1//===--- ARMEHABIPrinter.h - ARM EHABI Unwind Information Printer ----------===//
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#ifndef LLVM_READOBJ_ARMEHABI_PRINTER_H
11#define LLVM_READOBJ_ARMEHABI_PRINTER_H
12
13#include "Error.h"
14#include "StreamWriter.h"
15#include "llvm/ADT/STLExtras.h"
16#include "llvm/Object/ELF.h"
17#include "llvm/Object/ELFTypes.h"
18#include "llvm/Support/ARMEHABI.h"
19#include "llvm/Support/Debug.h"
20#include "llvm/Support/Endian.h"
21#include "llvm/Support/Format.h"
22#include "llvm/Support/type_traits.h"
23
24namespace llvm {
25namespace ARM {
26namespace EHABI {
27
28class OpcodeDecoder {
29  StreamWriter &SW;
30  raw_ostream &OS;
31
32  struct RingEntry {
33    uint8_t Mask;
34    uint8_t Value;
35    void (OpcodeDecoder::*Routine)(const uint8_t *Opcodes, unsigned &OI);
36  };
37  static const RingEntry Ring[];
38
39  void Decode_00xxxxxx(const uint8_t *Opcodes, unsigned &OI);
40  void Decode_01xxxxxx(const uint8_t *Opcodes, unsigned &OI);
41  void Decode_1000iiii_iiiiiiii(const uint8_t *Opcodes, unsigned &OI);
42  void Decode_10011101(const uint8_t *Opcodes, unsigned &OI);
43  void Decode_10011111(const uint8_t *Opcodes, unsigned &OI);
44  void Decode_1001nnnn(const uint8_t *Opcodes, unsigned &OI);
45  void Decode_10100nnn(const uint8_t *Opcodes, unsigned &OI);
46  void Decode_10101nnn(const uint8_t *Opcodes, unsigned &OI);
47  void Decode_10110000(const uint8_t *Opcodes, unsigned &OI);
48  void Decode_10110001_0000iiii(const uint8_t *Opcodes, unsigned &OI);
49  void Decode_10110010_uleb128(const uint8_t *Opcodes, unsigned &OI);
50  void Decode_10110011_sssscccc(const uint8_t *Opcodes, unsigned &OI);
51  void Decode_101101nn(const uint8_t *Opcodes, unsigned &OI);
52  void Decode_10111nnn(const uint8_t *Opcodes, unsigned &OI);
53  void Decode_11000110_sssscccc(const uint8_t *Opcodes, unsigned &OI);
54  void Decode_11000111_0000iiii(const uint8_t *Opcodes, unsigned &OI);
55  void Decode_11001000_sssscccc(const uint8_t *Opcodes, unsigned &OI);
56  void Decode_11001001_sssscccc(const uint8_t *Opcodes, unsigned &OI);
57  void Decode_11001yyy(const uint8_t *Opcodes, unsigned &OI);
58  void Decode_11000nnn(const uint8_t *Opcodes, unsigned &OI);
59  void Decode_11010nnn(const uint8_t *Opcodes, unsigned &OI);
60  void Decode_11xxxyyy(const uint8_t *Opcodes, unsigned &OI);
61
62  void PrintGPR(uint16_t GPRMask);
63  void PrintRegisters(uint32_t Mask, StringRef Prefix);
64
65public:
66  OpcodeDecoder(StreamWriter &SW) : SW(SW), OS(SW.getOStream()) {}
67  void Decode(const uint8_t *Opcodes, off_t Offset, size_t Length);
68};
69
70const OpcodeDecoder::RingEntry OpcodeDecoder::Ring[] = {
71  { 0xc0, 0x00, &OpcodeDecoder::Decode_00xxxxxx },
72  { 0xc0, 0x40, &OpcodeDecoder::Decode_01xxxxxx },
73  { 0xf0, 0x80, &OpcodeDecoder::Decode_1000iiii_iiiiiiii },
74  { 0xff, 0x9d, &OpcodeDecoder::Decode_10011101 },
75  { 0xff, 0x9f, &OpcodeDecoder::Decode_10011111 },
76  { 0xf0, 0x90, &OpcodeDecoder::Decode_1001nnnn },
77  { 0xf8, 0xa0, &OpcodeDecoder::Decode_10100nnn },
