1 //===-- DWARFDebugInfoEntry.cpp ---------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "DWARFDebugInfoEntry.h"
10 
11 #include <assert.h>
12 
13 #include <algorithm>
14 
15 #include "lldb/Core/Module.h"
16 #include "lldb/Expression/DWARFExpression.h"
17 #include "lldb/Symbol/ObjectFile.h"
18 #include "lldb/Utility/Stream.h"
19 
20 #include "DWARFUnit.h"
21 #include "DWARFDebugAbbrev.h"
22 #include "DWARFDebugAranges.h"
23 #include "DWARFDebugInfo.h"
24 #include "DWARFDebugRanges.h"
25 #include "DWARFDeclContext.h"
26 #include "DWARFFormValue.h"
27 #include "SymbolFileDWARF.h"
28 #include "SymbolFileDWARFDwo.h"
29 
30 using namespace lldb_private;
31 using namespace std;
32 extern int g_verbose;
33 
34 bool DWARFDebugInfoEntry::FastExtract(
35     const DWARFDataExtractor &debug_info_data, const DWARFUnit *cu,
36     lldb::offset_t *offset_ptr) {
37   m_offset = *offset_ptr;
38   m_parent_idx = 0;
39   m_sibling_idx = 0;
40   const uint64_t abbr_idx = debug_info_data.GetULEB128(offset_ptr);
41   lldbassert(abbr_idx <= UINT16_MAX);
42   m_abbr_idx = abbr_idx;
43 
44   // assert (fixed_form_sizes);  // For best performance this should be
45   // specified!
46 
47   if (m_abbr_idx) {
48     lldb::offset_t offset = *offset_ptr;
49 
50     const DWARFAbbreviationDeclaration *abbrevDecl =
51         cu->GetAbbreviations()->GetAbbreviationDeclaration(m_abbr_idx);
52 
53     if (abbrevDecl == nullptr) {
54       cu->GetSymbolFileDWARF()->GetObjectFile()->GetModule()->ReportError(
55           "{0x%8.8x}: invalid abbreviation code %u, please file a bug and "
56           "attach the file at the start of this error message",
57           m_offset, (unsigned)abbr_idx);
58       // WE can't parse anymore if the DWARF is borked...
59       *offset_ptr = UINT32_MAX;
60       return false;
61     }
62     m_tag = abbrevDecl->Tag();
63     m_has_children = abbrevDecl->HasChildren();
64     // Skip all data in the .debug_info for the attributes
65     const uint32_t numAttributes = abbrevDecl->NumAttributes();
66     uint32_t i;
67     dw_form_t form;
68     for (i = 0; i < numAttributes; ++i) {
69       form = abbrevDecl->GetFormByIndexUnchecked(i);
70 
71       llvm::Optional<uint8_t> fixed_skip_size = DWARFFormValue::GetFixedSize(form, cu);
72       if (fixed_skip_size)
73         offset += *fixed_skip_size;
74       else {
75         bool form_is_indirect = false;
76         do {
77           form_is_indirect = false;
78           uint32_t form_size = 0;
79           switch (form) {
80           // Blocks if inlined data that have a length field and the data bytes
81           // inlined in the .debug_info
82           case DW_FORM_exprloc:
83           case DW_FORM_block:
84             form_size = debug_info_data.GetULEB128(&offset);
85             break;
86           case DW_FORM_block1:
87             form_size = debug_info_data.GetU8_unchecked(&offset);
88             break;
89           case DW_FORM_block2:
90             form_size = debug_info_data.GetU16_unchecked(&offset);
91             break;
92           case DW_FORM_block4:
93             form_size = debug_info_data.GetU32_unchecked(&offset);
94             break;
95 
96           // Inlined NULL terminated C-strings
97           case DW_FORM_string:
98             debug_info_data.GetCStr(&offset);
99             break;
100 
101           // Compile unit address sized values
102           case DW_FORM_addr:
103             form_size = cu->GetAddressByteSize();
104             break;
105           case DW_FORM_ref_addr:
106             if (cu->GetVersion() <= 2)
107               form_size = cu->GetAddressByteSize();
108             else
109               form_size = 4;
110             break;
111 
112           // 0 sized form
113           case DW_FORM_flag_present:
114             form_size = 0;
115             break;
116 
117           // 1 byte values
118           case DW_FORM_addrx1:
119           case DW_FORM_data1:
120           case DW_FORM_flag:
121           case DW_FORM_ref1:
122           case DW_FORM_strx1:
123             form_size = 1;
124             break;
125 
126           // 2 byte values
127           case DW_FORM_addrx2:
128           case DW_FORM_data2:
129           case DW_FORM_ref2:
130           case DW_FORM_strx2:
131             form_size = 2;
132             break;
133 
134           // 3 byte values
135           case DW_FORM_addrx3:
136           case DW_FORM_strx3:
137             form_size = 3;
138             break;
139 
140           // 4 byte values
141           case DW_FORM_addrx4:
142           case DW_FORM_data4:
143           case DW_FORM_ref4:
144           case DW_FORM_strx4:
145             form_size = 4;
146             break;
147 
148           // 8 byte values
149           case DW_FORM_data8:
150           case DW_FORM_ref8:
151           case DW_FORM_ref_sig8:
152             form_size = 8;
153             break;
154 
155           // signed or unsigned LEB 128 values
156           case DW_FORM_addrx:
157           case DW_FORM_rnglistx:
158           case DW_FORM_sdata:
159           case DW_FORM_udata:
160           case DW_FORM_ref_udata:
161           case DW_FORM_GNU_addr_index:
162           case DW_FORM_GNU_str_index:
163           case DW_FORM_strx:
164             debug_info_data.Skip_LEB128(&offset);
165             break;
166 
167           case DW_FORM_indirect:
168             form_is_indirect = true;
169             form = debug_info_data.GetULEB128(&offset);
170             break;
171 
172           case DW_FORM_strp:
173           case DW_FORM_sec_offset:
174             debug_info_data.GetU32(&offset);
175             break;
176 
177           case DW_FORM_implicit_const:
178             form_size = 0;
179             break;
180 
181           default:
182             *offset_ptr = m_offset;
183             return false;
184           }
185           offset += form_size;
186 
187         } while (form_is_indirect);
188       }
189     }
190     *offset_ptr = offset;
191     return true;
192   } else {
193     m_tag = 0;
194     m_has_children = false;
195     return true; // NULL debug tag entry
196   }
197 
198   return false;
199 }
200 
201 // Extract
202 //
203 // Extract a debug info entry for a given compile unit from the .debug_info and
204 // .debug_abbrev data within the SymbolFileDWARF class starting at the given
205 // offset
206 bool DWARFDebugInfoEntry::Extract(const DWARFUnit *cu,
207                                   lldb::offset_t *offset_ptr) {
208   const DWARFDataExtractor &debug_info_data = cu->GetData();
209   //    const DWARFDataExtractor& debug_str_data =
210   //    dwarf2Data->get_debug_str_data();
211   const uint32_t cu_end_offset = cu->GetNextUnitOffset();
