Bug Summary

File:llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
Warning:line 1446, column 34
Moved-from object 'O' is moved

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name RuntimeDyld.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/lib/ExecutionEngine/RuntimeDyld -resource-dir /usr/lib/llvm-14/lib/clang/14.0.0 -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/lib/ExecutionEngine/RuntimeDyld -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/lib/ExecutionEngine/RuntimeDyld -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/include -I /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/include -D NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/build-llvm/lib/ExecutionEngine/RuntimeDyld -fdebug-prefix-map=/build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2021-09-04-040900-46481-1 -x c++ /build/llvm-toolchain-snapshot-14~++20210903100615+fd66b44ec19e/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
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/ManagedStatic.h"
23#include "llvm/Support/MathExtras.h"
24#include <mutex>
25
26#include <future>
27
28using namespace llvm;
29using namespace llvm::object;
30
31#define DEBUG_TYPE"dyld" "dyld"
32
33namespace {
34
35enum RuntimeDyldErrorCode {
36 GenericRTDyldError = 1
37};
38
39// FIXME: This class is only here to support the transition to llvm::Error. It
40// will be removed once this transition is complete. Clients should prefer to
41// deal with the Error value directly, rather than converting to error_code.
42class RuntimeDyldErrorCategory : public std::error_category {
43public:
44 const char *name() const noexcept override { return "runtimedyld"; }
45
46 std::string message(int Condition) const override {
47 switch (static_cast<RuntimeDyldErrorCode>(Condition)) {
48 case GenericRTDyldError: return "Generic RuntimeDyld error";
49 }
50 llvm_unreachable("Unrecognized RuntimeDyldErrorCode")__builtin_unreachable();
51 }
52};
53
54static ManagedStatic<RuntimeDyldErrorCategory> RTDyldErrorCategory;
55
56}
57
58char RuntimeDyldError::ID = 0;
59
60void RuntimeDyldError::log(raw_ostream &OS) const {
61 OS << ErrMsg << "\n";
62}
63
64std::error_code RuntimeDyldError::convertToErrorCode() const {
65 return std::error_code(GenericRTDyldError, *RTDyldErrorCategory);
66}
67
68// Empty out-of-line virtual destructor as the key function.
69RuntimeDyldImpl::~RuntimeDyldImpl() {}
70
71// Pin LoadedObjectInfo's vtables to this file.
72void RuntimeDyld::LoadedObjectInfo::anchor() {}
73
74namespace llvm {
75
76void RuntimeDyldImpl::registerEHFrames() {}
77
78void RuntimeDyldImpl::deregisterEHFrames() {
79 MemMgr.deregisterEHFrames();
80}
81
82#ifndef NDEBUG1
83static void dumpSectionMemory(const SectionEntry &S, StringRef State) {
84 dbgs() << "----- Contents of section " << S.getName() << " " << State
85 << " -----";
86
87 if (S.getAddress() == nullptr) {
88 dbgs() << "\n <section not emitted>\n";
89 return;
90 }
91
92 const unsigned ColsPerRow = 16;
93
94 uint8_t *DataAddr = S.getAddress();
95 uint64_t LoadAddr = S.getLoadAddress();
96
97 unsigned StartPadding = LoadAddr & (ColsPerRow - 1);
98 unsigned BytesRemaining = S.getSize();
99
100 if (StartPadding) {
101 dbgs() << "\n" << format("0x%016" PRIx64"l" "x",
102 LoadAddr & ~(uint64_t)(ColsPerRow - 1)) << ":";
103 while (StartPadding--)
104 dbgs() << " ";
105 }
106
107 while (BytesRemaining > 0) {
108 if ((LoadAddr & (ColsPerRow - 1)) == 0)
109 dbgs() << "\n" << format("0x%016" PRIx64"l" "x", LoadAddr) << ":";
110
111 dbgs() << " " << format("%02x", *DataAddr);
112
113 ++DataAddr;
114 ++LoadAddr;
115 --BytesRemaining;
116 }
117
118 dbgs() << "\n";
119}
120#endif
121
122// Resolve the relocations for all symbols we currently know about.
123void RuntimeDyldImpl::resolveRelocations() {
124 std::lock_guard<sys::Mutex> locked(lock);
125
126 // Print out the sections prior to relocation.
127 LLVM_DEBUG(for (int i = 0, e = Sections.size(); i != e; ++i)do { } while (false)
128 dumpSectionMemory(Sections[i], "before relocations");)do { } while (false);
129
130 // First, resolve relocations associated with external symbols.
131 if (auto Err = resolveExternalSymbols()) {
132 HasError = true;
133 ErrorStr = toString(std::move(Err));
134 }
135
136 resolveLocalRelocations();
137
138 // Print out sections after relocation.
139 LLVM_DEBUG(for (int i = 0, e = Sections.size(); i != e; ++i)do { } while (false)
140 dumpSectionMemory(Sections[i], "after relocations");)do { } while (false);
141}
142
143void RuntimeDyldImpl::resolveLocalRelocations() {
144 // Iterate over all outstanding relocations
145 for (auto it = Relocations.begin(), e = Relocations.end(); it != e; ++it) {
146 // The Section here (Sections[i]) refers to the section in which the
147 // symbol for the relocation is located. The SectionID in the relocation
148 // entry provides the section to which the relocation will be applied.
149 unsigned Idx = it->first;
150 uint64_t Addr = getSectionLoadAddress(Idx);
151 LLVM_DEBUG(dbgs() << "Resolving relocations Section #" << Idx << "\t"do { } while (false)
152 << format("%p", (uintptr_t)Addr) << "\n")do { } while (false);
153 resolveRelocationList(it->second, Addr);
154 }
155 Relocations.clear();
156}
157
158void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
159 uint64_t TargetAddress) {
160 std::lock_guard<sys::Mutex> locked(lock);
161 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
162 if (Sections[i].getAddress() == LocalAddress) {
163 reassignSectionAddress(i, TargetAddress);
164 return;
165 }
166 }
167 llvm_unreachable("Attempting to remap address of unknown section!")__builtin_unreachable();
168}
169
170static Error getOffset(const SymbolRef &Sym, SectionRef Sec,
171 uint64_t &Result) {
172 Expected<uint64_t> AddressOrErr = Sym.getAddress();
173 if (!AddressOrErr)
174 return AddressOrErr.takeError();
175 Result = *AddressOrErr - Sec.getAddress();
176 return Error::success();
177}
178
179Expected<RuntimeDyldImpl::ObjSectionToIDMap>
180RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
181 std::lock_guard<sys::Mutex> locked(lock);
182
183 // Save information about our target
184 Arch = (Triple::ArchType)Obj.getArch();
185 IsTargetLittleEndian = Obj.isLittleEndian();
186 setMipsABI(Obj);
187
188 // Compute the memory size required to load all sections to be loaded
189 // and pass this information to the memory manager
190 if (MemMgr.needsToReserveAllocationSpace()) {
191 uint64_t CodeSize = 0, RODataSize = 0, RWDataSize = 0;
192 uint32_t CodeAlign = 1, RODataAlign = 1, RWDataAlign = 1;
193 if (auto Err = computeTotalAllocSize(Obj,
194 CodeSize, CodeAlign,
195 RODataSize, RODataAlign,
196 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(*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")do { } while (false);
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(*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(Name))
276 continue;
277
278 // If we're not responsible for this symbol, skip it.