78  { 0xf8, 0xa8, &OpcodeDecoder::Decode_10101nnn },
79  { 0xff, 0xb0, &OpcodeDecoder::Decode_10110000 },
80  { 0xff, 0xb1, &OpcodeDecoder::Decode_10110001_0000iiii },
81  { 0xff, 0xb2, &OpcodeDecoder::Decode_10110010_uleb128 },
82  { 0xff, 0xb3, &OpcodeDecoder::Decode_10110011_sssscccc },
83  { 0xfc, 0xb4, &OpcodeDecoder::Decode_101101nn },
84  { 0xf8, 0xb8, &OpcodeDecoder::Decode_10111nnn },
85  { 0xff, 0xc6, &OpcodeDecoder::Decode_11000110_sssscccc },
86  { 0xff, 0xc7, &OpcodeDecoder::Decode_11000111_0000iiii },
87  { 0xff, 0xc8, &OpcodeDecoder::Decode_11001000_sssscccc },
88  { 0xff, 0xc9, &OpcodeDecoder::Decode_11001001_sssscccc },
89  { 0xc8, 0xc8, &OpcodeDecoder::Decode_11001yyy },
90  { 0xf8, 0xc0, &OpcodeDecoder::Decode_11000nnn },
91  { 0xf8, 0xd0, &OpcodeDecoder::Decode_11010nnn },
92  { 0xc0, 0xc0, &OpcodeDecoder::Decode_11xxxyyy },
93};
94
95void OpcodeDecoder::Decode_00xxxxxx(const uint8_t *Opcodes, unsigned &OI) {
96  uint8_t Opcode = Opcodes[OI++ ^ 3];
97  SW.startLine() << format("0x%02X      ; vsp = vsp + %u\n", Opcode,
98                           ((Opcode & 0x3f) << 2) + 4);
99}
100void OpcodeDecoder::Decode_01xxxxxx(const uint8_t *Opcodes, unsigned &OI) {
101  uint8_t Opcode = Opcodes[OI++ ^ 3];
102  SW.startLine() << format("0x%02X      ; vsp = vsp - %u\n", Opcode,
103                           ((Opcode & 0x3f) << 2) + 4);
104}
105void OpcodeDecoder::Decode_1000iiii_iiiiiiii(const uint8_t *Opcodes,
106                                             unsigned &OI) {
107  uint8_t Opcode0 = Opcodes[OI++ ^ 3];
108  uint8_t Opcode1 = Opcodes[OI++ ^ 3];
109
110  uint16_t GPRMask = (Opcode1 << 4) | ((Opcode0 & 0x0f) << 12);
111  SW.startLine()
112    << format("0x%02X 0x%02X ; %s",
113              Opcode0, Opcode1, GPRMask ? "pop " : "refuse to unwind");
114  if (GPRMask)
115    PrintGPR(GPRMask);
116  OS << '\n';
117}
118void OpcodeDecoder::Decode_10011101(const uint8_t *Opcodes, unsigned &OI) {
119  uint8_t Opcode = Opcodes[OI++ ^ 3];
120  SW.startLine() << format("0x%02X      ; reserved (ARM MOVrr)\n", Opcode);
121}
122void OpcodeDecoder::Decode_10011111(const uint8_t *Opcodes, unsigned &OI) {
123  uint8_t Opcode = Opcodes[OI++ ^ 3];
124  SW.startLine() << format("0x%02X      ; reserved (WiMMX MOVrr)\n", Opcode);
125}
126void OpcodeDecoder::Decode_1001nnnn(const uint8_t *Opcodes, unsigned &OI) {
127  uint8_t Opcode = Opcodes[OI++ ^ 3];
128  SW.startLine() << format("0x%02X      ; vsp = r%u\n", Opcode, (Opcode & 0x0f));
129}
130void OpcodeDecoder::Decode_10100nnn(const uint8_t *Opcodes, unsigned &OI) {
131  uint8_t Opcode = Opcodes[OI++ ^ 3];
132  SW.startLine() << format("0x%02X      ; pop ", Opcode);
133  PrintGPR((((1 << ((Opcode & 0x7) + 1)) - 1) << 4));
134  OS << '\n';
135}
136void OpcodeDecoder::Decode_10101nnn(const uint8_t *Opcodes, unsigned &OI) {
137  uint8_t Opcode = Opcodes[OI++ ^ 3];
138  SW.startLine() << format("0x%02X      ; pop ", Opcode);
139  PrintGPR((((1 << ((Opcode & 0x7) + 1)) - 1) << 4) | (1 << 14));
140  OS << '\n';
141}
142void OpcodeDecoder::Decode_10110000(const uint8_t *Opcodes, unsigned &OI) {
