Bug Summary

File:lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
Location:line 413, column 3
Description:Undefined or garbage value returned to caller

Annotated Source Code

1//===-- RuntimeDyld.cpp - Run-time dynamic linker for MC-JIT ----*- C++ -*-===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// Implementation of the MC-JIT runtime dynamic linker.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/ExecutionEngine/RuntimeDyld.h"
15#include "JITRegistrar.h"
16#include "ObjectImageCommon.h"
17#include "RuntimeDyldCheckerImpl.h"
18#include "RuntimeDyldELF.h"
19#include "RuntimeDyldImpl.h"
20#include "RuntimeDyldMachO.h"
21#include "llvm/Object/ELF.h"
22#include "llvm/Support/MathExtras.h"
23#include "llvm/Support/MutexGuard.h"
24
25using namespace llvm;
26using namespace llvm::object;
27
28#define DEBUG_TYPE"dyld" "dyld"
29
30// Empty out-of-line virtual destructor as the key function.
31RuntimeDyldImpl::~RuntimeDyldImpl() {}
32
33// Pin the JITRegistrar's and ObjectImage*'s vtables to this file.
34void JITRegistrar::anchor() {}
35void ObjectImage::anchor() {}
36void ObjectImageCommon::anchor() {}
37
38namespace llvm {
39
40void RuntimeDyldImpl::registerEHFrames() {}
41
42void RuntimeDyldImpl::deregisterEHFrames() {}
43
44#ifndef NDEBUG
45static void dumpSectionMemory(const SectionEntry &S, StringRef State) {
46 dbgs() << "----- Contents of section " << S.Name << " " << State << " -----";
47
48 const unsigned ColsPerRow = 16;
49
50 uint8_t *DataAddr = S.Address;
51 uint64_t LoadAddr = S.LoadAddress;
52
53 unsigned StartPadding = LoadAddr & 7;
54 unsigned BytesRemaining = S.Size;
55
56 if (StartPadding) {
57 dbgs() << "\n" << format("0x%08x", LoadAddr & ~(ColsPerRow - 1)) << ":";
58 while (StartPadding--)
59 dbgs() << " ";
60 }
61
62 while (BytesRemaining > 0) {
63 if ((LoadAddr & (ColsPerRow - 1)) == 0)
64 dbgs() << "\n" << format("0x%016" PRIx64"l" "x", LoadAddr) << ":";
65
66 dbgs() << " " << format("%02x", *DataAddr);
67
68 ++DataAddr;
69 ++LoadAddr;
70 --BytesRemaining;
71 }
72
73 dbgs() << "\n";
74}
75#endif
76
77// Resolve the relocations for all symbols we currently know about.
78void RuntimeDyldImpl::resolveRelocations() {
79 MutexGuard locked(lock);
80
81 // First, resolve relocations associated with external symbols.
82 resolveExternalSymbols();
83
84 // Just iterate over the sections we have and resolve all the relocations
85 // in them. Gross overkill, but it gets the job done.
86 for (int i = 0, e = Sections.size(); i != e; ++i) {
87 // The Section here (Sections[i]) refers to the section in which the
88 // symbol for the relocation is located. The SectionID in the relocation
89 // entry provides the section to which the relocation will be applied.
90 uint64_t Addr = Sections[i].LoadAddress;
91 DEBUG(dbgs() << "Resolving relocations Section #" << i << "\t"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "Resolving relocations Section #"
<< i << "\t" << format("0x%x", Addr) <<
"\n"; } } while (0)
92 << format("0x%x", Addr) << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "Resolving relocations Section #"
<< i << "\t" << format("0x%x", Addr) <<
"\n"; } } while (0);
93 DEBUG(dumpSectionMemory(Sections[i], "before relocations"))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dumpSectionMemory(Sections[i], "before relocations"
); } } while (0);
94 resolveRelocationList(Relocations[i], Addr);
95 DEBUG(dumpSectionMemory(Sections[i], "after relocations"))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dumpSectionMemory(Sections[i], "after relocations"
); } } while (0);
96 Relocations.erase(i);
97 }
98}
99
100void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
101 uint64_t TargetAddress) {
102 MutexGuard locked(lock);
103 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
104 if (Sections[i].Address == LocalAddress) {
105 reassignSectionAddress(i, TargetAddress);
106 return;
107 }
108 }
109 llvm_unreachable("Attempting to remap address of unknown section!")::llvm::llvm_unreachable_internal("Attempting to remap address of unknown section!"
