1 //===- DWARFDie.cpp -------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
11 #include "SyntaxHighlighting.h"
12 #include "llvm/ADT/None.h"
13 #include "llvm/ADT/Optional.h"
14 #include "llvm/ADT/StringRef.h"
15 #include "llvm/BinaryFormat/Dwarf.h"
16 #include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
17 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
18 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
19 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
20 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
21 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
22 #include "llvm/Object/ObjectFile.h"
23 #include "llvm/Support/DataExtractor.h"
24 #include "llvm/Support/Format.h"
25 #include "llvm/Support/MathExtras.h"
26 #include "llvm/Support/raw_ostream.h"
27 #include <algorithm>
28 #include <cassert>
29 #include <cinttypes>
30 #include <cstdint>
31 #include <string>
32 #include <utility>
33 
34 using namespace llvm;
35 using namespace dwarf;
36 using namespace object;
37 using namespace syntax;
38 
39 static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
40   OS << " (";
41   do {
42     uint64_t Shift = countTrailingZeros(Val);
43     assert(Shift < 64 && "undefined behavior");
44     uint64_t Bit = 1ULL << Shift;
45     auto PropName = ApplePropertyString(Bit);
46     if (!PropName.empty())
47       OS << PropName;
48     else
49       OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
50     if (!(Val ^= Bit))
51       break;
52     OS << ", ";
53   } while (true);
54   OS << ")";
55 }
56 
57 static void dumpRanges(const DWARFObject &Obj, raw_ostream &OS,
58                        const DWARFAddressRangesVector &Ranges,
59                        unsigned AddressSize, unsigned Indent,
60                        const DIDumpOptions &DumpOpts) {
61   ArrayRef<SectionName> SectionNames;
62   if (DumpOpts.Verbose)
63     SectionNames = Obj.getSectionNames();
64 
65   for (const DWARFAddressRange &R : Ranges) {
66 
67     OS << '\n';
68     OS.indent(Indent);
69     R.dump(OS, AddressSize);
70 
71     if (SectionNames.empty() || R.SectionIndex == -1ULL)
72       continue;
73 
74     StringRef Name = SectionNames[R.SectionIndex].Name;
75     OS << " \"" << Name << '\"';
76 
77     // Print section index if name is not unique.
78     if (!SectionNames[R.SectionIndex].IsNameUnique)
79       OS << format(" [%" PRIu64 "]", R.SectionIndex);
80   }
81 }
82 
83 static void dumpLocation(raw_ostream &OS, DWARFFormValue &FormValue,
84                          DWARFUnit *U, unsigned Indent,
85                          DIDumpOptions DumpOpts) {
86   DWARFContext &Ctx = U->getContext();
87   const DWARFObject &Obj = Ctx.getDWARFObj();
88   const MCRegisterInfo *MRI = Ctx.getRegisterInfo();
89   if (FormValue.isFormClass(DWARFFormValue::FC_Block) ||
90       FormValue.isFormClass(DWARFFormValue::FC_Exprloc)) {
91     ArrayRef<uint8_t> Expr = *FormValue.getAsBlock();
92     DataExtractor Data(StringRef((const char *)Expr.data(), Expr.size()),
93                        Ctx.isLittleEndian(), 0);
94     DWARFExpression(Data, U->getVersion(), U->getAddressByteSize())
95         .print(OS, MRI);
96     return;
97   }
98 
99   FormValue.dump(OS, DumpOpts);
100   if (FormValue.isFormClass(DWARFFormValue::FC_SectionOffset)) {
101     const DWARFSection &LocSection = Obj.getLocSection();
102     const DWARFSection &LocDWOSection = Obj.getLocDWOSection();
103     uint32_t Offset = *FormValue.getAsSectionOffset();
104 
105     if (!LocSection.Data.empty()) {
106       DWARFDebugLoc DebugLoc;
107       DWARFDataExtractor Data(Obj, LocSection, Ctx.isLittleEndian(),
108                               Obj.getAddressSize());
109       auto LL = DebugLoc.parseOneLocationList(Data, &Offset);
110       if (LL)
111         LL->dump(OS, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI, Indent);
112       else
113         OS << "error extracting location list.";
114     } else if (!LocDWOSection.Data.empty()) {
115       DataExtractor Data(LocDWOSection.Data, Ctx.isLittleEndian(), 0);
116       auto LL = DWARFDebugLocDWO::parseOneLocationList(Data, &Offset);
117       if (LL)
118         LL->dump(OS, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI, Indent);
119       else
120         OS << "error extracting location list.";
121     }
122   }
123 }
124 
125 /// Dump the name encoded in the type tag.
