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 "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 "DWARFUnit.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 "SymbolFileDWARF.h"
30 #include "SymbolFileDWARFDwo.h"
31 
32 using namespace lldb_private;
33 using namespace std;
34 extern int g_verbose;
35 
36 // Extract a debug info entry for a given DWARFUnit from the data
37 // starting at the offset in offset_ptr
38 bool DWARFDebugInfoEntry::Extract(const DWARFDataExtractor &data,
39                                   const DWARFUnit *cu,
40                                   lldb::offset_t *offset_ptr) {
41   m_offset = *offset_ptr;
42   m_parent_idx = 0;
43   m_sibling_idx = 0;
44   const uint64_t abbr_idx = data.GetULEB128(offset_ptr);
45   lldbassert(abbr_idx <= UINT16_MAX);
46   m_abbr_idx = abbr_idx;
47 
48   // assert (fixed_form_sizes);  // For best performance this should be
49   // specified!
50 
51   if (m_abbr_idx) {
52     lldb::offset_t offset = *offset_ptr;
53     auto *abbrevDecl = GetAbbreviationDeclarationPtr(cu);
54     if (abbrevDecl == nullptr) {
55       cu->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
56           "{0x%8.8x}: invalid abbreviation code %u, please file a bug and "
57           "attach the file at the start of this error message",
58           m_offset, (unsigned)abbr_idx);
59       // WE can't parse anymore if the DWARF is borked...
60       *offset_ptr = UINT32_MAX;
61       return false;
62     }
63     m_tag = abbrevDecl->Tag();
64     m_has_children = abbrevDecl->HasChildren();
65     // Skip all data in the .debug_info or .debug_types for the attributes
66     const uint32_t numAttributes = abbrevDecl->NumAttributes();
67     uint32_t i;
68     dw_form_t form;
69     for (i = 0; i < numAttributes; ++i) {
70       form = abbrevDecl->GetFormByIndexUnchecked(i);
71       llvm::Optional<uint8_t> fixed_skip_size =
72           DWARFFormValue::GetFixedSize(form, cu);
73       if (fixed_skip_size)
74         offset += *fixed_skip_size;
75       else {
76         bool form_is_indirect = false;
77         do {
78           form_is_indirect = false;
79           uint32_t form_size = 0;
80           switch (form) {
81           // Blocks if inlined data that have a length field and the data bytes
82           // inlined in the .debug_info/.debug_types
83           case DW_FORM_exprloc:
84           case DW_FORM_block:
85             form_size = data.GetULEB128(&offset);
86             break;
87           case DW_FORM_block1:
88             form_size = data.GetU8_unchecked(&offset);
89             break;
90           case DW_FORM_block2:
91             form_size = data.GetU16_unchecked(&offset);
92             break;
93           case DW_FORM_block4:
94             form_size = data.GetU32_unchecked(&offset);
95             break;
96 
97           // Inlined NULL terminated C-strings
98           case DW_FORM_string:
99             data.GetCStr(&offset);
100             break;
101 
102           // Compile unit address sized values
103           case DW_FORM_addr:
104             form_size = cu->GetAddressByteSize();
105             break;
106           case DW_FORM_ref_addr:
107             if (cu->GetVersion() <= 2)
108               form_size = cu->GetAddressByteSize();
109             else
110               form_size = 4;
111             break;
112 
113           // 0 sized form
114           case DW_FORM_flag_present:
115             form_size = 0;
116             break;
117 
118           // 1 byte values
119           case DW_FORM_addrx1:
120           case DW_FORM_data1:
121           case DW_FORM_flag:
122           case DW_FORM_ref1:
123           case DW_FORM_strx1:
124             form_size = 1;
125             break;
126 
127           // 2 byte values
128           case DW_FORM_addrx2:
129           case DW_FORM_data2:
130           case DW_FORM_ref2:
131           case DW_FORM_strx2:
132             form_size = 2;
133             break;
134 
135           // 3 byte values
136           case DW_FORM_addrx3:
137           case DW_FORM_strx3:
138             form_size = 3;
139             break;
140 
141           // 4 byte values
142           case DW_FORM_addrx4:
143           case DW_FORM_data4:
144           case DW_FORM_ref4:
145           case DW_FORM_strx4:
146             form_size = 4;
147             break;
148 
149           // 8 byte values
150           case DW_FORM_data8:
151           case DW_FORM_ref8:
152           case DW_FORM_ref_sig8:
153             form_size = 8;
154             break;
155 
156           // signed or unsigned LEB 128 values
157           case DW_FORM_addrx:
158           case DW_FORM_rnglistx:
159           case DW_FORM_sdata:
160           case DW_FORM_udata:
161           case DW_FORM_ref_udata:
162           case DW_FORM_GNU_addr_index:
163           case DW_FORM_GNU_str_index:
164           case DW_FORM_strx:
165             data.Skip_LEB128(&offset);
166             break;
167 
168           case DW_FORM_indirect:
169             form_is_indirect = true;
170             form = data.GetULEB128(&offset);
171             break;
172 
173           case DW_FORM_strp:
174           case DW_FORM_sec_offset:
175             data.GetU32(&offset);
176             break;
177 
178           case DW_FORM_implicit_const:
179             form_size = 0;
180             break;
181 
182           default:
183             *offset_ptr = m_offset;
184             return false;
185           }
186           offset += form_size;
187 
188         } while (form_is_indirect);
189       }
190     }
191     *offset_ptr = offset;
192     return true;
193   } else {
194     m_tag = 0;
195     m_has_children = false;
196     return true; // NULL debug tag entry
197   }
198 
199   return false;
200 }
201 
202 static DWARFRangeList GetRangesOrReportError(const DWARFUnit &unit,
203                                              const DWARFDebugInfoEntry &die,
204                                              const DWARFFormValue &value) {
205   llvm::Expected<DWARFRangeList> expected_ranges =
206       (value.Form() == DW_FORM_rnglistx)
207           ? unit.FindRnglistFromIndex(value.Unsigned())
208           : unit.FindRnglistFromOffset(value.Unsigned());
209   if (expected_ranges)
210     return std::move(*expected_ranges);
211   unit.GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
212       "{0x%8.8x}: DIE has DW_AT_ranges(0x%" PRIx64 ") attribute, but "
213       "range extraction failed (%s), please file a bug "
214       "and attach the file at the start of this error message",
215       die.GetOffset(), value.Unsigned(),
216       toString(expected_ranges.takeError()).c_str());
217   return DWARFRangeList();
218 }
219 
220 // GetDIENamesAndRanges
221 //
222 // Gets the valid address ranges for a given DIE by looking for a
223 // DW_AT_low_pc/DW_AT_high_pc pair, DW_AT_entry_pc, or DW_AT_ranges attributes.
