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<DIERef> die_refs;
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           die_refs.emplace_back(form_value);
306           break;
307 
308         case DW_AT_specification:
309           die_refs.emplace_back(form_value);
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 DIERef &die_ref : die_refs) {
396       if (die_ref.die_offset != DW_INVALID_OFFSET) {
397         DWARFDIE die = dwarf.GetDIE(die_ref);
398         if (die)
399           die.GetDIE()->GetDIENamesAndRanges(die.GetCU(), name, mangled, ranges,
400                                              decl_file, decl_line, decl_column,
401                                              call_file, call_line, call_column);
402       }
403     }
404   }
405   return !ranges.IsEmpty();
406 }
407 
408 // Dump
409 //
410 // Dumps a debug information entry and all of it's attributes to the specified
411 // stream.
412 void DWARFDebugInfoEntry::Dump(const DWARFUnit *cu, Stream &s,
413                                uint32_t recurse_depth) const {
414   const DWARFDataExtractor &data = cu->GetData();
415   lldb::offset_t offset = m_offset;
416 
417   if (data.ValidOffset(offset)) {
418     dw_uleb128_t abbrCode = data.GetULEB128(&offset);
419 
420     s.Printf("\n0x%8.8x: ", m_offset);
421     s.Indent();
422     if (abbrCode != m_abbr_idx) {
423       s.Printf("error: DWARF has been modified\n");
424     } else if (abbrCode) {
425       auto *abbrevDecl = GetAbbreviationDeclarationPtr(cu);
426       if (abbrevDecl) {
427         s.PutCString(DW_TAG_value_to_name(abbrevDecl->Tag()));
428         s.Printf(" [%u] %c\n", abbrCode, abbrevDecl->HasChildren() ? '*' : ' ');
429 
430         // Dump all data in the .debug_info/.debug_types for the attributes
431         const uint32_t numAttributes = abbrevDecl->NumAttributes();
432         for (uint32_t i = 0; i < numAttributes; ++i) {
433           DWARFFormValue form_value(cu);
434           dw_attr_t attr;
435           abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
436 
437           DumpAttribute(cu, data, &offset, s, attr, form_value);
438         }
439 
440         const DWARFDebugInfoEntry *child = GetFirstChild();
441         if (recurse_depth > 0 && child) {
442           s.IndentMore();
443 
444           while (child) {
445             child->Dump(cu, s, recurse_depth - 1);
446             child = child->GetSibling();
447           }
448           s.IndentLess();
449         }
450       } else
451         s.Printf("Abbreviation code note found in 'debug_abbrev' class for "
452                  "code: %u\n",
453                  abbrCode);
454     } else {
455       s.Printf("NULL\n");
456     }
457   }
458 }
459 
460 // DumpAttribute
461 //
462 // Dumps a debug information entry attribute along with it's form. Any special
463 // display of attributes is done (disassemble location lists, show enumeration
464 // values for attributes, etc).
465 void DWARFDebugInfoEntry::DumpAttribute(
466     const DWARFUnit *cu, const DWARFDataExtractor &data,
467     lldb::offset_t *offset_ptr, Stream &s, dw_attr_t attr,
468     DWARFFormValue &form_value) {
469   bool show_form = s.GetFlags().Test(DWARFDebugInfo::eDumpFlag_ShowForm);
470 
471   s.Printf("            ");
472   s.Indent(DW_AT_value_to_name(attr));
473 
474   if (show_form) {
475     s.Printf("[%s", DW_FORM_value_to_name(form_value.Form()));
476   }
477 
478   if (!form_value.ExtractValue(data, offset_ptr))
479     return;
480 
481   if (show_form) {
482     if (form_value.Form() == DW_FORM_indirect) {
483       s.Printf(" [%s]", DW_FORM_value_to_name(form_value.Form()));
484     }
485 
486     s.PutCString("] ");
487   }
488 
489   s.PutCString("( ");
490 
491   SymbolFileDWARF &dwarf = cu->GetSymbolFileDWARF();
492 
493   // Check to see if we have any special attribute formatters
494   switch (attr) {
495   case DW_AT_stmt_list:
496     s.Printf("0x%8.8" PRIx64, form_value.Unsigned());
497     break;
498 
499   case DW_AT_language:
500     s.PutCString(DW_LANG_value_to_name(form_value.Unsigned()));
501     break;
502 
503   case DW_AT_encoding:
504     s.PutCString(DW_ATE_value_to_name(form_value.Unsigned()));
505     break;