212   lldb::offset_t offset = *offset_ptr;
213   //  if (offset >= cu_end_offset)
214   //      Log::Status("DIE at offset 0x%8.8x is beyond the end of the current
215   //      compile unit (0x%8.8x)", m_offset, cu_end_offset);
216   if ((offset < cu_end_offset) && debug_info_data.ValidOffset(offset)) {
217     m_offset = offset;
218 
219     const uint64_t abbr_idx = debug_info_data.GetULEB128(&offset);
220     lldbassert(abbr_idx <= UINT16_MAX);
221     m_abbr_idx = abbr_idx;
222     if (abbr_idx) {
223       const DWARFAbbreviationDeclaration *abbrevDecl =
224           cu->GetAbbreviations()->GetAbbreviationDeclaration(abbr_idx);
225 
226       if (abbrevDecl) {
227         m_tag = abbrevDecl->Tag();
228         m_has_children = abbrevDecl->HasChildren();
229 
230         bool isCompileUnitTag = (m_tag == DW_TAG_compile_unit ||
231                                  m_tag == DW_TAG_partial_unit);
232         if (cu && isCompileUnitTag)
233           const_cast<DWARFUnit *>(cu)->SetBaseAddress(0);
234 
235         // Skip all data in the .debug_info for the attributes
236         const uint32_t numAttributes = abbrevDecl->NumAttributes();
237         for (uint32_t i = 0; i < numAttributes; ++i) {
238           DWARFFormValue form_value(cu);
239           dw_attr_t attr;
240           abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
241           dw_form_t form = form_value.Form();
242 
243           if (isCompileUnitTag &&
244               ((attr == DW_AT_entry_pc) || (attr == DW_AT_low_pc))) {
245             if (form_value.ExtractValue(debug_info_data, &offset)) {
246               if (attr == DW_AT_low_pc || attr == DW_AT_entry_pc)
247                 const_cast<DWARFUnit *>(cu)->SetBaseAddress(
248                     form_value.Address());
249             }
250           } else {
251             bool form_is_indirect = false;
252             do {
253               form_is_indirect = false;
254               uint32_t form_size = 0;
255               switch (form) {
256               // Blocks if inlined data that have a length field and the data
257               // bytes inlined in the .debug_info
258               case DW_FORM_exprloc:
259               case DW_FORM_block:
260                 form_size = debug_info_data.GetULEB128(&offset);
261                 break;
262               case DW_FORM_block1:
263                 form_size = debug_info_data.GetU8(&offset);
264                 break;
265               case DW_FORM_block2:
266                 form_size = debug_info_data.GetU16(&offset);
267                 break;
268               case DW_FORM_block4:
269                 form_size = debug_info_data.GetU32(&offset);
270                 break;
271 
272               // Inlined NULL terminated C-strings
273               case DW_FORM_string:
274                 debug_info_data.GetCStr(&offset);
275                 break;
276 
277               // Compile unit address sized values
278               case DW_FORM_addr:
279                 form_size = cu->GetAddressByteSize();
280                 break;
281               case DW_FORM_ref_addr:
282                 if (cu->GetVersion() <= 2)
283                   form_size = cu->GetAddressByteSize();
284                 else
285                   form_size = 4;
286                 break;
287 
288               // 0 sized form
289               case DW_FORM_flag_present:
290               case DW_FORM_implicit_const:
291                 form_size = 0;
292                 break;
293 
294               // 1 byte values
295               case DW_FORM_data1:
296               case DW_FORM_flag:
297               case DW_FORM_ref1:
298                 form_size = 1;
299                 break;
300 
301               // 2 byte values
302               case DW_FORM_data2:
303               case DW_FORM_ref2:
304                 form_size = 2;
305                 break;
306 
307               // 4 byte values
308               case DW_FORM_data4:
309               case DW_FORM_ref4:
310                 form_size = 4;
311                 break;
312 
313               // 8 byte values
314               case DW_FORM_data8:
315               case DW_FORM_ref8:
316               case DW_FORM_ref_sig8:
317                 form_size = 8;
318                 break;
319 
320               // signed or unsigned LEB 128 values
321               case DW_FORM_addrx:
322               case DW_FORM_sdata:
323               case DW_FORM_udata:
324               case DW_FORM_ref_udata:
325               case DW_FORM_GNU_addr_index:
326               case DW_FORM_GNU_str_index:
327                 debug_info_data.Skip_LEB128(&offset);
328                 break;
329 
330               case DW_FORM_indirect:
331                 form = debug_info_data.GetULEB128(&offset);
332                 form_is_indirect = true;
333                 break;
334 
335               case DW_FORM_strp:
336               case DW_FORM_sec_offset:
337                 debug_info_data.GetU32(&offset);
338                 break;
339 
340               default:
341                 *offset_ptr = offset;
342                 return false;
343               }
344 
345               offset += form_size;
346             } while (form_is_indirect);
347           }
348         }
349         *offset_ptr = offset;
350         return true;
351       }
352     } else {
353       m_tag = 0;
354       m_has_children = false;
355       *offset_ptr = offset;
356       return true; // NULL debug tag entry
357     }
358   }
359 
360   return false;
361 }
362 
363 static DWARFRangeList GetRangesOrReportError(const DWARFUnit &unit,
364                                              const DWARFDebugInfoEntry &die,
365                                              const DWARFFormValue &value) {
366   llvm::Expected<DWARFRangeList> expected_ranges =
367       (value.Form() == DW_FORM_rnglistx)
368           ? unit.FindRnglistFromIndex(value.Unsigned())
369           : unit.FindRnglistFromOffset(value.Unsigned());
370   if (expected_ranges)
371     return std::move(*expected_ranges);
372   unit.GetSymbolFileDWARF()->GetObjectFile()->GetModule()->ReportError(
373       "{0x%8.8x}: DIE has DW_AT_ranges(0x%" PRIx64 ") attribute, but "
374       "range extraction failed (%s), please file a bug "
375       "and attach the file at the start of this error message",
376       die.GetOffset(), value.Unsigned(),
377       toString(expected_ranges.takeError()).c_str());
378   return DWARFRangeList();
379 }
380 
381 // GetDIENamesAndRanges
382 //
383 // Gets the valid address ranges for a given DIE by looking for a
384 // DW_AT_low_pc/DW_AT_high_pc pair, DW_AT_entry_pc, or DW_AT_ranges attributes.