224 bool DWARFDebugInfoEntry::GetDIENamesAndRanges(
225     const DWARFUnit *cu, const char *&name, const char *&mangled,
226     DWARFRangeList &ranges, int &decl_file, int &decl_line, int &decl_column,
227     int &call_file, int &call_line, int &call_column,
228     DWARFExpression *frame_base) const {
229   SymbolFileDWARFDwo *dwo_symbol_file = cu->GetDwoSymbolFile();
230   if (dwo_symbol_file)
231     return GetDIENamesAndRanges(
232         dwo_symbol_file->GetCompileUnit(), name, mangled, ranges, decl_file,
233         decl_line, decl_column, call_file, call_line, call_column, frame_base);
234 
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   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(module, data, cu,
349                                             block_offset, block_length);
350             } else {
351               const DWARFDataExtractor &debug_loc_data = dwarf.DebugLocData();
352               const dw_offset_t debug_loc_offset = form_value.Unsigned();
353 
354               size_t loc_list_length = DWARFExpression::LocationListSize(
355                   cu, debug_loc_data, debug_loc_offset);
356               if (loc_list_length > 0) {
357                 *frame_base =
358                     DWARFExpression(module, debug_loc_data, cu,
359                                     debug_loc_offset, loc_list_length);
360                 if (lo_pc != LLDB_INVALID_ADDRESS) {
361                   assert(lo_pc >= cu->GetBaseAddress());
362                   frame_base->SetLocationListSlide(lo_pc -
363                                                    cu->GetBaseAddress());
364                 } else {
365                   set_frame_base_loclist_addr = true;
366                 }
367               }
368             }
369           }
370           break;
371 
372         default:
373           break;
374         }
375       }
376     }
377   }
378 
379   if (ranges.IsEmpty()) {
380     if (lo_pc != LLDB_INVALID_ADDRESS) {
381       if (hi_pc != LLDB_INVALID_ADDRESS && hi_pc > lo_pc)
382         ranges.Append(DWARFRangeList::Entry(lo_pc, hi_pc - lo_pc));
383       else
384         ranges.Append(DWARFRangeList::Entry(lo_pc, 0));
385     }
386   }
387 
388   if (set_frame_base_loclist_addr) {
389     dw_addr_t lowest_range_pc = ranges.GetMinRangeBase(0);
390     assert(lowest_range_pc >= cu->GetBaseAddress());
391     frame_base->SetLocationListSlide(lowest_range_pc - cu->GetBaseAddress());
392   }
393 
394   if (ranges.IsEmpty() || name == nullptr || mangled == nullptr) {
395     for (const DWARFDIE &die : dies) {
396       if (die) {
397         die.GetDIE()->GetDIENamesAndRanges(die.GetCU(), name, mangled, ranges,
398                                            decl_file, decl_line, decl_column,
399                                            call_file, call_line, call_column);
400       }
401     }
402   }
403   return !ranges.IsEmpty();
404 }
405 
406 // Dump
407 //
408 // Dumps a debug information entry and all of it's attributes to the specified
409 // stream.
410 void DWARFDebugInfoEntry::Dump(const DWARFUnit *cu, Stream &s,
411                                uint32_t recurse_depth) const {
412   const DWARFDataExtractor &data = cu->GetData();
413   lldb::offset_t offset = m_offset;
414 
415   if (data.ValidOffset(offset)) {
416     dw_uleb128_t abbrCode = data.GetULEB128(&offset);
417 
418     s.Printf("\n0x%8.8x: ", m_offset);
419     s.Indent();
420     if (abbrCode != m_abbr_idx) {
421       s.Printf("error: DWARF has been modified\n");
422     } else if (abbrCode) {
423       auto *abbrevDecl = GetAbbreviationDeclarationPtr(cu);
424       if (abbrevDecl) {
425         s.PutCString(DW_TAG_value_to_name(abbrevDecl->Tag()));
426         s.Printf(" [%u] %c\n", abbrCode, abbrevDecl->HasChildren() ? '*' : ' ');
427 
428         // Dump all data in the .debug_info/.debug_types for the attributes
429         const uint32_t numAttributes = abbrevDecl->NumAttributes();
430         for (uint32_t i = 0; i < numAttributes; ++i) {
431           DWARFFormValue form_value(cu);
432           dw_attr_t attr;
433           abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
434 
435           DumpAttribute(cu, data, &offset, s, attr, form_value);
436         }
437 
438         const DWARFDebugInfoEntry *child = GetFirstChild();
439         if (recurse_depth > 0 && child) {
440           s.IndentMore();
441 
442           while (child) {
443             child->Dump(cu, s, recurse_depth - 1);
444             child = child->GetSibling();
445           }
446           s.IndentLess();
447         }
448       } else
449         s.Printf("Abbreviation code note found in 'debug_abbrev' class for "
450                  "code: %u\n",
451                  abbrCode);
452     } else {
453       s.Printf("NULL\n");
454     }
455   }
456 }
457 
458 // DumpAttribute
459 //
460 // Dumps a debug information entry attribute along with it's form. Any special
461 // display of attributes is done (disassemble location lists, show enumeration
462 // values for attributes, etc).
