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(Fmt: "0x%016" PRIx64,
100 Vals: 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(Fmt: "0x%016" PRIx64, Vals: LoadAddr) << ":";
108
109 dbgs() << " " << format(Fmt: "%02x", Vals: *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 }
697
698 // Get section data size and alignment
699 uint64_t DataSize = Section.getSize();
700 Align Alignment = Section.getAlignment();
701
702 // Add stubbuf size alignment
703 Align StubAlignment = getStubAlignment();
704 Align EndAlignment = commonAlignment(A: Alignment, Offset: DataSize);
705 if (StubAlignment > EndAlignment)
706 StubBufSize += StubAlignment.value() - EndAlignment.value();
707 return StubBufSize;
708}
709
710uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
711 unsigned Size) const {
712 uint64_t Result = 0;
713 if (IsTargetLittleEndian) {
714 Src += Size - 1;
715 while (Size--)
716 Result = (Result << 8) | *Src--;
717 } else
718 while (Size--)
719 Result = (Result << 8) | *Src++;
720
721 return Result;
722}
723
724void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
725 unsigned Size) const {
726 if (IsTargetLittleEndian) {
727 while (Size--) {
728 *Dst++ = Value & 0xFF;
729 Value >>= 8;
730 }
731 } else {
732 Dst += Size - 1;
733 while (Size--) {
734 *Dst-- = Value & 0xFF;
735 Value >>= 8;
736 }
737 }
738}
739
740Expected<JITSymbolFlags>
741RuntimeDyldImpl::getJITSymbolFlags(const SymbolRef &SR) {
742 return JITSymbolFlags::fromObjectSymbol(Symbol: SR);
743}
744
745Error RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
746 CommonSymbolList &SymbolsToAllocate,
747 uint64_t CommonSize,
748 uint32_t CommonAlign) {
749 if (SymbolsToAllocate.empty())
750 return Error::success();
751
752 // Allocate memory for the section
753 unsigned SectionID = Sections.size();
754 uint8_t *Addr = MemMgr.allocateDataSection(Size: CommonSize, Alignment: CommonAlign, SectionID,
755 SectionName: "<common symbols>", IsReadOnly: false);
756 if (!Addr)
757 report_fatal_error(reason: "Unable to allocate memory for common symbols!");
758 uint64_t Offset = 0;
759 Sections.push_back(
760 x: SectionEntry("<common symbols>", Addr, CommonSize, CommonSize, 0));
761 memset(s: Addr, c: 0, n: CommonSize);
762
763 LLVM_DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID
764 << " new addr: " << format("%p", Addr)
765 << " DataSize: " << CommonSize << "\n");
766
767 // Assign the address of each symbol
768 for (auto &Sym : SymbolsToAllocate) {
769 uint32_t Alignment = Sym.getAlignment();
770 uint64_t Size = Sym.getCommonSize();
771 StringRef Name;
772 if (auto NameOrErr = Sym.getName())
773 Name = *NameOrErr;
774 else
775 return NameOrErr.takeError();
776 if (Alignment) {
777 // This symbol has an alignment requirement.
778 uint64_t AlignOffset =
779 offsetToAlignment(Value: (uint64_t)Addr, Alignment: Align(Alignment));
780 Addr += AlignOffset;
781 Offset += AlignOffset;
782 }
783 auto JITSymFlags = getJITSymbolFlags(SR: Sym);
784
785 if (!JITSymFlags)
786 return JITSymFlags.takeError();
787
788 LLVM_DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
789 << format("%p", Addr) << "\n");
790 if (!Name.empty()) // Skip absolute symbol relocations.
791 GlobalSymbolTable[Name] =
792 SymbolTableEntry(SectionID, Offset, std::move(*JITSymFlags));
793 Offset += Size;
794 Addr += Size;
795 }
796
797 return Error::success();
798}
799
800Expected<unsigned>
801RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
802 const SectionRef &Section,
803 bool IsCode) {
804 StringRef data;
805 Align Alignment = Section.getAlignment();
806
807 unsigned PaddingSize = 0;
808 unsigned StubBufSize = 0;
809 bool IsRequired = isRequiredForExecution(Section);
810 bool IsVirtual = Section.isVirtual();
811 bool IsZeroInit = isZeroInit(Section);
812 bool IsReadOnly = isReadOnlyData(Section);
813 bool IsTLS = isTLS(Section);
814 uint64_t DataSize = Section.getSize();
815
816 Expected<StringRef> NameOrErr = Section.getName();
817 if (!NameOrErr)
818 return NameOrErr.takeError();
819 StringRef Name = *NameOrErr;
820
821 StubBufSize = computeSectionStubBufSize(Obj, Section);
822
823 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
824 // with zeroes added at the end. For MachO objects, this section has a
825 // slightly different name, so this won't have any effect for MachO objects.