126 static void dumpTypeTagName(raw_ostream &OS, dwarf::Tag T) {
127   StringRef TagStr = TagString(T);
128   if (!TagStr.startswith("DW_TAG_") || !TagStr.endswith("_type"))
129     return;
130   OS << TagStr.substr(7, TagStr.size() - 12) << " ";
131 }
132 
133 /// Recursively dump the DIE type name when applicable.
134 static void dumpTypeName(raw_ostream &OS, const DWARFDie &Die) {
135   DWARFDie D = Die.getAttributeValueAsReferencedDie(DW_AT_type);
136 
137   if (!D.isValid())
138     return;
139 
140   if (const char *Name = D.getName(DINameKind::LinkageName)) {
141     OS << Name;
142     return;
143   }
144 
145   // FIXME: We should have pretty printers per language. Currently we print
146   // everything as if it was C++ and fall back to the TAG type name.
147   const dwarf::Tag T = D.getTag();
148   switch (T) {
149   case DW_TAG_array_type:
150   case DW_TAG_pointer_type:
151   case DW_TAG_ptr_to_member_type:
152   case DW_TAG_reference_type:
153   case DW_TAG_rvalue_reference_type:
154     break;
155   default:
156     dumpTypeTagName(OS, T);
157   }
158 
159   // Follow the DW_AT_type if possible.
160   dumpTypeName(OS, D);
161 
162   switch (T) {
163   case DW_TAG_array_type:
164     OS << "[]";
165     break;
166   case DW_TAG_pointer_type:
167     OS << '*';
168     break;
169   case DW_TAG_ptr_to_member_type:
170     OS << '*';
171     break;
172   case DW_TAG_reference_type:
173     OS << '&';
174     break;
175   case DW_TAG_rvalue_reference_type:
176     OS << "&&";
177     break;
178   default:
179     break;
180   }
181 }
182 
183 static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
184                           uint32_t *OffsetPtr, dwarf::Attribute Attr,
185                           dwarf::Form Form, unsigned Indent,
186                           DIDumpOptions DumpOpts) {
187   if (!Die.isValid())
188     return;
189   const char BaseIndent[] = "            ";
190   OS << BaseIndent;
191   OS.indent(Indent + 2);
192   auto attrString = AttributeString(Attr);
193   if (!attrString.empty())
194     WithColor(OS, syntax::Attribute) << attrString;
195   else
196     WithColor(OS, syntax::Attribute).get() << format("DW_AT_Unknown_%x", Attr);
197 
198   if (DumpOpts.Verbose || DumpOpts.ShowForm) {
199     auto formString = FormEncodingString(Form);
200     if (!formString.empty())
201       OS << " [" << formString << ']';
202     else
203       OS << format(" [DW_FORM_Unknown_%x]", Form);
204   }
205 
206   DWARFUnit *U = Die.getDwarfUnit();
207   DWARFFormValue formValue(Form);
208 
209   if (!formValue.extractValue(U->getDebugInfoExtractor(), OffsetPtr,
210                               U->getFormParams(), U))
211     return;
212 
213   OS << "\t(";
214 
215   StringRef Name;
216   std::string File;
217   auto Color = syntax::Enumerator;
218   if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
219     Color = syntax::String;
220     if (const auto *LT = U->getContext().getLineTableForUnit(U))
221       if (LT->getFileNameByIndex(
222               formValue.getAsUnsignedConstant().getValue(),
223               U->getCompilationDir(),
224               DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
225         File = '"' + File + '"';
226         Name = File;
227       }
228   } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
229     Name = AttributeValueString(Attr, *Val);
230 
231   if (!Name.empty())
232     WithColor(OS, Color) << Name;
233   else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
234     OS << *formValue.getAsUnsignedConstant();
235   else if (Attr == DW_AT_high_pc && !DumpOpts.ShowForm && !DumpOpts.Verbose &&
236            formValue.getAsUnsignedConstant()) {
237     if (DumpOpts.ShowAddresses) {
238       // Print the actual address rather than the offset.
