1 //===-- DWARFDebugInfoEntry.cpp -------------------------------------------===//
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 <cassert>
12 
13 #include <algorithm>
14 
15 #include "llvm/Support/LEB128.h"
16 
17 #include "lldb/Core/Module.h"
18 #include "lldb/Expression/DWARFExpression.h"
19 #include "lldb/Symbol/ObjectFile.h"
20 #include "lldb/Utility/Stream.h"
21 
22 #include "DWARFCompileUnit.h"
23 #include "DWARFDebugAbbrev.h"
24 #include "DWARFDebugAranges.h"
25 #include "DWARFDebugInfo.h"
26 #include "DWARFDebugRanges.h"
27 #include "DWARFDeclContext.h"
28 #include "DWARFFormValue.h"
29 #include "DWARFUnit.h"
30 #include "SymbolFileDWARF.h"
31 #include "SymbolFileDWARFDwo.h"
32 
33 using namespace lldb_private;
34 using namespace std;
35 extern int g_verbose;
36 
37 // Extract a debug info entry for a given DWARFUnit from the data
38 // starting at the offset in offset_ptr
39 bool DWARFDebugInfoEntry::Extract(const DWARFDataExtractor &data,
40                                   const DWARFUnit *cu,
41                                   lldb::offset_t *offset_ptr) {
42   m_offset = *offset_ptr;
43   m_parent_idx = 0;
44   m_sibling_idx = 0;
45   const uint64_t abbr_idx = data.GetULEB128(offset_ptr);
46   lldbassert(abbr_idx <= UINT16_MAX);
47   m_abbr_idx = abbr_idx;
48 
49   // assert (fixed_form_sizes);  // For best performance this should be
50   // specified!
51 
52   if (m_abbr_idx == 0) {
53     m_tag = llvm::dwarf::DW_TAG_null;
54     m_has_children = false;
55     return true; // NULL debug tag entry
56   }
57 
58   lldb::offset_t offset = *offset_ptr;
59   const auto *abbrevDecl = GetAbbreviationDeclarationPtr(cu);
60   if (abbrevDecl == nullptr) {
61     cu->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
62         "{0x%8.8x}: invalid abbreviation code %u, please file a bug and "
63         "attach the file at the start of this error message",
64         m_offset, (unsigned)abbr_idx);
65     // WE can't parse anymore if the DWARF is borked...
66     *offset_ptr = UINT32_MAX;
67     return false;
68   }
69   m_tag = abbrevDecl->Tag();
70   m_has_children = abbrevDecl->HasChildren();
71   // Skip all data in the .debug_info or .debug_types for the attributes
72   const uint32_t numAttributes = abbrevDecl->NumAttributes();
73   uint32_t i;
74   dw_form_t form;
75   for (i = 0; i < numAttributes; ++i) {
76     form = abbrevDecl->GetFormByIndexUnchecked(i);
77     llvm::Optional<uint8_t> fixed_skip_size =
78         DWARFFormValue::GetFixedSize(form, cu);
79     if (fixed_skip_size)
80       offset += *fixed_skip_size;
81     else {
82       bool form_is_indirect = false;
83       do {
84         form_is_indirect = false;
85         uint32_t form_size = 0;
86         switch (form) {
87         // Blocks if inlined data that have a length field and the data bytes
88         // inlined in the .debug_info/.debug_types
89         case DW_FORM_exprloc:
90         case DW_FORM_block:
91           form_size = data.GetULEB128(&offset);
92           break;
93         case DW_FORM_block1:
94           form_size = data.GetU8_unchecked(&offset);
95           break;
96         case DW_FORM_block2:
97           form_size = data.GetU16_unchecked(&offset);
98           break;
99         case DW_FORM_block4:
100           form_size = data.GetU32_unchecked(&offset);
101           break;
102 
103         // Inlined NULL terminated C-strings
104         case DW_FORM_string:
105           data.GetCStr(&offset);
106           break;
107 
108         // Compile unit address sized values
109         case DW_FORM_addr:
110           form_size = cu->GetAddressByteSize();
111           break;
112         case DW_FORM_ref_addr:
113           if (cu->GetVersion() <= 2)
114             form_size = cu->GetAddressByteSize();