385 bool DWARFDebugInfoEntry::GetDIENamesAndRanges(
386     const DWARFUnit *cu, const char *&name, const char *&mangled,
387     DWARFRangeList &ranges, int &decl_file, int &decl_line, int &decl_column,
388     int &call_file, int &call_line, int &call_column,
389     DWARFExpression *frame_base) const {
390   SymbolFileDWARFDwo *dwo_symbol_file = cu->GetDwoSymbolFile();
391   if (dwo_symbol_file)
392     return GetDIENamesAndRanges(
393         dwo_symbol_file->GetCompileUnit(), name, mangled, ranges, decl_file,
394         decl_line, decl_column, call_file, call_line, call_column, frame_base);
395 
396   dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
397   dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
398   std::vector<DIERef> die_refs;
399   bool set_frame_base_loclist_addr = false;
400 
401   lldb::offset_t offset;
402   const DWARFAbbreviationDeclaration *abbrevDecl =
403       GetAbbreviationDeclarationPtr(cu, offset);
404 
405   SymbolFileDWARF *dwarf2Data = cu->GetSymbolFileDWARF();
406   lldb::ModuleSP module = dwarf2Data->GetObjectFile()->GetModule();
407 
408   if (abbrevDecl) {
409     const DWARFDataExtractor &debug_info_data = cu->GetData();
410 
411     if (!debug_info_data.ValidOffset(offset))
412       return false;
413 
414     const uint32_t numAttributes = abbrevDecl->NumAttributes();
415     bool do_offset = false;
416 
417     for (uint32_t i = 0; i < numAttributes; ++i) {
418       DWARFFormValue form_value(cu);
419       dw_attr_t attr;
420       abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
421 
422       if (form_value.ExtractValue(debug_info_data, &offset)) {
423         switch (attr) {
424         case DW_AT_low_pc:
425           lo_pc = form_value.Address();
426 
427           if (do_offset)
428             hi_pc += lo_pc;
429           do_offset = false;
430           break;
431 
432         case DW_AT_entry_pc:
433           lo_pc = form_value.Address();
434           break;
435 
436         case DW_AT_high_pc:
437           if (form_value.Form() == DW_FORM_addr ||
438               form_value.Form() == DW_FORM_addrx ||
439               form_value.Form() == DW_FORM_GNU_addr_index) {
440             hi_pc = form_value.Address();
441           } else {
442             hi_pc = form_value.Unsigned();
443             if (lo_pc == LLDB_INVALID_ADDRESS)
444               do_offset = hi_pc != LLDB_INVALID_ADDRESS;
445             else
446               hi_pc += lo_pc; // DWARF 4 introduces <offset-from-lo-pc> to save
447                               // on relocations
448           }
449           break;
450 
451         case DW_AT_ranges:
452           ranges = GetRangesOrReportError(*cu, *this, form_value);
453           break;
454 
455         case DW_AT_name:
456           if (name == nullptr)
457             name = form_value.AsCString();
458           break;
459 
460         case DW_AT_MIPS_linkage_name:
461         case DW_AT_linkage_name:
462           if (mangled == nullptr)
463             mangled = form_value.AsCString();
464           break;
465 
466         case DW_AT_abstract_origin:
467           die_refs.emplace_back(form_value);
468           break;
469 
470         case DW_AT_specification:
471           die_refs.emplace_back(form_value);
472           break;
473 
474         case DW_AT_decl_file:
475           if (decl_file == 0)
476             decl_file = form_value.Unsigned();
477           break;
478 
479         case DW_AT_decl_line:
480           if (decl_line == 0)
481             decl_line = form_value.Unsigned();
482           break;
483 
484         case DW_AT_decl_column:
485           if (decl_column == 0)
486             decl_column = form_value.Unsigned();
487           break;
488 
489         case DW_AT_call_file:
490           if (call_file == 0)
491             call_file = form_value.Unsigned();
492           break;
493 
494         case DW_AT_call_line:
495           if (call_line == 0)
496             call_line = form_value.Unsigned();
497           break;
498 
499         case DW_AT_call_column:
500           if (call_column == 0)
501             call_column = form_value.Unsigned();
502           break;
503 
504         case DW_AT_frame_base:
505           if (frame_base) {
506             if (form_value.BlockData()) {
507               uint32_t block_offset =
508                   form_value.BlockData() - debug_info_data.GetDataStart();
509               uint32_t block_length = form_value.Unsigned();
510               *frame_base = DWARFExpression(module, debug_info_data, cu,
511                                             block_offset, block_length);
512             } else {
513               const DWARFDataExtractor &debug_loc_data =
514                   dwarf2Data->DebugLocData();
515               const dw_offset_t debug_loc_offset = form_value.Unsigned();
516 
517               size_t loc_list_length = DWARFExpression::LocationListSize(
518                   cu, debug_loc_data, debug_loc_offset);
519               if (loc_list_length > 0) {
520                 *frame_base =
521                     DWARFExpression(module, debug_loc_data, cu,
522                                     debug_loc_offset, loc_list_length);
523                 if (lo_pc != LLDB_INVALID_ADDRESS) {
524                   assert(lo_pc >= cu->GetBaseAddress());
525                   frame_base->SetLocationListSlide(lo_pc -
526                                                    cu->GetBaseAddress());
527                 } else {
528                   set_frame_base_loclist_addr = true;
529                 }
530               }
531             }
532           }
533           break;
534 
535         default:
536           break;
537         }
538       }
539     }
540   }
541 
542   if (ranges.IsEmpty()) {
543     if (lo_pc != LLDB_INVALID_ADDRESS) {
544       if (hi_pc != LLDB_INVALID_ADDRESS && hi_pc > lo_pc)
545         ranges.Append(DWARFRangeList::Entry(lo_pc, hi_pc - lo_pc));
546       else
547         ranges.Append(DWARFRangeList::Entry(lo_pc, 0));
548     }
549   }
550 
551   if (set_frame_base_loclist_addr) {
552     dw_addr_t lowest_range_pc = ranges.GetMinRangeBase(0);
553     assert(lowest_range_pc >= cu->GetBaseAddress());
554     frame_base->SetLocationListSlide(lowest_range_pc - cu->GetBaseAddress());
555   }
556 
557   if (ranges.IsEmpty() || name == nullptr || mangled == nullptr) {
558     for (const DIERef &die_ref : die_refs) {
559       if (die_ref.die_offset != DW_INVALID_OFFSET) {
560         DWARFDIE die = dwarf2Data->GetDIE(die_ref);
561         if (die)
562           die.GetDIE()->GetDIENamesAndRanges(die.GetCU(), name, mangled, ranges,
563                                              decl_file, decl_line, decl_column,
564                                              call_file, call_line, call_column);
565       }
566     }
567   }
568   return !ranges.IsEmpty();
569 }
570 
571 // Dump
572 //
573 // Dumps a debug information entry and all of it's attributes to the specified
574 // stream.
