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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 
24 namespace llvm {
25 namespace ARM {
26 namespace EHABI {
27 
28 class 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 
65 public:
OpcodeDecoder(StreamWriter & SW)66   OpcodeDecoder(StreamWriter &SW) : SW(SW), OS(SW.getOStream()) {}
67   void Decode(const uint8_t *Opcodes, off_t Offset, size_t Length);
68 };
69 
70 const 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 
Decode_00xxxxxx(const uint8_t * Opcodes,unsigned & OI)95 void 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 }
Decode_01xxxxxx(const uint8_t * Opcodes,unsigned & OI)100 void 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 }
Decode_1000iiii_iiiiiiii(const uint8_t * Opcodes,unsigned & OI)105 void 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 }
Decode_10011101(const uint8_t * Opcodes,unsigned & OI)118 void 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 }
Decode_10011111(const uint8_t * Opcodes,unsigned & OI)122 void 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 }
Decode_1001nnnn(const uint8_t * Opcodes,unsigned & OI)126 void 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 }
Decode_10100nnn(const uint8_t * Opcodes,unsigned & OI)130 void 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 }
Decode_10101nnn(const uint8_t * Opcodes,unsigned & OI)136 void 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 }
Decode_10110000(const uint8_t * Opcodes,unsigned & OI)142 void 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 }
Decode_10110001_0000iiii(const uint8_t * Opcodes,unsigned & OI)146 void 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 }
Decode_10110010_uleb128(const uint8_t * Opcodes,unsigned & OI)158 void 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 }
Decode_10110011_sssscccc(const uint8_t * Opcodes,unsigned & OI)175 void 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 }
Decode_101101nn(const uint8_t * Opcodes,unsigned & OI)185 void 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 }
Decode_10111nnn(const uint8_t * Opcodes,unsigned & OI)189 void 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 }
Decode_11000110_sssscccc(const uint8_t * Opcodes,unsigned & OI)195 void 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 }
Decode_11000111_0000iiii(const uint8_t * Opcodes,unsigned & OI)205 void 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 }
Decode_11001000_sssscccc(const uint8_t * Opcodes,unsigned & OI)216 void 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 }
Decode_11001001_sssscccc(const uint8_t * Opcodes,unsigned & OI)226 void 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 }
Decode_11001yyy(const uint8_t * Opcodes,unsigned & OI)236 void 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 }
Decode_11000nnn(const uint8_t * Opcodes,unsigned & OI)240 void 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 }
Decode_11010nnn(const uint8_t * Opcodes,unsigned & OI)246 void 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 }
Decode_11xxxyyy(const uint8_t * Opcodes,unsigned & OI)252 void 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 
PrintGPR(uint16_t GPRMask)257 void 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 
PrintRegisters(uint32_t VFPMask,StringRef Prefix)276 void 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 
Decode(const uint8_t * Opcodes,off_t Offset,size_t Length)290 void 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 
306 template <typename ET>
307 class 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 
PREL31(uint32_t Address,uint32_t Place)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 
336 public:
PrinterContext(StreamWriter & Writer,const object::ELFFile<ET> * File)337   PrinterContext(StreamWriter &Writer, const object::ELFFile<ET> *File)
338     : SW(Writer), ELF(File) {}
339 
340   void PrintUnwindInformation() const;
341 };
342 
343 template <typename ET>
344 const size_t PrinterContext<ET>::IndexTableEntrySize = 8;
345 
346 template <typename ET>
FunctionAtAddress(unsigned Section,uint64_t Address)347 ErrorOr<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 
357 template <typename ET>
358 const typename object::ELFFile<ET>::Elf_Shdr *
FindExceptionTable(unsigned IndexSectionIndex,off_t IndexTableOffset)359 PrinterContext<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 
391 template <typename ET>
PrintExceptionTable(const Elf_Shdr * IT,const Elf_Shdr * EHT,uint64_t TableEntryOffset)392 void 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 
452 template <typename ET>
PrintOpcodes(const uint8_t * Entry,size_t Length,off_t Offset)453 void 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 
459 template <typename ET>
PrintIndexTable(unsigned SectionIndex,const Elf_Shdr * IT)460 void 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 
526 template <typename ET>
PrintUnwindInformation()527 void 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