239       uint64_t LowPC, HighPC, Index;
240       if (Die.getLowAndHighPC(LowPC, HighPC, Index))
241         OS << format("0x%016" PRIx64, HighPC);
242       else
243         formValue.dump(OS, DumpOpts);
244     }
245   } else if (Attr == DW_AT_location || Attr == DW_AT_frame_base ||
246              Attr == DW_AT_data_member_location ||
247              Attr == DW_AT_GNU_call_site_value)
248     dumpLocation(OS, formValue, U, sizeof(BaseIndent) + Indent + 4, DumpOpts);
249   else
250     formValue.dump(OS, DumpOpts);
251 
252   // We have dumped the attribute raw value. For some attributes
253   // having both the raw value and the pretty-printed value is
254   // interesting. These attributes are handled below.
255   if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin) {
256     if (const char *Name = Die.getAttributeValueAsReferencedDie(Attr).getName(
257             DINameKind::LinkageName))
258       OS << " \"" << Name << '\"';
259   } else if (Attr == DW_AT_type) {
260     OS << " \"";
261     dumpTypeName(OS, Die);
262     OS << '"';
263   } else if (Attr == DW_AT_APPLE_property_attribute) {
264     if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
265       dumpApplePropertyAttribute(OS, *OptVal);
266   } else if (Attr == DW_AT_ranges) {
267     const DWARFObject &Obj = Die.getDwarfUnit()->getContext().getDWARFObj();
268     dumpRanges(Obj, OS, Die.getAddressRanges(), U->getAddressByteSize(),
269                sizeof(BaseIndent) + Indent + 4, DumpOpts);
270   }
271 
272   OS << ")\n";
273 }
274 
275 bool DWARFDie::isSubprogramDIE() const { return getTag() == DW_TAG_subprogram; }
276 
277 bool DWARFDie::isSubroutineDIE() const {
278   auto Tag = getTag();
279   return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
280 }
281 
282 Optional<DWARFFormValue> DWARFDie::find(dwarf::Attribute Attr) const {
283   if (!isValid())
284     return None;
285   auto AbbrevDecl = getAbbreviationDeclarationPtr();
286   if (AbbrevDecl)
287     return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U);
288   return None;
289 }
290 
291 Optional<DWARFFormValue>
292 DWARFDie::find(ArrayRef<dwarf::Attribute> Attrs) const {
293   if (!isValid())
294     return None;
295   auto AbbrevDecl = getAbbreviationDeclarationPtr();
296   if (AbbrevDecl) {
297     for (auto Attr : Attrs) {
298       if (auto Value = AbbrevDecl->getAttributeValue(getOffset(), Attr, *U))
299         return Value;
300     }
301   }
302   return None;
303 }
304 
305 Optional<DWARFFormValue>
306 DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
307   if (!isValid())
308     return None;
309   if (auto Value = find(Attrs))
310     return Value;
311   if (auto Die = getAttributeValueAsReferencedDie(DW_AT_abstract_origin)) {
312     if (auto Value = Die.findRecursively(Attrs))
313       return Value;
314   }
315   if (auto Die = getAttributeValueAsReferencedDie(DW_AT_specification)) {
316     if (auto Value = Die.findRecursively(Attrs))
317       return Value;
318   }
319   return None;
320 }
321 
322 DWARFDie
323 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
324   if (auto SpecRef = toReference(find(Attr))) {
325     if (auto SpecUnit = U->getUnitSection().getUnitForOffset(*SpecRef))
326       return SpecUnit->getDIEForOffset(*SpecRef);
327   }
328   return DWARFDie();
329 }
330 
331 Optional<uint64_t> DWARFDie::getRangesBaseAttribute() const {
332   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
333 }
334 
335 Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
336   if (auto FormValue = find(DW_AT_high_pc)) {
337     if (auto Address = FormValue->getAsAddress()) {
338       // High PC is an address.
339       return Address;
340     }
341     if (auto Offset = FormValue->getAsUnsignedConstant()) {
342       // High PC is an offset from LowPC.