279 if (!ResponsibilitySet.count(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(CommonSize, Align) + Size;
293 CommonSymbolsToAllocate.push_back(*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: " << Namedo { } while (false)
308 << " SID: " << SectionIDdo { } while (false)
309 << " Offset: " << format("%p", (uintptr_t)Addr)do { } while (false)
310 << " flags: " << *FlagsOrErr << "\n")do { } while (false);
311 if (!Name.empty()) // Skip absolute symbol relocations.
312 GlobalSymbolTable[Name] =
313 SymbolTableEntry(SectionID, Addr, *JITSymFlags);
314 } else if (SymType == object::SymbolRef::ST_Function ||
315 SymType == object::SymbolRef::ST_Data ||
316 SymType == object::SymbolRef::ST_Unknown ||
317 SymType == object::SymbolRef::ST_Other) {
318
319 section_iterator SI = Obj.section_end();
320 if (auto SIOrErr = I->getSection())
321 SI = *SIOrErr;
322 else
323 return SIOrErr.takeError();
324
325 if (SI == Obj.section_end())
326 continue;
327
328 // Get symbol offset.
329 uint64_t SectOffset;
330 if (auto Err = getOffset(*I, *SI, SectOffset))
331 return std::move(Err);
332
333 bool IsCode = SI->isText();
334 unsigned SectionID;
335 if (auto SectionIDOrErr =
336 findOrEmitSection(Obj, *SI, IsCode, LocalSections))
337 SectionID = *SectionIDOrErr;
338 else
339 return SectionIDOrErr.takeError();
340
341 LLVM_DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Namedo { } while (false)
342 << " SID: " << SectionIDdo { } while (false)
343 << " Offset: " << format("%p", (uintptr_t)SectOffset)do { } while (false)
344 << " flags: " << *FlagsOrErr << "\n")do { } while (false);
345 if (!Name.empty()) // Skip absolute symbol relocations
346 GlobalSymbolTable[Name] =
347 SymbolTableEntry(SectionID, SectOffset, *JITSymFlags);
348 }
349 }
350
351 // Allocate common symbols
352 if (auto Err = emitCommonSymbols(Obj, CommonSymbolsToAllocate, CommonSize,
353 CommonAlign))
354 return std::move(Err);
355
356 // Parse and process relocations
357 LLVM_DEBUG(dbgs() << "Parse relocations:\n")do { } while (false);
358 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
359 SI != SE; ++SI) {
360 StubMap Stubs;
361
362 Expected<section_iterator> RelSecOrErr = SI->getRelocatedSection();
363 if (!RelSecOrErr)
364 return RelSecOrErr.takeError();
365
366 section_iterator RelocatedSection = *RelSecOrErr;
367 if (RelocatedSection == SE)
368 continue;
369
370 relocation_iterator I = SI->relocation_begin();
371 relocation_iterator E = SI->relocation_end();
372
373 if (I == E && !ProcessAllSections)
374 continue;
375
376 bool IsCode = RelocatedSection->isText();
377 unsigned SectionID = 0;
378 if (auto SectionIDOrErr = findOrEmitSection(Obj, *RelocatedSection, IsCode,
379 LocalSections))
380 SectionID = *SectionIDOrErr;
381 else
382 return SectionIDOrErr.takeError();
383
384 LLVM_DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n")do { } while (false);
385
386 for (; I != E;)
387 if (auto IOrErr = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs))
388 I = *IOrErr;
389 else
390 return IOrErr.takeError();
391
392 // If there is a NotifyStubEmitted callback set, call it to register any
393 // stubs created for this section.
394 if (NotifyStubEmitted) {
395 StringRef FileName = Obj.getFileName();
396 StringRef SectionName = Sections[SectionID].getName();
397 for (auto &KV : Stubs) {
398
399 auto &VR = KV.first;
400 uint64_t StubAddr = KV.second;
401
402 // If this is a named stub, just call NotifyStubEmitted.
403 if (VR.SymbolName) {
404 NotifyStubEmitted(FileName, SectionName, VR.SymbolName, SectionID,
405 StubAddr);
406 continue;
407 }
408
409 // Otherwise we will have to try a reverse lookup on the globla symbol table.
410 for (auto &GSTMapEntry : GlobalSymbolTable) {
411 StringRef SymbolName = GSTMapEntry.first();
412 auto &GSTEntry = GSTMapEntry.second;
413 if (GSTEntry.getSectionID() == VR.SectionID &&
414 GSTEntry.getOffset() == VR.Offset) {
415 NotifyStubEmitted(FileName, SectionName, SymbolName, SectionID,
416 StubAddr);
417 break;
418 }
419 }
420 }
421 }
422 }
423
424 // Process remaining sections
425 if (ProcessAllSections) {
426 LLVM_DEBUG(dbgs() << "Process remaining sections:\n")do { } while (false);
427 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
428 SI != SE; ++SI) {
429
430 /* Ignore already loaded sections */
431 if (LocalSections.find(*SI) != LocalSections.end())
432 continue;
433
434 bool IsCode = SI->isText();
435 if (auto SectionIDOrErr =
436 findOrEmitSection(Obj, *SI, IsCode, LocalSections))
437 LLVM_DEBUG(dbgs() << "\tSectionID: " << (*SectionIDOrErr) << "\n")do { } while (false);
438 else
439 return SectionIDOrErr.takeError();
440 }
441 }
442
443 // Give the subclasses a chance to tie-up any loose ends.
444 if (auto Err = finalizeLoad(Obj, LocalSections))
445 return std::move(Err);
446
447// for (auto E : LocalSections)
448// llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
449
450 return LocalSections;
451}
452
453// A helper method for computeTotalAllocSize.
