1 //===-- DWARFExpression.cpp -------------------------------------*- 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 #include "lldb/Expression/DWARFExpression.h"
11 
12 // C Includes
13 #include <inttypes.h>
14 
15 // C++ Includes
16 #include <vector>
17 
18 #include "lldb/Core/RegisterValue.h"
19 #include "lldb/Core/Scalar.h"
20 #include "lldb/Core/Value.h"
21 #include "lldb/Core/dwarf.h"
22 #include "lldb/Utility/DataEncoder.h"
23 #include "lldb/Utility/Log.h"
24 #include "lldb/Utility/StreamString.h"
25 #include "lldb/Utility/VMRange.h"
26 
27 #include "lldb/Host/Host.h"
28 #include "lldb/Utility/Endian.h"
29 
30 #include "lldb/Symbol/Function.h"
31 
32 #include "lldb/Target/ABI.h"
33 #include "lldb/Target/ExecutionContext.h"
34 #include "lldb/Target/Process.h"
35 #include "lldb/Target/RegisterContext.h"
36 #include "lldb/Target/StackFrame.h"
37 #include "lldb/Target/StackID.h"
38 #include "lldb/Target/Thread.h"
39 
40 #include "Plugins/SymbolFile/DWARF/DWARFUnit.h"
41 
42 using namespace lldb;
43 using namespace lldb_private;
44 
45 static lldb::addr_t
46 ReadAddressFromDebugAddrSection(const DWARFUnit *dwarf_cu,
47                                 uint32_t index) {
48   uint32_t index_size = dwarf_cu->GetAddressByteSize();
49   dw_offset_t addr_base = dwarf_cu->GetAddrBase();
50   lldb::offset_t offset = addr_base + index * index_size;
51   return dwarf_cu->GetSymbolFileDWARF()->get_debug_addr_data().GetMaxU64(
52       &offset, index_size);
53 }
54 
55 //----------------------------------------------------------------------
56 // DWARFExpression constructor
57 //----------------------------------------------------------------------
58 DWARFExpression::DWARFExpression(DWARFUnit *dwarf_cu)
59     : m_module_wp(), m_data(), m_dwarf_cu(dwarf_cu),
60       m_reg_kind(eRegisterKindDWARF), m_loclist_slide(LLDB_INVALID_ADDRESS) {}
61 
62 DWARFExpression::DWARFExpression(const DWARFExpression &rhs)
63     : m_module_wp(rhs.m_module_wp), m_data(rhs.m_data),
64       m_dwarf_cu(rhs.m_dwarf_cu), m_reg_kind(rhs.m_reg_kind),
65       m_loclist_slide(rhs.m_loclist_slide) {}
66 
67 DWARFExpression::DWARFExpression(lldb::ModuleSP module_sp,
68                                  const DataExtractor &data,
69                                  DWARFUnit *dwarf_cu,
70                                  lldb::offset_t data_offset,
71                                  lldb::offset_t data_length)
72     : m_module_wp(), m_data(data, data_offset, data_length),
73       m_dwarf_cu(dwarf_cu), m_reg_kind(eRegisterKindDWARF),
74       m_loclist_slide(LLDB_INVALID_ADDRESS) {
75   if (module_sp)
76     m_module_wp = module_sp;
77 }
78 
79 //----------------------------------------------------------------------
80 // Destructor
81 //----------------------------------------------------------------------
82 DWARFExpression::~DWARFExpression() {}
83 
84 bool DWARFExpression::IsValid() const { return m_data.GetByteSize() > 0; }
85 
86 void DWARFExpression::SetOpcodeData(const DataExtractor &data) {
87   m_data = data;
88 }
89 
90 void DWARFExpression::CopyOpcodeData(lldb::ModuleSP module_sp,
91                                      const DataExtractor &data,
92                                      lldb::offset_t data_offset,
93                                      lldb::offset_t data_length) {
94   const uint8_t *bytes = data.PeekData(data_offset, data_length);
95   if (bytes) {
96     m_module_wp = module_sp;
97     m_data.SetData(DataBufferSP(new DataBufferHeap(bytes, data_length)));
98     m_data.SetByteOrder(data.GetByteOrder());
99     m_data.SetAddressByteSize(data.GetAddressByteSize());
100   }
101 }
102 
103 void DWARFExpression::CopyOpcodeData(const void *data,
104                                      lldb::offset_t data_length,
105                                      ByteOrder byte_order,
106                                      uint8_t addr_byte_size) {
107   if (data && data_length) {
108     m_data.SetData(DataBufferSP(new DataBufferHeap(data, data_length)));
109     m_data.SetByteOrder(byte_order);
110     m_data.SetAddressByteSize(addr_byte_size);
111   }
112 }
113 
114 void DWARFExpression::CopyOpcodeData(uint64_t const_value,
115                                      lldb::offset_t const_value_byte_size,
116                                      uint8_t addr_byte_size) {
117   if (const_value_byte_size) {
118     m_data.SetData(
119         DataBufferSP(new DataBufferHeap(&const_value, const_value_byte_size)));
120     m_data.SetByteOrder(endian::InlHostByteOrder());
121     m_data.SetAddressByteSize(addr_byte_size);
122   }
123 }
124 
125 void DWARFExpression::SetOpcodeData(lldb::ModuleSP module_sp,
126                                     const DataExtractor &data,
127                                     lldb::offset_t data_offset,
128                                     lldb::offset_t data_length) {
129   m_module_wp = module_sp;
130   m_data.SetData(data, data_offset, data_length);
131 }
132 
133 void DWARFExpression::DumpLocation(Stream *s, lldb::offset_t offset,
134                                    lldb::offset_t length,
135                                    lldb::DescriptionLevel level,
136                                    ABI *abi) const {
137   if (!m_data.ValidOffsetForDataOfSize(offset, length))
138     return;
139   const lldb::offset_t start_offset = offset;
140   const lldb::offset_t end_offset = offset + length;
141   while (m_data.ValidOffset(offset) && offset < end_offset) {
142     const lldb::offset_t op_offset = offset;
143     const uint8_t op = m_data.GetU8(&offset);
144 
145     switch (level) {
146     default:
147       break;
148 
149     case lldb::eDescriptionLevelBrief:
150       if (offset > start_offset)
151         s->PutChar(' ');
152       break;
153 
154     case lldb::eDescriptionLevelFull:
155     case lldb::eDescriptionLevelVerbose:
156       if (offset > start_offset)
157         s->EOL();
158       s->Indent();
159       if (level == lldb::eDescriptionLevelFull)
160         break;
161       // Fall through for verbose and print offset and DW_OP prefix..
162       s->Printf("0x%8.8" PRIx64 ": %s", op_offset,
163                 op >= DW_OP_APPLE_uninit ? "DW_OP_APPLE_" : "DW_OP_");
164       break;
165     }
166 
167     switch (op) {
168     case DW_OP_addr:
169       *s << "DW_OP_addr(" << m_data.GetAddress(&offset) << ") ";
170       break; // 0x03 1 address
171     case DW_OP_deref:
172       *s << "DW_OP_deref";
173       break; // 0x06
174     case DW_OP_const1u:
175       s->Printf("DW_OP_const1u(0x%2.2x) ", m_data.GetU8(&offset));
176       break; // 0x08 1 1-byte constant
177     case DW_OP_const1s:
178       s->Printf("DW_OP_const1s(0x%2.2x) ", m_data.GetU8(&offset));
179       break; // 0x09 1 1-byte constant
180     case DW_OP_const2u:
181       s->Printf("DW_OP_const2u(0x%4.4x) ", m_data.GetU16(&offset));
182       break; // 0x0a 1 2-byte constant
183     case DW_OP_const2s:
184       s->Printf("DW_OP_const2s(0x%4.4x) ", m_data.GetU16(&offset));
185       break; // 0x0b 1 2-byte constant
186     case DW_OP_const4u:
187       s->Printf("DW_OP_const4u(0x%8.8x) ", m_data.GetU32(&offset));
188       break; // 0x0c 1 4-byte constant
189     case DW_OP_const4s:
190       s->Printf("DW_OP_const4s(0x%8.8x) ", m_data.GetU32(&offset));
191       break; // 0x0d 1 4-byte constant
192     case DW_OP_const8u:
193       s->Printf("DW_OP_const8u(0x%16.16" PRIx64 ") ", m_data.GetU64(&offset));
194       break; // 0x0e 1 8-byte constant
195     case DW_OP_const8s:
196       s->Printf("DW_OP_const8s(0x%16.16" PRIx64 ") ", m_data.GetU64(&offset));
197       break; // 0x0f 1 8-byte constant
198     case DW_OP_constu:
199       s->Printf("DW_OP_constu(0x%" PRIx64 ") ", m_data.GetULEB128(&offset));
200       break; // 0x10 1 ULEB128 constant
201     case DW_OP_consts:
202       s->Printf("DW_OP_consts(0x%" PRId64 ") ", m_data.GetSLEB128(&offset));
203       break; // 0x11 1 SLEB128 constant
204     case DW_OP_dup:
205       s->PutCString("DW_OP_dup");
206       break; // 0x12
207     case DW_OP_drop:
208       s->PutCString("DW_OP_drop");
209       break; // 0x13
210     case DW_OP_over:
211       s->PutCString("DW_OP_over");
212       break; // 0x14
213     case DW_OP_pick:
214       s->Printf("DW_OP_pick(0x%2.2x) ", m_data.GetU8(&offset));
215       break; // 0x15 1 1-byte stack index
216     case DW_OP_swap:
217       s->PutCString("DW_OP_swap");
218       break; // 0x16
219     case DW_OP_rot:
220       s->PutCString("DW_OP_rot");
221       break; // 0x17
222     case DW_OP_xderef:
223       s->PutCString("DW_OP_xderef");
224       break; // 0x18
225     case DW_OP_abs:
226       s->PutCString("DW_OP_abs");
227       break; // 0x19
228     case DW_OP_and:
229       s->PutCString("DW_OP_and");
230       break; // 0x1a
231     case DW_OP_div:
232       s->PutCString("DW_OP_div");
233       break; // 0x1b
234     case DW_OP_minus:
235       s->PutCString("DW_OP_minus");
236       break; // 0x1c
237     case DW_OP_mod:
238       s->PutCString("DW_OP_mod");
239       break; // 0x1d
240     case DW_OP_mul:
241       s->PutCString("DW_OP_mul");
242       break; // 0x1e
243     case DW_OP_neg:
244       s->PutCString("DW_OP_neg");
245       break; // 0x1f
246     case DW_OP_not:
247       s->PutCString("DW_OP_not");
248       break; // 0x20
249     case DW_OP_or:
250       s->PutCString("DW_OP_or");
251       break; // 0x21
252     case DW_OP_plus:
253       s->PutCString("DW_OP_plus");
254       break;                // 0x22
255     case DW_OP_plus_uconst: // 0x23 1 ULEB128 addend
256       s->Printf("DW_OP_plus_uconst(0x%" PRIx64 ") ",
257                 m_data.GetULEB128(&offset));
258       break;
259 
260     case DW_OP_shl:
261       s->PutCString("DW_OP_shl");
262       break; // 0x24
263     case DW_OP_shr:
264       s->PutCString("DW_OP_shr");
265       break; // 0x25
266     case DW_OP_shra:
267       s->PutCString("DW_OP_shra");
268       break; // 0x26
269     case DW_OP_xor:
270       s->PutCString("DW_OP_xor");
271       break; // 0x27
272     case DW_OP_skip:
273       s->Printf("DW_OP_skip(0x%4.4x)", m_data.GetU16(&offset));
274       break; // 0x2f 1 signed 2-byte constant
275     case DW_OP_bra:
276       s->Printf("DW_OP_bra(0x%4.4x)", m_data.GetU16(&offset));
277       break; // 0x28 1 signed 2-byte constant
278     case DW_OP_eq:
279       s->PutCString("DW_OP_eq");
280       break; // 0x29
281     case DW_OP_ge:
282       s->PutCString("DW_OP_ge");
283       break; // 0x2a
284     case DW_OP_gt:
285       s->PutCString("DW_OP_gt");
286       break; // 0x2b
287     case DW_OP_le:
288       s->PutCString("DW_OP_le");
289       break; // 0x2c
290     case DW_OP_lt:
291       s->PutCString("DW_OP_lt");
292       break; // 0x2d
293     case DW_OP_ne:
294       s->PutCString("DW_OP_ne");
295       break; // 0x2e
296 
297     case DW_OP_lit0:  // 0x30
298     case DW_OP_lit1:  // 0x31
299     case DW_OP_lit2:  // 0x32
300     case DW_OP_lit3:  // 0x33
301     case DW_OP_lit4:  // 0x34
302     case DW_OP_lit5:  // 0x35
303     case DW_OP_lit6:  // 0x36
304     case DW_OP_lit7:  // 0x37
305     case DW_OP_lit8:  // 0x38
306     case DW_OP_lit9:  // 0x39
307     case DW_OP_lit10: // 0x3A
308     case DW_OP_lit11: // 0x3B
309     case DW_OP_lit12: // 0x3C
310     case DW_OP_lit13: // 0x3D
311     case DW_OP_lit14: // 0x3E
312     case DW_OP_lit15: // 0x3F
313     case DW_OP_lit16: // 0x40
314     case DW_OP_lit17: // 0x41
315     case DW_OP_lit18: // 0x42
316     case DW_OP_lit19: // 0x43
317     case DW_OP_lit20: // 0x44
318     case DW_OP_lit21: // 0x45
319     case DW_OP_lit22: // 0x46
320     case DW_OP_lit23: // 0x47
321     case DW_OP_lit24: // 0x48
322     case DW_OP_lit25: // 0x49
323     case DW_OP_lit26: // 0x4A
324     case DW_OP_lit27: // 0x4B
325     case DW_OP_lit28: // 0x4C
326     case DW_OP_lit29: // 0x4D
327     case DW_OP_lit30: // 0x4E
328     case DW_OP_lit31:
329       s->Printf("DW_OP_lit%i", op - DW_OP_lit0);
330       break; // 0x4f
331 
332     case DW_OP_reg0:  // 0x50
333     case DW_OP_reg1:  // 0x51
334     case DW_OP_reg2:  // 0x52
335     case DW_OP_reg3:  // 0x53
336     case DW_OP_reg4:  // 0x54
337     case DW_OP_reg5:  // 0x55
338     case DW_OP_reg6:  // 0x56
339     case DW_OP_reg7:  // 0x57
340     case DW_OP_reg8:  // 0x58
341     case DW_OP_reg9:  // 0x59
342     case DW_OP_reg10: // 0x5A
343     case DW_OP_reg11: // 0x5B
344     case DW_OP_reg12: // 0x5C
345     case DW_OP_reg13: // 0x5D
346     case DW_OP_reg14: // 0x5E
347     case DW_OP_reg15: // 0x5F
348     case DW_OP_reg16: // 0x60
349     case DW_OP_reg17: // 0x61
350     case DW_OP_reg18: // 0x62
351     case DW_OP_reg19: // 0x63
352     case DW_OP_reg20: // 0x64
353     case DW_OP_reg21: // 0x65
354     case DW_OP_reg22: // 0x66
355     case DW_OP_reg23: // 0x67
356     case DW_OP_reg24: // 0x68
357     case DW_OP_reg25: // 0x69
358     case DW_OP_reg26: // 0x6A
359     case DW_OP_reg27: // 0x6B
360     case DW_OP_reg28: // 0x6C
361     case DW_OP_reg29: // 0x6D
362     case DW_OP_reg30: // 0x6E
363     case DW_OP_reg31: // 0x6F
364     {
365       uint32_t reg_num = op - DW_OP_reg0;
366       if (abi) {
367         RegisterInfo reg_info;
368         if (abi->GetRegisterInfoByKind(m_reg_kind, reg_num, reg_info)) {
369           if (reg_info.name) {
370             s->PutCString(reg_info.name);
371             break;
372           } else if (reg_info.alt_name) {
373             s->PutCString(reg_info.alt_name);
374             break;
375           }
376         }
377       }
378       s->Printf("DW_OP_reg%u", reg_num);
379       break;
380     } break;
381 
382     case DW_OP_breg0:
383     case DW_OP_breg1:
384     case DW_OP_breg2:
385     case DW_OP_breg3:
386     case DW_OP_breg4:
387     case DW_OP_breg5:
388     case DW_OP_breg6:
389     case DW_OP_breg7:
390     case DW_OP_breg8:
391     case DW_OP_breg9:
392     case DW_OP_breg10:
393     case DW_OP_breg11:
394     case DW_OP_breg12:
395     case DW_OP_breg13:
