1230
1231void RuntimeDyldImpl::finalizeAsync(
1232 std::unique_ptr<RuntimeDyldImpl> This,
1233 unique_function<void(object::OwningBinary<object::ObjectFile>,
1234 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>, Error)>
1235 OnEmitted,
1236 object::OwningBinary<object::ObjectFile> O,
1237 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> Info) {
1238
1239 auto SharedThis = std::shared_ptr<RuntimeDyldImpl>(std::move(This));
1240 auto PostResolveContinuation =
1241 [SharedThis, OnEmitted = std::move(OnEmitted), O = std::move(O),
1242 Info = std::move(Info)](
1243 Expected<JITSymbolResolver::LookupResult> Result) mutable {
1244 if (!Result) {
1245 OnEmitted(std::move(O), std::move(Info), Result.takeError());
1246 return;
1247 }
1248
1249 /// Copy the result into a StringMap, where the keys are held by value.
1250 StringMap<JITEvaluatedSymbol> Resolved;
1251 for (auto &KV : *Result)
1252 Resolved[KV.first] = KV.second;
1253
1254 SharedThis->applyExternalSymbolRelocations(ExternalSymbolMap: Resolved);
1255 SharedThis->resolveLocalRelocations();
1256 SharedThis->registerEHFrames();
1257 std::string ErrMsg;
1258 if (SharedThis->MemMgr.finalizeMemory(ErrMsg: &ErrMsg))
1259 OnEmitted(std::move(O), std::move(Info),
1260 make_error<StringError>(Args: std::move(ErrMsg),
1261 Args: inconvertibleErrorCode()));
1262 else
1263 OnEmitted(std::move(O), std::move(Info), Error::success());
1264 };
1265
1266 JITSymbolResolver::LookupSet Symbols;
1267
1268 for (auto &RelocKV : SharedThis->ExternalSymbolRelocations) {
1269 StringRef Name = RelocKV.first();
1270 if (Name.empty()) // Skip absolute symbol relocations.
1271 continue;
1272 assert(!SharedThis->GlobalSymbolTable.count(Name) &&
1273 "Name already processed. RuntimeDyld instances can not be re-used "
1274 "when finalizing with finalizeAsync.");
1275 Symbols.insert(x: Name);
1276 }
1277
1278 if (!Symbols.empty()) {
1279 SharedThis->Resolver.lookup(Symbols, OnResolved: std::move(PostResolveContinuation));
1280 } else
1281 PostResolveContinuation(std::map<StringRef, JITEvaluatedSymbol>());
1282}
1283
1284//===----------------------------------------------------------------------===//
1285// RuntimeDyld class implementation
1286
1287uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
1288 const object::SectionRef &Sec) const {
1289
1290 auto I = ObjSecToIDMap.find(x: Sec);
1291 if (I != ObjSecToIDMap.end())
1292 return RTDyld.Sections[I->second].getLoadAddress();
1293
1294 return 0;
1295}
1296
1297RuntimeDyld::MemoryManager::TLSSection
1298RuntimeDyld::MemoryManager::allocateTLSSection(uintptr_t Size,
1299 unsigned Alignment,
1300 unsigned SectionID,
1301 StringRef SectionName) {
1302 report_fatal_error(reason: "allocation of TLS not implemented");
1303}
1304
1305void RuntimeDyld::MemoryManager::anchor() {}
1306void JITSymbolResolver::anchor() {}
1307void LegacyJITSymbolResolver::anchor() {}
1308
1309RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
1310 JITSymbolResolver &Resolver)
1311 : MemMgr(MemMgr), Resolver(Resolver) {
1312 // FIXME: There's a potential issue lurking here if a single instance of
1313 // RuntimeDyld is used to load multiple objects. The current implementation
1314 // associates a single memory manager with a RuntimeDyld instance. Even
1315 // though the public class spawns a new 'impl' instance for each load,
1316 // they share a single memory manager. This can become a problem when page
1317 // permissions are applied.