454// Computes the memory size required to allocate sections with the given sizes,
455// assuming that all sections are allocated with the given alignment
456static uint64_t
457computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
458 uint64_t Alignment) {
459 uint64_t TotalSize = 0;
460 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
461 uint64_t AlignedSize =
462 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
463 TotalSize += AlignedSize;
464 }
465 return TotalSize;
466}
467
468static bool isRequiredForExecution(const SectionRef Section) {
469 const ObjectFile *Obj = Section.getObject();
470 if (isa<object::ELFObjectFileBase>(Obj))
471 return ELFSectionRef(Section).getFlags() & ELF::SHF_ALLOC;
472 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) {
473 const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
474 // Avoid loading zero-sized COFF sections.
475 // In PE files, VirtualSize gives the section size, and SizeOfRawData
476 // may be zero for sections with content. In Obj files, SizeOfRawData
477 // gives the section size, and VirtualSize is always zero. Hence
478 // the need to check for both cases below.
479 bool HasContent =
480 (CoffSection->VirtualSize > 0) || (CoffSection->SizeOfRawData > 0);
481 bool IsDiscardable =
482 CoffSection->Characteristics &
483 (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
484 return HasContent && !IsDiscardable;
485 }
486
487 assert(isa<MachOObjectFile>(Obj))(static_cast<void> (0));
488 return true;
489}
490
491static bool isReadOnlyData(const SectionRef Section) {
492 const ObjectFile *Obj = Section.getObject();
493 if (isa<object::ELFObjectFileBase>(Obj))
494 return !(ELFSectionRef(Section).getFlags() &
495 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
496 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
497 return ((COFFObj->getCOFFSection(Section)->Characteristics &
498 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
499 | COFF::IMAGE_SCN_MEM_READ
500 | COFF::IMAGE_SCN_MEM_WRITE))
501 ==
502 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
503 | COFF::IMAGE_SCN_MEM_READ));
504
505 assert(isa<MachOObjectFile>(Obj))(static_cast<void> (0));
506 return false;
507}
508
509static bool isZeroInit(const SectionRef Section) {
510 const ObjectFile *Obj = Section.getObject();
511 if (isa<object::ELFObjectFileBase>(Obj))
512 return ELFSectionRef(Section).getType() == ELF::SHT_NOBITS;
513 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
514 return COFFObj->getCOFFSection(Section)->Characteristics &
515 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
516
517 auto *MachO = cast<MachOObjectFile>(Obj);
518 unsigned SectionType = MachO->getSectionType(Section);
519 return SectionType == MachO::S_ZEROFILL ||
520 SectionType == MachO::S_GB_ZEROFILL;
521}
522
523// Compute an upper bound of the memory size that is required to load all
524// sections
525Error RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
526 uint64_t &CodeSize,
527 uint32_t &CodeAlign,
528 uint64_t &RODataSize,
529 uint32_t &RODataAlign,
530 uint64_t &RWDataSize,
531 uint32_t &RWDataAlign) {
532 // Compute the size of all sections required for execution
533 std::vector<uint64_t> CodeSectionSizes;
534 std::vector<uint64_t> ROSectionSizes;
535 std::vector<uint64_t> RWSectionSizes;
536
537 // Collect sizes of all sections to be loaded;
538 // also determine the max alignment of all sections
539 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
540 SI != SE; ++SI) {
541 const SectionRef &Section = *SI;
542
543 bool IsRequired = isRequiredForExecution(Section) || ProcessAllSections;
544
545 // Consider only the sections that are required to be loaded for execution
546 if (IsRequired) {
547 uint64_t DataSize = Section.getSize();
548 uint64_t Alignment64 = Section.getAlignment();
549 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
550 bool IsCode = Section.isText();
551 bool IsReadOnly = isReadOnlyData(Section);
552
553 Expected<StringRef> NameOrErr = Section.getName();
554 if (!NameOrErr)
555 return NameOrErr.takeError();
556 StringRef Name = *NameOrErr;
557
558 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
559
560 uint64_t PaddingSize = 0;
561 if (Name == ".eh_frame")
562 PaddingSize += 4;
563 if (StubBufSize != 0)
564 PaddingSize += getStubAlignment() - 1;
565
566 uint64_t SectionSize = DataSize + PaddingSize + StubBufSize;
567
568 // The .eh_frame section (at least on Linux) needs an extra four bytes
569 // padded
570 // with zeroes added at the end. For MachO objects, this section has a
571 // slightly different name, so this won't have any effect for MachO
572 // objects.
573 if (Name == ".eh_frame")
574 SectionSize += 4;
575
576 if (!SectionSize)
577 SectionSize = 1;
578
579 if (IsCode) {
580 CodeAlign = std::max(CodeAlign, Alignment);
581 CodeSectionSizes.push_back(SectionSize);
582 } else if (IsReadOnly) {
583 RODataAlign = std::max(RODataAlign, Alignment);
584 ROSectionSizes.push_back(SectionSize);
585 } else {
586 RWDataAlign = std::max(RWDataAlign, Alignment);
587 RWSectionSizes.push_back(SectionSize);
588 }
589 }
590 }
591
592 // Compute Global Offset Table size. If it is not zero we
593 // also update alignment, which is equal to a size of a
594 // single GOT entry.
595 if (unsigned GotSize = computeGOTSize(Obj)) {
596 RWSectionSizes.push_back(GotSize);
597 RWDataAlign = std::max<uint32_t>(RWDataAlign, getGOTEntrySize());
598 }
599
600 // Compute the size of all common symbols
601 uint64_t CommonSize = 0;
602 uint32_t CommonAlign = 1;
603 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
604 ++I) {
605 Expected<uint32_t> FlagsOrErr = I->getFlags();
606 if (!FlagsOrErr)
607 // TODO: Test this error.
608 return FlagsOrErr.takeError();
609 if (*FlagsOrErr & SymbolRef::SF_Common) {
610 // Add the common symbols to a list. We'll allocate them all below.
611 uint64_t Size = I->getCommonSize();
612 uint32_t Align = I->getAlignment();
613 // If this is the first common symbol, use its alignment as the alignment
614 // for the common symbols section.
615 if (CommonSize == 0)
616 CommonAlign = Align;
617 CommonSize = alignTo(CommonSize, Align) + Size;
618 }
619 }
620 if (CommonSize != 0) {
621 RWSectionSizes.push_back(CommonSize);
622 RWDataAlign = std::max(RWDataAlign, CommonAlign);
623 }
624
625 // Compute the required allocation space for each different type of sections
626 // (code, read-only data, read-write data) assuming that all sections are
627 // allocated with the max alignment. Note that we cannot compute with the
628 // individual alignments of the sections, because then the required size
629 // depends on the order, in which the sections are allocated.