396     case DW_OP_breg14:
397     case DW_OP_breg15:
398     case DW_OP_breg16:
399     case DW_OP_breg17:
400     case DW_OP_breg18:
401     case DW_OP_breg19:
402     case DW_OP_breg20:
403     case DW_OP_breg21:
404     case DW_OP_breg22:
405     case DW_OP_breg23:
406     case DW_OP_breg24:
407     case DW_OP_breg25:
408     case DW_OP_breg26:
409     case DW_OP_breg27:
410     case DW_OP_breg28:
411     case DW_OP_breg29:
412     case DW_OP_breg30:
413     case DW_OP_breg31: {
414       uint32_t reg_num = op - DW_OP_breg0;
415       int64_t reg_offset = m_data.GetSLEB128(&offset);
416       if (abi) {
417         RegisterInfo reg_info;
418         if (abi->GetRegisterInfoByKind(m_reg_kind, reg_num, reg_info)) {
419           if (reg_info.name) {
420             s->Printf("[%s%+" PRIi64 "]", reg_info.name, reg_offset);
421             break;
422           } else if (reg_info.alt_name) {
423             s->Printf("[%s%+" PRIi64 "]", reg_info.alt_name, reg_offset);
424             break;
425           }
426         }
427       }
428       s->Printf("DW_OP_breg%i(0x%" PRIx64 ")", reg_num, reg_offset);
429     } break;
430 
431     case DW_OP_regx: // 0x90 1 ULEB128 register
432     {
433       uint32_t reg_num = m_data.GetULEB128(&offset);
434       if (abi) {
435         RegisterInfo reg_info;
436         if (abi->GetRegisterInfoByKind(m_reg_kind, reg_num, reg_info)) {
437           if (reg_info.name) {
438             s->PutCString(reg_info.name);
439             break;
440           } else if (reg_info.alt_name) {
441             s->PutCString(reg_info.alt_name);
442             break;
443           }
444         }
445       }
446       s->Printf("DW_OP_regx(%" PRIu32 ")", reg_num);
447       break;
448     } break;
449     case DW_OP_fbreg: // 0x91 1 SLEB128 offset
450       s->Printf("DW_OP_fbreg(%" PRIi64 ")", m_data.GetSLEB128(&offset));
451       break;
452     case DW_OP_bregx: // 0x92 2 ULEB128 register followed by SLEB128 offset
453     {
454       uint32_t reg_num = m_data.GetULEB128(&offset);
455       int64_t reg_offset = m_data.GetSLEB128(&offset);
456       if (abi) {
457         RegisterInfo reg_info;
458         if (abi->GetRegisterInfoByKind(m_reg_kind, reg_num, reg_info)) {
459           if (reg_info.name) {
460             s->Printf("[%s%+" PRIi64 "]", reg_info.name, reg_offset);
461             break;
462           } else if (reg_info.alt_name) {
463             s->Printf("[%s%+" PRIi64 "]", reg_info.alt_name, reg_offset);
464             break;
465           }
466         }
467       }
468       s->Printf("DW_OP_bregx(reg=%" PRIu32 ",offset=%" PRIi64 ")", reg_num,
469                 reg_offset);
470     } break;
471     case DW_OP_piece: // 0x93 1 ULEB128 size of piece addressed
472       s->Printf("DW_OP_piece(0x%" PRIx64 ")", m_data.GetULEB128(&offset));
473       break;
474     case DW_OP_deref_size: // 0x94 1 1-byte size of data retrieved
475       s->Printf("DW_OP_deref_size(0x%2.2x)", m_data.GetU8(&offset));
476       break;
477     case DW_OP_xderef_size: // 0x95 1 1-byte size of data retrieved
478       s->Printf("DW_OP_xderef_size(0x%2.2x)", m_data.GetU8(&offset));
479       break;
480     case DW_OP_nop:
481       s->PutCString("DW_OP_nop");
482       break; // 0x96
483     case DW_OP_push_object_address:
484       s->PutCString("DW_OP_push_object_address");
485       break;          // 0x97 DWARF3
486     case DW_OP_call2: // 0x98 DWARF3 1 2-byte offset of DIE
487       s->Printf("DW_OP_call2(0x%4.4x)", m_data.GetU16(&offset));
488       break;
489     case DW_OP_call4: // 0x99 DWARF3 1 4-byte offset of DIE
490       s->Printf("DW_OP_call4(0x%8.8x)", m_data.GetU32(&offset));
491       break;
492     case DW_OP_call_ref: // 0x9a DWARF3 1 4- or 8-byte offset of DIE
493       s->Printf("DW_OP_call_ref(0x%8.8" PRIx64 ")", m_data.GetAddress(&offset));
494       break;
495     //      case DW_OP_call_frame_cfa: s << "call_frame_cfa"; break;
496     //      // 0x9c DWARF3
497     //      case DW_OP_bit_piece: // 0x9d DWARF3 2
498     //          s->Printf("DW_OP_bit_piece(0x%x, 0x%x)",
499     //          m_data.GetULEB128(&offset), m_data.GetULEB128(&offset));
500     //          break;
501     //      case DW_OP_lo_user:     s->PutCString("DW_OP_lo_user"); break;
502     //      // 0xe0
503     //      case DW_OP_hi_user:     s->PutCString("DW_OP_hi_user"); break;
504     //      // 0xff
505     //        case DW_OP_APPLE_extern:
506     //            s->Printf("DW_OP_APPLE_extern(%" PRIu64 ")",
507     //            m_data.GetULEB128(&offset));
508     //            break;
509     //        case DW_OP_APPLE_array_ref:
510     //            s->PutCString("DW_OP_APPLE_array_ref");
511     //            break;
512     case DW_OP_form_tls_address:
513       s->PutCString("DW_OP_form_tls_address"); // 0x9b
514       break;
515     case DW_OP_GNU_addr_index: // 0xfb
516       s->Printf("DW_OP_GNU_addr_index(0x%" PRIx64 ")",
517                 m_data.GetULEB128(&offset));
518       break;
519     case DW_OP_GNU_const_index: // 0xfc
520       s->Printf("DW_OP_GNU_const_index(0x%" PRIx64 ")",
521                 m_data.GetULEB128(&offset));
522       break;
523     case DW_OP_GNU_push_tls_address:
524       s->PutCString("DW_OP_GNU_push_tls_address"); // 0xe0
525       break;
526     case DW_OP_APPLE_uninit:
527       s->PutCString("DW_OP_APPLE_uninit"); // 0xF0
528       break;
529       //        case DW_OP_APPLE_assign:        // 0xF1 - pops value off and
530       //        assigns it to second item on stack (2nd item must have
531       //        assignable context)
532       //            s->PutCString("DW_OP_APPLE_assign");
533       //            break;
534       //        case DW_OP_APPLE_address_of:    // 0xF2 - gets the address of
535       //        the top stack item (top item must be a variable, or have
536       //        value_type that is an address already)
537       //            s->PutCString("DW_OP_APPLE_address_of");
538       //            break;
539       //        case DW_OP_APPLE_value_of:      // 0xF3 - pops the value off the
540       //        stack and pushes the value of that object (top item must be a
541       //        variable, or expression local)
542       //            s->PutCString("DW_OP_APPLE_value_of");
543       //            break;
544       //        case DW_OP_APPLE_deref_type:    // 0xF4 - gets the address of
545       //        the top stack item (top item must be a variable, or a clang
546       //        type)
547       //            s->PutCString("DW_OP_APPLE_deref_type");
548       //            break;
549       //        case DW_OP_APPLE_expr_local:    // 0xF5 - ULEB128 expression
550       //        local index
551       //            s->Printf("DW_OP_APPLE_expr_local(%" PRIu64 ")",
552       //            m_data.GetULEB128(&offset));
553       //            break;
554       //        case DW_OP_APPLE_constf:        // 0xF6 - 1 byte float size,
555       //        followed by constant float data
556       //            {
557       //                uint8_t float_length = m_data.GetU8(&offset);
558       //                s->Printf("DW_OP_APPLE_constf(<%u> ", float_length);
559       //                m_data.Dump(s, offset, eFormatHex, float_length, 1,
560       //                UINT32_MAX, DW_INVALID_ADDRESS, 0, 0);
561       //                s->PutChar(')');
562       //                // Consume the float data
563       //                m_data.GetData(&offset, float_length);
564       //            }
565       //            break;
566       //        case DW_OP_APPLE_scalar_cast:
567       //            s->Printf("DW_OP_APPLE_scalar_cast(%s)",
568       //            Scalar::GetValueTypeAsCString
569       //            ((Scalar::Type)m_data.GetU8(&offset)));
570       //            break;
571       //        case DW_OP_APPLE_clang_cast:
572       //            {
573       //                clang::Type *clang_type = (clang::Type
574       //                *)m_data.GetMaxU64(&offset, sizeof(void*));
575       //                s->Printf("DW_OP_APPLE_clang_cast(%p)", clang_type);
576       //            }
577       //            break;
578       //        case DW_OP_APPLE_clear:
579       //            s->PutCString("DW_OP_APPLE_clear");
580       //            break;
581       //        case DW_OP_APPLE_error:         // 0xFF - Stops expression
582       //        evaluation and returns an error (no args)
583       //            s->PutCString("DW_OP_APPLE_error");
584       //            break;
585     }
586   }
587 }
588 
589 void DWARFExpression::SetLocationListSlide(addr_t slide) {
590   m_loclist_slide = slide;
591 }
592 
593 int DWARFExpression::GetRegisterKind() { return m_reg_kind; }
594 
595 void DWARFExpression::SetRegisterKind(RegisterKind reg_kind) {
596   m_reg_kind = reg_kind;
597 }
598 
599 bool DWARFExpression::IsLocationList() const {
600   return m_loclist_slide != LLDB_INVALID_ADDRESS;
601 }
602 
603 void DWARFExpression::GetDescription(Stream *s, lldb::DescriptionLevel level,
604                                      addr_t location_list_base_addr,
605                                      ABI *abi) const {
606   if (IsLocationList()) {
607     // We have a location list
608     lldb::offset_t offset = 0;
609     uint32_t count = 0;
610     addr_t curr_base_addr = location_list_base_addr;
611     while (m_data.ValidOffset(offset)) {
612       addr_t begin_addr_offset = LLDB_INVALID_ADDRESS;
613       addr_t end_addr_offset = LLDB_INVALID_ADDRESS;
614       if (!AddressRangeForLocationListEntry(m_dwarf_cu, m_data, &offset,
615                                             begin_addr_offset, end_addr_offset))
616         break;
617 
618       if (begin_addr_offset == 0 && end_addr_offset == 0)
619         break;
620 
621       if (begin_addr_offset < end_addr_offset) {
622         if (count > 0)
623           s->PutCString(", ");
624         VMRange addr_range(curr_base_addr + begin_addr_offset,
625                            curr_base_addr + end_addr_offset);
626         addr_range.Dump(s, 0, 8);
627         s->PutChar('{');
628         lldb::offset_t location_length = m_data.GetU16(&offset);
629         DumpLocation(s, offset, location_length, level, abi);
630         s->PutChar('}');
631         offset += location_length;
632       } else {
633         if ((m_data.GetAddressByteSize() == 4 &&
634              (begin_addr_offset == UINT32_MAX)) ||
635             (m_data.GetAddressByteSize() == 8 &&
636              (begin_addr_offset == UINT64_MAX))) {
637           curr_base_addr = end_addr_offset + location_list_base_addr;
638           // We have a new base address
639           if (count > 0)
640             s->PutCString(", ");
641           *s << "base_addr = " << end_addr_offset;
642         }
643       }
644 
645       count++;
646     }
647   } else {
648     // We have a normal location that contains DW_OP location opcodes
649     DumpLocation(s, 0, m_data.GetByteSize(), level, abi);
650   }
651 }
652 
653 static bool ReadRegisterValueAsScalar(RegisterContext *reg_ctx,
654                                       lldb::RegisterKind reg_kind,
655                                       uint32_t reg_num, Status *error_ptr,
656                                       Value &value) {
657   if (reg_ctx == NULL) {
658     if (error_ptr)
659       error_ptr->SetErrorStringWithFormat("No register context in frame.\n");
660   } else {
661     uint32_t native_reg =
662         reg_ctx->ConvertRegisterKindToRegisterNumber(reg_kind, reg_num);
663     if (native_reg == LLDB_INVALID_REGNUM) {
664       if (error_ptr)
665         error_ptr->SetErrorStringWithFormat("Unable to convert register "
666                                             "kind=%u reg_num=%u to a native "
667                                             "register number.\n",
668                                             reg_kind, reg_num);
669     } else {
670       const RegisterInfo *reg_info =
671           reg_ctx->GetRegisterInfoAtIndex(native_reg);
672       RegisterValue reg_value;
673       if (reg_ctx->ReadRegister(reg_info, reg_value)) {
674         if (reg_value.GetScalarValue(value.GetScalar())) {
675           value.SetValueType(Value::eValueTypeScalar);
676           value.SetContext(Value::eContextTypeRegisterInfo,
677                            const_cast<RegisterInfo *>(reg_info));
678           if (error_ptr)
679             error_ptr->Clear();
680           return true;
681         } else {
682           // If we get this error, then we need to implement a value buffer in
683           // the dwarf expression evaluation function...
684           if (error_ptr)
685             error_ptr->SetErrorStringWithFormat(
686                 "register %s can't be converted to a scalar value",
687                 reg_info->name);
688         }
689       } else {
690         if (error_ptr)
691           error_ptr->SetErrorStringWithFormat("register %s is not available",
692                                               reg_info->name);
693       }
694     }
695   }
696   return false;
697 }
698 
699 // bool
700 // DWARFExpression::LocationListContainsLoadAddress (Process* process, const
701 // Address &addr) const
702 //{
703 //    return LocationListContainsLoadAddress(process,
704 //    addr.GetLoadAddress(process));
705 //}
706 //
707 // bool
708 // DWARFExpression::LocationListContainsLoadAddress (Process* process, addr_t
709 // load_addr) const
710 //{
711 //    if (load_addr == LLDB_INVALID_ADDRESS)
712 //        return false;
713 //
714 //    if (IsLocationList())
715 //    {
716 //        lldb::offset_t offset = 0;
717 //
718 //        addr_t loc_list_base_addr = m_loclist_slide.GetLoadAddress(process);
719 //
720 //        if (loc_list_base_addr == LLDB_INVALID_ADDRESS)
721 //            return false;
722 //
723 //        while (m_data.ValidOffset(offset))
724 //        {
725 //            // We need to figure out what the value is for the location.