143  uint8_t Opcode = Opcodes[OI++ ^ 3];
144  SW.startLine() << format("0x%02X      ; finish\n", Opcode);
145}
146void OpcodeDecoder::Decode_10110001_0000iiii(const uint8_t *Opcodes,
147                                             unsigned &OI) {
148  uint8_t Opcode0 = Opcodes[OI++ ^ 3];
149  uint8_t Opcode1 = Opcodes[OI++ ^ 3];
150
151  SW.startLine()
152    << format("0x%02X 0x%02X ; %s", Opcode0, Opcode1,
153              ((Opcode1 & 0xf0) || Opcode1 == 0x00) ? "spare" : "pop ");
154  if (((Opcode1 & 0xf0) == 0x00) && Opcode1)
155    PrintGPR((Opcode1 & 0x0f));
156  OS << '\n';
157}
158void OpcodeDecoder::Decode_10110010_uleb128(const uint8_t *Opcodes,
159                                            unsigned &OI) {
160  uint8_t Opcode = Opcodes[OI++ ^ 3];
161  SW.startLine() << format("0x%02X ", Opcode);
162
163  SmallVector<uint8_t, 4> ULEB;
164  do { ULEB.push_back(Opcodes[OI ^ 3]); } while (Opcodes[OI++ ^ 3] & 0x80);
165
166  for (unsigned BI = 0, BE = ULEB.size(); BI != BE; ++BI)
167    OS << format("0x%02X ", ULEB[BI]);
168
169  uint64_t Value = 0;
170  for (unsigned BI = 0, BE = ULEB.size(); BI != BE; ++BI)
171    Value = Value | ((ULEB[BI] & 0x7f) << (7 * BI));
172
173  OS << format("; vsp = vsp + %" PRIu64 "\n", 0x204 + (Value << 2));
174}
175void OpcodeDecoder::Decode_10110011_sssscccc(const uint8_t *Opcodes,
176                                             unsigned &OI) {
177  uint8_t Opcode0 = Opcodes[OI++ ^ 3];
178  uint8_t Opcode1 = Opcodes[OI++ ^ 3];
179  SW.startLine() << format("0x%02X 0x%02X ; pop ", Opcode0, Opcode1);
180  uint8_t Start = ((Opcode1 & 0xf0) >> 4);
181  uint8_t Count = ((Opcode1 & 0x0f) >> 0);
182  PrintRegisters((((1 << (Count + 1)) - 1) << Start), "d");
183  OS << '\n';
184}
185void OpcodeDecoder::Decode_101101nn(const uint8_t *Opcodes, unsigned &OI) {
186  uint8_t Opcode = Opcodes[OI++ ^ 3];
187  SW.startLine() << format("0x%02X      ; spare\n", Opcode);
188}
189void OpcodeDecoder::Decode_10111nnn(const uint8_t *Opcodes, unsigned &OI) {
190  uint8_t Opcode = Opcodes[OI++ ^ 3];
191  SW.startLine() << format("0x%02X      ; pop ", Opcode);
192  PrintRegisters((((1 << ((Opcode & 0x07) + 1)) - 1) << 8), "d");
193  OS << '\n';
194}
195void OpcodeDecoder::Decode_11000110_sssscccc(const uint8_t *Opcodes,
196                                             unsigned &OI) {
197  uint8_t Opcode0 = Opcodes[OI++ ^ 3];
198  uint8_t Opcode1 = Opcodes[OI++ ^ 3];
199  SW.startLine() << format("0x%02X 0x%02X ; pop ", Opcode0, Opcode1);
200  uint8_t Start = ((Opcode1 & 0xf0) >> 4);
201  uint8_t Count = ((Opcode1 & 0x0f) >> 0);
202  PrintRegisters((((1 << (Count + 1)) - 1) << Start), "wR");
203  OS << '\n';
204}
205void OpcodeDecoder::Decode_11000111_0000iiii(const uint8_t *Opcodes,
206                                             unsigned &OI) {
207  uint8_t Opcode0 = Opcodes[OI++ ^ 3];
208  uint8_t Opcode1 = Opcodes[OI++ ^ 3];
209  SW.startLine()
210    << format("0x%02X 0x%02X ; %s", Opcode0, Opcode1,
211              ((Opcode1 & 0xf0) || Opcode1 == 0x00) ? "spare" : "pop ");