630 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, CodeAlign);
631 RODataSize = computeAllocationSizeForSections(ROSectionSizes, RODataAlign);
632 RWDataSize = computeAllocationSizeForSections(RWSectionSizes, RWDataAlign);
633
634 return Error::success();
635}
636
637// compute GOT size
638unsigned RuntimeDyldImpl::computeGOTSize(const ObjectFile &Obj) {
639 size_t GotEntrySize = getGOTEntrySize();
640 if (!GotEntrySize)
641 return 0;
642
643 size_t GotSize = 0;
644 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
645 SI != SE; ++SI) {
646
647 for (const RelocationRef &Reloc : SI->relocations())
648 if (relocationNeedsGot(Reloc))
649 GotSize += GotEntrySize;
650 }
651
652 return GotSize;
653}
654
655// compute stub buffer size for the given section
656unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
657 const SectionRef &Section) {
658 if (!MemMgr.allowStubAllocation()) {
659 return 0;
660 }
661
662 unsigned StubSize = getMaxStubSize();
663 if (StubSize == 0) {
664 return 0;
665 }
666 // FIXME: this is an inefficient way to handle this. We should computed the
667 // necessary section allocation size in loadObject by walking all the sections
668 // once.
669 unsigned StubBufSize = 0;
670 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
671 SI != SE; ++SI) {
672
673 Expected<section_iterator> RelSecOrErr = SI->getRelocatedSection();
674 if (!RelSecOrErr)
675 report_fatal_error(toString(RelSecOrErr.takeError()));
676
677 section_iterator RelSecI = *RelSecOrErr;
678 if (!(RelSecI == Section))
679 continue;
680
681 for (const RelocationRef &Reloc : SI->relocations())
682 if (relocationNeedsStub(Reloc))
683 StubBufSize += StubSize;
684 }
685
686 // Get section data size and alignment
687 uint64_t DataSize = Section.getSize();
688 uint64_t Alignment64 = Section.getAlignment();
689
690 // Add stubbuf size alignment
691 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
692 unsigned StubAlignment = getStubAlignment();
693 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
694 if (StubAlignment > EndAlignment)
695 StubBufSize += StubAlignment - EndAlignment;
696 return StubBufSize;
697}
698
699uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
700 unsigned Size) const {
701 uint64_t Result = 0;
702 if (IsTargetLittleEndian) {
703 Src += Size - 1;
704 while (Size--)
705 Result = (Result << 8) | *Src--;
706 } else
707 while (Size--)
708 Result = (Result << 8) | *Src++;
709
710 return Result;
711}
712
713void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
714 unsigned Size) const {
715 if (IsTargetLittleEndian) {
716 while (Size--) {
717 *Dst++ = Value & 0xFF;
718 Value >>= 8;
719 }
720 } else {
721 Dst += Size - 1;
722 while (Size--) {
723 *Dst-- = Value & 0xFF;
724 Value >>= 8;
725 }
726 }
727}
728
729Expected<JITSymbolFlags>
730RuntimeDyldImpl::getJITSymbolFlags(const SymbolRef &SR) {
731 return JITSymbolFlags::fromObjectSymbol(SR);
732}
733
734Error RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
735 CommonSymbolList &SymbolsToAllocate,
736 uint64_t CommonSize,
737 uint32_t CommonAlign) {
738 if (SymbolsToAllocate.empty())
739 return Error::success();
740
741 // Allocate memory for the section
742 unsigned SectionID = Sections.size();
743 uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, CommonAlign, SectionID,
744 "<common symbols>", false);
745 if (!Addr)
746 report_fatal_error("Unable to allocate memory for common symbols!");
747 uint64_t Offset = 0;
748 Sections.push_back(
749 SectionEntry("<common symbols>", Addr, CommonSize, CommonSize, 0));
750 memset(Addr, 0, CommonSize);
751
752 LLVM_DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionIDdo { } while (false)
753 << " new addr: " << format("%p", Addr)do { } while (false)
754 << " DataSize: " << CommonSize << "\n")do { } while (false);
755
756 // Assign the address of each symbol
757 for (auto &Sym : SymbolsToAllocate) {
758 uint32_t Alignment = Sym.getAlignment();
759 uint64_t Size = Sym.getCommonSize();
760 StringRef Name;
761 if (auto NameOrErr = Sym.getName())
762 Name = *NameOrErr;
763 else
764 return NameOrErr.takeError();
765 if (Alignment) {
766 // This symbol has an alignment requirement.
767 uint64_t AlignOffset =
768 offsetToAlignment((uint64_t)Addr, Align(Alignment));
769 Addr += AlignOffset;
770 Offset += AlignOffset;
771 }
772 auto JITSymFlags = getJITSymbolFlags(Sym);
773
774 if (!JITSymFlags)
775 return JITSymFlags.takeError();
776
777 LLVM_DEBUG(dbgs() << "Allocating common symbol " << Name << " address "do { } while (false)
778 << format("%p", Addr) << "\n")do { } while (false);
779 if (!Name.empty()) // Skip absolute symbol relocations.
780 GlobalSymbolTable[Name] =
781 SymbolTableEntry(SectionID, Offset, std::move(*JITSymFlags));
782 Offset += Size;
783 Addr += Size;
784 }
785
786 return Error::success();
787}
788
789Expected<unsigned>
790RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
791 const SectionRef &Section,
792 bool IsCode) {
793 StringRef data;
794 uint64_t Alignment64 = Section.getAlignment();
795
796 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
797 unsigned PaddingSize = 0;
798 unsigned StubBufSize = 0;
799 bool IsRequired = isRequiredForExecution(Section);
800 bool IsVirtual = Section.isVirtual();
801 bool IsZeroInit = isZeroInit(Section);
802 bool IsReadOnly = isReadOnlyData(Section);
803 uint64_t DataSize = Section.getSize();
804
805 // An alignment of 0 (at least with ELF) is identical to an alignment of 1,
806 // while being more "polite". Other formats do not support 0-aligned sections
807 // anyway, so we should guarantee that the alignment is always at least 1.
808 Alignment = std::max(1u, Alignment);
809
810 Expected<StringRef> NameOrErr = Section.getName();
811 if (!NameOrErr)
812 return NameOrErr.takeError();
813 StringRef Name = *NameOrErr;
814
815 StubBufSize = computeSectionStubBufSize(Obj, Section);
816
817 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
818 // with zeroes added at the end. For MachO objects, this section has a
819 // slightly different name, so this won't have any effect for MachO objects.