726 //            addr_t lo_pc = m_data.GetAddress(&offset);
727 //            addr_t hi_pc = m_data.GetAddress(&offset);
728 //            if (lo_pc == 0 && hi_pc == 0)
729 //                break;
730 //            else
731 //            {
732 //                lo_pc += loc_list_base_addr;
733 //                hi_pc += loc_list_base_addr;
734 //
735 //                if (lo_pc <= load_addr && load_addr < hi_pc)
736 //                    return true;
737 //
738 //                offset += m_data.GetU16(&offset);
739 //            }
740 //        }
741 //    }
742 //    return false;
743 //}
744 
745 static offset_t GetOpcodeDataSize(const DataExtractor &data,
746                                   const lldb::offset_t data_offset,
747                                   const uint8_t op) {
748   lldb::offset_t offset = data_offset;
749   switch (op) {
750   case DW_OP_addr:
751   case DW_OP_call_ref: // 0x9a 1 address sized offset of DIE (DWARF3)
752     return data.GetAddressByteSize();
753 
754   // Opcodes with no arguments
755   case DW_OP_deref:                // 0x06
756   case DW_OP_dup:                  // 0x12
757   case DW_OP_drop:                 // 0x13
758   case DW_OP_over:                 // 0x14
759   case DW_OP_swap:                 // 0x16
760   case DW_OP_rot:                  // 0x17
761   case DW_OP_xderef:               // 0x18
762   case DW_OP_abs:                  // 0x19
763   case DW_OP_and:                  // 0x1a
764   case DW_OP_div:                  // 0x1b
765   case DW_OP_minus:                // 0x1c
766   case DW_OP_mod:                  // 0x1d
767   case DW_OP_mul:                  // 0x1e
768   case DW_OP_neg:                  // 0x1f
769   case DW_OP_not:                  // 0x20
770   case DW_OP_or:                   // 0x21
771   case DW_OP_plus:                 // 0x22
772   case DW_OP_shl:                  // 0x24
773   case DW_OP_shr:                  // 0x25
774   case DW_OP_shra:                 // 0x26
775   case DW_OP_xor:                  // 0x27
776   case DW_OP_eq:                   // 0x29
777   case DW_OP_ge:                   // 0x2a
778   case DW_OP_gt:                   // 0x2b
779   case DW_OP_le:                   // 0x2c
780   case DW_OP_lt:                   // 0x2d
781   case DW_OP_ne:                   // 0x2e
782   case DW_OP_lit0:                 // 0x30
783   case DW_OP_lit1:                 // 0x31
784   case DW_OP_lit2:                 // 0x32
785   case DW_OP_lit3:                 // 0x33
786   case DW_OP_lit4:                 // 0x34
787   case DW_OP_lit5:                 // 0x35
788   case DW_OP_lit6:                 // 0x36
789   case DW_OP_lit7:                 // 0x37
790   case DW_OP_lit8:                 // 0x38
791   case DW_OP_lit9:                 // 0x39
792   case DW_OP_lit10:                // 0x3A
793   case DW_OP_lit11:                // 0x3B
794   case DW_OP_lit12:                // 0x3C
795   case DW_OP_lit13:                // 0x3D
796   case DW_OP_lit14:                // 0x3E
797   case DW_OP_lit15:                // 0x3F
798   case DW_OP_lit16:                // 0x40
799   case DW_OP_lit17:                // 0x41
800   case DW_OP_lit18:                // 0x42
801   case DW_OP_lit19:                // 0x43
802   case DW_OP_lit20:                // 0x44
803   case DW_OP_lit21:                // 0x45
804   case DW_OP_lit22:                // 0x46
805   case DW_OP_lit23:                // 0x47
806   case DW_OP_lit24:                // 0x48
807   case DW_OP_lit25:                // 0x49
808   case DW_OP_lit26:                // 0x4A
809   case DW_OP_lit27:                // 0x4B
810   case DW_OP_lit28:                // 0x4C
811   case DW_OP_lit29:                // 0x4D
812   case DW_OP_lit30:                // 0x4E
813   case DW_OP_lit31:                // 0x4f
814   case DW_OP_reg0:                 // 0x50
815   case DW_OP_reg1:                 // 0x51
816   case DW_OP_reg2:                 // 0x52
817   case DW_OP_reg3:                 // 0x53
818   case DW_OP_reg4:                 // 0x54
819   case DW_OP_reg5:                 // 0x55
820   case DW_OP_reg6:                 // 0x56
821   case DW_OP_reg7:                 // 0x57
822   case DW_OP_reg8:                 // 0x58
823   case DW_OP_reg9:                 // 0x59
824   case DW_OP_reg10:                // 0x5A
825   case DW_OP_reg11:                // 0x5B
826   case DW_OP_reg12:                // 0x5C
827   case DW_OP_reg13:                // 0x5D
828   case DW_OP_reg14:                // 0x5E
829   case DW_OP_reg15:                // 0x5F
830   case DW_OP_reg16:                // 0x60
831   case DW_OP_reg17:                // 0x61
832   case DW_OP_reg18:                // 0x62
833   case DW_OP_reg19:                // 0x63
834   case DW_OP_reg20:                // 0x64
835   case DW_OP_reg21:                // 0x65
836   case DW_OP_reg22:                // 0x66
837   case DW_OP_reg23:                // 0x67
838   case DW_OP_reg24:                // 0x68
839   case DW_OP_reg25:                // 0x69
840   case DW_OP_reg26:                // 0x6A
841   case DW_OP_reg27:                // 0x6B
842   case DW_OP_reg28:                // 0x6C
843   case DW_OP_reg29:                // 0x6D
844   case DW_OP_reg30:                // 0x6E
845   case DW_OP_reg31:                // 0x6F
846   case DW_OP_nop:                  // 0x96
847   case DW_OP_push_object_address:  // 0x97 DWARF3
848   case DW_OP_form_tls_address:     // 0x9b DWARF3
849   case DW_OP_call_frame_cfa:       // 0x9c DWARF3
850   case DW_OP_stack_value:          // 0x9f DWARF4
851   case DW_OP_GNU_push_tls_address: // 0xe0 GNU extension
852     return 0;
853 
854   // Opcodes with a single 1 byte arguments
855   case DW_OP_const1u:     // 0x08 1 1-byte constant
856   case DW_OP_const1s:     // 0x09 1 1-byte constant
857   case DW_OP_pick:        // 0x15 1 1-byte stack index
858   case DW_OP_deref_size:  // 0x94 1 1-byte size of data retrieved
859   case DW_OP_xderef_size: // 0x95 1 1-byte size of data retrieved
860     return 1;
861 
862   // Opcodes with a single 2 byte arguments
863   case DW_OP_const2u: // 0x0a 1 2-byte constant
864   case DW_OP_const2s: // 0x0b 1 2-byte constant
865   case DW_OP_skip:    // 0x2f 1 signed 2-byte constant
866   case DW_OP_bra:     // 0x28 1 signed 2-byte constant
867   case DW_OP_call2:   // 0x98 1 2-byte offset of DIE (DWARF3)
868     return 2;
869 
870   // Opcodes with a single 4 byte arguments
871   case DW_OP_const4u: // 0x0c 1 4-byte constant
872   case DW_OP_const4s: // 0x0d 1 4-byte constant
873   case DW_OP_call4:   // 0x99 1 4-byte offset of DIE (DWARF3)
874     return 4;
875 
876   // Opcodes with a single 8 byte arguments
877   case DW_OP_const8u: // 0x0e 1 8-byte constant
878   case DW_OP_const8s: // 0x0f 1 8-byte constant
879     return 8;
880 
881   // All opcodes that have a single ULEB (signed or unsigned) argument
882   case DW_OP_constu:          // 0x10 1 ULEB128 constant
883   case DW_OP_consts:          // 0x11 1 SLEB128 constant
884   case DW_OP_plus_uconst:     // 0x23 1 ULEB128 addend
885   case DW_OP_breg0:           // 0x70 1 ULEB128 register
886   case DW_OP_breg1:           // 0x71 1 ULEB128 register
887   case DW_OP_breg2:           // 0x72 1 ULEB128 register
888   case DW_OP_breg3:           // 0x73 1 ULEB128 register
889   case DW_OP_breg4:           // 0x74 1 ULEB128 register
890   case DW_OP_breg5:           // 0x75 1 ULEB128 register
891   case DW_OP_breg6:           // 0x76 1 ULEB128 register
892   case DW_OP_breg7:           // 0x77 1 ULEB128 register
893   case DW_OP_breg8:           // 0x78 1 ULEB128 register
894   case DW_OP_breg9:           // 0x79 1 ULEB128 register
895   case DW_OP_breg10:          // 0x7a 1 ULEB128 register
896   case DW_OP_breg11:          // 0x7b 1 ULEB128 register
897   case DW_OP_breg12:          // 0x7c 1 ULEB128 register
898   case DW_OP_breg13:          // 0x7d 1 ULEB128 register
899   case DW_OP_breg14:          // 0x7e 1 ULEB128 register
900   case DW_OP_breg15:          // 0x7f 1 ULEB128 register
901   case DW_OP_breg16:          // 0x80 1 ULEB128 register
902   case DW_OP_breg17:          // 0x81 1 ULEB128 register
903   case DW_OP_breg18:          // 0x82 1 ULEB128 register
904   case DW_OP_breg19:          // 0x83 1 ULEB128 register
905   case DW_OP_breg20:          // 0x84 1 ULEB128 register
906   case DW_OP_breg21:          // 0x85 1 ULEB128 register
907   case DW_OP_breg22:          // 0x86 1 ULEB128 register
908   case DW_OP_breg23:          // 0x87 1 ULEB128 register
909   case DW_OP_breg24:          // 0x88 1 ULEB128 register
910   case DW_OP_breg25:          // 0x89 1 ULEB128 register
911   case DW_OP_breg26:          // 0x8a 1 ULEB128 register
912   case DW_OP_breg27:          // 0x8b 1 ULEB128 register
913   case DW_OP_breg28:          // 0x8c 1 ULEB128 register
914   case DW_OP_breg29:          // 0x8d 1 ULEB128 register
915   case DW_OP_breg30:          // 0x8e 1 ULEB128 register
916   case DW_OP_breg31:          // 0x8f 1 ULEB128 register
917   case DW_OP_regx:            // 0x90 1 ULEB128 register
918   case DW_OP_fbreg:           // 0x91 1 SLEB128 offset
919   case DW_OP_piece:           // 0x93 1 ULEB128 size of piece addressed
920   case DW_OP_GNU_addr_index:  // 0xfb 1 ULEB128 index
921   case DW_OP_GNU_const_index: // 0xfc 1 ULEB128 index
922     data.Skip_LEB128(&offset);
923     return offset - data_offset;
924 
925   // All opcodes that have a 2 ULEB (signed or unsigned) arguments
926   case DW_OP_bregx:     // 0x92 2 ULEB128 register followed by SLEB128 offset
927   case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3);
928     data.Skip_LEB128(&offset);
929     data.Skip_LEB128(&offset);
930     return offset - data_offset;
931 
932   case DW_OP_implicit_value: // 0x9e ULEB128 size followed by block of that size
933                              // (DWARF4)
934   {
935     uint64_t block_len = data.Skip_LEB128(&offset);
936     offset += block_len;
937     return offset - data_offset;
938   }
939 
940   default:
941     break;
942   }
943   return LLDB_INVALID_OFFSET;
944 }
945 
946 lldb::addr_t DWARFExpression::GetLocation_DW_OP_addr(uint32_t op_addr_idx,
947                                                      bool &error) const {
948   error = false;
949   if (IsLocationList())
950     return LLDB_INVALID_ADDRESS;
951   lldb::offset_t offset = 0;
952   uint32_t curr_op_addr_idx = 0;
953   while (m_data.ValidOffset(offset)) {
954     const uint8_t op = m_data.GetU8(&offset);
955 
956     if (op == DW_OP_addr) {
957       const lldb::addr_t op_file_addr = m_data.GetAddress(&offset);
958       if (curr_op_addr_idx == op_addr_idx)
959         return op_file_addr;
960       else
961         ++curr_op_addr_idx;
962     } else if (op == DW_OP_GNU_addr_index) {
963       uint64_t index = m_data.GetULEB128(&offset);
964       if (curr_op_addr_idx == op_addr_idx) {
965         if (!m_dwarf_cu) {
966           error = true;
967           break;
968         }
969 
970         return ReadAddressFromDebugAddrSection(m_dwarf_cu, index);
971       } else
972         ++curr_op_addr_idx;
973     } else {
974       const offset_t op_arg_size = GetOpcodeDataSize(m_data, offset, op);
975       if (op_arg_size == LLDB_INVALID_OFFSET) {
976         error = true;
977         break;
978       }
979       offset += op_arg_size;
980     }
981   }
982   return LLDB_INVALID_ADDRESS;
983 }
984 
985 bool DWARFExpression::Update_DW_OP_addr(lldb::addr_t file_addr) {
986   if (IsLocationList())
987     return false;
988   lldb::offset_t offset = 0;
989   while (m_data.ValidOffset(offset)) {
990     const uint8_t op = m_data.GetU8(&offset);
991 
992     if (op == DW_OP_addr) {
993       const uint32_t addr_byte_size = m_data.GetAddressByteSize();
994       // We have to make a copy of the data as we don't know if this data is
995       // from a read only memory mapped buffer, so we duplicate all of the data
996       // first, then modify it, and if all goes well, we then replace the data
997       // for this expression
998 
999       // So first we copy the data into a heap buffer
1000       std::unique_ptr<DataBufferHeap> head_data_ap(
1001           new DataBufferHeap(m_data.GetDataStart(), m_data.GetByteSize()));
1002 
1003       // Make en encoder so we can write the address into the buffer using the
1004       // correct byte order (endianness)
1005       DataEncoder encoder(head_data_ap->GetBytes(), head_data_ap->GetByteSize(),
1006                           m_data.GetByteOrder(), addr_byte_size);
1007 
1008       // Replace the address in the new buffer
1009       if (encoder.PutMaxU64(offset, addr_byte_size, file_addr) == UINT32_MAX)
1010         return false;
1011 
1012       // All went well, so now we can reset the data using a shared pointer to
1013       // the heap data so "m_data" will now correctly manage the heap data.
1014       m_data.SetData(DataBufferSP(head_data_ap.release()));
1015       return true;
1016     } else {
1017       const offset_t op_arg_size = GetOpcodeDataSize(m_data, offset, op);
1018       if (op_arg_size == LLDB_INVALID_OFFSET)
1019         break;
1020       offset += op_arg_size;
1021     }
1022   }
1023   return false;
1024 }
1025 
1026 bool DWARFExpression::ContainsThreadLocalStorage() const {
1027   // We are assuming for now that any thread local variable will not have a
1028   // location list. This has been true for all thread local variables we have
1029   // seen so far produced by any compiler.
1030   if (IsLocationList())
1031     return false;
1032   lldb::offset_t offset = 0;
1033   while (m_data.ValidOffset(offset)) {
1034     const uint8_t op = m_data.GetU8(&offset);
1035 
1036     if (op == DW_OP_form_tls_address || op == DW_OP_GNU_push_tls_address)
1037       return true;
1038     const offset_t op_arg_size = GetOpcodeDataSize(m_data, offset, op);
1039     if (op_arg_size == LLDB_INVALID_OFFSET)
1040       return false;
1041     else
1042       offset += op_arg_size;
1043   }
1044   return false;
1045 }
1046 bool DWARFExpression::LinkThreadLocalStorage(
1047     lldb::ModuleSP new_module_sp,
1048     std::function<lldb::addr_t(lldb::addr_t file_addr)> const
1049         &link_address_callback) {
1050   // We are assuming for now that any thread local variable will not have a
1051   // location list. This has been true for all thread local variables we have
1052   // seen so far produced by any compiler.
1053   if (IsLocationList())
1054     return false;
1055 
1056   const uint32_t addr_byte_size = m_data.GetAddressByteSize();
1057   // We have to make a copy of the data as we don't know if this data is from a
1058   // read only memory mapped buffer, so we duplicate all of the data first,
1059   // then modify it, and if all goes well, we then replace the data for this
1060   // expression
1061 
1062   // So first we copy the data into a heap buffer
1063   std::shared_ptr<DataBufferHeap> heap_data_sp(
1064       new DataBufferHeap(m_data.GetDataStart(), m_data.GetByteSize()));
1065 
1066   // Make en encoder so we can write the address into the buffer using the
1067   // correct byte order (endianness)
1068   DataEncoder encoder(heap_data_sp->GetBytes(), heap_data_sp->GetByteSize(),
1069                       m_data.GetByteOrder(), addr_byte_size);
1070 
1071   lldb::offset_t offset = 0;
1072   lldb::offset_t const_offset = 0;
1073   lldb::addr_t const_value = 0;
1074   size_t const_byte_size = 0;
1075   while (m_data.ValidOffset(offset)) {
1076     const uint8_t op = m_data.GetU8(&offset);
1077 
1078     bool decoded_data = false;
1079     switch (op) {
1080     case DW_OP_const4u:
1081       // Remember the const offset in case we later have a
1082       // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address
1083       const_offset = offset;
1084       const_value = m_data.GetU32(&offset);
1085       decoded_data = true;
1086       const_byte_size = 4;
1087       break;
1088 
1089     case DW_OP_const8u:
1090       // Remember the const offset in case we later have a
1091       // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address
1092       const_offset = offset;
1093       const_value = m_data.GetU64(&offset);
1094       decoded_data = true;
1095       const_byte_size = 8;
1096       break;
1097 
1098     case DW_OP_form_tls_address:
1099     case DW_OP_GNU_push_tls_address:
1100       // DW_OP_form_tls_address and DW_OP_GNU_push_tls_address must be preceded
1101       // by a file address on the stack. We assume that DW_OP_const4u or
1102       // DW_OP_const8u is used for these values, and we check that the last
1103       // opcode we got before either of these was DW_OP_const4u or
1104       // DW_OP_const8u. If so, then we can link the value accodingly. For
1105       // Darwin, the value in the DW_OP_const4u or DW_OP_const8u is the file
1106       // address of a structure that contains a function pointer, the pthread
1107       // key and the offset into the data pointed to by the pthread key. So we
1108       // must link this address and also set the module of this expression to
1109       // the new_module_sp so we can resolve the file address correctly
1110       if (const_byte_size > 0) {
1111         lldb::addr_t linked_file_addr = link_address_callback(const_value);
1112         if (linked_file_addr == LLDB_INVALID_ADDRESS)
1113           return false;
1114         // Replace the address in the new buffer
1115         if (encoder.PutMaxU64(const_offset, const_byte_size,
1116                               linked_file_addr) == UINT32_MAX)
1117           return false;
1118       }
1119       break;
1120 
1121     default:
1122       const_offset = 0;
1123       const_value = 0;
1124       const_byte_size = 0;
1125       break;
1126     }
1127 
1128     if (!decoded_data) {
1129       const offset_t op_arg_size = GetOpcodeDataSize(m_data, offset, op);
1130       if (op_arg_size == LLDB_INVALID_OFFSET)
1131         return false;
1132       else
1133         offset += op_arg_size;
1134     }
1135   }
1136 
1137   // If we linked the TLS address correctly, update the module so that when the
1138   // expression is evaluated it can resolve the file address to a load address
1139   // and read the
1140   // TLS data
1141   m_module_wp = new_module_sp;
1142   m_data.SetData(heap_data_sp);
1143   return true;
1144 }
1145 
1146 bool DWARFExpression::LocationListContainsAddress(
1147     lldb::addr_t loclist_base_addr, lldb::addr_t addr) const {
1148   if (addr == LLDB_INVALID_ADDRESS)
1149     return false;
1150 
1151   if (IsLocationList()) {
1152     lldb::offset_t offset = 0;
1153 
1154     if (loclist_base_addr == LLDB_INVALID_ADDRESS)
1155       return false;
1156 
1157     while (m_data.ValidOffset(offset)) {
1158       // We need to figure out what the value is for the location.
1159       addr_t lo_pc = LLDB_INVALID_ADDRESS;
1160       addr_t hi_pc = LLDB_INVALID_ADDRESS;
1161       if (!AddressRangeForLocationListEntry(m_dwarf_cu, m_data, &offset, lo_pc,
1162                                             hi_pc))
1163         break;
1164 
1165       if (lo_pc == 0 && hi_pc == 0)
1166         break;
1167 
1168       lo_pc += loclist_base_addr - m_loclist_slide;
1169       hi_pc += loclist_base_addr - m_loclist_slide;
1170 
1171       if (lo_pc <= addr && addr < hi_pc)
1172         return true;
1173 
1174       offset += m_data.GetU16(&offset);
1175     }
1176   }
1177   return false;
1178 }
1179 
1180 bool DWARFExpression::GetLocation(addr_t base_addr, addr_t pc,
1181                                   lldb::offset_t &offset,
1182                                   lldb::offset_t &length) {
1183   offset = 0;
1184   if (!IsLocationList()) {
1185     length = m_data.GetByteSize();
1186     return true;
1187   }
1188 
1189   if (base_addr != LLDB_INVALID_ADDRESS && pc != LLDB_INVALID_ADDRESS) {
1190     addr_t curr_base_addr = base_addr;
1191 
1192     while (m_data.ValidOffset(offset)) {
1193       // We need to figure out what the value is for the location.