826 if (Name == ".eh_frame")
827 PaddingSize = 4;
828
829 uintptr_t Allocate;
830 unsigned SectionID = Sections.size();
831 uint8_t *Addr;
832 uint64_t LoadAddress = 0;
833 const char *pData = nullptr;
834
835 // If this section contains any bits (i.e. isn't a virtual or bss section),
836 // grab a reference to them.
837 if (!IsVirtual && !IsZeroInit) {
838 // In either case, set the location of the unrelocated section in memory,
839 // since we still process relocations for it even if we're not applying them.
840 if (Expected<StringRef> E = Section.getContents())
841 data = *E;
842 else
843 return E.takeError();
844 pData = data.data();
845 }
846
847 // If there are any stubs then the section alignment needs to be at least as
848 // high as stub alignment or padding calculations may by incorrect when the
849 // section is remapped.
850 if (StubBufSize != 0) {
851 Alignment = std::max(a: Alignment, b: getStubAlignment());
852 PaddingSize += getStubAlignment().value() - 1;
853 }
854
855 // Some sections, such as debug info, don't need to be loaded for execution.
856 // Process those only if explicitly requested.
857 if (IsRequired || ProcessAllSections) {
858 Allocate = DataSize + PaddingSize + StubBufSize;
859 if (!Allocate)
860 Allocate = 1;
861 if (IsTLS) {
862 auto TLSSection = MemMgr.allocateTLSSection(Size: Allocate, Alignment: Alignment.value(),
863 SectionID, SectionName: Name);
864 Addr = TLSSection.InitializationImage;
865 LoadAddress = TLSSection.Offset;
866 } else if (IsCode) {
867 Addr = MemMgr.allocateCodeSection(Size: Allocate, Alignment: Alignment.value(), SectionID,
868 SectionName: Name);
869 } else {
870 Addr = MemMgr.allocateDataSection(Size: Allocate, Alignment: Alignment.value(), SectionID,
871 SectionName: Name, IsReadOnly);
872 }
873 if (!Addr)
874 report_fatal_error(reason: "Unable to allocate section memory!");
875
876 // Zero-initialize or copy the data from the image
877 if (IsZeroInit || IsVirtual)
878 memset(s: Addr, c: 0, n: DataSize);
879 else
880 memcpy(dest: Addr, src: pData, n: DataSize);
881
882 // Fill in any extra bytes we allocated for padding
883 if (PaddingSize != 0) {
884 memset(s: Addr + DataSize, c: 0, n: PaddingSize);
885 // Update the DataSize variable to include padding.
886 DataSize += PaddingSize;
887
888 // Align DataSize to stub alignment if we have any stubs (PaddingSize will
889 // have been increased above to account for this).
890 if (StubBufSize > 0)
891 DataSize &= -(uint64_t)getStubAlignment().value();
892 }
893
894 LLVM_DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: "
895 << Name << " obj addr: " << format("%p", pData)
896 << " new addr: " << format("%p", Addr) << " DataSize: "
897 << DataSize << " StubBufSize: " << StubBufSize
898 << " Allocate: " << Allocate << "\n");
899 } else {
900 // Even if we didn't load the section, we need to record an entry for it
901 // to handle later processing (and by 'handle' I mean don't do anything
902 // with these sections).