, "/tmp/buildd/llvm-toolchain-snapshot-3.6~svn216889/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp"
, 109);
110}
111
112static std::error_code getOffset(const SymbolRef &Sym, uint64_t &Result) {
113 uint64_t Address;
114 if (std::error_code EC = Sym.getAddress(Address))
115 return EC;
116
117 if (Address == UnknownAddressOrSize) {
118 Result = UnknownAddressOrSize;
119 return object_error::success;
120 }
121
122 const ObjectFile *Obj = Sym.getObject();
123 section_iterator SecI(Obj->section_begin());
124 if (std::error_code EC = Sym.getSection(SecI))
125 return EC;
126
127 if (SecI == Obj->section_end()) {
128 Result = UnknownAddressOrSize;
129 return object_error::success;
130 }
131
132 uint64_t SectionAddress;
133 if (std::error_code EC = SecI->getAddress(SectionAddress))
134 return EC;
135
136 Result = Address - SectionAddress;
137 return object_error::success;
138}
139
140ObjectImage *RuntimeDyldImpl::loadObject(ObjectImage *InputObject) {
141 MutexGuard locked(lock);
142
143 std::unique_ptr<ObjectImage> Obj(InputObject);
144 if (!Obj)
145 return nullptr;
146
147 // Save information about our target
148 Arch = (Triple::ArchType)Obj->getArch();
149 IsTargetLittleEndian = Obj->getObjectFile()->isLittleEndian();
150
151 // Compute the memory size required to load all sections to be loaded
152 // and pass this information to the memory manager
153 if (MemMgr->needsToReserveAllocationSpace()) {
154 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
155 computeTotalAllocSize(*Obj, CodeSize, DataSizeRO, DataSizeRW);
156 MemMgr->reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
157 }
158
159 // Symbols found in this object
160 StringMap<SymbolLoc> LocalSymbols;
161 // Used sections from the object file
162 ObjSectionToIDMap LocalSections;
163
164 // Common symbols requiring allocation, with their sizes and alignments
165 CommonSymbolMap CommonSymbols;
166 // Maximum required total memory to allocate all common symbols
167 uint64_t CommonSize = 0;
168
169 // Parse symbols
170 DEBUG(dbgs() << "Parse symbols:\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "Parse symbols:\n"; } } while (0);
171 for (symbol_iterator I = Obj->begin_symbols(), E = Obj->end_symbols(); I != E;
172 ++I) {
173 object::SymbolRef::Type SymType;
174 StringRef Name;
175 Check(I->getType(SymType));
176 Check(I->getName(Name));
177
178 uint32_t Flags = I->getFlags();
179
180 bool IsCommon = Flags & SymbolRef::SF_Common;
181 if (IsCommon) {
182 // Add the common symbols to a list. We'll allocate them all below.
183 if (!GlobalSymbolTable.count(Name)) {
184 uint32_t Align;
185 Check(I->getAlignment(Align));
186 uint64_t Size = 0;
187 Check(I->getSize(Size));
188 CommonSize += Size + Align;
189 CommonSymbols[*I] = CommonSymbolInfo(Size, Align);
190 }
191 } else {
192 if (SymType == object::SymbolRef::ST_Function ||
193 SymType == object::SymbolRef::ST_Data ||
194 SymType == object::SymbolRef::ST_Unknown) {
195 uint64_t SectOffset;
196 StringRef SectionData;
197 bool IsCode;
198 section_iterator SI = Obj->end_sections();
199 Check(getOffset(*I, SectOffset));
200 Check(I->getSection(SI));
201 if (SI == Obj->end_sections())
202 continue;
203 Check(SI->getContents(SectionData));
204 Check(SI->isText(IsCode));
205 unsigned SectionID =
206 findOrEmitSection(*Obj, *SI, IsCode, LocalSections);
207 LocalSymbols[Name.data()] = SymbolLoc(SectionID, SectOffset);
208 DEBUG(dbgs() << "\tOffset: " << format("%p", (uintptr_t)SectOffset)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "\tOffset: " << format("%p"
, (uintptr_t)SectOffset) << " flags: " << Flags <<
" SID: " << SectionID; } } while (0)
209 << " flags: " << Flags << " SID: " << SectionID)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "\tOffset: " << format("%p"
, (uintptr_t)SectOffset) << " flags: " << Flags <<
" SID: " << SectionID; } } while (0);
210 GlobalSymbolTable[Name] = SymbolLoc(SectionID, SectOffset);
211 }
212 }
213 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "\tType: " << SymType <<
" Name: " << Name << "\n"; } } while (0);
214 }
215
216 // Allocate common symbols
217 if (CommonSize != 0)
218 emitCommonSymbols(*Obj, CommonSymbols, CommonSize, GlobalSymbolTable);
219
220 // Parse and process relocations
221 DEBUG(dbgs() << "Parse relocations:\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "Parse relocations:\n"; } } while
(0);
222 for (section_iterator SI = Obj->begin_sections(), SE = Obj->end_sections();
223 SI != SE; ++SI) {
224 unsigned SectionID = 0;
225 StubMap Stubs;
226 section_iterator RelocatedSection = SI->getRelocatedSection();
227
228 relocation_iterator I = SI->relocation_begin();
229 relocation_iterator E = SI->relocation_end();
230
231 if (I == E && !ProcessAllSections)
232 continue;
233
234 bool IsCode = false;
235 Check(RelocatedSection->isText(IsCode));
236 SectionID =
237 findOrEmitSection(*Obj, *RelocatedSection, IsCode, LocalSections);
238 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "\tSectionID: " << SectionID
<< "\n"; } } while (0);
239
240 for (; I != E;)
241 I = processRelocationRef(SectionID, I, *Obj, LocalSections, LocalSymbols,
242 Stubs);
243
244 // If there is an attached checker, notify it about the stubs for this
245 // section so that they can be verified.