575 void DWARFDebugInfoEntry::Dump(const DWARFUnit *cu, Stream &s,
576                                uint32_t recurse_depth) const {
577   const DWARFDataExtractor &debug_info_data = cu->GetData();
578   lldb::offset_t offset = m_offset;
579 
580   if (debug_info_data.ValidOffset(offset)) {
581     dw_uleb128_t abbrCode = debug_info_data.GetULEB128(&offset);
582 
583     s.Printf("\n0x%8.8x: ", m_offset);
584     s.Indent();
585     if (abbrCode != m_abbr_idx) {
586       s.Printf("error: DWARF has been modified\n");
587     } else if (abbrCode) {
588       const DWARFAbbreviationDeclaration *abbrevDecl =
589           cu->GetAbbreviations()->GetAbbreviationDeclaration(abbrCode);
590 
591       if (abbrevDecl) {
592         s.PutCString(DW_TAG_value_to_name(abbrevDecl->Tag()));
593         s.Printf(" [%u] %c\n", abbrCode, abbrevDecl->HasChildren() ? '*' : ' ');
594 
595         // Dump all data in the .debug_info for the attributes
596         const uint32_t numAttributes = abbrevDecl->NumAttributes();
597         for (uint32_t i = 0; i < numAttributes; ++i) {
598           DWARFFormValue form_value(cu);
599           dw_attr_t attr;
600           abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
601 
602           DumpAttribute(cu, debug_info_data, &offset, s, attr, form_value);
603         }
604 
605         const DWARFDebugInfoEntry *child = GetFirstChild();
606         if (recurse_depth > 0 && child) {
607           s.IndentMore();
608 
609           while (child) {
610             child->Dump(cu, s, recurse_depth - 1);
611             child = child->GetSibling();
612           }
613           s.IndentLess();
614         }
615       } else
616         s.Printf("Abbreviation code note found in 'debug_abbrev' class for "
617                  "code: %u\n",
618                  abbrCode);
619     } else {
620       s.Printf("NULL\n");
621     }
622   }
623 }
624 
625 // DumpAttribute
626 //
627 // Dumps a debug information entry attribute along with it's form. Any special
628 // display of attributes is done (disassemble location lists, show enumeration
629 // values for attributes, etc).
630 void DWARFDebugInfoEntry::DumpAttribute(
631     const DWARFUnit *cu, const DWARFDataExtractor &debug_info_data,
632     lldb::offset_t *offset_ptr, Stream &s, dw_attr_t attr,
633     DWARFFormValue &form_value) {
634   bool show_form = s.GetFlags().Test(DWARFDebugInfo::eDumpFlag_ShowForm);
635 
636   s.Printf("            ");
637   s.Indent(DW_AT_value_to_name(attr));
638 
639   if (show_form) {
640     s.Printf("[%s", DW_FORM_value_to_name(form_value.Form()));
641   }
642 
643   if (!form_value.ExtractValue(debug_info_data, offset_ptr))
644     return;
645 
646   if (show_form) {
647     if (form_value.Form() == DW_FORM_indirect) {
648       s.Printf(" [%s]", DW_FORM_value_to_name(form_value.Form()));
649     }
650 
651     s.PutCString("] ");
652   }
653 
654   s.PutCString("( ");
655 
656   SymbolFileDWARF *dwarf2Data = cu->GetSymbolFileDWARF();
657 
658   // Check to see if we have any special attribute formatters
659   switch (attr) {
660   case DW_AT_stmt_list:
661     s.Printf("0x%8.8" PRIx64, form_value.Unsigned());
662     break;
663 
664   case DW_AT_language:
665     s.PutCString(DW_LANG_value_to_name(form_value.Unsigned()));
666     break;
667 
668   case DW_AT_encoding:
669     s.PutCString(DW_ATE_value_to_name(form_value.Unsigned()));
670     break;
671 
672   case DW_AT_frame_base:
673   case DW_AT_location:
674   case DW_AT_data_member_location: {
675     const uint8_t *blockData = form_value.BlockData();
676     if (blockData) {
677       // Location description is inlined in data in the form value
678       DWARFDataExtractor locationData(debug_info_data,
679                                       (*offset_ptr) - form_value.Unsigned(),
680                                       form_value.Unsigned());
681       DWARFExpression::PrintDWARFExpression(
682           s, locationData, DWARFUnit::GetAddressByteSize(cu), 4, false);
683     } else {
684       // We have a location list offset as the value that is the offset into
685       // the .debug_loc section that describes the value over it's lifetime
686       uint64_t debug_loc_offset = form_value.Unsigned();
687       if (dwarf2Data) {
688         DWARFExpression::PrintDWARFLocationList(
689             s, cu, dwarf2Data->DebugLocData(), debug_loc_offset);
690       }
691     }
692   } break;
693 
694   case DW_AT_abstract_origin:
695   case DW_AT_specification: {
696     DWARFDIE abstract_die = form_value.Reference();
697     form_value.Dump(s);
698     //  *ostrm_ptr << HEX32 << abstract_die.GetOffset() << " ( ";
699     abstract_die.GetName(s);
700   } break;
701 
702   case DW_AT_type: {
703     DWARFDIE type_die = form_value.Reference();
704     s.PutCString(" ( ");
705     type_die.AppendTypeName(s);
706     s.PutCString(" )");
707   } break;
708 
709   default:
710     break;
711   }
712 
713   s.PutCString(" )\n");
714 }
715 
716 // Get all attribute values for a given DIE, including following any
717 // specification or abstract origin attributes and including those in the
718 // results. Any duplicate attributes will have the first instance take
719 // precedence (this can happen for declaration attributes).
720 size_t DWARFDebugInfoEntry::GetAttributes(
721     const DWARFUnit *cu, DWARFAttributes &attributes,
722     uint32_t curr_depth) const {
723   const DWARFAbbreviationDeclaration *abbrevDecl = nullptr;
724   lldb::offset_t offset = 0;
725   if (cu)
726     abbrevDecl = GetAbbreviationDeclarationPtr(cu, offset);
727 
728   if (abbrevDecl) {
729     const DWARFDataExtractor &debug_info_data = cu->GetData();
730 
731     const uint32_t num_attributes = abbrevDecl->NumAttributes();
732     for (uint32_t i = 0; i < num_attributes; ++i) {
733       DWARFFormValue form_value(cu);
734       dw_attr_t attr;
735       abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
736       const dw_form_t form = form_value.Form();
737 
738       // If we are tracking down DW_AT_specification or DW_AT_abstract_origin
739       // attributes, the depth will be non-zero. We need to omit certain
740       // attributes that don't make sense.
741       switch (attr) {
742       case DW_AT_sibling:
743       case DW_AT_declaration:
744         if (curr_depth > 0) {
745           // This attribute doesn't make sense when combined with the DIE that
746           // references this DIE. We know a DIE is referencing this DIE because
747           // curr_depth is not zero
748           break;
749         }
750         LLVM_FALLTHROUGH;
751       default:
752         attributes.Append(cu, offset, attr, form);
753         break;
754       }
755 
756       if ((attr == DW_AT_specification) || (attr == DW_AT_abstract_origin)) {
757         if (form_value.ExtractValue(debug_info_data, &offset)) {
758           DWARFDIE spec_die = form_value.Reference();
759           if (spec_die)
760             spec_die.GetAttributes(attributes, curr_depth + 1);
761         }
762       } else {
763         llvm::Optional<uint8_t> fixed_skip_size = DWARFFormValue::GetFixedSize(form, cu);
764         if (fixed_skip_size)
765           offset += *fixed_skip_size;
766         else
767           DWARFFormValue::SkipValue(form, debug_info_data, &offset, cu);
768       }
769     }
770   } else {
771     attributes.Clear();
772   }
773   return attributes.Size();
774 }
775 
776 // GetAttributeValue
777 //
778 // Get the value of an attribute and return the .debug_info offset of the
779 // attribute if it was properly extracted into form_value, or zero if we fail
780 // since an offset of zero is invalid for an attribute (it would be a compile
781 // unit header).