463 void DWARFDebugInfoEntry::DumpAttribute(
464     const DWARFUnit *cu, const DWARFDataExtractor &data,
465     lldb::offset_t *offset_ptr, Stream &s, dw_attr_t attr,
466     DWARFFormValue &form_value) {
467   bool show_form = s.GetFlags().Test(DWARFDebugInfo::eDumpFlag_ShowForm);
468 
469   s.Printf("            ");
470   s.Indent(DW_AT_value_to_name(attr));
471 
472   if (show_form) {
473     s.Printf("[%s", DW_FORM_value_to_name(form_value.Form()));
474   }
475 
476   if (!form_value.ExtractValue(data, offset_ptr))
477     return;
478 
479   if (show_form) {
480     if (form_value.Form() == DW_FORM_indirect) {
481       s.Printf(" [%s]", DW_FORM_value_to_name(form_value.Form()));
482     }
483 
484     s.PutCString("] ");
485   }
486 
487   s.PutCString("( ");
488 
489   SymbolFileDWARF &dwarf = cu->GetSymbolFileDWARF();
490 
491   // Check to see if we have any special attribute formatters
492   switch (attr) {
493   case DW_AT_stmt_list:
494     s.Printf("0x%8.8" PRIx64, form_value.Unsigned());
495     break;
496 
497   case DW_AT_language:
498     s.PutCString(DW_LANG_value_to_name(form_value.Unsigned()));
499     break;
500 
501   case DW_AT_encoding:
502     s.PutCString(DW_ATE_value_to_name(form_value.Unsigned()));
503     break;
504 
505   case DW_AT_frame_base:
506   case DW_AT_location:
507   case DW_AT_data_member_location: {
508     const uint8_t *blockData = form_value.BlockData();
509     if (blockData) {
510       // Location description is inlined in data in the form value
511       DWARFDataExtractor locationData(data,
512                                       (*offset_ptr) - form_value.Unsigned(),
513                                       form_value.Unsigned());
514       DWARFExpression::PrintDWARFExpression(
515           s, locationData, DWARFUnit::GetAddressByteSize(cu), 4, false);
516     } else {
517       // We have a location list offset as the value that is the offset into
518       // the .debug_loc section that describes the value over it's lifetime
519       uint64_t debug_loc_offset = form_value.Unsigned();
520       DWARFExpression::PrintDWARFLocationList(s, cu, dwarf.DebugLocData(),
521                                               debug_loc_offset);
522     }
523   } break;
524 
525   case DW_AT_abstract_origin:
526   case DW_AT_specification: {
527     DWARFDIE abstract_die = form_value.Reference();
528     form_value.Dump(s);
529     //  *ostrm_ptr << HEX32 << abstract_die.GetOffset() << " ( ";
530     abstract_die.GetName(s);
531   } break;
532 
533   case DW_AT_type: {
534     DWARFDIE type_die = form_value.Reference();
535     s.PutCString(" ( ");
536     type_die.AppendTypeName(s);
537     s.PutCString(" )");
538   } break;
539 
540   default:
541     break;
542   }
543 
544   s.PutCString(" )\n");
545 }
546 
547 // Get all attribute values for a given DIE, including following any
548 // specification or abstract origin attributes and including those in the
549 // results. Any duplicate attributes will have the first instance take
550 // precedence (this can happen for declaration attributes).
551 size_t DWARFDebugInfoEntry::GetAttributes(
552     const DWARFUnit *cu, DWARFAttributes &attributes,
553     uint32_t curr_depth) const {
554   auto abbrevDecl = GetAbbreviationDeclarationPtr(cu);
555   if (abbrevDecl) {
556     const DWARFDataExtractor &data = cu->GetData();
557     lldb::offset_t offset = GetFirstAttributeOffset();
558 
559     const uint32_t num_attributes = abbrevDecl->NumAttributes();
560     for (uint32_t i = 0; i < num_attributes; ++i) {
561       DWARFFormValue form_value(cu);
562       dw_attr_t attr;
563       abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
564       const dw_form_t form = form_value.Form();
565 
566       // If we are tracking down DW_AT_specification or DW_AT_abstract_origin
567       // attributes, the depth will be non-zero. We need to omit certain
568       // attributes that don't make sense.