115           else
116             form_size = 4;
117           break;
118 
119         // 0 sized form
120         case DW_FORM_flag_present:
121           form_size = 0;
122           break;
123 
124         // 1 byte values
125         case DW_FORM_addrx1:
126         case DW_FORM_data1:
127         case DW_FORM_flag:
128         case DW_FORM_ref1:
129         case DW_FORM_strx1:
130           form_size = 1;
131           break;
132 
133         // 2 byte values
134         case DW_FORM_addrx2:
135         case DW_FORM_data2:
136         case DW_FORM_ref2:
137         case DW_FORM_strx2:
138           form_size = 2;
139           break;
140 
141         // 3 byte values
142         case DW_FORM_addrx3:
143         case DW_FORM_strx3:
144           form_size = 3;
145           break;
146 
147         // 4 byte values
148         case DW_FORM_addrx4:
149         case DW_FORM_data4:
150         case DW_FORM_ref4:
151         case DW_FORM_strx4:
152           form_size = 4;
153           break;
154 
155         // 8 byte values
156         case DW_FORM_data8:
157         case DW_FORM_ref8:
158         case DW_FORM_ref_sig8:
159           form_size = 8;
160           break;
161 
162         // signed or unsigned LEB 128 values
163         case DW_FORM_addrx:
164         case DW_FORM_loclistx:
165         case DW_FORM_rnglistx:
166         case DW_FORM_sdata:
167         case DW_FORM_udata:
168         case DW_FORM_ref_udata:
169         case DW_FORM_GNU_addr_index:
170         case DW_FORM_GNU_str_index:
171         case DW_FORM_strx:
172           data.Skip_LEB128(&offset);
173           break;
174 
175         case DW_FORM_indirect:
176           form_is_indirect = true;
177           form = data.GetULEB128(&offset);
178           break;
179 
180         case DW_FORM_strp:
181         case DW_FORM_line_strp:
182         case DW_FORM_sec_offset:
183           data.GetU32(&offset);
184           break;
185 
186         case DW_FORM_implicit_const:
187           form_size = 0;
188           break;
189 
190         default:
191           cu->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
192               "{0x%8.8x}: Unsupported DW_FORM_0x%x, please file a bug and "
193               "attach the file at the start of this error message",
194               m_offset, (unsigned)form);
195           *offset_ptr = m_offset;
196           return false;
197         }
198         offset += form_size;
199 
200       } while (form_is_indirect);
201     }
202   }
203   *offset_ptr = offset;
204   return true;
205 }
206 
207 static DWARFRangeList GetRangesOrReportError(DWARFUnit &unit,
208                                              const DWARFDebugInfoEntry &die,
209                                              const DWARFFormValue &value) {
210   llvm::Expected<DWARFRangeList> expected_ranges =
211       (value.Form() == DW_FORM_rnglistx)
212           ? unit.FindRnglistFromIndex(value.Unsigned())
213           : unit.FindRnglistFromOffset(value.Unsigned());
214   if (expected_ranges)
215     return std::move(*expected_ranges);
216   unit.GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
217       "{0x%8.8x}: DIE has DW_AT_ranges(%s 0x%" PRIx64 ") attribute, but "
218       "range extraction failed (%s), please file a bug "
219       "and attach the file at the start of this error message",
220       die.GetOffset(),
221       llvm::dwarf::FormEncodingString(value.Form()).str().c_str(),
222       value.Unsigned(), toString(expected_ranges.takeError()).c_str());
223   return DWARFRangeList();
224 }
225 
226 // GetDIENamesAndRanges
227 //
228 // Gets the valid address ranges for a given DIE by looking for a
229 // DW_AT_low_pc/DW_AT_high_pc pair, DW_AT_entry_pc, or DW_AT_ranges attributes.