1194       addr_t lo_pc = LLDB_INVALID_ADDRESS;
1195       addr_t hi_pc = LLDB_INVALID_ADDRESS;
1196       if (!AddressRangeForLocationListEntry(m_dwarf_cu, m_data, &offset, lo_pc,
1197                                             hi_pc))
1198         break;
1199 
1200       if (lo_pc == 0 && hi_pc == 0)
1201         break;
1202 
1203       lo_pc += curr_base_addr - m_loclist_slide;
1204       hi_pc += curr_base_addr - m_loclist_slide;
1205 
1206       length = m_data.GetU16(&offset);
1207 
1208       if (length > 0 && lo_pc <= pc && pc < hi_pc)
1209         return true;
1210 
1211       offset += length;
1212     }
1213   }
1214   offset = LLDB_INVALID_OFFSET;
1215   length = 0;
1216   return false;
1217 }
1218 
1219 bool DWARFExpression::DumpLocationForAddress(Stream *s,
1220                                              lldb::DescriptionLevel level,
1221                                              addr_t base_addr, addr_t address,
1222                                              ABI *abi) {
1223   lldb::offset_t offset = 0;
1224   lldb::offset_t length = 0;
1225 
1226   if (GetLocation(base_addr, address, offset, length)) {
1227     if (length > 0) {
1228       DumpLocation(s, offset, length, level, abi);
1229       return true;
1230     }
1231   }
1232   return false;
1233 }
1234 
1235 bool DWARFExpression::Evaluate(ExecutionContextScope *exe_scope,
1236                                lldb::addr_t loclist_base_load_addr,
1237                                const Value *initial_value_ptr,
1238                                const Value *object_address_ptr, Value &result,
1239                                Status *error_ptr) const {
1240   ExecutionContext exe_ctx(exe_scope);
1241   return Evaluate(&exe_ctx, nullptr, loclist_base_load_addr, initial_value_ptr,
1242                   object_address_ptr, result, error_ptr);
1243 }
1244 
1245 bool DWARFExpression::Evaluate(ExecutionContext *exe_ctx,
1246                                RegisterContext *reg_ctx,
1247                                lldb::addr_t loclist_base_load_addr,
1248                                const Value *initial_value_ptr,
1249                                const Value *object_address_ptr, Value &result,
1250                                Status *error_ptr) const {
1251   ModuleSP module_sp = m_module_wp.lock();
1252 
1253   if (IsLocationList()) {
1254     lldb::offset_t offset = 0;
1255     addr_t pc;
1256     StackFrame *frame = NULL;
1257     if (reg_ctx)
1258       pc = reg_ctx->GetPC();
1259     else {
1260       frame = exe_ctx->GetFramePtr();
1261       if (!frame)
1262         return false;
1263       RegisterContextSP reg_ctx_sp = frame->GetRegisterContext();
1264       if (!reg_ctx_sp)
1265         return false;
1266       pc = reg_ctx_sp->GetPC();
1267     }
1268 
1269     if (loclist_base_load_addr != LLDB_INVALID_ADDRESS) {
1270       if (pc == LLDB_INVALID_ADDRESS) {
1271         if (error_ptr)
1272           error_ptr->SetErrorString("Invalid PC in frame.");
1273         return false;
1274       }
1275 
1276       addr_t curr_loclist_base_load_addr = loclist_base_load_addr;
1277 
1278       while (m_data.ValidOffset(offset)) {
1279         // We need to figure out what the value is for the location.
1280         addr_t lo_pc = LLDB_INVALID_ADDRESS;
1281         addr_t hi_pc = LLDB_INVALID_ADDRESS;
1282         if (!AddressRangeForLocationListEntry(m_dwarf_cu, m_data, &offset,
1283                                               lo_pc, hi_pc))
1284           break;
1285 
1286         if (lo_pc == 0 && hi_pc == 0)
1287           break;
1288 
1289         lo_pc += curr_loclist_base_load_addr - m_loclist_slide;
1290         hi_pc += curr_loclist_base_load_addr - m_loclist_slide;
1291 
1292         uint16_t length = m_data.GetU16(&offset);
1293 
1294         if (length > 0 && lo_pc <= pc && pc < hi_pc) {
1295           return DWARFExpression::Evaluate(
1296               exe_ctx, reg_ctx, module_sp, m_data, m_dwarf_cu, offset, length,
1297               m_reg_kind, initial_value_ptr, object_address_ptr, result,
1298               error_ptr);
1299         }
1300         offset += length;
1301       }
1302     }
1303     if (error_ptr)
1304       error_ptr->SetErrorString("variable not available");
1305     return false;
1306   }
1307 
1308   // Not a location list, just a single expression.
1309   return DWARFExpression::Evaluate(
1310       exe_ctx, reg_ctx, module_sp, m_data, m_dwarf_cu, 0, m_data.GetByteSize(),
1311       m_reg_kind, initial_value_ptr, object_address_ptr, result, error_ptr);
1312 }
1313 
1314 bool DWARFExpression::Evaluate(
1315     ExecutionContext *exe_ctx, RegisterContext *reg_ctx,
1316     lldb::ModuleSP module_sp, const DataExtractor &opcodes,
1317     DWARFUnit *dwarf_cu, const lldb::offset_t opcodes_offset,
1318     const lldb::offset_t opcodes_length, const lldb::RegisterKind reg_kind,
1319     const Value *initial_value_ptr, const Value *object_address_ptr,
1320     Value &result, Status *error_ptr) {
1321 
1322   if (opcodes_length == 0) {
1323     if (error_ptr)
1324       error_ptr->SetErrorString(
1325           "no location, value may have been optimized out");
1326     return false;
1327   }
1328   std::vector<Value> stack;
1329 
1330   Process *process = NULL;
1331   StackFrame *frame = NULL;
1332 
1333   if (exe_ctx) {
1334     process = exe_ctx->GetProcessPtr();
1335     frame = exe_ctx->GetFramePtr();
1336   }
1337   if (reg_ctx == NULL && frame)
1338     reg_ctx = frame->GetRegisterContext().get();
1339 
1340   if (initial_value_ptr)
1341     stack.push_back(*initial_value_ptr);
1342 
1343   lldb::offset_t offset = opcodes_offset;
1344   const lldb::offset_t end_offset = opcodes_offset + opcodes_length;
1345   Value tmp;
1346   uint32_t reg_num;
1347 
1348   /// Insertion point for evaluating multi-piece expression.
1349   uint64_t op_piece_offset = 0;
1350   Value pieces; // Used for DW_OP_piece
1351 
1352   // Make sure all of the data is available in opcodes.
1353   if (!opcodes.ValidOffsetForDataOfSize(opcodes_offset, opcodes_length)) {
1354     if (error_ptr)
1355       error_ptr->SetErrorString(
1356           "invalid offset and/or length for opcodes buffer.");
1357     return false;
1358   }
1359   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
1360 
1361   while (opcodes.ValidOffset(offset) && offset < end_offset) {
1362     const lldb::offset_t op_offset = offset;
1363     const uint8_t op = opcodes.GetU8(&offset);
1364 
1365     if (log && log->GetVerbose()) {
1366       size_t count = stack.size();
1367       log->Printf("Stack before operation has %" PRIu64 " values:",
1368                   (uint64_t)count);
1369       for (size_t i = 0; i < count; ++i) {
1370         StreamString new_value;
1371         new_value.Printf("[%" PRIu64 "]", (uint64_t)i);
1372         stack[i].Dump(&new_value);
1373         log->Printf("  %s", new_value.GetData());
1374       }
1375       log->Printf("0x%8.8" PRIx64 ": %s", op_offset, DW_OP_value_to_name(op));
1376     }
1377 
1378     switch (op) {
1379     //----------------------------------------------------------------------
1380     // The DW_OP_addr operation has a single operand that encodes a machine
1381     // address and whose size is the size of an address on the target machine.
1382     //----------------------------------------------------------------------
1383     case DW_OP_addr:
1384       stack.push_back(Scalar(opcodes.GetAddress(&offset)));
1385       stack.back().SetValueType(Value::eValueTypeFileAddress);
1386       // Convert the file address to a load address, so subsequent
1387       // DWARF operators can operate on it.
1388       if (frame)
1389         stack.back().ConvertToLoadAddress(module_sp.get(),
1390                                           frame->CalculateTarget().get());
1391       break;
1392 
1393     //----------------------------------------------------------------------
1394     // The DW_OP_addr_sect_offset4 is used for any location expressions in
1395     // shared libraries that have a location like:
1396     //  DW_OP_addr(0x1000)
1397     // If this address resides in a shared library, then this virtual address
1398     // won't make sense when it is evaluated in the context of a running
1399     // process where shared libraries have been slid. To account for this, this
1400     // new address type where we can store the section pointer and a 4 byte
1401     // offset.
1402     //----------------------------------------------------------------------
1403     //      case DW_OP_addr_sect_offset4:
1404     //          {
1405     //              result_type = eResultTypeFileAddress;
1406     //              lldb::Section *sect = (lldb::Section
1407     //              *)opcodes.GetMaxU64(&offset, sizeof(void *));
1408     //              lldb::addr_t sect_offset = opcodes.GetU32(&offset);
1409     //
1410     //              Address so_addr (sect, sect_offset);
1411     //              lldb::addr_t load_addr = so_addr.GetLoadAddress();
1412     //              if (load_addr != LLDB_INVALID_ADDRESS)
1413     //              {
1414     //                  // We successfully resolve a file address to a load
1415     //                  // address.
1416     //                  stack.push_back(load_addr);
1417     //                  break;
1418     //              }
1419     //              else
1420     //              {
1421     //                  // We were able
1422     //                  if (error_ptr)
1423     //                      error_ptr->SetErrorStringWithFormat ("Section %s in
1424     //                      %s is not currently loaded.\n",
1425     //                      sect->GetName().AsCString(),
1426     //                      sect->GetModule()->GetFileSpec().GetFilename().AsCString());
1427     //                  return false;
1428     //              }
1429     //          }
1430     //          break;
1431 
1432     //----------------------------------------------------------------------
1433     // OPCODE: DW_OP_deref
1434     // OPERANDS: none
1435     // DESCRIPTION: Pops the top stack entry and treats it as an address.
1436     // The value retrieved from that address is pushed. The size of the data
1437     // retrieved from the dereferenced address is the size of an address on the
1438     // target machine.
1439     //----------------------------------------------------------------------
1440     case DW_OP_deref: {
1441       if (stack.empty()) {
1442         if (error_ptr)
1443           error_ptr->SetErrorString("Expression stack empty for DW_OP_deref.");
1444         return false;
1445       }
1446       Value::ValueType value_type = stack.back().GetValueType();
1447       switch (value_type) {
1448       case Value::eValueTypeHostAddress: {
1449         void *src = (void *)stack.back().GetScalar().ULongLong();
1450         intptr_t ptr;
1451         ::memcpy(&ptr, src, sizeof(void *));
1452         stack.back().GetScalar() = ptr;
1453         stack.back().ClearContext();
1454       } break;
1455       case Value::eValueTypeLoadAddress:
1456         if (exe_ctx) {
1457           if (process) {
1458             lldb::addr_t pointer_addr =
1459                 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
1460             Status error;
1461             lldb::addr_t pointer_value =
1462                 process->ReadPointerFromMemory(pointer_addr, error);
1463             if (pointer_value != LLDB_INVALID_ADDRESS) {
1464               stack.back().GetScalar() = pointer_value;
1465               stack.back().ClearContext();
1466             } else {
1467               if (error_ptr)
1468                 error_ptr->SetErrorStringWithFormat(
1469                     "Failed to dereference pointer from 0x%" PRIx64
1470                     " for DW_OP_deref: %s\n",
1471                     pointer_addr, error.AsCString());
1472               return false;
1473             }
1474           } else {
1475             if (error_ptr)
1476               error_ptr->SetErrorStringWithFormat(
1477                   "NULL process for DW_OP_deref.\n");
1478             return false;
1479           }
1480         } else {
1481           if (error_ptr)
1482             error_ptr->SetErrorStringWithFormat(
1483                 "NULL execution context for DW_OP_deref.\n");
1484           return false;
1485         }
1486         break;
1487 
1488       default:
1489         break;
1490       }
1491 
1492     } break;
1493 
1494     //----------------------------------------------------------------------
1495     // OPCODE: DW_OP_deref_size
1496     // OPERANDS: 1
1497     //  1 - uint8_t that specifies the size of the data to dereference.
1498     // DESCRIPTION: Behaves like the DW_OP_deref operation: it pops the top
1499     // stack entry and treats it as an address. The value retrieved from that
1500     // address is pushed. In the DW_OP_deref_size operation, however, the size
1501     // in bytes of the data retrieved from the dereferenced address is
1502     // specified by the single operand. This operand is a 1-byte unsigned
1503     // integral constant whose value may not be larger than the size of an
1504     // address on the target machine. The data retrieved is zero extended to
1505     // the size of an address on the target machine before being pushed on the
1506     // expression stack.
1507     //----------------------------------------------------------------------
1508     case DW_OP_deref_size: {
1509       if (stack.empty()) {
1510         if (error_ptr)
1511           error_ptr->SetErrorString(
1512               "Expression stack empty for DW_OP_deref_size.");
1513         return false;
1514       }
1515       uint8_t size = opcodes.GetU8(&offset);
1516       Value::ValueType value_type = stack.back().GetValueType();
1517       switch (value_type) {
1518       case Value::eValueTypeHostAddress: {
1519         void *src = (void *)stack.back().GetScalar().ULongLong();
1520         intptr_t ptr;
1521         ::memcpy(&ptr, src, sizeof(void *));
1522         // I can't decide whether the size operand should apply to the bytes in
1523         // their
1524         // lldb-host endianness or the target endianness.. I doubt this'll ever
1525         // come up but I'll opt for assuming big endian regardless.
1526         switch (size) {
1527         case 1:
1528           ptr = ptr & 0xff;
1529           break;
1530         case 2:
1531           ptr = ptr & 0xffff;
1532           break;
1533         case 3:
1534           ptr = ptr & 0xffffff;
1535           break;
1536         case 4:
1537           ptr = ptr & 0xffffffff;
1538           break;
1539         // the casts are added to work around the case where intptr_t is a 32
1540         // bit quantity;
1541         // presumably we won't hit the 5..7 cases if (void*) is 32-bits in this
1542         // program.
1543         case 5:
1544           ptr = (intptr_t)ptr & 0xffffffffffULL;
1545           break;
1546         case 6:
1547           ptr = (intptr_t)ptr & 0xffffffffffffULL;
1548           break;
1549         case 7:
1550           ptr = (intptr_t)ptr & 0xffffffffffffffULL;
1551           break;
1552         default:
1553           break;
1554         }
1555         stack.back().GetScalar() = ptr;
1556         stack.back().ClearContext();
1557       } break;
1558       case Value::eValueTypeLoadAddress:
1559         if (exe_ctx) {
1560           if (process) {
1561             lldb::addr_t pointer_addr =
1562                 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
1563             uint8_t addr_bytes[sizeof(lldb::addr_t)];
1564             Status error;
1565             if (process->ReadMemory(pointer_addr, &addr_bytes, size, error) ==
1566                 size) {
1567               DataExtractor addr_data(addr_bytes, sizeof(addr_bytes),
1568                                       process->GetByteOrder(), size);
1569               lldb::offset_t addr_data_offset = 0;
1570               switch (size) {
1571               case 1:
1572                 stack.back().GetScalar() = addr_data.GetU8(&addr_data_offset);
1573                 break;
1574               case 2:
1575                 stack.back().GetScalar() = addr_data.GetU16(&addr_data_offset);
1576                 break;
1577               case 4:
1578                 stack.back().GetScalar() = addr_data.GetU32(&addr_data_offset);
1579                 break;
1580               case 8:
1581                 stack.back().GetScalar() = addr_data.GetU64(&addr_data_offset);
1582                 break;
1583               default:
1584                 stack.back().GetScalar() =
1585                     addr_data.GetPointer(&addr_data_offset);
1586               }
1587               stack.back().ClearContext();
1588             } else {
1589               if (error_ptr)
1590                 error_ptr->SetErrorStringWithFormat(
1591                     "Failed to dereference pointer from 0x%" PRIx64
1592                     " for DW_OP_deref: %s\n",
1593                     pointer_addr, error.AsCString());
1594               return false;
1595             }
1596           } else {
1597             if (error_ptr)
1598               error_ptr->SetErrorStringWithFormat(
1599                   "NULL process for DW_OP_deref.\n");
1600             return false;
1601           }
1602         } else {
1603           if (error_ptr)
1604             error_ptr->SetErrorStringWithFormat(
1605                 "NULL execution context for DW_OP_deref.\n");
1606           return false;
1607         }
1608         break;
1609 
1610       default:
1611         break;
1612       }
1613 
1614     } break;
1615 
1616     //----------------------------------------------------------------------
1617     // OPCODE: DW_OP_xderef_size
1618     // OPERANDS: 1
1619     //  1 - uint8_t that specifies the size of the data to dereference.