569       switch (attr) {
570       case DW_AT_sibling:
571       case DW_AT_declaration:
572         if (curr_depth > 0) {
573           // This attribute doesn't make sense when combined with the DIE that
574           // references this DIE. We know a DIE is referencing this DIE because
575           // curr_depth is not zero
576           break;
577         }
578         LLVM_FALLTHROUGH;
579       default:
580         attributes.Append(cu, offset, attr, form);
581         break;
582       }
583 
584       if ((attr == DW_AT_specification) || (attr == DW_AT_abstract_origin)) {
585         if (form_value.ExtractValue(data, &offset)) {
586           DWARFDIE spec_die = form_value.Reference();
587           if (spec_die)
588             spec_die.GetAttributes(attributes, curr_depth + 1);
589         }
590       } else {
591         llvm::Optional<uint8_t> fixed_skip_size = DWARFFormValue::GetFixedSize(form, cu);
592         if (fixed_skip_size)
593           offset += *fixed_skip_size;
594         else
595           DWARFFormValue::SkipValue(form, data, &offset, cu);
596       }
597     }
598   } else {
599     attributes.Clear();
600   }
601   return attributes.Size();
602 }
603 
604 // GetAttributeValue
605 //
606 // Get the value of an attribute and return the .debug_info or .debug_types
607 // offset of the attribute if it was properly extracted into form_value,
608 // or zero if we fail since an offset of zero is invalid for an attribute (it
609 // would be a compile unit header).
610 dw_offset_t DWARFDebugInfoEntry::GetAttributeValue(
611     const DWARFUnit *cu, const dw_attr_t attr, DWARFFormValue &form_value,
612     dw_offset_t *end_attr_offset_ptr,
613     bool check_specification_or_abstract_origin) const {
614   SymbolFileDWARFDwo *dwo_symbol_file = cu->GetDwoSymbolFile();
615   if (dwo_symbol_file && m_tag != DW_TAG_compile_unit &&
616                          m_tag != DW_TAG_partial_unit)
617     return GetAttributeValue(dwo_symbol_file->GetCompileUnit(), attr,
618                              form_value, end_attr_offset_ptr,
619                              check_specification_or_abstract_origin);
620 
621   auto abbrevDecl = GetAbbreviationDeclarationPtr(cu);
622 
623   if (abbrevDecl) {
624     uint32_t attr_idx = abbrevDecl->FindAttributeIndex(attr);
625 
626     if (attr_idx != DW_INVALID_INDEX) {
627       const DWARFDataExtractor &data = cu->GetData();
628       lldb::offset_t offset = GetFirstAttributeOffset();
629 
630       uint32_t idx = 0;
631       while (idx < attr_idx)
632         DWARFFormValue::SkipValue(abbrevDecl->GetFormByIndex(idx++),
633                                   data, &offset, cu);
634 
635       const dw_offset_t attr_offset = offset;
636       form_value.SetUnit(cu);
637       form_value.SetForm(abbrevDecl->GetFormByIndex(idx));
638       if (form_value.ExtractValue(data, &offset)) {
639         if (end_attr_offset_ptr)
640           *end_attr_offset_ptr = offset;
641         return attr_offset;
642       }
643     }
644   }
645 
646   if (check_specification_or_abstract_origin) {
647     if (GetAttributeValue(cu, DW_AT_specification, form_value)) {
648       DWARFDIE die = form_value.Reference();
649       if (die) {
650         dw_offset_t die_offset = die.GetDIE()->GetAttributeValue(
651             die.GetCU(), attr, form_value, end_attr_offset_ptr, false);
652         if (die_offset)
653           return die_offset;
654       }
655     }
656 
657     if (GetAttributeValue(cu, DW_AT_abstract_origin, form_value)) {
658       DWARFDIE die = form_value.Reference();
659       if (die) {
660         dw_offset_t die_offset = die.GetDIE()->GetAttributeValue(
661             die.GetCU(), attr, form_value, end_attr_offset_ptr, false);
662         if (die_offset)
663           return die_offset;
664       }
665     }
666   }
667 
668   if (!dwo_symbol_file)
669     return 0;
670 
671   DWARFUnit *dwo_cu = dwo_symbol_file->GetCompileUnit();
672   if (!dwo_cu)
673     return 0;
674 
675   DWARFBaseDIE dwo_cu_die = dwo_cu->GetUnitDIEOnly();
676   if (!dwo_cu_die.IsValid())
677     return 0;
678 
679   return dwo_cu_die.GetDIE()->GetAttributeValue(
680       dwo_cu, attr, form_value, end_attr_offset_ptr,
681       check_specification_or_abstract_origin);
682 }
683 
684 // GetAttributeValueAsString
685 //
686 // Get the value of an attribute as a string return it. The resulting pointer
687 // to the string data exists within the supplied SymbolFileDWARF and will only
688 // be available as long as the SymbolFileDWARF is still around and it's content
689 // doesn't change.
690 const char *DWARFDebugInfoEntry::GetAttributeValueAsString(
691     const DWARFUnit *cu, const dw_attr_t attr, const char *fail_value,
692     bool check_specification_or_abstract_origin) const {
693   DWARFFormValue form_value;
694   if (GetAttributeValue(cu, attr, form_value, nullptr,
695                         check_specification_or_abstract_origin))
696     return form_value.AsCString();
697   return fail_value;
698 }
699 
700 // GetAttributeValueAsUnsigned
701 //
702 // Get the value of an attribute as unsigned and return it.
703 uint64_t DWARFDebugInfoEntry::GetAttributeValueAsUnsigned(
704     const DWARFUnit *cu, const dw_attr_t attr, uint64_t fail_value,
705     bool check_specification_or_abstract_origin) const {
706   DWARFFormValue form_value;
707   if (GetAttributeValue(cu, attr, form_value, nullptr,
708                         check_specification_or_abstract_origin))
709     return form_value.Unsigned();
710   return fail_value;
711 }
712 
713 // GetAttributeValueAsReference
714 //
715 // Get the value of an attribute as reference and fix up and compile unit
716 // relative offsets as needed.
717 DWARFDIE DWARFDebugInfoEntry::GetAttributeValueAsReference(
718     const DWARFUnit *cu, const dw_attr_t attr,
719     bool check_specification_or_abstract_origin) const {
720   DWARFFormValue form_value;
721   if (GetAttributeValue(cu, attr, form_value, nullptr,
722                         check_specification_or_abstract_origin))
723     return form_value.Reference();
724   return {};
725 }
726 
727 uint64_t DWARFDebugInfoEntry::GetAttributeValueAsAddress(
728     const DWARFUnit *cu, const dw_attr_t attr, uint64_t fail_value,
729     bool check_specification_or_abstract_origin) const {
730   DWARFFormValue form_value;
731   if (GetAttributeValue(cu, attr, form_value, nullptr,
732                         check_specification_or_abstract_origin))
733     return form_value.Address();
734   return fail_value;
735 }
736 
737 // GetAttributeHighPC
738 //
739 // Get the hi_pc, adding hi_pc to lo_pc when specified as an <offset-from-low-
740 // pc>.
741 //
742 // Returns the hi_pc or fail_value.
743 dw_addr_t DWARFDebugInfoEntry::GetAttributeHighPC(
744     const DWARFUnit *cu, dw_addr_t lo_pc, uint64_t fail_value,
745     bool check_specification_or_abstract_origin) const {
746   DWARFFormValue form_value;
747   if (GetAttributeValue(cu, DW_AT_high_pc, form_value, nullptr,
748                         check_specification_or_abstract_origin)) {
749     dw_form_t form = form_value.Form();
750     if (form == DW_FORM_addr || form == DW_FORM_addrx ||
751         form == DW_FORM_GNU_addr_index)
752       return form_value.Address();
753 
754     // DWARF4 can specify the hi_pc as an <offset-from-lowpc>
755     return lo_pc + form_value.Unsigned();
756   }
757   return fail_value;
758 }
759 
760 // GetAttributeAddressRange
761 //
762 // Get the lo_pc and hi_pc, adding hi_pc to lo_pc when specified as an <offset-
763 // from-low-pc>.
764 //
765 // Returns true or sets lo_pc and hi_pc to fail_value.
766 bool DWARFDebugInfoEntry::GetAttributeAddressRange(
767     const DWARFUnit *cu, dw_addr_t &lo_pc, dw_addr_t &hi_pc,
768     uint64_t fail_value, bool check_specification_or_abstract_origin) const {
769   lo_pc = GetAttributeValueAsAddress(cu, DW_AT_low_pc, fail_value,
770                                      check_specification_or_abstract_origin);
771   if (lo_pc != fail_value) {
772     hi_pc = GetAttributeHighPC(cu, lo_pc, fail_value,
773                                check_specification_or_abstract_origin);
774     if (hi_pc != fail_value)
775       return true;
776   }
777   lo_pc = fail_value;
778   hi_pc = fail_value;
779   return false;
780 }
781 
782 size_t DWARFDebugInfoEntry::GetAttributeAddressRanges(
783     const DWARFUnit *cu, DWARFRangeList &ranges, bool check_hi_lo_pc,
784     bool check_specification_or_abstract_origin) const {
785   ranges.Clear();
786 
787   DWARFFormValue form_value;
788   if (GetAttributeValue(cu, DW_AT_ranges, form_value)) {
789     ranges = GetRangesOrReportError(*cu, *this, form_value);
790   } else if (check_hi_lo_pc) {
791     dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
792     dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
793     if (GetAttributeAddressRange(cu, lo_pc, hi_pc, LLDB_INVALID_ADDRESS,
794                                  check_specification_or_abstract_origin)) {
795       if (lo_pc < hi_pc)
796         ranges.Append(DWARFRangeList::Entry(lo_pc, hi_pc - lo_pc));
797     }
798   }
799   return ranges.GetSize();
800 }
801 
802 // GetName
803 //
804 // Get value of the DW_AT_name attribute and return it if one exists, else
805 // return NULL.
806 const char *DWARFDebugInfoEntry::GetName(const DWARFUnit *cu) const {
807   return GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
808 }
809 
810 // GetMangledName
811 //
812 // Get value of the DW_AT_MIPS_linkage_name attribute and return it if one
813 // exists, else return the value of the DW_AT_name attribute
814 const char *
815 DWARFDebugInfoEntry::GetMangledName(const DWARFUnit *cu,
816                                     bool substitute_name_allowed) const {
817   const char *name = nullptr;
818 
819   name = GetAttributeValueAsString(cu, DW_AT_MIPS_linkage_name, nullptr, true);
820   if (name)
821     return name;
822 
823   name = GetAttributeValueAsString(cu, DW_AT_linkage_name, nullptr, true);
824   if (name)
825     return name;
826 
827   if (!substitute_name_allowed)
828     return nullptr;
829 
830   name = GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
831   return name;
832 }
833 
834 // GetPubname
835 //
836 // Get value the name for a DIE as it should appear for a .debug_pubnames or
837 // .debug_pubtypes section.
838 const char *DWARFDebugInfoEntry::GetPubname(const DWARFUnit *cu) const {
839   const char *name = nullptr;
840   if (!cu)
841     return name;
842 
843   name = GetAttributeValueAsString(cu, DW_AT_MIPS_linkage_name, nullptr, true);
844   if (name)
845     return name;
846 
847   name = GetAttributeValueAsString(cu, DW_AT_linkage_name, nullptr, true);
848   if (name)
849     return name;
850 
851   name = GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
852   return name;
853 }
854 
855 // BuildAddressRangeTable
856 void DWARFDebugInfoEntry::BuildAddressRangeTable(
857     const DWARFUnit *cu, DWARFDebugAranges *debug_aranges) const {
858   if (m_tag) {
859     if (m_tag == DW_TAG_subprogram) {
860       dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
861       dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
862       if (GetAttributeAddressRange(cu, lo_pc, hi_pc, LLDB_INVALID_ADDRESS)) {
863         /// printf("BuildAddressRangeTable() 0x%8.8x: %30s: [0x%8.8x -
864         /// 0x%8.8x)\n", m_offset, DW_TAG_value_to_name(tag), lo_pc, hi_pc);
865         debug_aranges->AppendRange(cu->GetOffset(), lo_pc, hi_pc);
866       }
867     }
868 
869     const DWARFDebugInfoEntry *child = GetFirstChild();
870     while (child) {
871       child->BuildAddressRangeTable(cu, debug_aranges);
872       child = child->GetSibling();
873     }
874   }
875 }
876 
877 // BuildFunctionAddressRangeTable
878 //
879 // This function is very similar to the BuildAddressRangeTable function except
880 // that the actual DIE offset for the function is placed in the table instead
881 // of the compile unit offset (which is the way the standard .debug_aranges
882 // section does it).
883 void DWARFDebugInfoEntry::BuildFunctionAddressRangeTable(
884     const DWARFUnit *cu, DWARFDebugAranges *debug_aranges) const {
885   if (m_tag) {
886     if (m_tag == DW_TAG_subprogram) {
887       dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
888       dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
889       if (GetAttributeAddressRange(cu, lo_pc, hi_pc, LLDB_INVALID_ADDRESS)) {
890         //  printf("BuildAddressRangeTable() 0x%8.8x: [0x%16.16" PRIx64 " -
891         //  0x%16.16" PRIx64 ")\n", m_offset, lo_pc, hi_pc); // DEBUG ONLY
892         debug_aranges->AppendRange(GetOffset(), lo_pc, hi_pc);
893       }
894     }
895 
896     const DWARFDebugInfoEntry *child = GetFirstChild();
897     while (child) {
898       child->BuildFunctionAddressRangeTable(cu, debug_aranges);
899       child = child->GetSibling();
900     }
901   }
902 }
903 
904 void DWARFDebugInfoEntry::GetDWARFDeclContext(
905     DWARFUnit *cu, DWARFDeclContext &dwarf_decl_ctx) const {
906   const dw_tag_t tag = Tag();
907   if (tag != DW_TAG_compile_unit && tag != DW_TAG_partial_unit) {
908     dwarf_decl_ctx.AppendDeclContext(tag, GetName(cu));
909     DWARFDIE parent_decl_ctx_die = GetParentDeclContextDIE(cu);
910     if (parent_decl_ctx_die && parent_decl_ctx_die.GetDIE() != this) {
911       if (parent_decl_ctx_die.Tag() != DW_TAG_compile_unit &&
912           parent_decl_ctx_die.Tag() != DW_TAG_partial_unit)
913         parent_decl_ctx_die.GetDIE()->GetDWARFDeclContext(
914             parent_decl_ctx_die.GetCU(), dwarf_decl_ctx);
915     }
916   }
917 }
918 
919 DWARFDIE
920 DWARFDebugInfoEntry::GetParentDeclContextDIE(DWARFUnit *cu) const {
921   DWARFAttributes attributes;
922   GetAttributes(cu, attributes);
923   return GetParentDeclContextDIE(cu, attributes);
924 }
925 
926 DWARFDIE
927 DWARFDebugInfoEntry::GetParentDeclContextDIE(
928     DWARFUnit *cu, const DWARFAttributes &attributes) const {
929   DWARFDIE die(cu, const_cast<DWARFDebugInfoEntry *>(this));
930 
931   while (die) {
932     // If this is the original DIE that we are searching for a declaration for,
933     // then don't look in the cache as we don't want our own decl context to be
934     // our decl context...
935     if (die.GetDIE() != this) {
936       switch (die.Tag()) {
937       case DW_TAG_compile_unit:
938       case DW_TAG_partial_unit:
939       case DW_TAG_namespace:
940       case DW_TAG_structure_type:
941       case DW_TAG_union_type:
942       case DW_TAG_class_type:
943         return die;
944 
945       default:
946         break;
947       }
948     }
949 
950     DWARFDIE spec_die = attributes.FormValueAsReference(DW_AT_specification);
951     if (spec_die) {
952       DWARFDIE decl_ctx_die = spec_die.GetParentDeclContextDIE();
953       if (decl_ctx_die)
954         return decl_ctx_die;
955     }
956 
957     DWARFDIE abs_die = attributes.FormValueAsReference(DW_AT_abstract_origin);
958     if (abs_die) {
959       DWARFDIE decl_ctx_die = abs_die.GetParentDeclContextDIE();
960       if (decl_ctx_die)
961         return decl_ctx_die;
962     }
963 
964     die = die.GetParent();
965   }
966   return DWARFDIE();
967 }
968 
969 const char *DWARFDebugInfoEntry::GetQualifiedName(DWARFUnit *cu,
970                                                   std::string &storage) const {
971   DWARFAttributes attributes;
972   GetAttributes(cu, attributes);
973   return GetQualifiedName(cu, attributes, storage);
974 }
975 
976 const char *
977 DWARFDebugInfoEntry::GetQualifiedName(DWARFUnit *cu,
978                                       const DWARFAttributes &attributes,
979                                       std::string &storage) const {
980 
981   const char *name = GetName(cu);
982 
983   if (name) {
984     DWARFDIE parent_decl_ctx_die = GetParentDeclContextDIE(cu);
985     storage.clear();
986     // TODO: change this to get the correct decl context parent....
987     while (parent_decl_ctx_die) {
988       const dw_tag_t parent_tag = parent_decl_ctx_die.Tag();
989       switch (parent_tag) {
990       case DW_TAG_namespace: {
991         const char *namespace_name = parent_decl_ctx_die.GetName();
992         if (namespace_name) {
993           storage.insert(0, "::");
994           storage.insert(0, namespace_name);
995         } else {
996           storage.insert(0, "(anonymous namespace)::");
997         }
998         parent_decl_ctx_die = parent_decl_ctx_die.GetParentDeclContextDIE();
999       } break;
1000 
1001       case DW_TAG_class_type:
1002       case DW_TAG_structure_type:
1003       case DW_TAG_union_type: {
1004         const char *class_union_struct_name = parent_decl_ctx_die.GetName();
1005 
1006         if (class_union_struct_name) {
1007           storage.insert(0, "::");
1008           storage.insert(0, class_union_struct_name);
1009         }
1010         parent_decl_ctx_die = parent_decl_ctx_die.GetParentDeclContextDIE();
1011       } break;
1012 
1013       default:
1014         parent_decl_ctx_die.Clear();
1015         break;
1016       }
1017     }
1018 
1019     if (storage.empty())
1020       storage.append("::");
1021 
1022     storage.append(name);
1023   }
1024   if (storage.empty())
1025     return nullptr;
1026   return storage.c_str();
1027 }
1028 
1029 bool DWARFDebugInfoEntry::LookupAddress(const dw_addr_t address,
1030                                         const DWARFUnit *cu,
1031                                         DWARFDebugInfoEntry **function_die,
1032                                         DWARFDebugInfoEntry **block_die) {
1033   bool found_address = false;
1034   if (m_tag) {
1035     bool check_children = false;
1036     bool match_addr_range = false;
1037     //  printf("0x%8.8x: %30s: address = 0x%8.8x - ", m_offset,
1038     //  DW_TAG_value_to_name(tag), address);
1039     switch (m_tag) {
1040     case DW_TAG_array_type:
1041       break;
1042     case DW_TAG_class_type:
1043       check_children = true;
1044       break;
1045     case DW_TAG_entry_point:
1046     case DW_TAG_enumeration_type:
1047     case DW_TAG_formal_parameter:
1048     case DW_TAG_imported_declaration:
1049     case DW_TAG_label:
1050       break;
1051     case DW_TAG_lexical_block:
1052       check_children = true;
1053       match_addr_range = true;
1054       break;
1055     case DW_TAG_member:
1056     case DW_TAG_pointer_type:
1057     case DW_TAG_reference_type:
1058       break;
1059     case DW_TAG_compile_unit:
1060       match_addr_range = true;
1061       break;
1062     case DW_TAG_string_type:
1063       break;
1064     case DW_TAG_structure_type:
1065       check_children = true;
1066       break;
1067     case DW_TAG_subroutine_type:
1068     case DW_TAG_typedef:
1069     case DW_TAG_union_type:
1070     case DW_TAG_unspecified_parameters:
1071     case DW_TAG_variant:
1072       break;
1073     case DW_TAG_common_block:
1074       check_children = true;
1075       break;
1076     case DW_TAG_common_inclusion:
1077     case DW_TAG_inheritance:
1078       break;
1079     case DW_TAG_inlined_subroutine:
1080       check_children = true;
1081       match_addr_range = true;
1082       break;
1083     case DW_TAG_module:
1084       match_addr_range = true;
1085       break;
1086     case DW_TAG_ptr_to_member_type:
1087     case DW_TAG_set_type:
1088     case DW_TAG_subrange_type:
1089     case DW_TAG_with_stmt:
1090     case DW_TAG_access_declaration:
1091     case DW_TAG_base_type:
1092       break;
1093     case DW_TAG_catch_block:
1094       match_addr_range = true;
1095       break;
1096     case DW_TAG_const_type:
1097     case DW_TAG_constant:
1098     case DW_TAG_enumerator:
1099     case DW_TAG_file_type:
1100     case DW_TAG_friend:
1101     case DW_TAG_namelist:
1102     case DW_TAG_namelist_item:
1103     case DW_TAG_packed_type:
1104       break;
1105     case DW_TAG_subprogram:
1106       match_addr_range = true;
1107       break;
1108     case DW_TAG_template_type_parameter:
1109     case DW_TAG_template_value_parameter:
1110     case DW_TAG_GNU_template_parameter_pack:
1111     case DW_TAG_thrown_type:
1112       break;
1113     case DW_TAG_try_block:
1114       match_addr_range = true;
1115       break;
1116     case DW_TAG_variant_part:
1117     case DW_TAG_variable:
1118     case DW_TAG_volatile_type:
1119     case DW_TAG_dwarf_procedure:
1120     case DW_TAG_restrict_type:
1121     case DW_TAG_interface_type:
1122       break;
1123     case DW_TAG_namespace:
1124       check_children = true;
1125       break;
1126     case DW_TAG_imported_module:
1127     case DW_TAG_unspecified_type:
1128       break;
1129     case DW_TAG_partial_unit:
1130       match_addr_range = true;
1131       break;