782 dw_offset_t DWARFDebugInfoEntry::GetAttributeValue(
783     const DWARFUnit *cu, const dw_attr_t attr, DWARFFormValue &form_value,
784     dw_offset_t *end_attr_offset_ptr,
785     bool check_specification_or_abstract_origin) const {
786   SymbolFileDWARFDwo *dwo_symbol_file = cu->GetDwoSymbolFile();
787   if (dwo_symbol_file && m_tag != DW_TAG_compile_unit &&
788                          m_tag != DW_TAG_partial_unit)
789     return GetAttributeValue(dwo_symbol_file->GetCompileUnit(), attr,
790                              form_value, end_attr_offset_ptr,
791                              check_specification_or_abstract_origin);
792 
793   lldb::offset_t offset;
794   const DWARFAbbreviationDeclaration *abbrevDecl =
795       GetAbbreviationDeclarationPtr(cu, offset);
796 
797   if (abbrevDecl) {
798     uint32_t attr_idx = abbrevDecl->FindAttributeIndex(attr);
799 
800     if (attr_idx != DW_INVALID_INDEX) {
801       const DWARFDataExtractor &debug_info_data = cu->GetData();
802 
803       uint32_t idx = 0;
804       while (idx < attr_idx)
805         DWARFFormValue::SkipValue(abbrevDecl->GetFormByIndex(idx++),
806                                   debug_info_data, &offset, cu);
807 
808       const dw_offset_t attr_offset = offset;
809       form_value.SetUnit(cu);
810       form_value.SetForm(abbrevDecl->GetFormByIndex(idx));
811       if (form_value.ExtractValue(debug_info_data, &offset)) {
812         if (end_attr_offset_ptr)
813           *end_attr_offset_ptr = offset;
814         return attr_offset;
815       }
816     }
817   }
818 
819   if (check_specification_or_abstract_origin) {
820     if (GetAttributeValue(cu, DW_AT_specification, form_value)) {
821       DWARFDIE die = form_value.Reference();
822       if (die) {
823         dw_offset_t die_offset = die.GetDIE()->GetAttributeValue(
824             die.GetCU(), attr, form_value, end_attr_offset_ptr, false);
825         if (die_offset)
826           return die_offset;
827       }
828     }
829 
830     if (GetAttributeValue(cu, DW_AT_abstract_origin, form_value)) {
831       DWARFDIE die = form_value.Reference();
832       if (die) {
833         dw_offset_t die_offset = die.GetDIE()->GetAttributeValue(
834             die.GetCU(), attr, form_value, end_attr_offset_ptr, false);
835         if (die_offset)
836           return die_offset;
837       }
838     }
839   }
840 
841   if (!dwo_symbol_file)
842     return 0;
843 
844   DWARFUnit *dwo_cu = dwo_symbol_file->GetCompileUnit();
845   if (!dwo_cu)
846     return 0;
847 
848   DWARFBaseDIE dwo_cu_die = dwo_cu->GetUnitDIEOnly();
849   if (!dwo_cu_die.IsValid())
850     return 0;
851 
852   return dwo_cu_die.GetDIE()->GetAttributeValue(
853       dwo_cu, attr, form_value, end_attr_offset_ptr,
854       check_specification_or_abstract_origin);
855 }
856 
857 // GetAttributeValueAsString
858 //
859 // Get the value of an attribute as a string return it. The resulting pointer
860 // to the string data exists within the supplied SymbolFileDWARF and will only
861 // be available as long as the SymbolFileDWARF is still around and it's content
862 // doesn't change.
863 const char *DWARFDebugInfoEntry::GetAttributeValueAsString(
864     const DWARFUnit *cu, const dw_attr_t attr, const char *fail_value,
865     bool check_specification_or_abstract_origin) const {
866   DWARFFormValue form_value;
867   if (GetAttributeValue(cu, attr, form_value, nullptr,
868                         check_specification_or_abstract_origin))
869     return form_value.AsCString();
870   return fail_value;
871 }
872 
873 // GetAttributeValueAsUnsigned
874 //
875 // Get the value of an attribute as unsigned and return it.
876 uint64_t DWARFDebugInfoEntry::GetAttributeValueAsUnsigned(
877     const DWARFUnit *cu, const dw_attr_t attr, uint64_t fail_value,
878     bool check_specification_or_abstract_origin) const {
879   DWARFFormValue form_value;
880   if (GetAttributeValue(cu, attr, form_value, nullptr,
881                         check_specification_or_abstract_origin))
882     return form_value.Unsigned();
883   return fail_value;
884 }
885 
886 // GetAttributeValueAsReference
887 //
888 // Get the value of an attribute as reference and fix up and compile unit
889 // relative offsets as needed.
890 DWARFDIE DWARFDebugInfoEntry::GetAttributeValueAsReference(
891     const DWARFUnit *cu, const dw_attr_t attr,
892     bool check_specification_or_abstract_origin) const {
893   DWARFFormValue form_value;
894   if (GetAttributeValue(cu, attr, form_value, nullptr,
895                         check_specification_or_abstract_origin))
896     return form_value.Reference();
897   return {};
898 }
899 
900 uint64_t DWARFDebugInfoEntry::GetAttributeValueAsAddress(
901     const DWARFUnit *cu, const dw_attr_t attr, uint64_t fail_value,
902     bool check_specification_or_abstract_origin) const {
903   DWARFFormValue form_value;
904   if (GetAttributeValue(cu, attr, form_value, nullptr,
905                         check_specification_or_abstract_origin))
906     return form_value.Address();
907   return fail_value;
908 }
909 
910 // GetAttributeHighPC
911 //
912 // Get the hi_pc, adding hi_pc to lo_pc when specified as an <offset-from-low-
913 // pc>.
914 //
915 // Returns the hi_pc or fail_value.
916 dw_addr_t DWARFDebugInfoEntry::GetAttributeHighPC(
917     const DWARFUnit *cu, dw_addr_t lo_pc, uint64_t fail_value,
918     bool check_specification_or_abstract_origin) const {
919   DWARFFormValue form_value;
920   if (GetAttributeValue(cu, DW_AT_high_pc, form_value, nullptr,
921                         check_specification_or_abstract_origin)) {
922     dw_form_t form = form_value.Form();
923     if (form == DW_FORM_addr || form == DW_FORM_addrx ||
924         form == DW_FORM_GNU_addr_index)
925       return form_value.Address();
926 
927     // DWARF4 can specify the hi_pc as an <offset-from-lowpc>
928     return lo_pc + form_value.Unsigned();
929   }
930   return fail_value;
931 }
932 
933 // GetAttributeAddressRange
934 //
935 // Get the lo_pc and hi_pc, adding hi_pc to lo_pc when specified as an <offset-
936 // from-low-pc>.