1620     // DESCRIPTION: Behaves like the DW_OP_xderef operation: the entry at
1621     // the top of the stack is treated as an address. The second stack entry is
1622     // treated as an "address space identifier" for those architectures that
1623     // support multiple address spaces. The top two stack elements are popped,
1624     // a data item is retrieved through an implementation-defined address
1625     // calculation and pushed as the new stack top. In the DW_OP_xderef_size
1626     // operation, however, the size in bytes of the data retrieved from the
1627     // dereferenced address is specified by the single operand. This operand is
1628     // a 1-byte unsigned integral constant whose value may not be larger than
1629     // the size of an address on the target machine. The data retrieved is zero
1630     // extended to the size of an address on the target machine before being
1631     // pushed on the expression stack.
1632     //----------------------------------------------------------------------
1633     case DW_OP_xderef_size:
1634       if (error_ptr)
1635         error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef_size.");
1636       return false;
1637     //----------------------------------------------------------------------
1638     // OPCODE: DW_OP_xderef
1639     // OPERANDS: none
1640     // DESCRIPTION: Provides an extended dereference mechanism. The entry at
1641     // the top of the stack is treated as an address. The second stack entry is
1642     // treated as an "address space identifier" for those architectures that
1643     // support multiple address spaces. The top two stack elements are popped,
1644     // a data item is retrieved through an implementation-defined address
1645     // calculation and pushed as the new stack top. The size of the data
1646     // retrieved from the dereferenced address is the size of an address on the
1647     // target machine.
1648     //----------------------------------------------------------------------
1649     case DW_OP_xderef:
1650       if (error_ptr)
1651         error_ptr->SetErrorString("Unimplemented opcode: DW_OP_xderef.");
1652       return false;
1653 
1654     //----------------------------------------------------------------------
1655     // All DW_OP_constXXX opcodes have a single operand as noted below:
1656     //
1657     // Opcode           Operand 1
1658     // ---------------  ----------------------------------------------------
1659     // DW_OP_const1u    1-byte unsigned integer constant DW_OP_const1s
1660     // 1-byte signed integer constant DW_OP_const2u    2-byte unsigned integer
1661     // constant DW_OP_const2s    2-byte signed integer constant DW_OP_const4u
1662     // 4-byte unsigned integer constant DW_OP_const4s    4-byte signed integer
1663     // constant DW_OP_const8u    8-byte unsigned integer constant DW_OP_const8s
1664     // 8-byte signed integer constant DW_OP_constu     unsigned LEB128 integer
1665     // constant DW_OP_consts     signed LEB128 integer constant
1666     //----------------------------------------------------------------------
1667     case DW_OP_const1u:
1668       stack.push_back(Scalar((uint8_t)opcodes.GetU8(&offset)));
1669       break;
1670     case DW_OP_const1s:
1671       stack.push_back(Scalar((int8_t)opcodes.GetU8(&offset)));
1672       break;
1673     case DW_OP_const2u:
1674       stack.push_back(Scalar((uint16_t)opcodes.GetU16(&offset)));
1675       break;
1676     case DW_OP_const2s:
1677       stack.push_back(Scalar((int16_t)opcodes.GetU16(&offset)));
1678       break;
1679     case DW_OP_const4u:
1680       stack.push_back(Scalar((uint32_t)opcodes.GetU32(&offset)));
1681       break;
1682     case DW_OP_const4s:
1683       stack.push_back(Scalar((int32_t)opcodes.GetU32(&offset)));
1684       break;
1685     case DW_OP_const8u:
1686       stack.push_back(Scalar((uint64_t)opcodes.GetU64(&offset)));
1687       break;
1688     case DW_OP_const8s:
1689       stack.push_back(Scalar((int64_t)opcodes.GetU64(&offset)));
1690       break;
1691     case DW_OP_constu:
1692       stack.push_back(Scalar(opcodes.GetULEB128(&offset)));
1693       break;
1694     case DW_OP_consts:
1695       stack.push_back(Scalar(opcodes.GetSLEB128(&offset)));
1696       break;
1697 
1698     //----------------------------------------------------------------------
1699     // OPCODE: DW_OP_dup
1700     // OPERANDS: none
1701     // DESCRIPTION: duplicates the value at the top of the stack
1702     //----------------------------------------------------------------------
1703     case DW_OP_dup:
1704       if (stack.empty()) {
1705         if (error_ptr)
1706           error_ptr->SetErrorString("Expression stack empty for DW_OP_dup.");
1707         return false;
1708       } else
1709         stack.push_back(stack.back());
1710       break;
1711 
1712     //----------------------------------------------------------------------
1713     // OPCODE: DW_OP_drop
1714     // OPERANDS: none
1715     // DESCRIPTION: pops the value at the top of the stack
1716     //----------------------------------------------------------------------
1717     case DW_OP_drop:
1718       if (stack.empty()) {
1719         if (error_ptr)
1720           error_ptr->SetErrorString("Expression stack empty for DW_OP_drop.");
1721         return false;
1722       } else
1723         stack.pop_back();
1724       break;
1725 
1726     //----------------------------------------------------------------------
1727     // OPCODE: DW_OP_over
1728     // OPERANDS: none
1729     // DESCRIPTION: Duplicates the entry currently second in the stack at
1730     // the top of the stack.
1731     //----------------------------------------------------------------------
1732     case DW_OP_over:
1733       if (stack.size() < 2) {
1734         if (error_ptr)
1735           error_ptr->SetErrorString(
1736               "Expression stack needs at least 2 items for DW_OP_over.");
1737         return false;
1738       } else
1739         stack.push_back(stack[stack.size() - 2]);
1740       break;
1741 
1742     //----------------------------------------------------------------------
1743     // OPCODE: DW_OP_pick
1744     // OPERANDS: uint8_t index into the current stack
1745     // DESCRIPTION: The stack entry with the specified index (0 through 255,
1746     // inclusive) is pushed on the stack
1747     //----------------------------------------------------------------------
1748     case DW_OP_pick: {
1749       uint8_t pick_idx = opcodes.GetU8(&offset);
1750       if (pick_idx < stack.size())
1751         stack.push_back(stack[pick_idx]);
1752       else {
1753         if (error_ptr)
1754           error_ptr->SetErrorStringWithFormat(
1755               "Index %u out of range for DW_OP_pick.\n", pick_idx);
1756         return false;
1757       }
1758     } break;
1759 
1760     //----------------------------------------------------------------------
1761     // OPCODE: DW_OP_swap
1762     // OPERANDS: none
1763     // DESCRIPTION: swaps the top two stack entries. The entry at the top
1764     // of the stack becomes the second stack entry, and the second entry
1765     // becomes the top of the stack
1766     //----------------------------------------------------------------------
1767     case DW_OP_swap:
1768       if (stack.size() < 2) {
1769         if (error_ptr)
1770           error_ptr->SetErrorString(
1771               "Expression stack needs at least 2 items for DW_OP_swap.");
1772         return false;
1773       } else {
1774         tmp = stack.back();
1775         stack.back() = stack[stack.size() - 2];
1776         stack[stack.size() - 2] = tmp;
1777       }
1778       break;
1779 
1780     //----------------------------------------------------------------------
1781     // OPCODE: DW_OP_rot
1782     // OPERANDS: none
1783     // DESCRIPTION: Rotates the first three stack entries. The entry at
1784     // the top of the stack becomes the third stack entry, the second entry
1785     // becomes the top of the stack, and the third entry becomes the second
1786     // entry.
1787     //----------------------------------------------------------------------
1788     case DW_OP_rot:
1789       if (stack.size() < 3) {
1790         if (error_ptr)
1791           error_ptr->SetErrorString(
1792               "Expression stack needs at least 3 items for DW_OP_rot.");
1793         return false;
1794       } else {
1795         size_t last_idx = stack.size() - 1;
1796         Value old_top = stack[last_idx];
1797         stack[last_idx] = stack[last_idx - 1];
1798         stack[last_idx - 1] = stack[last_idx - 2];
1799         stack[last_idx - 2] = old_top;
1800       }
1801       break;
1802 
1803     //----------------------------------------------------------------------
1804     // OPCODE: DW_OP_abs
1805     // OPERANDS: none
1806     // DESCRIPTION: pops the top stack entry, interprets it as a signed
1807     // value and pushes its absolute value. If the absolute value can not be
1808     // represented, the result is undefined.
1809     //----------------------------------------------------------------------
1810     case DW_OP_abs:
1811       if (stack.empty()) {
1812         if (error_ptr)
1813           error_ptr->SetErrorString(
1814               "Expression stack needs at least 1 item for DW_OP_abs.");
1815         return false;
1816       } else if (stack.back().ResolveValue(exe_ctx).AbsoluteValue() == false) {
1817         if (error_ptr)
1818           error_ptr->SetErrorString(
1819               "Failed to take the absolute value of the first stack item.");
1820         return false;
1821       }
1822       break;
1823 
1824     //----------------------------------------------------------------------
1825     // OPCODE: DW_OP_and
1826     // OPERANDS: none
1827     // DESCRIPTION: pops the top two stack values, performs a bitwise and
1828     // operation on the two, and pushes the result.
1829     //----------------------------------------------------------------------
1830     case DW_OP_and:
1831       if (stack.size() < 2) {
1832         if (error_ptr)
1833           error_ptr->SetErrorString(
1834               "Expression stack needs at least 2 items for DW_OP_and.");
1835         return false;
1836       } else {
1837         tmp = stack.back();
1838         stack.pop_back();
1839         stack.back().ResolveValue(exe_ctx) =
1840             stack.back().ResolveValue(exe_ctx) & tmp.ResolveValue(exe_ctx);
1841       }
1842       break;
1843 
1844     //----------------------------------------------------------------------
1845     // OPCODE: DW_OP_div
1846     // OPERANDS: none
1847     // DESCRIPTION: pops the top two stack values, divides the former second
1848     // entry by the former top of the stack using signed division, and pushes
1849     // the result.
1850     //----------------------------------------------------------------------
1851     case DW_OP_div:
1852       if (stack.size() < 2) {
1853         if (error_ptr)
1854           error_ptr->SetErrorString(
1855               "Expression stack needs at least 2 items for DW_OP_div.");
1856         return false;
1857       } else {
1858         tmp = stack.back();
1859         if (tmp.ResolveValue(exe_ctx).IsZero()) {
1860           if (error_ptr)
1861             error_ptr->SetErrorString("Divide by zero.");
1862           return false;
1863         } else {
1864           stack.pop_back();
1865           stack.back() =
1866               stack.back().ResolveValue(exe_ctx) / tmp.ResolveValue(exe_ctx);
1867           if (!stack.back().ResolveValue(exe_ctx).IsValid()) {
1868             if (error_ptr)
1869               error_ptr->SetErrorString("Divide failed.");
1870             return false;
1871           }
1872         }
1873       }
1874       break;
1875 
1876     //----------------------------------------------------------------------
1877     // OPCODE: DW_OP_minus
1878     // OPERANDS: none
1879     // DESCRIPTION: pops the top two stack values, subtracts the former top
1880     // of the stack from the former second entry, and pushes the result.
1881     //----------------------------------------------------------------------
1882     case DW_OP_minus:
1883       if (stack.size() < 2) {
1884         if (error_ptr)
1885           error_ptr->SetErrorString(
1886               "Expression stack needs at least 2 items for DW_OP_minus.");
1887         return false;
1888       } else {
1889         tmp = stack.back();
1890         stack.pop_back();
1891         stack.back().ResolveValue(exe_ctx) =
1892             stack.back().ResolveValue(exe_ctx) - tmp.ResolveValue(exe_ctx);
1893       }
1894       break;
1895 
1896     //----------------------------------------------------------------------
1897     // OPCODE: DW_OP_mod
1898     // OPERANDS: none
1899     // DESCRIPTION: pops the top two stack values and pushes the result of
1900     // the calculation: former second stack entry modulo the former top of the
1901     // stack.
1902     //----------------------------------------------------------------------
1903     case DW_OP_mod:
1904       if (stack.size() < 2) {
1905         if (error_ptr)
1906           error_ptr->SetErrorString(
1907               "Expression stack needs at least 2 items for DW_OP_mod.");
1908         return false;
1909       } else {
1910         tmp = stack.back();
1911         stack.pop_back();
1912         stack.back().ResolveValue(exe_ctx) =
1913             stack.back().ResolveValue(exe_ctx) % tmp.ResolveValue(exe_ctx);
1914       }
1915       break;
1916 
1917     //----------------------------------------------------------------------
1918     // OPCODE: DW_OP_mul
1919     // OPERANDS: none
1920     // DESCRIPTION: pops the top two stack entries, multiplies them
1921     // together, and pushes the result.
1922     //----------------------------------------------------------------------
1923     case DW_OP_mul:
1924       if (stack.size() < 2) {
1925         if (error_ptr)
1926           error_ptr->SetErrorString(
1927               "Expression stack needs at least 2 items for DW_OP_mul.");
1928         return false;
1929       } else {
1930         tmp = stack.back();
1931         stack.pop_back();
1932         stack.back().ResolveValue(exe_ctx) =
1933             stack.back().ResolveValue(exe_ctx) * tmp.ResolveValue(exe_ctx);
1934       }
1935       break;
1936 
1937     //----------------------------------------------------------------------
1938     // OPCODE: DW_OP_neg
1939     // OPERANDS: none
1940     // DESCRIPTION: pops the top stack entry, and pushes its negation.
1941     //----------------------------------------------------------------------
1942     case DW_OP_neg:
1943       if (stack.empty()) {
1944         if (error_ptr)
1945           error_ptr->SetErrorString(
1946               "Expression stack needs at least 1 item for DW_OP_neg.");
1947         return false;
1948       } else {
1949         if (stack.back().ResolveValue(exe_ctx).UnaryNegate() == false) {
1950           if (error_ptr)
1951             error_ptr->SetErrorString("Unary negate failed.");
1952           return false;
1953         }
1954       }
1955       break;
1956 
1957     //----------------------------------------------------------------------
1958     // OPCODE: DW_OP_not
1959     // OPERANDS: none
1960     // DESCRIPTION: pops the top stack entry, and pushes its bitwise
1961     // complement
1962     //----------------------------------------------------------------------
1963     case DW_OP_not:
1964       if (stack.empty()) {
1965         if (error_ptr)
1966           error_ptr->SetErrorString(
1967               "Expression stack needs at least 1 item for DW_OP_not.");
1968         return false;
1969       } else {
1970         if (stack.back().ResolveValue(exe_ctx).OnesComplement() == false) {
1971           if (error_ptr)
1972             error_ptr->SetErrorString("Logical NOT failed.");
1973           return false;
1974         }
1975       }
1976       break;
1977 
1978     //----------------------------------------------------------------------
1979     // OPCODE: DW_OP_or
1980     // OPERANDS: none
1981     // DESCRIPTION: pops the top two stack entries, performs a bitwise or
1982     // operation on the two, and pushes the result.
1983     //----------------------------------------------------------------------
1984     case DW_OP_or:
1985       if (stack.size() < 2) {
1986         if (error_ptr)
1987           error_ptr->SetErrorString(
1988               "Expression stack needs at least 2 items for DW_OP_or.");
1989         return false;
1990       } else {
1991         tmp = stack.back();
1992         stack.pop_back();
1993         stack.back().ResolveValue(exe_ctx) =
1994             stack.back().ResolveValue(exe_ctx) | tmp.ResolveValue(exe_ctx);
1995       }
1996       break;
1997 
1998     //----------------------------------------------------------------------
1999     // OPCODE: DW_OP_plus
2000     // OPERANDS: none
2001     // DESCRIPTION: pops the top two stack entries, adds them together, and
2002     // pushes the result.
2003     //----------------------------------------------------------------------
2004     case DW_OP_plus:
2005       if (stack.size() < 2) {
2006         if (error_ptr)
2007           error_ptr->SetErrorString(
2008               "Expression stack needs at least 2 items for DW_OP_plus.");
2009         return false;
2010       } else {
2011         tmp = stack.back();
2012         stack.pop_back();
2013         stack.back().GetScalar() += tmp.GetScalar();
2014       }
2015       break;
2016 
2017     //----------------------------------------------------------------------
2018     // OPCODE: DW_OP_plus_uconst
2019     // OPERANDS: none
2020     // DESCRIPTION: pops the top stack entry, adds it to the unsigned LEB128
2021     // constant operand and pushes the result.
2022     //----------------------------------------------------------------------
2023     case DW_OP_plus_uconst:
2024       if (stack.empty()) {
2025         if (error_ptr)
2026           error_ptr->SetErrorString(
2027               "Expression stack needs at least 1 item for DW_OP_plus_uconst.");
2028         return false;
2029       } else {
2030         const uint64_t uconst_value = opcodes.GetULEB128(&offset);
2031         // Implicit conversion from a UINT to a Scalar...
2032         stack.back().GetScalar() += uconst_value;
2033         if (!stack.back().GetScalar().IsValid()) {
2034           if (error_ptr)
2035             error_ptr->SetErrorString("DW_OP_plus_uconst failed.");
2036           return false;
2037         }
2038       }
2039       break;
2040 
2041     //----------------------------------------------------------------------
2042     // OPCODE: DW_OP_shl
2043     // OPERANDS: none
2044     // DESCRIPTION:  pops the top two stack entries, shifts the former
2045     // second entry left by the number of bits specified by the former top of
2046     // the stack, and pushes the result.