903 Allocate = 0;
904 Addr = nullptr;
905 LLVM_DEBUG(
906 dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
907 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
908 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
909 << " Allocate: " << Allocate << "\n");
910 }
911
912 Sections.push_back(
913 x: SectionEntry(Name, Addr, DataSize, Allocate, (uintptr_t)pData));
914
915 // The load address of a TLS section is not equal to the address of its
916 // initialization image
917 if (IsTLS)
918 Sections.back().setLoadAddress(LoadAddress);
919 // Debug info sections are linked as if their load address was zero
920 if (!IsRequired)
921 Sections.back().setLoadAddress(0);
922
923 return SectionID;
924}
925
926Expected<unsigned>
927RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
928 const SectionRef &Section,
929 bool IsCode,
930 ObjSectionToIDMap &LocalSections) {
931
932 unsigned SectionID = 0;
933 ObjSectionToIDMap::iterator i = LocalSections.find(x: Section);
934 if (i != LocalSections.end())
935 SectionID = i->second;
936 else {
937 if (auto SectionIDOrErr = emitSection(Obj, Section, IsCode))
938 SectionID = *SectionIDOrErr;
939 else
940 return SectionIDOrErr.takeError();
941 LocalSections[Section] = SectionID;
942 }
943 return SectionID;
944}
945
946void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
947 unsigned SectionID) {
948 Relocations[SectionID].push_back(Elt: RE);
949}
950
951void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
952 StringRef SymbolName) {
953 // Relocation by symbol. If the symbol is found in the global symbol table,
954 // create an appropriate section relocation. Otherwise, add it to
955 // ExternalSymbolRelocations.
956 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Key: SymbolName);
957 if (Loc == GlobalSymbolTable.end()) {
958 ExternalSymbolRelocations[SymbolName].push_back(Elt: RE);
959 } else {
960 assert(!SymbolName.empty() &&
961 "Empty symbol should not be in GlobalSymbolTable");
962 // Copy the RE since we want to modify its addend.
963 RelocationEntry RECopy = RE;
964 const auto &SymInfo = Loc->second;
965 RECopy.Addend += SymInfo.getOffset();
966 Relocations[SymInfo.getSectionID()].push_back(Elt: RECopy);
967 }
968}
969
970uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
971 unsigned AbiVariant) {
972 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be ||
973 Arch == Triple::aarch64_32) {
974 // This stub has to be able to access the full address space,
975 // since symbol lookup won't necessarily find a handy, in-range,
976 // PLT stub for functions which could be anywhere.
977 // Stub can use ip0 (== x16) to calculate address
978 writeBytesUnaligned(Value: 0xd2e00010, Dst: Addr, Size: 4); // movz ip0, #:abs_g3:<addr>
979 writeBytesUnaligned(Value: 0xf2c00010, Dst: Addr+4, Size: 4); // movk ip0, #:abs_g2_nc:<addr>
980 writeBytesUnaligned(Value: 0xf2a00010, Dst: Addr+8, Size: 4); // movk ip0, #:abs_g1_nc:<addr>
981 writeBytesUnaligned(Value: 0xf2800010, Dst: Addr+12, Size: 4); // movk ip0, #:abs_g0_nc:<addr>
982 writeBytesUnaligned(Value: 0xd61f0200, Dst: Addr+16, Size: 4); // br ip0
983
984 return Addr;
985 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
986 // TODO: There is only ARM far stub now. We should add the Thumb stub,
987 // and stubs for branches Thumb - ARM and ARM - Thumb.
988 writeBytesUnaligned(Value: 0xe51ff004, Dst: Addr, Size: 4); // ldr pc, [pc, #-4]
989 return Addr + 4;
990 } else if (IsMipsO32ABI || IsMipsN32ABI) {
991 // 0: 3c190000 lui t9,%hi(addr).
992 // 4: 27390000 addiu t9,t9,%lo(addr).
993 // 8: 03200008 jr t9.
994 // c: 00000000 nop.
995 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
996 const unsigned NopInstr = 0x0;
997 unsigned JrT9Instr = 0x03200008;
998 if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_32R6 ||
999 (AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
1000 JrT9Instr = 0x03200009;
1001
1002 writeBytesUnaligned(Value: LuiT9Instr, Dst: Addr, Size: 4);
1003 writeBytesUnaligned(Value: AdduiT9Instr, Dst: Addr + 4, Size: 4);
1004 writeBytesUnaligned(Value: JrT9Instr, Dst: Addr + 8, Size: 4);
1005 writeBytesUnaligned(Value: NopInstr, Dst: Addr + 12, Size: 4);
1006 return Addr;
1007 } else if (IsMipsN64ABI) {
1008 // 0: 3c190000 lui t9,%highest(addr).
1009 // 4: 67390000 daddiu t9,t9,%higher(addr).
1010 // 8: 0019CC38 dsll t9,t9,16.
1011 // c: 67390000 daddiu t9,t9,%hi(addr).
1012 // 10: 0019CC38 dsll t9,t9,16.
1013 // 14: 67390000 daddiu t9,t9,%lo(addr).
1014 // 18: 03200008 jr t9.