1132     case DW_TAG_imported_unit:
1133     case DW_TAG_shared_type:
1134     default:
1135       break;
1136     }
1137 
1138     if (match_addr_range) {
1139       dw_addr_t lo_pc =
1140           GetAttributeValueAsAddress(cu, DW_AT_low_pc, LLDB_INVALID_ADDRESS);
1141       if (lo_pc != LLDB_INVALID_ADDRESS) {
1142         dw_addr_t hi_pc = GetAttributeHighPC(cu, lo_pc, LLDB_INVALID_ADDRESS);
1143         if (hi_pc != LLDB_INVALID_ADDRESS) {
1144           //  printf("\n0x%8.8x: %30s: address = 0x%8.8x  [0x%8.8x - 0x%8.8x) ",
1145           //  m_offset, DW_TAG_value_to_name(tag), address, lo_pc, hi_pc);
1146           if ((lo_pc <= address) && (address < hi_pc)) {
1147             found_address = true;
1148             //  puts("***MATCH***");
1149             switch (m_tag) {
1150             case DW_TAG_compile_unit: // File
1151             case DW_TAG_partial_unit: // File
1152               check_children =
1153                   ((function_die != nullptr) || (block_die != nullptr));
1154               break;
1155 
1156             case DW_TAG_subprogram: // Function
1157               if (function_die)
1158                 *function_die = this;
1159               check_children = (block_die != nullptr);
1160               break;
1161 
1162             case DW_TAG_inlined_subroutine: // Inlined Function
1163             case DW_TAG_lexical_block:      // Block { } in code
1164               if (block_die) {
1165                 *block_die = this;
1166                 check_children = true;
1167               }
1168               break;
1169 
1170             default:
1171               check_children = true;
1172               break;
1173             }
1174           }
1175         } else {
1176           // Compile units may not have a valid high/low pc when there
1177           // are address gaps in subroutines so we must always search
1178           // if there is no valid high and low PC.
1179           check_children =
1180               (m_tag == DW_TAG_compile_unit || m_tag == DW_TAG_partial_unit) &&
1181               ((function_die != nullptr) || (block_die != nullptr));
1182         }
1183       } else {
1184         DWARFRangeList ranges;
1185         if (GetAttributeAddressRanges(cu, ranges, /*check_hi_lo_pc*/ false) &&
1186             ranges.FindEntryThatContains(address)) {
1187           found_address = true;
1188           //  puts("***MATCH***");
1189           switch (m_tag) {
1190           case DW_TAG_compile_unit: // File
1191           case DW_TAG_partial_unit: // File
1192               check_children =
1193                   ((function_die != nullptr) || (block_die != nullptr));
1194               break;
1195 
1196           case DW_TAG_subprogram: // Function
1197             if (function_die)
1198               *function_die = this;
1199             check_children = (block_die != nullptr);
1200             break;
1201 
1202           case DW_TAG_inlined_subroutine: // Inlined Function
1203           case DW_TAG_lexical_block:      // Block { } in code
1204             if (block_die) {
1205               *block_die = this;
1206               check_children = true;
1207             }
1208             break;
1209 
1210           default:
1211             check_children = true;
1212             break;
1213           }
1214         } else {
1215           check_children = false;
1216         }
1217       }
1218     }
1219 
1220     if (check_children) {
1221       //  printf("checking children\n");
1222       DWARFDebugInfoEntry *child = GetFirstChild();
1223       while (child) {
1224         if (child->LookupAddress(address, cu, function_die, block_die))
1225           return true;
1226         child = child->GetSibling();
1227       }
1228     }
1229   }
1230   return found_address;
1231 }
1232 
1233 lldb::offset_t DWARFDebugInfoEntry::GetFirstAttributeOffset() const {
1234   return GetOffset() + llvm::getULEB128Size(m_abbr_idx);
1235 }
1236 
1237 const DWARFAbbreviationDeclaration *
1238 DWARFDebugInfoEntry::GetAbbreviationDeclarationPtr(const DWARFUnit *cu) const {
1239   if (cu) {
1240     const DWARFAbbreviationDeclarationSet *abbrev_set = cu->GetAbbreviations();
1241     if (abbrev_set)
1242       return abbrev_set->GetAbbreviationDeclaration(m_abbr_idx);
1243   }
1244   return nullptr;
1245 }
1246 
1247 bool DWARFDebugInfoEntry::operator==(const DWARFDebugInfoEntry &rhs) const {
1248   return m_offset == rhs.m_offset && m_parent_idx == rhs.m_parent_idx &&
1249          m_sibling_idx == rhs.m_sibling_idx &&
1250          m_abbr_idx == rhs.m_abbr_idx && m_has_children == rhs.m_has_children &&
1251          m_tag == rhs.m_tag;
1252 }
1253 
1254 bool DWARFDebugInfoEntry::operator!=(const DWARFDebugInfoEntry &rhs) const {
1255   return !(*this == rhs);
1256 }
1257