2047     //----------------------------------------------------------------------
2048     case DW_OP_shl:
2049       if (stack.size() < 2) {
2050         if (error_ptr)
2051           error_ptr->SetErrorString(
2052               "Expression stack needs at least 2 items for DW_OP_shl.");
2053         return false;
2054       } else {
2055         tmp = stack.back();
2056         stack.pop_back();
2057         stack.back().ResolveValue(exe_ctx) <<= tmp.ResolveValue(exe_ctx);
2058       }
2059       break;
2060 
2061     //----------------------------------------------------------------------
2062     // OPCODE: DW_OP_shr
2063     // OPERANDS: none
2064     // DESCRIPTION: pops the top two stack entries, shifts the former second
2065     // entry right logically (filling with zero bits) by the number of bits
2066     // specified by the former top of the stack, and pushes the result.
2067     //----------------------------------------------------------------------
2068     case DW_OP_shr:
2069       if (stack.size() < 2) {
2070         if (error_ptr)
2071           error_ptr->SetErrorString(
2072               "Expression stack needs at least 2 items for DW_OP_shr.");
2073         return false;
2074       } else {
2075         tmp = stack.back();
2076         stack.pop_back();
2077         if (stack.back().ResolveValue(exe_ctx).ShiftRightLogical(
2078                 tmp.ResolveValue(exe_ctx)) == false) {
2079           if (error_ptr)
2080             error_ptr->SetErrorString("DW_OP_shr failed.");
2081           return false;
2082         }
2083       }
2084       break;
2085 
2086     //----------------------------------------------------------------------
2087     // OPCODE: DW_OP_shra
2088     // OPERANDS: none
2089     // DESCRIPTION: pops the top two stack entries, shifts the former second
2090     // entry right arithmetically (divide the magnitude by 2, keep the same
2091     // sign for the result) by the number of bits specified by the former top
2092     // of the stack, and pushes the result.
2093     //----------------------------------------------------------------------
2094     case DW_OP_shra:
2095       if (stack.size() < 2) {
2096         if (error_ptr)
2097           error_ptr->SetErrorString(
2098               "Expression stack needs at least 2 items for DW_OP_shra.");
2099         return false;
2100       } else {
2101         tmp = stack.back();
2102         stack.pop_back();
2103         stack.back().ResolveValue(exe_ctx) >>= tmp.ResolveValue(exe_ctx);
2104       }
2105       break;
2106 
2107     //----------------------------------------------------------------------
2108     // OPCODE: DW_OP_xor
2109     // OPERANDS: none
2110     // DESCRIPTION: pops the top two stack entries, performs the bitwise
2111     // exclusive-or operation on the two, and pushes the result.
2112     //----------------------------------------------------------------------
2113     case DW_OP_xor:
2114       if (stack.size() < 2) {
2115         if (error_ptr)
2116           error_ptr->SetErrorString(
2117               "Expression stack needs at least 2 items for DW_OP_xor.");
2118         return false;
2119       } else {
2120         tmp = stack.back();
2121         stack.pop_back();
2122         stack.back().ResolveValue(exe_ctx) =
2123             stack.back().ResolveValue(exe_ctx) ^ tmp.ResolveValue(exe_ctx);
2124       }
2125       break;
2126 
2127     //----------------------------------------------------------------------
2128     // OPCODE: DW_OP_skip
2129     // OPERANDS: int16_t
2130     // DESCRIPTION:  An unconditional branch. Its single operand is a 2-byte
2131     // signed integer constant. The 2-byte constant is the number of bytes of
2132     // the DWARF expression to skip forward or backward from the current
2133     // operation, beginning after the 2-byte constant.
2134     //----------------------------------------------------------------------
2135     case DW_OP_skip: {
2136       int16_t skip_offset = (int16_t)opcodes.GetU16(&offset);
2137       lldb::offset_t new_offset = offset + skip_offset;
2138       if (new_offset >= opcodes_offset && new_offset < end_offset)
2139         offset = new_offset;
2140       else {
2141         if (error_ptr)
2142           error_ptr->SetErrorString("Invalid opcode offset in DW_OP_skip.");
2143         return false;
2144       }
2145     } break;
2146 
2147     //----------------------------------------------------------------------
2148     // OPCODE: DW_OP_bra
2149     // OPERANDS: int16_t
2150     // DESCRIPTION: A conditional branch. Its single operand is a 2-byte
2151     // signed integer constant. This operation pops the top of stack. If the
2152     // value popped is not the constant 0, the 2-byte constant operand is the
2153     // number of bytes of the DWARF expression to skip forward or backward from
2154     // the current operation, beginning after the 2-byte constant.
2155     //----------------------------------------------------------------------
2156     case DW_OP_bra:
2157       if (stack.empty()) {
2158         if (error_ptr)
2159           error_ptr->SetErrorString(
2160               "Expression stack needs at least 1 item for DW_OP_bra.");
2161         return false;
2162       } else {
2163         tmp = stack.back();
2164         stack.pop_back();
2165         int16_t bra_offset = (int16_t)opcodes.GetU16(&offset);
2166         Scalar zero(0);
2167         if (tmp.ResolveValue(exe_ctx) != zero) {
2168           lldb::offset_t new_offset = offset + bra_offset;
2169           if (new_offset >= opcodes_offset && new_offset < end_offset)
2170             offset = new_offset;
2171           else {
2172             if (error_ptr)
2173               error_ptr->SetErrorString("Invalid opcode offset in DW_OP_bra.");
2174             return false;
2175           }
2176         }
2177       }
2178       break;
2179 
2180     //----------------------------------------------------------------------
2181     // OPCODE: DW_OP_eq
2182     // OPERANDS: none
2183     // DESCRIPTION: pops the top two stack values, compares using the
2184     // equals (==) operator.
2185     // STACK RESULT: push the constant value 1 onto the stack if the result
2186     // of the operation is true or the constant value 0 if the result of the
2187     // operation is false.
2188     //----------------------------------------------------------------------
2189     case DW_OP_eq:
2190       if (stack.size() < 2) {
2191         if (error_ptr)
2192           error_ptr->SetErrorString(
2193               "Expression stack needs at least 2 items for DW_OP_eq.");
2194         return false;
2195       } else {
2196         tmp = stack.back();
2197         stack.pop_back();
2198         stack.back().ResolveValue(exe_ctx) =
2199             stack.back().ResolveValue(exe_ctx) == tmp.ResolveValue(exe_ctx);
2200       }
2201       break;
2202 
2203     //----------------------------------------------------------------------
2204     // OPCODE: DW_OP_ge
2205     // OPERANDS: none
2206     // DESCRIPTION: pops the top two stack values, compares using the
2207     // greater than or equal to (>=) operator.
2208     // STACK RESULT: push the constant value 1 onto the stack if the result
2209     // of the operation is true or the constant value 0 if the result of the
2210     // operation is false.
2211     //----------------------------------------------------------------------
2212     case DW_OP_ge:
2213       if (stack.size() < 2) {
2214         if (error_ptr)
2215           error_ptr->SetErrorString(
2216               "Expression stack needs at least 2 items for DW_OP_ge.");
2217         return false;
2218       } else {
2219         tmp = stack.back();
2220         stack.pop_back();
2221         stack.back().ResolveValue(exe_ctx) =
2222             stack.back().ResolveValue(exe_ctx) >= tmp.ResolveValue(exe_ctx);
2223       }
2224       break;
2225 
2226     //----------------------------------------------------------------------
2227     // OPCODE: DW_OP_gt
2228     // OPERANDS: none
2229     // DESCRIPTION: pops the top two stack values, compares using the
2230     // greater than (>) operator.
2231     // STACK RESULT: push the constant value 1 onto the stack if the result
2232     // of the operation is true or the constant value 0 if the result of the
2233     // operation is false.
2234     //----------------------------------------------------------------------
2235     case DW_OP_gt:
2236       if (stack.size() < 2) {
2237         if (error_ptr)
2238           error_ptr->SetErrorString(
2239               "Expression stack needs at least 2 items for DW_OP_gt.");
2240         return false;
2241       } else {
2242         tmp = stack.back();
2243         stack.pop_back();
2244         stack.back().ResolveValue(exe_ctx) =
2245             stack.back().ResolveValue(exe_ctx) > tmp.ResolveValue(exe_ctx);
2246       }
2247       break;
2248 
2249     //----------------------------------------------------------------------
2250     // OPCODE: DW_OP_le
2251     // OPERANDS: none
2252     // DESCRIPTION: pops the top two stack values, compares using the
2253     // less than or equal to (<=) operator.
2254     // STACK RESULT: push the constant value 1 onto the stack if the result
2255     // of the operation is true or the constant value 0 if the result of the
2256     // operation is false.
2257     //----------------------------------------------------------------------
2258     case DW_OP_le:
2259       if (stack.size() < 2) {
2260         if (error_ptr)
2261           error_ptr->SetErrorString(
2262               "Expression stack needs at least 2 items for DW_OP_le.");
2263         return false;
2264       } else {
2265         tmp = stack.back();
2266         stack.pop_back();
2267         stack.back().ResolveValue(exe_ctx) =
2268             stack.back().ResolveValue(exe_ctx) <= tmp.ResolveValue(exe_ctx);
2269       }
2270       break;
2271 
2272     //----------------------------------------------------------------------
2273     // OPCODE: DW_OP_lt
2274     // OPERANDS: none
2275     // DESCRIPTION: pops the top two stack values, compares using the
2276     // less than (<) operator.
2277     // STACK RESULT: push the constant value 1 onto the stack if the result
2278     // of the operation is true or the constant value 0 if the result of the
2279     // operation is false.
2280     //----------------------------------------------------------------------
2281     case DW_OP_lt:
2282       if (stack.size() < 2) {
2283         if (error_ptr)
2284           error_ptr->SetErrorString(
2285               "Expression stack needs at least 2 items for DW_OP_lt.");
2286         return false;
2287       } else {
2288         tmp = stack.back();
2289         stack.pop_back();
2290         stack.back().ResolveValue(exe_ctx) =
2291             stack.back().ResolveValue(exe_ctx) < tmp.ResolveValue(exe_ctx);
2292       }
2293       break;
2294 
2295     //----------------------------------------------------------------------
2296     // OPCODE: DW_OP_ne
2297     // OPERANDS: none
2298     // DESCRIPTION: pops the top two stack values, compares using the
2299     // not equal (!=) operator.
2300     // STACK RESULT: push the constant value 1 onto the stack if the result
2301     // of the operation is true or the constant value 0 if the result of the
2302     // operation is false.
2303     //----------------------------------------------------------------------
2304     case DW_OP_ne:
2305       if (stack.size() < 2) {
2306         if (error_ptr)
2307           error_ptr->SetErrorString(
2308               "Expression stack needs at least 2 items for DW_OP_ne.");
2309         return false;
2310       } else {
2311         tmp = stack.back();
2312         stack.pop_back();
2313         stack.back().ResolveValue(exe_ctx) =
2314             stack.back().ResolveValue(exe_ctx) != tmp.ResolveValue(exe_ctx);
2315       }
2316       break;
2317 
2318     //----------------------------------------------------------------------
2319     // OPCODE: DW_OP_litn
2320     // OPERANDS: none
2321     // DESCRIPTION: encode the unsigned literal values from 0 through 31.
2322     // STACK RESULT: push the unsigned literal constant value onto the top
2323     // of the stack.
2324     //----------------------------------------------------------------------
2325     case DW_OP_lit0:
2326     case DW_OP_lit1:
2327     case DW_OP_lit2:
2328     case DW_OP_lit3:
2329     case DW_OP_lit4:
2330     case DW_OP_lit5:
2331     case DW_OP_lit6:
2332     case DW_OP_lit7:
2333     case DW_OP_lit8:
2334     case DW_OP_lit9:
2335     case DW_OP_lit10:
2336     case DW_OP_lit11:
2337     case DW_OP_lit12:
2338     case DW_OP_lit13:
2339     case DW_OP_lit14:
2340     case DW_OP_lit15:
2341     case DW_OP_lit16:
2342     case DW_OP_lit17:
2343     case DW_OP_lit18:
2344     case DW_OP_lit19:
2345     case DW_OP_lit20:
2346     case DW_OP_lit21:
2347     case DW_OP_lit22:
2348     case DW_OP_lit23:
2349     case DW_OP_lit24:
2350     case DW_OP_lit25:
2351     case DW_OP_lit26:
2352     case DW_OP_lit27:
2353     case DW_OP_lit28:
2354     case DW_OP_lit29:
2355     case DW_OP_lit30:
2356     case DW_OP_lit31:
2357       stack.push_back(Scalar(op - DW_OP_lit0));
2358       break;
2359 
2360     //----------------------------------------------------------------------
2361     // OPCODE: DW_OP_regN
2362     // OPERANDS: none
2363     // DESCRIPTION: Push the value in register n on the top of the stack.
2364     //----------------------------------------------------------------------
2365     case DW_OP_reg0:
2366     case DW_OP_reg1:
2367     case DW_OP_reg2:
2368     case DW_OP_reg3:
2369     case DW_OP_reg4:
2370     case DW_OP_reg5:
2371     case DW_OP_reg6:
2372     case DW_OP_reg7:
2373     case DW_OP_reg8:
2374     case DW_OP_reg9:
2375     case DW_OP_reg10:
2376     case DW_OP_reg11:
2377     case DW_OP_reg12:
2378     case DW_OP_reg13:
2379     case DW_OP_reg14:
2380     case DW_OP_reg15:
2381     case DW_OP_reg16:
2382     case DW_OP_reg17:
2383     case DW_OP_reg18:
2384     case DW_OP_reg19:
2385     case DW_OP_reg20:
2386     case DW_OP_reg21:
2387     case DW_OP_reg22:
2388     case DW_OP_reg23:
2389     case DW_OP_reg24:
2390     case DW_OP_reg25:
2391     case DW_OP_reg26:
2392     case DW_OP_reg27:
2393     case DW_OP_reg28:
2394     case DW_OP_reg29:
2395     case DW_OP_reg30:
2396     case DW_OP_reg31: {
2397       reg_num = op - DW_OP_reg0;
2398 
2399       if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp))
2400         stack.push_back(tmp);
2401       else
2402         return false;
2403     } break;
2404     //----------------------------------------------------------------------
2405     // OPCODE: DW_OP_regx
2406     // OPERANDS:
2407     //      ULEB128 literal operand that encodes the register.
2408     // DESCRIPTION: Push the value in register on the top of the stack.
2409     //----------------------------------------------------------------------
2410     case DW_OP_regx: {
2411       reg_num = opcodes.GetULEB128(&offset);
2412       if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr, tmp))
2413         stack.push_back(tmp);
2414       else
2415         return false;
2416     } break;
2417 
2418     //----------------------------------------------------------------------
2419     // OPCODE: DW_OP_bregN
2420     // OPERANDS:
2421     //      SLEB128 offset from register N
2422     // DESCRIPTION: Value is in memory at the address specified by register
2423     // N plus an offset.
2424     //----------------------------------------------------------------------
2425     case DW_OP_breg0:
2426     case DW_OP_breg1:
2427     case DW_OP_breg2:
2428     case DW_OP_breg3:
2429     case DW_OP_breg4:
2430     case DW_OP_breg5:
2431     case DW_OP_breg6:
2432     case DW_OP_breg7:
2433     case DW_OP_breg8:
2434     case DW_OP_breg9:
2435     case DW_OP_breg10:
2436     case DW_OP_breg11:
2437     case DW_OP_breg12:
2438     case DW_OP_breg13:
2439     case DW_OP_breg14:
2440     case DW_OP_breg15:
2441     case DW_OP_breg16:
2442     case DW_OP_breg17:
2443     case DW_OP_breg18:
2444     case DW_OP_breg19:
2445     case DW_OP_breg20:
2446     case DW_OP_breg21:
2447     case DW_OP_breg22:
2448     case DW_OP_breg23:
2449     case DW_OP_breg24:
2450     case DW_OP_breg25:
2451     case DW_OP_breg26:
2452     case DW_OP_breg27:
2453     case DW_OP_breg28:
2454     case DW_OP_breg29:
2455     case DW_OP_breg30:
2456     case DW_OP_breg31: {
2457       reg_num = op - DW_OP_breg0;
2458 
2459       if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr,
2460                                     tmp)) {
2461         int64_t breg_offset = opcodes.GetSLEB128(&offset);
2462         tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset;
2463         tmp.ClearContext();
2464         stack.push_back(tmp);
2465         stack.back().SetValueType(Value::eValueTypeLoadAddress);
2466       } else
2467         return false;
2468     } break;
2469     //----------------------------------------------------------------------
2470     // OPCODE: DW_OP_bregx
2471     // OPERANDS: 2
2472     //      ULEB128 literal operand that encodes the register.
2473     //      SLEB128 offset from register N
2474     // DESCRIPTION: Value is in memory at the address specified by register
2475     // N plus an offset.
2476     //----------------------------------------------------------------------
2477     case DW_OP_bregx: {
2478       reg_num = opcodes.GetULEB128(&offset);
2479 
2480       if (ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, error_ptr,
2481                                     tmp)) {
2482         int64_t breg_offset = opcodes.GetSLEB128(&offset);
2483         tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset;
2484         tmp.ClearContext();
2485         stack.push_back(tmp);
2486         stack.back().SetValueType(Value::eValueTypeLoadAddress);
2487       } else
2488         return false;
2489     } break;
2490 
2491     case DW_OP_fbreg:
2492       if (exe_ctx) {
2493         if (frame) {
2494           Scalar value;
2495           if (frame->GetFrameBaseValue(value, error_ptr)) {
2496             int64_t fbreg_offset = opcodes.GetSLEB128(&offset);
2497             value += fbreg_offset;
2498             stack.push_back(value);
2499             stack.back().SetValueType(Value::eValueTypeLoadAddress);
2500           } else
2501             return false;
2502         } else {
2503           if (error_ptr)
2504             error_ptr->SetErrorString(
2505                 "Invalid stack frame in context for DW_OP_fbreg opcode.");
2506           return false;
2507         }
2508       } else {
2509         if (error_ptr)
2510           error_ptr->SetErrorStringWithFormat(
2511               "NULL execution context for DW_OP_fbreg.\n");
2512         return false;
2513       }
2514 
2515       break;
2516 
2517     //----------------------------------------------------------------------
2518     // OPCODE: DW_OP_nop
2519     // OPERANDS: none
2520     // DESCRIPTION: A place holder. It has no effect on the location stack
2521     // or any of its values.