246 if (Checker)
247 Checker->registerStubMap(Obj->getImageName(), SectionID, Stubs);
248 }
249
250 // Give the subclasses a chance to tie-up any loose ends.
251 finalizeLoad(*Obj, LocalSections);
252
253 return Obj.release();
254}
255
256// A helper method for computeTotalAllocSize.
257// Computes the memory size required to allocate sections with the given sizes,
258// assuming that all sections are allocated with the given alignment
259static uint64_t
260computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
261 uint64_t Alignment) {
262 uint64_t TotalSize = 0;
263 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
264 uint64_t AlignedSize =
265 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
266 TotalSize += AlignedSize;
267 }
268 return TotalSize;
269}
270
271// Compute an upper bound of the memory size that is required to load all
272// sections
273void RuntimeDyldImpl::computeTotalAllocSize(ObjectImage &Obj,
274 uint64_t &CodeSize,
275 uint64_t &DataSizeRO,
276 uint64_t &DataSizeRW) {
277 // Compute the size of all sections required for execution
278 std::vector<uint64_t> CodeSectionSizes;
279 std::vector<uint64_t> ROSectionSizes;
280 std::vector<uint64_t> RWSectionSizes;
281 uint64_t MaxAlignment = sizeof(void *);
282
283 // Collect sizes of all sections to be loaded;
284 // also determine the max alignment of all sections
285 for (section_iterator SI = Obj.begin_sections(), SE = Obj.end_sections();
286 SI != SE; ++SI) {
287 const SectionRef &Section = *SI;
288
289 bool IsRequired;
290 Check(Section.isRequiredForExecution(IsRequired));
291
292 // Consider only the sections that are required to be loaded for execution
293 if (IsRequired) {
294 uint64_t DataSize = 0;
295 uint64_t Alignment64 = 0;
296 bool IsCode = false;
297 bool IsReadOnly = false;
298 StringRef Name;
299 Check(Section.getSize(DataSize));
300 Check(Section.getAlignment(Alignment64));
301 Check(Section.isText(IsCode));
302 Check(Section.isReadOnlyData(IsReadOnly));
303 Check(Section.getName(Name));
304 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
305
306 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
307 uint64_t SectionSize = DataSize + StubBufSize;
308
309 // The .eh_frame section (at least on Linux) needs an extra four bytes
310 // padded
311 // with zeroes added at the end. For MachO objects, this section has a
312 // slightly different name, so this won't have any effect for MachO
313 // objects.
314 if (Name == ".eh_frame")
315 SectionSize += 4;
316
317 if (SectionSize > 0) {
318 // save the total size of the section
319 if (IsCode) {
320 CodeSectionSizes.push_back(SectionSize);
321 } else if (IsReadOnly) {
322 ROSectionSizes.push_back(SectionSize);
323 } else {
324 RWSectionSizes.push_back(SectionSize);
325 }
326 // update the max alignment
327 if (Alignment > MaxAlignment) {
328 MaxAlignment = Alignment;
329 }
330 }
331 }
332 }
333
334 // Compute the size of all common symbols
335 uint64_t CommonSize = 0;
336 for (symbol_iterator I = Obj.begin_symbols(), E = Obj.end_symbols(); I != E;
337 ++I) {
338 uint32_t Flags = I->getFlags();
339 if (Flags & SymbolRef::SF_Common) {
340 // Add the common symbols to a list. We'll allocate them all below.
341 uint64_t Size = 0;
342 Check(I->getSize(Size));
343 CommonSize += Size;
344 }
345 }
346 if (CommonSize != 0) {
347 RWSectionSizes.push_back(CommonSize);
348 }
349
350 // Compute the required allocation space for each different type of sections
351 // (code, read-only data, read-write data) assuming that all sections are
352 // allocated with the max alignment. Note that we cannot compute with the
353 // individual alignments of the sections, because then the required size
354 // depends on the order, in which the sections are allocated.