1015 // 1c: 00000000 nop.
1016 const unsigned LuiT9Instr = 0x3c190000, DaddiuT9Instr = 0x67390000,
1017 DsllT9Instr = 0x19CC38;
1018 const unsigned NopInstr = 0x0;
1019 unsigned JrT9Instr = 0x03200008;
1020 if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
1021 JrT9Instr = 0x03200009;
1022
1023 writeBytesUnaligned(Value: LuiT9Instr, Dst: Addr, Size: 4);
1024 writeBytesUnaligned(Value: DaddiuT9Instr, Dst: Addr + 4, Size: 4);
1025 writeBytesUnaligned(Value: DsllT9Instr, Dst: Addr + 8, Size: 4);
1026 writeBytesUnaligned(Value: DaddiuT9Instr, Dst: Addr + 12, Size: 4);
1027 writeBytesUnaligned(Value: DsllT9Instr, Dst: Addr + 16, Size: 4);
1028 writeBytesUnaligned(Value: DaddiuT9Instr, Dst: Addr + 20, Size: 4);
1029 writeBytesUnaligned(Value: JrT9Instr, Dst: Addr + 24, Size: 4);
1030 writeBytesUnaligned(Value: NopInstr, Dst: Addr + 28, Size: 4);
1031 return Addr;
1032 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
1033 // Depending on which version of the ELF ABI is in use, we need to
1034 // generate one of two variants of the stub. They both start with
1035 // the same sequence to load the target address into r12.
1036 writeInt32BE(Addr, Value: 0x3D800000); // lis r12, highest(addr)
1037 writeInt32BE(Addr: Addr+4, Value: 0x618C0000); // ori r12, higher(addr)
1038 writeInt32BE(Addr: Addr+8, Value: 0x798C07C6); // sldi r12, r12, 32
1039 writeInt32BE(Addr: Addr+12, Value: 0x658C0000); // oris r12, r12, h(addr)
1040 writeInt32BE(Addr: Addr+16, Value: 0x618C0000); // ori r12, r12, l(addr)
1041 if (AbiVariant == 2) {
1042 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
1043 // The address is already in r12 as required by the ABI. Branch to it.
1044 writeInt32BE(Addr: Addr+20, Value: 0xF8410018); // std r2, 24(r1)
1045 writeInt32BE(Addr: Addr+24, Value: 0x7D8903A6); // mtctr r12
1046 writeInt32BE(Addr: Addr+28, Value: 0x4E800420); // bctr
1047 } else {
1048 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
1049 // Load the function address on r11 and sets it to control register. Also
1050 // loads the function TOC in r2 and environment pointer to r11.
1051 writeInt32BE(Addr: Addr+20, Value: 0xF8410028); // std r2, 40(r1)
1052 writeInt32BE(Addr: Addr+24, Value: 0xE96C0000); // ld r11, 0(r12)
1053 writeInt32BE(Addr: Addr+28, Value: 0xE84C0008); // ld r2, 0(r12)
1054 writeInt32BE(Addr: Addr+32, Value: 0x7D6903A6); // mtctr r11
1055 writeInt32BE(Addr: Addr+36, Value: 0xE96C0010); // ld r11, 16(r2)
1056 writeInt32BE(Addr: Addr+40, Value: 0x4E800420); // bctr
1057 }
1058 return Addr;
1059 } else if (Arch == Triple::systemz) {
1060 writeInt16BE(Addr, Value: 0xC418); // lgrl %r1,.+8
1061 writeInt16BE(Addr: Addr+2, Value: 0x0000);
1062 writeInt16BE(Addr: Addr+4, Value: 0x0004);
1063 writeInt16BE(Addr: Addr+6, Value: 0x07F1); // brc 15,%r1
1064 // 8-byte address stored at Addr + 8
1065 return Addr;
1066 } else if (Arch == Triple::x86_64) {
1067 *Addr = 0xFF; // jmp
1068 *(Addr+1) = 0x25; // rip
1069 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
1070 } else if (Arch == Triple::x86) {
1071 *Addr = 0xE9; // 32-bit pc-relative jump.
1072 }
1073 return Addr;
1074}
1075
1076// Assign an address to a symbol name and resolve all the relocations
1077// associated with it.