2522     //----------------------------------------------------------------------
2523     case DW_OP_nop:
2524       break;
2525 
2526     //----------------------------------------------------------------------
2527     // OPCODE: DW_OP_piece
2528     // OPERANDS: 1
2529     //      ULEB128: byte size of the piece
2530     // DESCRIPTION: The operand describes the size in bytes of the piece of
2531     // the object referenced by the DWARF expression whose result is at the top
2532     // of the stack. If the piece is located in a register, but does not occupy
2533     // the entire register, the placement of the piece within that register is
2534     // defined by the ABI.
2535     //
2536     // Many compilers store a single variable in sets of registers, or store a
2537     // variable partially in memory and partially in registers. DW_OP_piece
2538     // provides a way of describing how large a part of a variable a particular
2539     // DWARF expression refers to.
2540     //----------------------------------------------------------------------
2541     case DW_OP_piece: {
2542       const uint64_t piece_byte_size = opcodes.GetULEB128(&offset);
2543 
2544       if (piece_byte_size > 0) {
2545         Value curr_piece;
2546 
2547         if (stack.empty()) {
2548           // In a multi-piece expression, this means that the current piece is
2549           // not available. Fill with zeros for now by resizing the data and
2550           // appending it
2551           curr_piece.ResizeData(piece_byte_size);
2552           ::memset(curr_piece.GetBuffer().GetBytes(), 0, piece_byte_size);
2553           pieces.AppendDataToHostBuffer(curr_piece);
2554         } else {
2555           Status error;
2556           // Extract the current piece into "curr_piece"
2557           Value curr_piece_source_value(stack.back());
2558           stack.pop_back();
2559 
2560           const Value::ValueType curr_piece_source_value_type =
2561               curr_piece_source_value.GetValueType();
2562           switch (curr_piece_source_value_type) {
2563           case Value::eValueTypeLoadAddress:
2564             if (process) {
2565               if (curr_piece.ResizeData(piece_byte_size) == piece_byte_size) {
2566                 lldb::addr_t load_addr =
2567                     curr_piece_source_value.GetScalar().ULongLong(
2568                         LLDB_INVALID_ADDRESS);
2569                 if (process->ReadMemory(
2570                         load_addr, curr_piece.GetBuffer().GetBytes(),
2571                         piece_byte_size, error) != piece_byte_size) {
2572                   if (error_ptr)
2573                     error_ptr->SetErrorStringWithFormat(
2574                         "failed to read memory DW_OP_piece(%" PRIu64
2575                         ") from 0x%" PRIx64,
2576                         piece_byte_size, load_addr);
2577                   return false;
2578                 }
2579               } else {
2580                 if (error_ptr)
2581                   error_ptr->SetErrorStringWithFormat(
2582                       "failed to resize the piece memory buffer for "
2583                       "DW_OP_piece(%" PRIu64 ")",
2584                       piece_byte_size);
2585                 return false;
2586               }
2587             }
2588             break;
2589 
2590           case Value::eValueTypeFileAddress:
2591           case Value::eValueTypeHostAddress:
2592             if (error_ptr) {
2593               lldb::addr_t addr = curr_piece_source_value.GetScalar().ULongLong(
2594                   LLDB_INVALID_ADDRESS);
2595               error_ptr->SetErrorStringWithFormat(
2596                   "failed to read memory DW_OP_piece(%" PRIu64
2597                   ") from %s address 0x%" PRIx64,
2598                   piece_byte_size, curr_piece_source_value.GetValueType() ==
2599                                            Value::eValueTypeFileAddress
2600                                        ? "file"
2601                                        : "host",
2602                   addr);
2603             }
2604             return false;
2605 
2606           case Value::eValueTypeScalar: {
2607             uint32_t bit_size = piece_byte_size * 8;
2608             uint32_t bit_offset = 0;
2609             if (!curr_piece_source_value.GetScalar().ExtractBitfield(
2610                     bit_size, bit_offset)) {
2611               if (error_ptr)
2612                 error_ptr->SetErrorStringWithFormat(
2613                     "unable to extract %" PRIu64 " bytes from a %" PRIu64
2614                     " byte scalar value.",
2615                     piece_byte_size,
2616                     (uint64_t)curr_piece_source_value.GetScalar()
2617                         .GetByteSize());
2618               return false;
2619             }
2620             curr_piece = curr_piece_source_value;
2621           } break;
2622 
2623           case Value::eValueTypeVector: {
2624             if (curr_piece_source_value.GetVector().length >= piece_byte_size)
2625               curr_piece_source_value.GetVector().length = piece_byte_size;
2626             else {
2627               if (error_ptr)
2628                 error_ptr->SetErrorStringWithFormat(
2629                     "unable to extract %" PRIu64 " bytes from a %" PRIu64
2630                     " byte vector value.",
2631                     piece_byte_size,
2632                     (uint64_t)curr_piece_source_value.GetVector().length);
2633               return false;
2634             }
2635           } break;
2636           }
2637 
2638           // Check if this is the first piece?
2639           if (op_piece_offset == 0) {
2640             // This is the first piece, we should push it back onto the stack
2641             // so subsequent pieces will be able to access this piece and add
2642             // to it
2643             if (pieces.AppendDataToHostBuffer(curr_piece) == 0) {
2644               if (error_ptr)
2645                 error_ptr->SetErrorString("failed to append piece data");
2646               return false;
2647             }
2648           } else {
2649             // If this is the second or later piece there should be a value on
2650             // the stack
2651             if (pieces.GetBuffer().GetByteSize() != op_piece_offset) {
2652               if (error_ptr)
2653                 error_ptr->SetErrorStringWithFormat(
2654                     "DW_OP_piece for offset %" PRIu64
2655                     " but top of stack is of size %" PRIu64,
2656                     op_piece_offset, pieces.GetBuffer().GetByteSize());
2657               return false;
2658             }
2659 
2660             if (pieces.AppendDataToHostBuffer(curr_piece) == 0) {
2661               if (error_ptr)
2662                 error_ptr->SetErrorString("failed to append piece data");
2663               return false;
2664             }
2665           }
2666           op_piece_offset += piece_byte_size;
2667         }
2668       }
2669     } break;
2670 
2671     case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3);
2672       if (stack.size() < 1) {
2673         if (error_ptr)
2674           error_ptr->SetErrorString(
2675               "Expression stack needs at least 1 item for DW_OP_bit_piece.");
2676         return false;
2677       } else {
2678         const uint64_t piece_bit_size = opcodes.GetULEB128(&offset);
2679         const uint64_t piece_bit_offset = opcodes.GetULEB128(&offset);
2680         switch (stack.back().GetValueType()) {
2681         case Value::eValueTypeScalar: {
2682           if (!stack.back().GetScalar().ExtractBitfield(piece_bit_size,
2683                                                         piece_bit_offset)) {
2684             if (error_ptr)
2685               error_ptr->SetErrorStringWithFormat(
2686                   "unable to extract %" PRIu64 " bit value with %" PRIu64
2687                   " bit offset from a %" PRIu64 " bit scalar value.",
2688                   piece_bit_size, piece_bit_offset,
2689                   (uint64_t)(stack.back().GetScalar().GetByteSize() * 8));
2690             return false;
2691           }
2692         } break;
2693 
2694         case Value::eValueTypeFileAddress:
2695         case Value::eValueTypeLoadAddress:
2696         case Value::eValueTypeHostAddress:
2697           if (error_ptr) {
2698             error_ptr->SetErrorStringWithFormat(
2699                 "unable to extract DW_OP_bit_piece(bit_size = %" PRIu64
2700                 ", bit_offset = %" PRIu64 ") from an address value.",
2701                 piece_bit_size, piece_bit_offset);
2702           }
2703           return false;
2704 
2705         case Value::eValueTypeVector:
2706           if (error_ptr) {
2707             error_ptr->SetErrorStringWithFormat(
2708                 "unable to extract DW_OP_bit_piece(bit_size = %" PRIu64
2709                 ", bit_offset = %" PRIu64 ") from a vector value.",
2710                 piece_bit_size, piece_bit_offset);
2711           }
2712           return false;
2713         }
2714       }
2715       break;
2716 
2717     //----------------------------------------------------------------------
2718     // OPCODE: DW_OP_push_object_address
2719     // OPERANDS: none
2720     // DESCRIPTION: Pushes the address of the object currently being
2721     // evaluated as part of evaluation of a user presented expression. This
2722     // object may correspond to an independent variable described by its own
2723     // DIE or it may be a component of an array, structure, or class whose
2724     // address has been dynamically determined by an earlier step during user
2725     // expression evaluation.
2726     //----------------------------------------------------------------------
2727     case DW_OP_push_object_address:
2728       if (object_address_ptr)
2729         stack.push_back(*object_address_ptr);
2730       else {
2731         if (error_ptr)
2732           error_ptr->SetErrorString("DW_OP_push_object_address used without "
2733                                     "specifying an object address");
2734         return false;
2735       }
2736       break;
2737 
2738     //----------------------------------------------------------------------
2739     // OPCODE: DW_OP_call2
2740     // OPERANDS:
2741     //      uint16_t compile unit relative offset of a DIE
2742     // DESCRIPTION: Performs subroutine calls during evaluation
2743     // of a DWARF expression. The operand is the 2-byte unsigned offset of a
2744     // debugging information entry in the current compilation unit.
2745     //
2746     // Operand interpretation is exactly like that for DW_FORM_ref2.
2747     //
2748     // This operation transfers control of DWARF expression evaluation to the
2749     // DW_AT_location attribute of the referenced DIE. If there is no such
2750     // attribute, then there is no effect. Execution of the DWARF expression of
2751     // a DW_AT_location attribute may add to and/or remove from values on the
2752     // stack. Execution returns to the point following the call when the end of
2753     // the attribute is reached. Values on the stack at the time of the call
2754     // may be used as parameters by the called expression and values left on
2755     // the stack by the called expression may be used as return values by prior
2756     // agreement between the calling and called expressions.
2757     //----------------------------------------------------------------------
2758     case DW_OP_call2:
2759       if (error_ptr)
2760         error_ptr->SetErrorString("Unimplemented opcode DW_OP_call2.");
2761       return false;
2762     //----------------------------------------------------------------------
2763     // OPCODE: DW_OP_call4
2764     // OPERANDS: 1
2765     //      uint32_t compile unit relative offset of a DIE
2766     // DESCRIPTION: Performs a subroutine call during evaluation of a DWARF
2767     // expression. For DW_OP_call4, the operand is a 4-byte unsigned offset of
2768     // a debugging information entry in  the current compilation unit.
2769     //
2770     // Operand interpretation DW_OP_call4 is exactly like that for
2771     // DW_FORM_ref4.
2772     //
2773     // This operation transfers control of DWARF expression evaluation to the
2774     // DW_AT_location attribute of the referenced DIE. If there is no such
2775     // attribute, then there is no effect. Execution of the DWARF expression of
2776     // a DW_AT_location attribute may add to and/or remove from values on the
2777     // stack. Execution returns to the point following the call when the end of
2778     // the attribute is reached. Values on the stack at the time of the call
2779     // may be used as parameters by the called expression and values left on
2780     // the stack by the called expression may be used as return values by prior
2781     // agreement between the calling and called expressions.
2782     //----------------------------------------------------------------------
2783     case DW_OP_call4:
2784       if (error_ptr)
2785         error_ptr->SetErrorString("Unimplemented opcode DW_OP_call4.");
2786       return false;
2787 
2788     //----------------------------------------------------------------------
2789     // OPCODE: DW_OP_stack_value
2790     // OPERANDS: None
2791     // DESCRIPTION: Specifies that the object does not exist in memory but
2792     // rather is a constant value.  The value from the top of the stack is the
2793     // value to be used.  This is the actual object value and not the location.
2794     //----------------------------------------------------------------------
2795     case DW_OP_stack_value:
2796       stack.back().SetValueType(Value::eValueTypeScalar);
2797       break;
2798 
2799     //----------------------------------------------------------------------
2800     // OPCODE: DW_OP_call_frame_cfa
2801     // OPERANDS: None
2802     // DESCRIPTION: Specifies a DWARF expression that pushes the value of
2803     // the canonical frame address consistent with the call frame information
2804     // located in .debug_frame (or in the FDEs of the eh_frame section).
2805     //----------------------------------------------------------------------
2806     case DW_OP_call_frame_cfa:
2807       if (frame) {
2808         // Note that we don't have to parse FDEs because this DWARF expression
2809         // is commonly evaluated with a valid stack frame.
2810         StackID id = frame->GetStackID();
2811         addr_t cfa = id.GetCallFrameAddress();
2812         if (cfa != LLDB_INVALID_ADDRESS) {
2813           stack.push_back(Scalar(cfa));
2814           stack.back().SetValueType(Value::eValueTypeLoadAddress);
2815         } else if (error_ptr)
2816           error_ptr->SetErrorString("Stack frame does not include a canonical "
2817                                     "frame address for DW_OP_call_frame_cfa "
2818                                     "opcode.");
2819       } else {
2820         if (error_ptr)
2821           error_ptr->SetErrorString("Invalid stack frame in context for "
2822                                     "DW_OP_call_frame_cfa opcode.");
2823         return false;
2824       }
2825       break;
2826 
2827     //----------------------------------------------------------------------
2828     // OPCODE: DW_OP_form_tls_address (or the old pre-DWARFv3 vendor extension
2829     // opcode, DW_OP_GNU_push_tls_address)
2830     // OPERANDS: none
2831     // DESCRIPTION: Pops a TLS offset from the stack, converts it to
2832     // an address in the current thread's thread-local storage block, and
2833     // pushes it on the stack.
2834     //----------------------------------------------------------------------
2835     case DW_OP_form_tls_address:
2836     case DW_OP_GNU_push_tls_address: {
2837       if (stack.size() < 1) {
2838         if (error_ptr) {
2839           if (op == DW_OP_form_tls_address)
2840             error_ptr->SetErrorString(
2841                 "DW_OP_form_tls_address needs an argument.");
2842           else
2843             error_ptr->SetErrorString(
2844                 "DW_OP_GNU_push_tls_address needs an argument.");
2845         }
2846         return false;
2847       }
2848 
2849       if (!exe_ctx || !module_sp) {
2850         if (error_ptr)
2851           error_ptr->SetErrorString("No context to evaluate TLS within.");
2852         return false;
2853       }
2854 
2855       Thread *thread = exe_ctx->GetThreadPtr();
2856       if (!thread) {
2857         if (error_ptr)
2858           error_ptr->SetErrorString("No thread to evaluate TLS within.");
2859         return false;
2860       }
2861 
2862       // Lookup the TLS block address for this thread and module.
2863       const addr_t tls_file_addr =
2864           stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
2865       const addr_t tls_load_addr =
2866           thread->GetThreadLocalData(module_sp, tls_file_addr);
2867 
2868       if (tls_load_addr == LLDB_INVALID_ADDRESS) {
2869         if (error_ptr)
2870           error_ptr->SetErrorString(
2871               "No TLS data currently exists for this thread.");
2872         return false;
2873       }
2874 
2875       stack.back().GetScalar() = tls_load_addr;
2876       stack.back().SetValueType(Value::eValueTypeLoadAddress);
2877     } break;
2878 
2879     //----------------------------------------------------------------------
2880     // OPCODE: DW_OP_GNU_addr_index
2881     // OPERANDS: 1
2882     //      ULEB128: index to the .debug_addr section
2883     // DESCRIPTION: Pushes an address to the stack from the .debug_addr
2884     // section with the base address specified by the DW_AT_addr_base attribute
2885     // and the 0 based index is the ULEB128 encoded index.
2886     //----------------------------------------------------------------------
2887     case DW_OP_GNU_addr_index: {
2888       if (!dwarf_cu) {
2889         if (error_ptr)
2890           error_ptr->SetErrorString("DW_OP_GNU_addr_index found without a "
2891                                     "compile unit being specified");
2892         return false;
2893       }
2894       uint64_t index = opcodes.GetULEB128(&offset);
2895       uint32_t index_size = dwarf_cu->GetAddressByteSize();
2896       dw_offset_t addr_base = dwarf_cu->GetAddrBase();
2897       lldb::offset_t offset = addr_base + index * index_size;
2898       uint64_t value =
2899           dwarf_cu->GetSymbolFileDWARF()->get_debug_addr_data().GetMaxU64(
2900               &offset, index_size);
2901       stack.push_back(Scalar(value));
2902       stack.back().SetValueType(Value::eValueTypeFileAddress);
2903     } break;
2904 
2905     //----------------------------------------------------------------------
2906     // OPCODE: DW_OP_GNU_const_index
2907     // OPERANDS: 1
2908     //      ULEB128: index to the .debug_addr section
2909     // DESCRIPTION: Pushes an constant with the size of a machine address to
2910     // the stack from the .debug_addr section with the base address specified
2911     // by the DW_AT_addr_base attribute and the 0 based index is the ULEB128
2912     // encoded index.
