1 //===-- DWARFDIE.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 "DWARFDIE.h"
10 
11 #include "DWARFASTParser.h"
12 #include "DWARFDebugInfo.h"
13 #include "DWARFDebugInfoEntry.h"
14 #include "DWARFDeclContext.h"
15 #include "DWARFUnit.h"
16 
17 using namespace lldb_private;
18 
19 namespace {
20 
21 /// Iterate through all DIEs elaborating (i.e. reachable by a chain of
22 /// DW_AT_specification and DW_AT_abstract_origin attributes) a given DIE. For
23 /// convenience, the starting die is included in the sequence as the first
24 /// item.
25 class ElaboratingDIEIterator
26     : public std::iterator<std::input_iterator_tag, DWARFDIE> {
27 
28   // The operating invariant is: top of m_worklist contains the "current" item
29   // and the rest of the list are items yet to be visited. An empty worklist
30   // means we've reached the end.
31   // Infinite recursion is prevented by maintaining a list of seen DIEs.
32   // Container sizes are optimized for the case of following DW_AT_specification
33   // and DW_AT_abstract_origin just once.
34   llvm::SmallVector<DWARFDIE, 2> m_worklist;
35   llvm::SmallSet<DWARFDebugInfoEntry *, 3> m_seen;
36 
37   void Next() {
38     assert(!m_worklist.empty() && "Incrementing end iterator?");
39 
40     // Pop the current item from the list.
41     DWARFDIE die = m_worklist.back();
42     m_worklist.pop_back();
43 
44     // And add back any items that elaborate it.
45     for (dw_attr_t attr : {DW_AT_specification, DW_AT_abstract_origin}) {
46       if (DWARFDIE d = die.GetReferencedDIE(attr))
47         if (m_seen.insert(die.GetDIE()).second)
48           m_worklist.push_back(d);
49     }
50   }
51 
52 public:
53   /// An iterator starting at die d.
54   explicit ElaboratingDIEIterator(DWARFDIE d) : m_worklist(1, d) {}
55 
56   /// End marker
57   ElaboratingDIEIterator() = default;
58 
59   const DWARFDIE &operator*() const { return m_worklist.back(); }
60   ElaboratingDIEIterator &operator++() {
61     Next();
62     return *this;
63   }
64   ElaboratingDIEIterator operator++(int) {
65     ElaboratingDIEIterator I = *this;
66     Next();
67     return I;
68   }
69 
70   friend bool operator==(const ElaboratingDIEIterator &a,
71                          const ElaboratingDIEIterator &b) {
72     if (a.m_worklist.empty() || b.m_worklist.empty())
73       return a.m_worklist.empty() == b.m_worklist.empty();
74     return a.m_worklist.back() == b.m_worklist.back();
75   }
76   friend bool operator!=(const ElaboratingDIEIterator &a,
77                          const ElaboratingDIEIterator &b) {
78     return !(a == b);
79   }
80 };
81 
82 llvm::iterator_range<ElaboratingDIEIterator>
83 elaborating_dies(const DWARFDIE &die) {
84   return llvm::make_range(ElaboratingDIEIterator(die),
85                           ElaboratingDIEIterator());
86 }
87 } // namespace
88 
89 DWARFDIE
90 DWARFDIE::GetParent() const {
91   if (IsValid())
92     return DWARFDIE(m_cu, m_die->GetParent());
93   else
94     return DWARFDIE();
95 }
96 
97 DWARFDIE
98 DWARFDIE::GetFirstChild() const {
99   if (IsValid())
100     return DWARFDIE(m_cu, m_die->GetFirstChild());
101   else
102     return DWARFDIE();
103 }
104 
105 DWARFDIE
106 DWARFDIE::GetSibling() const {
107   if (IsValid())
108     return DWARFDIE(m_cu, m_die->GetSibling());
109   else
110     return DWARFDIE();
111 }
112 
113 DWARFDIE
114 DWARFDIE::GetReferencedDIE(const dw_attr_t attr) const {
115   if (IsValid())
116     return m_die->GetAttributeValueAsReference(GetCU(), attr);
117   else
118     return {};
119 }
120 
121 DWARFDIE
122 DWARFDIE::GetDIE(dw_offset_t die_offset) const {
123   if (IsValid())
124     return m_cu->GetDIE(die_offset);
125   else
126     return DWARFDIE();
127 }
128 
129 DWARFDIE
130 DWARFDIE::GetAttributeValueAsReferenceDIE(const dw_attr_t attr) const {
131   if (IsValid()) {
132     DWARFUnit *cu = GetCU();
133     const bool check_specification_or_abstract_origin = true;
134     DWARFFormValue form_value;
135     if (m_die->GetAttributeValue(cu, attr, form_value, nullptr,
136                                  check_specification_or_abstract_origin))
137       return form_value.Reference();
138   }
139   return DWARFDIE();
140 }
141 
142 DWARFDIE
143 DWARFDIE::LookupDeepestBlock(lldb::addr_t address) const {
144   if (!IsValid())
145     return DWARFDIE();
146 
147   DWARFDIE result;
148   bool check_children = false;
149   bool match_addr_range = false;
150   switch (Tag()) {
151   case DW_TAG_class_type:
152   case DW_TAG_namespace:
153   case DW_TAG_structure_type:
154   case DW_TAG_common_block:
155     check_children = true;
156     break;
157   case DW_TAG_compile_unit:
158   case DW_TAG_module:
159   case DW_TAG_catch_block:
160   case DW_TAG_subprogram:
161   case DW_TAG_try_block:
162   case DW_TAG_partial_unit:
163     match_addr_range = true;
164     break;
165   case DW_TAG_lexical_block:
166   case DW_TAG_inlined_subroutine:
167     check_children = true;
168     match_addr_range = true;
169     break;
170   default:
171     break;
172   }
173 
174   if (match_addr_range) {
175     DWARFRangeList ranges;
176     if (m_die->GetAttributeAddressRanges(m_cu, ranges,
177                                          /*check_hi_lo_pc=*/true) &&
178         ranges.FindEntryThatContains(address)) {
179       check_children = true;
180       switch (Tag()) {
181       default:
182         break;
183 
184       case DW_TAG_inlined_subroutine: // Inlined Function
185       case DW_TAG_lexical_block:      // Block { } in code
186         result = *this;
187         break;
188       }
189     } else {
190       check_children = false;
191     }
192   }
193 
194   if (check_children) {
195     for (DWARFDIE child : children()) {
196       if (DWARFDIE child_result = child.LookupDeepestBlock(address))
197         return child_result;
198     }
199   }
200   return result;
201 }
202 
203 const char *DWARFDIE::GetMangledName() const {
204   if (IsValid())
205     return m_die->GetMangledName(m_cu);
206   else
207     return nullptr;
208 }
209 
210 const char *DWARFDIE::GetPubname() const {
211   if (IsValid())
212     return m_die->GetPubname(m_cu);
213   else
214     return nullptr;
215 }
216 
217 const char *DWARFDIE::GetQualifiedName(std::string &storage) const {
218   if (IsValid())
219     return m_die->GetQualifiedName(m_cu, storage);
220   else
221     return nullptr;
222 }
223 
224 // GetName
225 //
226 // Get value of the DW_AT_name attribute and place that value into the supplied
227 // stream object. If the DIE is a NULL object "NULL" is placed into the stream,
228 // and if no DW_AT_name attribute exists for the DIE then nothing is printed.
229 void DWARFDIE::GetName(Stream &s) const {
230   if (!IsValid())
231     return;
232   if (GetDIE()->IsNULL()) {
233     s.PutCString("NULL");
234     return;
235   }
236   const char *name = GetDIE()->GetAttributeValueAsString(GetCU(), DW_AT_name, nullptr, true);
237   if (!name)
238     return;
239   s.PutCString(name);
240 }
241 
242 // AppendTypeName
243 //
244 // Follows the type name definition down through all needed tags to end up with
245 // a fully qualified type name and dump the results to the supplied stream.
246 // This is used to show the name of types given a type identifier.
247 void DWARFDIE::AppendTypeName(Stream &s) const {
248   if (!IsValid())
249     return;
250   if (GetDIE()->IsNULL()) {
251     s.PutCString("NULL");
252     return;
253   }
254   if (const char *name = GetPubname()) {
255     s.PutCString(name);
256     return;
257   }
258   switch (Tag()) {
259   case DW_TAG_array_type:
260     break; // print out a "[]" after printing the full type of the element
261            // below
262   case DW_TAG_base_type:
263     s.PutCString("base ");
264     break;
265   case DW_TAG_class_type:
266     s.PutCString("class ");
267     break;
268   case DW_TAG_const_type:
269     s.PutCString("const ");
270     break;
271   case DW_TAG_enumeration_type:
272     s.PutCString("enum ");
273     break;
274   case DW_TAG_file_type:
275     s.PutCString("file ");
276     break;
277   case DW_TAG_interface_type:
278     s.PutCString("interface ");
279     break;
280   case DW_TAG_packed_type:
281     s.PutCString("packed ");
282     break;
283   case DW_TAG_pointer_type:
284     break; // print out a '*' after printing the full type below
285   case DW_TAG_ptr_to_member_type:
286     break; // print out a '*' after printing the full type below
287   case DW_TAG_reference_type:
288     break; // print out a '&' after printing the full type below
289   case DW_TAG_restrict_type:
290     s.PutCString("restrict ");
291     break;
292   case DW_TAG_set_type:
293     s.PutCString("set ");
294     break;
295   case DW_TAG_shared_type:
296     s.PutCString("shared ");
297     break;
298   case DW_TAG_string_type:
299     s.PutCString("string ");
300     break;
301   case DW_TAG_structure_type:
302     s.PutCString("struct ");
303     break;
304   case DW_TAG_subrange_type:
305     s.PutCString("subrange ");
306     break;
307   case DW_TAG_subroutine_type:
308     s.PutCString("function ");
309     break;
310   case DW_TAG_thrown_type:
311     s.PutCString("thrown ");
312     break;
313   case DW_TAG_union_type:
314     s.PutCString("union ");
315     break;
316   case DW_TAG_unspecified_type:
317     s.PutCString("unspecified ");
318     break;
319   case DW_TAG_volatile_type:
320     s.PutCString("volatile ");
321     break;
322   default:
323     return;
324   }
325 
326   // Follow the DW_AT_type if possible
327   if (DWARFDIE next_die = GetAttributeValueAsReferenceDIE(DW_AT_type))
328     next_die.AppendTypeName(s);
329 
330   switch (Tag()) {
331   case DW_TAG_array_type:
332     s.PutCString("[]");
333     break;
334   case DW_TAG_pointer_type:
335     s.PutChar('*');
336     break;
337   case DW_TAG_ptr_to_member_type:
338     s.PutChar('*');
339     break;
340   case DW_TAG_reference_type:
341     s.PutChar('&');
342     break;
343   default:
344     break;
345   }
346 }
347 
348 lldb_private::Type *DWARFDIE::ResolveType() const {
349   if (IsValid())
350     return GetDWARF()->ResolveType(*this, true);
351   else
352     return nullptr;
353 }
354 
355 lldb_private::Type *DWARFDIE::ResolveTypeUID(const DWARFDIE &die) const {
356   if (SymbolFileDWARF *dwarf = GetDWARF())
357     return dwarf->ResolveTypeUID(die, true);
358   return nullptr;
359 }
360 
361 std::vector<DWARFDIE> DWARFDIE::GetDeclContextDIEs() const {
362   if (!IsValid())
363     return {};
364 
365   std::vector<DWARFDIE> result;
366   DWARFDIE parent = GetParentDeclContextDIE();
367   while (parent.IsValid() && parent.GetDIE() != GetDIE()) {
368     result.push_back(std::move(parent));
369     parent = parent.GetParentDeclContextDIE();
370   }
371 
372   return result;
373 }
374 
375 void DWARFDIE::GetDeclContext(
376     llvm::SmallVectorImpl<lldb_private::CompilerContext> &context) const {
377   const dw_tag_t tag = Tag();
378   if (tag == DW_TAG_compile_unit || tag == DW_TAG_partial_unit)
379     return;
380   DWARFDIE parent = GetParent();
381   if (parent)
382     parent.GetDeclContext(context);
383   switch (tag) {
384   case DW_TAG_module:
385     context.push_back({CompilerContextKind::Module, ConstString(GetName())});
386     break;
387   case DW_TAG_namespace:
388     context.push_back({CompilerContextKind::Namespace, ConstString(GetName())});
389     break;
390   case DW_TAG_structure_type:
391     context.push_back({CompilerContextKind::Struct, ConstString(GetName())});
392     break;
393   case DW_TAG_union_type:
394     context.push_back({CompilerContextKind::Union, ConstString(GetName())});
395     break;
396   case DW_TAG_class_type:
397     context.push_back({CompilerContextKind::Class, ConstString(GetName())});
398     break;
399   case DW_TAG_enumeration_type:
400     context.push_back({CompilerContextKind::Enum, ConstString(GetName())});
401     break;
402   case DW_TAG_subprogram:
403     context.push_back(
404         {CompilerContextKind::Function, ConstString(GetPubname())});
405     break;
406   case DW_TAG_variable:
407     context.push_back(
408         {CompilerContextKind::Variable, ConstString(GetPubname())});
409     break;
410   case DW_TAG_typedef:
411     context.push_back({CompilerContextKind::Typedef, ConstString(GetName())});
412     break;
413   default:
414     break;
415   }
416 }
417 
418 DWARFDIE
419 DWARFDIE::GetParentDeclContextDIE() const {
420   if (IsValid())
421     return m_die->GetParentDeclContextDIE(m_cu);
422   else
423     return DWARFDIE();
424 }
425 
426 bool DWARFDIE::IsStructUnionOrClass() const {
427   const dw_tag_t tag = Tag();
428   return tag == DW_TAG_class_type || tag == DW_TAG_structure_type ||
429          tag == DW_TAG_union_type;
430 }
431 
432 bool DWARFDIE::IsMethod() const {
433   for (DWARFDIE d : elaborating_dies(*this))
434     if (d.GetParent().IsStructUnionOrClass())
435       return true;
436   return false;
437 }
438 
439 bool DWARFDIE::GetDIENamesAndRanges(
440     const char *&name, const char *&mangled, DWARFRangeList &ranges,
441     int &decl_file, int &decl_line, int &decl_column, int &call_file,
442     int &call_line, int &call_column,
443     lldb_private::DWARFExpression *frame_base) const {
444   if (IsValid()) {
445     return m_die->GetDIENamesAndRanges(
446         GetCU(), name, mangled, ranges, decl_file, decl_line, decl_column,
447         call_file, call_line, call_column, frame_base);
448   } else
449     return false;
450 }
451