355 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
356 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
357 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
358}
359
360// compute stub buffer size for the given section
361unsigned RuntimeDyldImpl::computeSectionStubBufSize(ObjectImage &Obj,
362 const SectionRef &Section) {
363 unsigned StubSize = getMaxStubSize();
364 if (StubSize == 0) {
365 return 0;
366 }
367 // FIXME: this is an inefficient way to handle this. We should computed the
368 // necessary section allocation size in loadObject by walking all the sections
369 // once.
370 unsigned StubBufSize = 0;
371 for (section_iterator SI = Obj.begin_sections(), SE = Obj.end_sections();
372 SI != SE; ++SI) {
373 section_iterator RelSecI = SI->getRelocatedSection();
374 if (!(RelSecI == Section))
375 continue;
376
377 for (const RelocationRef &Reloc : SI->relocations()) {
378 (void)Reloc;
379 StubBufSize += StubSize;
380 }
381 }
382
383 // Get section data size and alignment
384 uint64_t Alignment64;
385 uint64_t DataSize;
386 Check(Section.getSize(DataSize));
387 Check(Section.getAlignment(Alignment64));
388
389 // Add stubbuf size alignment
390 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
391 unsigned StubAlignment = getStubAlignment();
392 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
393 if (StubAlignment > EndAlignment)
394 StubBufSize += StubAlignment - EndAlignment;
395 return StubBufSize;
396}
397
398uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
399 unsigned Size) const {
400 uint64_t Result = 0;
401 uint8_t *Dst = reinterpret_cast<uint8_t*>(&Result);
402
403 if (IsTargetLittleEndian == sys::IsLittleEndianHost) {
1
Taking false branch
→
404 if (!sys::IsLittleEndianHost)
405 Dst += sizeof(Result) - Size;
406 memcpy(Dst, Src, Size);
407 } else {
408 Dst += Size - 1;
409 for (unsigned i = 0; i < Size; ++i)
2
←
Assuming 'i' is < 'Size'
→
3
←
Loop condition is true. Entering loop body
→
5
←
Assuming 'i' is >= 'Size'
→
6
←
Loop condition is false. Execution continues on line 413
→
410 *Dst-- = *Src++;
4
←
Uninitialized value stored to 'Result'
→
411 }
412
413 return Result;
7
←
Undefined or garbage value returned to caller
414}
415
416void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
417 unsigned Size) const {
418 uint8_t *Src = reinterpret_cast<uint8_t*>(&Value);
419 if (IsTargetLittleEndian == sys::IsLittleEndianHost) {
420 if (!sys::IsLittleEndianHost)
421 Src += sizeof(Value) - Size;
422 memcpy(Dst, Src, Size);
423 } else {
424 Src += Size - 1;
425 for (unsigned i = 0; i < Size; ++i)
426 *Dst++ = *Src--;
427 }
428}
429
430void RuntimeDyldImpl::emitCommonSymbols(ObjectImage &Obj,
431 const CommonSymbolMap &CommonSymbols,
432 uint64_t TotalSize,
433 SymbolTableMap &SymbolTable) {
434 // Allocate memory for the section
435 unsigned SectionID = Sections.size();
436 uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, sizeof(void *),
437 SectionID, StringRef(), false);
438 if (!Addr)
439 report_fatal_error("Unable to allocate memory for common symbols!");
440 uint64_t Offset = 0;
441 Sections.push_back(SectionEntry("<common symbols>", Addr, TotalSize, 0));
442 memset(Addr, 0, TotalSize);
443
444 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "emitCommonSection SectionID: " <<
SectionID << " new addr: " << format("%p", Addr)
<< " DataSize: " << TotalSize << "\n"; } }
while (0)
445 << format("%p", Addr) << " DataSize: " << TotalSize << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "emitCommonSection SectionID: " <<
SectionID << " new addr: " << format("%p", Addr)
<< " DataSize: " << TotalSize << "\n"; } }
while (0);
446
447 // Assign the address of each symbol
448 for (CommonSymbolMap::const_iterator it = CommonSymbols.begin(),
449 itEnd = CommonSymbols.end(); it != itEnd; ++it) {
450 uint64_t Size = it->second.first;
451 uint64_t Align = it->second.second;
452 StringRef Name;
453 it->first.getName(Name);
454 if (Align) {
455 // This symbol has an alignment requirement.