212  if ((Opcode1 & 0xf0) == 0x00 && Opcode1)
213      PrintRegisters(Opcode1 & 0x0f, "wCGR");
214  OS << '\n';
215}
216void OpcodeDecoder::Decode_11001000_sssscccc(const uint8_t *Opcodes,
217                                             unsigned &OI) {
218  uint8_t Opcode0 = Opcodes[OI++ ^ 3];
219  uint8_t Opcode1 = Opcodes[OI++ ^ 3];
220  SW.startLine() << format("0x%02X 0x%02X ; pop ", Opcode0, Opcode1);
221  uint8_t Start = 16 + ((Opcode1 & 0xf0) >> 4);
222  uint8_t Count = ((Opcode1 & 0x0f) >> 0);
223  PrintRegisters((((1 << (Count + 1)) - 1) << Start), "d");
224  OS << '\n';
225}
226void OpcodeDecoder::Decode_11001001_sssscccc(const uint8_t *Opcodes,
227                                             unsigned &OI) {
228  uint8_t Opcode0 = Opcodes[OI++ ^ 3];
229  uint8_t Opcode1 = Opcodes[OI++ ^ 3];
230  SW.startLine() << format("0x%02X 0x%02X ; pop ", Opcode0, Opcode1);
231  uint8_t Start = ((Opcode1 & 0xf0) >> 4);
232  uint8_t Count = ((Opcode1 & 0x0f) >> 0);
233  PrintRegisters((((1 << (Count + 1)) - 1) << Start), "d");
234  OS << '\n';
235}
236void OpcodeDecoder::Decode_11001yyy(const uint8_t *Opcodes, unsigned &OI) {
237  uint8_t Opcode = Opcodes[OI++ ^ 3];
238  SW.startLine() << format("0x%02X      ; spare\n", Opcode);
239}
240void OpcodeDecoder::Decode_11000nnn(const uint8_t *Opcodes, unsigned &OI) {
241  uint8_t Opcode = Opcodes[OI++ ^ 3];
242  SW.startLine() << format("0x%02X      ; pop ", Opcode);
243  PrintRegisters((((1 << ((Opcode & 0x07) + 1)) - 1) << 10), "wR");
244  OS << '\n';
245}
246void OpcodeDecoder::Decode_11010nnn(const uint8_t *Opcodes, unsigned &OI) {
247  uint8_t Opcode = Opcodes[OI++ ^ 3];
248  SW.startLine() << format("0x%02X      ; pop ", Opcode);
249  PrintRegisters((((1 << ((Opcode & 0x07) + 1)) - 1) << 8), "d");
250  OS << '\n';
251}
252void OpcodeDecoder::Decode_11xxxyyy(const uint8_t *Opcodes, unsigned &OI) {
253  uint8_t Opcode = Opcodes[OI++ ^ 3];
254  SW.startLine() << format("0x%02X      ; spare\n", Opcode);
255}
256
257void OpcodeDecoder::PrintGPR(uint16_t GPRMask) {
258  static const char *GPRRegisterNames[16] = {
259    "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10",
260    "fp", "ip", "sp", "lr", "pc"
261  };
262
263  OS << '{';
264  bool Comma = false;
265  for (unsigned RI = 0, RE = 17; RI < RE; ++RI) {
266    if (GPRMask & (1 << RI)) {
267      if (Comma)
268        OS << ", ";
269      OS << GPRRegisterNames[RI];
270      Comma = true;
271    }
272  }
273  OS << '}';
274}
275
276void OpcodeDecoder::PrintRegisters(uint32_t VFPMask, StringRef Prefix) {
277  OS << '{';
278  bool Comma = false;
279  for (unsigned RI = 0, RE = 32; RI < RE; ++RI) {
280    if (VFPMask & (1 << RI)) {
281      if (Comma)
282        OS << ", ";
283      OS << Prefix << RI;
284      Comma = true;
285    }
286  }
287  OS << '}';
288}
289
290void OpcodeDecoder::Decode(const uint8_t *Opcodes, off_t Offset, size_t Length) {
291  for (unsigned OCI = Offset; OCI < Length + Offset; ) {
292    bool Decoded = false;
293    for (unsigned REI = 0, REE = array_lengthof(Ring);