1318 Dyld = nullptr;
1319 ProcessAllSections = false;
1320}
1321
1322RuntimeDyld::~RuntimeDyld() = default;
1323
1324static std::unique_ptr<RuntimeDyldCOFF>
1325createRuntimeDyldCOFF(
1326 Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
1327 JITSymbolResolver &Resolver, bool ProcessAllSections,
1328 RuntimeDyld::NotifyStubEmittedFunction NotifyStubEmitted) {
1329 std::unique_ptr<RuntimeDyldCOFF> Dyld =
1330 RuntimeDyldCOFF::create(Arch, MemMgr&: MM, Resolver);
1331 Dyld->setProcessAllSections(ProcessAllSections);
1332 Dyld->setNotifyStubEmitted(std::move(NotifyStubEmitted));
1333 return Dyld;
1334}
1335
1336static std::unique_ptr<RuntimeDyldELF>
1337createRuntimeDyldELF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
1338 JITSymbolResolver &Resolver, bool ProcessAllSections,
1339 RuntimeDyld::NotifyStubEmittedFunction NotifyStubEmitted) {
1340 std::unique_ptr<RuntimeDyldELF> Dyld =
1341 RuntimeDyldELF::create(Arch, MemMgr&: MM, Resolver);
1342 Dyld->setProcessAllSections(ProcessAllSections);
1343 Dyld->setNotifyStubEmitted(std::move(NotifyStubEmitted));
1344 return Dyld;
1345}
1346
1347static std::unique_ptr<RuntimeDyldMachO>
1348createRuntimeDyldMachO(
1349 Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
1350 JITSymbolResolver &Resolver,
1351 bool ProcessAllSections,
1352 RuntimeDyld::NotifyStubEmittedFunction NotifyStubEmitted) {
1353 std::unique_ptr<RuntimeDyldMachO> Dyld =
1354 RuntimeDyldMachO::create(Arch, MemMgr&: MM, Resolver);
1355 Dyld->setProcessAllSections(ProcessAllSections);
1356 Dyld->setNotifyStubEmitted(std::move(NotifyStubEmitted));
1357 return Dyld;
1358}
1359
1360std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
1361RuntimeDyld::loadObject(const ObjectFile &Obj) {
1362 if (!Dyld) {
1363 if (Obj.isELF())
1364 Dyld =
1365 createRuntimeDyldELF(Arch: static_cast<Triple::ArchType>(Obj.getArch()),
1366 MM&: MemMgr, Resolver, ProcessAllSections,
1367 NotifyStubEmitted: std::move(NotifyStubEmitted));
1368 else if (Obj.isMachO())
1369 Dyld = createRuntimeDyldMachO(
1370 Arch: static_cast<Triple::ArchType>(Obj.getArch()), MM&: MemMgr, Resolver,
1371 ProcessAllSections, NotifyStubEmitted: std::move(NotifyStubEmitted));
1372 else if (Obj.isCOFF())
1373 Dyld = createRuntimeDyldCOFF(
1374 Arch: static_cast<Triple::ArchType>(Obj.getArch()), MM&: MemMgr, Resolver,
1375 ProcessAllSections, NotifyStubEmitted: std::move(NotifyStubEmitted));
1376 else
1377 report_fatal_error(reason: "Incompatible object format!");
1378 }
1379
1380 if (!Dyld->isCompatibleFile(Obj))
1381 report_fatal_error(reason: "Incompatible object format!");
1382
1383 auto LoadedObjInfo = Dyld->loadObject(Obj);
1384 MemMgr.notifyObjectLoaded(RTDyld&: *this, Obj);
1385 return LoadedObjInfo;
1386}
1387
1388void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
1389 if (!Dyld)
1390 return nullptr;
1391 return Dyld->getSymbolLocalAddress(Name);
1392}
1393
1394unsigned RuntimeDyld::getSymbolSectionID(StringRef Name) const {
1395 assert(Dyld && "No RuntimeDyld instance attached");
1396 return Dyld->getSymbolSectionID(Name);
1397}
1398
1399JITEvaluatedSymbol RuntimeDyld::getSymbol(StringRef Name) const {