820 if (Name == ".eh_frame")
821 PaddingSize = 4;
822
823 uintptr_t Allocate;
824 unsigned SectionID = Sections.size();
825 uint8_t *Addr;
826 const char *pData = nullptr;
827
828 // If this section contains any bits (i.e. isn't a virtual or bss section),
829 // grab a reference to them.
830 if (!IsVirtual && !IsZeroInit) {
831 // In either case, set the location of the unrelocated section in memory,
832 // since we still process relocations for it even if we're not applying them.
833 if (Expected<StringRef> E = Section.getContents())
834 data = *E;
835 else
836 return E.takeError();
837 pData = data.data();
838 }
839
840 // If there are any stubs then the section alignment needs to be at least as
841 // high as stub alignment or padding calculations may by incorrect when the
842 // section is remapped.
843 if (StubBufSize != 0) {
844 Alignment = std::max(Alignment, getStubAlignment());
845 PaddingSize += getStubAlignment() - 1;
846 }
847
848 // Some sections, such as debug info, don't need to be loaded for execution.
849 // Process those only if explicitly requested.
850 if (IsRequired || ProcessAllSections) {
851 Allocate = DataSize + PaddingSize + StubBufSize;
852 if (!Allocate)
853 Allocate = 1;
854 Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID,
855 Name)
856 : MemMgr.allocateDataSection(Allocate, Alignment, SectionID,
857 Name, IsReadOnly);
858 if (!Addr)
859 report_fatal_error("Unable to allocate section memory!");
860
861 // Zero-initialize or copy the data from the image
862 if (IsZeroInit || IsVirtual)
863 memset(Addr, 0, DataSize);
864 else
865 memcpy(Addr, pData, DataSize);
866
867 // Fill in any extra bytes we allocated for padding
868 if (PaddingSize != 0) {
869 memset(Addr + DataSize, 0, PaddingSize);
870 // Update the DataSize variable to include padding.
871 DataSize += PaddingSize;
872
873 // Align DataSize to stub alignment if we have any stubs (PaddingSize will
874 // have been increased above to account for this).
875 if (StubBufSize > 0)
876 DataSize &= -(uint64_t)getStubAlignment();
877 }
878
879 LLVM_DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: "do { } while (false)
880 << Name << " obj addr: " << format("%p", pData)do { } while (false)
881 << " new addr: " << format("%p", Addr) << " DataSize: "do { } while (false)
882 << DataSize << " StubBufSize: " << StubBufSizedo { } while (false)
883 << " Allocate: " << Allocate << "\n")do { } while (false);
884 } else {
885 // Even if we didn't load the section, we need to record an entry for it
886 // to handle later processing (and by 'handle' I mean don't do anything
887 // with these sections).
888 Allocate = 0;
889 Addr = nullptr;
890 LLVM_DEBUG(do { } while (false)
891 dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Namedo { } while (false)
892 << " obj addr: " << format("%p", data.data()) << " new addr: 0"do { } while (false)
893 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSizedo { } while (false)
894 << " Allocate: " << Allocate << "\n")do { } while (false);
895 }
896
897 Sections.push_back(
898 SectionEntry(Name, Addr, DataSize, Allocate, (uintptr_t)pData));
899
900 // Debug info sections are linked as if their load address was zero
901 if (!IsRequired)
902 Sections.back().setLoadAddress(0);
903
904 return SectionID;
905}
906
907Expected<unsigned>
908RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
909 const SectionRef &Section,
910 bool IsCode,
911 ObjSectionToIDMap &LocalSections) {
912
913 unsigned SectionID = 0;
914 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
915 if (i != LocalSections.end())
916 SectionID = i->second;
917 else {
918 if (auto SectionIDOrErr = emitSection(Obj, Section, IsCode))
919 SectionID = *SectionIDOrErr;
920 else
921 return SectionIDOrErr.takeError();
922 LocalSections[Section] = SectionID;
923 }
924 return SectionID;
925}
926
927void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
928 unsigned SectionID) {
929 Relocations[SectionID].push_back(RE);
930}
931
932void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
933 StringRef SymbolName) {
934 // Relocation by symbol. If the symbol is found in the global symbol table,
935 // create an appropriate section relocation. Otherwise, add it to
936 // ExternalSymbolRelocations.
937 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
938 if (Loc == GlobalSymbolTable.end()) {
939 ExternalSymbolRelocations[SymbolName].push_back(RE);
940 } else {
941 assert(!SymbolName.empty() &&(static_cast<void> (0))
942 "Empty symbol should not be in GlobalSymbolTable")(static_cast<void> (0));
943 // Copy the RE since we want to modify its addend.
944 RelocationEntry RECopy = RE;
945 const auto &SymInfo = Loc->second;
946 RECopy.Addend += SymInfo.getOffset();
947 Relocations[SymInfo.getSectionID()].push_back(RECopy);
948 }
949}
950
951uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
952 unsigned AbiVariant) {
953 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be ||
954 Arch == Triple::aarch64_32) {
955 // This stub has to be able to access the full address space,
956 // since symbol lookup won't necessarily find a handy, in-range,
957 // PLT stub for functions which could be anywhere.
958 // Stub can use ip0 (== x16) to calculate address
959 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
960 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
961 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
962 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
963 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
964
965 return Addr;
966 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
967 // TODO: There is only ARM far stub now. We should add the Thumb stub,
968 // and stubs for branches Thumb - ARM and ARM - Thumb.
969 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc, [pc, #-4]
970 return Addr + 4;
971 } else if (IsMipsO32ABI || IsMipsN32ABI) {
972 // 0: 3c190000 lui t9,%hi(addr).
973 // 4: 27390000 addiu t9,t9,%lo(addr).
974 // 8: 03200008 jr t9.
975 // c: 00000000 nop.
976 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
977 const unsigned NopInstr = 0x0;
978 unsigned JrT9Instr = 0x03200008;
979 if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_32R6 ||
980 (AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
981 JrT9Instr = 0x03200009;
982
983 writeBytesUnaligned(LuiT9Instr, Addr, 4);
984 writeBytesUnaligned(AdduiT9Instr, Addr + 4, 4);
985 writeBytesUnaligned(JrT9Instr, Addr + 8, 4);
986 writeBytesUnaligned(NopInstr, Addr + 12, 4);
987 return Addr;
988 } else if (IsMipsN64ABI) {
989 // 0: 3c190000 lui t9,%highest(addr).
990 // 4: 67390000 daddiu t9,t9,%higher(addr).
991 // 8: 0019CC38 dsll t9,t9,16.
992 // c: 67390000 daddiu t9,t9,%hi(addr).
993 // 10: 0019CC38 dsll t9,t9,16.