294         REI != REE && !Decoded; ++REI) {
295      if ((Opcodes[OCI ^ 3] & Ring[REI].Mask) == Ring[REI].Value) {
296        (this->*Ring[REI].Routine)(Opcodes, OCI);
297        Decoded = true;
298        break;
299      }
300    }
301    if (!Decoded)
302      SW.startLine() << format("0x%02X      ; reserved\n", Opcodes[OCI++ ^ 3]);
303  }
304}
305
306template <typename ET>
307class PrinterContext {
308  StreamWriter &SW;
309  const object::ELFFile<ET> *ELF;
310
311  typedef typename object::ELFFile<ET>::Elf_Sym Elf_Sym;
312  typedef typename object::ELFFile<ET>::Elf_Shdr Elf_Shdr;
313
314  typedef typename object::ELFFile<ET>::Elf_Rel_Iter Elf_Rel_iterator;
315  typedef typename object::ELFFile<ET>::Elf_Sym_Iter Elf_Sym_iterator;
316  typedef typename object::ELFFile<ET>::Elf_Shdr_Iter Elf_Shdr_iterator;
317
318  static const size_t IndexTableEntrySize;
319
320  static uint64_t PREL31(uint32_t Address, uint32_t Place) {
321    uint64_t Location = Address & 0x7fffffff;
322    if (Location & 0x04000000)
323      Location |= (uint64_t) ~0x7fffffff;
324    return Location + Place;
325  }
326
327  ErrorOr<StringRef> FunctionAtAddress(unsigned Section, uint64_t Address) const;
328  const Elf_Shdr *FindExceptionTable(unsigned IndexTableIndex,
329                                     off_t IndexTableOffset) const;
330
331  void PrintIndexTable(unsigned SectionIndex, const Elf_Shdr *IT) const;
332  void PrintExceptionTable(const Elf_Shdr *IT, const Elf_Shdr *EHT,
333                           uint64_t TableEntryOffset) const;
334  void PrintOpcodes(const uint8_t *Entry, size_t Length, off_t Offset) const;
335
336public:
337  PrinterContext(StreamWriter &Writer, const object::ELFFile<ET> *File)
338    : SW(Writer), ELF(File) {}
339
340  void PrintUnwindInformation() const;
341};
342
343template <typename ET>
344const size_t PrinterContext<ET>::IndexTableEntrySize = 8;
345
346template <typename ET>
347ErrorOr<StringRef> PrinterContext<ET>::FunctionAtAddress(unsigned Section,
348                                                         uint64_t Address) const {
349  for (Elf_Sym_iterator SI = ELF->begin_symbols(), SE = ELF->end_symbols();
350       SI != SE; ++SI)
351    if (SI->st_shndx == Section && SI->st_value == Address &&
352        SI->getType() == ELF::STT_FUNC)
353      return ELF->getSymbolName(SI);
354  return readobj_error::unknown_symbol;
355}
356
357template <typename ET>
358const typename object::ELFFile<ET>::Elf_Shdr *
359PrinterContext<ET>::FindExceptionTable(unsigned IndexSectionIndex,
360                                       off_t IndexTableOffset) const {
361  /// Iterate through the sections, searching for the relocation section
362  /// associated with the unwind index table section specified by
363  /// IndexSectionIndex.  Iterate the associated section searching for the
364  /// relocation associated with the index table entry specified by
365  /// IndexTableOffset.  The symbol is the section symbol for the exception
366  /// handling table.  Use this symbol to recover the actual exception handling
367  /// table.