506 
507   case DW_AT_frame_base:
508   case DW_AT_location:
509   case DW_AT_data_member_location: {
510     const uint8_t *blockData = form_value.BlockData();
511     if (blockData) {
512       // Location description is inlined in data in the form value
513       DWARFDataExtractor locationData(data,
514                                       (*offset_ptr) - form_value.Unsigned(),
515                                       form_value.Unsigned());
516       DWARFExpression::PrintDWARFExpression(
517           s, locationData, DWARFUnit::GetAddressByteSize(cu), 4, false);
518     } else {
519       // We have a location list offset as the value that is the offset into
520       // the .debug_loc section that describes the value over it's lifetime
521       uint64_t debug_loc_offset = form_value.Unsigned();
522       DWARFExpression::PrintDWARFLocationList(s, cu, dwarf.DebugLocData(),
523                                               debug_loc_offset);
524     }
525   } break;
526 
527   case DW_AT_abstract_origin:
528   case DW_AT_specification: {
529     DWARFDIE abstract_die = form_value.Reference();
530     form_value.Dump(s);
531     //  *ostrm_ptr << HEX32 << abstract_die.GetOffset() << " ( ";
532     abstract_die.GetName(s);
533   } break;
534 
535   case DW_AT_type: {
536     DWARFDIE type_die = form_value.Reference();
537     s.PutCString(" ( ");
538     type_die.AppendTypeName(s);
539     s.PutCString(" )");
540   } break;
541 
542   default:
543     break;
544   }
545 
546   s.PutCString(" )\n");
547 }
548 
549 // Get all attribute values for a given DIE, including following any
550 // specification or abstract origin attributes and including those in the
551 // results. Any duplicate attributes will have the first instance take
552 // precedence (this can happen for declaration attributes).
553 size_t DWARFDebugInfoEntry::GetAttributes(
554     const DWARFUnit *cu, DWARFAttributes &attributes,
555     uint32_t curr_depth) const {
556   auto abbrevDecl = GetAbbreviationDeclarationPtr(cu);
557   if (abbrevDecl) {
558     const DWARFDataExtractor &data = cu->GetData();
559     lldb::offset_t offset = GetFirstAttributeOffset();
560 
561     const uint32_t num_attributes = abbrevDecl->NumAttributes();
562     for (uint32_t i = 0; i < num_attributes; ++i) {
563       DWARFFormValue form_value(cu);
564       dw_attr_t attr;
565       abbrevDecl->GetAttrAndFormValueByIndex(i, attr, form_value);
566       const dw_form_t form = form_value.Form();
567 
568       // If we are tracking down DW_AT_specification or DW_AT_abstract_origin
569       // attributes, the depth will be non-zero. We need to omit certain
570       // attributes that don't make sense.
571       switch (attr) {
572       case DW_AT_sibling:
573       case DW_AT_declaration:
574         if (curr_depth > 0) {
575           // This attribute doesn't make sense when combined with the DIE that
576           // references this DIE. We know a DIE is referencing this DIE because
577           // curr_depth is not zero
578           break;
579         }
580         LLVM_FALLTHROUGH;
581       default:
582         attributes.Append(cu, offset, attr, form);
583         break;
584       }
585 
586       if ((attr == DW_AT_specification) || (attr == DW_AT_abstract_origin)) {
587         if (form_value.ExtractValue(data, &offset)) {
588           DWARFDIE spec_die = form_value.Reference();
589           if (spec_die)
590             spec_die.GetAttributes(attributes, curr_depth + 1);
591         }
592       } else {
593         llvm::Optional<uint8_t> fixed_skip_size = DWARFFormValue::GetFixedSize(form, cu);
594         if (fixed_skip_size)
595           offset += *fixed_skip_size;
596         else
597           DWARFFormValue::SkipValue(form, data, &offset, cu);
598       }
599     }
600   } else {
601     attributes.Clear();
602   }
603   return attributes.Size();
604 }
605 
606 // GetAttributeValue
607 //
608 // Get the value of an attribute and return the .debug_info or .debug_types
609 // offset of the attribute if it was properly extracted into form_value,
610 // or zero if we fail since an offset of zero is invalid for an attribute (it
611 // would be a compile unit header).