937 //
938 // Returns true or sets lo_pc and hi_pc to fail_value.
939 bool DWARFDebugInfoEntry::GetAttributeAddressRange(
940     const DWARFUnit *cu, dw_addr_t &lo_pc, dw_addr_t &hi_pc,
941     uint64_t fail_value, bool check_specification_or_abstract_origin) const {
942   lo_pc = GetAttributeValueAsAddress(cu, DW_AT_low_pc, fail_value,
943                                      check_specification_or_abstract_origin);
944   if (lo_pc != fail_value) {
945     hi_pc = GetAttributeHighPC(cu, lo_pc, fail_value,
946                                check_specification_or_abstract_origin);
947     if (hi_pc != fail_value)
948       return true;
949   }
950   lo_pc = fail_value;
951   hi_pc = fail_value;
952   return false;
953 }
954 
955 size_t DWARFDebugInfoEntry::GetAttributeAddressRanges(
956     const DWARFUnit *cu, DWARFRangeList &ranges, bool check_hi_lo_pc,
957     bool check_specification_or_abstract_origin) const {
958   ranges.Clear();
959 
960   DWARFFormValue form_value;
961   if (GetAttributeValue(cu, DW_AT_ranges, form_value)) {
962     ranges = GetRangesOrReportError(*cu, *this, form_value);
963   } else if (check_hi_lo_pc) {
964     dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
965     dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
966     if (GetAttributeAddressRange(cu, lo_pc, hi_pc, LLDB_INVALID_ADDRESS,
967                                  check_specification_or_abstract_origin)) {
968       if (lo_pc < hi_pc)
969         ranges.Append(DWARFRangeList::Entry(lo_pc, hi_pc - lo_pc));
970     }
971   }
972   return ranges.GetSize();
973 }
974 
975 // GetName
976 //
977 // Get value of the DW_AT_name attribute and return it if one exists, else
978 // return NULL.
979 const char *DWARFDebugInfoEntry::GetName(const DWARFUnit *cu) const {
980   return GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
981 }
982 
983 // GetMangledName
984 //
985 // Get value of the DW_AT_MIPS_linkage_name attribute and return it if one
986 // exists, else return the value of the DW_AT_name attribute
987 const char *
988 DWARFDebugInfoEntry::GetMangledName(const DWARFUnit *cu,
989                                     bool substitute_name_allowed) const {
990   const char *name = nullptr;
991 
992   name = GetAttributeValueAsString(cu, DW_AT_MIPS_linkage_name, nullptr, true);
993   if (name)
994     return name;
995 
996   name = GetAttributeValueAsString(cu, DW_AT_linkage_name, nullptr, true);
997   if (name)
998     return name;
999 
1000   if (!substitute_name_allowed)
1001     return nullptr;
1002 
1003   name = GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
1004   return name;
1005 }
1006 
1007 // GetPubname
1008 //
1009 // Get value the name for a DIE as it should appear for a .debug_pubnames or
1010 // .debug_pubtypes section.
1011 const char *DWARFDebugInfoEntry::GetPubname(const DWARFUnit *cu) const {
1012   const char *name = nullptr;
1013   if (!cu)
1014     return name;
1015 
1016   name = GetAttributeValueAsString(cu, DW_AT_MIPS_linkage_name, nullptr, true);
1017   if (name)
1018     return name;
1019 
1020   name = GetAttributeValueAsString(cu, DW_AT_linkage_name, nullptr, true);
1021   if (name)
1022     return name;
1023 
1024   name = GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
1025   return name;
1026 }
1027 
1028 // BuildAddressRangeTable
1029 void DWARFDebugInfoEntry::BuildAddressRangeTable(
1030     const DWARFUnit *cu, DWARFDebugAranges *debug_aranges) const {
1031   if (m_tag) {
1032     if (m_tag == DW_TAG_subprogram) {
1033       dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
1034       dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
1035       if (GetAttributeAddressRange(cu, lo_pc, hi_pc, LLDB_INVALID_ADDRESS)) {
1036         /// printf("BuildAddressRangeTable() 0x%8.8x: %30s: [0x%8.8x -
1037         /// 0x%8.8x)\n", m_offset, DW_TAG_value_to_name(tag), lo_pc, hi_pc);
1038         debug_aranges->AppendRange(cu->GetOffset(), lo_pc, hi_pc);
1039       }
1040     }
1041 
1042     const DWARFDebugInfoEntry *child = GetFirstChild();
1043     while (child) {
1044       child->BuildAddressRangeTable(cu, debug_aranges);
1045       child = child->GetSibling();
1046     }
1047   }
1048 }
1049 
1050 // BuildFunctionAddressRangeTable
1051 //
1052 // This function is very similar to the BuildAddressRangeTable function except
1053 // that the actual DIE offset for the function is placed in the table instead
1054 // of the compile unit offset (which is the way the standard .debug_aranges
1055 // section does it).
1056 void DWARFDebugInfoEntry::BuildFunctionAddressRangeTable(
1057     const DWARFUnit *cu, DWARFDebugAranges *debug_aranges) const {
1058   if (m_tag) {
1059     if (m_tag == DW_TAG_subprogram) {
1060       dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
1061       dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
1062       if (GetAttributeAddressRange(cu, lo_pc, hi_pc, LLDB_INVALID_ADDRESS)) {
1063         //  printf("BuildAddressRangeTable() 0x%8.8x: [0x%16.16" PRIx64 " -
1064         //  0x%16.16" PRIx64 ")\n", m_offset, lo_pc, hi_pc); // DEBUG ONLY
1065         debug_aranges->AppendRange(GetOffset(), lo_pc, hi_pc);
1066       }
1067     }
1068 
1069     const DWARFDebugInfoEntry *child = GetFirstChild();
1070     while (child) {
1071       child->BuildFunctionAddressRangeTable(cu, debug_aranges);
1072       child = child->GetSibling();
1073     }
1074   }
1075 }
1076 
1077 void DWARFDebugInfoEntry::GetDWARFDeclContext(
1078     DWARFUnit *cu, DWARFDeclContext &dwarf_decl_ctx) const {
1079   const dw_tag_t tag = Tag();
1080   if (tag != DW_TAG_compile_unit && tag != DW_TAG_partial_unit) {
1081     dwarf_decl_ctx.AppendDeclContext(tag, GetName(cu));
1082     DWARFDIE parent_decl_ctx_die = GetParentDeclContextDIE(cu);
1083     if (parent_decl_ctx_die && parent_decl_ctx_die.GetDIE() != this) {
1084       if (parent_decl_ctx_die.Tag() != DW_TAG_compile_unit &&
1085           parent_decl_ctx_die.Tag() != DW_TAG_partial_unit)
1086         parent_decl_ctx_die.GetDIE()->GetDWARFDeclContext(
1087             parent_decl_ctx_die.GetCU(), dwarf_decl_ctx);
1088     }
1089   }
1090 }
1091 
1092 DWARFDIE
1093 DWARFDebugInfoEntry::GetParentDeclContextDIE(DWARFUnit *cu) const {
1094   DWARFAttributes attributes;
1095   GetAttributes(cu, attributes);
1096   return GetParentDeclContextDIE(cu, attributes);
1097 }
1098 
1099 DWARFDIE
1100 DWARFDebugInfoEntry::GetParentDeclContextDIE(
1101     DWARFUnit *cu, const DWARFAttributes &attributes) const {
1102   DWARFDIE die(cu, const_cast<DWARFDebugInfoEntry *>(this));
1103 
1104   while (die) {
1105     // If this is the original DIE that we are searching for a declaration for,
1106     // then don't look in the cache as we don't want our own decl context to be
1107     // our decl context...