230 bool DWARFDebugInfoEntry::GetDIENamesAndRanges(
231     DWARFUnit *cu, const char *&name, const char *&mangled,
232     DWARFRangeList &ranges, int &decl_file, int &decl_line, int &decl_column,
233     int &call_file, int &call_line, int &call_column,
234     DWARFExpression *frame_base) const {
235   dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
236   dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
237   std::vector<DWARFDIE> dies;
238   bool set_frame_base_loclist_addr = false;
239 
240   const auto *abbrevDecl = GetAbbreviationDeclarationPtr(cu);
241 
242   SymbolFileDWARF &dwarf = cu->GetSymbolFileDWARF();
243   lldb::ModuleSP module = dwarf.GetObjectFile()->GetModule();
244 
245   if (abbrevDecl) {
246     const DWARFDataExtractor &data = cu->GetData();
247     lldb::offset_t offset = GetFirstAttributeOffset();
248 
249     if (!data.ValidOffset(offset))
250       return false;
251 
252     const uint32_t numAttributes = abbrevDecl->NumAttributes();
253     bool do_offset = false;
254 
255     for (uint32_t i = 0; i < numAttributes; ++i) {
256       DWARFFormValue form_value(cu);
257       dw_attr_t attr;
258       abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
259 
260       if (form_value.ExtractValue(data, &offset)) {
261         switch (attr) {
262         case DW_AT_low_pc:
263           lo_pc = form_value.Address();
264 
265           if (do_offset)
266             hi_pc += lo_pc;
267           do_offset = false;
268           break;
269 
270         case DW_AT_entry_pc:
271           lo_pc = form_value.Address();
272           break;
273 
274         case DW_AT_high_pc:
275           if (form_value.Form() == DW_FORM_addr ||
276               form_value.Form() == DW_FORM_addrx ||
277               form_value.Form() == DW_FORM_GNU_addr_index) {
278             hi_pc = form_value.Address();
279           } else {
280             hi_pc = form_value.Unsigned();
281             if (lo_pc == LLDB_INVALID_ADDRESS)
282               do_offset = hi_pc != LLDB_INVALID_ADDRESS;
283             else
284               hi_pc += lo_pc; // DWARF 4 introduces <offset-from-lo-pc> to save
285                               // on relocations
286           }
287           break;
288 
289         case DW_AT_ranges:
290           ranges = GetRangesOrReportError(*cu, *this, form_value);
291           break;
292 
293         case DW_AT_name:
294           if (name == nullptr)
295             name = form_value.AsCString();
296           break;
297 
298         case DW_AT_MIPS_linkage_name:
299         case DW_AT_linkage_name:
300           if (mangled == nullptr)
301             mangled = form_value.AsCString();
302           break;
303 
304         case DW_AT_abstract_origin:
305           dies.push_back(form_value.Reference());
306           break;
307 
308         case DW_AT_specification:
309           dies.push_back(form_value.Reference());
310           break;
311 
312         case DW_AT_decl_file:
313           if (decl_file == 0)
314             decl_file = form_value.Unsigned();
315           break;
316 
317         case DW_AT_decl_line:
318           if (decl_line == 0)
319             decl_line = form_value.Unsigned();
320           break;
321 
322         case DW_AT_decl_column:
323           if (decl_column == 0)
324             decl_column = form_value.Unsigned();
325           break;
326 
327         case DW_AT_call_file:
328           if (call_file == 0)
329             call_file = form_value.Unsigned();
330           break;
331 
332         case DW_AT_call_line:
333           if (call_line == 0)
334             call_line = form_value.Unsigned();
335           break;
336 
337         case DW_AT_call_column:
338           if (call_column == 0)
339             call_column = form_value.Unsigned();
340           break;
341 
342         case DW_AT_frame_base:
343           if (frame_base) {
344             if (form_value.BlockData()) {
345               uint32_t block_offset =
346                   form_value.BlockData() - data.GetDataStart();
347               uint32_t block_length = form_value.Unsigned();
348               *frame_base = DWARFExpression(
349                   module, DataExtractor(data, block_offset, block_length), cu);
350             } else {
351               DataExtractor data = cu->GetLocationData();
352               const dw_offset_t offset = form_value.Unsigned();
353               if (data.ValidOffset(offset)) {
354                 data = DataExtractor(data, offset, data.GetByteSize() - offset);