994 // 14: 67390000 daddiu t9,t9,%lo(addr).
995 // 18: 03200008 jr t9.
996 // 1c: 00000000 nop.
997 const unsigned LuiT9Instr = 0x3c190000, DaddiuT9Instr = 0x67390000,
998 DsllT9Instr = 0x19CC38;
999 const unsigned NopInstr = 0x0;
1000 unsigned JrT9Instr = 0x03200008;
1001 if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_64R6)
1002 JrT9Instr = 0x03200009;
1003
1004 writeBytesUnaligned(LuiT9Instr, Addr, 4);
1005 writeBytesUnaligned(DaddiuT9Instr, Addr + 4, 4);
1006 writeBytesUnaligned(DsllT9Instr, Addr + 8, 4);
1007 writeBytesUnaligned(DaddiuT9Instr, Addr + 12, 4);
1008 writeBytesUnaligned(DsllT9Instr, Addr + 16, 4);
1009 writeBytesUnaligned(DaddiuT9Instr, Addr + 20, 4);
1010 writeBytesUnaligned(JrT9Instr, Addr + 24, 4);
1011 writeBytesUnaligned(NopInstr, Addr + 28, 4);
1012 return Addr;
1013 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
1014 // Depending on which version of the ELF ABI is in use, we need to
1015 // generate one of two variants of the stub. They both start with
1016 // the same sequence to load the target address into r12.
1017 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
1018 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
1019 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
1020 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
1021 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
1022 if (AbiVariant == 2) {
1023 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
1024 // The address is already in r12 as required by the ABI. Branch to it.
1025 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
1026 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
1027 writeInt32BE(Addr+28, 0x4E800420); // bctr
1028 } else {
1029 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
1030 // Load the function address on r11 and sets it to control register. Also
1031 // loads the function TOC in r2 and environment pointer to r11.
1032 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
1033 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
1034 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
1035 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
1036 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
1037 writeInt32BE(Addr+40, 0x4E800420); // bctr
1038 }
1039 return Addr;
1040 } else if (Arch == Triple::systemz) {
1041 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
1042 writeInt16BE(Addr+2, 0x0000);
1043 writeInt16BE(Addr+4, 0x0004);
1044 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
1045 // 8-byte address stored at Addr + 8
1046 return Addr;
1047 } else if (Arch == Triple::x86_64) {
1048 *Addr = 0xFF; // jmp
1049 *(Addr+1) = 0x25; // rip
1050 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
1051 } else if (Arch == Triple::x86) {
1052 *Addr = 0xE9; // 32-bit pc-relative jump.
1053 }
1054 return Addr;
1055}
1056
1057// Assign an address to a symbol name and resolve all the relocations
1058// associated with it.
1059void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
1060 uint64_t Addr) {
1061 // The address to use for relocation resolution is not
1062 // the address of the local section buffer. We must be doing
1063 // a remote execution environment of some sort. Relocations can't
1064 // be applied until all the sections have been moved. The client must
1065 // trigger this with a call to MCJIT::finalize() or
1066 // RuntimeDyld::resolveRelocations().
1067 //
1068 // Addr is a uint64_t because we can't assume the pointer width
1069 // of the target is the same as that of the host. Just use a generic
1070 // "big enough" type.
1071 LLVM_DEBUG(do { } while (false)
1072 dbgs() << "Reassigning address for section " << SectionID << " ("do { } while (false)
1073 << Sections[SectionID].getName() << "): "do { } while (false)
1074 << format("0x%016" PRIx64, Sections[SectionID].getLoadAddress())do { } while (false)
1075 << " -> " << format("0x%016" PRIx64, Addr) << "\n")do { } while (false);
1076 Sections[SectionID].setLoadAddress(Addr);
1077}
1078
1079void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
1080 uint64_t Value) {
1081 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
1082 const RelocationEntry &RE = Relocs[i];
1083 // Ignore relocations for sections that were not loaded
1084 if (RE.SectionID != AbsoluteSymbolSection &&
1085 Sections[RE.SectionID].getAddress() == nullptr)
1086 continue;
1087 resolveRelocation(RE, Value);
1088 }
1089}
1090
1091void RuntimeDyldImpl::applyExternalSymbolRelocations(
1092 const StringMap<JITEvaluatedSymbol> ExternalSymbolMap) {
1093 for (auto &RelocKV : ExternalSymbolRelocations) {
1094 StringRef Name = RelocKV.first();
1095 RelocationList &Relocs = RelocKV.second;
1096 if (Name.size() == 0) {
1097 // This is an absolute symbol, use an address of zero.
1098 LLVM_DEBUG(dbgs() << "Resolving absolute relocations."do { } while (false)
1099 << "\n")do { } while (false);
1100 resolveRelocationList(Relocs, 0);
1101 } else {
1102 uint64_t Addr = 0;
1103 JITSymbolFlags Flags;
1104 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
1105 if (Loc == GlobalSymbolTable.end()) {
1106 auto RRI = ExternalSymbolMap.find(Name);
1107 assert(RRI != ExternalSymbolMap.end() && "No result for symbol")(static_cast<void> (0));
1108 Addr = RRI->second.getAddress();
1109 Flags = RRI->second.getFlags();
1110 } else {
1111 // We found the symbol in our global table. It was probably in a
1112 // Module that we loaded previously.
1113 const auto &SymInfo = Loc->second;
1114 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
1115 SymInfo.getOffset();
1116 Flags = SymInfo.getFlags();
1117 }
1118
1119 // FIXME: Implement error handling that doesn't kill the host program!
1120 if (!Addr && !Resolver.allowsZeroSymbols())
1121 report_fatal_error("Program used external function '" + Name +
1122 "' which could not be resolved!");
1123
1124 // If Resolver returned UINT64_MAX, the client wants to handle this symbol
1125 // manually and we shouldn't resolve its relocations.
1126 if (Addr != UINT64_MAX(18446744073709551615UL)) {
1127
1128 // Tweak the address based on the symbol flags if necessary.
1129 // For example, this is used by RuntimeDyldMachOARM to toggle the low bit
1130 // if the target symbol is Thumb.
1131 Addr = modifyAddressBasedOnFlags(Addr, Flags);
1132
1133 LLVM_DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"do { } while (false)
1134 << format("0x%lx", Addr) << "\n")do { } while (false);
1135 resolveRelocationList(Relocs, Addr);
1136 }
1137 }
1138 }
1139 ExternalSymbolRelocations.clear();
1140}
1141
1142Error RuntimeDyldImpl::resolveExternalSymbols() {
1143 StringMap<JITEvaluatedSymbol> ExternalSymbolMap;
1144
1145 // Resolution can trigger emission of more symbols, so iterate until
1146 // we've resolved *everything*.