1078void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
1079 uint64_t Addr) {
1080 // The address to use for relocation resolution is not
1081 // the address of the local section buffer. We must be doing
1082 // a remote execution environment of some sort. Relocations can't
1083 // be applied until all the sections have been moved. The client must
1084 // trigger this with a call to MCJIT::finalize() or
1085 // RuntimeDyld::resolveRelocations().
1086 //
1087 // Addr is a uint64_t because we can't assume the pointer width
1088 // of the target is the same as that of the host. Just use a generic
1089 // "big enough" type.
1090 LLVM_DEBUG(
1091 dbgs() << "Reassigning address for section " << SectionID << " ("
1092 << Sections[SectionID].getName() << "): "
1093 << format("0x%016" PRIx64, Sections[SectionID].getLoadAddress())
1094 << " -> " << format("0x%016" PRIx64, Addr) << "\n");
1095 Sections[SectionID].setLoadAddress(Addr);
1096}
1097
1098void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
1099 uint64_t Value) {
1100 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
1101 const RelocationEntry &RE = Relocs[i];
1102 // Ignore relocations for sections that were not loaded
1103 if (RE.SectionID != AbsoluteSymbolSection &&
1104 Sections[RE.SectionID].getAddress() == nullptr)
1105 continue;
1106 resolveRelocation(RE, Value);
1107 }
1108}
1109
1110void RuntimeDyldImpl::applyExternalSymbolRelocations(
1111 const StringMap<JITEvaluatedSymbol> ExternalSymbolMap) {
1112 for (auto &RelocKV : ExternalSymbolRelocations) {
1113 StringRef Name = RelocKV.first();
1114 RelocationList &Relocs = RelocKV.second;
1115 if (Name.size() == 0) {
1116 // This is an absolute symbol, use an address of zero.
1117 LLVM_DEBUG(dbgs() << "Resolving absolute relocations."
1118 << "\n");
1119 resolveRelocationList(Relocs, Value: 0);
1120 } else {
1121 uint64_t Addr = 0;
1122 JITSymbolFlags Flags;
1123 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Key: Name);
1124 if (Loc == GlobalSymbolTable.end()) {
1125 auto RRI = ExternalSymbolMap.find(Key: Name);
1126 assert(RRI != ExternalSymbolMap.end() && "No result for symbol");
1127 Addr = RRI->second.getAddress();
1128 Flags = RRI->second.getFlags();
1129 } else {
1130 // We found the symbol in our global table. It was probably in a
1131 // Module that we loaded previously.
1132 const auto &SymInfo = Loc->second;
1133 Addr = getSectionLoadAddress(SectionID: SymInfo.getSectionID()) +
1134 SymInfo.getOffset();
1135 Flags = SymInfo.getFlags();
1136 }
1137
1138 // FIXME: Implement error handling that doesn't kill the host program!
1139 if (!Addr && !Resolver.allowsZeroSymbols())
1140 report_fatal_error(reason: Twine("Program used external function '") + Name +
1141 "' which could not be resolved!");
1142
1143 // If Resolver returned UINT64_MAX, the client wants to handle this symbol
1144 // manually and we shouldn't resolve its relocations.
1145 if (Addr != UINT64_MAX) {
1146
1147 // Tweak the address based on the symbol flags if necessary.
1148 // For example, this is used by RuntimeDyldMachOARM to toggle the low bit
1149 // if the target symbol is Thumb.
1150 Addr = modifyAddressBasedOnFlags(Addr, Flags);
1151
1152 LLVM_DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
1153 << format("0x%lx", Addr) << "\n");
1154 resolveRelocationList(Relocs, Value: Addr);
1155 }
1156 }
1157 }
1158 ExternalSymbolRelocations.clear();
1159}
1160
1161Error RuntimeDyldImpl::resolveExternalSymbols() {
1162 StringMap<JITEvaluatedSymbol> ExternalSymbolMap;
1163
1164 // Resolution can trigger emission of more symbols, so iterate until
1165 // we've resolved *everything*.