1108     if (die.GetDIE() != this) {
1109       switch (die.Tag()) {
1110       case DW_TAG_compile_unit:
1111       case DW_TAG_partial_unit:
1112       case DW_TAG_namespace:
1113       case DW_TAG_structure_type:
1114       case DW_TAG_union_type:
1115       case DW_TAG_class_type:
1116         return die;
1117 
1118       default:
1119         break;
1120       }
1121     }
1122 
1123     DWARFDIE spec_die = attributes.FormValueAsReference(DW_AT_specification);
1124     if (spec_die) {
1125       DWARFDIE decl_ctx_die = spec_die.GetParentDeclContextDIE();
1126       if (decl_ctx_die)
1127         return decl_ctx_die;
1128     }
1129 
1130     DWARFDIE abs_die = attributes.FormValueAsReference(DW_AT_abstract_origin);
1131     if (abs_die) {
1132       DWARFDIE decl_ctx_die = abs_die.GetParentDeclContextDIE();
1133       if (decl_ctx_die)
1134         return decl_ctx_die;
1135     }
1136 
1137     die = die.GetParent();
1138   }
1139   return DWARFDIE();
1140 }
1141 
1142 const char *DWARFDebugInfoEntry::GetQualifiedName(DWARFUnit *cu,
1143                                                   std::string &storage) const {
1144   DWARFAttributes attributes;
1145   GetAttributes(cu, attributes);
1146   return GetQualifiedName(cu, attributes, storage);
1147 }
1148 
1149 const char *
1150 DWARFDebugInfoEntry::GetQualifiedName(DWARFUnit *cu,
1151                                       const DWARFAttributes &attributes,
1152                                       std::string &storage) const {
1153 
1154   const char *name = GetName(cu);
1155 
1156   if (name) {
1157     DWARFDIE parent_decl_ctx_die = GetParentDeclContextDIE(cu);
1158     storage.clear();
1159     // TODO: change this to get the correct decl context parent....
1160     while (parent_decl_ctx_die) {
1161       const dw_tag_t parent_tag = parent_decl_ctx_die.Tag();
1162       switch (parent_tag) {
1163       case DW_TAG_namespace: {
1164         const char *namespace_name = parent_decl_ctx_die.GetName();
1165         if (namespace_name) {
1166           storage.insert(0, "::");
1167           storage.insert(0, namespace_name);
1168         } else {
1169           storage.insert(0, "(anonymous namespace)::");
1170         }
1171         parent_decl_ctx_die = parent_decl_ctx_die.GetParentDeclContextDIE();
1172       } break;
1173 
1174       case DW_TAG_class_type:
1175       case DW_TAG_structure_type:
1176       case DW_TAG_union_type: {
1177         const char *class_union_struct_name = parent_decl_ctx_die.GetName();
1178 
1179         if (class_union_struct_name) {
1180           storage.insert(0, "::");
1181           storage.insert(0, class_union_struct_name);
1182         }
1183         parent_decl_ctx_die = parent_decl_ctx_die.GetParentDeclContextDIE();
1184       } break;
1185 
1186       default:
1187         parent_decl_ctx_die.Clear();
1188         break;
1189       }
1190     }
1191 
1192     if (storage.empty())
1193       storage.append("::");
1194 
1195     storage.append(name);
1196   }
1197   if (storage.empty())
1198     return nullptr;
1199   return storage.c_str();
1200 }
1201 
1202 bool DWARFDebugInfoEntry::LookupAddress(const dw_addr_t address,
1203                                         const DWARFUnit *cu,
1204                                         DWARFDebugInfoEntry **function_die,
1205                                         DWARFDebugInfoEntry **block_die) {
1206   bool found_address = false;
1207   if (m_tag) {
1208     bool check_children = false;
1209     bool match_addr_range = false;
1210     //  printf("0x%8.8x: %30s: address = 0x%8.8x - ", m_offset,
1211     //  DW_TAG_value_to_name(tag), address);
1212     switch (m_tag) {
1213     case DW_TAG_array_type:
1214       break;
1215     case DW_TAG_class_type:
1216       check_children = true;
1217       break;
1218     case DW_TAG_entry_point:
1219     case DW_TAG_enumeration_type:
1220     case DW_TAG_formal_parameter:
1221     case DW_TAG_imported_declaration:
1222     case DW_TAG_label:
1223       break;
1224     case DW_TAG_lexical_block:
1225       check_children = true;
1226       match_addr_range = true;
1227       break;
1228     case DW_TAG_member:
1229     case DW_TAG_pointer_type:
1230     case DW_TAG_reference_type:
1231       break;
1232     case DW_TAG_compile_unit:
1233       match_addr_range = true;
1234       break;
1235     case DW_TAG_string_type:
1236       break;
1237     case DW_TAG_structure_type:
1238       check_children = true;
1239       break;
1240     case DW_TAG_subroutine_type:
1241     case DW_TAG_typedef:
1242     case DW_TAG_union_type:
1243     case DW_TAG_unspecified_parameters:
1244     case DW_TAG_variant:
1245       break;
1246     case DW_TAG_common_block:
1247       check_children = true;
1248       break;
1249     case DW_TAG_common_inclusion:
1250     case DW_TAG_inheritance:
1251       break;
1252     case DW_TAG_inlined_subroutine:
1253       check_children = true;
1254       match_addr_range = true;
1255       break;
1256     case DW_TAG_module:
1257       match_addr_range = true;
1258       break;
1259     case DW_TAG_ptr_to_member_type:
1260     case DW_TAG_set_type:
1261     case DW_TAG_subrange_type:
1262     case DW_TAG_with_stmt:
1263     case DW_TAG_access_declaration:
1264     case DW_TAG_base_type:
1265       break;
1266     case DW_TAG_catch_block:
1267       match_addr_range = true;
1268       break;
1269     case DW_TAG_const_type:
1270     case DW_TAG_constant:
1271     case DW_TAG_enumerator:
1272     case DW_TAG_file_type:
1273     case DW_TAG_friend:
1274     case DW_TAG_namelist:
1275     case DW_TAG_namelist_item:
1276     case DW_TAG_packed_type:
1277       break;
1278     case DW_TAG_subprogram:
1279       match_addr_range = true;
1280       break;
1281     case DW_TAG_template_type_parameter:
1282     case DW_TAG_template_value_parameter:
1283     case DW_TAG_GNU_template_parameter_pack:
1284     case DW_TAG_thrown_type:
1285       break;
1286     case DW_TAG_try_block:
1287       match_addr_range = true;
1288       break;
1289     case DW_TAG_variant_part:
1290     case DW_TAG_variable:
1291     case DW_TAG_volatile_type:
1292     case DW_TAG_dwarf_procedure:
1293     case DW_TAG_restrict_type:
1294     case DW_TAG_interface_type:
1295       break;
1296     case DW_TAG_namespace:
1297       check_children = true;
1298       break;
1299     case DW_TAG_imported_module:
1300     case DW_TAG_unspecified_type:
1301       break;
1302     case DW_TAG_partial_unit:
1303       match_addr_range = true;
1304       break;
1305     case DW_TAG_imported_unit:
1306     case DW_TAG_shared_type:
1307     default:
1308       break;
1309     }
1310 
1311     if (match_addr_range) {
1312       dw_addr_t lo_pc =
1313           GetAttributeValueAsAddress(cu, DW_AT_low_pc, LLDB_INVALID_ADDRESS);
1314       if (lo_pc != LLDB_INVALID_ADDRESS) {
1315         dw_addr_t hi_pc = GetAttributeHighPC(cu, lo_pc, LLDB_INVALID_ADDRESS);
1316         if (hi_pc != LLDB_INVALID_ADDRESS) {
1317           //  printf("\n0x%8.8x: %30s: address = 0x%8.8x  [0x%8.8x - 0x%8.8x) ",
1318           //  m_offset, DW_TAG_value_to_name(tag), address, lo_pc, hi_pc);
1319           if ((lo_pc <= address) && (address < hi_pc)) {
1320             found_address = true;
1321             //  puts("***MATCH***");
1322             switch (m_tag) {
1323             case DW_TAG_compile_unit: // File
1324             case DW_TAG_partial_unit: // File
1325               check_children =
1326                   ((function_die != nullptr) || (block_die != nullptr));
1327               break;
1328 
1329             case DW_TAG_subprogram: // Function
1330               if (function_die)
1331                 *function_die = this;
1332               check_children = (block_die != nullptr);
1333               break;
1334 
1335             case DW_TAG_inlined_subroutine: // Inlined Function
1336             case DW_TAG_lexical_block:      // Block { } in code
1337               if (block_die) {
1338                 *block_die = this;
1339                 check_children = true;
1340               }
1341               break;
1342 
1343             default:
1344               check_children = true;
1345               break;
1346             }
1347           }
1348         } else {
1349           // Compile units may not have a valid high/low pc when there
1350           // are address gaps in subroutines so we must always search
1351           // if there is no valid high and low PC.
1352           check_children =
1353               (m_tag == DW_TAG_compile_unit || m_tag == DW_TAG_partial_unit) &&
1354               ((function_die != nullptr) || (block_die != nullptr));
1355         }
1356       } else {
1357         DWARFRangeList ranges;
1358         if (GetAttributeAddressRanges(cu, ranges, /*check_hi_lo_pc*/ false) &&
1359             ranges.FindEntryThatContains(address)) {
1360           found_address = true;
1361           //  puts("***MATCH***");
1362           switch (m_tag) {
1363           case DW_TAG_compile_unit: // File
1364           case DW_TAG_partial_unit: // File
1365               check_children =
1366                   ((function_die != nullptr) || (block_die != nullptr));
1367               break;
1368 
1369           case DW_TAG_subprogram: // Function
1370             if (function_die)
1371               *function_die = this;
1372             check_children = (block_die != nullptr);
1373             break;
1374 
1375           case DW_TAG_inlined_subroutine: // Inlined Function
1376           case DW_TAG_lexical_block:      // Block { } in code
1377             if (block_die) {
1378               *block_die = this;
1379               check_children = true;
1380             }
1381             break;
1382 
1383           default:
1384             check_children = true;
1385             break;
1386           }
1387         } else {
1388           check_children = false;
1389         }
1390       }
1391     }
1392 
1393     if (check_children) {
1394       //  printf("checking children\n");
1395       DWARFDebugInfoEntry *child = GetFirstChild();
1396       while (child) {
1397         if (child->LookupAddress(address, cu, function_die, block_die))
1398           return true;
1399         child = child->GetSibling();
1400       }
1401     }
1402   }
1403   return found_address;
1404 }
1405 
1406 const DWARFAbbreviationDeclaration *
1407 DWARFDebugInfoEntry::GetAbbreviationDeclarationPtr(
1408     const DWARFUnit *cu, lldb::offset_t &offset) const {
1409   if (cu) {
1410     offset = GetOffset();
1411 
1412     const DWARFAbbreviationDeclarationSet *abbrev_set = cu->GetAbbreviations();
1413     if (abbrev_set) {
1414       const DWARFAbbreviationDeclaration *abbrev_decl =
1415           abbrev_set->GetAbbreviationDeclaration(m_abbr_idx);
1416       if (abbrev_decl) {
1417         // Make sure the abbreviation code still matches. If it doesn't and the
1418         // DWARF data was mmap'ed, the backing file might have been modified
1419         // which is bad news.
1420         const uint64_t abbrev_code = cu->GetData().GetULEB128(&offset);
1421 
1422         if (abbrev_decl->Code() == abbrev_code)
1423           return abbrev_decl;
1424 
1425         SymbolFileDWARF *dwarf2Data = cu->GetSymbolFileDWARF();
1426 
1427         dwarf2Data->GetObjectFile()->GetModule()->ReportErrorIfModifyDetected(
1428             "0x%8.8x: the DWARF debug information has been modified (abbrev "
1429             "code was %u, and is now %u)",
1430             GetOffset(), (uint32_t)abbrev_decl->Code(), (uint32_t)abbrev_code);
1431       }
1432     }
1433   }
1434   offset = DW_INVALID_OFFSET;
1435   return nullptr;
1436 }
1437 
1438 bool DWARFDebugInfoEntry::operator==(const DWARFDebugInfoEntry &rhs) const {
1439   return m_offset == rhs.m_offset && m_parent_idx == rhs.m_parent_idx &&
1440          m_sibling_idx == rhs.m_sibling_idx &&
1441          m_abbr_idx == rhs.m_abbr_idx && m_has_children == rhs.m_has_children &&
1442          m_tag == rhs.m_tag;
1443 }
1444 
1445 bool DWARFDebugInfoEntry::operator!=(const DWARFDebugInfoEntry &rhs) const {
1446   return !(*this == rhs);
1447 }
1448