355                 *frame_base = DWARFExpression(module, data, cu);
356                 if (lo_pc != LLDB_INVALID_ADDRESS) {
357                   assert(lo_pc >= cu->GetBaseAddress());
358                   frame_base->SetLocationListAddresses(cu->GetBaseAddress(),
359                                                        lo_pc);
360                 } else {
361                   set_frame_base_loclist_addr = true;
362                 }
363               }
364             }
365           }
366           break;
367 
368         default:
369           break;
370         }
371       }
372     }
373   }
374 
375   if (ranges.IsEmpty()) {
376     if (lo_pc != LLDB_INVALID_ADDRESS) {
377       if (hi_pc != LLDB_INVALID_ADDRESS && hi_pc > lo_pc)
378         ranges.Append(DWARFRangeList::Entry(lo_pc, hi_pc - lo_pc));
379       else
380         ranges.Append(DWARFRangeList::Entry(lo_pc, 0));
381     }
382   }
383 
384   if (set_frame_base_loclist_addr) {
385     dw_addr_t lowest_range_pc = ranges.GetMinRangeBase(0);
386     assert(lowest_range_pc >= cu->GetBaseAddress());
387     frame_base->SetLocationListAddresses(cu->GetBaseAddress(), lowest_range_pc);
388   }
389 
390   if (ranges.IsEmpty() || name == nullptr || mangled == nullptr) {
391     for (const DWARFDIE &die : dies) {
392       if (die) {
393         die.GetDIE()->GetDIENamesAndRanges(die.GetCU(), name, mangled, ranges,
394                                            decl_file, decl_line, decl_column,
395                                            call_file, call_line, call_column);
396       }
397     }
398   }
399   return !ranges.IsEmpty();
400 }
401 
402 // Get all attribute values for a given DIE, including following any
403 // specification or abstract origin attributes and including those in the
404 // results. Any duplicate attributes will have the first instance take
405 // precedence (this can happen for declaration attributes).
406 size_t DWARFDebugInfoEntry::GetAttributes(DWARFUnit *cu,
407                                           DWARFAttributes &attributes,
408                                           Recurse recurse,
409                                           uint32_t curr_depth) const {
410   const auto *abbrevDecl = GetAbbreviationDeclarationPtr(cu);
411   if (abbrevDecl) {
412     const DWARFDataExtractor &data = cu->GetData();
413     lldb::offset_t offset = GetFirstAttributeOffset();
414 
415     const uint32_t num_attributes = abbrevDecl->NumAttributes();
416     for (uint32_t i = 0; i < num_attributes; ++i) {
417       DWARFFormValue form_value(cu);
418       dw_attr_t attr;
419       abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
420       const dw_form_t form = form_value.Form();
421 
422       // If we are tracking down DW_AT_specification or DW_AT_abstract_origin
423       // attributes, the depth will be non-zero. We need to omit certain
424       // attributes that don't make sense.
425       switch (attr) {
426       case DW_AT_sibling:
427       case DW_AT_declaration:
428         if (curr_depth > 0) {
429           // This attribute doesn't make sense when combined with the DIE that
430           // references this DIE. We know a DIE is referencing this DIE because
431           // curr_depth is not zero
432           break;
433         }
434         LLVM_FALLTHROUGH;
435       default:
436         attributes.Append(form_value, offset, attr);
437         break;
438       }
439 
440       if (recurse == Recurse::yes &&
441           ((attr == DW_AT_specification) || (attr == DW_AT_abstract_origin))) {
442         if (form_value.ExtractValue(data, &offset)) {
443           DWARFDIE spec_die = form_value.Reference();
444           if (spec_die)
445             spec_die.GetDIE()->GetAttributes(spec_die.GetCU(), attributes,
446                                              recurse, curr_depth + 1);
447         }
448       } else {
449         llvm::Optional<uint8_t> fixed_skip_size = DWARFFormValue::GetFixedSize(form, cu);
450         if (fixed_skip_size)
451           offset += *fixed_skip_size;
452         else
453           DWARFFormValue::SkipValue(form, data, &offset, cu);
454       }
455     }
456   } else {
457     attributes.Clear();
458   }
459   return attributes.Size();
460 }
461 
462 // GetAttributeValue
463 //
464 // Get the value of an attribute and return the .debug_info or .debug_types
465 // offset of the attribute if it was properly extracted into form_value,
466 // or zero if we fail since an offset of zero is invalid for an attribute (it
467 // would be a compile unit header).