1166 {
1167 JITSymbolResolver::LookupSet ResolvedSymbols;
1168
1169 while (true) {
1170 JITSymbolResolver::LookupSet NewSymbols;
1171
1172 for (auto &RelocKV : ExternalSymbolRelocations) {
1173 StringRef Name = RelocKV.first();
1174 if (!Name.empty() && !GlobalSymbolTable.count(Key: Name) &&
1175 !ResolvedSymbols.count(x: Name))
1176 NewSymbols.insert(x: Name);
1177 }
1178
1179 if (NewSymbols.empty())
1180 break;
1181
1182#ifdef _MSC_VER
1183 using ExpectedLookupResult =
1184 MSVCPExpected<JITSymbolResolver::LookupResult>;
1185#else
1186 using ExpectedLookupResult = Expected<JITSymbolResolver::LookupResult>;
1187#endif
1188
1189 auto NewSymbolsP = std::make_shared<std::promise<ExpectedLookupResult>>();
1190 auto NewSymbolsF = NewSymbolsP->get_future();
1191 Resolver.lookup(Symbols: NewSymbols,
1192 OnResolved: [=](Expected<JITSymbolResolver::LookupResult> Result) {
1193 NewSymbolsP->set_value(std::move(Result));
1194 });
1195
1196 auto NewResolverResults = NewSymbolsF.get();
1197
1198 if (!NewResolverResults)
1199 return NewResolverResults.takeError();
1200
1201 assert(NewResolverResults->size() == NewSymbols.size() &&
1202 "Should have errored on unresolved symbols");
1203
1204 for (auto &RRKV : *NewResolverResults) {
1205 assert(!ResolvedSymbols.count(RRKV.first) && "Redundant resolution?");
1206 ExternalSymbolMap.insert(KV: RRKV);
1207 ResolvedSymbols.insert(x: RRKV.first);
1208 }
1209 }
1210 }
1211
1212 applyExternalSymbolRelocations(ExternalSymbolMap);
1213
1214 return Error::success();
1215}
1216
1217void RuntimeDyldImpl::finalizeAsync(
1218 std::unique_ptr<RuntimeDyldImpl> This,
1219 unique_function<void(object::OwningBinary<object::ObjectFile>,
1220 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>, Error)>
1221 OnEmitted,
1222 object::OwningBinary<object::ObjectFile> O,
1223 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> Info) {
1224
1225 auto SharedThis = std::shared_ptr<RuntimeDyldImpl>(std::move(This));
1226 auto PostResolveContinuation =
1227 [SharedThis, OnEmitted = std::move(OnEmitted), O = std::move(O),
1228 Info = std::move(Info)](
1229 Expected<JITSymbolResolver::LookupResult> Result) mutable {
1230 if (!Result) {
1231 OnEmitted(std::move(O), std::move(Info), Result.takeError());
1232 return;
1233 }
1234
1235 /// Copy the result into a StringMap, where the keys are held by value.
1236 StringMap<JITEvaluatedSymbol> Resolved;
1237 for (auto &KV : *Result)
1238 Resolved[KV.first] = KV.second;
1239
1240 SharedThis->applyExternalSymbolRelocations(ExternalSymbolMap: Resolved);
1241 SharedThis->resolveLocalRelocations();
1242 SharedThis->registerEHFrames();
1243 std::string ErrMsg;
1244 if (SharedThis->MemMgr.finalizeMemory(ErrMsg: &ErrMsg))
1245 OnEmitted(std::move(O), std::move(Info),
1246 make_error<StringError>(Args: std::move(ErrMsg),
1247 Args: inconvertibleErrorCode()));
1248 else
1249 OnEmitted(std::move(O), std::move(Info), Error::success());
1250 };
1251
1252 JITSymbolResolver::LookupSet Symbols;
1253
1254 for (auto &RelocKV : SharedThis->ExternalSymbolRelocations) {
1255 StringRef Name = RelocKV.first();
1256 if (Name.empty()) // Skip absolute symbol relocations.
1257 continue;
1258 assert(!SharedThis->GlobalSymbolTable.count(Name) &&
1259 "Name already processed. RuntimeDyld instances can not be re-used "
1260 "when finalizing with finalizeAsync.");
1261 Symbols.insert(x: Name);
1262 }
1263
1264 if (!Symbols.empty()) {
1265 SharedThis->Resolver.lookup(Symbols, OnResolved: std::move(PostResolveContinuation));
1266 } else
1267 PostResolveContinuation(std::map<StringRef, JITEvaluatedSymbol>());
1268}
1269
1270//===----------------------------------------------------------------------===//
1271// RuntimeDyld class implementation
1272
1273uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
1274 const object::SectionRef &Sec) const {
1275
1276 auto I = ObjSecToIDMap.find(x: Sec);
1277 if (I != ObjSecToIDMap.end())
1278 return RTDyld.Sections[I->second].getLoadAddress();
1279
1280 return 0;
1281}
1282
1283RuntimeDyld::MemoryManager::TLSSection
1284RuntimeDyld::MemoryManager::allocateTLSSection(uintptr_t Size,
1285 unsigned Alignment,
1286 unsigned SectionID,
1287 StringRef SectionName) {
1288 report_fatal_error(reason: "allocation of TLS not implemented");
1289}
1290
1291void RuntimeDyld::MemoryManager::anchor() {}
1292void JITSymbolResolver::anchor() {}
1293void LegacyJITSymbolResolver::anchor() {}
1294
1295RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
1296 JITSymbolResolver &Resolver)
1297 : MemMgr(MemMgr), Resolver(Resolver) {
1298 // FIXME: There's a potential issue lurking here if a single instance of
1299 // RuntimeDyld is used to load multiple objects. The current implementation
1300 // associates a single memory manager with a RuntimeDyld instance. Even
1301 // though the public class spawns a new 'impl' instance for each load,
1302 // they share a single memory manager. This can become a problem when page
1303 // permissions are applied.