1400 if (!Dyld)
1401 return nullptr;
1402 return Dyld->getSymbol(Name);
1403}
1404
1405std::map<StringRef, JITEvaluatedSymbol> RuntimeDyld::getSymbolTable() const {
1406 if (!Dyld)
1407 return std::map<StringRef, JITEvaluatedSymbol>();
1408 return Dyld->getSymbolTable();
1409}
1410
1411void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
1412
1413void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
1414 Dyld->reassignSectionAddress(SectionID, Addr);
1415}
1416
1417void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
1418 uint64_t TargetAddress) {
1419 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
1420}
1421
1422bool RuntimeDyld::hasError() { return Dyld->hasError(); }
1423
1424StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
1425
1426void RuntimeDyld::finalizeWithMemoryManagerLocking() {
1427 bool MemoryFinalizationLocked = MemMgr.FinalizationLocked;
1428 MemMgr.FinalizationLocked = true;
1429 resolveRelocations();
1430 registerEHFrames();
1431 if (!MemoryFinalizationLocked) {
1432 MemMgr.finalizeMemory();
1433 MemMgr.FinalizationLocked = false;
1434 }
1435}
1436
1437StringRef RuntimeDyld::getSectionContent(unsigned SectionID) const {
1438 assert(Dyld && "No Dyld instance attached");
1439 return Dyld->getSectionContent(SectionID);
1440}
1441
1442uint64_t RuntimeDyld::getSectionLoadAddress(unsigned SectionID) const {
1443 assert(Dyld && "No Dyld instance attached");
1444 return Dyld->getSectionLoadAddress(SectionID);
1445}
1446
1447void RuntimeDyld::registerEHFrames() {
1448 if (Dyld)
1449 Dyld->registerEHFrames();
1450}
1451
1452void RuntimeDyld::deregisterEHFrames() {
1453 if (Dyld)
1454 Dyld->deregisterEHFrames();
1455}
1456// FIXME: Kill this with fire once we have a new JIT linker: this is only here
1457// so that we can re-use RuntimeDyld's implementation without twisting the
1458// interface any further for ORC's purposes.
1459void jitLinkForORC(
1460 object::OwningBinary<object::ObjectFile> O,
1461 RuntimeDyld::MemoryManager &MemMgr, JITSymbolResolver &Resolver,
1462 bool ProcessAllSections,
1463 unique_function<Error(const object::ObjectFile &Obj,
1464 RuntimeDyld::LoadedObjectInfo &LoadedObj,
1465 std::map<StringRef, JITEvaluatedSymbol>)>
1466 OnLoaded,
1467 unique_function<void(object::OwningBinary<object::ObjectFile>,
1468 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>, Error)>
1469 OnEmitted) {
1470
1471 RuntimeDyld RTDyld(MemMgr, Resolver);
1472 RTDyld.setProcessAllSections(ProcessAllSections);
1473
1474 auto Info = RTDyld.loadObject(Obj: *O.getBinary());
1475
1476 if (RTDyld.hasError()) {
1477 OnEmitted(std::move(O), std::move(Info),
1478 make_error<StringError>(Args: RTDyld.getErrorString(),
1479 Args: inconvertibleErrorCode()));
1480 return;
1481 }
1482
1483 if (auto Err = OnLoaded(*O.getBinary(), *Info, RTDyld.getSymbolTable())) {
1484 OnEmitted(std::move(O), std::move(Info), std::move(Err));
1485 return;
1486 }
1487
1488 RuntimeDyldImpl::finalizeAsync(This: std::move(RTDyld.Dyld), OnEmitted: std::move(OnEmitted),
1489 O: std::move(O), Info: std::move(Info));
1490}
1491
1492} // end namespace llvm
1493