456 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
457 Addr += AlignOffset;
458 Offset += AlignOffset;
459 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "Allocating common symbol " <<
Name << " address " << format("%p\n", Addr); } }
while (0)
460 << format("%p\n", Addr))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "Allocating common symbol " <<
Name << " address " << format("%p\n", Addr); } }
while (0);
461 }
462 Obj.updateSymbolAddress(it->first, (uint64_t)Addr);
463 SymbolTable[Name.data()] = SymbolLoc(SectionID, Offset);
464 Offset += Size;
465 Addr += Size;
466 }
467}
468
469unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
470 const SectionRef &Section, bool IsCode) {
471
472 StringRef data;
473 uint64_t Alignment64;
474 Check(Section.getContents(data));
475 Check(Section.getAlignment(Alignment64));
476
477 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
478 bool IsRequired;
479 bool IsVirtual;
480 bool IsZeroInit;
481 bool IsReadOnly;
482 uint64_t DataSize;
483 unsigned PaddingSize = 0;
484 unsigned StubBufSize = 0;
485 StringRef Name;
486 Check(Section.isRequiredForExecution(IsRequired));
487 Check(Section.isVirtual(IsVirtual));
488 Check(Section.isZeroInit(IsZeroInit));
489 Check(Section.isReadOnlyData(IsReadOnly));
490 Check(Section.getSize(DataSize));
491 Check(Section.getName(Name));
492
493 StubBufSize = computeSectionStubBufSize(Obj, Section);
494
495 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
496 // with zeroes added at the end. For MachO objects, this section has a
497 // slightly different name, so this won't have any effect for MachO objects.
498 if (Name == ".eh_frame")
499 PaddingSize = 4;
500
501 uintptr_t Allocate;
502 unsigned SectionID = Sections.size();
503 uint8_t *Addr;
504 const char *pData = nullptr;
505
506 // Some sections, such as debug info, don't need to be loaded for execution.
507 // Leave those where they are.
508 if (IsRequired) {
509 Allocate = DataSize + PaddingSize + StubBufSize;
510 Addr = IsCode ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID,
511 Name)
512 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID,
513 Name, IsReadOnly);
514 if (!Addr)
515 report_fatal_error("Unable to allocate section memory!");
516
517 // Virtual sections have no data in the object image, so leave pData = 0
518 if (!IsVirtual)
519 pData = data.data();
520
521 // Zero-initialize or copy the data from the image
522 if (IsZeroInit || IsVirtual)
523 memset(Addr, 0, DataSize);
524 else
525 memcpy(Addr, pData, DataSize);
526
527 // Fill in any extra bytes we allocated for padding
528 if (PaddingSize != 0) {
529 memset(Addr + DataSize, 0, PaddingSize);
530 // Update the DataSize variable so that the stub offset is set correctly.
531 DataSize += PaddingSize;
532 }
533
534 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Namedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "emitSection SectionID: " <<
SectionID << " Name: " << Name << " obj addr: "
<< format("%p", pData) << " new addr: " <<
format("%p", Addr) << " DataSize: " << DataSize <<
" StubBufSize: " << StubBufSize << " Allocate: "
<< Allocate << "\n"; } } while (0)
535 << " obj addr: " << format("%p", pData)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "emitSection SectionID: " <<
SectionID << " Name: " << Name << " obj addr: "
<< format("%p", pData) << " new addr: " <<
format("%p", Addr) << " DataSize: " << DataSize <<
" StubBufSize: " << StubBufSize << " Allocate: "
<< Allocate << "\n"; } } while (0)
536 << " new addr: " << format("%p", Addr)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "emitSection SectionID: " <<
SectionID << " Name: " << Name << " obj addr: "
<< format("%p", pData) << " new addr: " <<
format("%p", Addr) << " DataSize: " << DataSize <<
" StubBufSize: " << StubBufSize << " Allocate: "
<< Allocate << "\n"; } } while (0)
537 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSizedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "emitSection SectionID: " <<
SectionID << " Name: " << Name << " obj addr: "
<< format("%p", pData) << " new addr: " <<
format("%p", Addr) << " DataSize: " << DataSize <<
" StubBufSize: " << StubBufSize << " Allocate: "
<< Allocate << "\n"; } } while (0)
538 << " Allocate: " << Allocate << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "emitSection SectionID: " <<
SectionID << " Name: " << Name << " obj addr: "
<< format("%p", pData) << " new addr: " <<
format("%p", Addr) << " DataSize: " << DataSize <<
" StubBufSize: " << StubBufSize << " Allocate: "
<< Allocate << "\n"; } } while (0);
539 Obj.updateSectionAddress(Section, (uint64_t)Addr);
540 } else {
541 // Even if we didn't load the section, we need to record an entry for it
542 // to handle later processing (and by 'handle' I mean don't do anything
543 // with these sections).
544 Allocate = 0;
545 Addr = nullptr;
546 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Namedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "emitSection SectionID: " <<
SectionID << " Name: " << Name << " obj addr: "
<< format("%p", data.data()) << " new addr: 0" <<
" DataSize: " << DataSize << " StubBufSize: " <<
StubBufSize << " Allocate: " << Allocate <<
"\n"; } } while (0)
547 << " obj addr: " << format("%p", data.data()) << " new addr: 0"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "emitSection SectionID: " <<
SectionID << " Name: " << Name << " obj addr: "
<< format("%p", data.data()) << " new addr: 0" <<
" DataSize: " << DataSize << " StubBufSize: " <<
StubBufSize << " Allocate: " << Allocate <<
"\n"; } } while (0)
548 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSizedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "emitSection SectionID: " <<
SectionID << " Name: " << Name << " obj addr: "
<< format("%p", data.data()) << " new addr: 0" <<
" DataSize: " << DataSize << " StubBufSize: " <<
StubBufSize << " Allocate: " << Allocate <<
"\n"; } } while (0)
549 << " Allocate: " << Allocate << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "emitSection SectionID: " <<
SectionID << " Name: " << Name << " obj addr: "
<< format("%p", data.data()) << " new addr: 0" <<
" DataSize: " << DataSize << " StubBufSize: " <<
StubBufSize << " Allocate: " << Allocate <<
"\n"; } } while (0);
550 }
551
552 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
553 return SectionID;
554}
555
556unsigned RuntimeDyldImpl::findOrEmitSection(ObjectImage &Obj,
557 const SectionRef &Section,
558 bool IsCode,
559 ObjSectionToIDMap &LocalSections) {
560
561 unsigned SectionID = 0;
562 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
563 if (i != LocalSections.end())
564 SectionID = i->second;
565 else {
566 SectionID = emitSection(Obj, Section, IsCode);
567 LocalSections[Section] = SectionID;
568 }
569 return SectionID;
570}
571
572void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
573 unsigned SectionID) {
574 Relocations[SectionID].push_back(RE);
575}
576
577void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
578 StringRef SymbolName) {
579 // Relocation by symbol. If the symbol is found in the global symbol table,
580 // create an appropriate section relocation. Otherwise, add it to
581 // ExternalSymbolRelocations.
582 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
583 if (Loc == GlobalSymbolTable.end()) {
584 ExternalSymbolRelocations[SymbolName].push_back(RE);
585 } else {
586 // Copy the RE since we want to modify its addend.
587 RelocationEntry RECopy = RE;
588 RECopy.Addend += Loc->second.second;
589 Relocations[Loc->second.first].push_back(RECopy);
590 }
591}
592
593uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
594 unsigned AbiVariant) {
595 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
596 // This stub has to be able to access the full address space,
597 // since symbol lookup won't necessarily find a handy, in-range,
598 // PLT stub for functions which could be anywhere.
599 uint32_t *StubAddr = (uint32_t *)Addr;
600
601 // Stub can use ip0 (== x16) to calculate address
602 *StubAddr = 0xd2e00010; // movz ip0, #:abs_g3:<addr>
603 StubAddr++;
604 *StubAddr = 0xf2c00010; // movk ip0, #:abs_g2_nc:<addr>
605 StubAddr++;
606 *StubAddr = 0xf2a00010; // movk ip0, #:abs_g1_nc:<addr>
607 StubAddr++;
608 *StubAddr = 0xf2800010; // movk ip0, #:abs_g0_nc:<addr>
609 StubAddr++;
610 *StubAddr = 0xd61f0200; // br ip0
611
612 return Addr;
613 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
614 // TODO: There is only ARM far stub now. We should add the Thumb stub,
615 // and stubs for branches Thumb - ARM and ARM - Thumb.
616 uint32_t *StubAddr = (uint32_t *)Addr;
617 *StubAddr = 0xe51ff004; // ldr pc,<label>
618 return (uint8_t *)++StubAddr;
619 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
620 uint32_t *StubAddr = (uint32_t *)Addr;
621 // 0: 3c190000 lui t9,%hi(addr).
622 // 4: 27390000 addiu t9,t9,%lo(addr).
623 // 8: 03200008 jr t9.
624 // c: 00000000 nop.
625 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
626 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
627
628 *StubAddr = LuiT9Instr;
629 StubAddr++;
630 *StubAddr = AdduiT9Instr;
631 StubAddr++;
632 *StubAddr = JrT9Instr;
633 StubAddr++;
634 *StubAddr = NopInstr;
635 return Addr;
636 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
637 // Depending on which version of the ELF ABI is in use, we need to
638 // generate one of two variants of the stub. They both start with
639 // the same sequence to load the target address into r12.
640 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
641 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
642 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
643 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
644 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
645 if (AbiVariant == 2) {
646 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
647 // The address is already in r12 as required by the ABI. Branch to it.
648 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
649 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
650 writeInt32BE(Addr+28, 0x4E800420); // bctr
651 } else {
652 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
653 // Load the function address on r11 and sets it to control register. Also
654 // loads the function TOC in r2 and environment pointer to r11.
655 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
656 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
657 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
658 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
659 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
660 writeInt32BE(Addr+40, 0x4E800420); // bctr
661 }
662 return Addr;
663 } else if (Arch == Triple::systemz) {
664 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
665 writeInt16BE(Addr+2, 0x0000);
666 writeInt16BE(Addr+4, 0x0004);
667 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
668 // 8-byte address stored at Addr + 8
669 return Addr;
670 } else if (Arch == Triple::x86_64) {
671 *Addr = 0xFF; // jmp
672 *(Addr+1) = 0x25; // rip
673 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
674 } else if (Arch == Triple::x86) {
675 *Addr = 0xE9; // 32-bit pc-relative jump.
676 }
677 return Addr;
678}
679
680// Assign an address to a symbol name and resolve all the relocations
681// associated with it.
682void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
683 uint64_t Addr) {
684 // The address to use for relocation resolution is not
685 // the address of the local section buffer. We must be doing
686 // a remote execution environment of some sort. Relocations can't
687 // be applied until all the sections have been moved. The client must
688 // trigger this with a call to MCJIT::finalize() or
689 // RuntimeDyld::resolveRelocations().
690 //
691 // Addr is a uint64_t because we can't assume the pointer width
692 // of the target is the same as that of the host. Just use a generic
693 // "big enough" type.
694 Sections[SectionID].LoadAddress = Addr;
695}
696
697void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
698 uint64_t Value) {
699 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
700 const RelocationEntry &RE = Relocs[i];
701 // Ignore relocations for sections that were not loaded
702 if (Sections[RE.SectionID].Address == nullptr)
703 continue;
704 resolveRelocation(RE, Value);
705 }
706}
707
708void RuntimeDyldImpl::resolveExternalSymbols() {
709 while (!ExternalSymbolRelocations.empty()) {
710 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
711
712 StringRef Name = i->first();
713 if (Name.size() == 0) {
714 // This is an absolute symbol, use an address of zero.
715 DEBUG(dbgs() << "Resolving absolute relocations."do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "Resolving absolute relocations."
<< "\n"; } } while (0)
716 << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "Resolving absolute relocations."
<< "\n"; } } while (0);
717 RelocationList &Relocs = i->second;
718 resolveRelocationList(Relocs, 0);
719 } else {
720 uint64_t Addr = 0;
721 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(Name);
722 if (Loc == GlobalSymbolTable.end()) {
723 // This is an external symbol, try to get its address from
724 // MemoryManager.
725 Addr = MemMgr->getSymbolAddress(Name.data());
726 // The call to getSymbolAddress may have caused additional modules to
727 // be loaded, which may have added new entries to the
728 // ExternalSymbolRelocations map. Consquently, we need to update our
729 // iterator. This is also why retrieval of the relocation list
730 // associated with this symbol is deferred until below this point.
731 // New entries may have been added to the relocation list.
732 i = ExternalSymbolRelocations.find(Name);
733 } else {
734 // We found the symbol in our global table. It was probably in a
735 // Module that we loaded previously.
736 SymbolLoc SymLoc = Loc->second;
737 Addr = getSectionLoadAddress(SymLoc.first) + SymLoc.second;
738 }
739
740 // FIXME: Implement error handling that doesn't kill the host program!
741 if (!Addr)
742 report_fatal_error("Program used external function '" + Name +
743 "' which could not be resolved!");
744
745 updateGOTEntries(Name, Addr);
746 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "Resolving relocations Name: " <<
Name << "\t" << format("0x%lx", Addr) << "\n"
; } } while (0)
747 << format("0x%lx", Addr) << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("dyld")) { dbgs() << "Resolving relocations Name: " <<
Name << "\t" << format("0x%lx", Addr) << "\n"
; } } while (0);
748 // This list may have been updated when we called getSymbolAddress, so
749 // don't change this code to get the list earlier.
750 RelocationList &Relocs = i->second;
751 resolveRelocationList(Relocs, Addr);
752 }
753
754 ExternalSymbolRelocations.erase(i);
755 }
756}
757
758//===----------------------------------------------------------------------===//
759// RuntimeDyld class implementation
760RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
761 // FIXME: There's a potential issue lurking here if a single instance of
762 // RuntimeDyld is used to load multiple objects. The current implementation
763 // associates a single memory manager with a RuntimeDyld instance. Even
764 // though the public class spawns a new 'impl' instance for each load,
765 // they share a single memory manager. This can become a problem when page
766 // permissions are applied.
767 Dyld = nullptr;
768 MM = mm;
769 ProcessAllSections = false;
770 Checker = nullptr;
771}
772
773RuntimeDyld::~RuntimeDyld() { delete Dyld; }
774
775static std::unique_ptr<RuntimeDyldELF>
776createRuntimeDyldELF(RTDyldMemoryManager *MM, bool ProcessAllSections,
777 RuntimeDyldCheckerImpl *Checker) {
778 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM));
779 Dyld->setProcessAllSections(ProcessAllSections);
780 Dyld->setRuntimeDyldChecker(Checker);
781 return Dyld;
782}
783
784static std::unique_ptr<RuntimeDyldMachO>
785createRuntimeDyldMachO(Triple::ArchType Arch, RTDyldMemoryManager *MM,
786 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
787 std::unique_ptr<RuntimeDyldMachO> Dyld(RuntimeDyldMachO::create(Arch, MM));
788 Dyld->setProcessAllSections(ProcessAllSections);
789 Dyld->setRuntimeDyldChecker(Checker);
790 return Dyld;
791}
792
793ObjectImage *RuntimeDyld::loadObject(std::unique_ptr<ObjectFile> InputObject) {
794 std::unique_ptr<ObjectImage> InputImage;
795
796 ObjectFile &Obj = *InputObject;
797
798 if (InputObject->isELF()) {
799 InputImage.reset(RuntimeDyldELF::createObjectImageFromFile(std::move(InputObject)));
800 if (!Dyld)
801 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker).release();
802 } else if (InputObject->isMachO()) {
803 InputImage.reset(RuntimeDyldMachO::createObjectImageFromFile(std::move(InputObject)));
804 if (!Dyld)
805 Dyld = createRuntimeDyldMachO(
806 static_cast<Triple::ArchType>(InputImage->getArch()),
807 MM, ProcessAllSections, Checker).release();
808 } else
809 report_fatal_error("Incompatible object format!");
810
811 if (!Dyld->isCompatibleFile(&Obj))
812 report_fatal_error("Incompatible object format!");
813
814 Dyld->loadObject(InputImage.get());
815 return InputImage.release();
816}
817
818ObjectImage *RuntimeDyld::loadObject(ObjectBuffer *InputBuffer) {
819 std::unique_ptr<ObjectImage> InputImage;
820 sys::fs::file_magic Type = sys::fs::identify_magic(InputBuffer->getBuffer());
821
822 switch (Type) {
823 case sys::fs::file_magic::elf_relocatable:
824 case sys::fs::file_magic::elf_executable:
825 case sys::fs::file_magic::elf_shared_object:
826 case sys::fs::file_magic::elf_core:
827 InputImage.reset(RuntimeDyldELF::createObjectImage(InputBuffer));
828 if (!Dyld)
829 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker).release();
830 break;
831 case sys::fs::file_magic::macho_object:
832 case sys::fs::file_magic::macho_executable:
833 case sys::fs::file_magic::macho_fixed_virtual_memory_shared_lib:
834 case sys::fs::file_magic::macho_core:
835 case sys::fs::file_magic::macho_preload_executable:
836 case sys::fs::file_magic::macho_dynamically_linked_shared_lib:
837 case sys::fs::file_magic::macho_dynamic_linker:
838 case sys::fs::file_magic::macho_bundle:
839 case sys::fs::file_magic::macho_dynamically_linked_shared_lib_stub:
840 case sys::fs::file_magic::macho_dsym_companion:
841 InputImage.reset(RuntimeDyldMachO::createObjectImage(InputBuffer));
842 if (!Dyld)
843 Dyld = createRuntimeDyldMachO(
844 static_cast<Triple::ArchType>(InputImage->getArch()),
845 MM, ProcessAllSections, Checker).release();
846 break;
847 case sys::fs::file_magic::unknown:
848 case sys::fs::file_magic::bitcode:
849 case sys::fs::file_magic::archive:
850 case sys::fs::file_magic::coff_object:
851 case sys::fs::file_magic::coff_import_library:
852 case sys::fs::file_magic::pecoff_executable:
853 case sys::fs::file_magic::macho_universal_binary:
854 case sys::fs::file_magic::windows_resource:
855 report_fatal_error("Incompatible object format!");
856 }
857
858 if (!Dyld->isCompatibleFormat(InputBuffer))
859 report_fatal_error("Incompatible object format!");
860
861 Dyld->loadObject(InputImage.get());
862 return InputImage.release();
863}
864
865void *RuntimeDyld::getSymbolAddress(StringRef Name) {
866 if (!Dyld)
867 return nullptr;
868 return Dyld->getSymbolAddress(Name);
869}
870
871uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) {
872 if (!Dyld)
873 return 0;
874 return Dyld->getSymbolLoadAddress(Name);
875}
876
877void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
878
879void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
880 Dyld->reassignSectionAddress(SectionID, Addr);
881}
882
883void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
884 uint64_t TargetAddress) {
885 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
886}
887
888bool RuntimeDyld::hasError() { return Dyld->hasError(); }
889
890StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
891
892void RuntimeDyld::registerEHFrames() {
893 if (Dyld)
894 Dyld->registerEHFrames();
895}
896
897void RuntimeDyld::deregisterEHFrames() {
898 if (Dyld)
899 Dyld->deregisterEHFrames();
900}
901
902} // end namespace llvm