1147 {
1148 JITSymbolResolver::LookupSet ResolvedSymbols;
1149
1150 while (true) {
1151 JITSymbolResolver::LookupSet NewSymbols;
1152
1153 for (auto &RelocKV : ExternalSymbolRelocations) {
1154 StringRef Name = RelocKV.first();
1155 if (!Name.empty() && !GlobalSymbolTable.count(Name) &&
1156 !ResolvedSymbols.count(Name))
1157 NewSymbols.insert(Name);
1158 }
1159
1160 if (NewSymbols.empty())
1161 break;
1162
1163#ifdef _MSC_VER
1164 using ExpectedLookupResult =
1165 MSVCPExpected<JITSymbolResolver::LookupResult>;
1166#else
1167 using ExpectedLookupResult = Expected<JITSymbolResolver::LookupResult>;
1168#endif
1169
1170 auto NewSymbolsP = std::make_shared<std::promise<ExpectedLookupResult>>();
1171 auto NewSymbolsF = NewSymbolsP->get_future();
1172 Resolver.lookup(NewSymbols,
1173 [=](Expected<JITSymbolResolver::LookupResult> Result) {
1174 NewSymbolsP->set_value(std::move(Result));
1175 });
1176
1177 auto NewResolverResults = NewSymbolsF.get();
1178
1179 if (!NewResolverResults)
1180 return NewResolverResults.takeError();
1181
1182 assert(NewResolverResults->size() == NewSymbols.size() &&(static_cast<void> (0))
1183 "Should have errored on unresolved symbols")(static_cast<void> (0));
1184
1185 for (auto &RRKV : *NewResolverResults) {
1186 assert(!ResolvedSymbols.count(RRKV.first) && "Redundant resolution?")(static_cast<void> (0));
1187 ExternalSymbolMap.insert(RRKV);
1188 ResolvedSymbols.insert(RRKV.first);
1189 }
1190 }
1191 }
1192
1193 applyExternalSymbolRelocations(ExternalSymbolMap);
1194
1195 return Error::success();
1196}
1197
1198void RuntimeDyldImpl::finalizeAsync(
1199 std::unique_ptr<RuntimeDyldImpl> This,
1200 unique_function<void(object::OwningBinary<object::ObjectFile>,
1201 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>, Error)>
1202 OnEmitted,
1203 object::OwningBinary<object::ObjectFile> O,
1204 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> Info) {
1205
1206 auto SharedThis = std::shared_ptr<RuntimeDyldImpl>(std::move(This));
1207 auto PostResolveContinuation =
1208 [SharedThis, OnEmitted = std::move(OnEmitted), O = std::move(O),
1209 Info = std::move(Info)](
1210 Expected<JITSymbolResolver::LookupResult> Result) mutable {
1211 if (!Result) {
1212 OnEmitted(std::move(O), std::move(Info), Result.takeError());
1213 return;
1214 }
1215
1216 /// Copy the result into a StringMap, where the keys are held by value.
1217 StringMap<JITEvaluatedSymbol> Resolved;
1218 for (auto &KV : *Result)
1219 Resolved[KV.first] = KV.second;
1220
1221 SharedThis->applyExternalSymbolRelocations(Resolved);
1222 SharedThis->resolveLocalRelocations();
1223 SharedThis->registerEHFrames();
1224 std::string ErrMsg;
1225 if (SharedThis->MemMgr.finalizeMemory(&ErrMsg))
1226 OnEmitted(std::move(O), std::move(Info),
1227 make_error<StringError>(std::move(ErrMsg),
1228 inconvertibleErrorCode()));
1229 else
1230 OnEmitted(std::move(O), std::move(Info), Error::success());
1231 };
1232
1233 JITSymbolResolver::LookupSet Symbols;
1234
1235 for (auto &RelocKV : SharedThis->ExternalSymbolRelocations) {
1236 StringRef Name = RelocKV.first();
1237 if (Name.empty()) // Skip absolute symbol relocations.
1238 continue;
1239 assert(!SharedThis->GlobalSymbolTable.count(Name) &&(static_cast<void> (0))
1240 "Name already processed. RuntimeDyld instances can not be re-used "(static_cast<void> (0))
1241 "when finalizing with finalizeAsync.")(static_cast<void> (0));
1242 Symbols.insert(Name);
1243 }
1244
1245 if (!Symbols.empty()) {
1246 SharedThis->Resolver.lookup(Symbols, std::move(PostResolveContinuation));
1247 } else
1248 PostResolveContinuation(std::map<StringRef, JITEvaluatedSymbol>());
1249}
1250
1251//===----------------------------------------------------------------------===//
1252// RuntimeDyld class implementation
1253
1254uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
1255 const object::SectionRef &Sec) const {
1256
1257 auto I = ObjSecToIDMap.find(Sec);
1258 if (I != ObjSecToIDMap.end())
1259 return RTDyld.Sections[I->second].getLoadAddress();
1260
1261 return 0;
1262}
1263
1264void RuntimeDyld::MemoryManager::anchor() {}
1265void JITSymbolResolver::anchor() {}
1266void LegacyJITSymbolResolver::anchor() {}
1267
1268RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
1269 JITSymbolResolver &Resolver)
1270 : MemMgr(MemMgr), Resolver(Resolver) {
1271 // FIXME: There's a potential issue lurking here if a single instance of
1272 // RuntimeDyld is used to load multiple objects. The current implementation
1273 // associates a single memory manager with a RuntimeDyld instance. Even
1274 // though the public class spawns a new 'impl' instance for each load,
1275 // they share a single memory manager. This can become a problem when page
1276 // permissions are applied.