368
369  for (Elf_Shdr_iterator SI = ELF->begin_sections(), SE = ELF->end_sections();
370       SI != SE; ++SI) {
371    if (SI->sh_type == ELF::SHT_REL && SI->sh_info == IndexSectionIndex) {
372      for (Elf_Rel_iterator RI = ELF->begin_rel(&*SI), RE = ELF->end_rel(&*SI);
373           RI != RE; ++RI) {
374        if (RI->r_offset == static_cast<unsigned>(IndexTableOffset)) {
375          typename object::ELFFile<ET>::Elf_Rela RelA;
376          RelA.r_offset = RI->r_offset;
377          RelA.r_info = RI->r_info;
378          RelA.r_addend = 0;
379
380          std::pair<const Elf_Shdr *, const Elf_Sym *> Symbol =
381            ELF->getRelocationSymbol(&(*SI), &RelA);
382
383          return ELF->getSection(Symbol.second);
384        }
385      }
386    }
387  }
388  return nullptr;
389}
390
391template <typename ET>
392void PrinterContext<ET>::PrintExceptionTable(const Elf_Shdr *IT,
393                                             const Elf_Shdr *EHT,
394                                             uint64_t TableEntryOffset) const {
395  ErrorOr<ArrayRef<uint8_t> > Contents = ELF->getSectionContents(EHT);
396  if (!Contents)
397    return;
398
399  /// ARM EHABI Section 6.2 - The generic model
400  ///
401  /// An exception-handling table entry for the generic model is laid out as:
402  ///
403  ///  3 3
404  ///  1 0                            0
405  /// +-+------------------------------+
406  /// |0|  personality routine offset  |
407  /// +-+------------------------------+
408  /// |  personality routine data ...  |
409  ///
410  ///
411  /// ARM EHABI Section 6.3 - The ARM-defined compact model
412  ///
413  /// An exception-handling table entry for the compact model looks like:
414  ///
415  ///  3 3 2 2  2 2
416  ///  1 0 8 7  4 3                     0
417  /// +-+---+----+-----------------------+
418  /// |1| 0 | Ix | data for pers routine |
419  /// +-+---+----+-----------------------+
420  /// |  more personality routine data   |
421
422  const support::ulittle32_t Word =
423    *reinterpret_cast<const support::ulittle32_t *>(Contents->data() + TableEntryOffset);
424
425  if (Word & 0x80000000) {
426    SW.printString("Model", StringRef("Compact"));
427
428    unsigned PersonalityIndex = (Word & 0x0f000000) >> 24;
429    SW.printNumber("PersonalityIndex", PersonalityIndex);
430
431    switch (PersonalityIndex) {
432    case AEABI_UNWIND_CPP_PR0:
433      PrintOpcodes(Contents->data() + TableEntryOffset, 3, 1);
434      break;
435    case AEABI_UNWIND_CPP_PR1:
436    case AEABI_UNWIND_CPP_PR2:
437      unsigned AdditionalWords = (Word & 0x00ff0000) >> 16;
438      PrintOpcodes(Contents->data() + TableEntryOffset, 2 + 4 * AdditionalWords,
439                   2);
440      break;
441    }
442  } else {
443    SW.printString("Model", StringRef("Generic"));
444
445    uint64_t Address = PREL31(Word, EHT->sh_addr);
446    SW.printHex("PersonalityRoutineAddress", Address);
447    if (ErrorOr<StringRef> Name = FunctionAtAddress(EHT->sh_link, Address))
448      SW.printString("PersonalityRoutineName", *Name);
449  }
450}
451
452template <typename ET>
453void PrinterContext<ET>::PrintOpcodes(const uint8_t *Entry,
454                                      size_t Length, off_t Offset) const {
455  ListScope OCC(SW, "Opcodes");
456  OpcodeDecoder(OCC.W).Decode(Entry, Offset, Length);
457}
458
459template <typename ET>