468 dw_offset_t DWARFDebugInfoEntry::GetAttributeValue(
469     const DWARFUnit *cu, const dw_attr_t attr, DWARFFormValue &form_value,
470     dw_offset_t *end_attr_offset_ptr,
471     bool check_specification_or_abstract_origin) const {
472   if (const auto *abbrevDecl = GetAbbreviationDeclarationPtr(cu)) {
473     uint32_t attr_idx = abbrevDecl->FindAttributeIndex(attr);
474 
475     if (attr_idx != DW_INVALID_INDEX) {
476       const DWARFDataExtractor &data = cu->GetData();
477       lldb::offset_t offset = GetFirstAttributeOffset();
478 
479       uint32_t idx = 0;
480       while (idx < attr_idx)
481         DWARFFormValue::SkipValue(abbrevDecl->GetFormByIndex(idx++),
482                                   data, &offset, cu);
483 
484       const dw_offset_t attr_offset = offset;
485       form_value.SetUnit(cu);
486       form_value.SetForm(abbrevDecl->GetFormByIndex(idx));
487       if (form_value.ExtractValue(data, &offset)) {
488         if (end_attr_offset_ptr)
489           *end_attr_offset_ptr = offset;
490         return attr_offset;
491       }
492     }
493   }
494 
495   if (check_specification_or_abstract_origin) {
496     if (GetAttributeValue(cu, DW_AT_specification, form_value)) {
497       DWARFDIE die = form_value.Reference();
498       if (die) {
499         dw_offset_t die_offset = die.GetDIE()->GetAttributeValue(
500             die.GetCU(), attr, form_value, end_attr_offset_ptr, false);
501         if (die_offset)
502           return die_offset;
503       }
504     }
505 
506     if (GetAttributeValue(cu, DW_AT_abstract_origin, form_value)) {
507       DWARFDIE die = form_value.Reference();
508       if (die) {
509         dw_offset_t die_offset = die.GetDIE()->GetAttributeValue(
510             die.GetCU(), attr, form_value, end_attr_offset_ptr, false);
511         if (die_offset)
512           return die_offset;
513       }
514     }
515   }
516   return 0;
517 }
518 
519 // GetAttributeValueAsString
520 //
521 // Get the value of an attribute as a string return it. The resulting pointer
522 // to the string data exists within the supplied SymbolFileDWARF and will only
523 // be available as long as the SymbolFileDWARF is still around and it's content
524 // doesn't change.
525 const char *DWARFDebugInfoEntry::GetAttributeValueAsString(
526     const DWARFUnit *cu, const dw_attr_t attr, const char *fail_value,
527     bool check_specification_or_abstract_origin) const {
528   DWARFFormValue form_value;
529   if (GetAttributeValue(cu, attr, form_value, nullptr,
530                         check_specification_or_abstract_origin))
531     return form_value.AsCString();
532   return fail_value;
533 }
534 
535 // GetAttributeValueAsUnsigned
536 //
537 // Get the value of an attribute as unsigned and return it.
538 uint64_t DWARFDebugInfoEntry::GetAttributeValueAsUnsigned(
539     const DWARFUnit *cu, const dw_attr_t attr, uint64_t fail_value,
540     bool check_specification_or_abstract_origin) const {
541   DWARFFormValue form_value;
542   if (GetAttributeValue(cu, attr, form_value, nullptr,
543                         check_specification_or_abstract_origin))
544     return form_value.Unsigned();
545   return fail_value;
546 }
547 
548 // GetAttributeValueAsReference
549 //
550 // Get the value of an attribute as reference and fix up and compile unit
551 // relative offsets as needed.
552 DWARFDIE DWARFDebugInfoEntry::GetAttributeValueAsReference(
553     const DWARFUnit *cu, const dw_attr_t attr,
554     bool check_specification_or_abstract_origin) const {
555   DWARFFormValue form_value;
556   if (GetAttributeValue(cu, attr, form_value, nullptr,
557                         check_specification_or_abstract_origin))
558     return form_value.Reference();
559   return {};
560 }
561 
562 uint64_t DWARFDebugInfoEntry::GetAttributeValueAsAddress(
563     const DWARFUnit *cu, const dw_attr_t attr, uint64_t fail_value,
564     bool check_specification_or_abstract_origin) const {
565   DWARFFormValue form_value;
566   if (GetAttributeValue(cu, attr, form_value, nullptr,
567                         check_specification_or_abstract_origin))
568     return form_value.Address();
569   return fail_value;
570 }
571 
572 // GetAttributeHighPC
573 //
574 // Get the hi_pc, adding hi_pc to lo_pc when specified as an <offset-from-low-
575 // pc>.