2913     //----------------------------------------------------------------------
2914     case DW_OP_GNU_const_index: {
2915       if (!dwarf_cu) {
2916         if (error_ptr)
2917           error_ptr->SetErrorString("DW_OP_GNU_const_index found without a "
2918                                     "compile unit being specified");
2919         return false;
2920       }
2921       uint64_t index = opcodes.GetULEB128(&offset);
2922       uint32_t index_size = dwarf_cu->GetAddressByteSize();
2923       dw_offset_t addr_base = dwarf_cu->GetAddrBase();
2924       lldb::offset_t offset = addr_base + index * index_size;
2925       const DWARFDataExtractor &debug_addr =
2926           dwarf_cu->GetSymbolFileDWARF()->get_debug_addr_data();
2927       switch (index_size) {
2928       case 4:
2929         stack.push_back(Scalar(debug_addr.GetU32(&offset)));
2930         break;
2931       case 8:
2932         stack.push_back(Scalar(debug_addr.GetU64(&offset)));
2933         break;
2934       default:
2935         assert(false && "Unhandled index size");
2936         return false;
2937       }
2938     } break;
2939 
2940     default:
2941       if (log)
2942         log->Printf("Unhandled opcode %s in DWARFExpression.",
2943                     DW_OP_value_to_name(op));
2944       break;
2945     }
2946   }
2947 
2948   if (stack.empty()) {
2949     // Nothing on the stack, check if we created a piece value from DW_OP_piece
2950     // or DW_OP_bit_piece opcodes
2951     if (pieces.GetBuffer().GetByteSize()) {
2952       result = pieces;
2953     } else {
2954       if (error_ptr)
2955         error_ptr->SetErrorString("Stack empty after evaluation.");
2956       return false;
2957     }
2958   } else {
2959     if (log && log->GetVerbose()) {
2960       size_t count = stack.size();
2961       log->Printf("Stack after operation has %" PRIu64 " values:",
2962                   (uint64_t)count);
2963       for (size_t i = 0; i < count; ++i) {
2964         StreamString new_value;
2965         new_value.Printf("[%" PRIu64 "]", (uint64_t)i);
2966         stack[i].Dump(&new_value);
2967         log->Printf("  %s", new_value.GetData());
2968       }
2969     }
2970     result = stack.back();
2971   }
2972   return true; // Return true on success
2973 }
2974 
2975 size_t DWARFExpression::LocationListSize(const DWARFUnit *dwarf_cu,
2976                                          const DataExtractor &debug_loc_data,
2977                                          lldb::offset_t offset) {
2978   const lldb::offset_t debug_loc_offset = offset;
2979   while (debug_loc_data.ValidOffset(offset)) {
2980     lldb::addr_t start_addr = LLDB_INVALID_ADDRESS;
2981     lldb::addr_t end_addr = LLDB_INVALID_ADDRESS;
2982     if (!AddressRangeForLocationListEntry(dwarf_cu, debug_loc_data, &offset,
2983                                           start_addr, end_addr))
2984       break;
2985 
2986     if (start_addr == 0 && end_addr == 0)
2987       break;
2988 
2989     uint16_t loc_length = debug_loc_data.GetU16(&offset);
2990     offset += loc_length;
2991   }
2992 
2993   if (offset > debug_loc_offset)
2994     return offset - debug_loc_offset;
2995   return 0;
2996 }
2997 
2998 bool DWARFExpression::AddressRangeForLocationListEntry(
2999     const DWARFUnit *dwarf_cu, const DataExtractor &debug_loc_data,
3000     lldb::offset_t *offset_ptr, lldb::addr_t &low_pc, lldb::addr_t &high_pc) {
3001   if (!debug_loc_data.ValidOffset(*offset_ptr))
3002     return false;
3003 
3004   switch (dwarf_cu->GetSymbolFileDWARF()->GetLocationListFormat()) {
3005   case NonLocationList:
3006     return false;
3007   case RegularLocationList:
3008     low_pc = debug_loc_data.GetAddress(offset_ptr);
3009     high_pc = debug_loc_data.GetAddress(offset_ptr);
3010     return true;
3011   case SplitDwarfLocationList:
3012     switch (debug_loc_data.GetU8(offset_ptr)) {
3013     case DW_LLE_end_of_list:
3014       return false;
3015     case DW_LLE_startx_endx: {
3016       uint64_t index = debug_loc_data.GetULEB128(offset_ptr);
3017       low_pc = ReadAddressFromDebugAddrSection(dwarf_cu, index);
3018       index = debug_loc_data.GetULEB128(offset_ptr);
3019       high_pc = ReadAddressFromDebugAddrSection(dwarf_cu, index);
3020       return true;
3021     }
3022     case DW_LLE_startx_length: {
3023       uint64_t index = debug_loc_data.GetULEB128(offset_ptr);
3024       low_pc = ReadAddressFromDebugAddrSection(dwarf_cu, index);
3025       uint32_t length = debug_loc_data.GetU32(offset_ptr);
3026       high_pc = low_pc + length;
3027       return true;
3028     }
3029     default:
3030       // Not supported entry type
3031       return false;
3032     }
3033   }
3034   assert(false && "Not supported location list type");
3035   return false;
3036 }
3037 
3038 static bool print_dwarf_exp_op(Stream &s, const DataExtractor &data,
3039                                lldb::offset_t *offset_ptr, int address_size,
3040                                int dwarf_ref_size) {
3041   uint8_t opcode = data.GetU8(offset_ptr);
3042   DRC_class opcode_class;
3043   uint64_t uint;
3044   int64_t sint;
3045 
3046   int size;
3047 
3048   opcode_class = DW_OP_value_to_class(opcode) & (~DRC_DWARFv3);
3049 
3050   s.Printf("%s ", DW_OP_value_to_name(opcode));
3051 
3052   /* Does this take zero parameters?  If so we can shortcut this function.  */
3053   if (opcode_class == DRC_ZEROOPERANDS)
3054     return true;
3055 
3056   if (opcode_class == DRC_TWOOPERANDS && opcode == DW_OP_bregx) {
3057     uint = data.GetULEB128(offset_ptr);
3058     sint = data.GetSLEB128(offset_ptr);
3059     s.Printf("%" PRIu64 " %" PRIi64, uint, sint);
3060     return true;
3061   }
3062   if (opcode_class != DRC_ONEOPERAND) {
3063     s.Printf("UNKNOWN OP %u", opcode);
3064     return false;
3065   }
3066 
3067   switch (opcode) {
3068   case DW_OP_addr:
3069     size = address_size;
3070     break;
3071   case DW_OP_const1u:
3072     size = 1;
3073     break;
3074   case DW_OP_const1s:
3075     size = -1;
3076     break;
3077   case DW_OP_const2u:
3078     size = 2;
3079     break;
3080   case DW_OP_const2s:
3081     size = -2;
3082     break;
3083   case DW_OP_const4u:
3084     size = 4;
3085     break;
3086   case DW_OP_const4s:
3087     size = -4;
3088     break;
3089   case DW_OP_const8u:
3090     size = 8;
3091     break;
3092   case DW_OP_const8s:
3093     size = -8;
3094     break;
3095   case DW_OP_constu:
3096     size = 128;
3097     break;
3098   case DW_OP_consts:
3099     size = -128;
3100     break;
3101   case DW_OP_fbreg:
3102     size = -128;
3103     break;
3104   case DW_OP_breg0:
3105   case DW_OP_breg1:
3106   case DW_OP_breg2:
3107   case DW_OP_breg3:
3108   case DW_OP_breg4:
3109   case DW_OP_breg5:
3110   case DW_OP_breg6:
3111   case DW_OP_breg7:
3112   case DW_OP_breg8:
3113   case DW_OP_breg9:
3114   case DW_OP_breg10:
3115   case DW_OP_breg11:
3116   case DW_OP_breg12:
3117   case DW_OP_breg13:
3118   case DW_OP_breg14:
3119   case DW_OP_breg15:
3120   case DW_OP_breg16:
3121   case DW_OP_breg17:
3122   case DW_OP_breg18:
3123   case DW_OP_breg19:
3124   case DW_OP_breg20:
3125   case DW_OP_breg21:
3126   case DW_OP_breg22:
3127   case DW_OP_breg23:
3128   case DW_OP_breg24:
3129   case DW_OP_breg25:
3130   case DW_OP_breg26:
3131   case DW_OP_breg27:
3132   case DW_OP_breg28:
3133   case DW_OP_breg29:
3134   case DW_OP_breg30:
3135   case DW_OP_breg31:
3136     size = -128;
3137     break;
3138   case DW_OP_pick:
3139   case DW_OP_deref_size:
3140   case DW_OP_xderef_size:
3141     size = 1;
3142     break;
3143   case DW_OP_skip:
3144   case DW_OP_bra:
3145     size = -2;
3146     break;
3147   case DW_OP_call2:
3148     size = 2;
3149     break;
3150   case DW_OP_call4:
3151     size = 4;
3152     break;
3153   case DW_OP_call_ref:
3154     size = dwarf_ref_size;
3155     break;
3156   case DW_OP_piece:
3157   case DW_OP_plus_uconst:
3158   case DW_OP_regx:
3159   case DW_OP_GNU_addr_index:
3160   case DW_OP_GNU_const_index:
3161     size = 128;
3162     break;
3163   default:
3164     s.Printf("UNKNOWN ONE-OPERAND OPCODE, #%u", opcode);
3165     return true;
3166   }
3167 
3168   switch (size) {
3169   case -1:
3170     sint = (int8_t)data.GetU8(offset_ptr);
3171     s.Printf("%+" PRIi64, sint);
3172     break;
3173   case -2:
3174     sint = (int16_t)data.GetU16(offset_ptr);
3175     s.Printf("%+" PRIi64, sint);
3176     break;
3177   case -4:
3178     sint = (int32_t)data.GetU32(offset_ptr);
3179     s.Printf("%+" PRIi64, sint);
3180     break;
3181   case -8:
3182     sint = (int64_t)data.GetU64(offset_ptr);
3183     s.Printf("%+" PRIi64, sint);
3184     break;
3185   case -128:
3186     sint = data.GetSLEB128(offset_ptr);
3187     s.Printf("%+" PRIi64, sint);
3188     break;
3189   case 1:
3190     uint = data.GetU8(offset_ptr);
3191     s.Printf("0x%2.2" PRIx64, uint);
3192     break;
3193   case 2:
3194     uint = data.GetU16(offset_ptr);
3195     s.Printf("0x%4.4" PRIx64, uint);
3196     break;
3197   case 4:
3198     uint = data.GetU32(offset_ptr);
3199     s.Printf("0x%8.8" PRIx64, uint);
3200     break;
3201   case 8:
3202     uint = data.GetU64(offset_ptr);
3203     s.Printf("0x%16.16" PRIx64, uint);
3204     break;
3205   case 128:
3206     uint = data.GetULEB128(offset_ptr);
3207     s.Printf("0x%" PRIx64, uint);
3208     break;
3209   }
3210 
3211   return false;
3212 }
3213 
3214 bool DWARFExpression::PrintDWARFExpression(Stream &s, const DataExtractor &data,
3215                                            int address_size, int dwarf_ref_size,
3216                                            bool location_expression) {
3217   int op_count = 0;
3218   lldb::offset_t offset = 0;
3219   while (data.ValidOffset(offset)) {
3220     if (location_expression && op_count > 0)
3221       return false;
3222     if (op_count > 0)
3223       s.PutCString(", ");
3224     if (!print_dwarf_exp_op(s, data, &offset, address_size, dwarf_ref_size))
3225       return false;
3226     op_count++;
3227   }
3228 
3229   return true;
3230 }
3231 
3232 void DWARFExpression::PrintDWARFLocationList(
3233     Stream &s, const DWARFUnit *cu, const DataExtractor &debug_loc_data,
3234     lldb::offset_t offset) {
3235   uint64_t start_addr, end_addr;
3236   uint32_t addr_size = DWARFUnit::GetAddressByteSize(cu);
3237   s.SetAddressByteSize(DWARFUnit::GetAddressByteSize(cu));
3238   dw_addr_t base_addr = cu ? cu->GetBaseAddress() : 0;
3239   while (debug_loc_data.ValidOffset(offset)) {
3240     start_addr = debug_loc_data.GetMaxU64(&offset, addr_size);
3241     end_addr = debug_loc_data.GetMaxU64(&offset, addr_size);
3242 
3243     if (start_addr == 0 && end_addr == 0)
3244       break;
3245 
3246     s.PutCString("\n            ");
3247     s.Indent();
3248     if (cu)
3249       s.AddressRange(start_addr + base_addr, end_addr + base_addr,
3250                      cu->GetAddressByteSize(), NULL, ": ");
3251     uint32_t loc_length = debug_loc_data.GetU16(&offset);
3252 
3253     DataExtractor locationData(debug_loc_data, offset, loc_length);
3254     PrintDWARFExpression(s, locationData, addr_size, 4, false);
3255     offset += loc_length;
3256   }
3257 }
3258 
3259 bool DWARFExpression::GetOpAndEndOffsets(StackFrame &frame,
3260                                          lldb::offset_t &op_offset,
3261                                          lldb::offset_t &end_offset) {
3262   SymbolContext sc = frame.GetSymbolContext(eSymbolContextFunction);
3263   if (!sc.function) {
3264     return false;
3265   }
3266 
3267   addr_t loclist_base_file_addr =
3268       sc.function->GetAddressRange().GetBaseAddress().GetFileAddress();
3269   if (loclist_base_file_addr == LLDB_INVALID_ADDRESS) {
3270     return false;
3271   }
3272 
3273   addr_t pc_file_addr = frame.GetFrameCodeAddress().GetFileAddress();
3274   lldb::offset_t opcodes_offset, opcodes_length;
3275   if (!GetLocation(loclist_base_file_addr, pc_file_addr, opcodes_offset,
3276                    opcodes_length)) {
3277     return false;
3278   }
3279 
3280   if (opcodes_length == 0) {
3281     return false;
3282   }
3283 
3284   op_offset = opcodes_offset;
3285   end_offset = opcodes_offset + opcodes_length;
3286   return true;
3287 }
3288 
3289 bool DWARFExpression::MatchesOperand(StackFrame &frame,
3290                                      const Instruction::Operand &operand) {
3291   using namespace OperandMatchers;
3292 
3293   lldb::offset_t op_offset;
3294   lldb::offset_t end_offset;
3295   if (!GetOpAndEndOffsets(frame, op_offset, end_offset)) {
3296     return false;
3297   }
3298 
3299   if (!m_data.ValidOffset(op_offset) || op_offset >= end_offset) {
3300     return false;
3301   }
3302 
3303   RegisterContextSP reg_ctx_sp = frame.GetRegisterContext();
3304   if (!reg_ctx_sp) {
3305     return false;
3306   }
3307 
3308   DataExtractor opcodes = m_data;
3309   uint8_t opcode = opcodes.GetU8(&op_offset);
3310 
3311   if (opcode == DW_OP_fbreg) {
3312     int64_t offset = opcodes.GetSLEB128(&op_offset);
3313 
3314     DWARFExpression *fb_expr = frame.GetFrameBaseExpression(nullptr);
3315     if (!fb_expr) {
3316       return false;
3317     }
3318 
3319     auto recurse = [&frame, fb_expr](const Instruction::Operand &child) {
3320       return fb_expr->MatchesOperand(frame, child);
3321     };
3322 
3323     if (!offset &&
3324         MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference),
3325                      recurse)(operand)) {
3326       return true;
3327     }
3328 
3329     return MatchUnaryOp(
3330         MatchOpType(Instruction::Operand::Type::Dereference),
3331         MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum),
3332                       MatchImmOp(offset), recurse))(operand);
3333   }
3334 
3335   bool dereference = false;
3336   const RegisterInfo *reg = nullptr;
3337   int64_t offset = 0;
3338 
3339   if (opcode >= DW_OP_reg0 && opcode <= DW_OP_reg31) {
3340     reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_reg0);
3341   } else if (opcode >= DW_OP_breg0 && opcode <= DW_OP_breg31) {
3342     offset = opcodes.GetSLEB128(&op_offset);
3343     reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, opcode - DW_OP_breg0);
3344   } else if (opcode == DW_OP_regx) {
3345     uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset));
3346     reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num);
3347   } else if (opcode == DW_OP_bregx) {
3348     uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(&op_offset));
3349     offset = opcodes.GetSLEB128(&op_offset);
3350     reg = reg_ctx_sp->GetRegisterInfo(m_reg_kind, reg_num);
3351   } else {
3352     return false;
3353   }
3354 
3355   if (!reg) {
3356     return false;
3357   }
3358 
3359   if (dereference) {
3360     if (!offset &&
3361         MatchUnaryOp(MatchOpType(Instruction::Operand::Type::Dereference),
3362                      MatchRegOp(*reg))(operand)) {
3363       return true;
3364     }
3365 
3366     return MatchUnaryOp(
3367         MatchOpType(Instruction::Operand::Type::Dereference),
3368         MatchBinaryOp(MatchOpType(Instruction::Operand::Type::Sum),
3369                       MatchRegOp(*reg),
3370                       MatchImmOp(offset)))(operand);
3371   } else {
3372     return MatchRegOp(*reg)(operand);
3373   }
3374 }
3375 
3376