343       return LowPC + *Offset;
344     }
345   }
346   return None;
347 }
348 
349 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
350                                uint64_t &SectionIndex) const {
351   auto F = find(DW_AT_low_pc);
352   auto LowPcAddr = toAddress(F);
353   if (!LowPcAddr)
354     return false;
355   if (auto HighPcAddr = getHighPC(*LowPcAddr)) {
356     LowPC = *LowPcAddr;
357     HighPC = *HighPcAddr;
358     SectionIndex = F->getSectionIndex();
359     return true;
360   }
361   return false;
362 }
363 
364 DWARFAddressRangesVector DWARFDie::getAddressRanges() const {
365   if (isNULL())
366     return DWARFAddressRangesVector();
367   // Single range specified by low/high PC.
368   uint64_t LowPC, HighPC, Index;
369   if (getLowAndHighPC(LowPC, HighPC, Index))
370     return {{LowPC, HighPC, Index}};
371 
372   // Multiple ranges from .debug_ranges section.
373   auto RangesOffset = toSectionOffset(find(DW_AT_ranges));
374   if (RangesOffset) {
375     DWARFDebugRangeList RangeList;
376     if (U->extractRangeList(*RangesOffset, RangeList))
377       return RangeList.getAbsoluteRanges(U->getBaseAddress());
378   }
379   return DWARFAddressRangesVector();
380 }
381 
382 void DWARFDie::collectChildrenAddressRanges(
383     DWARFAddressRangesVector &Ranges) const {
384   if (isNULL())
385     return;
386   if (isSubprogramDIE()) {
387     const auto &DIERanges = getAddressRanges();
388     Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
389   }
390 
391   for (auto Child : children())
392     Child.collectChildrenAddressRanges(Ranges);
393 }
394 
395 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
396   for (const auto &R : getAddressRanges()) {
397     if (R.LowPC <= Address && Address < R.HighPC)
398       return true;
399   }
400   return false;
401 }
402 
403 const char *DWARFDie::getSubroutineName(DINameKind Kind) const {
404   if (!isSubroutineDIE())
405     return nullptr;
406   return getName(Kind);
407 }
408 
409 const char *DWARFDie::getName(DINameKind Kind) const {
410   if (!isValid() || Kind == DINameKind::None)
411     return nullptr;
412   // Try to get mangled name only if it was asked for.
413   if (Kind == DINameKind::LinkageName) {
414     if (auto Name = dwarf::toString(
415             findRecursively({DW_AT_MIPS_linkage_name, DW_AT_linkage_name}),
416             nullptr))
417       return Name;
418   }
419   if (auto Name = dwarf::toString(findRecursively(DW_AT_name), nullptr))
420     return Name;
421   return nullptr;
422 }
423 
424 uint64_t DWARFDie::getDeclLine() const {
425   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
426 }
427 
428 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
429                               uint32_t &CallColumn,
430                               uint32_t &CallDiscriminator) const {
431   CallFile = toUnsigned(find(DW_AT_call_file), 0);
432   CallLine = toUnsigned(find(DW_AT_call_line), 0);
433   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
434   CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
435 }
436 
437 /// Helper to dump a DIE with all of its parents, but no siblings.
438 static unsigned dumpParentChain(DWARFDie Die, raw_ostream &OS, unsigned Indent,
439                                 DIDumpOptions DumpOpts) {
440   if (!Die)
441     return Indent;
442   Indent = dumpParentChain(Die.getParent(), OS, Indent, DumpOpts);
443   Die.dump(OS, Indent, DumpOpts);
444   return Indent + 2;
445 }
446 
447 void DWARFDie::dump(raw_ostream &OS, unsigned Indent,
448                     DIDumpOptions DumpOpts) const {
449   if (!isValid())
450     return;
451   DWARFDataExtractor debug_info_data = U->getDebugInfoExtractor();
452   const uint32_t Offset = getOffset();
453   uint32_t offset = Offset;
454   if (DumpOpts.ShowParents) {
455     DumpOpts.ShowParents = false;
456     Indent = dumpParentChain(getParent(), OS, Indent, DumpOpts);
457   }
458 
459   if (debug_info_data.isValidOffset(offset)) {
460     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
461     if (DumpOpts.ShowAddresses)
462       WithColor(OS, syntax::Address).get() << format("\n0x%8.8x: ", Offset);
463 
464     if (abbrCode) {
465       auto AbbrevDecl = getAbbreviationDeclarationPtr();
466       if (AbbrevDecl) {
467         auto tagString = TagString(getTag());
468         if (!tagString.empty())
469           WithColor(OS, syntax::Tag).get().indent(Indent) << tagString;
470         else
471           WithColor(OS, syntax::Tag).get().indent(Indent)
472               << format("DW_TAG_Unknown_%x", getTag());
473 
474         if (DumpOpts.Verbose)
475           OS << format(" [%u] %c", abbrCode,
476                        AbbrevDecl->hasChildren() ? '*' : ' ');
477         OS << '\n';
478 
479         // Dump all data in the DIE for the attributes.