576 //
577 // Returns the hi_pc or fail_value.
578 dw_addr_t DWARFDebugInfoEntry::GetAttributeHighPC(
579     const DWARFUnit *cu, dw_addr_t lo_pc, uint64_t fail_value,
580     bool check_specification_or_abstract_origin) const {
581   DWARFFormValue form_value;
582   if (GetAttributeValue(cu, DW_AT_high_pc, form_value, nullptr,
583                         check_specification_or_abstract_origin)) {
584     dw_form_t form = form_value.Form();
585     if (form == DW_FORM_addr || form == DW_FORM_addrx ||
586         form == DW_FORM_GNU_addr_index)
587       return form_value.Address();
588 
589     // DWARF4 can specify the hi_pc as an <offset-from-lowpc>
590     return lo_pc + form_value.Unsigned();
591   }
592   return fail_value;
593 }
594 
595 // GetAttributeAddressRange
596 //
597 // Get the lo_pc and hi_pc, adding hi_pc to lo_pc when specified as an <offset-
598 // from-low-pc>.
599 //
600 // Returns true or sets lo_pc and hi_pc to fail_value.
601 bool DWARFDebugInfoEntry::GetAttributeAddressRange(
602     const DWARFUnit *cu, dw_addr_t &lo_pc, dw_addr_t &hi_pc,
603     uint64_t fail_value, bool check_specification_or_abstract_origin) const {
604   lo_pc = GetAttributeValueAsAddress(cu, DW_AT_low_pc, fail_value,
605                                      check_specification_or_abstract_origin);
606   if (lo_pc != fail_value) {
607     hi_pc = GetAttributeHighPC(cu, lo_pc, fail_value,
608                                check_specification_or_abstract_origin);
609     if (hi_pc != fail_value)
610       return true;
611   }
612   lo_pc = fail_value;
613   hi_pc = fail_value;
614   return false;
615 }
616 
617 size_t DWARFDebugInfoEntry::GetAttributeAddressRanges(
618     DWARFUnit *cu, DWARFRangeList &ranges, bool check_hi_lo_pc,
619     bool check_specification_or_abstract_origin) const {
620   ranges.Clear();
621 
622   DWARFFormValue form_value;
623   if (GetAttributeValue(cu, DW_AT_ranges, form_value)) {
624     ranges = GetRangesOrReportError(*cu, *this, form_value);
625   } else if (check_hi_lo_pc) {
626     dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
627     dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
628     if (GetAttributeAddressRange(cu, lo_pc, hi_pc, LLDB_INVALID_ADDRESS,
629                                  check_specification_or_abstract_origin)) {
630       if (lo_pc < hi_pc)
631         ranges.Append(DWARFRangeList::Entry(lo_pc, hi_pc - lo_pc));
632     }
633   }
634   return ranges.GetSize();
635 }
636 
637 // GetName
638 //
639 // Get value of the DW_AT_name attribute and return it if one exists, else
640 // return NULL.
641 const char *DWARFDebugInfoEntry::GetName(const DWARFUnit *cu) const {
642   return GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
643 }
644 
645 // GetMangledName
646 //
647 // Get value of the DW_AT_MIPS_linkage_name attribute and return it if one
648 // exists, else return the value of the DW_AT_name attribute
649 const char *
650 DWARFDebugInfoEntry::GetMangledName(const DWARFUnit *cu,
651                                     bool substitute_name_allowed) const {
652   const char *name = nullptr;
653 
654   name = GetAttributeValueAsString(cu, DW_AT_MIPS_linkage_name, nullptr, true);
655   if (name)
656     return name;
657 
658   name = GetAttributeValueAsString(cu, DW_AT_linkage_name, nullptr, true);
659   if (name)
660     return name;
661 
662   if (!substitute_name_allowed)
663     return nullptr;
664 
665   name = GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
666   return name;
667 }
668 
669 // GetPubname
670 //
671 // Get value the name for a DIE as it should appear for a .debug_pubnames or
672 // .debug_pubtypes section.