1304 Dyld = nullptr;
1305 ProcessAllSections = false;
1306}
1307
1308RuntimeDyld::~RuntimeDyld() = default;
1309
1310static std::unique_ptr<RuntimeDyldCOFF>
1311createRuntimeDyldCOFF(
1312 Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
1313 JITSymbolResolver &Resolver, bool ProcessAllSections,
1314 RuntimeDyld::NotifyStubEmittedFunction NotifyStubEmitted) {
1315 std::unique_ptr<RuntimeDyldCOFF> Dyld =
1316 RuntimeDyldCOFF::create(Arch, MemMgr&: MM, Resolver);
1317 Dyld->setProcessAllSections(ProcessAllSections);
1318 Dyld->setNotifyStubEmitted(std::move(NotifyStubEmitted));
1319 return Dyld;
1320}
1321
1322static std::unique_ptr<RuntimeDyldELF>
1323createRuntimeDyldELF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
1324 JITSymbolResolver &Resolver, bool ProcessAllSections,
1325 RuntimeDyld::NotifyStubEmittedFunction NotifyStubEmitted) {
1326 std::unique_ptr<RuntimeDyldELF> Dyld =
1327 RuntimeDyldELF::create(Arch, MemMgr&: MM, Resolver);
1328 Dyld->setProcessAllSections(ProcessAllSections);
1329 Dyld->setNotifyStubEmitted(std::move(NotifyStubEmitted));
1330 return Dyld;
1331}
1332
1333static std::unique_ptr<RuntimeDyldMachO>
1334createRuntimeDyldMachO(
1335 Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
1336 JITSymbolResolver &Resolver,
1337 bool ProcessAllSections,
1338 RuntimeDyld::NotifyStubEmittedFunction NotifyStubEmitted) {
1339 std::unique_ptr<RuntimeDyldMachO> Dyld =
1340 RuntimeDyldMachO::create(Arch, MemMgr&: MM, Resolver);
1341 Dyld->setProcessAllSections(ProcessAllSections);
1342 Dyld->setNotifyStubEmitted(std::move(NotifyStubEmitted));
1343 return Dyld;
1344}
1345
1346std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
1347RuntimeDyld::loadObject(const ObjectFile &Obj) {
1348 if (!Dyld) {
1349 if (Obj.isELF())
1350 Dyld =
1351 createRuntimeDyldELF(Arch: static_cast<Triple::ArchType>(Obj.getArch()),
1352 MM&: MemMgr, Resolver, ProcessAllSections,
1353 NotifyStubEmitted: std::move(NotifyStubEmitted));
1354 else if (Obj.isMachO())
1355 Dyld = createRuntimeDyldMachO(
1356 Arch: static_cast<Triple::ArchType>(Obj.getArch()), MM&: MemMgr, Resolver,
1357 ProcessAllSections, NotifyStubEmitted: std::move(NotifyStubEmitted));
1358 else if (Obj.isCOFF())
1359 Dyld = createRuntimeDyldCOFF(
1360 Arch: static_cast<Triple::ArchType>(Obj.getArch()), MM&: MemMgr, Resolver,
1361 ProcessAllSections, NotifyStubEmitted: std::move(NotifyStubEmitted));
1362 else
1363 report_fatal_error(reason: "Incompatible object format!");
1364 }
1365
1366 if (!Dyld->isCompatibleFile(Obj))
1367 report_fatal_error(reason: "Incompatible object format!");
1368
1369 auto LoadedObjInfo = Dyld->loadObject(Obj);
1370 MemMgr.notifyObjectLoaded(RTDyld&: *this, Obj);
1371 return LoadedObjInfo;
1372}
1373
1374void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
1375 if (!Dyld)
1376 return nullptr;
1377 return Dyld->getSymbolLocalAddress(Name);
1378}
1379
1380unsigned RuntimeDyld::getSymbolSectionID(StringRef Name) const {
1381 assert(Dyld && "No RuntimeDyld instance attached");
1382 return Dyld->getSymbolSectionID(Name);
1383}
1384
1385JITEvaluatedSymbol RuntimeDyld::getSymbol(StringRef Name) const {