480         for (const auto &AttrSpec : AbbrevDecl->attributes()) {
481           if (AttrSpec.Form == DW_FORM_implicit_const) {
482             // We are dumping .debug_info section ,
483             // implicit_const attribute values are not really stored here,
484             // but in .debug_abbrev section. So we just skip such attrs.
485             continue;
486           }
487           dumpAttribute(OS, *this, &offset, AttrSpec.Attr, AttrSpec.Form,
488                         Indent, DumpOpts);
489         }
490 
491         DWARFDie child = getFirstChild();
492         if (DumpOpts.ShowChildren && DumpOpts.RecurseDepth > 0 && child) {
493           DumpOpts.RecurseDepth--;
494           while (child) {
495             child.dump(OS, Indent + 2, DumpOpts);
496             child = child.getSibling();
497           }
498         }
499       } else {
500         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
501            << abbrCode << '\n';
502       }
503     } else {
504       OS.indent(Indent) << "NULL\n";
505     }
506   }
507 }
508 
509 LLVM_DUMP_METHOD void DWARFDie::dump() const { dump(llvm::errs(), 0); }
510 
511 DWARFDie DWARFDie::getParent() const {
512   if (isValid())
513     return U->getParent(Die);
514   return DWARFDie();
515 }
516 
517 DWARFDie DWARFDie::getSibling() const {
518   if (isValid())
519     return U->getSibling(Die);
520   return DWARFDie();
521 }
522 
523 DWARFDie DWARFDie::getFirstChild() const {
524   if (isValid())
525     return U->getFirstChild(Die);
526   return DWARFDie();
527 }
528 
529 iterator_range<DWARFDie::attribute_iterator> DWARFDie::attributes() const {
530   return make_range(attribute_iterator(*this, false),
531                     attribute_iterator(*this, true));
532 }
533 
534 DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End)
535     : Die(D), AttrValue(0), Index(0) {
536   auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
537   assert(AbbrDecl && "Must have abbreviation declaration");
538   if (End) {
539     // This is the end iterator so we set the index to the attribute count.
540     Index = AbbrDecl->getNumAttributes();
541   } else {
542     // This is the begin iterator so we extract the value for this->Index.
543     AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
544     updateForIndex(*AbbrDecl, 0);
545   }
546 }
547 
548 void DWARFDie::attribute_iterator::updateForIndex(
549     const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I) {
550   Index = I;
551   // AbbrDecl must be valid before calling this function.
552   auto NumAttrs = AbbrDecl.getNumAttributes();
553   if (Index < NumAttrs) {
554     AttrValue.Attr = AbbrDecl.getAttrByIndex(Index);
555     // Add the previous byte size of any previous attribute value.
556     AttrValue.Offset += AttrValue.ByteSize;
557     AttrValue.Value.setForm(AbbrDecl.getFormByIndex(Index));
558     uint32_t ParseOffset = AttrValue.Offset;
559     auto U = Die.getDwarfUnit();
560     assert(U && "Die must have valid DWARF unit");
561     bool b = AttrValue.Value.extractValue(U->getDebugInfoExtractor(),
562                                           &ParseOffset, U->getFormParams(), U);
563     (void)b;
564     assert(b && "extractValue cannot fail on fully parsed DWARF");
565     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;
566   } else {
567     assert(Index == NumAttrs && "Indexes should be [0, NumAttrs) only");
568     AttrValue.clear();
569   }
570 }
571 
572 DWARFDie::attribute_iterator &DWARFDie::attribute_iterator::operator++() {
573   if (auto AbbrDecl = Die.getAbbreviationDeclarationPtr())
574     updateForIndex(*AbbrDecl, Index + 1);
575   return *this;
576 }
577