673 const char *DWARFDebugInfoEntry::GetPubname(const DWARFUnit *cu) const {
674   const char *name = nullptr;
675   if (!cu)
676     return name;
677 
678   name = GetAttributeValueAsString(cu, DW_AT_MIPS_linkage_name, nullptr, true);
679   if (name)
680     return name;
681 
682   name = GetAttributeValueAsString(cu, DW_AT_linkage_name, nullptr, true);
683   if (name)
684     return name;
685 
686   name = GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
687   return name;
688 }
689 
690 /// This function is builds a table very similar to the standard .debug_aranges
691 /// table, except that the actual DIE offset for the function is placed in the
692 /// table instead of the compile unit offset.
693 void DWARFDebugInfoEntry::BuildFunctionAddressRangeTable(
694     DWARFUnit *cu, DWARFDebugAranges *debug_aranges) const {
695   if (m_tag) {
696     if (m_tag == DW_TAG_subprogram) {
697       DWARFRangeList ranges;
698       GetAttributeAddressRanges(cu, ranges,
699                                 /*check_hi_lo_pc=*/true);
700       for (const auto &r : ranges) {
701         debug_aranges->AppendRange(GetOffset(), r.GetRangeBase(),
702                                    r.GetRangeEnd());
703       }
704     }
705 
706     const DWARFDebugInfoEntry *child = GetFirstChild();
707     while (child) {
708       child->BuildFunctionAddressRangeTable(cu, debug_aranges);
709       child = child->GetSibling();
710     }
711   }
712 }
713 
714 DWARFDeclContext
715 DWARFDebugInfoEntry::GetDWARFDeclContextStatic(const DWARFDebugInfoEntry *die,
716                                                DWARFUnit *cu) {
717   DWARFDeclContext dwarf_decl_ctx;
718   for (;;) {
719     const dw_tag_t tag = die->Tag();
720     if (tag == DW_TAG_compile_unit || tag == DW_TAG_partial_unit)
721       return dwarf_decl_ctx;
722     dwarf_decl_ctx.AppendDeclContext(tag, die->GetName(cu));
723     DWARFDIE parent_decl_ctx_die = die->GetParentDeclContextDIE(cu);
724     if (!parent_decl_ctx_die || parent_decl_ctx_die.GetDIE() == die)
725       return dwarf_decl_ctx;
726     if (parent_decl_ctx_die.Tag() == DW_TAG_compile_unit ||
727         parent_decl_ctx_die.Tag() == DW_TAG_partial_unit)
728       return dwarf_decl_ctx;
729     die = parent_decl_ctx_die.GetDIE();
730     cu = parent_decl_ctx_die.GetCU();
731   }
732 }
733 
734 DWARFDeclContext DWARFDebugInfoEntry::GetDWARFDeclContext(DWARFUnit *cu) const {
735   return GetDWARFDeclContextStatic(this, cu);
736 }
737 
738 DWARFDIE
739 DWARFDebugInfoEntry::GetParentDeclContextDIE(DWARFUnit *cu) const {
740   DWARFAttributes attributes;
741   GetAttributes(cu, attributes, Recurse::yes);
742   return GetParentDeclContextDIE(cu, attributes);
743 }
744 
745 DWARFDIE
746 DWARFDebugInfoEntry::GetParentDeclContextDIE(
747     DWARFUnit *cu, const DWARFAttributes &attributes) const {
748   DWARFDIE die(cu, const_cast<DWARFDebugInfoEntry *>(this));
749 
750   while (die) {
751     // If this is the original DIE that we are searching for a declaration for,
752     // then don't look in the cache as we don't want our own decl context to be
753     // our decl context...
754     if (die.GetDIE() != this) {
755       switch (die.Tag()) {
756       case DW_TAG_compile_unit:
757       case DW_TAG_partial_unit:
758       case DW_TAG_namespace:
759       case DW_TAG_structure_type:
760       case DW_TAG_union_type:
761       case DW_TAG_class_type:
762         return die;
763 
764       default:
765         break;
766       }
767     }
768 
769     DWARFDIE spec_die = attributes.FormValueAsReference(DW_AT_specification);
770     if (spec_die) {
771       DWARFDIE decl_ctx_die = spec_die.GetParentDeclContextDIE();
772       if (decl_ctx_die)
773         return decl_ctx_die;
774     }
775 
776     DWARFDIE abs_die = attributes.FormValueAsReference(DW_AT_abstract_origin);
777     if (abs_die) {
778       DWARFDIE decl_ctx_die = abs_die.GetParentDeclContextDIE();
779       if (decl_ctx_die)
780         return decl_ctx_die;
781     }
782 
783     die = die.GetParent();
784   }
785   return DWARFDIE();
786 }
787 
788 const char *DWARFDebugInfoEntry::GetQualifiedName(DWARFUnit *cu,
789                                                   std::string &storage) const {
790   DWARFAttributes attributes;
791   GetAttributes(cu, attributes, Recurse::yes);
792   return GetQualifiedName(cu, attributes, storage);
793 }
794 
795 const char *
796 DWARFDebugInfoEntry::GetQualifiedName(DWARFUnit *cu,
797                                       const DWARFAttributes &attributes,
798                                       std::string &storage) const {
799 
800   const char *name = GetName(cu);
801 
802   if (name) {
803     DWARFDIE parent_decl_ctx_die = GetParentDeclContextDIE(cu);
804     storage.clear();
805     // TODO: change this to get the correct decl context parent....
806     while (parent_decl_ctx_die) {
807       const dw_tag_t parent_tag = parent_decl_ctx_die.Tag();
808       switch (parent_tag) {
809       case DW_TAG_namespace: {
810         const char *namespace_name = parent_decl_ctx_die.GetName();
811         if (namespace_name) {
812           storage.insert(0, "::");
813           storage.insert(0, namespace_name);
814         } else {
815           storage.insert(0, "(anonymous namespace)::");
816         }
817         parent_decl_ctx_die = parent_decl_ctx_die.GetParentDeclContextDIE();
818       } break;
819 
820       case DW_TAG_class_type:
821       case DW_TAG_structure_type:
822       case DW_TAG_union_type: {
823         const char *class_union_struct_name = parent_decl_ctx_die.GetName();
824 
825         if (class_union_struct_name) {
826           storage.insert(0, "::");
827           storage.insert(0, class_union_struct_name);
828         }
829         parent_decl_ctx_die = parent_decl_ctx_die.GetParentDeclContextDIE();
830       } break;
831 
832       default:
833         parent_decl_ctx_die.Clear();
834         break;
835       }
836     }
837 
838     if (storage.empty())
839       storage.append("::");
840 
841     storage.append(name);
842   }
843   if (storage.empty())
844     return nullptr;
845   return storage.c_str();
846 }
847 
848 lldb::offset_t DWARFDebugInfoEntry::GetFirstAttributeOffset() const {
849   return GetOffset() + llvm::getULEB128Size(m_abbr_idx);
850 }
851 
852 const DWARFAbbreviationDeclaration *
853 DWARFDebugInfoEntry::GetAbbreviationDeclarationPtr(const DWARFUnit *cu) const {
854   if (cu) {
855     const DWARFAbbreviationDeclarationSet *abbrev_set = cu->GetAbbreviations();
856     if (abbrev_set)
857       return abbrev_set->GetAbbreviationDeclaration(m_abbr_idx);
858   }
859   return nullptr;
860 }
861 
862 bool DWARFDebugInfoEntry::IsGlobalOrStaticScopeVariable() const {
863   if (Tag() != DW_TAG_variable)
864     return false;
865   const DWARFDebugInfoEntry *parent_die = GetParent();
866   while (parent_die != nullptr) {
867     switch (parent_die->Tag()) {
868     case DW_TAG_subprogram:
869     case DW_TAG_lexical_block:
870     case DW_TAG_inlined_subroutine:
871       return false;
872 
873     case DW_TAG_compile_unit:
874     case DW_TAG_partial_unit:
875       return true;
876 
877     default:
878       break;
879     }
880     parent_die = parent_die->GetParent();
881   }
882   return false;
883 }
884 
885 bool DWARFDebugInfoEntry::operator==(const DWARFDebugInfoEntry &rhs) const {
886   return m_offset == rhs.m_offset && m_parent_idx == rhs.m_parent_idx &&
887          m_sibling_idx == rhs.m_sibling_idx &&
888          m_abbr_idx == rhs.m_abbr_idx && m_has_children == rhs.m_has_children &&
889          m_tag == rhs.m_tag;
890 }
891 
892 bool DWARFDebugInfoEntry::operator!=(const DWARFDebugInfoEntry &rhs) const {
893   return !(*this == rhs);
894 }
895