460void PrinterContext<ET>::PrintIndexTable(unsigned SectionIndex,
461                                         const Elf_Shdr *IT) const {
462  ErrorOr<ArrayRef<uint8_t> > Contents = ELF->getSectionContents(IT);
463  if (!Contents)
464    return;
465
466  /// ARM EHABI Section 5 - Index Table Entries
467  /// * The first word contains a PREL31 offset to the start of a function with
468  ///   bit 31 clear
469  /// * The second word contains one of:
470  ///   - The PREL31 offset of the start of the table entry for the function,
471  ///     with bit 31 clear
472  ///   - The exception-handling table entry itself with bit 31 set
473  ///   - The special bit pattern EXIDX_CANTUNWIND, indicating that associated
474  ///     frames cannot be unwound
475
476  const support::ulittle32_t *Data =
477    reinterpret_cast<const support::ulittle32_t *>(Contents->data());
478  const unsigned Entries = IT->sh_size / IndexTableEntrySize;
479
480  ListScope E(SW, "Entries");
481  for (unsigned Entry = 0; Entry < Entries; ++Entry) {
482    DictScope E(SW, "Entry");
483
484    const support::ulittle32_t Word0 =
485      Data[Entry * (IndexTableEntrySize / sizeof(*Data)) + 0];
486    const support::ulittle32_t Word1 =
487      Data[Entry * (IndexTableEntrySize / sizeof(*Data)) + 1];
488
489    if (Word0 & 0x80000000) {
490      errs() << "corrupt unwind data in section " << SectionIndex << "\n";
491      continue;
492    }
493
494    const uint64_t Offset = PREL31(Word0, IT->sh_addr);
495    SW.printHex("FunctionAddress", Offset);
496    if (ErrorOr<StringRef> Name = FunctionAtAddress(IT->sh_link, Offset))
497      SW.printString("FunctionName", *Name);
498
499    if (Word1 == EXIDX_CANTUNWIND) {
500      SW.printString("Model", StringRef("CantUnwind"));
501      continue;
502    }
503
504    if (Word1 & 0x80000000) {
505      SW.printString("Model", StringRef("Compact (Inline)"));
506
507      unsigned PersonalityIndex = (Word1 & 0x0f000000) >> 24;
508      SW.printNumber("PersonalityIndex", PersonalityIndex);
509
510      PrintOpcodes(Contents->data() + Entry * IndexTableEntrySize + 4, 3, 1);
511    } else {
512      const Elf_Shdr *EHT =
513        FindExceptionTable(SectionIndex, Entry * IndexTableEntrySize + 4);
514
515      if (ErrorOr<StringRef> Name = ELF->getSectionName(EHT))
516        SW.printString("ExceptionHandlingTable", *Name);
517
518      uint64_t TableEntryOffset = PREL31(Word1, IT->sh_addr);
519      SW.printHex("TableEntryOffset", TableEntryOffset);
520
521      PrintExceptionTable(IT, EHT, TableEntryOffset);
522    }
523  }
524}
525
526template <typename ET>
527void PrinterContext<ET>::PrintUnwindInformation() const {
528  DictScope UI(SW, "UnwindInformation");
529
530  int SectionIndex = 0;
531  for (Elf_Shdr_iterator SI = ELF->begin_sections(), SE = ELF->end_sections();
532       SI != SE; ++SI, ++SectionIndex) {
533    if (SI->sh_type == ELF::SHT_ARM_EXIDX) {
534      const Elf_Shdr *IT = &(*SI);
535
536      DictScope UIT(SW, "UnwindIndexTable");
537
538      SW.printNumber("SectionIndex", SectionIndex);
539      if (ErrorOr<StringRef> SectionName = ELF->getSectionName(IT))
540        SW.printString("SectionName", *SectionName);
541      SW.printHex("SectionOffset", IT->sh_offset);
542
543      PrintIndexTable(SectionIndex, IT);
544    }
545  }
546}
547}
548}
549}
550
551#endif
552
553