612 dw_offset_t DWARFDebugInfoEntry::GetAttributeValue(
613     const DWARFUnit *cu, const dw_attr_t attr, DWARFFormValue &form_value,
614     dw_offset_t *end_attr_offset_ptr,
615     bool check_specification_or_abstract_origin) const {
616   SymbolFileDWARFDwo *dwo_symbol_file = cu->GetDwoSymbolFile();
617   if (dwo_symbol_file && m_tag != DW_TAG_compile_unit &&
618                          m_tag != DW_TAG_partial_unit)
619     return GetAttributeValue(dwo_symbol_file->GetCompileUnit(), attr,
620                              form_value, end_attr_offset_ptr,
621                              check_specification_or_abstract_origin);
622 
623   auto abbrevDecl = GetAbbreviationDeclarationPtr(cu);
624 
625   if (abbrevDecl) {
626     uint32_t attr_idx = abbrevDecl->FindAttributeIndex(attr);
627 
628     if (attr_idx != DW_INVALID_INDEX) {
629       const DWARFDataExtractor &data = cu->GetData();
630       lldb::offset_t offset = GetFirstAttributeOffset();
631 
632       uint32_t idx = 0;
633       while (idx < attr_idx)
634         DWARFFormValue::SkipValue(abbrevDecl->GetFormByIndex(idx++),
635                                   data, &offset, cu);
636 
637       const dw_offset_t attr_offset = offset;
638       form_value.SetUnit(cu);
639       form_value.SetForm(abbrevDecl->GetFormByIndex(idx));
640       if (form_value.ExtractValue(data, &offset)) {
641         if (end_attr_offset_ptr)
642           *end_attr_offset_ptr = offset;
643         return attr_offset;
644       }
645     }
646   }
647 
648   if (check_specification_or_abstract_origin) {
649     if (GetAttributeValue(cu, DW_AT_specification, form_value)) {
650       DWARFDIE die = form_value.Reference();
651       if (die) {
652         dw_offset_t die_offset = die.GetDIE()->GetAttributeValue(
653             die.GetCU(), attr, form_value, end_attr_offset_ptr, false);
654         if (die_offset)
655           return die_offset;
656       }
657     }
658 
659     if (GetAttributeValue(cu, DW_AT_abstract_origin, form_value)) {
660       DWARFDIE die = form_value.Reference();
661       if (die) {
662         dw_offset_t die_offset = die.GetDIE()->GetAttributeValue(
663             die.GetCU(), attr, form_value, end_attr_offset_ptr, false);
664         if (die_offset)
665           return die_offset;
666       }
667     }
668   }
669 
670   if (!dwo_symbol_file)
671     return 0;
672 
673   DWARFUnit *dwo_cu = dwo_symbol_file->GetCompileUnit();
674   if (!dwo_cu)
675     return 0;
676 
677   DWARFBaseDIE dwo_cu_die = dwo_cu->GetUnitDIEOnly();
678   if (!dwo_cu_die.IsValid())
679     return 0;
680 
681   return dwo_cu_die.GetDIE()->GetAttributeValue(
682       dwo_cu, attr, form_value, end_attr_offset_ptr,
683       check_specification_or_abstract_origin);
684 }
685 
686 // GetAttributeValueAsString
687 //
688 // Get the value of an attribute as a string return it. The resulting pointer
689 // to the string data exists within the supplied SymbolFileDWARF and will only
690 // be available as long as the SymbolFileDWARF is still around and it's content
691 // doesn't change.
692 const char *DWARFDebugInfoEntry::GetAttributeValueAsString(
693     const DWARFUnit *cu, const dw_attr_t attr, const char *fail_value,
694     bool check_specification_or_abstract_origin) const {
695   DWARFFormValue form_value;
696   if (GetAttributeValue(cu, attr, form_value, nullptr,
697                         check_specification_or_abstract_origin))
698     return form_value.AsCString();
699   return fail_value;
700 }
701 
702 // GetAttributeValueAsUnsigned
703 //
704 // Get the value of an attribute as unsigned and return it.
705 uint64_t DWARFDebugInfoEntry::GetAttributeValueAsUnsigned(
706     const DWARFUnit *cu, const dw_attr_t attr, uint64_t fail_value,
707     bool check_specification_or_abstract_origin) const {
708   DWARFFormValue form_value;
709   if (GetAttributeValue(cu, attr, form_value, nullptr,
710                         check_specification_or_abstract_origin))
711     return form_value.Unsigned();
712   return fail_value;
713 }
714 
715 // GetAttributeValueAsReference
716 //
717 // Get the value of an attribute as reference and fix up and compile unit
718 // relative offsets as needed.
