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