1386 if (!Dyld)
1387 return nullptr;
1388 return Dyld->getSymbol(Name);
1389}
1390
1391std::map<StringRef, JITEvaluatedSymbol> RuntimeDyld::getSymbolTable() const {
1392 if (!Dyld)
1393 return std::map<StringRef, JITEvaluatedSymbol>();
1394 return Dyld->getSymbolTable();
1395}
1396
1397void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
1398
1399void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
1400 Dyld->reassignSectionAddress(SectionID, Addr);
1401}
1402
1403void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
1404 uint64_t TargetAddress) {
1405 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
1406}
1407
1408bool RuntimeDyld::hasError() { return Dyld->hasError(); }
1409
1410StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
1411
1412void RuntimeDyld::finalizeWithMemoryManagerLocking() {
1413 bool MemoryFinalizationLocked = MemMgr.FinalizationLocked;
1414 MemMgr.FinalizationLocked = true;
1415 resolveRelocations();
1416 registerEHFrames();
1417 if (!MemoryFinalizationLocked) {
1418 MemMgr.finalizeMemory();
1419 MemMgr.FinalizationLocked = false;
1420 }
1421}
1422
1423StringRef RuntimeDyld::getSectionContent(unsigned SectionID) const {
1424 assert(Dyld && "No Dyld instance attached");
1425 return Dyld->getSectionContent(SectionID);
1426}
1427
1428uint64_t RuntimeDyld::getSectionLoadAddress(unsigned SectionID) const {
1429 assert(Dyld && "No Dyld instance attached");
1430 return Dyld->getSectionLoadAddress(SectionID);
1431}
1432
1433void RuntimeDyld::registerEHFrames() {
1434 if (Dyld)
1435 Dyld->registerEHFrames();
1436}
1437
1438void RuntimeDyld::deregisterEHFrames() {
1439 if (Dyld)
1440 Dyld->deregisterEHFrames();
1441}
1442// FIXME: Kill this with fire once we have a new JIT linker: this is only here
1443// so that we can re-use RuntimeDyld's implementation without twisting the
1444// interface any further for ORC's purposes.
1445void jitLinkForORC(
1446 object::OwningBinary<object::ObjectFile> O,
1447 RuntimeDyld::MemoryManager &MemMgr, JITSymbolResolver &Resolver,
1448 bool ProcessAllSections,
1449 unique_function<Error(const object::ObjectFile &Obj,
1450 RuntimeDyld::LoadedObjectInfo &LoadedObj,
1451 std::map<StringRef, JITEvaluatedSymbol>)>
1452 OnLoaded,
1453 unique_function<void(object::OwningBinary<object::ObjectFile>,
1454 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>, Error)>
1455 OnEmitted) {
1456
1457 RuntimeDyld RTDyld(MemMgr, Resolver);
1458 RTDyld.setProcessAllSections(ProcessAllSections);
1459
1460 auto Info = RTDyld.loadObject(Obj: *O.getBinary());
1461
1462 if (RTDyld.hasError()) {
1463 OnEmitted(std::move(O), std::move(Info),
1464 make_error<StringError>(Args: RTDyld.getErrorString(),
1465 Args: inconvertibleErrorCode()));
1466 return;
1467 }
1468
1469 if (auto Err = OnLoaded(*O.getBinary(), *Info, RTDyld.getSymbolTable()))
1470 OnEmitted(std::move(O), std::move(Info), std::move(Err));
1471
1472 RuntimeDyldImpl::finalizeAsync(This: std::move(RTDyld.Dyld), OnEmitted: std::move(OnEmitted),
1473 O: std::move(O), Info: std::move(Info));
1474}
1475
1476} // end namespace llvm
1477

source code of llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp