xref: /freebsd/contrib/llvm-project/llvm/lib/Object/ELF.cpp (revision e6bfd18d21b225af6a0ed67ceeaf1293b7b9eba5)
1 //===- ELF.cpp - ELF object file implementation ---------------------------===//
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 #include "llvm/Object/ELF.h"
10 #include "llvm/BinaryFormat/ELF.h"
11 #include "llvm/Support/DataExtractor.h"
12 
13 using namespace llvm;
14 using namespace object;
15 
16 #define STRINGIFY_ENUM_CASE(ns, name)                                          \
17   case ns::name:                                                               \
18     return #name;
19 
20 #define ELF_RELOC(name, value) STRINGIFY_ENUM_CASE(ELF, name)
21 
22 StringRef llvm::object::getELFRelocationTypeName(uint32_t Machine,
23                                                  uint32_t Type) {
24   switch (Machine) {
25   case ELF::EM_68K:
26     switch (Type) {
27 #include "llvm/BinaryFormat/ELFRelocs/M68k.def"
28     default:
29       break;
30     }
31     break;
32   case ELF::EM_X86_64:
33     switch (Type) {
34 #include "llvm/BinaryFormat/ELFRelocs/x86_64.def"
35     default:
36       break;
37     }
38     break;
39   case ELF::EM_386:
40   case ELF::EM_IAMCU:
41     switch (Type) {
42 #include "llvm/BinaryFormat/ELFRelocs/i386.def"
43     default:
44       break;
45     }
46     break;
47   case ELF::EM_MIPS:
48     switch (Type) {
49 #include "llvm/BinaryFormat/ELFRelocs/Mips.def"
50     default:
51       break;
52     }
53     break;
54   case ELF::EM_AARCH64:
55     switch (Type) {
56 #include "llvm/BinaryFormat/ELFRelocs/AArch64.def"
57     default:
58       break;
59     }
60     break;
61   case ELF::EM_ARM:
62     switch (Type) {
63 #include "llvm/BinaryFormat/ELFRelocs/ARM.def"
64     default:
65       break;
66     }
67     break;
68   case ELF::EM_ARC_COMPACT:
69   case ELF::EM_ARC_COMPACT2:
70     switch (Type) {
71 #include "llvm/BinaryFormat/ELFRelocs/ARC.def"
72     default:
73       break;
74     }
75     break;
76   case ELF::EM_AVR:
77     switch (Type) {
78 #include "llvm/BinaryFormat/ELFRelocs/AVR.def"
79     default:
80       break;
81     }
82     break;
83   case ELF::EM_HEXAGON:
84     switch (Type) {
85 #include "llvm/BinaryFormat/ELFRelocs/Hexagon.def"
86     default:
87       break;
88     }
89     break;
90   case ELF::EM_LANAI:
91     switch (Type) {
92 #include "llvm/BinaryFormat/ELFRelocs/Lanai.def"
93     default:
94       break;
95     }
96     break;
97   case ELF::EM_PPC:
98     switch (Type) {
99 #include "llvm/BinaryFormat/ELFRelocs/PowerPC.def"
100     default:
101       break;
102     }
103     break;
104   case ELF::EM_PPC64:
105     switch (Type) {
106 #include "llvm/BinaryFormat/ELFRelocs/PowerPC64.def"
107     default:
108       break;
109     }
110     break;
111   case ELF::EM_RISCV:
112     switch (Type) {
113 #include "llvm/BinaryFormat/ELFRelocs/RISCV.def"
114     default:
115       break;
116     }
117     break;
118   case ELF::EM_S390:
119     switch (Type) {
120 #include "llvm/BinaryFormat/ELFRelocs/SystemZ.def"
121     default:
122       break;
123     }
124     break;
125   case ELF::EM_SPARC:
126   case ELF::EM_SPARC32PLUS:
127   case ELF::EM_SPARCV9:
128     switch (Type) {
129 #include "llvm/BinaryFormat/ELFRelocs/Sparc.def"
130     default:
131       break;
132     }
133     break;
134   case ELF::EM_AMDGPU:
135     switch (Type) {
136 #include "llvm/BinaryFormat/ELFRelocs/AMDGPU.def"
137     default:
138       break;
139     }
140     break;
141   case ELF::EM_BPF:
142     switch (Type) {
143 #include "llvm/BinaryFormat/ELFRelocs/BPF.def"
144     default:
145       break;
146     }
147     break;
148   case ELF::EM_MSP430:
149     switch (Type) {
150 #include "llvm/BinaryFormat/ELFRelocs/MSP430.def"
151     default:
152       break;
153     }
154     break;
155   case ELF::EM_VE:
156     switch (Type) {
157 #include "llvm/BinaryFormat/ELFRelocs/VE.def"
158     default:
159       break;
160     }
161     break;
162   case ELF::EM_CSKY:
163     switch (Type) {
164 #include "llvm/BinaryFormat/ELFRelocs/CSKY.def"
165     default:
166       break;
167     }
168     break;
169   case ELF::EM_LOONGARCH:
170     switch (Type) {
171 #include "llvm/BinaryFormat/ELFRelocs/LoongArch.def"
172     default:
173       break;
174     }
175     break;
176   default:
177     break;
178   }
179   return "Unknown";
180 }
181 
182 #undef ELF_RELOC
183 
184 uint32_t llvm::object::getELFRelativeRelocationType(uint32_t Machine) {
185   switch (Machine) {
186   case ELF::EM_X86_64:
187     return ELF::R_X86_64_RELATIVE;
188   case ELF::EM_386:
189   case ELF::EM_IAMCU:
190     return ELF::R_386_RELATIVE;
191   case ELF::EM_MIPS:
192     break;
193   case ELF::EM_AARCH64:
194     return ELF::R_AARCH64_RELATIVE;
195   case ELF::EM_ARM:
196     return ELF::R_ARM_RELATIVE;
197   case ELF::EM_ARC_COMPACT:
198   case ELF::EM_ARC_COMPACT2:
199     return ELF::R_ARC_RELATIVE;
200   case ELF::EM_AVR:
201     break;
202   case ELF::EM_HEXAGON:
203     return ELF::R_HEX_RELATIVE;
204   case ELF::EM_LANAI:
205     break;
206   case ELF::EM_PPC:
207     break;
208   case ELF::EM_PPC64:
209     return ELF::R_PPC64_RELATIVE;
210   case ELF::EM_RISCV:
211     return ELF::R_RISCV_RELATIVE;
212   case ELF::EM_S390:
213     return ELF::R_390_RELATIVE;
214   case ELF::EM_SPARC:
215   case ELF::EM_SPARC32PLUS:
216   case ELF::EM_SPARCV9:
217     return ELF::R_SPARC_RELATIVE;
218   case ELF::EM_CSKY:
219     return ELF::R_CKCORE_RELATIVE;
220   case ELF::EM_VE:
221     return ELF::R_VE_RELATIVE;
222   case ELF::EM_AMDGPU:
223     break;
224   case ELF::EM_BPF:
225     break;
226   default:
227     break;
228   }
229   return 0;
230 }
231 
232 StringRef llvm::object::getELFSectionTypeName(uint32_t Machine, unsigned Type) {
233   switch (Machine) {
234   case ELF::EM_ARM:
235     switch (Type) {
236       STRINGIFY_ENUM_CASE(ELF, SHT_ARM_EXIDX);
237       STRINGIFY_ENUM_CASE(ELF, SHT_ARM_PREEMPTMAP);
238       STRINGIFY_ENUM_CASE(ELF, SHT_ARM_ATTRIBUTES);
239       STRINGIFY_ENUM_CASE(ELF, SHT_ARM_DEBUGOVERLAY);
240       STRINGIFY_ENUM_CASE(ELF, SHT_ARM_OVERLAYSECTION);
241     }
242     break;
243   case ELF::EM_HEXAGON:
244     switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_HEX_ORDERED); }
245     break;
246   case ELF::EM_X86_64:
247     switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_X86_64_UNWIND); }
248     break;
249   case ELF::EM_MIPS:
250   case ELF::EM_MIPS_RS3_LE:
251     switch (Type) {
252       STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_REGINFO);
253       STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_OPTIONS);
254       STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_DWARF);
255       STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_ABIFLAGS);
256     }
257     break;
258   case ELF::EM_MSP430:
259     switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_MSP430_ATTRIBUTES); }
260     break;
261   case ELF::EM_RISCV:
262     switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_RISCV_ATTRIBUTES); }
263     break;
264   default:
265     break;
266   }
267 
268   switch (Type) {
269     STRINGIFY_ENUM_CASE(ELF, SHT_NULL);
270     STRINGIFY_ENUM_CASE(ELF, SHT_PROGBITS);
271     STRINGIFY_ENUM_CASE(ELF, SHT_SYMTAB);
272     STRINGIFY_ENUM_CASE(ELF, SHT_STRTAB);
273     STRINGIFY_ENUM_CASE(ELF, SHT_RELA);
274     STRINGIFY_ENUM_CASE(ELF, SHT_HASH);
275     STRINGIFY_ENUM_CASE(ELF, SHT_DYNAMIC);
276     STRINGIFY_ENUM_CASE(ELF, SHT_NOTE);
277     STRINGIFY_ENUM_CASE(ELF, SHT_NOBITS);
278     STRINGIFY_ENUM_CASE(ELF, SHT_REL);
279     STRINGIFY_ENUM_CASE(ELF, SHT_SHLIB);
280     STRINGIFY_ENUM_CASE(ELF, SHT_DYNSYM);
281     STRINGIFY_ENUM_CASE(ELF, SHT_INIT_ARRAY);
282     STRINGIFY_ENUM_CASE(ELF, SHT_FINI_ARRAY);
283     STRINGIFY_ENUM_CASE(ELF, SHT_PREINIT_ARRAY);
284     STRINGIFY_ENUM_CASE(ELF, SHT_GROUP);
285     STRINGIFY_ENUM_CASE(ELF, SHT_SYMTAB_SHNDX);
286     STRINGIFY_ENUM_CASE(ELF, SHT_RELR);
287     STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_REL);
288     STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_RELA);
289     STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_RELR);
290     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_ODRTAB);
291     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_LINKER_OPTIONS);
292     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_CALL_GRAPH_PROFILE);
293     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_ADDRSIG);
294     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_DEPENDENT_LIBRARIES);
295     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_SYMPART);
296     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_PART_EHDR);
297     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_PART_PHDR);
298     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_BB_ADDR_MAP_V0);
299     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_BB_ADDR_MAP);
300     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_OFFLOADING);
301     STRINGIFY_ENUM_CASE(ELF, SHT_GNU_ATTRIBUTES);
302     STRINGIFY_ENUM_CASE(ELF, SHT_GNU_HASH);
303     STRINGIFY_ENUM_CASE(ELF, SHT_GNU_verdef);
304     STRINGIFY_ENUM_CASE(ELF, SHT_GNU_verneed);
305     STRINGIFY_ENUM_CASE(ELF, SHT_GNU_versym);
306   default:
307     return "Unknown";
308   }
309 }
310 
311 template <class ELFT>
312 std::vector<typename ELFT::Rel>
313 ELFFile<ELFT>::decode_relrs(Elf_Relr_Range relrs) const {
314   // This function decodes the contents of an SHT_RELR packed relocation
315   // section.
316   //
317   // Proposal for adding SHT_RELR sections to generic-abi is here:
318   //   https://groups.google.com/forum/#!topic/generic-abi/bX460iggiKg
319   //
320   // The encoded sequence of Elf64_Relr entries in a SHT_RELR section looks
321   // like [ AAAAAAAA BBBBBBB1 BBBBBBB1 ... AAAAAAAA BBBBBB1 ... ]
322   //
323   // i.e. start with an address, followed by any number of bitmaps. The address
324   // entry encodes 1 relocation. The subsequent bitmap entries encode up to 63
325   // relocations each, at subsequent offsets following the last address entry.
326   //
327   // The bitmap entries must have 1 in the least significant bit. The assumption
328   // here is that an address cannot have 1 in lsb. Odd addresses are not
329   // supported.
330   //
331   // Excluding the least significant bit in the bitmap, each non-zero bit in
332   // the bitmap represents a relocation to be applied to a corresponding machine
333   // word that follows the base address word. The second least significant bit
334   // represents the machine word immediately following the initial address, and
335   // each bit that follows represents the next word, in linear order. As such,
336   // a single bitmap can encode up to 31 relocations in a 32-bit object, and
337   // 63 relocations in a 64-bit object.
338   //
339   // This encoding has a couple of interesting properties:
340   // 1. Looking at any entry, it is clear whether it's an address or a bitmap:
341   //    even means address, odd means bitmap.
342   // 2. Just a simple list of addresses is a valid encoding.
343 
344   Elf_Rel Rel;
345   Rel.r_info = 0;
346   Rel.setType(getRelativeRelocationType(), false);
347   std::vector<Elf_Rel> Relocs;
348 
349   // Word type: uint32_t for Elf32, and uint64_t for Elf64.
350   using Addr = typename ELFT::uint;
351 
352   Addr Base = 0;
353   for (Elf_Relr R : relrs) {
354     typename ELFT::uint Entry = R;
355     if ((Entry & 1) == 0) {
356       // Even entry: encodes the offset for next relocation.
357       Rel.r_offset = Entry;
358       Relocs.push_back(Rel);
359       // Set base offset for subsequent bitmap entries.
360       Base = Entry + sizeof(Addr);
361     } else {
362       // Odd entry: encodes bitmap for relocations starting at base.
363       for (Addr Offset = Base; (Entry >>= 1) != 0; Offset += sizeof(Addr))
364         if ((Entry & 1) != 0) {
365           Rel.r_offset = Offset;
366           Relocs.push_back(Rel);
367         }
368       Base += (CHAR_BIT * sizeof(Entry) - 1) * sizeof(Addr);
369     }
370   }
371 
372   return Relocs;
373 }
374 
375 template <class ELFT>
376 Expected<std::vector<typename ELFT::Rela>>
377 ELFFile<ELFT>::android_relas(const Elf_Shdr &Sec) const {
378   // This function reads relocations in Android's packed relocation format,
379   // which is based on SLEB128 and delta encoding.
380   Expected<ArrayRef<uint8_t>> ContentsOrErr = getSectionContents(Sec);
381   if (!ContentsOrErr)
382     return ContentsOrErr.takeError();
383   ArrayRef<uint8_t> Content = *ContentsOrErr;
384   if (Content.size() < 4 || Content[0] != 'A' || Content[1] != 'P' ||
385       Content[2] != 'S' || Content[3] != '2')
386     return createError("invalid packed relocation header");
387   DataExtractor Data(Content, isLE(), ELFT::Is64Bits ? 8 : 4);
388   DataExtractor::Cursor Cur(/*Offset=*/4);
389 
390   uint64_t NumRelocs = Data.getSLEB128(Cur);
391   uint64_t Offset = Data.getSLEB128(Cur);
392   uint64_t Addend = 0;
393 
394   if (!Cur)
395     return std::move(Cur.takeError());
396 
397   std::vector<Elf_Rela> Relocs;
398   Relocs.reserve(NumRelocs);
399   while (NumRelocs) {
400     uint64_t NumRelocsInGroup = Data.getSLEB128(Cur);
401     if (!Cur)
402       return std::move(Cur.takeError());
403     if (NumRelocsInGroup > NumRelocs)
404       return createError("relocation group unexpectedly large");
405     NumRelocs -= NumRelocsInGroup;
406 
407     uint64_t GroupFlags = Data.getSLEB128(Cur);
408     bool GroupedByInfo = GroupFlags & ELF::RELOCATION_GROUPED_BY_INFO_FLAG;
409     bool GroupedByOffsetDelta = GroupFlags & ELF::RELOCATION_GROUPED_BY_OFFSET_DELTA_FLAG;
410     bool GroupedByAddend = GroupFlags & ELF::RELOCATION_GROUPED_BY_ADDEND_FLAG;
411     bool GroupHasAddend = GroupFlags & ELF::RELOCATION_GROUP_HAS_ADDEND_FLAG;
412 
413     uint64_t GroupOffsetDelta;
414     if (GroupedByOffsetDelta)
415       GroupOffsetDelta = Data.getSLEB128(Cur);
416 
417     uint64_t GroupRInfo;
418     if (GroupedByInfo)
419       GroupRInfo = Data.getSLEB128(Cur);
420 
421     if (GroupedByAddend && GroupHasAddend)
422       Addend += Data.getSLEB128(Cur);
423 
424     if (!GroupHasAddend)
425       Addend = 0;
426 
427     for (uint64_t I = 0; Cur && I != NumRelocsInGroup; ++I) {
428       Elf_Rela R;
429       Offset += GroupedByOffsetDelta ? GroupOffsetDelta : Data.getSLEB128(Cur);
430       R.r_offset = Offset;
431       R.r_info = GroupedByInfo ? GroupRInfo : Data.getSLEB128(Cur);
432       if (GroupHasAddend && !GroupedByAddend)
433         Addend += Data.getSLEB128(Cur);
434       R.r_addend = Addend;
435       Relocs.push_back(R);
436     }
437     if (!Cur)
438       return std::move(Cur.takeError());
439   }
440 
441   return Relocs;
442 }
443 
444 template <class ELFT>
445 std::string ELFFile<ELFT>::getDynamicTagAsString(unsigned Arch,
446                                                  uint64_t Type) const {
447 #define DYNAMIC_STRINGIFY_ENUM(tag, value)                                     \
448   case value:                                                                  \
449     return #tag;
450 
451 #define DYNAMIC_TAG(n, v)
452   switch (Arch) {
453   case ELF::EM_AARCH64:
454     switch (Type) {
455 #define AARCH64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
456 #include "llvm/BinaryFormat/DynamicTags.def"
457 #undef AARCH64_DYNAMIC_TAG
458     }
459     break;
460 
461   case ELF::EM_HEXAGON:
462     switch (Type) {
463 #define HEXAGON_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
464 #include "llvm/BinaryFormat/DynamicTags.def"
465 #undef HEXAGON_DYNAMIC_TAG
466     }
467     break;
468 
469   case ELF::EM_MIPS:
470     switch (Type) {
471 #define MIPS_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
472 #include "llvm/BinaryFormat/DynamicTags.def"
473 #undef MIPS_DYNAMIC_TAG
474     }
475     break;
476 
477   case ELF::EM_PPC:
478     switch (Type) {
479 #define PPC_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
480 #include "llvm/BinaryFormat/DynamicTags.def"
481 #undef PPC_DYNAMIC_TAG
482     }
483     break;
484 
485   case ELF::EM_PPC64:
486     switch (Type) {
487 #define PPC64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
488 #include "llvm/BinaryFormat/DynamicTags.def"
489 #undef PPC64_DYNAMIC_TAG
490     }
491     break;
492 
493   case ELF::EM_RISCV:
494     switch (Type) {
495 #define RISCV_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
496 #include "llvm/BinaryFormat/DynamicTags.def"
497 #undef RISCV_DYNAMIC_TAG
498     }
499     break;
500   }
501 #undef DYNAMIC_TAG
502   switch (Type) {
503 // Now handle all dynamic tags except the architecture specific ones
504 #define AARCH64_DYNAMIC_TAG(name, value)
505 #define MIPS_DYNAMIC_TAG(name, value)
506 #define HEXAGON_DYNAMIC_TAG(name, value)
507 #define PPC_DYNAMIC_TAG(name, value)
508 #define PPC64_DYNAMIC_TAG(name, value)
509 #define RISCV_DYNAMIC_TAG(name, value)
510 // Also ignore marker tags such as DT_HIOS (maps to DT_VERNEEDNUM), etc.
511 #define DYNAMIC_TAG_MARKER(name, value)
512 #define DYNAMIC_TAG(name, value) case value: return #name;
513 #include "llvm/BinaryFormat/DynamicTags.def"
514 #undef DYNAMIC_TAG
515 #undef AARCH64_DYNAMIC_TAG
516 #undef MIPS_DYNAMIC_TAG
517 #undef HEXAGON_DYNAMIC_TAG
518 #undef PPC_DYNAMIC_TAG
519 #undef PPC64_DYNAMIC_TAG
520 #undef RISCV_DYNAMIC_TAG
521 #undef DYNAMIC_TAG_MARKER
522 #undef DYNAMIC_STRINGIFY_ENUM
523   default:
524     return "<unknown:>0x" + utohexstr(Type, true);
525   }
526 }
527 
528 template <class ELFT>
529 std::string ELFFile<ELFT>::getDynamicTagAsString(uint64_t Type) const {
530   return getDynamicTagAsString(getHeader().e_machine, Type);
531 }
532 
533 template <class ELFT>
534 Expected<typename ELFT::DynRange> ELFFile<ELFT>::dynamicEntries() const {
535   ArrayRef<Elf_Dyn> Dyn;
536 
537   auto ProgramHeadersOrError = program_headers();
538   if (!ProgramHeadersOrError)
539     return ProgramHeadersOrError.takeError();
540 
541   for (const Elf_Phdr &Phdr : *ProgramHeadersOrError) {
542     if (Phdr.p_type == ELF::PT_DYNAMIC) {
543       Dyn = makeArrayRef(
544           reinterpret_cast<const Elf_Dyn *>(base() + Phdr.p_offset),
545           Phdr.p_filesz / sizeof(Elf_Dyn));
546       break;
547     }
548   }
549 
550   // If we can't find the dynamic section in the program headers, we just fall
551   // back on the sections.
552   if (Dyn.empty()) {
553     auto SectionsOrError = sections();
554     if (!SectionsOrError)
555       return SectionsOrError.takeError();
556 
557     for (const Elf_Shdr &Sec : *SectionsOrError) {
558       if (Sec.sh_type == ELF::SHT_DYNAMIC) {
559         Expected<ArrayRef<Elf_Dyn>> DynOrError =
560             getSectionContentsAsArray<Elf_Dyn>(Sec);
561         if (!DynOrError)
562           return DynOrError.takeError();
563         Dyn = *DynOrError;
564         break;
565       }
566     }
567 
568     if (!Dyn.data())
569       return ArrayRef<Elf_Dyn>();
570   }
571 
572   if (Dyn.empty())
573     return createError("invalid empty dynamic section");
574 
575   if (Dyn.back().d_tag != ELF::DT_NULL)
576     return createError("dynamic sections must be DT_NULL terminated");
577 
578   return Dyn;
579 }
580 
581 template <class ELFT>
582 Expected<const uint8_t *>
583 ELFFile<ELFT>::toMappedAddr(uint64_t VAddr, WarningHandler WarnHandler) const {
584   auto ProgramHeadersOrError = program_headers();
585   if (!ProgramHeadersOrError)
586     return ProgramHeadersOrError.takeError();
587 
588   llvm::SmallVector<Elf_Phdr *, 4> LoadSegments;
589 
590   for (const Elf_Phdr &Phdr : *ProgramHeadersOrError)
591     if (Phdr.p_type == ELF::PT_LOAD)
592       LoadSegments.push_back(const_cast<Elf_Phdr *>(&Phdr));
593 
594   auto SortPred = [](const Elf_Phdr_Impl<ELFT> *A,
595                      const Elf_Phdr_Impl<ELFT> *B) {
596     return A->p_vaddr < B->p_vaddr;
597   };
598   if (!llvm::is_sorted(LoadSegments, SortPred)) {
599     if (Error E =
600             WarnHandler("loadable segments are unsorted by virtual address"))
601       return std::move(E);
602     llvm::stable_sort(LoadSegments, SortPred);
603   }
604 
605   const Elf_Phdr *const *I = llvm::upper_bound(
606       LoadSegments, VAddr, [](uint64_t VAddr, const Elf_Phdr_Impl<ELFT> *Phdr) {
607         return VAddr < Phdr->p_vaddr;
608       });
609 
610   if (I == LoadSegments.begin())
611     return createError("virtual address is not in any segment: 0x" +
612                        Twine::utohexstr(VAddr));
613   --I;
614   const Elf_Phdr &Phdr = **I;
615   uint64_t Delta = VAddr - Phdr.p_vaddr;
616   if (Delta >= Phdr.p_filesz)
617     return createError("virtual address is not in any segment: 0x" +
618                        Twine::utohexstr(VAddr));
619 
620   uint64_t Offset = Phdr.p_offset + Delta;
621   if (Offset >= getBufSize())
622     return createError("can't map virtual address 0x" +
623                        Twine::utohexstr(VAddr) + " to the segment with index " +
624                        Twine(&Phdr - (*ProgramHeadersOrError).data() + 1) +
625                        ": the segment ends at 0x" +
626                        Twine::utohexstr(Phdr.p_offset + Phdr.p_filesz) +
627                        ", which is greater than the file size (0x" +
628                        Twine::utohexstr(getBufSize()) + ")");
629 
630   return base() + Offset;
631 }
632 
633 template <class ELFT>
634 Expected<std::vector<BBAddrMap>>
635 ELFFile<ELFT>::decodeBBAddrMap(const Elf_Shdr &Sec) const {
636   Expected<ArrayRef<uint8_t>> ContentsOrErr = getSectionContents(Sec);
637   if (!ContentsOrErr)
638     return ContentsOrErr.takeError();
639   ArrayRef<uint8_t> Content = *ContentsOrErr;
640   DataExtractor Data(Content, isLE(), ELFT::Is64Bits ? 8 : 4);
641   std::vector<BBAddrMap> FunctionEntries;
642 
643   DataExtractor::Cursor Cur(0);
644   Error ULEBSizeErr = Error::success();
645   // Helper to extract and decode the next ULEB128 value as uint32_t.