719 DWARFDIE DWARFDebugInfoEntry::GetAttributeValueAsReference(
720     const DWARFUnit *cu, const dw_attr_t attr,
721     bool check_specification_or_abstract_origin) const {
722   DWARFFormValue form_value;
723   if (GetAttributeValue(cu, attr, form_value, nullptr,
724                         check_specification_or_abstract_origin))
725     return form_value.Reference();
726   return {};
727 }
728 
729 uint64_t DWARFDebugInfoEntry::GetAttributeValueAsAddress(
730     const DWARFUnit *cu, const dw_attr_t attr, uint64_t fail_value,
731     bool check_specification_or_abstract_origin) const {
732   DWARFFormValue form_value;
733   if (GetAttributeValue(cu, attr, form_value, nullptr,
734                         check_specification_or_abstract_origin))
735     return form_value.Address();
736   return fail_value;
737 }
738 
739 // GetAttributeHighPC
740 //
741 // Get the hi_pc, adding hi_pc to lo_pc when specified as an <offset-from-low-
742 // pc>.
743 //
744 // Returns the hi_pc or fail_value.
745 dw_addr_t DWARFDebugInfoEntry::GetAttributeHighPC(
746     const DWARFUnit *cu, dw_addr_t lo_pc, uint64_t fail_value,
747     bool check_specification_or_abstract_origin) const {
748   DWARFFormValue form_value;
749   if (GetAttributeValue(cu, DW_AT_high_pc, form_value, nullptr,
750                         check_specification_or_abstract_origin)) {
751     dw_form_t form = form_value.Form();
752     if (form == DW_FORM_addr || form == DW_FORM_addrx ||
753         form == DW_FORM_GNU_addr_index)
754       return form_value.Address();
755 
756     // DWARF4 can specify the hi_pc as an <offset-from-lowpc>
757     return lo_pc + form_value.Unsigned();
758   }
759   return fail_value;
760 }
761 
762 // GetAttributeAddressRange
763 //
764 // Get the lo_pc and hi_pc, adding hi_pc to lo_pc when specified as an <offset-
765 // from-low-pc>.
766 //
767 // Returns true or sets lo_pc and hi_pc to fail_value.
768 bool DWARFDebugInfoEntry::GetAttributeAddressRange(
769     const DWARFUnit *cu, dw_addr_t &lo_pc, dw_addr_t &hi_pc,
770     uint64_t fail_value, bool check_specification_or_abstract_origin) const {
771   lo_pc = GetAttributeValueAsAddress(cu, DW_AT_low_pc, fail_value,
772                                      check_specification_or_abstract_origin);
773   if (lo_pc != fail_value) {
774     hi_pc = GetAttributeHighPC(cu, lo_pc, fail_value,
775                                check_specification_or_abstract_origin);
776     if (hi_pc != fail_value)
777       return true;
778   }
779   lo_pc = fail_value;
780   hi_pc = fail_value;
781   return false;
782 }
783 
784 size_t DWARFDebugInfoEntry::GetAttributeAddressRanges(
785     const DWARFUnit *cu, DWARFRangeList &ranges, bool check_hi_lo_pc,
786     bool check_specification_or_abstract_origin) const {
787   ranges.Clear();
788 
789   DWARFFormValue form_value;
790   if (GetAttributeValue(cu, DW_AT_ranges, form_value)) {
791     ranges = GetRangesOrReportError(*cu, *this, form_value);
792   } else if (check_hi_lo_pc) {
793     dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
794     dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
795     if (GetAttributeAddressRange(cu, lo_pc, hi_pc, LLDB_INVALID_ADDRESS,
796                                  check_specification_or_abstract_origin)) {
797       if (lo_pc < hi_pc)
798         ranges.Append(DWARFRangeList::Entry(lo_pc, hi_pc - lo_pc));
799     }
800   }
801   return ranges.GetSize();
802 }
803 
804 // GetName
805 //
806 // Get value of the DW_AT_name attribute and return it if one exists, else
807 // return NULL.
808 const char *DWARFDebugInfoEntry::GetName(const DWARFUnit *cu) const {
809   return GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
810 }
811 
812 // GetMangledName
813 //
814 // Get value of the DW_AT_MIPS_linkage_name attribute and return it if one
815 // exists, else return the value of the DW_AT_name attribute
816 const char *
817 DWARFDebugInfoEntry::GetMangledName(const DWARFUnit *cu,
818                                     bool substitute_name_allowed) const {
819   const char *name = nullptr;
820 
821   name = GetAttributeValueAsString(cu, DW_AT_MIPS_linkage_name, nullptr, true);
822   if (name)
823     return name;
824 
825   name = GetAttributeValueAsString(cu, DW_AT_linkage_name, nullptr, true);
826   if (name)
827     return name;
828 
829   if (!substitute_name_allowed)
830     return nullptr;
831 
832   name = GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
833   return name;
834 }
835 
836 // GetPubname
837 //
838 // Get value the name for a DIE as it should appear for a .debug_pubnames or
839 // .debug_pubtypes section.
840 const char *DWARFDebugInfoEntry::GetPubname(const DWARFUnit *cu) const {
841   const char *name = nullptr;
842   if (!cu)
843     return name;
844 
845   name = GetAttributeValueAsString(cu, DW_AT_MIPS_linkage_name, nullptr, true);
846   if (name)
847     return name;
848 
849   name = GetAttributeValueAsString(cu, DW_AT_linkage_name, nullptr, true);
850   if (name)
851     return name;
852 
853   name = GetAttributeValueAsString(cu, DW_AT_name, nullptr, true);
854   return name;
855 }
856 
857 // BuildAddressRangeTable
858 void DWARFDebugInfoEntry::BuildAddressRangeTable(
859     const DWARFUnit *cu, DWARFDebugAranges *debug_aranges) const {
860   if (m_tag) {
861     if (m_tag == DW_TAG_subprogram) {
862       dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
863       dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
864       if (GetAttributeAddressRange(cu, lo_pc, hi_pc, LLDB_INVALID_ADDRESS)) {
865         /// printf("BuildAddressRangeTable() 0x%8.8x: %30s: [0x%8.8x -
866         /// 0x%8.8x)\n", m_offset, DW_TAG_value_to_name(tag), lo_pc, hi_pc);
867         debug_aranges->AppendRange(cu->GetOffset(), lo_pc, hi_pc);
868       }
869     }
870 
871     const DWARFDebugInfoEntry *child = GetFirstChild();
872     while (child) {
873       child->BuildAddressRangeTable(cu, debug_aranges);
874       child = child->GetSibling();
875     }
876   }
877 }
878 
879 // BuildFunctionAddressRangeTable
880 //
881 // This function is very similar to the BuildAddressRangeTable function except
882 // that the actual DIE offset for the function is placed in the table instead
883 // of the compile unit offset (which is the way the standard .debug_aranges
884 // section does it).
885 void DWARFDebugInfoEntry::BuildFunctionAddressRangeTable(
886     const DWARFUnit *cu, DWARFDebugAranges *debug_aranges) const {
887   if (m_tag) {
888     if (m_tag == DW_TAG_subprogram) {
889       dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
890       dw_addr_t hi_pc = LLDB_INVALID_ADDRESS;
891       if (GetAttributeAddressRange(cu, lo_pc, hi_pc, LLDB_INVALID_ADDRESS)) {
892         //  printf("BuildAddressRangeTable() 0x%8.8x: [0x%16.16" PRIx64 " -
893         //  0x%16.16" PRIx64 ")\n", m_offset, lo_pc, hi_pc); // DEBUG ONLY
894         debug_aranges->AppendRange(GetOffset(), lo_pc, hi_pc);
895       }
896     }
897 
898     const DWARFDebugInfoEntry *child = GetFirstChild();
899     while (child) {
900       child->BuildFunctionAddressRangeTable(cu, debug_aranges);
901       child = child->GetSibling();
902     }
903   }
904 }
905 
906 void DWARFDebugInfoEntry::GetDWARFDeclContext(
907     DWARFUnit *cu, DWARFDeclContext &dwarf_decl_ctx) const {
908   const dw_tag_t tag = Tag();
909   if (tag != DW_TAG_compile_unit && tag != DW_TAG_partial_unit) {
910     dwarf_decl_ctx.AppendDeclContext(tag, GetName(cu));
911     DWARFDIE parent_decl_ctx_die = GetParentDeclContextDIE(cu);
912     if (parent_decl_ctx_die && parent_decl_ctx_die.GetDIE() != this) {
913       if (parent_decl_ctx_die.Tag() != DW_TAG_compile_unit &&
914           parent_decl_ctx_die.Tag() != DW_TAG_partial_unit)
915         parent_decl_ctx_die.GetDIE()->GetDWARFDeclContext(
916             parent_decl_ctx_die.GetCU(), dwarf_decl_ctx);
917     }
918   }
919 }
920 
921 DWARFDIE
922 DWARFDebugInfoEntry::GetParentDeclContextDIE(DWARFUnit *cu) const {
923   DWARFAttributes attributes;
924   GetAttributes(cu, attributes);
925   return GetParentDeclContextDIE(cu, attributes);
926 }
927 
928 DWARFDIE
929 DWARFDebugInfoEntry::GetParentDeclContextDIE(
930     DWARFUnit *cu, const DWARFAttributes &attributes) const {
931   DWARFDIE die(cu, const_cast<DWARFDebugInfoEntry *>(this));
932 
933   while (die) {
934     // If this is the original DIE that we are searching for a declaration for,
935     // then don't look in the cache as we don't want our own decl context to be
936     // our decl context...
937     if (die.GetDIE() != this) {
938       switch (die.Tag()) {
939       case DW_TAG_compile_unit:
940       case DW_TAG_partial_unit:
941       case DW_TAG_namespace:
942       case DW_TAG_structure_type:
943       case DW_TAG_union_type:
944       case DW_TAG_class_type:
945         return die;
946 
947       default:
948         break;
949       }
950     }
951 
952     DWARFDIE spec_die = attributes.FormValueAsReference(DW_AT_specification);
953     if (spec_die) {
954       DWARFDIE decl_ctx_die = spec_die.GetParentDeclContextDIE();
955       if (decl_ctx_die)
956         return decl_ctx_die;
957     }
958 
959     DWARFDIE abs_die = attributes.FormValueAsReference(DW_AT_abstract_origin);
960     if (abs_die) {
961       DWARFDIE decl_ctx_die = abs_die.GetParentDeclContextDIE();
962       if (decl_ctx_die)
963         return decl_ctx_die;
964     }
965 
966     die = die.GetParent();
967   }
968   return DWARFDIE();
969 }
970 
971 const char *DWARFDebugInfoEntry::GetQualifiedName(DWARFUnit *cu,
972                                                   std::string &storage) const {
973   DWARFAttributes attributes;
974   GetAttributes(cu, attributes);
975   return GetQualifiedName(cu, attributes, storage);
976 }
977 
978 const char *
979 DWARFDebugInfoEntry::GetQualifiedName(DWARFUnit *cu,
980                                       const DWARFAttributes &attributes,
981                                       std::string &storage) const {
982 
983   const char *name = GetName(cu);
984 
985   if (name) {
986     DWARFDIE parent_decl_ctx_die = GetParentDeclContextDIE(cu);
987     storage.clear();
988     // TODO: change this to get the correct decl context parent....
989     while (parent_decl_ctx_die) {
990       const dw_tag_t parent_tag = parent_decl_ctx_die.Tag();
991       switch (parent_tag) {
992       case DW_TAG_namespace: {
993         const char *namespace_name = parent_decl_ctx_die.GetName();
994         if (namespace_name) {
995           storage.insert(0, "::");
996           storage.insert(0, namespace_name);
997         } else {
998           storage.insert(0, "(anonymous namespace)::");
999         }
1000         parent_decl_ctx_die = parent_decl_ctx_die.GetParentDeclContextDIE();
1001       } break;
1002 
1003       case DW_TAG_class_type:
1004       case DW_TAG_structure_type:
1005       case DW_TAG_union_type: {
1006         const char *class_union_struct_name = parent_decl_ctx_die.GetName();
1007 
1008         if (class_union_struct_name) {
1009           storage.insert(0, "::");
1010           storage.insert(0, class_union_struct_name);
1011         }
1012         parent_decl_ctx_die = parent_decl_ctx_die.GetParentDeclContextDIE();
1013       } break;
1014 
1015       default:
1016         parent_decl_ctx_die.Clear();
1017         break;
1018       }
1019     }
1020 
1021     if (storage.empty())
1022       storage.append("::");
1023 
1024     storage.append(name);
1025   }
1026   if (storage.empty())
1027     return nullptr;
1028   return storage.c_str();
1029 }
1030 
1031 bool DWARFDebugInfoEntry::LookupAddress(const dw_addr_t address,
1032                                         const DWARFUnit *cu,
1033                                         DWARFDebugInfoEntry **function_die,
1034                                         DWARFDebugInfoEntry **block_die) {
1035   bool found_address = false;
1036   if (m_tag) {
1037     bool check_children = false;
1038     bool match_addr_range = false;
1039     //  printf("0x%8.8x: %30s: address = 0x%8.8x - ", m_offset,
1040     //  DW_TAG_value_to_name(tag), address);
1041     switch (m_tag) {
1042     case DW_TAG_array_type:
1043       break;
1044     case DW_TAG_class_type:
1045       check_children = true;
1046       break;
1047     case DW_TAG_entry_point:
1048     case DW_TAG_enumeration_type:
1049     case DW_TAG_formal_parameter:
1050     case DW_TAG_imported_declaration:
1051     case DW_TAG_label:
1052       break;
1053     case DW_TAG_lexical_block:
1054       check_children = true;
1055       match_addr_range = true;
1056       break;
1057     case DW_TAG_member:
1058     case DW_TAG_pointer_type:
1059     case DW_TAG_reference_type:
1060       break;
1061     case DW_TAG_compile_unit:
1062       match_addr_range = true;
1063       break;
1064     case DW_TAG_string_type:
1065       break;
1066     case DW_TAG_structure_type:
1067       check_children = true;
1068       break;
1069     case DW_TAG_subroutine_type:
1070     case DW_TAG_typedef:
1071     case DW_TAG_union_type:
1072     case DW_TAG_unspecified_parameters:
1073     case DW_TAG_variant:
1074       break;
1075     case DW_TAG_common_block:
1076       check_children = true;
1077       break;
1078     case DW_TAG_common_inclusion:
1079     case DW_TAG_inheritance:
1080       break;
1081     case DW_TAG_inlined_subroutine:
1082       check_children = true;
1083       match_addr_range = true;
1084       break;
1085     case DW_TAG_module:
1086       match_addr_range = true;
1087       break;
1088     case DW_TAG_ptr_to_member_type:
1089     case DW_TAG_set_type:
1090     case DW_TAG_subrange_type:
1091     case DW_TAG_with_stmt:
1092     case DW_TAG_access_declaration:
1093     case DW_TAG_base_type:
1094       break;
1095     case DW_TAG_catch_block:
1096       match_addr_range = true;
1097       break;
1098     case DW_TAG_const_type:
1099     case DW_TAG_constant:
1100     case DW_TAG_enumerator:
1101     case DW_TAG_file_type:
1102     case DW_TAG_friend:
1103     case DW_TAG_namelist:
1104     case DW_TAG_namelist_item:
1105     case DW_TAG_packed_type:
1106       break;
1107     case DW_TAG_subprogram:
1108       match_addr_range = true;
1109       break;
1110     case DW_TAG_template_type_parameter:
1111     case DW_TAG_template_value_parameter:
1112     case DW_TAG_GNU_template_parameter_pack:
1113     case DW_TAG_thrown_type:
1114       break;
1115     case DW_TAG_try_block:
1116       match_addr_range = true;
1117       break;
1118     case DW_TAG_variant_part:
1119     case DW_TAG_variable:
1120     case DW_TAG_volatile_type:
1121     case DW_TAG_dwarf_procedure:
1122     case DW_TAG_restrict_type:
1123     case DW_TAG_interface_type:
1124       break;
1125     case DW_TAG_namespace:
1126       check_children = true;
1127       break;
1128     case DW_TAG_imported_module:
1129     case DW_TAG_unspecified_type:
1130       break;
1131     case DW_TAG_partial_unit:
1132       match_addr_range = true;
1133       break;
1134     case DW_TAG_imported_unit:
1135     case DW_TAG_shared_type:
1136     default:
1137       break;
1138     }
1139 
1140     if (match_addr_range) {
1141       dw_addr_t lo_pc =
1142           GetAttributeValueAsAddress(cu, DW_AT_low_pc, LLDB_INVALID_ADDRESS);
1143       if (lo_pc != LLDB_INVALID_ADDRESS) {
1144         dw_addr_t hi_pc = GetAttributeHighPC(cu, lo_pc, LLDB_INVALID_ADDRESS);
1145         if (hi_pc != LLDB_INVALID_ADDRESS) {
1146           //  printf("\n0x%8.8x: %30s: address = 0x%8.8x  [0x%8.8x - 0x%8.8x) ",
1147           //  m_offset, DW_TAG_value_to_name(tag), address, lo_pc, hi_pc);
1148           if ((lo_pc <= address) && (address < hi_pc)) {
1149             found_address = true;
1150             //  puts("***MATCH***");
1151             switch (m_tag) {
1152             case DW_TAG_compile_unit: // File
1153             case DW_TAG_partial_unit: // File
1154               check_children =
1155                   ((function_die != nullptr) || (block_die != nullptr));
1156               break;
1157 
1158             case DW_TAG_subprogram: // Function
1159               if (function_die)
1160                 *function_die = this;
1161               check_children = (block_die != nullptr);
1162               break;
1163 
1164             case DW_TAG_inlined_subroutine: // Inlined Function
1165             case DW_TAG_lexical_block:      // Block { } in code
1166               if (block_die) {
1167                 *block_die = this;
1168                 check_children = true;
1169               }
1170               break;
1171 
1172             default:
1173               check_children = true;
1174               break;
1175             }
1176           }
1177         } else {
1178           // Compile units may not have a valid high/low pc when there
1179           // are address gaps in subroutines so we must always search
1180           // if there is no valid high and low PC.
1181           check_children =
1182               (m_tag == DW_TAG_compile_unit || m_tag == DW_TAG_partial_unit) &&
1183               ((function_die != nullptr) || (block_die != nullptr));
1184         }
1185       } else {
1186         DWARFRangeList ranges;
1187         if (GetAttributeAddressRanges(cu, ranges, /*check_hi_lo_pc*/ false) &&
1188             ranges.FindEntryThatContains(address)) {
1189           found_address = true;
1190           //  puts("***MATCH***");
1191           switch (m_tag) {
1192           case DW_TAG_compile_unit: // File
1193           case DW_TAG_partial_unit: // File
1194               check_children =
1195                   ((function_die != nullptr) || (block_die != nullptr));
1196               break;
1197 
1198           case DW_TAG_subprogram: // Function
1199             if (function_die)
1200               *function_die = this;
1201             check_children = (block_die != nullptr);
1202             break;
1203 
1204           case DW_TAG_inlined_subroutine: // Inlined Function
1205           case DW_TAG_lexical_block:      // Block { } in code
1206             if (block_die) {
1207               *block_die = this;
1208               check_children = true;
1209             }
1210             break;
1211 
1212           default:
1213             check_children = true;
1214             break;
1215           }
1216         } else {
1217           check_children = false;
1218         }
1219       }
1220     }
1221 
1222     if (check_children) {
1223       //  printf("checking children\n");
1224       DWARFDebugInfoEntry *child = GetFirstChild();
1225       while (child) {
1226         if (child->LookupAddress(address, cu, function_die, block_die))
1227           return true;
1228         child = child->GetSibling();
1229       }
1230     }
1231   }
1232   return found_address;
1233 }
1234 
1235 lldb::offset_t DWARFDebugInfoEntry::GetFirstAttributeOffset() const {
1236   return GetOffset() + llvm::getULEB128Size(m_abbr_idx);
1237 }
1238 
1239 const DWARFAbbreviationDeclaration *
1240 DWARFDebugInfoEntry::GetAbbreviationDeclarationPtr(const DWARFUnit *cu) const {
1241   if (cu) {
1242     const DWARFAbbreviationDeclarationSet *abbrev_set = cu->GetAbbreviations();
1243     if (abbrev_set)
1244       return abbrev_set->GetAbbreviationDeclaration(m_abbr_idx);
1245   }
1246   return nullptr;
1247 }
1248 
1249 bool DWARFDebugInfoEntry::operator==(const DWARFDebugInfoEntry &rhs) const {
1250   return m_offset == rhs.m_offset && m_parent_idx == rhs.m_parent_idx &&
1251          m_sibling_idx == rhs.m_sibling_idx &&
1252          m_abbr_idx == rhs.m_abbr_idx && m_has_children == rhs.m_has_children &&
1253          m_tag == rhs.m_tag;
1254 }
1255 
1256 bool DWARFDebugInfoEntry::operator!=(const DWARFDebugInfoEntry &rhs) const {
1257   return !(*this == rhs);
1258 }
1259