1277 Dyld = nullptr;
1278 ProcessAllSections = false;
1279}
1280
1281RuntimeDyld::~RuntimeDyld() {}
1282
1283static std::unique_ptr<RuntimeDyldCOFF>
1284createRuntimeDyldCOFF(
1285 Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
1286 JITSymbolResolver &Resolver, bool ProcessAllSections,
1287 RuntimeDyld::NotifyStubEmittedFunction NotifyStubEmitted) {
1288 std::unique_ptr<RuntimeDyldCOFF> Dyld =
1289 RuntimeDyldCOFF::create(Arch, MM, Resolver);
1290 Dyld->setProcessAllSections(ProcessAllSections);
1291 Dyld->setNotifyStubEmitted(std::move(NotifyStubEmitted));
1292 return Dyld;
1293}
1294
1295static std::unique_ptr<RuntimeDyldELF>
1296createRuntimeDyldELF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
1297 JITSymbolResolver &Resolver, bool ProcessAllSections,
1298 RuntimeDyld::NotifyStubEmittedFunction NotifyStubEmitted) {
1299 std::unique_ptr<RuntimeDyldELF> Dyld =
1300 RuntimeDyldELF::create(Arch, MM, Resolver);
1301 Dyld->setProcessAllSections(ProcessAllSections);
1302 Dyld->setNotifyStubEmitted(std::move(NotifyStubEmitted));
1303 return Dyld;
1304}
1305
1306static std::unique_ptr<RuntimeDyldMachO>
1307createRuntimeDyldMachO(
1308 Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
1309 JITSymbolResolver &Resolver,
1310 bool ProcessAllSections,
1311 RuntimeDyld::NotifyStubEmittedFunction NotifyStubEmitted) {
1312 std::unique_ptr<RuntimeDyldMachO> Dyld =
1313 RuntimeDyldMachO::create(Arch, MM, Resolver);
1314 Dyld->setProcessAllSections(ProcessAllSections);
1315 Dyld->setNotifyStubEmitted(std::move(NotifyStubEmitted));
1316 return Dyld;
1317}
1318
1319std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
1320RuntimeDyld::loadObject(const ObjectFile &Obj) {
1321 if (!Dyld) {
1322 if (Obj.isELF())
1323 Dyld =
1324 createRuntimeDyldELF(static_cast<Triple::ArchType>(Obj.getArch()),
1325 MemMgr, Resolver, ProcessAllSections,
1326 std::move(NotifyStubEmitted));
1327 else if (Obj.isMachO())
1328 Dyld = createRuntimeDyldMachO(
1329 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
1330 ProcessAllSections, std::move(NotifyStubEmitted));
1331 else if (Obj.isCOFF())
1332 Dyld = createRuntimeDyldCOFF(
1333 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
1334 ProcessAllSections, std::move(NotifyStubEmitted));
1335 else
1336 report_fatal_error("Incompatible object format!");
1337 }
1338
1339 if (!Dyld->isCompatibleFile(Obj))
1340 report_fatal_error("Incompatible object format!");
1341
1342 auto LoadedObjInfo = Dyld->loadObject(Obj);
1343 MemMgr.notifyObjectLoaded(*this, Obj);
1344 return LoadedObjInfo;
1345}
1346
1347void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
1348 if (!Dyld)
1349 return nullptr;
1350 return Dyld->getSymbolLocalAddress(Name);
1351}
1352
1353unsigned RuntimeDyld::getSymbolSectionID(StringRef Name) const {
1354 assert(Dyld && "No RuntimeDyld instance attached")(static_cast<void> (0));
1355 return Dyld->getSymbolSectionID(Name);
1356}
1357
1358JITEvaluatedSymbol RuntimeDyld::getSymbol(StringRef Name) const {
1359 if (!Dyld)
1360 return nullptr;
1361 return Dyld->getSymbol(Name);
1362}
1363
1364std::map<StringRef, JITEvaluatedSymbol> RuntimeDyld::getSymbolTable() const {
1365 if (!Dyld)
1366 return std::map<StringRef, JITEvaluatedSymbol>();
1367 return Dyld->getSymbolTable();
1368}
1369
1370void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
1371
1372void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
1373 Dyld->reassignSectionAddress(SectionID, Addr);
1374}
1375
1376void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
1377 uint64_t TargetAddress) {
1378 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
1379}
1380
1381bool RuntimeDyld::hasError() { return Dyld->hasError(); }
1382
1383StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
1384
1385void RuntimeDyld::finalizeWithMemoryManagerLocking() {
1386 bool MemoryFinalizationLocked = MemMgr.FinalizationLocked;
1387 MemMgr.FinalizationLocked = true;
1388 resolveRelocations();
1389 registerEHFrames();
1390 if (!MemoryFinalizationLocked) {
1391 MemMgr.finalizeMemory();
1392 MemMgr.FinalizationLocked = false;
1393 }
1394}
1395
1396StringRef RuntimeDyld::getSectionContent(unsigned SectionID) const {
1397 assert(Dyld && "No Dyld instance attached")(static_cast<void> (0));
1398 return Dyld->getSectionContent(SectionID);
1399}
1400
1401uint64_t RuntimeDyld::getSectionLoadAddress(unsigned SectionID) const {
1402 assert(Dyld && "No Dyld instance attached")(static_cast<void> (0));
1403 return Dyld->getSectionLoadAddress(SectionID);
1404}
1405
1406void RuntimeDyld::registerEHFrames() {
1407 if (Dyld)
1408 Dyld->registerEHFrames();
1409}
1410
1411void RuntimeDyld::deregisterEHFrames() {
1412 if (Dyld)
1413 Dyld->deregisterEHFrames();
1414}
1415// FIXME: Kill this with fire once we have a new JIT linker: this is only here
1416// so that we can re-use RuntimeDyld's implementation without twisting the
1417// interface any further for ORC's purposes.
1418void jitLinkForORC(
1419 object::OwningBinary<object::ObjectFile> O,
1420 RuntimeDyld::MemoryManager &MemMgr, JITSymbolResolver &Resolver,
1421 bool ProcessAllSections,
1422 unique_function<Error(const object::ObjectFile &Obj,
1423 RuntimeDyld::LoadedObjectInfo &LoadedObj,
1424 std::map<StringRef, JITEvaluatedSymbol>)>
1425 OnLoaded,
1426 unique_function<void(object::OwningBinary<object::ObjectFile>,
1427 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>, Error)>
1428 OnEmitted) {
1429
1430 RuntimeDyld RTDyld(MemMgr, Resolver);
1431 RTDyld.setProcessAllSections(ProcessAllSections);
1432
1433 auto Info = RTDyld.loadObject(*O.getBinary());
1434
1435 if (RTDyld.hasError()) {
1
Assuming the condition is false
2
Taking false branch
1436 OnEmitted(std::move(O), std::move(Info),
1437 make_error<StringError>(RTDyld.getErrorString(),
1438 inconvertibleErrorCode()));
1439 return;
1440 }
1441
1442 if (auto Err = OnLoaded(*O.getBinary(), *Info, RTDyld.getSymbolTable()))
3
Taking true branch
1443 OnEmitted(std::move(O), std::move(Info), std::move(Err));
4
Object 'O' is moved
1444
1445 RuntimeDyldImpl::finalizeAsync(std::move(RTDyld.Dyld), std::move(OnEmitted),
1446 std::move(O), std::move(Info));
5
Moved-from object 'O' is moved
1447}
1448
1449} // end namespace llvm