646   // Returns zero and sets ULEBSizeErr if the ULEB128 value exceeds the uint32_t
647   // limit.
648   // Also returns zero if ULEBSizeErr is already in an error state.
649   auto ReadULEB128AsUInt32 = [&Data, &Cur, &ULEBSizeErr]() -> uint32_t {
650     // Bail out and do not extract data if ULEBSizeErr is already set.
651     if (ULEBSizeErr)
652       return 0;
653     uint64_t Offset = Cur.tell();
654     uint64_t Value = Data.getULEB128(Cur);
655     if (Value > UINT32_MAX) {
656       ULEBSizeErr = createError(
657           "ULEB128 value at offset 0x" + Twine::utohexstr(Offset) +
658           " exceeds UINT32_MAX (0x" + Twine::utohexstr(Value) + ")");
659       return 0;
660     }
661     return static_cast<uint32_t>(Value);
662   };
663 
664   uint8_t Version = 0;
665   while (!ULEBSizeErr && Cur && Cur.tell() < Content.size()) {
666     if (Sec.sh_type == ELF::SHT_LLVM_BB_ADDR_MAP) {
667       Version = Data.getU8(Cur);
668       if (!Cur)
669         break;
670       if (Version > 1)
671         return createError("unsupported SHT_LLVM_BB_ADDR_MAP version: " +
672                            Twine(static_cast<int>(Version)));
673       Data.getU8(Cur); // Feature byte
674     }
675     uintX_t Address = static_cast<uintX_t>(Data.getAddress(Cur));
676     uint32_t NumBlocks = ReadULEB128AsUInt32();
677     std::vector<BBAddrMap::BBEntry> BBEntries;
678     uint32_t PrevBBEndOffset = 0;
679     for (uint32_t BlockID = 0; !ULEBSizeErr && Cur && (BlockID < NumBlocks);
680          ++BlockID) {
681       uint32_t Offset = ReadULEB128AsUInt32();
682       uint32_t Size = ReadULEB128AsUInt32();
683       uint32_t Metadata = ReadULEB128AsUInt32();
684       if (Version >= 1) {
685         // Offset is calculated relative to the end of the previous BB.
686         Offset += PrevBBEndOffset;
687         PrevBBEndOffset = Offset + Size;
688       }
689       BBEntries.push_back({Offset, Size, Metadata});
690     }
691     FunctionEntries.push_back({Address, std::move(BBEntries)});
692   }
693   // Either Cur is in the error state, or ULEBSizeError is set (not both), but
694   // we join the two errors here to be safe.
695   if (!Cur || ULEBSizeErr)
696     return joinErrors(Cur.takeError(), std::move(ULEBSizeErr));
697   return FunctionEntries;
698 }
699 
700 template class llvm::object::ELFFile<ELF32LE>;
701 template class llvm::object::ELFFile<ELF32BE>;
702 template class llvm::object::ELFFile<ELF64LE>;
703 template class llvm::object::ELFFile<ELF64BE>;
704